Axial hydraulic plunger pump

Abstract

The invention provides an axial hydraulic plunger pump which comprises a shell, a tail cover is installed at one end of the shell, and a cylinder body is fixedly installed in the shell and located on the inner end face of the tail cover. A plurality of plunger holes are formed in the cylinder body in the axial direction, a plunger is slidably installed in each plunger hole, a transmission shaft is rotationally installed in the end cover, a pressing disc is arranged on the transmission shaft, an inclined hole is formed in the end face of the pressing disc, and the center line of the inclined hole and the center line of the transmission shaft are obliquely intersected. The plunger is driven to move in the plunger hole in a reciprocating mode through the fixedly-arranged cylinder body and the non-rotating plunger structure and the swing of the swash plate, leakage points in the pump are reduced, meanwhile, the rotational inertia of the plunger pump is reduced, internal friction pairs are reduced, and the service life of the plunger pump is prolonged. The volume efficiency and the mechanical efficiency of the plunger pump are improved, the working noise is reduced, and the working temperature rise of the hydraulic pump is reduced.

Description

Technical Field

[0001] The present invention relates to the field of hydraulics, and particularly to an axial hydraulic piston pump. Background Art

[0002] An axial piston pump is a type of hydraulic pump that transports liquid through the axial movement of pistons. The main characteristics of this pump are its compact structure, uniform flow rate, and high pressure, and it is widely used in various hydraulic systems, especially in applications that require high pressure and high efficiency. Existing in-line axial piston pumps and bent-axis axial piston pumps mostly adopt fixed swash plates and distribution plates, and the structure where the cylinder block and pistons rotate. There are multiple dynamic sealing surfaces between the cylinder block and the distribution plate in the hydraulic pump, which causes relatively large internal leakage, resulting in the volumetric efficiency of the piston pump being unable to be further improved. At the same time, the rotation of the cylinder block and piston assembly has a relatively large moment of inertia, and there are multiple moving friction pairs, resulting in a relatively low mechanical efficiency of the hydraulic pump. Summary of the Invention

[0003] The technical problem to be solved by the present invention is that the existing piston pumps have relatively low volumetric efficiency and mechanical efficiency. The present invention provides an axial hydraulic piston pump to solve the above problems.

[0004] The technical solution adopted by the present invention to solve its technical problems is: an axial hydraulic piston pump, including a housing, one end of the housing is installed with a tail cover, and the other end is installed with an end cover; inside the housing, a cylinder block is fixedly installed on the inner end face of the tail cover; a plurality of piston holes are axially formed in the cylinder block, and a piston is slidably installed in each piston hole.

[0005] A transmission shaft is rotatably installed in the end cover, a pressure plate is arranged on the transmission shaft, an inclined hole is arranged on the end face of the pressure plate, and the center line of the inclined hole intersects the center line of the transmission shaft obliquely; a pressure plate bearing is installed in the inclined hole.

[0006] An inclined plate and a return spring plate are further arranged in the housing, a piston ball hole is arranged on the inclined plate, a piston ball hinge part is arranged at the outer end of the piston, and the return spring plate is fixedly installed on the end face of the inclined plate to press the piston ball hinge part into the piston ball hole; the inclined plate is fixedly installed on the inner ring of the pressure plate bearing.

[0007] An oil outlet channel is arranged on the tail cover, and a one-way valve is arranged between the oil outlet channel and the piston hole to unidirectionally connect the piston hole to the oil outlet channel, and a one-way valve is arranged on the piston hole to unidirectionally connect the inner cavity of the cylinder block to the piston hole.

[0008] Further: A spring hole is provided in the cylinder block, a spring is arranged in the spring hole, a swash plate ejector rod is inserted into the spring hole, the swash plate ejector rod is pressed against the spring, a swash plate ball hinge part is arranged at the outer end of the swash plate ejector rod, a swash plate ball hole is arranged on the swash plate end face, and the spring pushes the swash plate ejector rod to press the swash plate ball hinge part tightly in the swash plate ball hole.

