An axial piston pump

Abstract

The present application relates to the technical field of hydraulic pressure, in particular to an axial piston pump. The axial piston pump comprises: a disc body of a distribution disc unit, which is provided with 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 that of the oil suction port. The outer diameter of the oil discharge port is equal to that of the oil suction port. A support layer is fixedly connected with the disc body. The support layer of the distribution disc unit is provided with an oil discharge groove and an oil suction groove. The oil discharge groove is in communication with the oil discharge port. The oil discharge groove is arc-shaped and concentrically arranged with the oil discharge port. The inner diameter of the oil discharge groove is smaller than that of the oil discharge port. The outer diameter of the oil discharge groove is equal to that of the oil discharge port. The oil suction groove is in communication with the oil suction port. The oil suction groove is arc-shaped and concentrically arranged with the oil suction port. The outer diameter of the oil suction groove is greater than that of the oil suction port. The inner diameter of the oil suction groove is equal to that of the oil suction port. In this way, the problem of how to improve the overturning resistance of the piston pump cylinder under extreme working conditions is solved.

Description

Technical Field

[0001] This invention relates to the field of hydraulic technology, and more specifically, to an axial piston pump. Background Technology

[0002] Axial piston pumps in distributed hydraulic systems are positive displacement hydraulic pumps widely used in aircraft hydraulic systems. They utilize the volume changes of series and parallel chambers to build pressure and transfer flow, realizing the conversion of mechanical energy from the aircraft casing to hydraulic energy. The entire rotating assembly is immersed in the hydraulic oil in the housing. The main shaft drives the cylinder to rotate through a spline connection, causing the slipper to slide on the swashplate, forcing the piston to reciprocate periodically within the cylinder, thus achieving continuous oil suction and discharge of the piston pump.

[0003] Axial hydraulic piston pumps are the core power components of electro-hydraulic actuators, characterized by their compact structure, small size, and high power density. Given the extreme weight reduction requirements of aircraft, further increasing the rotational speed is a major research direction for achieving high power density and miniaturization in electro-hydraulic actuators. However, cylinder overturning caused by high speeds presents significant challenges to the structural design of axial piston pumps. Abnormal wear caused by slipper overturning under high-speed conditions is a major cause of slipper failure, and the large overturning moment at high speeds can easily lead to drive shaft overturning and deformation. Current research primarily focuses on low-speed conditions, lacking analysis of the impact of ultra-high-speed conditions on axial piston pump friction pair damage and rotating component overturning. Furthermore, design results from low-speed conditions are not entirely applicable to high-speed axial piston pump design. Therefore, it is necessary to improve and optimize the traditional low-speed axial piston pump structure to meet the requirements of extreme operating conditions. Summary of the Invention

[0004] To address the problem of improving the anti-overturning capability of a piston pump cylinder under extreme operating conditions, this invention provides an axial piston pump, comprising:

[0005] Housing unit;

[0006] A distribution plate unit is located within the outer casing unit. The distribution plate unit includes a plate body and a support layer. The plate body has an oil drain port and an oil suction port. Both the oil drain port and the oil suction port are arc-shaped and concentrically arranged. The inner diameter of the oil drain port is equal to the inner diameter of the oil suction port. The outer diameter of the oil drain 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. The oil drain groove communicates with the oil drain port. The oil drain groove is arc-shaped. Furthermore, it is 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; the 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 outer diameter of the oil suction port; the inner diameter of the oil suction groove is equal to the inner diameter of the oil suction port.

[0007] A cylinder block unit is located inside the outer shell unit; one end of the cylinder block unit is attached to the support layer; the cylinder block unit is rotatably connected to the outer shell unit; the cylinder block unit includes a cylinder body, which has multiple plunger cavities.

[0008] A plunger unit, comprising multiple plunger units, each plunger unit including a plunger rod and a plunger ball head; the plunger rod is slidably connected to the cylinder block unit; the plunger rod and the plunger cavity are correspondingly arranged one-to-one; the plunger rod is slidably disposed within the plunger cavity; the plunger ball head is integrally formed with the plunger rod;

[0009] A sliding shoe unit, wherein the sliding shoe unit is detachably connected to the plunger ball head;

[0010] 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;

[0011] A drive shaft unit that drives the cylinder block unit to rotate;

[0012] A central spring unit drives the slipper unit to press against the swashplate unit.

