Swivel joint for fire fighting truck

Abstract

The invention discloses a swivel joint for a fire fighting truck, and relates to the technical field of fire fighting equipment. Comprising a rotary shell, the inner wall of the rotary shell is rotatably connected with a rotary shaft assembly, the outer wall, away from the rotary shaft assembly, of the rotary shell is fixedly connected with an electric slip ring, the inner wall of the lower portion of the connecting base is in through connection with the outer wall of the rotary shell, the inner wall of the rotary shell is fixedly connected with an oil separator sealing ring, and the oil separator sealing ring is fixedly connected with the rotary shaft assembly. A gasket is fixedly connected to the inner wall, close to the electric slip ring, of the rotary shell, an O-shaped ring is attached between the gasket and the electric slip ring, and an oil groove is formed in the inner wall, away from the electric slip ring, of the rotary shell. The multi-channel annular arrangement is adopted, the main channel and the branch channels are independently isolated, and the guiding effect of the oil groove is matched, so that split-flow conveying of media needed by multiple executing mechanisms can be achieved, meanwhile, the sealing cover can block impurities, and smoothness of the channels and conveying independence are guaranteed.

Description

Technical Field

[0001] This invention relates to the field of fire-fighting equipment technology, specifically to a rotary joint for fire trucks. Background Technology

[0002] In firefighting operations, key components of fire trucks, such as ladders and rotating platforms, need to be able to rotate flexibly to cover a wider range of operations and accurately respond to fires in different locations. As the core hydraulic or pneumatic transmission component that connects fixed pipelines to rotating components, the performance of the rotary joint directly determines the stability of the medium transmission in key circuits such as the fire truck's hydraulic system and cooling system. It is a fundamental core component that ensures the accurate and reliable execution of actions such as ladder lifting, platform rotation, and fire spraying.

[0003] For example, Chinese patent CN105221154B discloses a rotary joint for a tunnel boring machine, which includes a small rotary joint (29), a rotor, a stator, a sealing assembly and a rotating support. The stator is sleeved outside the input end of the rotor. The sealing assembly and the rotating support are arranged between the stator and the rotor. The small rotary joint (29) is connected to the input end of the rotor. The stator includes a housing (28), a connecting seat (9), a retaining ring (14) and a bolt (15). The connecting seat (9) is fixed to the front of the housing (28) by the bolt (15), and the retaining ring (14) is fixed to the front of the connecting seat (9) by the bolt (15).

[0004] While the above solutions have the advantages mentioned above, their disadvantages are as follows: since fire trucks need to coordinate the control of multiple independent actions simultaneously during operation, the rotary joint must have multiple independent media transmission channels to provide hydraulic oil, coolant and other media to different actuators. Furthermore, strict isolation must be achieved between the channels to avoid cross-contamination or mixing of liquids, which could cause interference with the operation. Summary of the Invention

[0005] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a rotary joint for fire trucks, which solves the problem of having multiple independent media transmission channels.

[0006] (II) Technical Solution To achieve the above objectives, the present invention provides the following technical solution: a rotary joint for fire trucks, comprising a rotary housing, a rotary shaft assembly rotatably connected to the inner wall of the rotary housing, and an electric slip ring fixedly connected to the outer wall of the rotary housing away from the rotary shaft assembly. It further comprises a connecting seat, the inner wall below the connecting seat being in continuous connection with the outer wall of the rotary housing. An oil distributor sealing ring is fixedly connected to the inner wall of the rotary housing, and a gasket is fixedly connected to the inner wall of the rotary housing near the electric slip ring. An O-ring is fitted between the gasket and the electric slip ring. The oil distributor sealing ring, gasket, and O-ring serve to seal and prevent leakage, avoiding side leakage when the rotary shaft assembly and the rotary housing rotate. An oil groove is formed on the inner wall of the rotary housing away from the electric slip ring. A central groove is formed in the middle of the inner wall of the rotary shaft assembly. A first through groove and a second through groove are also formed inside the rotary shaft assembly, and the first through groove and the second through groove are interconnected through a first oil distribution port. The first oil distributor port is located on the central shaft of the rotary shaft assembly. The rotary shaft assembly has a connecting port on its outer wall inside the oil tank. The multi-stage sealing structure, which coordinates the oil distributor sealing ring, gasket, and O-ring, improves sealing reliability compared to a single sealing structure, prevents media leakage, and ensures the sealing stability of the rotary joint under high pressure and high frequency braking conditions, avoiding operational failures caused by leakage. The oil tank can temporarily store and guide the flow of the medium, reduce the resistance to medium flow, and ensure smooth medium transmission. The first oil distributor port is located in the central shaft area, which makes the medium distribution more uniform and improves the stability of medium transmission, adapting to the medium transmission needs of complex fire truck operation scenarios. The connection seat provides a convenient and stable connection structure for the assembly of the rotary joint and external components, improving the overall assembly efficiency and structural integrity, and ensuring that the rotary joint will not affect the working stability due to loose assembly during operation.

