Bidirectional gear pump

Abstract

The bidirectional gear pump comprises a front shell, a rear shell, a first shaft hole, a second shaft hole, a third shaft hole, a fourth shaft hole, a first gear shaft and a second gear shaft, wherein the first shaft hole, the second shaft hole, the third shaft hole and the fourth shaft hole are vertically and symmetrically formed in the horizontal center line of the front shell and the rear shell; a first groove and a second groove are formed around the first shaft hole and the second shaft hole, the first gear and the second gear are installed in the grooves, and the first gear and the second gear are connected in a meshed mode; oil drainage grooves are formed in the outer end surfaces; the thicknesses of the first gear and the second gear are consistent with the depths of the first groove and the second groove of the front shell; an oil inlet and an oil outlet are formed in the outer end face of the rear shell and located in the two sides of the vertical center line of the rear shell. No gap exists between the inner end face of the front shell and the inner end face of the rear shell.

Description

Technical Field

[0001] The invention relates to the technical field of hydraulic pumps, and in particular to a bidirectional gear pump. Background Art

[0002] Chinese patent publication CN216894885U discloses a self-lubricating bidirectional gear pump, which includes a pump body, a first end cover arranged at one end of the pump body, and a second end cover arranged at the other end of the pump body. The pump body is provided with a first gear, a second gear meshingly connected with the first gear, and a first floating block and a second floating block with a first gear shaft hole and a second gear shaft hole and an "8" shape and respectively fitted on both sides of the first gear and the second gear. The first end cover is provided with a first check valve, a second check valve, a first rubber sealing pad and a first nylon pad, and the second end cover is provided with an oil seal, a shaft sleeve, a hole elastic retaining ring, a mold ring, a second rubber sealing pad and a second nylon pad. The utility model can solve the wear and power consumption caused by the mutual movement between the first gear, the second gear and the floating block, and improve the lubrication effect in the bidirectional gear pump.

[0003] Chinese patent publication CN 117329345A discloses an integrated electro-hydraulic actuator, which relates to the field of electro-hydraulic execution control technology. It includes a housing, an electric control device, a hydraulic device and a motion device. The motion device is connected to a valve stem. The electric control device includes a gear pump for providing hydraulic oil to the hydraulic device. The hydraulic device is used to provide hydraulic pressure to drive the motion device to drive the valve stem to rotate. It also includes a pipe valve device, a magnetic control device and a clutch device. The pipe valve device is used to switch the hydraulic pipeline or the return oil pipeline to connect with the gear pump. The magnetic control device is connected to the gear pump. The clutch device includes a dial assembly and a disconnect assembly. The magnetic control device is used to control the dial assembly to transmit a rotational force to control the pipe valve device to switch the return oil pipeline and the hydraulic pipeline. The dial assembly is also used to control the disconnect assembly to separate from the motion device and transmit the rotational force through the disconnect assembly to control the rotation of the valve stem. It has a dual-mode switching control with integrated electric and electro-hydraulic control modes to improve valve control efficiency and safety.

[0004] Compared with other types of hydraulic pumps, gear pumps are widely used in electro-hydraulic actuators due to their simple structure and small size. Due to the small size of integrated electro-hydraulic actuators, gear pumps are required to have small displacement, high rated working pressure, and high volumetric efficiency. Traditional small-displacement bidirectional gear pumps are generally composed of a second gear, a bearing sleeve floating sleeve, a sealing ring, a front cover, a floating side plate with a compensating sealing ring, a transmission shaft, a first gear, a housing, and a rear cover. Traditional gear pumps are generally used as power components. This type of gear pump has a large gear module, a small number of teeth, low precision, and large flow and pressure pulsations. In order to improve the volumetric efficiency, compensation methods such as adding a floating side plate with a compensating seal ring to the gear end face are used to reduce the leakage of the gear end face. This is a floating gap. In this way, the volumetric efficiency of the gear pump becomes smaller when working at low pressure, and the driving torque of the gear pump increases when working at high pressure, which greatly reduces the response speed of the pump. It is not suitable for frequent start and stop working conditions, does not meet the response speed requirements of the electro-hydraulic actuator, and is not suitable for use as a control element. Moreover, this gear pump with small displacement and high volumetric efficiency is difficult to achieve, and does not meet the requirements of the integrated electro-hydraulic actuator for pump response time and control accuracy. Summary of the invention

