阅读说明：本技术 一种紧凑型航空多级齿轮泵 (Compact aviation multistage gear pump ) 是由 黄啸 高华 王石柱 于 2020-11-27 设计创作，主要内容包括：本发明提出一种紧凑型航空多级齿轮泵。包括壳体,壳体上具有进液口和出液口,壳体内具有第一至第五齿轮副,外部动力通过与第一主齿轮的内花键啮合驱动第一主齿轮转动,第一主齿轮与第一从齿轮啮合传动,第一从齿轮通过内花键与第三主齿轮的右端的外花键啮合,同时,由于第二主齿轮的内花键与第三主齿轮的外花键同步啮合,也驱动第二主齿轮转动,第二主齿轮和第三主齿轮又分别与对应的第二从齿轮和第三从齿轮啮合,第三从齿轮又通过其左端的外花键分别与第四主齿轮和第五主齿轮的内花键啮合,由第三从齿轮带动第四主齿轮和第五主齿轮转动,第四主齿轮与第五主齿轮又分别带动对应的第四从齿轮和第五从齿轮转动。质量轻、体积小、结构紧凑、稳定。(The invention provides a compact aviation multistage gear pump. Comprises a shell, a liquid inlet and a liquid outlet are arranged on the shell, first to fifth gear pairs are arranged in the shell, external power drives a first main gear to rotate by meshing with an internal spline of the first main gear, the first main gear is in meshing transmission with a first driven gear, the first driven gear is in meshing transmission with an external spline at the right end of a third main gear by the internal spline, simultaneously, the internal splines of the second master gear are synchronously meshed with the external splines of the third master gear to drive the second master gear to rotate, the second master gear and the third master gear are respectively meshed with the corresponding second slave gear and the third slave gear, the third slave gear is respectively meshed with the internal splines of the fourth master gear and the fifth master gear through the external splines at the left end, the fourth master gear and the fifth master gear are driven by the third slave gear to rotate, and the fourth master gear and the fifth master gear respectively drive the corresponding fourth slave gear and the fifth slave gear to rotate. Light weight, small volume, compact and stable structure.)

1. Compact aviation multistage gear pump has inlet and liquid outlet including the casing on, the casing, its characterized in that still including being located the casing:

the first gear pair comprises a hollow first main gear and a hollow first driven gear, the right end of the first main gear and the left end of the first driven gear are respectively provided with an internal spline, and the first main gear is in transmission connection with an external driving mechanism through the internal splines;

the second gear pair comprises a hollow second main gear and a second driven gear, and the right end of the second main gear is provided with an internal spline;

the third gear pair comprises a hollow third master gear and a hollow third slave gear, the left ends of the right end of the third master gear and the left end of the third slave gear are long shafts, each long shaft comprises a small-diameter section at the front end and a large-diameter section at the rear end, the small-diameter sections are provided with external splines, the external splines on the small-diameter sections of the third master gear are simultaneously meshed with the internal splines of the first slave gear and the second master gear, the inner diameter of the second master gear is matched with the outer diameter of the large-diameter section of the third master gear in a mutually supporting mode, the left end of the third master gear and the right end of the third slave gear are short shafts with smooth outer surfaces, and the inner diameter of the second slave gear is consistent with the outer diameter of the short shafts of the third slave gear in a mutually supporting mode;

the fourth gear pair comprises a hollow fourth master gear and a fourth slave gear, and the right end of the fourth master gear is provided with an internal spline;

the fifth gear pair comprises a hollow fifth master gear and a fifth slave gear, wherein the right end of the fifth master gear is provided with an internal spline, the internal splines of the fourth master gear and the fifth master gear are simultaneously meshed with an external spline on a small-diameter section of the third slave gear, the inner diameter of a hole at the left end of the fourth master gear is consistent with the outer diameter of a shaft at the right end of the fifth master gear so as to be mutually supported and matched, and the inner diameter of a hole at the left end of the fourth slave gear is consistent with the outer diameter of the shaft at the right end of the fifth slave gear so as to be mutually supported and matched;

a gap is formed between the left end of the first master gear and the right end of the second slave gear, and a gap is formed between the left end of the third master gear and the right end of the fourth slave gear;

the first master gear, the second slave gear, the third slave gear, the fourth master gear and the fifth master gear are coaxially arranged; the first slave gear, the second master gear, the third master gear, the fourth slave gear and the fifth slave gear are coaxially arranged.

