JP3917897B2 - Impurity removal method and apparatus for swash plate type fluid machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an impurity removal method for a swash plate type fluid machine, which is used in, for example, a drive device for a construction machine, a marine steering machine, etc., and removes metal ions generated in a swash plate type fluid machine using a low viscosity fluid as a working fluid It relates to the device.
[0002]
[Prior art]
A swash plate type fluid machine is often used as a fluid machine used for a drive device of a construction machine, a marine steering machine, and the like. In such a swash plate type fluid machine, for example, in a fluid pump, a cylinder block fixed to a pump shaft is rotated by a driving source such as an engine or an electric motor so that the cylinder block can reciprocate in a plurality of cylinders perforated in the cylinder block. The accommodated piston is configured to reciprocate in the cylinder by the sliding rotation with the swash plate arranged so that the inclination angle can be adjusted, and pump the working fluid.
Conventionally, in such swash plate type fluid machines, hydraulic machines using a working fluid mainly composed of mineral oil have been widely used. However, due to problems such as environmental pollution due to leakage of hydraulic oil and the risk of fire during work in recent years. Development and commercialization of fluid machinery using working fluids whose main components are low-viscosity fluids other than mineral oil such as water are being promoted.
[0003]
FIG. 4 shows a cross-sectional view of a swash plate type hydraulic piston pump using water disclosed in JP-A-8-247021 as a working fluid. Such a hydraulic piston pump includes a case 011 provided with an end plate 012 and a gradle 013 at both ends to form a water chamber inside, a shaft 01 penetrating through them and supported via a bearing plate 02, and a spline on the shaft 01. The valve plate 05 is joined through the valve plate 05 and joined to the end plate 012, the plurality of cylinder blocks 04 sliding with the valve plate 05, the piston 06 reciprocating in the cylinder block 04, and the piston through the shoe 015 06 and a swash plate 014 having a thrust plate 07 that slides and rotates.
[0004]
In the swash plate hydraulic piston pump, the cylinder block 04 and the shoe 015 are formed of a copper alloy, and the valve plate 05, the piston 06, and the thrust plate 07 are formed of a ceramic member such as SiC or Si ₃ N ₄ .
In this way, the use of copper alloy on one side of the sliding member and ceramic on the other side greatly improves the sliding characteristics of the sliding part and should be used at the same high pressure as a hydraulic pump that uses mineral oil as the working fluid. This makes it possible to manufacture a hydraulic pump that does not cause seizure or wear of the sliding surface.
[0005]
[Problems to be solved by the invention]
However, when a low-viscosity fluid such as water is used as the working fluid as in the prior art, metal ions are eluted by immersing the metal material used for the sliding member or the like in the fluid for a long time, and the case 011 Not only the inside but also the sliding surface between the piston 06 and the cylinder block 04, the sliding surface between the thrust plate 07 and the shoe 015, etc., metal may be deposited and sandwiched between the sliding surfaces to damage the parts of the device. There is.
In particular, when tap water, which is considered to be most frequently used because it is cheap and easily available, is used as the working fluid, the precipitation of metal is further promoted by the chlorine ions contained in the tap water, and the metal powder It becomes a state where impurities such as the body are easily generated, and it is necessary to perform maintenance frequently.
Therefore, in view of the problems of the prior art, the present invention can remove impurities such as metal powders reliably and efficiently with a simple device, and can reduce the maintenance frequency. It is an object of the present invention to provide a method and apparatus for removing impurities.
[0006]
[Means for Solving the Problems]
Accordingly, in order to solve such a problem, the present invention provides a swash plate type in which the swash plate built in the housing and the piston in the cylinder reciprocate by relative movement while sliding and rotating. In fluid machinery,
In order to remove metal ions eluted in the working fluid in the fluid machine, a floating electrode is formed in at least a part of the path of the casing and the discharge pipe for the working fluid, and a negative voltage is applied to the floating electrode. Application is made to deposit the eluted metal ions as a metallic substance.
[0007]
In general, for the swash plate type fluid machine, for example, a metal material such as steel is used for the casing and the discharge suction pipe, and a metal material such as a copper alloy is used for the cylinder, and a conductive material is often used. This invention is such that an insulating material such as a resin insulating material is interposed between at least a part of the housing and the part formed by the conductive member of the discharge pipe for working fluid and the other part. It is electrically isolated and used as a floating electrode.
