JPH07167146A - Bearing device - Google Patents

Abstract

PURPOSE:To reduce sliding load and heat generation by generating a hard Cr plating film on the surface of a metallic material so as to form a shaft, meanwhile coating Teflon resin impregnated material on the surface of a hard alumite film generated on the surface layer of Al series material so as to form a bearing. CONSTITUTION:This bearing device supports a shaft rotatably, oscillatably, and slidably by reciprocating thrust. For example, in the upper shaft mechanism of an industrial sewing machine 8, an upper shaft 1 transmits the rotational motion of a drive motor to a needle bar 4 as a reciprocating motion through a crankshaft 2 and a connecting rod 3. The upper shaft 1 is rotatably supported with three sliding bearing, i.e., respective upper shaft metals 5-7. In this case, the upper shaft 1 is formed by generating a hard chrome plating film on the surface of a metallic material. Meanwhile, the each upper shaft metal 5-7 is formed by generating a hard anodic oxide coating film on the surface layer of aluminum material, and coating the surface with Teflon resin impregnated material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a bearing device for supporting a shaft which rotates, oscillates, or reciprocally thrusts at high speed.

[0002]

2. Description of the Related Art Conventionally, as a sliding device for a shaft used under severe sliding conditions such as a high speed exceeding 1 m / sec or a high load, a mechanism for continuously supplying oil so as not to run out of a lubricating oil film has been proposed. And bearing material such as white metal, copper alloy, aluminum alloy, or
A material obtained by subjecting steel to heat treatment such as carburizing or nitriding for the purpose of surface hardening has been generally used. Further, for the purpose of imparting wear resistance and seizure resistance, surface treatment such as hard plating and ion plating on metal materials and alumite treatment on aluminum materials have been performed.

An upper shaft mechanism of an industrial sewing machine is a typical machine that slides a shaft at a high speed and a high load while refueling. FIG. 1 is a block diagram of the upper shaft mechanism of the industrial sewing machine. Reference numeral 1 denotes an upper shaft, which transmits rotational movement by a drive motor (not shown) to the needle bar 4 as reciprocating movement via the crankshaft 2 and the connecting rod 3. The upper shaft 1 is supported by three slide bearings, that is, an upper shaft metal L5, an upper shaft metal M6 and an upper shaft metal R7. 8 is a sewing machine main body arm. The upper shaft 1 is made of steel that is carburized or quenched by high frequency, and the three slide bearings are made of cast iron that is nitrided or phosphor bronze.

[0004]

However, when applying a conventional new sliding material to an existing machine part, it is adopted only in one of the shaft and the bearing, and the material of the other material is examined. Was not done enough. Characteristics such as seizure, wear, and sliding load at the time of sliding greatly depend on sliding conditions such as speed and load, as well as compatibility with the mating material. The compatibility means a slip property between two materials and an affinity for adhesion.
Due to insufficient consideration of these mating materials, seizures occurred more frequently than before, seizures did not show the effect of reducing friction even when replaced with new sliding materials. There was a problem of causing wear.

The present invention has been made in order to solve the above-mentioned problems, and is a combination that brings out an extremely excellent friction reducing effect together with sufficient seizure resistance and wear resistance in the presence of lubricating oil. It is an object of the present invention to provide a bearing device having a small sliding load and a low heat generation.

[0006]

In order to achieve this object, in the bearing device of the present invention, the shaft rotates in the bearing,
In a swinging or reciprocating thrust sliding bearing device, the shaft is formed by forming a hard chrome plating film on the surface of a metal material, while the bearing is formed by forming a hard alumite film on the surface layer of an aluminum material. In addition, the surface is coated with a material impregnated with Teflon resin.

[0007]

According to the bearing device of the present invention having the above-mentioned structure, in the fluid lubrication region and the boundary lubrication region, a combination exhibiting excellent seizure resistance and wear resistance as well as an effect of reducing frictional resistance, that is, The shaft side is configured by forming a hard chrome plating film on the surface of the metal material, and the bearing side is formed by forming a hard alumite film on the surface layer of the aluminum-based material and applying a material impregnated with Teflon resin on the surface. It is possible to reduce the sliding load and heat generation and save energy in the system.

[0008]

EXAMPLES An example in which the present invention is embodied in an industrial sewing machine will be described in detail below.

In the upper shaft mechanism of the industrial sewing machine, the material of the upper shaft 1 and the three slide bearings, that is, the upper shaft metal L5, the upper shaft metal M6, and the upper shaft metal R7 is changed in FIG. Except for this, the configuration is conventional.

