CN220415678U - Non-full-tooth even-cavity low-pulsation cycloid pump - Google Patents

Abstract

The utility model relates to a non-full-tooth even-cavity low-pulsation cycloid pump, belonging to the technical field of cycloid pumps; the pump comprises a pump body, a pump cover is arranged at an opening at one end of the pump body, the pump cover and the pump body are fixedly connected to a host through bolts, an outer rotor and an inner rotor are arranged in the pump body, the outer rotor is sleeved on the outer side of the inner rotor, the outer rotor is rotationally connected in the pump body, an outer transmission shaft is inserted from the opening at one side of the pump body far away from the pump cover and extends into the inner rotor, the inner rotor is connected with the outer transmission shaft through five groups of involute splines which are uniformly arranged, the number of inner teeth of the outer rotor is eleven teeth, the number of outer teeth of the inner rotor is ten teeth, and the tooth shapes of the inner teeth and the outer teeth are cycloid tooth shapes; solves the problems of larger pulsation, low structural strength, large noise and unstable output oil of the existing odd-cavity cycloid pump.

Description

Non-full-tooth even-cavity low-pulsation cycloid pump

Technical Field

The utility model belongs to the technical field of cycloidal pumps, and particularly relates to a non-full-tooth even-cavity low-pulsation cycloidal pump.

Background

As shown in fig. 1, the existing cycloidal lubrication pump comprises a pump body 1 and a pump cover 2, wherein the pump cover 2 is arranged at an opening at one end of the pump body 1, a sealing ring 6 is arranged between the pump cover 2 and the pump body 1, and the sealing ring 6 is arranged in a sealing groove at the opening at one end of the pump body 1. The pump cover 2 and the pump body 1 are fixedly connected to the host through bolts. An outer rotor 3 and an inner rotor 4 are arranged in the pump body 1, the outer rotor 3 is sleeved on the outer side of the inner rotor 4, fourteen inner teeth are arranged on the outer rotor 3, thirteen outer teeth are arranged on the inner rotor 4, and the outer rotor 3 and the inner rotor 4 are eccentrically arranged and are in tooth-shaped meshing close contact. The outer rotor 3 is rotatably connected inside the pump body 1, and a half-moon-shaped oil suction port 10 and a half-moon-shaped oil pressing port 9 are arranged at the bottom of the pump body 1. An outer driving shaft 5 is inserted in the inner rotor 4, the outer driving shaft 5 is inserted from an opening of one side of the pump body 1 far away from the pump cover 2 and extends into the inner rotor 4, and the inner rotor 4 is sleeved on the outer side of the outer driving shaft 5 through a single key. When the inner rotor 4 rotates together with the outer transmission shaft 5, ten or eleven sealed oil chambers are formed between the inner rotor 4 and the outer rotor 3 under cycloidal tooth engagement.

As shown in fig. 2, when the outer transmission shaft 5 drives the inner rotor 4 to rotate clockwise, the inner rotor 4 and the outer rotor 3 form six high-pressure oil cavities 11 and five low-pressure oil cavities 12, the sum of the instantaneous flow rates of all the oil cavities of the same instantaneous high-pressure oil cavity 11 is larger than the sum of the instantaneous flow rates of all the oil cavities of the low-pressure oil cavity 12, the output flow rate non-uniformity coefficient is overlarge, the flow rate pressure pulsation is larger, and the pressure oil is unstable.

The end face of the inner rotor 4 is provided with a lubrication hole 7, a hollow lubrication groove 8 along the circumferential direction is arranged at the inner ring, the structural strength is reduced, and the bearing torque is small.

The inner rotor 4 inner circle sets up the single bond, and outer drive shaft 5 clockwise rotation, inner rotor 4 receives anticlockwise moment of torsion, and inner rotor 4 inner circle single bond atress only in a tooth department, and radial unbalance, outer excitation under rotatory in-process inner rotor 4 produce vibration, and the vibration counteracts hydraulic oil, forms the reflection wave and transmits to pressure source department, and pulsation superposes each other and produces the standing wave of harm bigger, and output fluid is unstable. Therefore, the noise of the oil pump is reduced, the pulsation flow is reduced, and the product quality is continuously improved.

