WO1997030304A1

WO1997030304A1 - Valve unit

Info

Publication number: WO1997030304A1
Application number: PCT/EP1997/000401
Authority: WO
Inventors: Alfred Kostorz
Original assignee: Mannesmann Rexroth Ag
Priority date: 1996-02-15
Filing date: 1997-01-30
Publication date: 1997-08-21
Also published as: DE19605557A1

Abstract

The valve unit proposed has a housing (10) and at least one pump connection point (P), a reservoir connection point (T) and a consumer connection point (A) plus a pressure limiting valve (20) and a control valve (18) incorporated in the same assembly, the two valves (18, 20) being connected in parallel to each other between the pump connection point (P) and the reservoir connection point (T). The valve unit proposed enables hydraulic circuits for the protection of hydraulic pumps and/or for the balanced starting of a hydraulic pump, as well as for the reduction of the pressure at a hydraulic consumer, to be designed to fit in a very small space. In the event of damage, the valve unit can be rapidly replaced by a new one, thus avoiding long consumer down times.

Description

Valve cartridge

The invention relates to a valve cartridge with a housing part. According to the invention, the valve cartridge has at least one pump connection, a tank connection and a consumer connection, as well as a pressure limiting valve and a switching valve in one structural unit, the two valves being connected in parallel to one another between the pump and tank connections.

The relevant components are known in the prior art as self-contained individual components with which hydraulic circuits can be realized, which serve, for example, as pump protection and for relieving starting of a hydraulic pump or for lowering the pressure on a hydraulic consumer. On the basis of this prior art, the object of the invention is to create a valve cartridge with which hydraulic circuits can be implemented, which can be produced cost-effectively and require only a small installation space. A corresponding object is achieved by a valve cartridge with the features of claim 1.

With the valve cartridge according to the invention, the hydraulic circuits mentioned can be implemented in the smallest possible installation space and the valve cartridge can be easily replaced as a structural unit in the event of a possible damage, without a hydraulic actuating device possibly connected to the respective consumer connection being subject to longer downtimes experiences.

In a preferred embodiment of the valve cartridge according to the invention, a check valve is arranged inside the housing part, which, facing the consumer connection, blocks the fluid backflow from the consumer connection in the direction of the pump connection in order to relieve the pump connection.

In a further preferred embodiment of the valve cartridge according to the invention, the switching valve is a 2/2-way valve which can be brought into its opening position which establishes the fluid-carrying connection between the pump and the tank connection by means of an actuating magnet. The actuating or switching magnets in question can be controlled electrically and the actuating rod of the actuating magnet, which can be moved and moved longitudinally, interacts with the respective valve member of a switching valve, for example in the form of a 2/2-way valve. Since the actuating magnet mentioned is also available in a compact design, it can be flanged to the valve cartridge and together with it form a sales and actuation unit. Further advantageous feature configurations are the subject of the subclaims.

The valve cartridge according to the invention is explained in more detail below with reference to the drawing.

In principle, they show the

1 shows a longitudinal section through a first embodiment of the

Valve cartridge;

2 shows a longitudinal section through a modified embodiment of the valve cartridge according to FIG. 1, insofar as these changes are concerned;

3 and 4 basic hydraulic circuits which are realized with a valve cartridge according to FIGS. 1 and 2.

The valve cartridge shown in FIG. 1 has a housing part 10 which is provided with a pump connection P, a tank connection T and a consumer connection A. Along its cylindrical outer circumference, the housing part 10 tapers step-wise in cross-section towards the consumer connection A, an external thread 12 being arranged in the middle step region, with which the valve cartridge or the like can be fixed into a fixed part of a hydraulic actuation device. can be screwed in. The pump connection P and the tank connection T are arranged essentially transversely and the consumer connection A is arranged parallel to the longitudinal axis 14 of the valve cartridge. Inside the housing part 10 there is a check valve 16 at the end facing the consumer connection A and a switching valve 18 in the form of a 2/2-way valve at the other end of the valve cartridge. Between the check valve til 1 6 and the switching valve 1 8, a pressure relief valve 20 is added to the housing part 1 0. All of the connections and valves mentioned are accommodated in the one-piece housing part 1 0 and therefore form the valve cartridge as a unit according to its basic function. The housing part 10 can also be of interrupted multi-part construction in the longitudinal direction of the valve cartridge; however, preferably consists of a self-contained housing unit.

