CN112855528A

CN112855528A - Gear pump

Info

Publication number: CN112855528A
Application number: CN202110071821.4A
Authority: CN
Inventors: 不公告发明人
Original assignee: Ningbo Wenze Electromechanical Technology Development Co ltd
Current assignee: Ningbo Wenze Electromechanical Technology Development Co ltd
Priority date: 2021-01-19
Filing date: 2021-01-19
Publication date: 2021-05-28

Abstract

The invention belongs to the technical field of pump equipment. In order to realize the variable discharge capacity of the gear pump, the invention discloses a gear pump which comprises a pump body, a driving gear, a driven gear, a variable shaft and a variable rod, wherein the pump body is provided with a driving gear and a driven gear; an oil inlet and an oil outlet are formed in the pump body; the driving gear and the driven gear are positioned in the pump body and are in meshed connection, and an oil suction cavity and an oil discharge cavity are formed between the meshed positions of the driving gear and the driven gear and the pump body; the variable shaft is rotationally connected with the pump body and is provided with an overflowing hole penetrating along the radial direction of the variable shaft; the oil suction cavity is communicated with the oil inlet, the oil discharge cavity is communicated with the oil outlet, a direct-current channel is arranged between the oil suction cavity and the oil discharge cavity, and the variable shaft is positioned on the direct-current channel to control the on-off of the direct-current channel; the variable rod is connected with the variable shaft to drive the variable shaft to rotate in a reciprocating mode relative to the pump body. The gear pump can realize real-time adjustment of the discharge capacity, thereby meeting the use of more working conditions and having higher use efficiency.

Description

Gear pump

Technical Field

The invention belongs to the technical field of pumps, and particularly relates to a gear pump.

Background

In the hydraulic field, a gear pump has: the gear pump has the advantages of simple structure, small volume, light weight, few parts, good manufacturability, easy manufacture, convenient maintenance, low price, good self-absorption performance, insensitivity to the pollution of oil liquid, difficult seizure or blockage in work engineering, capability of conveying high-viscosity oil liquid, high-consistency fluid and the like, and is widely applied to the hydraulic field.

However, the conventional gear pump has the following disadvantages in use: the gear pump has the advantages of large flow and pressure pulsation, large noise, low high-temperature efficiency, invariable discharge capacity and the like, wherein the invariable discharge capacity limits the application range of the gear pump to a great extent.

Disclosure of Invention

In order to realize variable displacement of the gear pump, the invention provides a gear pump. The gear pump comprises a pump body, a driving gear, a driven gear, a variable shaft and a variable rod; an oil inlet and an oil outlet are formed in the pump body; the driving gear and the driven gear are positioned in the pump body and are in meshed connection, and an oil suction cavity and an oil discharge cavity are formed between the meshed positions of the driving gear and the driven gear and the pump body; the variable shaft is rotatably connected with the pump body, and is provided with an overflowing hole penetrating along the radial direction of the variable shaft; the oil suction cavity is communicated with the oil inlet, the oil discharge cavity is communicated with the oil outlet, a direct-current channel is arranged between the oil suction cavity and the oil discharge cavity, and the variable shaft is positioned on the direct-current channel to control the on-off of the direct-current channel; the variable rod is connected with the variable shaft to drive the variable shaft to rotate in a reciprocating mode relative to the pump body.

Preferably, the gear pump is provided with a plurality of the driven gears and a plurality of variable shafts; the driven gears are sequentially in meshing transmission connection with the driving gear along the circumferential direction of the driving gear, and form a plurality of oil suction cavities and a plurality of oil discharge cavities; a direct current channel is arranged between the oil suction cavity and the oil discharge cavity corresponding to each driven gear, and a plurality of variable shafts are distributed on the direct current channels to control the on-off of the corresponding direct current channels.

Further preferably, the variable rod is connected with a plurality of variable shafts simultaneously to drive a plurality of direct current channels are arranged on the pump body and keep a parallel position relationship, and after all the variable shafts are connected with the variable rod, included angles of 0-180 degrees exist between overflowing holes in any two variable shafts.

