Piston pump with two degrees of freedom

Abstract

The present application provides a kind of double motion degree of freedom piston pump to solve the technical problems existing in existing piston pump.The piston pump includes: transmission shaft assembly;Pump core is arranged in pump shell structure and is rotatably arranged on transmission shaft assembly, and pump core adopts the integrated series connection structure of upper and lower two groups of pump core, and the series connection structure includes first and second piston structures, which are rotatably arranged on transmission shaft assembly along the axial direction of transmission shaft assembly, and the first and second piston structures both adopt the integrated structure of piston and cam guide rail, and the cam guide rail is located in the middle of piston, and two sleeve structures are symmetrically protruded on both sides of cam guide rail, and any sleeve structure includes outer and inner side cylinder, a plurality of oil suction ports are circumferentially formed on outer side cylinder, a plurality of oil discharge ports are circumferentially formed on inner side cylinder, and any oil suction port and any oil discharge port are staggered;Annular cavity is formed between outer side cylinder and inner side cylinder, the annular cavities of two sleeve structures are not communicated, and the inner side cylinders on both sides are communicated and form the inner cavity of piston structure.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of fluid machinery, and relates to a double-motion-freedom piston pump. BACKGROUND

[0002] A pump is an energy conversion device for converting mechanical energy and fluid pressure energy, and is usually used for outputting high-pressure fluid. In the working process of general piston pumps, vane pumps, gear pumps and screw pumps, the motion pairs of the mechanical structure are mainly in sliding friction, so that a large amount of friction energy is lost, and the shapes of the parts are complex and the processing cost is high.

[0003] The double-motion-freedom piston pump integrates the shaft and the piston, and realizes continuous oil suction and discharge by using the principle of double-freedom motion of the piston, i.e. circumferential rotation and axial reciprocation, so that the structure of the distribution disc of the traditional piston pump is omitted. Meanwhile, the symmetric cam guide roller structure is used to replace the sliding shoe swash plate structure, so that the sliding friction pair is changed into a rolling friction pair, and the symmetric force structure makes the piston not have a lateral force, so that two friction pairs, i.e. the piston and the cylinder and the cylinder and the distribution disc, are omitted, so that the pump efficiency is higher, and the restriction of the sliding friction pair on the pump performance is broken.

[0004] In the existing double-motion-degree-of-freedom piston pump structure, the following problems mainly exist: 1. The piston of the double-motion-degree-of-freedom piston pump is a single-side protruding structure, and the cam guide rail, roller and other parts are concentrated on the protruding side. With the increase of the power of the piston pump, the axial length of the piston pump is relatively large. 2. The piston is a groove type piston. When working, the piston drives the oil to rotate, causing oil stirring loss. Especially in the large flow state, the piston stirring power loss is large, and the energy conversion rate is not high. 3. The oil inlet flow channel is complex, the pressure loss along the way is large, and the self-priming capacity is not strong; 4. The piston is a groove type piston. At high speed, the circumferential rotation speed of the piston cavity is extremely large, and the oil cannot fill the piston cavity in time, causing air suction, and the pump has weak anti-cavitation capacity; 5. The piston is uniformly distributed with four flow distribution grooves on the cylindrical surface. When working, they are all single-side flow distribution (outward or inward), the interval between the flow distribution grooves is small, that is, the circumferential sealing length is short, and the leakage is large. For example, patent 202111544343.0 discloses a piston structure and a double-motion-degree-of-freedom piston pump. The structure connects the guide rail and the piston into a whole body by using a positioning pin. The roller and the guide rail are distributed on the protruding side of the piston, increasing the length of the pump in the axial direction. At the same time, the fluid in the piston cavity rotates with the rotation of the piston, increasing the oil stirring loss. The flow distribution grooves of the piston are uniformly distributed on the cylindrical surface. When working, they are single-side flow distribution, the interval between the flow distribution grooves is small, the sealing distance is short, and the leakage is large. Patent 202011354623.0 discloses a shaft flow distribution double-acting piston and a piston pump with the piston. A rotating reciprocating piston with a large middle and small heads is adopted to realize oil suction, discharge and distribution. When working, the piston drives the fluid in the piston cavity to rotate, causing increased oil stirring loss. At the same time, the rotating reciprocating functional assembly is complex, the structural inertia force increases under high speed and heavy load conditions, the mechanical efficiency decreases, and the flow distribution grooves also have the shortcomings of patent 202111544343.0, and the volumetric efficiency is not high. The two-dimensional piston pumps disclosed in the above patents have the problems of complex structure, low mechanical efficiency, large axial size and poor reliability of the pump structure.

[0005] In addition, in order to realize the double-degree-of-freedom motion of the piston "circumferential rotation + axial reciprocation", the transmission structure of the piston pump is very important. In the existing double-motion-degree-of-freedom piston pump transmission structure, the following problems mainly exist: 1. The volume and weight of the yoke roller transmission structure are large, and it occupies the axial space of the piston pump. With the increase of the power of the piston pump, the volume and weight of the piston pump increase, and the axial length of the pump changes greatly; 2. The weight of the yoke roller transmission structure is large, the moment of inertia of the pump core is large, the start-stop performance of the piston pump is poor, and the control performance of the piston pump is poor; 3. The yoke roller transmission structure drives the oil to rotate, causing oil stirring loss. Especially under high speed working conditions, the oil stirring loss of the transmission structure is huge; 4. The transmission structure of the through shaft plus the ball requires high coaxiality of the through shaft and the upper / lower pump core, increasing the process and assembly process and the processing time cost.

[0006] Patent 202010894767.9 discloses a shift fork roller torque transmission structure and a double-motion freedom piston pump with the structure. The structure utilizes a pair of shift forks and rollers linked together, and the shift forks and rollers are distributed on the outer extension side of the piston, increasing the length of the pump in the axial direction. At the same time, the shift fork roller torque transmission structure rotates with the rotation of the piston, increasing the oil stirring loss. The shift fork roller torque transmission structure has large volume and weight, increasing the rotational inertia of the pump core and reducing the start-stop performance and control performance of the pump. Patent 202111544343.0 discloses a piston structure and a double-motion freedom piston pump. In the pump, the transmission shaft has two groups of parallel linear ball grooves along the axial direction, and the linear ball grooves are arranged with balls. The input torque is transmitted through the transmission shaft, the linear ball groove, the ball and the piston. However, the torque transmission structure cannot well ensure the coaxiality of the transmission shaft and the upper / lower associated pump core. If the transmission shaft and the upper / lower associated pump core have insufficient coaxiality during machining and assembly, the pump is difficult to operate stably at high speed. The torque transmission structure disclosed in the above patents and the double-motion freedom piston pump containing the structure have problems of large volume and weight, large axial size, low mechanical efficiency and high machining precision requirement, which is not conducive to the stable operation of the pump at high speed. SUMMARY

[0007] The present application aims to at least solve one of the technical problems existing in the prior art.

[0008] To this end, the present application provides a double-motion freedom piston pump.

[0009] The technical solution of the present application is to provide a double-motion freedom piston pump, which comprises:

[0010] A front end cover, a pump shell and a rear end cover are sequentially fixed to form a pump shell structure;

[0011] A transmission shaft assembly;

[0012] A pump core is arranged in the pump shell structure and rotatably arranged on the transmission shaft assembly. The pump core adopts an upper / lower two-association pump core integrated series connection structure, which comprises a first piston structure and a second piston structure. The two structures are rotatably arranged along the axial direction of the transmission shaft assembly. The first piston structure and the second piston structure both adopt a piston and cam rail integrated structure, and the cam rail is located in the middle of the piston. Two sleeve structures are symmetrically arranged on both sides of the cam rail. For any sleeve structure, it comprises an outer sleeve and an inner sleeve located in the outer sleeve. A plurality of oil suction ports are arranged on the outer sleeve in the circumferential direction. A plurality of oil discharge ports are arranged on the inner sleeve in the circumferential direction. Any oil suction port and any oil discharge port are staggered. The annular cavities are formed between the outer sleeve and the inner sleeve, the annular cavities of the two sleeve structures are not connected, and the inner sleeves on both sides are connected and form the inner cavity of the piston structure.

[0013] Further, the series structure further comprises a first bushing, a second bushing and a pump core support frame, the first bushing, the first piston structure, the pump core support frame, the second piston structure, the second bushing are coaxially arranged along the transmission shaft assembly axis in sequence, the first bushing and the second bushing both comprise a baffle and a bushing sleeve arranged on the baffle, the bushing sleeve is composed of a bushing outer sleeve and a bushing inner sleeve located in the bushing outer sleeve, an annular cavity is formed between the bushing inner and outer sleeves, a plurality of oil distribution ports are uniformly distributed on the circumference of the bushing sleeve, any oil distribution port penetrates through the bushing outer sleeve and the bushing inner sleeve at the same time, the baffle has an inner hole penetrating through the baffle, the inner hole is in communication with the bushing inner sleeve to form the inner cavity of the bushing; the pump core support frame adopts an integrated cylinder structure, comprising a pump core support frame body, the pump core support frame body is fixedly connected with the pump shell, an oil discharge flow channel is formed in the pump core support frame body, the pump core support frame body has a first support arm bushing assembly and a second support arm bushing assembly respectively protruding from both ends of the pump core support frame body, the two assemblies are arranged at a preset angle, the first support arm bushing assembly is composed of a first support arm assembly and a first support sleeve, the second support arm bushing assembly is composed of a second support arm assembly and a second support sleeve, the first support sleeve and the second support sleeve have the same structure as the bushing sleeve, wherein the inner sleeve of the first support sleeve and the inner sleeve of the second support sleeve are in communication with the oil discharge flow channel to form the inner cavity of the pump core support frame.

[0014] Wherein, the first bushing, the first piston structure and the first support arm bushing assembly cooperate, the second bushing, the second piston structure and the second support arm bushing assembly cooperate, the piston structure is arranged between the corresponding bushing and the support arm bushing assembly, the inner cavities of the first bushing, the first piston structure, the pump core support frame and the second bushing are in sequence in communication; the support arm assembly is fixedly connected with the baffle of the corresponding bushing, the bushing sleeve is embedded in the annular cavity of the corresponding cam guide rail side sleeve to form a closed oil chamber, the corresponding support sleeve is embedded in the annular cavity of the cam guide rail other side sleeve to form another closed oil chamber, the four closed oil chambers of the series structure work regularly to suck and discharge oil.

