A free-plunger hydraulic pump without lateral force

Abstract

A free-plunger hydraulic pump without lateral force includes a swashplate and an upper sliding plate. The swashplate is mounted on one end of the main shaft located within the pump body cavity, and the swashplate axis does not coincide with the main shaft axis. A counterweight is provided on the outer circumference of the swashplate away from its eccentric portion to align the swashplate's center of mass with the main shaft axis. One end of the swashplate corresponding to the pump body's closed end is a straight surface and slides in contact with the closed end of the pump body. This end of the swashplate has an oil discharge chamber communicating with the outlet. The other end of the swashplate is an inclined surface, and the length of one side of the eccentric portion is greater than the length of the other side. The inclined end of the swashplate has a high-pressure oil chamber communicating with the oil discharge chamber, and the axis of the high-pressure oil chamber coincides with the swashplate axis. In this invention, the swashplate's center of mass is located on the swashplate's rotation axis, eliminating the centrifugal force of the swashplate rotation. The two ends of the plunger assembly are connected by a ball joint, eliminating lateral force and resulting in better force distribution, enabling higher speed operation.

Description

Technical Field

[0001] This invention relates to the field of piston pump technology, and in particular to a free piston hydraulic pump without lateral force. Background Technology

[0002] As is well known, piston pumps are the main devices in hydraulic systems that achieve high-pressure output. They have high output pressure and can maintain high volumetric efficiency and overall efficiency even under high pressure. In traditional piston pumps, the drive shaft drives the rotor assembly to rotate, and a swashplate at a fixed angle drives the pistons in the piston holes on the rotor to reciprocate, completing the oil suction and discharge process. However, traditional piston pumps have some shortcomings, such as:

[0003] 1. During operation, the rotor is subjected to overturning torque due to the lateral force of the plunger, resulting in complex stress on the rotor body; 2. Under high-speed rotation conditions, the moment of inertia is large and there is a large unstable centrifugal force; 3. Under high-speed rotation conditions, the plunger will have excessive speed and acceleration, resulting in poor stability; 4. There are many friction pairs inside the pump, with high relative speed and low reliability. The above defects are problems that urgently need to be solved by those skilled in the art. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, the present invention discloses a free piston hydraulic pump without lateral force.

[0005] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0006] A free-plunger hydraulic pump without lateral force includes a pump body and an end cover. The pump body has a cavity and one end is open. An end cover is installed at the open end. The end cover is rotatably connected to a main shaft that extends into the cavity of the pump body. The closed end of the pump body has an outlet and an inlet is provided on the side corresponding to the outlet.

[0007] It also includes a swashplate and an upper sliding plate; the swashplate is installed at one end of the main shaft located in the pump body cavity, and the axis of the swashplate does not coincide with the axis of the main shaft. A counterweight is provided on the side of the outer circle of the swashplate away from its eccentric part to make the center of mass of the swashplate coincide with the axis of the main shaft. The end of the swashplate corresponding to the closed end of the pump body is a flat surface and slides in contact with the closed end of the pump body. This end of the swashplate is provided with an oil discharge chamber that communicates with the liquid outlet. The other end of the swashplate is an inclined surface, and the length of one side of the eccentric part of the swashplate is greater than the length of the other side. The inclined end of the swashplate is provided with a high-pressure oil chamber that communicates with the oil discharge chamber. The high-pressure oil chamber is an annular groove, and the axis of the high-pressure oil chamber coincides with the axis of the swashplate.

[0008] The inclined end of the swashplate is slidably fitted with an upper sliding plate that is movably sleeved with the main shaft; the inner side of the end cover is provided with an annular boss that is movably sleeved with the main shaft, and the upper sliding plate is universally fitted with the annular boss; multiple hollow plungers are arranged circumferentially between the upper sliding plate and the end cover, and the plungers are movably inserted into the upper sliding plate and the end cover; the upper sliding plate is provided with oil passage holes corresponding to the plunger positions, which are connected to the plunger cavities, and the oil passage holes can be connected to the high-pressure oil chamber during the rotation of the swashplate, and are exposed on the side of the swashplate with the counterweight as the swashplate rotates; a limiting mechanism is provided between one side of the upper sliding plate and the inner wall of the pump body to prevent the upper sliding plate from rotating.

[0009] Preferably, the upper sliding plate is fastened to the side opposite to the swashplate, and the lower sliding plate is provided with a spherical annular groove at the position of the annular boss on the end cover, and the annular boss is provided with a supporting ball joint that is adapted to the spherical annular groove.

[0010] Preferably, the supporting ball joint is detachably connected to the annular boss of the end cap.