[0013] In some embodiments, the cylinder block unit and the distributor plate unit form a distributor pair; the distributor pair is located in the high-pressure zone at the location of the oil drain groove; the distributor pair is located in the low-pressure zone at the location of the oil suction groove.

[0014] The inner radius of the oil drain groove is a first radius r1′; the inner radius of the oil drain port is a second radius r2′; the outer radius of the oil suction port is a third radius r3′; the outer radius of the oil suction groove is a fourth radius r4′; the difference between the first radius and the second radius is a first offset δ1 value; the difference between the third radius and the fourth radius is a second offset δ2 value; the first offset value and the second offset value are related to the following formula:

[0015] M sx +M tx +M vx +M sh =0;

[0016]

[0017] Among them, M sx M is the non-inertial overturning moment generated by the force exerted by the swashplate unit on the piston rod in the reference direction on the cylinder block unit; the reference direction is the direction from the center of the drain groove to the middle of the drain groove; M tx M is the inertial force and overturning moment generated by the inertial force of the piston rod movement on the cylinder block unit; vx M is the total overturning moment generated by the oil film of the distribution pair on the cylinder block unit, and is equal to the sum of the overturning moments generated by the oil films in the high-pressure and low-pressure regions of the distribution pair on the cylinder block unit; sh The torque generated by the drive shaft unit on the cylinder block unit in the reference direction; r p L is the radius of the cylinder block unit; c β is the distance from the intersection of the swashplate unit and the drive shaft unit to the distribution plate unit; β is the tilt angle of the swashplate unit. The pressure in the i-th plunger cavity; the circle formed by the distribution of the multiple plunger units is a distribution circle; R is the radius of the distribution circle; F represents the angular displacement of the i-th plunger rod; sp This is the preload force of the central spring unit.

[0018] In some embodiments, the inertial force of the piston rod movement on the cylinder block unit, resulting in an overturning moment, is calculated according to the following formula:

[0019]

[0020] Where N is the number of plunger units; ω is the angular velocity.

[0021] In some embodiments, the first offset value is also related to the following formula:

[0022]

[0023] Among them, M vHx When the first offset value is zero, the overturning moment generated by the oil film in the high-pressure zone of the distribution sub on the cylinder block unit; θ1 is the starting angle of the high-pressure zone of the distribution sub; θ2 is the ending angle of the high-pressure zone of the distribution sub; p H R1 is the load pressure; R2 is the inner radius of the inner sealing strip of the distribution pair; R3 is the inner radius of the outer sealing strip of the distribution pair; R4 is the outer radius of the outer sealing strip of the distribution pair; R1 ′ =r1;r2 ′ =r2-δ1;r3 ′ =r3+δ2;r4 ′ =r4.

[0024] In some embodiments, the first offset value is calculated according to the following formula:

[0025]

[0026] Among them, M vHx′ When the first offset value is greater than zero, the overturning moment generated by the oil film in the high-pressure zone of the distribution sub on the cylinder block unit; δ1 is the first offset value.

[0027] In some embodiments, the second offset value is also related to the following formula:

[0028]

[0029] Among them, M vLx′ θ3 is the overturning moment generated by the oil film in the low-pressure zone of the distribution sub on the cylinder block unit; θ4 is the starting angle of the low-pressure zone of the distribution sub; p L The overturning force exerted on the cylinder unit by the oil film formed between the oil suction groove and the cylinder unit.

[0030] In some embodiments, the axial piston pump further includes a valve unit, which includes a valve core body and a valve core spring; the valve unit is detachably connected to the distribution plate; the valve unit controls the opening and closing of the oil discharge port and the oil suction port with the piston cavity, respectively;

[0031] The calculation process for the first offset value and the second offset value is also related to the following formula:

[0032]

[0033] Among them, L s F is the axial length of the contact area between the cylinder block unit and the drive shaft; v F is the thrust of the valve core body;sp This is the preload force of the valve core spring.

[0034] In some embodiments, the absolute value of the first offset value is less than the absolute value of the second offset value.

