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JP-7856583-B2 - Improved lubrication system for hydraulic machinery sealing

JP7856583B2JP 7856583 B2JP7856583 B2JP 7856583B2JP-7856583-B2

Inventors

  • フレイ，アダム
  • ジャラベール，パトリック
  • ナセール，ローラン

Assignees

  • ポクラン イドロリク アンドゥストリ

Dates

Publication Date
20260511
Application Date
20210524
Priority Date
20200525

Claims (9)

  1. A hydraulic machine (1) comprising a first assembly (10) and a second assembly (20) that are rotatable relative to each other around a rotation axis (X-X), The first assembly (10) and the second assembly (20) define an internal volume (2) and are in contact via an interface. The interface between the first assembly (10) and the second assembly (20) is The device comprises a rolling element and a housing ( 4 ) which is connected on one side to the internal volume (2) via a first duct and on the other side to the surrounding environment via a second duct (5), and a sealed element (40) disposed within it. The first duct is A hydraulic machine (1) having a sealing element (6) adapted to isolate the housing (4) from the internal volume (2), The sealing element (40) is an axial sealing element comprising a first metal annular portion (41), a second metal annular portion (43), a first elastomer annular portion (42), and a second elastomer annular portion (44), wherein the first metal annular portion (41) and the second metal annular portion (43) support each other along the axial direction defined by the rotation axis (X-X), the first elastomer annular portion (42) is attached with support on one side to the first metal annular portion (41) and on the other side to the partition wall (14) of the first assembly (10), and the second elastomer annular portion (44) is attached with support on one side to the second metal annular portion (43) and on the other side to the partition wall (24) of the second assembly (20). The secondary cavity (7) is formed within the first assembly (10) and connected to the housing (4) via a plurality of bores (71) formed in the first assembly (10), or A secondary cavity (7) is formed within the second assembly (20) and connected to the housing (4) via a plurality of bores (71) formed in the second assembly (20). The plurality of bores (71) extend over an angular sector of 180° or less around the axis of rotation (X-X), A hydraulic machine (1) characterized in that the secondary cavity (7) is isolated from the internal volume (2).
  2. The hydraulic machine (1) according to claim 1, wherein the secondary cavity (7) is formed within a portion of the crankcase of the hydraulic machine (1).
  3. The hydraulic machine (1) according to claim 1, comprising at least one bearing (34) disposed within the housing (4) and supporting, on one side, a first shoulder portion (13) formed in the first assembly (10), and on the other side, a second shoulder portion (23) formed in the second assembly (20), wherein the secondary cavity (7) opens into the housing (4) around the bearing (34) with respect to the axis of rotation (X-X).
  4. The hydraulic machine (1) according to claim 1, wherein the secondary cavity (7) extends over a 360° angular sector around the axis of rotation (X-X).
  5. The hydraulic machine (1) according to claim 1, wherein the housing (4) is formed to extend at least partially around a rolling element (34) interposed between the first assembly (10) and the second assembly (20) with respect to a rotation axis (X-X).
  6. The hydraulic machine (1) according to claim 1, wherein the secondary cavity (7) is formed within the second assembly (20) , which is the shaft of the hydraulic machine (1).
  7. The hydraulic machine (1) according to claim 6, wherein the secondary cavity (7) is connected to the housing (4) via a plurality of separate bores (71) formed within the shaft.
  8. The hydraulic machine (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 machine (1) according to claim 1, wherein the secondary cavity (7) is connected to the surrounding environment via a secondary orifice (72), and a plug (8) is provided in the secondary orifice ( 72).

Description

This disclosure relates to an improved sealing device for hydraulic machinery, and more particularly to a sealing device in which an improved lubrication system is proposed. Because hydraulic machinery is used in a variety of environments, ensuring airtightness is a challenge. In fact, preventing impurities from entering the internal volume of the crankcase of hydraulic machinery is a recurring challenge. Various sealing structures have been proposed to ensure good sealing between the internal volume of hydraulic machinery and the external environment. However, known solutions still have problems in terms of reliability, especially reliability over time. The first mounting consists of placing a single axial sealing element that isolates the surrounding environment from the internal volume of the crankcase. If the pressure inside the crankcase rises, the sealing element may be pushed out of the housing, or, in the case of a metal seal, the bearing force between the two sliding parts increases, which can cause the sliding contact surfaces to crack or seize and fail. As a result, in the case of a metal seal, friction increases and efficiency decreases. Such a rise in pressure inside the crankcase occurs, for example, when starting a low-temperature hydraulic machine. Pressurized oil enters the machine's crankcase through internal leaks, which are common in these machines, and the oil in the crankcase cannot easily flow out through the crankcase drain pipe, which is still filled with low-temperature oil. Due to the high viscosity of this low-temperature oil, a very high pressure drop occurs. Such action can cause the sealing element to fail rapidly. In particular, as the pressure inside the machine's crankcase rises, the bearing force between the sliding parts of the sealing element increases, which can cause seizure and the sealing element to fail. Furthermore, the components of the aforementioned sealing element may also be damaged by this pressure. Alternatively, an axial sealing element that isolates the inside and outside of the hydraulic machine may be housed in a dedicated housing. These housings themselves are isolated from the internal volume of the crankcase containing the hydraulic machine by a crankcase seal, generally known as absolute sealing, which combines a dynamic sealing element such as a lip ring with a dynamic sealing element that can withstand the peak pressure that may occur (e.g., an O-ring coupled to an annular element). Such a mounting creates a closed chamber between the axial sealing element and the crankcase sealing element. However, such a closed chamber presents problems in terms of lubrication. In fact, since the housing with the axial sealing element is completely isolated from the internal volume of the crankcase by the crankcase seal, this housing is not continuously lubricated. The lack of lubrication can lead to rapid failure of the axial sealing element, particularly under the influence of heating that can cause seizure due to lack of oil or increase in pressure within the housing, causing oil leakage and further exacerbating the problem. A commonly proposed solution involves inserting a predetermined amount of oil into the housing, which then needs to be replaced periodically. Such solutions are highly restrictive and require specialized maintenance. Furthermore, these solutions present challenges in terms of space requirements for storing sufficient oil within the housing, demanding axial space, which is incompatible with the structure of hydraulic machinery where space constraints are severely limited. This is a cross-sectional view of a part of a hydraulic machine according to one aspect of the present invention.Figure 1 shows a perspective view illustrating an example of a cast core that may be used to form the hydraulic machine shown.This is a partial cross-sectional view showing another example of a hydraulic machine according to one aspect of the present invention. In all diagrams, common elements are given the same symbol. Hereinafter, an exemplary embodiment of the present invention will be described with reference to Figures 1 and 2. Figure 1 shows a partial cross-sectional view of the hydraulic machine 1. The hydraulic machine 1 comprises a first assembly 10 and a second assembly 20 that are rotatable relative to each other along the rotation axis X-X. In the following description, the terms "radial direction" and "axial direction" are defined relative to the rotation axis X-X unless otherwise specified. In the illustrated example, the rotational guide is secured by rolling elements, in this case tapered bearings 32 and 34 forming bearing 30. This exemplary embodiment is not limiting, and it is understood that the rolling elements may be of any type. The hydraulic machine 1 has an internal volume 2 in which different components (e.g., a radial piston hydraulic motor or an axial piston hydraulic motor, a radial piston hydraulic pump or an axial piston hydraulic p