[0005] In order to solve the above technical problems, the first aspect of the present invention provides a high-precision high-pressure bidirectional gear pump, the bidirectional gear pump is installed in the oil tank; The bidirectional gear pump comprises: a front housing, a rear housing, a first gear and a second gear, a first gear shaft and a second gear shaft; a first shaft hole and a second shaft hole are symmetrically arranged on the horizontal center line of the front housing; a third shaft hole and a fourth shaft hole are symmetrically arranged on the horizontal center line of the rear housing; the first gear shaft is directly rotatably installed in the first shaft hole and the third shaft hole, and the second gear shaft is directly rotatably installed in the second shaft hole and the fourth shaft hole; A first groove and a second groove are arranged on the inner end surface of the front housing around the first shaft hole and the second shaft hole, the first gear is installed in the first groove, the second gear is installed in the second groove, and the first gear and the second gear are meshed and connected; An oil drain groove is provided on the outer end surface of the front housing; The thickness of the first gear and the second gear is consistent with the depth of the first groove and the second groove of the front housing; An oil inlet and an oil outlet are arranged on the outer end surface of the rear housing, and the oil inlet and the oil outlet are located on both sides of the vertical center line of the rear housing; The inner end surface of the front shell (1) abuts against the inner end surface of the rear shell (5), and the gap between the inner end surface of the front shell (1) and the inner end surface of the rear shell (5) is less than or equal to 3 microns.

[0006] In the bidirectional gear pump of the first aspect of the present invention, a first gear shaft cylindrical pin key hole is provided on the first gear shaft; one end of the first gear shaft is in a stepped shape, and the stepped end extends out of the bidirectional gear pump housing; The second gear shaft is provided with a second gear shaft cylindrical pin key hole for installing the second gear shaft cylindrical pin key.

[0007] As in the bidirectional gear pump of the first aspect of the present invention, the first gear and the second gear are both hollow structures, and the inner annular surface of the hollow structure is provided with an arc-shaped keyway; The first gear shaft passes through the hollow structure of the first gear, and the first gear shaft is connected to the first gear through a cylindrical pin key of the first gear shaft; The second gear shaft passes through the hollow structure of the second gear, and the second gear shaft is connected to the second gear through a cylindrical pin key of the second gear shaft; As in the bidirectional gear pump of the first aspect of the present invention, the front housing further comprises: a first fixing threaded hole, a second fixing threaded hole, a first fixing hole, a second fixing hole, a first oil drain hole and a second oil drain hole; A first load relief groove and a second load relief groove are arranged on the inner end surface of the front shell; The center lines of the first unloading groove and the second unloading groove coincide with the horizontal center line of the front shell body, and are symmetrically arranged on both sides of the vertical center line of the front shell body. The first unloading groove and the second unloading groove are elliptical in shape.

[0008] As in the bidirectional gear pump of the first aspect of the present invention, the front housing further comprises an oil drain groove; The oil drain groove is in a T-shape with a long section and a short section intersecting each other, one end of the T-shaped long section is connected to an oil drain hole, and the T-shaped short section is connected to the coaxial hole.

[0009] As in the bidirectional gear pump of the first aspect of the present invention, on the front housing, the first fixed threaded hole, the first fixed hole, the second fixed threaded hole, and the second fixed hole are arranged alternately in sequence and are symmetrically distributed around the center of the front housing; the first oil drain hole and the second oil drain hole are located between the fixed threaded hole and the fixed hole, and the first oil drain hole and the second oil drain hole are symmetrically distributed around the center of the front housing.

