DE2510667A1 - HYDRAULIC CONTROL AND REGULATING UNIT, IN PARTICULAR FOR INJECTION MOLDING MACHINES - Google Patents

Description

ΥΞΒ Plast and Elast processing machine Eombinat Karl Marx City

Hydraulic control and regulating device, especially for injection molding chinen

The Irfindung concerns a hydraulic control and regulating device for controlling and regulating oil flows and / or hydraulic ones Press »especially for hydraulic circuits of injection molding machines, the path, servo, pressure difference, Pressure switching, pressure limiting, pressure reducing, two-way .and Has three-way flow dividing and / or flow dividing functions

Directional control valves are usually used to control an oil flow and pilot-operated check valves used «Directional control valves usually have a slide valve in a housing Piston valve with grooves, which, depending on the position, has different connections between the bores in the housing and thus directs an oil flow into a preselected pipe system or other element The channels are sealed against each other by the precise fit of the piston in the housing, releasable check valves usually have one or more seat elements, which in one direction through the behind the element in the direction of the seat acting pressure, which is often reinforced by a spring, are pressed onto the seat, and thus the flow of oil in it Block direction »By a pressure increase on the opening side of such a valve above the pressure on the closing side and the effect of a possibly locking spring, it opens Valve independently · By mechanical or hydraulic The piston can lift the seat element (valve ball) from the seat and thus cancel the non-return effect of the valve will·

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In contrast to piston slide valves 1, seat valves work without current ο

Usually stream are part valves for controlling a hydraulic delivery flow valves with the proportional character and servo valves used "current control valves operate on the base ₁ that a differential pressure valve, the pressure difference to work via a choke constant adjusts · way valve with proportional character as normal way valves, said piston valve a throttle bevel or notch contains and is regulated depending on the position

Servo valves are usually designed as piston slide valves with square control or rotary slide valves The flow control becomes more defined by the start-up Throttle gaps between the edges of the throttle slide and the edges of the housing possible · Such servo valves can also with pressure feedback can be used for pressure control »There is also a comparison piston on the piston valve · To regulate the pressure, pressure limiting and pressure reducing valves are usually used, both with piston spools as well as can be equipped with seat elements as a regulating element »

A spring is used as a reference element for direct-operated pressure valves and in the case of pilot-operated valves generally a spring with a low spring rate and an oil pressure determined by a pilot control system are used Pressure relief valves acts on the seat element in the closing direction, the spring force and the comparison pressure and in the opening direction of the system pressure · With pressure reducing valves, the directions are reversed »Pressure reducing valves are either due to the pressure build-up upstream of the valve until the pilot valve responds, or are opened, as far as the pilot oil flow is provided on the secondary side until it responds of the pilot valve open »

Directional control valves have the task of oil flows in preselected directions to lead »Several connections can be made at the same time are »Except for proportional directional control valves, directional control valves have no current control functions.

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Via directional control valves, there is always a leakage flow determined by the size of the clearance between the housing and the piston and the distance between the oil feeds. Non-return valves have the function _f to the oil flow in one direction to lock and to the extent it is pilot operated check valves is run-way valve functions in the reverse direction at certain preselected times · When check valves usually no leakage current occurs across the seating elements on ·

Servo valves are used to regulate the flow or pressure and have a piston valve, which is due to the low or none Overlap to the housing has very little play, that is to say that a valve must have a high level of manufacturing accuracy Control edges must be exactly sharp-edged · Signs of wear and tear on the control edges have a strong impact the control accuracy and the leakage current · The leakage current that occurs has an effect when operating as a pressure servo valve (Puncture of a pressure reducing and pressure limiting valve es) particularly disadvantageous, as the valve must constantly divert this leakage current into the drain »

Due to the high manufacturing accuracy, it is with the servo valve required, also corresponding for the main control circuit Use fineness of pilter for filtering the main oil flow Pressure reducing valves generally have the disadvantage that they only reduce pressure peaks very slowly · In many cases of pressure regulation in injection molding machines z · B · when switching from injection pressure to holding pressure is, however a quick reduction of the pressure to a set value is required

Usually this is bad behavior of the pressure reducing valves countered by the secondary circuit being tapped through a main control part of a pilot operated pressure relief valve which is controlled by the same pilot valve as the pressure reducing valve, which is the case with Spritzgießmas chJuaen Significant additional economic expenditure means »The preceding analysis shows that the existing Solutions essentially only represent a function for a specific purpose and, moreover, often not a satisfactory solution.