[0011] Preferably, a spherical cavity is provided between the lower sliding plate and the upper sliding plate at the position corresponding to the plunger, and a spherical sleeve I is universally connected inside the spherical cavity, and the spherical sleeve I is movably sleeved with the plunger.

[0012] Preferably, the annular boss of the end cap is fitted with a pressure plate that is fastened to the end cap. A spherical cavity is provided between the pressure plate and the end cap at the position corresponding to the plunger. A spherical sleeve II is universally connected in the spherical cavity, and the spherical sleeve II is movably fitted with the plunger.

[0013] Preferably, the limiting mechanism includes a groove provided on the upper sliding plate, and a limiting pin provided on the inner wall of the pump body with one end slidingly engaged with the groove; or a limiting pin is provided on one side of the upper sliding plate, and a groove is provided on the inner wall of the pump body with slidingly engaged with the limiting pin.

[0014] Preferably, the swash plate is provided with a plurality of oil passage holes arranged circumferentially between the oil discharge chamber and the high-pressure oil chamber to connect the oil discharge chamber and the high-pressure oil chamber, and the diameter of the oil passage hole located at the eccentric part of the swash plate is larger than the diameter of the oil passage holes on both sides thereof.

[0015] Preferably, the main shaft and the end cover are rotatably connected by a needle roller bearing, and an oil seal is installed between the main shaft and the end cover.

[0016] Preferably, a sealing ring is provided between the pump body and the end cover.

[0017] The present invention discloses a free-plunger hydraulic pump without lateral force. Due to the adoption of the technical solution described above, the present invention has the following beneficial effects:

[0018] 1. By adopting a swashplate structure, the distribution plate structure is eliminated, and the functions of the swashplate and distribution plate are integrated;

[0019] 2. The center of mass of the swashplate is located on the axis of rotation of the swashplate, thus eliminating the centrifugal force of the swashplate rotation;

[0020] 3. The plunger assembly is connected at both ends by ball joints, which eliminates lateral forces and provides better stress distribution, enabling higher speed operation. The plunger moves freely between the two ball sleeves, and the pressure on both sides of the plunger is balanced, which avoids excessive axial velocity and acceleration of the plunger under high-speed operation conditions, thus improving stability.

[0021] 4. It avoids the rotational movement of the plunger following the rotor assembly in the existing technology, and realizes the plunger assembly swinging within a small range, resulting in a smaller centrifugal force.

[0022] 5. The plunger structure is simple and easy to process; the plunger structure has good stress distribution, and the plunger length can be greatly reduced, only needing to ensure sufficient sealing length, resulting in a more compact structure;

[0023] 6. The rotor structure and slipper structure have been eliminated, resulting in a smaller moment of inertia, fewer friction pairs, and significantly improved reliability;

[0024] 7. The relative speed between the friction pairs is low, resulting in high reliability. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of the present invention;

[0026] Figure 2 This is a schematic diagram of the three-dimensional structure of the swashplate;

[0027] Figure 3 This is a schematic diagram of the three-dimensional structure of the swashplate;

[0028] Figure 4 This is a schematic diagram of the plunger structure.

[0029] In the diagram: 1. Pump body; 2. End cover; 3. Main shaft; 4. Outlet; 5. Inlet; 6. Swashplate; 7. Upper sliding plate; 8. Piston; 9. Oil passage hole; 10. Oil discharge chamber; 11. High-pressure oil chamber; 12. Counterweight; 13. Support ball joint; 14. Spherical sleeve I; 15. Pressure plate; 16. Spherical sleeve II; 17. Limiting mechanism; 18. Oil seal; 19. Sealing ring; 20. Lower sliding plate; 21. Oil passage hole. Detailed Implementation

[0030] The present invention can be explained in detail through the following embodiments. The purpose of disclosing the present invention is to protect all technical improvements within the scope of the present invention. In the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "front", "rear", "left", "right" indicating the orientation or positional relationship, they are only corresponding to the drawings of this application for the convenience of describing the present invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation.

[0031] Example 1:

[0032] Combined with appendix Figures 1-3 A free-plunger hydraulic pump without lateral force includes a pump body 1 and an end cover 2. The pump body 1 has a cavity and is open at one end. The end cover 2 is installed at the open end. The end cover 2 is rotatably connected to a main shaft 3 that extends into the cavity of the pump body 1. The main shaft 3 can be driven by a motor. The closed end of the pump body 1 has a liquid outlet 4, and the side corresponding to the liquid outlet 4 has a liquid inlet 5, that is, liquid can enter the pump body 1 from the liquid inlet 5. The main shaft 3 and the end cover 2 are rotatably connected by a needle roller bearing. An oil seal 18 is installed between the main shaft 3 and the end cover 2. A sealing ring 19 is provided between the pump body 1 and the end cover 2, which can effectively ensure the overall sealing performance.

