Control valve having switchable control edge

Abstract

The invention relates to a control valve having a switchable control edge, and comprising a valve body (1) having a first control slide (400) and at least two control terminals (501; 502; 503; 504; 505) and at least one control edge (6; 44; 45), wherein the first control slide (400) has an axial bore (40) and a second control slide (41) is formed in the axial bore (40); and further comprising an end cap (57) having an actuating piston (48), wherein the actuating piston (48) is designed to engage in the axial bore (40), and the actuating piston (48) is designed to move the second control slide (41) in the axial bore (40).

Description

[0001] Control valve with switchable control edge

[0002] The object of the invention is to integrate an actuating mechanism into an existing control valve which, on the one hand, enables a small relative overlap between the control edges PA and AT of a control valve during control operation and, on the other hand, separates the A connection from the T connection during standstill (failsafe case).

[0003] In applications where hydraulically pilot-operated 4 / 3-way control valves with a piston-type longitudinal slide valve (manifold-mounted valve design) are used, it is necessary to prevent movement of the axis of, for example, an injection unit of a plastic injection molding machine, which is controlled or regulated by the control valve, during standstill (failsafe). Particularly critical in this case is the outward movement of the injection cylinder, which must be avoided at all costs.

[0004] This is generally achieved by ensuring that the P control edges for connecting the pressure supply are sufficiently covered in the failsafe case in order to prevent a fluid volume flow into the consumer or at least to reduce it to a minimum.

[0005] To prevent the injection cylinder from retracting, an AT control edge must also be designed to overlap the consumer, e.g., the injection unit, to prevent fluid flow to the tank. This prevents external forces acting on the axis from causing it to move unintentionally. Slide valves always exhibit a gap leakage inherent in their design.

[0006] The failsafe condition represents a safe machine state in which the control valve is not in active electronic control – it is usually de-energized and de-energized, and the control spool is not in active position control. In a failsafe condition, the control spool is moved to a final position or defined position via mechanical failsafe mechanisms, such as springs and / or end stops, and switching valves.

[0007] On the other hand, in (control) operation, the smallest possible overlap at the PA control edge and AT control edge of the control valve is required in order to be able to carry out precise axis position / pressure or force controls.

[0008] The problem is that both requirements contradict each other.

[0009] Either the control spool is manufactured with a small overlap or even a zero intersection of the control edges PA and AT, which enables precise control but results in a retracting drift movement of the axis of an injection machine in the failsafe case (since the AT control edge then already shows an under-coverage), or the control spool is manufactured with overlapped control edges, e.g. the PA and AT control edges, which results in imprecise control but ensures a standstill or a sufficiently small movement of the axis when at a standstill (failsafe case).

[0010] Overlapped control spools are known, which are electronically compensated in active control, so-called deadband compensation, but this reaches its dynamic limits. Ultimately, to control a pressure or flow rate in a working port, the physical overlap of the control edges must always be traversed. Depending on the size of the overlap on the control spool (deadband to be traversed) and the dynamics of the pilot valve, this can lead to degradation of the control result, as traversing the overlapped area takes a certain amount of time.

[0011] It is also known to connect safety valves, usually seat valves, in series with the control valve to decouple the consumer connections or the pressure supply from the control valve. Seat valves connected in series require additional installation space. They must be dimensioned accordingly, as they must be adapted to the maximum flow rate of the control valve. They are usually selected one nominal size larger to keep pressure and thus energy losses low during operation. A disadvantage is that, depending on the switching dynamics of the control valve, the seat valve seals can be subjected to considerable stress, which increases maintenance costs and time. Furthermore, additional seat valves represent an additional cost factor.

[0012] Another well-known approach is to use separate control valves to control / regulate the two ports of the actuator separately.

[0013] Accordingly, an individual failsafe position can be set for each of the separate control valves, as required by the application. The disadvantage of this solution is that two or more control valves are required, which makes the solution expensive. Furthermore, the control system is more complex.

[0014] Based on the known prior art, it is an object of the present invention to provide a control valve with control edges which at least partially overcomes the disadvantages present in the prior art. In particular, it is an object to integrate an actuating mechanism into an existing control valve which, on the one hand, enables a slight relative overlap between the control edges PA and AT during (control) operation, thus enabling precise control, and, on the other hand, additionally separates the A port from the T port when at a standstill (failsafe case, where the A port is already separated from the pressure supply P by an overlapped PA edge), i.e. has sufficient overlap to ensure that the axis remains stationary or that the axis movement is sufficiently small.

[0015] This object is achieved by the subject matter of the independent patent claims. Advantageous embodiments of the invention are described in the dependent patent claims and the following description.

[0016] A control valve with a switchable control edge can comprise a valve body and an end cap with an actuating piston. The valve body can be formed with a first control spool and at least one first and second control port and at least one control edge. The first control spool can have an axial bore, and a second control spool can be formed in the axial bore.

[0017] A control valve can be a valve, in particular a hydraulic valve, that influences the pressure fluid via the flow path, direction and magnitude of the volume flow, or the fluid pressure. According to the disclosure, it is a directional control valve with the structure and design of the active surface (sealing surface) of a slide valve with the active movement of a longitudinal valve.

[0018] A control edge can be a movable edge in a valve that regulates the flow of liquids or gases between the ports on the valve. It is actuated by a force, e.g., a lever or an electric and / or pneumatic actuator, and works by opening or closing a flow channel between two control ports in the valve body. In particular, the movable edge is a surface of the first and / or second control spool that can cover an opening of a flow channel of one and / or more control ports of the valve body, thereby partially or completely opening and / or blocking a passage or flow path between control ports.According to the invention, the valve body and the control spools form coordinated control edges that are displaceable coaxially relative to one another, so that when the respective openings of the control ports in the valve body are arranged opposite one another, a flow path is created and / or throttling occurs. A control valve according to the disclosure can comprise at least three control edges. A first control edge can be a control edge of the piston-type spool design known from hydraulically pilot-operated 4 / 3-way valves, which regulates the flow between the control ports A and T. A first control edge can be a first AT control edge, which can also be referred to as an A-T1 control edge.

[0019] A second control edge may be a novel control edge according to the disclosure that, in addition to the first control edge, controls the flow between the control ports A and T. The second control edge may be a second AT control edge, which may also be referred to as an A-T2 control edge.

[0020] According to the invention, the third control edge corresponds to a first control edge and can be controlled by an axial displacement of the first control spool such that the third control edge partially or completely opens and / or partially or completely closes the passage between the control ports P and A. This allows the flow between the two control ports P and A to be controlled and regulated. A third control edge can also be referred to as a PA control edge.

[0021] A fourth control edge may be a control edge that regulates the flow between the control ports P and B. The fourth control edge may be referred to as the PB control edge.

[0022] A fifth control edge may be a control edge that regulates the flow between the control ports B and T. The fifth control edge may be referred to as the BT control edge.

[0023] A control edge can be switchable. A switchable control edge can open and / or close the flow paths between the control ports in the valve body by actuating and adjusting the first and / or second control spool. According to the disclosure, this can be achieved by an electric, pneumatic, or hydraulic and / or piezoelectric or magnetostrictive actuator. A switchable control edge can enable rapid response to changes in the system and precise control of the flow of liquids or gases by being able to be precisely switched from one position to another and, in the active position, enabling a zero intersection between the control edges PA and AT.

[0024] A control port of a control valve according to the disclosure may be a port in the valve body. The control port may open into an annular channel in the valve body. For example, the line of a

[0025] Pressure supply X of a pilot valve, and / or the return Y to the tank, and / or the pressure supply P of the valve body, and / or a further return T to the tank and / or at least one working connection A, B can be connected.

[0026] A first control port may be a T-control port. A second control port may be an A-control port. A third control port may be a P-control port. A fourth control port may be a B-control port. A B-side T-ring channel may be a space that, in the longitudinal section of the valve body, is connected to the first control port via a channel, in particular a tank bridge, to the right of the B-control port. This channel may be a B-side T-channel.

[0027] A first and a second control spool according to the disclosure may be a hydraulic control spool. The control spools may be used in directional control valves of the spool valve type. The second control spool may be formed within the first control spool according to the disclosure. The actuation direction of the two control spools is coaxial along their longitudinal axes, so that the respective control edges of the control spools completely, partially, and / or not at all cover the openings of the control ports in the valve body, depending on the position of the displaced control spool.

[0028] The first and second control spools can each comprise at least two piston shoulders on the piston shaft, which form the control edges on the control spool. The first control spool can form a first and second piston shoulder. The first control spool can also form a third piston shoulder. Furthermore, the first control spool can form a fourth piston shoulder. The second control spool can also form a first piston shoulder and a second piston shoulder. Depending on the position of the first and / or the second control spool, the piston shoulders can cover control connection openings in the valve body and thus regulate the flow between the control connections. The piston shoulders of the control spools can be arranged in a connection area of ​​the control connections. A piston shoulder of a control spool, which covers a control connection opening depending on the setting, can form a control edge with this opening in the valve body.

