Axial plunger pump

Abstract

The axial plunger pump comprises a shell and a cylinder body, the cylinder body is located in the shell, a cylinder body flow distribution face is arranged on the outer side of the middle of the cylinder body, a cylinder body oil hole is formed in the side wall of the cylinder body, and the cylinder body oil hole penetrates through the cylinder body flow distribution face; an oil suction port, an oil discharge port and a flow distribution ring belt are arranged on the shell, and an oil suction port flow distribution groove and an oil discharge port flow distribution groove are formed in the inner side of the flow distribution ring belt; the oil suction port is communicated with the oil suction port flow distribution groove, the oil discharge port is communicated with the oil discharge port flow distribution groove, the cylinder body oil hole is communicated with the oil suction port flow distribution groove or the oil discharge port flow distribution groove, and the limit rotating speed of the pump is high.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of pump design, and relates to an axial piston pump. BACKGROUND

[0002] Hydraulic systems play a vital role in many important fields such as engineering machinery, aerospace, large equipment, etc. As a key component of the hydraulic system, the axial piston pump is the power source of the hydraulic system. Compared with other types of hydraulic pumps, the axial piston pump has the advantages of compact structure, high volumetric efficiency, high pressure, convenient variable implementation, wide adjustable flow range, compact structure, high volumetric efficiency, and high power density, and is widely used in various hydraulic systems. As the most common power component of the hydraulic system, the performance of the axial piston pump is crucial to the performance of the hydraulic system.

[0003] Publication No. CN110513261A discloses a kind of symmetrical double flow distribution disc axial piston pump, including spindle, cylinder body, swash plate, plunger and sliding shoe, shell, return disc, bearing end cover and return disc compression device, the shell inside in the both ends of the cylinder body symmetrically distribute two swash plates;And the oil side of the swash plate and the oil suction side of the swash plate are machined with flow distribution window, two flow distribution windows are not communicated, the cylinder body is machined with a plurality of uniformly distributed plunger through holes around its axis;The both ends of the plunger through hole are equipped with the plunger, one end of the plunger axially penetrates the plunger through hole and is connected with one end of the sliding shoe, the inside of the plunger and the sliding shoe is machined with a through hole, forming an oil passage;The oil passage is communicated with the plunger through hole and the flow distribution window respectively, and the shell is machined with an oil discharge port communicated with the flow distribution window arranged on the oil side of the swash plate and an oil suction port communicated with the flow distribution window arranged on the oil suction side of the swash plate. The plunger and the sliding shoe have a through hole, and no longer use a small throttle hole structure. Instead, a relatively thick through hole structure is used as an oil passage. The side of the sliding shoe close to the swash plate adopts a flat form, and no longer has an annular oil groove for static pressure support.

[0004] Publication No. CN120402322A discloses an axial piston pump, comprising: a housing unit; a distribution plate unit located within the housing unit; the distribution plate unit includes a plate body and a support layer, the plate body having an oil discharge port and an oil suction port; the oil discharge port and the oil suction port are both arc-shaped and concentrically arranged; the inner diameter of the oil discharge port is equal to the inner diameter of the oil suction port; the outer diameter of the oil discharge port is equal to the outer diameter of the oil suction port; the support layer is fixedly connected to the plate body; the support layer has... An oil drain groove and an oil suction groove are provided; the oil drain groove is connected to the oil drain port; the oil drain groove is arc-shaped and concentrically arranged with the oil drain port; the central angle of the oil drain port coincides with the central angle of the oil drain groove; the inner diameter of the oil drain groove is smaller than the inner diameter of the oil drain port; the outer diameter of the oil drain groove is equal to the outer diameter of the oil drain port; an oil suction groove is connected to the oil suction port; the oil suction groove is arc-shaped and concentrically arranged with the oil suction port; the central angle of the oil suction port coincides with the central angle of the oil suction groove; the outer diameter of the oil suction groove is larger than the oil suction groove. The outer diameter of the inlet; the inner diameter of the oil suction groove is equal to the inner diameter of the oil suction port; a cylinder unit located inside the outer shell unit; one end of the cylinder unit is attached to the support layer; the cylinder unit is rotatably connected to the outer shell unit; the cylinder unit includes a cylinder body with multiple plunger cavities; multiple plunger units, each including a plunger rod and a plunger ball head; the plunger rod is slidably connected to the cylinder unit; the plunger rod and the plunger cavity are paired one-to-one. The following configuration should be provided: the plunger rod is slidably disposed within the plunger cavity; the plunger ball head is integrally formed with the plunger rod; a slipper unit is detachably connected to the plunger ball head; a swashplate unit is located within the housing unit; the swashplate unit is detachably connected to the housing unit; the slipper unit abuts against the swashplate unit; a drive shaft unit drives the cylinder unit to rotate; and a center spring unit drives the slipper unit to press against the swashplate unit.