[0009] Further: A main oil passage is arranged on the end cover, and the main oil passage is communicated with a plurality of the oil outlet passages.

[0010] Further: A support bearing is arranged on the end cover, and a dust-proof ring and a pressing plate are arranged on the outer side of the support bearing.

[0011] Further: The included angle formed between the center line of the inclined hole and the center line of the transmission shaft is 7.18°.

[0012] The beneficial effects of the present invention are that an axial hydraulic piston pump, through a fixed cylinder block and a non-rotating plunger structure, drives the plunger to reciprocate in the plunger hole by the swing of the swash plate, reduces the leakage points in the pump, and at the same time reduces the moment of inertia of the piston pump, reduces the internal friction pairs, improves the volumetric efficiency and mechanical efficiency of the piston pump, reduces the working noise and reduces the working temperature rise of the hydraulic pump. Description of the Drawings

[0013] The present invention will be further described below with reference to the drawings and embodiments.

[0014] Figure 1 is a schematic structural diagram of an axial hydraulic piston pump of the present invention.

[0015] In the figure, 1. housing, 2. end cover, 3. end cap, 4. cylinder block, 5. plunger hole, 6. plunger, 7. transmission shaft, 8. pressure plate, 9. inclined hole, 10. pressure plate bearing, 11. swash plate, 12. return spring plate, 13. oil outlet passage, 14. check valve, 15. spring hole, 16. spring, 17. swash plate ejector rod, 18. main oil passage, 19. support bearing, 20. dust-proof ring, 21. pressing plate. Detailed Embodiments

[0016] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation of the present invention. On the contrary, the embodiments of the present invention include all changes, modifications and equivalents falling within the spirit and scope of the appended claims.

[0017] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc. are based on the orientation or positional relationships shown in the drawings. These are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of the present invention.

[0018] In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be construed as indicating or implying relative importance. In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "connected" and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention according to specific circumstances. In addition, in the description of the present invention, unless otherwise stated, the meaning of "plurality" is two or more.

[0019] Any process or method description shown in a flowchart or described in other ways herein can be understood to represent a module, segment, or portion of code including one or more executable instructions for implementing a specific logical function or process. The scope of the preferred embodiments of the present invention includes additional implementations, where the functions can be executed in a manner that is not shown or discussed in the order, including in a substantially simultaneous manner according to the functions involved or in the reverse order, which should be understood by those skilled in the art to which the embodiments of the present invention pertain.

[0020] As Figure 1As shown in the figure, the present invention provides an axial hydraulic piston pump, which includes a housing 1. One end of the housing 1 is installed with a tail cover 2, and the other end is installed with an end cover 3. Inside the housing 1, a cylinder block 4 is fixedly installed on the inner end face of the tail cover 2. A plurality of piston holes 5 are axially formed in the cylinder block 4, and a piston 6 is slidably installed in each piston hole 5. A transmission shaft 7 is rotatably installed in the end cover 3. A pressure plate 8 is arranged on the transmission shaft 7. An inclined hole 9 is arranged on the end face of the pressure plate 8, and the center line of the inclined hole 9 intersects the center line of the transmission shaft 7 obliquely. A pressure plate bearing 10 is installed in the inclined hole 9. An inclined plate 11 and a return plate 12 are also arranged in the housing 1. A piston ball hole is arranged on the inclined plate 11. The outer end of the piston 6 is provided with a piston ball hinge part. The return plate 12 is fixedly installed on the end face of the inclined plate 11 to press the piston ball hinge part into the piston ball hole. The inclined plate 11 is fixedly installed on the inner ring of the pressure plate bearing 10. An oil outlet passage 13 is arranged on the tail cover 2. A one-way valve 14 is arranged between the oil outlet passage 13 and the piston hole 5 to unidirectionally connect the piston hole 5 to the oil outlet passage 13. A one-way valve 14 is arranged on the piston hole 5 to unidirectionally connect the inner cavity of the cylinder block 4 to the piston hole 5.

