Classifications

• • 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
  • F15B21/008—Reduction of noise or vibration
• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02F—DREDGING; SOIL-SHIFTING
  • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
  • E02F9/20—Drives; Control devices
  • E02F9/22—Hydraulic or pneumatic drives
  • E02F9/2203—Arrangements for controlling the attitude of actuators, e.g. speed, floating function
  • E02F9/2207—Arrangements for controlling the attitude of actuators, e.g. speed, floating function for reducing or compensating oscillations
• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02F—DREDGING; SOIL-SHIFTING
  • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
  • E02F9/20—Drives; Control devices
  • E02F9/22—Hydraulic or pneumatic drives
  • E02F9/2203—Arrangements for controlling the attitude of actuators, e.g. speed, floating function
  • E02F9/2214—Arrangements for controlling the attitude of actuators, e.g. speed, floating function for reducing the shock generated at the stroke end

Definitions

• Hydraulic control arrangement The invention relates to a hydraulic control arrangement for controlling a work tool of a mobile implement according to the preamble of claim 1.
• Such control arrangements are used, for example, in excavators, backhoe loaders to actuate a boom and a shovel articulated thereon.
• These work tools are operated by means of hydraulic cylinders, the pressure chambers of which can be connected to a variable displacement pump or a tank via a control block.
• a problem with such work machines is that at the end of a movement of the work tool, its comparatively large mass has to be braked.
• vibrations occur at the end of the pivoting movement, which make it difficult for the driver to bring the bucket into the desired position.
• These vibrations are caused by the kinetic energy to be dissipated during the braking process, by means of which the hydraulic cylinders of the working device are subjected to a force which acts counter to the direction in which the hydraulic cylinders were subjected to the swiveling movement.
• a vibration damping module is proposed in US Pat. No. 6,474,064 B1, in which the vibration damping module Tool build-up pressure in a drain line between the hydraulic cylinder and the control block can be reduced to a low pressure side via a valve arrangement, in the present case to a feed line between the control block and the hydraulic cylinder. This reduces the pressure difference in the flow and in the discharge, so that the vibrations mentioned at the beginning are damped.
• 6,474,064 Bl has a damping valve connecting the flow and the drain line, which is biased in the closing direction by a spring and whose oppositely effective control chambers can be acted upon with a pressure difference which corresponds to the pressure drop in the flow line or . correspond to the check valve arranged in the drain line.
• this damping valve is acted upon by the pressure difference across the check valve of the flow into its closed position.
• the damping valve is brought into an opening position via the pressure drop occurring in the pressure medium outlet via the check valve arranged therein, in which the pressure medium supply and the pressure medium return are connected to one another - the vibrations are damped and very quickly dismantled.
• a disadvantage of this known solution is that a considerable outlay in terms of device technology is required, since two check valves and the damping valve associated with the two lines are provided both in the flow line and in the return line and via one complex ductwork must be connected.
• the invention is based on the object of creating a hydraulic control arrangement for controlling a work tool of a mobile work device, with which the generation of vibrations when braking the work device can be avoided with minimal effort or at least limited to an acceptable level.
• the hydraulic control arrangement has a vibration damping device for damping the aforementioned vibrations, with two pilot-operated check valves arranged in opposite directions, which are arranged in a connecting line between the pressure medium inlet and outlet.
• the check valves are each acted upon in the opening direction by the pressure in the outlet or in the flow and in the closing direction by this pressure and with the force of a spring.
• the device according to the invention with two pilot operated shut-off valves is extremely simple and can be constructed therefore easier and cheaper to manufacture than the constructions described above.
• a damping nozzle can be provided in the connection line between the two shut-off valves.
• the hydraulic control arrangement according to the invention is of particularly compact construction if the two shut-off valves are integrated in the control slide, so that existing systems can be retrofitted by replacing the control slide.
• control slide has an axial bore which forms the connecting line and into which the two check valves are inserted.
• this axial bore is expanded on both sides to form spring spaces for a spring of the respective check valve via a radial shoulder, which forms a valve seat for a valve body of the check valve.
• the valve body of the shut-off valve is advantageously designed with a surface difference, the outlet surface acting in the opening direction being able to be subjected to the discharge pressure.
