Air cushion sealing element and sealing structure thereof

Abstract

The invention discloses an air cushion sealing piece and a sealing structure thereof. The air cushion sealing piece comprises a sealing inner lip, a vent groove is formed in the sealing contact face of the sealing inner lip and penetrates to the near-air end of the sealing inner lip, a pump pressure groove communicated with the vent groove is formed in the sealing contact face of the sealing inner lip, and the pump pressure groove is arranged in the circumferential direction and is of a wedge-shaped structure. The sealing structure comprises a rotating component and further comprises the air cushion sealing piece, and the sealing contact face of the sealing inner lip is in sealing fit with the rotating component. The sealing element has the beneficial effects that based on the pneumatic principle of the wedge-shaped pump pressure groove, gas generates a wedge-shaped effect at the pump pressure groove during high-speed rotation, so that an air cushion is formed between a rotating component and the sealing inner lip, the friction loss between the sealing element and the rotating component is reduced, and the long-term dynamic sealing effect of the sealing element under the high-speed working condition is ensured.

Description

Technical Field

[0001] The present application belongs to the technical field of rotary seals, and in particular relates to an air cushion seal and a sealing structure thereof. Background Art

[0002] Seals, also called oil seals, are materials or parts that prevent fluids or solid particles from leaking from adjacent mating surfaces and prevent external impurities such as dust and moisture from invading parts inside machinery and equipment. They are widely used in the lubricating oil sealing of shafts. In traditional seals, due to the high-speed rotation of the shaft, the contact between the shaft and the seal will inevitably cause wear, and the long-term dynamic sealing effect cannot be guaranteed, affecting the service life and sealing quality. Summary of the invention

[0003] The purpose of the present application is to provide an air cushion seal and a sealing structure thereof, which solves the problem of long-term dynamic sealing of the seal under high-speed rotation conditions.

[0004] The purpose of this application is achieved through the following technical solutions:

[0005] An air cushion seal comprises an inner sealing lip, a sealing contact surface of the inner sealing lip being provided with a ventilation groove, the ventilation groove extending to the air-proximal end of the inner sealing lip, and a sealing contact surface of the inner sealing lip being provided with a pump pressure groove connected to the ventilation groove, the pump pressure groove being arranged along the circumferential direction and having a wedge-shaped structure.

[0006] Furthermore, it also includes a fixed outer frame and an elastic waist, the fixed outer frame is connected to the outer end of the elastic waist, and the inner end of the elastic waist is connected to the sealing inner lip.

[0007] Furthermore, the fixed external frame is an L-shaped cross-sectional structure, one section of the L-shaped fixed external frame is connected to the elastic waist, the other section of the L-shaped fixed external frame faces the same side as the elastic waist, the elastic waist is arranged at an angle, and the sealing inner lip is arranged in the same direction as the other section of the L-shaped fixed external frame.

[0008] Furthermore, the fixed external frame includes an axial section and a radial section, the air-proximal end of the axial section is connected to the outer end of the radial section, the inner end of the radial section is connected to the elastic waist, an L-shaped support frame is embedded in the axial section and the radial section, and a fixed contact surface of the axial section is provided with a fixed flange.

[0009] Furthermore, the elastic waist includes an oblique waist section, the outer end of the oblique waist section is connected to the fixed outer frame through a gas-proximal angle head, and the inner end of the oblique waist section is connected to the sealing inner lip through a liquid-proximal elbow.

[0010] Furthermore, there are a plurality of ventilation grooves, which are arranged on the sealing inner lip at intervals along the circumferential direction, and each ventilation groove is connected to a plurality of pump pressure grooves.

[0011] Furthermore, the pump pressure groove includes a main pump pressure groove and an auxiliary pump pressure groove, the groove length of the main pump pressure groove is greater than the groove length of the auxiliary pump pressure groove, the main pump pressure groove is arranged in the forward rotation direction of the sealing inner lip, and the auxiliary pump pressure groove is arranged in the reverse rotation direction of the sealing inner lip.

