Four-quadrant ultra-high pressure plunger pump

Abstract

The application discloses a four-quadrant superhigh-pressure plunger pump, which comprises a main shaft, a shell, a first bearing, a swash plate, a plunger return and cylinder pre-pressing device, an odd number of plunger assemblies, a cylinder, a second bearing and a distribution disc; the distribution disc has the function of a pump end cover and is coaxially arranged on the shell; the first bearing and the second bearing are arranged on the shell and the distribution disc respectively; the distribution disc and the cylinder distribution surface are spherical; two distribution windows are symmetrically arranged on the distribution disc and are communicated with pump oil inlets and outlets through three or more transition channels; and the maximum inclination angle of the swash plate is not more than 13 DEG. The plunger pump can adapt to four-quadrant working conditions and superhigh-pressure working conditions above 60 MPa.

Description

Technical Field

[0001] This invention relates to a piston pump, and specifically to a four-quadrant ultra-high pressure piston pump, within the field of hydraulic component technology. Background Technology

[0002] With the rise of servo pump control technology, piston pumps adaptable to four-quadrant operating conditions are being used more and more widely. The four-quadrant operating conditions include: pump operating condition with clockwise rotation, pump operating condition with counterclockwise rotation, motor operating condition with clockwise rotation, and motor operating condition with counterclockwise rotation.

[0003] Currently, swashplate axial piston pumps adapted to four-quadrant operating conditions generally have pressure ratings between 21MPa and 35MPa, which cannot meet the application requirements of ultra-high pressure conditions above 60MPa. The main factors limiting the improvement of product pressure ratings are: First, swashplate axial piston pumps adapted to four-quadrant operating conditions require a distributor plate for flow distribution. Under ultra-high pressure conditions, the traditional pump end cover and distributor plate deform excessively, resulting in poor sealing between the distributor plate and the cylinder block flow distribution surface. Simultaneously, the back of the distributor plate and the contact surface between the pump end cover also have poor sealing, leading to large internal leakage and low volumetric efficiency. Second, the radial force borne by the piston in a swashplate piston pump is proportional to the working pressure. Under ultra-high pressure conditions, the radial force between the piston and the piston bore in conventional piston pumps is excessive, resulting in excessive contact stress and contact specific work, which can lead to rapid wear of the friction pair or even piston jamming and damage. Therefore, how to provide a swashplate axial piston pump that can adapt to both four-quadrant and ultra-high pressure conditions is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] To address the problems existing in the background art, the present invention provides a four-quadrant ultra-high pressure plunger pump. The pump's structure is a swashplate axial plunger pump with spherical flow distribution, suitable for four-quadrant operating conditions and ultra-high pressure conditions above 60 MPa.

[0005] The technical solution adopted in this invention is:

[0006] The four-quadrant ultra-high pressure plunger pump of the present invention includes a main shaft, a housing, a first bearing, a swashplate, a plunger return and cylinder pre-compression device, an odd number of plunger assemblies, a cylinder, a second bearing, and a distribution plate.

[0007] The distribution plate also functions as a pump end cover, and the distribution plate is coaxially mounted on the housing.

[0008] The distribution surface of the distribution plate is a convex spherical surface. A bearing hole and an oblong distribution window are provided on one side of the distribution surface of the distribution plate. The end of the main shaft is located in the bearing hole. The oblong distribution windows are symmetrically arranged and their distribution circle is coaxial with the bearing hole. The distribution plate is also provided with pump inlet / outlet and pump outlet / inlet. Each oblong distribution window has three or more parallel distribution channels evenly spaced in the circumferential direction. The pump inlet / outlet is connected to the first oblong distribution window through each first distribution channel. The pump outlet / inlet is connected to the second oblong distribution window through each second distribution channel. Both ends of the oblong distribution window are provided with corresponding connected damping grooves or damping holes. In specific implementation, for ease of processing, triangular damping grooves can be provided. The tip of the damping groove is away from the end of the oblong distribution window, and the depth increases linearly from the tip towards the oblong distribution window.