• the channel guide is particularly simple if the spring chamber of the check valve can be connected to the tank connection or a low-pressure side after a predetermined stroke, so that the spring chamber is relieved of pressure after this stroke and the forces acting in the closing direction on the closing body are reduced accordingly ,
• the valve body is designed as a hollow piston and has a transverse nozzle bore in a radially recessed area of its piston jacket, which interacts with a bore star of the control slide in order to apply the pressure in the outlet to the spring chamber.
• the stroke of the valve body of the check valve can be limited by a stop sleeve inserted into the control slide.
• a nozzle is formed in the casing of the control slide, via which the pressure in the outlet can be applied to the spring chamber of the outlet-side shut-off valve.
• This nozzle is closed after an initial stroke of the control slide.
• the shut-off valve on the outlet side is held closed by the pressure acting in the outlet, although its spring chamber is connected to the tank chamber via the jacket opening, so that the connecting line according to the invention cannot be opened with a small stroke of the control slide.
• This nozzle is arranged parallel to the nozzle bore and can be controlled by the valve body of the check valve.
• the closing movement of the valve bodies of the check valves is damped in that the play between the valve body and a guide is made relatively narrow.
• FIG. 1 is a circuit diagram of a control arrangement according to the invention
• FIG. 2 shows a section through a proportional valve for a control arrangement according to FIG. 1
• 3 shows a detailed illustration of the proportional valve from FIG. 2
• FIG. 4 shows a detailed illustration of a directional valve of a further exemplary embodiment of a control arrangement according to the invention.
• Figure 1 shows a circuit diagram of a control arrangement
• swivel cylinders 2, 4 of a mobile working device for example an excavator loader
• boom 8 of which carries a shovel 6 in the horizontal direction ie. H. to pivot parallel to the floor (drawing plane in Figure 1).
• pivot cylinders 2, 4 are supported on the frame of the backhoe loader lying side by side in the horizontal direction and act on the boom 8 via a link arrangement 10.
• the control block consists of a number of valve disks, of which one valve disk 14 is assigned to the two swivel cylinders 2, 4, while the others
• Valve discs of other consumers of the backhoe loader For example, the swivel cylinder for the bucket, the swivel cylinder for swiveling the boom in the vertical direction, the slewing gear drive, etc. are assigned.
• the basic structure of such a control block is described in the RD information sheet of the applicant with the number RD 64 127, so that only the elements essential to the invention need to be discussed here.
• the valve disk 14 which forms the control arrangement according to the invention essentially consists of an LS directional valve arrangement 16 with a proportionally adjustable directional valve, via which the pressure medium flow direction and the pressure medium speed can be set.
• This directional valve forms a metering orifice with which a pressure compensator of the LS directional valve arrangement is assigned.
• LS systems with downstream pressure compensators it is achieved that with a sufficient quantity of pressure medium supplied, there is a certain pressure difference across the metering orif regardless of the load pressures of the hydraulic consumers, so that the pressure medium speed is independent of the individual load pressure of the consumer.
• the highest load pressure of the consumers controlled via the control block is tapped via an LS line 13 with changeover valves and fed to a pump regulator of the variable displacement pump 12, so that this delivers a pump pressure which, with sufficient supply to all consumers, is above the highest by a predetermined pressure difference Load pressure is.
• LS systems reference is made to DE 199 04 616 AI.
• the valve disk 14 has a pressure medium inlet P and a pressure medium return S as well as two working connections A, B which are connected to the swivel cylinders 2, 4.
• the working connections A, B are each connected to annular spaces 18, 20 of the swivel cylinders 2, 4, which in turn are connected by diagonal lines with the cylinder chamber 22, 24 of the other pivot cylinder 2, 4 are connected.
• the two working connections A, B of the valve disk 14 are connected to the swivel cylinders 2, 4 via a flow 26 or a flow 28.
• the valve disk 14 is designed with a vibration damping device 30, which is indicated in FIG. 1 by a double-dotted line.
• This vibration damping device 30 has two oppositely arranged, pilot-operated check valves 32, 34, which are arranged in a connecting line 36 connecting the flow 26 to the outlet 28.