Further preferably, all the direct current channels are arranged on the pump body, included angles of 0-180 degrees exist between any two direct current channels, and after all the variable shafts are connected with the variable rod, overflowing holes on all the variable shafts keep a parallel position relation.

Preferably, the variable rod is movably connected with the pump body, and the variable rod is movably connected with the variable shaft to drive the variable shaft to rotate reciprocally relative to the pump body.

Further preferably, the variable rod is connected with the pump body in a sliding manner along a linear direction; one end of the variable shaft is provided with a connecting plate along the radial direction of the variable shaft, the connecting plate is provided with a sliding groove, and the variable rod is provided with a connecting pin; one end of the connecting pin is positioned in the sliding groove and can slide back and forth along the sliding groove.

Further preferably, the gear pump is also provided with a variable electric pole; the output end of the variable electric pole is connected with the variable shaft to drive the variable shaft to perform reciprocating linear movement relative to the pump body.

Preferably, a return-to-zero direct current channel is also arranged between the oil inlet and the oil outlet, a return-to-zero variable shaft capable of rotating in a reciprocating manner relative to the pump body is arranged on the return-to-zero direct current channel, and a return-to-zero overflowing hole is arranged on the return-to-zero variable shaft so as to control the on-off of the return-to-zero direct current channel.

Preferably, the variable shaft and the pump body are detachably and fixedly connected.

Compared with the conventional gear pump, the gear pump has the following beneficial technical effects:

1. in the gear pump, the variable shaft which is driven by the variable rod to rotate relative to the pump body is arranged, and the on-off relation between the oil discharge cavity and the oil suction cavity is controlled by the variable shaft, so that in the process of outputting high-pressure media in normal work of the gear pump, the flow area between the oil discharge cavity and the oil suction cavity can be adjusted by controlling the rotation of the variable shaft by the variable rod, the displacement is adjusted, and the variable control effect of the gear pump is achieved.

2. In the gear pump, a plurality of driven gears are in meshing transmission connection with a driving gear, and a plurality of variable shafts are arranged to respectively control the communication relation between an oil discharge cavity and an oil suction cavity in the driven gears. Like this, just can adjust control the intercommunication relation of oil extraction chamber and oil absorption chamber among the different driven gear through the turned angle of controlling a plurality of variable axles relative to the pump body to carry out many grades to the discharge capacity of gear pump and divide, and realize the many grades of control effect to the different discharge capacities of gear pump, improve the accurate variable control to the gear pump.

3. In the gear pump of the present invention, the variable shaft and the driven gear are coaxially provided, and the variable shaft serves as a rotation shaft for rotating the driven gear at the same time. Therefore, the rotating shaft of the driven gear can be omitted, the variable shaft is used as the rotating shaft of the driven gear in the process of displacement adjustment, the utilization rate of the variable shaft is improved, and the structural design of the whole gear pump is optimized.

Drawings

FIG. 1 is a schematic cross-sectional view of a gear pump according to the present embodiment in a maximum displacement condition;

FIG. 2 is a schematic sectional view of a gear pump of the present embodiment taken along the direction M-M in FIG. 1;

FIG. 3 is a schematic sectional view of a gear pump of the present embodiment taken along the direction N-N in FIG. 1;

FIG. 4 is a schematic structural view of a gear pump of the present embodiment along direction F in FIG. 1;

FIG. 5 is a schematic cross-sectional view of the gear pump of the present embodiment at a second driven gear displacement taken in the direction N-N of FIG. 1;

FIG. 6 is a schematic structural view of the gear pump of the present embodiment at a second driven gear displacement taken in the direction F of FIG. 1;

FIG. 7 is a schematic cross-sectional view of the gear pump of the present embodiment at a first driven gear displacement taken in the direction N-N of FIG. 1;

FIG. 8 is a schematic structural view of the gear pump of the present embodiment at the first driven gear displacement, taken along the direction F in FIG. 1;

FIG. 9 is a schematic cross-sectional view of the gear pump of the present embodiment at zero displacement taken along the direction N-N in FIG. 1;

fig. 10 is a schematic structural diagram of the gear pump of the embodiment along the direction F in fig. 1 at zero displacement.