[0010] As in the bidirectional gear pump of the first aspect of the present invention, the rear housing further comprises: a third fixing threaded hole, a fourth fixing threaded hole, a third fixing hole, a fourth fixing hole, a third oil drain hole and a fourth oil drain hole; A third load relief groove and a fourth load relief groove are arranged on the inner end surface of the rear shell; The center lines of the third and fourth load relief grooves coincide with the horizontal center line of the rear shell body, and are symmetrically arranged on both sides of the vertical center line of the rear shell body. The center lines of the third and fourth load relief grooves are elliptical in shape.

[0011] As in the bidirectional gear pump of the first aspect of the present invention, on the rear housing, the third fixing hole, the third fixed threaded hole, the fourth fixing hole, and the fourth fixed threaded hole are arranged alternately in sequence and are symmetrically distributed around the center of the rear housing; the third oil drain hole and the fourth oil drain hole are located between the fixed threaded hole and the fixed hole, and the two oil drain holes are symmetrically distributed around the center of the rear housing.

[0012] As in the bidirectional gear pump of the first aspect of the present invention, the fixing holes of the rear housing are arranged corresponding to the fixing threaded holes of the front housing, and the fixing holes of the front housing are arranged corresponding to the fixing threaded holes of the rear housing; A fixing bolt is passed through the fixing hole and screwed into a corresponding fixing threaded hole to fix the front housing and the rear housing, so that there is no gap between the fixed front housing (1) and the rear housing (5).

[0013] As in the bidirectional gear pump of the first aspect of the present invention, the stepped end of the first gear shaft extends out of the housing of the bidirectional gear pump; the stepped end is connected to the drive motor through a coupling, and the first gear is the driving gear of the bidirectional gear pump.

[0014] The advantages of the present invention compared with the prior art are: The bidirectional gear pump of the present invention adopts a two-piece structure and a fixed gap, has a small number of parts, no bearings, no seals, a simple structure, a small gear module, a large number of teeth, and a hollow gear structure, which can easily improve the flatness of the gear end face and ensure the gear end face gap and radial gap, thereby achieving both low leakage and low resistance. The hydraulic pump has the characteristics of small size, high pressure, small flow and pressure pulsation, high volumetric efficiency, small starting torque, and fast response speed, solving the problem that traditional bidirectional small-displacement gear pumps are large in size, low in volumetric efficiency, large in flow and pressure pulsation, and slow in response speed, and cannot meet the requirements of integrated electro-hydraulic actuators. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is the overall structural diagram of the bidirectional gear pump of the present invention; Figure 2 It is a front view of the bidirectional gear pump of the present invention; Figure 3 This is the appearance of the bidirectional gear pump of the present invention. Figure 2 Left view of; Figure 4 The bidirectional gear pump of the present invention Figure 3 Section view in the AA direction; Figure 5 This is the appearance of the bidirectional gear pump of the present invention. Figure 2 Right view of; Figure 6 is a structural diagram of the first gear shaft of the present invention; Figure 7 is a structural diagram of the second gear shaft of the present invention; Figure 8 It is a structural diagram of the cylindrical pin key of the first gear shaft and the cylindrical pin key of the second gear shaft of the present invention; Fig. 9 is a structural diagram of the front housing of the present invention; Fig.10yes Fig. 9 AA section view; Fig.11 yes Fig.10 Right view of; Fig.12 is a structural diagram of the rear housing of the present invention; Fig.13 yes Fig.12 AA section view; Fig.14 yes Fig.13 Right view of; Fig.15 is a schematic diagram of the first gear structure of the present invention; Fig.16 is a schematic diagram of the second gear structure of the present invention; Fig.17 This is an application example diagram of the bidirectional gear pump of the present invention.

