CN216342783U

CN216342783U - Gear pump constant-flow structure

Info

Publication number: CN216342783U
Application number: CN202123074956.0U
Authority: CN
Inventors: 江津红
Original assignee: Wenling Fuli Pump Industry Co ltd
Current assignee: Wenling Fuli Pump Industry Co ltd
Priority date: 2021-12-07
Filing date: 2021-12-07
Publication date: 2022-04-19
Anticipated expiration: 2031-12-07

Abstract

The utility model provides a gear pump constant-current structure, and belongs to the technical field of machinery. It has solved the current not good problem of overflow valve job stabilization nature. The constant-current structure of the gear pump comprises a pump body provided with a high-pressure cavity, a negative-pressure cavity, a valve hole, a throttling hole, a damping hole and an oil outlet hole, wherein two ends of the damping hole are respectively communicated with the right end of the valve hole and the oil outlet hole, the lower end of the throttling hole is communicated with the oil outlet hole, the left end of the valve hole, the upper end of the high-pressure cavity and the upper end of the throttling hole are communicated, the middle part of the valve hole is provided with an overflow hole communicated with the negative-pressure cavity and a valve core for controlling the opening and closing of the overflow hole, the right end of the valve hole is provided with a first spring for enabling the valve core to move to the left, the right end of the valve core is screwed with a valve seat, a second spring for enabling a sealing piece to have the trend of plugging the left end of the valve seat is arranged in the valve core, two ends of the first spring are respectively pressed on the inner walls of the right end face and the right end face of the valve core, a guide sleeve is sleeved outside the guide sleeve, a limiting part is arranged on the valve seat, and the guide sleeve is clamped and positioned between the limiting part and the valve core. The constant-flow structure of the gear pump works stably.

Description

Gear pump constant-flow structure

Technical Field

The utility model belongs to the technical field of machinery, and relates to a gear pump, in particular to a constant-flow structure of the gear pump.

Background

Gear pumps are rotary pumps that deliver or pressurize fluid by virtue of the change in working volume and movement created between a pump cylinder and a meshing gear. Two gears, pump body and front and back covers form two closed spaces, when the gears rotate, the space on the gear disengagement side becomes larger from smaller to larger to form vacuum to suck liquid, and the space on the gear engagement side becomes smaller from larger to smaller to squeeze liquid into the pipeline.

In order to ensure the stability of output pressure, some gear pumps are internally provided with constant-flow structures, for example, a constant-flow overflow valve (application number: 201721122951.1) for the gear pump disclosed in Chinese patent library, which comprises a valve body, a first adjusting gasket, a second adjusting gasket, a first sealing gasket, a second sealing gasket and a control spring, and is characterized in that the valve body is respectively provided with an oil outlet, an oil passing hole, a throttling hole, a valve hole, an oil outlet cavity through hole and an oil drain hole, one end of the oil passing hole and one end of the throttling hole are respectively communicated with the oil outlet, the other end of the oil passing hole and the other end of the throttling hole are respectively communicated with the valve hole, the left end of the valve hole is in threaded connection with a spring plug, the spring plug and the valve body are sealed by the second sealing gasket, the second adjusting gasket is arranged in the internal control of the spring plug, one end of the control spring is pressed on the right side surface of the adjusting gasket, and the other end of the control spring is pressed on the shoulder on the right side of the damping valve seat, the damping valve seat is arranged in an inner hole of the constant flow valve core in a penetrating manner, the constant flow valve core is arranged in the valve hole in a penetrating manner, the conical valve is arranged in the inner hole of the constant flow valve core, the left end of the conical valve is arranged in a center hole of the right end face of the damping valve seat, the right end of the conical valve is sleeved with an adjusting gasket I, the conical valve on the right side of the adjusting gasket I is sleeved with a pressure limiting spring, one end of the pressure limiting spring is arranged on the right end face of the adjusting gasket I, the other end of the pressure limiting spring is pressed on the inner end face of the hole in the right end of the constant flow valve core, the right end of the valve hole is in threaded connection with a high-pressure oil plug, and the high-pressure oil plug and the valve body are sealed through a sealing gasket I.

In the overflow valve, one end of the control spring acts on the damping valve seat, and the damping valve seat is connected with the constant flow valve core through threads, so that the displacement probability of the damping valve seat exists during working, the compression amount of the control spring is changed, and the adjustment precision is influenced.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the problems in the prior art and provides a gear pump constant-flow structure which is stable in working.

