JP2000213549A - Rotation member supporting device for automotive auxiliary machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotation member supporting device for an automotive auxiliary machine capable of ensuring a long durable life even under a high load and temperature environment. SOLUTION: The material and surface hardness of a bearing ring after hardening and high-temperature tempering treatment are made stabilized under high temperature and excellent in a rolling fatigue characteristic and abrasion resistance, to ensure a long durable life even in a rotating shaft supporting device used under a high load and temperature environment, by forming the bearing ring of a pair of ball bearing 4, for supporting a rotor rotating shaft 3, of steel material containing a Si of 0.3% or more and 3.0% or less in mass % as an alloy element, and containing singly or compositely Ni of 0.1% or more and 3.0% or less, V of 0.05% or more and 1.0% or less, and Mo of 0.05% or more and less 0.25%, to make the surface hardness of the bearing ring Rockwell hardness HRC 58 or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a supporting device for rotatably supporting a rotating member of an auxiliary machine for an automobile which is driven to rotate by an engine output.

[0002]

2. Description of the Related Art There are compressors for alternators and air conditioners as automotive auxiliary machines utilizing engine output. In each of these, rotational torque is transmitted from a crankshaft of an engine via a belt.

FIG. 1 shows a basic configuration of an alternator according to a first embodiment of the present invention. This alternator
A rotor rotating shaft 3 on which a rotor 2 is mounted is mounted on a pair of ball bearings 4 on a pair of frames 1 a and 1 b forming a housing.
It is rotatably supported by. A rotor coil 5 is attached to the rotor 2, and three stator coils 7 having a phase of 120 ° are attached to a stator 6 arranged on the outer periphery of the rotor 2.
Is attached.

The rotor rotating shaft 3 is rotatably driven by a rotating torque transmitted by a belt (not shown) to a pulley 10 attached to the tip of the rotor rotating shaft 3, and is attached out of phase when electricity flows through the rotor coil 5. An alternating current is induced in each of the three stator coils 7. This induced 3
The alternating current of the phase is full-wave rectified by the rectifier 11 and charged in the battery.

[0005] The pulley 10 is mounted on the rotor rotating shaft 3 in a cantilever state, and vibration is generated with high-speed rotation of the rotor rotating shaft 3. Therefore, the ball bearing 4 supporting the pulley 10 side is particularly severe. Load.

FIG. 3 shows a basic configuration of a compressor for an air conditioner according to a second embodiment of the present invention. In this compressor, a small-diameter portion 19 is provided on one end side of a compressor case 18, and a rotor 21 containing an electromagnetic coil 20 is rotatably supported by double-row ball bearings 22 on the outer periphery of the small-diameter portion 19. In addition, the small diameter portion 19
A rotating shaft 23 of the compressor is passed through the inner periphery of the rotor 21. A clutch hub 24 attached to the tip of the rotating shaft 23
The rotor 21 and the clutch hub 24 form an electromagnetic clutch.

The rotor 21 is rotationally driven by a rotational torque transmitted by a belt (not shown) to a pulley 25 provided on an outer peripheral surface of the rotor 21, and when the electromagnetic coil 20 is excited, the rotor 21 and the clutch hub 24 are engaged. At the same time, the rotation torque is transmitted to the rotation shaft 23 of the compressor. The electromagnetic clutch is turned on and off based on the output of a temperature sensor or the like mounted in the vehicle.

When the electromagnetic clutch is disengaged, the rotor 21 rotates at a high speed with no load, and the load changes abruptly at the moment when the electromagnetic clutch is disengaged. The ball bearing 22 supporting the rotor 21 receives a severe load similarly to the ball bearing 4 of the rotor rotating shaft 3 described above.

In recent years, in order to cover the increase in weight due to the enhancement of safety equipment and electrical components and maintain high vehicle performance, the auxiliary equipment such as the alternator and compressor described above has been reduced in size and weight and improved in performance. Has been required. In response to these requirements, the pulley ratio for transmitting the rotational torque to the auxiliary machine is designed to be large, and the rotating member to which the rotational torque is transmitted is rotated at a higher speed. Also, the belt tension has been increased to cope with this high-speed rotation. For this reason, the rolling bearings that support these rotating members are subjected to severer loads described above, and are used in even higher temperature environments due to an increase in the amount of heat generated by an increase in the rotation speed. ing.

