Plunger assembly and plunger pump

Abstract

The present invention relates to the technical field of plunger pumps, and in particular, to a plunger assembly and a plunger pump. The plunger assembly comprises a cylinder unit, a plunger unit and a slipper unit. The plunger unit is slidably inserted in the cylinder unit; a plunger cavity is formed between the end of the plunger rod of the plunger unit away from the plunger ball head and the cylinder unit; a weight reduction cavity in the plunger rod passes through to the end of the plunger rod away from the plunger ball head; a partition in the weight reduction cavity divides the weight reduction cavity into a buffer cavity and a connecting cavity; the connecting cavity is connected to the plunger cavity; the oil through hole in the plunger ball head is connected to the connecting cavity; a first shock-absorbing hole formed at one end of the partition near the plunger cavity is respectively connected to the buffer cavity and the plunger cavity; a second shock-absorbing hole at one end of the partition near the plunger ball head is respectively connected to the buffer cavity and the oil through hole; the slipper unit is spherically hinged with the plunger ball head; one end of the oil through hole passes through to the surface where the plunger ball head and the slipper unit fit. In this way, the problem of how to reduce pressure pulsation in the plunger assembly is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of plunger pumps, and in particular to a plunger assembly and a plunger pump. Background Art

[0002] With the development of hydraulic technology, the requirements for lightweight, low pressure pulsation and durability in the aerospace field are becoming more and more stringent, requiring plunger pumps to develop in the direction of light weight, low pressure pulsation and high durability. The plunger assembly of the plunger pump is the core component of the flow and pressure output components of the plunger pump, which is crucial to the pressure pulsation characteristics and durability of the plunger pump. The pressure pulsation of the plunger pump refers to the phenomenon that during the operation of the plunger pump, its output pressure is not stable, but fluctuates around a certain average value. This is because the plunger pump achieves oil suction and oil pressure through the reciprocating motion of the plunger in the cylinder. When the plunger moves forward (oil pressure), the liquid is forced to be discharged and the pressure increases; when the plunger moves backward (oil suction), the liquid enters the cylinder and the pressure decreases. This periodic movement leads to discontinuity in fluid delivery, resulting in pressure changes. If the pressure pulsation of the plunger pump is large, it will cause vibration and noise, affecting the performance of the plunger pump and the service life of its internal components.

[0003] In order to reduce weight, the plunger assembly of traditional plunger pumps usually adopts the form of vacuum plungers, which has limited pressure pulsation suppression effect and fails to fully utilize the dead space volume of the vacuum plunger, making it difficult to meet the increasingly stringent low pressure pulsation and high durability requirements of plunger pumps in the aerospace field. Installing buffer devices around the plunger assembly, such as accumulators or elastic elements, has a general effect on suppressing pressure pulsation and does not meet the requirements of lightweight plunger pumps. Summary of the invention

[0004] In order to solve the problem of how to reduce pressure pulsation of a plunger assembly, the present invention provides a plunger assembly and a plunger pump.

[0005] In a first aspect, the present invention provides a plunger assembly, the plunger assembly comprising:

[0006] Cylinder unit;

[0007] The plunger unit comprises a plunger rod, a plunger ball head and a partition; the plunger ball head is integrally formed with one end of the plunger rod; the end of the plunger rod away from the plunger ball head is slidably inserted in the cylinder unit; a plunger cavity is formed between the end of the plunger rod away from the plunger ball head and the cylinder unit; a weight-reducing cavity is provided inside the plunger rod; the weight-reducing cavity passes through to the end of the plunger rod away from the plunger ball head; the partition is located in the weight-reducing cavity; the partition is fixedly connected to the plunger rod The partition part is connected or detachably connected; the partition part divides the weight-reducing cavity into a buffer cavity and a communicating cavity; the communicating cavity is communicated with the plunger cavity; the interior of the plunger ball head is provided with an oil through hole; the oil through hole is communicated with the communicating cavity; a first shock-absorbing hole is formed at one end of the partition part close to the plunger cavity; the first shock-absorbing hole is communicated with the buffer cavity and the plunger cavity respectively; a second shock-absorbing hole is formed at one end of the partition part close to the plunger ball head; the second shock-absorbing hole is communicated with the buffer cavity and the oil through hole respectively;

[0008] A slipper unit is spherically hinged with the plunger ball head; one end of the oil through hole passes through to the surface where the plunger ball head and the slipper unit are in contact.

