JPS6112129B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in sliding spline joints used in vehicle drive systems, particularly automobiles.

In automobiles, this type of sliding spline joint consists of a sleeve with a number of spline grooves cut therein, and a spline shaft with a number of splines cut in it that is slidably received in the sleeve and meshed with the spline grooves. Therefore, it has been used in the drive system for transmitting the power of the prime mover to the wheel shaft, that is, the propeller shaft.

When used in propeller shafts in this way, the sliding spline joint must have low frictional resistance against relative sliding in the axial direction, sufficient resistance to impact loads during torque transmission, and Also, in the direction of rotation, there is little play between the sleeve and the spline shaft, and when transmitting torque,
It is required that no noise is generated and that the initial break-in is good.

Therefore, in the past, in order to reduce the sliding friction resistance between the sleeve and the spline shaft, spline joints were manufactured by applying anti-friction surface treatment to the splines of the spline shaft, or by applying an anti-friction surface treatment to the splines of the spline shaft. As described above, the splines of the spline shaft have been coated with a thin nylon film in order to reduce the sliding friction resistance and absorb the impact load during torque transmission.

However, in the former method, even though the sliding friction resistance of the sliding spline joint is greatly reduced, it is difficult to absorb the impact load during torque transmission, and
In the latter method, although the sliding friction resistance of the sliding spline joint is reduced and the impact load during torque transmission is absorbed, the nylon thin film is thicker than the metal coating, so the spline shaft and the spline joint are
A relatively large fitting gap is required between the sleeve and the spline shaft.
The radial and circumferential gaps between the spline shaft and the sleeve become larger, and as a result, even though the rotational impact load is absorbed during torque transmission, the spline shaft and the sleeve have a relatively large sliding force. When a large torque is transmitted in a state where the shaft is moved to Therefore, deviation occurs between the spline shaft and the spline sleeve, making it difficult to smoothly reciprocate sliding fit between the spline shaft and the spline sleeve. , it was difficult to use it for a long time.

Furthermore, Japanese Utility Model Publication No. 45-31449 discloses a spline drive spindle that prevents eccentricity. That is, the drive spindle has a cylindrical sleeve at the inlet end and inner part of the female shaft into which the splined male shaft is fitted, and there is a space between the splined male shaft and these sleeves on the outer diameter. It is something that makes you However, since these sleeves are formed inside the female shaft, machining the inner surface of the sleeve and machining the inner surface of the female shaft to fit the sleeve is required to machining the outer peripheral surface of the spline male shaft. It is difficult to fit the spline male shaft and its female shaft, and good initial fitting cannot be expected.

As such, it has been difficult for these conventional methods to satisfy the requirements placed on sliding spline joints mentioned above.

The object of the present invention is to reduce sliding friction resistance, sufficiently absorb shock loads during torque transmission, and to reduce frictional resistance in the drive system of automobiles, that is, propeller shafts. It reduces play between the spline shaft and the sleeve in the direction, prevents deviation between the spline shaft and the sleeve when large torque is transmitted, and ensures smooth reciprocation between the spline shaft and the sleeve. To provide a sliding spline joint that enables sliding, improves initial fitting, prevents noise generation, and improves durability.

In order to solve these problems, the sliding spline joint of the present invention has a large diameter part on the tip side and a small diameter part on the base side, and has a spline shaft in which a plurality of splines are formed on the outer surface of the large diameter part. The spline shaft is telescoped inside,
and to determine the large diameter and small diameter inner surfaces,
A sleeve having a plurality of spline grooves formed on the inner surface thereof corresponding to the splines, and a sleeve formed in the small diameter part of the spline shaft and appropriately spaced from the large diameter part in the length direction of the spline shaft, and When the shaft is fitted into the sleeve, a contact land is fitted onto the small-diameter inner surface of the sleeve, and a pair of reliefs extending in the length direction of the spline groove are formed on both sides of the bottom of each spline groove. A thin synthetic resin coating layer covers the spline part formed on the large diameter part of the spline shaft so as to expose the groove and the top surface of the spline, and a thin low-friction layer coats the top surface of the spline. It is composed of metal.

Hereinafter, preferred specific examples of the sliding spline joint according to the present invention will be described with reference to the drawings.

Figures 1 to 3 show an embodiment 10 of the sliding spline joint of the present invention applied to a propeller shaft 30 of a truck.

The propeller shaft 30 is connected to a transmission (not shown) connected to an engine (not shown) via a clutch (not shown) and a rear wheel (not shown) via a rear axle (not shown). A differential gear (not shown) that transmits power to the transmission and the differential gear (not shown) that transmits power to the rear axle. A sliding spline joint 10 is used in the transmission, and the sliding spline joint 10 is arranged on the transmission side.