[0008]
Then, by applying a negative voltage to the floating electrode, the cathode reaction is promoted to deposit and supplement metal ions contained in the working fluid. That is, by setting the floating electrode to a negative potential, metal ions are attracted by the Coulomb force and adsorbed and deposited.
In this way, floating electrodes are formed in parts other than sliding parts such as pistons, cylinders, and swash plates, so that metal is not caught in the sliding parts and damaged, and maintenance frequency can be reduced. It is said.
[0009]
And like invention of Claim 2, it is preferable to form a floating electrode in at least one part of the said housing | casing, and to deposit a metal substance on the inner wall of this housing | casing.
According to this invention, by applying a negative voltage to the casing insulated from the operating part including the cylinder and the piston, the metal ions existing near the sliding part are attracted to the casing to be deposited and supplemented. Can do. At this time, since the floating electrode is formed near the sliding portion, the metal ions generated in the housing can be removed with high efficiency.
The supplemented metal substance may be removed during maintenance of the fluid machine.
[0010]
According to a third aspect of the present invention, a floating electrode is formed on at least a part of a path of the discharge suction pipe to deposit a metal substance on the pipe, and the deposited metal substance is removed from the discharge suction pipe. May be removed.
In this invention, a negative voltage is applied using a pipe connected in an insulating manner as a floating electrode to deposit a metal substance on the pipe. Thereby, the deposited metal substance can be easily removed.
[0011]
The invention according to claim 4 is characterized in that the working fluid is water.
In this way, by using water as the working fluid, it is possible to ensure the safety of such a fluid machine without any fear of polluting the environment even if the working fluid leaks, and without causing a fire or the like. Can do. In addition, the use of water makes it easy for metal ions to be generated, but this can be removed by the invention as described above, and inexpensive water such as tap water can be used, resulting in cost reduction. It becomes possible.
[0012]
The invention according to claims 5 to 7 is an invention relating to an apparatus for suitably carrying out the invention, and the invention according to claim 5 is a swash plate built in a housing, and is slidably rotated with respect to the swash plate. However, in a swash plate type fluid machine having a piston in a cylinder that reciprocates by its relative movement,
The floating electrode is formed in at least a part of the passage of the casing and the working fluid discharge / intake pipe, and a DC power source is provided outside the casing, and a negative electrode of the DC power source is connected to the floating electrode, thereby The metal ions eluted in the fluid are deposited on the floating electrode as a metal substance.
[0013]
The invention according to claim 6 is characterized in that the casing and the operating portion including the cylinder and the piston are insulated, and the casing is used as a floating electrode.
Furthermore, the invention described in claim 7 is characterized in that a part of the path of the discharge suction pipe is a detachable connecting pipe, and the connecting pipe is insulated from other pipes to form a floating electrode.
The invention according to claim 8 is characterized in that a filter is interposed on the discharge side of the connecting pipe, and the solid matter contained in the working fluid is supplemented by the filter.
In addition, as described in claim 9, these inventions can be suitably used in a fluid swash plate machine in which the working fluid is water.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Not too much.
FIG. 1 is a cross-sectional view of a swash plate hydraulic pump according to a first embodiment of the present invention, taken along a pump axis, FIG. 2 is a cross-sectional view of a second embodiment showing another embodiment of FIG. 1, and FIG. It is the Z section enlarged view of the swash plate concerning embodiment of invention.
[0015]
1 to 3, 1 is a pump shaft connected to a drive source (not shown) such as an engine or an electric motor, and is rotated, 2 is a casing, 3 is a base plate, 4 is an end plate, and 5 is the pump shaft. 1 is a cylinder block that is rotationally driven in synchronism with 1.
A plurality of cylinders 6 are formed in the cylinder block 5 at equal intervals in the circumferential direction, and pistons 7 are fitted in the cylinders 6 so as to be able to reciprocate. A bush (not shown) may be press-fitted into the cylinder 6 and the piston 7 may be fitted into the bush so as to be capable of reciprocating.
[0016]
Reference numeral 8 denotes a swash plate disposed at the tip of the piston 7, and the swash plate angle can be adjusted by a swash plate angle adjusting device 80 shown in FIG. That is, as shown in FIG. 3, each adjusting device 80 of the swash plate rotates the lever 08a by a piston 08c reciprocating in the cylinder 08b, and the swash plate shaft 08 fixed to the end of the lever 08a is shown in FIG. The slant angle is changed by turning like the U arrow. Reference numeral 14 denotes a thrust plate constituting the inclined surface of the swash plate 8 so that the slipper 15 connected to the head of the piston 7 slides and rotates on the thrust plate 14 in the circumferential direction via a roller bearing 28. It is configured.