[0015] Further, the series structure further comprises a first end cover and a second end cover, the first end cover is fixedly connected with the baffle of the first bushing, the first end cover has an inner hole penetrating through the first end cover and is in communication with the inner hole on the baffle, the first end cover and the bushing sleeve on the baffle are respectively arranged on both sides of the baffle, the second end cover is fixedly connected with the baffle of the second bushing and the bushing sleeve on the baffle is respectively arranged on both sides of the baffle.

[0016] Further, the piston pump further comprises a first thrust bearing and a second thrust bearing, which are arranged at the first end cover and the second end cover respectively, one end of the transmission shaft assembly is matched with the first thrust bearing and arranged in the inner hole of the first end cover, and the other end of the transmission shaft assembly is matched with the second thrust bearing.

[0017] Further, for any sleeve structure, a pair of oil suction ports are symmetrically arranged on the outer sleeve, a pair of oil discharge ports are symmetrically arranged on the inner sleeve, and the pair of oil suction ports and the pair of oil discharge ports are arranged orthogonally; for any bush sleeve, a pair of symmetrically arranged oil distribution ports are arranged on the bush sleeve along the circumferential direction, and any oil distribution port is composed of an oil distribution port on the bush outer sleeve and an oil distribution port on the bush inner sleeve, and the oil distribution ports on the bush outer sleeve and the bush inner sleeve are arranged parallel to each other.

[0018] Further, any oil distribution port further extends to the free end of the corresponding sleeve.

[0019] Further, the end face of the oil suction port is designed as a bevel, wherein the outer opening area of the oil suction port is larger than the inner opening area; and / or the end face of the oil discharge port is designed as a bevel, wherein the outer opening area of the oil discharge port is larger than the inner opening area.

[0020] Further, the cross-sectional area of the oil suction port is larger than that of the oil discharge port.

[0021] Further, a plurality of shift forks are symmetrically arranged on the inner cavity of the piston structure along the radial direction, and linear ball grooves are arranged on the shift forks for ball torque transmission.

[0022] Further, high-pressure flow channels are processed on the inner cavity wall except the shift forks, and the high-pressure flow channels are communicated with the oil discharge ports and the oil discharge flow channels.

[0023] Further, the pump core support frame body is in the shape of a circular truncated cone, an annular groove is arranged on the circumferential side wall of the circular truncated cone, a body oil discharge port is arranged on the annular groove, and the annular groove is communicated with the oil discharge flow channel in the body, and the annular groove and the pump shell form a high-pressure cavity.

[0024] Further, a plurality of oil passage grooves are arranged on the pump core support frame body along the circumferential direction, any oil passage groove is arranged along the axial direction of the pump core support frame body and is not communicated with the oil discharge flow channel, and the oil passage groove is used to realize oil circulation in the entire pump shell.

[0025] Further, the first support arm assembly and the second support arm assembly each consist of two symmetrically arranged support arms; the cam guide rail is a double-sided cam guide rail; the double-sided flow distribution structure further comprises a first roller frame assembly and a second roller frame assembly, the first roller frame assembly cooperates with the first support arm assembly and the first piston structure, the second roller frame assembly cooperates with the second support arm assembly and the second piston structure, the first roller frame assembly and the second roller frame assembly each comprise two groups of roller assemblies, the two groups of roller assemblies are arranged in the length direction of the corresponding support arm assembly, any roller assembly comprises a roller frame and a plurality of rollers, the roller frame is fixedly connected with the corresponding two support arms, the plurality of rollers are arranged on the inner wall of the roller frame in the circumferential direction of the roller frame, and the double-sided cam guide rail is clamped between the plurality of rollers of the two groups of roller assemblies; wherein, when the piston structure rotates, the rollers of the two groups of roller assemblies can move along the circumferences of the two sides of the double-sided cam guide rail, respectively.

[0026] Further, the transmission shaft assembly comprises an input transmission shaft, a first transmission block, a first transmission shaft, a second transmission block and a second transmission shaft which are sequentially connected; the two end faces of the first transmission block are provided with sliding grooves a and b which are orthogonally distributed; the two end faces of the second transmission block are provided with sliding grooves c and d which are orthogonally distributed; one end of the input transmission shaft is a power input end which cooperates with the first thrust bearing, and the other end is a flat square structure c which cooperates with the sliding groove a; the first transmission shaft is arranged in the inner cavity of the first piston structure, and a plurality of straight linear ball grooves which are parallel to the axis are uniformly distributed in the circumferential direction of the first transmission shaft for placing balls and cooperating with the straight linear ball grooves of the first piston structure; the two ends of the first transmission shaft are further respectively provided with a flat square structure a and a flat square structure b which cooperate with the sliding groove b and the sliding groove c, respectively; the second transmission shaft is arranged in the inner cavity of the second piston structure, and a plurality of straight linear ball grooves which are parallel to the axis are uniformly distributed in the circumferential direction of the second transmission shaft for placing balls and cooperating with the straight linear ball grooves of the second piston structure; one end of the second transmission shaft is further provided with a flat square structure d which cooperates with the sliding groove d; the other end of the second transmission shaft cooperates with the second thrust bearing;

[0027] Wherein, any sliding groove has a plurality of inner wall surfaces, part of the plurality of inner wall surfaces are provided as transmission surfaces, and the rest are provided as non-transmission surfaces, the transmission surfaces of the sliding grooves on the two end faces of the same transmission block are perpendicular to each other, the flat square structure a, the flat square structure b, the flat square structure c and the flat square structure d each have a transmission surface and a non-transmission surface which cooperate with the corresponding sliding groove, the transmission surface of any flat square structure is closely attached to the transmission surface of the corresponding sliding groove, and the non-transmission surface of any flat square structure has a gap with the non-transmission surface of the corresponding sliding groove, during work, the input transmission shaft and the first transmission shaft can slide along the normal direction of the non-transmission surface while transmitting torque through the transmission surface, and the first transmission shaft and the second transmission shaft can also slide along the normal direction of the non-transmission surface while transmitting torque through the transmission surface.

[0028] Further, any of the sliding grooves is a rectangular groove, one of two inner walls of the rectangular groove arranged in parallel with each other is arranged as a transmission surface, and the other two surfaces are non-transmission surfaces.

[0029] Further, the length of the transmission surface is greater than the length of the non-transmission surface.

[0030] Further, any of the straight-line ball grooves is not filled with balls, and the length of the straight-line ball groove without balls is ΔL, ΔL = h / π, where h is the guide rail stroke of the piston pump.

[0031] Further, the length of any straight-line ball groove is L:

[0032] L = nD + h / π

[0033] Wherein, L is the length of the straight-line ball groove, D is the ball diameter, n is the number of balls, and h is the guide rail stroke.

[0034] Further, the transmission shaft assembly comprises:

[0035] Two transmission blocks are arranged one-to-one corresponding to the first piston structure and the second piston structure, the transmission block is a hollow column structure with two open ends, a pair of inner transmission grooves are uniformly arranged on the inner cavity wall of the transmission block in the circumferential direction, a pair of outer transmission grooves are uniformly arranged on the outer wall of the transmission block in the circumferential direction, any inner transmission groove and outer transmission groove are arranged along the length direction of the transmission block, the pair of inner transmission grooves and the pair of outer transmission grooves are arranged orthogonally, any transmission block is arranged in the inner cavity of the corresponding piston structure, and the transmission groove on the outer side of the transmission block is matched with the balls in the ball groove of the corresponding piston structure.

[0036] A transmission through shaft is arranged in the two transmission blocks, and the two transmission blocks are arranged in the axial direction of the transmission through shaft; the inner transmission groove of any transmission block is matched with the shift fork of the transmission through shaft, and the two ends of the transmission through shaft are matched with the first thrust bearing and the second thrust bearing, respectively.

[0037] A plurality of limiting parts are arranged at the two ends of any transmission block, the limiting part is further fixedly sleeved on the transmission through shaft, and the limiting part is used to limit the movement of the two transmission blocks in the axial direction of the transmission through shaft.

[0038] Wherein, during operation, the transmission through shaft drives the two transmission blocks to rotate, the two transmission blocks distribute the torque to the first piston structure and the second piston structure through the balls, so that the first piston structure and the second piston structure rotate in the circumferential direction.

[0039] Further, the two transmission blocks, the first piston structure, the second piston structure and the transmission through shaft are coaxial; and / or the two-end open hollow cylindrical structure is a two-end open hollow cylindrical structure.

[0040] Compared with the prior art, the present application has the following beneficial effects:

[0041] (1) The piston sleeve and the double-sided guide rail are integrated, the rollers can be distributed on the outer side of the piston sleeve, the axial distance of the piston can be fully utilized, the axial length of the pump is effectively shortened, the volume and weight of the pump are reduced, and the power-weight ratio of the pump is improved.

[0042] (2) The piston and the liner are both baffle structures, the liner replaces the traditional cylinder part, and the piston and the liner are hollowed in the middle and are circumferentially slotted, so that the weight of the pump is greatly reduced.

[0043] (3) The piston and the liner are both baffle structures, the resistance of the integrated guide rail piston during rotation and reciprocating motion is reduced, the power loss of oil stirring is reduced, and the mechanical efficiency of the pump is improved.

[0044] (4) The piston is double-sided flow distribution, the oil suction port and the oil discharge port are distributed on different cylinders, the distance between the oil ports is indirectly increased, the sealing length is increased, the leakage is effectively reduced, and the volumetric efficiency of the pump is improved.

[0045] (5) The piston cavity oil suction port is arranged on the guide rail piston sleeve and directly communicates with the oil, the oil can enter the piston cavity without passing through any flow channel, and the self-suction capacity of the pump is effectively increased.

[0046] (6) The piston is a baffle structure, the oil entering the piston cavity almost does not have circumferential rotation, the axial speed of the oil is small due to the small piston stroke, the kinetic energy loss of the oil is extremely small, and the energy conversion rate of the pump is high.