[0033] It also includes a swashplate 6 and an upper sliding plate 7; the swashplate 6 is installed at one end of the main shaft 3 located inside the pump body 1, and the axis of the swashplate 6 does not coincide with the axis of the main shaft 3, that is, the main shaft 3 drives the swashplate 6 to rotate, and the swashplate 6 is eccentrically set; a counterweight part 12 is provided on the side of the outer circle of the swashplate 6 away from its eccentric part to make the center of mass of the swashplate 6 coincide with the axis of the main shaft 3, which effectively eliminates the centrifugal force of the rotation of the swashplate 6 and avoids large vibrations of the pump body 1 during operation; one end of the swashplate 6 corresponding to the closed end of the pump body 1 is a straight surface and slides in contact with the closed end of the pump body 1, and this end of the swashplate 6 is provided with an oil discharge chamber 10 that communicates with the liquid outlet 4; the other end of the swashplate 6 is an inclined surface, and the length of one side of the eccentric part of the swashplate 6 is greater than the length of the other side, and the swashplate 6 is inclined. The inclined end is provided with a high-pressure oil chamber 11 corresponding to and connected to the oil drain chamber 10. The high-pressure oil chamber 11 is an annular groove, and the axis of the high-pressure oil chamber 11 coincides with the axis of the swash plate 6, that is, the high-pressure oil chamber 11 moves eccentrically with the rotation of the swash plate 6. As needed, the swash plate 6 is provided with a plurality of oil passage holes 21 arranged circumferentially between the oil drain chamber 10 and the high-pressure oil chamber 11 to connect the oil drain chamber 10 and the high-pressure oil chamber 11. The diameter of the oil passage hole 21 located in the eccentric part of the swash plate 6 is larger than the diameter of the oil passage holes 21 on both sides. That is, the oil drain chamber 10 and the high-pressure oil chamber 11 are connected through the oil passage holes 21. At the same time, the large diameter of the oil passage hole 21 in the eccentric part of the swash plate 6 can reduce the weight, thereby reducing the size of the counterweight 12 and facilitating the optimization of the overall structure of the swash plate 6.

[0034] The inclined end of the swashplate 6 is slidably fitted with an upper sliding plate 7 that is movably sleeved with the main shaft 3, ensuring that the main shaft 3 and the upper sliding plate 7 do not interfere with each other. An annular boss is provided on the inner side of the end cover 2, which is movably sleeved with the main shaft 3. The upper sliding plate 7 is universally fitted with this annular boss, meaning that the upper sliding plate 7 can swing in space as the swashplate 6 rotates. Multiple hollow plungers 8 are arranged circumferentially between the upper sliding plate 7 and the end cover 2. The plungers 8 and the upper sliding plate 7, as well as the plungers 8 and the end cover 2, are movably inserted. As the upper sliding plate 7 swings, the volume of the cavity between the plungers 8 and the upper sliding plate 7 changes. The upper sliding plate 7 has oil passage holes 9 corresponding to the plungers 8, communicating with the inner cavity of the plungers 8. During the rotation of the swashplate 6, the oil passage holes 9 can communicate with the high-pressure oil chamber 11 and are exposed to the pressure as the swashplate 6 rotates. The swashplate 6 also has a counterweight. On one side of 12, the high-pressure oil chamber 11 rotates eccentrically, allowing the oil passage hole 9 to enter and exit the high-pressure oil chamber 11 with its rotation. As the oil passage hole 9 is exposed to enter the high-pressure oil chamber 11, the volume of the cavity between the oil passage hole 9 and the inner cavity of the plunger 8 decreases from large to small. Conversely, when the oil passage hole 9 is exposed, the volume of the cavity between the oil passage hole 9 and the inner cavity of the plunger 8 increases from small to large. When the oil passage hole 9 is exposed, the liquid in the pump body 1 enters the cavity between the oil passage hole 9 and the inner cavity of the plunger 8. After the oil passage hole 9 enters the high-pressure oil chamber 11, the liquid is forced into the high-pressure oil chamber 11 due to the decrease in cavity volume, and then enters the oil discharge chamber 10 and is discharged through the liquid outlet 4, thus achieving the purpose of high-pressure delivery. During operation, the plunger 8 only swings within a small range, and the centrifugal force is small, effectively eliminating lateral force and enabling higher speed operation.

