Silent screw hydraulic oil pump

Abstract

The application discloses a mute screw hydraulic oil pump and belongs to the technical field of hydraulic oil pumps. The hydraulic oil pump is provided with a driving gear and a driven gear which are mutually engaged in the pump body. The driving gear and the driven gear are limitedly installed on the pump body through front and rear end covers. The driving gear and the driven gear are circular arc spiral gears. Guide mechanisms are arranged at the front and rear shaft ends of the pump body. The guide mechanism comprises a figure-eight ring which is floatingly arranged on the pump body. The shaft end portions of the driving gear and the driven gear are arranged in the through hole of the figure-eight ring through sealing bearings. High-pressure oil is introduced into the outside of the figure-eight ring at the oil outlet. The high-pressure oil is used for pushing the figure-eight ring to be compressed to the hydraulic chamber, so that the wear gap compensation of the driving gear, the driven gear and the figure-eight ring is realized.

Description

Technical Field

[0001] This invention relates to the field of hydraulic pump technology, and specifically to a silent screw hydraulic pump. Background Technology

[0002] As the core power component of a hydraulic transmission system, the hydraulic oil pump converts the mechanical energy output by the prime mover into hydraulic energy, providing stable pressure oil to the system. It is widely used in many fields such as machinery manufacturing, automobile manufacturing, aerospace, petrochemicals, and new energy.

[0003] In existing screw hydraulic pumps, the gear transmission structure also uses an involute helical gear design. This design has two major technical defects that make it difficult to meet the requirements of high-end applications: First, the meshing clearance of the involute helical gear changes dynamically during the transmission process, which easily leads to oil trapping. The oil in the trapped area is squeezed or cavitated, which not only causes obvious pulsating noise but also causes fluctuations in the pump output pressure, reducing the smoothness of the hydraulic system. Its operating noise is usually far higher than the 60-decibel quiet requirement of high-end applications. Second, the involute helical gear transmission process generates continuous axial force. The axial forces of the driving gear and the driven gear are in opposite directions, and long-term frictional wear occurs between the gear and the pump body and guide components. As the usage time increases, the wear clearance between the gear and the mating parts continues to increase, directly causing a significant decrease in the volumetric efficiency of the pump. At the same time, the metal debris generated by wear also affects the cleanliness of the hydraulic oil, further reducing the service life and operational reliability of the pump.

[0004] To address these issues, the industry has attempted to improve the situation by optimizing gear machining precision and replacing materials with wear-resistant ones. However, these methods only alleviate wear problems in the short term and cannot fundamentally eliminate the oil trapping noise caused by involute helical gear meshing. Furthermore, they are insufficient to meet the compensation requirements of different axial forces on the driving and driven gears, and the problem of increased wear clearance over time persists. Therefore, developing a silent screw hydraulic pump that can structurally eliminate oil trapping, achieve precise compensation for different axial forces, and maintain high volumetric efficiency over the long term has become an important research direction in the field of hydraulic pump technology and is crucial to meeting the development needs of the high-end equipment manufacturing industry. Summary of the Invention

[0005] Purpose of the invention: In view of the problems mentioned in the background art, the present invention aims to provide a silent screw oil pump, which solves the problems mentioned in the background art such as noise caused by oil trapped in the gear meshing clearance and the serious wear caused by the axial force between the gear and the pump body, resulting in a decrease in the volumetric efficiency of the oil pump.

[0006] Technical solution: A silent screw hydraulic oil pump includes a pump body, a hydraulic chamber inside the pump body with an oil inlet and an oil outlet, and a driving gear and a driven gear that mesh with each other are provided in the hydraulic chamber. The driving gear and the driven gear are limited and installed in the pump body through a front end cover and a rear end cover. The driving gear and the driven gear are circular arc helical gears. Guide mechanisms are provided at both the front and rear shaft ends of the pump body. The guiding mechanism includes a figure-eight ring floating on the pump body. The shaft ends of the driving gear and the driven gear are set in the through hole of the figure-eight ring through sealed bearings. A closed chamber is constructed on the outside of the figure-eight ring to allow high-pressure oil to be introduced into the oil outlet. The high-pressure oil is used to push the figure-eight ring to press against the hydraulic chamber, thereby compensating for the wear clearance of the driving gear, the driven gear, and the figure-eight ring.