Conventionally, as a material for the rolling bearing of the rotating member, a material obtained by quenching a high carbon chromium bearing steel such as SUJ2 or a material obtained by carburizing and quenching a case hardened steel such as SCM420 and SCr420 is used. . These bearing materials are used to prevent dimensional changes when the temperature rises.
It is used after tempering at a high temperature of 00 ° C. or more to stabilize the quenched structure. However, when these bearing materials are tempered at high temperatures, the hardness is significantly reduced, the rolling fatigue characteristics and wear resistance are deteriorated, and there is a problem that the durability life of the rotating member supporting device cannot be sufficiently secured. .

SUMMARY OF THE INVENTION An object of the present invention is to provide a rotating member support device for an auxiliary machine for an automobile which can ensure a long durable life even under a high load and high temperature environment.

[0012]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to the rotation of an auxiliary machine for an automobile in which a rotating member rotatably driven by an engine output is rotatably supported on a stationary member by a rolling bearing. In the member supporting apparatus, the race of the rolling bearing contains, as an alloy element, 0.3% or more and 3.0% or less of Si by mass% and Ni of 0.1% or less.
1% or more and 3.0% or less, V is 0.05% or more and 1.0% or less.
% Or less, and Mo is formed from a steel material containing 0.05% or more and less than 0.25% singly or in combination, and the surface hardness of this bearing ring is set to Rockwell hardness HRC 58 or more. is there.

[0013] The alloy element of the steel material forming the bearing ring contains 0.3 to 3.0% of Si.
Is due to the effect of suppressing softening in a high-temperature range and improving the heat resistance of the rolling bearing. If the content is less than 0.3%, the effect cannot be obtained, and the heat resistance improves with an increase in the Si content. However, even if it is contained in a large amount exceeding 3.0%, the effect is saturated, and hot workability and machinability are reduced.

Ni is 0.1-3.0%, V is 0.05-
The reason for containing 1.0% and Mo individually or in combination of 0.05 to less than 0.25% is as follows.

Ni forms a solid solution in steel to strengthen the matrix, suppresses the structural change in the rolling fatigue process, particularly when the bearing is used at a high temperature, and has a hardness in a high temperature range. Is also suppressed. Therefore, Ni has an effect of improving rolling fatigue characteristics and wear resistance under a high load and high temperature environment. Ni also has the effect of improving corrosion resistance. In order to obtain these effects, it is necessary to contain 0.1% or more of Ni.
Limited to 1%. However, when Ni is contained in excess of 3.0%, a large amount of retained austenite is generated during the quenching treatment, so that a predetermined hardness cannot be obtained and the cost of the steel material becomes high. Limited to 0%.

V combines with carbon to precipitate fine carbides, refines crystal grains to improve strength and toughness, suppresses softening during high-temperature tempering, and also suppresses softening in high-temperature regions. I do. Therefore, like Ni, V has the effect of improving rolling fatigue characteristics and wear resistance under high load and high temperature environments. To get this effect,
The lower limit of the V content was limited to 0.05%. The upper limit is 1.0
The reason for limiting to% is that if a large amount of V is contained in excess of 1.0%, machinability and hot workability are reduced.

Mo improves the hardenability of steel, prevents temper embrittlement, and also suppresses softening at high temperatures. Therefore, Mo also has the effect of improving rolling fatigue characteristics and wear resistance under a high load and high temperature environment. To obtain this effect, the lower limit of the Mo content is limited to 0.05%. When the Mo content is set to 0.25% or more, the machinability decreases and the cost of steel material also increases.
%.

[0018] By the action of each of the above-mentioned alloy elements, the bearing ring is 3
Even if tempering is performed at a high temperature of 00 ° C. or more, a high surface hardness of Rockwell hardness HRC 58 or more can be obtained. By performing the tempering treatment at such a high temperature,
It stabilizes the quenched structure to prevent dimensional changes when the temperature rises, secures high surface hardness, improves rolling fatigue characteristics and wear resistance, and extends the durable life of the rotating member support device for automotive accessories. It can be sufficiently secured even under a high load and high temperature environment.

