CN113586440B

CN113586440B - Gear pump

Info

Publication number: CN113586440B
Application number: CN202111061844.3A
Authority: CN
Inventors: 亓桂景; 林君雄; 赵烨
Original assignee: Ningbo Hong Motor Co ltd
Current assignee: Ningbo Hong Motor Co ltd
Priority date: 2021-09-10
Filing date: 2021-09-10
Publication date: 2022-12-20
Anticipated expiration: 2041-09-10
Also published as: CN113586440A

Abstract

The invention discloses a gear pump, which comprises a pump body, a pump shaft, a driving gear, a driven gear and a side plate, wherein the pump shaft is arranged on the pump body; the pump body is provided with an inlet and an outlet; the driving gear and the driven gear are positioned in the pump body in a tooth meshing manner, and a liquid inlet cavity communicated with the inlet and a liquid outlet cavity communicated with the outlet are formed; the pump shaft is coaxially connected with the driving gear so as to drive the driving gear to rotate; the side plates are positioned in the pump body, are respectively positioned between the axial end surface of the driving gear and the inner wall of the pump body, and are also positioned between the axial end surface of the driven gear and the inner wall of the pump body; the side plate can reciprocate relative to the driving gear and the driven gear along the axial direction of the driving gear. The gear pump can rotate in a no-load way in the early stage of starting, reduces impact, enables fluid to uniformly cover the axial end faces of the driving gear and the driven gear, reduces subsequent friction and prolongs the service life.

Description

Gear pump

Technical Field

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

Background

The gear pump is a rotary pump which is formed by two meshed gears which are tightly matched and mutually meshed and rotated in a shell to form working volume change so as to convey liquid or pressurize the liquid. When the gear rotates, the space volume of the gear disengagement side is changed from small to large, vacuum is formed, liquid is sucked, and the space volume of the gear engagement side is changed from large to small, so that the liquid is squeezed into the pipe.

The existing gear pump is started at high pressure when starting to work due to the structural characteristics of the gear pump, and the starting mode can cause great impact on the gear pump and a hydraulic circuit; and when the gear pump starts to work, because no uniform oil layer exists between the side face and the side wall of the gear, large friction is generated between the side face and the side wall of the gear, and the service life of the gear pump can be shortened.

Disclosure of Invention

Aiming at the problems of the existing gear pump, the invention provides a gear pump with a brand new structure.

The gear pump comprises a pump body, a pump shaft, a driving gear, a driven gear and a side plate; the pump body is provided with an inlet and an outlet; the driving gear and the driven gear are positioned in the pump body in a tooth meshing manner, and form a liquid inlet cavity communicated with the inlet and a liquid outlet cavity communicated with the outlet; the pump shaft is coaxially connected with the driving gear so as to drive the driving gear to rotate; the side plates are positioned in the pump body and positioned between the axial end surface of the driving gear and the inner wall of the pump body and between the axial end surface of the driven gear and the inner wall of the pump body; the side plate is capable of reciprocating relative to the drive gear and the driven gear in an axial direction of the drive gear.

Preferably, the gear pump is also provided with an elastic piece; a control cavity is formed between the side plate and the inner wall of the pump body and is used for containing high-pressure fluid to drive the side plate to move towards the direction close to the driving gear and the driven gear; the elastic piece is located between the side plate and the driving gear and/or the driven gear so as to drive the side plate to move towards a direction far away from the driving gear and the driven gear.

Preferably, the gear pump is provided with a high-pressure flow passage and a low-pressure flow passage; one end of the high-pressure flow passage is communicated with high-pressure fluid, and the other end of the high-pressure flow passage is communicated with the control cavity; one end of the low-pressure flow passage is communicated with the control cavity, and the other end of the low-pressure flow passage is selectively communicated with low-pressure fluid.