[0007] Furthermore, the guiding mechanism forms a side high-pressure chamber on the inner side of the front cover and the outer end face of the figure-eight ring through a semi-enclosed curved ring, and the side high-pressure chamber introduces high-pressure oil from the oil outlet side through a high-pressure channel. The high-pressure channel is formed by the gap reserved between the waistline on both sides of the figure-eight ring and the inner wall of the pump body.

[0008] Furthermore, a compensation piston is provided at the shaft end of the drive gear, and an oil outlet is connected to the oil passage behind the compensation piston to introduce high-pressure oil into the side high-pressure chamber. The high-pressure oil in the side high-pressure chamber can drive the drive gear to move axially to balance the axial force of the gear.

[0009] Furthermore, the figure-eight ring is a split structure to cope with the different axial forces of the driving gear and the driven gear, including sections respectively sleeved on the shafts of the driving gear and the driven gear. The mirror surfaces set on the two sections can fit tightly together, and the figure-eight ring forms a symmetrical structure along the fitted mirror surfaces.

[0010] Furthermore, both the front end cover and the rear end cover are provided with sealing rings on the connection surface with the pump body, and a curved ring is provided inside the sealing ring to form a seal for the side high-pressure chamber.

[0011] Furthermore, the shaft end of the drive gear passes through the front end cover via a sealed bearing and is used to connect with the drive motor to achieve rotation control.

[0012] The front and rear covers are provided with circular slots around the drive gear shaft, and retaining rings are provided in the slots to limit the position of the gear end.

[0013] The front end cover and the rear end cover include mounting grooves and mounting positions on their inner side walls, which are provided with sealing rings, curved rings, and limiting rings.

[0014] Beneficial effects: Compared with the prior art, the driving gear and driven gear in the silent screw hydraulic oil pump provided by this invention are improved from the original involute helical gear transmission by adopting circular arc helical gears. This avoids oil trapping caused by changes in the meshing clearance between the two gears, thus preventing noise. After adopting this measure, the oil pump noise is reduced to below 60 decibels. Secondly, because circular arc helical gears are used for meshing, there is no meshing clearance between the two gears, so there is no oil trapping phenomenon, which greatly reduces the output pulsation of the oil pump and greatly increases the self-priming force of the oil pump. Thirdly, the guide mechanism of the oil pump adopts a floating figure-eight ring. High-pressure oil from the oil pump outlet is introduced into both ends of the figure-eight ring, pushing the figure-eight ring to press against the gear, compensating for the wear of the gear and the figure-eight ring. This solves the technical problem that when the helical gear pump is working, the gears will generate axial force, and the two gears have opposite axial forces, requiring different compensating clamping forces. Fourth, the figure-eight ring adopts a split design to cope with different axial forces. A compensation piston is designed at the shaft end of the drive gear. The oil passage behind the piston is connected to the oil pump outlet, and high-pressure oil is introduced to push the compensation piston to push the drive gear to balance the axial force of the gear and reduce wear. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall assembly structure of the present invention; Figure 2 This is a schematic diagram of the internal structure of the guide mechanism (with the front cover removed). Figure 3 This is an exploded view of the structure of the present invention; Figure 4 This is a schematic diagram of the meshing structure of the driving gear and the driven gear; Figure 5 This is the main view of the circular arc helical gear structure; Figure 6 This is a structural diagram of a figure-eight ring; Figure 7 This is an installation diagram showing the figure-eight ring placed inside the pump body; Figure 8 This is a structural diagram of the adapter sealing assembly on the front cover; Figure 9 This is a schematic diagram of the installation of the compensation piston at the rear end cover.