[0047] (7) The piston is a baffle structure, at high speed, the oil can quickly follow the axial movement of the piston and timely fill the piston cavity, and the anti-cavitation ability of the pump is greatly enhanced.

[0048] (8) By adopting the structure, when the piston cavity is in the oil compression stroke, the liner is slightly deformed under the action of high-pressure oil, the gap between the liner and the piston is reduced, the leakage is reduced, and the volumetric efficiency is improved. This gap compensation structure is also applicable at high temperature.

[0049] (9) compared with the shifter roller torque transmission structure, the orthogonal / cross torque transmission structure is small in size, the torque transmission structure is arranged in the piston, and the axial length of the pump is not affected; and the orthogonal / cross torque transmission structure is light in weight, short in rotation radius, small in moment of inertia, good in start-stop performance, and good in control performance of the pump; compared with the external shifter roller torque transmission structure, the orthogonal / cross torque transmission structure is distributed in the piston, and oil stirring loss is extremely small, and is suitable for high-speed working conditions; the orthogonal / cross torque transmission structure realizes decoupling of upper and lower pump cores in rotary motion, reduces coaxiality requirements of the upper and lower pump cores, reduces machining precision requirements, reduces machining cost, and improves economic benefits. BRIEF DESCRIPTION OF DRAWINGS

[0050] The accompanying drawings, which are included to provide a further understanding of the embodiments of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those of ordinary skill in the art without creative labor on the basis of these drawings.

[0051] Figure 1 It is a structural schematic diagram of the double-motion-freedom piston pump of the application;

[0052] Figure 2 It is a structural schematic diagram (perspective view) of the pump core assembly of the application;

[0053] Figure 3 It is a structural schematic diagram (exploded view) of the pump core assembly of the application;

[0054] Figure 4 It is a structural schematic diagram of the integrated baffle type guide rail piston of the application;

[0055] Figure 5 It is a sectional view of Figure 4 ;

[0056] Figure 6 It is a top view of Figure 4 ;

[0057] Figure 7 It is a schematic diagram of the wave peak and wave trough positions of the guide rail piston guide rail profile;

[0058] Figure 8 It is a schematic diagram of the flow distribution principle of the application;

[0059] Figure 9 It is a structural diagram of the pump core support frame;

[0060] Figure 10 It is a schematic diagram of the roller frame;

[0061] Figure 11The schematic diagram of the integrated guide rail piston structure with balanced support of the present application;

[0062] Figure 12 The schematic diagram of the cross transmission structure of the present application (front view and sectional view) ;

[0063] Figure 13 The isometric view of Figure 12 ;

[0064] Figure 14 The schematic diagram of the transmission block transmission surface of the present application;

[0065] Figure 15 The schematic diagram of the orthogonal transmission structure of the present application (front view and sectional view) ;

[0066] Figure 16 The isometric view of Figure 15 (hiding the second piston structure) ;

[0067] Figure 17 The schematic diagram of the orthogonal transmission structure of the present application (top view) ;

[0068] Figure 18 The schematic diagram of the transmission through shaft structure of the present application (perspective view) ;

[0069] Figure 19 The schematic diagram of the transmission block structure of the present application (perspective view). DETAILED DESCRIPTION

[0070] It should be noted that the embodiments and the features in the embodiments in the present application can be combined with each other without conflicts. The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. The description of the at least one exemplary embodiment is actually only illustrative, but not intended to limit the present application and its application or use in any way. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of the present application.

[0071] It should be noted that the terms used herein are only for describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present application. As used herein, the singular form is intended to include the plural form, unless the context clearly indicates otherwise, and it should also be understood that, when the terms "comprise" and / or "include" are used in the specification, there is a presence of the features, steps, operations, devices, components and / or combinations thereof.

[0072] The relative arrangement of parts and steps, numerical expressions, and numerical values set forth in the examples herein are not intended to limit the scope of the application unless specifically so stated. Also, it is to be understood that the dimensions shown in the drawings are not necessarily to scale. Techniques, methods, and devices known to those of ordinary skill in the relevant art can not be discussed in detail, but should be considered as part of the description of the application. In all examples shown and discussed herein, any specific value should be interpreted as merely an example, and not a limitation. Thus, other examples of the exemplary embodiments can have different values. It is noted that like numbers and letters refer to like items throughout the drawings, and once an item is defined in one drawing, it need not be discussed further in subsequent drawings.

[0073] As Figures 1-19 shown in one embodiment of the present application, a double motion freedom piston pump is provided, which comprises a front end cover 1, a pump shell 6, a rear end cover 9, a pump core and a transmission shaft assembly, wherein the front end cover 1, the pump shell 6 and the rear end cover 9 are sequentially fixed to form a pump shell structure, the pump core is arranged in the pump shell structure, the pump core adopts an integrated series structure of upper and lower two pump cores, the series structure comprises a first piston structure 4 and a second piston structure 18, both of which are rotatably arranged on the transmission shaft assembly along the axis direction of the transmission shaft assembly, the first piston structure 4 and the second piston structure 18 both adopt an integrated structure of a piston and a cam guide rail, the cam guide rail is located in the middle of the piston, and two sleeve structures symmetrically protrude on both sides of the cam guide rail, for any sleeve structure, it comprises an outer sleeve and an inner sleeve located in the outer sleeve, a plurality of oil suction ports are circumferentially formed on the outer sleeve, a plurality of oil discharge ports are circumferentially formed on the inner sleeve, and any oil suction port and any oil discharge port are staggered; the annular cavities are formed between the outer sleeve and the inner sleeve, the annular cavities of the two sleeve structures are not communicated, and the inner sleeves on both sides are communicated and form the inner cavity of the piston structure.

[0074] That is, as Figure 5 shown, the annular cavities of the two sleeve structures are not communicated, which means that the two annular cavities are separated by an annular baffle 48.

[0075] Specifically, as Figures 3-8 shown, the first piston structure 4 comprises a first cam guide rail 43 and sleeve structures on both sides thereof, both of which comprise a first outer sleeve 41 and a first inner sleeve 42, and the first outer sleeve 41 and the first inner sleeve 42 are respectively provided with oil suction ports and oil discharge ports. Similarly, the second piston structure 18 comprises a second cam guide rail 181 and sleeve structures on both sides thereof, both of which comprise a second outer sleeve 182 and a second inner sleeve 183, and the second outer sleeve 182 and the second inner sleeve 183 are respectively provided with oil suction ports and oil discharge ports.

[0076] In the embodiment of the present application, the outer cylinder and the inner cylinder of the piston structure are both open structures, the inner cylinders at both ends are connected, and the end faces of the outer cylinder and the inner cylinder of the sleeve are preferably flush.

[0077] Preferably, the outer cylinder and the inner cylinder of the piston structure are both cylindrical.

[0078] In addition, those skilled in the art should understand that the rotating shaft assembly in the embodiment of the present application is similar to the transmission through shaft of the existing piston pump, which is arranged in the pump core and drives the piston structure to rotate, and the piston structure moves axially and reciprocally under the guidance of the cam guide rail.

[0079] It can be seen that the first piston structure and the second piston structure (sleeve structure) in the embodiment of the present application are both baffle structures, hollowed in the middle and slotted in the circumference, which greatly reduces the weight of the pump and improves the power-weight ratio of the pump. At the same time, the agitation of the oil is small when rotating, the oil agitation loss is reduced, the mechanical efficiency is high, and when the pump is at high speed, the oil can quickly follow the axial movement of the piston and timely fill the piston cavity, greatly enhancing the anti-cavitation ability of the pump. The piston is double-sided flow distribution, the oil suction port and the oil discharge port are distributed on different cylinders, indirectly increasing the distance between the oil ports, increasing the sealing length, effectively reducing the leakage, and improving the volumetric efficiency of the pump. In the embodiment of the present application, the oil suction port of the piston cavity is arranged on the outer sleeve of the piston structure, and by using the piston structure, the oil suction port can be directly communicated with the oil, and the oil can enter the piston cavity without passing through any flow channel, effectively increasing the self-suction capacity of the pump. In addition, the cam guide rails in the embodiment of the present application are all in the middle of the piston, compared with the previous structure in which the guide rails and the roller are concentratedly distributed on one side, the rollers can be distributed on the outer side of the piston sleeve, the axial distance of the piston can be fully utilized, the axial length of the pump can be effectively shortened, and the volume of the pump can be reduced.

[0080] In the above embodiment, as Figures 2-3As shown, in order to realize bidirectional flow distribution, the series structure further comprises a first bushing 13, a second bushing 20 and a pump core support frame 16, the first bushing 13, the first piston structure 4, the pump core support frame 16, the second piston structure 18 and the second bushing 20 are coaxially arranged along the transmission shaft assembly axis in sequence, the first bushing 13 and the second bushing 20 each comprise a baffle and a bushing sleeve arranged on the baffle, the bushing sleeve is composed of a bushing outer sleeve and a bushing inner sleeve located in the bushing outer sleeve, an annular cavity is formed between the bushing inner and outer sleeves, a plurality of oil distribution ports are uniformly distributed in the circumferential direction of the bushing sleeve, any oil distribution port penetrates the bushing outer sleeve and the bushing inner sleeve at the same time, the baffle has an inner hole penetrating the baffle, the inner hole is in communication with the bushing inner sleeve to form the inner cavity of the bushing; the pump core support frame 16 adopts an integrated cylinder body structure, comprising a pump core support frame body 161, the pump core support frame body 161 is fixedly connected with the pump housing 6, an oil discharge flow channel is formed in the inside of the pump core support frame body 161, the pump core support frame body 161 has a first support arm bushing assembly and a second support arm bushing assembly respectively protruding from both ends, the two assemblies are arranged at a preset angle, the first support arm bushing assembly is composed of a first support arm assembly and a first support sleeve, the second support arm bushing assembly is composed of a second support arm assembly and a second support sleeve, the first support sleeve and the second support sleeve have the same structure as the bushing sleeve, wherein the inner sleeve of the first support sleeve and the inner sleeve of the second support sleeve are in communication with the oil discharge flow channel to form the inner cavity of the pump core support frame 16; wherein the first bushing 13, the first piston structure 4 and the first support arm bushing assembly cooperate, the second bushing 20, the second piston structure 18 and the second support arm bushing assembly cooperate, the piston structure is arranged between the corresponding bushing and the support arm bushing assembly, the inner cavities of the first bushing 13, the first piston structure 4, the pump core support frame 16 and the second bushing 20 are in sequence in communication; the support arm assembly is fixedly connected with the baffle of the corresponding bushing, the bushing sleeve is embedded in the annular cavity of the corresponding cam guide rail side sleeve to form a closed oil cavity, the corresponding support sleeve is embedded in the annular cavity of the cam guide rail other side sleeve to form another closed oil cavity, the four closed oil cavities of the series structure work regularly to suck and discharge oil.

