High pressure hydraulic swivel

Abstract

The application relates to the technical field of fluid transmission and sealing, in particular to a high-pressure hydraulic rotary joint which comprises a fixed outer shell, a rotatable central rotating shaft and a dynamic compensation sealing assembly arranged between the outer shell and the central rotating shaft. The outer shell is internally provided with a containing chamber and a pressure guiding channel, the dynamic compensation sealing assembly comprises a sealing bearing ring, a main sealing element, a pressure compensation component and a damping component, the pressure compensation component applies an axial thrust to the sealing bearing ring through fluid pressure, and the damping component is arranged between the sealing bearing ring and the containing chamber. The application can realize stable and reliable sealing performance under a high-pressure environment.

Description

Technical Field

[0001] This utility model belongs to the field of fluid transmission and sealing technology, specifically a high-pressure hydraulic rotary joint. Background Technology

[0002] High-pressure hydraulic rotary joints are mechanical connection devices used to achieve continuous high-pressure fluid transmission between fixed pipelines and rotating equipment. They are widely used in engineering machinery, metallurgical equipment, wind power equipment, and marine systems, where hydraulic power transmission is required while the equipment is rotating. These joints typically consist of a housing, shaft, sealing components, bearings, and lubrication structures. They can withstand high working pressures while adapting to certain speeds and swing angles, achieving stable hydraulic oil delivery.

[0003] Key performance indicators for high-pressure hydraulic rotary joints include sealing reliability, pressure resistance, service life, and stability under dynamic operating conditions. In practical applications, they typically need to meet requirements for long-term operation, low leakage, contamination resistance, and good load-bearing capacity. As industrial equipment develops towards higher power density and higher integration, higher demands are placed on the adaptability of rotary joints under complex operating conditions.

[0004] However, most existing high-pressure hydraulic rotary joints adopt a structure that combines end face sealing and radial sealing. They maintain the sealing interface fit through pre-tightening force to achieve the sealing effect. However, during long-term operation, the contact pressure of the sealing interface may change due to factors such as pressure fluctuations, temperature changes and mechanical vibrations, resulting in fluctuations in sealing performance. Under the condition of high speed and high pressure at the same time, there is room for further improvement in the existing structure in maintaining stable sealing. Utility Model Content

[0005] This utility model provides a high-pressure hydraulic rotary joint, which aims to solve the technical problem in the prior art where the contact pressure at the sealing interface changes due to pressure fluctuations, temperature changes and mechanical vibrations, resulting in fluctuations in sealing performance.

[0006] To achieve the above objectives, this utility model provides the following technical solution: A high-pressure hydraulic rotary joint includes a fixed outer housing, a central rotating shaft rotatable within the outer housing, and a dynamic compensation sealing assembly disposed between the outer housing and the central rotating shaft, wherein: The outer shell has an annular receiving chamber on its inner peripheral wall, and a pressure guiding channel connecting the internal fluid channel of the central rotating shaft with the receiving chamber.

[0007] The central rotating shaft passes through the outer casing, and a dynamic sealing surface is formed on the outer peripheral wall of the central rotating shaft to cooperate with the dynamic compensation sealing assembly.

[0008] The dynamic compensation sealing assembly is slidably disposed within the receiving cavity. The dynamic compensation sealing assembly includes a sealing support ring, a main seal, a pressure compensation component, and a vibration damping component. The sealing support ring is slidably mounted within the receiving cavity along the axial direction of the central rotating shaft. The main seal is mounted on the sealing support ring and contacts the dynamic sealing surface of the central rotating shaft. The pressure compensation component acts on the end of the sealing support ring opposite to the main seal, applying an axial thrust related to the fluid pressure by means of the fluid pressure entering the receiving cavity via the pressure guiding channel. The vibration damping component is disposed between the sealing support ring and the inner wall of the receiving cavity.

[0009] Optionally, the pressure compensation assembly includes a pre-tightening elastic element and a pressure application surface. The pre-tightening elastic element is disposed between the bottom of the receiving chamber and the sealing bearing ring to provide initial sealing force for the main seal. The pressure application surface is the end face of the sealing bearing ring facing away from the main seal, and the outlet of the pressure guiding channel faces the pressure application surface, through which hydraulic fluid applies dynamic compensation pressure to the sealing bearing ring.