[0035] In some embodiments, the depth of the oil drain groove is less than the depth of the oil drain port; the depth of the oil suction groove is less than the depth of the oil suction port; and the depth directions of the oil drain groove, the oil drain port, the oil suction groove, and the oil suction port are perpendicular to the disc body.

[0036] In some embodiments, the support layer and the disk body are integrally formed by 3D printing.

[0037] To address the problem of improving the anti-overturning capability of piston pump cylinders under extreme operating conditions, this invention offers the following advantages:

[0038] By appropriately altering the offset dimensions of the oil drain groove and oil suction groove on the support layer, the inner diameter of the oil drain groove is made smaller than the inner diameter of the oil drain port, and the outer diameter of the oil suction groove is made larger than the outer diameter of the oil suction port. This changes the instantaneous torque exerted by the support layer of the distribution plate unit on the cylinder block unit, achieving a balanced design of the cylinder block unit's overturning moment. This reduces the lateral displacement of the cylinder block unit under high-speed operation of the axial piston pump, improving the reliability of the axial piston pump. Attached Figure Description

[0039] Figure 1 A schematic diagram of an axial piston pump according to one embodiment is shown;

[0040] Figure 2 A three-dimensional schematic diagram of a distribution disk unit according to one embodiment is shown;

[0041] Figure 3 It shows Figure 2 A schematic diagram of the distribution disk unit in the embodiment;

[0042] Figure 4 It shows Figure 2 A schematic cross-sectional view of the distribution plate unit in the embodiment;

[0043] Figure 5 A simulation diagram of an axial piston pump before improvement is shown in one embodiment;

[0044] Figure 6 A simulation diagram of an improved axial piston pump according to one embodiment is shown.

[0045] Reference numerals: 10 Housing unit; 20 Distribution plate unit; 21 Plate body; 22 Support layer; 23 Oil suction port; 24 Oil discharge port; 25 Oil suction groove; 26 Oil discharge groove; 30 Cylinder block unit; 31 Cylinder block body; 32 Plunger cavity; 40 Plunger unit; 41 Plunger rod; 42 Plunger ball head; 50 Slipper shoe unit; 60 Swashplate unit; 70 Drive shaft unit; 80 Center spring unit. Detailed Implementation

[0046] The present disclosure will now be discussed with reference to several exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and thus implement the present disclosure, and are not intended to imply any limitation on the scope of the disclosure.

[0047] As used herein, the term "comprising" and its variations are to be interpreted as open-ended terms meaning "including but not limited to". The term "based on" is to be interpreted as "at least partially based on". The terms "one embodiment" and "an embodiment" are to be interpreted as "at least one embodiment". The term "another embodiment" is to be interpreted as "at least one other embodiment". The terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "vertical", "horizontal", "lateral", "longitudinal", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments and are not intended to limit the indicated devices, elements, or components to having a specific orientation or being constructed and operated in a specific orientation. Furthermore, some of the above terms may be used to indicate other meanings besides orientations or positional relationships; for example, the term "upper" may in some cases indicate a dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application according to the specific circumstances. In addition, the terms "installed", "set up", "equipped with", "connected", and "linked" should be interpreted broadly. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, elements, or components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances. Furthermore, the terms "first," "second," etc., are mainly used to distinguish different devices, elements, or components (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance or quantity of the indicated devices, elements, or components. Unless otherwise stated, "a plurality of" means two or more.

[0048] In this embodiment, the cylinder overturning caused by the high speed of the axial piston pump under high-speed operation poses a significant challenge to the structural design of the axial piston pump. Abnormal wear caused by slipper overturning under high-speed conditions is a major cause of slipper failure. Furthermore, when the axial piston pump speed exceeds 10,000 rpm, the inertial overturning torque of the cylinder is comparable to the counter-thrust torque of the distribution plate oil film. At this point, the cylinder is highly prone to overturning and deforming towards the outer dead point of the distribution plate, limiting the high-speed application of electro-hydraulic actuators. To solve the above problems, this embodiment discloses an axial piston pump. Figure 1 As shown, the axial piston pump includes: housing unit 10, distribution plate unit 20, cylinder block unit 30, piston unit 40, slipper unit 50, swashplate unit 60, drive shaft unit 70, and center spring unit 80.