[0007] Preferably, the connecting port is interconnected with the first through groove, the second through groove, and the first oil distribution port, while the first through groove, the second through groove, and the center groove are not interconnected. The inner wall of the oil distributor sealing ring is rotatably connected to the outer wall of the rotary shaft assembly located inside the rotary housing. The gasket abuts against the outer wall of the rotary shaft assembly near the slip ring. The interconnection of the connecting port with the first through groove, the second through groove, and the first oil distribution port ensures the integrity and smoothness of the medium transmission channel, reduces resistance and stagnation during medium transmission, and effectively prevents medium crossflow between different channels, ensuring the independence and stability of each channel's function, avoiding malfunction of the actuator due to crossflow, and improving the operational reliability of the rotary joint. The rotational sealing cooperation between the oil distributor sealing ring and the rotary shaft assembly, as well as the abutting cooperation between the gasket and the rotary shaft assembly, further enhances the overall sealing performance, ensuring flexible rotation of the rotary shaft assembly while improving the leak-proof effect and extending the service life of the rotary joint.

[0008] Preferably, the rotary shaft assembly has a third through groove on its inner wall near the first through groove, and a second oil distribution port communicating with the third through groove is provided on the outer wall of the rotary shaft assembly outside the rotary housing. The addition of the third through groove and the second oil distribution port expands the number of media transmission channels of the rotary joint, enabling the rotary joint to simultaneously adapt to the media supply needs of multiple actuators, improving the adaptability and functionality of the rotary joint, and meeting the needs of multi-action coordinated operation of fire trucks. The second oil distribution port is located outside the rotary housing, which facilitates assembly and connection with external pipelines, reduces the difficulty of pipeline assembly, and improves assembly efficiency. At the same time, the independent channel can ensure the stability of media transmission within the channel and avoid interference with other channels.

[0009] Preferably, the rotary shaft assembly has a fourth through groove on its inner wall near the third through groove, and the rotary shaft assembly has a third oil outlet on its outer wall near the second oil outlet on the outside of the rotary housing. The fourth through groove and the third oil outlet are interconnected. The arrangement of the fourth through groove and the third oil outlet further increases the independent medium transmission channel of the rotary joint, enabling the rotary joint to meet the collaborative operation needs of more actuators, improving the flexibility and versatility of fire truck operation. The third oil outlet is located near the second oil outlet, which facilitates the centralized arrangement and organization of external pipelines, reduces pipeline clutter, and lowers the difficulty of subsequent pipeline maintenance. At the same time, the independent channel ensures the stability and accuracy of medium transmission and improves the reliability of the actuator's operation.

[0010] Preferably, the inner wall of the rotary shaft assembly near the fourth through groove has a fifth through groove, and the outer wall of the rotary shaft assembly outside the rotary housing has a fourth oil outlet that communicates with the fifth through groove. The addition of the fifth through groove and the fourth oil outlet continuously expands the number of media transmission channels of the rotary joint, further improving the adaptability of the rotary joint to the coordinated operation of multiple actuators of the fire truck, meeting the needs of more complex fire operation scenarios. The independent channel ensures the stability and independence of the media transmission, avoids cross-flow or interference with the media of other channels, ensures the accuracy and reliability of the corresponding actuator's action, and improves the overall operational safety.

