JP2000130405A - Hydraulic cylinder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve anticorrosion and abrasion resistance by applying nickeling treatment on a surface portion making contact with a working medium of a constituting member of a hydraulic cylinder, applying nickeling on a lower layer of a sliding portion and applying double-layer plating of hard chrome plating on its upper layer part. SOLUTION: Hardness is improved by applying nickeling 16 on inner su surfaces 01a and 05a making contact with water of both members of a cylinder tube 01 and a bottom cover 05 and applying hard chrome plating 17 on the nickeling 16 on the inner surface 01a of the cylinder tube 01 on which a piston packing 07 slides. Additionally, double-layer plating is applied on a surface 02a which is a contact part with water as well as a sliding surface like the cylinder tube 01 of a piston rod 02, namely, the nickeling 16 on the lower layer side and the hard chrome plating 17 on its upper layer. Consequently, it is possible to provide a hydraulic cylinder having required anticorrosion and abrasion resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a hydraulic cylinder using a corrosive liquid such as water as a working medium.

[0002]

2. Description of the Related Art FIG. 6 shows a conventional hydraulic cylinder using oil as a working medium. In FIG. 6, the hydraulic cylinder includes a cylinder tube 100, a piston rod 101, a piston 103, a nut 104,
Bottom cover 105 having inflow / outflow port 112, head cover 106 having inflow / outflow port 113, piston packing 107, rod packing 108, dust seal 109, piston wear ring 110, piston rod wear ring 111, inflow / outflow ports 112 and 113.
And so on.

The piston 103 is reciprocally slidably fitted on the inner periphery of the cylinder tube 100, and the piston rod 101 as an output end is connected to a nut 104.
And is fixed via washers 23, 23. The inside of the cylinder tube 100 contains the piston 103
The oil chamber 122 is divided into two oil chambers 122 and 123. One of the oil chambers 122 is open with the inflow / outflow port 113, and the other oil chamber 123 is provided with the inflow / outflow port 112.
Is open.

During operation of the hydraulic cylinder, pressure oil whose flow direction has been switched by a switching valve (see FIG. 1) is transferred from the inflow / outflow port 112 to the oil chamber 123 and from the inflow / outflow port 113 to the oil chamber 122, respectively. When the piston 103 is introduced and acts on the piston 103, the piston 103
6 is displaced to the left in FIG. 6 due to the area difference between the two, and the displacement output is taken out through the piston rod 101 to drive a load (not shown) connected to the piston rod 101.

[0005] In such a hydraulic cylinder, since the working medium is oil, the material of the main member is carbon steel (J).
ISSTKM, S45C, SS400, etc.), and the surface of the piston rod 101 exposed to the outside from the cylinder tube 100 is coated with hard chrome plating 101a as a measure against foreign matter from outside and abrasion of a sliding portion. Hardness. In addition, the piston packing 10
In some cases, the inner surface of the cylinder tube 100 on which the sliding member 7 slides is also provided with hard chrome plating 100a in order to increase the hardness as a measure against wear of the sliding portion.

In recent years, however, a hydraulic system having a hydraulic cylinder using water as a working medium has been adopted instead of the hydraulic system having a hydraulic cylinder as described above with a primary focus on environmental protection and cleaning of drainage and the like. Is being done.

In such a hydraulic system, since water as a working medium is corrosive, pumps and various control valves, which are components of the system, as well as hydraulic cylinders for driving the apparatus, have conventionally been used. Normal steel materials, mainly carbon steel materials used for hydraulic cylinders and the like, cannot be used. For this reason, various devices constituting the above-mentioned water pressure system are made of ceramics or plastics, mainly stainless steel, which is a corrosion-resistant material. When the hydraulic cylinder for such a hydraulic system has a structure similar to that of the hydraulic cylinder in FIG. 6, the main material is stainless steel (such as JISSUS304) such as the cylinder tube 100, the piston rod 101, and the bottom cover 105. Piston 103 and head cover 1
It is manufactured by combining stainless steel, copper alloy material, etc.

In addition to the above, a hydraulic cylinder as shown in FIG. 7 is provided as an example of a hydraulic cylinder for a hydraulic system in which a main part is made of a corrosion-resistant material. 7, reference numeral 01 denotes a cylinder tube; 03, a piston fitted reciprocally slidably in the cylinder tube 01; 35, a cylinder body having a fluid (water) inflow / outflow port 35a; A cylinder cover having a port 34a; 02, a piston rod for taking out output fixed to the piston 03; 33, a bush for supporting the piston rod; 32, a retainer for the piston rod 02;
Is a nut for the piston 03.