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genes for various purposes, especially with rapidly changing processes such as those occurring in injection molding machines, represent ©

The purpose of the invention is to provide one or more control and / or regulating functions with a hydraulic control and regulating device to perform and thereby reduce the aforementioned disadvantages, and thus the hydraulic circuit, especially of Injection molding machines, much simpler and more reliable at the same time to design·

The invention has for its object to provide a device which respectively ^"1 control system in a hydraulic drive, in particular by injection molding controls the flow and / or regulates and / or controls the pressure, filling at the same time or in sequence several functions

According to the invention, the object is achieved by a hydraulic control and regulating device, which consists of a housing in in which there are one or more pistons that interrupt the connections between ^ e two cavities in the housing in which the Piston forms a sealing edge together with a conical bevel in the housing and through the same on both circular surfaces Pressure is loaded, the piston mechanically preferably by a spring or hydraulically due to the pressure effect on a small difference area, whereby the area facing away from the sealing edge is larger, is pressed onto the seat and in which is a control and regulating device that this piston (seat element) mechanically pushes open, stops or relieves pressure again.

If this mechanical actuation of the control device changes its position, one or more seat elements also change its position Location"

As a rule, there is no positive connection between the seat elements and the control device, but only in beta direction of movement © a force-fit connection * The control device consists preferably of the mechanical actuation device for the seat elements (a piston rod or a

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Lever) and an ove system, which from one or both sides, whereby one side can represent a differential surface, is acted upon with one or more pilot pressures · By a suitable combination of such seat elements with a corresponding actuation system and a dedicated control of the actuation system, hydraulic ones are created Control and regulating devices for the following punctures: path, servo, pressure differential, pressure switch, pressure reducer, Two-way or three-way flow control and flow dividing function B. a servo valve with square control function of two seating element groups, each consisting of two seat elements connected to one another and which are optionally controlled by the control device pushed open or held up for a corresponding amount. The invention can also be based on this lying working and construction principle a pressure reducing valve can be created which includes the pressure limiting function and by means of appropriate pilot control also the pressure connection to a secondary circuit and the pressure relief of the Secondary circuit can take over «With such a device in injection molding machines s # B · the entire control of the Injection movement, injection pressure limitation, holding pressure, the back pressure and the back pressure release can be realized If the Koib system is not controlled by hydraulic pressure, but by an adjustable leather, a direct control is created es pressure reducing valve with secondary pressure limitation

May further by ITutaung the ^j inventive solution for AEIE control of the pressure difference across the throttle, a flow control valve in two-way and three-way version and current portion can be realized valve · In this case, by varying the pressure difference across the throttle of the flow rate at a constant throttle setting in stages OR can be continuously changed, which can be used inexpensively in injection molding machines with constant displacement pumps or memory for controlling the injection speed *

For this purpose, an additional Eoibensystem can be used expectant, _f s by the pressing force of the seat element, it is changed to the Sits · separate by two centrally arranged piston having on

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the piston rods acting on the s it ζ elements becomes the flow dividing function reached | where the part ratio is through, the piston- diameter ratios is determined »A variation or scheme of the flow eil ratio is through an additional in Piston system acting in the closing direction of a seat element is possible.

By series connection of two pistons _t sitting on a common piston rod or umsteuerung- on a common lever acting in a valve and the optional connection of a pilot system, it is possible with this valve, both the S tr and realize regulation and the pressure regulation. If the mechanical actuation system is replaced by a magnet, a directly controlled directional valve is created.

