JP2010534788A - Lubricator and hydraulic piston for engine cylinder lubrication - Google Patents

Abstract

  For example, a hydraulic lubrication apparatus and a hydraulic piston for a quantitative supply system for cylinder lubricating oil in a marine engine will be described. This lubrication device is distributed such that at least one hydraulic piston 106 that can be pressurized by hydraulic oil, a plurality of metering pistons 21, and one side is in contact with the metering piston 21 and the other side operates the metering piston. And a distribution plate 7 in contact with at least one hydraulic piston 106 for displacing the plate. The hydraulic piston 106 has an internal bore B extending in the displacement direction of the hydraulic piston, and this bore is provided with a hollow insert piston E in contact with a jet port H for hydraulic oil. An insert C5E including an insert cylinder C is provided. This allows the hydraulic piston 106 to move faster and improves pressure and flow conditions, resulting in significant improvements in pressure and flow within the spray nozzle, resulting in the performance of the lubrication system. Will improve.

Description

  The present invention relates to a hydraulic lubrication device for a metered supply system for cylinder lubricating oil, for example in a marine engine, which has at least one hydraulic piston and is hydraulically driven to supply lubricating oil. . The device may be pressurized with hydraulic fluid and further includes a plurality of metering feed pistons and at least one for displacing the distribution plate so that one side is in contact with the metering feed piston and the other side operates the metering feed piston. And a distribution plate in contact with the two hydraulic pistons.

  The invention also relates to a hydraulic piston for such a lubrication device.

  In the conventional cylinder lubrication system, mainly in the case of a large two-cycle diesel engine, various types of lubrication are performed at a certain point in each of a single cylinder or a plurality of cylinders, that is, lubricated at appropriate time intervals. Two or more central lubrication devices are used which lubricate by supplying the part of the oil that is under pressure through the connection lines individually up to the point. See, for example, EP0 678 152. This suitable time interval may typically be when the piston ring is in a position facing its associated lubrication point during a compression stroke in which the piston is moving upward.

  Lubricators have traditionally been installed in close proximity to each cylinder and designed as a pumping unit at different locations on the cylinder wall, and a lubrication point in the form of an oil injection nozzle. Connected to. Each pump unit includes a plurality of regipro pumps, which supply oil to various lubrication points and are driven by a common rotation control shaft provided with a cam. When the control shaft rotates, the cam with the pressing head acts on each axially displaced piston that is spring-biased in the direction toward the control shaft, and as a result, when these pistons rotate the control shaft. And reciprocating to drive the piston of the regipro pump.

  Over the years, the lubrication system has been operated under conditions where the discharge pressure from the piston pump is not so high, which is due to the return stroke upwards of the engine piston, i.e. during the compression operation but ignition combustion This is because it was the established standard that oil was injected into the cylinder before the subsequent power stroke. For this reason, the lubrication apparatus had to be operated with an injection pressure or pump pressure of about 10 bar (1 MPa).

  In recent years, it has been proposed to improve lubrication efficiency by injecting oil through a pressurized spray nozzle in order to perform oil mist lubrication during the upward movement of the piston. In this case, however, the oil is subjected to a much higher pressure, for example up to 100 bar (10 MPa) or more, for fine atomization via the spray nozzle.

  In addition, in recent years, electronic-based diesel engines have tended to be more widely manufactured, and such engines remove the mechanical drive previously used to drive mechanical lubrication devices.

  Thus, the lubrication locations include oil injection nozzles and / or pressurized spray nozzles as referred to herein.

  In either system, the control shaft is driven through a direct or indirect mechanical coupling with the engine crankshaft, so that the engine crankshaft is powered at the same time as providing power to operate the pump. And synchronization with the control shaft of the lubrication device.

  The pump unit comprises, for example, a box-shaped device housing from which connecting pipes extend, for example to 6-24 lubrication points of the associated engine cylinder.

  Conventionally, the piston is driven by an actuating cam / rocker arm on a penetrating control shaft that rotates synchronously with the crankshaft of the engine. The piston is spring biased in the direction of the actuation cam. A set screw is provided that defines the extreme position of the associated actuation cam. This set screw may be actuated to determine the individual actuation strokes of the pistons, thereby determining the associated discharge rates of the individual piston pumps.

  Since cylinder lubricant is generally supplied in a fixed amount once for each revolution of the engine, the only way to adjust this fixed supply is to change the stroke of the pump. A system for this purpose is described, for example, in Danish Patent Application No. 4998/85. This system is operated by a cam disk mechanism for adjusting the pump stroke based on the engine load. The load dependence can be changed only by replacing the cam disk with another cam disk having a different transfer function.

