Coupling element for a hydraulic coupling

Abstract

Coupling element, in particular coupling sleeve (1), for a hydraulic coupling on a pressure medium line, with a housing (2, 7) and a sealing unit (3, 8), wherein the housing (2, 7) has a flow channel (28, 75) for a pressure medium and a coupling axis (A), and wherein the sealing unit (3) comprises a valve tappet (31) with a valve piston (32) which is held in a tappet guide (4) which is connected to the housing (2), wherein the valve tappet (31) has at least one groove (34) with a first groove flank (341) facing the valve piston (32) and a second groove flank (342) opposite said first groove flank and facing away from the valve piston (32), into which groove the tappet guide (4) engages, whereby the tappet guide (4) and the valve tappet (31) are connected in a form-fitting manner, characterized in that the The second groove flank (342) of the at least one groove (34) facing away from the valve tappet (31) is designed to widen conically outwards.

Description

[0001] The invention relates to a coupling element, in particular a coupling sleeve for a hydraulic coupling on a pressure medium line according to the preamble of claim 1.

[0002] Hydraulic couplings consist of a coupling sleeve and a coupling plug that can be connected to it. They are used to connect two sections of a pressure medium line, via which hydraulically operated devices, such as tools or attachments, are connected to a hydraulic source, such as an agricultural or construction machine. Generally, a hydraulic coupling is used to transfer flow energy from a machine to a work device. This creates high static and dynamic loads.

[0003] The amount of flow energy depends on pressure and flow rate. Since high flow rates always lead to power losses due to friction, it is better for system efficiency to transmit high power through high pressures at lower flow rates. Against this background, the pressure resistance of a fluid coupling is crucial.

[0004] Since fluid couplings are also used in bypasses, i.e., in a branch of a pipeline, they can be subjected to dynamic pressure loads even when uncoupled. Consequently, the couplings must exhibit high pressure resistance in both the coupled and uncoupled states.

[0005] So-called flat-sealing coupling sleeves and coupling plugs are known from the prior art. These are characterized by the fact that, when not connected (uncoupled), the components of the coupling plug or coupling sleeve form a flat and closed surface in the connection interface area. This prevents the ingress of dirt into the housing and between the components, as well as reliably preventing the loss of pressure fluid.

[0006] Coupling a hydraulic coupling, i.e., establishing a positive connection between a coupling sleeve and a coupling plug, is usually done by inserting the coupling plug into a coupling sleeve. The force applied during insertion opens a valve to fluidically connect the flow channel of the coupling plug with the flow channel of the coupling sleeve. At the same time, this creates a positive connection between the coupling plug and coupling sleeve to stabilize the connection or the engaged state. In the uncoupled state, the flow channels of the coupling sleeve and coupling plug are sealed from the environment.

[0007] In Fig. 1 is a coupling sleeve known in the prior art, in Fig. 2 schematically shows a coupling plug known in the prior art. One of the coupling elements, in this case the coupling sleeve, has a stationary tappet and a movable valve sleeve. In the closed state, the valve sleeve is sealed against the tappet and against the fluid-carrying flow channel of the coupling half. In the coupled state, the valve sleeve is sealed against the flow channels of both coupling elements. The stationary tappet is held in a tappet guide comprising at least two holding elements. The other of the coupling elements, in this case the coupling plug, has a movable valve tappet, which is sealed against the flow channel in the closed state.

[0008] The flow channels of both coupling halves are delimited at their ends facing away from the respective valve stems by a connecting piece to which a fluid line can be connected. The two coupling elements are connected via a screw sleeve that is rotatably mounted on one coupling element and can be screwed onto a thread of the second coupling element. Alternatively, one coupling element has an axially movable sleeve and radially movable locking elements, such as balls. The other coupling element has a circumferential groove on the outside, into which the locking elements engage when coupled.

[0009] To ensure the required high pressure resistance, the connections between individual components must be highly reliable. The stationary valve tappet positioned in the flow channel is particularly subject to the dynamic pressures of the pressure medium, which places high demands on the connection between the tappet guide and the valve tappet.