The valves mentioned are arranged one behind the other in a central central bore 22 of the housing part 10, which will be discussed in more detail below. The switching valve 1 8 in the form of the 2/2-way valve can be brought into its opening position which establishes the fluid-carrying connection between pumps P and tank connection T by means of an actuating magnet 24. Of the actuating magnet 24 mentioned, which is known in the prior art, because of the simpler representation, as viewed in the direction of view of FIG. 1, only the shift rod 26 and the sleeve-like magnetic tube 28 are shown on the left, which are provided with an external thread in an internal thread a screw-in part 30 can be screwed in, which in turn is provided with an external thread and is longitudinally adjustable in the inner part of the housing part 10, the set position of the screw-in part 30 being retained via a lock nut 32.

A valve guide member 36 of the switching valve 1 8 is screwed into the central bore 20 and in partial face-to-face contact with the magnetic tube 28. Along its inner circumference, the switching member 38 of the switching valve 18 is guided in the valve guide member 36 in a longitudinally displaceable manner, which is spring-loaded via the compression spring 40 in the direction of its closed position blocking the pumps P- from the tank connection T, as shown in FIG Fig. 1. In order to rule out inhibitions in the movement sequence of the switching element 38 due to existing pressure differences within the valve cartridge, this is penetrated over its entire length by a pressure compensation channel 42, which is provided at its end facing the switching rod 26 with cross bores opening into the central bore 22. Furthermore, the compression spring 40 engages with one free end on the end face of the fixed valve guide member 36 and with its other end on a widening 44 which is fixedly connected to the switching element 38. On its side facing the consumer connection A, the switching element 38 has a closed outer groove on the outer circumference, which favors the flow of current, which in its position shown in FIG. 1 opens into continuous transverse bores 48 of the valve guide element 36. The opposite end of the switching element 38 is in direct contact with the free end of the switching rod 26 of the actuating magnet 24, via which the switching element 38 can be actuated.

The valve tappet 50 of the pressure limiting valve 20 is in turn guided longitudinally directly in the central bore 22, the closing head 52 of the valve tappet 50 being spherical at least at its end remote from the consumer connection A and cooperating with a contact plate 54 which acts on the Place of the system with the closing head 52 has a conically tapering centering surface, so that when the valve plunger 50 is actuated, it can be moved back centered into its closed position shown in FIG. The free end face of the contact plate 54 cooperates with a compression spring 56, which is supported with its one free end on the contact plate 54 and with its other end on a front recess 58 at the end of the screw-in part facing the consumer connection A. 30, which for this purpose engages with a stepped extension 60 in the central bore 22 of the housing part 10. This peg-like extension 60 has a central channel 62, which constantly de Establishes connection between the switching element 38 of the switching valve 1 8 and the tank connection T.

To set the spring preload of the compression spring 56, the screw-in position of the screw-in part 30 can be changed, an adjusted closing force value of the pressure spring 56 being able to be maintained via the lock nut 32, which permanently fixes the screw-in part 30 in its position in the housing part 10. Due to the compression spring 56, the valve tappet 50 of the pressure-limiting valve 20 is held in the direction of its closed position, which separates the pumps P- from the tank connection T and is shown in FIG. While the pressure of the tank connection T, which usually corresponds to the ambient pressure, acts together with the compression spring 56 on the closing head 52 of the valve tappet 50, the pump pressure P on the opposite side acts on a taper 64 of the valve tappet 50 via the pump connection P. , which is arranged between the closing head 52 and a guide end piece 66 of the valve tappet 50, which is flush with the consumer connection A adjacent in the tapered central bore 22 of the housing part 10.