  It has also been proposed to adjust the pump stroke with a controllable motor such as a step motor. This is used for point lubrication, but is difficult to carry out in connection with conventional lubrication devices. Such a system is disclosed, for example, in international patent application WO02 / 35068A1.

  Furthermore, from DE 28 27 626, a lubricating system based on lubricating oil metered in at predetermined time intervals through an opening in a cylinder wall is known. Here, there is no indication of the possibility of carrying out the stepless control of the quantitative supply at the individual lubrication points.

  Furthermore, systems of the type mentioned in the introduction are known from GB834533A, DK173512B1 or CH6733506A5, in which a hydraulic cylinder acts on a plurality of metering pistons via distribution plates or similar structures. In such a design, there is one hydraulic cylinder for activation. For this reason, when this hydraulic cylinder fails, the operation of all the fixed supply pistons is interrupted.

  In connection with conventional cylinder wall lubrication, a simple spring-loaded check valve has been conventionally used that can counteract the internal pressure in the cylinder but loses slightly higher external injection pressure. . However, in the case of pressurized spray injection, the valve system should be opened only when much higher oil pressure is applied so that oil injection can enjoy the features of pressurized spray injection from the beginning. Is desired and required.

  So far, in Danish patent application PA2005 01629, a hydraulically driven lubrication device of the type mentioned in the introduction and a method for quantitatively supplying cylinder lubricating oil have been proposed. The principle described in this named patent application makes it possible to perform cylinder lubrication in such a way that flexible electronic control and stepless central control of the metered supply to the lubrication point is realized. Furthermore, accurate and simple timing control can be performed. The system also describes the use of distribution plates.

  In this hydraulic system, it is desirable to use a cross-sectional area ratio of at least one hydraulic piston and a metering piston. Therefore, DK173512B1 shows that the hydraulic piston has a cross-sectional area that is 4 times, preferably 6 to 15 times the cross-sectional area of the metering piston, in order to establish the pressure state required in the lubricating oil. Has been. A large area ratio is not preferable because an extra space is required.

  In connection with the testing of these prior art lubrication devices, the lubrication oil is delivered at a sufficient speed when a lubrication device of the type, for example as described in EP 1 129 275, is used in the spray nozzle. The problem of being unable to do so was observed. This is in particular the pursuit of a solution that realizes a rapidly operating cylinder lubrication system that can provide an adequately fast and accurate metering at the lubrication point inside the liner. Was observed in connection with a lubrication device of the type shown in DK173512B1. Experiments were carried out with increasing pressure in the hydraulic system, but no obvious effect was seen. The reason was, among other things, that the solenoid valves in the system did not have sufficient capacity. This problem cannot be solved by simply replacing the solenoid valve, because the solenoid valve cannot be easily replaced.

  It would be desirable to solve the problem of using efficient pressurized spray nozzles within existing and newly developed cylinder lubrication systems.

EP 0678152 International Publication WO02 / 35068A DE2827626 GB83453A DK173512B CH6733506A DK173512B EP1129275 EP1129275

  The object of the present invention is to show a hydraulically driven lubrication device which alleviates the above-mentioned drawbacks and makes it possible to provide a very reliable and inexpensive system, in which a risk of malfunction is present. It is possible to feed the lubricating oil at a sufficiently fast speed at high operating pressures to eliminate or reduce the performance.

  According to the invention, this object is achieved by a hydraulic lubrication device of the type mentioned in the introduction. In this device, the hydraulic piston has an internal bore extending in the displacement direction of the hydraulic piston, the internal bore is provided with an insert, and the insert is a hollow that comes into contact with the jet port for hydraulic oil. It is characterized by comprising an insert cylinder in which an insert piston is disposed.

  The hydraulic piston according to the invention likewise has an internal bore in which the hydraulic piston extends in the displacement direction of the hydraulic piston, and a hollow insert that is in contact with the outlet for hydraulic oil. It is characterized by comprising an insert including an insert cylinder in which a piston is provided.

  The present invention may be used in connection with the device disclosed in the above-mentioned patent publication. In this case, a hydraulic lubrication device including a distribution plate is used.

  However, the present invention is connected with another type of lubrication device and another method in which hydraulic lubrication using a hydraulic piston is applied to act on an injection unit having a metering piston for cylinder lubricant Here, one or more hydraulic pistons act on the distributor plate used to actuate the metering piston.

