CN115163483A

CN115163483A - Hydraulic gear pump

Info

Publication number: CN115163483A
Application number: CN202210962012.7A
Authority: CN
Inventors: 魏列江; 张生福; 黎义斌; 孟庆武; 张广志; 孙栋栋; 张志宇
Original assignee: Shandong Shijing Hydraulic Equipment Co ltd
Current assignee: Shandong Shijing Hydraulic Equipment Co ltd
Priority date: 2022-08-11
Filing date: 2022-08-11
Publication date: 2022-10-11

Abstract

The invention discloses a hydraulic gear pump which comprises a driving gear shaft, a lip-shaped sealing ring, a front end cover, a front 8-shaped sleeve, a pump body, a rear 8-shaped sleeve, a rear end cover, a driven gear shaft, a positioning pin hole, a pump outlet and a fixing bolt hole. Compared with the prior art, its beneficial effect is: dynamic compensation of radial force of the bearing is carried out, an oil film is formed between the rotating shafts, abrasion between the bearing and the shafts during rotation is avoided, and a dynamic pressure floating state of the rotating shafts is realized; the axial force generated when the spiral gear is rotationally meshed with a conveying medium is compensated, and the problem that the gear is axially moved under the action of the axial force is solved; the inclination caused by high and low pressure difference of the contact end surface of the gear is effectively relieved; an open loop is formed from high pressure to medium pressure and then to low pressure, dynamic high-pressure oil is introduced to keep constant dynamic pressure, high-temperature oil is taken away to reduce the internal temperature of the hydraulic gear pump, and the functions of lubrication and cooling are achieved.

Description

Hydraulic gear pump

Technical Field

The invention relates to the technical field of hydraulic gear pumps, in particular to a hydraulic gear pump.

Background

The hydraulic gear pump is widely applied to the high-end engineering fields such as national defense military industry, ship power, aerospace and aviation, walking machinery, medical equipment, heavy equipment and the like, is used as one of the most central parts for providing power for a hydraulic system, and the performance of the hydraulic gear pump directly determines the quality of the hydraulic system and influences the performance of the high-end engineering equipment. Gear pump leakage can influence gear pump volumetric efficiency, and the wearing and tearing of gear pump can directly or indirectly reduce volumetric efficiency, the working life of pump, produce noise etc.. The generated noise not only affects the service performance of the whole system, but also has certain adverse effect on physical and psychological health of people. Therefore, the hydraulic gear pump has the advantages of low leakage, low noise and low abrasion in work, and plays an important role in the safety and stability of the whole hydraulic system. Therefore, the mechanism of leakage, noise and abrasion generation must be known in the design stage of the hydraulic gear pump, and the leakage, abrasion and noise generation is prevented, so that the performance of the hydraulic gear pump is improved. Radial force, axial force and high-low pressure areas which can occur in the working process of the hydraulic gear pump are all reasons for abrasion and noise of the pump; the shaft and the bearing sleeve are seriously abraded under the condition of long-time work, and simultaneously, heat and noise are generated by rotation, so that the high-speed working condition cannot be realized; the heat generated inside the pump cannot be eliminated in time, the viscosity of the medium is changed, the performance of the pump is reduced, and leakage is increased. If can solve above problem together, can effectively solve the problem of revealing simultaneously, wearing and tearing and noise, at present, at home and abroad all develops the performance that hydraulic gear pump was promoted to a point to the main research of developing, but promotes the effect low, and the performance improvement to other problems is not obvious, can't accomplish to reduce revealing, wearing and tearing, the noise of gear pump and improve its life-span simultaneously high-efficiently.

Disclosure of Invention

The present invention is directed to a hydraulic gear pump to solve the above problems of the prior art.