The sliding spline joint 10 includes a spline shaft 11 integrally attached to the transmission end of the propeller shaft 30, a sleeve 12 that telescopically receives the spline shaft 11 therein, and an oil - Includes a seal (not shown) and an oil seal retainer (not shown).

The spline shaft 11 has a large diameter portion 13 on the tip side.
The base side thereof is formed into a small diameter portion 14, and a large number of splines 15 are formed on the outside of the large diameter portion 13, and the spline shaft 11 is appropriately separated from the large diameter portion 13 in the longitudinal direction of the spline shaft 11. Then, the contact land 16 is stepped on the outside of the small diameter portion 14, and when the spline shaft 11 is fitted into the sleeve 12, the contact land 16 is stepped.
6 is fitted onto the small-diameter inner surface of the sleeve 12, and the contact surface of the spline shaft 11 against the sleeve 12 in the axial direction is lengthened.

The outer diameter of the contact land 16 is determined in relation to the inner diameter of the sleeve 12, in particular the outer diameter of the contact land 16 and the inner surface 17 of the sleeve 12.
The gap between the two is determined to be extremely small.

Further, the sleeve 12 has a large number of spline grooves 18 formed inside thereof corresponding to the splines 15, and allows the spline shaft 11 to be received telescopically inside the sleeve 12 in the axial direction. A yoke 19 for the joint is integrally formed.

In this way, the sliding spline joint 10 is constructed with large diameter fitting and small diameter fitting, and in particular, considering that the meshing accuracy of the teeth is naturally limited by the processing machine, it is designed to have good initial break-in. , and a relatively soft nylon thin film 21 is coated on the tooth surface to reasonably reduce sliding frictional resistance.

That is, the spline shaft 11, which is one component of the sliding spline joint 10, is connected to each spline 1.
The large diameter portion 13 is coated with a thin film 21 made of nylon so as to expose the top surface 20 of the large diameter portion 5 .

This can also be understood from Figure 2.

The nylon thin film 21 is coated on the large diameter portion 13 in a conventional manner and is integrally connected or continuous at both ends of each spline 15, in other words, at both ends of the large diameter portion 13. but,
As such, the connection portions that are integrally connected at both ends are not shown.

Furthermore, the top surface 20 of each spline 15 exposed from the nylon thin film 21 constitutes one first contact surface, and is coated with a thin film 22 made of a low-friction metal.

In detail, the coating of the low friction metal film 22 is applied to the top surface 20 of the spline 15 by, for example, a conventional phosphate coating. That is, a saturated solution of ferrous phosphate with manganese dioxide added is heated to about 95°C, the spline shaft 11 coated with the nylon thin film 21 is placed in the solution, and the top surface 20 of the spline 15 is coated with phosphoric acid. A coating of manganese is produced, thus coating the top surface 20 of the spline 15 with a thin film of iron phosphate and manganese phosphate.
Coating.

In this way, since the tooth surfaces and tooth bottoms of the spline shaft 11 are coated with the nylon thin film 21, it is extremely easy to apply the phosphate coating only to the top surface 20 of the spline 15 on the spline shaft 11. Become.

Further, the sleeve 12 which is the other component of the sliding spline joint 10 has the bottom surface 23 of each spline groove 18 as the other first contact surface, and the bottom surface 23 of each spline groove 18 as the top surface of each spline 15.
It is configured to be complementary to 0. Moreover, the bottom surface 23 of each spline groove 18 has a high precision.
It is smoothly broached to make the gap between the bottom surface 23 and the top surface 20 of the corresponding spline 15 extremely small. Further, the bottom surface 23 of each spline groove 18 is broached with a pair of relief grooves 24 on both sides, so that the processing accuracy of the bottom surface itself can be increased.

Further, the sleeve 12 has its inner surface 17 as a contact land 16, that is, a second contact surface on the one hand and a second contact surface on the other hand.

Since the sliding spline joint 10 is configured as described above, when used in a truck, the nylon thin film, ie, the thin nylon coating layer 21 reduces the sliding frictional resistance between the spline shaft 11 and the sleeve 12. , during torque transmission, absorbs the impact load between the spline shaft 11 and the sleeve 12 in the rotational direction, and suppresses the generation of noise.

Furthermore, the bottom surface 23 of the spline groove 18 is smoothly broached with high precision, and the top surface 20 of the spline 15 is coated with a low-friction metal coating, that is, a thin low-friction metal layer 22. The sliding friction resistance between the shaft 11 and the sleeve 12 is reduced,
In addition, since the abutment surface for the sleeve 12 is formed by the large diameter portion 13 and the small diameter portion 14 of the spline shaft 11, the spline shaft 11 in the axial direction
The backlash between the sleeve 12 and the sleeve 12 is extremely small, which not only suppresses the generation of noise, but also suppresses uneven contact between the meshing parts, which has an extremely positive effect on the life of the nylon thin film 21.