[0005] With the development of hydraulic technology, axial piston pumps are gradually evolving towards miniaturization, high speed, and high pressure. To further improve their power density, increasing the limiting speed has become an important research direction. However, as the speed increases, the flow distribution surfaces of traditional axial piston pumps, using planar or spherical flow distribution, need to withstand a wide range of alternating loads. Simultaneously, limited by the piston pump's anti-cavitation capability, the working specific power ([PV] value) and anti-cavitation capability have approached or exceeded the material's working limits, meaning the speed cannot be increased indefinitely. Both the American standard AS19692B and the Chinese military standard GJB6397-2008 specify the maximum operating speed of piston pumps under different displacements. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide an axial piston pump with a high limiting speed.

[0007] To achieve the above objectives, the present invention discloses an axial piston pump, comprising a housing and a cylinder body. The cylinder body is located inside the housing, and a cylinder body distribution surface is provided on the outer side of the middle part of the cylinder body. A cylinder body oil hole is provided on the side wall of the cylinder body, and the cylinder body oil hole passes through the cylinder body distribution surface. An oil suction port, an oil discharge port, and a distribution ring are respectively arranged on the housing. An oil suction port distribution groove and an oil discharge port distribution groove are provided on the inner side of the distribution ring. The oil suction port is connected to the oil suction port distribution groove, the oil discharge port is connected to the oil discharge port distribution groove, and the cylinder body oil hole is connected to either the oil suction port distribution groove or the oil discharge port distribution groove.

[0008] Furthermore, the outer diameter of the cylinder block distribution surface is larger than the outer diameters at both ends of the cylinder block.

[0009] Furthermore, swash plates and return plates are provided on both sides of the cylinder body. A plunger hole is provided inside the cylinder body. One end of the plunger assembly is inserted into the plunger hole, and the other end of the plunger assembly is in contact with the swash plate.

[0010] Furthermore, a front pump cover is provided at one end of the housing, and a rear pump cover is provided at the other end of the housing. A shaft mounting hole is provided on the cylinder body. The drive shaft passes through the front pump cover, the swashplate, and the shaft mounting hole and is movably connected to the inner side of the rear pump cover. The cylinder body rotates with the drive shaft.

[0011] Furthermore, the swashplate is connected to the front pump cover by a first bolt; the swashplate is connected to the rear pump cover by a second bolt.

[0012] Furthermore, a bearing is provided between the outer wall of the cylinder and the inner wall of the housing.

[0013] Furthermore, the diameter of the distribution ring is smaller than the diameter of the two sides of the housing.

[0014] Furthermore, the number of oil holes in the cylinder block is the same as the number of plunger holes.

[0015] Furthermore, the width of the oil suction port distribution groove and the width of the oil discharge port distribution groove are equal to the diameter of the cylinder block oil hole; Furthermore, the diameter of the oil suction port is greater than or equal to the width of the oil suction port distribution groove; the diameter of the oil discharge port is greater than or equal to the width of the oil discharge port distribution groove.

[0016] The present invention has the following beneficial effects: In the specific operation of the plunger pump described in this invention, a cylinder distribution surface is provided on the outer side of the middle part of the cylinder body, and a cylinder oil hole is provided on the side wall of the cylinder body, which passes through the cylinder distribution surface; an oil suction port distribution groove and an oil discharge port distribution groove are provided on the inner side of the distribution ring; the oil suction port is connected to the oil suction port distribution groove, the oil discharge port is connected to the oil discharge port distribution groove, and the cylinder oil hole is connected to either the oil suction port distribution groove or the oil discharge port distribution groove. The flow area of ​​the cylinder oil hole is more than three times that of the traditional design method, which can significantly reduce the flow velocity, improve the anti-cavitation ability, and thus increase the pump's limiting speed.

