Shield pump for realizing self-balancing of axial force of rotor
By employing a sliding thrust bearing and an internal circulation channel structure in the canned motor pump, the problem of thrust bearing wear due to axial force is solved, achieving self-balancing of axial force and improving the service life of the canned motor pump.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- LEO GRP PUMP TECH CO LTD
- Filing Date
- 2025-07-08
- Publication Date
- 2026-05-26
AI Technical Summary
When the axial force on the impeller shaft of an existing canned motor pump is large, the thrust bearing counteracts the axial force by squeezing against it, which leads to increased wear and reduces the service life of the canned motor pump.
A sliding thrust bearing is used, and a bearing flow channel is set in the sliding thrust bearing. When the conveying medium rotates at high speed, the axial force is reduced through the bearing flow channel, forming an internal circulation channel to balance the axial force.
By utilizing the flow of the medium within the sliding thrust bearing, bearing wear is reduced, thereby extending the service life of the canned pump.
Smart Images
Figure CN224282948U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the technical field of canned motor pumps, and in particular to a canned motor pump that achieves self-balancing of rotor axial force. Background Technology
[0002] Canned motor pumps are centrifugal, seal-less pumps. Both the pump and the drive motor are enclosed within a pressure vessel filled with the pumped medium, which has only a static seal. Canned motor pumps eliminate the rotary shaft seal found in traditional centrifugal pumps, allowing lubrication and heat dissipation through the pumped medium itself, thus eliminating the need for additional lubricating grease and cooling fans.
[0003] Currently, Chinese patent application number 2024213300889 discloses a canned pump internal circulation flow regulation structure and a canned pump, including an impeller shaft that passes through a shielding sleeve, with an axial through hole in its center and a radial throttling hole on its side wall communicating with the axial through hole; the front end cover plate of the shielding sleeve has a cover plate through hole, and a bottom bearing is installed at its bottom, which is sleeved on the end of the impeller shaft away from the inlet of the canned pump, and an opening is provided on the bottom bearing, and the impeller shaft is mounted on the front end cover plate through a thrust bearing.
[0004] Regarding the aforementioned technologies, although the conveying medium can cool the thrust bearing, when the axial force on the impeller shaft is large, the thrust bearing on the impeller shaft can only offset the axial force by squeezing against it, which leads to increased wear of the thrust bearing and reduces the service life of the canned pump. Therefore, there are certain areas for improvement. Utility Model Content
[0005] To improve the service life of canned motor pumps, this application provides a canned motor pump that achieves self-balancing of rotor axial force.
[0006] The canned motor pump that achieves self-balancing of rotor axial force provided in this application adopts the following technical solution:
[0007] A canned motor pump that achieves self-balancing of rotor axial force includes a motor housing, and a front motor cover and a rear motor cover respectively disposed at both ends of the motor housing. A shielding sleeve is disposed inside the motor housing, a stator is disposed between the shielding sleeve and the motor housing, a main shaft is disposed inside the shielding sleeve, a rotor is disposed on the main shaft, and both the front motor cover and the rear motor cover are provided with sliding thrust bearings assembled with the main shaft.
[0008] The sliding thrust bearing is provided with a bearing flow channel, the main rotating shaft is provided with a central hole flow channel along the axial direction, and the main rotating shaft is provided with a flow channel outlet. The bearing flow channel, the inner cavity of the shielding sleeve, the bearing flow channel, the central hole flow channel and the flow channel outlet form an internal circulation flow channel.
[0009] Preferably, the sliding thrust bearing includes an outer bearing ring and an inner bearing sleeve. The outer bearing ring is mounted on the front end cover and the rear end cover of the motor. The inner bearing sleeve is disposed on the main rotating shaft and mounted in the outer bearing ring. The bearing flow channel is formed between the outer bearing ring and the inner bearing sleeve.
[0010] Preferably, the bearing inner ring includes a bearing inner ring and a thrust boss integrally formed on the bearing inner ring. The bearing outer ring is slidably sleeved on the outside of the bearing inner ring. The thrust boss abuts against the end face of the bearing outer ring. The bearing flow channel is formed between the bearing inner ring, the thrust boss and the bearing outer ring.
[0011] Preferably, the main shaft and the bearing inner sleeve are installed by a flat key or spline.
[0012] Preferably, a plurality of bearing through grooves are formed on the end face of the outer ring of the bearing, and the bearing through grooves are respectively connected to the inner wall and the outer wall of the outer ring of the bearing.
[0013] Preferably, a bearing guide groove is formed on the inner wall of the outer ring of the bearing.
[0014] Preferably, a bearing groove is provided on the inner wall edge of the outer ring of the bearing.
[0015] Preferably, one end of the bearing channel in the sliding thrust bearing of the front cover of the motor is connected to the outside, and the other end is connected to the inside of the shielding sleeve.