The purpose of the utility model can be realized by the following technical scheme: a constant-current structure of a gear pump comprises a pump body provided with a high-pressure cavity, a negative-pressure cavity, a valve hole, a throttling hole, a damping hole and an oil outlet, wherein the upper end and the lower end of the damping hole are respectively communicated with the right end and the oil outlet of the valve hole, the lower end of the throttling hole is communicated with the oil outlet, the left end of the valve hole, the high-pressure cavity and the upper end of the throttling hole are mutually communicated, the middle part of the valve hole is provided with an overflow hole communicated with the negative-pressure cavity and a barrel-shaped valve core for controlling the opening and closing of the overflow hole, the right end of the valve hole is provided with a first spring for enabling the valve core to have a left-moving trend, the right end of the valve core is screwed with a tubular valve seat, the right end of the valve seat extends out of the valve core, a sealing element and a second spring for enabling the sealing element to have a trend of plugging the left end of the valve seat are arranged in the valve core, the two ends of the first spring are respectively pressed against the inner walls of the right end face and the right end face of the valve core, a guide sleeve matched with a guide sleeve is sleeved outside the valve seat, and a limiting element in an annular shape, and the guide sleeve is clamped and positioned between the limiting part and the valve core.

The using process is as follows: the gear pump increases the volume of the negative pressure cavity through the rotation of the gear to generate negative pressure, hydraulic oil enters the negative pressure cavity, the hydraulic oil enters the high pressure cavity through the rotation of the gear, and then the hydraulic oil is discharged into the oil outlet through the throttling hole; when the rotation speed of the gear pump is increased to the extent that the valve core overcomes the elastic force of the spring and moves right to enable the overflow hole to be communicated with the left end of the valve hole, hydraulic oil in the left end of the valve hole can flow back to the negative pressure cavity through the overflow hole, the overflow amount is gradually increased along with the gradual increase of the rotation speed, and the flow discharged through the throttling hole is kept constant; when the discharge pressure is higher than the specified pressure, the sealing element overcomes the elastic force of the spring to move left to open the valve seat, so that the right end of the valve hole is communicated with the inner cavity of the valve core to promote the pressure at the right end of the valve hole to be reduced, at the moment, the pressure at the left end of the valve hole is higher than the pressure at the right end of the valve hole, the valve core is pushed to overcome the elastic force of the spring to move right to enable the overflow hole to be communicated with the left end of the valve hole, hydraulic oil is enabled to flow back to the negative pressure cavity through the overflow hole to carry out internal circulation, and the gear pump is enabled to be kept at the highest discharge pressure.

Two ends of a first spring are respectively pressed on the right end face of the valve core and the inner wall of the right end of the valve hole, and the end face of the valve core and the inner wall of the valve hole are both fixed faces, so that the first spring is ensured to perform telescopic motion in a constant interval all the time, and the adjustment precision is improved; meanwhile, a guide sleeve matched with the spring I is arranged on the inner side of the spring I and used for telescopic guiding of the spring I so as to improve telescopic precision and stability, and therefore adjustment precision is further improved.

Simultaneously, the guide pin bushing both had been used for the flexible direction of spring one, was used for spacing disk seat again, and in this application, the guide pin bushing possesses the dual-purpose effect of an thing promptly, when simplifying the structure, the equipment of being convenient for again.

In foretell gear pump constant current structure, foretell locating part includes gasket and integrated into one piece annular convex shoulder on the disk seat outer wall, and the gasket cover is on the disk seat, and gasket both ends face sticiss respectively on guide pin bushing and annular convex shoulder, can adjust disk seat mounted position through the gasket of changing different thickness like this, realizes that the different compression capacities of spring two match different operating modes, and the practicality is better.

As another scheme, in the gear pump constant-flow structure, the limiting member is an annular limiting seat integrally formed on the outer wall of the valve seat.

In the gear pump constant-flow structure, the sealing element is rod-shaped and is coaxially arranged with the valve seat, and the right end of the sealing element can extend into the valve seat to block the left port of the valve seat under the action of the spring II.

In the gear pump constant-flow structure, the right end of the sealing element is in a solid conical shape, the inner wall of the valve seat is provided with a conical surface matched with the right end of the sealing element, and the side wall of the right end of the sealing element is in close contact with the conical surface to form sealing, so that the effect of sealing the valve seat by the sealing element is improved, and the working stability is improved.