[0029] An axial bore is a bore in the valve body and in the first spool along a longitudinal axis of the first spool, such that the first spool is slidably received in the bore of the valve body and the second spool is slidably received in the bore of the first spool. The bore can be centered in the spool. Furthermore, according to the disclosure, the control valve with a switchable control edge can have an end cap with an actuating piston. In this case, the actuating piston can be configured to engage the axial bore and can also be configured to displace the second spool in the axial bore of the first spool.

[0030] This allows a second control edge to be controlled between the control ports T and A. The second control edge can result in the disclosed control valve combining the functionality of two valves. On the one hand, with activated fail-safe valves, zero-cut behavior and thus good controllability of the axis connected to the valve can be ensured; on the other hand, with deactivated fail-safe valves, leakage can be reduced to a minimum, which can correspond to the gap leakage. A second (seat) valve connected in series can become unnecessary. This can lead to cost, service / maintenance, and installation space savings. Furthermore, this component does not need to be kept as a spare part. According to the disclosure, a second (seat) valve, which is otherwise usually connected in series (downstream / downstream), and which can cause a (continuous) pressure loss, can be omitted.A control valve system with the control valve according to the disclosure can be more energy efficient than the combination of control valve and series-connected (seat) valve known from the prior art.

[0031] A connecting element can be formed between the actuating piston and the second control spool. This allows axial and angular misalignments to be compensated.

[0032] A connecting element can comprise a compensating rod and at least two locknuts. A first locknut can be locked against the second control spool. A second locknut can be secured against an actuating piston. The second locknut can be designed as a mechanical stop and be hardened. The connecting element between the actuating piston and the second control spool can fulfill a coupling function and therefore be a coupling element.

[0033] This allows a manufacturing-related axial offset of the actuating piston and the second control spool running in the first control spool to be compensated.

[0034] Furthermore, the valve body and the first control spool of the control valve can form a first (A-T1) and a second control edge (A-T2). A slight relative overlap can be formed between the second control edge (A-T2) and a third control edge (P- / ). The first control edge (A-T1) can have sufficient overlap.

[0035] The second control spool can also be configured to control the second control edge (A-T2) independently of the first control spool, i.e., to open or close it. According to the disclosure, a precise actuating mechanism can thus be integrated into the control valve using the second control edge (A-T2). At the same time, during standstill (failsafe), a flow path from one control port to the next control port can be prevented by sufficiently covering the first control edge (A-T1), thus preventing an incoming drifting movement of an axis, for example, of an injection molding machine.

[0036] A flow path can be formed between at least two control connections and can be influenced by a control edge in such a way that the flow rate can be regulated.

[0037] According to the disclosure, an overlap can be a positive overlap, a zero overlap, or a negative overlap. A positive overlap can describe the control edge position of a piston shoulder of the first and / or second control spool, the length of which is greater than the width of the opening of the annular channel of the control ports in the housing of the valve body.

[0038] The overlap refers to the total stroke of the first or second control spool in the center position or end position and can be specified in percent [%].

[0039] Zero overlap (zero cross-section) can be characterized by the flush position of the control edges of the piston shoulders of each of the two control spools and the annular channels of the control ports in the valve body housing. Zero overlap of control edges can achieve very short actuation or response times for the actuator connected to the control valve, since the opening cross-section of the annular channel of the respective control ports in the valve body is released without delay, and only small actuation travels are required for actuation and control.

[0040] Negative overlap can describe the control edge length of a piston shoulder of the respective control spool, whose length is smaller than the width of the annular channel of the control ports in the valve body housing. Negative overlap can be an under-interference. Low overlap can occur if the overlap of a single control edge is between 0% and 5%. A low overlap of 0% can be a zero-interference.

[0041] A relative contact can be the ratio between two contact points. For example, the contact point of one control edge and the contact point of another control edge are added together. This sum can result in a relative contact point.

[0042] The relative overlap may be a low relative overlap if the sum is between 0% and 10%. The second control edge (A-T2) may form such a low relative overlap with the third control edge (PA).

[0043] A large overlap of an individual control edge can be 10% or more. A sufficient overlap and / or a sufficiently large overlap can be between 10% and 20%. The first control edge (A-Tl) can have such a large overlap and / or sufficient overlap. The third control edge (P-A) can also have a large overlap. A large and / or sufficiently large overlap ensures the stopping or a sufficiently small movement of an axis / actuator, e.g., an injection unit, in the event of a failsafe. The PA control edge (third control edge) can have a large overlap.

[0044] According to the invention, a negative overlap and / or undercoverage of a single control edge is less than 0%. The fifth control edge (BT control edge) can have such an undercoverage.

[0045] The second control edge (A-T2 control edge) can have a groove-shaped annular channel. The groove-shaped annular channel can be machined into the piston shoulder. Instead and / or additionally, the second control edge can have one or more control windows distributed around the circumference.

[0046] The grooved annular channel and the control window(s) are formed at the inlet and outlet of a transverse bore of the first control spool, respectively. Both can have different shapes. For example, the grooved annular channel can have a rectangular cross-section or a cross-section with rounded corners at the base. Control windows can also have different cross-sectional shapes, e.g., rectangular, triangular, round, or T-shaped.

[0047] The annular channel or the control window(s) can be manufactured to be axially precisely adapted to the third control edge (A-T2) in the valve body, in particular to the third control edge (PA), for specific application requirements. This allows the second control edge (A-T2) to enable precise control. Furthermore, according to the disclosure, the second control edge (A-T2) can separate the control port A from the control port T in the failsafe case, since the second control edge (switchable via the inner second control spool) and the first control edge (A-T1) can be brought into a position together so that, viewed from the outside, sufficient overlap can be achieved at the first (A-T1), second (A-T2), and third (PA) to ensure standstill or a sufficiently small movement of the axis.

[0048] The annular groove or the control window(s) of the second control edge (A-T2) can be connected to the axial bore in the first control slide via at least one first transverse bore.

[0049] The first transverse bore can be formed in a first piston shoulder of a plurality of piston sets of the first control spool. The first piston shoulder can have a plurality of first transverse bores. The first transverse bore(s) can be formed perpendicular to the longitudinal axis of the axial bore of the first control spool. In a longitudinal section through the valve body of the control valve, the first piston shoulder of the first control spool is formed on the farthest left. The second control edge (A-T2) can be arranged in the first piston shoulder.

[0050] The first transverse bore(s) can form the second control edge (A-T2) in the first piston shoulder. Thus, the first transverse bore(s) can result in the disclosed control valve combining the functionality of two valves. On the one hand, with activated fail-safe valves, zero-cut behavior and thus good controllability of the axis connected to the valve can be ensured; on the other hand, with deactivated fail-safe valves, leakage can be reduced to a minimum, which can correspond to the gap leakage. A second (seat) valve connected in series can become unnecessary. This can lead to cost, service / maintenance, and installation space savings. Furthermore, this component does not need to be kept as a spare part. According to the disclosure, a second (seat) valve, which is otherwise usually connected in series (downstream), and which can cause a pressure loss or continuous pressure loss, can be omitted.A control valve system with the control valve according to the disclosure can be more energy efficient than the combination of control valve and series-connected (seat) valve known from the prior art.

[0051] The first control spool can form at least one second transverse bore in the connection area of ​​a second control port (A) of the valve body. Additionally, the at least one second transverse bore can be connected to the axial bore of the first control spool.

[0052] A connection area can be a part of the valve body through which liquids or gases can flow in or out. Connection areas can be formed externally on the valve body and have a defined connection diameter to enable a secure connection to control blocks, pipes, containers, or other system components. The connections can have various forms, including threads, flanges, or plug-in connections. The connection area can be designed so that the connection area extends into the valve body.

[0053] This can result in the second control edge (A-T2) in the first piston shoulder of the first control spool being connected to the second transverse bore via the axial bore. The second transverse bore can represent a flow inlet in a second piston shoulder of the first control spool, but can also alternatively form another control edge to the second control spool (which is part of an internal system of the first control spool). This alternative additional control edge can regulate the flow between the control ports A and T via the second control edge (A-T2).

[0054] According to the disclosure, the actuating piston may be configured to control a flow path via the second control edge (A-T2) by means of the second control slide.

[0055] The term "via the second control edge" can mean that the flow path from one control port to another control port is opened. For this purpose, the axial displacement of the first and / or second control spool can cause the corresponding control edge to open the flow path between two control ports, thus regulating the flow rate.

[0056] This can lead to precise control of the disclosed control valve, since a small relative overlap is achieved between the second control edge (AT2) and the third control edge (PA) during control operation. In a failsafe situation, however, control port A can be separated from control port T by ensuring that the first control edge (AT) and the third control edge (PA) achieve a sufficiently large overlap, thus ensuring axial standstill or a sufficiently small axial movement. For hydraulic compensation, the second control spool can have two surfaces with equally large effective areas.