Disclosure of Invention

The utility model overcomes the defects of the prior art and provides a non-full-tooth even-cavity low-pulsation cycloid pump; solves the problems of larger pulsation, low structural strength, large noise and unstable output oil of the existing odd-cavity cycloid pump.

In order to achieve the above purpose, the present utility model is realized by the following technical scheme.

The utility model provides a low pulsation cycloid pump in non-full tooth even number chamber, including the pump body, the pump cover sets up in the one end opening part of pump body, pump cover and pump body pass through bolt fixed connection on the host computer, be provided with the external rotor in the pump body inside, the internal rotor, the external rotor cup joints in the outside of internal rotor, the external rotor rotates to be connected in the pump body inside, the outside drive axle is kept away from the one side opening part of pump cover from the pump body and is inserted and stretch into to the internal rotor inside, the internal rotor is connected through five sets of involute spline that evenly set up with the outside drive axle, the internal tooth quantity of external rotor is eleven teeth, the external tooth quantity of internal rotor is ten teeth, the profile of internal tooth and external tooth is cycloid profile.

Further, a sealing ring is arranged between the pump cover and the pump body, and the sealing ring is arranged in a sealing groove at an opening at one end of the pump body.

Further, five sections of involute splines are uniformly arranged on the inner side surface of the inner rotor along the peripheral ring, and five sections of involute splines are uniformly arranged on the outer side surface of the outer transmission shaft along the peripheral ring, and the involute splines on the inner rotor and the involute splines on the outer transmission shaft are in one-to-one correspondence and meshed with each other.

Further, a vacancy is arranged between two adjacent involute splines on the inner rotor, a vacancy is arranged between two adjacent involute splines on the outer transmission shaft, the vacancies on the inner rotor and the vacancies on the outer transmission shaft are in one-to-one correspondence and form a complete and airtight lubrication groove, and five lubrication grooves are formed between the inner rotor and the outer transmission shaft.

Further, five sections of involute splines on the inner side surface of the inner rotor are respectively arranged corresponding to five external teeth of the inner rotor, five empty spaces between the five sections of involute splines on the inner side surface of the inner rotor are respectively arranged corresponding to the remaining five external teeth of the inner rotor, and five external teeth corresponding to the five sections of involute splines and five external teeth corresponding to the five empty spaces are respectively and alternately arranged.

Further, the outer rotor is eccentrically disposed with the inner rotor, and the outer teeth of the inner rotor are in close contact with the inner teeth of the outer rotor.

Further, an oil distribution window is arranged at the inner bottom surface of the pump body, the oil distribution window comprises an oil suction port and an oil pressing port, the oil suction port and the oil pressing port are of semi-annular structures, and the oil suction port and the oil pressing port are coaxially arranged; the upper end edge of the oil suction port and the upper end edge of the oil pressing port are kept at intervals, and the lower end edge of the oil suction port and the lower end edge of the oil pressing port are kept at intervals.

Further, when the outer driving shaft drives the inner rotor to rotate to the first limit position, a groove between two inner teeth at the top of the outer rotor is formed between the upper end edge of the oil suction port and the upper end edge of the oil pressing port, and one inner tooth at the bottom of the outer rotor is formed between the lower end edge of the oil suction port and the lower end edge of the oil pressing port; the top ends of the two external teeth of the top part of the inner rotor are respectively contacted with the top ends of the two internal teeth of the top part of the outer rotor, and a transition cavity is formed by a groove between the two external teeth of the top part of the inner rotor and a groove between the two internal teeth of the top part of the outer rotor; grooves on two sides of the inner teeth at the bottom of the outer rotor are respectively and completely meshed with two outer teeth at the bottom of the inner rotor; the area of the outer rotor meshed with the inner rotor forms four independent low-pressure oil cavities at the oil suction port, and the area of the outer rotor meshed with the inner rotor forms four independent high-pressure oil cavities at the oil pressing port.