[0010] Optionally, the pre-tightening elastic element is a wave spring assembly, which is composed of multiple wave spring plates stacked together. An adjusting shim for adjusting the pre-tightening force of the wave spring assembly is also fixed on the outer shell, and the adjusting shim is located at the bottom of the receiving chamber.

[0011] Optionally, the vibration damping assembly includes an annular vibration damping strip and a mounting groove disposed on the outer peripheral wall of the sealing bearing ring. The vibration damping strip is fixed in the mounting groove, and the outer surface of the vibration damping strip is in contact with the inner peripheral wall of the receiving chamber. The vibration damping strip is made of damping rubber material.

[0012] Optionally, the dynamic compensation sealing assembly further includes a secondary seal, which is installed in the housing and located outside the main seal. The sealing lip of the secondary seal is in contact with the dynamic seal of the central rotating shaft to prevent external impurities from entering.

[0013] Optionally, the outer shell is formed by screwing together a main shell, a front end cover, and a rear end cover. The receiving chamber is formed by the inner hole of the main shell and the front end cover. The rear end cover is used to close the receiving chamber and axially limit the pre-tightening elastic element.

[0014] Optionally, the central rotating shaft is supported in the housing by two sets of angular contact ball bearings, a bearing isolation sleeve is provided between the two sets of angular contact ball bearings, and an isolation sealing ring is provided between the mounting area of ​​the angular contact ball bearing and the receiving chamber to separate the hydraulic fluid from the bearing grease.

[0015] Optionally, the main seal is a combined sealing ring, which includes a wear-resistant ring made of polytetrafluoroethylene and an O-ring rubber energy storage ring. The sliding surface of the wear-resistant ring contacts the dynamic sealing surface of the central rotating shaft, and the O-ring rubber energy storage ring provides radial tension to the wear-resistant ring.

[0016] Optionally, the sealing bearing ring has a stepped cross-section, with its inner ring used to install the main seal and its outer ring used to install the vibration damping component. Several guide grooves are also machined on the outer peripheral wall of the sealing bearing ring, which cooperate with the inner wall of the receiving chamber to limit the axial sliding trajectory of the sealing bearing ring.

[0017] This utility model provides a high-pressure hydraulic rotary joint, which has the following beneficial effects: This high-pressure hydraulic rotary joint, through the design of a dynamic compensation sealing assembly, particularly the pressure compensation component, introduces high-pressure fluid into the receiving chamber via a pressure guiding channel. This fluid acts directly on the pressure-acting surface of the sealing bearing ring, and the resulting axial thrust is directly related to the system fluid pressure. When the system pressure fluctuates, the sealing force applied to the main seal is adjusted accordingly, thereby dynamically maintaining a constant contact pressure at the sealing interface and significantly improving sealing reliability under high pressure and pressure fluctuation conditions. The vibration damping component, using damping inserts to form a flexible support between the sealing bearing ring and the outer shell, absorbs mechanical vibration from the central rotating shaft, reducing the interference of vibration on the fit between the main seal and the dynamic sealing surface, further consolidating sealing stability at high speeds. The configuration of the pre-tightening elastic element ensures that the main seal still has basic sealing force during system startup or under low pressure, achieving effective sealing across the entire pressure range. Attached Figure Description