[0011] Preferably, the inner wall of the rotary shaft assembly, near the fifth through slot and away from the fourth through slot, has a sixth through slot. The outer wall of the rotary shaft assembly, located outside the rotary housing, has a fifth oil outlet that communicates with the sixth through slot. The arrangement of the sixth through slot and the fifth oil outlet further enriches the media transmission channels of the rotary joint, enabling the rotary joint to adapt to the more diverse actuator requirements of fire trucks, and improving the overall functionality and applicability of the equipment. The sixth through slot is located in an area far from the fourth through slot, which can effectively avoid structural interference and media interference with adjacent channels, ensuring the independence and stability of each channel's operation. At the same time, the connection between the external pipeline and the fifth oil outlet is convenient, facilitating assembly and maintenance.

[0012] Preferably, the inner wall of the rotary shaft assembly, near the sixth through groove and away from the fifth through groove, has a seventh through groove. The outer wall of the rotary shaft assembly, located outside the rotary housing, has a sixth oil outlet that communicates with the seventh through groove. The addition of the seventh through groove and the sixth oil outlet further improves the multi-channel media transmission system of the rotary joint, enabling the rotary joint to fully adapt to the media requirements of various actuators of fire trucks and improve the coordination of fire truck operations. The seventh through groove is located away from the fifth through groove, ensuring the independence between channels and avoiding media crossflow and structural interference. The setting of the sixth oil outlet facilitates the connection and maintenance of external pipelines and reduces equipment operation and maintenance costs.

[0013] Preferably, the interior of the rotary shaft assembly is arranged in a ring around the central groove, with the first through groove, second through groove, third through groove, second oil outlet, fourth through groove, third oil outlet, fifth through groove, fourth oil outlet, sixth through groove, fifth oil outlet, seventh through groove, and sixth oil outlet all having sealing caps on their inner walls. The third through groove, central groove, fourth through groove, fifth through groove, sixth through groove, and seventh through groove inside the rotary shaft assembly are not interconnected. This ring arrangement around the central groove maximizes... By utilizing the internal space of the rotary shaft assembly and rationally planning the positions of each channel, structural interference is avoided. This reduces processing difficulty, improves processing efficiency and product qualification rate. The mutual isolation between each channel ensures the independence of media transmission in each channel from a structural perspective, completely avoiding cross-flow phenomenon and ensuring that each actuator can receive the corresponding media supply. This improves the reliability and stability of the overall operation. The comprehensive setting of the sealing cover not only prevents media leakage in the channel but also blocks the entry of external impurities, providing a dual protection function. This extends the service life of the rotary joint, reduces maintenance costs, and ensures the stable operation of the rotary joint in harsh firefighting environments.

[0014] (III) Beneficial Effects This invention provides a rotary joint for fire trucks. It has the following beneficial effects: (i) The rotary joint for this fire truck adopts a multi-channel ring arrangement, with the main channel and each branch channel being independently isolated. With the guidance of the oil tank, it can realize the diversion and transmission of the medium required by multiple actuators. At the same time, the sealing cover can block impurities and ensure smooth channels and independent transmission.

[0015] (ii) The rotary joint of this fire truck, through the synergistic effect of the multi-stage sealing structure composed of the oil distributor sealing ring, gasket and O-ring, can prevent media leakage, avoid operational failure caused by side leakage and extend the service life of the equipment.

[0016] (iii) The rotary joint of the fire truck, through the through-type assembly structure of the connecting seat, facilitates the connection between the rotary joint and external components and pipelines, ensures the stability of the overall structure, reduces loosening caused by operational vibration, and reduces the difficulty of assembly and subsequent maintenance.