  From the above, it has been found that changing the diameter of the insert on the hydraulic piston allows the hydraulic piston to move faster, thereby greatly improving the pressure and flow conditions, As a result, significant improvements in pressure and flow within the spray nozzle are realized, improving the performance of the lubrication system. The modified hydraulic piston also eliminates the need for excessive flow capacity in the solenoid valves in the system to achieve optimal pressure and flow for the spray nozzle. This is accomplished in a technically simple manner that can be adapted to existing systems by simply modifying one or more hydraulic pistons used.

  As a result, the amount of hydraulic oil required to operate the fixed amount supply piston is reduced, and it is realized that the lubricating oil is supplied to the spray nozzle in a large amount and at high speed.

  According to another embodiment, the lubricating device and the hydraulic piston according to the invention are characterized in that the insert piston is screwed into a bore through which hydraulic oil is supplied. As a result, the hydraulic fluid is sent to a reduced cross-sectional area in the bottom of the insert piston, resulting in a tighter connection.

  According to another embodiment, the lubricating device and the hydraulic piston according to the invention are characterized in that the ratio of the cross-sectional area of at least one hydraulic piston to the cross-sectional area of the metering piston is less than 7, preferably less than 5. To do.

As a specific example, a hydraulic piston of the type shown in FIGS. 2 and 3 can be modified as follows:
− Standard hydraulic piston:
Hydraulic piston: φ31mm Fixed supply piston: 5 × φ3.5
Ratio = 31 ² /(5×3.5 ² ) = 15.7
-Modified hydraulic piston:
Hydraulic piston insert: φ16mm Fixed amount supply piston: 5 × φ3.5
Ratio = 16 ² /(5×3.5 ² ) = 4.2

  By making such changes, the hydraulic piston according to the present invention can be used to increase the speed of the lubricant pressure increase and pressure relief cycle for the spray nozzle by 50%.

  According to another embodiment, the lubricating device and the hydraulic piston according to the invention are characterized in that a drain for hydraulic oil is provided between the outside of the insert piston and the bore of the hydraulic piston. Since the leaked oil can be guided out via the hydraulic piston, the hydraulic oil does not accumulate inside the chamber in which the hydraulic piston is located. When hydraulic oil may accumulate inside the chamber, it means that the hydraulic oil acts on the entire cross-sectional area inside the chamber. The required flow rate will be reduced and will not be there, which is based on achieving the technical advantages of the present invention.

  According to another embodiment, the lubrication device and the hydraulic piston according to the invention are such that the bore of the hydraulic piston, the insert cylinder, and the insert piston are circular in cross section, which are arranged concentrically about the central axis It is characterized by that. This is a very simple embodiment that is easy to manufacture.

According to another embodiment, the lubricating device according to the invention comprises a metering system,
-A supply line and a return line connected to the lubrication device via one or more valves for supplying hydraulic oil;
A central hydraulic oil supply pump, each connected via a supply line to a hydraulic cylinder having a hydraulic piston and capable of receiving the pressure of the hydraulic oil;
-A number of injection units connected to the individual metering cylinders with a metering piston, corresponding to the number of cylinders in the engine;
-Characterized in that it has a supply line for cylinder lubricant.

  Thereby, the required hydraulic oil and lubricating oil are reliably supplied. Note that oil from the same source can be used because the lubricating oil and the oil for operating the hydraulic piston are of the same type.

  The present invention will now be described in more detail with reference to the accompanying drawings.

1 is a schematic overall view of a system comprising a plurality of lubricating devices according to the present invention. FIG. 3 is a schematic view of a second embodiment of a system comprising a lubricating device according to the invention. 1 is a longitudinal sectional view of an embodiment of a cylinder lubrication unit that can form part of a lubricating device according to the present invention. FIG. 2 is a diagram of another embodiment of a lubrication device according to the present invention used in the system shown in FIG. 1.

  FIG. 1 shows a system made in accordance with the specification shown in PCT / DK2007 / 000364.

  FIG. 1 schematically shows four cylinders 250 with eight injection nozzles 251 on each cylinder. A lubricator 252 is connected to the central computer 253 by a local control unit 254, which is usually for each single lubricator 252. Lubricator 252 is adapted to a shape as described in detail below.

  The central computer 253 is coupled in parallel to another control unit 255 that constitutes a backup of the central computer. Also provided is a monitoring unit 256 for monitoring the pump (which may be a hydraulic pump or a hydraulic station), a monitoring unit 257 for monitoring the load, and a monitoring unit 258 for monitoring the position of the crankshaft. Yes.

