JPS6241421A - Thrust ball bearing - Google Patents

Abstract

PURPOSE:To take care that neither stick phenomenon nor fretting abrasion can be caused even if a lubricating oil runs out by providing a ion implantation layers on the rolling contact surfaces of inner and outer races and the surfaces of rolling elements of a thrust ball bearing which receives a centrifugal force with a moving blade changeable pitch axial fan. CONSTITUTION:After cleaning the rolling contact surfaces 2a of inner and outer races 2 of a thrust ball bearing 1 and the surfaces of rolling elements 3, an ion is injected onto the surfaces by means of a well knowledge ion injection method so as to improve the quality of a bearing surface layer. Hereby sliding ability is improved and fretting abrasion resistance is enhanced. As for an element ion to be injected, ions such as N, C, Ar, Cr, Si, B and the like are used. By injecting one or plural kinds of these elements, an ion implantation layer is formed on the surface as illustrated by laying black spots in the figure.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to improvements in thrust ball bearings, and more specifically, to improvements in thrust ball bearings on which centrifugal force acts.

(Prior art) For example, in a rotor blade variable pitch axial flow fan used in a forced draft fan or induced draft fan as shown in FIG. 2, a blade wheel 11 is rotated by an intermediate shaft 15 connected to a motor 14, Centrifugal force acts on the rotor blades 12 attached to the car 11.

The bearing 13 that supports the rotor blade 12 rotates (revolutions) around the intermediate shaft 15 together with the rotor blade while repeating a minute rotational movement under a high load due to the minute rotational movement of the rotor blade, resulting in centrifugal rotation. The load is tens of tons.

Conventionally, thrust ball bearings have been lubricated by applying lubricating oil or filling them with grease.

(Problem to be solved by the invention) However, since thrust ball bearings revolve, centrifugal force causes lubricating oil and grease to scatter, resulting in poor lubrication in a short period of time, resulting in problems such as the bearing sticking. ing.

On the other hand, even if the grease is sealed with a seal to prevent scattering, centrifugal force separates the oil and fat content of the grease from the thickener, causing the oil and fat to flow out, reducing the lubricating performance of the grease.
The bearing will become stuck in a short period of time.

Furthermore, since the strike ball bearing rotates slightly under the large thrust load generated by the rotation of the rotor blades, flexo chatting wear can also cause the bearing to stick.

An object of the present invention is to provide a thrust ball bearing that solves the above problems.

(Means for Solving the Problems) This invention provides a thrust ball bearing that rotates around an axis and receives centrifugal force by rotating around a rotating shaft perpendicular to the axis. The present invention relates to a thrust ball bearing characterized in that an ion-implanted layer is provided on the moving surface and the surface of the rolling elements.

Next, embodiments shown in the accompanying drawings will be described.

The rolling surfaces 2a of the inner and outer rings 2 and the surfaces of the rolling elements 3 of the thrust ball bearing 1 as shown in FIG. 1 are cleaned, and ions are implanted into the surfaces by a known ion implantation method to modify the bearing surface layer. do. This improves sliding properties and fretting wear resistance.

Element ions to be implanted include N, C, and Ar.

Ions such as Cr, Si, and B are used.

One or more of these elements are implanted to form an ion-implanted layer on the surface as shown by the black dots in FIG.

(Test example) Next, an example of a test conducted by the present inventor will be described.

N ions are implanted into the surface of a 10mm round steel ball made of bearing steel (JIS-3UJ2) and a 24n+n+round x 7.8mm+ thick disc using a standard method to form an ion-implanted layer to modify the surface. Then, as shown in FIG. 4, a steel ball is placed on a disk, and while a load P is applied from above, the steel ball is slightly slid from side to side to measure the coefficient of friction μ. The coefficient of friction is determined by measuring the frictional force F with a load sensor installed on the stand to which the disk is attached, calculating μ=F/P, and automatically recording the result. The point where the friction coefficient suddenly increased was considered to be the limit of the lubrication effect, and the limit of the lubrication effect was compared based on the number of repetitions up to that point. The test conditions are as follows.

Test machine: SRV vibration friction and wear tester Load: Two types of 2ON and 4ON Amplitude = 500μm Frequency: 50c/s Temperature: 50℃ Lubrication: ISO220 applied to the friction surface Ion irradiation amount: 3 x 10”/cnl Test results The following table shows the number of repeated frictions until the friction coefficient suddenly increases.From the above table, it can be seen that the sliding properties of the ion-implanted surface are significantly improved compared to the untreated surface. .

(Effects) As explained above, in the thrust ball bearing of the present invention, the rolling surfaces of the inner and outer rings and the surfaces of the rolling elements are modified by ion implantation, so even if the lubricating oil runs out, sticking phenomenon and flexo wear will occur. It is extremely effective when used in applications where centrifugal force is applied.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing an embodiment of the present invention, Fig. 2 is a conceptual diagram of a rotor blade variable pitch axial flow fan suitable for applying the present invention, and Fig. 3 is the same (showing the rotor blade support part). The cross-sectional view and FIG. 4 are elevational views showing the outline of the friction test method. 1... Thrust ball bearing, 2... Inner and outer rings, 2a...
Rolling surface, 3... Rolling element, 11... Blade wheel, 12...
Moving blade, 13... Thrust ball bearing, 14... Motor, 15... Intermediate shaft

Claims (1)

[Claims] In a thrust ball bearing that rotates around an axis and receives centrifugal force by rotating around a rotating shaft perpendicular to the axis, Thrust ball bearing characterized by being provided with an ion-implanted layer