JP2007078120A - Tripod constant velocity universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tripod constant velocity universal joint capable of providing excellent durability by surely preventing the frictional surface thereof from being worn by fretting and from being peeled off by flaking. <P>SOLUTION: In this tripod constant velocity universal joint, an inner diameter is set so that the bearing ring 8 of a roller unit 7 can be rollingly rotated on each of three leg shafts 2. A first lubricating grease is held between the bearing ring 8 and rollers 9. A second lubricating grease is held on a sliding surface between the bearing ring 8 and the leg shafts 2, a sliding surface between the rollers 9 and a track groove 6, or these both sliding surfaces. The first lubricating grease is thickened with an urea compound and resistant against fretting with a worn amount of 15 mg or less by *** test (ASTM D4170). The second lubricating grease is a wear resistant lubricating grease containing an extreme-pressure agent or a solid lubricant. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a tripod type constant velocity universal joint, and more particularly to a tripod type constant velocity universal joint using a predetermined lubricating grease.

  For example, a tripod type constant velocity universal joint is known in order to transmit rotational force from an automobile engine to wheels at a constant speed.

  As shown in FIGS. 1 to 4, the tripod type constant velocity universal joint includes a tripod shaft portion 3 having three leg shafts 2 around the tip of the shaft 1 and a cylindrical shape into which the tripod shaft portion 3 can be inserted. It consists of a joint shaft part 5 provided with a part 4 at one end.

  In the tripod type constant velocity universal joint, three track grooves 6 extending in the axial direction are formed on the inner peripheral surface of the cylindrical portion 4, and needle rollers 10 are respectively provided on the three leg shafts 2. The bearing ring 8 of the roller unit 7 (so-called spherical roller) provided in the state is rotatably fitted, and the tripod shaft portion is so guided that the roller 9 of the roller unit 7 is guided to a pair of side wall surfaces forming the track groove 6. 3 is fitted into the cylindrical portion 4 of the joint shaft portion 5.

  This tripod type constant velocity universal joint has a rotational force not only when the tripod shaft portion 3 and the joint shaft portion 5 are linearly coupled but also when the joint has an operating angle θ as shown in FIG. However, when the joint suddenly takes an operating angle θ, the roller 9 of the roller unit 7 suddenly contacts the side wall surface of the track groove 6, or the bearing ring 8 of the roller unit 7 and the leg shaft 2 And the like suddenly come into sliding contact with each other, a slide resistance is generated in the axial direction, which may generate an induced thrust force (see Patent Document 1).

  Such sliding resistance and induced thrust force cause vibration and noise of the car body of the automobile, and lower the performance of the automobile and especially the design freedom of the undercarriage. It is preferable to reduce opportunities.

  Such a tripod type constant velocity universal joint, like other constant velocity universal joints (also referred to as constant velocity joints), is filled with lubricating grease, which is used for vibration reduction and constant velocity universal joints. It plays a big role in improving durability.

  General constant velocity universal joint greases include sulfur-phosphorus extreme pressure grease and lithium-based extreme pressure grease containing molybdenum disulfide, but they are extremely wear-resistant under high surface pressure and are durable. In terms of performance, it is not satisfactory, and the slidability is not sufficient.

  In recent years, in order to improve wear resistance and durability, grease in which an extreme pressure agent or an antiwear agent is added to urea grease is known. For example, excessive grease is used to suppress wear and prevent flaking. A grease in which basic sodium sulfonate, a sulfur-based additive, and a phosphorus-based additive are combined is known (see Patent Document 2).

  It has also been proposed to use both molybdate and molybdenum oxide in combination with FM agents (friction modifiers) and extreme pressure agents to achieve both wear resistance and low friction under severe conditions. A combination of calcium, molybdic acid and an FM agent or extreme pressure agent is disclosed (see Patent Document 3).

JP 2000-320563 A JP 2002-020776 A JP 2000-053989 A

  However, the above-described conventional general constant velocity universal joint grease is merely a single type uniformly used for all sliding portions of the constant velocity universal joint.

  That is, as shown in FIG. 2, the sliding portion in the constant velocity universal joint includes (i) track groove 6-roller 9, (ii) needle roller 10—inner diameter surface of roller 9 and needle roller 10—bearing ring. (Iii) the inner diameter surface of the bearing ring 8 and the outer peripheral surface of the leg shaft 2, and the tripod constant velocity universal joint shown in FIGS. When transmitting, the roller unit 7 attached to the elliptical columnar leg shaft reciprocates (swings) in the track groove 6 while tilting (swinging the neck) with respect to the axis of the leg shaft. Part (i) has a sliding motion with rolling, part (ii) has a rolling motion with slight oscillation, and part (iii) has a sliding motion under high contact pressure in a point contact state. do.