  In the upper part of FIG. 1, a hydraulic station 259 having a motor 260 for driving a pump 261 in a hydraulic oil tank 262 is shown. The hydraulic station 259 further includes a cooler 263 and a filter 264. System oil is pumped through supply line 265 and reaches the lubricator via valve 220. The hydraulic station is also connected to a return line 266 that is also connected to the lubrication device via a valve.

  Lubricating oil is sent from a lubricating oil supply tank (not shown) to the lubricating device 252 via a line 267. Lubricating oil is sent from the lubricating device to the injection nozzle 251 via the line 110.

  FIGS. 2 and 3 show a system of the type whose principle is known from the description of Danish patent specification 173512.

  FIG. 2 shows a cylinder lubrication system illustrating two cylinders 2. Each cylinder 2 is provided with four lubrication points 6 including an injection unit 6 '. Each of the lubrication units 6 ′ is connected via a connection line 29 to a central lubrication device 30 connected to the control valve 31. The control valve 31 is connected to the electronic control unit 9 via the wiring 32. Furthermore, a pressure control unit 33 connected to the electronic control unit 9 via wires 34 and 35 and connected to the cylinder lubrication unit 30 via lubricating oil supply lines 36 and 37 is shown.

  The cylinder lubrication unit 30 is shown in more detail in FIG.

  The cross-sectional view of FIG. 3 shows that the central cylinder lubrication unit 30 includes a supply gate 38 for lubricating oil. The central cylinder lubrication unit 30 also has a return gate 39 for drive oil, which in the illustrated embodiment is the same as the lubrication oil. The control valve 31 is connected to a valve 40 that adjusts the supply and discharge of oil. The cylinder lubrication unit 30 has a hydraulic piston 41 having a flange 42. As shown in FIG. 2, each of the flanges 42 is engaged with a fixed amount supply piston 43 that supplies lubricating oil to the lubricating portion 6 through the gate 44 and the connection line 29.

  That is, FIG. 3 shows a hydraulic piston 41 having a flange 42 that functions as a distribution plate, which acts on a plurality of metering supply pistons 43.

  The unit 30 has an adjustable stop element 45 that determines the operating distance of the hydraulic piston 41. The stopper element 45 sets the stroke of the hydraulic piston 41, thereby setting the stroke of the fixed amount supply piston 43 that functions as a fixed amount supply pump.

  The compression spring 46 preloads the hydraulic piston 41 in the direction of the starting position. The adjustable stop element 45 is screwed into a thread 47 in the end portion 48 of the unit. By screwing the adjustable stopper element 45, the stroke of the hydraulic piston 41 is limited, thereby limiting the amount of lubricating oil discharged from the metering piston 43. Thus, the adjustable stop element 45 functions as a device for adjusting the stroke of the regipro pump. The adjustable stop element 45 is connected to an electronically controlled adjusting means 49. The adjusting means 49 is connected to the central electronic control unit 9 via the wiring 50. As a result, electronic control of the stroke of the regipro pump is possible, and stepless central control of the quantitative supply at the individual lubrication points 6 can be performed in a flexible manner.

  The hydraulic piston 41 has a cylindrical shape and is disposed in the chamber A. This chamber A functions as a cylinder in which the piston is displaced in the conventional lubricating device. The hydraulic piston 41 has a central bore B in which an insert cylinder C is attached. The insert cylinder C is hollow and has an internal bore D in which the insert piston E is accommodated and ends in a closed bottom F. The insert piston E is mounted in the opening H via a thread thread G in order to supply hydraulic oil into the chamber A. The insert piston E has an internal bore through which hydraulic fluid flows and acts on the bottom F in the insert cylinder. As a result, the hydraulic piston is displaced, and thereby the flange 42 is displaced, and the fixed amount supply piston is operated. The hydraulic piston 41 has a drain opening J and diffuses leaked oil between the space between the outside of the insert cylinder C and the bore B and the outside through the drain opening J. be able to. This prevents oil from accumulating in the chamber A behind the hydraulic piston 41.

  The lubrication apparatus shown in FIG. 4 is assembled on a bottom 110 to which electromagnetic valves 115 and 116 for starting the apparatus are attached. On the side of the bottom 110, there are provided a threaded joint 142 for the system hydraulic pressure supply and a threaded joint 143 for the system hydraulic pressure return to the tank.