In the above hydraulic cylinder, the cylinder tube 01 is made of stainless steel whose inner surface is polished, the cylinder body 35, the cylinder cover 34 and the piston 03.
Is made of a corrosion-resistant material such as stainless steel, stainless steel having a piston rod 02 on the outer periphery of which hard chrome plating is applied, and bush 33, bush 32, nuts and the like are made of high-strength brass or bronze.

[0010]

The hydraulic cylinder used in the above-mentioned hydraulic system has a hydraulic cylinder as shown in FIG. 6 of a hydraulic specification, or a hydraulic cylinder as shown in FIG. In both cases, the long piston rod 101 or 03, the cylinder tube 100 or 01, etc. are made of expensive stainless steel.
The equipment cost is greatly increased, and the machining cost is also high because stainless steel is inferior in machinability to carbon steel or the like.

An object of the present invention is to provide a hydraulic cylinder using a corrosive working medium such as water, which has high corrosion resistance and abrasion resistance, and which can be manufactured at a lower cost than a conventional stainless steel hydraulic cylinder. To provide a hydraulic cylinder.

[0012]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and the first means, which is the gist thereof, is:
In a hydraulic cylinder using a corrosive liquid such as water as a working medium, a component of the hydraulic cylinder is subjected to nickel plating on a portion requiring corrosion resistance, such as a surface in contact with the working medium, and a sliding portion. The parts requiring wear resistance are characterized in that the lower layer is plated with nickel and the upper layer is plated with two layers of hard chrome.

A second means is the first means, wherein the base material of the component to be subjected to the nickel plating or the two-layer plating is based on carbon steel.

In the first means or the second means, the nickel plating has a plating thickness of 10%.
It is preferable that hard chromium plating is applied to a thickness of 20 to 30 microns.

According to the above means, in a hydraulic cylinder using a working medium having a corrosive property such as water, the base material is made of carbon steel, and nickel plating is applied to a surface of a portion which comes into contact with the working medium. In addition, a component having high corrosion resistance can be obtained by a low-cost means that nickel plating is performed on the surface of a base material based on carbon steel which is inexpensive and has good machinability.

[0016] Further, a hard chromium plating on the surface of which the working medium easily penetrates is provided by forming a nickel plating on the lower layer and a hard chromium plating on the upper layer for the parts requiring abrasion resistance such as sliding parts. The lower layer is covered with nickel plating to form a highly corrosion-resistant nickel plating layer below the hard chromium plating layer with high wear resistance. Can be obtained.

Therefore, according to the above-mentioned means, the cost is lower than that of a conventional hydraulic cylinder using stainless steel for the cylinder tube, piston rod, etc., which are long members.
The hydraulic cylinder is made by extremely low-cost means of applying nickel plating on the base material based on carbon steel with good machinability or two-layer plating of hard chrome plating on the upper layer and nickel plating on the lower layer. Can be configured,
The device and processing cost of the hydraulic cylinder are greatly reduced as compared with the conventional one.

The third means may be a hydraulic cylinder using a corrosive liquid such as water as a working medium in addition to the first means or the second means. A magnet is fixed to a portion facing the liquid chamber in which the working medium is stored.

According to such a means, foreign matter such as dust entering from the outside can be captured by the magnet provided facing the liquid chamber, and sliding between the cylinder tube and the piston or the outer peripheral portion of the piston rod can be performed. Problems such as seizure of the sliding portion due to foreign matter being caught in the moving surface are prevented.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail with reference to FIGS. 1 to 3 and FIGS. FIG. 1 is a diagram showing a longitudinal section of a hydraulic cylinder and a system of a hydraulic system according to a first embodiment of the present invention, FIG. 2 is a sectional view of a principal part of a cylinder part, and FIG. 3 is a sectional view of a principal part of a piston part. .

In FIG. 1, 01 is a cylinder tube,
03 is a piston fitted in the cylinder tube 01 so as to be reciprocally slidable, 02 is a piston rod, 30 is the center of the cylinder, and the piston 03 is provided at one end of the piston rod 02 with the washers 23, 23 and a nut 04. Has been fixed by. An output end, which is the other end of the piston rod 02, is connected to a load (not shown).