Preferably, the gear pump is provided with a rotary table, a sliding block and a sliding block elastic piece; the rotary disc is coaxially and fixedly connected with the driving gear or the driven gear, a connecting flow channel is arranged on the rotary disc, and the low-pressure flow channel penetrates through the connecting flow channel; the sliding block is eccentrically arranged on the rotary table and can slide in a reciprocating manner relative to the rotary table along the diameter direction of the rotary table; the sliding block elastic piece is positioned between the sliding block and the rotating disc so as to drive the sliding block to move to a position for cutting off the connecting flow channel relative to the rotating disc.

Preferably, the gear pump is provided with a liquid supply flow passage and a high-pressure piston; the high-pressure piston is connected with the driving gear or the driven gear to perform reciprocating movement; the liquid supply channel is communicated with low-pressure fluid, the output end of the high-pressure piston is respectively and selectively communicated with the liquid supply channel and the high-pressure channel, and the low-pressure fluid is introduced from the liquid supply channel and is output to the high-pressure channel.

Preferably, the gear pump is provided with a cam and a piston elastic member; the cam is coaxially and fixedly connected with the driving gear or the driven gear, and the high-pressure piston is in sliding connection with the pump body along the radial direction of the driving gear and is in sliding contact with the cam; the piston elastic piece is positioned between the high-pressure piston and the pump body so as to drive the high-pressure piston to be kept in a sliding connection state with the cam.

Preferably, the gear pump is provided with a first check valve and a second check valve; the first check valve is positioned in the liquid supply flow channel to control the low-pressure fluid to flow to the high-pressure piston in a one-way mode; the second check valve is positioned in the high-pressure flow passage to control high-pressure fluid to flow out of the high-pressure piston.

Preferably, the gear pump is provided with an overflow valve; the overflow valve is positioned between the control cavity and the low-pressure fluid and is used for controlling the highest pressure of the high-pressure fluid in the control cavity.

Preferably, the gear pump is provided with a positioning piece, and the side plate is provided with a positioning groove; the positioning piece is connected with the pump body in a sliding mode, can move relative to the pump body to be connected with the positioning groove, and fixes the side plate at a position close to the driving gear and the driven gear.

Preferably, the positioning member comprises a positioning piston and a positioning elastic member; the positioning elastic piece is positioned between the pump body and one end of the positioning piston so as to drive the positioning piston to move to a position where the positioning piston is separated from being connected with the positioning groove; the other end of the positioning piston is communicated with a control fluid to drive the positioning piston to overcome the positioning elastic piece to move to a position connected with the positioning groove.

The gear pump has the following beneficial technical effects:

1. in the invention, the side plates capable of moving back and forth are arranged at the axial end parts of the driving gear and the driven gear, so that the distance between the end surfaces of the driving gear and the driven gear and the side plates is adjusted, the gear pump rotates in no-load mode in the early stage of starting, the impact is reduced, the fluid uniformly covers the axial end surfaces of the driving gear and the driven gear, the subsequent friction is reduced, and the service life is prolonged.

2. In the invention, when the gear pump is started, the high-pressure piston reciprocates along with the rotation of the cam, so that high-pressure fluid is injected into the control cavity to push the side plate to lean against the driving gear and the driven gear, the gear pump starts to normally work after the side plate is lean against the driving gear and the driven gear, the side plate is started in an idle state in the earlier stage, and the high-pressure fluid pushes the positioning piece to position the side plate, so that the leakage caused by the increase of a gap between the side plate and the driving gear and the driven gear in the normal working process of the gear pump is avoided.

3. In the invention, by arranging the turntable and the slide block, the turntable synchronously rotates in the starting process of the gear pump, centrifugal force drives the slide block to overcome the movement of the slide block elastic part, and the slide block moves to the cut-off connecting flow passage, so that high-pressure fluid in the control cavity flows out through the overflow valve, and the fluid in the control cavity keeps a pressure stable state, thereby ensuring that the positioning part positions the side plate and ensuring the stable work of the gear pump.