[0009] The flow distribution surface of the cylinder body is a concave spherical surface. The radius of the concave spherical surface of the cylinder body is equal to the radius of the convex spherical surface of the flow distribution plate. An odd number of plunger holes are evenly distributed around the circumference of the cylinder body. The bottom of each plunger hole is connected to its flow distribution surface through a transition channel opened in the cylinder body.

[0010] A first bearing is mounted on the housing, and a second bearing is mounted on the distribution plate. The two ends of the main shaft are supported by the first and second bearings, respectively. The cylinder block is coaxially mounted on the main shaft, and the cylinder block and the main shaft are connected by a spline. The distribution surface of the cylinder block contacts the distribution surface of the distribution plate. The cylindrical ends of the odd-numbered plunger assemblies are slidably mounted in evenly distributed plunger holes on the cylinder block. The slipper end faces of the odd-numbered plunger assemblies contact the working surface of the swashplate. The return stroke and cylinder preload device is installed between each plunger assembly and the cylinder to provide return force to each plunger assembly and preload force to the cylinder, so that the slipper end face keeps in contact with the working surface of the swashplate, and the flow distribution surface of the cylinder keeps in contact with the flow distribution surface of the flow distribution plate; the plunger return stroke and cylinder preload device includes a ball joint, a return plate and a spring. The return plate is obliquely fitted on the slipper of each plunger assembly. The ball joint is movably installed at the center of the return plate and coaxially fitted on the main shaft. The spring is coaxially fitted on the main shaft and located inside the ball joint and between the other end face of the cylinder.

[0011] The maximum tilt angle α of the swashplate is no greater than 13°.

[0012] The swash plate, plunger return and cylinder pre-compression device, cylinder and distributor plate are coaxially mounted on the main shaft along the length of the main shaft. The housing is coaxially mounted on the swash plate and cylinder. The distributor plate is coaxially mounted on one end of the housing by several bolts. Each plunger assembly is installed in the cylinder. The cylinder and distributor plate are in spherical contact. The distributor plate is symmetrically provided with waist-shaped distribution windows for distribution and with several distribution channels. During the rotation of the cylinder, the distribution surface of the cylinder is connected in sequence to the first waist-shaped distribution window, the upper dead center transition zone, the second waist-shaped distribution window and the lower dead center transition zone of the distributor plate.

[0013] The swashplate angle can be fixed or variable. This invention is applicable to both swashplate-type fixed displacement piston pumps and swashplate-type variable displacement piston pumps.

[0014] The upper dead center transition zone and lower dead center transition zone of the distribution plate are also provided with multiple vibration damping blind holes. When the plunger pump operates under ultra-high pressure conditions, the pressure difference between the waist-shaped distribution windows on both sides of the distribution plate is too large, and the pressure impact is large when the plunger cavity switches between high and low pressure. In addition to setting vibration damping grooves or vibration damping holes, adding vibration damping blind holes can act as hydraulic springs, which helps to reduce vibration and noise.

[0015] The second bearing installed on the distribution plate is a needle roller bearing or a cylindrical roller bearing. Under the same load-bearing capacity, the outer diameter of the needle roller bearing or the cylindrical roller bearing is smaller, so the wall thickness between the waist-shaped groove of the distribution plate and the bearing hole is larger, the distribution plate has higher pressure resistance and better rigidity, less deformation of the distribution surface, and better sealing effect of the distribution surface.

[0016] A shaft seal is installed between the housing and the main shaft as a rotary dynamic seal, and a sealing ring is installed between the housing and the distribution plate as a static seal. An oil drain port is provided on the distribution plate or the housing. When the plunger pump is installed outside the oil tank, no external leakage will occur. It should be noted that when the plunger pump is installed inside the oil tank, the rotary dynamic seal and static seal can be omitted; furthermore, if the circumferential clearance between the housing and the main shaft is large enough, the oil in the pump housing cavity can connect to the oil tank through the gaps between the bearing steel balls or rollers and then through the circumferential clearance between the housing and the main shaft, and an oil drain port may not be provided on the distribution plate or the housing.