The cylinder block 5, the cylinder 6 and the slipper 15 are preferably formed of a copper alloy material, and the piston 7 and the thrust plate 14 are preferably formed of a ceramic member such as SiC or Si ₃ N _4. .
[0017]
Reference numeral 11 denotes a valve plate which is disposed on the discharge suction system piping side of each cylinder 6 and is fixed to the end plate 4. The valve plate 11 has an eyebrow-shaped suction hole located on the suction pipe 20 side and a discharge hole located on the discharge pipe 21 side, and the respective pipes and the holes communicate with each other.
Reference numerals 12 and 13 denote a bearing on the base plate side and a bearing on the end plate side that support the pump shaft 1. Reference numeral 16 denotes an oil seal, and reference numeral 17 denotes a casing which is constituted by the base plate 3 and end plate 4 at both ends and the casing 2 and forms a pump chamber 19.
[0018]
In the first embodiment, the casing 2 is electrically isolated by interposing an insulating material 27 between the casing 2, the base plate 3 and the end plate 4. In the first embodiment, the casing 2 is limited to a conductive material.
In the first embodiment, a DC power source 24 such as a battery is provided, and a cathode of the DC power source 24 is connected to a part of the casing 2 to form a floating electrode.
[0019]
The operation of the swash plate hydraulic pump 40 will be described. When the pump shaft 1 is rotationally driven by a drive source (not shown), the cylinder block 5 is integrated with the cylinder 6, the piston 7 and the slipper 15 connected thereto. Rotate. By this rotation, the slipper 15 slides and rotates through a spherical bearing formed on the thrust plate 14, and thereby the piston 7 reciprocates in the cylinder 6 while rotating together with the cylinder block 5.
[0020]
When the piston 7 is located on the suction pipe side, the oil supply / discharge hole of the cylinder 6 communicates with the suction hole of the valve plate 11 and water is sucked from the suction passage 9. On the other hand, when the oil supply / discharge oil hole of the cylinder 6 is located on the discharge pipe side, it communicates with the discharge hole of the valve plate 11, and the water in the cylinder 6 is pumped to the discharge passage 10 by the piston 7.
Thus, the working fluid is pumped by the power transmitted from the drive source.
[0021]
When the swash plate hydraulic pump 40 is operated, part of the working fluid supplied from the suction passage 9 leaks from the sliding surface between the piston 7 and the cylinder 6 when the piston 7 reciprocates. The leaked water accumulates in the casing 17 and scatters in the casing 17 by the rotation of the pump. The leaked water contains copper ions eluted from the cylinder block 5 and the cylinder 6.
Accordingly, when a negative voltage is applied to the casing 2 (floating electrode) by the DC power supply 24 in synchronization with the operation of the swash plate hydraulic pump 40, the copper ions eluted in the pump chamber 19 are transferred to the casing 2. It will be deposited as a precipitate 25 on the surface of the (floating electrode).
[0022]
Note that the DC power source 24 is sufficient to allow a weak current to flow through the casing 2, and is preferably an inexpensive and easy to handle battery such as a dry battery.
Thereby, impurities such as metal powder deposited in the pump chamber 19 enter the sliding surface between the cylinder 6 and the piston 7 or the sliding surface between the slipper 15 and the thrust plate 14 to damage the device. The possibility of damage is reduced, and the maintenance frequency can be reduced.
[0023]
FIG. 2 shows a second embodiment of the present invention. In the figure, the configuration in the housing 17 and the configuration of the suction / discharge system piping are substantially the same as those in the first embodiment. That is, a shaft pump 1 connected to a driving source and rotating, a piston 7 including a slipper 15 which is integrated with the shaft pump 1 and slidably rotates on a thrust plate 14, and the piston are reciprocally fitted. The cylinder 6 and the cylinder block 5, the suction pipe 20 and the discharge pipe 21 are configured to discharge the pumping fluid by the same action as in the first embodiment.
[0024]
A connecting pipe 22 is disposed between the discharge pipe 21 and the casing 17 with an insulating material 23 interposed. In the second embodiment, a cathode of a DC power source 24 is connected to the connecting pipe 22. Floating electrode. Thereby, the copper ion contained in the water discharged | emitted by the pump chamber 19, the discharge channel | path 10, and the discharge piping 21 side can be drawn near, and can be deposited as this deposit 25 in this connection pipe | tube 22 (floating electrode).