The closing ball 68 of the check valve 16 is received by a closing part 70, which holds the closing ball 68 spring-loaded in its closed position shown in FIG. 1, the compression spring 72 provided for this purpose being supported with one free end on the closing part 70 and with the other End on an end plate 74 which is provided with the longitudinal bores 76 forming the consumer connection A. In the open position of the check valve 16, the closing ball 68 together with the closing part 70 in the illustration according to FIG. 1 releases the fluid-carrying path between the pump connection P and the consumer connection A. Between the check valve 1 6 and the pressure relief valve 20, a fluid-blocking closure 78 is inserted into the central bore 22 of the housing part 10 and into the A fluid-conducting connection in the form of the central channel 62 can have an orifice 80 inserted between the pressure-limiting valve 20 and the switching valve 18 as an additional option.

In the closed position shown in FIG. 1, the check valve 1 6 also interrupts the fluid-carrying connection between the pump connection P and a connecting line 82 leading to the switching valve 18. This connecting line 82, which runs slightly obliquely in the housing part 10, opens with its one free end into the valve chamber 84 of the Check valves 16 and with their other free end in a fluid space 86 which is delimited on the outer circumferential side by the housing part 10 and on the inner circumferential side by the peg-like extension 60 and in turn on the end side by the housing part 10 and the screw-in part 30. In continuation of this fluid-carrying connection to the switching valve 18, longitudinal bores 88 are arranged in the screw-in part 30, which end at one end in the fluid chamber 86 and at the other end into the transverse bores 48 of the valve guide member 36.

The hydraulic circuit shown in FIG. 3, insofar as it is surrounded by dash-dotted lines, is implemented as a whole by the valve cartridge shown in FIG. If pressure is applied to the pump connection P via the hydraulic pump 90 according to FIG. 3, the check valve 1 6 opens and establishes a fluid-carrying connection to the consumer connection A. Furthermore, the pressure prevailing in the pump connection P is both at the switching valve! 1 8 as well as on the pressure relief valve 20. If the closing pressure at the pressure limiting valve 20, which can be set via the compression spring 22, is exceeded by the pressure present in the pump connection P, the pressure limiting valve 20 serving as protection opens and the fluid quantity is conveyed in the direction of the tank connection T and then to the tank T. This fluid-carrying connection is also established when, after actuation of the actuating magnet 24, the switching valve 18 assumes its fluid-continuous opening position, the switching rod 26 displacing the switching element 38 from its closed position shown in FIG. 1 to the right in the direction of view of FIG and thereby releases the fluid-carrying connection between the pump connection P, the connecting line 82, the fluid space 86, the longitudinal and transverse bores 88 and 48 to the central channel 62 and the subsequent central bore 22 and the tank connection T. With the hydraulic circuit realized by the valve cartridge, the hydraulic pump 90 is secured and the pressure present at a hydraulic consumer which is connected to the consumer connection A can be reduced accordingly. The check valve 16 is, as shown in FIG. 3, hydraulically connected between the connections of the switching valve 18 and the pressure limiting valve 20 on the pump side.

In the following, a modified embodiment of the valve cartridge according to the invention is explained in more detail with reference to FIGS. 2 and 4, the components which have the same function as those in the arrangement described above being provided with the same reference numerals, so that the above-described also applies to that the following embodiment applies. Furthermore, for the sake of simplicity, FIG. 2 shows only the front part of the modified valve cartridge facing the consumer connection A. Seen in the direction of FIG. 2, those valve components would then follow on the left side of the figure, as are shown in FIG. 1. The modified embodiment is therefore only described in the following insofar as it differs substantially from the previous embodiment.