  The drive oil can be supplied through two solenoid valves, one is a primary solenoid valve 116 and the other is a secondary solenoid valve 115.

  In the initial position, the primary solenoid valve 116 is activated. This causes drive oil to be guided from the associated supply screw joint 142 to the primary solenoid valve 116, into the device via the switching valve 117, and through the distribution passage to the associated hydraulic piston group.

  If the primary solenoid valve 116 is broken, the secondary solenoid valve 115 can be automatically connected. This connection is made by operating the secondary solenoid valve 115.

  This pressurizes the associated distribution passage. This pressure displaces the switching valve 117 to the right and interrupts the connection between the primary solenoid valve 116 and the associated distribution passage. Thereby, pressure is removed from the hydraulic piston connected to the electromagnetic valve 116.

  By activating the secondary solenoid valve 115, the associated distribution passage and the associated hydraulic piston are pressurized. Thereby, the distribution plate 7 is then driven by the oil guided into the device via the secondary electromagnetic valve 115.

  The switching valve 117 can be equipped with a spring 119. When there is no supply pressure through the secondary solenoid valve, this spring automatically returns the switching valve 117 to the initial position described above.

  The switching valve can be equipped with a restrictor that delays the return of the switching valve. Thereby, it is possible to avoid or restrict the switching valve 117 from moving in the front-rear direction between operations. In FIG. 4, such a restriction is defined by a groove formed between the drain pin 118 and the switching valve 117.

  Independence between the solenoid valves is ensured when each solenoid valve is connected to a separate group of hydraulic pistons. When switching between the primary solenoid valve 116 and the secondary solenoid valve 115, the switching valve 117 removes the pressure from the primary group of the hydraulic piston, so that the secondary solenoid valve is shut off even when the primary solenoid valve is shut off. The solenoid valve 115 can be actuated.

  Reference numeral 121 denotes a blanking screw.

  Reference numeral 122 denotes a combination of a blocking screw and an end stopper. In this combination, a part functions as an end stopper of the claw 120 of the switching valve 117 and a part has a sealing function via a packing (not shown).

  A distribution plate 7 is present on the hydraulic piston 106. Here, the distribution plate is shown as a design composed of two parts, an upper distribution plate member 125 and a lower distribution plate member 123. The fixed amount supply piston 21 is attached inside or on the upper distribution plate member 125. In devices where different oils are used for drive and lubrication, there is a piston packing 124 between the upper distributor plate member and the lower distributor plate member. In principle, it may be sufficient to use one type of oil as drive oil and lubricating oil.

  Each hydraulic piston 106 is cylindrical and is disposed in the chamber A. This chamber A functions as a cylinder in which the piston is displaced in the conventional lubricating device. The hydraulic piston 106 has a central bore B in which an insert cylinder C is mounted. The insert cylinder C is hollow and has an internal bore D in which the insert piston E is accommodated and ends in a closed bottom F. An insert piston E is mounted in the opening H via a thread G for supplying hydraulic oil into the chamber A. The insert piston E has an internal bore through which hydraulic fluid flows and acts on the bottom F in the insert cylinder. As a result, the hydraulic piston is displaced, and thereby the distribution plate 7 is displaced, and the fixed amount supply piston 21 is operated. The hydraulic piston 106 has a drain opening J, and can leak leaked oil between the space between the outside of the insert cylinder C and the bore B and the outside through the drain opening J. This prevents oil from accumulating in the chamber A behind the hydraulic piston 106.

  Around the fixed amount supply piston 21, there is a common return spring 109 for returning the piston 21 after the supply pressure applied to the hydraulic piston 106 is shut off. Around the return spring 109 is a small lubricant container 147 whose outer boundary is defined by the base block 111. Lubricating oil is supplied via a separate threaded joint with packings 138 and 139. This device can optionally be equipped with a vent screw with packing.

  A cylinder block 112 is positioned on the base block 111, and a fixed amount supply piston 21 is disposed so as to reciprocate. A pump chamber 148 exists above the metering piston 21. In this pump chamber there is an outlet with a non-return valve ball 13 biased by a spring 14. In addition, a threaded joint 128 is provided that is directly connected to the check valve / SIP valve in the cylinder wall.

  In this embodiment, a configuration is shown that includes a motor 132 coupled to a worm mechanism drive 131 for adjusting the stroke. The worm mechanism drive 131 adjusts the stroke by changing the position on the setting pin or the set screw 66 via the worm mechanism wheel 130.

