Rotary seal structure of a hollow cup motor
By introducing a two-stage sealing mechanism of dust-throwing ring groove and spiral groove into the hollow cup motor, the problem of contaminants entering the motor is solved, achieving high-efficiency sealing performance, long service life, and low cost improvement.
Patent Information
- Application Number
- CN202522117359.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-30
- Publication Date
- 2026-08-25
- Estimated Expiration
- 2035-09-30
AI Technical Summary
During the rotation of a coreless motor, contaminants (such as dust, moisture, oil mist, etc.) can easily enter the motor through the gap between the spindle and the motor body, leading to a decrease in motor performance or failure. Existing sealing methods suffer from severe wear or insufficient sealing capacity during high-speed rotation.
A two-stage sealing mechanism is adopted, including a dust-throwing ring groove and a spiral groove. The dust-throwing ring groove throws out larger particles and liquids through centrifugal force, while the spiral groove handles fine contaminants through cyclone effect. Combined with the wear-resistant bushing and the main shaft, a stable radial clearance is formed to reduce wear.
It significantly improves the sealing performance of the motor, effectively prevents contaminants from entering, and extends the service life of the motor. In particular, it can still operate normally in humid or liquid environments, with minimal increase in cost.
Smart Images
Figure CN224683993U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of hollow cup motor technology, and in particular to a rotary sealing structure for a hollow cup motor. Background Technology
[0002] Coreless motors, a type of micro-motor characterized by high efficiency, high response speed, and excellent control characteristics, are named for their coreless, cup-shaped rotor structure and are widely used in high-tech fields such as aerospace, precision instruments, robotics, and medical equipment. However, while their unique "hollow" rotor structure brings performance advantages, it also poses a more severe challenge to the motor's sealing and protection. The dynamic gap between the motor's rotating shaft and the stationary body is the main pathway for external contaminants (such as dust, moisture, oil mist, salt spray, and even metal debris and lubricating grease from the processing) to enter the motor's interior.
[0003] Once contaminants enter the motor through this gap, it can cause a series of serious problems: dust accumulation may lead to uneven air gaps between the rotor and stator, increasing running resistance, causing vibration and noise, and even jamming; the intrusion of moisture or liquid can corrode the delicate winding coils, leading to decreased insulation performance, causing short circuits, and motor failure. Especially in harsh working conditions such as food processing, chemical industry, outdoor operations, and underwater equipment, the requirements for the sealing reliability of motors are extremely high.
[0004] Currently, common motor shaft sealing methods mainly include contact seals (such as rubber oil seals and felt seals) and non-contact seals (such as labyrinth seals). Contact seals (such as O-rings or lip seals) rely on the interference contact between the elastomer and the shaft surface to achieve sealing. Although the initial sealing effect is good, continuous friction during high-speed motor rotation leads to rapid wear of the seal, which not only shortens its service life but also generates heat and frictional resistance, reducing motor efficiency. This contradicts the design intent of high efficiency and low energy consumption of coreless motors. Non-contact seals (such as simple labyrinth grooves) avoid frictional loss, but their sealing capacity is limited, especially when facing highly penetrating liquids or fine dust, often proving inadequate. Their splash-proof or dustproof ratings are insufficient for more demanding applications. Therefore, a rotary seal structure for coreless motors is proposed to address the above problems. Utility Model Content
[0005] The purpose of this invention is to at least solve one of the aforementioned technical defects.
[0006] Therefore, one objective of this utility model is to propose a rotary sealing structure for a hollow cup motor to solve the problems mentioned in the background art and overcome the shortcomings of the prior art.
[0007] To achieve the above objectives, one embodiment of the present invention provides a rotary sealing structure for a hollow cup motor, comprising a body, a sealing ring, a bearing, and a main shaft, wherein a sealing ring is embedded inside the end face port of the body, and a bearing is embedded inside the sealing ring. A main shaft is inserted into the bearing, and the main shaft is connected to a rotor inside the machine body. The rotor inside the machine body is hollow and cup-shaped. The exposed part of the spindle has a spiral groove on its outer surface, and a wear-resistant bushing is fixedly connected to the inner ring end face of the bearing. The wear-resistant bushing is made of a self-lubricating material, and the inner hole of the wear-resistant bushing is a smooth cylindrical surface; The end of the wear-resistant bushing is closed and pressed onto the spindle; The outer surface of the spindle is provided with several dust-throwing ring grooves, and the openings of the dust-throwing ring grooves face the outside of the machine body.
[0008] Preferably, the sealing ring is made of rubber, and specifically, it is an O-ring.
