A straight-shaft swash plate type hydraulic piston pump core

Abstract

The application provides a straight-shaft swash plate type hydraulic plunger pump core, belonging to the technical field of hydraulic plunger pumps, which comprises a cylinder body, a flow distribution disc, a swash plate and a plunger, the plunger is provided with a plunger cavity with an opening facing the plunger hole, a round tubular plunger core is arranged in the plunger cavity, one end of the plunger core is provided with a connecting plate for sealing the opening of the plunger cavity, and a plurality of circumferentially distributed pressure reduction flow channels are formed in the outer side wall of the plunger core; when the plunger pump is pumping, the oil in the plunger hole flows into the plunger cavity through the pressure reduction flow channels after pressure reduction; when the plunger is pumping, the oil in the plunger cavity flows into the plunger hole through the pressure reduction flow channels under the action of negative pressure; the oil flows through the pressure reduction flow channels in the pumping state and the oil suction state of the plunger, the oil contacts the inner wall of the plunger cavity when flowing through the pressure reduction flow channels, so that the plunger is cooled, meanwhile, the pressure in the plunger cavity is reduced when the plunger pump is pumping by using the pressure reduction flow channels, so that the plunger is prevented from swelling due to excessive oil pressure.

Description

Technical Field

[0001] The invention belongs to the technical field of hydraulic plunger pumps, and in particular relates to a pump core of a straight-axis swash plate hydraulic plunger pump. Background Art

[0002] The straight-axis swash plate hydraulic piston pump is a commonly used hydraulic pump, mainly composed of a cylinder body, a plunger, a swash plate, a port plate and a drive shaft. The plungers are evenly distributed axially in the plunger holes of the cylinder body. The swash plate and the port plate are fixed, and the cylinder body is driven to rotate by an external drive device through the drive shaft. As the pump shaft rotates, each plunger continuously reciprocates to absorb and discharge oil. The coordinated action of multiple plungers forms a continuous flow output. The swash plate plunger pump has the advantages of high rated pressure, compact structure, high efficiency and smooth operation.

[0003] During the working process, the plunger and the cylinder body are constantly rubbing against each other. Under the action of friction, the temperature of the plunger gradually increases. In order to reduce the thermal expansion of the plunger when the temperature changes, the plunger is usually a hollow plunger. At the same time, the hollow plunger design allows oil to enter its interior, thereby effectively dissipating heat, slowing down the heating rate of the plunger, and keeping the temperature of the plunger within an acceptable range, preventing wear and damage caused by overheating of the plunger.

[0004] However, when the plunger is pumping oil, the oil pressure inside the cylinder and the hollow plunger increases. The larger oil pressure acts on the side wall of the hollow plunger from the inside of the hollow plunger, causing the hollow plunger to bulge outward, thereby increasing the friction between the hollow plunger and the cylinder. After long-term use, the hollow plunger and the cylinder will wear out, and the sealing between the plunger and the cylinder will be reduced, which in turn affects the oil pumping pressure. Summary of the Invention

[0005] In view of the above situation, in order to overcome the defects of the prior art, the present invention provides a straight-axis swash plate hydraulic plunger pump core, which at least partially solves the above problems.

[0006] The technical solution adopted by the present invention is as follows: The present invention proposes a straight-axis swash plate hydraulic plunger pump core, comprising:

[0007] A cylinder body, wherein a plurality of plunger holes evenly distributed in the circumferential direction are formed on the cylinder body, and a swash plate and a return plate are provided at one end of the cylinder body;

[0008] The number of plungers corresponds to the number of the plunger holes, one end of the plunger slides in the plunger hole, the other end of the plunger is provided with a plunger ball head, the plunger ball head is connected to a sliding shoe, the sliding shoe is connected to the return plate and is restricted by the return plate between the swash plate and the return plate. Under the constraint of the swash plate, the cylinder body rotates to enable the plunger to reciprocate in the plunger hole to achieve oil suction or oil pumping;

[0009] The plunger is provided with a plunger cavity with an opening toward the plunger hole, wherein a cylindrical core plug is provided in the plunger cavity, and a connecting plate is provided at one end of the core plug for sealing the opening of the plunger cavity;

[0010] The outer side wall of the column core plug is provided with a plurality of circumferentially distributed pressure-reducing channels, one end of the pressure-reducing channel passes through the connecting plate and is connected to the plunger hole, and the other end of the pressure-reducing channel is connected to the plunger cavity. When the plunger pumps oil, the oil in the plunger hole is decompressed through the pressure-reducing channel and then flows into the plunger cavity.