Detailed Description

The technical solution of the present invention will be further described in detail with reference to the accompanying drawings and embodiments.

As described with reference to fig. 1 to 4, the gear pump of the present embodiment includes a pump body 1, a driving gear 2, two identical driven gears, a first driven gear 31, a second driven gear 32, two variable shafts, a first variable shaft 41, a second variable shaft 42, and a variable lever 5.

An oil inlet 11 connected with an external low-pressure pipeline and an oil outlet 12 connected with an external high-pressure pipeline are arranged on the pump body 1. The driving gear 2 and the two driven gears are located in the same plane inside the pump body 1, and the two driven gears are simultaneously in meshed transmission connection with the driving gear 2. At this time, a first oil suction chamber 31a and a first oil discharge chamber 31b are respectively formed with the pump body 1 at both sides where the first driven gear 31 and the driving gear 2 form an engagement position, a second oil suction chamber 32a and a second oil discharge chamber 32b are respectively formed with the pump body 1 at both sides where the second driven gear 32 and the driving gear 2 form an engagement position, wherein the first oil suction chamber 31a and the second oil suction chamber 32a are simultaneously kept communicated with the oil inlet 11, the first oil discharge chamber 31b and the second oil discharge chamber 32b are simultaneously kept communicated with the oil outlet 12, a first straight flow passage 31c is provided between the first oil discharge chamber 31b and the first oil suction chamber 31a, and a second straight flow passage 32c is provided between the second oil discharge chamber 32b and the second oil suction chamber 32 a.

The first variable shaft 41 is provided with a first overflowing hole 411 penetrating along the radial direction thereof, and the first variable shaft 41 is positioned on the first straight flow channel 31c to control the communication relationship between the first overflowing hole 411 and the first straight flow channel 31 c. The second variable shaft 42 is provided with a second overflowing hole 421 penetrating along the radial direction thereof, and the second variable shaft 42 is positioned on the second straight flow channel 32c to control the communication relationship between the second overflowing hole 421 and the second flow channel 32 c. The first driven gear 31 is rotatably connected to the first variable shaft 41, and the second driven gear 32 is rotatably connected to the second variable shaft 42.

The variable rod 5 is directly movably connected with the pump body 1 and is simultaneously connected with the first variable shaft 41 and the second variable shaft 42 to drive the first variable shaft 41 and the second variable shaft 42 to rotate reciprocally relative to the pump body 1, so as to control the communication relationship between the first overflowing hole 411 and the first straight flow channel 31c and the communication relationship between the second overflowing hole 421 and the second flow channel 32c respectively.

At the moment, the driving gear is driven to rotate, the two driven gears can be driven to synchronously rotate, so that low-pressure media in the two oil suction cavities are compressed and boosted under the rotating action of the corresponding driving gear and the corresponding driven gears and are brought into corresponding oil discharge cavities, and then the low-pressure media flow to the oil outlet through the auxiliary oil way communicated with the corresponding oil discharge cavities, and the output of the high-pressure media is realized. Meanwhile, the variable rod drives the first variable shaft and the second variable shaft to rotate relative to the pump body, so that the communication relation between the first overflowing hole and the first straight-flow channel and the communication relation between the second overflowing hole and the second flow channel can be changed.

When the first variable shaft rotates to the first overflowing hole and is not communicated with the first direct-current channel, and the second variable shaft rotates to the second overflowing hole and is not communicated with the second direct-current channel, all high-pressure media in the first oil discharge cavity and the second oil discharge cavity converge to the oil outlet to be output, so that the gear pump is kept in a maximum displacement operation state; when the first variable shaft rotates to the first overflowing hole to be communicated with the first direct current channel, the first oil suction cavity is communicated with the first oil discharge cavity, so that the first driven gear forms idle rotation and loses output of high-pressure media; similarly, when the second variable shaft rotates to the second overflowing hole to be communicated with the second direct-current channel, the second oil suction cavity is communicated with the second oil discharge cavity, so that the second driven gear also idles to lose the output of high-pressure media, and the displacement of the gear pump is adjusted.