From the above, compared to the spline joints that have already been proposed and used, the sliding spline joint of the present invention has no spline shaft in the large diameter part on the tip side and the small diameter part in the base side. ,
A plurality of splines are formed on the outer surface of the large diameter portion, and a plurality of splines corresponding to the splines are formed such that the sleeve telescopically receives the spline shaft therein and defines a large diameter and a small diameter inner surface. A spline groove is formed on the inner surface of the spline shaft, a contact land is formed in the small diameter part of the spline shaft, appropriately spaced from the large diameter part in the longitudinal direction of the spline shaft, and the spline shaft is fitted into the sleeve. When mated, the small-diameter inner surface of the sleeve is fitted, a pair of relief grooves are formed on both sides of the bottom of each spline groove, extending along the length of the spline groove, and a thin synthetic resin coating layer is formed on each side of the bottom surface of each spline groove. , the spline portion formed on the large diameter portion of the spline shaft is covered so that the top surface of the spline is exposed, and a thin low-friction metal layer is coated on the top surface of the spline. In the sliding spline joint of the present invention, the large diameter portion of the spline shaft that becomes the top surface of the spline, the outer surface of the contact land, the inner surface of the sleeve, and the bottom surface of the spline groove with the pair of relief grooves are In addition, the thin, low-friction metal layer covering the top surface of the spline allows for high-precision finishing to be applied with great ease, and the thin, low-friction metal layer covering the top surface of the spline provides a smooth surface between the top surface of the spline and the bottom surface of the spline groove. The gap between the outer surface of the contact land and the inner surface of the sleeve becomes extremely small, and in this way, the spline shaft and the sleeve are aligned in large diameter and small diameter, in other words, the top surface of the spline and the spline groove are aligned. An outer diameter contact is formed between the bottom surface of the sleeve and an inner diameter contact between the inner surface of the sleeve and the outer surface of the contact land. Rattling and eccentricity are prevented, vibration and noise due to rattling and eccentricity are prevented during torque transmission, and in particular, the spline shaft is slidably pulled out relatively largely from the sleeve. In this state, when a large torque is transmitted, axial deviation between the spline shaft and the sleeve is prevented, and the thin low-friction metal layer covering the top surface of the spline prevents the spline shaft from shifting between the sleeve and the spline shaft. The sliding friction resistance between the sleeve and the sleeve is reduced, and the thin synthetic resin coating layer that covers the spline portion exposes the top surface of the spline. The shock load between the spline shaft and the sleeve is effectively absorbed, noise generation is suppressed, uneven contact of the meshing part is suppressed, and a smooth reciprocating sliding fit between the spline shaft and the sleeve is achieved. Damage to its synthetic resin coating layer and low-friction metal layer is prevented, and it is particularly good at transmitting large torques, ensuring smooth reciprocating sliding between the spline shaft and the sleeve even when such large torques are transmitted. In particular, when such a large torque is transmitted, the synthetic resin coating layer is elastically deformed and protrudes outward from the spline top surface on both sides of the spline top surface.
The protruding portion of the synthetic resin coating layer is accommodated in the relief groove, and is prevented from wear and tear due to relative reciprocating sliding between the spline and the sleeve, and the synthetic resin coating layer is prevented from peeling off from the protruding portion. Accordingly, the durability of the synthetic resin coating layer is greatly improved, allowing long-term use and improving practicality.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of a truck propeller shaft using a sliding spline joint according to the present invention, and FIG. 2 is a partial sectional view taken along line 2-2 in FIG. Figure 3 shows 3- in Figure 1.
FIG. 3 is a partial cross-sectional view taken along line 3; 10...Sliding spline joint, 11...Spline shaft, 12...Sleeve, 13...Large diameter portion,
14...Small diameter portion, 15...Spline, 16...
... Hit land, 17 ... Inner surface, 18 ... Spline groove, 20 ... Top surface, 21 ... Thin film made of nylon, 22 ... Thin film made of low friction metal, 23 ...
Bottom surface, 24...Escape groove.

Claims (1)

[Scope of Claims] 1. A spline shaft with a large diameter portion on the tip side and a small diameter portion on the base side, with a plurality of splines formed on the outer surface of the large diameter portion, and a telescope inside the spline shaft. a sleeve having a plurality of spline grooves formed on the inner surface thereof corresponding to the splines so as to receive the inner surface of the sleeve and determine the inner surface of the large diameter and the small diameter; a contact land which is formed in the small diameter portion of the sleeve and is appropriately spaced apart from the spline groove, and which fits into the small diameter inner surface of the sleeve when the spline shaft is fitted into the sleeve; A thin film that covers the spline portion formed on the large diameter portion of the spline shaft is extended to expose a pair of relief grooves formed on both sides of the bottom surface of each spline groove and the top surface of the spline. A sliding spline joint that includes a synthetic resin coating layer and a thin low-friction metal layer that coats the top surface of each spline.