  In the use state of the constant velocity universal joint in which such various sliding or rolling friction states occur, there is a problem that it is difficult to obtain the lubrication characteristics suitable for all the lubrication characteristics.

  For this reason, wear due to fretting is likely to occur inside constant velocity universal joints, and flaking is likely to occur at other points, making it difficult to adjust to a lubrication state that can solve all problems at once. It was thought to be.

  Accordingly, an object of the present invention is to solve the above-mentioned problems and reliably prevent wear due to fretting and flaking due to flaking on the friction surface of the tripod type constant velocity universal joint, thereby improving the durability of the tripod having excellent durability. -It is to make a constant velocity universal joint.

  In order to solve the above-mentioned problems, in the present invention, a tripod shaft portion having three leg shafts around the shaft, and a joint shaft portion provided with a cylindrical portion at one end into which the tripod shaft portion can be inserted, Three track grooves extending in the axial direction are formed on the inner peripheral surface of the cylindrical portion, and a bearing ring of a roller unit is fitted on each leg shaft so as to be slidably rotatable. In the tripod type constant velocity universal joint in which the tripod shaft portion is fitted to the tubular portion of the joint shaft portion so as to be guided by the side wall surface of the joint, the first lubricating grease is held between the bearing ring and the roller, and A second lubricating grease is held on the sliding contact surface between the bearing ring and the leg shaft, the sliding contact surface between the roller and the track groove, or both sliding contact surfaces, and the first lubricating grease is increased with a urea compound. And fafner A tripod characterized in that it is a fretting-resistant lubricating grease having an abrasion amount of 15 mg or less in the test (ASTM D4170), and the second lubricating grease is an abrasion-resistant lubricating grease containing an extreme pressure agent or a solid lubricant. The mold was a constant velocity universal joint.

  The tripod type constant velocity universal joint of the present invention constructed as described above is increased with a urea-based compound between the bearing ring and the roller, and has a wear amount of 15 mg or less in a Fafner test (ASTM D4170). Holds lubricating grease and holds wear-resistant lubricating grease containing extreme pressure agent or solid lubricant on the sliding contact surface between the bearing ring and the leg shaft, or the sliding contact surface between the roller and the track groove, or both sliding contact surfaces. By doing so, the lubricating grease having appropriate physical properties is held in the sliding portions having different required effects.

  Therefore, it is possible to reliably prevent wear due to fretting and flaking due to flaking on the friction surface of the tripod type constant velocity universal joint, thereby providing a tripod type constant velocity universal joint with excellent durability.

  As an example of a tripod type constant velocity universal joint applicable to the present invention, the roller unit is a tripod type constant velocity universal joint of a needle roller unit.

To improve the fretting resistance inside the roller unit, the first lubricating grease is a lubricating grease in which a base oil with a base oil viscosity of 10 mm ² / s or less at 100 ° C. is increased. It is preferable to use a joint, and it is also preferable that the first lubricating grease is a lubricating grease having a consistency of 285 or more.

  In order to more reliably improve the wear resistance of the sliding contact surface between the bearing ring and the leg shaft or the sliding contact surface between the roller and the track groove, the second lubricating grease is an aliphatic or alicyclic group. Alternatively, a tripod type constant velocity universal joint made of a lubricating grease increased with a urea compound belonging to any of aromatic groups is preferable.

  According to the present invention, a first predetermined lubricating grease is held between a bearing ring and a roller of a roller unit of a tripod type constant velocity universal joint, and a sliding contact surface between the bearing ring and a leg shaft or a roller and a track groove are provided. By holding the second predetermined lubricating grease on the sliding surface or both sliding surfaces, it is possible to reliably prevent abrasion due to fretting or flaking on the friction surface, and to have excellent durability. There is an advantage that it becomes a type constant velocity universal joint.

  As shown in FIGS. 1 to 4, the tripod constant velocity universal joint used in the embodiment of the present invention includes a tripod shaft portion 3 having three leg shafts 2 around a shaft 1 and the tripod shaft portion 3 inserted therein. It consists of a joint shaft portion 5 provided with a possible tubular portion 4 at one end. Then, three track grooves 6 extending in the axial direction are formed on the inner peripheral surface of the cylindrical portion 4, and the inner diameter is set so that the bearing rings 8 of the roller unit 7 can slide and rotate on the three leg shafts 2. And the tripod shaft portion 3 is fitted to the tubular portion 4 of the joint shaft portion 5 so that the roller 9 of the roller unit 7 is guided by the pair of opposite side wall surfaces of the track groove 6. Yes.

