阅读说明：本技术 小型堆屏蔽泵推力轴承结构 (Thrust bearing structure of small-sized reactor shield pump ) 是由 刁国鑫 王伟光 于勇 吕向平 索文旭 马德宇 姜丽娟 张智 刘慧昌 柴文虎 张海 于 2021-09-14 设计创作，主要内容包括：本发明涉及一种小型堆屏蔽泵推力轴承结构,上推力轴承座(15)、下推力轴承座(16)通过各自伸出的外沿由螺栓紧固在机座(1)上,上推力轴承座(15)中装有压缩弹簧(3),压缩弹簧(3)下部安装有弹簧板(4),弹簧板(4)为整环结构,弹簧板(4)外的上平衡块(5)与上推力轴承座(15)通过平衡块限位销(7)限位,相邻的上平衡块(5)与下平衡块(6)通过下平衡块(6)上的柱面配合,上平衡块(5)与下平衡块(6)沿弹簧板(4)周向均布本发明轴承设计为上大下小,较小的下推力瓦满足承载要求前提下,降低了阻力矩,轴承设计为上弹簧下刚性结构,在起动到稳态运行过程中下推力瓦与推力盘分离从而减小了摩擦损耗。(The invention relates to a thrust bearing structure of a small-sized stack shield pump, an upper thrust bearing seat (15) and a lower thrust bearing seat (16) are fastened on a machine base (1) by bolts through respectively extending outer edges, a compression spring (3) is arranged in the upper thrust bearing seat (15), a spring plate (4) is arranged at the lower part of the compression spring (3), the spring plate (4) is of an integral ring structure, an upper balance block (5) and an upper thrust bearing seat (15) outside the spring plate (4) are limited by a balance block limiting pin (7), the adjacent upper balance block (5) and a lower balance block (6) are matched through a cylindrical surface on the lower balance block (6), the upper balance block (5) and the lower balance block (6) are uniformly distributed along the circumferential direction of the spring plate (4), the thrust bearing structure is designed to be large at the top and small at the bottom, the resistance moment is reduced on the premise that a smaller lower thrust shoe meets the bearing requirement, the bearing is designed to be of an upper spring lower rigid structure, the thrust pads are separated from the thrust disk during startup to steady state operation to reduce frictional losses.)

1. The utility model provides a small-size heap canned motor pump thrust bearing structure which characterized by: an upper thrust bearing seat (15) and a lower thrust bearing seat (16) are fastened on a machine base (1) through bolts through outer edges extending out of the upper thrust bearing seat (15) and the lower thrust bearing seat respectively, a compression spring (3) is arranged in the upper thrust bearing seat (15), a spring plate (4) is arranged at the lower part of the compression spring (3), the spring plate (4) is of an integral ring structure, an upper balance block (5) outside the spring plate (4) and the upper thrust bearing seat (15) are limited through a balance block limiting pin (7), an adjacent upper balance block (5) and a lower balance block (6) are matched through a cylindrical surface on the lower balance block (6), the upper balance block (5) and the lower balance block (6) are uniformly distributed along the circumferential direction of the spring plate (4), an upper thrust shoe base (9) is in contact with the lower balance block (6), the upper thrust shoe base (9) is radially fixed by a limiting pin (17) on the upper thrust bearing seat (15), the upper thrust shoe base (9) is axially fixed by a limiting screw (18) on the upper thrust bearing seat (15), the upper thrust pad (10) is embedded in the upper thrust pad base (9), the lower thrust pad base (11) is installed in the lower thrust bearing seat (16), the lower thrust pad (12) is embedded in the lower thrust pad base (11), and the outer ring gland (14) and the inner ring gland (13) are installed on the outer diameter side and the inner diameter side of the lower thrust pad base (11).

2. The small stack canned motor pump thrust bearing structure of claim 1, wherein: the upper thrust pad (10) is large in pad surface, the lower thrust pad (12) is small in pad surface, the thrust disc (2) is in a circular truncated cone shape and is positioned between the upper thrust pad (10) and the lower thrust pad (12), and the thrust disc (2) and the rotating shaft (8) are fixedly installed together.