[0010] In Fig. Figure 1 shows such a connection, which has long been common in the prior art. However, it has been shown that a significant proportion of cases in which a hydraulic coupling fails are due to a failure of this connection.

[0011] The invention aims to remedy this situation. The invention is based on the object of providing a coupling element, in particular a coupling sleeve for a hydraulic coupling on a pressure medium line, whose pressure resistance is increased. According to the invention, this object is achieved by a coupling element having the features of claim 1.

[0012] The invention provides a coupling element for a hydraulic coupling on a pressure medium line, the pressure resistance of which is increased. Because the second groove flank of the at least one groove, facing away from the valve piston of the valve tappet, is designed to widen conically outwards, stresses that can arise from notch effects in the groove and that can lead to breakage at higher pressures or even dynamic loads are reduced. The conical support increases the contact surface of the tappet on the holding elements and improves the flow of force in the tappet. The maximum stress in the holding elements can also be reduced in this way. The tappet guide is preferably formed from at least two holding elements. Advantageously, exactly one circumferential groove that widens conically outwards is arranged to accommodate the at least two holding elements.

[0013] In a further development of the invention, the second groove flank of the at least one groove has a cone angle of between 50° and 140°, particularly preferably between 60° and 130°, in particular between 70° and 120°. The cone angle is the angle of an imaginary cone on which the second groove flank of the at least one groove lies. It has been shown that advantageous stress distributions can be achieved by such an inclination of the second groove flank.

[0014] In an embodiment of the invention, the first groove flank of the at least one groove, opposite the second groove flank, extends orthogonally to the coupling axis. This ensures a good fixation of the retaining elements of the tappet guide to the valve tappet.

[0015] In a further embodiment of the invention, the housing (2, 7) is formed from a base body and at least one sleeve body connected to it in a form-fitting and / or force-fitting manner, wherein the base body and a sleeve body of the at least one sleeve body delimit an annular channel with a preferably rectangular cross-section, in which a sealing ring, preferably an O-ring, is arranged to seal a sealing gap delimited between the base body and the sleeve body, wherein the base body and the sleeve body each have an annular recess, whereby a step is formed, the two flanks of which complement each other to form a first side wall of the channel, which is arranged on the side of the sealing ring opposite the applied fluid pressure and between which the sealing gap to be sealed opens.As a result, the sealing gap facing away from the pressure and to be sealed by the sealing ring is not located on an extension of the sealing surface against which the sealing ring seals, as in the prior art, but offset from it.

[0016] The step on the two sealing surfaces of the components ensures that the gap on the side facing away from the pressure does not directly adjoin the sealing surface. This means that even in the event of gap extrusion, no material from the sealing ring that seals against the sealing surface extrudes into the sealing gap, which would directly impair the preload of the seal. Rather, only material from the seal or the support ring that is a certain distance from the sealing surface can extrude into the sealing gap. This effectively prevents any impairment of the preload of the sealing ring against the sealing surface, further increasing the pressure resistance of the coupling element.

[0017] In a further development of the invention, the recess in the base body or the sleeve body is formed by a groove whose opposing flanks have different heights. This achieves axial fixation of the sealing ring and an offset between the sealing surface and the sealing gap.

[0018] In one embodiment of the invention, the second groove flank opposite the sealing gap has a greater height than the opposite first groove flank, with the height of the second groove flank preferably corresponding to the height of the first side wall of the channel. This maximizes the axial contact surface for the sealing ring.

[0019] In a further embodiment of the invention, the second groove flank is formed by an additional component. This enables damage-free installation of the sealing ring.

[0020] In one embodiment of the invention, a support ring is arranged axially adjacent to the sealing ring, preferably on the side facing the sealing gap. This counteracts pressure-induced deformation of the sealing ring.

[0021] In a further embodiment of the invention, the first side wall of the channel, which contains the sealing gap to be sealed, extends parallel to the coupling axis, with the second side wall of the channel being formed by the tappet guide. This achieves a reliable seal between the tappet guide and the housing of the coupling element.