[0011] Furthermore, a lubrication groove for storing oil is provided on a surface of the sliding shoe in contact with the swash plate, so that a lubricating oil layer can be formed between the sliding shoe and the swash plate when the sliding shoe rubs against the swash plate.

[0012] Furthermore, an oil storage tank is provided on the side where the slipper is connected to the plunger, and a second oil delivery hole connecting the oil storage tank and the lubrication groove is also provided on the slipper. A first oil delivery hole connecting the plunger cavity and the oil storage tank is opened on the plunger. When the cylinder body pumps oil, the oil in the plunger cavity can be transported to the lubrication groove.

[0013] Furthermore, a plurality of buffer grooves are provided in the lubrication groove, and an elastic diaphragm is provided at the opening of the buffer groove. When the oil pressure in the lubrication groove increases, the elastic diaphragm elastically expands into the buffer groove to store oil. When the oil pressure in the lubrication groove decreases, the elastic diaphragm pushes out the stored oil to replenish the oil.

[0014] Furthermore, the pressure reducing flow channel is configured as an S-shaped pressure reducing flow channel.

[0015] Furthermore, an external thread is provided on the side of the connecting plate, and an internal thread is provided at the opening of the plunger, and the connecting plate is connected to the plunger via the thread.

[0016] Furthermore, a wrench slot for connecting with a wrench is provided on an end surface of the connecting plate away from the column plug.

[0017] Furthermore, the connecting plate is provided with first oil holes corresponding to the number of the pressure reducing flow channels, and the pressure reducing flow channels are connected with the plunger holes through the first oil holes.

[0018] Furthermore, the end of the column plug away from the connecting plate is provided with second oil holes corresponding to the number of the pressure reducing flow channels, and the pressure reducing flow channels are connected to the plunger cavity through the second oil holes.

[0019] Furthermore, a distribution plate is provided at one end of the cylinder body away from the swash plate.

[0020] The beneficial effects achieved by the present invention using the above structure are as follows:

[0021] 1. By arranging a core plug in the plunger cavity of the plunger and arranging a pressure reducing flow channel on the core plug, when the plunger pumps oil, the oil in the plunger hole is decompressed through the pressure reducing flow channel and flows into the plunger cavity; when the plunger absorbs oil, the oil in the plunger cavity flows into the plunger hole through the pressure reducing flow channel under the action of negative pressure. In both the oil absorbing state and the oil pumping state of the plunger, the oil will flow through the pressure reducing flow channel. When the oil flows in the pressure reducing flow channel, it contacts the inner wall of the plunger cavity, thereby cooling the plunger; at the same time, the pressure reducing flow channel is used to reduce the pressure inside the plunger cavity when the plunger pumps oil, thereby avoiding expansion of the plunger due to excessive oil pressure.

[0022] 2. By setting a buffer groove connected to the lubrication groove on the sliding shoe, when the plunger is in the oil pumping state, the oil pressure in the lubrication groove increases, the elastic diaphragm elastically expands into the buffer groove, and stores excess oil; when the plunger is in the oil suction state, the oil pressure in the lubrication groove decreases. At this time, the elastic diaphragm pushes out the stored oil and replenishes the oil into the lubrication groove; when the plunger is in the oil suction or oil pumping state, there is always sufficient oil in the lubrication groove to maintain the lubricating oil layer between the sliding shoe and the swash plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic structural diagram of a pump core of a straight-axis swash plate hydraulic plunger pump proposed in an embodiment of the present invention;

[0024] Figure 2 This is a structural schematic diagram of a straight-axis swash plate hydraulic plunger pump according to an embodiment of the present invention, wherein the pump core is not equipped with a return plate;

[0025] Figure 3 A cross-sectional view of a cylinder and a plunger in a pump core of a straight-axis swash plate hydraulic plunger pump according to an embodiment of the present invention;

[0026] Figure 4 A partial cross-sectional schematic diagram of a plunger in a pump core of a straight-axis swash plate hydraulic plunger pump proposed in an embodiment of the present invention;

[0027] Figure 5 This is a schematic structural diagram of a cylindrical core plug in a pump core of a straight-axis slant-plate hydraulic piston pump proposed in an embodiment of the present invention;

[0028] Figure 6 A schematic diagram of the state of the plunger in a pump core of a straight-axis swash plate hydraulic plunger pump proposed in an embodiment of the present invention when absorbing and pumping oil;

[0029] Figure 7 This is a schematic structural diagram of the contact surface between the sliding shoe and the swash plate in a pump core of a straight-axis swash plate hydraulic plunger pump proposed in an embodiment of the present invention.