[0035] A limiting mechanism 17 is provided between one side of the upper sliding plate 7 and the inner wall of the pump body 1 to prevent the upper sliding plate 7 from rotating. That is, the limiting mechanism 17 can prevent the upper sliding plate 7 from rotating axially. As needed, the limiting mechanism 17 includes a sliding groove provided on the upper sliding plate 7, and a limiting pin is provided on the inner wall of the pump body 1 with one end slidingly engaged with the sliding groove; or a limiting pin is provided on one side of the upper sliding plate 7, and a sliding groove is provided on the inner wall of the pump body 1 to slidely engage with the limiting pin. That is, the upper sliding plate 7 is prevented from rotating axially by the cooperation of the limiting pin and the sliding groove, while not affecting the swing of the upper sliding plate 7.

[0036] During use, the inlet 5 is connected to the container containing the liquid to ensure that the liquid can enter the inner cavity of the pump body 1 through the inlet 5. The motor is started, and the motor drives the main shaft 3. The main shaft 3 drives the swashplate 6 to rotate. The upper sliding plate 7 can swing in space with the rotation of the swashplate 6. When the oil passage hole 9 is exposed, the liquid in the pump body 1 enters the cavity between the oil passage hole 9 and the inner cavity of the plunger 8. After the oil passage hole 9 enters the high-pressure oil chamber 11, the volume of the cavity decreases, and the liquid is forced into the high-pressure oil chamber 11. Then it enters the oil discharge chamber 10 and is discharged through the outlet 4, thus achieving the purpose of high-pressure transportation.

[0037] Example 2:

[0038] Combined with appendix Figures 1-3A free-plunger hydraulic pump without lateral force is disclosed. The difference from Embodiment 1 is that, based on Embodiment 1, the upper sliding plate 7 is fastened to the side opposite to the swashplate 6 with a lower sliding plate 20. The lower sliding plate 20 has a spherical annular groove at the position corresponding to the annular boss of the end cover 2. The annular boss has a supporting ball joint 13 that corresponds to and matches the spherical annular groove. The supporting ball joint 13 enables a universal connection between the lower sliding plate 20 and the annular boss of the end cover 2, ensuring smooth swinging of the upper sliding plate 7 and the lower sliding plate 20. The supporting ball joint 13 is detachably connected to the annular boss of the end cover 2; that is, the supporting ball joint 13 and the annular boss of the end cover 2 can be either an integral structure or a detachable separate structure. Wear-resistant materials can be used to process the supporting ball joint 13 separately, or the spherical surface of the supporting ball joint 13 can be treated with wear-resistant materials to improve its service life.

[0039] Example 3:

[0040] Combined with appendix Figures 1-4 A free-plunger hydraulic pump without lateral force, based on embodiment two, has a spherical cavity between the lower sliding plate 20 and the upper sliding plate 7 corresponding to the position of the plunger 8. A spherical sleeve I14 is universally connected in the spherical cavity. The spherical sleeve I14 is movably sleeved with the plunger 8, that is, the plunger 8 is universally connected to the upper sliding plate 7 through the spherical sleeve I14 to avoid accidental jamming.

[0041] Example 4:

[0042] Combined with appendix Figures 1-4 A free-plunger hydraulic pump without lateral force, based on any one of the embodiments one to three, wherein the end cover 2 has an annular boss fitted with a pressure plate 15 that is fastened to the end cover 2, and a spherical cavity is provided between the pressure plate 15 and the end cover 2 at the position corresponding to the plunger 8. A spherical sleeve II 16 is universally connected in the spherical cavity. The spherical sleeve II 16 is movably fitted with the plunger 8, that is, the plunger 8 is universally connected to the end cover 2 through the spherical sleeve II 16, which increases the flexibility of the plunger 8 and further prevents the plunger 8 from accidentally jamming with the upper sliding plate 7.

[0043] The parts of this invention not described in detail are prior art. It will be apparent to those skilled in the art that this invention is not limited to the details of the above exemplary embodiments, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be regarded as exemplary and non-limiting in all respects, and are intended to encompass all changes falling within the meaning and scope of equivalents within this invention.

