JPS6280242A - Copper-base sintered thrust bearing containing oil - Google Patents

Abstract

PURPOSE:To obtain a copper-base sintered thrust bearing contg. oil and having superior lubricity and wear resistance by adding a specified amount each of powder of the carbide of a group IV, V or VI elements in the periodic table and powder of a solid lubricant to powder of a copper-base sintered bearing material contg. oil. CONSTITUTION:A mixture consisting of 2-10vol% powder of the carbide of a group IV, V or VI element in the periodic table, 2-10vol% powder of a solid lubricant and the balance powder of a copper-base sintered bearing material contg. oil is sintered to manufacture a copper-base sintered thrust contg. oil. The carbide may be WC, TiC, VC, Cr3C2, NbC, Mo2C, HfC or TaC, and the solid lubricant may be graphite or molybdenum disulfide. The thrust bearing for high load does not damage or wear a shaft of an opposite member.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a copper-based sintered oil-impregnated thrust bearing.

(Prior Art) In the capstan flywheel or direct drive type capstan motor of a tape recorder or VTR, as shown in FIGS. 5(A) and (B),
Thrust loads are often received at the tip of the shaft.

In the belt-driven capstan shown in Fig. 6(A), the shaft l is supported by the metal 2゜2 in a through hole of a housing 3 to which a cylindrical metal 2゜2 is fixed, and is rotatably attached. It will be done. Housing 3 is chassis 4
is fixed with screws. Shaft 1 is flywheel 5
and is driven by a belt (not shown). The lower end of the shaft l has an R-shape and is supported by a thrust bearing 6.

When the tape runs, the tape is sandwiched between the upper part of the shaft 1 and a pinch roller (not shown) in the direction of the arrow, and is fed by the belt drive of the flywheel 5. A load from the flywheel 5 and the like acts on the thrust bearing 6 .

In the direct drive type capstan shown in FIG. 6(B), the shaft 2 is similarly rotatably attached to a housing 13 to which a cylindrical metal 12.12 is fixed. The housing 13 is fixed to the chassis 14 with screws. The lower end of the shaft 11 is fixed to the rotor 15. The upper end of the shaft 11 has an R-shape,
In contact with the thrust bearing 16. The thrust bearing 16 is fixed to the housing 13 by press fitting. Magnet 18.18 fixed to Shaan 14 via stator 17
is opposed to the rotor 15 with a predetermined air gap in between.

When the tape runs, the tape moves along the shaft 11 in the direction of the arrow.
It is sandwiched between the central part of the holder and a pinch roller (not shown), and is rotationally driven by magnets 18 and 18. The thrust bearing 16 is acted upon by the attractive force of the magnet 18.18.

(Problems to be solved by the invention) Generally, the capstan shaft 1. l! The thrust load of
As shown in the figure, the R part at the tip of the shaft and the surface are often covered with a flat, lubricating resin such as nylon or polyacecool [6,16]. At this time, the weight of the flywheel or rotor or the magnetic attraction force acts in the thrust direction of the shaft, and the size of the force may range from several hundred grams to 1 to 2 kilograms. Such a large load often causes problems such as abrasion of the resin and a change in the air gap in the thrust direction.

It is difficult to prevent wear, perhaps because the resin contains a solid lubricant such as graphite.

On the other hand, if a hard and lubricating material such as ceramic is used as the thrust bearing material, the thrust bearing material will not wear out, but on the contrary, the R part at the tip of the shaft will wear out, and on the contrary, This will lead to bad results.

In this way, the thrust bearing that receives the R portion at the tip of the shaft will not give good results whether it is too hard or too soft.

In other words, it is difficult to minimize wear on either the shaft or the thrust bearing using off-the-shelf materials. Therefore, there has been a demand for the development of materials suitable for thrust bearings.

An object of the present invention is to provide a thrust bearing for high loads that has excellent lubricity and wear resistance, and does not damage or wear out the mating shaft.

(Means for solving the problems) The copper-based sintered oil-impregnated thrust bearing according to the present invention has a
ol% carbide powder of elements from groups IV to VI of the periodic table, 2
It is made by sintering and oil-impregnating ~10 vol% solid lubricant powder and the remaining copper-based sintered oil-impregnated bearing material powder.