• a damping nozzle 38 for damping high-frequency pressure fluctuations is formed between the two check valves 32, 34.
• the check valves 32, 34 are each pressurized in the opening direction via an unlocking channel 40, 42 and in the closing direction via a channel 44, 46 with the pressure in the feed 26 and in the drain 28.
• a control chamber of the check valves 32, 34 which is effective in the closing direction can each be connected to the tank T via a relief device 48, 50.
• This relief device 48, 50 controls the connection to the tank T only after a predetermined initial stroke of a control slide of the LS directional control valve arrangement 16.
• FIG. 2 A concrete embodiment of the vibration damping device 30 is now explained in FIG. 2, in which the latter is integrated in the control slide 52.
• the valve disk 14 shown in partial view has a valve bore 54 in which the control slide 52 is guided so as to be axially displaceable.
• On the outer circumference of the spool are a flow control groove 56, two connecting tion control grooves 58, 60 and a sequence control groove 62 are formed.
• the valve bore 54 is in the radial direction to a tank chamber 64, a flow chamber 66, a connection chamber 68 arranged downstream of the LS pressure compensator, not shown, a pressure compensator chamber 70 arranged upstream of the LS pressure compensator, an inlet chamber 72, a further connection chamber 74 arranged downstream of the pressure compensator Drain room 76 and another tank room 78 expanded.
• Control edges 80, 82 with fine control notches are formed on the adjacent ring end faces of the connection control groove 58 and the connection control groove 60, via which a connection from the inlet space 72 to is made when the control slide 52 is displaced axially to the left or right in FIG Pressure compensator chamber 70 is controllable.
• connection from the discharge space 76 to the tank space 78 or to the connection space 74 can be opened via two control edges 84, 86 formed by the discharge control groove 62.
• the two control edges 88, 90 formed by the flow control groove 56 control the connection from the flow space 66 to the tank space 64 or from the connection space 68 to the flow space 66 when the control slide 52 is axially displaced. All mentioned control edges are designed with fine control notches (see also the RD leaflet mentioned).
• the control slide 52 has an axial bore, via which the connecting line 46 is formed according to FIG. 1.
• the connecting line 46 In this connecting line 46, the check valve 32 assigned to the flow and the check valve 34 assigned to the return are arranged.
• a nozzle body In the flow area between the shut-off valves 32, 34, a nozzle body is inserted into the connecting line 46, which forms the damping nozzle 38.
• the two pilot-operated check valves 32, 34 have an identical structure, which is explained below with reference to FIG. 3, which shows the check valve 32 in an enlarged view.
• the connecting line 46 is widened step-wise toward its two end sections, so that a valve seat 94 and a spring chamber 96 adjoining it are formed.
• a valve body 98 designed as a hollow piston is prestressed against the valve seat 94 by means of a spring 100, which in turn is supported on a support sleeve 102 which is inserted into the spring chamber 96 and is fixed in position in the axial direction by the locking screw 92.
• valve body 98 is stepped back towards the valve seat 94, its maximum outside diameter corresponding to the diameter of the spring chamber 96, the valve body 98 being stepped back towards the valve seat 94.
• the radially recessed part 102 of the valve body 98 forms, with the inner circumferential wall of the control slide 52, an annular pilot control chamber 104, which is connected to the flow chamber 66 via a bore star 106 of the control slide 52.
• annular pilot control chamber 104 which is connected to the flow chamber 66 via a bore star 106 of the control slide 52.
• Valve body 98 has a nozzle bore 108 which opens into the interior of valve body 98, so that pilot chamber 104 is connected to spring chamber 96 through this nozzle bore 108.
• the jacket of the control slide 52 is provided with jacket openings 110 which, in the basic position of the control slide 52 shown, are covered by an annular web 112 between the flow chamber 66 and the tank chamber 64. With an axial displacement of the control slide 52 from this neutral position to the left, these openings 110 are opened, so that a connection between the spring chamber 96 and the tank chamber 64 is opened and the valve body 98 is relieved in the opening direction.
• the opening cross section of the nozzle bore 108 is substantially smaller than that of the open jacket openings 110, so that the pressure medium volume flow flowing out to the tank T is greater than the pressure medium volume flow flowing through the nozzle bore 108.
