Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16H—GEARING
  • F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
  • F16H61/38—Control of exclusively fluid gearing
  • F16H61/40—Control of exclusively fluid gearing hydrostatic
  • F16H61/4008—Control of circuit pressure
  • F16H61/4026—Control of low pressure
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16H—GEARING
  • F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
  • F16H61/38—Control of exclusively fluid gearing
  • F16H61/40—Control of exclusively fluid gearing hydrostatic
  • F16H61/4078—Fluid exchange between hydrostatic circuits and external sources or consumers
  • F16H61/4104—Flushing, e.g. by using flushing valves or by connection to exhaust
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B21/00—Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
  • F15B21/04—Special measures taken in connection with the properties of the fluid
  • F15B21/042—Controlling the temperature of the fluid
  • F15B21/0423—Cooling
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
  • F15B2211/205—Systems with pumps
  • F15B2211/2053—Type of pump
  • F15B2211/20546—Type of pump variable capacity
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/60—Circuit components or control therefor
  • F15B2211/61—Secondary circuits
  • F15B2211/611—Diverting circuits, e.g. for cooling or filtering
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/60—Circuit components or control therefor
  • F15B2211/61—Secondary circuits
  • F15B2211/613—Feeding circuits
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B7/00—Systems in which the movement produced is definitely related to the output of a volumetric pump; Telemotors
  • F15B7/005—With rotary or crank input
  • F15B7/006—Rotary pump input

