Plunger pump eccentric shaft assembly and plunger pump

Abstract

The present application relates to the technical field of hydraulic transmission equipment, in particular to a plunger pump eccentric shaft assembly and a plunger pump, the plunger pump eccentric shaft assembly comprises a shaft body and a plurality of eccentric discs, the eccentric discs are detachably connected with the shaft body, and the plurality of eccentric discs are arranged at intervals in the axial direction of the shaft body. The plunger pump eccentric shaft assembly can improve the service life of the eccentric shaft and the plunger pump.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydraulic transmission equipment, in particular to a plunger pump eccentric shaft assembly and a plunger pump. BACKGROUND

[0002] The radial plunger pump is named as a kind of plunger pump because the movement direction of the plunger is perpendicular to the rotating shaft, compared with the reciprocating plunger pump and the axial plunger pump, because the plungers are distributed along the radial direction, the number of plungers or the number of plunger rows can be increased to reduce the flow pulsation of the plunger pump as much as possible, and the driving shaft can also reach static balance and dynamic balance. SUMMARY

[0003] The present application is based on the discovery and understanding of the inventors on the following facts and problems:

[0004] The related art discloses a radial plunger pump with water lubrication and valve-combined flow distribution, the radial plunger pump comprises an annular housing, a front end cover and a rear end cover installed at both ends of the annular housing, a rotating eccentric shaft, a plurality of plunger shoe assemblies, a pressure-out flow distribution valve assembly and a flow distribution valve cover plate, the rotating eccentric shaft is coaxially arranged with the annular housing, and a flow distribution groove is formed in the rotating eccentric shaft, the plurality of plunger shoe assemblies are uniformly distributed along the circumference of the rotating eccentric shaft, and the plunger shoe assemblies reciprocate along the radial direction of the annular housing during the rotation of the rotating eccentric shaft. However, the present application inventors found that the radial plunger pump in the related art, although the through hole is arranged in the eccentric part to reduce the weight, still has the dynamic imbalance phenomenon, which causes the eccentric wear of the shoe, and the requirement for the supporting bearings on both sides is also high, which is not conducive to the service life of the whole pump.

[0005] The present application aims to at least solve one of the technical problems in the related art. To this end, the embodiment of the present application proposes a plunger pump eccentric shaft assembly, which can improve the service life of the eccentric shaft and the plunger pump.

[0006] The embodiment of the present application also proposes a plunger pump.

[0007] The plunger pump eccentric shaft assembly of the embodiment of the present application comprises: a shaft body; a plurality of eccentric discs, which are detachably connected with the shaft body, and the plurality of eccentric discs are arranged at intervals in the axial direction of the shaft body.

[0008] The plunger pump eccentric shaft assembly according to the embodiment of the present application can improve the service life of the eccentric shaft and the plunger pump.

[0009] In some embodiments, a plurality of mounting grooves are arranged on the shaft body at intervals in the axial direction of the shaft body, and the eccentric discs are located in the mounting grooves.

[0010] In some embodiments, the eccentric disc includes a first eccentric disc, a second eccentric disc, a third eccentric disc and a fourth eccentric disc arranged in an axial direction of the shaft body, the second eccentric disc and the third eccentric disc are located between the first eccentric disc and the fourth eccentric disc, the first eccentric disc, the second eccentric disc, the third eccentric disc and the fourth eccentric disc are each provided with an oil suction groove, the oil suction grooves of the second eccentric disc and the third eccentric disc are oriented in the same direction, the oil suction grooves of the first eccentric disc and the fourth eccentric disc are oriented in the same direction, and the oil suction groove of the first eccentric disc is oriented in a direction different from the oil suction groove of the second eccentric disc.

[0011] In some embodiments, the oil suction groove has a first end and a second end in a circumferential direction of the eccentric disc, and a flow area of the oil suction groove gradually decreases in a direction from the first end to the second end in the circumferential direction of the eccentric disc.

[0012] In some embodiments, the eccentric disc is a disc, and a line connecting the first end and the center of the eccentric disc and a line connecting the second end and the center of the eccentric disc have an included angle A, and 90°≤A≤180°.

[0013] In some embodiments, the shaft body is provided with a flow channel, the eccentric disc is provided with a through hole, the through hole extends in a radial direction of the shaft body, one end of the through hole is in communication with one end of the flow channel, the other end of the through hole is in communication with the outside, and the other end of the flow channel is adapted to be connected to a hydraulic oil source.