[0049] The housing unit 10 serves as the housing of the axial piston pump, protecting the internal components of the axial piston pump and preventing oil leakage and the entry of external foreign objects.

[0050] Distribution plate unit 20 is located inside housing unit 10; such as Figure 2 , Figure 3 , Figure 4 As shown, the distribution plate unit 20 includes a plate body 21 and a support layer 22. The plate body 21 has an oil drain port 24 and an oil suction port 23. Both the oil drain port 24 and the oil suction port 23 are arc-shaped and concentrically arranged. The inner diameter of the oil drain port 24 is equal to the inner diameter of the oil suction port 23. The outer diameter of the oil drain port 24 is equal to the outer diameter of the oil suction port 23. The support layer 22 is fixedly connected to the plate body 21. The support layer 22 has an oil drain groove 26 and an oil suction groove 25. The oil drain groove 26 communicates with the oil drain port 24. The oil drain groove 26 is arc-shaped and concentrically arranged with the oil drain port 24. The central angle of the oil drain port 24 coincides with the central angle of the oil drain groove 26. The inner diameter of the oil drain groove 26 is smaller than the inner diameter of the oil drain port 24. The outer diameter of the oil drain groove 26 is equal to the outer diameter of the oil drain port 24. The oil suction groove 25 communicates with the oil suction port 23. The oil suction groove 25 is arc-shaped and... The oil suction port 23 and the oil discharge port 26 are concentrically arranged; the central angle of the oil suction port 23 coincides with the central angle of the oil suction groove 25; the outer diameter of the oil suction groove 25 is larger than the outer diameter of the oil suction port 23; the inner diameter of the oil suction groove 25 is equal to the inner diameter of the oil suction port 23. Through the above arrangement, the oil suction groove 25 and the oil discharge groove 26 are offset from the oil suction port 23 and the oil discharge port 24, respectively. When an oil film is formed between the support layer 22 and the cylinder block unit 30, the oil film around the oil discharge groove 26 is closer to the center of the distribution plate unit 20, and the oil film around the oil suction groove 25 is farther away from the center of the distribution plate unit 20. This balances the uniformity of the overturning moment of the distribution auxiliary oil film at the support layer 22 on the cylinder block unit 30, thereby reducing the lateral displacement of the cylinder block unit 30 under high-speed operation of the axial piston pump and improving the reliability of the axial piston pump.

[0051] The cylinder unit 30 is located inside the outer shell unit 10; one end of the cylinder unit 30 is attached to the support layer 22; the cylinder unit 30 is rotatably connected to the outer shell unit 10; the cylinder unit 30 includes a cylinder body 31, which has multiple plunger chambers 32; the hydraulic function of the axial plunger pump is realized by the piston movement of the plunger unit 40 in the plunger chambers 32 of the cylinder body 31.

[0052] There are multiple plunger units 40, each including a plunger rod 41 and a plunger ball head 42. The plunger rod 41 is slidably connected to the cylinder block unit 30. The plunger rod 41 and the plunger cavity 32 are arranged in a one-to-one correspondence. The plunger rod 41 is slidably arranged in the plunger cavity 32. The plunger ball head 42 is integrally formed with the plunger rod 41. The piston moves in the plunger cavity 32 through the plunger unit 40, and cooperates with the distribution plate unit 20 to realize the oil suction and oil discharge operations.

[0053] The slipper unit 50 is detachably connected to the plunger ball head 42; the swashplate unit 60 is located inside the housing unit 10; the swashplate unit 60 is detachably connected to the housing unit 10; the slipper unit 50 abuts against the swashplate unit 60; the drive shaft unit 70 drives the cylinder unit 30 to rotate; the center spring unit 80 drives the slipper unit 50 to press against the swashplate unit 60.

