Bidirectional high-pressure high-speed axial plunger pump with self-suction function

Abstract

The utility model discloses a two-way high-pressure high-speed axial plunger pump with a self-suction function. The two-way high-pressure high-speed axial plunger pump comprises an external valve block, a front cover, a rear shell and a transmission shaft. According to the plunger pump, the innovative design that the non-Newtonian fluid forms a solid isolation layer under the high-speed working condition is adopted, the technical problem that abrasion of a return stroke mechanism is aggravated when the rotating speed of a traditional plunger pump exceeds 4500 rpm is effectively solved, and the service life under the high-pressure and high-speed working condition is remarkably prolonged; by optimizing the coating structures of the return balls and the ball grooves and the sealing fit of the PTFE lip-shaped sealing rings, the problem of lubrication failure caused by fluid permeation in the two-way working process is solved, and more stable power transmission performance under the two-way high-pressure working condition is achieved.

Description

A self-priming bidirectional high-pressure high-speed axial piston pump Technical Field

[0001] This utility model relates to the field of hydraulic technology, and in particular to a bidirectional high-pressure high-speed axial piston pump with self-priming function. Background Technology

[0002] A piston pump is an important component of a hydraulic system. It achieves oil suction and pressure by the reciprocating motion of a piston within a cylinder, which changes the volume of the sealed working chamber. Piston pumps offer advantages such as high rated pressure, compact structure, high efficiency, and convenient flow rate adjustment. They are widely used in high-pressure, high-flow-rate applications where flow rate regulation is required, such as hydraulic presses, construction machinery, and ships.

[0003] Existing bidirectional high-pressure high-speed axial piston pumps all use a front housing plus a rear cover, combined with pipe fittings and oil pipes. This type of structure not only increases the size of the parts, but also makes the pipe fittings and oil pipes prone to oil leakage. Such products are suitable for mass-market industrial products. In some applications with high integration requirements, the piping connections will significantly increase the size and weight. At the same time, because the pipe fittings need to be connected to the oil port through external threads, the effective flow area of ​​the oil port is greatly reduced, thus limiting the flow rate of the piston pump, especially in small and micro hydraulic piston pumps.

[0004] To reduce weight and size, making the entire system more concise and compact, and facilitating installation and disassembly, a publicly disclosed technology proposes a bidirectional plunger pump with an axial oil port. This pump includes a drive shaft, a front cover, and a rear housing. The drive shaft is supported at both ends by bearings in the front cover and rear housing, respectively. A cylinder block is splined to the middle of the drive shaft and mounted on it. The cylinder block has an oil passage and a plunger cavity. A plunger pair is installed in the plunger cavity. A return ball is splined onto the drive shaft, and the return ball abuts against a return disc. The return disc presses the plunger pair against a swashplate. The return ball is connected to a support pin. A cylinder spring connects the pin to the cylinder body. The bidirectional piston pump mentioned in this disclosure does not require pipe joint connections, reducing weight and volume, and making installation and disassembly convenient. However, when the speed exceeds 4500 rpm, the traditional steel return mechanism of the above-mentioned technology faces severe wear challenges: firstly, the failure of lubrication at the boundary of the ball-disc contact area leads to a sharp increase in the wear rate; secondly, the existing technology using hard alloy coating can only improve the PV value tolerance to a limited extent, which is still difficult to meet the requirements of electro-hydraulic systems for high-speed operation. It is necessary to further optimize and improve its structure. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing a bidirectional high-pressure high-speed axial piston pump with self-priming function.

[0006] To achieve the above objectives, this utility model adopts the following technical solution: a bidirectional high-pressure high-speed axial piston pump with self-priming function, comprising an external valve block, a front cover, a rear housing, and a drive shaft. The external valve block, front cover, and rear housing are sequentially connected in a left-right arrangement. The two ends of the drive shaft are supported by bearings in the front cover and the rear housing, respectively. A swashplate is fixedly connected to the inner right wall of the rear housing. Multiple sets of cylinders are arranged on the inner wall of the rear housing and around the drive shaft. A piston pair is slidably connected to the inner wall of each set of cylinders. A return ball is fixedly connected to the right end of each piston pair. A return disc is rotatably connected to the outer wall of the drive shaft and between the cylinder and the swashplate. Multiple sets of ball grooves adapted to the return ball are arranged on the side of the return disc away from the swashplate. A non-Newtonian fluid is arranged between the inner wall of the ball groove and the outer wall of the return ball. The non-Newtonian fluid forms a solid isolation layer when the drive shaft speed is >4500 rpm. The non-Newtonian fluid has a shear rate >5×10 4 s -1 When the viscosity rises to 10 3 Pa·s, a seal is provided between the ball groove and the return ball.

[0007] As a further description of the above technical solution:

[0008] A sealing groove is provided on the inner side wall of the ball groove at the end away from the swash plate. The sealing element is provided on the inner side wall of the sealing groove, and the inner side wall of the sealing element is slidably connected to the outer wall of the return ball.

[0009] As a further description of the above technical solution:

[0010] The sealing element is a PTFE lip seal ring, the lip inclination angle of the sealing element is 45±5°, and the compression ratio is controlled at 15-20%.

