A miniature gear pump and a vehicle suspension lifting unit

Abstract

This invention relates to a micro gear pump in the field of hydraulic pump technology. The driving gear shaft (1) extends into the first bushing hole (3). The lower end face of the floating bushing (2) is in contact with the upper end face of the driving gear (4), and the upper end face of the floating bushing (2) is close to the cover plate (5). A first compensation oil chamber (7) is formed between the upper end face of the floating bushing (2) and the cover plate (5) on one side of the first oil chamber (6). The driven gear shaft (8) extends into the second bushing hole (9) of the floating bushing (2). The lower end face of the floating bushing (2) is in contact with the upper end face of the driven gear (10), and the upper end face of the floating bushing (2) is close to the cover plate (5). A second oil chamber (11) connecting the floating bushing (2), the driven gear (10), and the cover plate (5) on one side of the pump housing (13) is formed between the upper end face of the floating bushing (2) and the cover plate (5) on one side of the second oil chamber (11). A second compensation oil chamber (12) is formed between the upper end face of the floating bushing (2) and the cover plate (5) on one side of the second oil chamber (11). The structure of this invention enables automatic axial clearance compensation and low-pressure lubrication.

Description

Technical Field

[0001] This invention belongs to the field of hydraulic pump technology, and more specifically, relates to a miniature gear pump. This invention also relates to a vehicle suspension lifting unit using the miniature gear pump described above. Background Technology

[0002] Current Status of Miniature Hydraulic Pumps: In space- and weight-sensitive applications such as vehicles and robots, the miniaturization and high-pressure requirements of hydraulic systems are urgent. Currently, there are two main technological approaches for miniature gear pumps: Internal gear pumps: This structure, with its advantages of good tooth surface contact and low flow pulsation, easily achieves high unidirectional reciprocating working pressure. However, its high-pressure performance heavily relies on high-precision crescent plates / blocks and complex clearance compensation mechanisms, resulting in high manufacturing costs at the miniature scale. More importantly, the position of its high-pressure chamber is determined by the fixed crescent plate, making it difficult to achieve efficient and equivalent bidirectional output in its structural principle, greatly limiting its application in systems requiring bidirectional drive (such as suspension lifting). External gear pumps: This structure has a simple principle, mature technology, and lower cost, and the high and low pressure chambers switch with the direction of rotation, possessing a natural advantage in bidirectional operation. However, when the size is miniaturized, the proportion of axial clearance leakage in the total leakage increases sharply, becoming the most critical factor restricting the increase of working pressure. Existing axial clearance compensation designs (such as floating side plates) are mostly found in industrial external gear pumps (the gear diameter is usually greater than φ40mm, and the side plate floats through complex hydraulic circuits and valves) and miniature unidirectional external gear pumps. However, bidirectional external gear pumps of the same size are mostly low-pressure pumps (lacking axial clearance compensation design, with low efficiency, high wear, and short lifespan when used at high pressure), making it difficult to simultaneously meet the three requirements of "miniature", "stable medium and high pressure", and "bidirectional operation", which has become a long-standing unsolved problem under this technical approach.

[0003] Existing technology includes a novel fully active hydraulic suspension system and vehicle, with publication number "A Novel Fully Active Hydraulic Suspension System and Vehicle". This system comprises a shock absorber assembly and an electric pump assembly. The shock absorber assembly includes two shock absorbers, left and right, with damping valves connected to their upper and lower chambers. The electric pump assembly includes a motor and a double gear pump. The double gear pump comprises two hydraulic pumps sharing a single drive shaft, with the motor's output shaft connected to the drive shaft. The inlet and outlet ports of each hydraulic pump are connected to the two damping valves of one shock absorber via electromagnetic directional valves, forming a hydraulic circuit between the upper and lower chambers of the shock absorber and the hydraulic pumps. An accumulator is connected to the hydraulic circuit. This invention's technical solution ensures smooth driving and handling stability while reducing the chassis space occupied by the suspension system. However, this technology does not address the technical problems and solutions of this application. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a miniature gear pump that can achieve automatic axial clearance compensation and low-pressure lubrication, in order to overcome the shortcomings of the prior art.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: This invention relates to a miniature gear pump. A shaped sealing ring 18 is located between a cover plate 5 and a floating bushing 2. The shaped sealing ring 18, the cover plate 5, and the floating bushing 2 form a first compensation oil chamber 7 on one side, and a second compensation oil chamber 12 on the other side. The first compensation oil chamber 7 is connected to a first oil inlet 14 on the cover plate 5 equipped with a first check valve 28. The second compensation oil chamber 12 is connected to a second oil inlet 16 on the cover plate 5 equipped with a second check valve 47. The first compensation oil chamber 7 is connected to a first oil chamber 6 of the gear pair. The first oil chamber 6 of the gear pair is connected to a first oil outlet 15. The second compensation oil chamber 12 is connected to a second oil chamber 11 of the gear pair. The second oil chamber 11 of the gear pair is connected to a second oil outlet 17.