[0057] The surfaces can be ring-shaped or circular. The surfaces can each be formed on a piston shoulder of the second control spool.

[0058] A load pressure applied to the second control port (A) cannot therefore lead to the second control spool being actuated unintentionally. This, in turn, can enable precise control of the control valve according to the disclosure. In a failsafe situation, the second control port (A) can be separated from the first control port (T) by ensuring that the first control edge (A-Tl) and the second control edge (PA) achieve a sufficiently large overlap, thus ensuring an axis standstill or a sufficiently small axis movement in a failsafe situation.

[0059] According to the disclosure, the axial bore of the first spool may include a chamber with an internal compression spring.

[0060] The chamber may be formed in the longitudinal section of the valve body as an extension of the right end of the axial bore. A rear portion of the axial bore may encompass the chamber. The chamber may be located in the first control spool at a height between a second and third piston shoulder of the first control spool. The chamber may be formed at the level of the third port (P).

[0061] This can serve to accommodate a spring and, in an end position of the first and / or second control spool, form a stop for the second control spool. This can enable precise control of the control valve of the disclosure. In a failsafe situation, control port A can be separated from control port T by ensuring that the first control edge (A-Tl) and the second control edge (PA) achieve a sufficiently large overlap, thus ensuring that the axis remains stationary or that the axis movement is sufficiently small.

[0062] According to the disclosure, an axial relief bore can be formed coaxially with the axial bore. The first control spool can have at least one third transverse bore in the region of the B-side T-channel, which is connected to the axial relief bore. The B-side T-channel and the third transverse bore can form a leakage flow path.

[0063] The third transverse bore according to the disclosure can be formed perpendicular to the axial relief bore. The third transverse bore can divert leakage from the internal system (the chamber of the axial bore of the first control spool). This can enable precise control and actuation of the control valve and, in addition, during standstill (failsafe situation), flow from one control port (A) to the next control port (T) can be prevented by sufficiently covering the first control edge (A-Tl). This, together with the third control edge (PA) covered in the failsafe situation, can ensure axial standstill or a sufficiently small axial movement.

[0064] The second control spool may be provided with a slot on its right-hand end face. This slot can divert leakage.

[0065] The right end face may be formed in a second end region of the second control spool. A left end face of the second control spool may be formed in a first end region of the second control spool. The left end face and the right end face may be formed at opposite end regions of the second control spool.

[0066] When blocked, the slot allows leakage from the chamber to be vented from the axial bore. This prevents pressure from building up in the chamber of the first control spool due to leakage volume flows and causing the second control spool to open unintentionally. Thus, the disclosed control valve can enable a precise control mechanism and, in the event of a failsafe condition, separate the second control port (A) from the first control port (T). In this case, the leakage can be vented via the slot while still ensuring axial standstill.

[0067] The end cap may include a valve and a spring chamber. The spring chamber may include a compression spring and a stop.

[0068] The spring chamber and the end cap can be mounted on the left side of a first end of the valve body in a longitudinal section of the valve body. Depending on the application, the end cap and the spring chamber can also be mounted on the right side of the valve body of the disclosed control valve.

[0069] The end cap can enable a precise control mechanism in the disclosed control valve by means of the actuating piston. Due to the precise control, in the failsafe situation, the second control port (A) can be separated from the first control port (T) by the first control edge (A-Tl) and the third control edge (PA) forming sufficient overlap to ensure a stationary axis or a sufficiently small axis movement. The spring chamber of the disclosed valve body can be connected to the valve body via a relief bore.

[0070] The relief bore can lead out of the spring chamber and end at the valve body, where the relief bore can continue. This creates a complete passage and allows a flow path toward a tank via the T-port.

[0071] The spring chamber can thus be constantly relieved towards the tank and precise control of the control valve can be ensured.

[0072] The control valve of the disclosure can be used as an injection control valve for controlling an injection unit of an injection molding machine.

[0073] During normal operation, precise control of the injection molding machine can be enabled and, in the event of a failsafe, a safe machine state of the injection molding machine, in particular an axis standstill, can be achieved.

[0074] A control valve system may include a pilot valve, one or two failsafe valves, and a control valve of the disclosure. A failsafe valve may be a safety valve.

[0075] The advantage is that both in control operation a small relative overlap between the second (A-T2) and third (PA) control edge is enabled, which leads to precise control and on the other hand in the failsafe case the A connection is separated from the T connection, i.e. the first control edge (A-Tl) and third control edge (PA) have a sufficient overlap, and thus enables a safe machine state of the control valve system in the failsafe case.

[0076] The control valve system can ensure precise controllability of the injection molding machine's axis when the failsafe valves are activated. When the failsafe valves are deactivated, the control valve system can reduce leakage to a minimum, which can correspond to the gap leakage, and ensure axis standstill or a sufficiently small axis movement in the event of a failsafe condition. The control valve system with the control valve according to the disclosure can be more energy-efficient than the control valves known from the prior art.

[0077] The above embodiments and further developments can be combined with one another as desired, where appropriate. Further possible embodiments, further developments, and implementations of the invention also include combinations of features of the invention not explicitly mentioned above or described below with regard to the exemplary embodiments. In particular, the person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the present invention.

[0078] The present invention will be explained in more detail below with reference to the exemplary embodiments shown in the schematic figures of the drawings. In the drawings:

[0079] Figure 1 Control valve state of the art

[0080] Figure 2 Application example in the state of the art

[0081] Figure 3 Volume flow signal function of a control valve in the state of the art

[0082] Figure 4 Schematic representation of a control valve in control operation in the state of the art with zero cut

[0083] Figure 5 Schematic representation of a control valve in fail-safe position in the state of the art with overlap and under-cover

[0084] Figure 6 Schematic representation of the control valve according to the disclosure in control operation with the second control spool open

[0085] Figure 7 Schematic representation of the control valve according to the disclosure in failsafe position with closed second control spool

[0086] Figure 8 Volume flow signal function of a control valve according to the disclosure

[0087] Figure 9 Schematic representation of the control valve according to the disclosure in failsafe position with closed second control spool

[0088] Figure 10 Schematic representation of the control valve according to the disclosure in Regulation

[0089] Figure 11 Schematic representation of the control valve according to the disclosure in controlled negative end position

[0090] Figure 12 Schematic representation of the control valve according to the disclosure in controlled positive end position

[0091] Figure 13 Alternative control valve according to the disclosure in controlled negative end position Figure 14 Detail of a schematic representation of the left end cap of the control valve from Figure 17 according to the disclosure

[0092] Figure 15 Further schematic representation of the control valve in the failsafe case

[0093] Figure 16 Schematic representation of the control valve system according to the disclosure with valve electronics and position measuring system in failsafe position with closed second control spool

[0094] Figure 17 Schematic representation of the control valve system according to the disclosure with valve electronics and position measuring system in control

[0095] Figure 18 Schematic representation of the control valve system according to the disclosure with valve electronics and position measuring system in controlled positive end position

[0096] Figure 19 Schematic representation of the control valve system according to the disclosure with valve electronics and position measuring system

[0097] The accompanying drawings are intended to provide a further understanding of embodiments of the invention. They illustrate embodiments and, in conjunction with the description, serve to explain principles and concepts of the invention. Other embodiments and many of the noted advantages will be apparent upon review of the drawings. Elements of the drawings are not necessarily shown to scale relative to one another.

[0098] In the figures of the drawing, identical, functionally identical, and acting elements, features, and components are provided with the same reference symbols unless otherwise stated. In particular, Figures 6 to 14 build on one another, which is why identically acting elements, features, and components are not provided with all reference symbols for clarity unless otherwise stated. However, a person skilled in the art will recognize that these are identically acting elements, features, and components and can add the corresponding reference symbols from the previous figure.

[0099] Finally, it should be noted that the description of the invention and the exemplary embodiments are not intended to be restrictive with regard to a specific physical implementation of the invention. All features explained and shown in connection with individual embodiments of the invention can be provided in different combinations in the subject matter of the invention in order to simultaneously realize their advantageous effects. The scope of protection of the present invention is defined by the claims and is not limited by the features explained in the description and / or shown in the figures.

[0100] Figure 1 shows the schematic structure of a pilot-operated 4 / 3-way control valve known in the prior art. It consists of a valve body 1, also known as the main stage, an optional fail-safe valve 2, also known as a safety valve, and a pilot valve 3. A movable control spool 4 is housed in the valve body 1. The control spool 4 in Figure 1 forms four piston shoulders. A first piston shoulder 31, a second piston shoulder 32, a third piston shoulder 33 and a fourth piston shoulder 34. The valve body 1 and the piston shoulders 31, 32, 33, 34 of the control slide 4 in Figure 1 have coordinated control edges, for example the control edges 5 and 6 between the control connections T and A. The valve body 1 forms a fixed control edge 5 and the second piston shoulder 32 of the control slide 4 forms a movable control edge 6, since the control slide is arranged displaceably in the valve body 1.Depending on the position of the control slide 4 within the valve body 1, the second piston shoulder 32 opens a flow path between the control connections T and A and between A and P.

