Improved lubrication for hydraulic press seals

Abstract

A hydraulic press (1) is disclosed, comprising a first assembly (10) and a second assembly (20) rotatable relative to each other about a rotation axis (X-X), wherein the first assembly (10) and the second assembly (20) define an internal volume (2) and are in contact at an interface, the interface between the first assembly (10) and the second assembly (20) being provided with a sealing element (40) located in a recess (30) connected on the one hand to the internal volume (2) by a first duct and on the other hand to the surrounding environment by a second duct (5), the first duct being provided with a sealing element (6) adapted to isolate the recess (4) from the internal volume (2), characterized in that a secondary cavity (7) is formed in the first assembly (10) or in the second assembly (20), said secondary cavity (7) being connected to the recess (4) and isolated from the internal volume (2).

Description

Technical Field

[0001] This disclosure relates to improved sealing devices for hydraulic presses, and more particularly to a sealing device with an improved lubrication system. Background Technology

[0002] Using hydraulic presses in different environments can present sealing challenges. In fact, a recurring problem is preventing impurities from entering the internal volume of the hydraulic press's crankcase.

[0003] Different sealing structures have been proposed to ensure a good seal between the internal volume of the hydraulic press and the external environment. However, known solutions still have reliability issues, especially over time.

[0004] The initial installation involves placing a single axial sealing element to ensure isolation between the surrounding environment and the internal volume of the crankcase. However, under increased pressure in the crankcase, the sealing element may leak from its housing or be damaged, for example, due to tearing or, in the case of a metal seal, due to jamming of the sliding contact surfaces. This results in high friction and efficiency loss in the case of a metal seal. For example, such a pressure increase in the crankcase is caused by the start-up of a cold hydraulic press. Pressurized oil reaches the machine's crankcase through internal leaks common in these machines, and the crankcase oil cannot easily escape through the crankcase drain pipe, which is still filled with cooling oil, resulting in a very high pressure drop due to the high viscosity of the cooling oil. This operation can quickly damage the sealing element. In particular, if the pressure in the machine's crankcase increases, the increased support force between the sliding parts of the sealing element can subsequently cause jamming, thus damaging the sealing element. Components of the sealing element may also be damaged by the pressure.

[0005] Alternatively, the axial sealing element, which ensures isolation between the interior and exterior of the hydraulic press, can be housed in a dedicated housing. This housing itself is isolated from the internal volume of the crankcase of the hydraulic press (e.g., a hydraulic press) by a crankcase seal, which is typically considered an absolute seal. This associates a dynamic sealing element (e.g., a lip ring) with a dynamic sealing element that resists potential peak pressures, such as an O-ring coupled to an annular element. However, such an installation thus defines a closed chamber between the axial sealing element and the crankcase sealing element. This closed chamber, however, presents lubrication problems. In effect, the housing containing the axial sealing element is completely isolated from the internal volume of the crankcase by the crankcase seal, and therefore the housing is not continuously lubricated. However, lack of lubrication can lead to rapid damage to the axial sealing element, especially as the pressure in the housing increases due to seizing caused by lack of oil or heating, leading to the discharge of existing oil, which exacerbates the problem. A commonly proposed solution involves filling the housing with a predetermined amount of oil, which must be changed periodically. However, it should be understood that this solution is highly limiting and requires specialized maintenance operations. Furthermore, these solutions raise space requirements for storing sufficient oil in the housing, resulting in axial space requirements that are incompatible with the structure of hydraulic presses that are subject to strict space constraints.

[0006] Therefore, this disclosure is intended to at least partially address these problems. Summary of the Invention

[0007] To this end, this disclosure proposes a hydraulic press comprising a first component and a second component rotatable relative to each other about a rotation axis, the first component and the second component defining an internal volume and contacting each other along an interface, the interface between the first component and the second component being provided with a sealing element positioned within a housing, the housing being connected to the internal volume on one hand via a first conduit and to the surrounding environment on the other hand via a second conduit, the first conduit being provided with a sealing element suitable for isolating the housing from the internal volume.

[0008] The sealing element is characterized as an axial sealing element comprising a first metal ring and a second metal ring, a first elastic ring and a second elastic ring, wherein the first metal ring and the second metal ring are supported and abutted against each other along an axial direction defined by a rotation axis, the first elastic ring is supported and abutted against the first metal ring on one side and supported and abutted against the partition wall of the first assembly on the other side, the second elastic ring is supported and abutted against the second metal ring on one side and supported and abutted against the partition wall of the second assembly on the other side, wherein a secondary cavity is formed in the first assembly or the second assembly, the secondary cavity being connected to the housing and typically isolated from the internal volume by means of a hole or pipe.