According to the second embodiment, since the connecting pipe 22 is configured to be detachable, the precipitate 25 can be easily removed.
Further, a filter 26 may be interposed between the discharge pipe 21 and the connecting pipe 22, whereby the precipitate 25 and other impurities can be removed by filtration.
[0025]
【The invention's effect】
As described above, according to the present invention, the floating electrode is formed in a portion other than the sliding portion such as a piston, a cylinder, and a swash plate, thereby preventing the metal from being sandwiched and damaged by the sliding portion. As a result, the maintenance frequency can be reduced.
In addition, by using the casing present near the sliding portion as a floating electrode, metal ions present in the fluid machine can be removed with high efficiency.
Further, by applying a negative voltage using the insulated connection pipe as a floating electrode and precipitating a metal substance on the pipe, the deposited metal can be easily removed with a simple structure.
[0026]
Furthermore, by using water as the working fluid, it is possible to safely use such a fluid machine without fear of polluting the environment even if the working fluid leaks out, and without causing a fire or the like. . Further, the use of water makes it easy for metal ions to be generated, but this can be removed by the invention as described above, and the cost can be reduced by using inexpensive water such as tap water. .
[Brief description of the drawings]
FIG. 1 is a sectional view taken along a pump shaft center line of a swash plate type hydraulic pump according to a first embodiment of the present invention.
FIG. 2 is a sectional view of a second example showing another embodiment of FIG. 1;
FIG. 3 is an enlarged view of a Z portion of the swash plate according to the embodiment of the present invention.
FIG. 4 is a cross-sectional view taken along a pump axis of a conventional swash plate hydraulic pump.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Pump shaft 2 Casing 6 Cylinder 7 Piston 8 Swash plate 9 Suction passage 10 Discharge passage 17 Housing | casing 19 Pump chamber 20 Suction piping 21 Discharge piping 22 Connecting pipe 23, 27 Insulation material 24 DC power supply 25 Precipitate 26 Filter 40 Swash plate water pressure pump

Claims (9)

In the swash plate type fluid machine in which the swash plate built in the housing and the piston in the cylinder reciprocate by sliding relative to each other while sliding and rotating,
In order to remove metal ions eluted in the working fluid in the fluid machine, a floating electrode is formed in at least a part of the path of the casing and the discharge pipe for the working fluid, and a negative voltage is applied to the floating electrode. An impurity removing method for a swash plate type fluid machine, wherein the eluted metal ions are deposited as a metal substance by applying the metal ions. The impurity removal method according to claim 1, wherein a floating electrode is formed on at least a part of the casing to deposit a metal substance on the inner wall of the casing. 2. A floating electrode is formed on at least a part of a path of the discharge / intake pipe to deposit a metal substance on the pipe, and the deposited metal substance is removed by removing the discharge / intake pipe. For removing impurities in swash plate type fluid machinery. 2. The impurity removal method for a swash plate type fluid machine according to claim 1, wherein the working fluid is water. In a swash plate type fluid machine comprising a swash plate built in a housing and a piston in a cylinder that reciprocates by relative movement while sliding and rotating with respect to the swash plate,
The floating electrode is formed in at least a part of the passage of the casing and the working fluid discharge / intake pipe, and a DC power source is provided outside the casing, and a negative electrode of the DC power source is connected to the floating electrode, thereby An apparatus for removing impurities of a swash plate type fluid machine, wherein metal ions eluted in a fluid are deposited on the floating electrode as a metal substance. 6. The impurity removing apparatus for a swash plate type fluid machine according to claim 5, wherein said casing is insulated from an operating portion including said cylinder and piston, and said casing is used as a floating electrode. 6. The impurity removing device for a swash plate type fluid machine according to claim 5, wherein a part of the path of the discharge / intake pipe is a detachable connecting pipe, and the connecting pipe is insulated from another pipe to form a floating electrode. 8. The impurity removing apparatus for a swash plate type fluid machine according to claim 7, wherein a filter is interposed on the discharge side of the connecting pipe, and the solid matter contained in the working fluid is supplemented by the filter. 9. The impurity removing apparatus for a swash plate type fluid machine according to claim 5, wherein the working fluid is water.

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