[0101] When the fail-safe valve 2 is switched off, the control slide 4 is pressed into a predetermined central position by compression springs 7 and a mechanical stop, shown in Figure 1 by adjustable discs 8 in the control chambers 12, 13, and closes the corresponding control connections 9 (T, A, P, B) of the valve body 1 with the piston projections 31-34.

[0102] The valve body 1 has the following control connections 9:

[0103] • X - Pressure supply of the pilot valve 3 and is optional

[0104] • Y - return or tank connection pilot valve 3, also optional

[0105] • P - Pressure supply of valve body 1

[0106] • T - Return or tank connection valve body 1

[0107] • A and B - working connections to which the consumer, e.g. the injection cylinder 16 of an injection unit 15 of an injection molding machine, is connected.

[0108] Attached to the left side of the valve body 1 is an end cap with electronics for controlling the control chambers 12 and 13. The end cap comprises a position measuring system 10 and valve electronics 11. The position of the control spool 4 is measured by means of the position measuring system 10 and controlled by valve electronics 11.

[0109] The left control chamber 12 and the right control chamber 13 of the valve body 1 are supplied with volume flow and pressure via the pilot valve 3. Depending on the electrical control of the pilot valve 3, the control spool 4 is deflected to the left or right from the center position, thus opening the corresponding flow paths PA and BT or PB and AT.

[0110] Figure 2 shows a schematic representation of an injection unit 15 with a control valve, which is an injection control valve 14. In this application example of the invention, the control valve 14 controls the injection unit 15 of an injection molding machine. If the machine's protective grille is opened, the failsafe condition occurs, and the control valve must be brought into a safe state. The injection cylinder 16 must under no circumstances move the injection unit 15 forward and thereby extend it. This means that the working connection of the control valve, which is connected to the cylinder chamber / surface 17 of the injection cylinder 16, which enables the injection movement, must under no circumstances be pressurized.

[0111] During the plasticizing of the plastic melt or during setup mode, an external force is exerted by the plastic melt in the injection cylinder, causing it to move in the opposite direction to the injection motion. In certain applications, especially during setup mode with the protective door open, this movement is undesirable for process-related reasons. To prevent this movement, the volume flow that can flow back from the axis to the tank via the control valve must be shut off or reduced to a sufficiently low level.

[0112] Injection control valves are often designed to control the volume flow or pressure of the piston side of the injection cylinder, which is connected, for example, to the A control port 502 of the control valve 1. An injection cycle is divided into the following phases and is illustrated by way of example in the volume flow signal function in Figure 3:

[0113] • "Injection" (via the PA control edge 20)

[0114] • "Pressure control" with decompression phase (via the PA control edge 20 and AT control edge 21)

[0115] • "Plastification" (suction via the BT control edge 22)

[0116] • "Retraction movement" of the injection cylinder (via the PB control edge 23 and AT control edge 21) Important for the process is the pressure control with decompression phase. This is significantly influenced by the geometric coordination of the PA control edge 20 and AT control edge 21.

[0117] The geometry of the control slide 4 in Figure 1, i.e. overlap of the individual control edges and resulting volume flow signal function, is adapted for each application.

[0118] The geometry of the 4 / 3-way control valve from Figure 1, particularly the overlap of the control edges, is schematically illustrated in Figures 4 and 5 using PI to P7. The corresponding applied volume flow is schematically illustrated in the characteristic curves 201, 211, 221, 231 of the control edges 20, 21, 22, 23 in Figure 3, correspondingly at PI to P7. Figure 4 shows a state-of-the-art control spool 4 in control operation with zero intersection PI of the control edges 20, 21, which enables good controllability. Figure 5 shows the same state-of-the-art control spool 4, but in a failsafe position. Compared to the position in Figure 4, the control slide 4 is shifted to the right so that the PA control edge 20 is covered P5, but the AT control edge 21 moves into an under-covered position P4 and the passage between the T and A control connections 501, 502 remains open.This is undesirable in the failsafe position 25 and is prevented by the switchable control edge according to the disclosure (Figures 6 to 14). Due to the undercovered position P4 on the characteristic curve 211, as shown in Figure 3, a volume flow is applied to the AT control edge 21, and due to the overcovered position, P5 on the x-axis and failsafe position 25 of Figure 3, no volume flow is applied to the PA control edge 20.

[0119] During normal operation in Figure 4, the PA control edge 20 between the P and A control ports 502, 503, together with the AT control edge 21 between the A and T control ports 502, 501, exhibits a slight relative overlap. In particular, the control edges 20, 21 in Figure 4 are designed with a zero cut PI, which is why the slight relative overlap from the two zero cuts from the control edges 20, 21 again results in a zero cut. The BT control edge 22 between the B control connection and the B-side T-channel 505 is largely under-covered, see P3 in Figures 3, 4 and the PB control edge 23 between the P and B control connections 503, 504 is largely over-covered, see also P2 in Figures 3, 4. As shown by P2 in Figures 3 and 4, the PB control edge 23 is over-covered, therefore no volume flow flows between the P and B control connections 503, 504.The very small relative overlap of the PA and AT control edges 20, 21, which are shown in Figure 4 with zero intersection, is shown in Figure 3 and Figure 4 using PI. The geometry of the control spool 4 in Figures 4, 5 can also be understood in the volume flow signal function in Figure 3. Figure 3 shows a volume flow signal function known from the prior art for the control valve and its control spool 4 from Figures 1, 2 and 4, 5 during control operation. The y-axis in Figure 3 shows the volume flow Q in liters per minute (Q [l / min]), while the x-axis represents the control spool stroke S, which corresponds to the distance traveled by the control spool 4 from Figure 1 in percent. The larger the percentage control spool stroke S, the more volume flow flows through the corresponding passages of the control ports T, A, P, B, since these are released by the control edges 20, 21, 22, 23 by a displacement of the control spool 4.

[0120] In Figure 3, -100% means a negative end displacement, which corresponds to a maximum displacement of the control spool 4 to the right in the valve body 1. Accordingly, a positive end displacement +100% means a maximum deflection of the control spool 4 to the left in the valve body 1. At the respective maximum deflection, stops at the corresponding end, for example, prevent further deflection of the control spool 4.

[0121] Figure 3 also shows the control spool stroke S and thus the overlap of the control edges 20, 21, 22, 23, with the characteristic curves 201, 211, 221, 231 representing the volume flow, particularly during the failsafe condition of a control valve in the prior art. In the failsafe position 25 during the failsafe condition, the control spool 4 assumes a defined spring-centered position when the failsafe valve 2, which is arranged between the pilot valve 3 and the valve body 1 in Figure 1, is deactivated. This failsafe position of the control spool 4 is indicated in Figure 3 by a dashed line 25 and is illustrated schematically in Figure 5.

[0122] The control spool 4 adjusts itself via corresponding adjustable mechanical stops 8 in the control chambers 12, 13 in Figure 1 such that the PA control edge 20 of the control spool 4 assumes an overlapped position in Figure 3, see intersection point P5 on the x-axis and the fail-safe position 25 shown in dashed lines in Figure 3. The AT control edge 21 consequently assumes an under-covered position relative to the valve body 1 (due to the very small relative overlap or the zero intersection of the PA and AT control edges 20, 21 from Figure 4), see intersection point P4 of the volume flow signal function 211 with the fail-safe position 25 in Figure 3 and Figure 5.During the failsafe case, the BT control edge 22 between the B control connection and the B-side T-channel 505 continues to be under-covered, see P7 in Figures 3, 5 and the P-B control edge 23 between the P and B control connections 503, 504 is still covered, see also P6 in Figures 3, 5 As a result, the piston surface of the injection cylinder 17 in Figure 1 is no longer subjected to supply pressure. This prevents, for example, the injection cylinder from extending. At the same time, fluid can escape from the injection cylinder via the open AT control edge 21 if it is subjected to an external force, such as during plasticizing or in setup mode when the injection cylinder is filled with molten plastic.

[0123] As already mentioned, according to the disclosure, an actuating mechanism is integrated into an existing control valve. To this end, good controllability during control operation is to be achieved through a low relative overlap between the PA and AT control edges 20, 21. In the failsafe case, the A control port 502 is also to be separated from the T control port 501 and simultaneously from the P control port 503 by overlapping AT and PA control edges.

[0124] To date, the only control valves known in the art are those with fast and precise control, which were manufactured with control edges as shown in Figures 3, 4 and 5. This means that control edges, ideally with a low relative overlap or zero intersection of the AT and PA control edges 21, 20 as shown in Figures 3 and 4, enable fast and precise control and, on the other hand, in the failsafe position 25, as shown in Figures 3 and 5, separate the A control port 502 from the P control port 503, i.e., have sufficient overlap of the PA control edge 20. However, these control valves with fast and precise control of the state of the art cannot, in the failsafe position 25, separate the T control port 501 and simultaneously the P control port 503 from the A control port 502 in order to ensure an axial standstill of the injection unit 15.