4. In the invention, by using the turntable and the built-in slide block, when the gear pump stops, the slide block is pushed under the action of the slide block elastic part to open the connecting flow passage, so that high-pressure fluid in the control cavity is discharged, and the positioning part releases the positioning of the side plate, so that the side plate is far away from the driving gear and the driven gear.

Drawings

FIG. 1 is a schematic sectional view of a gear pump according to the present embodiment;

FIG. 2 isbase:Sub>A schematic cross-sectional view taken along the line A-A in FIG. 1;

FIG. 3 is a schematic cross-sectional view taken along the line B-B in FIG. 1;

FIG. 4 is an enlarged view of a portion of the structure at I in FIG. 1;

FIG. 5 is an enlarged view of a portion of FIG. 1 at II;

FIG. 6 is a schematic sectional view illustrating the gear pump according to the present embodiment in normal operation;

fig. 7 is a schematic cross-sectional view along the direction B-B in fig. 6.

Detailed Description

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

As shown in fig. 1 to 7, the gear pump of the present embodiment includes a pump body 1, a pump shaft 2, a drive gear 31, a driven gear 32, a first side plate 41, and a second side plate 42. An inlet 11 and an outlet 12 are provided in the pump body 1. The driving gear 31 and the driven gear 32 are located inside the pump body 1 in a toothed engagement, and form an inlet chamber 13 communicating with the inlet 11 and an outlet chamber 14 communicating with the outlet 12. One end of the pump shaft 2 extends into the pump body 1 and is coaxially and fixedly connected with the driving gear 31 to drive the driving gear 31 to rotate. The first side plate 41 and the second side plate 42 are both located inside the pump body 1, the first side plate 41 is located between one axial end face of the driving gear 31 and the inner wall of the pump body 1, the second side plate 42 is located between the other axial end face of the driving gear 31 and the inner wall of the pump body 1, and the first side plate can reciprocate relative to the driving gear 31 in the axial direction of the driving gear 31.

In the embodiment, the driving gear and the driven gear are located in the same plane, and the first side plate and the second side plate are located between the driven gear and the inner wall of the pump body at the same time, so that the driving gear and the driven gear can perform reciprocating movement relative to the driven gear along the axial direction of the driven gear. Of course, in other embodiments, according to the external shape structure or other design requirements of the pump body, the driving gear and the driven gear are located in different planes, and then the first side plate and the second side plate can be bent according to the situation, so that the effect of performing relative reciprocating synchronous movement relative to the driving gear and the driven gear is met.

At this time, in the operation process of the gear pump, the size of the clearance between the side plate and the axial end face of the driving gear and the axial end face of the driven gear can be changed by controlling the reciprocating movement of the first side plate and the second side plate in the pump body. In the initial stage of starting the gear pump, the size of the gap between the driving gear and the driven gear along the axial direction can be increased by controlling the movement of the first side plate and the second side plate, so that more fluid media flow to the axial end face of the driving gear and the axial end face of the driven gear under the condition of no-load rotation of the gear pump, and lubrication is formed between the driving gear and the pump body and between the driven gear and the pump body; when the gear pump enters a working stage, the size of the gap between the driving gear and the driven gear along the axial direction is reduced by controlling the first side plate and the second side plate to move, so that the gear pump enters a normal working state, and the output operation of a high-pressure medium is completed.

As shown in fig. 1 to 7, in the gear pump of the present embodiment, four elastic members 43 are further provided and are respectively located at both axial ends of the driving gear 31 and both axial ends of the driven gear 32, so that the first side plate 41 and the second side plate 42 are respectively driven to move in a direction away from the driving gear 31 and the driven gear 32. Meanwhile, an annular first control cavity 151 is formed between the first side plate 41 and the inner wall of the pump body 1, an annular second control cavity 152 is formed between the second side plate 42 and the inner wall of the pump body 1, and the first control cavity 151 and the second control cavity 152 are used for containing high-pressure fluid so as to respectively drive the first side plate 41 and the second side plate 42 to overcome the elastic piece 43 and move towards the direction close to the driving gear 31 and the driven gear 32.