[0017] (iv) The rotary joint of the fire truck forms a collaborative operation system through the stable rotational cooperation between the rotary shaft assembly and the rotary housing, the continuous signal transmission of the electric slip ring, the supply of multi-channel media and the continuous protection of multi-level sealing, so as to ensure that during the operation of the fire truck, each actuator can act according to the control command and the electrical signal interaction is smooth and uninterrupted. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the structure of the explosion of the present invention; Figure 3 This is a cross-sectional view of the present invention; Figure 4 This is a schematic diagram of the structure of the first through groove of the present invention; Figure 5 This is a schematic diagram of the structure of the third through groove of the present invention; Figure 6 This is a schematic diagram of the structure of the fourth through groove of the present invention; Figure 7 This is a schematic diagram of the structure of the fifth through groove of the present invention; Figure 8 This is a schematic diagram of the structure of the sixth through groove of the present invention; Figure 9 This is a schematic diagram of the structure of the seventh through groove of the present invention.

[0019] In the diagram: 1. Rotary shaft assembly; 2. Rotary housing; 3. Oil distributor sealing ring; 4. Gasket; 5. O-ring; 6. Slip ring; 7. Oil groove; 8. Connecting seat; 9. First oil distributor port; 10. First through groove; 11. Second through groove; 12. Third through groove; 13. Second oil distributor port; 14. Center groove; 15. Sealing cover; 16. Fourth through groove; 17. Third oil distributor port; 18. Fifth through groove; 19. Fourth oil distributor port; 20. Sixth through groove; 21. Fifth oil distributor port; 22. Seventh through groove; 23. Sixth oil distributor port; 24. Connecting port. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Please see Figures 1-9 This invention provides a technical solution: a rotary joint for fire trucks, including a rotary housing 2, a rotary shaft assembly 1 rotatably connected to the inner wall of the rotary housing 2, and an electric slip ring 6 fixedly connected to the outer wall of the rotary housing 2 away from the rotary shaft assembly 1. It also includes a connecting seat 8, the inner wall below the connecting seat 8 being in communication with the outer wall of the rotary housing 2, a distributor sealing ring 3 fixedly connected to the inner wall of the rotary housing 2, and a gasket 4 fixedly connected to the inner wall of the rotary housing 2 near the electric slip ring 6. An O-ring 5 is fitted between the gasket 4 and the electric slip ring 6. The O-ring 5 serves to seal and prevent leakage, avoiding side leakage when the rotary shaft assembly 1 and the rotary housing 2 rotate. The inner wall of the rotary housing 2 away from the slip ring 6 has an oil groove 7. The inner wall of the rotary shaft assembly 1 has a central groove 14. The rotary shaft assembly 1 also has a first through groove 10 and a second through groove 11. The first through groove 10 and the second through groove 11 are interconnected by a first oil distribution port 9. The first oil distribution port 9 is located on the central shaft of the rotary shaft assembly 1. The outer wall of the rotary shaft assembly 1 located inside the oil groove 7 has a connecting port 24.

[0022] The connecting port 24 is interconnected with the first through groove 10, the second through groove 11 and the first oil distribution port 9. The first through groove 10, the second through groove 11 and the center groove 14 are not interconnected. The inner wall of the oil distributor sealing ring 3 is rotatably connected to the outer wall of the rotary shaft assembly 1 located inside the rotary housing 2. The gasket 4 abuts against the outer wall of the rotary shaft assembly 1 near the electric slip ring 6.

[0023] The inner wall of the rotary shaft assembly 1 near the first through groove 10 has a third through groove 12, and the outer wall of the rotary shaft assembly 1 located outside the rotary housing 2 has a second oil outlet 13 that communicates with the third through groove 12.

[0024] The inner wall of the rotary shaft assembly 1 near the third through groove 12 has a fourth through groove 16, and the outer wall of the rotary shaft assembly 1 near the second oil outlet 13 has a third oil outlet 17. The fourth through groove 16 and the third oil outlet 17 are interconnected.