The main difference is a change in the arrangement of the check valve 1 6, which is now as shown in Figure 2 is held in the closed valve position 84 via the compression spring 72 in a closed position such that there is a permanent fluid-conducting connection from the pump connection P to the connecting line 82 in both directions. The corresponding change, in which the check valve 16 is arranged facing the consumer connection A in the fluid direction behind the branch with the switching valve 18, is also reflected in the corresponding hydraulic circuit according to FIG. 4, whereby again the dash-dotted framed hydraulic components are realized in a structural unit in the valve cartridge according to FIG. The relevant circuit function also serves to protect the pump and to relieve the start of the hydraulic pump 90. If an aperture 80 is provided in the hydraulic circuits according to FIGS. 3 and 4 and therefore also in the respective valve cartridge to the tank side between the switching valve 18 and the pressure relief valve 20 is switched, this would delay the associated fluid flow when the switching valve 18 is actuated, for example to delay the hydraulic lowering of a press ram or the like, provided that a hydraulic actuating device is connected to the consumer port A.

As shown in FIG. 2 in particular, the pump connection P and the tank connection T can be divided into a plurality of transverse branches 94 via longitudinal grooves 92 arranged on the outer circumference of the housing part 10. The check valve 16, which represents an additional safeguard, can also be completely dispensed with in the valve cartridges shown, the respective connecting line 82 then having to be permanently connected to the pump connection P.

Claims

Patent claims

1 . Valve cartridge with a housing part (1 0), which has at least one pump connection (P), a tank connection (T) and a consumer connection (A) as well as a pressure relief valve (20) and a switching valve (1 8) in one unit, the two valves (1 8, 20) are connected in parallel to one another between the pump (P) and tank connection (T).

2. Valve cartridge according to claim 1, characterized in that within the housing part (10) a check valve (1 6) is arranged, the consumer connection (A) facing the fluid backflow from the consumer port (A) in the direction of the pump port (P) blocks .

3. Valve cartridge according to claim 1 or 2, characterized in that the switching valve (1 8) is a 2/2 way valve which by means of an actuating magnet (24) in its, the fluid-carrying connection between pumps (P) - and tank connection (T) producing opening position can be brought.

4. Valve cartridge according to one of claims 1 to 3, characterized gekennzeich¬ net that the valve tappet (50) of the pressure relief valve (20) is spring-loaded in the direction of its the pumps (P) - from the tank connection (T) separating the closed position is held and that the pressures present at these two connections (P, T) act on both sides of the valve tappet (50).

5. Valve cartridge according to one of claims 1 to 4, characterized gekennzeich¬ net that the switching element (38) of the switching valve (18) spring-loaded in Rieh- tion of the pump (P) - from the tank port (T) blocking position and that the pressures at these two ports (P, T) act on both sides of the switching element (38).

6. Ventilpatroπe according to claim 5, characterized in that the Schalt¬ member (38) longitudinally and from the switching rod (26) of the actuating magnet (24) in its the pumps (P) - with the tank connection (T) ver¬ binding Openable position is guided in a screw-in part (30) which can be advanced lengthways within the housing part (10) and via which the spring (56) of the pressure-limiting valve (20) can be adjusted.

7. Ventiipatrone according to any one of claims 2 to 6, characterized gekennzeich¬ net that the closing ball (68) of the check valve (1 6) by a spring-loaded closing part (70) held in its closed position, the connecting line (82) leading to the switching valve (1 8) ) shut off from the pump connection (P) or continuously releases it.

8. Valve cartridge according to one of claims 2 to 7, characterized gekennzeich¬ net that along a common central axis (14) of the housing part (10) in a row, starting with the consumer connection (A), the check valve (16), the pressure relief valve (20 ) and the switching valve (18) follow and that all valves (16, 18, 20) are received in a central bore (22) of the housing part (10).

9. Valve cartridge according to claim 8, characterized in that between the check valve (16) and pressure relief valve (20) in the Mittenboh¬ tion (22) a closure (78) is inserted and that in the fluid-carrying connection (62) between the pressure relief valve (20) and switching valve (1 8) an orifice (80) or throttle is used.

10. Valve cartridge according to one of claims 1 to 9, characterized gekennzeich¬ net that to the consumer connection (A) the housing part (10) gradually decreases in diameter and that at least one housing stage is provided with an external thread (12).