[0018] Figure 1 This is a cross-sectional schematic diagram of the overall structure of the high-pressure hydraulic rotary joint of this utility model; Figure 2 This is a partially enlarged structural schematic diagram of the dynamic compensation sealing assembly according to an embodiment of this application; Figure 3 This is a schematic diagram of the assembly structure of the sealing bearing ring and vibration damping component of this utility model; Figure 4 This is a schematic diagram of the central rotating shaft and bearing support structure according to an embodiment of this application; Explanation of reference numerals in the attached figures: 1. Outer shell; 2. Central pivot; 3. Dynamic compensation seal assembly; 4. Receiving chamber; 5. Pressure guide channel; 6. Sealing bearing ring; 7. Main seal; 8. Pressure compensation assembly; 9. Vibration damping assembly; 10. Preload elastic element; 11. Pressure application surface; 12. Adjusting shim; 13. Vibration damping insert; 14. Mounting groove; 15. Secondary seal; 16. Front cover; 17. Rear cover; 18. Angular contact ball bearing. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0020] Please see Figures 1 to 4 This utility model provides a high-pressure hydraulic rotary joint, which is applied in industrial equipment that requires the transmission of high-pressure hydraulic fluid between stationary and rotating components, such as the slewing platform of construction machinery, the pitch system of wind turbine generators, or the rotary joint of industrial robots. The high-pressure hydraulic rotary joint provided in this embodiment, through a specific design of its internal structure, enables dynamic adjustment of the contact pressure at the sealing interface under complex working conditions such as drastic pressure fluctuations, high temperature changes, and mechanical vibrations, thereby achieving continuously stable sealing performance.

[0021] Please see Figure 1 This utility model provides a technical solution: a high-pressure hydraulic rotary joint, whose overall structure mainly includes a fixed outer shell 1, a central rotating shaft 2 that can rotate freely inside the outer shell 1, and a dynamic compensation sealing assembly 3 disposed between the outer shell 1 and the central rotating shaft 2, performing the core sealing function. The outer shell 1 serves as the stationary base of the rotary joint, with one end connected to an external fixed pipeline and the other end housing and supporting the central rotating shaft 2. The central rotating shaft 2, as a rotating component, has a fluid channel inside, with one end connected to an external rotating equipment pipeline. During rotation, high-pressure hydraulic fluid flows through the rotary joint via the internal fluid channel of the central rotating shaft 2. The dynamic compensation sealing assembly 3 is installed inside the outer shell 1 and forms a dynamic sealing fit with the outer peripheral wall of the central rotating shaft 2. Its structural design is the key to achieving dynamic pressure compensation and vibration reduction sealing in this utility model.

[0022] Please see Figure 1 and Figure 4The structure of the outer casing 1 is described in detail below. The outer casing 1 is a modular structure, consisting of a main casing, a front cover 16, and a rear cover 17, which are fastened together with bolts. This modular design reduces the difficulty of overall manufacturing and provides access for the installation and maintenance of internal components. The main casing has a precision-machined inner bore, a portion of which, together with the inner end face of the front cover 16, forms an annular receiving chamber 4. This receiving chamber 4 is the installation space for the dynamic compensation sealing assembly 3, and its dimensional accuracy directly affects the motion guidance and positioning of the sealing assembly. One or more pressure guiding channels 5 are also machined on the outer casing 1. One end of the pressure guiding channel 5 is connected to the fluid channel inside the central rotating shaft 2, and the outlet of the other end opens into the inner wall of the receiving chamber 4, specifically facing the pressure-bearing surface of a specific component in the dynamic compensation sealing assembly 3. A portion of the high-pressure hydraulic fluid is introduced into the receiving chamber 4 through this pressure guiding channel 5, providing a power source for subsequent pressure compensation actions. The rear end cover 17 is installed at the other end of the main housing. Its main function is to close the receiving chamber 4 and provide axial positioning and support for the pre-tightening elastic element 10 in the dynamic compensation sealing assembly 3.

[0023] Please see Figure 1 and Figure 4 The structure and support method of the central rotating shaft 2 are described in detail. The central rotating shaft 2 is a precision-machined shaft part that runs through the central hole of the outer casing 1. On the outer peripheral wall of the central rotating shaft 2, corresponding to the position of the dynamic compensation seal assembly 3, there is a section of dynamic sealing surface that has been precision ground or polished. This dynamic sealing surface has extremely low surface roughness and high hardness, and is the mating surface for the main seal 7 to achieve reliable dynamic sealing. To ensure stable rotation of the central rotating shaft 2 under high pressure and high speed conditions, it is supported inside the outer casing 1 by two sets of angular contact ball bearings 18. These two sets of angular contact ball bearings 18 are installed back-to-back or face-to-face to simultaneously bear radial loads and bidirectional axial loads. Between the two sets of angular contact ball bearings 18, a bearing isolation sleeve is provided. This isolation sleeve precisely controls the distance between the two sets of bearings, thereby setting the bearing preload and ensuring rotational accuracy and rigidity. An isolation seal is installed between the mounting area of ​​the angular contact ball bearing 18 and the housing chamber 4. This isolation seal effectively separates the high-pressure hydraulic fluid in the housing chamber 4 from the lubricating grease in the bearing mounting area, thus avoiding cross-contamination between the two.