Further, when the inner rotor rotates to the transition position, the transition cavity at the first limit position is communicated with the oil port to form a new high-pressure oil cavity, and the high-pressure oil cavity at the lowest end at the first limit position disappears due to the mutual engagement of the inner rotor and the outer rotor, so that four low-pressure oil cavities and four high-pressure oil cavities are formed between the inner rotor and the outer rotor.

Further, when the inner rotor rotates to the second limit position, an inner tooth at the top of the outer rotor is arranged between the upper end edge of the oil suction port and the upper end edge of the oil pressing port, and a groove is arranged between the lower end edge of the oil suction port and the lower end edge of the oil pressing port and between the two inner teeth at the bottom of the outer rotor; the top end of the external teeth at the top of the inner rotor is contacted with the top end of the internal teeth at the top of the outer rotor, and the external teeth at the bottom of the inner rotor are completely meshed with grooves between the two internal teeth at the bottom of the outer rotor; the area of the outer rotor meshed with the inner rotor forms four independent low-pressure oil cavities at the oil suction port, and the area of the outer rotor meshed with the inner rotor forms four independent high-pressure oil cavities at the oil pressing port.

Compared with the prior art, the utility model has the following beneficial effects: through improving the part design, change moving part natural frequency, pressure pulsation source frequency keeps away from moving part natural frequency, and pressure liquid flow fluctuation tends to be steady, and the adaptability to the load is improved, and the noise is improved, and oil pump performance test promotes, and production efficiency is high, promotes the increase of enterprise benefit.

Drawings

The utility model is described in further detail below with reference to the accompanying drawings:

FIG. 1 is a schematic illustration of a gerotor pump configuration;

FIG. 2 is a schematic illustration of the operation of a prior art odd chamber gerotor pump;

FIG. 3 is a schematic representation of the operation of the present utility model in a first extreme position;

FIG. 4 is a schematic representation of the operation of the present utility model in a transitional position;

FIG. 5 is a schematic representation of the operation of the present utility model in a second extreme position;

the pump comprises a pump body 1, a pump cover 2, an outer rotor 3, an inner rotor 4, an outer transmission shaft 5, a sealing ring 6, a lubrication hole 7, a lubrication groove 8, an oil pressing port 9, an oil suction port 10, a high-pressure oil cavity 11, a low-pressure oil cavity 12, a transition oil cavity 13, an involute spline 14, support teeth 15, a first high-pressure oil cavity 16 and a first low-pressure oil cavity 17.

Detailed Description

In order to make the technical problems, technical schemes and beneficial effects to be solved more clear, the utility model is further described in detail by combining the embodiments and the drawings. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the utility model. The following describes the technical scheme of the present utility model in detail with reference to examples and drawings, but the scope of protection is not limited thereto.

As shown in fig. 3, 4 and 5, the utility model provides a non-full-tooth even-cavity low-pulsation cycloid pump, which comprises a pump body 1 and a pump cover 2, wherein the pump cover 2 is arranged at an opening at one end of the pump body 1, a sealing ring 6 is arranged between the pump cover 2 and the pump body 1, and the sealing ring 6 is arranged in a sealing groove at the opening at one end of the pump body 1. The pump cover 2 and the pump body 1 are fixedly connected to the host through bolts.

An outer rotor 3 and an inner rotor 4 are arranged inside the pump body 1, the outer rotor 3 is sleeved on the outer side of the inner rotor 4, and the outer rotor 3 is rotatably connected inside the pump body 1. An outer driving shaft 5 is inserted into the inner rotor 4, and the outer driving shaft 5 is inserted from an opening of one side of the pump body 1 away from the pump cover 2 and extends into the inner rotor 4.

The number of internal teeth of the outer rotor 3 is eleven teeth, the number of external teeth of the inner rotor 4 is ten teeth, and the tooth shapes of the internal teeth and the external teeth are cycloid tooth shapes.