Therefore, the first side plate and the second side plate can be driven to move relative to the pump body by controlling the pressure of high-pressure fluid entering the first control cavity and the second control cavity, and therefore the gap between the first side plate and the second side plate and between the driving gear and the driven gear can be adjusted.

Further, the pump body 1 of the present embodiment is provided with a high-pressure flow passage 161 and a low-pressure flow passage 162. One end of the high pressure flow passage 161 is connected to the high pressure fluid, and the other end thereof extends to be connected to the first control chamber 151 and the second control chamber 152. One end of the low pressure flow passage 162 communicates with the first control chamber 151 and the second control chamber 152, respectively, and the other end extends to selectively communicate with the low pressure fluid.

At the moment, the communication relation between the low-pressure flow channel and the low-pressure fluid is controlled, so that the fluid pressure in the first control cavity and the fluid pressure in the second control cavity can be controlled, and the first side plate and the second side plate can be controlled to move in a reciprocating mode relative to the pump body by matching with the elastic piece.

Wherein, in this embodiment, first curb plate and second curb plate adopt reciprocal bending structure form to directly form first control chamber and second control chamber by first curb plate and second curb plate, reduce the processing operation to the pump body, reduce the manufacturing degree of difficulty of this gear pump. Meanwhile, the low-pressure flow passage directly extends to be communicated with the inlet so as to realize the communication with the low-pressure fluid, and of course, in other embodiments, the low-pressure flow passage can be led out to the low-pressure fluid separately, such as an oil tank.

In addition, in this embodiment, low pressure runner and high pressure runner all set up on the pump body to reduce the setting of external pipeline, improve the integrated level of whole gear pump. Of course, in other embodiments, the design of the external pipeline may be adopted to perform the fluid diversion operation according to different design and use conditions.

As shown in fig. 1 to 7, a rotary disk 51, a slider 52, and a slider elastic member 53 are further provided in the gear pump of the present embodiment. Wherein, carousel 51 and driven gear 32 coaxial fixed connection, carousel 51 are equipped with connection runner 511, and low pressure runner 162 passes connection runner 511, and connection runner 511 belongs to the part of low pressure runner 162. The slider 52 is eccentrically disposed on the turntable 51 and is capable of reciprocating sliding with respect to the turntable 51 in a diameter direction of the turntable 51. The slider elastic member 53 is a coil spring and is located between the slider 52 and the turntable 51 to drive the slider 52 to move relative to the turntable 51 to a position where the connection flow passage 511 is shut off.

At the moment, the centrifugal force generated by the rotation of the rotating disc along with the driven gear is utilized to enable the sliding block to move relative to the rotating disc under the action of the centrifugal force, so that the sliding block overcomes the acting force of the elastic piece of the sliding block and moves to the cut-off connection flow passage, and the low-voltage flow passage is in a broken circuit state. On the contrary, when the driven gear stops rotating, the rotating disc also stops rotating, and the sliding block reversely moves to the position for communicating the connecting flow passage under the action of the sliding block elastic piece, so that the low-pressure flow passage is kept in a communicating state.

In this embodiment, the cooperation of carousel, slider and slider elastic component is utilized to realize following the automatic on-off control that the driven gear rotated the condition to the low pressure runner, realizes the automatic control effect. Of course, in other embodiments, the on/off of the low pressure flow passage may be controlled in other manners, for example, by using a control valve to control the operation of the control valve according to the rotation of the pump shaft, so as to control the on/off of the low pressure flow passage.

As shown in fig. 1 to 7, the gear pump of the present embodiment is further provided with a liquid supply passage 163 and a high-pressure piston 61. Wherein the high pressure piston 61 is connected to the driving gear 31 to reciprocate. The supply channel 163 is in communication with the low pressure fluid at the inlet 11 and the output of the high pressure piston 61 is in selective communication with the supply channel 163 and the high pressure channel 161, respectively.