[0081] That is, the first bushing 13, the first piston structure 4, the pump core support frame 16, the second piston structure 18 and the second bushing 20 are coaxially arranged along the axis in sequence, the first piston structure 4 is arranged between the first bushing 13 and the first support arm bushing assembly, the first bushing 13 is fixedly connected with the first support arm assembly, the bushing sleeve of the first bushing 13 is embedded in the annular cavity of the cam guide rail one side sleeve of the first piston structure 4, and the first support sleeve is embedded in the annular cavity of the other side sleeve, thereby forming two closed oil cavities. Similarly, the second piston structure 18, the second bushing 20 and the second support arm bushing assembly also adopt the same cooperation mode, thereby forming the four closed oil cavities of the series structure.

[0082] Preferably, the first support arm bushing assembly and the second support arm bushing assembly are arranged at an angle of 45 degrees, that is, the first support arm assembly is arranged at an angle of 45 degrees with the second support arm assembly, and the first support sleeve is arranged at an angle of 45 degrees with the second support sleeve, so that the pump output flow is not pulsated.

[0083] Preferably, the bushing sleeve and the support sleeve are both cylindrical sleeves.

[0084] Preferably, for any sleeve structure, a pair of oil suction ports are symmetrically arranged on the outer cylinder, and a pair of oil discharge ports are symmetrically arranged on the inner cylinder, and the oil suction ports and the oil discharge ports are arranged orthogonally; for any bushing sleeve, a pair of symmetrically arranged oil distribution ports are arranged on the bushing sleeve along the circumferential direction, and any oil distribution port is formed by an oil distribution port on the bushing outer cylinder and an oil distribution port on the bushing inner cylinder, and the oil distribution ports on the bushing outer cylinder and the bushing inner cylinder are arranged parallel to each other.

[0085] Specifically, the piston structure of the embodiment of the present application integrates the functions of oil suction and discharge, oil distribution and transmission. Figures 3-8 As shown in the figure, the first piston structure 4 includes a first cam guide rail 43 and sleeve structures on both sides thereof, both including a first outer cylinder 41 and a first inner cylinder 42, and a pair of oil suction ports 44 and oil discharge ports 45 are arranged orthogonally on the first outer cylinder 41 and the first inner cylinder 42, respectively. Similarly, the second piston structure 18 includes a second cam guide rail 181 and sleeve structures on both sides thereof, both including a second outer cylinder 182 and a second inner cylinder 183, and a pair of oil suction ports and oil discharge ports are arranged orthogonally on the second outer cylinder 182 and the second inner cylinder 183, respectively.

[0086] In addition, the first support sleeve and the second support sleeve of the embodiment of the present application are the same as the bushing sleeve structure, and will not be described in detail here.

[0087] In the above embodiment, in order to achieve better oil suction and discharge, as shown in the figure, Figure 3 , Figure 9 As shown in the figure, any oil distribution port also extends to the free end of the corresponding sleeve.

[0088] That is, the series structure of the embodiment of the present application is a double-sided flow distribution structure, and a new baffle piston structure (first piston structure and second piston structure) is proposed. The baffle piston is an integrated structure of a cam guide rail and a piston, the cam guide rail is in the middle of the piston, and the cam guide rail symmetrically extends outwards on both sides of the piston to form inner and outer cylindrical sleeves. Meanwhile, the structure also designs the traditional liner structure matched with the piston structure as a baffle liner structure (first liner, second liner, and first support sleeve and second support sleeve in the embodiment of the present application). The baffle liner is embedded in the baffle piston to form a closed volume. With the increase and decrease of the closed volume, the piston pump can complete the expansion and compression of the fluid. Among them, a pair of oil distribution ports are respectively arranged on the inner and outer sleeves of the piston structure, and the two pairs of oil distribution ports are in an orthogonal position. The oil distribution port on the outer sleeve is an oil suction port, and the oil distribution port on the inner sleeve is an oil discharge port. The baffle liner extends outwards on both sides to form inner and outer sleeves, and two pairs of central symmetric oil grooves (oil distribution ports) are parallelly arranged on the baffle liner. During the operation of the piston pump, the transmission shaft assembly drives the piston structure to rotate through the transmission of the ball. The piston structure can complete the axial reciprocating motion under the guidance of the cam guide rail surface. When the oil suction port communicates with the outer baffle oil groove, the piston is in the oil suction stroke, and the oil enters the piston cavity from the pump cavity through the oil suction port; when the oil discharge port communicates with the inner baffle oil groove, the piston is in the oil discharge stroke, and the fluid flows out of the piston cavity through the oil discharge port.

[0089] It can be seen that the piston and the double-sided guide rail are integrated in the embodiment of the present application to form an integrated guide rail piston. The cam guide rail is in the middle of the piston. Compared with the structure in which the guide rail and the roller are concentrated on one side, the roller can be distributed on the outer side of the piston sleeve, the axial distance of the piston can be fully utilized, the axial length of the pump can be effectively shortened, and the volume of the pump can be reduced. Moreover, the piston of the embodiment of the present application is double-sided flow distribution, the oil suction port and the oil discharge port are distributed on different cylinders, the distance between the oil ports is indirectly increased, the sealing length is increased, the leakage amount is effectively reduced, and the volumetric efficiency of the pump is improved. With this piston structure, the oil can directly enter the piston cavity without passing through a complex flow channel, the self-priming capacity of the pump is increased; the oil entering the piston cavity almost does not have a circumferential rotational motion, at the same time, the axial speed of the oil is small because the piston stroke is small, the kinetic energy loss of the oil is extremely small, and the energy conversion rate of the pump is high; at high speed, the oil can quickly follow the axial motion of the piston and timely fill the piston cavity, and the anti-cavitation capacity of the pump is greatly enhanced.

[0090] In the above embodiment, in order to realize rotation, a plurality of yokes are symmetrically extended outwards on the inner cavities of the first piston structure 4 and the second piston structure 18 in the radial direction, and a linear ball groove is arranged on the yoke for ball transmission.

[0091] Among them, one linear ball groove is arranged on any yoke for the cross transmission, and two linear ball grooves are arranged side by side on any yoke for the orthogonal transmission.

[0092] Preferably, the fork is preferably 2, two forks are symmetrically arranged.

[0093] In the above embodiment, in order to better realize oil discharge, a high-pressure flow channel 49 is machined on the wall of the inner cavity except the fork, and the high-pressure flow channel communicates with the oil discharge port and the oil discharge flow channel.

[0094] Specifically, since the first piston structure 4 and the second piston structure 18 are consistent in structure, taking the first piston structure 4 as an example, as shown in the figure, a through hole is machined in the center of the first piston structure 4, a high-pressure flow channel 49 is machined on the wall surface of the through hole, and a first torque transmission fork 46 is machined at a right angle position of the high-pressure flow channel 49. Figures 4-8

[0095] In the above embodiment, the end face of the oil suction port is designed with an inclined surface, wherein the outer opening area of the oil suction port is larger than the inner opening area; and the end face of the oil discharge port is designed with an inclined surface, wherein the outer opening area of the oil discharge port is larger than the inner opening area. That is, the end faces of the oil suction port and the oil discharge port are designed with inclined surfaces, which can effectively increase the self-suction capacity and reduce the hydraulic loss caused by the outer diameter end face during the rotation of the piston. Under high pressure conditions, the bushing is slightly deformed under the action of high-pressure oil, which reduces the gap between the bushing and the piston, reduces the leakage, and improves the volumetric efficiency.

[0096] In the above embodiment, the cross-sectional area of the oil suction port is larger than the cross-sectional area of the oil discharge port.

[0097] In the embodiment of the application, since the cross-sectional area of the oil suction port is larger than that of the oil discharge port, and the inner diameter of the outer cylinder is larger than that of the inner cylinder, the cross-sectional area of the oil suction port is larger than that of the oil discharge port. The oil in the pump housing can directly enter the piston cavity through the oil suction port of the outer cylinder without passing through a complex flow channel, which is more conducive to oil suction of the pump. At the same time, due to the adoption of the baffle type piston structure and the bushing structure, the oil entering the piston cavity does not produce rotational motion, and the oil can quickly follow the axial motion of the guide rail piston and timely fill the piston cavity, thereby reducing the oil stirring loss and enhancing the anti-cavitation ability of the pump.

[0098] Specifically, the application adopts an integrated series connection structure of upper and lower pump cores, as shown in the figure. Figure 2 , Figure 3 ​As shown, it comprises a first bushing 13, a first piston structure 4, an integrated pump core support frame 16, a second piston structure 18, and a second bushing 20. The bushing sleeve (consisting of a first bushing outer sleeve 131 and a first bushing inner sleeve 132) of the first bushing 13, the first piston structure 4, and the first support sleeve (consisting of a first support outer sleeve 1610 and a first support inner sleeve 1611) are nested and assembled to form two closed oil cavities; at the same time, the bushing sleeve (consisting of a second bushing outer sleeve 201 and a second bushing inner sleeve 202) of the second bushing 20, the second piston structure 18, and the second support sleeve (consisting of a second support outer sleeve 167 and a second support inner sleeve 168) are nested and assembled to form another two closed oil cavities, and the four closed oil cavities work regularly to suck and discharge oil. In order to realize non-pulsation of pump output flow, the upper and lower two pump cores are arranged at a difference of 45°. The two bushings are fastened and connected with the pump core support frame 16 through nuts, which are used to support and lubricate the first piston structure 4 and the second piston structure 18. Since the piston structure and the bushing are both baffle type structures, the bushing replaces the traditional cylinder part, and the hollow part between the two is circumferentially slotted, which greatly reduces the weight of the pump. At the same time, when the oil enters the closed oil cavity, it is not affected by the rotational movement of the guide rail piston, and the oil does not produce rotational movement, the power loss of stirring oil is reduced, and the mechanical efficiency of the pump is improved.

