JPS6023671A - Piston rod of oil hydraulic shock absorber - Google Patents

Abstract

PURPOSE:To improve abrasion resistance and corrosion resistance and allow coloring by forming a thermally sprayed layer on the sliding surface of a piston rod, applying nitriding treatment on the non-sliding surface, and further applying oxidation treatment on this nitride layer. CONSTITUTION:A thermally sprayed layer A with a predetermined thickness is formed on the sliding surface 11, against a bearing, of the steel 10 of a piston rod 4 applied with predetermined machining, degreasing treatment, etc. This thermally sprayed layer A is formed with, e.g., chrome oxide, aluminum oxide. After the steel 10 formed with the thermally sprayed layer A is degreased and washed, a nitride layer B of Fe3N, Fe4N is formed on the non-sliding surface 12 of the steel 10, and further oxidation treatment is applied on it to form an oxide/nitride layer C.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a piston rod (inner dup) of a hydraulic shock absorber.

(Prior art) Hydraulic pressure used in motorcycles, etc.! ! ? In addition to functionality and durability, JI appliances are required to have an aesthetic appearance. Conventionally, the surface of the piston rod of the shock absorber was generally plated with hard chrome, but in order to further enhance its aesthetic appearance, this The applicant applied a nitriding treatment to the surface of the piston rond, and further applied oxidation treatment to this nitrided layer, making it possible to color the surface of the piston rond black etc. while maintaining wear resistance almost equivalent to hard chrome plating. An application has been filed (Patent Application 11
d 57-27757, etc.).

However, although products with such surface treatment have excellent corrosion resistance, they cannot be prevented from being used for long periods of time (the sliding surface of the piston rond gradually wears out, and the black layer gradually comes off). I was worried that it would happen.

Therefore, the present applicant, J.
As No. 243, it has been proposed that the surface of the piston rod is thermally sprayed (coated) with chromium oxide, aluminum oxide, etc. to sufficiently improve wear resistance and corrosion resistance while also being able to be colored black or the like.

However, after forming this thermal spray layer, 1. In this case, the wear of the piston rod is almost eliminated and the corrosion resistance is excellent, but there are problems in that it takes many man-hours to manufacture and the cost is considerably high.

(Objective of the Invention) The object of the present invention is to provide a piston [J] which has improved wear resistance and corrosion resistance, and has the ability to be colored, while reducing cost.

(Structure d3 and operation of the invention) This invention forms a sprayed layer on the sliding surface of the piston rod, performs a nitriding treatment on the non-1N sliding surface, and further performs an oxidation treatment on this nitrided layer to form an oxynitride layer. is formed.

In other words, the sliding surface of the vist front is coated with molten metal, which has excellent wear resistance.
11i'j to sufficiently prevent wear, and also to reduce costs by forming an inexpensive oxynitride layer on the non-sliding surface where there is no fear of wear.

(Embodiment) Figures 1 and 2 show an embodiment of the present invention, and show a configuration diagram and a partial sectional view C' of a hydraulic shock absorber 1, and an example of a shock absorber 1 used for a front fork, etc. There is.

This shock absorber 1 has an outer cove 3 connected to a wheel 2.
A bisto front (inner tube) 4 is supported in a sliding manner via bearings 5 and 6, and as is well known, the wheel 2 is supported by a hydraulic damper in a cylinder 7 and a spring 8 in a piston rod 4. It is designed to reduce image strikes and the like transmitted from the side to the handle 9.

In this embodiment, when manufacturing the bisto front 4, as shown in FIG. A sprayed layer A of a predetermined thickness of 11 (for example, 30μ or more) is applied to the dark moving surface 11 (range corresponding to 9 in FIG. 2) relative to 5.
form. The sprayed layer A at the mouth is made of, for example, chromium oxide (C+
゛, Ot>, formed of aluminum oxide (AC, 0,).

The thermal spraying method may be plasma spraying, explosive thermal spraying, or flame spraying, but here we will explain the thermal spraying method, which has a relatively low porosity of the molten Q.1 layer and is relatively good in terms of corrosion resistance. However, in this case, the non-sliding surface 12 of the steel material 10 (
Measures to prevent thermal spraying are taken in areas corresponding to l+, , I+ in Fig. 2).

When chromium oxide or aluminum oxide powder is injected into the inside of the D gun, this powder becomes hot due to the ignition of the spark plug. Together with the scum, it becomes a semi-molten state and is sprayed onto the 18 moving surfaces 11 of the steel material 10. The explosion recycle of the spark plug, which is placed inside the D-gun, is 71 to 8 times/second, and the internal temperature of the D-gun is 276.
At 0° C. or higher, the 9j thrust speed of the solvent with respect to the steel material 10 is set to approximately @ speed.

