A circular arc gear pump for preventing excessive oil pressure

Abstract

The utility model relates to the technical field of circular arc gear pumps, and discloses a circular arc gear pump that prevents excessive oil pressure, including a pump body, a front cover and a rear cover arranged at the front and rear ends of the pump body, a driving shaft and a driven shaft arranged in the pump body, and driving gears and driven gears meshing with each other are arranged on the driving shaft and the driven shaft, one end of the driving shaft passes through the front cover, and the other end of the driving shaft and both ends of the driven shaft are located in the pump body, a sealing structure is arranged on the side of the driving shaft in the front cover, and a pump seat of an integrated structure is arranged at the bottom of the pump body. The circular arc gear pump that prevents excessive oil pressure has the advantages of preventing oil leakage, automatically returning oil to reduce pressure when the pressure is too high, and convenient disassembly and installation of the safety valve, which solves the problems of oil leakage, excessive pressure in the oil discharge chamber, and inconvenient disassembly and installation of the safety valve.

Description

Technical Field

[0001] The utility model relates to the technical field of circular arc gear pumps, in particular to a circular arc gear pump that prevents excessive oil pressure. Background Art

[0002] The circular arc gear pump is a rotary pump that relies on the change and movement of the working volume formed between the pump cylinder and the meshing gears to transport liquid or increase its pressure. Its working principle is based on the principle of a positive displacement pump. It consists of two gears, a pump body, and two closed spaces formed by front and rear covers. When the gears rotate, the volume of the space on the side where the gears are disengaged changes from small to large, forming a vacuum and sucking the liquid in; the volume of the space on the side where the gears are meshing changes from large to small, squeezing the liquid into the pipeline. The driving gear and the driven gear adopt the structure of "circular arc + involute + herringbone spiral". The bottom and top of the teeth are circular arcs, and the arcs are transitioned by involutes. The teeth are in a herringbone spiral structure on the cylindrical surface.

[0003] For example, the patent document with the announcement number CN103775332B discloses a circular arc gear pump, including a pump housing, a first bearing box, a first bearing end cover, an upper cover, a lower cover, a second bearing box, a driving shaft, a driven shaft, two first gears, two second gears, a driving gear key, a driven gear key, a pump housing end cover, a second bearing end cover and a gasket, etc.; wherein, the first gear and the second gear both adopt a compound circular arc tooth shape combining a double arc plus a sine curve with a herringbone tooth shape. The gear pump of the present invention adopts a herringbone tooth gear to replace the traditional involute gear, which has the advantages of no relative sliding of the tooth profile surface during the gear meshing process, so there is no wear on the tooth surface, stable operation, no liquid phenomenon, low noise, long life, high efficiency, etc.

[0004] However, the existing circular arc gear pumps still have the following problems: 1. The gaps between the pump body and other components are prone to oil leakage, which reduces the pressure resistance and stability of the gear pump; 2. When the oil discharge pressure is too high or a fault occurs in the oil discharge pipeline, that is, when the oil discharge pipe valve is closed, the pressure in the oil discharge chamber exceeds the safety pressure, causing a fault; 3. The safety valve is inconvenient to install. Utility Model Content

[0005] 1. Technical issues to be resolved

[0006] In view of the shortcomings of the prior art, the utility model provides an arc gear pump that prevents excessive oil pressure. It has the advantages of preventing oil leakage, automatically returning oil to reduce pressure when the pressure is too high, and easy disassembly and installation of the safety valve, solving the problems of oil leakage, excessive pressure in the oil discharge chamber, and inconvenient disassembly and installation of the safety valve.

[0007] (II) Technical solution

[0008] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0009] A circular arc gear pump for preventing oil pressure from being too high comprises a pump body, a front cover and a rear cover arranged at the front and rear ends of the pump body, a driving shaft and a driven shaft are arranged in the pump body, and a driving gear and a driven gear meshing with each other are arranged on the driving shaft and the driven shaft, one end of the driving shaft passes through the front cover, and the other end of the driving shaft and both ends of the driven shaft are located in the pump body, a sealing structure is arranged in the front cover at the side position of the driving shaft, and a pump seat of an integrated structure is arranged at the bottom of the pump body;