[0016] Preferably, at least one impeller is mounted on the main shaft, and the flow channel outlet is located at the inlet position of the impeller.
[0017] In summary, this application includes at least one of the following beneficial technical effects:
[0018] In this application, a sliding thrust bearing is used instead of a traditional thrust bearing. A bearing flow channel is formed in the sliding thrust bearing. The conveying medium enters through the bearing flow channel in the sliding thrust bearing. When the sliding thrust bearing rotates at high speed, the conveying medium can play a role in reducing a certain axial force in the sliding thrust bearing, thereby improving the service life of the canned pump. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of a canned motor pump.
[0020] Figure 2 This is a schematic diagram of the internal structure of a canned motor pump.
[0021] Figure 3 This is a cross-sectional schematic diagram of a canned motor pump.
[0022] Figure 4This is a schematic diagram of the first structure of a sliding thrust bearing.
[0023] Figure 5 This is a schematic diagram of the second structure of a sliding thrust bearing.
[0024] Figure 6 This is a schematic diagram of the installation of the bearing inner ring and bearing outer ring.
[0025] Explanation of reference numerals in the attached drawings: 1. Motor housing; 2. Main shaft; 3. Front cover of motor; 4. Rear cover of motor; 5. Shielding sleeve; 6. Stator; 7. Rotor; 8. Sliding thrust bearing; 81. Bearing outer ring; 82. Bearing inner sleeve; 821. Bearing inner ring; 822. Thrust boss; 83. Bearing guide groove; 84. Bearing through groove; 85. Bearing counterslot; 9. Impeller; 10. Bearing flow channel; 11. Center hole flow channel; 12. Flow channel outlet. Detailed Implementation
[0026] The following is in conjunction with the appendix Figure 1-4 This application will be described in further detail.
[0027] A canned pump that achieves self-balancing of rotor axial force, refer to Figure 1 and Figure 2 As shown, it includes a motor housing 1, a main shaft 2, a front motor cover 3, a rear motor cover 4, and a shielding sleeve 5. The motor housing 1 extends through both ends along the axial direction. A motor chamber is provided inside the motor housing 1. The front motor cover 3 and the rear motor cover 4 are installed at both ends of the motor housing 1 through flanges.
[0028] The shielding sleeve 5 is installed inside the motor housing 1. The two ends of the shielding sleeve 5 are respectively installed on the front end cover 3 and the rear end cover 4 of the motor. The shielding sleeve 5 is fixed to the front end cover 3 and the rear end cover 4 of the motor by welding, thereby achieving a seal between the shielding sleeve 5 and the front end cover 3 and the rear end cover 4 of the motor.
[0029] A stator 6 is installed inside the motor housing 1. The stator 6 is located between the shielding sleeve 5 and the motor housing 1. The main shaft 2 is installed inside the shielding sleeve 5. A rotor 7 is installed on the main shaft 2. A gap is maintained between the rotor 7 and the shielding sleeve 5.
[0030] The front cover 3 of the motor has a bearing mounting port in the middle, and the rear cover 4 of the motor has a bearing mounting position in the middle. The front cover 3 of the motor has a bearing mounting port, and the rear cover 4 of the motor has a bearing mounting position. The main shaft 2 is mounted on the sliding thrust bearing 8, thereby realizing the high-speed rotation of the main shaft 2 in the motor housing 1. The bearing mounting port passes through the front cover 3 of the motor, and the main shaft 2 passes through the middle of the front cover 3 of the motor and extends to the outside.
[0031] At least one impeller 9 is mounted on one end of the main shaft 2 outside the front cover 3 of the motor. In this embodiment, there are two impellers 9, which are installed on the main shaft 2 at an interval. In one embodiment, the impellers 9 are mounted on the main shaft 2 by a flat key. In another embodiment, the impellers are mounted on the main shaft 2 by a spline. The method of mounting the impellers 9 on the main shaft 2 can be set according to the actual situation.
[0032] The sliding thrust bearing 8 is provided with a bearing flow channel 10. The sliding thrust bearing 8 located at the front end cover 3 of the motor is connected to the outside through the bearing flow channel 10. The connection point is close to the side of the rear cover plate of the impeller 9. The other end of the bearing flow channel 10 is connected to the inside of the shielding sleeve 5.
[0033] The sliding thrust bearing 8 located at the rear end cover 4 of the motor is connected to the interior of the shielding sleeve 5 by the setting of the bearing flow channel 10, and the other end of the bearing flow channel 10 is connected to the bearing mounting position.