In order to achieve the purpose, the invention provides the following technical scheme: the pump comprises a driving gear shaft, a lip-shaped sealing ring, a front end cover, a front 8-shaped sleeve, a pump body, a rear 8-shaped sleeve, a rear end cover, a driven gear shaft, a positioning pin hole, a pump outlet and a fixing bolt hole; the side surfaces of the front end cover and the rear end cover, which are in contact with the pump body, are provided with through 8-shaped through grooves, and sealing O-shaped rings are arranged in the through grooves; the front end cover is arranged on the left side of the pump body; the front 8-shaped sleeve is arranged on the left side in the pump body; the driving gear shaft penetrates through the front end cover and the front 8-shaped sleeve and is installed in the pump body, and the left side surface of the gear section of the driving gear shaft is contacted with the right side surface of the front 8-shaped sleeve; the rear 8-shaped sleeve is in contact with the right side of the gear section of the driving gear shaft and is positioned on the right side in the pump body; the driven gear shaft penetrates through the front 8-shaped sleeve and the rear 8-shaped sleeve and is arranged in the pump body, and a gear section of the driven gear shaft is meshed with a gear section of the driving gear shaft; the rear end cover is arranged on the right side of the pump body; the lip-shaped sealing ring penetrates through the left shaft section of the driving gear shaft and is installed on the left side of the front end cover; the pump outlet is arranged in the center of the upper side surface and the lower side surface of the pump body; the positioning pin holes are positioned at the connecting parts of the front end cover and the rear end cover and the pump body respectively; the fixing bolt hole penetrates through the front end cover, the pump body and the rear end cover and is fixed by a nut.

As a preferred technical scheme of the invention, the front contact surface of the front 8-shaped sleeve is the contact surface with the gear section, and the rear contact surface is the contact surface with the pump body; the front 8-shaped sleeve is provided with a through hole and a blind hole, the driving gear shaft is arranged in the through hole, and the driven gear shaft is arranged in the blind hole; two positioning holes I, two positioning holes II and a sealing groove are arranged on the rear contact surface of the positioning sleeve; the arc surface on the front 8-shaped sleeve is provided with a drainage arc groove I and a drainage arc groove II, and a plane between the arc surfaces is provided with a hole II which is communicated with the positioning hole II; the arc surface of the lower side of the front 8-shaped sleeve is respectively provided with a hole I which is respectively communicated with the through hole and the blind hole; an arc groove I is formed beside the through hole on the front contact surface, and an opening is formed in the front contact surface and communicated with the drainage arc groove II; an arc groove II is formed beside the blind hole on the front contact surface, and an opening is formed in the front contact surface and communicated with the drainage arc groove I; an arc groove III is formed in the inner wall of the blind hole, close to the front contact surface, and an opening is formed in the inner wall of the blind hole and communicated with the drainage arc groove II; an arc groove IV is formed in the inner wall of the through hole close to the front contact surface, and the inner opening of the through hole is communicated with the drainage arc groove I.

As a preferred technical scheme of the invention, the angle of the circular arc groove I is 40 degrees, the angle of the circular arc groove II is 80 degrees, and the outer diameters of the two circular arc grooves are smaller than the root circle radiuses of the gear sections of the driving gear shaft and the driven gear shaft; the angle of the arc groove III is 60 degrees, and the angle of the arc groove IV is 90 degrees.

As a preferred technical scheme of the invention, the rear 8-shaped sleeve is different from the front 8-shaped sleeve in that a sealing groove II is formed in the center of a sealing groove I on a rear contact surface, the sealing groove II is a gourd-shaped groove, two holes are blind holes, the angle of an arc groove I is 80 degrees, the angle of the arc groove II is 40 degrees, the angle of an arc groove III is 90 degrees, and the angle of an arc groove IV is 60 degrees.

As a preferable technical scheme of the invention, the front 8-shaped sleeve and the rear 8-shaped sleeve are respectively arranged at the left side and the right side of the driving gear shaft and the driven gear shaft, and the front 8-shaped sleeve and the rear 8-shaped sleeve are symmetrically arranged at the left side and the right side.

Compared with the prior art, the invention has the beneficial effects that:

1. dynamic compensation of radial force of the bearing is carried out, an oil film is formed between the rotating shafts, eccentricity of the two meshed shafts is avoided, abrasion between the bearing and the shafts during rotation is avoided, and a dynamic pressure floating state of the rotating shafts is realized;

2. the axial force generated when the spiral gear is rotationally meshed with a conveying medium is compensated, and the problem that the gear is axially moved under the action of the axial force is solved;

3. the inclination caused by high and low pressure difference of the contact end surface of the gear is effectively relieved;

4. an open loop from high pressure to medium pressure and then to low pressure is formed, dynamic high-pressure oil is introduced to keep constant dynamic pressure, high-temperature oil is taken away to reduce the internal temperature of the hydraulic gear pump, and the functions of lubrication and cooling are achieved. The problem of above can effectively accomplish to reduce revealing, wearing and tearing and the noise of hydraulic gear pump, and then promoted hydraulic gear pump's wholeness ability, also prolonged working life.