It is possible in additional construction variants of the simultaneous Actuation of several seat elements in the pressure reducing valve when switching on and / or additional connections when limiting the pressure produce and dependent or e.g. a pressure build-up to control the following hydraulic processes * So · in injection molding machines after the mold clamping force has been built up by the additional connection the nozzle approach movement is initiatedH | or when used on the injection side during injection compression molding, the embossing movement can be triggered.

By here- explained 4-2a? F charge underlying labor laws = and design principle it is possible to virtually free of leakage current © hydraulic control uad control devices to be created en di _g © based on the modular system? can be, being through exchanges. fewer components, the functions Yieier bekanater · hydraulic valve © be realized _f wherein from one device simultaneously or in the sequence number of different & Itmir are met and the _ion-f are one © Tabar particular in SpritzgießmascMjLss.

For the application of the principle an- Se ^ Yoves / feii ^ ::: sr. "Le or pressure control, the mz £ Q & ä & 3l ± & k & ^ G ^ v-icei ^ sg

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and required filter fineness far below the value for conventional ones Servovalves. "

The creation of control and regulating devices with small, medium and large dimensions is based on uniform device designs possible, which enables the creation of similar circuit diagrams for the entire series of injection molding machines «

In the following, the invention will be based on a few general examples explained.

In the accompanying drawings show:

Pig x 1; the servo valve for flow control in a sectional view

Fig. 2: the servo valve for pressure control in sectional view

Fig. 3 * aas pressure reducing valve with pressure limitation on the secondary side «

In Fig. 1 a servo valve for flow control is shown.

In a housing 61, there are two seat element combinations consisting of ge two seat elements 1 and 2 or "3 and 4 * Furthermore, located between the seat elements 1,2 or _o 3, for forming a piston system 5, the housing parts 62, 63 and 64 the cylinder . The piston 5 sits on the piston rod 7 and 8, which in the pressure-equalized state of the piston 5 lies on the piston sides 27 and 28. The same pressure is applied to the seat elements 1 and 3 10, 11, 12 and 13 are hydraulically connected to each other via the line system 44, 45 »46 * The lines 44, 45, 46 are so large that the same pressure prevails on the seat element sides 23, 24, 25 and 26.

In order to achieve damping effects, the lines 45 and 46 a throttle can be installed. It is also possible for various purposes such. B * as a pilot operated directional valve to separate the line 44 and only to achieve the same pressures in trees 10 and 12 or 11 and 13.

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If there is pressure in room 10 and thus also in rooms 11, 12, 13, then there is el ementf laughing 23t 24 or 25 and 26, which are equal in area, are the same Pressure on and the seat element combinations 1, 2 or 3i 4 turn through the pressure of the leather 35 or »36 on the seats 31 and 33 or 32 and 34 pressed and thus a connection of the rooms 10 and 15, 11 and 16, 17 and 19 * 18 and 20 prevented · In particular In the case of hydraulic centering, the springs 35 and 36 do not need to be grounded, but the surfaces 23 and 26 must be larger than the areas 24 and 25. The piston 5 is used to carry out certain control tasks by pressure differences in the spaces 21 and 22 and their effect on the surfaces 28 and 27 in cooperation with the springs 35 or 36 position-controlled, i.e. is zB, via a nozzle-baffle system 47 a higher pressure is set in the line 43 than in the line 42 and thus the pressure on the surface 27 larger than on the surface 28, the piston 5 moves and the piston rod 8 pushes the seat element combination 1, 2 so far until the balance of forces resulting from the action of the Differential pressure on the piston surface 27 resulting force and the force of the spring 12 and which is also derived from the oil flow from the space 10 into the space 15 and from the space 17 into the space resulting axial force happens «. If the line 38 is now connected to a Side of a hydraulic motor that can be reversed in the direction of rotation and the line 39 is placed on the other side and the line 40 is placed on the drain, in this way both the speed of the motor can be determined via the opening width of the between the housing 61 and the seat elements 1 and 2 or 3 and 4 resulting throttle points and the direction of rotation via the preselection of the side with the higher pressure, space 21 or 22, can be changed · The oil supply to the pilot control system 47 takes place via the line 41 from a separate oil circuit or from the pressure line 37 instead of the nozzle-baffle system shown Is it possible to use other servo pilot control systems? Directional control valves, pressure relief valves, throttle circuits, etc. to be used