[0016] The reference numerals are as follows: 1, front housing; 11-1, first gear groove; 11-2, second gear groove; 12-1, first shaft hole; 12-2, second shaft hole; 13-1, first fixing threaded hole; 13-2, second fixing threaded hole; 14-1, first load relief groove; 14-2, second load relief groove; 15-1, first oil leakage hole; 15-2, second oil leakage hole; 16-1, first fixing hole; 16-2, second fixing hole; 17, oil leakage groove; 2. First gear; 21. First shaft hole; 22. First gear keyway; 3. First gear shaft; 31. First gear shaft stepped end; 32. First gear shaft cylindrical pin keyhole; 4. First gear shaft cylindrical pin key; 5. rear housing; 51-1. oil inlet; 51-2. oil outlet; 52-1. third gear shaft hole; 52-2. third gear shaft hole; 53-1. third fixing hole; 53-2. fourth fixing hole; 54-1. third load relief groove; 54-2, fourth load relief groove; 55-1, third oil leakage hole; 55-2, fourth oil leakage hole; 56-1, third fixing hole; 56-2, fourth fixing hole; 6, second gear shaft; 6-1, cylindrical pin key hole of second gear shaft; 7. Second gear; 71. Second gear shaft hole; 72. Second gear keyway; 8. Second gear shaft cylindrical pin key; 9-first bolt; 10-second bolt.

[0017] Ⅰ. Driving motor; Ⅱ. Coupling; Ⅲ. Bidirectional gear pump; Ⅳ. Oil inlet pipe; Ⅴ. Oil outlet pipe; Ⅵ. Electro-hydraulic actuator oil tank. DETAILED DESCRIPTION

[0018] The present invention provides a bidirectional gear pump, which adopts a small displacement gear pump with a fixed gap, a two-piece structure and no bearings. The bidirectional gear pump of the present invention can be used in an integrated electro-hydraulic actuator and has forward and reverse rotation functions.

[0019] The technical scheme of the present invention will be clearly and completely described below in conjunction with specific embodiments, but those skilled in the art should understand that the following embodiments are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] The present invention is described in detail below in conjunction with the accompanying drawings. Figure 1 As shown, the overall structure diagram of the bidirectional gear pump of the present invention; A first aspect of the present invention provides a bidirectional gear pump, a bidirectional gear pump mounted in an integrated electro-hydraulic actuator tank; The bidirectional gear pump comprises: a front housing 1, a rear housing 5, a first gear 2 and a second gear 7, a first gear shaft 3 and a second gear shaft 6; a first shaft hole and a second shaft hole are symmetrically arranged on the horizontal center line of the front housing 1; a third shaft hole and a fourth shaft hole are symmetrically arranged on the horizontal center line of the rear housing 5; the first gear shaft 3 is directly rotatably installed in the first shaft hole and the third shaft hole, and the second gear shaft 6 is directly rotatably installed in the second shaft hole and the fourth shaft hole; A first groove 11-1 and a second groove 11-2 are arranged on the inner end surface of the front housing 1 around the first shaft hole 12-1 and the second shaft hole 12-2, the first gear 2 is installed in the first groove 11-1, the second gear 7 is installed in the second groove 11-2, and the first gear 2 and the second gear 7 are meshed and connected; an oil drain groove 17 is arranged on the outer end surface of the front housing 1; the thickness of the first gear 2 and the second gear 7 is consistent with the depth of the first groove 11-1 and the second groove 11-2 of the front housing 1; An oil inlet 51 - 1 and an oil outlet 51 - 2 are provided on the outer end surface of the rear housing 5 , and the oil inlet 51 - 1 and the oil outlet 51 - 2 are located on both sides of the vertical center line of the rear housing 5 ; The inner end surface of the front housing 1 abuts against the inner end surface of the rear housing 5 , and a gap between the inner end surface of the front housing 1 and the inner end surface of the rear housing 5 is less than or equal to 3 microns. Example

[0021] The maximum working pressure of the bidirectional gear pump in this embodiment is 25MPa, the gear has a small modulus, and the gear modulus is less than 2. Fig.17As shown, an application case of the bidirectional gear pump of the present invention, the driving motor I is connected to the bidirectional gear pump III shaft through a coupling II, the bidirectional gear pump is installed in the actuator oil tank VI, the oil inlet pipe IV and the oil outlet pipe V are connected to the oil inlet and outlet of the bidirectional gear pump III, the motor drives the bidirectional gear pump to rotate clockwise or counterclockwise, and the pressure oil is output from the oil inlet pipe IV and the oil outlet pipe V.