[0009] In some embodiments, the partition portion includes an annular cover plate and a conducting tube; the annular cover plate is fixedly connected to the plunger rod; the annular cover plate is located at the end of the plunger rod away from the plunger ball head; the conducting tube is located in the weight reduction cavity; the conducting tube is detachably connected to the plunger rod and the annular cover plate respectively; the end of the conducting tube close to the annular cover plate is connected to the plunger cavity; the conducting tube, the inner wall of the weight reduction cavity and the annular cover plate form the buffer cavity; the first shock-absorbing hole is opened on the annular cover plate; the second shock-absorbing hole is opened at the end of the conducting tube close to the plunger ball head.

[0010] In some embodiments, a plurality of first shock-absorbing holes are evenly arranged at circumferential intervals along the annular cover plate; a plurality of second shock-absorbing holes are evenly arranged at circumferential intervals along the guiding tube; an axis of the first shock-absorbing hole intersects with an axis of the plunger rod; a plurality of the first shock-absorbing holes are dispersed near one end of the plunger cavity; and a plurality of the first shock-absorbing holes are close to one end of the buffer cavity.

[0011] In some embodiments, a diameter of one end of the first shock absorbing hole close to the plunger cavity is larger than a diameter of one end of the first shock absorbing hole close to the buffer cavity.

[0012] In some embodiments, the sum of cross-sectional areas of the first plurality of shock-absorbing holes is greater than the sum of cross-sectional areas of the second plurality of shock-absorbing holes.

[0013] In some embodiments, a third shock-absorbing hole is opened at one end of the conducting tube close to the annular cover plate; a plurality of the third shock-absorbing holes are evenly arranged at intervals along the circumference of the conducting tube; and the third shock-absorbing holes are respectively connected to the buffer cavity and the connecting cavity.

[0014] In some embodiments, a separator ring is sleeved on the conducting tube; the separator ring separates the buffer chamber into a first chamber and a second chamber; the first chamber is connected to the plunger chamber through the first shock-absorbing hole; the second chamber is connected to the oil hole through the second shock-absorbing hole.

[0015] In some embodiments, the volume of the first cavity is greater than the volume of the second cavity.

[0016] In some embodiments, the separation ring is provided with supply holes; the supply holes are arranged at intervals along the circumference of the separation ring; and the supply holes are connected to the first cavity and the second cavity respectively.

[0017] In a second aspect, the present invention provides a plunger pump, the plunger pump comprising a plunger assembly as described in any one of the above embodiments; the plunger pump further comprises:

[0018] A housing assembly, wherein a chamber is formed inside the housing assembly; the plunger assembly is disposed in the internal chamber of the housing assembly;

[0019] A transmission assembly is driven and connected to the plunger assembly through the housing assembly.

[0020] In order to solve the problem of how to reduce pressure pulsation of the plunger assembly, the present invention has the following advantages:

[0021] By setting a partition in the plunger rod, the weight-reducing chamber in the plunger rod is divided into a buffer chamber and a connecting chamber. The first damping hole is close to the plunger chamber, and the second damping hole is close to the oil through hole. When the plunger assembly is in the oil absorption state, the oil in the plunger chamber flows into the buffer chamber and the connecting chamber respectively. When the plunger assembly is in the oil discharge state, the oil in the connecting chamber flows into the plunger chamber. Part of the oil in the buffer chamber flows into the oil through hole through the second damping hole to the surface where the slipper unit and the plunger ball head are attached, and the other part of the oil flows into the plunger chamber through the first damping hole, so that the buffer chamber can play a role in oil compensation. While meeting the lightweight requirements, the pressure change of the oil flow between the plunger chamber and the connecting chamber is balanced through the first damping hole, and the pressure change of the oil flow between the surface where the slipper unit and the plunger ball head are attached and the connecting chamber is balanced through the second damping hole, thereby reducing the pressure pulsation generated during the oil absorption or oil discharge process of the plunger assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic diagram of a plunger pump according to an embodiment is shown;

[0023] Figure 2 A schematic diagram of a plunger assembly according to an embodiment is shown;

[0024] Figure 3 A schematic diagram of a plunger assembly of another embodiment is shown;

[0025] Figure 4 A schematic diagram of a plunger assembly of another embodiment is shown;

[0026] Figure 5 A schematic diagram of a plunger assembly according to yet another embodiment is shown.

[0027] Figure numerals: 10 housing assembly; 20 transmission assembly; 30 plunger assembly; 31 cylinder unit; 32 plunger unit; 321 plunger rod; 322 weight reduction chamber; 323 plunger ball head; 324 oil hole; 325 partition; 3251 annular cover plate; 3252 first shock-absorbing hole; 3253 guide pipe; 3254 second shock-absorbing hole; 3255 third shock-absorbing hole; 3256 partition ring; 3257 supply hole; 326 plunger chamber; 33 slipper unit; 40 swash plate assembly; 50 distribution plate assembly. DETAILED DESCRIPTION

[0028] The present disclosure will now be discussed with reference to several exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and thus implement the present disclosure, rather than implying any limitation on the scope of the present disclosure.