[0014] In some embodiments, the plunger pump input assembly further includes a plurality of adjusting rings, the adjusting rings are sleeved on the shaft body, and the adjusting rings are arranged between adjacent two eccentric discs.

[0015] In some embodiments, the plunger pump input assembly further includes a first retainer ring and a second retainer ring, the first retainer ring and the second retainer ring are respectively sleeved on the shaft body, and a plurality of the eccentric discs are arranged between the first retainer ring and the second retainer ring.

[0016] In some embodiments, the plunger pump input assembly further comprises a first bearing and a second bearing, the first bearing and the second bearing are sleeved on the shaft body respectively, a plurality of the eccentric discs are arranged between the first bearing and the second bearing, the first bearing is oppositely arranged with a first end and a second end in the axial direction of the shaft body, the second bearing is oppositely arranged with a third end and a fourth end in the axial direction of the shaft body, the eccentric disc adjacent to the first bearing among the plurality of the eccentric discs is oppositely arranged with a first side and a second side in the axial direction of the shaft body, the eccentric disc adjacent to the second bearing among the plurality of the eccentric discs is oppositely arranged with a third side and a fourth side in the axial direction of the shaft body, the distance between the first end and the first side in the axial direction of the shaft body is B, the distance between the third end and the third side in the axial direction of the shaft body is C, and B=C.

[0017] The plunger pump of the embodiment of the present application comprises: a pump body; an eccentric shaft assembly arranged in the pump body and rotatable relative to the pump body, the eccentric shaft assembly being the eccentric shaft assembly of any one of the above embodiments.

[0018] The plunger pump according to the embodiment of the present application can improve the service life of the plunger pump. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 FIG. 1 is a structural schematic diagram of the eccentric shaft assembly of the plunger pump of the embodiment of the present application.

[0020] Figure 2 FIG. 2 is a sectional view of the eccentric shaft assembly of the plunger pump of the embodiment of the present application.

[0021] Figure 3 FIG. 3 is a sectional view of the eccentric disc of the embodiment of the present application.

[0022] Figure 4 FIG. 4 is a sectional view of the shaft body of the embodiment of the present application.

[0023] Figure 5 FIG. 5 is a perspective view of the eccentric disc of the embodiment of the present application.

[0024] REFERENCE SIGNS:

[0025] shaft body 1, mounting groove 11,

[0026] eccentric disc 2, first eccentric disc 21, second eccentric disc 22, third eccentric disc 23, fourth eccentric disc 24, oil suction groove 201, first end 2011, second end 2022, through hole 25,

[0027] adjusting ring 3, first retainer 4, second retainer 5, first bearing 6, second bearing 7. DETAILED DESCRIPTION

[0028] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0029] The plunger pump eccentric shaft assembly of this invention includes a shaft 1 and a plurality of eccentric discs 2.

[0030] The eccentric disk 2 is detachably connected to the shaft 1, and multiple eccentric disks 2 are axially connected to the shaft 1 (e.g., ...). Figure 1 The left and right directions are arranged at intervals as shown.

[0031] like Figure 1 and Figure 3 As shown, the eccentric disk 2 has a mounting hole in the middle and a keyway on it. One end of the keyway is connected to the mounting hole. The shaft 1 passes through the mounting hole and is connected to the eccentric disk 2 by a key. The key is located in the keyway.

[0032] For example, the eccentric disk 2 is made of wear-resistant material.

[0033] According to an embodiment of the present invention, the eccentric disc 2 of the plunger pump eccentric shaft assembly is detachably connected to the shaft body 1. The eccentric disc 2 can be individually treated for wear resistance or made of wear-resistant material. Compared with the input shaft being an integral structure, this reduces the manufacturing cost of the eccentric shaft assembly. Furthermore, when the eccentric shaft wears down, only the worn eccentric disc 2 needs to be replaced, without replacing the entire eccentric shaft assembly, thereby improving the service life of the eccentric shaft and the plunger pump.

[0034] In some embodiments, the shaft 1 is provided with a plurality of mounting grooves 11, which are arranged at intervals along the axial direction of the shaft 1, and the eccentric disk 2 is located in the mounting groove 11.

