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EP-4739923-A1 - PISTON-INTEGRATED OVERFLOW VALVE

EP4739923A1EP 4739923 A1EP4739923 A1EP 4739923A1EP-4739923-A1

Abstract

The invention relates to a piston-integrated overflow valve located in a piston (50) of a working cylinder, comprising a first valve plunger (10) and a first actuating tappet (14), a second valve plunger (20) and a second actuating tappet (24), a spring element (30), a valve chamber (40) and an end bush (70). The valve plungers (10, 20) are axially slidable in the valve chamber (40) and each provide a closed position in a distal end position and an open position in a proximally axially offset working position. The valve chamber (40) has a hollow-cylindrical basic shape formed by an inner lateral surface of an axial bore (60) in the piston (50), wherein an end bush (70) is located in the axial bore (60) at at least one axial bore end (61) and is welded to the piston (50) along an outer bush ring face (72) by means of a circumferential laser ring weld (73), the circumferential laser ring weld (73) forming a pressure-medium-tight sealing plane.

Inventors

  • BUETER, JOSEF

Assignees

  • Bümach Engineering International B.V.

Dates

Publication Date
20260513
Application Date
20240604

Claims (7)

  1. 1 . Piston-integrated overflow valve, arranged in a piston (50) of a working cylinder, having a first valve piston (10) and a first actuating tappet (14), a second valve piston (20) and a second actuating tappet (24), a spring element (30) and a valve chamber (40) as well as a closure bushing (70), wherein the first valve piston (10) is arranged axially displaceably in the valve chamber (40) and provides a closed position in a distal end position and an open position in a proximally axially offset working position and has the first distal axial valve piston surface (11) on the tappet side, which together with a first axial chamber ring surface (43) forms a first valve sealing plane (12a) in the closed position and a first axial valve opening gap (12b) in the open position, wherein the first actuating tappet (14) is assigned to the first valve piston (10), a first tappet foot (15) and a first Tappet head (16) with a shaped section for a positive distal axial position determination of the first actuating tappet (14) and is arranged axially displaceably in a first tappet bore (13) and is designed for a rest position and for an actuating position, wherein in the rest position the first tappet foot (15) leads distally out of the first tappet bore (13) and in the actuating position the first tappet foot (15) is designed for a pressure contact with a first stop surface and the first actuating tappet is axially proximally displaced and the first tappet head (16) is designed for a pressure contact with the first distal axial valve piston surface (11) for an axial position change of the first valve piston (10) from the distal end position to the working position, wherein the second valve piston (20) is arranged axially opposite the first valve piston (10) and displaceably in the valve chamber (40) and provides a closed position in a distal end position and an open position in a proximal axially offset working position and has the second distal axial valve piston surface (21) on the tappet side, which together with a second axial chamber ring surface (44) forms a second valve sealing plane (22a) in the closed position and a second axial valve opening gap (22b) in the open position, wherein the second actuating tappet (24) is assigned to the second valve piston (20), has a second tappet foot (25) and a second tappet head (26) with a mold section for a positive distal axial position determination of the second actuating tappet (24) and is arranged axially displaceably in a second tappet bore (23) and is designed for a rest position and for an actuated position, wherein in the rest position of the second tappet foot (25) extends distally out of the second tappet bore (23) and in the actuating position the second tappet foot (25) is designed for pressure contact with a second stop surface and the second actuating tappet is displaced axially proximally and the second tappet head (26) is designed for pressure contact with the second distal axial valve piston surface (21) for an axial change in position of the second valve piston (20) from the distal end position into the working position, wherein the spring element (30) applies an axial force to the valve pistons (10, 20) in the direction of the closed position, wherein the valve chamber (40) has a hollow cylindrical basic shape and has a chamber jacket surface (45) and a first and a second axial boundary surface (41, 42), wherein the chamber jacket surface (45) is formed by an inner jacket surface of an axial bore (60) in the piston (50), wherein a closure bushing (70) is arranged in the axial bore (60) at at least one axial bore end (61), wherein the closure bushing (70) has a bushing bore (74) which forms the first tappet bore (13), and wherein an inner bushing ring surface (71) of the closure bushing (70) forms the first axial boundary surface (41) and the first axial chamber ring surface (43) is arranged on the inner bushing ring surface (71), and wherein the closure bushing (70) is welded to the piston (50) along an outer bushing ring surface (72) by means of a circumferential laser ring weld seam (73), and wherein the circumferential laser ring weld seam (73) forms a pressure medium-tight sealing plane, and wherein the piston-integrated overflow valve is designed for a closure operating state, a first and a second overflow operating state, wherein in the closure operating state the valve pistons (10, 20) are arranged in the closed position, wherein in the first overflow operating state in a first end position of the piston (50) the first tappet foot (15) is in pressure contact with the first stop surface, the first actuating tappet (14) has the actuating position and the first valve piston (10) has the working position, the second actuating tappet (24) has the rest position and the second valve piston (20) also has the working position by means of a pressure medium pressure acting on the second axial chamber ring surface (44), wherein an overflow channel for the pressure medium is opened through the second tappet bore (23), through the second axial valve opening gap (22b), through the valve chamber (40), through the first axial valve opening gap (12b) and through the first tappet bore (13), wherein in the second overflow operating state in a second end position of the piston (50) the second tappet foot (25) is in pressure contact with the second stop surface, the second actuating plunger (24) is the Actuating position and the second valve piston (20) is in the working position, the first actuating tappet (14) is in the rest position and the second valve piston (20) is also in the working position by means of a pressure medium pressure acting on the first axial chamber ring surface (43), wherein an overflow channel for the pressure medium is opened through the first tappet bore (13), through the first axial valve opening gap (12b), through the valve chamber (40), through the first axial valve opening gap (22b) and through the second tappet bore (23).
  2. 2. Piston-integrated overflow valve according to claim 1, characterized in that the end bushing (70) has a ring-shaped bushing head (75) and the axial bore (60) at the axial bore end (61) has an axial bore widening (63) corresponding to the bushing head (75).
  3. 3. Piston-integrated overflow valve according to one of the preceding claims, characterized in that the end bushing (70) has an outer O-ring (76) which rests on the inner wall of the axial bore (60).
  4. 4. Piston-integrated overflow valve according to one of claims 1 to 3, characterized in that the axial bore (60) has, axially opposite the end bushing (70), at a further axial bore end (62), a closing section (80) with a closing section bore (82) which forms the second tappet bore (23), that an inner shoulder ring surface (81) of the closing section (80) forms the second axial boundary surface (42), and that the second axial chamber ring surface (44) is arranged on the inner shoulder ring surface (81).
  5. 5. Piston-integrated overflow valve according to one of claims 1 to 3, characterized in that the end bushing (70) has a further end bushing (90) at a further axial bore end (62) opposite the end bushing (70), that the further end bushing (90) has a further bushing bore (94) which forms the second tappet bore (23), that a further inner bushing ring surface (91) of the further end bushing (90) forms the second axial boundary surface (42), that the second axial chamber ring surface (44) is arranged on the further inner bushing ring surface (91) of the further end bushing (90), and that the further end bushing (90) is welded to the piston (50) along a further outer bushing ring surface (92) by means of a further circumferential laser ring weld seam (93), and that the further circumferential laser ring weld seam (93) has a further forms a pressure-tight sealing layer.
  6. 6. Piston-integrated overflow valve according to one of the preceding claims, characterized in that an elastomeric seal is assigned to the first or the second valve sealing plane (12a, 12b).
  7. 7. Piston-integrated overflow valve according to one of the preceding claims, characterized in that the spring element (30) is designed as an elastomeric component. SIX PAGES OF DRAWINGS