[0034] A central flow channel 11 is provided axially inside the main shaft 2. In one embodiment, one end of the central flow channel 11 is connected to the end of the main shaft 2 near the rear end cover 4 of the motor, and the other end of the central flow channel 11 is closed. A flow channel outlet 12 is provided on the side wall of the main shaft 2, located at the inlet position of the impeller 9. In another embodiment, one end of the central flow channel 11 is connected to the end of the main shaft 2 near the rear end cover 4 of the motor, and the flow channel outlet 12 is located at the other end of the main shaft 2 and connected to the central flow channel 11.
[0035] The bearing flow channel 10, the inner cavity of the shielding sleeve 5, the bearing flow channel 10, the central hole flow channel 11, and the flow channel outlet 12 form an internal circulation flow channel. When the impeller 9 rotates at high speed, the impeller 9 inlet generates negative pressure to draw in the conveying medium. The conveying medium is thrown out from the outer circumference of the impeller 9, enters the inner cavity of the shielding sleeve 5 through the bearing flow channel 10, passes through the gap between the rotor 7 and the shielding sleeve 5, enters the central hole flow channel 11 through the bearing flow channel 10 of the motor rear end cover 4, and is discharged from the flow channel outlet 12 through the central hole flow channel 11, thereby completing the flow of the conveying medium in the internal circulation flow channel.
[0036] The structure of the sliding thrust bearing 8 is described below.
[0037] Reference Figure 3 , Figure 4 and Figure 5As shown, the sliding thrust bearing 8 includes an outer bearing ring 81 and an inner bearing sleeve 82. The outer bearing ring 81 is mounted on the front end cover 3 and the rear end cover 4 of the motor. The outer bearing ring 81 is interference-fitted with the bearing mounting port of the front end cover 3 and the bearing mounting position of the rear end cover 4. The inner bearing sleeve 82 is disposed on the main shaft 2 and mounted in the outer bearing ring 81. The bearing flow channel 10 is formed between the outer bearing ring 81 and the inner bearing sleeve 82.
[0038] The bearing inner sleeve 82 includes an inner bearing ring 821 and a thrust boss 822 integrally formed on the inner bearing ring 821. The outer bearing ring 81 is slidably sleeved on the outer side of the inner bearing ring 821. The thrust boss 822 abuts against the end face of the outer bearing ring 81. A bearing flow channel 10 is formed between the inner bearing ring 821, the thrust boss 822, and the outer bearing ring 81. In one embodiment, the main shaft 2 and the bearing inner sleeve 82 are installed via a flat key. In another embodiment, the main shaft 2 and the bearing inner sleeve 82 are installed via a spline. The installation method between the main shaft 2 and the bearing inner sleeve 82 can be selected according to the actual situation, and this embodiment does not impose a specific limitation.
[0039] A bearing guide groove 83 is formed on the inner wall of the outer ring 81 of the bearing. The bearing guide groove 83 is located on the inner wall where the outer ring 81 contacts the inner ring 821. The bearing guide groove 83 extends from one end of the outer ring 81 to the other end. When the conveying medium enters the bearing flow channel 10 from the outside, the bearing guide groove 83 ensures that even when the radial force of the main shaft 2 is too large, the outer ring 81 and the inner ring 821 of the bearing are in a tight contact in the radial direction, allowing some of the conveying medium to pass through. Furthermore, the conveying medium can form a liquid film between the outer ring 81 and the inner ring 821 of the bearing, preventing dry friction between the inner ring 821 and the outer ring 81 of the bearing.
[0040] Multiple bearing through grooves 84 are formed on the end face of the outer ring 81 of the bearing. These grooves are spaced apart circumferentially on the end face of the outer ring 81. The bearing through grooves 84 are located at the end of the outer ring 81 near the thrust boss 822, and they connect to the inner and outer walls of the outer ring 81. When the axial force of the main shaft 2 is too large, the outer ring 81 of the bearing abuts against the thrust boss 822. The bearing through grooves 84 allow the conveying medium to form a liquid film on the outer ring 81, thereby reducing wear and improving the service life of the sliding thrust bearing 8.
[0041] Bearing grooves 85 are provided on the inner wall edge of the outer ring 81 of the bearing. In one embodiment, bearing grooves 85 are provided on the inner wall edges of both ends of the outer ring 81 of the bearing.
[0042] By setting the bearing groove 85, it is known that the axial force increases during the rotation of the main shaft 2. The presence of the bearing groove 85 increases the volume of the intermediate transition cavity when the inner ring 821 and the outer ring 81 of the bearing are engaged, that is, the volume of the bearing flow channel 10, which increases the pressure difference of each force-bearing surface of the inner ring 821 of the bearing, thereby generating a reverse axial force to balance the axial force generated by the main shaft 2.
[0043] Reference Figure 6 As shown, its working mechanism is as follows: when the inlet of the bearing flow channel 10 is under pressure P1, under the action of pressure difference, after the conveying medium passes through the bearing inner ring 821 and the bearing outer ring 81, the pressure drops to P2. Due to the presence of the bearing groove 85, the axial force surface is increased. The thrust boss 822 generates part of the reverse axial force under the pressure of P2, which makes the main shaft 2 tend to move to the right.