[0016] In the diagram: 1. Pump body; 2. Front cover; 3. Drive gear; 4. Driven gear; 5. Oil inlet; 6. Oil outlet; 7. Rear cover; 8. Bolt; 9. Figure-eight ring; 10. Compensating piston; 11. High-pressure channel; 201. Sealing ring; 202. Crank ring; 203. Limiting ring; 204. Oil seal; 205. Clamp. Detailed Implementation

[0017] To illustrate the technical solution provided by this invention in detail, further description is provided below with reference to the accompanying drawings.

[0018] The silent screw hydraulic oil pump provided by this invention is described in [reference]. Figure 1-7 As shown.

[0019] Combination Figure 3 The provided exploded view shows that the hydraulic pump of the present invention includes a pump body 1. The pump body 1 has internal chambers for a driving gear 3 and a driven gear 4. Both sides of the pump body 1 have a structure that can accommodate a figure-eight ring 9. The structure of the figure-eight ring 9 is as follows... Figure 6 As shown. The pump body 1 has an oil inlet 5 and an oil outlet 6. Hydraulic oil enters the chamber through the oil inlet 5, and then, through the meshing motion of the gear set, the hydraulic oil is discharged from the oil outlet 6. See the diagram for the circular arc helical gear structure. Figure 4 and Figure 5 As shown, both the front cover 2 and the rear cover 7 are fixed to the pump body 1 by bolts 8.

[0020] This invention provides guide mechanisms on both sides of the pump body 1. The guide mechanism refers to the assembly between the outer end face of the pump body 1 and the front cover 2 or rear cover 7, including a floating figure-eight ring 9. Both ends of the driving gear 3 and driven gear 4 are placed in the shaft hole of the figure-eight ring 9 through inner sliding sleeves. The inner end face of the figure-eight ring 9 is in contact with the gear portion of the driving gear 3 or driven gear 4. After being placed inside the pump body 1, its outer side is flush with the cross-section of the pump body 1, allowing it to participate in… Figure 7 As shown, Figure 7 It is the structure after the rear cover 7 has been removed, and does not include the sealing components. Figure 2 The sealing structure of the guide mechanism and the front cover 2 or the rear cover 7 is shown, combined with Figure 3 It can be seen that at the end of the driving gear 3 or driven gear 4, a sealing ring 201 is fitted to the end cover to form an integral seal. Within the encirclement formed by the sealing ring 201, a curved ring 203 separates the high-pressure side chamber and the low-pressure side chamber. The curved ring 203 is a closed-loop component, but the whole forms a semi-enclosed structure on the outer wall of the pump body 1. The high-pressure chamber and the low-pressure side chamber correspond to the figure-eight ring 9 on the oil inlet 5 and oil outlet 6 sides, respectively, and oil channels are set accordingly. The high-pressure side chamber introduces high-pressure oil from the oil outlet 6 side through the high-pressure channel 11. The high-pressure side chamber includes two parts of the figure-eight ring 9, and the pump body 1 is pressed tightly within the two parts of the figure-eight ring 9 by the high-pressure oil. The end fixing of the driving gear 3 or driven gear 4 is achieved by the limiting ring 203 and the clamp 205. Correspondingly, Figure 8 The groove or mounting position on the inner side of the front cover 2 that adapts to the sealing assembly is shown. It is worth noting that the side high-pressure chamber and the side low-pressure chamber are formed based on the thickness of the sealing ring 201 and the curved ring 202.

[0021] The shaft of the drive gear 3 extends through the front cover 2 via the oil seal 205 and is used to connect to rotating equipment, including the motor, to control its rotation. The rotation of the drive gear 3 drives the driven gear 4 to rotate in the opposite direction. The gradual meshing between the two enables the low-pressure oil on the oil inlet 5 side to be output at high speed to the oil outlet 6.