• the stop sleeve 101 is designed such that the rear of the valve body 98 cannot control the manhole openings 110. As already mentioned, the construction of the pilot-operated shut-off valve 34 is identical, so that explanations in this regard are unnecessary.
• the boom 8 is pivoted, for example the annular space 18 of the pivot cylinder 2 and the cylinder space 24 of the pivot cylinder 4 being supplied with pressure medium and the two other pressure spaces 20, 22 being connected to the tank T, so that the boom 8 is pivoted to the left in the illustration according to FIG. 1.
• the control slide 52 is acted upon by a pilot control device with a control pressure difference, so that it is shifted from the neutral position shown to the right (FIG. 2).
• the connection from the inlet space 72 to the pressure balance space 70 is opened via the control edge 80, and the pressure medium flows through the
• the control edge 88 opens its connection to the flow space 66, so that the pressure medium can flow via the flow space 66 and the working port A to the pressure spaces 18, 24 of the swivel cylinders 2, 4.
• the pressure compensator adjusts itself to a control position in which the pressure drop across the metering orifice (controlled cross-section between the inlet chamber 72 and the pressure compensator chamber 70) is kept constant regardless of the load pressure.
• the axial displacement of the control slide 52 to the right also opens the connection from the discharge space 76 to the tank space 78, so that the pressure medium can flow out of the pressure spaces 22, 20 of the swivel cylinders 2, 4 to the tank T.
• the boom 8 is accelerated accordingly to the left and then moves with a constant Speed. Since the control slide 52 is shifted to the right from its position shown in FIG. 2, the jacket openings 110 assigned to the check valve 32 are blocked by the annular web 112, so that the valve body 98 of the check valve 32 is acted upon in the closing direction by the pressure on the supply side, the spring chamber 96 thereof (see FIG. 3) is connected to the flow space 66 via the bore star 106 and the nozzle bore 108.
• the jacket opening 110 of the control slide 52 assigned to the outlet-side shutoff valve 34 is opened towards the tank chamber 78, so that the rear of the valve body 98 of the shutoff valve 34 is relieved.
• the valve body 98 of the check valve 34 can be lifted off its valve seat 94 by the pressure acting on its annular end face in the outlet space 76 even at a constant speed of the boom 8, so that the outlet pressure is also present in the connecting line 36 and the valve body 98 of the check valve 32 in the opening direction.
• this remains in its closed position at constant boom speed, since the significantly higher inlet pressure acts on the rear.
• the pilot control device is reset and the boom 8 is braked accordingly quickly.
• the boom tries to move further due to its inertia, so that the pressure in the pressure chambers 22, 20 of the swivel cylinders 2, 4 increases - as described at the beginning. This leads to an increase in the pressure in the outlet 28.
• This pressure is also present in the pilot control chamber 104 at the right end section of the control spool 52 (see FIG. 2), so that the annular end face of the pilot valve 98 resulting from the area difference of the pilot piston 98 Check valve 34 is acted upon by this increased discharge pressure.
• the back of the outlet-side shutoff valve 34 is pressurized in the outlet space 76, so that its valve body is biased into the closed position.
• the spring chamber 96 of the check valve 34 is relieved via the jacket openings 110 at the right end section of the control slide 52 to the tank chamber 78, so that the valve body 98 of the check valve 34 through the on it Ring end face acting increased pressure in the drain space 76 can be opened against the force of the spring 100, and the connecting line 46 is opened.
• the valve body 98 of the shut-off valve 32 (FIG.
• the connection of the jacket openings 110 to the tank space 78 is also controlled accordingly, so that the valve body 98 of the outlet-side shutoff valve 34 is again subjected to the outlet pressure in the closing direction.
• the valve body 98 of the blocking valve 32 would also be returned in its closing direction - the damping according to the invention could not be achieved with the required effectiveness.
• the closing bodies 98 are guided in the control slide 52 with a relatively close fit, so that a damping effect is achieved solely by this fit and the spring chamber (96) is sealed. Additional damping takes place via the damping nozzle 38 in the connecting line 36.
• the damping of the valve body closing movement of the check valves 32, 34 is selected such that the closing movement is delayed until the vibrations mentioned are reduced when the boom 8 is braked.