Description

piston-integrated overflow valve The invention relates to a double-acting overflow valve in a piston unit of a working cylinder, particularly designed for use in a master-slave working cylinder arrangement. Overflow valves as such are known from the prior art. They are designed to control pressure medium flows between adjacent working chambers of hydraulic devices, in particular between working chambers of a working cylinder separated by a piston. For example, valves are known which have a movable element in an interior space to which an external force is applied, whereby a flow between the inlet and outlet can be controlled due to pressure. Such mechanically controlled valves can be used in working cylinders for pressure equalization between adjacent working chambers of a working cylinder or for supplying pressure medium to pressure accumulators in order to compensate for pressure losses and leakage current losses that occur during operation. In this regard, the publication DE 20 2004 011 532 U1 describes a valve in whose valve chamber a pre-stressed elastic molded body is arranged as a blocking element. To exert an axial force on the blocking element, a tappet that can be mechanically operated from the outside is provided on at least one side of the valve. This is a structurally simple and cost-effective solution, although the blocking body made of an elastomer must withstand high mechanical loads if the valve is used over a long period of time. confirmation copy Furthermore, the publication DE 10 2004 044 832 B3 discloses a backflow preventer which has an inlet opening, an outlet opening and a leakage opening arranged between them. In addition, two check valves and a movable valve body are present. By means of a bypass channel which bypasses the two check valves, an excess pressure present in the outlet opening is at least partially transferred to the area of the inlet opening. Another solution for a double-acting overflow valve is shown in the document DE 3 610 160 B1. This discloses a solution in which the overflow behavior can be adjusted separately according to pressure or volume, depending on the overflow direction. The state of the art shown shows overflow valves that make an important contribution to solving the technical problem of pressure or volume equalization. These are technically sophisticated approaches that are correspondingly complex to implement. The object of the invention is therefore to provide a double-acting overflow valve of a working cylinder, which enables a pressure-dependent control of the flow rate of the fluid, which ensures a permanent and reliable sealing of the inlet and outlet and which is particularly cost-effective and structurally simple to manufacture. The problem is solved by the features listed in patent claim 1. Preferred further training courses arise from the subclaims. The overflow valve according to the invention is based on the basic principle of a double-acting valve. For this purpose, the overflow valve according to the invention has two spring-loaded opposing valve pistons, each with an associated actuating tappet, which are arranged in the piston of a working cylinder and are actuated depending on the position of the piston. The opening of the valve on the non-pressurized side, hereinafter also referred to as the pressure-free side, is caused in one of the piston's end positions by a frontal stop of the tappet on the relevant closure part of the pressure-free working chamber of the working cylinder. At the same time, the valve piston on the pressurized side is lifted out of its closed position due to pressure, which releases an overflow of pressure medium from the pressurized working chamber through the now opened pressure medium channel along the two valve pistons in the open position. In the opposite end position of the piston, this applies accordingly for an overflow in the opposite direction. In all positions other than the end positions, the overflow valve is closed in both directions and the working chambers separated by the piston are reliably pressure-tight. With the present invention, a solution was surprisingly found with which such an overflow valve can be provided in a particularly cost-effective, reliable and tamper-proof manner. The piston-integrated overflow valve according to the invention enables these advantages according to the structure and mode of operation described below. According to the invention, the piston-integrated overflow valve is arranged in the piston of a working cylinder and connects the working spaces of the working cylinder separated by the piston. For this purpose, the overflow valve is preferably arranged essentially axially parallel to the main longitudinal axis of the working cylinder. As basic components, it has a first valve piston with an associated first actuating tappet and a second valve piston with an associated second actuating tappet as well as a spring element and a valve chamber. Both valve pistons ar