Drawings

FIG. 1 is a perspective view of the present invention;

FIG. 2 is a cross-sectional view of the present invention;

FIG. 3 is a schematic perspective view of a front 8-shaped jacket according to the present invention;

FIG. 4 is a schematic perspective view II of the front 8-shaped sleeve of the present invention;

FIG. 5 is a schematic perspective view of a front 8-shaped sleeve according to the present invention;

FIG. 6 is a schematic perspective view I of the rear 8-shaped jacket of the present invention;

in the figure: the pump comprises a driving gear shaft 1, a lip-shaped sealing ring 2, a front end cover 3, a front 8-shaped sleeve 4, a positioning hole I401, a positioning hole II402, a sealing groove I403, a hole I404, a hole II405, a drainage arc groove I406, a drainage arc groove II407, an arc groove I408, an arc groove II409, an arc groove III410, an arc groove IV411, a pump body 5, a rear 8-shaped sleeve 6, a sealing groove II601 rear end cover 7, a driven gear shaft 8, a positioning pin hole 9, a pump outlet 10 and a fixing bolt hole 11.

Detailed Description

Example 1

As shown in fig. 1 to 6, the invention discloses a hydraulic gear pump, which comprises a driving gear shaft 1, a lip-shaped sealing ring 2, a front end cover 3, a front 8-shaped sleeve 4, a pump body 5, a rear 8-shaped sleeve 6, a rear end cover 7, a driven gear shaft 8, a positioning pin hole 9, a pump outlet 10 and a fixing bolt hole 11; the side surfaces of the front end cover 3, the rear end cover 7 and the pump body 5, which are in contact with each other, are provided with through 8-shaped through grooves, and sealing O-shaped rings are arranged in the through grooves; the front end cover 3 is arranged on the left side of the pump body 5; the front 8-shaped sleeve 4 is arranged on the left side inside the pump body 5; the driving gear shaft 1 penetrates through the front end cover 3 and the front 8-shaped sleeve 4 and is arranged in the pump body 1, and the left side surface of a gear section of the driving gear shaft is contacted with the right side surface of the front 8-shaped sleeve 4; the rear 8-shaped sleeve 6 is in contact with the right side of the gear section of the driving gear shaft 1 and is positioned on the right side in the pump body 5; the driven gear shaft 8 penetrates through the front 8-shaped sleeve 4 and the rear 8-shaped sleeve 6 and is arranged in the pump body 5, and the gear section of the driven gear shaft is meshed with the gear section of the driving gear shaft 1; the rear end cover 7 is arranged on the right side of the pump body 5; the lip-shaped sealing ring 2 penetrates through the left shaft section of the driving gear shaft 1 and is installed on the left side of the front end cover 3; the pump outlet 10 is arranged in the center of the upper side surface and the lower side surface of the pump body 5; the positioning pin hole 9 is positioned at the joint of the front end cover 3 and the rear end cover 7 with the pump body 5 respectively; the fixing bolt hole 11 penetrates through the front end cover 3, the pump body and the rear end cover 7 and is fixed by a nut. The front contact surface of the front 8-shaped sleeve 4 is the contact surface with the gear section, and the rear contact surface is the contact surface with the pump body 5; the front 8-shaped sleeve 4 is provided with a through hole and a blind hole, the driving gear shaft 1 is arranged in the through hole, and the driven gear shaft 8 is arranged in the blind hole; the rear contact surface of the positioning structure is provided with two positioning holes I401, two positioning holes II402 and a sealing groove I403; the circular arc surface on the front 8-shaped sleeve 4 is provided with a drainage circular arc groove I406 and a drainage circular arc groove II407, and a plane opening II405 between the circular arc surfaces is communicated with a positioning hole II 402; the arc surface of the lower side of the front 8-shaped sleeve 4 is respectively provided with a hole I404 which is respectively communicated with the through hole and the blind hole; an arc groove I408 is arranged beside the through hole on the front contact surface, and an opening is formed in the front contact surface and communicated with a drainage arc groove II407; an arc groove II409 is arranged beside the blind hole on the front contact surface, and an opening is formed in the front contact surface and communicated with a drainage arc groove I406; an arc groove III410 is formed in the inner wall of the blind hole close to the front contact surface, and an inner opening is communicated with a drainage arc groove II407; an arc groove IV411 is arranged on the inner wall of the through hole close to the front contact surface and communicated with the drainage arc groove I406 through an inner hole. The difference between the rear 8-shaped sleeve 6 and the front 8-shaped sleeve 4 is that a sealing groove II601 is formed in the center of a sealing groove I403 in the rear contact surface, and the sealing groove II601 is a gourd-shaped groove. The front 8-shaped sleeve 4 and the rear 8-shaped sleeve 6 are respectively arranged on the left side and the right side of the driving gear shaft 1 and the driven gear shaft 8, and the front 8-shaped sleeve 4 and the rear 8-shaped sleeve 6 are arranged in a left-right symmetrical mode. Two sets of front and rear 8-shaped sleeves which are symmetrically arranged replace a common bearing to support and fix the driving gear shaft and the driven gear shaft, and liquid in a high-pressure area is led into a space between an inner arc groove of the 8-shaped sleeve and the gear shaft from a side groove and a small hole to form a high-pressure oil film, so that the lubrication and the compensation of radial force are increased, and the abrasion with the gear shaft is reduced. The angle of the arc groove I408 is 40 degrees, the angle of the arc groove II409 is 80 degrees, and the outer diameters of the two arc grooves are smaller than the root circle radius of the gear sections of the driving gear shaft 1 and the driven gear shaft 8; the angle of the arc groove III410 is 60 degrees, and the angle of the arc groove IV411 is 90 degrees. An open loop is formed from high pressure to medium pressure and then to low pressure, dynamic high-pressure oil is introduced to keep constant dynamic pressure, high-temperature oil is taken away to reduce the internal temperature of the hydraulic gear pump, and the functions of lubrication and cooling are achieved. The problem of above can effectively accomplish to reduce revealing, wearing and tearing and the noise of hydraulic gear pump, and then promoted hydraulic gear pump's wholeness ability, also prolonged working life.