[0009] According to one example, the secondary cavity is formed in a portion of the crankcase of the hydraulic press.

[0010] The hydraulic press includes, for example, at least one bearing located in a housing, supporting abutment against a first shoulder formed in a first assembly and a second shoulder formed in a second assembly, with a secondary cavity leading to the housing surrounding the bearing relative to the axis of rotation.

[0011] According to one example, the secondary cavity extends in a 360° angular sector around the axis of rotation.

[0012] According to one example, the secondary cavity is connected to the housing via a plurality of holes formed in the first component.

[0013] The hole then typically extends around the axis of rotation along an angular sector of less than or equal to 180°.

[0014] According to one example, the housing is then formed to extend at least partially around a rolling element between the first and second components relative to the axis of rotation.

[0015] As a variation, the secondary cavity is formed in the shaft of the hydraulic press.

[0016] According to one example, the secondary cavity is connected to the housing (4) through multiple separate holes formed in the shaft.

[0017] According to one example, the dimensions of the secondary cavity are configured such that the total volume of the housing and the secondary cavity is greater than or equal to 300 mL.

[0018] According to one example, the secondary cavity is connected to the surrounding environment via a secondary orifice, which is provided with a plug.

[0019] For example, a hydraulic press is a hydraulic press that includes a cylinder block having multiple housings extending radially relative to the axis of rotation, within which the cylinder and a multi-cam surrounded by the cylinder block are located. Such a hydraulic press can, for example, represent the operation of a hydraulic motor or a hydraulic pump. Attached Figure Description

[0020] The invention and its advantages will be better understood by reading the following detailed description of different embodiments of the invention given by way of non-limiting examples.

[0021] [ Figure 1 ] Figure 1 A cross-sectional view of a hydraulic press portion according to one aspect of the present invention is shown.

[0022] [ Figure 2 ] Figure 2 It can be used to form Figure 1 A perspective view of an example of a hydraulic press casting core.

[0023] [ Figure 3 ] Figure 3 This is a partial cross-sectional view of another example of a hydraulic press according to one aspect of the present invention.

[0024] In all the figures, common elements are identified by the same numerical reference. Detailed Implementation

[0025] Now for special reference Figure 1 and Figure 2 An exemplary embodiment of the present invention is described below.

[0026] Figure 1 This is a partial sectional view of a hydraulic press 1. The hydraulic press 1 includes a first component 10 and a second component 20 that are rotatable relative to each other along a rotation axis X–X. In the following description, unless otherwise stated, “radial” and “axial” are defined relative to the rotation axis X–X.

[0027] In the example shown, rotational guidance is ensured by rolling elements (here, tapered bearings 32 and 34 forming bearing 30). It should be understood that this exemplary embodiment is not limiting, and the rolling elements can be of any type. The hydraulic press 1 includes an internal volume 2 in which various components, depending on their nature, are arranged, such as a radial or axial piston hydraulic motor, a radial or axial piston hydraulic pump, a braking system, or any other device having two components that rotate relative to each other.

[0028] The first component 10 and the second component 20 represent different parts of the hydraulic press 1. For example, one of these components may include the shaft and cylinder body of the hydraulic press, while another of these components may include the multi-cam cam and distributor of the hydraulic press. The first component 10 and the second component 20 may include braking devices, such as discs, adapted to prevent relative rotational movement of the first component 10 relative to the second component 20 under frictional action between the discs.

[0029] For such hydraulic presses, a hydraulic power circuit is typically defined, with suction and delivery lines, distributor lines, and the piston chamber of the cylinder body connected to this hydraulic power circuit. The hydraulic power circuit typically includes a hydraulic pump that defines supply and return branches, or high-pressure (HP) and low-pressure (LP) branches, within the hydraulic circuit. The hydraulic circuit can be open-loop or closed-loop. The hydraulic power circuit ensures the transmission of hydraulic power.

[0030] This hydraulic press also defines an internal volume 2, which corresponds to the volume contained in the crankcase surrounding the various components of the hydraulic press 1. The internal volume 2 is isolated from the hydraulic power circuit by seals (typically piston seals and distributor seals) in a manner known to those skilled in the art. The internal volume 2 of the hydraulic press receives oil flow from the power circuit leaking from within the hydraulic press, and the power circuit is typically connected to a tank via a drain pipe to discharge this oil flow, such that the pressure in the internal volume of the hydraulic press is maintained substantially equal to the pressure in the tank, which is typically equal to or close to atmospheric pressure.