[0012] Furthermore, the pump pressure groove includes a flat bottom edge, an inclined side edge and an inclined top edge forming a wedge-shaped structure, the flat bottom edge is parallel to the circumferential direction of the sealing inner lip, an angle α is formed between the inclined side edge and the flat bottom edge, an angle β is formed between the inclined top edge and the flat bottom edge, α is 10°~15°, β is 2°~10°, and the groove depth of the pump pressure groove is h, h is 0.01mm~0.05mm.

[0013] A sealing structure of an air cushion seal includes a rotating component and the above-mentioned air cushion seal, wherein the sealing contact surface of the sealing inner lip forms a sealing match with the rotating component, the liquid-proximal end of the sealing inner lip is close to the liquid side, and the gas-proximal end of the sealing inner lip is close to the gas side.

[0014] A sealing structure of an air cushion seal includes a fixed component and a rotating component, and also includes the above-mentioned air cushion seal, wherein the fixed contact surface of the fixed outer frame is connected to the fixed component, the sealing contact surface of the sealing inner lip forms a sealing match with the rotating component, the liquid-proximal end of the sealing inner lip is close to the liquid side, and the gas-proximal end of the sealing inner lip is close to the gas side.

[0015] Beneficial effects of this application:

[0016] (1) Based on the pneumatic principle of the wedge-shaped pump pressure groove, the gas produces a wedge effect at the pump pressure groove during high-speed rotation, thereby forming an air cushion between the rotating component and the inner lip of the seal, reducing the friction loss between the seal and the rotating component, and ensuring the long-term dynamic sealing effect of the seal under high-speed conditions.

[0017] (2) The elastic waist is used to provide elastic force for the inner lip of the seal. Even if the inner lip of the seal is worn out due to friction, the inner lip of the seal can still perform self-compensation under the action of the elastic force, thereby ensuring the sealing effect of the inner lip of the seal on the rotating component.

[0018] (3) The pump pressure groove includes a main groove in the forward rotation direction and an auxiliary groove in the reverse rotation direction. Under most forward rotation conditions, the main groove continuously ensures the sealing of components under high-speed rotation. Under a small number of reverse rotation conditions, the auxiliary groove can maintain the sealing of components under reduced speed rotation for a period of time, thus meeting various sealing requirements.

[0019] The aforementioned main scheme of the present application and its further options can be freely combined to form multiple schemes, all of which are schemes that can be adopted and claimed for protection in the present application; and in the present application, (non-conflicting options) can also be freely combined with each other and with other options. After understanding the scheme of the present application, those skilled in the art can understand that there are many combinations based on the prior art and common knowledge, all of which are technical schemes to be protected by the present application, and they are not exhaustively listed here. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of the sealing member of the present application.

[0021] Figure 2 It is a structural schematic diagram of the sealing structure of the present application.

[0022] In the figure: 1-fixed outer frame, 2-elastic waist, 3-sealing inner lip, 101-axial section, 102-radial section, 103-support frame, 104-fixed flange, 201-near gas angle head, 202-inclined waist section, 203-near liquid elbow, 302-venting groove, 303-main pump pressure groove, 304-auxiliary pump pressure groove, 305-weir area, 306-dam area; 100-fixed component, 200-rotating component, 10-liquid side, 20-gas side. DETAILED DESCRIPTION

[0023] The following non-limiting examples are provided to illustrate the present application.

[0024] Example 1

[0025] refer to Figure 1 As shown, an air cushion seal comprises a fixed outer frame 1, an elastic waist 2 and a sealing inner lip 3, wherein the fixed outer frame 1 is connected to the outer end of the elastic waist 2, and the inner end of the elastic waist 2 is connected to the sealing inner lip 3.

[0026] The fixed outer frame 1 is used to connect and fix the seal to the fixed component, the elastic waist 2 is used for the transition between the outer frame and the inner lip and provides elastic force for the inner lip, and the sealing inner lip 3 is used to cooperate with the rotating component to perform a specific sealing function.

[0027] The fixed outer frame 1 is an L-shaped cross-sectional structure, one section (radial section) of the L-shape of the fixed outer frame 1 is connected to the outer end of the elastic waist 2, and the other section (axial section) of the L-shape of the fixed outer frame 1 is used to achieve fixation on the fixed component.