The working principle of the invention is as follows: when the gear pump is installed, the gear sections of the driving gear shaft 1 and the driven gear shaft 8 are meshed and installed in the pump body 5, the front 8-shaped sleeve 4 and the rear 8-shaped sleeve 6 are installed on two sides of the gear sections and installed in the pump body 5, then the front end cover 3 and the rear end cover 7 are installed on the left side and the right side of the pump body 5 in sequence, the pump body is sealed through bolt fixing, finally the lip-shaped sealing ring 2 is installed at the outlet of the front end cover 3 and the driving gear shaft 1 to seal the driving gear shaft, and the gear pump is installed.

In the front 8-shaped sleeve, high-pressure oil at the rear contact end surface is introduced into an outlet high-pressure oil through a hole II405 and enters a positioning hole II402, and then reaches the rear contact surface through the positioning hole II402 to form a high-pressure oil film. High-pressure oil is introduced through the drainage arc groove II407 and is respectively communicated with the corresponding hole inner surface arc groove III410 and the front contact surface arc groove I408 to provide high-pressure oil, and finally the high-pressure oil enters the oil inlet through the hole I404. High-pressure oil is introduced through the drainage arc groove I406 and is respectively communicated with the arc groove IV411 of the inner surface of the corresponding hole and the arc groove II409 of the front contact surface to provide high-pressure oil, and finally the high-pressure oil enters the oil inlet through the hole I404.

High-pressure oil is introduced from the arc groove of the front contact surface of the 8-shaped sleeve, so that a part of axial force can be offset, and the gear shaft can axially float to reduce the abrasion; high-pressure oil is introduced into the rear contact surface of the 8-shaped sleeve, and the axial force generated by different gear shafts is solved according to the contact area of the high-pressure oil; the outside of the rear contact surface of the front 8-shaped sleeve and the rear 8-shaped sleeve is sealed to effectively isolate oil in different pressure ranges, so that leakage is reduced; the rear 8-shaped sleeve rear contact surface inner side sealing groove prevents high-pressure oil from leaking, simultaneously enables rear contact surfaces of the two blind holes to generate high-pressure oil contact surfaces with different sizes, the area of the rear contact surface of the rear 8-shaped sleeve corresponding to the driving gear shaft 1 is larger than the area of the rear contact surface of the rear 8-shaped sleeve corresponding to the driven gear shaft 8, and the rear contact surface is used for compensating the axial force applied to the driving gear shaft 1; through form dynamic pressure suspension from hole and groove on "8" jacket, effectively solved the balanced problem of gear shaft radial force and axial force, reduce the wearing and tearing to "8" jacket, make hydraulic gear pump overall noise reduce, can adapt to higher rotational speed, improved the holistic life-span of gear pump.