Referring to fig. 3, in the present embodiment, the first straight flow channel 31c and the second straight flow channel 32c are disposed on the pump body 1 in a parallel relationship, and the first overflowing hole 411 and the second overflowing hole 421 are disposed at an included angle, that is, the first overflowing hole 411 and the second overflowing hole 421 are connected to the variable rod 5 at initial positions at different included angles of 0 to 180 degrees with respect to the first straight flow channel 31c and the second straight flow channel 32c, respectively.

At the moment, in the process of gradually driving the first variable shaft and the second variable shaft to rotate through the variable rod, the first overflowing hole and the second overflowing hole are sequentially and respectively communicated with the first direct-current channel and the second direct-current channel, namely only the first driven gear enters an idling state or the second driven gear performs an idling state at a single time, so that the gear pump can be adjusted step by step among multiple displacement volumes.

Similarly, in other embodiments, the first overflowing hole and the second overflowing hole can be installed and connected with the variable rod in a parallel position, and the first straight-flow channel and the second straight-flow channel are arranged at an included angle, that is, the first straight-flow channel and the second straight-flow channel are arranged at an included angle and form a position relationship of 0-180 degrees with the first overflowing hole and the second overflowing hole.

Further, as shown in fig. 1, 3 and 4, a return-to-zero variable shaft 43 is further provided on the gear pump of the present embodiment, and a return-to-zero direct-flow passage 13 is provided between the oil inlet 11 and the oil outlet 12. The return-to-zero variable shaft 43 is rotatably connected with the pump body 1 and connected with the variable rod 5, and the return-to-zero variable shaft 43 is located on the return-to-zero direct-current channel 13 and provided with a return-to-zero overflowing hole 431 along the radial direction of the return-to-zero variable shaft to control the on-off of the return-to-zero direct-current channel 13, namely, the on-off of the oil inlet 11 and the oil outlet 12.

At the moment, in the process that the variable rod drives the first variable shaft, the second variable shaft and the return-to-zero variable shaft to rotate relative to the pump body, when the variable rod rotates to the state that the first overflowing hole is communicated with the first direct-current channel or the second overflowing hole is communicated with the second direct-current channel, the corresponding first driven gear or second driven gear enters an idle state to achieve the adjustment effect of reducing the displacement, and when the variable rod rotates to the state that the return-to-zero overflowing hole is communicated with the return-to-zero direct-current channel, the oil inlet is directly communicated with the oil outlet, so that the whole gear pump directly performs a zero displacement state to achieve the quick return-to-zero control effect of the displacement of the gear pump.

In this embodiment, through two driven gears of outer circumferencial direction equipartition at the driving gear, form two oil extraction chambeies and carry out high-pressure medium output simultaneously, set up two corresponding direct current passageways and one and return to zero direct current passageway and relevant three variable axle simultaneously to the realization can be at the regulation control between full displacement, first driven gear displacement, second driven gear displacement and zero displacement to this gear pump. Similarly, in other embodiments, according to the requirements of use conditions and design, the size and the number of the driven gears, even the space size of the oil suction cavity and the oil discharge cavity can be completely adjusted according to the maximum displacement requirement, so that the maximum displacement requirement of the gear pump is met, the number of variable shafts and direct-current channels is increased, the gear pump can be adjusted among more different displacements, and a higher fine adjustment effect is obtained.

As shown in fig. 3, in the present embodiment, one variable rod 6 is provided at the end of the variable rod 5, and is driven by the variable rod 6 to perform reciprocating linear movement with respect to the pump body 1. Meanwhile, a connecting plate 44 is provided at each end of the three variable shafts in the radial direction, and a slide groove 441 is provided at each connecting plate 44, and three connecting pins 51 are provided at the variable rod 5. The free ends of the three connecting pins 51 are respectively located in the three sliding grooves 441, and can slide along the respective sliding grooves 441 in a reciprocating manner.

At the moment, the variable rod can drive the three connecting pins to move along the three sliding grooves respectively to move relatively under the driving action of the variable rod relative to the pump body, so that the three variable shafts are driven to rotate through the connecting plates, the on-off relation between the overflowing holes in the three variable shafts and the corresponding direct-current channels is changed, and the displacement of the gear pump is adjusted.