[0035] Specifically, such as Figure 4 As shown, the mounting groove 11 extends radially upward along the shaft 1. The dimension of the mounting groove 11 in the left-right direction is approximately equal to the dimension of the eccentric disk 2 in the left-right direction. When the eccentric disk 2 is installed into the mounting groove 11, the sidewall of the mounting groove 11 contacts the left and right end faces of the eccentric disk 2.

[0036] For example, a flat key or a pin can be installed in the mounting slot 11. The shape and structure of the mounting slot are adapted to the shape and structure of the flat key or the pin. The eccentric disk 2 is fixed in the circumferential direction by the flat key, pin or other structure to prevent the eccentric disk from rotating.

[0037] In some embodiments, the eccentric disc 2 comprises a first eccentric disc 21, a second eccentric disc 22, a third eccentric disc 23 and a fourth eccentric disc 24 arranged in an axial direction of the shaft body 1, the second eccentric disc 22 and the third eccentric disc 23 are located between the first eccentric disc 21 and the fourth eccentric disc 24, the first eccentric disc 21, the second eccentric disc 22, the third eccentric disc 23 and the fourth eccentric disc 24 are all provided with oil suction grooves 21, the oil suction grooves 21 of the second eccentric disc 22 and the third eccentric disc 23 are in the same direction, the oil suction grooves 21 of the first eccentric disc 21 and the fourth eccentric disc 24 are in the same direction, and the direction of the oil suction grooves 21 of the first eccentric disc 21 is different from that of the second eccentric disc 22.

[0038] Specifically, as shown in Figure 1 and Figure 2 , the first eccentric disc 21, the second eccentric disc 22, the third eccentric disc 23 and the fourth eccentric disc 24 are uniformly spaced from left to right, and the sizes and shapes of the first eccentric disc 21, the second eccentric disc 22, the third eccentric disc 23 and the fourth eccentric disc 24 are the same. The first eccentric disc 21 and the fourth eccentric disc 24 are symmetrically arranged in the left-right direction, the second eccentric disc 22 and the third eccentric disc 23 are symmetrically arranged in the left-right direction, the first eccentric disc 21, the second eccentric disc 22, the third eccentric disc 23 and the fourth eccentric disc 24 are all provided with oil suction grooves 21 of the same size and shape, the oil suction grooves 21 of the first eccentric disc 21 and the fourth eccentric disc 24 are in the same direction, the oil suction grooves 21 of the second eccentric disc 22 and the third eccentric disc 23 are in the same direction, and the direction of the oil suction grooves 21 of the first eccentric disc 21 and the fourth eccentric disc 24 is different from that of the second eccentric disc 22 and the third eccentric disc 23, so that

[0039] For example, the direction of the oil suction grooves 21 of the first eccentric disc 21 and the fourth eccentric disc 24 and the direction of the oil suction grooves 21 of the second eccentric disc 22 and the third eccentric disc 23 are matched with the position of the mounting groove 11 corresponding to the eccentric disc 2.

[0040] The plunger pump eccentric shaft assembly of the embodiment of the application, by arranging four eccentric discs 2, and symmetrically arranging the four eccentric discs 2 in the left-right direction, the second eccentric disc 22 and the third eccentric disc 23 located in the middle have the same direction of the oil suction grooves 21 and different from the direction of the oil suction grooves 21 of the first eccentric disc 21 and the fourth eccentric disc 24 located on both sides, when the eccentric shaft assembly rotates, the eccentric shaft realizes dynamic balance, and the stability of the operation of the eccentric shaft assembly and the precision and stability of the operation of the plunger pump are improved.

[0041] It should be noted that when the number of eccentric discs 2 is greater than or less than four, the eccentric shaft generates a torque in the circumferential direction, which causes the eccentric shaft assembly to be unable to realize dynamic balance, thereby being not conducive to the operation of the eccentric shaft and the plunger pump.

[0042] In some embodiments, the oil suction groove 21 has a first end 2011 (as shown in Figure 3 the lower end of the oil suction groove 21) and a second end 2022 (as shown in Figure 3 the upper end of the oil suction groove 21) in the circumferential direction of the eccentric disc 2, and the flow cross-sectional area of the oil suction groove 21 gradually decreases in the direction from the first end 2011 to the second end 2022 in the circumferential direction of the eccentric disc 2.

[0043] It should be noted that the lower end of the oil suction groove 21 is the initial end of liquid suction, and the upper end of the oil suction groove 21 is the terminal end of liquid suction.