As another scheme, in the gear pump constant-flow structure, the sealing element is in a block shape, and the sealing element is tightly pressed on the left end face of the valve seat to close the left port of the valve seat.

In the gear pump constant-current structure, a through hole penetrates horizontally from left to right on the pump body, two ports of the through hole are sealed by plugs, the plugs are fixedly connected with the pump body, and the valve hole is formed between the through hole and the two plugs so as to facilitate the installation of the components such as the valve core, the sealing element, the spring I and the spring II.

In foretell gear pump constant current structure, the end cap is including being cylindrical main part, and the main part is inserted in the through-hole and is linked firmly with the pump body, and the through-hole is stretched out to the main part outer end, and the shaping has the annular to keep off the shoulder on the outer wall of main part outer end, and the annular keeps off the shoulder and forms sealedly through sealed the pad of annular and the pump body.

In the gear pump constant-current structure, the annular sealing gasket is sleeved outside the main body, two end faces of the annular sealing gasket are respectively pressed on the outer wall of the pump body and the annular blocking shoulder, the supporting ring made of rigid material is fixedly arranged between the annular blocking shoulder and the pump body, the annular sealing gasket is positioned between the supporting ring and the main body, and the outer side wall of the annular sealing gasket is attached to the inner side wall of the supporting ring. The support ring is used for radially supporting the annular sealing gasket, the compressive property of the annular sealing gasket is enhanced, the end cap is ensured to always seal the port of the through hole, and the working stability is improved.

In the gear pump constant-flow structure, two end faces of the support ring are respectively tightly pressed on the annular retaining shoulder and the pump body, namely the support ring is positioned in a clamping mode, so that the assembly is convenient.

In the gear pump constant-current structure, the outer wall of the main body is formed with the annular convex part, the inner side wall of the annular sealing gasket is provided with the annular groove matched with the annular convex part, and the annular convex part is inserted into the annular groove. The annular groove and the annular convex part are matched to limit the annular sealing gasket in the axial direction, so that the pressure resistance of the annular sealing gasket is improved by reinforcing and positioning the annular sealing gasket.

In the gear pump constant-current structure, one main body is provided with a concave cavity matched with the first spring, the right end of the first spring extends into the concave cavity and presses the bottom wall of the concave cavity, the other main body is solid, and the left end of the valve core has a tendency of pressing the other main body under the action of the first spring.

Compared with the prior art, the gear pump constant-flow structure has the following advantages:

1. two ends of a first spring are respectively pressed on the right end face of the valve core and the inner wall of the right end of the valve hole, and the end face of the valve core and the inner wall of the valve hole are both fixed faces, so that the first spring is ensured to perform telescopic motion in a constant interval all the time, and the adjustment precision is improved; meanwhile, a guide sleeve matched with the spring I is arranged on the inner side of the spring I and used for telescopic guiding of the spring I so as to improve telescopic precision and stability, and therefore adjustment precision is further improved.

2. The guide pin bushing both has been used for the flexible direction of spring one, is used for spacing disk seat again, and in this application promptly, the guide pin bushing possesses the dual-purpose effect of an thing, when simplifying the structure, the equipment of being convenient for again.

3. The valve seat mounting position is adjusted by replacing gaskets with different thicknesses, different compression amounts of the second spring are matched with different working conditions, and the practicability is good.

Drawings

Fig. 1 is a schematic sectional structure view of a gear pump.

FIG. 2 is a schematic sectional view A-A of FIG. 1.

Fig. 3 is an enlarged schematic view of a structure at a in fig. 2.

Fig. 4 is an enlarged schematic view of B in fig. 3.

Fig. 5 is a front view schematic of a gear pump.

In the figure, 1, a pump body; 1a, a high-pressure cavity; 1b, a valve hole; 1c, an orifice; 1d, a damping hole; 1e, oil outlet holes; 1f, an oil inlet hole; 1g of overflow hole; 2. a valve core; 2a, a sealing part; 3. a first spring; 4. a valve seat; 4a, an annular shoulder; 5. a seal member; 6. a second spring; 7. a plug; 7a, a main body; 7b, an annular shoulder; 7c, an annular projection; 8. an annular seal; 9. a support ring; 10. a guide sleeve; 11. and (7) a gasket.

Detailed Description

The following are specific embodiments of the present invention and are further described with reference to the drawings, but the present invention is not limited to these embodiments.