[0006] When the driving gear shaft 1 drives the driving gear 4 to rotate clockwise, the first compensation oil chamber 7 of the floating bushing 2 on the first oil chamber 6 side of the gear pair forms a high-pressure compensation area A19, and the lower end face of the floating bushing 2 on the first oil chamber 6 side of the gear pair and the upper end face of the driving gear 4 and the driven gear 10 form an equivalent working area B20; when the driving gear shaft 1 drives the driving gear 4 to rotate counterclockwise, the second compensation oil chamber 12 of the floating bushing 2 on the second oil chamber 11 side of the gear pair forms a high-pressure compensation area A19, and the lower end face of the floating bushing 2 on the second oil chamber 11 side of the gear pair and the upper end face of the driving gear 4 and the driven gear 10 form an equivalent working area B20, and the oil working area of ​​the high-pressure compensation area A19 is greater than the oil working area of ​​the equivalent working area B20.

[0007] The micro gear pump has a gear pair inside the pump housing 13, which includes a driving gear 4 and a driven gear 10. The driving gear 4 is connected to the driving gear shaft 1, and the driven gear 10 is connected to the driven gear shaft 8. The driving gear shaft 1 has an axial oil hole 21 inside, and the driven gear shaft 8 has an axial oil hole 22 inside.

[0008] A low-pressure lubricating oil cavity 46 is also formed between the irregular sealing ring 18, the cover plate 5, and the floating bushing 2. The low-pressure lubricating oil cavity 46 is connected to the axial oil hole 21 of the driving gear shaft through a through hole on the floating bushing 2, and the low-pressure lubricating oil cavity 46 is connected to the axial oil hole 22 of the driven gear shaft through another through hole on the floating bushing 2.

[0009] When the drive gear shaft 1 extends into the first bushing hole 3, the drive gear shaft axial oil hole 21 is provided with a drive gear shaft radial oil hole 33 near the lower part, and the drive gear shaft radial oil hole 33 connects the annular groove 34 between the drive gear shaft 1 and the first bushing hole 3 in the pump housing 13; when the driven gear shaft 8 extends into the second bushing hole 9, a gap is formed between the driven gear shaft 8 and the second bushing hole 9 of the pump housing 13, and the driven gear shaft axial oil hole 22 connects to the gap.

[0010] The first oil inlet 14 and the second oil inlet 16 are respectively connected to the hydraulic oil tank 40, the low-pressure lubricating oil chamber 46 is connected to the hydraulic oil tank 40, and the upper end of the pump housing 13 is connected to the valve seat plate 25.

[0011] The spring 29 at the lower end of the first one-way valve 28 is fitted into the positioning groove on the cover plate 5, and the valve core 30 at the upper end of the first one-way valve 28 abuts against the positioning step of the first oil inlet 14. The spring 29 at the lower end of the second one-way valve 47 is fitted into the positioning groove on the cover plate 5, and the valve core 30 at the upper end of the second one-way valve 47 abuts against the positioning step of the second oil inlet 16.

[0012] On the side of the drive gear shaft 1, a portion of the oil entering the axial oil hole 21 of the drive gear shaft from the low-pressure lubrication oil chamber 46 enters the first bushing hole oil groove 31 to lubricate the bushing friction pair formed by the floating bushing 2 and the drive gear shaft 1 in the upper half of the drive gear. Another portion of the oil enters the annular groove 34 through the axial oil hole 21 and the radial oil hole 33 of the drive gear shaft to lubricate the bushing friction pair formed by the drive gear shaft 1 and the pump housing 13 in the lower half of the drive gear 4. On the side of the driven gear shaft 8, a portion of the oil entering the axial oil hole 22 of the driven gear shaft from the low-pressure lubrication oil chamber 46 enters the second bushing hole oil groove 32 through the gap to lubricate the bushing friction pair formed by the floating bushing 2 and the driven gear shaft 8 in the upper half of the driven gear shaft 8. Another portion of the oil enters the gap through the axial oil hole 22 of the driven gear shaft to lubricate the bushing friction pair formed by the driven gear shaft 8 and the pump housing 13 in the lower half of the driven gear 10.

[0013] The present invention also relates to a vehicle suspension lifting unit using the micro gear pump described above. The micro gear pump is installed inside the pump housing 13. The drive gear shaft 1 is connected to the drive shaft 39 of the drive motor 38. An oil tank 40 is provided at one end of the motor housing. A movable piston 41 is provided inside the oil tank 40. The piston 41 divides the oil tank 40 into an upper chamber 42 and a lower chamber 43. The medium in the upper chamber 42 is air, and the medium in the lower chamber 43 is oil. The upper chamber 42 is connected to a vent plug 44 on the oil tank 40. A piston sealing ring 45 is provided on the outer ring of the movable piston 41.