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It is also possible to use this system as a directional valve to replace the piston system 5, 7, 8 with one or two magnets Valve performs pressure control tasks »Should only one valve side perform pressure control tasks, e. B ₀ perceive pressure reducing, pressure limiting or pressure switching functions, a seat element side 23 or 24 or 25 or 26 must have a larger diameter Let the piston system act on the seat element surfaces 23 or 26 «If a valve is to have either a pressure regulating or a flow control function, a second piston is to be arranged on the piston rod 7 or 8, which is either pressurized by the pressure in space 10 or 11 or is depressurized.

The number of seat elements connected in series can can be varied as required

3? Ig · 2, a pressure he vo valve is shown · in a casing 61 *, there are two seat elements 1 * and 3 ¹ that the trees 15 * and 10 * and 10 'and 16' over the sealing edge 31 'or Separate 32 'from each other

The seat elements 1 ¹ and 3 ¹ contain bores 45 * and 46 *, which connect the spaces 12 * and 10 * or · 10 * and 13 * with one another, that is, they are pressure-balanced · by the springs 35 * and 36 * the seat elements 1 * and 3 * are pressed onto the seat of the housing 61 'and with it form the sealing edge 31 * and 32 * · A transmission pin 2 * and 4 * is located on the seat elements 1 * and 3 *.

Furthermore, a piston system is located in the housing 61 *, consisting of the pistons 5 'and 6', which are connected to the lever 9 * ^{via the connecting rods 7 1} and 8 * in the hinge points 48 *, 49 *, 50 * and 51 ^f are·

The piston surfaces 27 * and 28 'are not equal to the piston surfaces 29 * and 30 *, where expediently the surfaces 27 ' and 28 'are the larger · Due to this area difference is the Pressure comparison possible

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If the line 37 * is considered as a pressure supply line (primary side) to a hydraulic circuit, the line 38 * as a cylinder line (secondary side) and the line 40 * as a discharge line, if the equilibrium position of the piston-lever system is disturbed, then the Flapper system 47 ^{f increases} the pressure in line 42 * and thus in space 21 * and thus reduces the pressure in space 22 * and thereby reduces piston 5 ^f through the force that is the product of the pressure in space 21 * and the area 27 * results against the force that results from the pressure in space 10 · and the area difference between areas 28 * and 30 * and the force that results as the product of the pressure in space 22 ^f and area 29 * and the spring force the spring 35 ^{f is} displaced and thus the seat element 1 is opened via the connecting rod 8 * and the transmission ^{pin 2 1} until between the forces including the component of the flow force due to the I mpulsänderung herx'scht of the flowing medium equilibrium, the pressure reaches the chamber 10 ^for the via the pilot system 47 *, and thus the pressure difference between the spaces 21 * and 22 * set pressure, so the piston 5 shifts' due to the spring force of the spring 35 * and the seat element 1 ¹ closes the throttle 31!