High-pressure oil is mainly introduced into the rear end face of the front 8-shaped sleeve 4 to compensate axial force, the axial force of the driving gear shaft 1 is just opposite to that of the driven gear shaft 8, the driving gear shaft is matched with a through hole of the front 8-shaped sleeve, if the axial force is directed to the front 8-shaped sleeve, the axial force is not easily compensated, the rotating direction of the driving gear shaft 1 is determined, the axial force applied to the driven gear shaft 8 is directed to the front 8-shaped sleeve, the driving gear shaft 1 is directed to the rear 8-shaped sleeve, in order to effectively compensate the axial force, high-pressure oil is introduced into the rear end face through a hole II405 and a positioning hole II402, the area of a rear contact surface of a blind hole is larger than that of the through hole, and a formed high-pressure area can compensate the axial force applied to the driven gear shaft 8; in order to avoid the contact abrasion between the front contact surface of the front 8-shaped sleeve and the end surface of the gear shaft when the axial force is compensated, the arc groove I408 and the arc groove II409 of the front contact surface are respectively communicated with the side drainage arc groove I406 and the drainage arc groove II407, the drainage arc groove I406 is connected with a high-pressure area, and a high-pressure oil contact surface is introduced to form a high-pressure floating space; because the axial force of the driving gear shaft 1 points to the rear 8-shaped sleeve 6, the axial force received by the driven gear shaft 8 points to the front 8-shaped sleeve 4, and the two contact surfaces are stressed differently, the angle of the arc groove II409 on the contact surface of the driven gear shaft 8 is 80 degrees, the angle of the arc groove I408 on the contact surface of the driving gear shaft is 40 degrees, and the outer diameters of the two arc grooves are smaller than the radius of the gear root circle to avoid communication leakage; the inner surface of a through hole for connecting the front 8-shaped sleeve 4 with the driving gear shaft 1 is provided with an arc groove III410 which is communicated with a drainage arc groove II407; an arc groove IV411 is formed in the inner surface of the blind hole connected with the driven gear shaft and communicated with a drainage arc groove I406; high-pressure oil is introduced to form an oil film with a connected shaft section, so that a rotating shaft floats to avoid contact mechanical abrasion, the radial force borne by a gear shaft is compensated by static pressure formed by a groove, the radial force borne by a driven gear shaft is larger than that of a driving gear shaft, the angle of the arc groove IV411 is 60 degrees, the angle of the arc groove III410 is 90 degrees, the two arc grooves are positioned close to the inner surface of one side of an oil outlet, oil in the shaft hole is compensated and lubricated by force, the pressure is reduced, the temperature is increased, a low-pressure area is introduced through the hole I404 to form an open-loop oil circuit, the open-loop oil circuit is formed, the introduced dynamic high-pressure oil keeps constant dynamic pressure, and the high-temperature oil is taken away to reduce the internal temperature of the hydraulic gear pump. The rear "8" jacket 6 has the same principle as the front "8" jacket 4 and will not be described in detail.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate orientations or positional relationships based on those shown in the drawings, and are used merely for convenience in describing and simplifying the description, but do not indicate or imply that the device or element so referred to must have a particular orientation, be constructed and operate in a particular orientation, and thus are not to be construed as limiting the invention, and further, the terms "first", "second", etc., are used for descriptive purposes only and are not intended to indicate or imply relative importance or to implicitly indicate the number of technical features so indicated, whereby the features defined as "first", "second", etc., may explicitly or implicitly include one or more such features, and unless otherwise indicated, the meaning of "plurality" is two or more than two in the description of the present invention.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements, and the specific meaning of the above terms in the present invention can be understood by those skilled in the art through specific situations

Although the present invention has been described in detail with reference to the specific embodiments, the present invention is not limited to the above embodiments, and various changes and modifications without inventive changes may be made within the knowledge of those skilled in the art without departing from the spirit of the present invention.