[0017] The plunger pump of this invention is suitable for four-quadrant operating conditions and ultra-high pressure conditions above 60MPa. The plunger pump adopts a swashplate axial plunger pump structure with low rotational inertia, making it particularly suitable for conditions requiring high-frequency switching between forward and reverse rotation of the spindle. When applied to a servo pump-controlled volumetric speed regulation system, the smaller rotational inertia allows for higher response speeds. The distributor plate also serves as the pump's end cover, eliminating the internal leakage point on the back of the distributor plate compared to conventional products. Furthermore, the distributor plate and cylinder block distribution surface are spherical, with a self-centering function, resulting in better sealing and higher volumetric efficiency. The two waist-shaped distribution windows of the distributor plate are connected to the inlet and outlet ports through three or more distribution channels, ensuring sufficient flow area while effectively isolating the multiple distribution channels. The distribution plate acts as a reinforcing rib, resulting in better rigidity, less spherical deformation under ultra-high pressure, and better sealing performance. The distribution plate also functions as an end cap; by installing a second bearing on the distribution plate, the distance between the two bearing support points of the main shaft is shorter, thus improving the bending rigidity of the main shaft for the same shaft diameter. When the radial force on the plunger assembly acts on the main shaft through the cylinder, the main shaft's flexural deformation is smaller, preventing poor sealing of the distribution surface caused by large-scale cylinder rotation with the main shaft. With a swashplate tilt angle not exceeding 13°, the radial force on the plunger assembly is reduced under the same pressure, ensuring that the contact pressure and contact work between the plunger assembly and the cylinder bore do not exceed the material's allowable limits under ultra-high pressure conditions. Furthermore, the smaller radial force further reduces the bending deformation of the main shaft.

[0018] The beneficial effects of this invention are:

[0019] The four-quadrant ultra-high pressure plunger pump of the present invention has a swashplate axial plunger pump with spherical flow distribution, which can adapt to four-quadrant working conditions and ultra-high pressure conditions above 60MPa. Attached Figure Description

[0020] Figure 1 This is a cross-sectional view of the structure of Embodiment 1 of the present invention;

[0021] Figure 2 This is a front view of the distribution plate according to Embodiment 1 of the present invention;

[0022] Figure 3 This is a cross-sectional view along the XX direction of the distribution plate in Embodiment 1 of the present invention;

[0023] Figure 4 This is a front view of the distribution plate according to Embodiment 2 of the present invention;

[0024] In the diagram: 1. Main shaft, 2. Housing, 3. First bearing, 4. Swashplate, 5. Plunger return and cylinder preload device, 5.1. Ball joint, 5.2. Return plate, 5.3. Spring, 6. Plunger assembly, 7. Cylinder, 7-1. Transition channel, 8. Second bearing, 9. Distribution plate, 9-1. Pump inlet / outlet, 9-2. Pump outlet / inlet, 9-3. Drain port, 9-4. First waist-shaped distribution window, 9-4-1. First distribution channel, 9-5. Second waist-shaped distribution window, 9-5-1. Second distribution channel, 9-6. Bearing hole, 9-7. Vibration damping groove, 9-8. Vibration damping blind hole, 10. Shaft seal, 11. Sealing ring. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Example 1:

[0027] like Figure 1 , Figure 2 and Figure 3 As shown, the four-quadrant ultra-high pressure plunger pump of the present invention includes a main shaft 1, a housing 2, a first bearing 3, a swashplate 4, a plunger return and cylinder pre-compression device 5, seven plunger assemblies 6, a cylinder 7, a second bearing 8, a distribution plate 9, a shaft seal 10, and a sealing ring 11.

[0028] The plunger return and cylinder preload device 5 includes a return plate 5.1, a ball joint 5.2, and a spring 5.3. Its function is to provide return force for the plunger assembly 6 and preload force for the cylinder 7. The left end of the spring 5.3 presses the slipper of the plunger assembly 6 through the ball joint 5.2 and then through the return plate 5.1, so that the slipper plane keeps in contact with the plane of the swashplate 4. At the same time, the right side of the spring 5.3 acts on the tail end of the cylinder 7, and the spring force simultaneously provides preload force for the cylinder 7, so that the spherical surface of the cylinder 7 keeps in contact with the spherical surface of the distributor plate 9.