Definitions

• the invention relates to a hydrostatic drive with a flushing device.
• Hydrostatic drives with closed circuits have the problem that heating of the pressure medium occurs during operation. Unlike in open circuits, the pressure medium required for operation is not sucked in here fresh from a pressure medium reservoir. It is therefore known in hydrostatic, closed circuits to provide a flushing device. This flushing device takes on the low pressure side of the hydrostatic closed circuit a certain amount of pressure medium, which is nachge Albertt by a feed device. The pressure medium supplied from the feed device is taken from a pressure medium reservoir and optionally cooled by means of an additional cooler. This makes it possible to reduce or, in the ideal case, to keep the temperature rise in the closed hydraulic circuit constant. Is in the closed circuit one from its neutral position out into two different
• the flushing device has a pressure control valve in addition to a flush valve. Upstream or downstream of the pressure holding valve, an additional valve device is arranged, which interrupts the connection between the purge valve and the tank volume when reversing the hydraulic pump.
• the hydrostatic drive has a hydraulic pump, which is connected in a closed hydraulic circuit with a hydraulic consumer.
• the hydraulic pump can be pivoted out of a neutral position, in which the pump is set to a zero delivery volume, in a first and a second direction. In the first and second directions, pressure medium is conveyed in opposite directions.
• the hydrostatic drive further comprises a flushing device which includes a
• Flush valve includes.
• the purge device has a pressure retention valve. While a withdrawal from the respective low-pressure line of the hydrostatic drive is effected via the flush valve, the pressure-maintaining valve is the
• the pressure-holding valve of a first opening pressure adjustable to a second, higher opening pressure By this adjustability between a first opening pressure and the higher second opening pressure, it is possible during the reversing a higher opening pressure of
• Pressure holding valve which is comparable in its operation with a pressure relief valve to adjust.
• the serial arrangement of the pressure holding valve and an additional shut-off valve, which is known from the prior art, can therefore be omitted. Only one valve is provided for raising the holding pressure in the hydrostatic circuit.
• the subclaims relate to advantageous developments of the hydrostatic drive according to the invention.
• a force of a spring acts in the closing direction of the pressure holding valve. This force acts on a closing body and determines the first opening pressure.
• the closing body is also for
• Closing body can be acted upon by means of an electromagnet with the additional closing force or, alternatively, this can be acted upon by a hydraulic force as an additional closing force.
• a bias of the closing body acting in the closing direction spring for setting the second, higher opening pressure and the first opening pressure is set.
• a spring bearing, on which a closing body is acted upon by a closing force acting spring, with respect to its relative position to the closing body is adjustable. The adjustment is again preferably either hydraulically or electromagnetically.
• a pilot valve is preferably provided.
• the higher, second opening pressure between the first opening pressure and a maximum opening pressure is adjustable.
• Such, preferably continuous adjustment of a pressure value for the second opening pressure makes it possible to respond to individual operating situations with only a small or, if necessary, a higher increase in the
• FIG. 1 shows a first embodiment of a hydrostatic drive according to the invention with a pilot-operated variable pressure holding valve and a hydraulic motor as a hydraulic consumer.
• FIG. 2 shows a second embodiment of the hydraulic drive according to the invention with a hydraulic cylinder as a hydraulic consumer and a change in the spring preload for adjusting the pressure-holding valve.
• 3 shows a third exemplary embodiment with an electromagnetically actuated pilot control of the adjustable pressure-holding valve
• 4 shows a first exemplary embodiment of a variable pressure holding valve
• Fig. 5 shows a second embodiment of a variable pressure holding valve.
• FIG. 1 The basic structure of a hydrostatic drive according to the invention is shown in FIG. 1.
• FIG. 2 and 3 which represent alternatives of the drive according to the invention, dispense with a repetitive representation of those components which are shown and explained in Fig. 1 and are applicable to the other drives in the same way.
• the hydrostatic drive 1 comprises a hydraulic pump 2.
• the hydraulic pump 2 is adjustable out of a neutral position with zero delivery volume in two opposite directions and thus promotes pressure medium to a hydraulic consumer, which is designed in the form of a hydraulic motor 3 in FIG.
• the hydraulic motor 3 is connected to the hydraulic pump 2 in a closed hydraulic circuit via a first working line 4 and a second working line 5. Depending on the set conveying direction promotes the hydraulic pump 2 in the first working line 4 or the second working line. 5
• a feed device 6 In order to replace leakage from the hydraulic circuit and a withdrawn amount of flushing oil, a feed device 6 is provided.
• the feed device 6 has a feed pump 7 coupled to the hydraulic pump 2.
• the feed pump 7 conveys pressure fluid from a tank volume 8 into the feed device 6.
• the feed device 6 also has a first suction and pressure limiting valve unit 9 and a second suction and pressure limiting valve unit 10.
• the Nachsaug- and pressure relief valve units 9, 10 each comprise a Nachsaugventil and a pressure relief valve arranged parallel thereto.
