Low-speed rotating joint

Abstract

The low-speed rotating joint comprises a shell and a rotating shaft, an installation cavity is formed in the shell, the rotating shaft is rotatably arranged in the installation cavity, a leading-in channel which is through front and back is formed in the rotating shaft, and a leading-in opening which is communicated with the leading-in channel and used for leading-in of external oil or gas is formed in the shell. The rotary sealing structure is characterized in that a rotary sealing structure is arranged between the outer side wall of the rotating shaft and the inner side wall of the mounting cavity, the rotary sealing structure comprises a hard inner sealing ring and a soft outer sealing ring, the inner sealing ring is arranged outside the rotating shaft in a close fit mode, and the outer sealing ring is arranged outside the inner sealing ring in a close fit mode and tightly attached to the inner side wall of the mounting cavity. The rotary sealing structure has the advantages that the rotary sealing structure is simple, the hard inner sealing ring and the soft outer sealing ring are combined to form the rotary sealing structure, the inner sealing ring is high in hardness and resistant to abrasion, the outer sealing ring is soft and high in elasticity, the outer sealing ring is arranged between the inner sealing ring and the inner side wall of the mounting cavity in a close fit mode and can be used for compensating the abrasion loss of the hard inner sealing ring, and therefore zero leakage is achieved.

Description

Technical Field

[0001] The utility model relates to a rotary joint, in particular to a low-speed rotary joint. Background Art

[0002] A low-speed, small rotary joint is a special type of joint required for small magnetic grinders. Currently, this type of joint consists of three main parts: a housing, a rotating shaft, and a sealing structure. During operation, cutting fluid enters through the oil passage hole in the housing and is output from the rotating shaft to the tool's water jet through the sealing structure. Due to the limited space available for this type of joint in small magnetic grinders, the size of the rotary joint is generally required to be within 30mm in diameter. However, most of these rotary joints currently on the market use mechanical seals (end face seals), which require extremely high sealing surface precision and are difficult to achieve zero leakage. A return pipe connection is usually required for water return, making the rotary joint's size difficult to meet installation requirements. Summary of the Invention

[0003] The technical problem to be solved by the utility model is to provide a low-speed rotary joint with a simple structure, reliable sealing and miniaturized design.

[0004] The technical solution adopted by the present invention to solve the above technical problems is:

[0005] A low-speed rotary joint comprises a shell and a rotating shaft, wherein a mounting cavity for mounting the rotating shaft is provided in the shell, the rotating shaft is rotatably disposed in the mounting cavity and the front end of the rotating shaft extends out of the mounting cavity, an introduction channel is provided in the rotating shaft which passes through the shaft from front to back, and an introduction port for introducing external oil or gas which is connected to the introduction channel is provided on the shell, a rotary sealing structure is provided between the outer wall of the rotating shaft and the inner wall of the mounting cavity, and the rotary sealing structure comprises a hard inner sealing ring and a soft outer sealing ring, the inner sealing ring is tightly fitted on the outside of the rotating shaft, and the outer sealing ring is tightly fitted on the outside of the inner sealing ring and is in close contact with the inner wall of the mounting cavity.

[0006] An annular groove is provided on the inner wall of the inner sealing ring.

[0007] An annular sealing groove is recessed on the inner side wall of the installation cavity, the rotary sealing structure is embedded in the annular sealing groove, and the outer sealing ring is in close contact with the inner side wall of the annular sealing groove.

[0008] The front end face of the inner sealing ring fits with the front inner end face of the annular sealing groove, and the rear end face of the inner sealing ring fits with the rear inner end face of the annular sealing groove.

[0009] The rotating shaft includes an extension section, an installation section and a sealing section arranged in sequence from front to back. The extension section is extended and arranged outside the shell. A bearing for realizing the rotatable installation of the rotating shaft in the shell is arranged between the installation section and the installation cavity. The rotary sealing structure is arranged between the outer wall of the sealing section and the inner wall of the installation cavity.

[0010] The portion of the rotating shaft extending out of the housing is detachably provided with a protective cover.

[0011] Compared with the prior art, the advantages of the present invention are: simple structure, a rotary sealing structure is formed by combining a hard inner sealing ring and a soft outer sealing ring, wherein the inner sealing ring is relatively hard and wear-resistant, while the outer sealing ring is relatively soft and has high elasticity, and is tightly fitted between the inner sealing ring and the inner side wall of the mounting cavity, which can be used to compensate for the wear of the hard inner sealing ring, thereby achieving zero leakage, reliable sealing, and realizing a miniaturized design of the rotary joint. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic cross-sectional view of the utility model;

[0013] Figure 2 for Figure 1 Schematic diagram of the enlarged structure at A in the middle;

[0014] Figure 3 It is a schematic cross-sectional structural diagram of the shell in the present utility model. DETAILED DESCRIPTION