Similarly, in other embodiments, other devices may be used to drive the variable electric pole to reciprocate, such as an air cylinder or a linear motor, and at the same time, three independent variable electric poles may be used to control the rotation of the three variable shafts respectively, or even three motors are directly connected to the three variable shafts, so that the rotation of the variable shafts is controlled by controlling the rotation angle of the motors.

In addition, in other embodiments, the variable rod may be designed to have a rack structure, and the outer circumferential surface of the variable shaft is provided with straight teeth, so that the variable rod and the variable shaft form a transmission connection of tooth engagement, thereby achieving driving control of rotation of the variable shaft.

Referring to fig. 1, in the present embodiment, the

variable shafts

41 and 42 are detachably and rotatably connected to the pump body 1, that is, the

variable shafts

41 and 42 are axially fixed by the detachable pump cover 14 after being rotatably connected to the pump body 1. Like this, in the use of this gear pump, according to the change that uses operating mode and operation requirement, set up the variable axis that angle and aperture size are different to the overflowing hole and carry out quick replacement to satisfy the operation requirement of more operating modes, improve the availability factor of whole gear pump.

Further, in the present embodiment, the

variable shafts

41, 42 are provided coaxially with the first driven gear 31 and the second driven gear 32, respectively, so that the

variable shafts

41, 42 can serve as the rotating shafts of the first driven gear 31 and the second driven gear 32, respectively. Therefore, the independent arrangement of the rotating shafts of the first driven gear and the second driven gear can be omitted, the service efficiency of the variable shaft is improved, and the structural design of the whole gear pump is optimized.

In this embodiment, the driving gear adopts the structural style of gear shaft, directly is equipped with the drive shaft on the driving gear and carries out the connection of external drive equipment. Similarly, in other embodiments, the external driving device may be connected to the driving gear by an independent driving shaft, and the driving shaft may be connected to the driving gear by a detachable fixed connection. Like this, just can use operating mode quick replacement to have the drive shaft of different structural style according to the difference, for example integral key shaft or flat key shaft to satisfy and be connected with the external drive arrangement of different structural styles, guarantee the normal use of this gear pump.

In addition, in this embodiment, since the first oil discharge chamber and the second oil discharge chamber are in communication with the same oil outlet, a check valve is respectively disposed on the oil path between the first oil discharge chamber and the oil outlet and the oil path between the second oil discharge chamber and the oil outlet, so that the high-pressure medium in the first oil discharge chamber flows to the oil outlet in a one-way manner and the high-pressure medium in the second oil discharge chamber flows to the oil outlet in a one-way manner, thereby preventing the first oil discharge chamber and the second oil discharge chamber from forming a direct communication relationship, and ensuring smooth adjustment of the displacement of the gear pump.

Referring to fig. 1 to 10, when the gear pump of this embodiment outputs a high-pressure medium, first, an external low-pressure pipeline is connected to the oil inlet 11, and the external high-pressure pipeline is connected to the oil outlet 12, and then, an external driving device is started to drive the driving gear 2 to rotate, so as to drive the first driven gear 31 and the second driven gear 32 to synchronously rotate, so that the first oil suction cavity 31a and the second oil suction cavity 32a form a negative pressure to introduce the low-pressure medium at the oil inlet 11, and further, the low-pressure medium is compressed and does work under the rotation action of the driving gear 2, the first driven gear 31 and the second driven gear 32, and is brought into the corresponding first oil discharge cavity 31b and the second oil discharge cavity 32b, and then flows together to the oil outlet 12, thereby outputting the high-pressure medium.

During the operation of the gear pump, the variable electric pole 6 is started when the displacement is to be adjusted, and the variable rod 5 drives the first variable shaft 41, the second variable shaft 42 and the return-to-zero variable shaft 43 to gradually rotate relative to the pump body 1, so that the on-off relationship among the first direct current channel 31c, the second direct current channel 32c and the return-to-zero direct current channel 13 is changed, that is, the communication relationship between the first oil suction cavity 31a and the first oil discharge cavity 31b, the communication relationship between the second oil suction cavity 32a and the second oil discharge cavity 32b, and the communication relationship between the oil inlet 11 and the oil outlet 12 are adjusted, and the adjustment of the displacement of the gear pump is further achieved.