[0054] In this embodiment, as Figure 5 , Figure 6 As shown, based on the establishment of a mathematical model of the cylinder block under the combined action of inertial overturning moment and hydraulic overturning moment of the axial piston pump, the motion law characteristics of the axial piston pump are analyzed, revealing the cylinder block overturning bearing mechanism under complex loads. Among them, Figure 5 The results can be obtained by substituting the original structural parameters from Table 1 below into simulation software. Figure 6 The results can be obtained by substituting the structural optimization parameters in Table 1 below into simulation software. Figure 5 The image shows the tendency of an axial piston pump to overturn under its original structural parameters and the direction of its overturning motion. Figure 5 and Figure 6 The colors in the image, arranged in the order of red, orange, yellow, green, cyan, and blue, illustrate the mechanism by which the deformation of the axial piston pump decreases from large to small. Figure 6 The axial piston pump in this design exhibits strong anti-tipping capability after structural optimization. Specifically, during the rotation of the cylinder block unit 30 relative to the distribution plate unit 20, the piston chamber 32 of the cylinder block unit 30 will successively experience contact, overlap, and separation with the oil suction groove 25 and the oil discharge groove 26. During this process, the effective wrap angle range of the distribution pair and the size of the sealing band will change accordingly. By reasonably changing the first and second offset values, the instantaneous torque exerted by the distribution pair oil film on the cylinder block unit 30 can be altered, achieving a balanced design of the cylinder block overturning torque, thereby reducing the lateral displacement of the cylinder block at ultra-high speeds.

[0055]

[0056] like Figure 1 As shown, the cylinder block unit 30 and the distributor plate unit 20 form a distributor pair; as Figure 2 As shown, the distribution pair is located in the high-pressure zone at the oil discharge trough 26; the distribution pair is located in the low-pressure zone at the oil suction trough 25.

[0057] like Figure 3 As shown, the inner radius of the oil drain groove 26 is the first radius r1′; the inner radius of the oil drain port 24 is the second radius r2′; the outer radius of the oil suction port 23 is the third radius r3′; the outer radius of the oil suction groove 25 is the fourth radius r4′; the difference between the first radius and the second radius is the first offset value δ1; the difference between the third radius and the fourth radius is the second offset value δ2. The first offset value and the second offset value are related to the following formula:

[0058] M sx +M tx +M vx +M sh =0;

[0059]

[0060] Among them, M sx M is the non-inertial overturning moment generated on the cylinder block unit 30 by the force exerted by the swashplate unit 60 on the plunger rod 41 in the reference direction; the reference direction is the direction from the center of the drain groove 26 to the middle of the drain groove 26; tx M is the inertial force of the piston rod 41 moving on the cylinder block unit 30, which generates an overturning moment; vx The total overturning moment generated by the oil film of the distribution pair on the cylinder block unit 30 is equal to the sum of the overturning moments generated by the oil films in the high-pressure and low-pressure regions of the distribution pair on the cylinder block unit 30, that is: M vx =M vHx +M vLx M sh M is the torque generated by the drive shaft unit 70 on the cylinder block unit 30 in the reference direction. sh The value can be obtained from the above torque balance equation (i.e., M). sx +M tx +M vx +M sh =0) It is concluded that by adjusting the first offset value and the second offset value, M can be reduced. sh The effect of this value can improve the anti-overturning moment capability of the plunger pump cylinder under extreme operating conditions. p L is the radius of cylinder block unit 30; c β is the distance from the intersection of the swashplate unit 60 and the drive shaft unit 70 to the distribution plate unit 20; β is the tilt angle of the swashplate unit 60. The pressure in the i-th plunger cavity 32 is denoted as ; the circle formed by the distribution of multiple plunger units 40 is called the distribution circle; R is the radius of the distribution circle. F represents the angular displacement of the i-th plunger rod 41; sp The preload of the central spring unit 80 is given. The non-inertial overturning moment M generated by the force exerted by the swashplate unit 60 on the piston rod 41 on the cylinder block unit 30 in the reference direction, calculated above, is obtained. sx This facilitates the subsequent determination of the offset dimensions of the oil drain trough 26 and the oil suction trough 25, namely the first offset value and the second offset value.

[0061] In this embodiment, the inertial force of the piston rod 41 on the cylinder block unit 30 and the resulting overturning moment are calculated according to the following formula:

[0062]

[0063] Among them, M tx The inertial force of the piston rod 41 on the cylinder block unit 30 represents the overturning moment; N is the number of piston units 40; and ω is the angular velocity. Through the above calculations, the overturning moment of the inertial force of the piston rod 41 on the cylinder block unit 30 can be obtained, thereby further improving the analysis of the motion characteristics of the axial piston pump and revealing the overturning bearing mechanism of the cylinder block unit 30 under complex loads.

