JPS5855365B2 - universal joint - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a universal joint, and particularly to an improvement in a lubricating oil retaining mechanism of a universal joint using a cruciform shaft.

Conventional universal joints have a grease injection hole in the center of the cruciform shaft, and grease is injected under pressure through this injection hole.

The press-fitted grease reaches the oil reservoir at the end of each shaft through the oil supply hole extending radially toward the center of each shaft, and lubricates the bearing at the end of the cruciform shaft and the needle roller in the bearing cap.

Grease is difficult to flow at room temperature, but when the universal joint is in operation, it becomes completely liquid as the temperature rises.

The universal joint rotates at high speed during operation, and its temperature rises significantly due to frictional heat, reaching approximately 200°C.

Therefore, the internal grease is in a liquid state with low viscosity.

In such a state, while the universal joint is rotating, liquid grease is sent to the shaft end by centrifugal force, and the pressure causes it to gradually seep out from the oil seal.

Thus, when the amount of injected grease is reduced, various problems arise.

The main lubrication drawbacks of conventional universal joints under such conditions of use are as follows.

That is, when the universal joint is stopped, the grease in the shaft end located at the top of the cross shape is in liquid form, so it falls under its own weight, creating voids, and becomes highly viscous as the temperature decreases.

Therefore, when the universal joint is restarted, a gap remains at this location and oil runs out, causing metal-to-metal friction between mechanical parts, causing wear or seizure.

Various measures have been considered in the past to deal with wear and tear caused by lack of oil.

As one measure against this, the applicant has proposed a lubricant protection device that first installs a plunger in the oil supply hole, and when the oil supply pressure decreases, the plunger is pressed by the action of a spring to close the oil supply hole and prevent oil from running out due to oil dripping. did.

(Japanese Patent Application No. 53-150028) An oil retaining member having a substantially W-shaped cross section is provided on each shaft member of the universal joint, and a one-way check valve is provided in the center to prevent the above-mentioned oil leakage. A device has also been proposed (Japanese Patent Publication No. 49-4090).

Each of these devices is more effective than the old ones in terms of falling.

However, it is an object of the present invention to provide a simpler and more effective device.

More specifically, an object of the present invention is to realize a device that satisfies the following points.

(1) Control the amount of grease supplied to the shaft end due to centrifugal force to an appropriate amount.

This suppresses the wear and tear of the grease itself.

(2) Filters out metal powder and other foreign substances contained in or mixed in the grease to prevent poor wear.

(3) Grease is held so as to prevent the grease from dripping back to the center when the motor is stopped, and the lubricating action during driving is started as smoothly as possible.

The present invention remotely addresses each of the above-mentioned problems by providing an oil controller that is more flexible than porous plastic material.

The present invention will be explained below with reference to the drawings.

The drawing shows a universal joint, with a cross-shaped shaft 2, a bearing cap 6, a thrust washer 8, and a needle roller 1.
8. A universal joint is constructed by combining the oil seals 20.

This cruciform shaft 2 includes four shaft portions 4, and the yoke, spline shaft, etc. that are combined with these equiaxed portions are well known and are therefore omitted from illustration.

The cross-shaped shaft 2 shown in the drawing has shaft portions 4 that intersect at right angles, but only one of them is shown as a cross section.

A thrust washer 8 made of a wear-resistant plastic material, for example Delrin #100, is provided between the shaft portion 4 and a bearing cap 6 that fits over the shaft end 7.

Although the thrust washer 8 may not be provided, if the thrust washer 8 is provided, together with the action of the oil controller 10, metal contact between the shaft portion 4 and the bearing cap 6 is prevented, and wear can be further prevented. .

Reference numeral 16 designates the same grease injection nipple as in the past, and the injected grease reaches the oil reservoir 14 through the oil supply hole 12 extending in all directions, and is then delivered to the above-mentioned thrust washer 8 and the needle roller located on the side and center side. Lubricate 18.

Reference numeral 20 indicates an oil seal, which is designed to prevent oil leakage.

In the present invention, an oil controller 10 in the shape of a cylindrical container made of a porous plastic material, for example, polypropylene (trade name: DERN #100) is disposed within the oil reservoir 14.

The oil controller 10 is shown in cross section in the drawings.

The head can be spherical as shown in the figure, and is disposed in the oil reservoir 14 so as to be in contact with the side wall with the head facing the inner rotation center.

The pore diameter of the porous plastic material used for the oil controller 10 was preferably 100 μm, but
A similar effect was obtained with a thickness of up to 300 μm.

However, it has been confirmed through experiments that a thickness of less than 10 μm or more than 500 μm is inconvenient.

The universal joint of the present invention is constructed as described above.

When grease is injected from the grease injection nipple 16, the grease fills the oil supply hole 12, passes through the hole of the porous oil controller 10 due to pressure, reaches the oil sump 14, and the thrust washer 8 and needle roller 18 as described above. Lubricate each part.

Now, when the universal joint is in operation, the temperature reaches a high temperature as mentioned above, and the grease becomes completely liquid. However, if the porous oil controller 10 as mentioned above is provided according to the present invention, the following effects can be obtained. .

([) The supply of grease to the shaft end is controlled by centrifugal force, and the appropriate amount is supplied.

Therefore, oil loss itself is reduced.

(11) The fluid resistance of the oil controller holds the grease so that it does not return to the center when the system stops, and provides smooth lubrication when restarting.

011) Even if foreign matter is mixed in the grease, it is filtered out by the filter action, reducing wear and tear on lubricated parts.

According to the present invention, the following effects can be obtained.
This was confirmed by experiment.

In the past, the lubricating effect of grease was maintained for approximately 20,000 km after one application of grease.

On the other hand, the vehicle that was improved using the prior art described above was improved by about 60,000 km.

However, according to the present invention, 10% of
It has been confirmed that grease can be retained for up to 10,000 km.

The spherical structure of the head has the effect of increasing strength and filtration area.

BRIEF DESCRIPTION OF THE DRAWINGS The drawing is a partial cross-sectional view of the universal joint of the present invention. 2...cruciform shaft, 4...shaft part, 6...
...Bearing cap, 7...Shaft end of shaft portion, 8...Thrust washer, 10...
Oil controller, 12... Oil supply hole, 14.
... Oil reservoir, 16 ... Grease supply nipple, 18 ... Needle roller.

Claims (1)

[Scope of Claims] 1. A universal joint in which an oil controller formed of a cylindrical container made of porous plastic material is arranged in an oil reservoir at the end of the shaft that communicates with the oil supply hole of the cruciform shaft. 2. The universal joint according to claim 1, wherein the head of the cylindrical container forming the oil controller is spherical and is arranged to face the center of rotation. 3 The plastic material forming the oil controller is a polymeric material such as polypropylene, and the pore diameter is 30 mm.
The universal joint according to claim 1, wherein the diameter is 300 μm. 4. The universal joint according to claim 1, wherein a thrust washer made of a wear-resistant plastic material is provided at the shaft end of the cruciform shaft.