The upper shaft 1 is made of a steel material as a base material, and the surface thereof is plated with hard chrome with a thickness of about 10 to 30 μm.
After that, the plated surface is polished to a surface roughness of 0.8 Z or less. Next, the upper shaft metal L5, the upper shaft metal M6, and the upper shaft metal R7 that support and slide the upper shaft 1
Is an aluminum alloy whose surface roughness of the sliding surface is 0.8Z or less is used as a base material, which is then anodized and then impregnated with Teflon resin for the purpose of improving self-lubricating property. ing. It is known to use these sliding materials alone for a shaft or a bearing. A feature of the present invention is that these sliding materials are combined as a shaft and a slide bearing, respectively.

Next, a description will be given of the results of a friction wear test in which the present inventor found that the combination of the above two sliding materials was particularly excellent in reducing frictional resistance among various combinations.

FIG. 2 is a schematic view of a pin-on-disc type friction and wear tester used for evaluation of friction and wear characteristics. This test method consists of two pins fixed on a rotating disc test piece 9 at a position that does not coincide with the rotation axis of the disk test piece 9, that is, at a symmetrical position eccentric to the rotation axis by a certain distance. The test piece 10 is pressed. The lubricating oil is supplied on the disc test piece 9 at a constant rate. In this experiment, the sewing machine lubricating oil is supplied at a supply rate of 120 cc / hr.

FIG. 3 is a tabular diagram showing the relationship between the friction coefficient μ and the pressing load P obtained by testing various combinations of sliding materials with the pin-on-disc type friction and wear tester. is there. In this test, the sliding speed V is fixed to 4 m / sec, which corresponds to the upper shaft mechanism of a high-speed industrial sewing machine, and the pressing load P is increased stepwise at every sliding distance of 500 m. As is apparent from FIG. 3, the pin test piece 1 was treated by hard chrome plating on the disk test piece 9 side.
The combination in which the Teflon resin is impregnated after the alumite treatment on the 0 side shows the lowest friction coefficient under each pressing load, and the seizure limit is also good.

FIG. 4 shows a combination in which the disk test piece 9 side is hard chrome plated and the pin test piece 10 side is anodized, and then impregnated with Teflon resin, and the sliding speed V is 4 m / sec. It is a figure of the result of having investigated the change with time of friction coefficient (micro | micron | mu) by fixing the load P to 10 kgf and performing the long-term test of sliding distance 10000m. As is clear from FIG. 4, the above combination gradually decreases with the passage of time, and the low friction is maintained for a long period of time. Further, when the amount of wear of each test piece was measured after this test, a lower value was obtained as compared with the conventional typical combination of carburized steels or carburized steels and nitrided steels.

Here, when the above combination is applied to an actual bearing device, that is, a shaft and a bearing, the pin test piece 10 whose sliding surface is always fixed is taken into consideration in consideration of respective sliding forms. In addition, it is desirable to replace the disk test piece 9 whose sliding surface changes cyclically with time with an axis. Further, from the viewpoint of manufacturing, the hard chrome plating treatment requires post-processing practically, and therefore post-processing such as polishing is easier to perform on the shaft component.

In practice, the upper shaft 1 is made of a steel material plated with hard chrome, and the three slide bearings are made of a high-strength aluminum alloy anodized and then impregnated with Teflon. Built in 5
A high speed operation of 000 rpm was performed. As a result, by reducing the frictional resistance, the power consumption is reduced by about 30%, and the heat generation of the sewing machine body arm 8 is also reduced by about 5 ° C., which is a favorable effect.

In this embodiment, the upper shaft mechanism having a large sliding load is described as an example for the purpose of reducing the motor load of the industrial sewing machine. However, any other rotation, swinging, and reciprocating motion is performed. The combination of the present invention can also be applied to mechanical parts having thrust sliding.

[0018]

As is apparent from the above description, according to the bearing device of the present invention, the shaft side is constituted by forming the hard chrome plating film on the surface of the metal material, and the bearing side is made of the aluminum-based material. Since a hard anodized film is formed on the surface layer and the surface is coated with a material impregnated with Teflon resin, a bearing device with sufficient seizure resistance and wear resistance and low sliding load and heat generation is provided. can do.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an upper shaft mechanism of an industrial sewing machine.

FIG. 2 is a schematic view showing a pin-on-disc type friction and wear tester used for evaluation of friction and wear characteristics.

FIG. 3 Friction coefficient μ for each combination of sliding materials
It is a figure which shows the relationship between and the pressing load P.

FIG. 4 is a diagram showing a change with time of a friction coefficient in a combination of a hard chrome plating treatment and a Teflon-impregnated alumite treatment.

[Explanation of symbols]

 1 Upper shaft 5 Upper shaft metal L 6 Upper shaft metal M 7 Upper shaft metal R

Claims (1)

[Claims] 1. A bearing device in which a shaft rotates, oscillates, or reciprocally thrusts in a bearing, wherein the shaft is formed by forming a hard chrome plating film on the surface of a metal material, while the bearing is formed. A bearing device characterized in that a hard alumite film is formed on the surface layer of an aluminum-based material, and the surface thereof is coated with a material impregnated with Teflon resin.