• the control arrangement according to FIG. 4 can be modified.
• two nozzles 114, 116 are provided in the casing of the control slide 52, via which the spring spaces 96 of the check valves 32, 34 are each connected directly to the flow space 66 and the drain space 76.
• the nozzle 116 connects the spring chamber 96 of the shut-off valve 34 to the outlet space 76 in addition to the nozzle bore 108, so that the shut-off valve 34 on the outlet side is kept closed due to the larger effective connection cross-section, although the jacket openings 110 open the connection to the tank to have.
• This outlet-side nozzle 116 is at an axial displacement of the control slide 52 after a certain stroke s ( Figure 4), which is larger than the one described above Stroke h controlled so that the check valve 34 corresponds to the above-described embodiment in terms of function during the following stroke.
• the rear end face of the valve body 98 is in each case provided with a chamfer 118, so that the mouth region of the nozzles 114, 116 is not covered in the closed position of the valve body 98.
• the nozzles 114, 116 have no or negligible effect in the case of large deflections of the control slide (stroke> s), since these are controlled when the control slide 52 is deflected and the chamfered valve bodies 98 of the check valves 32, 34 during the damped closing movement described above Back of the valve body 98 are controlled as long as they are lifted off the valve seat 94. Only when the vibrations are reduced and when the valve bodies 98 are placed on their valve seat 94 are these nozzles 114, 116 opened again.
• the variant shown in FIG. 4 can be used, for example, to prevent the control slide 52 from being adjusted quickly and at short intervals and the backhoe loader with its boom 8 dropping down the slope, even though the control slide 52 was actuated in such a way that a boom movement directed uphill is carried out should.
• the effect of the damping device according to the invention is overridden by the additional nozzles 114, 116 when the control spool 52 is moved slightly and the vibrations described at the outset are accepted.
• the two relief devices 48, 56 (according to FIG. 1) are described in FIGS. 2, 3 and 4.
• NEN embodiments formed by the jacket openings 110 of the spool 52, via which the connections of the spring chamber 96 to the tank chamber 64 can be controlled and which are controlled at short strokes h of the spool 52 from its neutral position.
• the unlocking channels 40, 42 indicated in FIG. 1 are formed in the specific exemplary embodiments by the bore stars 106 and the pilot control chambers 104, via the annular end faces of the valve bodies 98 of the shutoff valves 32, 34, which are effective in the opening direction, with the pressure in the feed 26 or in the drain 28 are applied.
• the vibration damping device has two pilot-operated check valves arranged in opposite directions, which are arranged in a connecting line between a pressure medium inlet and a pressure medium outlet.
• the check valves are acted upon in the opening direction by the pressure in the outlet or in the flow and in the closing direction also by this pressure and the force of a spring.
• Connection control groove 60 Connection control groove 62 Drainage control groove 64 Tank compartment Flow space connecting space Pressure compensator space Inlet space connecting space Drainage space Tank space Control edge Control edge Control edge Control edge Control edge Locking screws Valve seat Spring space Valve body Spring Stop sleeve Reset valve body Pre-control space Bore star Nozzle bore Sheath breakthrough Ring web Nozzle Nozzle Chamfer

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mining & Mineral Resources (AREA)
• Civil Engineering (AREA)
• Structural Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Analytical Chemistry (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Mechanical Engineering (AREA)
• Fluid-Pressure Circuits (AREA)
• Operation Control Of Excavators (AREA)

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• 2003
  • 2003-11-27 DE DE10355329A patent/DE10355329A1/de not_active Withdrawn
• 2004
  • 2004-11-19 US US10/580,715 patent/US7454906B2/en not_active Expired - Fee Related
  • 2004-11-19 AT AT04802777T patent/ATE369465T1/de not_active IP Right Cessation
  • 2004-11-19 JP JP2006540157A patent/JP4682148B2/ja not_active Expired - Fee Related
  • 2004-11-19 DE DE502004004602T patent/DE502004004602D1/de active Active
  • 2004-11-19 WO PCT/DE2004/002565 patent/WO2005052268A1/fr active IP Right Grant
  • 2004-11-19 EP EP04802777A patent/EP1711662B1/fr not_active Not-in-force

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