[0044] Specifically, as shown in Figure 3 , the oil suction groove 21 extends along the circumferential direction of the eccentric disc 2, and the oil suction groove 21 is an arc-shaped groove, the flow cross-sectional area of the oil suction groove 21 gradually decreases from the initial end to the terminal end in the circumferential direction of the eccentric disc 2, and the inner side of the initial end of the oil suction groove 21 is an inwardly recessed arc-shaped surface, thereby increasing the volume of the initial end of liquid suction.

[0045] The eccentric shaft assembly of the plunger pump of the embodiment of the present application, by arranging the arc-shaped oil suction groove 21, makes the liquid flow more stable in the oil suction groove 21, the flow cross-sectional area of the initial end of the oil suction groove 21 is greater than that of the terminal end of the oil suction groove 21, and the flow cross-sectional area of the oil suction groove 21 gradually decreases from the initial end to the terminal end, when the plunger sucks liquid, because the initial speed of the plunger is fast when the plunger just sucks liquid, the liquid suction speed is fast, the volume of the initial end of liquid suction is increased, which is convenient for the plunger to suck liquid, the terminal speed of the plunger is low, and the volume of the terminal end of liquid suction is small, thereby improving the precision and stability of the plunger operation.

[0046] In some embodiments, the eccentric disc is a circular disc, and the line connecting the first end 2011 and the center of the eccentric disc 2 and the line connecting the second end 2022 and the center of the eccentric disc 2 have an included angle A, and 90°≤A≤180°.

[0047] Specifically, as shown in Figure 3 , the included angle between the line connecting the initial end of the oil suction groove 21 and the center of the eccentric disc 2 and the line connecting the terminal end of the oil suction groove 21 and the center of the eccentric disc 2 is A, and A=90°, 110°, 120°, 135°, 145°, 155°, 160°, 170°, 180°.

[0048] It should be noted that the size of the included angle A is determined by the size of the sliding shoe in the plunger pump, that is, the larger the sliding shoe, the larger the angle of the included angle A, and vice versa, the smaller the sliding shoe, the smaller the angle of the included angle A.

[0049] In some embodiments, the shaft body 1 is provided with a flow channel, the eccentric disc 2 is provided with a through hole 25 extending along the radial direction of the shaft body 1, one end of the through hole 25 is communicated with one end of the flow channel, and the other end of the through hole 25 is communicated with the outside world, and the other end of the flow channel is adapted to be connected with a hydraulic oil source.

[0050] For example, one end of the flow channel is communicated with the outside world, and the other end of the flow channel communicated with the outside world can be externally connected with a gear pump, the gear pump delivers hydraulic oil or lubricating oil to the eccentric disc 2 through the flow channel, the other end of the flow channel is communicated with the through hole 25 on the eccentric disc 2, the through hole 25 extends along the radial direction of the shaft body 1, and the through hole 25 is communicated with the outer circumferential surface of the eccentric disc 2, the hydraulic oil or lubricating oil in the flow channel flows to the outer circumferential surface of the eccentric disc 2 through the through hole 25, and when the shoe is corresponding to the eccentric disc 2, the lubricating oil or hydraulic oil forms an oil film between the eccentric disc 2 and the shoe, avoiding direct contact between the shoe and the eccentric disc 2, reducing the wear of the shoe and the eccentric disc 2, and improving the service life of the shoe and the eccentric disc 2.

[0051] In some embodiments, the plunger pump input assembly further comprises a plurality of adjusting rings 3, the adjusting rings 3 are sleeved on the shaft body 1, and the adjusting rings 3 are arranged between adjacent two eccentric discs 2.

[0052] Specifically, as shown in the figure, Figure 2 one adjusting ring 3 is arranged between adjacent two eccentric discs 2, the left end surface of the adjusting ring 3 is in contact with the right end surface of one of the two eccentric discs 2, and the right end surface of the adjusting ring 3 is in contact with the left end surface of the other eccentric disc 2, and the positions of the adjacent two eccentric discs 2 in the left-right direction are adjusted by arranging the adjusting ring 3.

[0053] The plunger pump eccentric shaft assembly of the embodiment of the application can axially position the eccentric disc 2 through the adjusting ring 3, avoid axial displacement of the eccentric disc 2, and also realize dynamic balance of the eccentric shaft assembly, thereby improving the operation precision and stability of the plunger pump.