The composition of the powder of copper-based sintered oil-impregnated bearing material is JIS [3K15
It is not limited to those specified in 815BKI type (bronze type) and type 2 (lead bronze type), but may be selected from a wide range of copper type sintered materials in consideration of conformability and lubricity. Further, as the solid lubricant, graphite, molybdenum disulfide, etc. are used.

(Function) The carbide of groups IV to VI of the periodic table improves the wear resistance of the copper-based sintered oil-impregnated thrust bearing. Solid lubricants also improve the lubricity of thrust bearings.

(Example) Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The present inventors have discovered that thrust bearings manufactured by sintering and oil-impregnating powder used in copper-based sintered oil-impregnated bearing materials have less wear compared to resin, and do not wear out the tip of the shaft compared to ceramic. I expected it. The components of this copper-based sintered oil-impregnated thrust bearing are not limited to those stipulated by JIs K1581 5BK type 1 (bronze-based) and type 2 (lead bronze-based), but are made from a wide range of copper-based sintered materials with good conformability and lubricity. Just consider and choose.

The oil contained in the thrust bearing material contributes to the lubrication of the shaft and thrust bearing, but complete (fluid) lubrication that forms an oil film between the two cannot be expected, resulting in boundary lubrication. Therefore, to compensate for this, it is necessary to add a solid lubricant (eg, graphite, molybdenum disulfide).

Thrust bearings made of copper-based sintered oil-impregnated materials with graphite or molybdenum disulfide added have significantly improved wear resistance compared to resin materials at low loads, that is, loads of several hundred grams or less. Ta.

However, as the load increased, the thrust bearing became more abrasive, making it unusable.

Therefore, in order to improve the wear resistance of thrust bearings, carbides of elements belonging to Groups IV to VI of the periodic table were added to copper-based sintered oil-impregnated material, and as explained below, the wear resistance was improved. We found that there was a significant improvement.

The thrust bearing was manufactured as follows. Sn powder 1
0wt%, graphite powder 3wt%, WC powder 10w
A mixed powder having a composition of t% (5.4 vol%) and the balance being Cu powder was compression molded into a tablet shape of φ11.3×10 2 . After sintering this at 700° C. for 30 minutes in a hydrogen gas atmosphere, it was impregnated with mineral oil equivalent to ISO VG 220 under reduced pressure. At this time, the oil content was 18 vol%. (It should be noted that other methods may be used to manufacture the copper-based sintered oil-impregnated thrust bearing.) As shown in Fig. 6, the end R portion of the φ3 shaft made of stainless steel 5US420J2 is inserted into the sintered oil-impregnated thrust bearing. Applying a load of 2 kg and setting the rotation speed of the shaft to 90 Orpm, 1000
A time running test was conducted.

As shown in FIG. 2, the amount of wear increased rapidly at first, and then became almost constant after about 500 hours.

This indicates that the friction between the tip of the shaft and the thrust bearing improves their familiarity, the friction is gradually reduced, and when the two become sufficiently familiar, steady-state deafness occurs. As comparison materials, similar running tests were conducted on a copper-based sintered oil-impregnated bearing produced in the same manner without containing WC and C (graphite), and a thrust bearing using polyacetal resin, which is currently commonly used.

As a result, when comparing the results after 500 hours, as shown in the table, the product of the present invention showed a significant improvement in wear resistance compared to a copper-based sintered oil-impregnated thrust bearing that does not contain WC or C.

Table 1 shows the change in the wear amount of the thrust bearing when the amount of WC added is changed. Carbide content lovol%
When the amount exceeds , the wear of the thrust bearing progresses rapidly. This is because the thrust bearing has become too hard.
The shaft began to wear out, and as a result, the thrust bearing also wore out. On the other hand, if the carbide content is less than about 2v01%, the wear of the thrust bearing will increase, similar to those without carbide. Therefore, the content of WC is preferably in the range of 2 vol% or more and 10 vol% or less.

As additives, carbides of elements from groups IV to VI of the periodic table other than WC (typical examples include TiC and VC.