If the pressure in space 10 * exceeds the one-part pressure, the force resulting from the product of the area difference between surfaces 28 and 30 ^f and the pressure in space 10 * and the force resulting from the pressure in space 22 * and the Surface 29 * resulting force the piston 5 * against the force resulting from the pressure in the space 21 * and the surface 27 * and the force of the spring 36 * ι whereby the lever 9 * pivots about its pivot point 65 * and over the Transmission pin 4 *, the seat element 3 * is moved and thus the throttle 32 * is opened. Thus, the pressure in the room 10 * and thus in the line 38 * is regulated a piston, e.g. piston 6 * can be dispensed with «,

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In this way it is possible to e.g. B · to create a pilot-operated pressure reducing valve with secondary pressure limitation »Such a valve can also be designed as a direct-operated valve, if z« B «in space 21 * an adjusting spring acts on piston ^5f and piston 6 * is omitted. by series connection or parallel connection of several seat elements to the existing additional hydraulic functions to realize such · B _e Druckzuschaltfunktion of another operation after reaching the desired pressure in the space 38 '·

In Figure 3 an example of application of a pressure reducing valve is shown with the secondary pressure limiting * This control variant ^ft provided a fully hydraulically operated injection molding machine with a regulating pump and a separate control oil circuit 41 for controlling the injection movement of the injection pressure, holding pressure and dynamic pressure · from the control pump must be independent of the Injection pressure, back pressure and back pressure, the closing pressure, can be kept at a level above the injection pressure, back pressure and back pressure. By switching the magnet 49 **, the directional valve 48 ^{ft is moved} from the overflow position into the switching position of the pressure limitation of the injection pressure, i.e. the pressure limiting valve 50 "becomes effective. The maximum set injection pressure builds up in space 22", with the piston 5 "shifting and pushing open the seat element 1" via the actuating pin 8 "and thus the oil flow from space 15" to space 10 "and 11" takes place · This initiates the injection movement · In this case, the device according to the invention fulfills the control function of a piloted directional valve · After the injection process has taken place, a pressure builds up in the injection cylinder and thus in space 10 "and 11" Switching to holding pressure takes place, which corresponds to the injection pressure setting in space 22 ", with the piston 5" shifting back into its central position and the seat element 1 "blocking the flow of oil to space 10" »

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If the pressure in the space 10 "to the set value, the spring force of the spring 36 in the set" has to be considered, then the piston 5 "'and of the actuating pin 7" displaces lifts the seat member 3 "itz from ^s, and up to reaching of the pressure equilibrium between the pressure in space 22 "and 10", oil can flow from space 11 "into the outlet 16". If "the magnet 53" is switched on, the pressure relief valve 55 ", which is set to a lower pressure in this application, takes effect for the holding pressure, the pressure in the space 22" being reduced and the pressure in the space 10 "moving the piston 5" the transfer pin 7 "pushes the seat element 3" and thus causes a pressure reduction in the spaces 10 "and 11", and thus the new setting is realized in the injection cylinder , d. h · Oil is displaced from the injection cylinder. By switching the magnet 54 ", the back pressure relief valve 56" is switched on and the oil flowing back from the injection cylinder via line 38 "can, while maintaining the desired back pressure, by moving the piston 5" and lifting it of the seat element 3 "drain into the outlet 16" · After the plasticizing process, the magnet 49 "is switched off and the space 22" is depressurized so that the dynamic pressure relief is carried out, that is, the spaces 10 "and 11" are almost pressureless. The pressure in the spaces 10 "and 11" is only determined by the spring 36 "in the space 13" ~ the control oil flow from space 15 "can also be branched off via a throttle ·

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Claims (1)