Five sections of involute splines 14 are uniformly arranged on the inner side surface of the inner rotor 4 along the circumference, five sections of involute splines 14 are uniformly arranged on the outer side surface of the outer transmission shaft 5 along the circumference, the involute splines 14 on the inner rotor 4 are in one-to-one correspondence with and meshed with the involute splines 14 on the outer transmission shaft 5, and the outer transmission shaft 5 drives the inner rotor 4 to synchronously rotate through the five groups of meshed involute splines 14. Gaps are arranged between two adjacent involute splines 14 on the inner rotor 4, gaps are arranged between two adjacent involute splines 14 on the outer transmission shaft 5, the gaps on the inner rotor 4 and the gaps on the outer transmission shaft 5 are in one-to-one correspondence, a complete and airtight lubrication groove 8 is formed, and five lubrication grooves 8 are formed between the inner rotor 4 and the outer transmission shaft 5.

Five sections of involute splines 14 on the inner side surface of the inner rotor 4 are respectively arranged corresponding to five external teeth of the inner rotor 4, five empty spaces between the five sections of involute splines 14 on the inner side surface of the inner rotor 4 are respectively arranged corresponding to the remaining five external teeth of the inner rotor 4, and five external teeth corresponding to the five sections of involute splines 14 and five external teeth corresponding to the five empty spaces are respectively and alternately arranged.

The outer rotor 3 is eccentrically disposed with the inner rotor 4, and the outer teeth of the inner rotor 4 are in close contact with the inner teeth of the outer rotor 3.

An oil distribution window is arranged on the inner bottom surface of the pump body 1 and comprises an oil suction port 10 and an oil pressing port 9, the oil suction port 10 and the oil pressing port 9 are of semi-annular structures, and the oil suction port 10 and the oil pressing port 9 are coaxially arranged. A space is kept between the upper end edge of the oil suction port 10 and the upper end edge of the pressure oil port 9, and a space is kept between the lower end edge of the oil suction port 10 and the lower end edge of the pressure oil port 9.

When the outer transmission shaft 5 drives the inner rotor 4 to rotate to the first limit position in fig. 3, a groove between two inner teeth at the top of the outer rotor 3 is arranged between the upper end edge of the oil suction port 10 and the upper end edge of the pressure oil port 9, and one inner tooth at the bottom of the outer rotor 3 is arranged between the lower end edge of the oil suction port 10 and the lower end edge of the pressure oil port 9. The two external tooth top ends at the top of the inner rotor 4 are respectively contacted with the two internal tooth top ends at the top of the outer rotor 3, and a transition oil cavity 13 is formed by a groove between the two external teeth at the top of the inner rotor 4 and a groove between the two internal teeth at the top of the outer rotor 3. Grooves on two sides of the inner teeth at the bottom of the outer rotor 3 are respectively and completely meshed with two outer teeth at the bottom of the inner rotor 4. The area of the outer rotor 3 meshed with the inner rotor 4 forms four independent low-pressure oil cavities 12 at the oil suction port 10, and the area of the outer rotor 3 meshed with the inner rotor 4 forms four independent high-pressure oil cavities 11 at the oil pressure port 9.

The outer transmission shaft 5 drives the inner rotor 4 to continue rotating, when the inner rotor 4 rotates to the transition position in fig. 4, the transition oil cavity 13 at the first limit position is communicated with the pressure oil port 9 to form a new high-pressure oil cavity 11, and the high-pressure oil cavity 11 at the lowest end at the first limit position disappears due to the mutual engagement of the inner rotor 4 and the outer rotor 3, so that four low-pressure oil cavities 12 and four high-pressure oil cavities 11 are formed between the inner rotor 4 and the outer rotor 3.

When the inner rotor 4 rotates to the second limit position in fig. 5, an inner tooth at the top of the outer rotor 3 is arranged between the upper end edge of the oil suction port 10 and the upper end edge of the pressure oil port 9, and a groove is arranged between the lower end edge of the oil suction port 10 and the lower end edge of the pressure oil port 9 and between the two inner teeth at the bottom of the outer rotor 3. The top ends of the external teeth at the top of the inner rotor 4 are contacted with the top ends of the internal teeth at the top of the outer rotor 3, and the external teeth at the bottom of the inner rotor 4 are completely meshed with grooves between the two internal teeth at the bottom of the outer rotor 3. The area of the outer rotor 3 meshed with the inner rotor 4 forms four independent low-pressure oil cavities 12 at the oil suction port 10, and the area of the outer rotor 3 meshed with the inner rotor 4 forms four independent high-pressure oil cavities 11 at the oil pressure port 9.