[0030] Among them, 1. cylinder body; 101. plunger hole; 11. connecting shaft; 12. distribution plate; 2. plunger; 21. plunger ball head; 201. plunger cavity; 202. first oil hole; 3. sliding shoe; 31. elastic diaphragm; 301. oil storage tank; 302. second oil hole; 303. lubrication groove; 304. buffer groove; 4. inclined plate; 5. core plug; 501. pressure reducing channel; 502. first oil hole; 503. second oil hole; 504. wrench slot; 51. connecting plate; 6. return plate.

[0031] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0033] In the description of the present invention, it should be understood that terms such as "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limiting the present invention.

[0034] like Figure 1 As shown, the present invention proposes a straight-axis swash plate hydraulic plunger pump core, which includes a cylinder body 1, a connecting shaft 11, a distribution plate 12, a plunger 2, a swash plate 4 and a return plate 6.

[0035] One end of the connecting shaft 11 is connected to the cylinder body 1, and the other end of the connecting shaft 11 is connected to an external drive device. The cylinder body 1 is provided with a plurality of plunger holes 101 evenly distributed around the circumference. The valve plate 12 and the swash plate 4 are respectively arranged at both ends of the cylinder body 1. The number of plungers 2 corresponds to the number of plunger holes 101. One end of the plunger 2 slides in the plunger hole 101. The other end of the plunger 2 is provided with a plunger ball head 21. The plunger ball head 21 is connected to a slipper 3. The slipper 3 is connected to the return plate 6. The slipper 3 is restricted by the return plate 6 between the swash plate 4 and the return plate 6, ensuring that the slipper 3 can slide closely on the surface of the swash plate 4.

[0036] The return disc 6 is connected to the connecting shaft 11 via a ball joint, so that the return disc 6 can rotate when subjected to a lateral force, thereby adapting to the reciprocating motion of the plunger 2 in the cylinder body 1 .

[0037] The external driving device drives the cylinder body 1 to rotate through the connecting shaft 11. As the cylinder body 1 rotates, the plunger 2 is constrained by the swash plate 4 and the return plate 6 to reciprocate in the plunger hole 101 to suck and pump oil.

[0038] The oil is diverted by the distribution plate 12 so that the plunger hole 101 for pumping oil and the plunger hole 101 for sucking oil are separated from each other, and the pumping oil and the sucking oil are concentrated respectively.

[0039] The plunger 2 is provided with a plunger cavity 201 with an opening facing the plunger hole 101 . The oil in the plunger hole 101 can enter the plunger cavity 201 and cool the plunger 2 along the inner side.

[0040] Combine Figure 4 and Figure 5 As shown, a cylindrical core plug 5 is provided in the plunger cavity 201. A connecting plate 51 is provided at one end of the core plug 5 for sealing the opening of the plunger cavity 201. A plurality of circumferentially distributed pressure-reducing channels 501 are provided on the outer wall of the core plug 5. The pressure-reducing channels 501 are sealed by the inner wall of the plunger cavity 201. One end of the pressure-reducing channel 501 passes through the connecting plate 51 and communicates with the plunger hole 101, and the other end of the pressure-reducing channel 501 communicates with the plunger cavity 201.

[0041] When the plunger 2 pumps oil, the oil in the plunger hole 101 is decompressed through the pressure reducing channel 501 and flows into the plunger cavity 201. When the plunger 2 absorbs oil, the oil in the plunger cavity 201 flows into the plunger hole 101 through the pressure reducing channel 501 under the action of negative pressure. In the oil absorbing state and the oil pumping state of the plunger 2, the oil will flow through the pressure reducing channel 501. When the oil flows in the pressure reducing channel 501, it contacts the inner wall of the plunger cavity 201, thereby cooling the plunger 2. At the same time, the pressure reducing channel 501 is used to reduce the pressure inside the plunger cavity 201 when the plunger 2 pumps oil, so as to avoid the expansion of the plunger 2 due to excessive oil pressure.

[0042] In a specific embodiment, the connecting plate 51 is provided with first oil holes 502 corresponding to the number of the pressure-reducing flow channels 501, and the pressure-reducing flow channels 501 are connected to the plunger hole 101 through the first oil holes 502. The end of the column core plug 5 away from the connecting plate 51 is provided with second oil holes 503 corresponding to the number of the pressure-reducing flow channels 501, and the pressure-reducing flow channels 501 are connected to the plunger cavity 201 through the second oil holes 503.