[0031] The internal volume 2 of the hydraulic press 1 is isolated from the external environment by a first sealing element 40 disposed in the housing 4. The housing 4 is connected to the external environment via a pipe 5. In the example shown, the first sealing element 40 is an axial seal or a floating seal, commonly referred to as a double cone seal.

[0032] Here, the first sealing element 40 includes a first metal ring 41 and a second metal ring 43 made of metallic material, which are generally symmetrical about a plane that extends radially with respect to the axis of rotation X–X. The first sealing element 40 also includes a first elastic ring 42 and a second elastic ring 44 made of elastic material.

[0033] The first metal ring 41 and the second metal ring 43 support and abut against each other along the axial direction defined by the rotation axis X–X.

[0034] The first elastic ring 42 is supported by the first metal ring 41 on one side and supported by the partition wall 14 of the first component 10 on the other side.

[0035] The second elastic ring 44 is supported by the second metal ring 43 on one side and supported by the partition wall 24 of the second component 20 on the other side.

[0036] The first elastic ring 42 and the second elastic ring 44 are typically radially positioned outward relative to the first metal ring 41 and the second metal ring 43. The first metal ring 41 and the second metal ring 43 press the first elastic ring 42 and the second elastic ring 44 against the partition wall 14 of the first component 10 and the partition wall 24 of the second component 20, respectively, thereby ensuring a sealed connection.

[0037] The first metal ring 41, the second metal ring 43, the partition wall 14 of the first component 10, and the partition wall 24 of the second component 20 are generally configured such that the first elastic ring 42 and the second elastic ring 44 tend to move the first metal ring 41 and the second metal ring 43 against each other along the axial direction defined by the rotation axis X–X.

[0038] As mentioned above, the issues associated with this type of installation involve the lubrication of the first sealing element 40. In conventional structures, the housing 4 is typically isolated from the internal volume 2 by a seal considered absolute, which usually includes a dynamic seal (e.g., a lip ring) coupled to a reinforced seal specifically adapted to withstand any peak pressure. However, this installation completely isolates the housing 4 from the internal volume 2, thus requiring lubrication by design, for example, by introducing a predetermined amount of oil into the housing 4. However, as oil gradually leaks towards the external environment, periodic maintenance operations are required to reintroduce oil into the housing 4. Furthermore, hydraulic presses, such as hydraulic units or devices, typically have significant limitations in terms of axial space requirements, which do not allow for sufficient volume to ensure the lubrication of the first sealing element 40 and to prevent potential pressure increases in the housing 4 due to heating caused by the reduced amount of oil in the housing 4. However, this sealing element 40, comprising two metal elements rotating relative to each other, requires much higher levels of lubrication than a dynamic sealing element (e.g., a lip ring), thus necessitating a specific solution. Common solutions proposed for other dynamic seals do not truly guarantee adequate lubrication of such sealing elements.

[0039] To address these issues, the proposed structure includes a secondary cavity 7 formed within the first component 10 or the second component 20 and connected to the housing 4 to provide additional reserve volume without affecting the axial space requirements of the hydraulic press 1. The secondary cavity 7 is connected to the housing 4 via multiple pipes or channels, which may be integrally cast or machined, for example, by drilling.

[0040] The housing 4 is isolated from the internal volume 2 by a second sealing element 6 (e.g., a lip ring type dynamic seal). Thus, the second sealing element 6 defines the gap between the housing 4 and the internal volume 2.

[0041] Here, the bearing 30 is formed by two rolling elements 32 and 34 disposed on both sides of the second sealing element 6. Therefore, the rolling element 34 is disposed in the housing 4, while the rolling element 32 is disposed in the internal volume 2.

[0042] exist Figure 1 In the illustrated embodiment, the secondary cavity 7 is formed within the first assembly 10, and more specifically, within a section of the crankcase of the hydraulic press 1, forming part of the first assembly 10 and at least partially surrounding the rolling element 34. The component in question can be substantially modified to increase its radial space requirements, thereby allowing the formation of a secondary cavity 7 with sufficient volume. The secondary cavity 7 is typically integrally cast.

[0043] More specifically, the rolling element 34 is supported on one side against the shoulder 13 of the first assembly 10 and on the other side against the shoulder 23 of the second assembly 20. The volume of the first assembly 10 is recessed to form the secondary cavity 7. This volume extends radially around the rolling element 34.

[0044] The secondary cavity 7 typically extends over a 360° angular sector around the rotation axis X–X. As a variation, the secondary cavity 7 may extend over the rotation axis X–X only over a limited angular sector (e.g., over an angular sector less than or equal to 180°).