[0064] In this embodiment, the first offset value is also related to the following formula:

[0065]

[0066] Among them, M vHx When the first offset value is zero, the overturning moment generated by the oil film in the high-pressure zone of the distribution sub on the cylinder block unit 30; θ1 is the starting angle of the high-pressure zone of the distribution sub; θ2 is the ending angle of the high-pressure zone of the distribution sub; p H R1 is the load pressure; R2 is the inner radius of the inner sealing strip of the distribution pair; R3 is the inner radius of the outer sealing strip of the distribution pair; R4 is the outer radius of the outer sealing strip of the distribution pair; R1 ′ =r1;r2 ′ =r2-δ1;r3 ′ =r3+δ2;r4 ′ =r4.

[0067] Since the cylinder block unit 30 is subjected to the torque of the oil film of the distribution sub in addition to the torque of the piston unit 40 and the swash plate unit 60, the overturning torque generated by the oil film in the high-pressure zone of the distribution sub on the cylinder block unit 30 when the first offset value is zero can be obtained through the above calculation, which can improve the reliability of the analysis and calculation of the overturning torque of the axial piston pump.

[0068] In this embodiment, the first offset value is calculated according to the following formula:

[0069]

[0070] Among them, M vHx′ When the first offset value is greater than zero, the overturning moment generated by the oil film in the high-pressure zone of the distribution sub on the cylinder block unit 30; δ1 is the first offset value.

[0071] The above calculations facilitate the determination of the first offset value. During the rotation of the cylinder block unit 30 relative to the distribution plate unit 20, the oil suction groove 25 and oil discharge groove 26 on the support layer 22 will successively contact, overlap and separate from the plunger cavity 32. During this process, the effective wrap angle range of the distribution pair and the size of the formed oil film sealing band will change accordingly. By reasonably changing the offset size of the support layer 22, the instantaneous torque of the distribution pair oil film on the cylinder block unit 30 can be changed, realizing the balanced design of the overturning torque of the cylinder block unit 30, thereby reducing the lateral offset of the cylinder block unit 30 at ultra-high speed.

[0072] In this embodiment, the second offset value is also related to the following formula:

[0073]

[0074] Among them, M vLx′ θ3 is the overturning moment generated by the oil film in the low-pressure zone of the distribution pair on the cylinder block unit 30; θ4 is the starting angle of the low-pressure zone of the distribution pair; p L The overturning force of the oil film formed between the oil suction groove 25 and the cylinder unit 30 on the cylinder unit 30.

[0075] When the distribution sub-seal strip shifts, the first shift value δ1 can be the shift amount in the high-pressure zone of the distribution sub-seal, and the second shift value δ2 can be the shift amount in the low-pressure zone of the distribution sub-seal, thus yielding r1. ′ =r1;r2 ′ =r2-δ1;r3 ′ =r3+δ2;r4 ′ =r4. The cylinder block unit 30 is mainly subjected to the force of the oil film from the distribution pair on its end face. The pressure distribution in the high-pressure zone of the distribution pair is as follows:

[0076]

[0077] The pressure distribution in the low-pressure region of the distribution sub is as follows:

[0078]

[0079] Then, by performing an area integral on the pressure distribution in the high-pressure and low-pressure regions of the distribution sub-assembly, the torque exerted by the oil film of the distribution sub-assembly on the cylinder block unit 30 can be obtained. First, the pressure distribution in the high-pressure region can be performed by an area integral:

[0080]

[0081] Then, by integrating the contents within the curly braces using the method of integration by parts and summing the results, we obtain:

[0082]

[0083] Then, using the trigonometric sum-to-product formula, further integration yields the torque:

[0084]

[0085] Thus, the moment equation for the high-pressure region of the distribution sub-phase is obtained. The moment equation for the low-pressure region is obtained by referring to the above process and solving the surface integral based on the pressure distribution in the low-pressure region:

[0086]

[0087] The above calculations facilitate the determination of the first and second offset values. Therefore, the total overturning moment generated by the oil film of the distribution pair on the cylinder block unit 30 can be derived as follows:

[0088]

[0089] As shown in the above formula, by changing the magnitude of the first offset value and the second offset value, the total overturning moment generated by the oil film of the distribution pair on the cylinder block unit 30 can be changed. This allows for alteration of the instantaneous torque exerted by the support layer 22 of the distribution plate unit 20 on the cylinder block unit 30, achieving a balanced design of the overturning moment of the cylinder block unit 30. This reduces the lateral displacement of the cylinder block unit 30 under high-speed operation of the axial piston pump, thereby improving the reliability of the axial piston pump.

