JPH07269573A - Needle roller bearing - Google Patents

Abstract

PURPOSE:To realize a low torque and to facilitate the manufacture by providing solid lubricant chips such as a 'polyloop' and a 'plastic grease' to the clearances between numerous needle rollers arranged on the inside diameter surface of an outer ring. CONSTITUTION:This needle roller bearing is composed of an outer ring 1, needle rollers 2, and a synthetic resin holder 5. The holder 5 is formed thicker compared with a metallic holder, recesses 7 are formed respectively at both inner side surfaces of each pocket 6, solid lubricant chips 8 are inserted to the recesses 7, and their exposed surfaces are contacted to the needle rollers 2. The solid lubricant chip 8 are made generally by baking the mixture of superhigh polymer polyolefin and a grease in the chip form. Since the needle roller bearing is lubricated by the oil component spread from the solid lubricant chips, and the contact between the needle rollers 2 and the solid lubricant chips 3 is a partial contact, the needle roller bearing can be used at a low torque, and even though the chips 8 are softened, they do hardly flow out. Furthermore, it can be manufactured in the number of processes almost the same as in the grease lubrication system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a needle roller bearing, and more particularly to a needle roller bearing having a lubricating function provided by a solid lubricant.

[0002]

2. Description of the Related Art Conventionally, grease has been generally used for lubrication of needle roller bearings.
Alternatively, in order to facilitate maintenance, a solid lubricant made by firing a mixture of an ultrahigh molecular weight polyolefin and grease may be used instead of the grease.

FIG. 10 shows an example thereof, and this needle roller bearing is of a so-called full pack type in which the solid lubricant 3 is filled around the needle rollers 2 arranged on the inner diameter surface of the outer ring 1 without any gap. It is a thing. In the figure, 4 is an axis.

[0004]

Generally, as a method of enclosing a solid lubricant inside a bearing, there are a full pack type as described above and a spot pack type in which a solid lubricant is partially enclosed. Roller bearings have a small contact area with rollers and cages, and solid lubricant does not easily adhere to them.
The spot pack type was not adopted, but the full pack type was used exclusively.

However, the full-pack type has a problem that the solid lubricant comes into contact with all the peripheral surfaces of all the rollers, so that the torque tends to be larger than that of grease lubrication, and the field of use is limited.

In the manufacturing process of a full-pack type needle roller bearing, a solid lubricant material is enclosed and then sintered to separate the solid lubricant adhered to the rollers, inner ring and outer ring after sintering. There is a problem that the number of steps is increased as compared with the conventional grease lubricated product, such as a smoothing step is required.

Further, since the solid lubricant and the iron (roller, inner ring, outer ring) have different coefficients of thermal expansion, the sliding friction between the solid lubricant and the inner and outer rings increases due to the thermal expansion depending on the operating temperature. However, there was a problem that increased the torque.

Further, in the case of the thrust needle roller bearing, the solid lubricant is scattered by the centrifugal force due to the rotation,
After that, there is a problem that it becomes unlubricated.

Therefore, an object of the present invention is to overcome the above-mentioned problems in needle roller bearings using a solid lubricant.

[0010]

[Means for Solving the Problems] A first means for solving the above-mentioned problems is to provide a needle roller bearing comprising at least an outer ring and a plurality of needle rollers arranged on an inner diameter surface thereof. A solid lubricant tip is interposed in the gap between the rollers.

A second means is a needle roller bearing in which needle rollers are inserted into a pocket portion of a cage, and in order to interpose a solid lubricant chip in a gap between the needle rollers, the cage is provided. The solid lubricant tip is inserted into a recess provided on the inner side surface of the pocket portion.

A third means is a needle roller bearing having needle rollers inserted in a pocket portion of a cage, in order to interpose a solid lubricant tip in a gap between the needle rollers.
The solid lubricant tip is inserted between the outer diameter surface of the cage column and the inner diameter surface of the outer ring.

A fourth means is a needle roller bearing having needle rollers inserted in a pocket portion of a cage, in order to interpose a solid lubricant chip in a gap between the needle rollers.
Instead of the needle rollers to be inserted into several pockets of the cage, a needle-shaped solid lubricant tip is inserted.

A fifth means is a full-roller type needle roller bearing in which needle rollers are arranged on the inner diameter surface of the outer ring, and a solid lubricant tip is inserted in a gap between the needle rollers. Is.

[0015]

The needle roller bearing having the above-mentioned means is lubricated by the oil leached from the solid lubricant tip interposed in the gap between the needle rollers, while contacting the tip and the outer ring. Rotate with low torque because of partial contact.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The needle roller bearing of the first embodiment shown in FIGS. 1 to 3 comprises an outer ring 1, a needle roller 2 and a synthetic resin cage 5 for the needle roller 2. The cage 5 is formed thicker than that made of metal, and recesses 7 are formed on both inner side surfaces of the pockets 6, respectively, and solid lubricant chips 8 are inserted into the recesses 7. Needle roller 2 on exposed surface
Is in contact with.

The solid lubricant chip 8 is generally formed by firing a mixture of an ultra-high molecular polyolefin and grease into chips, and more specifically, products such as "polylube" and "plastic grease". Lubricating grease having a dropping point higher than the gelation temperature of the ultra-high molecular weight polyethylene and 95-1 wt% of both ultra-high molecular weight polyethylene having an average molecular weight of 1 x 10 ^{6 to} 5 x 10 ⁶ A mixture of 5 to 99 wt% is filled in the mold having the predetermined shape, heated to a temperature higher than the gelling temperature of the ultra-high molecular weight polyethylene, and then cooled and solidified (Japanese Patent Publication No. 63-23239). reference).