[0017] Furthermore, this invention divides a single displacement into two parts, which share a cylinder block. The radial dimension of the cylinder block is smaller than that of the cylinder block designed with the original displacement, and the linear velocity at the outermost circle of the cylinder block is significantly reduced. Under the condition that the pressure P and the material bearing capacity are constant, the cylinder block flow distribution surface can withstand higher rotational speeds. Attached Figure Description

[0018] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of a plunger pump. Figure 2 This is a sectional view of the cylinder block; Figure 3 For along Figure 2 Sectional view along line AA; Figure 4 This is a sectional view of the shell 2; Figure 5 For along Figure 4 BB section view; Wherein, 1 is the cylinder block, 2 is the housing, 3 is the drive shaft, 4 is the plunger assembly, 5 is the front pump cover, 6 is the return assembly, 7 is the bearing, 8 is the swashplate, 9 is the rear pump cover, 11 is the shaft mounting hole, 12 is the plunger hole, 13 is the cylinder block oil hole, 14 is the cylinder block flow distribution surface, 21 is the oil suction port, 22 is the oil discharge port, 23 is the oil suction port flow distribution groove, 24 is the oil discharge port flow distribution groove, and 25 is the housing flow distribution surface. Detailed Implementation

[0019] 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, not all, of the embodiments of the present invention. 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.

[0020] In the description of this invention, it should be understood that the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0021] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0022] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Additionally, the character " / " in this invention generally indicates that the preceding and following objects have an "or" relationship.

[0023] It should be understood that although terms such as first, second, third, etc., may be used in the embodiments of the present invention to describe the preset range, these preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from one another. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0024] Depending on the context, the word "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection." Similarly, depending on the context, the phrase "if determination" or "if detection (of the stated condition or event)" can be interpreted as "when determination," "in response to determination," "when detection (of the stated condition or event)," or "in response to detection (of the stated condition or event)."

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0026] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0027] As is generally known, an axial piston pump is a swashplate or swashplate hydraulic pump that uses a distributor plate for oil distribution, a rotating cylinder, and a variable displacement head for flow control. The core working principle is as follows: Motion conversion: The electric motor drives the drive shaft to rotate, which in turn drives the cylinder to rotate. The piston head is always in contact with the swashplate (or swashplate). Due to the angle between the swashplate and the cylinder, the piston performs a reciprocating linear motion within the cylinder. Oil suction and discharge process: Suction stage: When the piston rotates from 0° to 180°, the piston cylinder volume increases, and liquid is drawn in through the distributor plate's suction port. Discharge stage: When the piston rotates from 180° to 360°, the piston cylinder volume decreases, and liquid is discharged through the distributor plate's outlet. Flow regulation: By changing the swashplate angle (swashplate type) or the angle between the cylinder and the drive shaft (swashplate type), the piston stroke can be adjusted to achieve flow control. A fixed angle results in a fixed displacement pump, while a variable displacement pump can be used.

[0028] Example 1 refer to Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5The axial piston pump of the present invention includes a housing 2 and a cylinder 1. The cylinder 1 is located inside the housing 2. A cylinder distribution surface 14 is provided on the outer side of the middle part of the cylinder 1. A cylinder oil hole 13 is provided on the side wall of the cylinder 1, and the cylinder oil hole 13 passes through the cylinder distribution surface 14. An oil suction port 21, an oil discharge port 22 and a distribution ring are respectively arranged on the housing 2. An oil suction port distribution groove 23 and an oil discharge port distribution groove 24 are provided on the inner side of the distribution ring. The oil suction port 21 is connected to the oil suction port distribution groove 23, the oil discharge port 22 is connected to the oil discharge port distribution groove 24, and the cylinder oil hole 13 is connected to either the oil suction port distribution groove 23 or the oil discharge port distribution groove 24.

[0029] Example 2 refer to Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 To further improve this application, the axial piston pump of the present invention includes a housing 2 and a cylinder 1. The housing 2 contains the cylinder 1, and the side of the cylinder 1 is provided with a swash plate 8 and a return plate 6. The cylinder 1 contains a piston hole, one end of the piston assembly 4 is inserted into the piston hole, and the other end of the piston assembly 4 is in contact with the swash plate 8. When the piston pump is running, the piston assembly 4 can reciprocate axially along the piston hole 12. The outer side of the middle part of the cylinder 1 is provided with a cylinder distribution surface 14, the outer diameter of which is larger than the outer diameter of both ends of the cylinder 1. The side wall of the cylinder 1 is provided with a cylinder oil hole 13, which passes through the cylinder distribution surface 14.