[0029] The plunger return and cylinder pre-compression device 5 used in this embodiment has a wear compensation function, as the spring force can still ensure that the plane of the slipper remains in contact with the plane of the swashplate 4 even after the return plate 5.1 or the slipper wears. However, other solutions can also be adopted for the plunger return and cylinder pre-compression device. For example, an end face limiting device can be added to the return plate 5.1 to keep the return plate 5.1 and the slipper close to zero gap, which can also ensure that the plane of the slipper remains in contact with the plane of the swashplate 4, providing return force for the plunger assembly 6. At the same time, the ball joint 5.2 can be eliminated, and the left end of the spring 5.3 acts on the main shaft 1, while the right end of the spring 5.3 acts on the tail of the cylinder 7, providing pre-compression force for the cylinder 7. Alternatively, an end face limiting device can be added to the return plate 5.1 based on the plunger return and cylinder pre-compression device in embodiment 1 to improve the return reliability of the plunger assembly 6.

[0030] The distribution plate 9 also functions as a pump end cover, and is coaxially fixedly mounted on the housing 1. In this embodiment, the distribution plate 9 is fastened to the housing 1 with four screws. The distribution plate 9's integrated design with the pump end cover offers several advantages: First, compared to conventional products, it eliminates the internal leakage point between the back of the distribution plate 9 and the end cover, resulting in higher volumetric efficiency for the plunger pump and a smaller decrease in volumetric efficiency under ultra-high pressure conditions. In other words, it is more suitable for ultra-high pressure conditions. Second, by setting bearing holes 9-6 on the distribution plate 9, the support center of the second bearing 8 is closer to the support center of the first bearing 3. Therefore, the distance between the two bearing support points of the main shaft 1 is shorter, resulting in better bending rigidity of the main shaft 1 under the same shaft diameter. When the radial force on the plunger assembly 6 is applied to the main shaft 1 through the cylinder 7, the flexural deformation of the main shaft 1 is smaller. This avoids poor sealing of the distribution surface caused by the large-scale flexural rotation of the cylinder 7 with the main shaft 1, effectively improving the pressure rating of the plunger pump and the volumetric efficiency under ultra-high pressure conditions. In conventional products, the second bearing 8 is located on the end cover, and the main shaft 1 passes through the distribution plate 9 before inserting into the second bearing 8. Therefore, the distance between the two bearing support points of the main shaft 1 is much larger, which is obvious.

[0031] The distribution surface of the distributor plate 9 is an outwardly convex spherical surface, while the distribution surface of the cylinder block 7 is an inwardly concave spherical surface. The radii of the inwardly concave spherical surface and the outwardly convex spherical surface are equal, both being SR. The two are coupled and paired. In specific implementation, the distribution surfaces of the distributor plate 9 and the cylinder block 7 are usually paired and ground to ensure the sealing performance of the distribution surfaces.

[0032] The distribution surface shape of the cylinder block 7 and the distributor plate 9 can be either planar or spherical. Planar distribution has lower manufacturing costs, but when the cylinder block 7 is subjected to overturning moment, a wedge-shaped gap will form between the distribution surface of the cylinder block 7 and the distribution surface of the distributor plate 9, increasing the leakage of the distribution surface. This drawback becomes more pronounced at higher pressures. Spherical distribution has higher manufacturing costs, but when the cylinder block 7 is subjected to overturning moment, the spherical distribution surface of the cylinder block 7 can automatically align with the spherical distribution surface of the distributor plate 9, thus providing better sealing performance and making it more suitable for ultra-high pressure conditions.