[0025] The inner wall of the rotary shaft assembly 1 near the fourth through groove 16 has a fifth through groove 18, and the outer wall of the rotary shaft assembly 1 located outside the rotary housing 2 has a fourth oil outlet 19 that communicates with the fifth through groove 18.

[0026] The inner wall of the rotary shaft assembly 1, near the fifth through groove 18 and away from the fourth through groove 16, has a sixth through groove 20. The outer wall of the rotary shaft assembly 1, located outside the rotary housing 2, has a fifth oil outlet 21 that communicates with the sixth through groove 20.

[0027] The inner wall of the rotary shaft assembly 1, near the sixth through groove 20 and away from the fifth through groove 18, has a seventh through groove 22. The outer wall of the rotary shaft assembly 1, located outside the rotary housing 2, has a sixth oil outlet 23 that communicates with the seventh through groove 22.

[0028] The interior of the rotary shaft assembly 1 is arranged in a ring around the central groove 14, with the first through groove 10, the second through groove 11, the third through groove 12, the second oil outlet 13, the fourth through groove 16, the third oil outlet 17, the fifth through groove 18, the fourth oil outlet 19, the sixth through groove 20, the fifth oil outlet 21, the seventh through groove 22, and the sixth oil outlet 23. The inner walls of the first through groove 10, the second through groove 11, the third through groove 12, the second oil outlet 13, the fourth through groove 16, the third oil outlet 17, the fifth through groove 18, the fourth oil outlet 19, the sixth through groove 20, the fifth oil outlet 21, the seventh through groove 22, and the sixth oil outlet 23 are all sealed with sealing caps 15. The third through groove 12, the central groove 14, the fourth through groove 16, the fifth through groove 18, the sixth through groove 20, and the seventh through groove 22 inside the rotary shaft assembly 1 are not interconnected.

[0029] In use, the rotating housing 2 serves as the core mounting base, and its inner wall forms a rotatable fit with the rotating shaft assembly 1, ensuring that the rotating shaft assembly 1 can rotate stably around its own axis, providing a basis for the rotational movement of the fire truck's working parts. The connecting seat 8 is fixedly assembled to the outer wall of the rotating housing 2 through a through-type connection structure, which not only realizes the stable connection between the rotary joint and other external parts of the fire truck, ensuring the integrity of the overall structure, but also provides a convenient assembly benchmark for the docking of external pipelines and the rotary joint. At the same time, an electric slip ring 6 is fixedly assembled on the outer wall of the rotating housing 2 away from the rotating shaft assembly 1, which prepares the structure for the continuous and stable transmission of electrical signals during subsequent rotation.

[0030] This stage is the core working stage of the rotary joint, realizing the diversion and stable transmission of multi-channel media. The specific flow path can be divided into two parts: main channel flow and branch channel flow. First, in the main channel, the external medium enters the oil groove 7 on the inner wall of the rotary housing 2 away from the slip ring 6 through the corresponding pipeline. The oil groove 7 temporarily stores and guides the flow of the entering medium, reducing the resistance to medium flow. Subsequently, the medium in the oil groove 7 enters the rotary shaft through the communication port 24 located on the inner outer wall of the oil groove 7 in the rotary shaft assembly 1. The internal channel of component 1 is interconnected with the first through slot 10, the second through slot 11 and the first oil distribution port 9 through the connecting port 24. After the medium enters through the connecting port 24, it can be evenly distributed between the first through slot 10 and the second through slot 11 through the first oil distribution port 9 to complete the medium distribution of the main channel. It is worth noting that the first through slot 10 and the second through slot 11 are isolated from the central slot 14 in the middle of the inner wall of the rotary shaft component 1 to prevent cross-flow between the main channel medium and the central slot 14 area, thus ensuring the independence of the main channel medium transmission.