[0024] Please see Figure 1 , Figure 2 and Figure 3The structure of the core part of this utility model, namely the dynamic compensation sealing assembly 3, will be described in detail below. The dynamic compensation sealing assembly 3 is slidably installed in the aforementioned receiving chamber 4, and its components include a sealing bearing ring 6, a main sealing element 7, a pressure compensation component 8, and a vibration damping component 9.

[0025] The sealing support ring 6 is the skeleton component of the dynamic compensation sealing assembly 3, and its cross-sectional shape is stepped. This stepped structure forms a mounting groove in the inner ring, where the main seal 7 is installed. Its outer ring has mounting grooves 14 for mounting the vibration damping component 9. Several axially distributed guide grooves are also machined on the outer peripheral wall of the sealing support ring 6. These guide grooves cooperate with the inner wall of the receiving chamber 4, forming a fluid lubrication channel between them and limiting the sealing support ring 6 to precise reciprocating sliding only along the axial direction of the central shaft 2, without radial wobble or circumferential rotation. The sealing support ring 6 is made of a metal material with sufficient strength and wear resistance, such as bronze or stainless steel.

[0026] The main seal 7 is the core component performing the dynamic sealing function, and it is installed in the mounting groove of the inner ring of the sealing support ring 6. In this embodiment, the main seal 7 adopts a combined sealing ring structure, which includes a wear-resistant ring made of polytetrafluoroethylene (PTFE) and an O-ring rubber accumulator. The sliding surface of the wear-resistant ring directly contacts the dynamic sealing surface of the central rotating shaft 2, forming the main sealing surface. The PTFE filling material has an extremely low coefficient of friction and excellent wear resistance, high pressure resistance, and chemical corrosion resistance. The O-ring rubber accumulator is installed inside the wear-resistant ring, and its own elastic deformation provides a continuous radial tension to the wear-resistant ring, so that the sliding surface of the wear-resistant ring is always tightly fitted to the dynamic sealing surface of the central rotating shaft 2, maintaining basic sealing contact even at low system pressures.

[0027] The pressure compensation component 8 is a key structure for dynamically adjusting the sealing force. This component includes a pre-tightening elastic element 10 disposed between the bottom of the receiving chamber 4 and the sealing support ring 6, and a pressure-acting surface 11 formed by the end face of the sealing support ring 6 facing away from the main seal 7. In this embodiment, the pre-tightening elastic element 10 is preferably a set of wave springs, which is composed of multiple stacked wave spring plates. Compared to traditional helical springs, wave spring sets can provide greater elastic force within the same installation space, and the elastic force characteristics are more linear. The wave spring set is compressed during assembly, providing an initial axial pre-tightening force to the sealing support ring 6. This pre-tightening force is transmitted to the main seal 7 through the sealing support ring 6, thus ensuring an effective initial seal between the main seal 7 and the dynamic sealing surface even during system startup or in zero-pressure or low-pressure states. To precisely adjust the magnitude of this initial pre-tightening force, an adjusting shim 12 is also fixed on the outer casing 1. This adjusting shim 12 is located at the bottom of the receiving chamber 4. By increasing or decreasing the number or thickness of the adjusting shims 12, the initial compression of the wave spring set can be changed, thereby precisely setting the initial sealing force. The pressure-acting surface 11 is the rear end face of the sealing bearing ring 6, and the outlet of the aforementioned pressure guiding channel 5 is directly opposite the pressure-acting surface 11. When the high-pressure fluid enters the receiving chamber 4 through the pressure guiding channel 5, it will directly act on the pressure-acting surface 11, generating an axial thrust proportional to the fluid pressure.