[0033] The distribution plate 9 has a bearing hole 9-6 and two waist-shaped distribution windows 9-4 and 9-5 on one side of its distribution surface. The two waist-shaped distribution windows 9-4 and 9-5 are symmetrically arranged and their distribution circle is coaxial with the bearing hole 9-6. The distribution plate 9 is also provided with an oil inlet / outlet 9-1 and an oil outlet / inlet 9-2. The oil inlet 9-1 is connected to the first waist-shaped distribution window 9-4 through five parallel first distribution channels 9-4-1, and the oil inlet 9-2 is connected to the second waist-shaped distribution window 9-5 through five parallel second distribution channels 9-5-1.

[0034] The plunger pump has clockwise and counterclockwise rotation modes. Looking at the shaft end: When the main shaft 1 rotates clockwise, the first waist-shaped distribution window 9-4 is the oil suction window and the second waist-shaped distribution window 9-5 is the oil discharge window. The first waist-shaped distribution window 9-4 draws oil from the outside through five parallel first distribution channels 9-4-1 and then through the oil port 9-1. The second waist-shaped distribution window 9-5 discharges oil to the outside through five parallel second distribution channels 9-5-1 and then through the oil port 9-2. When the main shaft 1 rotates counterclockwise, the second waist-shaped distribution window 9-5 is the oil suction window and the first waist-shaped distribution window 9-4 is the oil discharge window. The second waist-shaped distribution window 9-5 draws oil from the outside through five parallel second distribution channels 9-5-1 and then through the oil port 9-2. The first waist-shaped distribution window 9-4 discharges oil to the outside through five parallel first distribution channels 9-4-1 and then through the oil port 9-1.

[0035] In this embodiment, the distribution channels 9-4-1 and 9-5-1 in the two waist-shaped distribution windows 9-4 and 9-5 are five parallel cylindrical holes, with the inter-hole walls acting as reinforcing ribs. The reason for emphasizing three or more distribution channels 9-4-1 and 9-5-1 in the invention description is that this design allows for the formation of multiple evenly spaced reinforcing ribs on the distribution window channels, effectively improving the pressure-bearing capacity and rigidity of the distribution plate 9 to adapt to ultra-high pressure conditions. Even under ultra-high pressure conditions, the stress deformation of the distribution spherical surface of the distribution plate 9 is very small, resulting in better sealing performance and higher volumetric efficiency.

[0036] Both ends of the two waist-shaped distribution windows 9-4 and 9-5 are provided with damping grooves 9-7 or damping holes that communicate with the corresponding distribution windows 9-4 and 9-5, in order to reduce the pressure impact during the switching of high and low pressure in the plunger cavity and reduce noise and vibration. The damping grooves 9-7 or damping holes can take various forms, such as the gradually changing cross-section triangular groove in this embodiment, or the stepped arc-shaped groove, or the throttling orifice. The various forms of the damping grooves 9-7 are common knowledge to those skilled in the art and will not be elaborated upon here.

[0037] The cylinder block 7 has seven plunger holes evenly distributed around its circumference, with one plunger assembly 6 installed in each hole. The bottom of the plunger hole is connected to the flow distribution surface via a transition channel 7-1. Compared to using an even number of plunger assemblies 6, using an odd number of plunger assemblies 6 results in smaller flow pulsation. The more plunger assemblies 6 there are, the smaller the flow pulsation. Common numbers of plunger assemblies 6 are seven or nine, while a few products use five or eleven plunger assemblies 6.

[0038] The plunger assembly 6 includes a plunger body and a slipper, which are spherically hinged together. In this embodiment, a ball head is provided on the plunger body and a ball socket is provided on the slipper; however, a ball socket can also be provided on the plunger body and a ball head on the slipper, each with its own advantages and disadvantages.

[0039] A first bearing 3 is fixedly installed on the housing 2, and a second bearing 8 is fixedly installed on the distribution plate 9. The second bearing 8 installed on the distribution plate 9 is preferably a needle roller bearing or a cylindrical roller bearing. The reason is that under the same load capacity, the outer diameter of the needle roller bearing or the cylindrical roller bearing is smaller than that of the ball bearing. In this way, the wall thickness between the distribution channels 9-4-1 and 9-5-1 of the distribution plate 9 and the bearing hole 9-6 is thicker, the rigidity of the distribution plate 9 is better, the deformation of the distribution spherical surface is smaller under ultra-high pressure conditions, and the sealing of the distribution surface is more reliable.