[0031] Secondly, regarding the flow of media in the branch channels, to meet the collaborative operation requirements of multiple actuators on the fire truck, multiple branch channels are arranged in a ring around the central groove 14 inside the rotary shaft assembly 1. Each branch channel independently completes the transmission of a specific medium. Specifically, the third groove 12, which is close to the first groove 10, connects to the external pipeline through the second oil distribution port 13 to achieve independent transmission of one branch medium. The fourth groove 16, which is close to the third groove 12, connects to the external pipeline through the third oil distribution port 17 to complete the transmission of another branch medium. Subsequently, the fifth groove 18 connects to the fourth oil distribution port 19... The sixth channel 20 and the fifth oil outlet 21, and the seventh channel 22 and the sixth oil outlet 23 are sequentially matched to form multiple independent branch media transmission channels. Each branch channel is isolated from the main channel, the central channel 14 and other branch channels. The medium is transmitted to different actuators of the fire truck through the corresponding channel and oil outlet, providing a stable medium supply for the independent operation of each actuator. In addition, the sealing cover 15 installed on the inner wall of each channel and oil outlet can effectively prevent external impurities from entering the channel, avoid channel blockage and affect the flow of medium, and ensure the smoothness of medium transmission.

[0032] This process utilizes a multi-stage sealing structure to prevent media leakage and ensure the stability and safety of media transmission. The distributor seal ring 3, gasket 4, and O-ring 5, fixedly mounted inside the rotary housing 2, form a multi-stage sealing protection system. The inner wall of the distributor seal ring 3 and the outer wall of the rotary shaft assembly 1 located inside the rotary housing 2 form a rotational seal fit. Without affecting the normal rotation of the rotary shaft assembly 1, this prevents media leakage from the gap between the rotary shaft assembly 1 and the rotary housing 2. The gasket 4 is installed on the inner wall of the rotary housing 2 near the slip ring 6, and it tightly abuts against the outer wall of the rotary shaft assembly 1 near the slip ring 6, forming an auxiliary sealing barrier. The O-ring 5 is tightly fitted between the gasket 4 and the slip ring 6, further enhancing the sealing effect and preventing media leakage from the connection between the slip ring 6 and the rotary housing 2. This multi-stage sealing structure can meet the sealing requirements under high pressure and high frequency rotation conditions, avoid operational failures caused by media side leakage, and extend the service life of the rotary joint.

[0033] During actual fire truck operations, the components of the rotary joint work in a coordinated manner. The rotary shaft assembly 1 rotates synchronously around its own axis along with the fire truck's operating components such as the ladder and rotary platform. During this process, the electric slip ring 6 works synchronously to achieve continuous and stable transmission of electrical signals during rotation, ensuring smooth interaction between control signals and feedback signals. The multi-channel media transmission system continuously provides accurate and stable media supply to each actuator, ensuring that each actuator can complete the corresponding actions according to the control commands. The multi-level sealing structure always maintains a sealed state to prevent media leakage. The connecting seat 8 ensures the stability of the connection between the rotary joint and external components, preventing loosening of the assembly due to operational vibration. The coordinated cooperation of all components enables the rotary joint to stably adapt to the complex operating scenarios of the fire truck, ensuring the efficiency and safety of the fire truck operation.

[0034] In summary, the rotary joint for fire trucks, through its complete working logic from basic assembly to media transmission and flow, sealing and protection, and then multi-component collaborative operation, achieves independent transmission of multiple media channels and stable transmission of electrical signals during rotation. At the same time, reliable sealing and protection prevent leakage, providing core assurance for the stable operation of various working components of the fire truck.