The process from fig. 3 to fig. 5 completes a cycloidal tooth oil absorption process.

The inner rotor 4 has ten external teeth, and oil is absorbed by the cycloid teeth for ten times. The pulsation frequency of the pressure hydraulic oil is determined by the rotation speed of the outer transmission shaft 5, the number of teeth of the inner rotor 4 and the ratio of the number of the high cavity to the number of the low cavity.

When the inner rotor 4 drives the outer rotor 3 to rotate to the first limit position as shown in fig. 3, the symmetrical number of the left and right oil cavities is equal, four low-pressure oil cavities 12 and four high-pressure oil cavities 11 are respectively formed, and eight working cavities are formed, so that the number of the high-pressure oil cavities 11 and the number of the low-pressure oil cavities 12 are even and equal.

The area between the upper end of the oil suction port 10 and the upper end of the oil pressing port 9 at the bottom of the pump body 1 is an oil sealing area, and the size of the oil sealing area is determined by an oil sealing angle a. If the oil sealing angle a is too small, the first high-pressure oil cavities 16 and the first low-pressure oil cavities 17 at the uppermost ends of the two sides are mutually communicated, high-pressure oil can instantaneously flow back from the first high-pressure oil cavities 16 to the inside of the first low-pressure oil cavities 17, eight oil cavities in each working period rotate to pass through the oil sealing area, and therefore periodic high-pressure backflow is formed, output flow and pressure pulsation are caused, and hydraulic impact is formed. By reasonably designing the oil sealing angle a (40-50 degrees), the first high-pressure oil cavity 16 and the first low-pressure oil cavity 17 are not communicated with each other at the transition position in fig. 4, and pressure pulsation is not generated.

When the inner rotor 4 drives the outer rotor 3 to rotate to the transition position shown in fig. 4, the volume of the oil cavity is changed from large to small, an oil suction and pressing oil circulation is completed, the oil has a certain compressibility, just like a hydraulic spring, energy is stored when the oil is pressed, energy is released when the oil is pressed, and the flowing liquid forms a pressure gradient, so that the pressure pulsation source is formed. Each tooth of the pressure pulsation cycloid pump participates in meshing, but not every tooth can form an effective oil absorption oil cavity. The periodical pressure pulsation is generated, the flow pressure pulsation is low when the number of the same flow pressure pulsation is low and the flow pressure pulsation is large when the number of the same flow pressure pulsation is different depending on the number ratio of the high oil cavity to the low oil cavity at the instant position. As in fig. 4, when the transition chamber is rotated to communicate with the high-pressure oil chamber 11, the two internal teeth of the outer rotor 3 are completely engaged with the external teeth of the inner rotor 4, and the number of the supporting teeth 15 on the outer rotor 3 is two, so that the number of the high-pressure oil chambers 11 and the number of the low-pressure oil chambers 12 are even and equal. The oil is dynamically balanced in the rotation direction, and the pressure pulsation is small.

When the inner rotor 4 drives the outer rotor 3 to rotate to a second limit position as shown in fig. 5, a cavity is always communicated with high pressure and a cavity is communicated with low pressure in an oil sealing area corresponding to the oil sealing angle a; meanwhile, two inner teeth of the outer rotor 3 are completely meshed with outer teeth of the inner rotor 4, two supporting teeth 15 are arranged between the outer rotor 3 and the inner rotor 4, so that four high-pressure oil cavities 11 and four low-pressure oil cavities 12 are formed, the four high-pressure oil cavities 11 and the four low-pressure oil cavities 12 respectively form an oil absorption area and an oil pressing area which are independently sealed, and the number of the high-pressure oil cavities 11 and the number of the low-pressure oil cavities 12 are equal and even.