  In the illustrated roller unit 7, a needle roller 10 is interposed between the bearing ring 8 and the roller 9 in a full roller state, but a known cylindrical roller other than the needle roller 10 is used. Even if it is, it can be adopted.

  Also, as shown in FIGS. 2 and 3, the roller unit 7 has a bearing ring 8 fitted on an elliptical columnar leg shaft 2 so as to be slidable and rotatable, so that the outer periphery of the leg shaft 2 and the bearing ring 8 are pointed. Even if a force is applied to try to incline the axis of the roller unit 7 with respect to the axis of the leg shaft 2, the force is obtained by using a cylindrical leg shaft (not shown). It is reduced compared to the speed universal joint, and the posture stability of the roller unit 7 is improved accordingly.

  In addition, the code | symbol 11 in FIG. 1 is a rubber boot, and code | symbols 12 and 12 'are the band-shaped stoppers which stop it.

  In such a tripod type constant velocity universal joint, the first lubricating grease held between the bearing ring 8 and the roller 9 of the roller unit 7 is increased with a urea compound, and Fafner test (ASTM D4170). Then, a fretting-resistant lubricating grease with a wear amount of 15 mg or less is enclosed.

  Urea-based thickeners are obtained by reacting amines and diisocyanates in base oils to precipitate urea compounds in a dispersed state, but greases that have better fretting resistance than metal soap-based thickeners and others. Can be adjusted.

  Examples of the urea thickener in the first lubricating grease used in the present invention include a diurea compound and a polyurea compound, but the type thereof can be used without any particular limitation.

R ¹ NH—CO—NH—R ³ —NH—CO—NHR ²
Wherein R ¹ and R ² are the same or different linear alkyl groups having 4 to 24 carbon atoms or cyclohexyl groups having 6 carbon atoms, and R ³ is an aromatic hydrocarbon group having 6 to 15 carbon atoms. .)

  The diurea compound represented by the above formula can be obtained, for example, by reaction of diisocyanate and monoamine. Examples of the diisocyanate include phenylene diisocyanate, diphenyl diisocyanate, phenyl diisocyanate, diphenylmethane diisocyanate, octadecane diisocyanate, decane diisocyanate, and hexane diisocyanate. Examples of the monoamine include octylamine, dodecylamine, hexadecylamine, octadecylamine, oleylamine, aniline, p-toluidine, cyclohexylamine and the like.

  The polyurea compound can be obtained, for example, by reacting diisocyanate with a monoamine or diamine. Examples of the diisocyanate and monoamine include those similar to those used for the production of the diurea compound. Examples of the diamine include ethylenediamine, propanediamine, butanediamine, hexanediamine, octanediamine, phenylenediamine, tolylenediamine, and xylenediamine. Can be mentioned.

  By the way, fretting is a condition where vibration load is applied to the sliding part and it swings with a small amplitude. Is a phenomenon that progresses.

As the preferred conditions other as the first lubricating grease, the base oil may be a mixture of two or more oils, but both are non-ester, 10 mm base oil viscosity at 100 ° C. ² / That is, it is a lubricating grease having a consistency of 285 or more.

  Base oils include commonly used lubricating oils such as paraffinic and naphthenic mineral oils, ether synthetic oils, hydrocarbon synthetic oils, silicone oils, fluorine oils, GPL base oils, or mixtures thereof. However, it is not limited to these.

  Consistency greatly affects fretting resistance. When the grease has a low consistency, that is, the grease has a hard property, it is difficult for the grease to intervene at the interface at the time of fine wear, and the fretting resistance is lowered.

  Next, the second lubricating grease used in the present invention is an abrasion-resistant lubricating grease containing an extreme pressure agent or a solid lubricant.

Regarding the second lubricating grease, the base oil type is not particularly limited, and two or more types may be mixed and used.
As base oils, commonly used lubricating oils such as paraffinic and naphthenic mineral oils, ester synthetic oils, ether synthetic oils, hydrocarbon synthetic oils, silicone oils, fluorine oils, GPL base oils, Or, mixed oils thereof may be mentioned, but the oil is not limited to these. However, mineral oil is preferable in consideration of boot resistance and the like.