• the feed device 6 also has a feed pressure limiting valve 11, which is set, for example, to 25 bar and thus allows a maximum feed pressure of 25 bar.
• a flush valve 12 of a flushing device For removing pressure medium from the closed hydraulic circuit, a flush valve 12 of a flushing device is provided.
• the flushing valve 12 is connected to the first working line 4 and the second working line 5 and allows a withdrawal of pressure medium from the respective lower pressure leading first or second working line 4 or 5.
• the flushing valve 12 is connected to the first working line 4 and the second working line 5 and allows a withdrawal of pressure medium from the respective lower pressure leading first or second working line 4 or 5.
• Working line 4, 5 is in each case the low pressure leading working line 4, 5 connected to a first portion 13.1 of a flushing oil line 13.
• the flushing oil line 13 connects the flushing valve 12 with a pressure-holding valve 14.
• the pressure-maintaining valve 14 is connected to the tank volume 8 via a second section 13. 2 of the flushing oil line.
• the pressure-holding valve 14 is designed in the form of an adjustable pressure-limiting valve. It is acted upon in the closing direction by means of a spring 16, which exerts a force on a valve closing body. In the opposite direction, the pressure prevailing between the flushing valve 12 and the pressure-maintaining valve 14 in the first section 13.1 of the flushing oil line acts. By means of the force of the spring 16, a first opening pressure of the pressure holding valve 14 is set.
• a hydraulic actuator 17 is provided. This can be formed for example in the form of a pressurizable surface on the valve closing body. In this case, the force of the spring 16 and the hydraulic force act independently of each other in parallel on the valve closing body.
• a pilot valve 18 is provided to adjust the pressure acting there and thus the pressure retaining valve 14 in the closing direction acting force.
• the pilot valve 18 is acted upon in the direction of its rest position by means of a return spring 21. In this position, the hydraulic actuator 17 with the
• Tank volume 8 connected.
• a pressure medium source realized in the illustrated embodiment by a constant displacement pump 19 or by the feed pump 7, connected to the hydraulic actuator 17.
• the pilot valve 18 is brought into its second switching position by a further measuring surface of a further hydraulic actuator 20, the pilot valve 18 is acted upon against the force of the return spring 21 with an adjustable pressure.
• the there acting on the further hydraulic actuation pressure is supplied via a control line. This pressure is adjustable.
• the timing is preferred so that just before the passage of the hydraulic pump 2 by its neutral position, the further hydraulic actuator 20 is acted upon by a control pressure.
• the pressure on the hydraulic actuator 20 is released again and due to the force of the return spring 21, the pilot valve 18 goes back to its starting position shown in FIG.
• the hydraulic actuation of the pressure holding valve 14 was only temporarily subjected to a pressure.
• the hydraulic force acts on the closing body only temporarily and in addition to the force of the spring 16.
• the spring 16 z. B. is set to 16 bar, so a higher opening pressure at the pressure retaining valve 14 is temporarily set during reversing.
• the pressure drop in the closed hydraulic circuit is thus prevented because a removal of pressure medium via the flushing device is temporarily prevented.
• the asked by the feed device 6 is available
• Amount of pressure sufficient to equalize the leakage to maintain a minimum pressure in the system It is provided so much pressure medium that the pressure drop is completely prevented and it does not come to a shortage of the pump 2.
• a pressure relief valve 22 is connected.
• a largely constant pressure is set, so that the same pressure is always present for actuating the variable pressure holding valve 14.
• this arrangement is realized by the feed pump 7 with the feed pressure limiting valve 11.
• the second embodiment differs from the first embodiment of FIG. 1 essentially by the hydraulic consumer, which is realized in this case by a double-acting hydraulic cylinder 30.
• the distance between the valve closing body of the pressure holding valve 14 and the spring bearing ⁇ facing away ' can set a pressure and thus the bias of spring 16' by acting on the hydraulic actuator 17 can be adjusted.
• FIG. 3 another embodiment is shown.
• the pressure-maintaining valve in this case again corresponds to that already explained in FIG. 1.
• the hydraulic actuation is here connected via a designed as a pressure control valve 25 pilot valve with the constant pump 19.
• the pressure regulating valve 25 is biased in the direction of minimum outlet pressure via an adjusting spring 26.
• an electromagnet 27 In the opposite direction acts the force of an electromagnet 27, which can be controlled for example directly via a control unit.
• the control unit is supplied with a signal of an operating lever, so that a reversing operation, which is triggered by an operator, can be easily detected.
• Solenoid 27 with a signal the .Kraft of the spring 26 is partially compensated and a higher control pressure of the pressure control valve 25 is set. Parallel to the force of the spring 26 acts on the pressure control valve 25th this prevailing in the hydraulic actuator 17 higher control pressure.
• the pressure control valve 25 acts again as a pilot valve of the pressure-holding valve 14 or the hydraulic actuator 17 formed there.
• FIG. 4 shows a constructive embodiment of the pressure-holding valve 14 of FIG. 1.
• a valve-closing body 28 is arranged in the pressure-holding valve 14.