[0014] The working principle and beneficial effects of the technical solution adopted in this invention are as follows: The micro gear pump of the present invention is structurally designed to form an axial clearance compensation system inside the pump. Specifically, by using a specially designed irregularly shaped sealing ring 18, after the ring is installed between the cover plate 5 and the floating bushing 2, a first compensation oil chamber 7 is formed on one side of the irregularly shaped sealing ring 18, the cover plate 5, and the floating bushing 2. A second compensation oil chamber 12 is formed on the other side. The first compensation oil chamber 7 is connected to a first oil inlet 14 on the cover plate 5 equipped with a first check valve 28, which is used for hydraulic oil entry. The second compensation oil chamber 12 is connected to a second oil inlet 16 on the cover plate 5 equipped with a second check valve 47, which is also used for hydraulic oil entry. In the above structure, when oil enters through the first oil inlet 14, the first compensation oil chamber 7 is in a low-pressure state, the first oil chamber 6 of the gear pair connected to the first compensation oil chamber 7 is in a low-pressure state, and the first oil outlet 15 is in a low-pressure state. Under the action of the gear pair, the second compensation oil chamber 12 is in a high-pressure state, the second oil chamber 11 of the gear pair connected to the second compensation oil chamber 12 is in a high-pressure state, and the second oil outlet 17 is in a high-pressure state. At this time, the second oil inlet 16 is in a closed state, and the high-pressure hydraulic oil from the second oil outlet 17 enters the oil cylinder, pushing the piston to move and realizing the lifting control of the vehicle suspension lifting unit. During this process, the high-pressure hydraulic oil in the second oil chamber 11 of the gear pair enters the second compensation oil chamber 12 through the hydraulic oil channel on the side of the floating bushing 2, acting on the upper surface of the floating bushing 2 and applying pressure to the upper surface of the floating bushing 2, pressing the floating bushing 2 closer to the gear pair. In this way, even if the surface of the floating bushing 2 wears due to long-term operation, the hydraulic pressure can push the floating bushing 2 to automatically shift and compensate towards the upper surface of the gear pair, ensuring the stability of the oil film gap. When oil enters through the second oil inlet 16, the second compensation oil chamber 12 is in a low-pressure state, the second oil chamber 11 of the gear pair connected to the second compensation oil chamber 12 is in a low-pressure state, and the second oil outlet 17 is in a low-pressure state. Under the action of the gear pair, the first compensation oil chamber 7 is in a high-pressure state, the first oil chamber 6 of the gear pair connected to the first compensation oil chamber 7 is in a high-pressure state, and the first oil outlet 15 is in a high-pressure state. At this time, the first oil inlet 14 is in a closed state, and the high-pressure hydraulic oil from the first oil outlet 15 enters the cylinder, pushing the piston to move and realizing the lifting control of the vehicle suspension lifting unit. During this process, the high-pressure hydraulic oil in the first oil chamber 6 of the gear pair enters the first compensation oil chamber 7 through the hydraulic oil channel on the side of the floating bushing 2, and acts on the upper end surface of the floating bushing 2, applying pressure to the upper end surface of the floating bushing 2 and pressing the floating bushing 2 closer to the gear pair. In this way, even if the surface of the floating bushing 2 is worn due to long-term operation, the hydraulic pressure can push the floating bushing 2 to automatically shift and compensate towards the upper end surface of the gear pair, ensuring the stability of the oil film gap.Therefore, regardless of whether the gear pair rotates forward or backward, high-pressure oil acts on the corresponding compensation oil chamber, applying pressure to the upper end face of the floating sleeve 2. This pressure pushes the floating sleeve 2 to automatically shift and compensate towards the upper end face of the gear pair, ensuring stable oil film clearance and improving pump performance and lifespan. Simultaneously, through communication between the corresponding parts of the gear pair and the low-pressure lubrication oil chamber 46, a stable low-pressure oil source can be provided to the corresponding parts of the gear pair, continuously providing lubrication and cooling to the support sleeves at both ends of the gear shaft, ensuring long-term reliable pump operation under high pressure. A one-way valve with extremely low opening pressure is installed at each of the two oil inlets to ensure reliable opening during oil intake, ensuring smooth oil suction and effectively meeting usage requirements. Attached Figure Description