In this way, a sprayed layer is formed on the sliding surface 11 of the steel material 10. At this time, by appropriately selecting the structural components of the sprayed layer A, it is possible to color it in various colors. For example, if chromium oxide is used, it can be colored with black. A dissolved OA layer Δ is obtained.

Then, after degreasing and cleaning the uA layer 10 on which the melt side layer was formed, Fe2N was applied to the non-sliding surface 12 of the steel material 10.

A nitride layer B of FOIN is formed, and an oxynitride layer C is further formed on it. In this case, the sprayed layer A is subjected to nitridation prevention treatment, and the nitride layer B1 and oxynitride layer C are also formed on the inner surface 13 of the piston rod 4.

That is, ammonia gas (Nl-L) is heated in a furnace at a temperature of 500° or more at r2N+-1,→31-1. +2NJK
After decomposition, expose the fPl material 10 to this atmosphere.

As a result, the ridges Fe on the surface of the tfII material 10 react with activated nitrogen, resulting in rN+3Fe→Fe, NJrN+4
Change sequentially such as Fe-+Fe r NJ, and select the temperature and time appropriately IN'! Particularly, on the non-sliding surface 12a3 and the inner surface 13 of the steel material 10, a uniform nitrided layer B of FOzNJjyypi1-(],N without a porous layer of an appropriate thickness is formed. In this case, immersion gas may be mixed into the annealing gas.

Subsequently, the surface of this nitride layer 13 is coated with a separate cloth or the like for 1tll.
After rubbing, f, rl 1m salt such as NaO+137. /
1%, 1ri 01-152.6%, Na No, 10.0
% to form an oxynitride layer C on top of the nitride layer B.

This oxynitride layer C becomes yellow when treated at 300°C in nitrate, blue when treated at 350°C, and black when treated at /100°C.
colored. d3. In addition to nitrate treatment, homogenization treatment, black dyeing, etc. may be used for the liquefaction treatment.

Then, the surfaces of the oxynitride layer C of this steel material 10 and the sprayed layer Δ are polished, etc., to form the piston rod 4 of the hydraulic 11fj device 1.

As a result of various tests, the molten #J layer △ on the vist front 4 and the sliding surface 11 formed in this way has superior corrosion resistance of 1
It has been confirmed that C has a lower wear resistance and a lower wear resistance.

Further, the layer C of the acid chamber 1 part of the non-sliding surface 12 has corrosion resistance and abrasion resistance equivalent to or higher than that of hard chrome plating, while providing an extremely smooth surface. Furthermore,
It has excellent scratch resistance (JJ properties) and is inexpensive to manufacture.

Therefore, the entire surface of the screw rod 4 can be colored the same color, such as black, and it is possible to provide the piston rod 4 in a color that suits the customer's preference.
The sliding surface 11 of the piston U-end 4 may wear out over a long period of time, or
Corrosion of the various parts of the rond is prevented, and durability is sufficiently improved.

The surface of the piston 4 is not scratched and always maintains a beautiful appearance, and the thermal spray layer △
is formed only on the sliding surface 11 of the piston rod 4, and an inexpensive oxynitride layer C is formed on the non-sliding surface 12, where there is no fear of wear, resulting in a significant cost reduction without excessive quality. It becomes possible.

In addition, the sliding properties of each surface of the piston rod 4 are improved, and bending leakage and the like as the hydraulic shock absorber 1 can be more effectively prevented. Furthermore, the oxynitride layer O is formed on the inner surface of the piston rod 4, and is sufficiently effective against wear against the spring 8.

(Effects of the Invention) It is possible to improve the aesthetic appearance by making the piston U-end colorable, and there is an effect that the manufacturing cost can be reduced while sufficiently improving the corrosion resistance and wear resistance of the piston.

[Brief explanation of the drawing]

FIGS. 1 and 2 are a block diagram and a partial sectional view of an oil F1 shock absorber according to an embodiment of the present invention, and FIG. 3 is an external view of the piston rod. 1... Hydraulic shock absorber, 4... Piston rod, '11
...Sliding surface, 12...Non-sliding surface. Patent applicant Kayaba Kogyo Co., Ltd. Figure 3

Claims (1)

[Claims] A piston rond for a hydraulic shock absorber in which a sprayed layer is formed on the sliding surface, a nitriding treatment is applied to the non-sliding surface, and an oxynitride layer is formed by oxidizing the nitriding layer.