[0054] In some embodiments, the plunger pump input assembly further comprises a first retainer ring 4 and a second retainer ring 5, the first retainer ring 4 and the second retainer ring 5 are respectively sleeved on the shaft body 1, and the plurality of eccentric discs 2 are arranged between the first retainer ring 4 and the second retainer ring 5.

[0055] Specifically, as shown in the figure, Figure 2 the first retainer ring 4 and the second retainer ring 5 are arranged in the left-right direction, the right end surface of the first retainer ring 4 is in contact with the left end surface of the leftmost one of the eccentric discs 2, and the left end surface of the second retainer ring 5 is in contact with the right end surface of the rightmost one of the eccentric discs 2. By arranging the first retainer ring 4 and the second retainer ring 5, the eccentric disc 2 can be axially positioned to avoid movement of the eccentric disc 2 in the left-right direction, thereby improving the stability and assembly precision of the operation of the eccentric shaft assembly.

[0056] In some embodiments, the plunger pump input assembly further comprises a first bearing 6 and a second bearing 7, the first bearing 6 and the second bearing 7 are sleeved on the shaft body 1 respectively, a plurality of eccentric discs 2 are arranged between the first bearing 6 and the second bearing 7, the first bearing 6 is oppositely arranged with a first end 2011 and a second end 2022 in the axial direction of the shaft body 1, the second bearing 7 is oppositely arranged with a third end and a fourth end in the axial direction of the shaft body 1, an eccentric disc 2 adjacent to the first bearing 6 in the plurality of eccentric discs 2 is oppositely arranged with a first side and a second side in the axial direction of the shaft body 1, an eccentric disc 2 adjacent to the second bearing 7 in the plurality of eccentric discs 2 is oppositely arranged with a third side and a fourth side in the axial direction of the shaft body 1, the distance between the first end 2011 and the first side in the axial direction of the shaft body 1 is B, the distance between the third end and the third side in the axial direction of the shaft body 1 is C, and B=C.

[0057] Specifically, as shown in Figure 1 and Figure 2 , the first bearing 6 and the second bearing 7 are arranged in the left-right direction, the plurality of eccentric discs 2, the adjusting ring 3, the first retainer ring 4 and the second retainer ring 5 are arranged between the first bearing 6 and the second bearing 7, the distance between the right end face of the first bearing 6 and the left end face of the leftmost eccentric disc 2 in the left-right direction is B, the distance between the left end face of the second bearing 7 and the right end face of the rightmost eccentric disc 2 in the left-right direction is C, and B=C.

[0058] The plunger pump eccentric shaft assembly of the embodiment of the present application can support the eccentric shaft assembly by arranging the first bearing 6 and the second bearing 7, the distance between the right end face of the first bearing 6 and the left end face of the leftmost eccentric disc 2 in the left-right direction is B, the distance between the left end face of the second bearing 7 and the right end face of the rightmost eccentric disc 2 in the left-right direction is C, and B=C, when the eccentric shaft rotates, the symmetrically arranged first bearing 6 and second bearing 7 ensure that the eccentric shaft realizes dynamic balance, thereby improving the stability of the rotation of the eccentric shaft assembly and the precision of the operation of the plunger pump.

[0059] The plunger pump of the embodiment of the present application comprises a pump body and an eccentric shaft assembly.

[0060] The eccentric shaft assembly is arranged in the pump body, and the eccentric shaft assembly is rotatable relative to the pump body, and the eccentric shaft assembly is the eccentric shaft assembly of any one of the above embodiments.

[0061] The plunger pump according to the embodiment of the present application adopts the above-mentioned eccentric shaft assembly, the eccentric disc 2 is detachably connected with the shaft body 1, the eccentric disc 2 can be individually subjected to wear-resistant treatment or the eccentric disc 2 is made of wear-resistant material, compared with the integrated structure of the input shaft, the manufacturing cost of the eccentric shaft assembly is reduced, and when the eccentric shaft is worn, only the worn eccentric disc 2 needs to be replaced, without the need to replace the entire eccentric shaft assembly, thereby improving the service life of the eccentric shaft and the plunger pump.

[0062] In the description of the present application, it is to be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the devices or elements indicated thereby must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0063] In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated thereby. Therefore, the features defined with "first", "second", etc. can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise explicitly specified and limited.

[0064] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected or in communication with each other; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication or interaction relationship of two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0065] In the present application, unless otherwise explicitly specified and limited, the first feature "on" or "under" the second feature can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature "above", "over" and "on" the second feature can be that the first feature is directly above or obliquely above the second feature, or it can only mean that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "under" and "under" the second feature can be that the first feature is directly below or obliquely below the second feature, or it can only mean that the horizontal height of the first feature is less than that of the second feature.