[0021] The piston 6 pump of the present application is in the form of an axial piston 6 pump, which is different from the traditional structure of pumping oil by rotating the cylinder block 4 in cooperation with a distribution disk. The present application adopts a structure in which the cylinder block 4 is fixed on the tail cover 2. The specific working process is as follows: The transmission shaft 7 starts to rotate under the drive of a driving mechanism such as a motor. The pressure plate 8 at one end of the transmission shaft 7 also rotates accordingly. Since the inclined hole 9 on the pressure plate 8 is inclined, as the pressure plate 8 rotates, the inclined plate 11 will be driven to swing in the circumferential direction under the pushing and pulling of the pressure plate bearing 10. Since the piston 6 is pressed against the end face of the inclined plate 11 by the return plate 12, the swinging inclined plate 11 will drive the piston 6 to move axially, and perform the work of oil suction and pumping in the piston hole 5.

[0022] When the piston 6 withdraws from the piston hole 5, the one-way valve 14 between the oil outlet passage 13 and the piston hole 5 closes, and the one-way valve 14 between the piston hole 5 and the inner cavity of the cylinder block 4 opens. In this way, the hydraulic oil in the inner cavity of the cylinder block 4 can be sucked into the piston hole 5 to complete the oil suction. When the piston 6 enters the piston hole 5, the one-way valve 14 between the oil outlet passage 13 and the piston hole 5 opens, and the one-way valve 14 between the piston hole 5 and the inner cavity of the cylinder block 4 closes. The piston 6 pumps the hydraulic oil in the piston hole 5 into the oil outlet passage 13 to complete the pumping operation.

[0023] In this application, the inclination angle of the swash plate 11 is used to change the stroke of the plunger 6. The rotational motion is transmitted through the pressure plate bearing 10 and converted into a linear reciprocating motion, and in cooperation with the two-way check valve 14, continuous hydraulic oil delivery and pressure establishment are achieved. Compared with the axial piston 6 pump of the prior art, the cylinder block 4 and the plunger 6 of this application do not rotate, only the plunger 6 makes a reciprocating motion. Compared with the plunger pump of the prior art, the moment of inertia of the rotating components is smaller. On the one hand, the moving friction pairs are reduced, heat generation or wear inside the pump is avoided, and the mechanical efficiency is improved. On the other hand, the internal leakage points between the cylinder block 4 and the valve plate and between the slipper and the swash plate 11 plane are eliminated, improving the volumetric efficiency of the plunger 6 pump. Especially under high-pressure conditions, the improvement of the volumetric efficiency is particularly obvious.

[0024] A spring hole 15 is provided in the cylinder block 4. A spring 16 is provided in the spring hole 15. A swash plate ejector rod 17 is inserted into the spring hole 15. The swash plate ejector rod 17 is pressed against the spring 16. An outer end of the swash plate ejector rod 17 is provided with a swash plate ball hinge portion. A swash plate ball hole is provided on the end face of the swash plate 11. The spring 16 pushes the swash plate ejector rod 17 to press the swash plate ball hinge portion tightly in the swash plate ball hole.

[0025] In the cylinder block 4, the swash plate ejector rod 17 is ball-hinged with the swash plate 11 by the spring 16 to form an elastic pre-tightening force, so that the swash plate 11 can be closely attached to the pressure plate 8, realizing a dynamic clearance compensation mechanism among the plunger 6, the swash plate 11, and the pressure plate 8. At the same time, the spring 16 continuously applies a force perpendicular to the swash plate ball hole to the swash plate 11 through the swash plate ejector rod 17, offsetting the vibration and inclination caused by oil pressure fluctuations during the operation of the swash plate 11, which helps to reduce noise, reduce jitter, increase the maximum rotational speed of the plunger 6 pump, and extend the service life of the bearing.