In the above steel material, M
By adding n at 0.2% or more and 1.5% or less and Cr at 0.3 or more and 5.0% or less, the rolling fatigue characteristics and wear resistance of the bearing ring can be further improved.

That is, both Mn and Cr improve the hardenability of the steel material, Mn forms a solid solution in the steel to strengthen the steel, and Cr forms carbides to strengthen the steel. The lower limit of the Mn content is set to 0.2% and the lower limit of the Cr content is set to 0.3% in order to obtain these effects. The upper limit of the Mn content is set to 1.5% in order to avoid a decrease in machinability, and the upper limit of the Cr content is set to 5.0% because of the formation of large carbides. This is to prevent the conversion.

Forming a carbonitrided layer on the surface of said race;
By setting the amount of retained austenite in the carbonitrided layer to 10% by volume or more, high toughness is imparted to the surface layer of the bearing ring, crack generation and propagation are suppressed, and the durable life of the rotating member supporting device is further extended. Can be.

That is, when the nitrogen content of the surface layer is increased by the carbonitriding treatment, the Ms point (martensite transformation start temperature) of the surface layer is lowered, and when this is quenched, untransformed austenite is increased in the surface layer. Remains. Retained austenite has high toughness and work hardening characteristics, and functions to suppress the generation and propagation of cracks. In the surface layer having a lowered Ms point, the martensitic transformation starts later than the inside and the amount of transformation is smaller than the inside, so that residual compressive stress is formed in the surface layer and the fatigue strength of the surface layer is improved. I do.
The reason why the amount of retained austenite in the carbonitrided layer is set to 10% by volume or more is to obtain these effects. On the other hand, since the amount of retained austenite is reduced by high-temperature tempering, the dimensional change due to decomposition of the retained austenite during use can be suppressed.

The above-described rotating member supporting device for an auxiliary machine for an automobile includes a rotating member supporting device for an alternator rotatably supporting a rotor rotating shaft having a pulley attached at one end by a ball bearing, and a pulley provided on an outer peripheral surface. The present invention can be applied to a rotating member supporting device of a compressor in which a rotor of an electromagnetic clutch in which an electromagnetic coil is housed is rotatably supported by a ball bearing.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 and FIG.
1 shows an alternator rotating member support device according to an embodiment of the present invention. In this alternator, as described above, a rotor rotating shaft 3 as a rotating member having a rotor 2 mounted thereon is rotatably supported by a pair of ball bearings 4 on a pair of frames 1a and 1b forming a housing. . A rotor coil 5 is mounted on the rotor 2, and three stator coils 7 with a phase of 120 ° are mounted on a stator 6 arranged on the outer periphery of the rotor 2. A slip ring 8 and a cooling fan 9 are also attached to the rotor rotating shaft 3.

The rotor rotating shaft 3 is driven to rotate by a rotating torque transmitted by a belt (not shown) to a pulley 10 attached to a tip end thereof. When the rotor rotating shaft 3 is driven to rotate, electricity from the battery flows to the rotor coil 5 via the slip ring 8, and an alternating current is induced in each of the three windings of the stator coil 7 attached with the phase shifted. . The induced three-phase alternating current is full-wave rectified by the rectifier 11 and charged into the battery.

FIG. 2 shows an enlarged view of the ball bearing 4 that supports the rotor rotating shaft 3. The ball bearing 4 is provided with raceway grooves 14 and 15 having an arc-shaped cross section on the inner diameter surface of the outer ring 12 and the outer diameter surface of the inner ring 13, and a plurality of balls 16 are held between the raceway grooves 14 and 15. 17 is held. Outer ring 12
The inner ring 13 is made of steel having the chemical components shown in Table 1 below as an example, heated to 840 ° C. to 860 ° C., quenched into a salt bath, and tempered at 350 ° C. at a high temperature. In some examples, heating before quenching was performed in a carburizing atmosphere to which ammonia gas was added, and carbonitriding was also performed.

The outer race 12 and the inner race 13 of the ball bearing 4 of the above embodiment have a surface hardness of Rockwell hardness HRC 58 or more as a result of inspection by sample extraction. The amount of retained austenite in the carbonitrided layer was 10% by volume or more.