[0022] As in the bidirectional gear pump of the first aspect of the present invention, a first gear shaft cylindrical pin key hole 32 is provided on the first gear shaft 3; one end of the first gear shaft 3 is a stepped shape 31, and the end of the stepped shape 31 extends out of the bidirectional gear pump housing; The second gear shaft 6 is provided with a second gear shaft cylindrical pin key hole 6 - 1 for installing the second gear shaft cylindrical pin key 8 .

[0023] As in the bidirectional gear pump of the first aspect of the present invention, the first gear 2 and the second gear 7 are both hollow structures, and the inner annular surface of the hollow structure is provided with an arc-shaped keyway; The first gear shaft 3 passes through the hollow structure of the first gear 2, and the first gear shaft 3 is connected to the first gear 2 via a first cylindrical pin key 4; The second gear shaft 6 passes through the hollow structure of the second gear 7 and is connected by the second gear shaft cylindrical pin key 8; Example

[0024] As attached Figure 2-8 The structural diagram of the components of the bidirectional gear pump is shown.

[0025] The high-pressure bidirectional gear pump of the present invention comprises: a first gear 2 and a second gear 7 with a module of 0.5 and a number of teeth of 34; a first gear keyway 22 and a second gear keyway 72 are both arc-shaped, and contain a first gear shaft hole 21 and a second gear shaft hole 71 therein.

[0026] The thickness of the gear is consistent with the depth of the groove of the front housing.

[0027] The first gear shaft is provided with a first gear shaft cylindrical pin key hole 32 and a stepped shape 31 connected to the prime mover.

[0028] The above-mentioned second gear shaft is provided with a second gear shaft cylindrical pin key hole 6-1.

[0029] One end of the cylindrical pin key hole is hemispherical and the other end is flat, and the hemispherical end is connected with the arc keyway of the gear.

[0030] As in the bidirectional gear pump of the first aspect of the present invention, the front housing further comprises: a first fixing threaded hole 13-1, a second fixing threaded hole 13-2, a first fixing hole 16-1, a second fixing hole 16-2, a first oil drain hole 15-1 and a second oil drain hole 15-2; A first load relief groove 14-1 and a second load relief groove 14-2 are provided on the inner end surface of the front housing; The center lines of the first unloading groove 14-1 and the second unloading groove 14-2 coincide with the horizontal center line of the front housing 1, and are symmetrically arranged on both sides of the vertical center line of the front housing 1. The first unloading groove 14-1 and the second unloading groove 14-2 are elliptical in shape.

[0031] As in the bidirectional gear pump of the first aspect of the present invention, the front housing further comprises an oil drain groove 17; The oil drain groove 17 is in a T-shape with a long section and a short section intersecting each other. One end of the T-shaped long section is connected to an oil drain hole, and the T-shaped short section is connected to the coaxial hole.

[0032] As in the bidirectional gear pump of the first aspect of the present invention, on the front housing, the first fixed threaded hole 13-1, the first fixed hole 16-1, the second fixed threaded hole 13-2, and the second fixed hole 16-2 are arranged alternately in sequence and are symmetrically distributed around the center of the front housing 1; the first oil drain hole 15-1 and the second oil drain hole 15-2 are located between the fixed threaded hole and the fixed hole, and the first oil drain hole 15-1 and the second oil drain hole 15-2 are symmetrically distributed around the center of the front housing 1.