[0043] Combine Figure 6 and Figure 7As shown, a lubrication groove 303 for storing oil is provided on the side of the sliding shoe 3 that contacts the swash plate 4. When the sliding shoe 3 rubs against the swash plate 4, a lubricating oil layer can be formed between the sliding shoe 3 and the swash plate 4, thereby playing a lubricating role and reducing the wear of the sliding shoe 3 and the swash plate 4.

[0044] Furthermore, an oil storage tank 301 is provided on one side of the sliding shoe 3 connected to the plunger 2, and a second oil delivery hole 302 is provided on the sliding shoe 3 to connect the oil storage tank 301 and the lubrication groove 303. A first oil delivery hole 202 is provided on the plunger 2 to connect the plunger cavity 201 and the oil storage tank 301, so that the plunger cavity 201 is connected to the lubrication groove 303.

[0045] When the cylinder block 1 pumps oil, the oil in the plunger hole 101 flows into the plunger chamber 201 via the pressure reducing channel 501. The oil in the plunger chamber 201 increases, and the oil pressure increases, so that the oil in the plunger chamber 201 is sequentially transported to the lubrication groove 303 via the first oil delivery hole 202, the oil storage groove 301, and the second oil delivery hole 302, replenishing the lubrication groove 303 with oil, so that there is a sufficient amount of oil in the lubrication groove 303, thereby maintaining the lubricating oil layer between the sliding shoe 3 and the swash plate 4.

[0046] In a specific embodiment, the oil storage tank 301 is configured as a hemispherical groove, so that when the sliding shoe 3 and the plunger 2 move relative to each other, the first oil delivery hole 202 can always be connected to the oil storage tank 301 (e.g., Figure 5 shown).

[0047] Combine Figure 4 and Figure 5 As shown, a plurality of buffer grooves 304 are provided in the lubrication groove 303, and the buffer grooves 304 are connected to the lubrication groove 303. An elastic diaphragm 31 is provided at the opening of the buffer groove 304. When the oil pressure in the lubrication groove 303 increases, the elastic diaphragm 31 elastically expands into the buffer groove 304 and can store excess oil. When the oil pressure in the lubrication groove 303 decreases, the elastic diaphragm 31 pushes out the stored oil to replenish the oil.

[0048] Thus, when the plunger 2 is in the oil pumping state, the oil in the plunger hole 101 flows into the plunger cavity 201 through the pressure reducing flow channel 501, and the oil in the plunger cavity 201 is sequentially delivered to the lubricating groove 303 through the first oil delivery hole 202, the oil storage groove 301 and the second oil delivery hole 302. At this time, the oil pressure in the lubricating groove 303 increases, the elastic diaphragm 31 elastically expands into the buffer groove 304, and stores excess oil. When the plunger 2 is in the oil pumping state, the oil in the plunger cavity 201 flows into the plunger hole 101 under the action of negative pressure through the pressure reducing flow channel 501, and the oil pressure in the plunger cavity 201 also decreases. Correspondingly, the oil in the lubricating groove 303 is sequentially sucked into the plunger cavity 201 through the second oil delivery hole 302, the oil storage groove 301 and the first oil delivery hole 202. At this time, the elastic diaphragm 31 pushes the stored oil out to supplement the oil in the lubricating groove 303. When the plunger 2 is in the oil pumping or oil pumping state, there is always sufficient oil in the lubricating groove 303 to maintain the lubricating oil layer between the shoe 3 and the swash plate 4.

[0049] In an optional embodiment, the elastic diaphragm 31 is made of nitrile rubber, which has good elasticity and good oil resistance, and can be used in an oil environment for a long time.

[0050] In combination Figure 4 and Figure 5 As shown in the figures, the pressure reducing flow channel 501 is provided as an S-shaped pressure reducing flow channel, which can increase the flow path of the oil, thereby providing good pressure reduction for the oil.

[0051] In an optional embodiment, the material of the plunger core plug 5 and the connecting plate 51 is polypropylene, which has good oil resistance and can be used in an oil environment for a long time.

[0052] In a specific embodiment, the side surface of the connecting plate 51 is provided with external threads, and the opening of the plunger 2 is provided with an internal thread groove. The connecting plate 51 is connected to the plunger 2 by threads, and the plunger core plug 5 is convenient to disassemble, which is conducive to the later maintenance.