[0125] This is because, in the prior art, the geometry of the control spool of a control valve, in particular the width of the piston shoulders 31, 32, 33, 34 and thus the length of the control edges 20, 21, 22, 23, can no longer be modified after the valve has been manufactured and during operation. This means that during the failsafe event in the failsafe position 25, in valves with good controllability, only a separation of the P control port 503 from the A control port 502 is achieved, as shown in Figures 3, 4, and 5, instead of the desired simultaneous separation of the A control port 502 from the P and T control ports 503, 501.

[0126] To ensure that the width of the piston shoulder of the control spool 4 behaves as if it can be increased or decreased during operation, Figures 6 to 14 show switchable control edges according to the disclosure. Figures 6 and 7 in conjunction with Figure 8 schematically show how the width of the piston shoulders and thus the length of the AT and PA control edges can be switched between an overlap and a zero cut.

[0127] The control valve in Figure 6 is in active control mode. For this purpose, the first control spool 400, as shown in Figure 6, comprises an axial bore 40 with a second control spool 41 and at least a first and second transverse bore 46, 47 in the first and second piston shoulders 31, 32 of the first control spool 400. In addition to a first control edge 45 (A-T1) and a third control edge 44 (PA), a second control edge 42, 43 (A-T2) is formed. The first and third control edges 45, 44 correspond to the AT and PA control edges 21, 22 (as described with reference to Figures 3, 4, and 5). The second control spool 41 comprises a first piston shoulder 411 and a second piston shoulder 412 and regulates a flow or flow path through the transverse bores 46, 47 and the axial bore 40.The second control edge 42, 43 (A-T2) and the third control edge 44 (PA) simultaneously form a zero intersection, as shown by P8 and P11 in Figure 6, so that precise and fast control is possible with the second control spool in the open position, as shown in Figure 6. The first control edge 45 (A-T1) is in an overlapped position in Figure 6, P10 in Figure 6. Furthermore, Figure 6 shows that the second control edge 42, 43 (A-T2) and third control edge 44 (PA) together have a small relative overlap, in this case even a very small relative overlap, see P9 in Figure 6.This results in the characteristic curve 443 of the third control edge and the dashed characteristic curve 452 on the x-axis converging at a positive control stroke S, as shown in Figure 8 at points P8, P11, P9, so that depending on the movement of the first control spool 400 to the left or right in Figure 6 (see arrow symbols), a volume flow immediately occurs either between the T and A control ports 501, 502 or P and A control ports 503, 502. The volume flow between the T and A control ports 501, 502 occurs via the transverse bores 46, 47 and the axial bore 40 when the first control edge 45 (A-T1) is in the covered position. This still enables fast and precise control. In contrast to the prior art, the control is not carried out immediately via the AT control edge, which in Figure 6 would correspond to the first control edge 45 (A-T1) of the disclosure, but via the second control edge 42, 43 (A-T2) which is not known in the prior art.

[0128] The control spool 400 in Figure 7 is in a failsafe position during a failsafe event. The second control spool 41 is closed because the first piston shoulder 411 of the second control spool 41 prevents flow through the transverse bore 46, P12 in Figures 7 and 8. As a result, the second control edge 42, 43 (A-T2) is in a covered position and there is no flow between the T and A

[0129] Control ports 501 via the transverse bores 46, 47 and the axial bore 40. The first control edge 45 (A-Tl) and third control edge 44 (PA) are also overlapped in the failsafe position, P13 and P14 in Figure 7. This ensures that in the failsafe position 25 (see Figure 8), no volume flow can flow between the T and A control ports 501, 502 and the P and A control ports 503, 502. There is no flow path via the transverse bores 46, 47 and axial bore 40, nor is there a direct flow path from the A control port 502 to the T control port 501.

[0130] Figure 8 shows a volume flow signal function of the control edges from Figures 6 and 7 according to the disclosure. The x-axis shows the control spool stroke S of the first control spool 400 according to the disclosure. The failsafe position 25 passes through the origin and coincides with the y-axis. Figure 8 shows two cases of a characteristic curve of the volume flow between the A control port 502 and the T control port 501.

[0131] In the first case, with active control with the second control spool 41 open and the second and third control edges 42, 43; 44 (A-T2; PA) open, fast and precise control of the volume flow is possible via the second control edge 42, 43 (A-T2) and third control edge 44 (PA). If the first control spool 400 from Figure 6 is deflected to the right in the valve body 1, the volume flow between the T control port 501 and A control port 502 increases, as shown by the characteristic curve 452 in Figure 8, by creating a flow path via the second control edge 42, 43 (A-T2) and the transverse bores 46, 47 and the axial bore 40. From a certain further deflection to the right, the characteristic curve 452 no longer increases, since the maximum flow via the second control edge 42, 43 is limited due to the diameters of the transverse bores 46, 47 and axial bore 40.However, at P16 in Figure 8, the first control edge 45 (A-Tl) opens and an additional flow path between the T and A control ports 501, 502 is created, see characteristic curve 451. When the first control spool 400 is deflected to the left in Figure 6, i.e. from P8, Pli, P9 to the right in Figure 8, a flow path opens between the P and A control ports 503, 502 while simultaneously closing the flow path between the T and A control ports 501, 502, as shown by characteristic curve 443. This enables fast and precise control of the volume flow between the T, A and P control ports 501, 502, 503. Thus, the behavior of the characteristic curves 451 with 452 and the characteristic curve 443 corresponds to the behavior of the characteristic curves 201 and 211 of the state of the art from Figures 3 and 4.

[0132] In the second case, the failsafe case, with failsafe position 25, the second control spool 41 is closed, as already described with reference to Figure 7. Therefore, there is no flow path between the T and A control ports 501, 502 via the second control edge 42, 43 (A-T2), and the characteristic curve 452 plays no role in the failsafe case. Accordingly, the volume flow is approximately zero (except for the gap leakage), see P12 in Figure 8. In failsafe position 25, the first and third control edges 45, 44 are overlapped, which is symbolically represented by the areas P13, P14 in Figures 7 and 8. Thus, in the failsafe position, a flow path from the A control port 502 to the T control port 501 is blocked during the failsafe event by covering the first control edge 45 (A-T1) sufficiently. At the same time, the third control edge 44 (PA) is also covered. This ensures that an axis, for example, of an injection unit 15, remains stationary.

[0133] Figure 9 shows an internal bore system in a control spool 400 according to the disclosure. The internal bore system enables flow between the T and A control ports 501, 502 via an axial bore 40 and forms a second control edge 42, 43 (A-T2) between the T and A control ports 501, 502. This internal bore system includes the axial bore 40, a second control spool 41 that controls flow between the A and T control ports via the second control edge 42, 43 (A-T2) in combination with the first control spool 400, and leakage relief bores 51, 52.

[0134] Figure 9 shows the control valve according to the disclosure during the failsafe case in failsafe position 25 (see Figure 8) with the failsafe valves deactivated. A first control edge 45 (A-T1 control edge) and a third control edge 44 (PA control edge) are simultaneously overlapped. Figure 9 illustrates that during the failsafe case, the A-T1 and PA control edges 45, 44 are largely overlapped. This is possible in particular because the second control spool 41 is positioned such that the flow path between the T and A control ports 501, 502 via the second control edge 42, 43 (A-T2) is blocked due to the first piston shoulder 411 of the second control spool 41. Thus, in the failsafe position, a flow path from the A control port 502 to the T control port 501 is prevented during the failsafe event by covering the A-T1 control edge 45 with sufficient coverage. At the same time, the third control edge 44 (PA) is also covered.In this way, an axis standstill, for example of an injection unit 15, can be ensured.

[0135] At the same time, the second control spool 41 in the axial bore 40 controls the A-T2 control edge 42, 43 and thus regulates a flow between the T and A control ports 501, 502. In Figure 9, the second control spool 41 is positioned such that the left piston shoulder 411 of the second control spool 41 blocks the first transverse bore 46. Thus, no exchange can take place between the T and A control ports 501, 502 via the axial bore 40 and the second control edge 42, 43 (A-T2).

[0136] In Figure 10, no failsafe event has occurred, and the control valve according to the disclosure is in normal control operation. Shown is a position of the piston shoulder of the first control spool 400, in which the third control edge 44 (PA) and the second control edge 42, 43 (A-T2) are just at the opening point to regulate the volume flow / pressure between the T and A control ports 501, 502 and the P and A control ports 503, 502. This means that in Figure 10, as already described with reference to Figure 6, the second control spool 41 is in an open position. A further movement of the first control slide 400 in the valve body 1 to the left into a positive end position results in fluid flowing from the P control port 503 via the third control edge 45 (PA) to a consumer connected to the A control port 502, for example the injection unit 15, and the pressure there increasing.An opposite movement of the first control spool 400 to the right into a negative end position causes the fluid to flow out of the consumer and thus leads to a drop in pressure, since the second control spool 41 is positioned such that the second control edge 42, 43 (A-T2) is opened by the displacement of the first control spool 400 to the right and thus a flow path is created between the T and A control connections 501, 502, this is the characteristic behavior from Figures 6 and Figure 8.