A bottom cover 05 is fixed to one end of the cylinder tube 01 by welding, screw connection, or the like, and a head cover 06 to which the piston rod 02 is reciprocally slidably fitted is welded to the other end. The cylinder tube 01 is partitioned into two water chambers 21 and 22 by the piston 03, while the cylinder is fixed by screw connection or the like and sealed. Reference numeral 12 denotes an inflow / outflow port provided in the head cover 06, which communicates with the one water chamber 22, and reference numeral 13 denotes an inflow / outflow port provided in the bottom cover 05, which communicates with the other water chamber 21.

02a is a dust seal, 08 is a rod packing, 11 is a wear ring for the piston rod 02,
3a is an O-ring for sealing the outer periphery of the piston rod 02 and the inner periphery of the piston 03. 07,07 is a piston packing, 10 is a wear ring for piston 03,
24 is an O-ring for sealing the outer periphery of the head cover 06. Each of the O-rings is made of a water-resistant material such as nitrile rubber, and the wear rings 10 and 11 are made of a material such as phenol resin.

Further, 14 is a hydraulic pump, 15 is a water switching valve, 20 is a water tank, 15a is a water pipe connecting the switching valve 15 and the inflow / outflow port 12, and 15b is a water pipe connecting the switching valve and the inflow / outflow port 13. A water pipe to be connected, and the hydraulic pump 1
The flow of the water sent from 4 is switched by the switching valve 15,
Water chamber 22 or 2 through water pipe 15a or 15b
1 is supplied and discharged.

During the operation of the hydraulic cylinder, water as a working medium pressurized by the hydraulic pump 14 is:
The flow direction is switched by the switching valve 15, and for example, the water pipe 1
5a flows into the water chamber 22 through the inflow / outflow port 12, and from the water pipe 15b through the inflow / outflow port 13 to the water chamber 2.
1 and acts on the piston 03. By the action of such water pressure, the piston 03 and the piston rod 02
The piston 03 is displaced leftward in FIG. 1 due to the area difference between the water chamber 21 side and the water chamber 22 side, and the displacement output is taken out of the piston rod 02 to an external load (not shown).

The internal leakage of water at the fitting portion between the piston 03 and the piston rod 02 is prevented by the O-ring 03a, and the internal leakage of water between the inner surface 01a of the cylinder tube 01 and the outer periphery of the piston 03. Is blocked by the piston packing 07 and the piston rod 02
The leakage of water to the outside at the fitting portion between the head cover 06 and the head cover 06 is prevented by the rod packing 08. Further, the dust seal 09 prevents dust from entering the inside of the hydraulic cylinder from outside.

The basic structure and operation of the hydraulic cylinder described above are the same as those of the conventional hydraulic cylinder. However, in the embodiment of the present invention, the cylinder tube 01, the piston 03, the piston rod 02, the bottom cover 05, and the head cover 06 are used.
The surface of a member that comes in contact with water is subjected to corrosion resistance, or surface treatment having corrosion resistance and wear resistance.

That is, FIG. 2 shows a surface treatment state of the cylinder tube 01 and the bottom cover 05, and FIG. 3 shows a surface treatment state of a fitting portion such as the piston rod 02, the piston 03 and the nut 04 and a screw fastening portion. In FIG. 2, the cylinder tube 01 and the bottom cover 05 are made of JISSTKM material and S43C as in the case of the conventional hydraulic cylinder, but nickel plating 16 is applied to the inner surfaces 01a and 05a of both members that come into contact with water. To improve corrosion resistance. Further, as for the inner surface 01a of the cylinder tube 01 on which the piston packing 07 slides, a hard chrome plating 17 is applied on the nickel plating 16 in order to increase the hardness, thereby increasing the hardness and improving the wear resistance.

In FIG. 3, the piston rod 02 is made of carbon steel of JIS43C similar to a conventional hydraulic cylinder, and is a sliding surface and a surface 02a which is a contact portion with water similarly to the cylinder tube 01. Is nickel plating 16 on the lower layer side and hard chrome plating 17 on the upper layer.
A layer plating treatment is applied to improve corrosion resistance and wear resistance. Piston rod 02 that does not require wear resistance
The fitting portion 03b of the piston 03 and the fitting portion 03b and the screw portion 03c of the nut 04 are coated with only nickel plating 16 as a corrosion resistant treatment.