[0022] Further developments and refinements of the invention are specified in the remaining subclaims. An embodiment of the invention is illustrated in the drawings and described in detail below. They show: Fig. 1 the schematic representation of a coupling sleeve of a hydraulic coupling according to the prior art a) in longitudinal section; b) in the detail section Z (sealing area); c) in detail section Y (ram holder); Fig. 2 the schematic representation of a coupling plug of a hydraulic coupling according to the prior art a) in longitudinal section; b) in the detail section Z (sealing area); Fig. 3 the schematic representation of a coupling sleeve of a hydraulic coupling a) in longitudinal section; b) in the detail section Z (sealing area); c) in detail section Y (ram receiving area Y) Fig. 4 the schematic representation of a coupling plug of a hydraulic coupling a) in longitudinal section; b) in detail section Y (sealing area); Fig. 5 shows a hydraulic coupling with a coupling sleeve and a coupling plug connected to it; Fig. 6 the detailed view of section X of the hydraulic coupling from Fig. 5.

[0023] The example shown in Fig. 3 selected coupling sleeve 1 comprises a housing 2 with a sealing unit 3. The housing 2 delimits a flow channel 28 for a pressure medium, wherein the housing 2 extends substantially rotationally symmetrically about a coupling axis A.

[0024] The housing 2 comprises a base body 21, a first sleeve body 24 connected to the base body, and a second sleeve body 25 surrounded by the first sleeve body 24 and axially clamped between the base body 21 and the first sleeve body 24. A closure sleeve 27 is displaceably arranged on the outside of the first sleeve body 24. A tappet guide 4 is also axially clamped between the second sleeve body 25 and the base body 21. In the exemplary embodiment, this tappet guide 4 is formed from two holding elements 41 and accommodates the valve tappet 31 of the sealing unit 3.

[0025] The base body 21 of the housing 2 is essentially hollow-cylindrical and has, at its end facing the first sleeve body 24, a section 211 with an enlarged inner diameter, which is provided with an internal thread 212. The section 211 with an enlarged inner diameter defines an end face 22, into which an annular first step 23 is introduced.

[0026] The first sleeve body 24 has, on its inner side facing the valve tappet 31, a first shoulder 241 with an enlarged inner diameter, which at the end merges into a second shoulder 242 with an enlarged inner diameter. Opposite the second shoulder 242, the first sleeve body 24 is provided with an external thread 243.

[0027] The second sleeve body 25 has, at its end facing the base body 21, an outwardly projecting annular flange 251, which has an annular second step 26 at its end. Opposite the annular flange 251, the second sleeve body 25 has a third shoulder 252 with an enlarged inner diameter, into which the holding elements 41 of the tappet guide 4 extend.

[0028] The first sleeve body 25 is screwed with its external thread into the internal thread 212 of the base body 21, whereby the first sleeve body 25 clamps the annular flange 251 of the second sleeve body 25, which extends into its second shoulder 242, against the end face 22 of the base body 21. At the same time, the portions of the holding elements 41 projecting into the third shoulder 252, which has an enlarged inner diameter, are clamped against the end face 22 of the base body 21.

[0029] Here, the second step 26 of the second sleeve body 25 is arranged opposite the first step 23 of the base body 21, with the two flanks of the two steps 23, 26 complementing each other to form a first side wall 531, between which a sealing gap 55 opens. Arranged parallel to this first side wall 531 are the retaining elements 41, which form a second side wall 532 of the annular channel 53 formed between the base body 21, the second sleeve body 25, and the retaining elements 41 of the tappet guide 4. Arranged in the channel 53 is a support ring 52, adjacent to the first side wall 531, and an O-ring 51, adjacent thereto. The support ring 52 and the O-ring 51 are prestressed against the sealing surface 54 of the base body 21, which is delimited by the first step 23 and the two retaining elements 41. The sealing surface 54 is arranged axially offset from the sealing gap 55. The sealing arrangement 5 thus formed is in Fig. 3 b) shown.