[0022] Additionally, for the shaft end of the drive gear 3, such as Figure 9 As shown, on the side where the rear cover 7 is located, the present invention provides a compensation piston 10. The compensation piston 10 is fixed to the end of the rotating shaft. Its purpose is to use the high-pressure oil in the side high-pressure chamber to drive the drive gear 3 axially, thereby compensating for the gap after the wear of the figure-eight ring 9 and the gear. To achieve this purpose, the edge of the compensation piston 10 does not extend beyond the portion of the figure-eight ring 9, that is, it is not obstructed by the end side wall of the pump body 1, and can slightly push the figure-eight ring 9 into the double-arched cross-section of the pump body 1. Furthermore, the compensation piston 10 is designed to increase the contact area between the end of the drive gear 3 shaft and the high-pressure oil, thereby balancing the axial force of the gear. It should be noted that the rotating shaft of the drive gear 3, which passes through the front cover 2, is connected to the motor for rotation, and therefore is not considered for compensation.

[0023] Further reference Figure 2 , 3 6 and Figure 7 The front cover 2 is fixedly connected to the pump body 1 by bolts 8 in the screw holes, and the sealing ring 201 serves as a seal. The drive gear 3 has a sealed bearing on the contact surface of the front cover 2 for sealing and rotation functions. The sealed bearing is fixedly connected to the front cover 2 via the side wall or outer circumference to achieve sealing. An arc-shaped groove is provided in the through hole of the drive gear 3 shaft in the front cover 2, and a retaining ring is installed in the groove for limiting, sealing, blocking, and connecting the drive rod of the motor. The figure-eight ring 9 can undergo slight sliding under the push of high-pressure oil to compensate for and counteract the axial force of the arc-shaped helical gear and the wear of other components. The oil leakage between the figure-eight ring 9 and the side wall of the pump body 1 is small, and its impact on the different pressure chambers formed by the gear set inside the pump body 1 is negligible. Under the action of the limiting ring 203 on the side wall of the front cover 2, the curved ring 202 can be fixed on the side wall of the figure-eight ring 9, and high-pressure oil is introduced through the channel formed between the waistline of the figure-eight ring 9 and the pump body 1. The curved ring 202 isolates the low-pressure chamber side, and the outer side is located on the side wall of the pump body 1. The inner side is squeezed and elastically fixed around the rotating shaft on the figure-eight ring 9. The closed cavity includes three-quarters of the area of ​​the figure-eight ring 9 to improve the oil pressure to compensate for the thrust.

[0024] The shafts of the driving gear 3 and the driven gear 4 are chamfered at the connection points with the gears, so the gap between the figure-eight ring 9 and the gear sidewall does not affect the rotation of the gears.

[0025] In other embodiments, a rotating hole for a compensating piston 10 is provided on the inner wall of the rear end cover 7, and hydraulic oil is introduced into the hole for lubrication. Two cylindrical compensating pistons 10 are provided inside the rear end cover 7. The compensating pistons 10 abut against the rotating shafts of the driving gear 3 and the driven gear 4. The compensating pistons 10 can also exert a thrust on the rotating shaft of the driving gear 3 by means of a spring or by combining high-pressure oil.

[0026] Functional Principle: The driving gear 3 and driven gear 4 of this invention are improved upon by adopting circular arc helical gears based on the existing involute helical gear transmission of oil pumps. This avoids oil trapping caused by changes in the meshing clearance between the two gears, thus preventing noise. After adopting this measure, the oil pump noise is reduced to below 60 decibels. Because of the use of gradually changing circular arc helical gear meshing, there is no meshing clearance between the two gears, so there is no oil trapping phenomenon, which greatly reduces the output pulsation of the oil pump and greatly increases the self-priming force of the oil pump.