[0010] The pump body is also provided with a detachable safety valve, and an oil suction chamber and an oil discharge chamber are provided on both sides of the driving gear and the driven gear in the pump body, and the oil suction chamber and the oil discharge chamber are respectively connected to the No. 1 channel and the No. 2 channel, and the other ends of the No. 1 channel and the No. 2 channel are connected to the contact surface between the pump body and the detachable safety valve, and the No. 3 channel and the No. 4 channel connected together are provided in the detachable safety valve, and the No. 4 channel is provided with a valve body, and the valve body is connected with an elastic device, and the detachable safety valve is fixed to the pump body by bolts, and the No. 4 channel is aligned with the No. 2 channel, and the No. 3 channel is aligned with the No. 1 channel, and the valve body is stuck in the No. 4 channel under the action of the elastic device.

[0011] Preferably, the cross section of the No. 2 channel at the contact surface with the No. 4 channel is larger than the cross section of the No. 4 channel at the same position, a bottom valve block is provided at the bottom of the valve body, the side of the bottom valve block is an inclined surface, the inclined side wall of the bottom valve block is on the top of the side wall of the No. 4 channel, a side valve block is also provided on the side of the valve body, the bottom of the side valve block is a plane, and a plurality of auxiliary ejector rod devices uniformly distributed in a circle that slide up and down are also provided in the side wall of the No. 4 channel, and the auxiliary ejector rod device includes:

[0012] A piston ring, one end of which is located in the same space as the No. 2 channel, and the other end of which is fixedly connected to the piston rod, and the side surface of the piston ring is tightly fitted inside the side wall of the No. 4 channel;

[0013] A piston rod, one end of which is connected to the piston ring, and the other end of which passes through the fourth channel and is located in the same space as the third channel;

[0014] A soft cushion sleeve is sleeved on the end of the piston rod, the soft cushion sleeve and the piston rod are fixed by threads, and the soft cushion sleeve is pressed against the bottom of the side valve block.

[0015] Preferably, the sealing structure includes two outer sealing gaskets and an inner sealing gasket that rotate relative to each other, the outer sealing gasket is fixed on the driving shaft and rotates with the driving shaft, the inner sealing gasket is fixed in the front cover and rotates relative to the outer sealing gasket, the end of the inner sealing gasket away from the outer sealing gasket is connected to a spring, a sealing ring is provided on the side of the outer sealing gasket and the inner sealing gasket facing away from each other, the front cover is provided with an end cover on the side facing away from the pump body, the end cover is fixed to the front cover by bolts, the driving shaft passes through the middle of the end cover, and the end cover is pressed against the end of the outer sealing gasket away from the inner sealing gasket.

[0016] Preferably, the driving gear includes an upper right-handed gear and an upper left-handed gear, and the driven gear includes a lower left-handed gear and a lower right-handed gear, wherein the upper right-handed gear is meshed with the lower left-handed gear, and the upper left-handed gear is meshed with the lower right-handed gear, and the thread lines of the upper right-handed gear and the upper left-handed gear are symmetrical to form a herringbone shape, and the driving gear and the driven gear are fixed to the driving shaft and the driven shaft by splines.

[0017] Preferably, bearing sleeves are provided on the driving shaft and the driven shaft at both the front and rear ends of the pump body.

[0018] Preferably, the front cover and the pump body are positioned by providing a plurality of positioning pins.

[0019] Preferably, the pump body and the pump seat are formed into an integrated structure by casting technology.

[0020] Preferably, the elastic device is a spring, and the other end of the elastic device is connected to a valve seat whose height can be adjusted up and down.

[0021] (III) Beneficial effects

[0022] Compared with the prior art, the utility model provides a circular arc gear pump that prevents excessive oil pressure, and has the following beneficial effects:

[0023] 1. The arc gear pump that prevents excessive oil pressure forms an integrated structure of the pump body and the pump seat through casting technology, avoiding oil leakage caused by the gap between the pump body and the pump seat, greatly enhancing the pressure resistance and stability of the gear pump, and making the gear pump greatly anti-fatigue and less prone to bursting, which greatly extends the service life of the gear pump; compared with the split gear pump, the one-piece gear pump can extend its life by twice.