[0029] As used herein, the term "including" and its variants are to be interpreted as open-ended terms meaning "including but not limited to". The term "based on" is to be interpreted as "based at least in part on". The terms "one embodiment" and "an embodiment" are to be interpreted as "at least one embodiment". The term "another embodiment" is to be interpreted as "at least one other embodiment". The orientation or position relationship indicated by the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "vertical", "horizontal", "lateral", "longitudinal" and the like is based on the orientation or position relationship shown in the accompanying drawings. These terms are mainly for better describing the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation. In addition, in addition to being used to indicate an orientation or position relationship, some of the above terms may also be used to indicate other meanings, such as the term "upper" may also be used to indicate a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to the specific circumstances. In addition, the terms "install", "set", "provided with", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure. It can be a mechanical connection or an electrical connection. It can be directly connected, or indirectly connected through an intermediate medium, or it can be an internal connection between two devices, elements or components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances. In addition, the terms "first", "second", etc. are mainly used to distinguish different devices, elements or components (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance and quantity of the indicated devices, elements or components. Unless otherwise specified, "multiple" means two or more.

[0030] In this embodiment, after the plunger assembly 30 is installed to the plunger pump, the plunger unit 32 can realize the operation of sucking and discharging oil by reciprocating in the cylinder unit 31. Generally speaking, the pulsation at the high-pressure outlet of the plunger pump is larger than the pulsation at the low-pressure inlet. During the operation of the plunger pump, the low-pressure inlet mainly performs the oil suction operation. When the plunger unit 32 extends outward, the volume of the plunger cavity 326 increases, a local vacuum is generated, and the oil is sucked into the plunger cavity 326 under the action of atmospheric pressure. This process is relatively stable and the pressure pulsation is small. At the high-pressure outlet, when the plunger unit 32 retracts inward, the volume of the plunger cavity 326 decreases, and the oil is compressed and discharged. Since the oil needs to be pressurized to a higher pressure to meet the working requirements of the system, and the reciprocating motion of the plunger unit 32 is periodic, this leads to a large pressure change in the oil discharge process, which is easy to generate vibration and noise, and the end of the plunger unit 32 is easily damaged by a large impact, affecting the service life of the plunger pump. To this end, this embodiment discloses a plunger assembly 30.

[0031] like Figure 1 As shown, the plunger assembly 30 may include a cylinder unit 31, a plunger unit 32, and a sliding shoe unit 33. The plunger unit 32 includes a plunger rod 321, a plunger ball head 323, and a partition 325. The plunger ball head 323 is integrally formed with one end of the plunger rod 321. The end of the plunger rod 321 away from the plunger ball head 323 is slidably inserted into the cylinder unit 31. A plunger cavity 326 is formed between the end of the plunger rod 321 away from the plunger ball head 323 and the cylinder unit 31. A weight-reducing cavity 322 is provided inside the plunger rod 321. The weight-reducing cavity 322 passes through the end of the plunger rod 321 away from the plunger ball head 323 to meet the lightweight requirement. The partition 325 is located in the weight-reducing cavity 322. As shown Figure 2 As shown, the partition 325 is fixedly connected or detachably connected to the plunger rod 321, such as welding, threaded connection or interference fit. The partition 325 divides the weight reduction chamber 322 into a buffer chamber and a connecting chamber, and the structural form of the partition 325 is not specifically limited here. The connecting chamber is connected to the plunger chamber 326. The interior of the plunger ball head 323 has an oil through hole 324. The oil through hole 324 is connected to the connecting chamber. A first shock-absorbing hole 3252 is formed at one end of the partition 325 close to the plunger chamber 326. The first shock-absorbing hole 3252 is respectively connected to the buffer chamber and the plunger chamber 326. A second shock-absorbing hole 3254 is formed at one end of the partition 325 close to the plunger ball head 323. The second shock-absorbing hole 3254 is respectively connected to the buffer chamber and the oil through hole 324. The slipper unit 33 is ball-jointed with the plunger ball head 323. One end of the oil hole 324 passes through to the surface where the plunger ball head 323 and the shoe unit 33 are in contact.