[0040] The two ends of the main shaft 3 are supported by the first bearing 3 and the second bearing 8 respectively. The cylinder body 7 is coaxially mounted on the main shaft 3. The cylinder body 7 and the main shaft 1 are connected by a spline. The spline is usually an involute spline. The internal spline and the external spline are clearance fit. In this way, the cylinder body 7 can swing relatively slightly relative to the main shaft 1 to compensate for the flexural deformation of the main shaft 1 when it is subjected to radial force, and to ensure that the distribution surface of the cylinder body 7 is in close contact with the distribution surface of the distribution plate 9.

[0041] In this embodiment, the plunger pump is a fixed-displacement pump, and the swashplate 4 has a fixed tilt angle. The swashplate 4 is installed inside the housing 2. To prevent the swashplate 4 from rotating, a stop pin or other anti-rotation device is required. However, the solution described in this invention is also applicable to variable displacement pumps, where the swashplate 4 angle is adjustable. When applied to a variable displacement pump, a variable displacement mechanism and a variable displacement control valve are also required.

[0042] Regardless of whether it's a fixed displacement pump or a variable displacement pump, the maximum tilt angle of the swashplate 4 should not exceed 13°. The swashplate 4 angle in conventional plunger pumps is generally 17°–21°. This invention limits the swashplate 4 angle to no more than 13°, specifically for ultra-high pressure conditions above 60MPa. The higher the required pressure level, the smaller the recommended swashplate 4 angle. This is because the plunger assembly 6 of the swashplate plunger pump will bear a large radial force, which is proportional to the pressure and the tangent of the swashplate 4 tilt angle. If the swashplate 4 angle is set according to conventional product values, when applied to ultra-high pressure conditions, on the one hand, the contact stress and contact specific work between the plunger body and the plunger bore of assembly 6 will be too high, leading to accelerated wear and shortened lifespan. It may also cause jamming due to the contact stress and contact specific work exceeding the material's allowable limits. On the other hand, the weak point of the plunger assembly 6 is at its neck. The larger the swashplate 4 angle, the larger the required relative swing angle between the plunger body and the slipper, resulting in a smaller neck diameter. When applied to ultra-high pressure conditions, this can easily lead to excessive stress at the neck and breakage.

[0043] The plunger pump in this embodiment is suitable for installation outside the oil tank. A rotary dynamic seal (shaft seal 10) is also installed between the housing 2 and the main shaft 1, and a static seal (sealing ring 11) is installed between the housing 2 and the distribution plate 9. The distribution plate 9 is also provided with an oil drain port 9-3 that communicates with the inner cavity of the housing 2. The oil drain port 9-3 can also be provided on the housing 2.

[0044] However, when the plunger pump is installed inside the oil tank, the rotary dynamic seal and static seal can be eliminated; furthermore, if the circumferential clearance between the housing 2 and the main shaft 1 is large enough, the oil in the pump housing cavity can be connected to the oil tank through the gap between the bearing steel balls or rollers and then through the circumferential clearance between the housing 2 and the main shaft 1, and the drain port 9-3 may not be provided on the distribution plate 9 or the housing 2.

[0045] Example 2:

[0046] like Figure 4 The diagram shows another embodiment of the distribution plate 9 of the present invention. Compared with embodiment 1, the upper dead point and lower dead point transition zone of the distribution plate 9 are respectively provided with multiple damping blind holes 9-8, and the remaining structural features are the same as those in embodiment 1. When the plunger pump operates under ultra-high pressure conditions, the pressure difference between the distribution windows 9-4 and 9-5 on both sides of the distribution plate 9 is too large, and the pressure impact is large when the plunger cavity switches between high and low pressure. Based on the damping groove 9-7 or damping hole, the addition of damping blind holes in the transition zone can act as a hydraulic spring, which helps to reduce vibration and noise.