[0024] 2. The arc gear pump for preventing the oil pressure from being too high uses the front cover to support the driving shaft, thus saving the pump seat support structure. Meanwhile, two relatively rotating outer sealing pads and inner sealing pads are arranged on the sealing structure inside the front cover, thus improving the sealing effect at both ends of the driving shaft.

[0025] 3. The circular arc gear pump for preventing the oil pressure from being too high is provided with a detachable safety valve fixed by bolts on the pump body to avoid malfunctions caused by the discharge pressure exceeding the safety pressure. When the discharge pressure is too high or a malfunction occurs in the discharge pipeline, that is, when the discharge pipe valve is closed, the valve body is pushed upward under the action of the pressure in the discharge chamber, thereby opening the connection between the fourth channel and the third channel, and the transported liquid flows back to the suction chamber through the discharge chamber, the second channel, the fourth channel, the third channel and the first channel in turn. When the user does not need the detachable safety valve, it can be disassembled at any time and a special sealing plate can be installed to ensure the safety of the gear pump.

[0026] 4. The arc gear pump for preventing the oil pressure from being too high is provided with an auxiliary push rod device that slides up and down in the side wall of the No. 4 channel. The piston ring at one end of the auxiliary push rod device is pushed upward under the action of the pressure in the No. 2 channel. A soft cushion sleeve is provided on the piston rod at the other end of the auxiliary push rod device. The soft cushion sleeve not only protects the side valve block but also limits the movement of the auxiliary push rod device. When the auxiliary push rod device moves upward, it pushes the valve body upward, thereby preventing the gap opened by the valve body from being unable to release pressure in time. The bottom of the auxiliary push rod device is always located in the No. 2 channel and will not move up to the space in the No. 3 channel like the valve body. When the valve body moves to the space in the No. 3 channel, the effect of the pressure in the No. 2 channel on the valve body will be reduced, thereby failing to open a larger gap according to the pressure. An auxiliary push rod device is provided in the No. 4 channel to assist the valve body in opening, thereby accelerating the effect of reflux pressure relief. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The utility model is a schematic diagram of the structure of the circular arc gear pump for preventing the oil pressure from being too high.

[0028] Figure 2 The utility model is an exploded view of the circular arc gear pump for preventing the oil pressure from being too high.

[0029] Figure 3 The utility model is a cross-sectional view of the circular arc gear pump for preventing excessive oil pressure from being too high, viewed from the front.

[0030] Figure 4 The utility model is a cross-sectional view of the circular arc gear pump for preventing excessive oil pressure from being too high, as viewed from the side.

[0031] Figure 5 For this utility model Figure 4 A partial enlarged view of area A.

[0032] Figure 6 It is a structural schematic diagram of the pump body of the utility model.

[0033] Figure 7 It is a schematic diagram of the structure of the rotating shaft and gears in the pump body of the utility model.

[0034] Figure 8The utility model is a schematic diagram of the internal structure of the detachable safety valve.

[0035] Fig. 9 For this utility model Figure 8 A partial enlarged view of area B in the middle.

[0036] In the figure: 1. pump body; 11. oil suction chamber; 12. oil discharge chamber; 13. channel No. 1; 14. channel No. 2; 2. front cover; 21. sealing structure; 22. end cover; 211. outer sealing gasket; 212. inner sealing gasket; 3. rear cover; 41. driving shaft; 42. driven shaft; 51. driving gear; 52. driven gear; 511. upper right-handed gear; 512. upper left-handed gear; 521. lower left-handed gear; 522. lower right-handed gear; 6. bearing sleeve; 7. detachable safety valve; 71. channel No. 3; 72. channel No. 4; 73. valve body; 74. elastic device; 75. auxiliary push rod device; 751. piston ring; 752. piston rod; 753. cushion sleeve; 731. bottom valve block; 732. side valve block; 8. pump seat. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0038] In the description of the present invention, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0039] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0040] Embodiment 1:

[0041] This embodiment provides a circular arc gear pump that prevents excessive oil pressure and has the following technical features.