[0035] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0036] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A rotary joint for fire trucks, comprising a rotary housing (2), wherein a rotary shaft assembly (1) is rotatably connected to the inner wall of the rotary housing (2), and an electric slip ring (6) is fixedly connected to the outer wall of the rotary housing (2) away from the rotary shaft assembly (1), characterized in that, It also includes: a connecting seat (8), the inner wall of the connecting seat (8) is connected to the outer wall of the rotary housing (2), the inner wall of the rotary housing (2) is fixedly connected with an oil separator sealing ring (3), the inner wall of the rotary housing (2) near the electric slip ring (6) is fixedly connected with a gasket (4), and an O-ring (5) is attached between the gasket (4) and the electric slip ring (6). The oil separator sealing ring (3), gasket (4), and O-ring (5) play a role in sealing and preventing leakage, so as to avoid side leakage when the rotary shaft assembly (1) and the rotary housing (2) rotate. An oil groove (7) is opened on the inner wall of the rotary housing (2) away from the electric slip ring (6). The inner wall of the rotary shaft assembly (1) has a central groove (14) and a first through groove (10) and a second through groove (11) are also provided inside the rotary shaft assembly (1). The first through groove (10) and the second through groove (11) are interconnected by a first oil distribution port (9). The first oil distribution port (9) is located on the central shaft of the rotary shaft assembly (1). The outer wall of the rotary shaft assembly (1) located inside the oil tank (7) has a connecting port (24).

2. The rotary joint for fire trucks according to claim 1, characterized in that: The connecting port (24) is interconnected with the first through groove (10), the second through groove (11) and the first oil distribution port (9). The first through groove (10), the second through groove (11) and the center groove (14) are not interconnected. The inner wall of the oil distributor sealing ring (3) is rotatably connected to the outer wall of the rotary shaft assembly (1) located inside the rotary housing (2). The gasket (4) is in contact with the outer wall of the rotary shaft assembly (1) near the electric slip ring (6).

3. The rotary joint for fire trucks according to claim 1, characterized in that: The rotary shaft assembly (1) has a third through groove (12) on its inner wall near the first through groove (10), and the rotary shaft assembly (1) has a second oil outlet (13) on its outer wall outside the rotary housing (2) that communicates with the third through groove (12).

4. The rotary joint for fire trucks according to claim 1, characterized in that: The rotary shaft assembly (1) has a fourth through groove (16) on its inner wall near the third through groove (12), and the rotary shaft assembly (1) has a third oil outlet (17) on its outer wall near the second oil outlet (13) outside the rotary housing (2). The fourth through groove (16) and the third oil outlet (17) are interconnected.

5. The rotary joint for fire trucks according to claim 1, characterized in that: The rotary shaft assembly (1) has a fifth through groove (18) on its inner wall near the fourth through groove (16), and the rotary shaft assembly (1) has a fourth oil outlet (19) on its outer wall outside the rotary housing (2) that communicates with the fifth through groove (18).

6. The rotary joint for fire trucks according to claim 1, characterized in that: The inner wall of the rotary shaft assembly (1) near the fifth through groove (18) and away from the fourth through groove (16) has a sixth through groove (20), and the outer wall of the rotary shaft assembly (1) located outside the rotary housing (2) has a fifth oil outlet (21) that communicates with the sixth through groove (20).

7. The rotary joint for fire trucks according to claim 6, characterized in that: The inner wall of the rotary shaft assembly (1) near the sixth through groove (20) and away from the fifth through groove (18) has a seventh through groove (22), and the outer wall of the rotary shaft assembly (1) located outside the rotary housing (2) has a sixth oil outlet (23) that communicates with the seventh through groove (22).

8. The rotary joint for fire trucks according to claim 2, characterized in that: The rotary shaft assembly (1) has the following internal components arranged in a ring around the central groove (14): first through groove (10), second through groove (11), third through groove (12), second oil outlet (13), fourth through groove (16), third oil outlet (17), fifth through groove (18), fourth oil outlet (19), sixth through groove (20), fifth oil outlet (21), seventh through groove (22), and sixth oil outlet (23). The first through groove (10), second through groove (11), third through groove (12), and seventh through groove (23) are arranged in a ring around the central groove (14). The inner walls of the three-way groove (12), the second oil outlet (13), the fourth groove (16), the third oil outlet (17), the fifth groove (18), the fourth oil outlet (19), the sixth groove (20), the fifth oil outlet (21), the seventh groove (22), and the sixth oil outlet (23) are all filled with sealing caps (15). The third groove (12), the center groove (14), the fourth groove (16), the fifth groove (18), the sixth groove (20), and the seventh groove (22) inside the rotary shaft assembly (1) are not interconnected.

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