Technical Field

The invention relates to a thrust bearing structure of a small-sized stack shield pump.

Background

The small reactor is characterized by integrated design, namely a shielding pump, a reactor and an evaporator form a module, the technical principle of the small reactor is similar to that of a third-generation large reactor, the small reactor pushes a primary coolant to circulate between the reactor and the evaporator through the shielding pump, heat energy exchange between the reactor core and the evaporator is realized, high-pressure steam is generated, and power generation is realized through a generator set. The small reactor has the advantages of small occupied area, can realize the multiple purposes of nuclear energy, such as different requirements of urban heat supply, industrial steam supply and the like, and is suitable for multi-scene application of industrial parks, islands, high-energy-consumption enterprises and self-contained energy sources and the like.

The rotor and thrust bearing of the reactor shield pump are both immersed in the cooling medium carried by the pump. The rotor of the large-scale stack shield pump is heavy in wet weight and is equivalent to the reverse thrust generated by a pump impeller, so that the thrust bearing can adopt an up-and-down symmetrical structure. The rotor of the small-sized reactor shield pump is light, the main pump rises along with the rotating speed after being started, the reverse thrust generated by the shield pump is far larger than the wet weight of the rotor, the thrust bearing is influenced by the wet weight of the rotor in a short time after the thrust bearing starts to run at a low speed, the thrust bearing is stressed downwards, and the stress of the steady-state running time is upwards. There are patents: water-lubricated bidirectional working thrust bearing device, publication No.: CN 205078606U, be applicable to large-scale reactor coolant canned motor pump, the structure is symmetry from top to bottom, adopts two-way pretension spring structure for anti-impact, and upper and lower thrust tile follows the thrust dish all the time, and resistance moment is great when starting like this, and is high to canned motor pump starting performance requirement, and the friction loss is also big during the operation, if use in canned motor pump of the small-size heap of power own, because the friction loss that produces in bearing department, can make canned motor pump efficiency very low.

The invention content is as follows:

the invention aims to design a thrust bearing structure of a shield pump of a small reactor, which can effectively reduce the resistance moment borne by the shield pump during starting and the running loss at the thrust bearing after steady-state running.

The technical scheme of the invention is as follows: a thrust bearing structure of a small-sized stack shielding pump is characterized in that an upper thrust bearing seat (15) and a lower thrust bearing seat (16) are fastened on a machine base (1) through bolts through respectively extending outer edges, a compression spring (3) is installed in the upper thrust bearing seat (15), a spring plate (4) is installed on the lower portion of the compression spring (3), the spring plate (4) is of a whole-ring structure, an upper balance block (5) and the upper thrust bearing seat (15) outside the spring plate (4) are limited through a balance block limiting pin (7), an adjacent upper balance block (5) and a lower balance block (6) are matched through a cylindrical surface on the lower balance block (6), the upper balance block (5) and the lower balance block (6) are uniformly distributed along the circumferential direction of the spring plate (4), an upper thrust tile base (9) is in contact with the lower balance block (6), the upper thrust tile base (9) is radially fixed through a limiting pin (17) on the upper thrust bearing seat (15), the axial direction of an upper thrust tile base (9) is fixed by a limit screw (18) on an upper thrust bearing seat (15), an upper thrust tile (10) is embedded in the upper thrust tile base (9), a lower thrust tile base (11) is installed in a lower thrust bearing seat (16), a lower thrust tile (12) is embedded in the lower thrust tile base (11), and an outer ring gland (14) and an inner ring gland (13) are installed on the outer diameter side and the inner diameter side of the lower thrust tile base (11).

The upper thrust pad (10) is large in pad surface, the lower thrust pad (12) is small in pad surface, the thrust disc (2) is in a circular truncated cone shape and is positioned between the upper thrust pad (10) and the lower thrust pad (12), and the thrust disc (2) and the rotating shaft (8) are fixedly installed together.