In the above embodiment, the hard chromium plating 17 applied to the inner surface 01a of the cylinder tube 01
In the treatment, the surface is porous, and fine cracks and pinholes are generated.Water invades from this part and corrodes the base material. May cause. In order to prevent such a problem from occurring, the inner surface 01a of the cylinder tube 01 is coated with nickel plating 16 as a preparation for hard chrome plating. This nickel plating 16
Since there is no fine crack or pinhole unlike the hard chromium plating 17, it is possible to completely prevent water from entering the surface of the base material. As described above, in this embodiment, the nickel plating 16 prevents the water which is the corrosive fluid from entering, and furthermore, the inner surface 01a of the cylinder tube 01
By applying a hard chrome plating 17 on a nickel plating 16 in a place requiring high hardness such as a sliding portion as described above, corrosion resistance and wear resistance can be ensured.

On the other hand, the piston 03 and the head cover 0
6 does not basically have a sliding portion or the like, so that only the corrosion resistance is taken into consideration, and nickel plating 16 is applied only to the contact surface with water. Furthermore, the piston rod 0
The nut 04 for fixing the piston 2 and the piston 03 is made of stainless steel having excellent corrosion resistance. Further, the cylinder tube 01, the bottom cover 05, and the head cover 06
The outer surface portion is not subjected to the plating treatment as described above, and only the rust-proof coating is applied similarly to the conventional hydraulic cylinder.

In the hydraulic cylinder configured as described above, the flow path (water pipes 15a, 15b) is switched by the switching valve 15 to supply the pressurized water to the inflow / outflow port 12 and / or 1
3, when the piston 03 and the piston rod 02 are operated, the piston packing 07 and the cylinder tube 0 on which the wear ring 10 of the piston slides.
1 and the surface of the piston rod 02 sliding on the rod packing 08 and the wear ring 11,
Hard chrome plating 17 for wear resistance is applied to two layers on nickel plating 16 for corrosion resistance, so that corrosion of the base material due to intrusion of water and wear due to sliding contact with the packing can be prevented. Can do both.

Further, since the bottom cover 05 and the head cover 06 do not slide relative to the piston rod 02 or the piston 03, only the corrosion resistance against water needs to be ensured. Has ensured corrosion resistance as a one-layer treatment of only the nickel plating 16 from the viewpoint of reduction in manufacturing cost. Also, for the packing groove of the bottom cover 05 and the head cover 06 and the mounting screw portion of the metal fitting, basically only the corrosion resistance needs to be considered, so that only the nickel plating 16 is applied to reduce the cost. Further, the fitting portion 03b between the piston rod 02 and the piston 03 also has no sliding portion,
Only the nickel plating 16 is applied because only the corrosion resistance to water needs to be ensured.

As described above, in the conventional hydraulic cylinder as shown in FIG.
Although stainless steel was used for the piston rod 1 and the piston rod 02, it was expensive. However, in this embodiment, the cylinder tube 01 and the piston rod
For the base metal of No.2, the cost is reduced by using carbon steel parts of hydraulic cylinders that are frequently used in JIS standards or mass-produced by construction machines and have good cutting properties, and nickel plating is applied to places where corrosion resistance is required. 16 treatments,
By applying a two-layer process of nickel plating 16 and hard chrome plating 17 only at places where both corrosion resistance and abrasion resistance are required, corrosion resistance and abrasion resistance at necessary parts are obtained, and a significant cost reduction is achieved. A hydraulic cylinder made is obtained.

Next, a hydraulic cylinder according to a second embodiment of the present invention is configured as follows. In this embodiment, the structure of the hydraulic cylinder and the parts to which nickel plating 16 and hard chrome plating are applied are the same as those in the first embodiment shown in FIGS. As follows.

That is, in this embodiment, the nickel plating 16 is electroless nickel plating, and the plating thickness is 10 to 15 microns. The thickness of the hard chrome plating 17 is set to 20 to 30 microns. As described above, by setting the thickness of the nickel plating 16 to 10 to 15 μm, the finish after the plating process is performed at the time of connecting the fittings, the fastening screw portions, and the pipe fittings to the inflow / outflow ports 12 and 13. Fitting and fastening can be performed without processing. The configuration other than the above is the same as in the first embodiment.

4 and 5 show a third embodiment of the present invention. FIG. 4 is a sectional view of a main part of a cylinder tube and a bottom cover of a hydraulic cylinder, and FIG. 5 is a sectional view of a main part of a head cover and a piston rod. is there.