[0028] The other L-shaped section of the fixed outer frame 1 faces the same side (liquid side) as the elastic waist 2, and the elastic waist 2 is arranged at an angle. This structure is relatively simple, ensuring that the fixed outer frame 1 achieves the fixing function, while ensuring that the elastic waist 2 achieves the elastic transition function, and the outer frame and the waist do not occupy too much axial and radial space, so that it can be used in a small space.

[0029] The elastic waist 2 provides elastic force for the sealing inner lip 3. Even if the sealing inner lip 3 is worn out due to friction, the sealing inner lip can also compensate itself under the action of the elastic force to ensure the sealing effect of the sealing inner lip on the rotating component. The sealing inner lip 3 is arranged in the same direction (axially) as the other section of the L-shape of the fixed outer frame 1, and the sealing inner lip 3 is used to directly realize the sealing effect on the outer peripheral surface of the shaft body, thereby reducing the space volume of the entire sealing component.

[0030] The fixed outer frame 1 includes an axial section 101, a radial section 102, a support frame 103 and a fixed flange 104, wherein except for the support frame 103 which is preferably made of metal, the rest are preferably made of rubber. The gas-proximal end (gas-proximal means close to the gas, the same below) of the axial section 101 is vertically connected to the outer end of the radial section 102 to form an L-shaped cross-sectional structure, and the inner end of the radial section 102 is connected to the elastic waist 2.

[0031] An L-shaped support frame 103 is embedded in the axial section 101 and the radial section 102 to support and stabilize the structure of the external frame. Preferably, the support frame 103 is exposed on the inner circumference of the axial section 101 and the near liquid surface of the radial section 102 (near liquid means close to the liquid, the same below). The fixed contact surface of the axial section 101, that is, the outer circumference, is integrally provided with a fixing flange 104 to facilitate the fixing operation of the external frame.

[0032] The elastic waist 2 includes an air-proximal angle head 201, an oblique waist section 202 and a liquid-proximal elbow 203 of an integral structure, all of which are preferably made of rubber. The outer end of the oblique waist section 202 is integrally connected to the radial section 102 of the fixed outer frame 1 through the air-proximal angle head 201, realizing the transition from the thicker radial section 102 to the thinner oblique waist section 202. The inner end of the oblique waist section 202 is integrally connected to the outer peripheral surface of the sealing inner lip 3 through the liquid-proximal elbow 203, realizing the bending transition from the oblique waist section 202 to the axial sealing inner lip 3.

[0033] The sealing inner lip 3 is made of rubber and includes an outer circumferential surface and an inner circumferential surface. The sealing contact surface of the sealing inner lip 3, i.e., the inner circumferential surface, is provided with a vent groove 302 and a pumping groove. The vent groove 302 passes through the proximal end of the sealing inner lip 3, so that the air on the gas side can enter the vent groove 302. The sealing contact surface of the sealing inner lip 3 is provided with a pumping groove connected to the vent groove 302, and the pumping groove is used to form an air cushion when the rotating component rotates.

[0034] The pumping grooves are arranged along the circumference and have a wedge-shaped structure. When rotating at high speed, the gas generates a wedge effect at the pumping grooves, that is, the gas enters the pumping grooves through the ventilation grooves 302, and the rotating components drive the gas to move. The gas flows into the wedge-shaped convergence gap of the pumping grooves to generate pressurized gas, thereby forming an air cushion between the rotating components and the inner lip of the seal, reducing the friction loss between the seal and the rotating components.

[0035] There are a number of ventilation grooves 302, which are arranged in the axial direction, and a number of ventilation grooves 302 are arranged at intervals in the circumferential direction on the sealing inner lip 3, and each ventilation groove 302 is connected to a number of pumping grooves, so that the pumping grooves are evenly distributed on the sealing contact surface, ensuring the balanced support of the sealing element to the rotating component. For example, the ventilation grooves 302 are arranged in multiple rows, and the pumping grooves are arranged in multiple layers.

[0036] Since the vent groove 302 does not penetrate to the liquid-proximal end of the sealing inner lip 3, a weir area 305 is formed on the sealing contact surface of the sealing inner lip 3 at the liquid-proximal end to block the gas entering the vent groove 302, generating air pressure to form an air cushion effect. The area between two adjacent vent grooves and the pump pressure groove on the sealing contact surface of the sealing inner lip 3 is a weir area 306.