The working principle of the invention is as follows:

the thrust bearing device is positioned at the upper part of the shield pump, and the upper thrust pad and the lower thrust pad are contacted with a thrust disc of a rotor of the shield pump and used for bearing the axial force applied to the rotor when the shield pump operates. The canned motor pump is installed in the pipeline of the main cooling loop of the whole reactor, and the impeller at the lower part of the pump rotor is positioned in the pipeline. The thrust bearing of the small-sized pile shield pump has small volume and small wet weight of a rotor, and is far smaller than the force generated by the impeller, so that the bearing bush adopts a form of large area and small area, and is simultaneously designed into a rigid structure with a pre-tightening spring at the upper part and a rigid structure at the lower part. Thus, in the initial starting stage of the canned motor pump, namely under the condition of low rotating speed, the axial force generated by the impeller is smaller than the wet weight of the rotor, the axial force of the canned motor pump is downward, the lower thrust bearing can bear the axial force, the upper thrust bearing is only subjected to the preload of the extension of the spring at the moment, although the friction force is not reduced along with the reduction of the contact area, the lower thrust shoe with the smaller shoe diameter can reduce the friction moment received during the starting period of the pump, namely the resistance moment, and the pump is accelerated towards the steady rated point along with the increase of the rotating speed, the impeller force is balanced with the wet weight of the rotor and then is larger than the wet weight of the rotor, at the moment, the thrust disc starts to push up the thrust bearing, namely the spring compression of the upper thrust bearing, and the lower thrust shoe is in a rigid structure and does not follow the thrust disc, so the thrust disc is separated from the lower thrust shoe, namely the friction loss caused by the contact with the lower thrust shoe is not generated any more. In conclusion, compared with the thrust bearing with the structure of the vertically symmetrical double-sided preload spring, the structure of the invention has the advantages of reducing the starting resistance moment and the friction loss.

The invention has the technical effects that:

according to the thrust bearing structure of the shield pump, the resultant force, namely the wet weight of the rotor, is small when the shield pump is started, and the reverse thrust caused by the impeller of the pump after operation is large, so that the thrust bearing structure is designed to be asymmetrical up and down: the upper thrust pad has a large area and the lower thrust pad has a small area. Therefore, on the premise of meeting the bearing specific pressure required by starting and running of the canned motor pump, the lower thrust pad with smaller pad diameter is adopted, and the resistance moment is reduced when the canned motor pump is started.

The thrust disc designs into the round platform shape, except that the form of big-end-up, reduced the stirring loss and still increased the space of bearing department and increased the water storage capacity of bearing chamber promptly, on handling potential accident like this, when losing equipment cooling water, more deposit water can reduce the programming rate of equipment, help the extension of operating time under the canned motor pump accident operating mode.

The shield pump thrust bearing structure combines the characteristic that the axial impact of the shield pump of the small reactor is relatively small, adopts the upper pre-tightening spring and the lower rigid structure, when the pump is in steady-state operation, the load borne by the thrust bearing is completely on the upper thrust bearing, the thrust disc is separated from the lower thrust bearing, namely the lower thrust pad does not bear the load after the pump is smoothly started, and thus the friction loss and the stirring loss between the thrust disc and the lower thrust pad are reduced.