2. The compact aviation multistage gear pump of claim 1, wherein a partition is provided between adjacent gear pairs, the partition is in rotary sealing fit with the shaft of the corresponding gear, the partition divides one side of the liquid outlet of each gear pair into five liquid outlet chambers in one-to-one correspondence, each liquid outlet chamber is provided with the liquid outlet correspondingly, cavities on one side of the liquid inlet of each gear pair are communicated with each other, and each cavity is provided with one liquid inlet.

3. The compact aviation multistage gear pump according to claim 1, wherein a partition plate is provided between adjacent gear pairs, the partition plate is in rotary sealing fit with the shaft of the corresponding gear, the partition plate divides one side of the liquid outlet of each gear pair into five liquid outlet chambers in one-to-one correspondence, the liquid outlet is provided on each liquid outlet chamber, an independent first liquid inlet chamber is provided on one side of the liquid inlet of the first gear pair, a first liquid inlet is provided on the first liquid inlet chamber, and the cavities on one sides of the liquid inlets of the second to fifth gear pairs are communicated with each other to form a second liquid inlet chamber, and the cavities have a second liquid inlet.

4. A compact aero multistage gear pump according to claim 2 or 3 wherein the gear pairs of each stage are of different widths.

5. The compact aero multistage gear pump of claim 4, wherein the width of each gear pair progressively decreases.

6. The compact aviation multistage gear pump according to claim 2 or 3, wherein the housing is formed by splicing a plurality of drums with one ends open, the drum bottoms of the drums with drum bottoms located between the adjacent two-stage gear pairs form the partition plate, end covers are arranged at two ends of the housing, and the end covers are fixedly connected with the drums through long screws which are penetrated and installed.

7. A compact aero multistage gear pump according to claim 2 or 3 wherein the intermediate section of the diaphragm is grooved on both sides.

8. The compact aero multistage gear pump according to claim 1, wherein the inlet and outlet ports each have an outward shuttle projection with threaded holes at each end.

9. The compact aviation multistage gear pump of claim 3, wherein the first inlet chamber and the outlet chamber corresponding to the first gear pair are connected to a first channel and a second channel, respectively, the first channel and the second channel are provided with a joint, respectively, and the joint is provided with a valve.

10. The compact aero multistage gear pump according to claim 6, wherein the long screws are correspondingly sleeved with anti-loosening washers.

Technical Field

The invention relates to a compact aviation multistage gear pump.

Background

In the aviation field, plunger pumps are used in various common pumps of aviation propulsion systems, have complex structures and large volumes and weights, and are difficult to realize large flow; the centrifugal pump can not provide required pressure for an engine oil supply device at low rotating speed, and can not meet the requirement of starting rotating speed; the gear pump has the advantages of high pressure, small flow pulsation and the like. However, in the present multi-stage gear pump used in the field of aviation and aerospace, a shaft-through driving manner is mostly adopted, and as shown in fig. 1, a structural schematic diagram of a common shaft-through driving manner is shown in the prior art. This structure not only the space occupies great, can receive a great deal of restriction to the aviation field, and the pivot is for bearing the torsional force, mostly solid construction, and weight is heavier, and multistage location is higher to the part machining precision requirement moreover, the jamming condition often takes place in the assembly process, and also has disconnected axle risk in the use.

Disclosure of Invention

The invention provides a compact aviation multistage gear pump, which aims to solve the technical problems of large axial size, heavy weight and easy clamping stagnation in installation and positioning of the conventional shaft-penetrating driving gear pump.

The technical scheme of the invention is realized as follows: compact aviation multistage gear pump includes the casing, has inlet and liquid outlet on the casing, still including being located the casing:

the first gear pair comprises a hollow first main gear and a hollow first driven gear, the right end of the first main gear and the left end of the first driven gear are respectively provided with an internal spline, and the first main gear is in transmission connection with an external driving mechanism through the internal splines;

the second gear pair comprises a hollow second main gear and a second driven gear, and the right end of the second main gear is provided with an internal spline;

the third gear pair comprises a hollow third master gear and a hollow third slave gear, the left ends of the right end of the third master gear and the left end of the third slave gear are long shafts, each long shaft comprises a small-diameter section at the front end and a large-diameter section at the rear end, the small-diameter sections are provided with external splines, the external splines on the small-diameter sections of the third master gear are simultaneously meshed with the internal splines of the first slave gear and the second master gear, the inner diameter of the second master gear is matched with the outer diameter of the large-diameter section of the third master gear in a mutually supporting mode, the left end of the third master gear and the right end of the third slave gear are short shafts with smooth outer surfaces, and the inner diameter of the second slave gear is consistent with the outer diameter of the short shafts of the third slave gear in a mutually supporting mode;