[0137] The first control spool 400 according to the disclosure thus behaves, viewed from the outside, for an observer without knowledge of the second control spool 41 and the second control edge (A-T2 control edge), as if the width of the piston shoulder 32, i.e., the length of the first control edge 45 (in the prior art), were variable. Thus, for this observer, the width of the piston shoulder 32 of the first control spool 400 is switchable even after manufacture by assuming one of the two states according to the disclosure of Figures 6 and 7. This is not possible with the control spool 4 of the prior art from Figures 1 to 5, as already explained with reference to Figures 3 to 5.

[0138] Figure 10 shows a control valve according to the disclosure in a control operation of the A-T2 and PA control edges 42, 43, 44. The second control spool 41 is in an open position with covered control edges 42, 43, i.e., the second control spool 41 is positioned such that a flow path between the T and A control ports 501, 502 via the axial bore 40 would be possible if the second control edge 42, 43 were released by displacement of the first control spool 400. This moment is shown on the characteristic curves 452 and 443 at the point P8, P11, and P9 on the x-axis of Figure 8.When the second control edge 42, 43 (A-T2) is fully opened, the maximum flow rate of the flow path via the second control edge 42, 43 (A-T2) is limited. This is why, even when the second control edge 42, 43 (A-T2) is fully opened, the flow rate is limited due to the size of the diameter of the axial bore 40 and the first transverse bore 46. From a certain stroke S of the first control spool 400 to the right, the flow path via the first control edge 45 (A-T1) is also opened. This is shown in Figure 8 by the characteristic curves 451 and 452 at points P10 and P15 on the x-axis.

[0139] Figure 11 shows a control valve according to the disclosure in a control operation of the first control edge 45 (A-T1) and control edge 23 (PB). In combination with Figure 8, in particular the characteristic curves 451 and 231, it is shown that the first control spool 400 is moved to the right in the valve body 1 to a maximum negative end position, with the third control edge 44 closed and the second control spool 41 in a closed position. This means that flow between the T and A control ports 501, 502 via the axial bore 40 is blocked. Instead, Figure 11 shows that a direct flow path is created between the T and A control ports 501, 502, in which the first control edge 45 (A-T1 control edge) is in the open position and the second control edge 42, 43 (A-T2 control edge) is closed by the second piston shoulder 412 of the second control spool 40.The corresponding volume flow signal characteristic is shown schematically in Figure 8 at the point control spool stroke S = -100% and characteristic curves 451 and 231.

[0140] Thus, in control operation with the second control spool open, the relatively small overlap between the second control edge 42, 43 (A-T2) and the third control edge 44 (PA) is realized and leads to the fast and precise controllability of the volume flow / pressure in the A control port 502, since even with a small deflection of the first control spool, a volume flow is created between the control ports TA or PA, depending on the direction of action.

[0141] At the same time, as shown in Figure 12, the first control spool 400 can be moved to the left in a positive end position with control spool stroke S = +100% according to the disclosure and thus regulate a flow between the P and A control ports 503, 502 and the B and T control ports 504, 501 via the B-side T-channel 505 via the third control edge 44 (PA) and the fifth control edge 22 (BT). There is no flow between the T and A control ports 501, 502 because the second control spool 41 in Figure 12 is positioned such that the first piston shoulder 411 keeps the second control edge (A-T2) closed and, despite the second piston shoulder 412 being in the open position, no flow occurs via the axial bore 40 between the T and A control ports 501, 502.In addition, the first control edge 45 (A-Tl) and second control edge 42, 43 (A-T2) are in an overlapped position of the first control slide 400 due to the positive end position.

[0142] In Figures 6 to 14, the piston shoulders 411, 412 of the second control spool 41 are configured according to the disclosure such that the second control spool 41 releases the flow path via the second control edge 42, 43 (A-T2) when the first control spool 400 moves to a negative end position, for example, in Figure 8. Depending on the technical requirements, the second control spool 41 can release the flow path via the second control edge 42, 43 by being moved to a positive end position (not shown in the figures).

[0143] Thus, Figures 6 to 14 show, on the one hand, how, with activated fail-safe valves 2 and 61, a zero-cut behavior and thus fast and precise controllability is possible through a relatively small overlap between the second control edge 42, 43 (A-T2) and the third control edge 44 (PA). On the other hand, with deactivated fail-safe valves, i.e., during the fail-safe event in fail-safe position 25, the leakage can be reduced to a minimum, corresponding to a gap leakage, by the first control edge 45 (A-T1) and the third control edge (PA) 44 having a sufficiently large overlap (see P12, P13, and P14 in Figure 7), thus ensuring an axis standstill of the axis connected to the disclosed control valve system 100, for example, an injection unit 15.

[0144] Figure 13 schematically shows a control valve system 100 according to the disclosure, comprising the control valve in a schematic longitudinal section and a fail-safe valve 2, a 3 / 2-way fail-safe seat valve, and a pilot valve 3. For the sake of simplicity, the valve electronics 11 and the position measuring system 10 are not shown here. The valve electronics 11 and the position measuring system 10 are schematically shown in Figures 16 to 19, where they are mounted on the right side of the valve body 1.

[0145] The valve body 1 according to the disclosure includes a first control spool 400, which can alternatively also be referred to as the main control spool 400. The first control spool 400 is provided with an axial bore 40 in which a second control spool 41 is mounted. The second control spool 41 is also referred to as the inner control spool 41. The second control spool 41 is smaller than the first control spool 400. In particular, the diameter of the second control spool 41 is smaller than the diameter of the first control spool 400, so that the second control spool 41 is housed within the axial bore 40.

[0146] The valve body 1 in Figure 13 shows, in longitudinal section from left to right, a first control port 501, a second control port 502, a third control port 503, and a fourth control port 504, as well as a B-side T-channel 505, which is connected to the first control port 501 by means of a connecting passage and / or annular channel. The first control port 501 is a T-control port 501. Thus, the B-side T-channel 505 corresponds to a B-side T-control port 501. The second control port 502 is an A-control port 502. The third control port 503 is a P-control port 503. The fourth control port 504 is a B-control port 504.

[0147] The first control spool 400 and the valve body 1 form a first control edge 45, also referred to as the A-T1 control edge. The first control edge 45 regulates the flow rate of a first flow path between the T control port 501 and the A control port 502.

[0148] In addition, the first control spool 400 and the valve body 1 form a second control edge 42, 43, which is also referred to as the A-T2 control edge. The second control edge 42, 43 regulates a flow rate via an additional flow path between the T control port 501 and the A control port 501. The second control edge 42, 43 (A-T2) and the third control edge 44 (PA) form a relatively small overlap. The first control edge 45 (A-T1) between the control ports T and A has a sufficiently large overlap. This means that in the failsafe case, only a very small volume flow flows between the control ports T and A. The volume flow is so small that it corresponds to a typical gap leakage.

[0149] The second control edge 42, 43 (A-T2) between the control ports T and A has one or more first transverse bores 46, which are connected to the axial bore 40 of the first control spool and enable flow. A puncture-shaped annular channel and / or control window 421, 431 (shown schematically in Figure 14) is formed at the inlet and outlet, respectively. This allows the second control edge (A-T2) 42, 43 to be precisely adapted to the third control edge 44 (PA control edge between the P control port 503 and the A control port 502) via the annular channel and / or the control window, depending on the application.

[0150] This ensures that the third control edge 44 (PA) can form a zero-cut overlap and the second control edge 42, 43 (A-T2) a small overlap. The sum of these two overlaps results in a relatively small overlap between the second control edge (A-T2) 42, 43 and the third control edge 44 (PA). This was also described with reference to Figures 6, 7, and 8.

[0151] In the first control spool 400, one or more additional second transverse bores 47 are provided in the area of ​​the A control connection 502, which are also connected to the axial bore 40.

[0152] The second control spool 41 activates and / or deactivates, depending on the position of an actuating piston 48, the additional flow path through the transverse bores 46, 47 and axial bore 40 between the T and A control ports 501, 502. The flow rate and the pressure via the second control edge 42, 43 (A-T2) are regulated by deflecting the first control spool 41 to the left or right.

[0153] The second control spool 41 has pressurized annular surfaces 491, 492. These are formed on both a first piston shoulder 411 in a front region of the second control spool 41 and a second piston shoulder 412 in the rear region of the second control spool 41. These are hydraulically balanced, and a load pressure via the A control port 502 cannot therefore cause the second control spool 41 to be actuated unintentionally.