[0030] The sealing unit 3 comprises the valve tappet 31 received by the tappet guide 4, a valve sleeve 36 slidably arranged between the second sleeve body 25 and the valve tappet for sealing engagement with a piston seal 35 arranged on the valve piston 32 of the valve tappet 31 and fixed via a chambering sleeve 351, and a pressure sleeve 37 slidably arranged between the first sleeve body 24 and the second sleeve body 25. The valve sleeve 36 is preloaded against the piston seal 35 by a compression spring 38. The pressure sleeve 37 has an annular collar 371 at its end facing away from the tappet guide 4, which forms a common plane with the outward-facing side of the valve piston 32. At its end facing away from the collar 371, a circumferential outwardly projecting web 372 is arranged on the pressure sleeve 37, which web rests against the first shoulder 241 of the first sleeve body 24, against which it is prestressed by a further compression spring 38.

[0031] In an end region of the valve tappet 31, a circumferential groove 34 is formed in the tappet shaft 33, into which two retaining elements 41 of the tappet guide 4 are inserted. The first groove flank 341 of the groove 34 facing the valve piston 32 is arranged orthogonally to the central axis of the tappet shaft 33. The second groove flank 342 of the groove 34, opposite the first groove flank 341, is inclined outwards and forms a cone which, in the exemplary embodiment, has a cone angle α of 130°. The outer contour of the sections of the retaining elements 41 inserted into the groove 34 are designed to correspond to the inner contour of the groove 34 (cf. Fig. 3 c)). The valve tappet 31 is held stationary in the housing 2 via the tappet guide 4. Instead of the circumferential groove 34, a plurality of grooves can be arranged circumferentially in the tappet shaft 33, offset from one another and spaced apart from one another, each of which receives a retaining element and whose second groove flank is each inclined outwards and lies on a common imaginary cone.

[0032] The example shown in Fig. 4 selected coupling plug 6 comprises a housing 7, with a sealing unit 8. The housing 7 delimits a flow channel 75 for a pressure medium, wherein the housing 7 extends substantially rotationally symmetrically about a coupling axis A.

[0033] The housing 7 is formed from a base body 71 onto which a plug sleeve 73 is screwed. The base body 71 is essentially hollow-cylindrical and has a section 711 with a reduced outer diameter at its end, which has an external thread 712, to which a first step 72 is connected. The plug sleeve 73 has, at its end facing the base body 71, a section 731 with an enlarged inner diameter, which is provided with an internal thread 732. Adjacent to the internal thread is a groove 74, which is delimited by a first groove flank 743 and a second groove flank 744 opposite it, and which forms a second step 741 and, opposite this, a third step 742.At its end opposite the section 731 with the enlarged inner diameter, an annular groove 76 is provided in the plug sleeve, into which a profile seal prestressed with two O-rings 761 is inserted for sealing against the valve piston 81 of the sealing unit 8.

[0034] The plug sleeve 73 is screwed with its internal thread 732 onto the external thread 712 of the base body 71. The second step 741 of the plug sleeve 73 is arranged opposite the first step 72 of the base body 71, with the two flanks of the two steps 72, 741 complementing each other to form a first side wall 931, between which a sealing gap 95 opens.

[0035] The third step 742 formed by the groove 74 is arranged parallel to this first side wall 931, with the second groove flank 744 of the groove 74 forming a second side wall 932 of the annular channel 93 formed between the outer diameter-reduced section 711 of the base body 71 and the inner diameter-expanded section 731 of the plug sleeve 71. The width of the third step 742 corresponds to the width of the first side wall 931 of the channel 93 formed by the first step 72 of the base body 71 and the second step 741 of the plug sleeve.

[0036] In the channel 93, a support ring 92 is arranged adjacent to the first side wall 931, as well as an O-ring 91. The support ring 92 and O-ring 91 are prestressed against the sealing surface 94 of the base body 71, which is delimited by the first step 72 of the base body 71 and the second step 741 of the plug sleeve 73. The sealing surface 94 is arranged radially offset from the sealing gap 95. The sealing arrangement 9 thus formed is in Fig. 4 b) shown.

[0037] The sealing unit 8 comprises a valve piston 81, which is slidably guided in the housing 7 and preloaded into the closed position by a compression spring 83. The valve piston 81 has passages 82 for the passage of pressure medium from the flow channel 75. In the closed position of the valve piston 81, the profile seal arranged in the annular groove 76 of the plug sleeve 73, preloaded by the two O-rings 761, lies sealingly against the valve piston 81.