[0099] Since the first piston structure 4 and the second piston structure 18 have the same principle of oil suction and discharge, flow distribution, and transmission, the following will take the first piston structure 4 as an example to introduce the principle of oil suction and discharge, flow distribution, and transmission. When the transmission shaft assembly drives the first piston structure 4 to rotate, the first piston structure 4 moves axially under the guidance of the guide rail surface, and a closed oil cavity can be formed by the first piston structure 4 and the first bushing 13. In the process of the first piston structure 4 moving from the highest point to the lowest point, the first piston structure 4 is in the oil discharge stroke, the piston cavity volume becomes smaller, the oil is compressed, and the oil in the piston cavity flows into the high-pressure flow channel 49 through the inner oil passage groove on the first bushing 13 and the oil discharge port 45 of the first piston structure 4, completing the oil discharge; in the process of the first piston structure 4 moving from the lowest point to the highest point, the first piston structure 4 is in the oil suction stroke, the piston cavity volume becomes larger, a vacuum is formed, and the oil in the shell can be sucked into the piston cavity through the oil suction port 44 of the first piston structure 4 and the outer oil passage groove on the first bushing 13 without complex flow channel, completing the oil suction, and the oil suction and discharge of the left and right piston cavities of the first piston structure 4 are alternately performed.

[0100] In the above embodiment, as shown in Figure 9 In order to better realize oil discharge, the pump core support frame body 161 is in the shape of a circular truncated cone, the circular truncated cone circumferential side wall is provided with an annular groove 166, the annular groove 166 is provided with a body oil discharge port 1612, and communicates with the oil discharge flow channel in the body, and the annular groove 166 and the pump shell 6 form a high-pressure cavity.

[0101] In the above embodiment, as shown in Figure 9 In order to realize the oil flow between the upper pump core and the second pump core, a plurality of oil flow grooves 169 are formed on the pump core support frame body 161 in the circumferential direction, and any of the oil flow grooves 169 is arranged in the axial direction of the pump core support frame body 161 and is not communicated with the oil discharge flow channel, and the oil flow grooves 169 are used to realize the oil flow in the entire pump shell structure.

[0102] That is, when the pump core support frame 16 of the present application is matched with the pump shell 6, the annular groove 166 on the pump core support frame body 161 is circumferentially sealed with the pump shell 6 (as shown in Figure 9 The pump core support frame body 161 is provided with two annular sealing grooves 163 which are distributed on both sides of the annular groove 166, and a sealing ring can be placed in the sealing groove to realize the sealing with the pump shell 6), and a high-pressure cavity is formed, so that the pump shell structure is divided into two chambers, and in order to realize the oil flow in the entire pump, the oil discharge flow channel of the body can be avoided, and a plurality of oil flow grooves 169 are arranged on the body to realize the flow in the pump shell structure.

[0103] According to an embodiment of the present application, as shown in Figure 3 , 9 The first support arm assembly and the second support arm assembly are both composed of two symmetrically arranged support arms 164. The two support arms are arranged at a difference of 45°, and two mounting holes 162 are formed on the support arm 164 for mounting the roller frame 8.

[0104] In addition, the pump core support frame body 161 is provided with pump core support frame 16 lugs 165 on the end face, preferably two, which are used for the axial and angular positioning of the pump core and are mounted in the lug grooves of the pump shell 6.

[0105] The through hole in the middle of the integrated cylinder structure is formed by one-time machining, which ensures the coaxiality of the upper and lower pump cores, solves the piston eccentric wear and adhesion problem caused by the misalignment of the upper and lower pump cores, and improves the working reliability of the pump.

[0106] According to an embodiment of the present application, as shown in Figure 2 , Figure 10 , Figure 11As shown, the cam guide rail is a double-sided cam guide rail, the series structure further comprises a first roller frame assembly and a second roller frame assembly, the first roller frame assembly is matched with the first support arm assembly and the first piston structure 4, the second roller frame assembly is matched with the second support arm assembly and the second piston structure 18, the first roller frame assembly and the second roller frame assembly both comprise two groups of roller assemblies, the two groups of roller assemblies are arranged along the length direction of the corresponding support arm assembly, any roller assembly comprises a roller frame and a plurality of rollers, the roller frame is fixedly connected with the corresponding two support arms, the plurality of rollers are arranged on the inner wall of the roller frame in a circumferential direction, and the double-sided cam guide rail is clamped between the plurality of rollers of the two groups of roller assemblies.

[0107] In the embodiment of the application, the cam guide rail curve has wave crests and wave troughs, and preferably, there are two wave crests and two wave troughs.

[0108] In the embodiment of the application, preferably, the roller frame is connected with the corresponding two support arms through a pin and can rotate around the pin. At all times, the two rollers on one side are in contact with the cam guide rail, and the axial force borne by the piston structure is evenly shared.

[0109] Specifically, the four roller assembly structures are consistent, namely, the first, second, third and fourth roller assemblies, which all comprise rollers and roller frames. The following takes the first roller assembly as an example to describe the structures of the first, second, third and fourth roller assemblies.

[0110] As shown in Figure 10 , 11 The first roller assembly comprises a first roller frame 8 and a first roller 5, preferably two first rollers 5, and further preferably, the rollers are bolt-type roller needle bearings, which are evenly distributed and fixed on the positioning holes 81 of the roller frame 8 by bolts. The first roller assembly is fixedly installed on the mounting hole 162 of the support arm 164 of the pump core support frame 16 through the pin a19 (the corresponding first roller frame 8 has a pin hole 83 matched with the support arm 164), and the roller 5 is tightly attached to the first cam guide rail 43 through a zero-clearance assembly method. The roller assembly can rotate around the pin a19, at all times, the two rollers on one side are in contact with the cam guide rail, and the axial force borne by the guide rail piston is evenly shared.

[0111] Further, as shown in Figure 3As shown, the series structure further comprises a first end cover 12 and a second end cover 10, the first end cover 12 is fixedly connected with the baffle of the first bushing 13, the first end cover 12 has an inner hole penetrating through the first end cover 12 and is communicated with the inner hole on the baffle, the first end cover 12 and the bushing sleeve on the baffle are respectively arranged on two sides of the baffle, and the second end cover 10 is fixedly connected with the baffle of the second bushing 20 and is respectively arranged with the bushing sleeve on the baffle on two sides of the baffle.

[0112] Further, as shown in the drawings, Figure 1 As shown, the piston pump further comprises a first thrust bearing 22 and a second thrust bearing 27, which are respectively arranged at the first end cover 12 and the second end cover 10, one end of the transmission shaft assembly is matched with the first thrust bearing 22 and arranged in the inner hole of the first end cover 12, and this end is a power input end, and the other end of the transmission shaft assembly is matched with the second thrust bearing 27. Two thrust bearings are arranged at the first end cover 12 and the second end cover 10, which are used for balancing the hydraulic pressure of the transmission shaft assembly.

[0113] According to a preferred embodiment of the present application, as shown in the drawings, Figures 12-14As shown, the transmission shaft assembly adopts a cross transmission structure, and the transmission shaft assembly comprises an input transmission shaft 11, a first transmission block 2, a first transmission shaft 3, a second transmission block 7 and a second transmission shaft 17 connected in sequence; the two end faces of the first transmission block 2 are provided with sliding grooves a and b arranged orthogonally; the two end faces of the second transmission block 7 are provided with sliding grooves c and d arranged orthogonally; one end of the input transmission shaft is a power input end matched with a first thrust bearing 22, and the other end is a flat square structure c matched with the sliding groove a; the first transmission shaft 3 is arranged in the inner cavity of a first piston structure 4, and the circumferential direction of the first transmission shaft 3 is uniformly provided with a plurality of linear ball groove b34s parallel to the axis for placing balls 15 matched with the linear ball groove a47 of the first piston structure 4; the two ends of the first transmission shaft 3 are further respectively provided with a flat square structure a and a flat square structure b matched with the sliding groove b and the sliding groove c respectively; the second transmission shaft 17 is arranged in the inner cavity of a second piston structure, and the circumferential direction of the second transmission shaft 17 is uniformly provided with a plurality of linear ball groove c174s parallel to the axis for placing balls matched with the linear ball groove of the second piston structure 18; one end of the second transmission shaft 17 is further provided with a flat square structure d matched with the sliding groove d; the other end of the second transmission shaft 17 is matched with a second thrust bearing 27; wherein, any sliding groove has a plurality of inner wall faces, part of the plurality of inner wall faces are arranged as transmission faces, and the rest are arranged as non-transmission faces, the transmission faces of the sliding grooves on the two end faces of the same transmission block are perpendicular to each other, the flat square structure a, the flat square structure b, the flat square structure c and the flat square structure d all have transmission faces and non-transmission faces matched with corresponding sliding grooves, the transmission face of any flat square structure is closely attached to the transmission face of the corresponding sliding groove, and the non-transmission face of any flat square structure has a gap with the non-transmission face of the corresponding sliding groove, during work, the input transmission shaft 11 and the first transmission shaft 3 can slide along the normal direction of the non-transmission face while transmitting torque through the transmission face, and the first transmission shaft 3 and the second transmission shaft 17 can also slide along the normal direction of the non-transmission face while transmitting torque through the transmission face.

[0114] For example, as Figure 13As shown in the drawings, the flat square structure c has a flat square structure c driving surface 111 and a flat square structure c non-driving surface 112, the flat square structure a has a flat square structure a driving surface 31 and a flat square structure a non-driving surface 32, and the sliding groove b matched with the flat square structure a has a sliding groove b driving surface 210 and a sliding groove b non-driving surface 211, wherein the flat square structure c driving surface 111 of the input driving shaft 11 and the flat square structure a driving surface 31 of the first driving shaft 3 are respectively tightly attached to the driving surfaces at the two ends of the first driving block 2 and are perpendicular to each other. Similarly, the flat square structure b has a flat square structure b driving surface 33, the flat square structure d has a flat square structure d driving surface 172 and a flat square structure d non-driving surface 171, and the sliding groove d of the second driving block 7 has a sliding groove d driving surface 72 and a sliding groove d non-driving surface 71. The other end of the second driving shaft 17 is provided as a smooth shaft 173 matched with the second thrust bearing 27.