[0028] The vibration damping component 9 functions to absorb and attenuate mechanical vibrations. This component includes an annular damping strip 13 and a mounting groove 14 formed on the outer peripheral wall of the sealing bearing ring 6. The damping strip 13 is made of a rubber material with high damping characteristics, such as nitrile rubber or fluororubber. The damping strip 13 is fixed in the mounting groove 14 by an interference fit, and its outer surface is tightly fitted against the inner peripheral wall of the receiving chamber 4. Thus, a flexible support and connection layer is formed between the rigid sealing bearing ring 6 and the rigid outer shell 1. When the central rotating shaft 2 experiences mechanical vibration due to factors such as imbalance or load changes, this vibration is transmitted to the sealing bearing ring 6 through the main seal 7. The damping characteristics of the damping strip 13 effectively absorb and dissipate this vibration energy, reducing the interference of vibration on the contact state between the main seal 7 and the dynamic sealing surface.

[0029] Please refer to it again. Figure 1 and Figure 2This invention also includes a secondary seal 15. The secondary seal 15 is installed inside the front cover 16 of the housing 1 and is located outside the main seal 7, that is, closer to the external environment of the rotary joint. The secondary seal 15 can be a lip seal ring, whose sealing lip also contacts the dynamic sealing surface of the central rotating shaft 2. The main function of the secondary seal 15 is to act as a dust barrier, preventing external dust, moisture, and other impurities from intruding into the working area of ​​the main seal 7, thus providing a clean working environment for the main seal 7.

[0030] The working process of this high-pressure hydraulic rotary joint is as follows: When the assembly is complete and the system is not pressurized, the pre-tightened elastic element 10 in the pressure compensation component 8, i.e. the wave spring group, is in a pre-compressed state. Its elastic force is applied to the main seal 7 through the sealing bearing ring 6, so that the wear-resistant ring of the main seal 7 is tightly attached to the dynamic sealing surface of the central rotating shaft 2 with a preset contact pressure, forming an initial seal.

[0031] When high-pressure hydraulic fluid begins to flow through the internal fluid channel of the central rotating shaft 2, a portion of the fluid enters the receiving chamber 4 via the pressure guide channel 5. This high-pressure fluid acts directly on the pressure-acting surface 11 of the sealing bearing ring 6, generating a powerful axial thrust. This thrust, combined with the elastic force of the pre-tightened elastic element 10, acts together on the sealing bearing ring 6, thereby significantly increasing the contact pressure between the main seal 7 and the dynamic sealing surface, achieving reliable sealing under high pressure.

[0032] During operation, if the system pressure fluctuates, for example, if the pressure rises from a high pressure P1 to a higher pressure P2, the pressure of the fluid entering the receiving chamber 4 will also rise synchronously to P2. The axial thrust acting on the pressure-acting surface 11 will increase accordingly, and the sealing bearing ring 6 will experience a greater thrust, further tightening the main seal 7. The contact pressure will also increase accordingly to accommodate the higher system pressure. Conversely, if the system pressure drops from P2 to P1, the axial thrust acting on the pressure-acting surface 11 will decrease accordingly, and the contact pressure on the main seal 7 will also decrease accordingly. This process occurs in real time and automatically, and the sealing force always maintains a dynamic and positively correlated matching relationship with the system pressure, thereby maintaining a relatively constant contact pressure at the sealing interface.

[0033] Meanwhile, during the high-speed rotation of the central shaft 2, any mechanical vibrations that may occur will be absorbed and attenuated by the damping strips 13 in the damping assembly 9 after being transmitted to the sealing bearing ring 6. The vibrations will not seriously affect the microscopic fit between the main seal 7 and the dynamic sealing surface, thus maintaining the stability of the seal. The secondary seal 15 continuously blocks external contaminants, extending the service life of the main seal 7.