[0011] As a further description of the above technical solution:

[0012] The inner wall of the ball groove is provided with a second coating to prevent the penetration of non-Newtonian fluids, and the thickness of the second coating is 20-50 μm.

[0013] As a further description of the above technical solution:

[0014] The second coating is aluminum oxide, and the second coating is anodized, with a surface hardness ≥1500HV.

[0015] As a further description of the above technical solution:

[0016] The return ball comprises a substrate, a bonding layer, and a first coating layer arranged sequentially from the inside out, wherein the thickness of the first coating layer is 3-5 μm.

[0017] As a further description of the above technical solution:

[0018] The substrate is a nickel-based high-temperature alloy, the bonding layer is a CrN ion plating layer, and the first coating is a diamond-like carbon film.

[0019] This utility model has the following beneficial effects:

[0020] 1. Compared with existing technologies, this self-priming bidirectional high-pressure high-speed axial piston pump effectively solves the technical problem of increased wear of the return mechanism in traditional piston pumps when the speed exceeds 4500 rpm by adopting an innovative design that uses non-Newtonian fluid to form a solid isolation layer under high-speed conditions, and significantly improves the service life under high-pressure and high-speed conditions.

[0021] 2. Compared with existing technologies, this self-priming bidirectional high-pressure high-speed axial piston pump overcomes the lubrication failure problem caused by fluid penetration during bidirectional operation by optimizing the coating structure of the return ball and ball groove and the sealing fit of the PTFE lip seal ring, thus achieving more stable power transmission performance under bidirectional high-pressure conditions. Attached Figure Description

[0022] Figure 1 is a schematic diagram of the overall structure of a bidirectional high-pressure high-speed axial piston pump with self-priming function proposed in this utility model.

[0023] Figure 2 is a partial cross-sectional view of the internal structure of the rear housing of a bidirectional high-pressure high-speed axial piston pump with self-priming function proposed in this utility model.

[0024] Figure 3 is a partial enlarged view of point A in Figure 2 of a bidirectional high-pressure high-speed axial piston pump with self-priming function proposed in this utility model.

[0025] Figure 4 is a cross-sectional view of the return ball structure of a bidirectional high-pressure high-speed axial piston pump with self-priming function proposed in this utility model.

[0026] Legend:

[0027] 1. Drive shaft; 2. Front cover; 3. Rear housing; 4. External valve block; 5. Cylinder block; 6. Plunger pair; 7. Return ball; 701. Base; 702. Bonding layer; 703. First coating layer; 8. Return disc; 801. Ball groove; 8011. Sealing groove; 802. Second coating layer; 9. Swash plate; 10. Seal; 11. Non-Newtonian fluid. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0029] Referring to Figures 1 to 4, this utility model provides a bidirectional high-pressure high-speed axial piston pump with self-priming function: including an external valve block 4, a front cover 2, a rear housing 3, and a drive shaft 1. The external valve block 4, the front cover 2, and the rear housing 3 are connected sequentially in a left-right arrangement. The two ends of the drive shaft 1 are supported by bearings in the front cover 2 and the rear housing 3, respectively. A swash plate 9 is fixedly connected to the inner right wall of the rear housing 3. Multiple sets of cylinders 5 are arranged on the inner wall of the rear housing 3 and around the drive shaft 1. A piston pair 6 is slidably connected to the inner wall of each set of cylinders 5. A return ball 7 is fixedly connected to the right end of the piston pair 6. A return plate 8 is rotatably connected to the outer wall of the drive shaft 1 between the cylinder 5 and the swash plate 9.

[0030] To achieve dynamic lubrication protection under high-speed operating conditions, the return plate 8 is provided with multiple sets of ball grooves 801 adapted to the return ball 7 on the side away from the swashplate 9. A non-Newtonian fluid 11 is provided between the inner wall of the ball groove 801 and the outer wall of the return ball 7. The non-Newtonian fluid 11 forms a solid isolation layer when the speed of the drive shaft 1 is >4500 rpm. The non-Newtonian fluid 11 forms a solid isolation layer when the shear rate is >5×10⁻⁶ rpm. 4 s -1 When the viscosity rises to 10 3 Pa·s;

[0031] When the plunger pump is running at high speed, the non-Newtonian fluid 11 can automatically adjust its viscosity according to the speed change, forming a solid lubricating layer above the critical speed, effectively preventing wear caused by direct metal-metal contact.

[0032] To address the sealing issue during bidirectional operation, a seal 10 is provided between the ball groove 801 and the return ball 7. A sealing groove 8011 is provided on the inner wall of the ball groove 801 at the end furthest from the swashplate 9. The seal 10 is located on the inner wall of the sealing groove 8011, and the inner wall of the seal 10 is slidably connected to the outer wall of the return ball 7. The seal 10 is a PTFE lip seal ring with a lip inclination angle of 45±5° and a compression ratio controlled at 15-20%.

[0033] PTFE lip seals can maintain stable sealing contact pressure under bidirectional pressure, preventing leakage of non-Newtonian fluids and blocking the entry of external contaminants.