[0027] To prevent the oil pump's volumetric efficiency from decreasing due to frictional wear between the gear set and pump body 1, the pump's guiding mechanism employs a floating figure-eight ring 9. High-pressure oil from the pump outlet is introduced to both ends of the figure-eight ring 9, pushing it to press against the gears, thus compensating for wear on both the gears and the figure-eight ring 9 within a certain wear range. When the helical gear pump is operating, the gears generate axial forces, and the axial forces of the two gears are opposite. The required compensating clamping forces for the two gears are different, so the figure-eight ring 9 adopts a split design. To cope with different axial forces, a compensating piston 10 is designed at the shaft end of the drive gear. An oil passage behind the compensating piston 10 connects to the pump outlet, introducing high-pressure oil to push the compensating piston 10 and drive the drive gear 3 to balance the axial force of the gears and reduce wear.

Claims

1. A silent screw hydraulic oil pump, comprising a pump body (1), wherein a hydraulic chamber within the pump body (1) has an oil inlet (5) and an oil outlet (6), and wherein a driving gear (3) and a driven gear (4) meshing with each other are provided within the hydraulic chamber, wherein the driving gear (3) and the driven gear (4) are limited and installed within the pump body (1) by a front end cover (2) and a rear end cover (7), characterized in that, The driving gear (3) and driven gear (4) are circular arc helical gears, and guide mechanisms are provided at both the front and rear shaft ends of the pump body (1). The guiding mechanism includes a figure-eight ring (9) floating on the pump body (1). The shaft ends of the driving gear (3) and driven gear (4) are set in the through hole of the figure-eight ring (9) through sealed bearings. The outer side of the figure-eight ring (9) is constructed with a sealed chamber to enable the introduction of high-pressure oil at the oil outlet (6). The high-pressure oil is used to push the figure-eight ring (9) to press against the hydraulic chamber, thereby compensating for the wear gap of the driving gear (3), driven gear (4), and figure-eight ring (9).

2. The silent screw hydraulic pump according to claim 1, characterized in that, The guiding mechanism forms a side high-pressure chamber on the inner side of the front cover (2) and the outer end face of the figure-eight ring (9) through a semi-enclosed curved ring (202). The side high-pressure chamber introduces high-pressure oil from the oil outlet (6) through the high-pressure channel (11). The high-pressure channel (11) is formed by the gap reserved between the waistline on both sides of the figure-eight ring (9) and the inner wall of the middle part of the pump body (1).

3. The silent screw hydraulic pump according to claim 1 or 2, characterized in that, The shaft end of the drive gear (3) is provided with a compensation piston (10). The oil passage behind the compensation piston (10) is connected to the oil outlet (6) to realize the introduction of high pressure oil into the side high pressure chamber. The high pressure oil in the side high pressure chamber can drive the drive gear (3) to axially displace in order to balance the axial force of the gear.

4. The silent screw hydraulic pump according to claim 1, characterized in that, The figure-eight ring (9) is a split structure to cope with the different axial forces of the driving gear (3) and the driven gear (4). It includes sections respectively sleeved on the shafts of the driving gear (3) and the driven gear (4). The mirrors set on the two sections can fit tightly together, and the figure-eight ring (9) forms a symmetrical structure along the fitted mirrors.

5. The silent screw hydraulic pump according to claim 1, characterized in that, Both the front cover (2) and the rear cover (7) are provided with sealing rings (201) on the connection surface with the pump body (1). A curved ring (202) is provided inside the sealing ring (201), and a sealed side high-pressure chamber is formed through the curved ring (202).

6. The silent screw hydraulic pump according to claim 1, characterized in that, The shaft end of the drive gear (3) passes through the front end cover (2) via a sealed bearing and is used to connect with the drive motor to achieve rotation control.

7. The silent screw hydraulic pump according to claim 1, characterized in that, The front cover (2) and the rear cover (7) are provided with circular slots around the shaft of the drive gear (3), and a retaining ring is provided in the slot to limit the end of the gear.

8. The silent screw hydraulic pump according to claim 1, characterized in that, The front cover (2) and the rear cover (7) include mounting grooves and mounting positions on their inner sidewalls for a sealing ring (201), a curved ring (202), and a limiting ring (203).

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