As another example, an average molecular weight of about 1 × 10
^{6 to} 5 × 10 ⁶ ultra-high molecular weight polyolefins having a high gelation point of 5 to 99 wt% of the lubricating grease mixed with 95 to 1 wt% of the ultra high molecular weight polyolefin powder having a particle size of 1 to 100 μm It may be dispersed and held at a temperature equal to or higher than the chemical conversion point.

In any of the above cases, an oil exudation suppressing additive such as a solid wax may be added.

The needle roller bearing described above is lubricated by the oil content leaching from the solid lubricant tip 8, and the needle roller 2
Since the solid lubricant 3 and the solid lubricant 3 are in partial contact with each other, they can be used with lower torque as compared with the conventional full pack type. This point is the same in each of the embodiments described below, but in the case of the first embodiment, the chip 8 is attached to the holder 5.
Since it is inserted into the recess 7 of the pocket 6, there is an advantage that the tip 8 does not easily flow out even if the tip 8 is softened.

Next, the needle roller bearing of the second embodiment shown in FIGS. 4 and 5 comprises an outer ring 1, needle rollers 2 and a cage 5 made of metal. The lubricant tip 8 is inserted into the gap between the outer diameter surface of the column portion of the cage 5 and the inner diameter surface of the outer ring 1. The chip 8 may have a triangular prism shape, a cylindrical shape, or the like in addition to the rectangular prism shape as shown in the figure.

The third embodiment shown in FIGS. 6 and 7 is a thrust needle roller bearing, in which the needle roller 2 held by the cage 5 is held between the two shaft bearing rings 9, 10. Intervenes.

In this case, of the pockets 6 of the cage 5,
Needle rollers 2 are omitted at appropriate positions (four positions in the figure) at regular intervals, and needle roller-shaped solid lubricant tips 8 are inserted instead. In this case, even if centrifugal force acts on the chip 8 due to rotation, there is no possibility of scattering.

The fourth embodiment shown in FIGS. 8 and 9 is a full roller type needle roller bearing which does not use a cage. FIG. 8 shows a standard design value set for the circumferential clearance. In FIGS. 9A to 9D, several rollers of the standard design product are removed to make the circumferential clearance relatively large. It is a thing.

In the case of FIG. 8, between the needle rollers 2 and the outer ring 1
A cylindrical solid lubricant tip 8 having a small diameter is inserted in a gap of a substantially triangular shape between and.

In the case of FIG. 9 (a), a solid lubricant tip 8 in the form of a quadrangular prism is inserted into a relatively large gap between the needle rollers 2. FIG. 9B shows that the portion of the tip 8 near the outer ring 1 is formed in a wide tapered shape. Figure 9
In (c), a triangular prism-shaped solid lubricant tip 8 is inserted into a roughly triangular gap between the needle rollers 2 and the outer ring 1. Further, in FIG. 9D, a solid lubricant tip 8 of the same shape is inserted between the needle rollers 2 and the shaft 4.

[0027]

As described above, the present invention exhibits the following effects.

While maintaining the advantages of the solid lubricant bearing such as no grease leakage, the solid lubricant tip and the needle roller are partially in contact with each other, so the torque is lower than that of the full pack type. it can.

Since the preformed solid lubricant tip is simply inserted between the needle rollers, it can be manufactured in the same number of steps as in the case of conventional grease lubrication.

Since the shape of the solid lubricant tip can be freely changed, an increase in torque due to thermal expansion can be avoided.

It is applicable not only to radial needle roller bearings but also to thrust needle roller bearings.

[Brief description of drawings]

FIG. 1 is a partial sectional view of a first embodiment.

FIG. 2 is a partially longitudinal front view of the same.

[Fig. 3] Partial vertical sectional side view of the above.

FIG. 4 is a partial cross-sectional view of the second embodiment.

FIG. 5 is a partially transverse plan view of the same as above.

FIG. 6 is a side view of the third embodiment.

FIG. 7 is a plan view when one of the bearing rings is omitted from the above.

FIG. 8 is a partial sectional view of a fourth embodiment.

9A is a partial sectional view of a modified example of the fourth embodiment. FIG. 9B is a partial sectional view of a modified example of the fourth embodiment. FIG. 9C is a partial sectional view of a modified example of the fourth embodiment. d) Partial sectional view of a modification of the fourth embodiment.

FIG. 10A is a partially longitudinal front view of a conventional example. FIG. 10B is a partially longitudinal side view of the same.

[Explanation of symbols]

 1 Outer ring 2 Needle roller 3 Solid lubricant 4 Shaft 5 Cage 6 Pocket 7 Recess 8 Solid lubricant tip 9, 10 Race ring 11 Inner ring

Claims (5)

[Claims] 1. A needle roller bearing comprising at least an outer ring and a plurality of needle rollers arranged on an inner diameter surface thereof,
A needle roller bearing, wherein a solid lubricant tip is interposed in the gap between the needle rollers. 2. A needle roller bearing formed by inserting needle rollers into a pocket of a cage, wherein the solid lubricant tip is inserted into a recess provided on an inner surface of the pocket of the cage. The needle roller bearing according to claim 1. 3. A needle roller bearing having needle rollers inserted in a pocket of a cage, wherein the solid lubricant tip is inserted between an outer diameter surface of a column portion of the cage and an inner diameter surface of an outer ring. The needle roller bearing according to claim 1, wherein 4. A thrust needle roller bearing having needle rollers inserted in a pocket of a cage, wherein a solid lubricant chip formed into a needle roller shape is inserted in several pockets of the cage. The needle roller bearing according to claim 1, which is characterized in that. 5. A full-roller type needle roller bearing in which needle rollers are arranged on the inner diameter surface of an outer ring, wherein a solid lubricant tip is inserted in a gap between the needle rollers. Needle roller bearing described in.