[0033] As in the bidirectional gear pump of the first aspect of the present invention, the rear housing further comprises: a third fixing threaded hole 53-1, a fourth fixing threaded hole 53-2, a third fixing hole 56-1, a fourth fixing hole 56-2, a third oil drain hole 55-1 and a fourth oil drain hole 55-2; A third load relief groove 54-1 and a fourth load relief groove 54-2 are provided on the inner end surface of the rear housing; The center lines of the third unloading groove 54-1 and the fourth unloading groove 54-2 coincide with the horizontal center line of the rear housing 1 and are symmetrically arranged on both sides of the vertical center line of the rear housing 1. The center lines of the third unloading groove 54-1 and the fourth unloading groove 54-2 are elliptical in shape.

[0034] As in the bidirectional gear pump of the first aspect of the present invention, on the rear housing, the third fixing hole 56-1, the third fixing threaded hole 53-1, the fourth fixing hole 56-2, and the fourth fixing threaded hole 53-2 are arranged alternately in sequence and are symmetrically distributed around the center of the rear housing 1; the third oil drain hole 55-1 and the fourth oil drain hole 55-2 are located between the fixing threaded hole and the fixing hole, and the two oil drain holes are symmetrically distributed around the center of the rear housing 1.

[0035] As in the bidirectional gear pump of the first aspect of the present invention, the fixing holes of the rear housing are arranged corresponding to the fixing threaded holes of the front housing, and the fixing holes of the front housing are arranged corresponding to the fixing threaded holes of the rear housing; A fixing bolt is passed through the fixing hole and screwed into the corresponding fixing threaded hole to fix the front housing 1 and the rear housing 5. After the fixing is completed, the gap between the front housing (1) and the rear housing (5) is less than or equal to 3 microns.

[0036] As in the bidirectional gear pump of the first aspect of the present invention, the stepped end 31 of the first gear shaft 3 extends out of the housing of the bidirectional gear pump; the stepped end 31 is connected to the drive motor through a coupling, and the first gear 2 is the driving gear of the bidirectional gear pump. Example

[0037] As attached Figure 9-16As shown, the bidirectional gear pump of the present invention comprises: a front housing 1, a first gear 2, a first gear shaft 3, a first gear shaft cylindrical pin key 4, a rear housing 5, a second gear shaft cylindrical pin key 6, a second gear shaft 7, and a second gear 8. The first gear 2 and the second gear 8 have the same structure and technical parameters, both with a module of 0.5 and a number of teeth of 34. They are respectively placed in the first gear groove 11-1 and the second gear groove 11-2 in the front housing 1. The first gear shaft 3 passes through the first gear shaft hole 21 and the first gear shaft hole 12-1 of the front housing 1 from the stepped portion. The first gear shaft cylindrical pin key 4 is installed in the cylindrical pin key hole 32 of the first gear shaft 3. The first gear shaft cylindrical pin key 4 in the first gear shaft 3 enters the first gear keyway 22 of the first gear 2; the second gear shaft 7 passes through the second gear 8 and the second gear shaft hole 12-2 of the front housing, and the second gear shaft cylindrical pin key 6 in the second gear shaft 2 enters the keyway of the second gear 8. The third gear shaft hole 52-1 and the fourth gear shaft hole 52-2 in the rear housing 5 are respectively installed in the tails of the first gear shaft and the second gear shaft, and are connected and fixed together with the first fixing threaded hole 13-1 and the second fixing threaded hole 13-2 of the front housing 1 by the first bolt 9 and the second bolt 10 through the fixing hole in the rear housing 5. There are oil inlet 51-1 and oil outlet 51-2 in the rear housing 5. The prime mover is connected to the step type 31 at one end of the first gear shaft 3 extending out of the housing through a coupling, driving the gear pump to rotate counterclockwise or clockwise, with a maximum speed of 3600rpm, and outputting pressure oil from the oil inlet 51-1 and the oil outlet 51-2. The front housing 1 has a front housing oil drain groove 17 connected to the oil drain hole 15 on the end surface; the first oil drain hole 15-1 and the second oil drain hole 15-2 of the front housing are respectively connected to the third oil drain hole 55-1 and the fourth oil drain hole 55-2 of the rear housing 5, and the leakage oil of the gear pump flows from the first oil drain hole 15-1 and the second oil drain hole 15-2, the third oil drain hole 55-1, and the fourth oil drain hole 55-2 to the hydraulic system oil tank. The first fixing hole 16-1-, the second fixing hole 16-2 of the front housing and the third fixing hole 56-1, the fourth fixing hole 56-2 in the rear housing are used to connect the gear pump with other hydraulic devices; the first gear shaft 3 and the second gear shaft 7 are directly assembled in the first gear shaft hole 12-1, the second gear shaft hole 12-2 and the third gear shaft hole 52-1, the fourth gear shaft hole 52-2 of the rear housing 5, and there is no sliding bearing between the gear shaft and the shaft hole, but the self-lubricating function of the housing material is relied on; there is no rubber seal between the front housing 1 and the rear housing, and the leakage of the gear pump is controlled by controlling the gap between the two. The gap between the front housing 1 and the rear housing can be between 1-3 microns, with a typical value of 2 microns. The friction between the gear and the housing is consistent when the gear pump is working at high pressure and low pressure. The inner end surface of the front housing has the first relief groove 14-1 of the front housing and the second relief groove 14-2 of the front housing, and the inner end surface of the rear housing has the third relief groove 54-1 and the fourth relief groove 54-2, which are used to solve the problem of oil trapped in the gear pump.