[0015] The following is a brief explanation of the contents depicted in the accompanying drawings and the markings therein: Figure 1 This is an exploded structural diagram of the micro gear pump described in this invention; Figure 2 This is a partial cross-sectional view of the micro gear pump described in this invention. Figure 3 This is a partial cross-sectional view of the micro gear pump described in this invention. Figure 4 This is a schematic diagram of the mating structure of the floating bushing and the irregularly shaped sealing ring of the micro gear pump described in this invention; Figure 5 This is a schematic diagram of the structure of the lower surface of the gear pair in the micro gear pump of the present invention; Figure 6 This is a cross-sectional view of the lifting unit described in this invention. Figure 7 This is a cross-sectional view of the pump head of the lifting unit described in this invention. Figure 8 This is a schematic diagram of the hydraulic principle of the lifting unit described in this invention; Figure 9 This is a schematic diagram of the control logic of the lifting unit described in this invention; The labels in the attached diagram are as follows: 1. Drive gear shaft; 2. Floating bushing; 3. First bushing hole; 4. Drive gear; 5. Cover plate; 6. First oil chamber; 7. First compensation oil chamber; 8. Driven gear shaft; 9. Second bushing hole; 10. Driven gear; 11. Second oil chamber; 12. Second compensation oil chamber; 13. Pump housing; 14. First oil inlet; 15. First oil outlet; 16. Second oil inlet; 17. Second oil outlet; 18. Shaped sealing ring; 19. High-pressure compensation area A; 20. Equivalent working area B; 21. Axial oil hole of drive gear shaft; 22. Axial oil hole of driven gear shaft; 2 3. Hydraulic check valve; 24. Flow control valve; 25. Valve seat plate; 26. Relief valve; 27. Hydraulic oil tank; 28. First check valve; 29. ​​Spring; 30. Valve core; 31. First bushing hole oil groove; 32. Second bushing hole oil groove; 33. Radial oil hole of drive gear shaft; 34. Annular groove; 35. Plug; 36. Throttle valve; 38. Drive motor; 39. Drive shaft; 40. Oil tank; 41. Piston; 42. Upper chamber; 43. Lower chamber; 44. Breather plug; 45. Piston seal ring; 46. Low-pressure lubricating oil chamber; 47. Second check valve; 48. Lifting cylinder; 49. Oil pump. Detailed Implementation

[0016] The following description, with reference to the accompanying drawings, provides a more detailed explanation of the specific embodiments of the present invention, including the shape and structure of each component, the relative positions and connections between the parts, the functions and working principles of each part: As attached Figure 1 - Appendix Figure 9As shown, this invention relates to a miniature gear pump. A shaped sealing ring 18 is located between a cover plate 5 and a floating bushing 2. The shaped sealing ring 18, cover plate 5, and floating bushing 2 form a first compensation oil chamber 7 on one side, and a second compensation oil chamber 12 on the other side. The first compensation oil chamber 7 connects to a first oil inlet 14 on cover plate 5 equipped with a first one-way valve 28. The second compensation oil chamber 12 connects to a second oil inlet 16 on cover plate 5 equipped with a second one-way valve 47. The first compensation oil chamber 7 connects to a first oil chamber 6 of the gear pair, which in turn connects to a first oil outlet 15. The second compensation oil chamber 12 connects to a second oil chamber 11 of the gear pair, which in turn connects to a second oil outlet 17. This invention addresses the shortcomings of existing technologies by proposing an improved technical solution. In this structural design, an axial clearance compensation system is formed inside the miniature gear pump. That is to say, by setting a specially shaped sealing ring 18, after the special-shaped sealing ring is installed between the cover plate 5 and the floating bushing 2, the special-shaped sealing ring 18 and the cover plate 5 and the floating bushing 2 form a first compensation oil chamber 7 on one side, and the special-shaped sealing ring 18 and the cover plate 5 and the floating bushing 2 form a second compensation oil chamber 12 on the other side. The first compensation oil chamber 7 is connected to the first oil inlet 14 with a first check valve 28 on the cover plate 5. The first oil inlet 14 is used for hydraulic oil to enter. The second compensation oil chamber 12 is connected to the second oil inlet 16 with a check valve 47 on the cover plate 5. The second oil inlet 16 is used for hydraulic oil to enter. In the above structure, when oil enters through the first oil inlet 14, the first compensation oil chamber 7 is in a low-pressure state, the first oil chamber 6 of the gear pair connected to the first compensation oil chamber 7 is in a low-pressure state, and the first oil outlet 15 is in a low-pressure state. Under the action of the gear pair, the second compensation oil chamber 12 is in a high-pressure state, the second oil chamber 11 of the gear pair connected to the second compensation oil chamber 12 is in a high-pressure state, and the second oil outlet 17 is in a high-pressure state. At this time, the second oil inlet 16 is in a closed state, and the high-pressure hydraulic oil from the second oil outlet 17 enters the lifting cylinder 48, pushing the piston to move and realizing the lifting control of the vehicle suspension lifting unit. During this process, the high-pressure hydraulic oil in the second oil chamber 11 of the gear pair enters the second compensation oil chamber 12 through the hydraulic oil channel on the side of the floating bushing 2, and acts on the upper end surface of the floating bushing 2, applying pressure to the upper end surface of the floating bushing 2 and pressing the floating bushing 2 closer to the gear pair. In this way, even if the surface of the floating bushing 2 is worn due to long-term operation, the hydraulic pressure can push the floating bushing 2 to automatically shift and compensate towards the upper end surface of the gear pair, ensuring the stability of the oil film gap.When oil enters through the second oil inlet 16, the second compensation oil chamber 12 is in a low-pressure state, the second oil chamber 11 of the gear pair connected to the second compensation oil chamber 12 is in a low-pressure state, and the second oil outlet 17 is in a low-pressure state. Under the action of the gear pair, the first compensation oil chamber 7 is in a high-pressure state, the first oil chamber 6 of the gear pair connected to the first compensation oil chamber 7 is in a high-pressure state, and the first oil outlet 15 is in a high-pressure state. At this time, the first oil inlet 14 is in a closed state, and the high-pressure hydraulic oil from the first oil outlet 15 enters the cylinder, pushing the piston to move and realizing the lifting control of the vehicle suspension lifting unit. During this process, the high-pressure hydraulic oil from the first oil chamber 6 of the gear pair enters the first compensation oil chamber 7 through the hydraulic oil channel on the side of the floating bushing 2, acting on the upper end surface of the floating bushing 2, applying pressure to the upper end surface of the floating bushing 2, and pressing the floating bushing 2 closer to the gear pair. In this way, even if the surface of the floating bushing 2 wears due to long-term operation, the hydraulic pressure can push the floating bushing 2 to automatically shift and compensate towards the upper end surface of the gear pair, ensuring the stability of the oil film gap. Therefore, whether the gear pair rotates forward or backward, high-pressure oil acts on the corresponding compensation oil chamber, applying pressure to the upper end face of the floating bushing 2 to push the floating bushing 2 to automatically shift and compensate towards the upper end face of the gear pair, ensuring stable oil film clearance and improving pump performance and lifespan.