[0009] The above technical solution is adopted: the sealing ring embedded inside the end face port of the machine body is made of rubber, specifically an O-ring, which plays a preliminary sealing role and prevents external dust and liquid from directly entering the motor from the gap between the end face port of the machine body and the main shaft.
[0010] The spiral grooves on the exposed surface of the spindle face outwards towards the spindle's outer end. When the spindle rotates at high speed, these grooves act like a miniature pump, creating a cyclone effect. Dust particles and liquids attempting to enter the motor are "pumped" outwards by this cyclone effect, effectively preventing contaminants from entering the motor. A wear-resistant bushing (made of PTFE, a self-lubricating material) is fixedly connected to the inner ring of the bearing. Its inner bore is a smooth cylindrical surface, maintaining a fixed radial clearance (5-10 μm) with the outer surface of the spindle. Due to the self-lubricating properties of the wear-resistant bushing, even slight momentary contact between the spindle and the bushing during high-speed rotation will not cause wear or jamming, ensuring normal spindle operation and sealing performance.
[0011] Several dust-throwing ring grooves are formed on the outer surface of the main shaft. These grooves have a V-shaped cross-section with an acute angle, and their openings face outwards towards the machine body. The dust-throwing ring grooves are located on the outer side of the spiral groove seal structure (closer to the external environment). When the main shaft rotates at high speed, the newly added dust-throwing ring grooves act like "armor" or a "first line of defense," similar in principle to the impeller of a centrifugal pump. Any liquid or larger particles that come into contact with the dust-throwing ring grooves will be violently thrown outwards radially under centrifugal force, moving away from the shaft sleeve clearance, thus significantly reducing the burden on the main spiral groove seal.
[0012] Preferably, the spindle is made of alloy steel and the maximum depth of the spiral groove is 0.2-0.3 mm.
[0013] Preferably, in any of the above embodiments, the spiral direction of the spiral groove is towards the outer end of the main shaft, and the wear-resistant bushing is laser-welded and sealed to the inner ring end face of the bearing.
[0014] This rotary seal structure employs a two-stage sealing mechanism. The dust-throwing ring groove uses centrifugal force to throw out larger particles and liquids, providing the first layer of protection; the spiral groove handles fine contaminants that have approached the shaft sleeve clearance, providing the second layer of protection. This dual-protection mechanism significantly improves the motor's sealing performance, effectively preventing dust and liquid from entering the motor and extending its service life. It is particularly effective against liquids and slurry contaminants: for liquids attempting to crawl along the shaft surface, the centrifugal force of the dust-throwing ring groove and the cyclone effect of the spiral groove are especially significant. Under the combined action of centrifugal force and cyclone force, liquid has difficulty entering the motor, thus ensuring normal operation of the motor in humid environments or conditions where it may come into contact with liquids. This rotary seal structure only requires an additional machining process on the existing motor shaft structure to process the dust-throwing ring groove, resulting in minimal changes to the overall motor structure. Therefore, the cost increase is negligible, yet it significantly improves the motor's sealing performance, offering high cost-effectiveness.
[0015] Preferably, the wear-resistant bushing is made of PTFE, and the wear-resistant bushing maintains a fixed radial clearance (5-10μm) with the outer surface of the spindle.
[0016] Preferably, in any of the above schemes, the cross-sectional shape of the dust-throwing ring groove 7 is V-shaped, and the angle of the dust-throwing ring groove is acute.
[0017] Compared with the prior art, the advantages and beneficial effects of this utility model are as follows: The rotary seal structure of this hollow cup motor employs a two-stage sealing mechanism. The dust-throwing ring groove uses centrifugal force to throw out larger particles and liquids, providing the first layer of protection. The spiral groove handles fine contaminants that have approached the shaft sleeve clearance, providing the second layer of protection. This dual-protection mechanism significantly improves the motor's sealing performance, effectively preventing dust and liquid from entering the motor and extending its service life. It is particularly effective against liquids and slurry contaminants: for liquids attempting to crawl along the shaft surface, the centrifugal force of the dust-throwing ring groove and the cyclone effect of the spiral groove are especially significant. Under the combined action of centrifugal force and cyclone force, liquid has difficulty entering the motor, thus ensuring normal operation of the motor in humid environments or conditions where it may come into contact with liquids. This rotary seal structure only requires an additional machining process on the existing motor shaft structure to process the dust-throwing ring groove, resulting in minimal changes to the overall motor structure. Therefore, the cost increase is negligible, yet it significantly improves the motor's sealing performance, offering high cost-effectiveness.
[0018] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description
[0019] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram of the structure of the body of this utility model; Figure 2 This is a schematic diagram of the main shaft of this utility model; Figure 3 This is a schematic diagram of the structure of this utility model after adding a wear-resistant bushing; Figure 4 This is a cross-sectional view of the present invention after the addition of a wear-resistant bushing.