[0038] Although the present invention has been described in detail above by general description and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. A bidirectional gear pump, characterized in that: The bidirectional gear pump is installed in an oil tank; the bidirectional gear pump comprises: a front housing (1), a rear housing (5), a first gear (2) and a second gear (7), a first gear shaft (3) and a second gear shaft (6); a first shaft hole and a second shaft hole are symmetrically arranged above and below the horizontal center line of the front housing (1); a third shaft hole and a fourth shaft hole are symmetrically arranged above and below the horizontal center line of the rear housing (5); the first gear shaft (3) is directly rotatably installed in the first shaft hole and the third shaft hole, and the second gear shaft (6) is directly rotatably installed in the second shaft hole and the fourth shaft hole; a first groove (11-1) and a second groove (11-2) are arranged on the inner end surface of the front housing (1) around the first shaft hole (12-1) and the second shaft hole (12-2); the first gear (2) is installed in the first shaft hole (12-1) and the second shaft hole (12-2); the first gear (2) is installed in the first shaft hole (12-1) and the second shaft hole (12-2); the first gear (2) is installed in the first shaft hole (12-1) and the second shaft hole (12-2); the first gear (2) is installed in the second shaft hole (12-2); the second gear (6) is installed in the second shaft hole (12-2); the first gear (2) is installed in the first shaft hole (12-1) and ... A second gear (7) is installed in a groove (11-1), and the second gear (7) is installed in the second groove (11-2), and the first gear (2) and the second gear (7) are meshed and connected; an oil drain groove (17) is provided on the outer end surface of the front housing (1); the thickness of the first gear (2) and the second gear (7) is consistent with the depth of the first groove (11-1) and the second groove (11-2) of the front housing (1); an oil inlet (51-1) and an oil outlet (51-2) are provided on the outer end surface of the rear housing (5), and the oil inlet (51-1) and the oil outlet (51-2) are located on both sides of the vertical center line of the rear housing (5); the inner end surface of the front housing (1) is abutted against the inner end surface of the rear housing (5), and the gap between the inner end surface of the front housing (1) and the inner end surface of the rear housing (5) is less than or equal to 3 microns.

2. The bidirectional gear pump according to claim 1, characterized in that: The first gear shaft (3) is provided with a first gear shaft cylindrical pin key hole (32); one end of the first gear shaft (3) is in a stepped shape (31), and the end of the stepped shape (31) extends out of the housing of the bidirectional gear pump; and the second gear shaft (6) is provided with a second gear shaft cylindrical pin key hole (6-1) for mounting a second gear shaft cylindrical pin key (8).

