JPH08835U - Constant velocity universal joint - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To enable a constant velocity universal joint to be used under severe conditions (high speed, high load, high angle) without seizure or wear. SOLUTION: A surface treatment layer having a surface hardness of HRC63 or higher is provided at at least one of contact parts of constituent parts. As such a surface treatment layer, carbides such as titanium carbide (TiC) and vanadium carbide (VC), cubic boron nitride (CBN), titanium nitride (TiN), silicon nitride (Si ₃ N ₄ ), etc. And a metal composite such as molybdenum (Mo) or tungsten (W).

Description

[Detailed description of the device]

[0001]

[Technical field to which the device belongs]

 The present invention relates to a constant velocity universal joint used for power transmission in automobiles and various industrial machines.

[0002]

[Prior art]

 There are various types of constant velocity universal joints, but FIG. 2 shows a type that can make angular displacement and relative axial displacement between a drive shaft and a driven shaft. (10), inner member (20), ball (30) and cage (40). The outer member (10) and the inner member (20) are splined to the drive shaft or the driven shaft, respectively. The outer member (10) has an axial guide groove (11) on the inner peripheral surface (12), and the inner member (20) has an axial guide groove (21) on the outer peripheral surface (22). To do. These guide grooves (11, 21) form a pair, and a ball (30) held by a retainer (40) is interposed in each pair of guide grooves (11, 21) to transmit torque.

As shown enlarged in FIG. 3 (A), the cage (40) is located between the outer member (10) and the inner member (20), and the outer member (44) has an outer member (44). It contacts the inner peripheral surface (12) of (10) and contacts the outer peripheral surface (22) of the inner member (20) at the inner peripheral surface (42).

Due to such a structure, in this type of constant velocity universal joint, members such as the inner member (20), the retainer (40), and the ball (30) are different from the outer member (10). It can move relative to the axial direction. When an operating angle is applied to the joint and a rotational force is applied while sliding in the axial direction, relative slip occurs between the members of the joint. Therefore, lubrication is performed with oils and fats such as grease.

Particularly, in a constant velocity universal joint for automobiles, structural measures such as those illustrated in FIGS. 3B and 3C have been made as measures against so-called NVH of vehicles. That is, they both provide an axial clearance between the inner member (10) and the retainer (40), and a small amount between the pocket (46) of the retainer (40) and the ball (30). It is intended to ensure clearance (Lc> dw) and allow the ball (30) to roll, thereby achieving low slide resistance of the joint. For example, in the case of FIG. 3 (B), the inner peripheral surface of the cage (40) is made larger than the outer peripheral surface of the inner member (20) (R c> Ri), and in the case of FIG. 3 (C), The inner peripheral surface of the retainer (40) is formed by a concave spherical surface having a center of curvature at a point offset by an equal distance in the axial direction from the width center of the inner member (20) and a cylindrical surface at the central portion.

[0006]

[Problems to be solved by the device]

 The axial relative movement is allowed by sliding or sliding between the outer member (10) and the retainer (40) or the ball (30). However, since the contact state between the outer peripheral surface (44) of the cage (40) and the inner peripheral surface (12) of the outer member (10) is line contact along the annular contact line, the cage (40) There is a problem that the outer peripheral surface and the inner peripheral surface (12) of the outer member (10) are easily worn. Further, the cage (40) has a plurality of pockets (46), and these pockets (46) penetrate the cage (40) in the radial direction, and moreover, a predetermined tolerance angle is given. A clearance is provided in the circumferential direction between the ball (30) and the ball (30). Therefore, the lubricant is easily removed by the edge portion of the pocket (46), and the lubrication between the outer member (10) and the inner surface (12) is difficult to be maintained. Furthermore, since the cage (40) can rotate independently in the circumferential direction at any tolerance angle within the allowable range, the contact position with the inner peripheral surface (12) of the outer member (10) becomes unstable. . It is considered that the above-mentioned points increase the slide resistance and induced thrust of the joint and cause variations. Moreover, these are unfavorable factors for the NVH characteristics of vehicles in the case of constant velocity universal joints used in automobiles.

The induced thrust and slide resistance due to the internal friction of the constant velocity universal joint are related to structural improvements such as those shown in FIG. 3 (B) and FIG. 3 (C), adoption of low μ grease, and surface resistance. Although the friction coefficient has been reduced by treatment, the effect of low-μ grease seems to have almost reached its limit. In other words, unless the grease's ability to intervene on the friction surface becomes better than it is now, no further effect will appear.

Therefore, in order to further reduce the induced thrust and the slide resistance due to the internal friction of the constant velocity universal joint, it is necessary to reduce the internal friction of the constant velocity universal joint. An object of the present invention is to enable a constant velocity universal joint to be used under severe conditions (high speed, high load, high angle) without seizure or wear.

[0009]

[Means for Solving the Problems]

 In this invention, a surface treatment layer having a hardness of HRC63 or more, which is made of a carbide, a nitride, or a metal composite such as molybdenum or tungsten, is provided in at least one of contact portions of components of a constant velocity universal joint. Further, the rolling elements can be made of ceramics. The presence of the hardened and high-melting surface hardened layer improves the wear resistance and seizure resistance of the inner corner contact portion of the joint.