At the moment, the high-pressure piston forms reciprocating movement relative to the pump body in the rotation process along with the driving gear, so that low-pressure fluid is guided to the output end of the high-pressure piston through the liquid supply channel, then the high-pressure piston does work on the low-pressure fluid and outputs the low-pressure fluid to the high-pressure channel, the purpose of outputting the high-pressure fluid to the high-pressure channel is achieved, and the high-pressure fluid flows into the first control cavity and the second control cavity to move and drive the first side plate and the second side plate.

The gear pump of the present embodiment is further provided with a cam 62 and a piston elastic member 63. The cam 62 is coaxially and fixedly connected with the driving gear 31, and the high-pressure piston 61 is slidably connected with the pump body 1 along the radial direction of the driving gear 31 and is in sliding contact with the outer circumferential surface of the cam 62. The piston elastic member 63 is a coil spring and is located between the high pressure piston 61 and the pump body 1 to drive the high pressure piston 61 to be held in sliding connection with the cam 62.

At the moment, along with the rotation of the driving gear, the high-pressure piston can be driven to reciprocate through the cam and the piston elastic piece, so that the high-pressure fluid is continuously output along with the rotation of the driving gear, the control effect of automatically introducing the high-pressure fluid into the first control cavity and the second control cavity is achieved, and the control effect of the gear pump is improved. Of course, in other embodiments, the high-pressure piston may be controlled to output the high-pressure fluid along with the rotation of the driving gear in other manners, for example, a piston pump may be used to output the high-pressure fluid along with the rotation of the driving gear, and even the external high-pressure fluid may be directly introduced into the first control cavity and the second control cavity to control the movement of the first side plate and the second side plate.

As shown in fig. 3, the gear pump of the present embodiment is further provided with a first check valve 71 and a second check valve 72. A first check valve 71 is located in the supply passage 163 to control the one-way flow of low pressure fluid to the high pressure piston 61. A second check valve 72 is located in the high pressure passage 161 to control the one-way outflow of the high pressure fluid from the high pressure piston 61.

At this time, the first check valve and the second check valve are constructed in a shuttle valve structure, so that automatic introduction and output of low-pressure fluid and high-pressure fluid are realized along with the reciprocating movement of the high-pressure piston. Of course, the communication relationship between the low-pressure fluid and the high-pressure fluid and the outlet end of the high-pressure piston can be controlled by arranging a reversing valve, so that the low-pressure fluid and the high-pressure fluid can be introduced and output.

As shown in fig. 1 to fig. 7, in the gear pump of the present embodiment, a positioning member 8 is further provided, and positioning grooves 44 are respectively provided on the first side plate 41 and the second side plate 42. The positioning member 8 is slidably connected to the pump body 1 and can move relative to the pump body 1 to engage with the positioning groove 44, so as to fix the first side plate 41 and the second side plate 42 at positions close to the driving gear 31 and the driven gear 32, respectively.

Like this, just can guarantee the normal working process of this gear pump with the help of the setting element, the accurate stability of first curb plate and second curb plate position avoids the unexpected slip of first curb plate and second curb plate and influences the normal work of whole gear pump.

Wherein, the positioning member 8 comprises a positioning piston 81 and a positioning elastic member 82. The positioning elastic element 82 is a coil spring, and is located between the pump body 1 and one end of the positioning piston 81 to drive the positioning piston 81 to move to a position where the positioning piston is disconnected from the positioning groove 44, that is, to fix the positions of the first side plate and the second side plate by the contact positioning element. The other end of the positioning piston 81 is directly communicated with the high-pressure flow passage 161, so that the high-pressure fluid is guided to the positioning piston 81 to overcome the acting force of the positioning elastic member 82, and then the connection with the positioning groove 44 is realized.

Of course, in other embodiments, the external control fluid may be introduced to drive the positioning piston to overcome the acting force of the positioning elastic element, so that the external control fluid cooperates with the positioning elastic element to achieve fixed control of the positions of the first side plate and the second side plate.