[0047] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A four-quadrant ultra-high pressure plunger pump, comprising a main shaft (1), a housing (2), a first bearing (3), a swashplate (4), a plunger return and cylinder pre-compression device (5), an odd number of plunger assemblies (6), a cylinder (7), a second bearing (8), and a distributor plate (9), characterized in that: The distribution plate (9) also functions as a pump end cover, and the distribution plate (9) is coaxially mounted on the housing (2); The distribution surface of the distribution plate (9) is a convex spherical surface. A bearing hole (9-6) and a first waist-shaped distribution window (9-4) and a second waist-shaped distribution window (9-5) are provided on one side of the distribution surface of the distribution plate (9). The first waist-shaped distribution window (9-4) and the second waist-shaped distribution window (9-5) are symmetrically arranged and their distribution circle is coaxial with the bearing hole (9-6). The distribution plate (9) is also provided with a pump inlet / outlet port (9-1) and a pump outlet / inlet port (9-2). The first waist-shaped distribution window (9-4) and the second waist-shaped distribution window (9-5) are also provided. Three or more parallel first distribution channels (9-4-1) and second distribution channels (9-5-1) are provided. The pump inlet / outlet (9-1) is connected to the first waist-shaped distribution window (9-4) through each of the first distribution channels (9-4-1). The pump outlet / inlet (9-2) is connected to the second waist-shaped distribution window (9-5) through each of the second distribution channels (9-5-1). Both ends of the first waist-shaped distribution window (9-4) and the second waist-shaped distribution window (9-5) are provided with corresponding connected damping grooves (9-7) or damping holes. The distribution surface of the cylinder (7) is a concave spherical surface. The radius of the concave spherical surface of the cylinder (7) is equal to the radius of the convex spherical surface of the distribution plate (9). An odd number of plunger holes are evenly distributed around the circumference of the cylinder (7). The bottom of each plunger hole is connected to its distribution surface through a transition channel (7-1) opened in the cylinder (7). A first bearing (3) is installed on the housing (2), and a second bearing (8) is installed on the distribution plate (9). The two ends of the main shaft (1) are supported by the first bearing (3) and the second bearing (8) respectively. The cylinder (7) is coaxially mounted on the main shaft (1). The cylinder (7) and the main shaft (1) are connected by a spline. The distribution surface of the cylinder (7) is in contact with the distribution surface of the distribution plate (9). The cylindrical ends of the odd number of plunger assemblies (6) are slidably mounted on the cylinder. The pistons are installed in the circumferentially distributed piston holes on the cylinder (7). The slipper end faces of the odd number of piston assemblies (6) are in contact with the working surface of the swashplate (4). The piston return and cylinder pre-compression device (5) is installed between each piston assembly (6) and the cylinder (7) to provide return force for each piston assembly (6) and pre-compression force for the cylinder (7), so that the slipper end faces are in contact with the working surface of the swashplate (4) and the distribution surface of the cylinder (7) is in contact with the distribution surface of the distribution plate (9). The maximum tilt angle α of the swashplate (4) is no greater than 13°.

2. The four-quadrant ultra-high pressure plunger pump according to claim 1, characterized in that: The swashplate (4) has a fixed angle or a variable angle.

3. A four-quadrant ultra-high pressure plunger pump according to claim 1, characterized in that: The upper dead point transition zone and the lower dead point transition zone of the distribution plate (9) are also provided with multiple shock-absorbing blind holes (9-8).

4. A four-quadrant ultra-high pressure plunger pump according to claim 1, characterized in that: The second bearing (8) installed on the distribution plate (9) is a needle roller bearing or a cylindrical roller bearing.

5. A four-quadrant ultra-high pressure plunger pump according to claim 1, characterized in that: A shaft seal (10) is installed between the housing (2) and the main shaft (1) as a rotary dynamic seal, and a sealing ring (11) is installed between the housing (2) and the distribution plate (9) as a static seal. An oil drain port (9-3) is provided on the distribution plate (9) or the housing (2).

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