the fourth gear pair comprises a hollow fourth master gear and a fourth slave gear, and the right end of the fourth master gear is provided with an internal spline;

the fifth gear pair comprises a hollow fifth master gear and a fifth slave gear, wherein the right end of the fifth master gear is provided with an internal spline, the internal splines of the fourth master gear and the fifth master gear are simultaneously meshed with an external spline on a small-diameter section of the third slave gear, the inner diameter of a hole at the left end of the fourth master gear is consistent with the outer diameter of a shaft at the right end of the fifth master gear so as to be mutually supported and matched, and the inner diameter of a hole at the left end of the fourth slave gear is consistent with the outer diameter of the shaft at the right end of the fifth slave gear so as to be mutually supported and matched;

a gap is formed between the left end of the first master gear and the right end of the second slave gear, and a gap is formed between the left end of the third master gear and the right end of the fourth slave gear;

the first master gear, the second slave gear, the third slave gear, the fourth master gear and the fifth master gear are coaxially arranged;

the first slave gear, the second master gear, the third master gear, the fourth slave gear and the fifth slave gear are coaxially arranged.

The technical scheme has the beneficial effects that: the compact aviation multistage gear pump does not need to be provided with a traditional solid transmission shaft, but integrates the functions of the transmission shaft on the gear, and the gear is integrally provided with the hollow shaft tube, so that the compact aviation multistage gear pump has the advantage of light weight; the gear pairs at all levels are mutually sleeved and mutually positioned and supported in a step-by-step transmission mode from the first level to the last level, compared with a traditional integrated shaft penetrating mode, the gear pairs at all levels only need to meet the precision adaptation with the adjacent matched gear pairs, the precision requirement is low, and the traditional shaft penetrating mode requires the precision adaptation of all the gear pairs and the same shaft, so that the processing precision of the traditional mode is high, the precision is difficult to guarantee, and the clamping stagnation and even the shaft breakage are easy to occur; on the other hand, the traditional transmission shaft is not needed to be arranged between each two levels in a supporting and positioning mode, the axial and radial sizes are compact, and the occupied volume and weight are reduced; therefore, the gear pump of this application has advantages such as small, the overall arrangement is compact, light in weight, the stable difficult jamming of stable performance.

On the basis of the scheme, the gear pair structure is further improved in that a partition plate is arranged between adjacent gear pairs and is in rotary sealing fit with the shaft of the corresponding gear, the partition plate divides one side of the liquid outlet of each gear pair into five liquid outlet cavities in one-to-one correspondence, the liquid outlets are correspondingly arranged on the liquid outlet cavities respectively, the cavities on one side of the liquid inlets of the gear pairs are communicated with each other, and each cavity is provided with one liquid inlet.

The technical scheme has the beneficial effects that: the scheme divides a cavity on the liquid outlet side of the five-stage gear pair into five independent cavities, and the five independent cavities are respectively provided with corresponding liquid outlets, so that the five liquid outlets can be respectively connected to different parts or different equipment through pipelines to respectively lubricate or dissipate heat of the five parts or the five equipment, and certainly, certain two or more of the five liquid outlets can be combined from the outside, thereby realizing distribution of different flows; and the cavities between all levels on one side of the liquid inlet are communicated, so that the merging function can be realized, the supply of the same liquid is simpler, the cost is reduced, the damage probability is reduced, and the like.

On the basis of the scheme, the liquid outlet device is further improved in that a partition plate is arranged between adjacent gear pairs and is in rotary sealing fit with a shaft of a corresponding gear, the partition plate divides one side of the liquid outlet of each gear pair into five liquid outlet cavities in one-to-one correspondence, the liquid outlets are correspondingly arranged on the liquid outlet cavities respectively, an independent first liquid inlet cavity is arranged on one side of a liquid inlet of the first gear pair, a first liquid inlet is arranged on the first liquid inlet cavity, cavities on one sides of the liquid inlets of the second gear pair to the fifth gear pair are communicated with each other to form a second liquid inlet cavity, and the cavities are provided with second liquid inlets.