As shown in fig. 1 to 7, the gear pump of the present embodiment is further provided with a relief valve 9. The inlet of the relief valve 9 communicates with the first pilot chamber 151 and the second pilot chamber 152, and the outlet of the relief valve 9 communicates with the inlet 11. Therefore, the pressure of high-pressure fluid in the first control cavity and the second control cavity can be limited through the overflow valve, and the influence on the normal work of the gear pump due to overhigh pressure is avoided.

In this embodiment, an inlet of the overflow valve is communicated with the first control chamber and the second control chamber via a low-pressure flow passage, that is, the low-pressure flow passage adopts a three-way flow passage structure, one end of the low-pressure flow passage is communicated with the inlet via a connecting flow passage, the other end of the low-pressure flow passage is communicated with the inlet via the overflow valve, and the other end of the low-pressure flow passage is communicated with the first control chamber and the second control chamber. In other embodiments, the flow channel can of course be completely reconfigured for the connection between the overflow valve and the first and second control chambers and the inlet.

In addition, in the present embodiment, the first side plate and the second side plate effect reciprocating movement with respect to the pump body by the interaction of the high-pressure fluid and the elastic member. Of course, in other embodiments, the reciprocating movement of the first side plate and the second side plate may be controlled in other manners, for example, by using the electric pole, and the precise adjustment of the reciprocating movement distance of the first side plate and the second side plate may also be realized by controlling the expansion and contraction of the electric pole.

In addition, set up two curb plates in the gear pump of this embodiment, first curb plate and second curb plate promptly to be located driving gear and driven gear's axial both ends respectively, thereby realize the adjustment to distance between driving gear and the driven gear axial two terminal surfaces and the pump body inner wall. Of course, in other embodiments, only one side plate may be provided according to design and use conditions, and even the side plate is provided only for the driving gear or the driven gear, so as to meet different use requirements.

In this embodiment, the cam and the rotary disk are respectively and fixedly connected with the driving gear and the driven gear in a coaxial manner, and the fixed connection relationship between the cam and the rotary disk and the driving gear and the driven gear can be exchanged, even the cam and the rotary disk are fixedly connected to the driving gear or the driven gear.

Referring to fig. 1 to 7, the gear pump of the present embodiment performs a high-pressure fluid output operation in the following specific process:

when the gear pump is in the stop state, the pump shaft 2 is kept stationary, so that the drive gear 31, the driven gear 32, the dial 51, and the cam 62 are all kept stationary. At this time, the slider 52 is moved by the slider elastic member 53 relative to the rotary disk 51 to a position where the connection flow passage 511 is kept in a passage state, so that the low pressure flow passage 162 is kept in a communication relationship, that is, the first control chamber 151 and the second control chamber 152 are respectively kept in communication with the inlet 11 through the low pressure flow passage 162, and the first side plate 41 and the second side plate 42 are respectively moved to positions away from the driving gear 31 and the driven gear 32 by the elastic member 43. Meanwhile, the positioning member 8 is held in the non-connecting position with the first side plate 41 and the second side plate 42 by the positioning elastic member 82.

When the gear pump is started to work, the pump shaft 2 starts to drive the driving gear 31 to rotate, the driving gear 31 simultaneously drives the driven gear 32 and the cam 62 to rotate, and the driven gear 32 simultaneously drives the turntable 51 to rotate.

When the rotation speed of the pump shaft 2 is low, so that the centrifugal force generated by the rotation of the slider 52 with the rotating disc 51 cannot overcome the acting force of the slider elastic member 53, the low pressure flow passage 162 keeps the first control chamber 151 and the second control chamber 152 in a communication relationship with the inlet 11 through the connecting flow passage 511, and the high pressure piston 61, under the combined action of the cam 62 and the piston elastic member 63, introduces low pressure fluid from the inlet 11 through the liquid supply flow passage 163 and the first check valve 71, applies work and increases pressure, and flows to the first control chamber 151 and the second control chamber 152 through the second check valve 72 and the high pressure flow passage 161, and also flows back to the inlet 11 through the low pressure flow passage 162, so that the first side plate 41 and the second side plate 42 are kept at positions far away from the driving gear 31 and the driven gear 32. Thus, the gear pump is in an idle state, and fluid flows into axial end surfaces of the drive gear 31 and the driven gear 32, thereby achieving a full lubrication effect on the drive gear 31 and the driven gear 32.