[0020] In the diagram: 1-body, 2-sealing ring, 3-bearing, 4-spindle, 5-spiral groove, 6-wear-resistant bushing, 7-dust-throwing ring groove. Detailed Implementation
[0021] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this utility model, and should not be construed as limiting this utility model.
[0022] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.
[0023] like Figure 1-4 As shown, the rotary sealing structure of this hollow cup motor includes a body 1, a sealing ring 2, a bearing 3, and a main shaft 4. The sealing ring 2 is embedded inside the end face port of the body 1, and the bearing 3 is embedded inside the sealing ring 2. A main shaft 4 is inserted into the bearing 3. The main shaft 4 is connected to the rotor inside the machine body 1. The rotor inside the machine body 1 is hollow and cup-shaped. A spiral groove 5 is provided on the outer surface of the exposed part of the spindle 4, and a wear-resistant bushing 6 is fixedly connected to the inner ring end face of the bearing 3. The wear-resistant bushing 6 is made of self-lubricating material, and the inner hole of the wear-resistant bushing 6 is a smooth cylindrical surface; The end of the wear-resistant bushing 6 is closed and pressed onto the spindle 4; The outer surface of the main shaft 4 is provided with several dust-throwing ring grooves 7, and the openings of the dust-throwing ring grooves 7 face the outside of the machine body 1.
[0024] Example 1: The sealing ring 2 is made of rubber, specifically an O-ring. The spindle 4 is made of alloy steel, and the maximum depth of the spiral groove 5 is 0.2-0.3 mm. The spiral direction of the spiral groove 5 is towards the outer end of the spindle 4. The wear-resistant bushing 6 is laser-welded to the inner ring end face of the bearing 3 and sealed. The wear-resistant bushing 6 is made of PTFE, and maintains a fixed radial clearance (5-10 μm) between the wear-resistant bushing 6 and the outer surface of the spindle 4. The dust-throwing ring groove 7 has a V-shaped cross-section and an acute angle.
[0025] Example 2: The sealing ring 2 embedded inside the end face port of the machine body 1 is made of rubber, specifically an O-ring, which plays a preliminary sealing role to prevent external dust and liquid from directly entering the motor from the gap between the end face port of the machine body 1 and the main shaft 4.
[0026] The spiral groove 5, formed on the exposed outer surface of the main shaft 4, faces outwards towards the outer end of the main shaft 4. When the main shaft 4 rotates at high speed, the spiral groove 5 acts like a miniature pump, generating a cyclone effect. Dust particles and liquids attempting to enter the motor are "pumped" outwards and blown back into the external environment under the action of the cyclone effect, effectively preventing contaminants from entering the motor. The wear-resistant bushing 6 (made of PTFE and self-lubricating material) is fixedly connected to the inner ring end face of the bearing 3. Its inner hole is a smooth cylindrical surface and maintains a fixed radial clearance (5-10μm) with the outer surface of the main shaft 4. Due to the self-lubricating properties of the wear-resistant bushing 6, even if the main shaft 4 has a very slight momentary contact with the wear-resistant bushing 6 during high-speed rotation, it will not cause wear or jamming, ensuring the normal operation and sealing effect of the main shaft 4.
[0027] Several dust-throwing ring grooves 7 are formed on the outer surface of the main shaft 4. These grooves have a V-shaped cross-section with an acute angle, and their openings face outwards from the machine body 1. The dust-throwing ring grooves 7 are located on the outer side of the spiral groove 5 sealing structure (closer to the external environment). When the main shaft 4 rotates at high speed, the newly added dust-throwing ring grooves 7 act like "armor" or a "first line of defense," similar in principle to the impeller of a centrifugal pump. Any liquid or larger particles that come into contact with the dust-throwing ring grooves 7 will be violently thrown outwards radially under centrifugal force, moving away from the shaft sleeve clearance, thus significantly reducing the burden on the main spiral groove 5 seal.
[0028] The working principle of this utility model is as follows: The coreless motor has a power of 50W, a rated voltage of 24V, and a rated speed of 10000r / min. The motor body 1 is made of aluminum alloy to ensure good heat dissipation and structural strength.
[0029] Select a rubber O-ring 2 and embed it into the sealing groove inside the end face port of the body 1. Ensure that the O-ring 2 is securely installed without twisting or deformation to guarantee a good sealing effect.
[0030] Select a bearing 3 of appropriate specifications and install it in the corresponding position inside the machine body 1. Then, fix the wear-resistant bushing 6 made of PTFE material to the inner ring end face of the bearing 3 by laser welding, ensuring good welding seal and no leakage. The inner hole of the wear-resistant bushing 6 is a smooth cylindrical surface, maintaining a fixed radial clearance of 5-10μm with the outer surface of the spindle 4.