As shown in fig. 1, 2 and 5, the constant flow structure of the gear pump comprises a pump body 1, wherein a high pressure cavity 1a, a negative pressure cavity, a valve hole 1b, an orifice 1c, a damping hole 1d, an oil outlet hole 1e and an oil inlet hole 1f are arranged in the pump body 1.

Wherein,

two meshed gear shafts are arranged in the pump body 1, the pump cavity of the pump body 1 is divided into a high-pressure cavity 1a and a negative-pressure cavity by the two gear shafts, and the high-pressure cavity 1a and the negative-pressure cavity are meshed and communicated through the gear shafts.

One end of the oil inlet hole 1f is communicated with the negative pressure cavity; the valve hole 1b and the oil outlet hole 1e are both strip-shaped, and in an actual product, the valve hole 1b and the oil outlet hole 1e are arranged in parallel up and down; the upper end and the lower end of the damping hole 1d are respectively communicated with the right end of the valve hole 1b and the oil outlet 1 e; the lower end of the orifice 1c is communicated with the oil outlet 1e, and the left end of the valve hole 1b, the high-pressure cavity 1a and the upper end of the orifice 1c are communicated with each other.

As shown in fig. 2, the middle of the valve hole 1b is provided with an overflow hole 1g communicated with the negative pressure cavity and a barrel-shaped valve core 2 for controlling the opening and closing of the overflow hole 1 g. The left end of the valve core 2 is closed, the right end of the valve core 2 is opened, the right end of the valve hole 1b is provided with a first spring 3 which enables the valve core 2 to have a left moving trend, the right end of the valve core 2 is in threaded connection with a tubular valve seat 4, the right end of the valve seat 4 extends out of the valve core 2, a sealing part 5 is arranged in the valve core 2, and a second spring 6 which enables the sealing part 5 to have a trend of plugging the left end of the valve seat 4 is arranged in the sealing part 5.

In particular, the present invention relates to a method for producing,

the valve hole 1b is formed as follows: the horizontal through-hole that has run through about on the pump body 1, through-hole both ends mouth all seals through end cap 7, and end cap 7 links firmly with the pump body 1, and forms foretell valve opening 1b between through-hole and two end caps 7. Wherein, end cap 7 is including being cylindrical main part 7a, and main part 7a inserts in the through-hole and links firmly with the pump body 1, and the through-hole is stretched out to main part 7a outer end, and the shaping has annular to keep off shoulder 7b on the outer wall of main part 7a outer end, and annular keeps off shoulder 7b and forms sealedly through annular sealed pad 8 and pump body 1 between. In this embodiment, it is preferable that the main body 7a and the through hole are fixedly connected by screw threads; the annular sealing gasket 8 is sleeved outside the main body 7a, and two end faces of the annular sealing gasket 8 are respectively pressed on the outer wall of the pump body 1 and the annular retaining shoulder 7 b.

To explain further, as shown in fig. 3 and 4, a supporting ring 9 made of a rigid material is further fixedly arranged between the annular retaining shoulder 7b and the pump body 1, the annular sealing gasket 8 is located between the supporting ring 9 and the main body 7a, and an outer side wall of the annular sealing gasket 8 abuts against an inner side wall of the supporting ring 9. The support ring 9 is used for radially supporting the 9-shaped sealing gasket 8 of the ring-shaped sealing gasket, the pressure resistance of the 8-shaped sealing gasket is enhanced, the plug 7 is ensured to always seal the port of the through hole, and the working stability is improved. An annular convex part 7c is formed on the outer wall of the main body 7a, an annular groove matched with the annular convex part 7c is formed in the inner side wall of the annular sealing gasket 8, and the annular convex part 7c is inserted into the annular groove. The annular groove and the annular protrusion 7c cooperate to axially restrain the annular packing 8 to improve the pressure resistance thereof by reinforcing the positioning of the annular packing 8. Preferably, the support ring 9 is made of plastic or stainless steel material, and two end faces of the support ring 9 are respectively pressed on the annular retaining shoulder 7b and the pump body 1, i.e. the support ring 9 is positioned in a clamping manner, so that the assembly is facilitated.

As shown in fig. 2 and 3, two ends of the first spring 3 are respectively abutted against the inner walls of the right end face of the valve element 2 and the right end of the valve hole 1b, a guide sleeve 10 matched with the first spring 3 is sleeved outside the valve seat 4, the left end of the first spring 3 is sleeved outside the guide sleeve 10, an annular limiting part is arranged on the valve seat 4, and the guide sleeve 10 is clamped and positioned between the limiting part and the valve element 2.