[0115] That is, during operation, the input driving shaft 11 and the first driving shaft 3 can slide along the normal direction of the non-driving surface while transmitting torque through the driving surface, the coaxiality of the input driving shaft 11 and the first driving shaft 3 can be adjusted while transmitting torque, and the different coaxiality between the input driving shaft 11 and the first driving shaft 3 can be compensated. The first driving shaft 3 and the second driving shaft 17 can also compensate for the different coaxiality during processing, assembly and operation through the cross torque transmission structure. Therefore, the two cross torque transmission structures can reduce the coaxiality requirement of the driving shaft and the upper / lower pump core, reduce the number of part matching processing, improve the processing and assembly technology, and greatly save money and time cost.

[0116] It can be seen that the present application adopts the driving shaft, the driving block and the straight groove inner ball torque transmission to replace the previous through shaft transmission structure, realizes the decoupling of the rotation of the upper / lower two driving shafts, compensates for the relative displacement of the input driving shaft, the first driving shaft and the second driving shaft during processing, assembly and operation, and allows larger radial and axial deviation. At the same time, the cross torque transmission structure composed of the driving shaft and the driving block not only has the advantages of simple structure, convenient installation, zero rotation gap, high torque, high rigidity, high sensitivity, etc., but also greatly reduces the processing cost of the previous torque transmission through shaft.

[0117] In the above embodiment, as shown in the drawings, in order to better realize the coaxiality adjustment, any sliding groove is a rectangular groove. Figure 13

[0118] Preferably, one of the two inner wall surfaces of the rectangular groove arranged in parallel is provided as a driving surface, and the other two surfaces are non-driving surfaces.

[0119] In the above embodiment, in order to better transmit torque and better realize the adjustment of the coaxiality, the length of the driving surface is greater than the length of the non-driving surface.

[0120] ​In the above embodiment, in order to prevent the balls from falling out of the ball grooves, the cross transmission structure comprises a plurality of limiting assemblies, any linear ball groove on the first transmission shaft and the second transmission shaft corresponds to a limiting assembly, and the limiting assembly is arranged in the corresponding linear ball groove and used for limiting the balls from sliding out of the linear ball groove.

[0121] According to an embodiment of the present application, the limiting assembly is composed of a first limiting member and a second limiting member, and the first limiting member and the second limiting member are respectively arranged in the corresponding linear ball groove.

[0122] According to a specific embodiment of the present application, the first limiting member and the second limiting member are both pins b14.

[0123] It can be seen that the two groups of ball grooves on the first transmission shaft and the second transmission shaft correspond to the ball grooves of the first piston structure and the inner hole of the first piston structure respectively, the balls are placed in the ball grooves of the transmission shaft, and the ball limiting pins are used for limiting the balls. The first transmission shaft and the second transmission shaft drive the first piston structure and the second piston structure to rotate around the first bushing, the pump core support frame and the second bushing through the balls, and the piston structures are guided to axially reciprocate under the guide of the guide surface.

[0124] Further, each group of linear ball grooves is uniformly distributed in the circumferential direction of the corresponding transmission shaft, and all the linear ball grooves have the same length and depth.

[0125] Preferably, any linear ball groove is not filled with balls, and the length of the linear ball groove without placing balls is ΔL=h / π, wherein h is the stroke of the guide. Further preferably, the length of the linear ball groove b34 and the linear ball groove c174 is L=nD+h / π, wherein D is the diameter of the ball, and n is the number of balls, which is determined according to the carrying capacity of the ball and the torque required to be transmitted, and the specific setting is a technology known in the art.

[0126] Since the balls in the linear ball grooves are not fully filled in the grooves, and the initial positions of the balls on each groove are inconsistent, the balls will generate a tilting torque on the transmission shaft and the guide piston. This torque can be balanced by the first bushing, the pump core support frame and the second bushing of the piston pump.

[0127] Further, the first transmission shaft 3 and the second transmission shaft 17, the linear ball grooves, the ball grooves in the first piston structure 4 and the second piston structure 18, the flow distribution grooves and the profiles are all machined by one clamping respectively. The linear ball grooves in the linear ball grooves of the transmission shaft and the linear ball grooves in the piston structure are gapless, which not only ensures that the instantaneous flow of the upper / lower pump core always remains constant, but also can well eliminate the flow pulsation and pressure pulsation of the pump.

[0128] According to another preferred embodiment of the present application, as shown in Figures 15-19 As shown in the figure, the transmission shaft assembly can also be designed to include two transmission blocks 25, a plurality of limiting portions 23 and a transmission shaft 21, the two transmission blocks 25 are respectively arranged one-to-one with the first piston structure 4 and the second piston structure 18, the transmission block 25 is a hollow column structure with open ends, has an inner cavity 252, a pair of inner transmission grooves 253 are uniformly arranged on the inner cavity wall in the circumferential direction; a pair of outer transmission grooves 251 are uniformly arranged on the outer wall surface of the transmission block 25 in the circumferential direction, any inner transmission groove 253 and outer transmission groove 251 are arranged along the length direction of the transmission block 25, a pair of inner transmission grooves 253 and a pair of outer transmission grooves 251 are arranged orthogonally, the two transmission blocks 25 are also arranged in the inner cavities of the first piston structure 4 and the second piston structure 18 respectively, the outer transmission grooves 251 of the transmission block 25 are matched with the balls in the ball grooves of the corresponding piston structure; the transmission shaft 21 is symmetrically provided with a pair of shift forks 211a in the circumferential direction, the shift forks 211a are also arranged along the length direction of the transmission shaft 21; the transmission shaft 21 is arranged in the two transmission blocks 15 at the same time, the two transmission blocks 25 are arranged at intervals along the axis direction of the transmission shaft 21, the inner transmission grooves 253 of any transmission block 25 are matched with the shift forks 211a of the transmission shaft, the two ends of the transmission shaft 21 are matched with the first thrust bearing 22 and the second thrust bearing 27 respectively; the two ends of any transmission block 25 are provided with the limiting portions 23, the limiting portions 23 are also fixedly sleeved on the transmission shaft 21 (that is, the limiting portions 23 cannot move along the axis direction of the transmission shaft 21, and can rotate with the transmission shaft 21), the limiting portions 23 are used for limiting the movement of the two transmission blocks 25 along the axis direction of the transmission shaft 21; wherein, during work, the transmission shaft 21 drives the two transmission blocks 25 to rotate, the two transmission blocks 25 transmit the torque to the first piston structure 4 and the second piston structure 18 through the balls, so that the first piston structure 4 and the second piston structure 18 rotate in the circumferential direction.

[0129] That is, the transmission shaft assembly of the present application can also adopt an orthogonal torque transmission structure.

[0130] In the embodiment of the present application, the two sides of the transmission shaft 21 are bearing mounting columns 210 and 212, and a pair of shift forks 211a protrude in the radial direction in the middle.

[0131] The embodiment of the present application increases a transmission block between a transmission through shaft and a piston, a pair of shift forks are arranged in a hole in the piston, ball grooves are opened on the shift forks, a pair of shift forks are arranged on the transmission through shaft, and transmission grooves are arranged on the transmission block in a radial direction and orthogonally, the outer grooves are matched with the balls in the shift fork grooves, and the inner grooves are matched with the shift forks of the transmission through shaft.

[0132] Preferably, to prevent the balls 26 from falling out, ball plugs 24 are added at both ends of the transmission block 25 to block the balls.

[0133] Preferably, the two transmission blocks 25, the piston structure and the transmission through shaft 21 are coaxial; and / or the transmission block 25 is a hollow cylindrical structure with both ends open.

[0134] It can be seen that the embodiment of the present application proposes a new baffle type piston structure, a new double-sided flow distribution structure and a new transmission shaft assembly structure (cross transmission torque structure and orthogonal transmission torque structure).

[0135] Specifically,

[0136] The embodiment of the present application proposes a new baffle type piston structure, the piston as a whole has a large outer diameter, a small inner diameter and no inner wall surface, the middle cylindrical surface is a flow distribution surface, and two pairs of inlets and outlets are symmetrically distributed on both sides. The oil liquid directly enters the piston cavity without passing through a complex flow channel, thereby increasing the self-suction capacity of the pump; the inlet and outlet end surfaces of the piston are designed with chamfers, which can effectively reduce the hydraulic loss caused by the outer diameter end surface when the piston rotates; the oil liquid entering the piston cavity almost does not have a circumferential rotation movement, at the same time, the axial speed of the oil liquid is small due to the small piston stroke, and the kinetic energy loss of the oil liquid is extremely small, thereby the energy conversion rate of the pump is high; at high speed, the oil liquid can quickly follow the axial movement of the piston and timely fill the piston cavity, thereby greatly enhancing the anti-cavitation capacity of the pump. The piston is internally provided with a through hole, a pair of shift forks are arranged in the radial direction of the through hole, and four ball grooves are uniformly distributed on the shift forks for torque transmission.

[0137] The embodiment of the present application provides a bidirectional flow distribution structure, which mainly comprises a bidirectional flow distribution integrated baffle type piston, a baffle type liner, an integrated cylinder body and the like. The bidirectional flow distribution integrated baffle type piston is an integrated structure of a cam and a piston, the cam is in the middle of the piston, the cam is symmetrically extended with an inner and outer cylindrical sleeve on both sides, the baffle type liner is embedded and installed in the baffle type piston, and a closed volume is formed. A pair of oil distribution ports are respectively arranged on the sleeve and the boss, and the two pairs of oil distribution ports are in orthogonal positions. The oil distribution port on the outer sleeve is an oil suction port, the oil distribution port on the inner sleeve is an oil discharge port, a through hole is arranged in the center of the inner sleeve, a ball groove and a high-pressure groove are arranged in the through hole in an orthogonal manner, a cross transmission / torque orthogonal transmission structure passes through the through hole, and the piston is rotated by the ball. The piston and the double-sided guide rail are integrated to form an integrated guide rail piston, the cam is in the middle of the piston, compared with the previous guide rail and roller structure which is concentratedly distributed on one side, the roller can be distributed on the outer side of the piston sleeve, the axial distance of the piston can be fully utilized, the axial length of the pump can be effectively shortened, and the volume of the pump is reduced; the piston and the liner are both baffle structures, the liner replaces the traditional cylinder part, and the piston and the liner are hollowed out in the middle and are circumferentially slotted, so that the weight of the pump is greatly reduced, and the power-weight ratio of the pump is improved; meanwhile, the piston and the liner are both baffle structures, the influence on the oil liquid is small when the piston and the liner rotate, the oil stirring loss is reduced, and the mechanical efficiency is high; the piston is bidirectionally distributed, the oil suction port and the oil discharge port are distributed on different cylinders, the distance between the oil ports is indirectly increased, the sealing length is increased, the leakage amount is effectively reduced, and the volumetric efficiency of the pump is improved.