[0017] When the driving gear shaft 1 drives the driving gear 4 to rotate clockwise, the first compensation oil chamber 7 of the floating sleeve 2 on the first oil chamber 6 side of the gear pair forms a high-pressure compensation area A19. The lower end face of the floating sleeve 2 on the first oil chamber 6 side of the gear pair and the upper end face of the driving gear 4 and the driven gear 10 form an equivalent working area B20. When the driving gear shaft 1 drives the driving gear 4 to rotate counterclockwise, the second compensation oil chamber 12 of the floating sleeve 2 on the second oil chamber 11 side of the gear pair forms a high-pressure compensation area A19. The lower end face of the floating sleeve 2 on the second oil chamber 11 side of the gear pair and the upper end face of the driving gear 4 and the driven gear 10 form an equivalent working area B20. The oil working area of ​​the high-pressure compensation area A19 is greater than the oil working area of ​​the equivalent working area B20. With the above structure, regardless of whether the pump works clockwise or counterclockwise, in the initial stage, the initial compression of the irregular sealing ring 18 provides a certain thrust to push the floating sleeve 2 towards the gear end face, forming a sealing oil film and quickly building pressure. When the micro pump is electrically started, the motor drives the drive gear shaft to rotate and begin operation. Once the hydraulic oil pressure is established, the floating sleeve 2 mainly applies pressure in the corresponding high-pressure compensation chamber. Specifically, the oil action area of ​​the upper high-pressure compensation area A19 is greater than that of the lower equivalent action area B20, which keeps the floating sleeve 2 pressed towards the gear pair, thus maintaining the sealing oil film. The ratio of the high-pressure compensation area A19 to the equivalent action area B20 is generally designed to be 1.2, but is adjusted according to the actual operating conditions of the pump. Due to the area difference, a pressure is generated on one side of the high-pressure compensation chamber, acting on the high-pressure compensation area A19, thereby generating a net clamping force that presses the floating sleeve 2 against the gear end face, thus dynamically reducing the axial oil film gap at the gear end face and achieving efficient sealing.

[0018] In the structure of this invention, the lifting cylinder is divided into an upper chamber and a lower chamber by a cylinder piston. A first oil outlet 15 connects to the lower chamber, and a second oil outlet 17 connects to the upper chamber. When high-pressure hydraulic oil enters the lower chamber through the first oil outlet 15, the cylinder piston moves upward, achieving lifting. When high-pressure hydraulic oil enters the upper chamber through the second oil outlet 17, the piston moves downward, achieving descent. Thus, the suspension lifting unit is reliably controlled by a micro gear pump.

[0019] The micro gear pump has a gear pair inside the pump casing 13, including a driving gear 4 and a driven gear 10. The driving gear 4 is connected to the driving gear shaft 1, and the driven gear 10 is connected to the driven gear shaft 8. The driving gear shaft 1 has an axial oil hole 21, and the driven gear shaft 8 has an axial oil hole 22. A low-pressure lubricating oil chamber 46 is formed between the irregular sealing ring 18, the cover plate 5, and the floating bushing 2. The low-pressure lubricating oil chamber 46 is connected to the axial oil hole 21 of the driving gear shaft through one through hole on the floating bushing 2, and to the axial oil hole 22 of the driven gear shaft through another through hole on the floating bushing 2. With this structure, the low-pressure lubricating oil chamber 46 can enter the axial oil holes 21 and 22 of the driving gear shaft, providing low-pressure lubricating oil to the corresponding friction pair positions, realizing low-pressure lubrication of the corresponding parts of the gear pair, and effectively improving service life.