[0030] A front pump cover 5 is provided at one end of the housing 2, and a rear pump cover 9 is provided at the other end of the housing 2. A shaft mounting hole 12 is provided on the cylinder body 1. The drive shaft 3 passes through the front pump cover 5, the swashplate 8 and the shaft mounting hole 12 and is movably connected to the inner side of the rear pump cover 9. The cylinder body 1 rotates with the drive shaft 3 to ensure that the plunger hole 12 sucks and discharges oil.

[0031] In this embodiment, the swash plate 8 is connected to the front pump cover 5 by a first bolt, and the swash plate 8 is connected to the rear pump cover 9 by a second bolt.

[0032] In this embodiment, the housing 2 is provided with an oil suction port 21, an oil discharge port 22, and a distribution ring belt.

[0033] In this embodiment, the inner side of the distribution ring is provided with an oil suction port distribution groove 23 and an oil discharge port distribution groove 24; the oil suction port 21 is connected to the oil suction port distribution groove 23, the oil discharge port 22 is connected to the oil discharge port distribution groove 24, and the cylinder block oil hole 13 is connected to the oil suction port distribution groove 23 or the oil discharge port distribution groove 24.

[0034] In this embodiment, the diameter of the distribution ring is smaller than the diameters of both sides of the housing 2.

[0035] In this embodiment, the outer wall of the cylinder 1 and the distribution ring on the housing 2 cooperate with each other to ensure smooth oil intake and discharge.

[0036] In this embodiment, the number of cylinder oil holes 13 is the same as the number of plunger holes 12, and in order to reduce throttling losses and improve anti-cavitation capability, the diameter d1 of the cylinder oil holes 13 is equal to the diameter d of the plunger holes 12.

[0037] In this embodiment, to reduce local losses, the width b of the oil suction port distribution groove 23 and the width of the oil discharge port distribution groove 24 are equal to the diameter d1 of the cylinder block oil hole 13.

[0038] In this embodiment, to reduce local losses, the diameter d2 of the oil suction port 21 is greater than or equal to the width b of the oil suction port distribution groove 23; the diameter d3 of the oil discharge port 22 is greater than or equal to the width of the oil discharge port distribution groove 24.

[0039] In this embodiment, a bearing 7 is provided between the outer wall of the cylinder 1 and the inner wall of the housing 2 to ensure that there is no uneven wear between the cylinder 1 and the flow distribution surface 25 of the housing.

[0040] The specific working process of this invention is as follows: When the axial piston pump is working, the cylinder 1 rotates with the drive shaft 3. The piston assemblies 4 on both sides of the cylinder 1 reciprocate periodically along the piston hole 12 under the action of the swash plate 8 and the return assembly 6. Oil is sucked and discharged through the cylinder oil hole 13 of the cylinder 1, the oil suction port distribution groove 23 on the housing 2, the oil suction port 21 and the oil discharge port 22.

[0041] It should be noted that in this invention, a single displacement is divided into two parts, which share the cylinder block 1. The radial dimension of the cylinder block 1 is smaller than that of the cylinder block 1 designed with the original displacement, and the linear velocity at the outermost circle of the cylinder block 1 is significantly reduced. Under the condition that the pressure P and the material bearing capacity are constant, the cylinder block distribution surface 14 can withstand higher speeds. At the same time, the oil hole size of the cylinder block distribution surface 14 designed by the traditional design method is smaller, which leads to an increase in the flow velocity at the oil suction port 21 and a significant throttling loss. However, the cylinder block 1 designed by this invention has a flow area of ​​more than three times that of the traditional design method for the cylinder block oil hole 13, which can significantly reduce the flow velocity and improve the anti-cavitation capability.

[0042] In summary, this embodiment sufficiently demonstrates that the present invention can improve the plunger pump speed and enhance cavitation resistance; it meets practical application needs, is highly operable, and has high practical value.