The technical scheme has the beneficial effects that: the scheme is another alternative scheme of the previous scheme, and is different from the previous scheme in that one side of the liquid inlet is divided into four stages, wherein the four stages are communicated, and the other stage is independent, so that the purpose of pumping two different liquids simultaneously can be realized.

On the basis of the scheme, the width of each gear pair is further improved as follows.

The technical scheme has the beneficial effects that: the transmission frequency and the diameter of each gear are consistent, so that the different widths of the gears determine the size of the corresponding pumping flow, the larger the width is, the larger the pumping flow is, the different widths of all stages are different so as to provide pumping functions with various different flows, and the adaptive selection can be carried out according to the requirement of the pumping flow, or the corresponding gear width is designed in advance according to the required flow during the design.

On the basis of the scheme, the width of each gear pair is gradually reduced.

The technical scheme has the beneficial effects that: the purpose of this is to enable the pumped flow to exhibit a gradual decreasing gradient to be readily selected as required.

On the basis of the scheme, the novel gear pair type gear pair power transmission device is further improved in the following mode, the shell is formed by splicing a plurality of drums with openings at one ends, the drum bottoms of the drums with the drum bottoms located between two adjacent stages of gear pairs form the partition plate, the two ends of the shell are end covers, and the end covers are fixedly connected with the drums through long screws which are arranged in a penetrating mode.

The technical scheme has the beneficial effects that: this mode makes things convenient for the dismouting on the one hand, can compress tightly sealed in unison between each level moreover, and on the other hand can increase the grade or subtract the grade as required, and the corresponding long screw rod of length of corresponding change can.

On the basis of the scheme, the novel partition board is further improved in the following way, and grooves are formed in two surfaces of the middle of the partition board.

The technical scheme has the beneficial effects that: on the one hand, the weight can be reduced, and on the other hand, the function of enlarging the volume can be achieved.

On the basis of the scheme, the liquid inlet and the liquid outlet are further improved as follows, wherein outward fusiform bulges are arranged at the liquid inlet and the liquid outlet, and threaded holes are respectively arranged at two ends of the fusiform bulges.

On the basis of the scheme, the liquid inlet and outlet cavities corresponding to the first gear pair are respectively connected with a first channel and a second channel, the first channel and the second channel are respectively provided with a joint, and the joints are provided with valves.

On the basis of the scheme, the anti-loosening device is further improved in the following mode that the long screw rods are correspondingly sleeved with anti-loosening gaskets.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a perspective view (right end first view) of a compact aerial multistage gear pump of the present invention;

FIG. 2 is a perspective view (right end second perspective) of a compact aerial multistage gear pump;

FIG. 3 is a perspective view (left end) of a compact aero multistage gear pump;

FIG. 4 is a schematic longitudinal sectional view of a compact aero multistage gear pump;

FIG. 5 is a longitudinally cut back perspective view of the compact aviation multiple gear pump;

FIG. 6 is a perspective view of each gear pair;

FIG. 7 is a longitudinal sectional view of the gear pair of each stage;

FIG. 8 is a longitudinally cut back perspective view of each gear pair;

fig. 9 is a perspective view of the first main gear;

fig. 10 is a perspective view of the second main gear;

fig. 11 is a perspective view of a third main gear;

fig. 12 is a perspective view of a fourth main gear;

FIG. 13 is a longitudinal cut-away rear perspective view of each gear pair (cut along a section plane perpendicular to FIG. 8);