[0010]

[Embodiment of device]

 Embodiments of the present invention will be described below with reference to the drawings. The constant velocity universal joint of the present invention is substantially the same as that shown in FIG. 2 as far as the basic constituent elements are concerned. Therefore, substantially the same members or portions are designated by the same reference numerals throughout the drawings. Therefore, duplicate description will be omitted. -FIG. 1 (A) shows a cage (40) made of a sintered oil-impregnated alloy. In this case, naturally, the outer peripheral surface (44) and the inner peripheral surface (42) of the cage (40) are also formed of the sintered oil-impregnated alloy. As the oil to be impregnated, the base oil of grease that is enclosed in the constant velocity universal joint is suitable. The oil impregnated in the sintered oil-impregnated alloy gradually exudes to the surface of the cage (40) during use of the constant velocity universal joint. As a result, an oil film is always formed between the retainer (40) and the outer member (10) and the inner member (20), so that the retainer (40) does not move even when vibration acts on the joint. Absorbs this by moving with low friction. Therefore, the induced thrust is also suppressed.

Further, the case of the cage (40) made of a porous ceramic material is also as shown in FIG. 1 (A). The porous ceramic material impregnated with oils and fats exhibits self-lubricating performance similar to the above-mentioned sintered oil-impregnated alloy, and is retained between the cage (40) and the outer member (10) and the inner member (20). Reduce the frictional resistance of.

As shown in FIG. 1 (A), when the entire cage is made of a sintered oil-impregnated alloy or a porous ceramic material, the cage pocket of the cage is caused by the wear resistance of these materials. It is possible to prevent the backlash between the ball and the ball from increasing, which is also advantageous in preventing hitting sound.

FIG. 1 (B) shows an embodiment in which a solid lubricant coating layer (47) is formed on the inner and outer peripheral surfaces of a steel cage (40). As the solid lubricant, molybdenum disulfide, lead, silver, gold or the like can be appropriately selected and used. The coating layer (47) may be provided on the entire surface of the retainer (40) as shown in the figure, or may be provided only on the inner and outer peripheral surfaces, that is, the sliding surface as shown in FIG. 1 (C).

In the embodiment shown in FIG. 1 (C), a steel coating (48) is formed on the inner and outer peripheral surfaces of a cage (40) made of steel. Also in this case, the coating layer (48) may be provided on the entire surface of the retainer (40) as shown in FIG. 1 (B).

By the way, in constant velocity universal joints for propeller shafts and drive shafts of automobiles, components such as outer members, inner members and cages other than rolling elements such as balls and rollers are mainly used. It is common to use by carburizing or induction hardening / tempering the contact area. However, this gives a surface hardness of only up to about HRC63. Therefore, a surface hardness of HRC63 or higher is required in order to be able to use it under more severe conditions (high speed, high load, high angle) without causing seizure or wear.

Therefore, a surface treatment layer having a surface hardness of HRC63 or higher is provided in at least one of the contact parts of the above-mentioned components. As such a surface treatment layer, titanium carbide (TiC), vanadium carbide (VC) and other carbides, cubic boron nitride (CBN), titanium nitride (TiN), silicon nitride (Si ₃ N ₄ ) And a metal composite such as molybdenum (Mo) or tungsten (W). These surface-treated layers can be provided by a method such as CVD, PVD molten salt dipping, or thermal spraying.

The surface-treated layer thus formed has a hardness of HRC63 or higher, is an inert layer having a high melting point and hardly adhering, and therefore wear resistance and seizure resistance of each contact portion in the joint. Improved performance, improved durability and expanded range of use. For rolling elements such as balls or rollers, from the viewpoint of the strength of the surface layer and the uniformity of the film, an effect equivalent to that of providing the surface treatment layer is obtained by using ceramics instead of adopting the surface treatment. Obtainable.

[0018]

[Effect of device]

 As described above, according to this invention, since the surface treatment layer having high hardness and high melting point is provided, the wear resistance and the seizure resistance are improved, and it is possible to use it under more severe conditions. Effects such as improvement of durability and expansion of usage range can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of a cage.

FIG. 2 is a sectional view of a constant velocity universal joint.

FIG. 3 is a partially enlarged sectional view of a constant velocity universal joint.

[Explanation of symbols]

 10: Outer member 20: Inner member 30: Ball (rolling element) 40: Cage 42: Inner surface 44: Outer surface 47: Coating layer (solid lubricant) 48: Coating layer (ceramics)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location C23C 16/30 30/00 BC (72) Creator Fumio Hoshikawa 2-1 Fujimi-cho, Iwata-shi, Shizuoka -3 (72) Creator Toru Yamase 235-14 Kusazaki, Iwata-shi, Shizuoka Prefecture (72) Creator Kazuhiko Yoshida 1905-37 Hirooka, Fukuroi-shi, Shizuoka Prefecture

Claims (2)

[Scope of utility model registration request] 1. An outer member having an axial guide groove formed on its inner peripheral surface, an inner member having an axial guide groove formed on its outer peripheral surface, a guide groove of the outer member and a guide member of the inner member. A rolling element interposed between the rolling element and the guide groove to transmit torque, and a cage for holding the rolling element between the inner peripheral surface of the outer member and the outer peripheral surface of the inner member. At least one
A constant velocity universal joint in which a surface treatment layer of hardness HRC63 or higher made of a metal compound such as carbide, nitride or molybdenum or tungsten is provided in a place. 2. The constant velocity universal joint according to claim 1, wherein the rolling element is made of ceramics.