CrJCt, NbC, Mo, C, HrC, TaC, etc.)
A similar improvement in abrasion resistance was observed when using the following methods, and no significant difference was observed in the effects.

3(A) to (D) Carbides of elements from groups IV to VI of the periodic table WC and '1'iC are respectively added to the copper-based sintered oil-impregnated material.

The radial crushing strength is shown for those to which MoC and TaC are added. If the amount added is 10 vol% or less, the radial crushing strength is 15
kg/mm2 or more can be secured. Radial crushing strength is a quantity representing a type of bending strength of a cylindrical sintered oil-impregnated bearing. (JI
In SBI581, copper-based sintered oil-impregnated bearings have an oil content of 185
(The above specifies that the radial crushing strength is 15 kg/mm" or more.) Copper-based sintered oil-impregnated materials become harder but more brittle as the amount of carbide increases, so the radial crushing strength decreases. Amount of carbide added is lovol%, and the radial crushing strength is almost the same value regardless of the type of carbide, l 5 kg/n+n
Slightly larger than +2. Therefore, the carbide content is
It is preferably 10 vol% or less.

As shown in FIG. 4, if the content of graphite as a solid lubricant is less than 2 vol %, the shaft is likely to wear, although the degree varies depending on the carbide content. On the other hand, as the graphite content increases, the radial crushing strength decreases, and when it exceeds 10 vol%, the radial crushing strength decreases to 15 kg.
/mm'' cannot be ensured, and the wear of the thrust bearing due to the decrease in strength increases.Therefore, the graphite content is preferably 2 to 10 vol%.

As described above, the wear resistance of the copper-based sintered oil-impregnated thrust bearing is improved by containing 2 vol% or more and 10 vol% or less of carbides of Group IV to VI elements of the periodic table in the copper-based sintered oil-impregnated material.

These carbides have a Vickers hardness of 1800 kg/mm
It has a hardness of more than Lubricity, ■ Lubricity due to impregnated oil, ■ Solid lubricity of graphite (solid lubricant), ■ Wear resistance due to dispersion of hard Group IV to VI group charcoal carbide in the matrix. It also exhibits excellent wear resistance and lubricity.

The thrust bearing explained above is shown in FIG. 6(A).

It can be used for the capstan having the configuration shown in (B).

However, in the configuration shown in FIG. 6(B), when the thrust bearing 16 is threaded, as shown in FIG. It is embedded in a support material 16'' such as resin, and the support material 16'' is fixed with screws.

(Effects of the Invention) According to the present invention, it is possible to provide a sintered oil-impregnated thrust bearing for thrust load receiving that has good compatibility with the shaft, therefore does not damage or wear the shaft, and is also resistant to wear itself. be able to.

[Brief explanation of drawings]

FIG. 1 is a graph showing the wear resistance of a copper-based sintered oil-impregnated thrust bearing to which WC has been added versus the amount of WC added. FIG. 2 is a graph showing the running characteristics of the wear resistance of a copper-based sintered oil-impregnated thrust bearing to which WC is added. Figure 3 (A) to (D) are WC, TiClMo, respectively.
It is a graph of the radial crushing strength of a copper-based sintered oil-impregnated material to which C and TaC are added. FIG. 4 is a graph showing the wear resistance of a copper-based sintered oil-impregnated thrust bearing to which graphite has been added versus the amount of graphite added. FIG. 5 is a sectional view of an example of a thrust bearing. FIGS. 6A and 6B are cross-sectional views showing the arrangement of the capstan shaft and thrust bearing, respectively. FIG. 7 is an enlarged sectional view of the contact portion between the shaft tip and the thrust bearing. 1... Shaft of capstan, 6... Thrust bearing, 11... Shaft of capstan, 16... Thrust bearing. Patent applicant: Nippon Kagaku Yakin Co., Ltd.
People Patent Attorneys Previously 2 Idiots Figure 113

Claims (1)

[Claims] (1) Sintering 2 to 10 vol% of carbide powder of Group IV to VI elements of the periodic table, 2 to 10 vol% of solid lubricant powder, and the remaining powder of copper-based sintered oil-impregnated bearing material, and Copper-based sintered oil-impregnated thrust bearing.