• a sealing surface is formed, which cooperates sealingly with a sealing edge 29 when the valve closing body 28 is pressed against the sealing edge.
• the sealing edge is formed on a valve seat body 31.
• the valve seat body 31 is arranged in a through hole of a first Genzousete'ils 32, that it cooperates sealingly therewith.
• an antechamber is formed in the valve seat body 31. This vestibule is in permanent connection with an inlet of the pressure-retaining valve 14 shown in FIG. 4 at the lower end.
• This inlet forms part of the first section 13.1 of the flushing oil line.
• discharge openings are provided in the valve seat body, which open into an annular groove of the first housing part 32.
• two holes are provided, via which the annular groove of the first housing part 32 with the Tank volume 8 is in communication and thus form part of the further portion of the Spülöltechnisch 13.2.
• the valve seat body 31 is held in sealing engagement with the first housing part 32 by a second housing part 33 is screwed into the through hole of the first housing part 32 and exerts an axial force on the valve seat body 31.
• a through hole is also formed.
• This is executed stepped and forms a spring chamber 34 together with the valve seat body 31.
• the spring 16 is arranged, which is supported on a formed on the side remote from the valve seat body 31 side of the spring chamber 34 radial step of the second housing part 33.
• a first spring bearing 39 is formed, which supports the spring 16 at the end opposite the stage. The spring 16 is thus clamped between a shoulder of the second housing part 33 and the first spring bearing 39 and acts on the valve closing body 28 in the closing direction.
• a projection 35 is formed, which in a guide portion 36 of
• the through hole of the second housing part 33 is sealingly guided.
• the through hole widens to the end remote from the sealing seat of the second housing part 33 to a control pressure chamber 37.
• the control pressure chamber 37 is connectable to a control pressure line, not shown.
• an end face 38 of the extension 35 can be acted upon by the control pressure.
• the extension 35 is designed in one piece with the valve closing body 28.
• it could also be provided a plunger instead of the extension 35, which acts on the valve-closing body 28 directly with a force acting in the closing direction force.
• the first spring bearing 39 is made adjustable. This can be done for example by using shims of different thickness.
• the operation of the adjustable pressure holding valve 14 is as follows: during the normal operation of the hydrostatic drive 1 of FIG. 1 is the
• Control pressure chamber 37 relaxed. In the closing direction of the pressure holding valve 14, therefore, only the force of the spring 16 acts. This defines a first opening pressure. Acts from the side of the first section 13.1 of the flushing oil line a hydraulic force on the
• FIG. 2 An embodiment of the pressure holding valve 14 'of Fig. 2 ' is shown in FIG.
• the spherical valve closing body 28 ' cooperates again with a sealing edge 29 of the valve seat body 31.
• the closing force on the spherical valve closing body 28 ' is generated by the spring 16 and transmitted through a first spring bearing 39'.
• the spring 16 ' is supported between the first spring bearing 39' and a second spring bearing 41.
• Both spring bearings 39 ', 41 are arranged in the spring chamber 34' which, as in the first embodiment, is formed by a first housing part 32 and a modified second housing part 33 '.
• a clamping piston 40 is longitudinally displaceably guided in the passage opening.
• the stopper head 41 is acted upon by a pressure in the control pressure chamber 37, wherein due to the differential surfaces, a force in the axial direction acts on the clamping piston 40, which acts in the closing direction of the pressure holding valve 14.
• Fig. 5 shows the initial position of the pressure holding valve 14 ', in which the first opening pressure is set.
• the stopper head 41 is in abutment with a stop screw 43 and the spring 16 'has a first bias.
• Stopping piece 42 is provided. By adjusting the height of the control pressure acting in the control pressure chamber 37, positions between the rest position shown in FIG. 5 and the first opening pressure can also be limited determines, and the maximum opening pressure when the stopper head 41 abuts against the stop piece 42 can be adjusted.
• the adjustment of the height of the control pressure takes place, for example, as a function of an adjustment speed of the hydraulic pump 2 during reversing.
• a damping piston 44 which is positioned movably in the axial direction, is also arranged in the antechamber.
• pressure-retaining valves 14 and 14 ' that a combination of the individual features of the pressure-retaining valves 14, 14' is possible with one another.
• a spherical valve closing body 28 ' can be used, on which the spring 16 is supported via a separately designed spring bearing.
• the first spring bearing 39 ' may also be formed in one piece with the valve closing body 28' of FIG. 5.
• the invention is particularly intended for drives in which frequent reversing occurs.
• a concrete pump may be mentioned.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Fluid-Pressure Circuits (AREA)
• Fluid-Driven Valves (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=42060579

Family Applications (1)

Country Status (3)

Families Citing this family (11)

Citations (3)

Family Cites Families (3)

• 2008
  • 2008-12-02 DE DE102008060066A patent/DE102008060066A1/de not_active Withdrawn
• 2009
  • 2009-11-27 WO PCT/EP2009/008456 patent/WO2010063414A1/de active Application Filing
  • 2009-11-27 CN CN200980148223.XA patent/CN102232148B/zh not_active Expired - Fee Related

Patent Citations (3)

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