[0045] As seen in the figure, the secondary cavity 7 extends at least partially around at least one of the rolling elements (here, rolling element 34) relative to the rotation axis X–X. This configuration is advantageous in terms of compactness because it eliminates the need for the assembly to extend along the rotation axis X–X.

[0046] The secondary cavity 7 is connected to the housing 4 via a plurality of individual holes 71 formed in the first assembly 10 or in a continuous rib extending over the entire periphery of one side of the internal volume 4. The holes 71 shown are formed to extend partially around the outer surface of the outer ring of the rolling element 34 without affecting its retention by the shoulder 13.

[0047] The secondary cavity 7 is provided with a secondary opening 72 leading to the surrounding environment, which is sealed by a plug 8.

[0048] Figure 2 Showing the use of in Figure 1 The diagram shows a perspective view of a core forming a secondary cavity 7 in a portion of the crankcase of a hydraulic press; thus, the core 700 allows visualization of an example of the geometry of the second cavity 7.

[0049] The cast core 700 shown includes a central section 701 and a peripheral section 702. The central section 701 defines a central cavity for the crankcase portion, while the peripheral section defines the shape of the secondary cavity 7. Since the central section 701 is connected to the peripheral section 702 via a plurality of radial conduits 710, these radial conduits 710 define the aforementioned individual holes 71 that connect the secondary cavity 7 to the housing 4.

[0050] It should be understood that the number and distribution of the radial conduits 710 (and therefore the holes 71) can vary. In the example shown, the holes 71 are uniformly distributed around the axis of rotation X–X on the entire inner circumference of the components of the first assembly 10 (e.g., the crankcase portion). As a variation, the holes 71 may extend around the axis of rotation X–X only in limited angular sectors, for example, such that the angular sectors corresponding to areas of the first assembly 10 subjected to higher mechanical stresses do not have holes 71. For example, the holes 71 may extend around the axis of rotation X–X only in angular sectors less than or equal to 180°, such as angular sectors opposite the anchoring point of the hydraulic press 1, or angular sectors opposite the attachment points of equipment components or elements driven by the hydraulic press 1, such as angular sectors opposite the anchoring point of a track driven by the hydraulic press 1.

[0051] like Figure 2 The illustrated core 700 includes conduits 720 extending radially around a peripheral segment 702. These conduits 720 specifically allow for the formation of one or more secondary orifices 72 as described above.

[0052] Secondary orifice 72 specifically allows for the formation of filling and / or venting orifices for oil present in the secondary cavity 7 and housing 4, thus ensuring simplified intervention for these operations without the need to disassemble the hydraulic press 1.

[0053] The secondary chamber 7 is typically sized such that the total volume of the housing 4 and the secondary chamber 7 allows for the reception of 150 mL or more of oil, while maintaining an air volume consistent with recommendations for the sealing element under consideration, for example, at least 30% or at least 50% of that volume is filled with air, and for example, less than 75% of that volume is filled with air. Therefore, the total volume of the housing 4 and the secondary chamber 7 is typically greater than 200 mL, 220 mL, or 300 mL.

[0054] The secondary cavity 7 may have radial ribs, particularly to enhance the mechanical properties of the component in which the secondary cavity 7 is formed. Thus, the secondary cavity 7 may be divided into several separate cavities, which are connected to the housing 4 via holes 71.

[0055] The proposed hydraulic press structure includes a secondary cavity 7 as defined above, which allows for the solution of the aforementioned problem of ensuring adequate lubrication of the first sealing element 40 present in the housing 4, while avoiding an increase in the axial space requirements of the hydraulic press. The embodiment shown, including the secondary orifice 72, also simplifies the operation of draining and adding oil in the secondary cavity 7 and the housing 4 without requiring disassembly of the hydraulic press 1.

[0056] Figure 3 Another exemplary embodiment of the hydraulic press 1 according to one aspect of this disclosure is shown.

[0057] In this embodiment, the secondary cavity 7 is formed in a component of the second assembly 20, namely, in the hydraulic press shaft in the example shown.

[0058] In this embodiment, the secondary cavity 7 is formed by a hole formed in a shaft, which is here a component of the second assembly 20. The hole is blind and open at the free end of the hydraulic press 1. The through end 73 of the secondary cavity 7 can be sealed by a plug (such as a sealing plate) that must be placed in the housing 73, or by... Figure 3 Blocking by any other suitable means not shown in the diagram.