[0154] Leakage entering a rear chamber 50 of the second control spool 41 is discharged via an axial relief bore 51 through the B-side T-channel 505 to the T-control port 501. For this purpose, the first control spool 400 has one or more third transverse bores 52 in the region of the B-side T-channel 505.

[0155] The second control spool 41 has a slot 53 at its right end, which faces the rear chamber 50. This slot 53 allows the leakage to be discharged, even in the blocked state, via the axial leakage relief bore 51, which is formed coaxially in extension to the axial bore 40.

[0156] Figure 14 shows a left-hand section of the control valve according to the disclosure of Figure 17, with the first and second control spools according to the disclosure as already described in Figures 6 to 13. The control valve is in active control of the third control edge 44 (PA) and second control edge 42, 43 (A-T2). The internal system is open, i.e. the second control spool 41 is positioned such that the first and second piston shoulders 411, 412 of the second control spool 41 release the passage between the T control port 501 and A control port 502 via the second control edge 42, 43 and the bore 40. In addition, the failsafe valves 2 and 61 are switched on. The actuating piston 48 is held open by the valve 61 attached to the end cap chamber 54 of the end cap 57 via the control pressure pX against a compression spring 56 which is supported internally on the end cap 57 or a stop 58 (shown in Figure 14).

[0157] The actuating piston 48 has a left annular surface 60 and a right annular surface 55. A spring chamber 59 and a left annular surface 60 of the actuating piston 48 are relieved in the failsafe case via a second valve 61, shown in the figures, for example, as a switchable 3 / 2-way failsafe seat valve, so that the compression spring 56 presses the actuating piston 48 against the second control slide 41.

[0158] The spring chamber 59 of the actuating piston 48 is continuously relieved toward the tank via the T-control port 501. To achieve this, the spring chamber 59 is connected to the T-control port 501 of the valve body 1 via one and / or more bores 62. Alternatively, it can be relieved via additional bores via a Y-relief port 507 and / or via a separate leakage relief port attached to the end cap 57 (not shown in Figure 14).

[0159] The 3 / 2-way failsafe seat valve 61 in Figure 13 is electrically switched simultaneously with the 4 / 2-way failsafe valve 2. In the failsafe condition, both failsafe valves are de-energized. In the de-energized state of the failsafe condition, the 4 / 2-way failsafe valve 2 connects the left and right control chambers 12, 13 of the first control spool 400 in the valve body 1, thus creating a hydraulic short circuit. The first control spool 400 is positioned in a defined failsafe position by a large spring 131 in the right-side control chamber 13. The compression spring 56 presses the first control spool 400, via the actuating piston 48 and the second control spool 41, into a defined failsafe position, which corresponds, for example, to the failsafe position 25 in Figure 8.

[0160] The failsafe position in the failsafe case is characterized by both the third control edge 44 (PA) and the first control edge 45 (A-T1) assuming a sufficiently large covered position. At the same time, the second control spool 41 closes the first transverse bore(s) 46, so that the second control edge 42, 43 (A-T2) is also sufficiently covered. As a result, both the first flow path between the control ports T and A and the second flow path between the control ports P and A, thus also the additional flow path between the control ports T and A, are blocked. The shaft diameter 63 of the actuating piston 48, which penetrates the axial bore 40 of the first control spool 400 and actuates the second control spool 41, has a smaller diameter than the first and second piston shoulders 411, 412 or the axial bore 40 of the second control spool 41.This allows tolerance-related axial misalignments of the piston bores to be compensated.

[0161] The second control spool 41 has a right-hand stop 64 at the rear, in the area of ​​the rear chamber 50, which serves to transfer the spring force of an internal spring 65 to the first control spool 400 in the event of a failsafe. Alternatively, this can also be achieved via a recess in the front area of ​​the second control spool 41, in the area of ​​the end cap 57 (not shown in the figures).

[0162] In normal control operation, the second control spool 41 is actively kept open via pX pressure when the actuating piston 48 is open (i.e. energized 3 / 2-way seat valve).

[0163] The actuating piston 48 is connected to the second control spool 41 via a connecting element 76 or a coupling element. The coupling element can be a threaded rod in order to compensate for manufacturing-related axial and angular misalignments between the piston axes of the second control spool 41 and the actuating piston 48. The connecting element, as a threaded rod, is designed, for example, in the form of a compensating rod with a thread on both sides (not shown in Figure 14).

[0164] For this purpose, the actuating piston 48 has an axial bore 77 into which the compensating rod is mounted. The compensating rod is secured against the small, inner control spool (41) by a right-hand lock nut 66 and against the actuating piston (48) by a left-hand lock nut 78. The lock nut 78 is hardened and also acts as a mechanical stop.

[0165] An O-ring 79 seals the right control chamber 86 of the end cap chamber 54 against the spring chamber 59 in the end cap 57. The O-ring 79 is seated in a recess 84 and is thus secured axially against displacement. The seal shown in Figure 14 can also be implemented in a different way.

[0166] The compensating rod 76 has a hexagon socket 82 at its left end, which allows for fine axial adjustment of the small, inner control spool before tightening the lock nut 78. The leakage relief bores 51, 52, 62 and the control bores for the 3 / 2-way seat valve can optionally be equipped with orifices, which are screwed into the corresponding threads.

[0167] The actuating piston 48 and the second control slide 41 are heat-treated (hardened and tempered) and thus have greater wear protection.

[0168] The overlaps and under-coverages and opening points of the control edges 42, 43, 44, 45 to each other can be increased or reduced depending on the application.

[0169] The second control slide 41 can alternatively be equipped with flow force compensating structural measures, for example grooves, cams or chamfers.

[0170] The geometry of the control edges 42, 43, 44, 45 are alternatively optimized for specific applications by means of angles, radii or control windows in order to set the corresponding flow characteristics of the T, A, P, B control connections 501, 502, 503, 504.

[0171] The end cap 57, which is attached to the left side of the valve body 1, has a thread 67 into which a hardened stop 58 is screwed to protect against wear. This prevents damage to the end cap 57 when the actuating piston 48 moves toward the end stop in an end position. Alternatively, the end cap 57 can be made entirely or partially of hardened material, or the area 68 where the actuating piston 48 comes into contact with the end cap 57 can be partially hardened.

[0172] Alternatively, the mechanism of the second control spool can be mounted on the right side of the valve body 1 in order to correspondingly configure a B-Tl and / or B-T2 control edge instead of the A-Tl and / or A-T2 control edge. Furthermore, a combination is also possible in which the second control spool 41 is extended within the first control spool 400 such that both the first and / or second control edge (A-Tl, A-T2) and, at the same time, a B-Tl and / or B-T2 control edge are configured to be switchable. The leakage relief bores 51, 52, 62 would be adapted accordingly.

[0173] In addition, the actuating piston 48 can alternatively be supplied, controlled, and actuated via a 4 / 2-way valve (not shown) or via pX pressure. If the actuating piston 48 is controlled externally via pX pressure and a 4 / 2-way seat valve, both opening and closing can be actively performed via pressure. The second control edge 42, 43 (A-T2 control edge) can be finely adjusted to the respective application in the control spool 400 via a control window (e.g., hard-milled, eroded) or alternatively via a circumferential recess (hard-turned, ground).

[0174] Figure 15 shows an alternative disclosure in which the axial leakage relief bore 51 of the first control spool 400 can open into a control slot 69 and / or a circumferential recess 70 on the fourth piston shoulder 34 of the first control spool 400, which connects the axial leakage relief bore 51 to a Y-relief port 507 of the valve body 1. For this purpose, the control slot 69 is connected to the axial leakage relief bore 51 via a fourth transverse bore 73, and a further transverse bore 74 to the Y-channel 72 is provided in the valve body 1. Thus, the leakage from the main control spool 400 can also be relieved to Y.

[0175] Alternatively, an additional compression spring can be installed in the left end cap / control chamber 54, 12 between end cap 57 and first control slide 400 (not shown in the figures).

[0176] A position measuring system or a proximity switch can be attached to the confirmation piston 48 in order to query the position of the piston and integrate it into the higher-level machine safety concept.

[0177] Alternatively, the 3 / 2-way seat valve can be supplied via the P control connection 503 of the valve body 1 instead of via the X line, if the latter is connected to the 3 / 2-way seat valve by means of bores (not shown in Figure 15).

[0178] In a further embodiment, the actuating piston can also be designed as a rotary piston. The second control spool is then designed accordingly as a rotary spool to open and close the internal system by performing a rotary movement instead of a longitudinal movement (not shown in Figure 15).