When the variable lever 5 is in the position shown in fig. 4 and the first variable shaft 41, the second variable shaft 42, and the return-to-zero variable shaft 43 are in the position shown in fig. 3, the first dc path 31c, the second dc path 32c, and the return-to-zero dc path 13 are all in the off state. At this time, the first oil suction chamber 31a and the first oil discharge chamber 31b on both sides of the first driven gear 31 are in a disconnected state, the high-pressure medium flowing into the first oil discharge chamber 31b through the first driven gear 31 and the driving gear 2 all flows to the oil outlet 12, the second oil suction chamber 32a and the second oil discharge chamber 32b on both sides of the second driven gear 32 are also in a disconnected state, and the high-pressure medium flowing into the second oil discharge chamber 32b through the second driven gear 32 and the driving gear 2 all flows to the oil outlet 12, so that the gear pump is maintained to operate under the maximum displacement condition of the sum of the displacement of the first driven gear, the displacement of the second driven gear and the displacement of the driving gear.

When the variable lever 5 is moved to the position shown in fig. 6 and the first variable shaft 41, the second variable shaft 42 and the return-to-zero variable shaft 43 are rotated to the position shown in fig. 5, the first through-flow hole 411 communicates the first dc path 31c, and the second dc path 32c and the return-to-zero dc path 13 are in the disconnected state. At this time, the oil inlet 11 and the oil outlet 12 are in a disconnected state, the first oil suction chamber 31a and the first oil discharge chamber 31b on both sides of the first driven gear 31 are in a communicating relationship, and the second oil suction chamber 32a and the second oil discharge chamber 32b on both sides of the second driven gear 32 are in a disconnected state. In this way, the high-pressure medium in the first oil suction chamber 31a flowing to the first oil discharge chamber 31b through the first driven wheel 31 and in the second oil suction chamber 32a flowing to the first oil discharge chamber 31b through the driving gear 2 all flows back to the oil inlet 11, while the high-pressure medium in the first oil suction chamber 31a flowing to the second oil discharge chamber 32b through the driving gear 2 and in the second oil suction chamber 32a flowing to the second oil discharge chamber 32b through the second driven gear 32 all flows to the oil outlet 12, so that the gear pump is kept to operate under the condition of the sum of the full displacement of the second driven wheel and the half displacement of the driving gear.

When the variable lever 5 is moved to the position shown in fig. 8 and the first variable shaft 41, the second variable shaft 42 and the return-to-zero variable shaft 43 are rotated to the position shown in fig. 7, the second flow passing hole 421 connects the second direct current passage 32c, and the first direct current passage 31c and the return-to-zero direct current passage 13 are disconnected. At this time, the oil inlet 11 and the oil outlet 12 are in a disconnected state, the first oil suction chamber 31a and the first oil discharge chamber 31b on both sides of the first driven gear 31 are in a disconnected state, and the second oil suction chamber 32a and the second oil discharge chamber 32b on both sides of the second driven gear 32 are in a communicating relationship. In this way, the high-pressure medium in the first oil suction chamber 31a flowing to the first oil discharge chamber 31b through the first driven wheel 31 and in the second oil suction chamber 32a flowing to the first oil discharge chamber 31b through the driving gear 2 all flows back to the oil outlet 12, and the high-pressure medium in the first oil suction chamber 31a flowing to the second oil discharge chamber 32b through the driving gear 2 and in the second oil suction chamber 32a flowing to the second oil discharge chamber 32b through the second driven gear 32 all flows back to the oil inlet 11, so that the gear pump is kept to operate under the condition of the sum of the full displacement of the first driven wheel and the half displacement of the driving gear.