[0015] The present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

[0016] As shown in the figure, a low-speed rotary joint includes a shell 1 and a rotating shaft 2. A mounting cavity 11 for mounting the rotating shaft 2 is provided in the shell 1. The rotating shaft 2 is rotatably disposed in the mounting cavity 11 and the front end of the rotating shaft 2 extends out of the mounting cavity 11. An inlet channel 21 that passes through the rotating shaft 2 is provided in the rotating shaft 2. An inlet 12 connected to the inlet channel 21 for introducing external oil or gas is provided on the shell 1. A rotary sealing structure 3 is provided between the outer wall of the rotating shaft 2 and the inner wall of the mounting cavity 11. The rotary sealing structure 3 includes a hard inner sealing ring 31 and a soft outer sealing ring 32. The inner sealing ring 31 is tightly arranged on the outside of the rotating shaft 2, and the outer sealing ring 32 is tightly arranged on the outside of the inner sealing ring 31 and is in close contact with the inner wall of the mounting cavity 11.

[0017] In this specific embodiment, an annular groove 311 is provided on the inner wall of the inner sealing ring 31. By providing the annular groove 311 on the inner wall of the inner sealing ring 31, a small gap seal is achieved, and a better sealing effect is achieved.

[0018] In this embodiment, an annular sealing groove 111 is recessed into the inner wall of the mounting cavity 11. The rotary sealing structure 3 is embedded in the annular sealing groove 111, and the outer sealing ring 32 is in close contact with the inner wall of the annular sealing groove 111. The annular sealing groove provides a stable mounting position for the rotary sealing structure 3, thereby fixing the mounting position of the sealing structure and further ensuring sealing stability.

[0019] In this specific embodiment, the front end face of the inner sealing ring 31 is in contact with the front inner end face of the annular sealing groove 111, and the rear end face of the inner sealing ring 31 is in contact with the rear inner end face of the annular sealing groove 111. A further seal is formed on the front and rear end faces, further ensuring the sealing effect.

[0020] In this embodiment, the rotating shaft 2 includes, from front to back, an extension section 201, a mounting section 202, and a sealing section 203. The extension section 201 extends from the exterior of the housing 1. A bearing 4 is disposed between the mounting section 202 and the mounting cavity 11, allowing the rotating shaft 2 to be rotatably mounted within the housing 1. The rotating seal structure 3 is disposed between the outer wall of the sealing section 203 and the inner wall of the mounting cavity 11. The extension section 201 extends out of the mounting cavity 11 to connect with other external components; the mounting section 202 is used to mount the bearing 4, allowing the rotating shaft 2 to be rotatably mounted within the mounting cavity 11; and the sealing section 203 is used to mount the rotating seal structure 3, providing internal sealing.

[0021] In this embodiment, the portion of the rotating shaft 2 extending outside the housing 1 is detachably provided with a protective cover 5. When not in use, the protective cover 5 can protect the portion of the rotating shaft 2 extending outside.

Claims

1. A low-speed rotary joint, comprising a housing and a rotating shaft, wherein the housing is provided with a mounting cavity for mounting the rotating shaft, the rotating shaft is rotatably disposed in the mounting cavity and the front end of the rotating shaft extends out of the mounting cavity, the rotating shaft is provided with a front-to-back through-channel, and the housing is provided with an inlet for introducing external oil or gas, the inlet being connected to the inlet channel. A rotary sealing structure is provided between the outer wall of the rotating shaft and the inner wall of the mounting cavity. The rotary sealing structure includes a hard inner sealing ring and a soft outer sealing ring. The inner sealing ring is tightly arranged on the outside of the rotating shaft, and the outer sealing ring is tightly arranged on the outside of the inner sealing ring and is in close contact with the inner wall of the mounting cavity.

2. A low-speed rotary joint according to claim 1, characterized in that An annular groove is provided on the inner wall of the inner sealing ring.

3. A low-speed rotary joint according to claim 1, characterized in that An annular sealing groove is recessed on the inner side wall of the installation cavity, the rotary sealing structure is embedded in the annular sealing groove, and the outer sealing ring is in close contact with the inner side wall of the annular sealing groove.

4. A low-speed rotary joint according to claim 3, characterized in that The front end face of the inner sealing ring fits with the front inner end face of the annular sealing groove, and the rear end face of the inner sealing ring fits with the rear inner end face of the annular sealing groove.

5. A low-speed rotary joint according to claim 1, characterized in that The rotating shaft includes an extension section, an installation section and a sealing section arranged in sequence from front to back. The extension section is extended and arranged outside the shell. A bearing for realizing the rotatable installation of the rotating shaft in the shell is arranged between the installation section and the installation cavity. The rotary sealing structure is arranged between the outer wall of the sealing section and the inner wall of the installation cavity.

6. A low-speed rotary joint according to claim 1, characterized in that The portion of the rotating shaft extending out of the housing is detachably provided with a protective cover.

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