[0138] The embodiment of the present application provides a cross transmission structure, the transmission shaft is replaced by upper / lower two transmission shafts, a transmission block is arranged between the input transmission shaft and the first transmission shaft, and between the first transmission shaft and the second transmission shaft, and a ball groove is formed in each of the upper / lower two transmission shafts. A pair of shift forks are arranged in the inner hole of the piston in a radial direction, and a ball groove is formed in the shift fork. The grooves of the transmission shafts and the balls in the shift fork groove are matched, and two limiting pins are arranged on the upper / lower two transmission shafts to block the balls, so as to prevent the balls in the piston groove from falling out. When working, the input transmission shaft drives the transmission block to rotate, the transmission block drives the first transmission shaft to rotate, the first transmission shaft transmits torque to the first piston structure through the balls, the piston rotates in a circumferential direction, and reciprocates in an axial direction under the action of the guide rail, and the lower pump core is transmitted in the same way. In this transmission structure, the different shaft degrees between the upper / lower pump cores and the transmission shaft exist and can be adjusted by the transmission block, so that the machining precision requirement of the parts is reduced.

[0139] The embodiment of the present application provides a kind of orthogonal transmission torque structure, and transmission block is increased between transmission through shaft and piston, and a pair of shift forks is arranged in the radial direction in the inner hole of piston, and ball groove is opened on shift fork.The bearing mounting column of transmission through shaft is on both sides, and a pair of shift forks is projected in the radial direction along middle light axle.The transmission groove of transmission block is arranged in the radial direction orthogonally, and the ball in the groove of piston shift fork is matched with the groove on the outside, and the groove on the inside is matched with the shift fork of transmission through shaft.To prevent the ball in the radial direction of piston groove from coming out, the plug block of transmission block is increased and is blocked.Working, transmission through shaft drives transmission block to rotate (no relative axial movement between the two), and transmission block passes through ball and transmits torque to piston, so that piston rotates in the circumferential direction, and reciprocating motion is carried out along the axial direction under the action of guide rail.The orthogonal transmission torque structure is used, transmission through shaft and piston are stressed in orthogonal direction, and there is no radial component force, so that piston does not cause extrusion to copper bushing.Even if transmission through shaft and the structure of first / second piston exist small scale different shafts, it can be adjusted by the self-adapting of transmission block, so that the coaxiality requirement of transmission shaft and upper / lower pump core can be reduced, the number of parts matching machining is reduced, the process of machining and assembly is improved, money and time cost can be greatly saved.

[0140] In summary, the piston sleeve and double-sided guide rail of the double-motion-freedom piston pump of the present application are integrated, the rollers can be distributed on the outside of the piston sleeve, the axial distance of the piston can be fully utilized, the axial length of the pump can be effectively shortened, the volume and weight of the pump are reduced, and the power-to-weight ratio of the pump is improved; the piston and the liner are both baffle structures, the liner replaces the traditional cylinder part, and the piston and the liner are hollowed out and circumferentially slotted, which greatly reduces the weight of the pump; the piston and the liner are both baffle structures, the resistance experienced by the integrated guide rail piston during rotation and reciprocating motion is reduced, the power loss of oil stirring is reduced, and the mechanical efficiency of the pump is improved; the piston is double-sided flow distribution, the oil suction port and the oil discharge port are distributed on different cylinders, the distance between the oil ports is indirectly increased, the sealing length is increased, the leakage is effectively reduced, and the volumetric efficiency of the pump is improved; the oil suction port of the piston cavity is arranged on the guide rail piston sleeve and directly communicates with the oil, the oil can enter the piston cavity without passing through any flow channel, and the self-priming capacity of the pump is effectively increased. The piston is a baffle structure, the oil entering the piston cavity almost does not have circumferential rotational motion, the axial speed of the oil is small due to the small piston stroke, the kinetic energy loss of the oil is extremely small, and the energy conversion rate of the pump is high. The piston is a baffle structure, at high speed, the oil can quickly follow the axial motion of the piston and timely fill the piston cavity, which greatly enhances the anti-cavitation capacity of the pump. With the structure of the present application, when the piston cavity is in the oil compression stroke, the liner is slightly deformed under the action of high-pressure oil, the gap between the liner and the piston is reduced, the leakage is reduced, and the volumetric efficiency is improved. This gap compensation structure is also applicable at high temperature.

[0141] The application can also realize decoupling of the rotary motion of the two pump cores through the cross transmission / torque orthogonal transmission structure, greatly reduces the coaxiality requirement of the two pump cores, and the transmission structure is simpler, and the problem of piston eccentric wear under high speed and high pressure caused by the misalignment of the series pump cores can be solved. Specifically, compared with the yoke roller transmission structure, the orthogonal / cross transmission structure has small volume, the transmission structure is arranged in the piston, and the axial length of the pump is not affected. The orthogonal / cross transmission structure has light weight, short rotation radius, small moment of inertia, good start-stop performance, and good control performance of the pump. Compared with the external yoke roller transmission structure, the orthogonal / cross transmission structure is distributed in the piston, has very small oil stirring loss, and is suitable for high-speed working conditions. The orthogonal / cross transmission structure realizes the decoupling of the rotary motion of the upper and lower pump cores, reduces the coaxiality requirement of the upper and lower pump cores, reduces the machining precision requirement, reduces the machining cost, and improves the economic benefit.

[0142] In the description of the application, it should be understood that the orientation words such as "front, back, up, down, left, right", "transverse, vertical, perpendicular, horizontal" and "top, bottom" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the application and simplifying the description, and in the absence of contrary description, these orientation words do not indicate and imply that the devices or elements referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the scope of protection of the application; the orientation words "inner, outer" refer to the inner and outer of the contour of each component itself.

[0143] For the convenience of description, spatial relative terms such as "above", "upper", "on", "upper surface", "upper", etc. can be used herein to describe the spatial positional relationship of one device or feature with other devices or features as shown in the drawings. It should be understood that the spatial relative terms are intended to include different orientations in use or operation in addition to the orientation of the devices described in the drawings. For example, if the devices in the drawings are inverted, the device described as "above" or "above" other devices or structures will be positioned "below" or "below" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below" orientations. The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein are interpreted accordingly.

[0144] In addition, it should be noted that the use of the words "first", "second", etc. to define parts only facilitates the differentiation of corresponding parts, and the above words have no special meaning unless otherwise stated, and therefore cannot be understood as a limitation on the scope of protection of the application.

[0145] The above description is only the preferred embodiment of the present application, and is not intended to limit the present application. The present application can have various changes and modifications for those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A dual-motion-degree-of-freedom piston pump, the piston pump comprising: The front end cover, the pump shell and the rear end cover are sequentially fixed to form a pump shell structure, and the piston pump further comprises: a transmission shaft assembly; a pump core arranged in the pump shell structure and rotatably arranged on the transmission shaft assembly, the pump core adopts an integrated series connection structure of upper and lower two groups of pump cores, the series connection structure comprises first and second piston structures which are rotatably arranged on the transmission shaft assembly in the axial direction of the transmission shaft assembly, the first and second piston structures both adopt an integrated structure of a piston and a cam guide rail, the cam guide rail is located in the middle of the piston, two sleeve structures symmetrically protrude from both sides of the cam guide rail, any sleeve structure comprises an outer sleeve and an inner sleeve located in the outer sleeve, a plurality of oil suction ports are circumferentially formed in the outer sleeve, a plurality of oil discharge ports are circumferentially formed in the inner sleeve, and any oil suction port and any oil discharge port are staggered; 2. A dual-motion-degree-of-freedom piston pump according to claim 1, wherein, the outer sleeve and the inner sleeve form an annular cavity therebetween, the annular cavities of the two sleeve structures are not connected, and the inner sleeves on both sides are connected and form an inner cavity of the piston structure. The series connection structure further comprises first and second bushings and a pump core support frame, the first bushing, the first piston structure, the pump core support frame, the second piston structure, and the second bushing are coaxially arranged along the axis of the transmission shaft assembly, the first and second bushings both comprise a baffle and a bushing sleeve arranged on the baffle, the bushing sleeve is composed of a bushing outer sleeve and a bushing inner sleeve located in the bushing outer sleeve, an annular cavity is formed between the bushing inner and outer sleeves, a plurality of oil distribution ports are circumferentially distributed on the bushing sleeve, any oil distribution port penetrates through the bushing outer sleeve and the bushing inner sleeve, the baffle has an inner hole penetrating through the baffle, the inner hole is connected with the bushing inner sleeve to form an inner cavity of the bushing; the pump core support frame adopts an integrated cylinder structure, comprises a pump core support frame body, the pump core support frame body is fixedly connected with the pump shell, an oil discharge flow channel is formed in the pump core support frame body, first and second support arm bushing assemblies protrude from both ends of the pump core support frame body, the two assemblies are arranged at a preset angle, the first support arm bushing assembly is composed of a first support arm assembly and a first support sleeve, the second support arm bushing assembly is composed of a second support arm assembly and a second support sleeve, the first and second support sleeves are the same as the bushing sleeve structure, and the inner sleeves of the first and second support sleeves are both connected with the oil discharge flow channel to form an inner cavity of the pump core support frame; The first bushing, the first piston structure and the first support arm bushing assembly are matched, the second bushing, the second piston structure and the second support arm bushing assembly are matched, the piston structure is arranged between the corresponding bushing and the support arm bushing assembly, and the inner cavity of the first bushing, the first piston structure, the pump core support frame and the second bushing are sequentially connected in communication.