When the variable lever 5 is moved to the position shown in fig. 10 and the first variable shaft 41, the second variable shaft 42 and the return-to-zero variable shaft 43 are rotated to the position shown in fig. 9, the first dc path 31c and the second dc path 32c are in the disconnected state, and the return-to-zero orifice 431 communicates the return-to-zero dc path 13. At this time, the oil inlet 11 and the oil outlet 12 are directly communicated, the first oil suction chamber 31a and the first oil discharge chamber 31b on both sides of the first driven gear 31 are communicated, the second oil suction chamber 32a and the second oil discharge chamber 32b on both sides of the second driven gear 32 are also communicated, so that all high-pressure media flowing into the first oil discharge chamber 31b and the second oil discharge chamber 32b flow to the oil inlet 11, the gear pump is operated under a zero-displacement working condition, and the output of the high-pressure media is stopped.

In the adjusting process, the through flow area of the direct flow channel can be accurately and finely adjusted by accurately controlling the rotation angle of the variable shaft, so that the fine adjustment effect on the discharge capacity of the gear pump is achieved.

Claims

1. A gear pump is characterized by comprising a pump body, a driving gear, a driven gear, a variable shaft and a variable rod; an oil inlet and an oil outlet are formed in the pump body; the driving gear and the driven gear are positioned in the pump body and are in meshed connection, and an oil suction cavity and an oil discharge cavity are formed between the meshed positions of the driving gear and the driven gear and the pump body; the variable shaft is rotatably connected with the pump body, and is provided with an overflowing hole penetrating along the radial direction of the variable shaft; the oil suction cavity is communicated with the oil inlet, the oil discharge cavity is communicated with the oil outlet, a direct-current channel is arranged between the oil suction cavity and the oil discharge cavity, and the variable shaft is positioned on the direct-current channel to control the on-off of the direct-current channel; the variable rod is connected with the variable shaft to drive the variable shaft to rotate in a reciprocating mode relative to the pump body.

2. Gear pump according to claim 1, characterized in that it is provided with a plurality of said driven gears and a plurality of variable shafts; the driven gears are sequentially in meshing transmission connection with the driving gear along the circumferential direction of the driving gear, and form a plurality of oil suction cavities and a plurality of oil discharge cavities; a direct current channel is arranged between the oil suction cavity and the oil discharge cavity corresponding to each driven gear, and a plurality of variable shafts are distributed on the direct current channels to control the on-off of the corresponding direct current channels.

3. The gear pump of claim 2, wherein the variable rod is connected to a plurality of the variable shafts simultaneously to drive the plurality of variable shafts simultaneously in rotation relative to the pump body.

4. The gear pump of claim 3, wherein all the direct flow channels are formed in the pump body and are maintained in a parallel position, and after all the variable shafts are connected with the variable rod, an included angle of 0-180 degrees is formed between overflowing holes in any two variable shafts.

5. The gear pump of claim 3, wherein all the direct flow channels are formed in the pump body, an included angle of 0-180 degrees exists between any two direct flow channels, and after all the variable shafts are connected with the variable rod, the overflowing holes in all the variable shafts are kept in a parallel position relation.

6. The gear pump of any one of claims 1-5, wherein the variable rod is movably coupled to the pump body and the variable rod is movably coupled to the variable shaft to drive the variable shaft in reciprocating rotation relative to the pump body.

7. The gear pump of claim 6, wherein the variable rod is slidably connected to the pump body in a linear direction; one end of the variable shaft is provided with a connecting plate along the radial direction of the variable shaft, the connecting plate is provided with a sliding groove, and the variable rod is provided with a connecting pin; one end of the connecting pin is positioned in the sliding groove and can slide back and forth along the sliding groove.

8. Gear pump according to claim 7, characterized in that it is further provided with a variable electric pole; the output end of the variable electric pole is connected with the variable shaft to drive the variable shaft to perform reciprocating linear movement relative to the pump body.

9. The gear pump of any one of claims 1-5, wherein a return-to-zero direct-current channel is also disposed between the oil inlet and the oil outlet, and a return-to-zero variable shaft capable of reciprocating rotation relative to the pump body is disposed on the return-to-zero direct-current channel, and a return-to-zero overflow hole is disposed on the return-to-zero variable shaft to control on/off of the return-to-zero direct-current channel.

10. Gear pump according to any of claims 1 to 5, characterized in that the variable shaft is detachably and fixedly connected with the pump body.