  In this embodiment, it is possible to adjust the stroke by changing the position of the stroke stop. This is different from the previous embodiment where a fixed origin is used and then the stroke is adjusted.

  In order to control the actual stroke length, a sensor / pickup unit 114 is mounted to detect the stroke, for example in the form of an encoder or potentiometer, to be continuous with the setting pin / set screw 66.

  Reference numeral 113 denotes a housing for a setting pin / set screw configuration.

  Reference numeral 124 denotes a piston packing that seals between the two spaces 149 and 147 where the leakage oil bypasses the hydraulic piston 6 on the drive oil side and the top lubricant side, respectively.

  Reference numeral 127 denotes an O-ring that seals between the base block 111 and the cylinder block 112.

  Reference numeral 133 denotes a fixing screw for fixing a bearing case for the worm mechanism wheel 130.

  Reference numeral 134 denotes an O-ring that seals between the bottom plate 110 and the base block 111.

7 Distributing plate; 21 Metering piston; 106 Hydraulic piston;
A chamber; B central bore; C insert cylinder;
D Internal bore; E Insert piston.

Claims (11)

  For example, in a marine engine, a hydraulic lubrication apparatus for a quantitative supply system for cylinder lubricating oil that has at least one hydraulic piston and is hydraulically driven to supply lubricating oil. The lubricating device is capable of receiving pressure from hydraulic oil, and has a plurality of metering supply pistons and a distributor plate for the purpose of operating the metering feed piston on the other side in contact with the metering feed piston. A hydraulic lubrication device having a distribution plate in contact with the at least one hydraulic piston for displacement, the hydraulic piston having an internal bore extending in a displacement direction of the hydraulic piston; and The inner bore includes an insert, and the insert has a hollow insert that is in contact with the hydraulic oil outlet. Insert cylinder for housing the piston is contained, hydraulic lubricating apparatus characterized by.   2. The hydraulic lubrication device according to claim 1, wherein the insert piston is screwed into a bore that passes when the hydraulic oil is supplied.   3. The hydraulic lubrication device according to claim 1, wherein the ratio of the cross-sectional area of the at least one hydraulic piston to the cross-sectional area of the metering piston is less than 7, preferably less than 5. 4.   The hydraulic lubrication device according to any one of the preceding claims, wherein the drain for the hydraulic oil is provided between an outside of the insert piston and the bore of the hydraulic piston.   The bore of the hydraulic piston, the insert cylinder, and the insert piston have a circular cross section and are arranged concentrically around a central axis. Hydraulic lubricator.   The metering system includes a supply line and a return line connected to the lubrication device via each of one or more valves for supplying hydraulic oil, each having a hydraulic piston, A central hydraulic oil supply pump connected via a supply line to a hydraulic cylinder capable of receiving the pressure of the fixed quantity supply cylinder, and a fixed quantity supply cylinder corresponding to the number of the plurality of cylinders in the engine The hydraulic lubrication device according to any one of the preceding claims, comprising a plurality of injection units connected to each of the first and second supply lines for cylinder lubricating oil.   For use in a hydraulic lubrication device for a metered supply system for cylinder lubricating oil, for example in a marine engine, which has at least one hydraulic piston and is hydraulically driven to supply lubricating oil In the hydraulic piston, the hydraulic lubrication device can receive pressure by hydraulic oil, and further, a plurality of fixed amount supply pistons, one side is in contact with the fixed amount supply piston, and the other side operates the fixed amount supply piston. And a distributor plate in contact with the at least one hydraulic piston for displacing the distributor plate for the purpose, wherein the hydraulic piston extends in the displacement direction of the hydraulic piston. And a hollow insert piston in which the bore is in contact with the outlet for the hydraulic fluid. Hydraulic piston, characterized in that it comprises an insert containing it are insert cylinder provided.   8. The hydraulic piston according to claim 7, wherein the insert piston is screwed into a bore through which the hydraulic oil is supplied.   9. A hydraulic piston according to claim 7 or 8, characterized in that the ratio of the cross-sectional area of the at least one hydraulic piston to the cross-sectional area of the metering piston is less than 7, preferably less than 5.   The hydraulic piston according to any one of claims 7 to 9, wherein the drain for the hydraulic oil is provided between an outer side of the insert piston and the bore of the hydraulic piston.   11. The bore of the hydraulic piston, the insert cylinder, and the insert piston have a circular cross section and are arranged concentrically around a central axis. The hydraulic piston according to one item.

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