As shown in fig. 4, when the inner ring of the inner rotor 4 is provided with the segmented involute spline 14, the involute spline 14 and the empty space are alternately arranged and uniformly correspond to the inner ring of the inner rotor 4, oil uniformly flows through the empty space, the contact surface is well lubricated, the tooth profile of the involute spline 14 is uniformly stressed, the inner side surface of the inner rotor 4 is not provided with a hollow groove, the structural strength is enhanced, and the bearing torque is large.

As shown in fig. 4, when the involute spline 14 is disposed on the inner ring of the inner rotor 4, the tooth shape of the involute spline 14 is uniformly distributed on the inner ring, the outer driving shaft 5 rotates clockwise, the inner rotor 4 is subjected to counterclockwise torque, the load is uniformly dispersed, tiny vibration is generated in the process that the inner rotor 4 is subjected to external excitation rotation, the tiny vibration reacts on hydraulic oil to form reflected waves, the wave frequency is n-order natural frequency of the inner rotor 4, the wave frequency is far away from the excitation frequency, the output pressure wave and the excitation source do not generate resonance, and the output oil pulsation is reduced.

Through the structure of the inner rotor 4 of reasonable design, every tooth of inner rotor 4 and outer rotor 3 can both form four high pressure oil chamber 11 and four low pressure oil chamber 12 in extreme position, intermediate position, and the rotation receives even hydraulic pressure when arbitrary instantaneous position. The inner ring spline not only has reliable transmission, but also has good lubrication, the inner rotor and the outer rotor 3 run stably, the reflected wave is weakened, and the pulsation of hydraulic oil is small. The noise reduction effect is greatly improved, and the work is more reliable.

It will be evident to those skilled in the art that the utility model is not limited to the details of the foregoing illustrative embodiments, and that the present utility model may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the utility model being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Claims (10)

1. A non-full tooth even number chamber low pulsation cycloid pump which characterized in that: including pump body (1), pump cover (2) set up in the one end opening part of pump body (1), pump cover (2) are connected on the host computer through bolt fixed connection with pump body (1), be provided with external rotor (3) inside pump body (1), internal rotor (4), external rotor (3) cup joint in the outside of internal rotor (4), external rotor (3) rotate and connect in pump body (1) inside, one side opening part that pump cover (2) was kept away from to pump body (1) is inserted and is stretched into inside internal rotor (4) in outer drive shaft (5), internal rotor (4) are connected through involute spline (14) of five groups evenly setting with outer drive shaft (5), internal tooth quantity of external rotor (3) is eleven teeth, the external tooth quantity of internal rotor (4) is ten teeth, the profile of tooth and external tooth is cycloid profile.

2. The non-full-tooth even-cavity low-pulsation gerotor pump of claim 1, wherein: a sealing ring (6) is arranged between the pump cover (2) and the pump body (1), and the sealing ring (6) is arranged in a sealing groove at an opening at one end of the pump body (1).

3. The non-full-tooth even-cavity low-pulsation gerotor pump of claim 1, wherein: five-section involute splines (14) are uniformly arranged on the inner side surface of the inner rotor (4) along the circumference, five-section involute splines (14) are uniformly arranged on the outer side surface of the outer transmission shaft (5) along the circumference, and the involute splines (14) on the inner rotor (4) are in one-to-one correspondence with and meshed with the involute splines (14) on the outer transmission shaft (5).

4. A non-full-tooth even-cavity low-pulsation gerotor pump of claim 3, wherein: gaps are arranged between two adjacent involute splines (14) on the inner rotor (4), gaps are arranged between two adjacent involute splines (14) on the outer transmission shaft (5), the gaps on the inner rotor (4) are in one-to-one correspondence with the gaps on the outer transmission shaft (5) and form a complete and airtight lubrication groove (8), and five lubrication grooves (8) are formed between the inner rotor (4) and the outer transmission shaft (5).