[0020] When the drive gear shaft 1 extends into the first bushing hole 3, a radial oil hole 33 is provided near the lower part of the axial oil hole 21 of the drive gear shaft. The radial oil hole 33 of the drive gear shaft connects to the annular groove 34 between the drive gear shaft 1 and the first bushing hole 3 in the pump housing 13. In this structure, low-pressure lubricating oil achieves lubrication. When the driven gear shaft 8 extends into the second bushing hole 9, a gap is formed between the driven gear shaft 8 and the second bushing hole 9 of the pump housing 13. The axial oil hole 22 of the driven gear shaft connects to this gap. In this structure, low-pressure lubricating oil achieves lubrication.

[0021] The first oil inlet 14 and the second oil inlet 16 are respectively connected to the hydraulic oil tank 27, and the low-pressure lubricating oil chamber 46 is also connected to the hydraulic oil tank 27. The upper end of the pump housing 13 is connected to the valve seat plate 25. In this structure, the oil tank supplies lubricating oil, and the corresponding oil inlet is opened by the forward and reverse rotation of the gear pair to achieve oil supply. When the gear pair rotates forward, oil enters through the first oil inlet, and at this time, the second oil inlet closes the second check valve under the action of high-pressure oil pressure. When the gear pair rotates in reverse, oil enters through the second oil inlet, and at this time, the second check valve closes the first oil inlet under the action of high-pressure oil pressure. The pump housing 13 and the valve seat plate 25 are reliably connected to form a structurally reliable micro pump.

[0022] The spring 29 at the lower end of the first one-way valve 28 is fitted into the positioning groove on the cover plate 5, and the valve core 30 at the upper end of the first one-way valve 28 abuts against the positioning step of the first oil inlet 14. The spring 29 at the lower end of the second one-way valve 47 is fitted into the positioning groove on the cover plate 5, and the valve core 30 at the upper end of the second one-way valve 47 abuts against the positioning step of the second oil inlet 16.

[0023] On the side of the drive gear shaft 1, a portion of the oil entering the axial oil hole 21 of the drive gear shaft from the low-pressure lubrication oil chamber 46 enters the first bushing hole oil groove 31 to lubricate the bushing friction pair formed by the floating bushing 2 and the drive gear shaft 1 in the upper half of the drive gear. Another portion of the oil enters the annular groove 34 through the axial oil hole 21 and the radial oil hole 33 of the drive gear shaft to lubricate the bushing friction pair formed by the drive gear shaft 1 and the pump housing 13 in the lower half of the drive gear 4. On the side of the driven gear shaft 8, a portion of the oil entering the axial oil hole 22 of the driven gear shaft from the low-pressure lubrication oil chamber 46 enters the second bushing hole oil groove 32 through the gap to lubricate the bushing friction pair formed by the floating bushing 2 and the driven gear shaft 8 in the upper half of the driven gear shaft 8. Another portion of the oil enters the gap through the axial oil hole 22 of the driven gear shaft to lubricate the bushing friction pair formed by the driven gear shaft 8 and the pump housing 13 in the lower half of the driven gear 10. The aforementioned structure, connected to the low-pressure lubrication chamber 46, provides a stable low-pressure oil source, continuously lubricating and cooling the support bushings at both ends of the gear shaft, ensuring long-term reliable operation of the pump under high pressure. Each of the two oil inlets is equipped with a one-way valve with extremely low opening pressure to ensure reliable opening during oil intake, ensuring smooth oil suction and effectively meeting usage requirements.

[0024] The present invention also relates to a highly integrated vehicle suspension lifting unit that utilizes the aforementioned micro gear pump to form a simplified system, reduce leakage points, and improve reliability.

[0025] In the vehicle suspension lifting unit using the aforementioned micro gear pump, the micro gear pump is installed inside the pump housing 13. The drive gear shaft 1 is connected to the drive shaft 39 of the drive motor 38. An oil tank 40 is located at one end of the motor housing. A movable piston 41 is installed inside the oil tank 40, dividing the oil tank 40 into an upper chamber 42 and a lower chamber 43. The medium in the upper chamber 42 is air, and the medium in the lower chamber 43 is oil. The upper chamber 42 is connected to a vent plug 44 on the oil tank 40. A piston sealing ring 45 is installed on the outer ring of the movable piston 41. The above structure, as described above... Figure 6As shown, the lower end is the drive motor 28, and the upper end is the oil tank assembly. The drive motor 28 is a brushed DC motor, which drives the active gear shaft 4 through the drive shaft 39. The oil tank assembly includes a vent plug, an oil tank 40, a moving piston 41, and a piston sealing ring 45. The piston sealing ring 45 is installed in the sealing ring groove of the moving piston 41 as a piston assembly. The piston assembly is pressed into the oil tank. The vent plug is pressed into the top of the oil tank, and its function is to filter impurities such as dust, water vapor, and oil, except for air. The oil tank O-ring is installed into the sealing ring groove at the upper end of the pump housing. Finally, the entire oil tank is inserted into the upper end of the pump head assembly until the end face of the oil tank opening is pressed against the limiting step surface of the pump housing. The oil tank O-ring forms a seal between the oil tank and the pump housing 13 to prevent oil leakage and impurities from entering the oil tank. The piston assembly of the oil tank divides the oil tank into upper and lower chambers. The upper chamber 42 contains air, which is connected to the atmosphere through a vent plug at the top of the oil tank 40. The lower chamber 43 contains oil. When the pump operates and the oil in the lower chamber decreases, creating a negative pressure, the piston assembly will also move to the lower part of the oil tank 40, drawing in air to the upper chamber. When the oil tank returns oil, the oil pushes the piston assembly upward, expelling air from the upper chamber 42. The sealing and movement of the upper and lower chambers of the piston assembly depend on the low frictional resistance design of the piston seal ring 45.