3. A dual-motion-degree-of-freedom piston pump according to claim 2, wherein, The support arm assembly is fixedly connected with the baffle of the corresponding bushing, the bushing sleeve is embedded in the annular cavity of the sleeve on one side of the cam rail to form a closed oil cavity, the corresponding support sleeve is embedded in the annular cavity of the sleeve on the other side of the cam rail to form another closed oil cavity, and the four closed oil cavities in series structure work regularly to suck and discharge oil.

4. A dual-motion-degree-of-freedom piston pump according to claim 3, wherein, The series structure further comprises a first end cover and a second end cover, the first end cover is fixedly connected with the baffle of the first bushing, the first end cover has an inner hole penetrating through the first end cover and communicating with the inner hole on the baffle, the first end cover and the bushing sleeve on the baffle are respectively arranged on both sides of the baffle, and the second end cover is fixedly connected with the baffle of the second bushing and arranged on both sides of the baffle with the bushing sleeve on the baffle.

5. A dual-motion-degree-of-freedom piston pump according to claim 1, wherein, The piston pump further comprises a first thrust bearing and a second thrust bearing, which are respectively arranged at the first end cover and the second end cover, one end of the transmission shaft assembly is matched with the first thrust bearing and arranged in the inner hole of the first end cover, and the other end of the transmission shaft assembly is matched with the second thrust bearing.

6. A dual-motion-degree-of-freedom piston pump according to claim 5, wherein, In the first piston structure and the second piston structure, for any sleeve structure, a pair of oil suction ports are symmetrically arranged on the outer sleeve, a pair of oil discharge ports are symmetrically arranged on the inner sleeve, and the pair of oil suction ports and the pair of oil discharge ports are arranged orthogonally; for any bushing sleeve, a pair of symmetrical oil distribution ports are arranged on the bushing sleeve along the circumferential direction, any oil distribution port is composed of an oil distribution port on the outer sleeve of the bushing and an oil distribution port on the inner sleeve of the bushing, and the oil distribution ports on the outer sleeve of the bushing and the inner sleeve of the bushing are arranged in parallel.

7. A dual-motion-degree-of-freedom piston pump according to claim 5 or 6, characterised in that, Any oil distribution port further extends to the free end of the corresponding sleeve.

8. A dual-motion-degree-of-freedom piston pump according to claim 7, wherein, The end face of the oil suction port is designed as an inclined surface, wherein the outer opening area of the oil suction port is larger than the inner opening area; and / or the end face of the oil discharge port is designed as an inclined surface, wherein the outer opening area of the oil discharge port is larger than the inner opening area.

9. A dual-motion-degree-of-freedom piston pump according to claim 1, wherein, The cross-sectional area of the oil suction port is larger than that of the oil discharge port.

10. A dual-motion-degree-of-freedom piston pump according to claim 9, wherein, A plurality of shift forks are symmetrically arranged on the inner cavity of the piston structure along the radial direction, linear ball grooves are arranged on the shift forks, and the linear ball grooves are used for ball torque transmission.

11. A dual-motion-degree-of-freedom piston pump according to claim 2, wherein A high-pressure flow channel is processed on the inner cavity wall except the shift forks, and the high-pressure flow channel communicates with the oil discharge port and the oil discharge flow channel.

12. A dual-motion-degree-of-freedom piston pump according to claim 11, wherein, The pump core support frame body is in the shape of a circular truncated cone, an annular groove is arranged on the circumferential side wall of the circular truncated cone, a body oil discharge port is arranged on the annular groove, and the body oil discharge port communicates with the oil discharge flow channel in the body, and the annular groove and the pump shell form a high-pressure cavity. A plurality of oil passage grooves are arranged on the pump core support frame body along the circumferential direction, any oil passage groove is arranged along the axial direction of the pump core support frame body and does not communicate with the oil discharge flow channel, and the oil passage groove is used to realize oil circulation in the entire pump shell.

13. A dual-motion-degree-of-freedom piston pump according to claim 2, wherein The first support arm assembly and the second support arm assembly are both composed of two symmetrically arranged support arms; the cam guide rail is a double-sided cam guide rail; the series structure is a double-sided flow distribution structure, and the double-sided flow distribution structure further comprises a first roller frame assembly and a second roller frame assembly, the first roller frame assembly is matched with the first support arm assembly and the first piston structure, the second roller frame assembly is matched with the second support arm assembly and the second piston structure, the first roller frame assembly and the second roller frame assembly both comprise two groups of roller assemblies, the two groups of roller assemblies are arranged in the length direction of the corresponding support arm assembly, any roller assembly comprises a roller frame and a plurality of rollers, the roller frame is fixedly connected with the corresponding two support arms, the plurality of rollers are arranged on the inner wall of the roller frame in the circumferential direction of the roller frame, and the corresponding double-sided cam guide rail is clamped between the plurality of rollers of the two groups of roller assemblies; wherein, when the piston structure rotates, the rollers of the two groups of roller assemblies can move along the circumferences of the two sides of the double-sided cam guide rail, respectively.

14. A dual-motion-degree-of-freedom piston pump according to claim 9, wherein, The transmission shaft assembly comprises an input transmission shaft, a first transmission block, a first transmission shaft, a second transmission block and a second transmission shaft which are sequentially connected; the two end faces of the first transmission block are provided with sliding grooves a and b which are orthogonally distributed; the two end faces of the second transmission block are provided with sliding grooves c and d which are orthogonally distributed; one end of the input transmission shaft is a power input end which is matched with a first thrust bearing, and the other end is a flat square structure c which is matched with the sliding groove a; the first transmission shaft is arranged in the inner cavity of the first piston structure, and a plurality of straight linear ball grooves which are parallel to the axis are uniformly distributed in the circumferential direction of the first transmission shaft for placing balls and matching with the straight linear ball grooves of the first piston structure; the two ends of the first transmission shaft are further respectively provided with a flat square structure a and a flat square structure b which are matched with the sliding groove b and the sliding groove c, respectively; the second transmission shaft is arranged in the inner cavity of the second piston structure, and a plurality of straight linear ball grooves which are parallel to the axis are uniformly distributed in the circumferential direction of the second transmission shaft for placing balls and matching with the straight linear ball grooves of the second piston structure; one end of the second transmission shaft is further provided with a flat square structure d which is matched with the sliding groove d; the other end of the second transmission shaft is matched with a second thrust bearing; Wherein, any sliding groove has a plurality of inner wall faces, part of the plurality of inner wall faces are provided as transmission faces, and the remaining part are provided as non-transmission faces, the transmission faces of the sliding grooves on the two end faces of the same transmission block are perpendicular to each other, the flat square structure a, the flat square structure b, the flat square structure c and the flat square structure d all have transmission faces and non-transmission faces which are matched with the corresponding sliding grooves, the transmission face of any flat square structure is closely attached to the transmission face of the corresponding sliding groove, and the non-transmission face of any flat square structure has a gap with the non-transmission face of the corresponding sliding groove, during work, the input transmission shaft and the first transmission shaft can slide along the normal direction of the non-transmission face while transmitting torque through the transmission face, and the first transmission shaft and the second transmission shaft can also slide along the normal direction of the non-transmission face while transmitting torque through the transmission face.

15. A dual-motion-degree-of-freedom piston pump according to claim 14, wherein Any sliding groove is a rectangular groove, one group of two inner wall faces which are parallel to each other of the rectangular groove are provided as transmission faces, and the remaining two faces are non-transmission faces.

16. A dual-motion-degree-of-freedom piston pump according to claim 14 or 15, characterised in that The length of the transmission face is greater than the length of the non-transmission face.

17. A dual-motion-degree-of-freedom piston pump according to claim 14, wherein Any of the straight linear ball tracks is not filled with balls, and the length of the straight linear ball track without balls is ΔL, ΔL = h / π, wherein h is the guide rail stroke of the piston pump.

18. A dual-motion-degree-of-freedom piston pump according to claim 17, wherein, The length of any of the straight linear ball tracks is L: L = nD + h / π Wherein, L is the length of the straight linear ball track, D is the diameter of the ball, n is the number of balls, and h is the guide rail stroke.

19. A dual-motion-degree-of-freedom piston pump according to claim 9, wherein, The transmission shaft assembly comprises: Two transmission blocks are respectively arranged one-to-one with the first piston structure and the second piston structure, the transmission block is a hollow cylindrical structure with two open ends, a pair of inner transmission grooves are uniformly arranged on the inner cavity wall of the transmission block in the circumferential direction; a pair of outer transmission grooves are uniformly arranged on the outer wall surface of the transmission block in the circumferential direction, any inner transmission groove and outer transmission groove are arranged along the length direction of the transmission block, the pair of inner transmission grooves and the pair of outer transmission grooves are arranged orthogonally, any transmission block is arranged in the inner cavity of the corresponding piston structure, the transmission groove on the outer side of the transmission block is matched with the ball in the ball track of the corresponding piston structure; A transmission shaft is arranged on the transmission block, the transmission shaft is arranged in the inner cavities of the two transmission blocks, the two transmission blocks are arranged in the axial direction of the transmission shaft, the inner transmission groove of any transmission block is matched with the shift fork of the transmission shaft, the transmission shaft is matched with the first thrust bearing and the second thrust bearing at both ends respectively; A plurality of limiting parts are arranged at both ends of any transmission block, the limiting part is also fixedly sleeved on the transmission shaft, and the limiting part is used to limit the movement of the two transmission blocks in the axial direction of the transmission shaft. Wherein, during work, the transmission shaft drives the two transmission blocks to rotate, the two transmission blocks are distributed to transmit torque to the first piston structure and the second piston structure through the balls, so that the first piston structure and the second piston structure rotate in the circumferential direction.

20. A dual-motion-degree-of-freedom piston pump according to claim 19, wherein, The two transmission blocks, the first piston structure, the second piston structure and the transmission shaft are coaxially arranged; and / or the hollow cylindrical structure with two open ends is a hollow cylindrical structure with two open ends.

Images