[0053] Further, the side end surface of the connecting plate 51 away from the plunger core plug 5 is provided with a wrench insertion slot 504 for connecting with a wrench, and the wrench insertion slot 504 is a regular hexagonal slot, so that a hexagonal wrench can be connected with the wrench insertion slot 504, thereby rotating and disassembling the plunger core plug 5.

[0054] The working principle of the present invention is as follows: an external driving device drives the cylinder body 1 to rotate through the connecting shaft 11. As the cylinder body 1 rotates, under the constraint of the swash plate 4, the plunger 2 can reciprocate in the plunger hole 101 to absorb and pump oil, and the oil is diverted by the distribution plate 12, so that the plunger hole 101 in the oil pumping state and the plunger hole 101 in the oil absorbing state are separated from each other, and the pumping and absorbing oil are concentrated respectively; when the plunger 2 pumps oil, the oil in the plunger hole 101 is decompressed through the decompression channel 501 and flows into the plunger cavity 201, when the plunger 2 absorbs oil, the oil in the plunger cavity 201 flows into the plunger hole 101 through the decompression channel 501 under the action of negative pressure. In the oil absorption state and oil pumping state of the plunger 2, the oil will flow through the decompression channel 501. When the oil flows in the decompression channel 501, it contacts the inner wall of the plunger cavity 201, thereby cooling the plunger 2; at the same time, the decompression channel 501 is used to reduce the pressure inside the plunger cavity 201 when the plunger 2 pumps oil, so as to avoid the expansion of the plunger 2 due to excessive oil pressure. When the plunger 2 is in the oil pumping state, the oil in the plunger hole 101 flows into the plunger cavity 201 through the pressure reducing channel 501, and the oil pressure in the plunger cavity 201 increases, so that the oil in the plunger cavity 201 is sequentially transported to the lubrication groove 303 through the first oil delivery hole 202, the oil storage groove 301 and the second oil delivery hole 302. At this time, the oil pressure in the lubrication groove 303 increases accordingly, and the elastic diaphragm 31 elastically expands into the buffer groove 304 and stores excess oil; when the plunger 2 is in the oil absorbing state, the oil in the plunger cavity 201 is Under the action of negative pressure, the oil flows into the plunger hole 101 through the pressure reducing channel 501, and the oil pressure in the plunger cavity 201 also decreases. Accordingly, the oil in the lubrication groove 303 is sucked into the plunger cavity 201 through the second oil delivery hole 302, the oil storage groove 301 and the first oil delivery hole 202 in sequence. At this time, the elastic diaphragm 31 pushes out the stored oil and replenishes the oil in the lubrication groove 303. When the plunger 2 is in the oil absorbing or pumping state, there is always sufficient oil in the lubrication groove 303 to maintain the lubricating oil layer between the sliding shoe 3 and the swash plate 4.

[0055] In summary of the above embodiments: by arranging a column core plug 5 in the plunger cavity 201 of the plunger 2, and arranging a pressure reducing flow channel 501 on the column core plug 5, when the plunger 2 pumps oil, the oil in the plunger hole 101 is decompressed through the pressure reducing flow channel 501 and flows into the plunger cavity 201; when the plunger 2 absorbs oil, the oil in the plunger cavity 201 flows into the plunger hole 101 through the pressure reducing flow channel 501 under the action of negative pressure; in both the oil absorbing state and the oil pumping state of the plunger 2, the oil will flow through the pressure reducing flow channel 501; when the oil flows in the pressure reducing flow channel 501, it contacts the inner wall of the plunger cavity 201, thereby cooling the plunger 2; at the same time, the pressure reducing flow channel 501 is used to reduce the pressure inside the plunger cavity 201 when the plunger 2 pumps oil, thereby avoiding expansion of the plunger 2 due to excessive oil pressure;

[0056] By providing a buffer groove 304 connected to the lubrication groove 303 on the slipper 3, when the plunger 2 is in the oil pumping state, the oil pressure in the lubrication groove 303 increases, and the elastic diaphragm 31 elastically expands into the buffer groove 304 and stores excess oil. When the plunger 2 is in the oil suction state, the oil pressure in the lubrication groove 303 decreases. At this time, the elastic diaphragm 31 pushes out the stored oil and replenishes the oil into the lubrication groove 303. When the plunger 2 is in the oil suction or oil pumping state, there is always sufficient oil in the lubrication groove 303 to maintain the lubricating oil layer between the slipper 3 and the swash plate 4.