When the rotation speed of the pump shaft 2 is increased, so that the centrifugal force generated by the rotation of the rotary disc 51 by the slider 52 can overcome the action force of the slider elastic member 53 to start relative movement with respect to the rotary disc 51, the slider 52 moves to a position where the connection flow passage 511 is cut off, thereby cutting off the communication relationship between the first control chamber 151 and the second control chamber 152 with the inlet 11. At this time, the high pressure piston 61, under the combined action of the cam 62 and the piston elastic member 63, introduces the low pressure fluid from the inlet 11 through the liquid supply passage 163 and the first check valve 71 and performs work to increase the pressure, and the pressure of the high pressure fluid flowing to the first control chamber 151 and the second control chamber 152 through the second check valve 72 and the high pressure passage 161 starts to gradually increase. When the pressure of the high-pressure fluid in the first control chamber 151 and the second control chamber 152 can drive the first side plate 41 and the second side plate 42 to overcome the acting force of the elastic piece 43, the first side plate 41 and the second side plate 42 are driven to move towards the direction close to the driving gear 31 and the driven gear 32 until the first side plate 41 and the second side plate 42 move to the right position. At this time, the positioning grooves 44 on the first side plate 41 and the second side plate 42 are aligned with the positioning piston 81, and the positioning piston 81 extends into the positioning groove 44 under the action of the high-pressure fluid in the high-pressure flow passage 161 against the action force of the positioning elastic member 82, so as to form the position positioning of the first side plate 41 and the second side plate 42, thereby the gear pump enters into the normal operation process. After a part of the high-pressure fluid enters the first control chamber 151 and the second control chamber 152 through the high-pressure flow passage 161, the high-pressure fluid flows to the two positioning members 8 at the lower position in fig. 1 through the low-pressure flow passage 162 between the connection flow passage 511 and the relief valve 9 and between the first control chamber 151 and the second control chamber 152, so that the positioning of the first side plate 41 and the second side plate 42 by the four positioning members 8 is realized.

In the process, the high-pressure piston 61 continuously outputs the high-pressure fluid, and when the pressure of the high-pressure fluid in the first control chamber 151 and the second control chamber 152 exceeds the set pressure of the relief valve 9, the relief valve 9 opens and relieves the high-pressure fluid in the first control chamber 151 and the second control chamber 152 to the inlet 11, so that the pressure of the high-pressure fluid in the first control chamber 151 and the second control chamber 152 is maintained at the set pressure value of the relief valve 9.

When the gear pump is stopped again, the pump shaft 2 stops rotating, and the drive gear 31, the driven gear 32, and the dial 51 all stop rotating. At this time, the slider 52 loses centrifugal force and moves to a position where the connection flow passage 511 is kept in a passage state relative to the rotary disc 51 under the action of the slider elastic member 53, so that the low pressure flow passage 162 is re-in the passage state, the high pressure medium in the first control chamber 151 and the second control chamber 152 flows back to the inlet 11 through the low pressure flow passage 162, and the stop rotation of the cam 62 stops the high pressure piston 61 from outputting high pressure fluid, so that the positioning piston 81 moves to a position where the positioning piston is separated from the insertion connection with the positioning groove 44, namely, the position where the first side plate 41 and the second side plate 42 are in contact with and locked with each other, and the first side plate 41 and the second side plate 42 move to positions away from the driving gear 31 and the driven gear 32 respectively under the action of the positioning elastic member 82.