In the present embodiment, it is preferred that,

a concave cavity matched with the first spring 3 is formed in the main body 7a on the right side, and the right end of the first spring 3 extends into the concave cavity and is pressed on the bottom wall of the concave cavity; the other body 7a is solid, and the left end of the valve core 2 tends to press on the other body 7a under the action of the first spring 3.

Have on the 2 outer walls of case and be annular sealing part 2a, sealing part 2a has two and along 2 axial distributions of case, and two sealing part 2a all form sealedly through sealing washer and through-hole inner wall to when 2 left ends of case have the pressure on corresponding main part 7a, overflow hole 1g is in between two sealing part 2a, makes overflow hole 1g all not communicate valve hole 1b both ends.

The locating part includes gasket 11 and integrated into one piece annular convex shoulder 4a on the outer wall of

disk seat

4, and 11 covers of gasket are on

disk seat

4, and 11 both ends faces of gasket are sticis respectively on guide pin bushing 10 and annular convex shoulder 4a, can adjust disk seat 4 mounted position through the gasket 11 of changing different thickness like this, realize that the different compression capacities of spring two 6 match different operating modes, and the practicality is better.

The sealing element 5 is rod-shaped and is coaxially arranged with the valve seat 4, the second spring 6 is sleeved outside the sealing element 5, two ends of the second spring 6 are respectively pressed on the inner wall of the valve core 2 and the sealing element 5, and under the action of the second spring 6, the right end of the sealing element 5 can extend into the valve seat 4 to plug the left port of the valve seat 4.

Further, the right end of the sealing element 5 is in a solid conical shape, a conical surface matched with the right end of the sealing element 5 is arranged on the inner wall of the valve seat 4, and the side wall of the right end of the sealing element 5 is in close contact with the conical surface to form sealing, so that the effect of sealing the valve seat 4 by the sealing element 5 is improved, and the working stability is improved.

The using process is as follows: the gear pump increases the volume of the negative pressure cavity through the rotation of the gear to generate negative pressure, hydraulic oil enters the negative pressure cavity, the hydraulic oil enters the high pressure cavity 1a through the rotation of the gear, and then the hydraulic oil is discharged into the oil outlet 1e through the throttling hole 1 c; when the rotation speed of the gear pump is increased to the extent that the valve core 2 overcomes the elastic force of the first spring 3 and is moved away to the right to open the overflow hole 1g, hydraulic oil in the left end of the valve hole 1b flows back to the negative pressure cavity through the overflow hole 1g, and the overflow amount is gradually increased along with the gradual increase of the rotation speed, so that the flow discharged through the throttling hole 1c is kept constant; when the discharge pressure is higher than the specified pressure, the sealing element 5 overcomes the elasticity of the second spring 6 to move left to open the valve seat 4, so that the right end of the valve hole 1b is communicated with the inner cavity of the valve core 2 to promote the pressure of the right end of the valve hole 1b to be reduced, at the moment, the pressure of the left end of the valve hole 1b is higher than the pressure of the right end of the valve hole 1b, the valve core 2 is pushed to move right to overcome the elasticity of the first spring 3 to enable the overflow hole 1g to be communicated with the left end of the valve hole 1b, hydraulic oil is enabled to flow back to the negative pressure cavity through the overflow hole 1g to carry out internal circulation, and the gear pump is enabled to be kept at the highest discharge pressure.

Example two

The structure and principle of the second embodiment are basically the same as those of the first embodiment, and different points are as follows: the limiting part is an annular limiting seat which is integrally formed on the outer wall of the valve seat 4.

EXAMPLE III

The structure and principle of the third embodiment are basically the same as those of the first embodiment, and different points are as follows: the sealing element 5 is in a block shape, and the sealing element 5 is tightly pressed on the left end face of the valve seat 4 to close the left port of the valve seat 4.

The specific embodiments described herein are merely illustrative of the spirit of the utility model. Various modifications or additions may be made to the described embodiments or alternatives may be employed by those skilled in the art without departing from the spirit or ambit of the utility model as defined in the appended claims.