[0057] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0058] The present invention and its embodiments are described above. This description is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. In short, if a person skilled in the art is inspired by this and, without departing from the purpose of the present invention, designs structures and embodiments similar to this technical solution without inventiveness, they shall fall within the scope of protection of the present invention.

Claims

1. A straight-axis swash plate hydraulic plunger pump core, characterized in that: include: A cylinder body (1), wherein a plurality of plunger holes (101) are formed on the cylinder body (1) and are evenly distributed in the circumferential direction, and a swash plate (4) and a return plate (6) are provided at one end of the cylinder body (1); The number of plungers (2) corresponds to the number of the plunger holes (101), one end of the plunger (2) slides in the plunger hole (101), the other end of the plunger (2) is provided with a plunger ball head (21), the plunger ball head (21) is connected to a sliding shoe (3), the sliding shoe (3) is connected to the return plate (6), and is restricted by the return plate (6) between the swash plate (4) and the return plate (6), and under the constraint of the swash plate (4), the cylinder body (1) rotates, so that the plunger (2) can reciprocate in the plunger hole (101) to achieve oil suction or oil pumping; The plunger (2) is provided with a plunger cavity (201) with an opening facing the plunger hole (101), wherein a cylindrical column plug (5) is provided in the plunger cavity (201), and a connecting plate (51) is provided at one end of the column plug (5) for sealing the opening of the plunger cavity (201); The outer wall of the column core plug (5) is provided with a plurality of circumferentially distributed pressure-reducing channels (501), one end of the pressure-reducing channel (501) passes through the connecting plate (51) and is in communication with the plunger hole (101), and the other end of the pressure-reducing channel (501) is in communication with the plunger cavity (201). When the plunger (2) pumps oil, the oil in the plunger hole (101) is decompressed through the pressure-reducing channel (501) and then flows into the plunger cavity (201); A lubrication groove (303) for storing oil is provided on a side of the sliding shoe (3) that contacts the swash plate (4), so that a lubricating oil layer can be formed between the sliding shoe (3) and the swash plate (4) when the sliding shoe (3) and the swash plate (4) rub against each other; An oil storage tank (301) is provided on one side of the sliding shoe (3) connected to the plunger (2), and a second oil delivery hole (302) communicating with the oil storage tank (301) and the lubricating groove (303) is also provided on the sliding shoe (3). A first oil delivery hole (202) communicating with the plunger cavity (201) and the oil storage tank (301) is provided on the plunger (2). When the cylinder body (1) pumps oil, the oil in the plunger cavity (201) can be delivered to the lubricating groove (303); A plurality of buffer grooves (304) are provided in the lubrication groove (303), and an elastic diaphragm (31) is provided at the opening of the buffer groove (304). When the oil pressure in the lubrication groove (303) increases, the elastic diaphragm (31) elastically expands into the buffer groove (304) to store oil. When the oil pressure in the lubrication groove (303) decreases, the elastic diaphragm (31) pushes out the stored oil to replenish the oil.

2. The pump core of the straight-axis swash plate hydraulic plunger pump according to claim 1, characterized in that: The pressure reducing flow channel (501) is configured as an S-shaped pressure reducing flow channel.

3. The pump core of the straight-axis swash plate hydraulic plunger pump according to claim 1, characterized in that: An external thread is provided on the side of the connecting plate (51), and an internal thread is provided at the opening of the plunger (2). The connecting plate (51) is connected to the plunger (2) via the thread.

4. The pump core of the straight-axis swash plate hydraulic plunger pump according to claim 1, characterized in that: A wrench slot (504) for connecting to a wrench is provided on an end surface of the connecting plate (51) away from the column plug (5).

5. The pump core of the straight-axis swash plate hydraulic plunger pump according to claim 1, characterized in that: The connecting plate (51) is provided with first oil holes (502) corresponding in number to the number of the pressure-reducing flow channels (501), and the pressure-reducing flow channels (501) are connected to the plunger hole (101) through the first oil holes (502).

6. The pump core of the straight-axis swash plate hydraulic plunger pump according to claim 1, characterized in that: The end of the column plug (5) away from the connecting plate (51) is provided with second oil holes (503) corresponding in number to the pressure reducing flow channels (501), and the pressure reducing flow channels (501) are communicated with the plunger cavity (201) through the second oil holes (503).

7. The pump core of the straight-axis swash plate hydraulic plunger pump according to claim 1, characterized in that: A distribution plate (12) is provided at one end of the cylinder body (1) away from the swash plate (4).

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