[0090] In this embodiment, the axial piston pump also includes a valve unit, which includes a valve core body and a valve core spring; the valve unit is detachably connected to the distribution plate; the valve unit controls the opening and closing of the oil discharge port 24 and the oil suction port 23 with the piston cavity 32 respectively;

[0091] The calculation process for the first and second offset values ​​is also related to the following formula:

[0092]

[0093] Among them, L s F is the axial length of the contact area between the cylinder block unit 30 and the drive shaft; v The thrust of the valve core body; F spThis is the preload force of the valve core spring. The calculation takes into account the torque generated by the drive shaft unit 70, thereby improving the accuracy of the calculated first and second offset values.

[0094] In this embodiment, as Figure 4 As shown, the absolute value of the first offset is less than the absolute value of the second offset. Since one end of the drive shaft unit 70 passes through the center of the distribution plate unit 20, the inner diameter side of the oil drain groove 26 needs to be offset towards the center of the support layer 22, which limits the offset distance of the inner diameter of the oil drain groove 26, while the outer diameter offset distance of the oil suction groove 25 is sufficient. This design can make reasonable use of the space on the support layer 22 and avoid affecting the oil film sealing effect between the support layer 22 and the cylinder block unit 30.

[0095] In this embodiment, as Figure 4 As shown, the depth of the oil drain groove 26 is less than the depth of the oil drain port 24; the depth of the oil suction groove 25 is less than the depth of the oil suction port 23; the depth directions of the oil drain groove 26, oil drain port 24, oil suction groove 25, and oil suction port 23 are perpendicular to the disc body 21. This reduces production costs, as a thinner thickness is sufficient to achieve the effect of changing the oil film offset dimensions on the inner and outer diameter sides of the oil drain groove 26 and the inner and outer diameter sides of the oil suction groove 25.

[0096] In this embodiment, the support layer 22 and the disk body 21 can be integrally formed by 3D printing. The 3D printed distribution disk unit 20 has high precision, and the support layer 22 and the disk body 21 are firmly bonded together.

[0097] Those skilled in the art will understand that the above embodiments are specific examples of implementing this disclosure, and in practical applications, various changes can be made in form and detail without departing from the scope of this disclosure.

Claims

1. An axial piston pump, characterized in that, The axial piston pump includes: Housing unit; A distribution plate unit is located within the outer casing unit. The distribution plate unit includes a plate body and a support layer. The plate body has an oil drain port and an oil suction port. Both the oil drain port and the oil suction port are arc-shaped and concentrically arranged. The inner diameter of the oil drain port is equal to the inner diameter of the oil suction port. The outer diameter of the oil drain 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. The oil drain groove communicates with the oil drain port. The oil drain groove is arc-shaped. Furthermore, it is 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; the 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 outer diameter of the oil suction port; the inner diameter of the oil suction groove is equal to the inner diameter of the oil suction port. A cylinder block unit is located inside the outer shell unit; one end of the cylinder block unit is attached to the support layer; the cylinder block unit is rotatably connected to the outer shell unit; the cylinder block unit includes a cylinder body, which has multiple plunger cavities. A plunger unit, comprising multiple plunger units, each plunger unit including a plunger rod and a plunger ball head; the plunger rod is slidably connected to the cylinder block unit; the plunger rod and the plunger cavity are correspondingly arranged one-to-one; the plunger rod is slidably disposed within the plunger cavity; the plunger ball head is integrally formed with the plunger rod; A sliding shoe unit, wherein the sliding shoe 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 that drives the cylinder block unit to rotate; A central spring unit drives the slipper unit to press against the swashplate unit.