Claims

1. A hydraulic gear pump, its characterized in that: the pump comprises a driving gear shaft (1), a lip-shaped sealing ring (2), a front end cover (3), a front 8-shaped sleeve (4), a pump body (5), a rear 8-shaped sleeve (6), a rear end cover (7), a driven gear shaft (8), a positioning pin hole (9), a pump outlet (10) and a fixing bolt hole (11); the side surfaces of the front end cover (3) and the rear end cover (7) which are in contact with the pump body (5) are provided with through 8-shaped through grooves, and sealing O-shaped rings are arranged in the through grooves; the front end cover (3) is arranged on the left side of the pump body (5); the front 8-shaped sleeve (4) is arranged on the left side inside the pump body (5); the driving gear shaft (1) penetrates through the front end cover (3) and the front 8-shaped sleeve (4) and is installed in the pump body (1), and the left side surface of a gear section of the driving gear shaft is in contact with the right side surface of the front 8-shaped sleeve (4); the rear 8-shaped sleeve (6) is in contact with the right side of the gear section of the driving gear shaft (1) and is positioned on the right side inside the pump body (5); the driven gear shaft (8) penetrates through the front 8-shaped sleeve (4) and the rear 8-shaped sleeve (6) and is arranged in the pump body (5), and the gear section of the driven gear shaft is meshed with the gear section of the driving gear shaft (1); the rear end cover (7) is arranged on the right side of the pump body (5); the lip-shaped sealing ring (2) penetrates through the left shaft section of the driving gear shaft (1) and is installed on the left side of the front end cover (3); the pump outlet (10) is arranged in the center of the upper side surface and the lower side surface of the pump body (5); the positioning pin hole (9) is positioned at the joint of the front end cover (3) and the rear end cover (7) and the pump body (5) respectively; the fixing bolt hole (11) penetrates through the front end cover (3), the pump body and the rear end cover (7) and is fixed by a nut.

2. A hydraulic gear pump according to claim 1, characterized in that: the front contact surface of the front 8-shaped sleeve (4) is the contact surface with the gear section, and the rear contact surface is the contact surface with the pump body (5); a through hole and a blind hole are formed in the front 8-shaped sleeve (4), a driving gear shaft (1) is installed in the through hole, and a driven gear shaft (8) is installed in the blind hole; the rear contact surface is provided with two positioning holes I (401), two positioning holes II (402) and a sealing groove I (403); the arc surface on the upper side of the front 8-shaped sleeve (4) is provided with a drainage arc groove I (406) and a drainage arc groove II (407), and a plane opening II (405) between the arc surfaces is communicated with a positioning hole II (402); the arc surface of the lower side of the front 8-shaped sleeve (4) is respectively provided with a hole I (404) which is respectively communicated with the through hole and the blind hole; an arc groove I (408) is formed beside the through hole on the front contact surface, and an opening is formed in the front contact surface and communicated with a drainage arc groove II (407); an arc groove II (409) is formed beside the blind hole on the front contact surface, and an inner opening is communicated with the drainage arc groove I (406); an arc groove III (410) is formed in the inner wall of the blind hole close to the front contact surface, and an opening is formed in the inner wall of the blind hole and communicated with a drainage arc groove II (407); an arc groove IV (411) is formed in the inner wall of the through hole close to the front contact surface, and the inner opening is communicated with the drainage arc groove I (406).

3. A hydraulic gear pump according to claim 2, characterized in that: the angle of the arc groove I (408) is 40 degrees, the angle of the arc groove II (409) is 80 degrees, and the outer diameters of the two arc grooves are smaller than the root circle radiuses of the gear sections of the driving gear shaft (1) and the driven gear shaft (8); the angle of the arc groove III (410) is 60 degrees, and the angle of the arc groove IV (411) is 90 degrees.

4. A hydraulic gear pump according to claim 3, characterized in that: the difference between the rear 8-shaped sleeve (6) and the front 8-shaped sleeve (4) is that a sealing groove II (601) is formed in the center of a sealing groove I (403) on the rear contact surface, the sealing groove II (601) is a gourd-shaped groove, two holes are blind holes, the angle of the arc groove I (408) is 80 degrees, the angle of the arc groove II (409) is 40 degrees, the angle of the arc groove III (410) is 90 degrees, and the angle of the arc groove IV (411) is 60 degrees.

5. A hydraulic gear pump according to claim 4, characterized in that: the front 8-shaped sleeve (4) and the rear 8-shaped sleeve (6) are respectively arranged on the left side and the right side of the driving gear shaft (1) and the driven gear shaft (8), and the front 8-shaped sleeve (4) and the rear 8-shaped sleeve (6) are symmetrically arranged on the left side and the right side.