[0032] The first damping hole 3252 provides buffer oil supply or oil absorption for the plunger cavity 326. When the plunger rod 321 slides in a direction away from the plunger cavity 326, part of the oil in the buffer cavity can flow into the plunger cavity 326 for pressure compensation. When the plunger rod 321 slides in a direction close to the plunger cavity 326, part of the oil in the plunger cavity 326 can flow into the buffer cavity for pressure release. Thus, the pressure pulsation caused by the volume change of the plunger cavity 326 can be reduced by the buffer cavity, and the damage caused by the vibration of the plunger rod 321 during use can be reduced. The pressure pulsation generated at the fitting surface of the slipper unit 33 and the plunger ball head 323 can be reduced by the buffer cavity and the second damping hole 3254. When the plunger rod 321 slides in a direction away from the plunger cavity 326, part of the oil in the buffer cavity can flow into the oil through hole 324 for lubrication compensation to ensure smooth cooperation between the slipper unit 33 and the plunger ball head 323. When the plunger rod 321 slides toward the plunger cavity 326, part of the oil in the oil hole 324 can flow into the buffer cavity, thereby preventing excessive oil from leaking from the surface where the sliding shoe unit 33 and the plunger ball head 323 meet. This reduces the damage to the plunger ball head 323 caused by vibration or friction during use, further extending the service life of the plunger assembly 30.

[0033] In this embodiment, if Figure 2 As shown, the partition 325 includes an annular cover plate 3251 and a conducting tube 3253. The annular cover plate 3251 is fixedly connected to the plunger rod 321. The annular cover plate 3251 is located at one end of the plunger rod 321 away from the plunger ball head 323. The conducting tube 3253 is located in the weight reduction chamber 322. The conducting tube 3253 is detachably connected to the plunger rod 321 and the annular cover plate 3251 respectively. One end of the conducting tube 3253 close to the annular cover plate 3251 is connected to the plunger chamber 326. The conducting tube 3253, the inner wall of the weight reduction chamber 322 and the annular cover plate 3251 form a buffer chamber. A first shock-absorbing hole 3252 is provided on the annular cover plate 3251. A second shock-absorbing hole 3254 is provided at one end of the conducting tube 3253 close to the plunger ball head 323. The use of the annular cover plate 3251 and the conducting tube 3253 facilitates the processing and installation of the partition 325, and also facilitates the later maintenance and replacement of the partition 325. The first damping hole 3252 and the second damping hole 3254 may also be blocked by oil accumulation after long-term use. The above arrangement can facilitate the cleaning of the first damping hole 3252 and the second damping hole 3254, ensuring that the buffer cavity can fully play the role of alleviating the pressure pulsation generated when the plunger unit 32 is working.

[0034] In this embodiment, if Figure 2As shown, a plurality of first damping holes 3252 are evenly arranged at intervals along the circumference of the annular cover plate 3251. A plurality of second damping holes 3254 are evenly arranged at intervals along the circumference of the conducting tube 3253. Thus, the effect of reducing pressure pulsation by the first damping holes 3252 and the second damping holes 3254 can be improved, and at the same time, the consistency of force on the plunger unit 32 can be ensured. Figure 4 As shown, the axis of the first damping hole 3252 intersects with the axis of the plunger rod 321. Multiple first damping holes 3252 are dispersed near one end of the plunger cavity 326. Multiple first damping holes 3252 are close to one end of the buffer cavity. By setting the first damping holes 3252 in an inclined state, the oil in the buffer cavity is in a divergent state when flowing to the plunger cavity 326 through the first damping holes 3252, further reducing the impact of pressure pulsation on the inner wall of the plunger cavity 326, and improving the damping effect.

[0035] In this embodiment, if Figure 5 As shown, the diameter of the end of the first damping hole 3252 close to the plunger cavity 326 is larger than the diameter of the end of the first damping hole 3252 close to the buffer cavity. The diameter of the first damping hole 3252 can gradually increase from one end close to the buffer cavity to the other end, forming a funnel shape. This arrangement can make the oil in the buffer cavity flow to the plunger cavity 326. When the oil is dispersed, the effect is better. At the same time, it helps the oil in the plunger cavity 326 flow into the buffer cavity, so that the oil pressure compensation and release are smoother, and the effect of reducing the oil pressure pulsation is improved.

[0036] In this embodiment, the sum of the cross-sectional areas of the plurality of first damping holes 3252 is greater than the sum of the cross-sectional areas of the plurality of second damping holes 3254. Since the volume of the plunger cavity 326 is larger than that of the oil through hole 324, the oil buffer replenishment amount and the absorption amount are reasonably allocated according to the volume difference between the plunger cavity 326 and the oil through hole 324, which can effectively improve the uniformity of the damping effect.