FIGS. 3 and 4 show a rotary member supporting device for a compressor according to a second embodiment. As described above, this compressor is provided with a small-diameter portion 19 on one end side of a compressor case 18, and a rotor 21 as a rotating member accommodating an electromagnetic coil 20 is provided on the outer periphery of the small-diameter portion 19 in a double-row ball bearing 22. It is rotatably supported by.
Further, on the inner peripheral side of the small diameter portion 19, the rotating shaft 2 of the compressor is provided.
3 through which the clutch hub 2 attached
4 is disposed adjacent to one end of the rotor 21, and the rotor 21 and the clutch hub 24 form an electromagnetic clutch.

The rotor 21 is rotationally driven by a rotational torque transmitted by a belt (not shown) to a pulley 25 provided on an outer peripheral surface of the rotor 21, and when the electromagnetic coil 20 is excited, the rotor 21 and the clutch hub 24 are engaged. At the same time, the rotation torque is transmitted to the rotation shaft 23 of the compressor.

FIG. 4 is an enlarged view of a double row ball bearing 22 for supporting the rotor. The ball bearing 22 is provided with two raceway grooves 28 and 29 each having an arc-shaped cross section on the inner diameter surface of the outer ring 26 and the outer diameter surface of the inner ring 27.
A plurality of balls 30 are held by a holder 31 between the balls. The outer ring 26 and the inner ring 27 are made of steel having the chemical components shown in the examples in Table 1 as a raw material, heated to 840 ° C. to 860 ° C., and then quenched into a salt bath, similarly to the above-described alternator ball bearing 4. High-temperature tempering was carried out at a temperature of ° C., and some of them were subjected to carbonitriding treatment by heating before quenching in a carburizing atmosphere to which ammonia gas was added.

[0031]

[Table 1]

Examples and comparative examples will be described below.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A ball bearing using a bearing ring manufactured in the same form as that of the ball bearing shown in FIG. 2 and made by subjecting the above-described quenching and tempering treatments to steels having 11 kinds of chemical components shown in Table 1. (Examples 1 to 11 in Table 1) were prepared. Ball bearings using bearing rings manufactured by performing carbonitriding on some of the steel materials shown in Examples 1 to 11 (Examples 12 to 1 in Table 1)
6) was also prepared. All bearing dimensions are 17m inside diameter
m, outer diameter 47 mm, width 14 mm.

[0034]

[Comparative Example] Using high carbon chromium bearing height SUJ2 as material
A ball bearing using a bearing ring heat-treated under the same conditions as in the above-described embodiment (Comparative Example 1 in Table 1), and a steel having three kinds of chemical components out of the range of the chemical components of the present application is used as a material. Ball bearings using bearing rings heat-treated under the conditions (Comparative Examples 2 to 4 in Table 1), and ball bearings using bearing rings manufactured by also performing carbonitriding on these steel materials (Comparative Example 5 in Table 1) ~
8) was prepared. The form and dimensions of each bearing are the same as in the embodiment.

Each of the ball bearings of the above Examples and Comparative Examples was mounted on a rotating shaft of a durability tester, and a high-temperature durability life test was performed.

The test conditions are as follows. The number of samples N in the test was 5. Load: 3.2 kN Revolution: 18000 rpm Lubrication: Grease lubrication Test temperature: 150 ° C. The test results are shown in Table 1. The durability life in the table is L1
Zero life (90% of sample can be used without damage)
Was evaluated. The life ratio was based on the durable life of Comparative Example 1.

The ball bearing of the embodiment is a comparative example 1 in which a conventional SUJ2 is used as a raw material and a raceway ring is quenched and tempered.
, All have excellent values of 2.4 times or more. In contrast, the life ratios of the ball bearings of the comparative examples, including those subjected to carbonitriding, are less than twice.

The same high-temperature durability life test was carried out for the double row ball bearings shown in FIG. 4, but the ball bearings of the examples had the same excellent durability as the single row described above. It was confirmed that it had a lifetime.