[0044] During the rotation of the canned motor pump, due to the difference in pressure and area between the front and rear cover plates, the impeller 9 generates an axial force to the left, causing the thrust boss 822 to move to the left and approach the outer ring 81 of the bearing. The axial contact gap between the two is reduced. Under the action of pressure difference, the conveyed medium will pass through the bearing flow channel 10 between the outer ring 81 and the inner ring 821 of the bearing, thereby generating a reverse axial force to the right on the thrust boss 822. Finally, after the medium passes through the bearing flow channel 10, the pressure gradually decreases to P3.
[0045] This application achieves integrated axial and radial support by using a sliding thrust bearing 8, which reduces assembly process requirements and increases reliability compared to a separate radial and axial design.
[0046] The axial force balancing structure of the inner ring 821 and the outer ring 81 of the bearing optimizes the spatial layout at the corner to form an intermediate transition cavity, increases the pressure difference before and after the bearing flow channel 10, and achieves the effect of adaptive adjustment of axial force. Furthermore, by adjusting the balance between axial force and reverse axial force, the gap between the inner ring 821 and the outer ring 81 of the bearing is changed to meet the width required for liquid film formation, reducing the risk of dry friction of the sliding thrust bearing 8 and increasing its service life.
[0047] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.
Claims
1. A canned motor pump that achieves self-balancing of rotor axial force, comprising a motor housing (1), and a front motor cover (3) and a rear motor cover (4) respectively disposed at both ends of the motor housing (1), wherein a shielding sleeve (5) is disposed inside the motor housing (1), a stator (6) is disposed between the shielding sleeve (5) and the motor housing (1), a main shaft (2) is disposed inside the shielding sleeve (5), and a rotor (7) is disposed on the main shaft (2), characterized in that, Both the front end cover (3) and the rear end cover (4) of the motor are provided with sliding thrust bearings (8) that are assembled with the main shaft (2); The sliding thrust bearing (8) is provided with a bearing flow channel (10), the main rotating shaft (2) is provided with a central hole flow channel (11) along the axial direction, and the main rotating shaft (2) is provided with a flow channel outlet (12). The bearing flow channel (10), the inner cavity of the shielding sleeve (5), the central hole flow channel (11) and the flow channel outlet (12) form an internal circulation flow channel.
2. A canned pump for achieving self-balancing of rotor axial force according to claim 1, characterized in that, The sliding thrust bearing (8) includes an outer bearing ring (81) and an inner bearing sleeve (82). The outer bearing ring (81) is mounted on the front end cover (3) of the motor and the rear end cover (4) of the motor. The inner bearing sleeve (82) is disposed on the main shaft (2) and mounted in the outer bearing ring (81). The bearing flow channel (10) is formed between the outer bearing ring (81) and the inner bearing sleeve (82).
3. A canned pump for achieving self-balancing of rotor axial force according to claim 2, characterized in that, The bearing inner sleeve (82) includes a bearing inner ring (821) and a thrust boss (822) integrally formed on the bearing inner ring (821). The bearing outer ring (81) is slidably sleeved on the outside of the bearing inner ring (821). The thrust boss (822) abuts against the end face of the bearing outer ring (81). The bearing inner ring (821), the thrust boss (822) and the bearing outer ring (81) form the bearing flow channel (10).
4. A canned pump for achieving self-balancing of rotor axial force according to claim 2, characterized in that, The main shaft (2) and the bearing inner sleeve (82) are connected by a flat key or spline.
5. A canned pump for achieving self-balancing of rotor axial force according to claim 2, characterized in that, The bearing outer ring (81) has multiple bearing through grooves (84) on its end face, and the bearing through grooves (84) are respectively connected to the inner wall and the outer wall of the bearing outer ring (81).
6. A canned pump for achieving self-balancing of rotor axial force according to claim 2, characterized in that, The bearing guide groove (83) is provided on the inner wall of the outer ring (81) of the bearing.
7. A canned pump for achieving self-balancing of rotor axial force according to claim 2, characterized in that, The bearing outer ring (81) has a bearing groove (85) on the inner wall edge.
8. A canned pump for achieving self-balancing of rotor axial force according to claim 1, characterized in that, The bearing channel (10) located in the sliding thrust bearing (8) of the front cover (3) of the motor is connected to the outside at one end and to the inside of the shielding sleeve (5) at the other end.
9. A canned pump for achieving self-balancing of rotor axial force according to claim 1, characterized in that, At least one impeller (9) is installed on the main shaft (2), and the flow channel outlet (12) is located at the inlet position of the impeller (9).