5. The non-full-tooth even-cavity low-pulsation gerotor pump of claim 4, wherein: five sections of involute splines (14) on the inner side surface of the inner rotor (4) are respectively arranged corresponding to five external teeth of the inner rotor (4), five empty spaces between the five sections of involute splines (14) on the inner side surface of the inner rotor (4) are respectively arranged corresponding to the remaining five external teeth of the inner rotor (4), and five external teeth corresponding to the five sections of involute splines (14) and five external teeth corresponding to the five empty spaces are respectively arranged alternately.

6. The non-full-tooth even-cavity low-pulsation gerotor pump of claim 1, wherein: the outer rotor (3) is eccentrically arranged with the inner rotor (4), and the outer teeth of the inner rotor (4) are in close contact with the inner teeth of the outer rotor (3).

7. The non-full-tooth even-cavity low-pulsation gerotor pump of claim 1, wherein: an oil distribution window is arranged at the inner bottom surface of the pump body (1), the oil distribution window comprises an oil suction port (10) and an oil pressing port (9), the oil suction port (10) and the oil pressing port (9) are of semi-annular structures, and the oil suction port (10) and the oil pressing port (9) are coaxially arranged; the upper end edge of the oil suction port (10) and the upper end edge of the pressure oil port (9) are kept at intervals, and the lower end edge of the oil suction port (10) and the lower end edge of the pressure oil port (9) are kept at intervals.

8. The non-full-tooth even-cavity low-pulsation gerotor pump of claim 1, wherein: when the outer transmission shaft (5) drives the inner rotor (4) to rotate to a first limit position, a groove between two inner teeth at the top of the outer rotor (3) is arranged between the upper end edge of the oil suction port (10) and the upper end edge of the pressure oil port (9), and one inner tooth at the bottom of the outer rotor (3) is arranged between the lower end edge of the oil suction port (10) and the lower end edge of the pressure oil port (9); the top ends of the two external teeth on the top of the inner rotor (4) are respectively contacted with the top ends of the two internal teeth on the top of the outer rotor (3), and a transition cavity is formed by a groove between the two external teeth on the top of the inner rotor (4) and a groove between the two internal teeth on the top of the outer rotor (3); grooves on two sides of the inner teeth at the bottom of the outer rotor (3) are respectively and completely meshed with two outer teeth at the bottom of the inner rotor (4); four independent low-pressure oil cavities (12) are formed at the oil suction port (10) in the area where the outer rotor (3) is meshed with the inner rotor (4), and four independent high-pressure oil cavities (11) are formed at the oil pressing port (9) in the area where the outer rotor (3) is meshed with the inner rotor (4).

9. The non-full-tooth even-cavity low-pulsation gerotor pump of claim 8, wherein: when the inner rotor (4) rotates to the transition position, the transition cavity at the first limit position is communicated with the pressure oil port (9) to form a new high-pressure oil cavity (11), and the high-pressure oil cavity (11) at the lowest end at the first limit position disappears due to the mutual engagement of the inner rotor (4) and the outer rotor (3), so that four low-pressure oil cavities (12) and four high-pressure oil cavities (11) are formed between the inner rotor (4) and the outer rotor (3).

10. The non-full-tooth even-cavity low-pulsation gerotor pump of claim 9, wherein: when the inner rotor (4) rotates to a second limit position, an inner tooth at the top of the outer rotor (3) is arranged between the upper end edge of the oil suction port (10) and the upper end edge of the pressure oil port (9), and a groove is arranged between the lower end edge of the oil suction port (10) and the lower end edge of the pressure oil port (9) and between the two inner teeth at the bottom of the outer rotor (3); the top end of the external teeth at the top of the inner rotor (4) is contacted with the top end of the internal teeth at the top of the outer rotor (3), and the external teeth at the bottom of the inner rotor (4) are completely meshed with grooves between the two internal teeth at the bottom of the outer rotor (3); four independent low-pressure oil cavities (12) are formed at the oil suction port (10) in the area where the outer rotor (3) is meshed with the inner rotor (4), and four independent high-pressure oil cavities (11) are formed at the oil pressing port (9) in the area where the outer rotor (3) is meshed with the inner rotor (4).