JPS599785B2 - Hydraulic cylinder with anti-corrosion properties - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic cylinder that has anti-corrosion properties and is free from internal corrosion due to metal ions and anions eluted into an oil fluid as a hydraulic fluid.

Hydraulic cylinders are generally made of metal materials such as cast iron, steel, and aluminum alloys, but in hydraulic cylinders, metal ions such as Cu'' are eluted into the oil fluid inside the cylinder from the piping system. At the same time, various anions are similarly eluted into the oil from the packing, etc., and the metal ions cause corrosion of the inner surface of the cylinder due to the influence of the anions and the small amount of water contained in the oil. There was a risk that pitting corrosion would occur on the inner surface of the cylinder, damaging the piston packing inside the cylinder and causing oil leakage.As an example of such corrosion,
For example, corrosion on the inner surface of brake master cylinders is known. An object of the present invention is to provide a hydraulic cylinder having anti-corrosion properties that does not cause corrosion on the inner surface as described above.

The configuration of the present invention will be explained in detail below.

The present invention is characterized in that an ion trap for trapping corrosive ions eluted into the oil from a piping system connected to the cylinder is provided in the oil passage in the cylinder. The ion trap applied in the present invention varies depending on the form of harmful ions that cause internal corrosion of the cylinder. If corrosion of the inner surface of the cylinder is estimated to progress due to the influence of metal ions (e.g. copper ions) eluted into the oil and a small amount of water contained in the oil, the oil passage in the cylinder Means such as interposing a substance that captures metal ions, such as a cation exchange resin, or providing an electrode opposite to the oil passage and passing an electric current through the electrode to capture the metal ions can be used. Applicable as an ion trap.

In addition, in cylinders made of aluminum alloy, etc., the oxide film formed on the inner surface of the cylinder is decomposed by the anions eluted into the oil, and corrosion progresses due to the metal ions mentioned above. In cases where it is estimated that an ion trap for capturing metal ions as described above can be applied, anions, such as chloride ions, may be eluted into the oil from the piping system. When this happens, a substance that captures anions, such as an anion exchange resin, may be interposed in the oil passage in the cylinder.
The term "oil passage in the cylinder" as used herein includes the oil passage in the cylinder and the oil passage in the piping system near the cylinder connected to the oil passage. Furthermore, the cylinders to which the present invention is applied can be broadly applied to conventionally used cylinders such as double-acting type, single-acting ram type, double-dot type, and telescope type, and there are no restrictions on the purpose of use. Next, the configuration and effects of the present invention will be specifically explained based on the embodiments illustrated in the accompanying drawings.

Figure 1 of the attached drawings shows an example in which a cation exchange resin is interposed in the oil passage near the oil liquid inlet/outlet provided in the cylinder. The oil passage 3 is a tube sheet, which is driven into the oil passage to the cylinder 1. On the inner surface of the tube sheet 3, there is a support part 3a for seating a container 6, which will be described later.
is provided. Reference numeral 4 denotes a pipe connected to the cylinder, and the end thereof is disposed in a D-shape that widens toward the end so as to sit on the tube seat 3.

5 is a bolt for bringing the end of the pipe 4 into close contact with the tube sheet 3 for sealing; 6 is a container filled with cation exchange resin; both ends thereof are formed into a net of approximately 110 mesh; The container 6 is placed on the supporting portion 3a of the tube sheet 3 and is fixed by being pressed by the pipe 4 via the metal fitting 7.

}, C indicates the cation exchange resin filled in the container 6, and the cation exchange resin may be densely packed in the container 6, but in consideration of pressure loss, It is also possible to fill it to the extent that it flows. In the cylinder configured as described above, the oil liquid as the working fluid passes through the ion exchange resin layer when entering and exiting the cylinder, so metal ions (for example, Cu++) eluted into the oil liquid as described above are removed. Since the metal 5 metal ions are captured by the cation exchange resin, they hardly act on the constituent materials of the cylinder, so that corrosion of the constituent materials due to this action is prevented. Become.

After a certain period of time, the cation exchange resin in the container 6 is taken out from the container 6 and recycled and reused, or it is filled with new cation exchange resin and returned to the oil passage. Further, Fig. 2 of the attached drawings shows an example in which a cation exchange resin is interposed in an oil passage in a piping system connected to a cylinder, and 8 in the figure is a connection port to the cylinder; 9 is a connection port to the piping system, 10 is a check valve, 11 is a check valve, 12 is a container filled with cation exchange resin, and its lower end and the part facing the oil passage are a net of about 110 mesh. is formed from. Reference numeral 13 indicates the cation exchange resin filled in the container 12, and reference numeral 14 indicates a bolt for taking the cation exchange resin container 12 in and out of the piping system.

Note that if a bleeder valve is used as the bolt 14, air can be easily vented when the cation exchange resin is regenerated or replaced. If a cation exchange resin is interposed in the oil passage in the piping system of the cylinder as in the example above, the oil will not pass through the cation exchange resin layer when flowing out from the cylinder, especially when it is desired to transmit oil pressure quickly. It's advantageous.

The flow of oil in the piping system is as shown by the arrows in the figure. However, the cation exchange resin layer was interposed in the oil passage in the above embodiment so that all of the oil flowing through the oil passage came into contact with the cation exchange resin. A recess may be provided, the recess may be filled with a cation exchange resin, and the resin may be brought into contact with the oil through a mesh.

In the above example as well, the metal ions (for example, Cu'++') eluted from the piping system into the oil as the working fluid are captured by the cation exchange resin, so corrosion of the cylinder constituent materials by the metal ions is similarly prevented. Ru.

[Brief explanation of drawings]

FIG. 1 of the accompanying drawings shows a sectional view of an embodiment of the present invention in which a cation exchange resin is interposed in the oil passage in the cylinder. FIG. 2 shows a sectional view of an embodiment in which a cation exchange resin is interposed in the oil passage in the piping system connected to the cylinder. In Figure 1, 1... cylinder, 2
...Oil liquid passage, 4... Piping connected to the cylinder, 6... Container filled with cation exchange resin, C... Cation exchange resin. Referring to Figure 2, 8...connection port to the cylinder,
9... Connection port to piping system, 12... Container filled with cation exchange resin, 13... Cation exchange resin.

Claims (1)

[Claims] 1. A corrosion-resistant hydraulic cylinder, characterized in that an ion trap is provided in an oil passage in the cylinder to capture corrosive ions eluted into the oil from a piping system connected to the cylinder.