Claims 1 Hydraulic control and regulating device for controlling and regulating oil flows and / or hydraulic pressures, in particular for hydraulic circuits in injection molding machines, which is way, servo, pressure differential, pressure switching, pressure limiting, pressure reducing, two-way or three-way flow control - and / or flow dividing function, characterized in that one or more seat elements (1) (1 ^f ) v (1 ") i (2), (3)» (3 ¹ ) (3 ") t W located in the housing (61), (61 *) f (61 ") in one direction and in the other direction on a seat (31), (31 ¹ ), (31") »(32) (32 ¹ ), (32 ")» (33), (34) rest with both sides (23), (23 ^f ), (23 ") and (24), (24 ·), (24") or (25), (25 *), (25 ") and (26), (26 *), (26") are hydraulically connected to each other, so that the same pressure prevails on both sides that a spring (35), (350, ( 35 "), (36), (36 *), (36") presses onto the seat and mechanically uses an actuation system to perform the above-mentioned functions are pushable, the actuation system being hydraulically, pneumatically, electrically or mechanically controllable and preferably consisting of a piston system with one or more pistons (5), (5 *), (6 ^f ), (5 "), which are dependent on the control - or control task can be pressurized on one or both sides and via a piston rod (7), (8), (7 "), (8") or a lever system (9 ¹ ) with the seat elements (1), (2) available, (3), (4), (1 *), (3 ¹⁾ "(1"), (3 ") in ^w irkverbindung, wherein by the operating system, the seat elements (1), (2), (3) , (4), (1 «), (3 ¹ ), (1"), (3 ") and thus hydraulic connections via throttle edges (31), (32), (33), (34), (31 ¹ ), (32 *), (31 ") (32") can be opened and the size of the throttle gap (31), (32), (33), (34), (32 ^f ), (31 ¹ ), (31 "), (32") can be controlled for the solution of certain regulating tasks or can be regulated independently via a comparison element containing the piston system, for controlling and regulating the piston system ms preferably pressure relief valves, directly controlled, pilot controlled, electrically adjustable via servomotor or regulating magnet, servo systems z «, B« nozzle flapper systems, directional control - 2 - 609812/0956 251Q667 tile for connection and disconnection, Drosselsysterne or other systems for switching on and off or ₀ Change of pressures and adjustable springs are used · 2 · Hydraulic control and regulating device according to claim 1, characterized in that the mechanical actuation system is hydraulic, can be controlled pneumatically, electrically or mechanically 3 · Hydraulic control and regulation device according to claim 1, characterized characterized in that the control mechanism is a piston system 4 · Hydraulic control and regulating device according to claims 1 to 31 characterized in that the seat elements have a piston which can be acted upon by control oil on one or both sides (5) (5 ") can be actuated. 5 "Hydraulic ^ expensive and control device according to claim 1 to 4, characterized in that the control mechanism. a stepped piston represents » 6 Hydraulic control and regulating device according to claims 1 to 4, characterized in that a plurality of pistons are seated on a piston rod, which pistons can be selected individually or simultaneously can be pressurized on one or both sides 7ο Hydraulic control and regulating device according to claim 1 to 3 »characterized in that a lever system (9 ¹ ) can be actuated by one or more pistons (5 ^f ), (6 ¹ ), with a form-fitting or only there is a non-positive connection in one direction. 8 «Hydraulic control and regulating device according to claims 1 to 3 and 7» characterized in that the number of pistons (5 *)> (6 ¹ ) is variable » - 3 609812/0956 Jib 9. Hydraulic control and regulating device according to claim 1 and 8, characterized in that the diameter of mutually acted upon, a common control task solving piston (5 *) f (6 ¹ ) are different. 10 · Hydraulic control and regulating device according to claim 1 to 3, characterized in that the piston system consists of several separate pistons, which the seat elements (1), (2), (3), (4), (1 ¹ ), ( 3 ^f ) i (1 ^M ) i (3 ") confirm. 11. Hydraulic control and regulating device according to claim 1 to 3i, characterized in that the locking force of the / of the seat element (s) (1), (2), (3), W, (1 ¹ ), (3) by an additional piston system ¹ ), (1 ") t (3") is changeable. 12. Hydraulic control and regulating device according to claim 1 to 3i, characterized in that the number of seat elements (1), (2), (3), W ₉ (1 ^f ) f (3 ¹ ) »(1") i ( 3 ″), which are connected to one another in a form-fitting manner or non-positively to the control device in one direction, both one behind the other and next to one another. 13 · Hydraulic control and regulating device according to claims 1 and 3i characterized in that a spring loads the piston system. 14. Hydraulic control and regulating device according to claim. 1 _f characterized in that the control mechanism is a magnet system.