[0031] The spindle 4 is made of alloy steel to ensure sufficient strength and rigidity. A helical groove 5 is precision-machined onto the exposed outer surface of the spindle 4. The maximum depth of the helical groove 5 is 0.2-0.3 mm, with the helix pointing towards the outer end of the spindle 4. On the outer side of the sealing structure of the helical groove 5 (the side closer to the external environment), several dust-throwing ring grooves 7 with a V-shaped cross-section and an acute angle are also precision-machined. The machined spindle 4 is inserted into the bearing 3 and connected to the rotor inside the machine body 1. The rotor is a hollow cup shape and rotates synchronously with the spindle 4 via a key connection or other means.
[0032] The hollow cup motor with the rotary seal structure installed underwent performance testing. During the test, the motor's operation was simulated under various conditions, including high-speed rotation, humid environments, and the presence of dust and liquid splashes. The effectiveness and reliability of the rotary seal structure were verified by measuring the dust and liquid content inside the motor, the operational stability of the main shaft 4, and the motor's performance parameters. Test results show that the rotary seal structure effectively prevents dust and liquid from entering the motor, the main shaft 4 operates stably, the motor's performance parameters meet design requirements, and it exhibits good sealing performance and service life.
[0033] Compared with the prior art, the present invention has the following advantages: The rotary seal structure of this hollow cup motor employs a two-stage sealing mechanism. The dust-throwing ring groove 7 uses centrifugal force to throw out larger particles and liquids, providing the first layer of protection. The spiral groove 5 handles fine contaminants that have approached the shaft sleeve gap, providing the second layer of protection. This dual-protection mechanism significantly improves the motor's sealing performance, effectively preventing dust and liquid from entering the motor and extending its service life. It is particularly effective against liquids and slurry contaminants: the centrifugal force of the dust-throwing ring groove 7 and the cyclone effect of the spiral groove 5 are especially effective against liquids attempting to crawl along the shaft surface. Under the combined action of centrifugal force and cyclone force, liquid has difficulty entering the motor, thus ensuring normal operation of the motor in humid environments or conditions where it may come into contact with liquids. This rotary seal structure only requires an additional machining process on the existing motor shaft structure to process the dust-throwing ring groove 7, resulting in minimal changes to the overall motor structure. Therefore, the cost increase is negligible, yet it significantly improves the motor's sealing performance, offering high cost-effectiveness.
Claims
1. A rotary sealing structure for a hollow cup motor, characterized in that, Includes a body (1), a sealing ring (2), a bearing (3), and a main shaft (4). The sealing ring (2) is embedded inside the end face port of the body (1), and the bearing (3) is embedded inside the sealing ring (2). A main shaft (4) is inserted into the bearing (3), and the main shaft (4) is connected to the rotor inside the machine body (1). The rotor inside the machine body (1) is a hollow cup shape. The exposed part of the main shaft (4) has a spiral groove (5) on its outer surface, and a wear-resistant bushing (6) is fixedly connected to the inner ring end face of the bearing (3). The wear-resistant bushing (6) is made of self-lubricating material, and the inner hole of the wear-resistant bushing (6) is a smooth cylindrical surface; The end of the wear-resistant bushing (6) is closed and pressed onto the main shaft (4); The outer surface of the main shaft (4) is provided with a plurality of dust-throwing ring grooves (7), the openings of the dust-throwing ring grooves (7) facing the outside of the machine body (1).
2. The rotary sealing structure of a hollow cup motor as described in claim 1, characterized in that: The sealing ring (2) is made of rubber, and the sealing ring (2) is specifically an O-ring.
3. The rotary sealing structure of a hollow cup motor as described in claim 2, characterized in that: The main shaft (4) is made of alloy steel, and the maximum depth of the spiral groove (5) is 0.2-0.3 mm.
4. The rotary sealing structure of a hollow cup motor as described in claim 3, characterized in that: The spiral direction of the spiral groove (5) is towards the outer end of the main shaft (4), and the wear-resistant bushing (6) is laser welded to the inner ring end face of the bearing (3) and sealed.
5. The rotary sealing structure of a hollow cup motor as described in claim 4, characterized in that: The wear-resistant bushing (6) is made of PTFE, and the wear-resistant bushing (6) maintains a fixed radial gap (5-10μm) with the outer surface of the spindle (4).
6. The rotary sealing structure of a hollow cup motor as described in claim 5, characterized in that: The cross-sectional shape of the dust-throwing ring groove (7) is V-shaped, and the angle of the dust-throwing ring groove (7) is acute.