[0043] This invention has the following characteristics: The external dimensions of cylinder block 1 have the most direct impact on the linear velocity of the distribution sub-distribution. Using traditional design methods, the external dimensions of cylinder block 1 can vary very little, and have virtually no impact on the linear velocity. Therefore, this invention adopts the equal division method to divide the displacement V into multiple smaller displacements in order to reduce the external dimensions of cylinder block 1, thereby reducing the linear velocity and lowering the working specific work of the distribution surface at a fixed speed.

[0044] This invention, through comprehensive consideration, divides a single displacement into two equal parts, i.e., V'=V / 2, which minimizes changes to the existing plunger pump structure and achieves the goal of increasing the rotational speed.

[0045] To ensure the displacement of the plunger pump, two plunger pumps will be connected in series using a V' design and will share cylinder 1. Therefore, the length of cylinder 1 is L = 2(L0 + S) + d + 2, where L0 is the shortest bore length of the plunger, S is the plunger stroke, and d is the plunger diameter.

[0046] Unlike traditional designs where the cylinder oil hole 13 is located at the bottom, this invention places the oil hole in the middle of the piston hole 12 in the cylinder 1.

[0047] Since this invention uses two plunger pumps connected in series and sharing a cylinder 1, the planar or spherical flow distribution of traditional plunger pumps cannot be used. Therefore, annular flow distribution is adopted.

[0048] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and disclosure of the invention. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the following claims.

[0049] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

[0050] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. An axial piston pump, characterized in that, The device includes a housing (2) and a cylinder (1). The cylinder (1) is located inside the housing (2). A cylinder distribution surface (14) is provided on the outer side of the middle part of the cylinder (1). A cylinder oil hole (13) is provided on the side wall of the cylinder (1). The cylinder oil hole (13) passes through the cylinder distribution surface (14). An oil suction port (21), an oil discharge port (22) and a distribution ring are respectively arranged on the housing (2). An oil suction port distribution groove (23) and an oil discharge port distribution groove (24) are provided on the inner side of the distribution ring. The oil suction port (21) is connected to the oil suction port distribution groove (23), the oil discharge port (22) is connected to the oil discharge port distribution groove (24), and the cylinder oil hole (13) is connected to the oil suction port distribution groove (23) or the oil discharge port distribution groove (24).

2. The axial piston pump according to claim 1, characterized in that, The outer diameter of the cylinder block distribution surface (14) is greater than the outer diameter of both ends of the cylinder block (1).

3. The axial piston pump according to claim 1, characterized in that, Both sides of the cylinder body (1) are provided with swashplates (8) and return plates (6). The cylinder body (1) is provided with plunger holes. One end of the plunger assembly (4) is inserted into the plunger hole, and the other end of the plunger assembly (4) is in contact with the swashplates (8).

4. The axial piston pump according to claim 3, characterized in that, A front pump cover (5) is provided at one end of the housing (2), and a rear pump cover (9) is provided at the other end of the housing (2). A shaft mounting hole (12) is provided on the cylinder (1). The drive shaft (3) passes through the front pump cover (5), the swashplate (8) and the shaft mounting hole (12) and is movably connected to the inside of the rear pump cover (9). The cylinder (1) rotates with the drive shaft (3).

5. The axial piston pump according to claim 4, characterized in that, The swash plate (8) is connected to the front pump cover (5) by a first bolt; the swash plate (8) is connected to the rear pump cover (9) by a second bolt.

6. The axial piston pump according to claim 1, characterized in that, A bearing (7) is provided between the outer wall of the cylinder (1) and the inner wall of the housing (2).

7. The axial piston pump according to claim 1, characterized in that, The diameter of the distribution ring is smaller than the diameters on both sides of the housing (2).

8. The axial piston pump according to claim 4, characterized in that, The number of cylinder oil holes (13) is the same as the number of plunger holes (12).

9. The axial piston pump according to claim 1, characterized in that, The width of the oil suction port distribution groove (23) and the width of the oil discharge port distribution groove (24) are equal to the diameter of the cylinder block oil hole (13).

10. The axial piston pump according to claim 1, characterized in that, The diameter of the oil suction port (21) is greater than or equal to the width of the oil suction port distribution groove (23); the diameter of the oil discharge port (22) is greater than or equal to the width of the oil discharge port distribution groove (24).

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