[0037] The pump pressure groove includes a main pump pressure groove 303 and an auxiliary pump pressure groove 304. The groove length (arc length) of the main pump pressure groove 303 is greater than the groove length (arc length) of the auxiliary pump pressure groove 304. The main pump pressure groove 303 is arranged toward the positive rotation direction of the sealing inner lip 3 (i.e., the direction of positive rotation of the rotating component), and the auxiliary pump pressure groove 304 is arranged toward the reverse rotation direction of the sealing inner lip 3 (i.e., the direction of reverse rotation of the rotating component).

[0038] The rotating components include forward high-speed rotation conditions with a maximum speed of 30,000 rpm and reverse speed reduction conditions within 10,000 rpm (based on the forward speed reduction). Under most forward rotation conditions, a wedge effect is generated in the main pump pressure groove 303 to continuously ensure the sealing of the components under high-speed rotation. Under a small part of the reverse rotation conditions, a wedge effect is generated in the auxiliary pump pressure groove 304 to maintain the sealing of the components under speed reduction for a period of time.

[0039] The pump pressure groove (the main pump pressure groove 303 and the auxiliary pump pressure groove 304) includes a flat bottom edge, an inclined side edge and an inclined top edge forming a wedge-shaped structure. The flat bottom edge is parallel to the circumferential direction of the sealing inner lip 3, and an angle α is formed between the inclined side edge and the flat bottom edge, and an angle β is formed between the inclined top edge and the flat bottom edge. α is 10°~15°, and β is 2°~10°. The groove depth of the pump pressure groove (the main pump pressure groove 303 and the auxiliary pump pressure groove 304) is h, and h is 0.01mm~0.05mm, so that a good aerodynamic effect can be formed to ensure the stability and reliability of the air cushion.

[0040] Example 2

[0041] refer to Figure 1 and Figure 2 As shown, a sealing structure of an air cushion seal includes a rotating component 200 and the air cushion seal of Example 1. The sealing contact surface (inner circumference) of the sealing inner lip 3 forms a sealing match with the rotating component 200 (shaft body), the liquid-proximal end of the sealing inner lip 3 is close to the liquid side 10, and the gas-proximal end of the sealing inner lip 3 is close to the gas side 20.

[0042] Under sealing conditions, the gas (air) on the gas side enters the pump pressure groove from the ventilation groove, and the wedge effect of the fluid forms a pressurized gas, which generates a certain air cushion between the rotating component (shaft body) and the inner lip of the seal, thereby reducing the friction between the inner lip of the seal and the rotating component (shaft body). At the same time, the pump pressure groove can pump the sealed liquid (lubricant) back to the liquid side. Since the pumping capacity of the main pump pressure groove is greater than that of the auxiliary pump pressure groove, long-term dynamic sealing can be achieved at a maximum speed of 30,000 rpm. When the rotating component (shaft body) rotates in the reverse direction, the speed is low, and the fluid film thickness is small at this time. Due to the pumping effect of the auxiliary pump pressure groove, the liquid (lubricant) can be maintained within a speed of 10,000 rpm for a period of time without leakage.

[0043] Example 3

[0044] refer to Figure 1 and Figure 2 As shown, a sealing structure of an air cushion seal includes a fixed component 100 and a rotating component 200, and also includes the air cushion seal of Example 1. The fixed contact surface (outer peripheral surface) of the fixed outer frame 1 is fixedly connected to the fixed component 100, the sealing contact surface (inner peripheral surface) of the sealing inner lip 3 forms a sealing match with the rotating component 200, the liquid-proximal end of the sealing inner lip 3 is close to the liquid side 10, and the gas-proximal end of the sealing inner lip 3 is close to the gas side 20.

[0045] The working process of this embodiment is the same as that of embodiment 2, and the fixed outer frame 1 supports the elastic waist 2 at the same time. The elastic waist 2 exerts an elastic force on the sealing inner lip 3, and the sealing inner lip can perform self-compensation under the action of the elastic force.

[0046] The aforementioned basic examples and their further selected examples can be freely combined to form multiple embodiments, all of which are embodiments that can be adopted and claimed for protection in this application. In the scheme of this application, each selected example can be arbitrarily combined with any other basic examples and selected examples.