wherein: a-first gear pair, A1-first master gear, A2-first slave gear, B-second gear pair, B1-second master gear, B2-second slave gear, C-third gear pair, C1-third master gear, C2-third slave gear, D-fourth gear pair, D1-fourth master gear, D2-fourth slave gear, E-fifth gear pair, E1-fifth master gear, E2-fifth slave gear, 1-end cap, 2-partition, 21-groove, 3-joint, 41-first inlet, 42-second inlet, 5-outlet, 6-shuttle-projection, 7-joint, 8-long screw, 9-anti-loose shim, 12-internal spline, 13-external spline, 14-long shaft, 15-small diameter section, 16-large diameter section and S-gap.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention relates to a specific embodiment of a compact aviation multistage gear pump, which comprises the following steps: as shown in fig. 1-3, the compact aviation multistage gear pump comprises a housing having an inlet and an outlet, and as shown in fig. 4, further comprises first to fifth gear pairs (a-E) located in the housing, the first gear pair a comprises a hollow first master gear a1 and a first slave gear a2, the right end of the first master gear a1 and the left end of the first slave gear a2 respectively have internal splines 12, and the first master gear a1 is in transmission connection with an external driving mechanism through the internal splines 12. The second gear set B comprises a hollow second master gear B1 and a second slave gear B2, the right end of the second master gear B1 has internal splines 12. The third gear pair C comprises a hollow third master gear C1 and a third slave gear C2, the right end of the third master gear C1 and the left end of the third slave gear C2 are long shafts 14, the long shafts 14 comprise a small diameter section 15 at the front end and a large diameter section 16 at the rear end, external splines 13 are arranged on the small diameter section 15, the external splines 13 on the small diameter section 15 of the third master gear C1 are simultaneously meshed with the internal splines 12 of the first slave gear a2 and the second master gear B1, the inner diameter of the second master gear B1 is in supporting fit with the outer diameter of the large diameter section 16 of the third master gear C1, the left end of the third master gear C1 and the right end of the third slave gear C2 are short shafts with smooth outer surfaces, and the inner diameter of the second slave gear B2 is in supporting fit with the outer diameter of the short shaft of the third slave gear C2. The fourth gear pair D comprises a hollow fourth master gear and a fourth slave gear, and the right end of the fourth master gear has an internal spline 12. The fifth gear pair E comprises a hollow fifth master gear E1 and a fifth slave gear E2, the right end of the fifth master gear E1 is provided with an internal spline 12, the internal spline 12 of the fourth and fifth master gears E1 is simultaneously meshed with an external spline 13 on a small diameter section 15 of the third slave gear C2, the inner diameter of the hole of the left end of the fourth master gear is consistent with the outer diameter of the shaft at the right end of the fifth master gear E1 so as to be mutually supported and matched, and the inner diameter of the hole of the left end of the fourth slave gear is consistent with the outer diameter of the shaft at the right end of the fifth slave gear E2 so as to be mutually supported and matched. A gap S is provided between the left end of the first master gear a1 and the right end of the second slave gear B2, and a gap S is provided between the left end of the third master gear C1 and the right end of the fourth slave gear. A first master gear a1, a second slave gear B2, a third slave gear C2, a fourth master gear and a fifth master gear E1 are coaxially disposed; the first slave gear a2, the second master gear B1, the third master gear C1, the fourth slave gear, and the fifth slave gear E2 are coaxially disposed.

As shown in fig. 4, wherein both ends of the first master gear a1 and the first slave gear a2 are sleeved with circular rings, the circular rings are embedded in corresponding circular holes of the end cap 1 and the first barrel 3, so that the first master gear a1 and the first slave gear a2 can be stably positioned and can freely rotate; the first master gear a1 and the first slave gear a2 are also provided with a barrel-shaped seal retainer adjacent the internal splines 12.

The transmission process is as follows: an external power (such as a motor) drives the first master gear A1 to rotate by meshing with the internal splines 12 at the right end of the first master gear A1, the first master gear A1 is in meshing transmission with the first slave gear A2 to drive the first slave gear A2 to rotate, the first slave gear A2 is in meshing transmission with the external splines 13 at the right end of the third master gear C1 by the internal splines 12 at the left end thereof to drive the third master gear C1 to rotate, meanwhile, the second master gear B1 is also driven to rotate due to the synchronous meshing of the internal splines 12 of the second master gear B1 with the external splines 13 of the third master gear C1, the second master gear B1 and the third master gear C1 are in turn in meshing transmission with the corresponding second slave gear B2 and the third slave gear C2 to drive the second slave gear B2 and the third slave gear C2, and the third slave gear C2 is in meshing transmission with the internal splines 12 of the fourth master gear E1, therefore, the fourth master gear and the fifth master gear E1 are driven by the third slave gear C2 to rotate, and the fourth master gear and the fifth master gear E1 respectively drive the corresponding fourth slave gear and the fifth slave gear E2 to rotate, so that the whole moving process is realized.