Claims

1. A gear pump constant-current structure comprises a pump body (1) provided with a high-pressure cavity (1a), a negative-pressure cavity, a valve hole (1b), a throttling hole (1c), a damping hole (1d) and an oil outlet (1e), wherein the upper end and the lower end of the damping hole (1d) are respectively communicated with the right end and the oil outlet (1e) of the valve hole (1b), the lower end of the throttling hole (1c) is communicated with the oil outlet (1e), the left end of the valve hole (1b), the high-pressure cavity (1a) and the upper end of the throttling hole (1c) are communicated with each other, the middle part of the valve hole (1b) is provided with an overflow hole (1g) communicated with the negative-pressure cavity and a barrel-shaped valve core (2) for controlling the overflow hole (1g) to open and close, the right end of the valve hole (1b) is provided with a spring I (3) for enabling the valve core (2) to have a left-moving trend, the right end of the valve core (2) is screwed with a pipe-shaped valve seat (4), and the right end of the valve seat (4) extends out of the valve core (2), be equipped with sealing member (5) in case (2) and make sealing member (5) have spring two (6) of shutoff disk seat (4) left end mouth trend, its characterized in that, the both ends of spring one (3) support respectively and press on case (2) right-hand member terminal surface and valve opening (1b) right-hand member inner wall, disk seat (4) overcoat has guide pin bushing (10) that matches with spring one (3), and the left end cover of spring one (3) is outside guide pin bushing (10), be equipped with on disk seat (4) and be annular locating part, and guide pin bushing (10) press from both sides tightly the location between locating part and case (2).

2. The gear pump constant-flow structure as claimed in claim 1, wherein the limiting member comprises a gasket (11) and an annular shoulder (4a) integrally formed on the outer wall of the valve seat (4), the gasket (11) is sleeved on the valve seat (4), and two end faces of the gasket (11) are respectively pressed on the guide sleeve (10) and the annular shoulder (4 a).

3. Gear pump constant flow structure according to claim 1 or 2, characterized in that the sealing element (5) is rod-shaped and is arranged coaxially with the valve seat (4), and under the action of the second spring (6), the right end of the sealing element (5) can extend into the valve seat (4) to block the left port of the valve seat (4).

4. The gear pump constant flow structure of claim 3, wherein the right end of the sealing element (5) is in a solid conical shape, the inner wall of the valve seat (4) is provided with a conical surface matched with the right end of the sealing element (5), and the side wall of the right end of the sealing element (5) is tightly contacted with the conical surface to form a seal.

5. The gear pump constant-flow structure according to claim 1, wherein a through hole is horizontally formed in the pump body (1) in a penetrating manner from left to right, two ports of the through hole are sealed by plugs (7), the plugs (7) are fixedly connected with the pump body (1), and the valve hole (1b) is formed between the through hole and the two plugs (7).

6. The gear pump constant-current structure as claimed in claim 5, wherein the plug (7) comprises a columnar main body (7a), the main body (7a) is inserted into the through hole and fixedly connected with the pump body (1), the outer end of the main body (7a) extends out of the through hole, an annular retaining shoulder (7b) is formed on the outer wall of the outer end of the main body (7a), and the annular retaining shoulder (7b) forms a seal with the pump body (1) through an annular sealing gasket (8).

7. The gear pump constant-flow structure according to claim 6, wherein the annular sealing gasket (8) is sleeved outside the main body (7a), two end faces of the annular sealing gasket (8) are respectively pressed on the outer wall of the pump body (1) and the annular retaining shoulder (7b), a support ring (9) made of rigid material is further fixedly arranged between the annular retaining shoulder (7b) and the pump body (1), the annular sealing gasket (8) is positioned between the support ring (9) and the main body (7a), and the outer side wall of the annular sealing gasket (8) is attached to the inner side wall of the support ring (9).

8. Gear pump constant flow structure according to claim 7, characterized in that the two end faces of the support ring (9) are pressed tightly against the annular shoulder (7b) and the pump body (1), respectively.

9. The gear pump constant-flow structure according to claim 7 or 8, wherein an annular convex part (7c) is formed on the outer wall of the main body (7a), an annular groove matched with the annular convex part (7c) is formed on the inner side wall of the annular sealing gasket (8), and the annular convex part (7c) is inserted in the annular groove.

10. Gear pump constant flow arrangement according to claim 6, characterized in that one of the bodies (7a) is provided with a cavity matching the first spring (3), the right end of the first spring (3) extends into the cavity and presses against the bottom wall of the cavity, the other body (7a) is solid and the left end of the spool (2) has a tendency to press against the other body (7a) under the action of the first spring (3).