[0179] Finally, it should be noted that the description of the invention and the exemplary embodiments are fundamentally not to be understood as limiting any particular physical embodiment of the invention. All features explained and shown in connection with individual embodiments of the invention can be provided in different combinations in the subject matter according to the invention in order to simultaneously realize their advantageous effects. Figures 16 to 19 show the control valve system 100 in a schematic representation with the valve electronics 11 and a position measuring system 10 which is arranged on the right side of the valve body 1. The valve electronics and the position measuring system serve to electronically control the first control spool 400. The second control spool 41 is not electronically controlled, but is hydraulically controlled via the fail-safe valve 61 in interaction with the end cap 57 (mounted on the left side of the valve body 1) and the actuating piston 48.Figure 16 shows the control valve system 100 according to the disclosure with the fail-safe valves 2, 61 deactivated during the fail-safe event in the center position of the first control spool 400 and a second control spool 41 in the closed position. Figure 17 shows the control valve system 100 according to the disclosure with the fail-safe valves 2, 61 activated and active control of the third control edge 44 (PA) and second control edge 42, 43 (A-T2) with the second control spool 41 in the open position. However, apart from gap leaks, no volume flow flows over the second control edge 42, 43 (A-T2) or third control edge 44 (PA) since these are still just closed and are in zero overlap.Figure 18 also shows a control system 100 according to the disclosure and shows the control valve system 100 according to the disclosure with the failsafe valves 2, 61 switched on and active control in a positive maximum end position with a control spool stroke S = + 100%, in which the main control spool 400 in the valve body 1 is shifted to the left by the valve electronics 11. As a result, the third control edge 44 (PA) and the fifth control edge 22 (BT) are in an under-covered position, and a volume flow flows between the corresponding control connections. Figure 19 also shows a control system 100 according to the disclosure with the failsafe valves 2, 61 switched on and a first control spool stroke S = -100% actively brought to a negatively controlled end position. The first control edge 45 (A-Tl) is in an under-covered position and thus enables a volume flow between the T and A control connections 501, 502.The fourth control edge 22 (PB) is in the undercovered position, and a volume flow flows between the P and B control ports 503, 504. The second control spool 41 is in a closed position due to the position of its second piston shoulder 412, and thus no volume flow flows via the second control edge 42, 43 (A-T2) between the T and A control ports 501, 502.

[0180] The scope of the present invention is defined by the claims and is not limited by the features explained in the description and / or shown in the figures. List of reference symbols

[0181] 1 valve body, main stage

[0182] 2 fail-safe valve, safety valve

[0183] 3 pilot valve

[0184] 4 Control slide valves in the state of the art

[0185] 5 Control edge (state of the art)

[0186] 6 Control edge (state of the art)

[0187] 7 compression springs

[0188] 8 adjustable discs, mechanical stop

[0189] 9 control terminals X, T, A, P, B, Y

[0190] 10-way measuring system

[0191] 11 Valve electronics

[0192] 12, 13 control rooms

[0193] 14 Injection control valve, control valve in the state of the art

[0194] 15 Injection unit

[0195] 16 injection cylinders

[0196] 17 Cylinder chamber / area

[0197] 20 PA control edge

[0198] 21 AT control edge

[0199] 22 BT control edge

[0200] 23 PB control edge

[0201] 25 Failsafe position

[0202] 31 first piston shoulder

[0203] 32 second piston shoulder

[0204] 33 third piston shoulder

[0205] 34 fourth piston shoulder

[0206] 40 axial bore

[0207] 41 second control spool, inner control spool

[0208] 42, 43 second control edge, A-T2 control edge

[0209] 44 third control edge, PA control edge

[0210] 45 first control edge, A-Tl control edge

[0211] 46 at least one first cross hole

[0212] 47 at least one second cross hole

[0213] 48 actuating piston 50 rear chamber

[0214] 51 additional axial bore, leakage relief bore

[0215] 52 at least one third cross bore, leakage relief bores

[0216] 53 Slot at the right end of the second control slide

[0217] 54 End cap space

[0218] 55 right annular surface of the actuating piston

[0219] 56 compression spring

[0220] 57 End cap

[0221] 58 stop

[0222] 59 spring chamber

[0223] 60 left ring surface of the actuating piston

[0224] 61 second valve, 3 / 2-way failsafe valve

[0225] 62 one and / or more boreholes, leakage relief boreholes

[0226] 63 Collar or shaft diameter of the actuating piston

[0227] 64 right stop

[0228] 65 inner compression spring

[0229] 66 right lock nut

[0230] 67 Thread in end cap for stop

[0231] 68 area in end cap

[0232] 69 Control slot for leakage relief to the Y-channel

[0233] 70 Circumferential puncture

[0234] 72 Y-channel

[0235] 73 at least a fourth cross hole to the control slot for leakage relief to the Y-channel

[0236] 74 additional cross holes

[0237] 76 connecting element

[0238] 77 axial bore

[0239] 78 left lock nut

[0240] 79 O-ring

[0241] 80 Connection between the two T control connections, tank bridge

[0242] 82 hexagon socket

[0243] 84 undercut

[0244] 86 right control chamber of the end cap chamber 100 control valve system according to the disclosure

[0245] 131 large spring in the right-hand control room

[0246] 201 Volume flow signal characteristic of the PA control edge

[0247] 211 Volume flow signal characteristic of the AT control edge

[0248] 221 Volume flow signal characteristic of the BT control edge

[0249] 231 Volume flow signal characteristic of the PB control edge

[0250] 411 first piston shoulder of the second control spool

[0251] 412 second piston shoulder of the second control slide

[0252] 400 first control slide

[0253] 421, 431 puncture-shaped ring channel, control window

[0254] 443 Volume flow signal characteristic curve third control edge, PA control edge

[0255] 451 Volume flow signal characteristic first control edge, A-Tl control edge

[0256] 452 Volume flow signal characteristic second control edge, A-T2 control edge

[0257] 491 (Annular) surface on the left piston shoulder of the second control slide

[0258] 492 (Annular) surface on the right piston shoulder of the second control slide

[0259] 501 T-control connection, first control connection

[0260] 502 Control port A, second control port

[0261] 503 Control terminal P, third control terminal

[0262] 504 Control port B, fourth control port

[0263] 505 B-side T-channel

[0264] 506 Control connection X

[0265] 507 Relief connection Y

Claims

Patent claims 1. Control valve with switchable control edge, comprising: a valve body (1) with a first control slide (400) and at least one first and second control connection (501; 502; 503; 504; 505) and at least one control edge (6; 44; 45), wherein the first control slide (400) has an axial bore (40) and a second control slide (41) is formed in the axial bore (40); an end cap (57) with actuating piston (48), wherein the Actuating piston (48) is designed to engage in the axial bore (40), and the actuating piston (48) is designed to displace the second control slide (41) in the axial bore (40).

2. Control valve according to claim 1, wherein a connecting element (76) is formed between the actuating piston (48) and the second control slide (41) in order to compensate for axial and angular offsets.

3. Control valve according to claim 1, wherein the valve body (1) and the first control slide (400) have a first control edge (45) and a second control edge (42, 43); wherein a relatively small overlap is formed between the second control edge (42, 43) and a third control edge (44) and the first control edge (45) has a large overlap.

4. Control valve according to one of the preceding claims, wherein the second control edge (42, 43) has a puncture-shaped annular channel (421, 431) or at least one control window (421, 431).

5. Control valve according to one of the preceding claims, wherein the second control edge (A-T2; 42, 43) has at least one first transverse bore (46) is connected to the axial bore (40) in the first control slide (400).

6. Control valve according to one of the preceding claims, wherein the first control slide (400) forms at least one second transverse bore (47) in the connection region of a second control connection (502), in particular an A control connection, of the valve body (1), wherein the at least one second transverse bore (47) is connected to the axial bore (40).

7. Control valve according to one of the preceding claims, wherein the actuating piston (48) is designed to control a flow path via the second control edge (A-T2; 42, 43) by means of the second control slide (41).

8. Control valve according to one of the preceding claims, wherein the second control slide (41) has two surfaces (491; 492) with equal areas for hydraulic compensation.

9. Control valve according to one of the preceding claims, wherein the axial bore (40) of the first control slide (400) comprises a chamber (50) with an internal compression spring (65).

10. Control valve according to one of the preceding claims, wherein an axial relief bore (51) is formed coaxially with the axial bore (40), and wherein in particular the first control slide (400) has in the region of a B-side T-channel (505) at least one third transverse bore (52) which is connected to the axial relief bore (51) and forms a leakage flow path.

11. Control valve according to one of the preceding claims, wherein the second control slide (41) forms a slot (53) on its right end face for diverting a leakage.

12. Control valve according to one of the preceding claims, wherein the end cap (57) further comprises: a valve (61); and a spring chamber (59) with a compression spring (56) and a stop (58).

13. Control valve according to one of the preceding claims, wherein the spring chamber (59) is connected to the valve body (1) via a relief bore (62).

14. Use of the control valve according to one of the preceding claims as an injection control valve for controlling an injection unit (15), in particular an injection molding machine.

15. Control valve system (100), comprising - a pilot valve (3); a fail-safe valve (2), and - control valve according to one of the preceding claims.

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