[0038] In Fig. Figure 5 schematically shows a coupling with a coupling sleeve 1 and a coupling plug 6. By inserting the coupling plug 6 into the coupling sleeve 1, the pressure sleeve 37 of the coupling sleeve 1 is moved by the plug sleeve 73 of the coupling plug 6 against the preload of the compression spring 38 in the direction of the base body 21, taking the valve sleeve 36 with it. On the other hand, the valve piston 81 of the coupling plug 6 is moved by the fixed valve tappet 31 of the coupling sleeve 1 against the preload of the compression spring 38, whereby the flow channel 28 of the coupling sleeve 1 is connected to the flow channel 75 of the coupling plug 6.

Claims

[1] Coupling element, in particular a coupling sleeve (1), for a hydraulic coupling on a pressure medium line, comprising a housing (2, 7) and a sealing unit (3, 8), wherein the housing (2, 7) has a flow channel (28, 75) for a pressure medium and a coupling axis (A), and wherein the sealing unit (3) comprises a valve tappet (31) with a valve piston (32) which is held in a tappet guide (4) which is connected to the housing (2), wherein the valve tappet (31) has at least one groove (34) with a first groove flank (341) facing the valve piston (32) and a second groove flank (342) opposite said first groove flank and facing away from the valve piston (32), into which the tappet guide (4) engages, whereby the tappet guide (4) and the valve tappet (31) are positively connected, characterized by that the second groove flank (342) of the at least one groove (34) facing away from the valve piston (32) of the valve tappet (31) is designed to widen conically outwards. [2] Coupling element according to claim 1, characterized by that the tappet guide (4) is formed from at least two holding elements (41). [3] Coupling element according to claim 1 or 2, characterized by that the second groove flank (342) of the at least one groove has a cone angle of between 50° and 140°, preferably between 60° and 130°, particularly preferably between 70° and 120°. [4] Coupling element according to one of the preceding claims, characterized by that the first groove flank of the at least one groove (34) opposite the second groove flank extends orthogonally to the coupling axis (A). [5] Coupling element according to one of the preceding claims, characterized bythat the housing (2, 7) is formed from a base body (21, 71) and at least one sleeve body (24, 25, 73) connected to it in a form-fitting and / or force-fitting manner, wherein the base body (21, 71) and a sleeve body (25, 73) of the at least one sleeve body delimit an annular channel (53, 93) with a preferably rectangular cross-section, in which a sealing ring, preferably an O-ring (51, 91) for sealing a sealing gap (55, 95) delimited between the base body (21, 71) and the sleeve body (25, 73) is arranged, wherein the base body (21, 71) and the sleeve body (25, 73) each have an annular recess, whereby a step (23, 26, 72, 741) is formed, the two flanks of which extend to a first Side wall (531, 741) of the channel (53, 93), which is arranged on the side of the sealing ring opposite the applied fluid pressure and between which the sealing gap (55, 95) to be sealed opens. [6] Coupling element according to claim 5, characterized by that the recess in the base body (21, 71) or the sleeve body (25, 73) is formed by a groove (74) whose opposite groove flanks (743, 744) have a different height. [7] Coupling element according to claim 6, characterized by that the second groove flank (744) of the groove (74) opposite the sealing gap (55, 95) has a greater height than the opposite first groove flank (743), wherein the height of the second groove flank preferably corresponds to the height of the first side wall (531, 931) of the channel (53, 93). [8] Coupling element according to claim 7, characterized by that the second groove flank (744) is formed by a separate component. [9] Coupling element according to one of claims 5 to 8, characterized bythat the first side wall (531) of the channel (53) having the sealing gap (55) to be sealed extends parallel to the coupling axis (A), wherein the second side wall (532) of the channel (53) is formed by the tappet guide (4). [10] Coupling element according to one of claims 5 to 9, characterized by that a support ring (52, 92) is arranged axially next to the sealing ring, preferably on its side facing the sealing gap (55, 95).

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