Drawings

FIG. 1 is an overall view of a thrust bearing

FIG. 2 is a sectional view A-A of the thrust bearing

FIG. 3 upper thrust bearing partial cross-sectional view B-B

FIG. 4 is a partially enlarged view of the thrust bearing

Detailed Description

As shown in fig. 1, an upper thrust bearing seat 15 and a lower thrust bearing seat 16 are fastened on a base 1 by bolts through respective extending outer edges, as shown in fig. 3, a compression spring 3 is installed in the upper thrust bearing seat 15, a spring plate 4 is installed at the lower part of the compression spring 3, the spring plate 4 is of a whole ring structure, an upper balance block 5 and an upper thrust bearing seat 15 outside the spring plate 4 are limited by a balance block limiting pin 7, an adjacent upper balance block 5 and a lower balance block 6 are matched through a cylindrical surface on the lower balance block 6, the upper balance block 5 and the lower balance block 6 are uniformly distributed along the circumferential direction of the spring plate 4, an upper thrust shoe base 9 is contacted with the lower balance block 6, the upper thrust shoe base 9 is radially fixed by a limiting pin 17 on the upper thrust bearing seat 15, the upper thrust shoe base 9 is axially fixed by a limiting screw 18 on the upper thrust bearing seat 15 as shown in fig. 2, the upper thrust shoe 10 is embedded in the upper thrust shoe base 9, as shown in fig. 4, the lower thrust shoe base 11 is mounted in the lower thrust bearing housing 16, the lower thrust shoe 12 is embedded in the lower thrust shoe base 11, and the outer ring gland 14 and the inner ring gland 13 are mounted on the outer diameter side and the inner diameter side of the lower thrust shoe base 11.

The upper thrust pad 10 has a large pad surface, the lower thrust pad 12 has a small pad surface, the thrust disc 2 is in a circular truncated cone shape and is positioned between the upper thrust pad 10 and the lower thrust pad 12, and the thrust disc 2 and the rotating shaft 8 are fixedly installed together.

The thrust bearing structure of the small-sized pile shield pump is combined with the characteristics that the wet weight of a rotor of the small-sized pile shield pump is small and the downward load is small in the starting process, the thrust bearing is designed to be in a form of being large at the top and small at the bottom, the load ratio is about 1.8 times, namely, an upper tile is required to be about 1.8 times larger than a lower tile, the tile ratio is designed to be 1.3, the inner side of a base of the shield pump is designed to be in a double-spigot form, and therefore the upper bearing seat and the lower bearing seat can be sequentially installed on the base. The upper thrust bearing seat 15 and the lower thrust bearing seat 16 are fastened on the machine base 1 by bolts through the outer edges extending out respectively, FIG. 2 is a bottom view of an upper thrust bearing, as shown in FIG. 3, an upper thrust bearing seat 15 is provided with a compression spring 3, a spring plate 4 is installed at the lower part of the compression spring 3, the spring plate 4 is of an integral ring structure, an upper balance block 5 outside the spring plate 4 and the upper thrust bearing seat 15 are limited by a balance block limiting pin 7, adjacent upper balance blocks 5 and lower balance blocks 6 are matched by a cylindrical surface on the lower balance block 6, the upper balance blocks 5 and the lower balance blocks 6 are uniformly distributed along the circumferential direction of the spring plate 4, as shown in fig. 1, the upper thrust shoe base 9 is in contact with the lower balance block 6, the upper thrust shoe base 9 is fixed by a limit pin 17 on the upper thrust bearing seat 15 in the radial direction, and is fixed by a limit screw 18 on the upper thrust bearing seat 15 in the axial direction, and the upper thrust shoe 10 is embedded in the upper thrust shoe base 9.

As shown in fig. 4, the lower thrust shoe base 11 is mounted in the lower thrust bearing housing 16, the lower thrust shoe 12 is fitted in the lower thrust shoe base 11, and the outer ring gland 14 and the inner ring gland 13 are mounted on the outer diameter side and the inner diameter side of the lower thrust shoe base 11. The inner and outer ring gland is of an annular structure, and outer edges are processed on the outer diameter side and the inner diameter side and used for tightly covering the pads to limit the axial movement of the thrust bearing.

As shown in figure 1, the thrust disc 2 between the upper thrust bearing bush and the lower thrust bearing bush is in a circular truncated cone shape, the contact area between the thrust disc 2 and the upper thrust bearing bush and the contact area between the thrust disc 2 and the lower thrust bearing bush are met, the water storage space of a bearing cavity is increased, and the thrust disc 2 is connected with a rotating shaft 8 of a canned motor pump through a key.