[0066] In this disclosure, the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" mean that a particular feature, structure, material, or characteristic is included in at least one embodiment or example of the present disclosure. The illustrative appearances of the above-mentioned terms in various places in the specification are not necessarily referred to the same embodiment or example. Moreover, the particular features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples. Furthermore, the terminology "comprising" is used in the disclosure as comprising but not limited to, that is, it is open-ended and does not exclude the presence of additional features, structures, materials, or characteristics.

[0067] Although the embodiments of the present disclosure have been shown and described above, it is understood that the above-described embodiments are exemplary, and are not to be interpreted as limiting the present disclosure, and the ordinary skilled person in the art can make changes, modifications, replacements, and variations to the above-described embodiments within the scope of the present disclosure.

Claims

1. A plunger pump eccentric shaft assembly characterized by, Comprise: a shaft body; a plurality of eccentric discs, which are detachably connected with the shaft body, and the plurality of eccentric discs are arranged in the axial direction of the shaft body; the eccentric discs comprise a first eccentric disc, a second eccentric disc, a third eccentric disc and a fourth eccentric disc arranged in the axial direction of the shaft body, the second eccentric disc and the third eccentric disc are located between the first eccentric disc and the fourth eccentric disc, the first eccentric disc, the second eccentric disc, the third eccentric disc and the fourth eccentric disc are all provided with oil suction grooves, the oil suction grooves of the second eccentric disc and the third eccentric disc are in the same direction, the oil suction grooves of the first eccentric disc and the fourth eccentric disc are in the same direction, and the direction of the oil suction groove of the first eccentric disc is different from that of the second eccentric disc; the oil suction groove has a first end and a second end in the circumferential direction of the eccentric disc, and the flow area of the oil suction groove gradually decreases from the first end to the second end in the circumferential direction of the eccentric disc; the shaft body is provided with a flow channel, the eccentric disc is provided with a through hole, the through hole extends in the radial direction of the shaft body, one end of the through hole is communicated with one end of the flow channel, the other end of the through hole is communicated with the outside, and the other end of the flow channel is adapted to connect a hydraulic oil source.

2. The plunger pump eccentric shaft assembly of claim 1, wherein, a plurality of mounting grooves are arranged on the shaft body in the axial direction of the shaft body, and the eccentric discs are located in the mounting grooves.

3. The plunger pump eccentric shaft assembly of claim 1, wherein, The eccentric disc is a disc, and the line connecting the first end and the center of the eccentric disc has an included angle A with the line connecting the second end and the center of the eccentric disc, and 90°≤A≤180°.

4. The plunger pump eccentric shaft assembly of any one of claims 1-3, wherein, Further comprising a plurality of adjusting rings, the adjusting rings are sleeved on the shaft body, and the adjusting rings are arranged between adjacent two eccentric discs.

5. The plunger pump eccentric shaft assembly of any one of claims 1-3, wherein, Further comprising a first retainer ring and a second retainer ring, the first retainer ring and the second retainer ring are respectively sleeved on the shaft body, and a plurality of eccentric discs are arranged between the first retainer ring and the second retainer ring.

6. The plunger pump eccentric shaft assembly of claim 5, wherein, Further comprising a first bearing and a second bearing, the first bearing and the second bearing are respectively sleeved on the shaft body, a plurality of eccentric discs are arranged between the first bearing and the second bearing, the first bearing is relatively arranged with a first end and a second end in the axial direction of the shaft body, the second bearing is relatively arranged with a third end and a fourth end in the axial direction of the shaft body, the eccentric disc adjacent to the first bearing among the plurality of eccentric discs is relatively arranged with a first side and a second side in the axial direction of the shaft body, the eccentric disc adjacent to the second bearing among the plurality of eccentric discs is relatively arranged with a third side and a fourth side in the axial direction of the shaft body, the distance between the first end and the first side in the axial direction of the shaft body is B, the distance between the third end and the third side in the axial direction of the shaft body is C, and B=C.

7. A piston pump characterized in that Comprise: a pump body; an eccentric shaft assembly, which is arranged in the pump body and is rotatable relative to the pump body, and the eccentric shaft assembly is as claimed in any one of claims 1-6.

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