[0042] See also Figure 1-9 , a circular arc gear pump for preventing oil pressure from being too high, comprising a pump body 1, a front cover 2 and a rear cover 3 arranged at the front and rear ends of the pump body 1, a driving shaft 41 and a driven shaft 42 are arranged in the pump body 1, and a driving gear 51 and a driven gear 52 meshing with each other are arranged on the driving shaft 41 and the driven shaft 42, one end of the driving shaft 41 passes through the front cover 2, and the other end of the driving shaft 41 and both ends of the driven shaft 42 are located in the pump body 1, a sealing structure 21 is arranged in the front cover 2 at the side position of the driving shaft 41, and a pump seat 8 of an integrated structure is arranged at the bottom of the pump body 1;

[0043] A detachable safety valve 7 is also provided on the pump body 1. An oil suction chamber 11 and an oil discharge chamber 12 are provided on both sides of the driving gear 51 and the driven gear 52 in the pump body 1. The oil suction chamber 11 and the oil discharge chamber 12 are respectively connected to the No. 1 channel 13 and the No. 2 channel 14. The other ends of the No. 1 channel 13 and the No. 2 channel 14 are connected to the contact surface between the pump body 1 and the detachable safety valve 7. A No. 3 channel 71 and a No. 4 channel 72 are connected together in the detachable safety valve 7. A valve body 73 is provided in the No. 4 channel 72. The valve body 73 is connected to an elastic device 74. The detachable safety valve 7 is fixed to the pump body 1 by bolts. The No. 4 channel 72 is aligned with the No. 2 channel 14, and the No. 3 channel 71 is aligned with the No. 1 channel 13. The valve body 73 is stuck in the No. 4 channel 72 under the action of the elastic device 74.

[0044] In an optional embodiment, the cross section of the second channel 14 at the contact surface with the fourth channel 72 is larger than the cross section of the fourth channel 72 at the same position, a bottom valve block 731 is provided at the bottom of the valve body 73, the side of the bottom valve block 731 is an inclined surface, the inclined side wall of the bottom valve block 731 is on the top of the side wall of the fourth channel 72, a side valve block 732 is also provided on the side of the valve body 73, the bottom of the side valve block 732 is a plane, and a plurality of auxiliary push rod devices 75 uniformly distributed in a circle that slide up and down are also provided in the side wall of the fourth channel 72, and the auxiliary push rod device 75 includes:

[0045] A piston ring 751, one end of the piston ring 751 is located in the same space as the second channel 14, and the other end is fixed to the piston rod 752, and the side surface of the piston ring 751 is tightly fitted inside the side wall of the fourth channel 72;

[0046] A piston rod 752, one end of the piston rod 752 is connected to the piston ring 751, and the other end passes through the fourth channel 72 and is located in the same space as the third channel 71;

[0047] The cushion sleeve 753 is sleeved on the end of the piston rod 752 . The cushion sleeve 753 and the piston rod 752 are fixed by threads. The cushion sleeve 753 is pressed against the bottom of the side valve block 732 .

[0048] In an optional embodiment, the sealing structure 21 includes two relatively rotating outer sealing gaskets 211 and an inner sealing gasket 212. The outer sealing gasket 211 is fixed on the driving shaft 41 and rotates with the driving shaft 41. The inner sealing gasket 212 is fixed in the front cover 2 and rotates relatively to the outer sealing gasket 211. The end of the inner sealing gasket 212 away from the outer sealing gasket 211 is connected to a spring. A sealing ring is arranged on the side of the outer sealing gasket 211 and the inner sealing gasket 212 facing away from each other. The front cover 2 is provided with an end cover 22 on the side facing away from the pump body 1. The end cover 22 is fixed to the front cover 2 by bolts. The driving shaft 41 passes through the middle of the end cover 22, and the end cover 22 is pressed against the end of the outer sealing gasket 211 away from the inner sealing gasket 212.

[0049] In an optional embodiment, the driving gear 51 includes an upper right-handed gear 511 and an upper left-handed gear 512, and the driven gear 52 includes a lower left-handed gear 521 and a lower right-handed gear 522, wherein the upper right-handed gear 511 is meshed with the lower left-handed gear 521, and the upper left-handed gear 512 is meshed with the lower right-handed gear 522, and the thread lines of the upper right-handed gear 511 and the upper left-handed gear 512 are symmetrically formed in a herringbone shape, and the driving gear 51 and the driven gear 52 are fixed to the driving shaft 41 and the driven shaft 42 by splines.

[0050] In an optional embodiment, bearing sleeves 6 are provided on the driving shaft 41 and the driven shaft 42 at both the front and rear ends of the pump body 1 .