[0039]

As described above, the apparatus for supporting a rotating member of an automotive auxiliary machine according to the present invention provides a rolling element bearing ring for supporting a rotating member, wherein the alloy element contains 0.3% by mass of Si and 0.3% by mass of Si.
Not less than 3.0%, Ni is not less than 0.1% and not more than 3.0%, V is not less than 0.05% and not more than 1.0%,
Mo was formed from a steel material containing 0.05% or more and less than 0.25% Mo alone or in combination, and the surface hardness of this bearing ring was set to Rockwell hardness HRC58 or more.
The material and surface hardness of the bearing ring after high-temperature tempering are stable even at high temperatures and have excellent rolling fatigue characteristics and wear resistance. Even a long durability life can be ensured. Also, by adding Mn of 0.2% or more and 1.5% or less and Cr of 0.3 or more and 5.0% or less in mass% as an alloying element, the rolling contact fatigue characteristics and wear resistance of the raceway are added. The carbonitrided layer is formed on the surface of the bearing ring, and the amount of retained austenite in the carbonitrided layer is reduced by 10%.
By setting the volume% or more, high toughness is imparted to the surface layer of the bearing ring, generation and propagation of cracks can be suppressed, and the durable life of the rotating member supporting device can be further extended.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an alternator in which a rotating member supporting device according to a first embodiment is incorporated.

FIG. 2 is an enlarged longitudinal sectional view showing the ball bearing of FIG. 1;

FIG. 3 is a longitudinal sectional view of a compressor in which a rotating member supporting device according to a second embodiment is incorporated.

FIG. 4 is an enlarged longitudinal sectional view showing the ball bearing of FIG. 3;

[Explanation of symbols]

 1a, 1b Frame 2 Rotor 3 Rotor shaft 4 Ball bearing 5 Rotor coil 6 Stator 7 Stator coil 8 Slip ring 9 Fan 10 Pulley 11 Rectifier 12 Outer ring 13 Inner ring 14, 15 Track groove 16 Ball 17 Cage 18 Case 19 Small diameter portion Reference Signs List 20 electromagnetic coil 21 rotor 22 ball bearing 23 rotating shaft 24 clutch hub 25 pulley 26 outer ring 27 inner ring 28, 29 raceway groove 30 ball 31 cage

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // H02K 7/08 H02K 7/08 Z (72) Inventor Hiroshi Kawamura 1578 Higashikaizuka, Iwata City, Shizuoka Prefecture In-house F term (reference) 3J101 AA02 AA32 AA42 AA52 AA62 BA70 DA02 DA03 EA02 EA03 FA31 GA60 5H607 AA01 BB01 BB14 CC01 CC03 CC05 DD03 DD08 EE04 FF11 FF24 GG04 GG08 KK00

Claims (5)

[Claims] 1. A device for supporting a rotating member of an automobile auxiliary machine, wherein a rotating member rotatably driven by an engine output is rotatably supported on a stationary member by a rolling bearing, wherein a race of the rolling bearing has a mass as an alloy element. %, 0.3% of Si
% Or more and 3.0% or less, Ni is 0.1% or more and 3.0% or less, V is 0.05% or more and 1.0% or less, and Mo is 0.05% or more and 0% or more. A rotating member support apparatus for an auxiliary machine for an automobile, wherein the bearing ring is formed of a steel material containing less than 25%, alone or in combination, and has a surface hardness of at least Rockwell hardness HRC58. 2. The steel material has a mass% as an alloying element,
2. The rotating member support device for an auxiliary machine for an automobile according to claim 1, wherein Mn is added in an amount of 0.2% to 1.5% and Cr is added in a range of 0.3% to 5.0%. 3. The rotating member supporting apparatus for an auxiliary machine for an automobile according to claim 1, wherein a carbonitrided layer is formed on a surface of the raceway, and a residual austenite amount of the carbonitrided layer is 10% by volume or more. . 4. The vehicle according to claim 1, wherein the auxiliary machine is an alternator, the rotating member is a rotor rotating shaft having a pulley attached to one end thereof, and the rolling bearing is a ball bearing. Rotary member support device for automotive accessories. 5. The motor vehicle accessory is a compressor, the rotating member is a rotor of an electromagnetic clutch in which a pulley is provided on an outer peripheral surface and an electromagnetic coil is housed, and the rolling bearing is a ball bearing. 4. A rotating member supporting device for an auxiliary machine for an automobile according to any one of claims 1 to 3.