In FIG. 4, reference numeral 18 denotes a magnet,
The inner surface of the bottom cover 05 is fixed to face the water chamber 21. The magnet 18 is for capturing foreign matter such as metal pieces and rust generated from the inside or mixed from the outside (the inflow / outflow port 13) in the water chamber 21 on one side (right side) of the piston 03. Bottom cover 0
5 is fixed to the inner periphery of the concave portion by screws (not shown) or an adhesive. The surface of the magnet 18 is subjected to surface treatment such as nickel plating or Teflon (registered trademark) coating in order to prevent corrosion in water.

In FIG. 5, 19 is a magnet,
It is fixed to the inner surface of the head cover 06 so as to face the water chamber 22. This magnet 19 captures foreign matter generated from inside or mixed in from outside (inflow / outflow port 12) in the water chamber 22 on the other side of the piston 03.
The magnet 18 is fixed to the head cover 06 by performing the same corrosion-resistant treatment as that of the magnet 18 shown in FIG. Other configurations are the same as those of the first embodiment shown in FIGS. 1 to 3, and the same members are denoted by the same reference numerals.

The present invention is not limited to the hydraulic cylinder as described above, but can be applied to all hydraulic equipment using a corrosive working medium.

[0041]

The present invention is configured as described above.
Nickel plating or two-layer plating of hard chrome plating and nickel plating on a base material based on carbon steel with good workability at a low price makes it possible to produce long members such as cylinder tubes and piston rods. In the component,
A hydraulic cylinder having the required corrosion resistance and abrasion resistance without requiring the use of stainless steel unlike the conventional one, and significantly reducing equipment costs and processing costs as compared with the conventional one. Can be obtained.

According to the fourth aspect of the present invention, since foreign matter is captured by the magnet, it is possible to prevent the occurrence of problems such as burn-in of the sliding portion due to invasion of such foreign matter.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a hydraulic cylinder according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a main part of a cylinder tube and a bottom cover in the first embodiment.

FIG. 3 is a sectional view of a main part of a piston and a piston rod in the first embodiment.

FIG. 4 is an essential part cross-sectional view of a cylinder tube and a bottom cover of a hydraulic cylinder according to a third embodiment of the present invention.

FIG. 5 is a sectional view of a main part of a head cover and a cylinder tube in the second embodiment.

FIG. 6 is a longitudinal sectional view of a conventional hydraulic cylinder.

FIG. 7 is a longitudinal sectional view of a conventional hydraulic cylinder.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 01 Cylinder tube 02 Piston rod 03 Piston 04 Nut 05 Bottom cover 06 Head cover 12, 13 Inflow / outflow port 14 Water pressure pump 15 Switching valve 16 Nickel plating 17 Hard chrome plating 18 Magnet 21, 22 Water chamber

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Manabu Tamura 2-1-1 Shinhama, Arai-machi, Takasago City, Hyogo Prefecture Inside the Takasago Research Laboratory, Mitsubishi Heavy Industries, Ltd. (72) Inventor Shuichi Miyazaki 3000 Tana, Tana, Sagamihara City, Kanagawa Prefecture 3H081 AA03 BB05 CC17 CC20 CC24 DD22 HH10 3H082 AA18 CC05 DB11 DB33 DE09 EE20 4K044 AA02 AB10 BA02 BA06 BB03 BC01 BC02 CA15 CA18

Claims (4)

[Claims] 1. A hydraulic cylinder using a corrosive liquid such as water as a working medium, wherein a component of the hydraulic cylinder is subjected to nickel plating on a portion requiring corrosion resistance, such as a surface contacting the working medium. A hydraulic cylinder characterized in that portions requiring wear resistance, such as sliding portions, are subjected to two-layer plating of nickel plating on a lower layer and hard chromium plating on an upper layer thereof. 2. The hydraulic cylinder according to claim 1, wherein a base material of the component to be subjected to the nickel plating or the two-layer plating is made of carbon steel. 3. The hydraulic cylinder according to claim 1, wherein said nickel plating is applied to a plating thickness of 10 to 15 microns, and said hard chrome plating is applied to a plating thickness of 20 to 30 microns. 4. The hydraulic cylinder according to claim 1, wherein a magnet is fixed to a part of the constituent member of the hydraulic cylinder that faces the liquid chamber in which the working medium is stored.