Examples of thickeners for the second lubricating grease include soaps such as lithium soap, lithium complex soap, calcium soap, calcium complex soap, aluminum soap and aluminum complex soap, and urea compounds such as diurea compounds and polyurea compounds. Preferably, it is a urea compound. In particular, in the following formula, a diurea compound containing an alkyl group or a cyclohexyl group in R ¹ or R ² is preferable.

R ¹ NH—CO—NH—R ³ —NH—CO—NHR ²
Wherein R ¹ and R ² are the same or different linear alkyl groups having 4 to 24 carbon atoms or cyclohexyl groups having 6 carbon atoms, and R ³ is an aromatic hydrocarbon group having 6 to 15 carbon atoms. .)

  The diurea compound represented by the above formula can be obtained, for example, by reaction of diisocyanate and monoamine. Examples of the diisocyanate include phenylene diisocyanate, diphenyl diisocyanate, phenyl diisocyanate, diphenylmethane diisocyanate, octadecane diisocyanate, decane diisocyanate, and hexane diisocyanate. Examples of the monoamine include octylamine, dodecylamine, hexadecylamine, octadecylamine, oleylamine, aniline, p-toluidine, cyclohexylamine and the like.

  The polyurea compound can be obtained, for example, by reacting diisocyanate with a monoamine or diamine. Examples of the diisocyanate and monoamine include those similar to those used for the production of the diurea compound. Examples of the diamine include ethylenediamine, propanediamine, butanediamine, hexanediamine, octanediamine, phenylenediamine, tolylenediamine, and xylenediamine. Can be mentioned.

  Such first and second lubricating greases include solid lubricants such as molybdenum disulfide and graphite, friction modifiers such as organic molybdenum, amines, fatty acids, and fats and oils to the extent that the effects of the present invention are not impaired. Oil-based agents such as amines, phenol-based antioxidants, petroleum sulfonates, dinonylnaphthalene sulfonates, rust inhibitors such as sorbitan esters, sulfur-based and sulfur-phosphorus-based extreme pressure agents, organic zinc, phosphorus It may contain various additives such as anti-wear agents such as a system, metal deactivators such as benzotriazole and sodium nitrite, and viscosity index improvers such as polymethacrylate and polystyrene.

[Preparation of base grease 1]
A reaction of 60.6 g of diphenylmethane-4,4-diisocyanate, 31.3 g of octylamine and 66.2 g of stearylamine in 2000 g of mineral oil (kinematic viscosity at 100 ° C. of 13.5 mm ² / sec) Base grease 1 was obtained by uniformly dispersing.

[Preparation of base grease 2]
Urea compound produced by reacting 60.6 g of diphenylmethane-4,4′-diisocyanate, 31.3 g of octylamine and 66.2 g of stearylamine in 2000 g of mineral oil (kinematic viscosity at 100 ° C .: 8.9 mm ² / sec) Was uniformly dispersed to obtain a base grease 2.

[Preparation of base grease 3]
Base grease 2 was obtained by uniformly dispersing 150 g of hydroxylithium stearate in 2000 g of mineral oil (kinematic viscosity at 100 ° C .: 8.9 mm ² / sec).

In addition to the above base greases 1 to 3, the additives formulated in the examples and comparative examples are listed as follows.
1) Melamine cyanurate (Mitsubishi Chemical Corporation)
2) Molybdenum dithiocarbamate (Asahi Denka Kogyo Co., Ltd .: SakuraLube 600)
3) Molybdenum dithiocarbamate (Asahi Denka Kogyo Co., Ltd .: SakuraLube 100)
4) Zinc dithiophosphate (Asahi Denka Kogyo Co., Ltd .: Kikurobu 112)
5) Molybdenum disulfide (manufactured by CLIMAX MOLYBDENUM: average particle size 0.45 μm)

[Examples 1 to 5, Comparative Examples 1 to 4]
The compounds obtained by blending the base greases 1 to 3 and additives prepared as described above in the proportions shown in Table 1 were mixed in a three-stage roll mill, and JIS consistency No. 1 was obtained. The grease for a constant velocity universal joint was obtained by adjusting to 1 grease (consistency: 310 to 340). The obtained grease is applied to a predetermined portion of the tripod type constant velocity universal joint shown in Table 1 (between the bearing ring and the roller of the roller unit, the sliding contact surface between the bearing ring and the leg shaft, and the sliding contact between the roller and the track groove. The tripod type constant velocity universal joints of Examples 1 to 5 and Comparative Examples 1 to 4 (manufactured by NTN Corporation: PTJ having the structure shown in FIGS. 1 to 4) were obtained.