[0034] To enhance the wear resistance and anti-permeability of the ball groove 801, a second coating 802 is provided on the inner wall of the ball groove 801 to prevent the penetration of non-Newtonian fluid 11. The thickness of the second coating (802) is 20-50μm. The second coating 802 is aluminum oxide and is anodized, with a surface hardness ≥1500HV.

[0035] The alumina coating not only provides an excellent wear-resistant surface, but its dense structure can also effectively prevent the penetration and diffusion of non-Newtonian fluids.

[0036] To improve the overall performance of the return ball 7, the return ball 7 includes a substrate 701, a bonding layer 702 and a first coating 703 arranged sequentially from the inside to the outside. The thickness of the first coating 703 is 3-5 μm. The substrate 701 is a nickel-based high-temperature alloy, the bonding layer 702 is a CrN ion plating layer, and the first coating 703 is a diamond-like carbon film.

[0037] The multi-layer composite design of the return ball 7 maintains the strength of the substrate 701 while the surface coating significantly reduces the coefficient of friction and improves corrosion resistance.

[0038] Working principle: When the plunger pump is running at high speed, the non-Newtonian fluid 11 can automatically adjust its viscosity according to the speed change, forming a solid lubricating layer above the critical speed, effectively preventing wear caused by direct metal-to-metal contact; the PTFE lip seal can maintain a stable sealing contact pressure under bidirectional pressure, preventing leakage of the non-Newtonian fluid 11 and blocking the entry of external contaminants; the alumina coating not only provides an excellent wear-resistant surface, but its dense structure can also effectively prevent the penetration and diffusion of the non-Newtonian fluid 11; the multi-layer composite design of the return ball 7 maintains the strength of the substrate 701 while the surface coating significantly reduces the coefficient of friction and improves corrosion resistance.

[0039] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A bidirectional high-pressure high-speed axial piston pump with self-priming function, characterized in that: The system includes an external valve block (4), a front cover (2), a rear housing (3), and a drive shaft (1). The external valve block (4), the front cover (2), and the rear housing (3) are connected sequentially in a left-right arrangement. The two ends of the drive shaft (1) are supported by bearings in the front cover (2) and the rear housing (3), respectively. A swashplate (9) is fixedly connected to the right inner wall of the rear housing (3). Multiple sets of cylinders (5) are arranged on the inner wall of the rear housing (3) and around the drive shaft (1). A plunger pair (6) is slidably connected to the inner wall of each set of cylinders (5). The plunger pair (6) is located on the right side of the drive shaft (1). A return ball (7) is fixedly connected to the end of the drive shaft (1). A return disc (8) is rotatably connected to the outer wall of the drive shaft (1) between the cylinder (5) and the swashplate (9). Multiple sets of ball grooves (801) adapted to the return ball (7) are provided on the side of the return disc (8) away from the swashplate (9). A non-Newtonian fluid (11) is provided between the inner wall of the ball groove (801) and the outer wall of the return ball (7). The non-Newtonian fluid (11) forms a solid isolation layer when the speed of the drive shaft (1) is >4500 rpm. The non-Newtonian fluid (11) forms a solid isolation layer when the shear rate is >5×10⁻⁶ rpm. 4 s -1 When the viscosity rises to 10 3 Pa·s, a seal (10) is provided between the ball groove (801) and the return ball (7).

2. The bidirectional high-pressure high-speed axial piston pump with self-priming function according to claim 1, characterized in that: A sealing groove (8011) is provided on the inner side wall of the ball groove (801) at the end away from the swash plate (9), and the sealing element (10) is provided on the inner side wall of the sealing groove (8011). The inner side wall of the sealing element (10) is slidably connected to the outer wall of the return ball (7).

3. A bidirectional high-pressure high-speed axial piston pump with self-priming function according to claim 2, characterized in that: The sealing element (10) is a PTFE lip seal ring, the lip inclination angle of the sealing element (10) is 45±5°, and the compression ratio is controlled at 15-20%.

4. A bidirectional high-pressure high-speed axial piston pump with self-priming function according to claim 1, characterized in that: The inner wall of the ball groove (801) is provided with a second coating (802) to prevent the penetration of non-Newtonian fluid (11), and the thickness of the second coating (802) is 20-50 μm.

5. A bidirectional high-pressure high-speed axial piston pump with self-priming function according to claim 4, characterized in that: The second coating (802) is aluminum oxide, and the second coating (802) is anodized and has a surface hardness ≥1500HV.

6. A bidirectional high-pressure high-speed axial piston pump with self-priming function according to claim 1, characterized in that: The return ball (7) includes a substrate (701), a bonding layer (702), and a first coating layer (703) arranged sequentially from the inside to the outside, with the thickness of the first coating layer (703) being 3-5 μm.

7. A bidirectional high-pressure high-speed axial piston pump with self-priming function according to claim 6, characterized in that: The substrate (701) is a nickel-based high-temperature alloy, the bonding layer (702) is a CrN ion plating layer, and the first coating layer (703) is a diamond-like carbon film.

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