Claims

1. A free-plunger hydraulic pump without lateral force, comprising a pump body (1) and an end cover (2), wherein the pump body (1) has a cavity and one end is open, and the end cover (2) is installed at the open end, and the end cover (2) is rotatably connected to a main shaft (3) extending into the cavity of the pump body (1), and the closed end of the pump body (1) is provided with a liquid outlet (4), and a liquid inlet (5) is provided on the side corresponding to the liquid outlet (4); characterized in that: It also includes a swash plate (6) and an upper sliding plate (7); the swash plate (6) is installed at one end of the main shaft (3) located in the inner cavity of the pump body (1), and the axis of the swash plate (6) does not coincide with the axis of the main shaft (3). The outer circle of the swash plate (6) is provided with a counterweight (12) on the side away from its eccentric part to make the center of mass of the swash plate (6) coincide with the axis of the main shaft (3). The end of the swash plate (6) corresponding to the closed end of the pump body (1) is a flat surface and is in sliding contact with the closed end of the pump body (1). The end of the swash plate (6) is provided with an oil discharge chamber (10) corresponding to the liquid outlet (4); the other end of the swash plate (6) is an inclined surface, and the length of one side of the eccentric part of the swash plate (6) is greater than the length of the other side. The inclined end of the swash plate (6) is provided with a high-pressure oil chamber (11) corresponding to the oil discharge chamber (10). The high-pressure oil chamber (11) is an annular groove, and the axis of the high-pressure oil chamber (11) coincides with the axis of the swash plate (6). The inclined end of the swash plate (6) is slidably fitted with an upper sliding plate (7) that is movably sleeved with the main shaft (3); the inner side of the end cover (2) is provided with an annular boss that is movably sleeved with the main shaft (3), and the upper sliding plate (7) is universally fitted with the annular boss; a plurality of hollow plungers (8) are arranged circumferentially between the upper sliding plate (7) and the end cover (2), and the plungers (8) and the upper sliding plate (7) and the end cover (2) are movably inserted; the upper sliding plate (7) is provided with oil passage holes (9) corresponding to the plungers (8) at the position of the upper sliding plate (7), which are connected to the inner cavity of the plungers (8), and the oil passage holes (9) can be connected to the high pressure oil chamber (11) during the rotation of the swash plate (6), and are exposed on the side of the swash plate (6) where the counterweight part (12) is provided as the swash plate (6) rotates; a limiting mechanism (17) is provided between the side of the upper sliding plate (7) and the inner wall of the pump body (1) to prevent the upper sliding plate (7) from rotating.

2. The free-plunger hydraulic pump without lateral force as described in claim 1, characterized in that: The upper sliding plate (7) is fastened to the side away from the swash plate (6) with a lower sliding plate (20). The lower sliding plate (20) is provided with a spherical annular groove at the position of the annular boss of the end cover (2). The annular boss is provided with a supporting ball joint (13) that is adapted to the spherical annular groove.

3. The free-plunger hydraulic pump without lateral force as described in claim 2, characterized in that: The supporting ball joint (13) is detachably connected to the annular boss of the end cap (2).

4. The free-plunger hydraulic pump without lateral force as described in claim 2, characterized in that: A spherical cavity is provided between the lower sliding plate (20) and the upper sliding plate (7) at the position corresponding to the plunger (8). A spherical sleeve I (14) is universally connected inside the spherical cavity, and the spherical sleeve I (14) is movably sleeved with the plunger (8).

5. The free-plunger hydraulic pump without lateral force as described in claim 1 or 2, characterized in that: The end cap (2) has an annular boss fitted with a pressure plate (15) that is fastened to the end cap (2). A spherical cavity is provided between the pressure plate (15) and the end cap (2) at the position corresponding to the plunger (8). A spherical sleeve II (16) is universally connected in the spherical cavity. The spherical sleeve II (16) is movably fitted with the plunger (8).

6. The free-plunger hydraulic pump without lateral force as described in claim 1, characterized in that: The limiting mechanism (17) includes a groove provided on the upper sliding plate (7), and a limiting pin with one end slidingly engaged with the groove is provided on the inner wall of the pump body (1); or a limiting pin is provided on one side of the upper sliding plate (7), and a groove is provided on the inner wall of the pump body (1) that slidesly engaged with the limiting pin.

7. The free-plunger hydraulic pump without lateral force as described in claim 1, characterized in that: The swash plate (6) is provided with a plurality of oil passage holes (21) arranged circumferentially between the oil discharge chamber (10) and the high pressure oil chamber (11) to connect the oil discharge chamber (10) and the high pressure oil chamber (11). The diameter of the oil passage hole (21) located in the middle of the eccentric part of the swash plate (6) is larger than the diameter of the oil passage holes (21) on both sides thereon.

8. The free-plunger hydraulic pump without lateral force as described in claim 1, characterized in that: The main shaft (3) and the end cover (2) are rotatably connected by a needle roller bearing, and an oil seal (18) is installed between the main shaft (3) and the end cover (2).

9. The free-plunger hydraulic pump without lateral force as described in claim 1, characterized in that: A sealing ring (19) is provided between the pump body (1) and the end cover (2).

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