  When the obtained tripod type constant velocity universal joint or special mention was made, grease was sealed in a test bearing and the following tests were conducted. The results are also shown in Table 1.

<Faffner test (ASTM D4170)>
The test conditions to be noted are as follows. Test bearing: 51204J (manufactured by NTN), grease amount: 1.0 ± 0.1 g, test time: 22 hours, rocking angle: 12 deg, frequency: 30 Hz, load: 2450 N, test temperature: room temperature, evaluation item: test Rear bearing wear: mg,

<Induced thrust test>
The tripod type constant velocity universal joints of Examples 1 to 5 and Comparative Examples 1 to 4 (manufactured by NTN having the structure shown in FIGS. 1 to 4: PTJ) were adjusted to an operating angle (joint angle) of 4 ° or 10 °, In each case, when a torque of 392 N-m was applied and rotated for 15 minutes at a rotational speed of 150 rpm, the force generated in the axial direction was measured as the induced thrust force. The evaluation standard of the induced thrust force is expressed as a ratio (%) of the induced thrust when the initial performance is set to 100 with reference to Comparative Example 4. For example, it can be evaluated that a tripod type constant velocity universal joint having an induced thrust ratio of less than 65% is excellent in low vibration.

<Durability test>
The tripod type constant velocity universal joints of Examples 1 to 5 and Comparative Examples 1 to 4 (manufactured by NTN having the structure shown in FIGS. 1 to 4: PTJ) have an operating angle (joint angle) of 0 to 10 ° at a constant cycle. When the torque of 774 N-m was applied and rotated at a rotational speed of 240 rpm for 300 hours, the wear depth of the journal part (leg shaft) was measured, and after this durability test, The presence or absence of flaking was examined. The result was a two-step evaluation with and without. In Comparative Example 4, the amount of wear was large, and rotation was impossible in a test time of 200 hours, and the test was stopped.

<Comprehensive evaluation>
In the durability test, the tripod type constant velocity universal joint with no flaking in the roller unit and the wear depth of the leg shaft being 30 μm or less was evaluated as having excellent durability. Those not corresponding to this evaluation were evaluated as unusable and indicated by “x” in the table.

Cross section of tripod type constant velocity universal joint II-II sectional view of FIG. Sectional view taken along line III-III in FIG. Sectional view showing operating state of tripod type constant velocity universal joint at operating angle θ

Explanation of symbols

1 shaft 2 leg shaft 3 tripod shaft portion 4 tubular portion 5 joint shaft portion 6 track groove 7 roller unit 8 bearing ring 9 roller 10 needle roller

Claims (4)

It consists of a tripod shaft portion having three leg shafts around the shaft and a joint shaft portion provided with a cylindrical portion into which the tripod shaft portion can be inserted at one end, and is axially disposed on the inner peripheral surface of the cylindrical portion. Are formed on each leg shaft, and a roller unit is provided on each leg shaft. The roller unit is slidably in contact with the outer periphery of the leg shaft and is rotatably supported. The tripod shaft portion is fitted to the tubular portion of the joint shaft portion so that the roller of the roller unit is guided to the side wall surface of the track groove. In tripod type constant velocity universal joints,
The fretting-resistant first lubricating grease is held between the bearing ring and the roller of the roller unit, and the contact surface between the bearing ring and the leg shaft or the contact surface between the roller and the track groove or both contact surfaces A second lubricating grease having wear resistance is retained, and the first lubricating grease is enriched with a urea compound, and is a fretting resistant lubricating grease having a wear amount of 15 mg or less in a Fafner test (ASTM D4170). A tripod type constant velocity universal joint characterized in that the second lubricating grease is an abrasion-resistant lubricating grease containing an extreme pressure agent or a solid lubricant.   The tripod type constant velocity universal joint according to claim 1, wherein the roller unit is a full-roller type roller unit in which rolling elements are needle rollers. The tripod type constant velocity universal joint according to claim 1 or 2, wherein the first lubricating grease is a lubricating grease obtained by increasing a base oil having a base oil viscosity of 10 mm ² / s or less at 100 ° C.   The tripod type constant velocity universal joint according to any one of claims 1 to 3, wherein the second lubricating grease is a lubricating grease increased with a urea compound belonging to any of aliphatic, alicyclic or aromatic. .

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