[0026] A main oil passage 18 is provided on the end cap 2. The main oil passage 18 communicates with a plurality of the oil outlet passages 13. The oil outlet passages 13 on a plurality of plunger holes 5 are merged through the main oil passage 18, reducing the energy loss caused by local eddies.

[0027] A support bearing 19 is provided on the end cover 3. A dust-proof ring 20 and a pressing plate 21 are provided outside the support bearing 19. The support bearing improves the rotational stability of the transmission shaft 7, reduces the vibration and noise during the operation of the plunger 6 pump, and improves the axial load-bearing capacity of the transmission shaft 7, making the plunger 6 pump suitable for operation under high-pressure conditions.

[0028] The included angle formed between the center line of the inclined hole 9 and the center line of the transmission shaft 7 is 7.18°. This angle is the optimal inclination angle, which can balance the displacement efficiency and mechanical shock, optimize the commutation impact force of the plunger 6, and maximize the volumetric efficiency of the plunger 6 pump at the rated rotational speed.

[0029] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0030] Taking the above-mentioned ideal embodiments of the present invention as an inspiration, through the above description, relevant staff can completely make various changes and modifications without departing from the technical idea of this invention. The technical scope of this invention is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. An axial hydraulic piston pump, characterized in that: The invention comprises a housing (1), wherein a tail cover (2) is mounted on one end of the housing (1), and an end cover (3) is mounted on the other end; a cylinder body (4) is fixedly mounted on the inner end surface of the tail cover (2) in the housing (1); a plurality of plunger holes (5) are axially formed on the cylinder body (4), and a plunger (6) is slidably mounted in each of the plunger holes (5); A transmission shaft (7) is rotatably mounted in the end cover (3); a pressure plate (8) is arranged on the transmission shaft (7); an inclined hole (9) is arranged on the end surface of the pressure plate (8); a center line of the inclined hole (9) is arranged to obliquely intersect with the center line of the transmission shaft (7); a pressure plate bearing (10) is installed in the inclined hole (9); A swash plate (11) and a return plate (12) are also provided in the housing (1); a plunger ball hole is provided on the swash plate (11); a plunger ball hinge is provided at the outer end of the plunger (6); the return plate (12) is fixedly mounted on the end surface of the swash plate (11) so that the plunger ball hinge is pressed into the plunger ball hole; the swash plate (11) is fixedly mounted on the inner ring of the pressure plate bearing (10); The tail cover (2) is provided with an oil outlet passage (13), a one-way valve (14) is provided between the oil outlet passage (13) and the plunger hole (5) to connect the plunger hole (5) to the oil outlet passage (13) in one-way manner, and a one-way valve (14) is provided on the plunger hole (5) to connect the inner cavity of the cylinder body (4) to the plunger hole (5) in one-way manner.

2. An axial hydraulic piston pump according to claim 1, characterized in that: A spring hole (15) is provided in the cylinder body (4), a spring (16) is provided in the spring hole (15), a swash plate push rod (17) is inserted into the spring hole (15), the swash plate push rod (17) is pressed against the spring (16), a swash plate ball joint is provided at the outer end of the swash plate push rod (17), a swash plate ball hole is provided on the end surface of the swash plate (11), and the spring (16) pushes the swash plate push rod (17) to press the swash plate ball joint against the swash plate ball hole.

3. An axial hydraulic piston pump according to claim 2, characterized in that: The tail cover (2) is provided with a main oil passage (18), and the main oil passage (18) is connected to a plurality of the oil outlet passages (13).

4. An axial hydraulic piston pump according to claim 3, characterized in that: A support bearing (19) is provided on the end cover (3), and a dust ring (20) and a pressure plate (21) are provided on the outer side of the support bearing (19).

5. An axial hydraulic piston pump according to claim 4, characterized in that: The angle formed between the center line of the inclined hole (9) and the center line of the transmission shaft (7) is 7.18°.

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