[0034] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A high-pressure hydraulic rotary joint, characterized in that: It includes a fixed outer shell (1), a central rotating shaft (2) rotatable within the outer shell (1), and a dynamic compensation sealing assembly (3) disposed between the outer shell (1) and the central rotating shaft (2), wherein: The outer shell (1) has an annular receiving chamber (4) on its inner peripheral wall, and the outer shell (1) also has a pressure guiding channel (5) that connects the internal fluid channel of the central rotating shaft (2) with the receiving chamber (4). The central rotating shaft (2) passes through the outer shell (1), and a dynamic sealing surface that cooperates with the dynamic compensation sealing assembly (3) is formed on the outer peripheral wall of the central rotating shaft (2). The dynamic compensation sealing assembly (3) is slidably disposed in the receiving chamber (4). The dynamic compensation sealing assembly (3) includes a sealing bearing ring (6), a main seal (7), a pressure compensation component (8), and a vibration damping component (9). The sealing bearing ring (6) is slidably mounted in the receiving chamber (4) along the axial direction of the central rotating shaft (2). The main seal (7) is mounted on the sealing bearing ring (6) and contacts the dynamic sealing surface of the central rotating shaft (2). The pressure compensation component (8) acts on the end of the sealing bearing ring (6) away from the main seal (7), and the fluid pressure entering the receiving chamber (4) through the pressure guiding channel (5) applies an axial thrust to the sealing bearing ring (6). The vibration damping component (9) is disposed between the sealing bearing ring (6) and the inner wall of the receiving chamber (4).

2. The high-pressure hydraulic rotary joint according to claim 1, characterized in that: The pressure compensation component (8) includes a pre-tightening elastic element (10) and a pressure application surface (11). The pre-tightening elastic element (10) is disposed between the bottom of the receiving chamber (4) and the sealing bearing ring (6). The pressure application surface (11) is the end face of the sealing bearing ring (6) facing away from the main seal (7). The outlet of the pressure guiding channel (5) is directly opposite the pressure application surface (11).

3. The high-pressure hydraulic rotary joint according to claim 2, characterized in that: The pre-tightening elastic element (10) is a wave spring assembly, and an adjusting shim (12) for adjusting the pre-tightening force of the wave spring assembly is also fixed on the outer shell (1). The adjusting shim (12) is located at the bottom of the receiving chamber (4).

4. The high-pressure hydraulic rotary joint according to claim 1, characterized in that: The vibration damping assembly (9) includes an annular vibration damping strip (13) and a mounting groove (14) disposed on the outer peripheral wall of the sealing bearing ring (6). The vibration damping strip (13) is fixed in the mounting groove (14). The outer surface of the vibration damping strip (13) is in contact with the inner peripheral wall of the receiving chamber (4). The vibration damping strip (13) is made of damping rubber material.

5. The high-pressure hydraulic rotary joint according to claim 1, characterized in that: It also includes a secondary seal (15), which is installed inside the housing (1) and located outside the main seal (7), and the sealing lip of the secondary seal (15) is in contact with the dynamic sealing surface of the central rotating shaft (2).

6. The high-pressure hydraulic rotary joint according to claim 2, characterized in that: The outer shell (1) is formed by screwing together a main shell, a front cover (16) and a rear cover (17). The receiving chamber (4) is formed by the inner hole of the main shell and the front cover (16). The rear cover (17) closes the receiving chamber (4) and axially limits the pre-tightening elastic element (10).

7. The high-pressure hydraulic rotary joint according to claim 1, characterized in that: The central rotating shaft (2) is supported in the outer shell (1) by two sets of angular contact ball bearings (18). A bearing isolation sleeve is provided between the two sets of angular contact ball bearings (18). An isolation sealing ring is provided between the mounting area of ​​the angular contact ball bearings (18) and the receiving chamber (4).

8. The high-pressure hydraulic rotary joint according to claim 1, characterized in that: The main seal (7) is a combined sealing ring, which includes a wear-resistant ring made of polytetrafluoroethylene and an O-ring rubber energy storage ring. The sliding surface of the wear-resistant ring is in contact with the dynamic sealing surface of the central rotating shaft (2), and the O-ring rubber energy storage ring provides radial tension to the wear-resistant ring.

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