[0051] In an optional embodiment, the front cover 2 and the pump body 1 are positioned by providing a plurality of positioning pins.

[0052] In an optional embodiment, the pump body 1 and the pump seat 8 are formed into an integrated structure by casting technology.

[0053] In an optional embodiment, the elastic device 74 is a spring, and the other end of the elastic device 74 is connected to a valve seat whose height can be adjusted up and down.

[0054] To sum up, the circular arc gear pump which prevents excessive oil pressure forms an integrated structure of the pump body 1 and the pump seat 8 through casting technology, which avoids oil leakage caused by the gap between the pump body 1 and the pump seat 8, greatly enhances the pressure resistance and stability of the gear pump, and greatly enhances the fatigue resistance of the gear pump, making it less prone to bursting, which greatly extends the service life of the gear pump; compared with the split gear pump, the one-piece gear pump can extend its life by twice.

[0055] The arc gear pump for preventing the oil pressure from being too high utilizes the front cover 2 to support the driving shaft 41, thus saving the pump seat supporting structure. Meanwhile, two relatively rotating outer sealing pads 211 and inner sealing pads 212 are arranged on the sealing structure 21 in the front cover 2, thus improving the sealing effect at both inner and outer ends of the driving shaft 41.

[0056] The circular arc gear pump for preventing the oil pressure from being too high is provided with a detachable safety valve 7 fixed by bolts on the pump body 1 to avoid malfunctions caused by the discharge pressure exceeding the safety pressure. When the discharge pressure is too high or a malfunction occurs in the oil discharge pipeline, that is, when the oil discharge pipe valve is closed, the valve body 73 is pushed upward under the action of the pressure in the oil discharge chamber 12, thereby opening the connection between the fourth channel 72 and the third channel 71, and the transported liquid flows back to the oil suction chamber 11 through the oil discharge chamber 12, the second channel 14, the fourth channel 72, the third channel 71, and the first channel 13 in sequence. When the user does not need the detachable safety valve 7, it can be removed at any time and a special sealing plate can be installed to ensure the safety of the gear pump.

[0057] The arc gear pump for preventing the oil pressure from being too high is provided with an auxiliary push rod device 75 that slides up and down in the side wall of the fourth channel 72. The piston ring 751 at one end of the auxiliary push rod device 75 pushes upward under the action of the pressure in the second channel 14, and a soft cushion sleeve 753 is provided on the piston rod 752 at the other end of the auxiliary push rod device 75. The soft cushion sleeve 753 not only protects the side valve block 732 but also limits the movement of the auxiliary push rod device 75. When the auxiliary push rod device 75 moves upward, it pushes the valve body 73 upward, thereby avoiding that the gap opened by the valve body 73 cannot be depressurized in time. The bottom of the auxiliary push rod device 75 is always located in the second channel 14 and will not move up to the space in the third channel 71 like the valve body 73. When the valve body 73 moves to the space in the third channel 71, the effect of the pressure in the second channel 14 on the valve body 73 will be reduced, so that it cannot open a larger gap according to the pressure. The auxiliary push rod device 75 is provided in the fourth channel 72 to assist the valve body 73 in opening, thereby accelerating the effect of reflux pressure relief.