3. The bidirectional gear pump according to claim 2, characterized in that: The first gear (2) and the second gear (7) are both hollow structures, and the inner ring surface of the hollow structure is provided with an arc-shaped keyway; The first gear shaft (3) passes through the hollow structure of the first gear (2), and the first gear shaft (3) and the first gear (2) are connected via a first gear shaft cylindrical pin key (4); The second gear shaft (6) passes through the hollow structure of the second gear (7), and the second gear shaft (6) and the second gear (7) are connected via a second gear shaft cylindrical pin key (8).

4. The bidirectional gear pump according to claim 1, characterized in that: The front housing further comprises: a first fixing threaded hole (13-1), a second fixing threaded hole (13-2), a first fixing hole (16-1), a second fixing hole (16-2), a first oil drain hole (15-1) and a second oil drain hole (15-2); A first load relief groove (14-1) and a second load relief groove (14-2) are arranged on the inner end surface of the front shell; The center lines of the first load relief groove (14-1) and the second load relief groove (14-2) coincide with the horizontal center line of the front shell (1), and are symmetrically arranged on both sides of the vertical center line of the front shell (1). The first load relief groove (14-1) and the second load relief groove (14-2) are elliptical in shape.

5. The bidirectional gear pump according to claim 4, characterized in that: The front housing further comprises an oil drain groove (17); the oil drain groove (17) is in the shape of a T with a long section and a short section intersecting each other, one end of the long T section is connected to one of the first oil drain hole (15-1) and the second oil drain hole (15-2), and the short T section is connected to one of the first shaft hole and the second shaft hole.

6. The bidirectional gear pump according to claim 4, characterized in that: On the front housing, the first fixing threaded hole (13-1), the first fixing hole (16-1), the second fixing threaded hole (13-2), and the second fixing hole (16-2) are arranged alternately in sequence and are symmetrically distributed around the center of the front housing (1); the first oil leakage hole (15-1) and the second oil leakage hole (15-2) are located between the fixing threaded hole and the fixing hole, and the first oil leakage hole (15-1) and the second oil leakage hole (15-2) are symmetrically distributed around the center of the front housing (1).

7. The bidirectional gear pump according to claim 6, characterized in that: The rear housing further comprises: a third fixing threaded hole (53-1), a fourth fixing threaded hole (53-2), a third fixing hole (56-1), a fourth fixing hole (56-2), a third oil drain hole (55-1) and a fourth oil drain hole (55-2); a third load relief groove (54-1) and a fourth load relief groove (54-2) are arranged on the inner end surface of the rear housing; the center lines of the third load relief groove (54-1) and the fourth load relief groove (54-2) coincide with the horizontal center line of the rear housing (1), and are symmetrically arranged on both sides of the vertical center line of the rear housing (1); the shape of the center lines of the third load relief groove (54-1) and the fourth load relief groove (54-2) is elliptical.

8. The bidirectional gear pump according to claim 7, characterized in that: On the rear housing, the third fixing hole (56-1), the third fixing threaded hole (53-1), the fourth fixing hole (56-2), and the fourth fixing threaded hole (53-2) are alternately arranged in sequence and are symmetrically distributed around the center of the rear housing (1); the third oil drain hole (55-1) and the fourth oil drain hole (55-2) are located between the fixing threaded hole and the fixing hole, and the two oil drain holes are symmetrically distributed around the center of the rear housing (1).

9. The bidirectional gear pump according to claim 8, characterized in that: The fixing holes of the rear shell are arranged corresponding to the fixing threaded holes of the front shell, and the fixing holes of the front shell are arranged corresponding to the fixing threaded holes of the rear shell; fixing bolts are passed through the fixing holes and screwed into the corresponding fixing threaded holes to fix the front shell (1) and the rear shell (5), and no gap is left between the fixed front shell (1) and the rear shell (5).

10. The bidirectional gear pump according to claim 2, characterized in that: The stepped end (31) of the first gear shaft (3) extends out of the housing of the bidirectional gear pump; the stepped end (31) is connected to a drive motor via a coupling, and the first gear (2) is a driving gear of the bidirectional gear pump.

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