The compact aviation multistage gear pump does not need to be provided with a traditional solid transmission shaft, but integrates the functions of the transmission shaft on the gear, and the gear is integrally provided with the hollow shaft tube, so that the compact aviation multistage gear pump has the advantage of light weight; the gear pairs at all levels are mutually sleeved and mutually positioned and supported in a step-by-step transmission mode from the first level to the last level, compared with a traditional integrated shaft penetrating mode, the gear pairs at all levels only need to meet the precision adaptation with the adjacent matched gear pairs, the precision requirement is low, and the traditional shaft penetrating mode requires the precision adaptation of all the gear pairs and the same shaft, so that the processing precision of the traditional mode is high, the precision is difficult to guarantee, and the clamping stagnation and even the shaft breakage are easy to occur; on the other hand, the traditional transmission shaft is not needed to be arranged between each two levels in a supporting and positioning mode, the axial and radial sizes are compact, and the occupied volume and weight are reduced; therefore, the gear pump of this application has advantages such as small, the overall arrangement is compact, light in weight, the stable difficult jamming of stable performance.

As shown in fig. 4, 5, and 13, a partition plate 2 is provided between adjacent gear pairs, the partition plate 2 is in rotary sealing fit with the shaft of the corresponding gear, the partition plate 2 divides one side of the liquid outlet 5 of each gear pair into five liquid outlet chambers in one-to-one correspondence, each liquid outlet chamber is correspondingly provided with a liquid outlet 5, one side of the liquid inlet of the first gear pair a is provided with an independent first liquid inlet chamber, the first liquid inlet chamber is provided with a first liquid inlet 41, the cavities on one side of the liquid inlets of the second to fifth gear pairs are communicated with each other to form a second liquid inlet chamber, and the cavities are provided with a second liquid inlet 42. One side of the liquid inlet is divided into four stages, wherein the four stages are communicated, and the other stage is independent, so that the aim of pumping two different liquids simultaneously can be fulfilled.

In other embodiments, the alternative scheme is as follows, a partition plate 2 is arranged between adjacent gear pairs, the partition plate 2 is in rotary sealing fit with the shaft of the corresponding gear, the partition plate 2 divides one side of the liquid outlet 5 of each gear pair into five liquid outlet cavities in one-to-one correspondence, the liquid outlet 5 is correspondingly arranged on each liquid outlet cavity, the cavities at one side of the liquid inlet of each gear pair are communicated with each other, and the cavity is provided with a liquid inlet. The scheme divides a cavity on the liquid outlet side of the five-stage gear pair into five independent cavities, and the five independent cavities are respectively provided with the corresponding liquid outlets 5, so that the five liquid outlets 5 can be respectively connected to different parts or different equipment through pipelines to respectively lubricate or dissipate heat of the five parts or the five equipment, certainly, certain two paths or multiple paths can be combined from the outside, thereby realizing distribution of different flow rates, and at the moment, the equipment is divided into more paths due to the arrangement of the partition plates 2 and has the function of multi-path distribution; and the cavities between all levels on one side of the liquid inlet are communicated, so that the merging function can be realized, the supply of the same liquid is simpler, the cost is reduced, the damage probability is reduced, and the like.

As shown in fig. 4, 5, and 13, in the present embodiment, the width of each gear pair is different. The transmission frequency and the diameter of each gear are consistent, so that the different widths of the gears determine the size of the corresponding pumping flow, the larger the width is, the larger the pumping flow is, the different widths of all stages are different so as to provide pumping functions with various different flows, and the adaptive selection can be carried out according to the requirement of the pumping flow, or the corresponding gear width is designed in advance according to the required flow during the design. The width of each gear pair is gradually decreased. The purpose of this is to enable the pumped flow to exhibit a gradual decreasing gradient to be readily selected as required. The casing is formed by the concatenation of a plurality of one end open-ended casks 3, and the barrel head lies in the barrel head of the cask 3 between the adjacent two-stage gear pair and constitutes baffle 2, the both ends of casing are end cover 1, and end cover 1 is connected fixedly through the long screw 8 of wearing the dress with each cask 3. This mode makes things convenient for the dismouting on the one hand, can compress tightly sealed in unison between each grade moreover, and on the other hand can increase the grade or subtract the grade as required, and the corresponding long screw 8 of length can be changed to the correspondence. Two sides of the middle part of the clapboard 2 are provided with grooves 21. On the one hand, the weight can be reduced, and on the other hand, the function of enlarging the volume can be achieved. The liquid inlet and the liquid outlet 5 are both provided with outward fusiform bulges 6, and both ends of the fusiform bulges 6 are respectively provided with a threaded hole. A first liquid inlet cavity and a liquid outlet cavity corresponding to the first gear pair A are respectively connected with a first channel and a second channel, the first channel and the second channel are respectively provided with a joint 7, and the joint 7 is provided with a valve. The long screw 8 is correspondingly sleeved with a locking gasket 9.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.