Claims

1. A gear pump is characterized by comprising a pump body, a pump shaft, a driving gear, a driven gear and a side plate; the pump body is provided with an inlet and an outlet; the driving gear and the driven gear are positioned in the pump body in a tooth meshing manner, and form a liquid inlet cavity communicated with the inlet and a liquid outlet cavity communicated with the outlet; the pump shaft is coaxially connected with the driving gear so as to drive the driving gear to rotate; the side plates are positioned in the pump body and positioned between the axial end surface of the driving gear and the inner wall of the pump body and between the axial end surface of the driven gear and the inner wall of the pump body; the side plate can move back and forth relative to the driving gear and the driven gear along the axial direction of the driving gear;

the gear pump is also provided with an elastic piece; a control cavity is formed between the side plate and the inner wall of the pump body and is used for containing high-pressure fluid to drive the side plate to move towards the direction close to the driving gear and the driven gear; the elastic piece is positioned between the side plate and the driving gear and/or the driven gear so as to drive the side plate to move towards the direction away from the driving gear and the driven gear;

the gear pump is provided with a high-pressure flow passage and a low-pressure flow passage; one end of the high-pressure flow passage is communicated with high-pressure fluid, and the other end of the high-pressure flow passage is communicated with the control cavity; one end of the low-pressure flow passage is communicated with the control cavity, and the other end of the low-pressure flow passage is selectively communicated with low-pressure fluid;

the gear pump is provided with a rotary table, a sliding block and a sliding block elastic piece; the rotary disc is coaxially and fixedly connected with the driving gear or the driven gear, a connecting flow channel is arranged on the rotary disc, and the low-pressure flow channel penetrates through the connecting flow channel; the sliding block is eccentrically arranged on the rotary disc and can slide in a reciprocating manner relative to the rotary disc along the diameter direction of the rotary disc; the sliding block elastic piece is positioned between the sliding block and the rotating disc so as to drive the sliding block to move to a position for cutting off the connecting flow channel relative to the rotating disc;

the gear pump is provided with a liquid supply flow passage and a high-pressure piston; the high-pressure piston is connected with the driving gear or the driven gear to perform reciprocating movement; the liquid supply channel is communicated with low-pressure fluid, the output end of the high-pressure piston is respectively and selectively communicated with the liquid supply channel and the high-pressure channel, and the low-pressure fluid is introduced from the liquid supply channel and is output to the high-pressure channel.

2. Gear pump according to claim 1, characterized in that it is provided with cam and piston elastic elements; the cam is coaxially and fixedly connected with the driving gear or the driven gear, and the high-pressure piston is in sliding connection with the pump body along the radial direction of the driving gear and is in sliding contact with the cam; the piston elastic piece is positioned between the high-pressure piston and the pump body so as to drive the high-pressure piston to be kept in a sliding connection state with the cam.

3. Gear pump according to claim 1, characterized in that it is provided with a first and a second check valve; the first check valve is positioned in the liquid supply flow channel to control the low-pressure fluid to flow to the high-pressure piston in a one-way mode; the second check valve is positioned in the high-pressure flow passage to control high-pressure fluid to flow out of the high-pressure piston.

4. Gear pump according to claim 1, characterized in that it is provided with an overflow valve; the overflow valve is positioned between the control cavity and the low-pressure fluid and is used for controlling the highest pressure of the high-pressure fluid in the control cavity.

5. Gear pump according to claim 1, characterized in that it is provided with positioning elements and in that the side plates are provided with positioning slots; the positioning piece is connected with the pump body in a sliding mode, can move relative to the pump body to be connected with the positioning groove, and fixes the side plate at a position close to the driving gear and the driven gear.

6. The gear pump of claim 5, wherein the positioning member comprises a positioning piston and a positioning resilient member; the positioning elastic piece is positioned between the pump body and one end of the positioning piston so as to drive the positioning piston to move to a position where the positioning piston is separated from being connected with the positioning groove; the other end of the positioning piston is communicated with a control fluid to drive the positioning piston to overcome the positioning elastic piece to move to a position connected with the positioning groove.