[0026] In the structure of this invention, the pump housing and valve island of the gear pump are designed as a single unit. The flow channels and mounting cavities of all critical hydraulic valves (such as hydraulically controlled check valves, flow control valves, throttle valves, etc.) are integrated within this valve island, greatly reducing the need for external connecting pipelines.

[0027] As attached Figure 7-9 As shown, the pump head of the above-mentioned lifting power unit has its oil outlet and return ports directly connected to the oil pipe to the lower chamber of the lifting cylinder. The output of high-pressure oil and the return of load oil both pass through this port.

[0028] Hydraulic circuit connection: The first outlet on the right side of the gear pump is connected to the inlet of a check valve via an integrated flow channel. The outlet of the pilot-operated check valve is connected to the inlet of a flow control valve.

[0029] The function of this flow control valve is as follows: when the oil flows from the hydraulic check valve to the cylinder (forward), the flow resistance is minimal; when the oil flows back from the cylinder (reverse), it provides a stable throttling effect, thus limiting the flow. The outlet of the flow control valve is connected to the lower piston chamber of the lifting cylinder via a pipeline.

[0030] The second oil outlet on the left side of the gear pump is divided into two paths via an integrated flow channel: one path connects to the control port (push rod chamber) of a hydraulic check valve; the other path connects to the inlet of a throttle valve, with the outlet of the throttle valve returning to the oil tank. The function of this throttle valve is to establish the required pressure differential in the control oil circuit. The oil return path of the cylinder is: lower cylinder chamber → flow control valve (reverse throttling) → hydraulic check valve (already open) → oil inlet side of the gear pump (forming a circulation), while excess flow in the control oil circuit returns to the oil tank via the throttle valve.

[0031] The working principle and control method of the lifting unit described in this invention are as follows: Lifting Operation: The controller controls the motor to drive the gear pump to rotate forward. At this time, the first oil outlet is under high pressure, and the oil flows sequentially through the hydraulic check valve and the flow control valve (unobstructed in the forward direction) into the lower chamber of the cylinder, pushing the piston upward to achieve lifting. Lifting stops when the vehicle height sensor indicates that the lifting height has reached the preset height. The hydraulic check valve closes when there is no control pressure to prevent oil backflow.

[0032] Height holding condition: The control motor stops. The gear pump stops supplying oil, the system pressure is released, and the hydraulic check valve automatically closes under the pressure of its spring and the load, sealing the oil in the lower chamber of the cylinder, thereby reliably locking the load height.

[0033] Descent mode: The controller controls the motor to drive the gear pump in reverse. At this time, the second oil outlet is high pressure. The high-pressure oil first enters the push rod chamber of the hydraulic check valve, overcoming the spring force and the load pressure to push the valve core open. At the same time, under the action of the load gravity, the oil in the lower chamber of the cylinder is squeezed out, forming return oil. The return oil passes through the flow control valve (reverse throttling to achieve uniform descent) and the already opened hydraulic check valve, returning to the oil inlet side of the gear pump. In the control oil circuit, the throttle valve ensures that sufficient pressure is built up in the push rod chamber to open the hydraulic check valve. Excess high-pressure oil flows back to the oil tank through the throttle valve, playing a role in stabilizing pressure and diverting flow. When the vehicle height sensor reports that the descent height has reached the preset height, the descent stops. The hydraulic check valve closes when there is no control pressure to prevent oil backflow.

[0034] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any improvements made by adopting the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. A miniature gear pump, characterized in that: The irregular sealing ring (18) is located between the cover plate (5) and the floating bushing (2). The irregular sealing ring (18) and the cover plate (5) and the floating bushing (2) form a first compensation oil chamber (7) on one side. The irregular sealing ring (18) and the cover plate (5) and the floating bushing (2) form a second compensation oil chamber (12) on the other side. The first compensation oil chamber (7) is connected to the first oil inlet (14) with the first check valve (28) on the cover plate (5). The second compensation oil chamber (12) is connected to the second oil inlet (16) with the second check valve (47) on the cover plate (5). The first compensation oil chamber (7) is connected to the first oil chamber (6) of the gear pair. The first oil chamber (6) of the gear pair is connected to the first oil outlet (15). The second compensation oil chamber (12) is connected to the second oil chamber (11) of the gear pair. The second oil chamber (11) of the gear pair is connected to the second oil outlet (17).