[0058] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0059] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A circular arc gear pump for preventing oil pressure from being too high, comprising a pump body (1), a front cover (2) and a rear cover (3) arranged at the front and rear ends of the pump body (1), a driving shaft (41) and a driven shaft (42) being arranged in the pump body (1), and a driving gear (51) and a driven gear (52) meshing with each other being arranged on the driving shaft (41) and the driven shaft (42), characterized in that: One end of the driving shaft (41) passes through the front cover (2), the other end of the driving shaft (41) and both ends of the driven shaft (42) are located in the pump body (1), a sealing structure (21) is provided in the front cover (2) at the side of the driving shaft (41), and a pump seat (8) of an integrated structure is provided at the bottom of the pump body (1); The pump body (1) is also provided with a detachable safety valve (7). An oil suction chamber (11) and an oil discharge chamber (12) are provided on both sides of the driving gear (51) and the driven gear (52) in the pump body (1). The oil suction chamber (11) and the oil discharge chamber (12) are respectively connected to a first channel (13) and a second channel (14). The other ends of the first channel (13) and the second channel (14) are connected to the contact surface between the pump body (1) and the detachable safety valve (7). The detachable safety valve (7) A third channel (71) and a fourth channel (72) are provided therein and are connected to each other. A valve body (73) is provided in the fourth channel (72). The valve body (73) is connected to an elastic device (74). The detachable safety valve (7) is fixed to the pump body (1) by bolts. The fourth channel (72) is aligned with the second channel (14). The third channel (71) is aligned with the first channel (13). The valve body (73) is stuck in the fourth channel (72) under the action of the elastic device (74); The sealing structure (21) comprises two outer sealing pads (211) and an inner sealing pad (212) that rotate relative to each other. The outer sealing pad (211) is fixed on the driving shaft (41) and rotates with the driving shaft (41). The inner sealing pad (212) is fixed in the front cover (2) and rotates relative to the outer sealing pad (211). An end of the inner sealing pad (212) that is away from the outer sealing pad (211) is connected to a spring. A sealing ring is provided on the side of the outer sealing pad (211) and the inner sealing pad (212) that are opposite to each other. The front cover (2) is provided with an end cover (22) on the side that is away from the pump body (1). The end cover (22) is fixed to the front cover (2) by bolts. The driving shaft (41) passes through the middle of the end cover (22). The end cover (22) is pressed against an end of the outer sealing pad (211) that is away from the inner sealing pad (212).

2. A circular arc gear pump for preventing excessive oil pressure according to claim 1, characterized in that: The cross section of the No. 2 channel (14) at the contact surface with the No. 4 channel (72) is larger than the cross section of the No. 4 channel (72) at the same position; a bottom valve block (731) is provided at the bottom of the valve body (73); the side surface of the bottom valve block (731) is an inclined surface; the inclined side wall of the bottom valve block (731) is pressed against the top of the side wall of the No. 4 channel (72); a side valve block (732) is further provided on the side surface of the valve body (73); the bottom of the side valve block (732) is a flat surface; a plurality of auxiliary push rod devices (75) evenly distributed in a circumference and sliding up and down are further provided in the side wall of the No. 4 channel (72); the auxiliary push rod device (75) comprises: A piston ring (751), one end of the piston ring (751) is located in the same space as the second channel (14), and the other end is fixedly connected to the piston rod (752), and the side surface of the piston ring (751) is tightly fitted inside the side wall of the fourth channel (72); A piston rod (752), one end of the piston rod (752) is connected to the piston ring (751), and the other end of the piston rod (752) passes through the fourth channel (72) and is located in the same space as the third channel (71); A soft cushion sleeve (753), the soft cushion sleeve (753) is sleeved on the end of the piston rod (752), the soft cushion sleeve (753) and the piston rod (752) are fixed via threads, and the soft cushion sleeve (753) is pressed against the bottom of the side valve block (732).

3. The circular arc gear pump for preventing excessive oil pressure according to claim 1, characterized in that: The driving gear (51) comprises an upper right-handed gear (511) and an upper left-handed gear (512); the driven gear (52) comprises a lower left-handed gear (521) and a lower right-handed gear (522); the upper right-handed gear (511) meshes with the lower left-handed gear (521); the upper left-handed gear (512) meshes with the lower right-handed gear (522); the thread lines of the upper right-handed gear (511) and the upper left-handed gear (512) are symmetrical to form a herringbone shape; the driving gear (51) and the driven gear (52) are fixed to the driving shaft (41) and the driven shaft (42) via splines.

4. The circular arc gear pump for preventing excessive oil pressure according to claim 1, characterized in that: Bearing sleeves (6) are provided on the driving shaft (41) and the driven shaft (42) at both the front and rear ends of the pump body (1).

5. The circular arc gear pump for preventing excessive oil pressure according to claim 1, characterized in that: The front cover (2) and the pump body (1) are positioned by providing a plurality of positioning pins.

6. The circular arc gear pump for preventing excessive oil pressure according to claim 1, characterized in that: The pump body (1) and the pump seat (8) are formed into an integrated structure by using a casting technique.

7. The circular arc gear pump for preventing excessive oil pressure according to claim 1, characterized in that: The elastic device (74) is a spring, and the other end of the elastic device (74) is connected to a valve seat whose height can be adjusted up and down.

Images