2. An axial piston pump according to claim 1, characterized in that, The cylinder block unit and the distributor plate unit form a distributor pair; the distributor pair is located in the high-pressure zone at the location of the oil drain groove; the distributor pair is located in the low-pressure zone at the location of the oil suction groove; The inner radius of the oil drain groove is a first radius r1′; the inner radius of the oil drain port is a second radius r2′; the outer radius of the oil suction port is a third radius r3′; the outer radius of the oil suction groove is a fourth radius r4′; the difference between the first radius and the second radius is a first offset value δ1; the difference between the third radius and the fourth radius is a second offset value δ2; the first offset value and the second offset value are related to the following formula: M sx +M tx +M vx +M sh =0; Among them, M sx M is the non-inertial overturning moment generated by the force exerted by the swashplate unit on the piston rod in the reference direction on the cylinder block unit; the reference direction is the direction from the center of the drain groove to the middle of the drain groove; M tx M is the inertial force and overturning moment generated by the inertial force of the piston rod movement on the cylinder block unit; vx M is the total overturning moment generated by the oil film of the distribution pair on the cylinder block unit, and is equal to the sum of the overturning moments generated by the oil films in the high-pressure and low-pressure regions of the distribution pair on the cylinder block unit; sh The torque generated by the drive shaft unit on the cylinder block unit in the reference direction; r p L is the radius of the cylinder block unit; c β is the distance from the intersection of the swashplate unit and the drive shaft unit to the distribution plate unit; β is the tilt angle of the swashplate unit. The pressure in the i-th plunger cavity; the circle formed by the distribution of the multiple plunger units is a distribution circle; R is the radius of the distribution circle; F represents the angular displacement of the i-th plunger rod; sp This is the preload force of the central spring unit.

3. An axial piston pump according to claim 2, characterized in that, The inertial force of the piston rod's motion, which generates an inertial force on the cylinder block unit, and the resulting overturning moment, are calculated using the following formula: Where N is the number of plunger units; ω is the angular velocity.

4. An axial piston pump according to claim 3, characterized in that, The first offset value is also related to the following formula: Among them, M vHx When the first offset value is zero, the overturning moment generated by the oil film in the high-pressure zone of the distribution sub on the cylinder block unit; θ1 is the starting angle of the high-pressure zone of the distribution sub; θ2 is the ending angle of the high-pressure zone of the distribution sub; p H R1 is the load pressure; R2 is the inner radius of the inner sealing strip of the distribution pair; R3 is the inner radius of the outer sealing strip of the distribution pair; R4 is the outer radius of the outer sealing strip of the distribution pair; R1 ′ =r1;r2 ′ =r2-δ1;r3 ′ =r3+δ2;r4 ′ =r4.

5. An axial piston pump according to claim 4, characterized in that, The first offset value is calculated according to the following formula: Among them, M vHx′ When the first offset value is greater than zero, the overturning moment generated by the oil film in the high-pressure zone of the distribution sub on the cylinder block unit; δ1 is the first offset value.

6. An axial piston pump according to claim 4, characterized in that, The second offset value is also related to the following formula: Among them, M vLx′ θ3 is the overturning moment generated by the oil film in the low-pressure zone of the distribution sub on the cylinder block unit; θ4 is the starting angle of the low-pressure zone of the distribution sub; p L The overturning force exerted on the cylinder unit by the oil film formed between the oil suction groove and the cylinder unit.

7. An axial piston pump according to claim 6, characterized in that, The axial piston pump also includes a valve unit, which includes a valve core body and a valve core spring; the valve unit is detachably connected to the distribution plate; the valve unit controls the opening and closing of the oil discharge port and the oil suction port with the piston cavity respectively; The calculation process for the first offset value and the second offset value is also related to the following formula: Among them, L s F is the axial length of the contact area between the cylinder block unit and the drive shaft; v F is the thrust of the valve core body; sp This is the preload force of the valve core spring.

8. An axial piston pump according to claim 7, characterized in that, The absolute value of the first offset value is less than the absolute value of the second offset value.

9. An axial piston pump according to claim 1, characterized in that, The depth of the oil drain groove is less than the depth of the oil drain port; the depth of the oil suction groove is less than the depth of the oil suction port; the depth directions of the oil drain groove, the oil drain port, the oil suction groove, and the oil suction port are perpendicular to the disc body.

10. An axial piston pump according to claim 1, characterized in that, The support layer and the disk body are integrally formed by 3D printing.

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