[0059] The secondary cavity 7 is connected to the housing 4 via a radial hole 71 formed in the shaft. In the example shown, the secondary cavity 7 has a hole 71 formed on either side of the rolling element 34. Therefore, one or more individual holes 71 can be formed in the shaft of the hydraulic press 1. It should be understood that this embodiment is not limiting, and the secondary cavity 7 formed in the shaft can be connected to the housing 4 via any number of holes 71, which may or may not extend radially.

[0060] The function of secondary cavity 7 is similar to that described in the reference above. Figure 1 and Figure 2 The function is to ensure adequate lubrication of the components arranged in the housing 4 without increasing the axial space requirements of the hydraulic press 1.

[0061] According to one example, the volume of the secondary cavity 7 is greater than or equal to the volume of the shell 4.

[0062] Figure 3 The illustrated embodiment is particularly suitable for hydraulic presses where the shaft does not bear high loads.

[0063] Therefore, the proposed different embodiments allow for solving the lubrication problem of components that ensure the hydraulic press is sealed relative to the surrounding environment without increasing radial space requirements.

[0064] Although the invention has been described with reference to specific exemplary embodiments, it will be apparent that modifications and changes can be made to these examples without departing from the general scope of the invention as defined by the claims. In particular, individual features of different illustrated / mentioned embodiments may be combined in additional embodiments. Therefore, the specification and drawings should be considered in an illustrative rather than restrictive sense.

[0065] It is equally evident that all features described with reference to a method can be applied individually or in combination to a device, and conversely, all features described with reference to a device can be applied individually or in combination to a method.

Claims

1. A hydraulic press (1) comprising a first component (10) and a second component (20) rotatable relative to each other about a rotation axis (X–X), the first component (10) and the second component (20) defining an internal volume (2) and contacting each other along an interface, the interface between the first component (10) and the second component (20) being provided with a sealing element (40), the sealing element (40) being positioned in a housing (4), the housing being connected on one hand to the internal volume (2) via a first conduit and on the other hand to the surrounding environment via a second conduit (5). The first conduit is provided with a sealing element (6) suitable for isolating the housing (4) from the internal volume (2). Its features are, The sealing element (40) located at the interface between the first component (10) and the second component (20) is an axial sealing element, comprising a first metal ring (41) and a second metal ring (43), a first elastic ring (42) and a second elastic ring (44), wherein the first metal ring (41) and the second metal ring (43) are supported and abutted against each other along an axial direction defined by the rotation axis (X–X), the first elastic ring (42) is supported and abutted against the first metal ring (41) on one hand and supported and abutted against the partition wall (14) of the first component (10) on the other hand, and the second elastic ring (44) is supported and abutted against the second metal ring (43) on one hand and supported and abutted against the partition wall (24) of the second component (20) on the other hand. in: A secondary cavity (7) is formed in the first component (10), the secondary cavity (7) being isolated from the internal volume (2) and connected to the housing (4) through a plurality of holes (71) formed in the first component (10), the plurality of holes (71) extending about the rotation axis (X–X) in an angular sector of less than or equal to 180°; or A secondary cavity (7) is formed in the second component (20), which is isolated from the internal volume (2) and connected to the housing (4) through a plurality of holes (71) formed in the second component (20), which extend in angular sectors less than or equal to 180° around the axis of rotation (X–X).

2. The hydraulic press (1) according to claim 1, wherein the secondary cavity (7) is formed in a portion of the crankcase of the hydraulic press (1).

3. The hydraulic press (1) according to claim 1, comprising at least one bearing (34) located in the housing (4), the at least one bearing supporting abutting against a first shoulder (13) formed in the first assembly (10) and abutting against a second shoulder (23) formed in the second assembly (20), the secondary cavity (7) opening relative to the axis of rotation (X–X) to the housing (4) surrounding the bearing (34).

4. The hydraulic press (1) according to claim 1, wherein the secondary cavity (7) extends in a 360° angular sector around the axis of rotation (X–X).

5. The hydraulic press (1) according to claim 1, wherein the housing (4) is formed to extend at least partially around a rolling element (34) between the first component (10) and the second component (20) relative to the axis of rotation (X–X).

6. The hydraulic press (1) according to claim 1, wherein the secondary cavity (7) is formed in the shaft of the hydraulic press (1).

7. The hydraulic press (1) according to claim 6, wherein the secondary cavity (7) is connected to the housing (4) through a plurality of separate holes (71) formed in the shaft.

8. The hydraulic press (1) according to claim 1, wherein the secondary cavity (7) is sized such that its volume is greater than or equal to the volume of the housing (4).

9. The hydraulic press (1) according to claim 1, wherein the secondary cavity (7) is connected to the surrounding environment through a secondary orifice (72), and the secondary orifice is provided with a plug (8).

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