2. The micro gear pump according to claim 1, characterized in that: When the driving gear shaft (1) drives the driving gear (4) to rotate clockwise, the first compensation oil chamber (7) of the floating bushing (2) on the first oil chamber (6) side of the gear pair forms a high pressure compensation area A (19), and the lower end face of the floating bushing (2) on the first oil chamber (6) side of the gear pair and the upper end face of the driving gear (4) and the driven gear (10) form an equivalent working area B (20); when the driving gear shaft (1) drives the driving gear (4) to rotate counterclockwise, the second compensation oil chamber (12) of the floating bushing (2) on the second oil chamber (11) side of the gear pair forms a high pressure compensation area A (19), and the lower end face of the floating bushing (2) on the second oil chamber (11) side of the gear pair and the upper end face of the driving gear (4) and the driven gear (10) form an equivalent working area B (20), and the oil working area of ​​the high pressure compensation area A (19) is greater than the oil working area of ​​the equivalent working area B (20).

3. The micro gear pump according to claim 1 or 2, characterized in that: The micro gear pump has a gear pair inside the pump housing (13). The gear pair includes a driving gear (4) and a driven gear (10). The driving gear (4) is connected to the driving gear shaft (1), and the driven gear (10) is connected to the driven gear shaft (8). The driving gear shaft (1) has an axial oil hole (21) inside, and the driven gear shaft (8) has an axial oil hole (22) inside.

4. The micro gear pump according to claim 1 or 2, characterized in that: A low-pressure lubricating oil chamber (46) is also formed between the irregular sealing ring (18), the cover plate (5), and the floating bushing (2). The low-pressure lubricating oil chamber (46) is connected to the axial oil hole (21) of the driving gear shaft through a through hole on the floating bushing (2), and the low-pressure lubricating oil chamber (46) is connected to the axial oil hole (22) of the driven gear shaft through another through hole on the floating bushing (2).

5. The miniature gear pump according to claim 1 or 2, characterized in that: When the drive gear shaft (1) extends into the first bushing hole (3), the drive gear shaft axial oil hole (21) is provided with a drive gear shaft radial oil hole (33) near the lower part. The drive gear shaft radial oil hole (33) connects the annular groove (34) between the drive gear shaft (1) and the first bushing hole (3) in the pump housing (13). When the driven gear shaft (8) extends into the second bushing hole (9), a gap is formed between the driven gear shaft (8) and the second bushing hole (9) of the pump housing (13). The driven gear shaft axial oil hole (22) connects to the gap.

6. The micro gear pump according to claim 4, characterized in that: The first oil inlet (14) and the second oil inlet (16) are respectively connected to the hydraulic oil tank (27), the low-pressure lubricating oil chamber (46) is connected to the hydraulic oil tank (27), and the upper end of the pump casing (13) is connected to the valve seat plate (25).

7. The miniature gear pump according to claim 1 or 2, characterized in that: The spring (29) at the lower end of the first check valve (28) is fitted into the positioning groove on the cover plate (5), and the valve core (30) at the upper end of the first check valve (28) rests against the positioning step of the first oil inlet (14). The spring (29) at the lower end of the second check valve (47) is fitted into the positioning groove on the cover plate (5), and the valve core (30) at the upper end of the second check valve (47) rests against the positioning step of the second oil inlet (16).

8. The micro gear pump according to claim 4, characterized in that: On the side of the drive gear shaft (1), a portion of the oil entering the axial oil hole (21) of the drive gear shaft from the low-pressure lubricating oil chamber (46) enters the first bushing hole oil groove (31) to lubricate the bushing friction pair formed by the floating bushing (2) of the upper part of the drive gear and the drive gear shaft (1). Another portion of the oil enters the annular groove (34) through the axial oil hole (21) and the radial oil hole (33) of the drive gear shaft to lubricate the bushing friction pair formed by the drive gear shaft (1) of the lower part of the drive gear (4) and the pump housing (13).

9. The micro gear pump according to claim 4, characterized in that: On the driven gear shaft (8) side, a portion of the oil entering the axial oil hole (22) of the driven gear shaft from the low-pressure lubricating oil chamber (46) enters the second bushing hole oil groove (32) through the gap, lubricating the bushing friction pair formed by the floating bushing (2) of the upper half of the driven gear shaft (8) and the driven gear shaft (8). Another portion of the oil enters the gap through the axial oil hole (22) of the driven gear shaft, lubricating the bushing friction pair formed by the driven gear shaft (8) of the lower half of the driven gear (10) and the pump housing (13).

10. A vehicle suspension lifting unit using the micro gear pump according to any one of claims 1 to 9, characterized in that: The micro gear pump is installed inside the pump housing (13). The drive gear shaft (1) is connected to the drive shaft (39) of the drive motor (38). An oil tank (40) is set at one end of the motor housing. A movable piston (41) is set inside the oil tank (40). The piston (41) divides the oil tank (40) into an upper chamber (42) and a lower chamber (43). The medium in the upper chamber (42) is air, and the medium in the lower chamber (43) is oil. The upper chamber (42) is connected to the vent plug (44) on the oil tank (40). A piston sealing ring (45) is set on the outer ring of the movable piston (41).

Images