[0047] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. An air cushion seal, comprising a sealing inner lip (3), characterized in that: The sealing contact surface of the sealing inner lip (3) is provided with a ventilation groove (302), the ventilation groove (302) passes through to the proximal end of the sealing inner lip (3), and the sealing contact surface of the sealing inner lip (3) is provided with a pump pressure groove connected to the ventilation groove (302), and the pump pressure groove is arranged along the circumferential direction and has a wedge-shaped structure.

2. The air cushion seal according to claim 1, characterized in that: It also comprises a fixed outer frame (1) and an elastic waist (2), wherein the fixed outer frame (1) is connected to the outer end of the elastic waist (2), and the inner end of the elastic waist (2) is connected to the sealing inner lip (3).

3. The air cushion seal according to claim 2, characterized in that: The fixed outer frame (1) is an L-shaped cross-sectional structure, one section of the L-shaped fixed outer frame (1) is connected to the elastic waist (2), the other section of the L-shaped fixed outer frame (1) faces the same side as the elastic waist (2), the elastic waist (2) is arranged at an angle, and the sealing inner lip (3) is arranged in the same direction as the other section of the L-shaped fixed outer frame (1).

4. The air cushion seal according to claim 2 or 3, characterized in that: The fixed outer frame (1) comprises an axial section (101) and a radial section (102); the air-proximal end of the axial section (101) is connected to the outer end of the radial section (102); the inner end of the radial section (102) is connected to the elastic waist (2); an L-shaped support frame (103) is embedded in the axial section (101) and the radial section (102); and a fixed flange (104) is provided on the fixed contact surface of the axial section (101).

5. The air cushion seal according to claim 2 or 3, characterized in that: The elastic waist (2) comprises an oblique waist section (202), the outer end of the oblique waist section (202) is connected to the fixed outer frame (1) through a proximal air angle head (201), and the inner end of the oblique waist section (202) is connected to the sealing inner lip (3) through a proximal liquid elbow (203).

6. The air cushion seal according to claim 1, 2 or 3, characterized in that: There are a plurality of ventilation grooves (302), which are arranged on the sealing inner lip (3) at intervals along the circumferential direction, and each ventilation groove (302) is connected to a plurality of pump pressure grooves.

7. The air cushion seal according to claim 1, 2 or 3, characterized in that: The pump pressure groove comprises a main pump pressure groove (303) and an auxiliary pump pressure groove (304); the groove length of the main pump pressure groove (303) is greater than the groove length of the auxiliary pump pressure groove (304); the main pump pressure groove (303) is arranged in the forward direction of the sealing inner lip (3), and the auxiliary pump pressure groove (304) is arranged in the reverse direction of the sealing inner lip (3).

8. The air cushion seal according to claim 1, 2 or 3, characterized in that: The pump pressure groove comprises a flat bottom edge, an inclined side edge and an inclined top edge forming a wedge-shaped structure, the flat bottom edge is parallel to the circumferential direction of the sealing inner lip (3), an angle α is formed between the inclined side edge and the flat bottom edge, an angle β is formed between the inclined top edge and the flat bottom edge, α is 10° to 15°, β is 2° to 10°, and the groove depth of the pump pressure groove is h, which is 0.01mm to 0.05mm.

9. A sealing structure of an air cushion seal, comprising a rotating member (200), characterized in that: It also includes the air cushion seal described in any one of claims 1 to 8, the sealing contact surface of the sealing inner lip (3) forms a sealing fit with the rotating component (200), the liquid-proximal end of the sealing inner lip (3) is close to the liquid side (10), and the gas-proximal end of the sealing inner lip (3) is close to the gas side (20).

10. A sealing structure of an air cushion seal, comprising a fixed component (100) and a rotating component (200), characterized in that: It also includes the air cushion seal described in any one of claims 2 to 8, the fixed contact surface of the fixed outer frame (1) is connected to the fixed component (100), the sealing contact surface of the sealing inner lip (3) forms a sealing fit with the rotating component (200), the liquid-proximal end of the sealing inner lip (3) is close to the liquid side (10), and the gas-proximal end of the sealing inner lip (3) is close to the gas side (20).

Images