[0037] In this embodiment, a third damping hole 3255 is provided at one end of the conducting tube 3253 close to the annular cover plate 3251. A plurality of third damping holes 3255 are evenly arranged along the circumferential interval of the conducting tube 3253. The third damping holes 3255 are respectively connected to the buffer chamber and the connecting chamber. Since the strength of the annular cover plate 3251 is limited, the number of the first damping holes 3252 arranged on the annular cover plate 3251 is limited. By adding the third damping hole 3255 to the conducting tube 3253, the buffering effect on the plunger chamber 326 can be improved, and the strength of the annular cover plate 3251 can be avoided by opening too many first damping holes 3252. The end of the third damping hole 3255 close to the connecting chamber can be inclined and extended in the direction close to the plunger chamber 326. The diameter of one end of the third damping hole 3255 close to the buffer chamber is smaller than the diameter of the other end. Thereby, the buffering effect on the plunger chamber 326 can be further improved, and the oil can flow between the buffer chamber and the plunger chamber 326.

[0038] In this embodiment, if Figure 3 As shown, a separation ring 3256 is sleeved on the guide tube 3253. The separation ring 3256 separates the buffer chamber into a first chamber and a second chamber. The first chamber is connected to the plunger chamber 326 through the first damping hole 3252. The second chamber is connected to the oil through hole 324 through the second damping hole 3254. By providing the separation ring 3256, the damping and buffering effects of the first damping hole 3252 and the second damping hole 3254 are independent of each other, so as to avoid flow fluctuation or turbulence in the buffer chamber when the oil in the buffer chamber flows out from the first damping hole 3252 and the second damping hole 3254 at the same time, thereby ensuring the stability of reducing the oil pressure pulsation.

[0039] In this embodiment, if Figure 3 As shown, the volume of the first cavity is greater than that of the second cavity. Since the volume of the plunger cavity 326 is large, the oil pressure pulsation generated is large, and the first shock-absorbing hole 3252 needs to be replenished or extracted in time to ensure the shock-absorbing effect. By setting different cavity volumes and reasonably allocating the oil flow, the plunger assembly 30 can be ensured to work under low pressure pulsation.

[0040] In this embodiment, if Figure 4 As shown, the separator ring 3256 may be provided with supply holes 3257. The supply holes 3257 may be arranged at intervals along the circumference of the separator ring 3256. The supply holes 3257 are respectively connected to the first cavity and the second cavity. Thus, the oil in the first cavity and the second cavity can be supplemented with each other without causing turbulence, thereby improving the shock absorption effect on the plunger cavity 326 or the oil through hole 324.

[0041] In this embodiment, a plunger pump is disclosed, and the plunger pump may include a plunger assembly 30 of any one of the above embodiments. Figure 1As shown, the plunger pump may further include a housing assembly 10 and a transmission assembly 20. A chamber is formed inside the housing assembly 10. The plunger assembly 30 is disposed in the inner chamber of the housing assembly 10. The transmission assembly 20 passes through the housing assembly 10 and is drivingly connected to the plunger assembly 30. Thus, the conversion and utilization between hydraulic energy and mechanical energy can be realized.

[0042] In other embodiments, the plunger pump may be a swash plate type axial piston pump or a radial piston pump. When the plunger pump is a swash plate type axial piston pump, the plunger pump may further include a swash plate assembly 40 and a distribution plate assembly 50. The swash plate assembly 40 is used to adjust the efficiency of the plunger assembly 30 in sucking or discharging oil. The distribution plate assembly 50 is used to switch the working state (suction and discharge) of the plunger assembly 30. One end of the swash plate assembly 40 is detachably connected to the inner wall of the housing assembly 10, and the other end is detachably connected to the slipper unit 33 of the plunger assembly 30. One end of the distribution plate assembly 50 is detachably connected to the inner wall of the housing assembly 10, and the other end is detachably connected to the cylinder unit 31. The transmission assembly 20 passes through the housing assembly 10, the swash plate assembly 40, the plunger assembly 30, and the distribution plate assembly 50 in sequence. The transmission assembly 20 is drivingly connected to the swash plate assembly 40, the plunger assembly 30, and the distribution plate assembly 50, respectively.

[0043] Those skilled in the art will appreciate that the above-mentioned embodiments are specific examples for implementing the present disclosure, and in actual applications, various changes may be made thereto in form and detail without departing from the scope of the present disclosure.

Claims

1. A plunger assembly, characterized in that: The plunger assembly comprises: Cylinder unit; The plunger unit comprises a plunger rod, a plunger ball head and a partition; the plunger ball head is integrally formed with one end of the plunger rod; the end of the plunger rod away from the plunger ball head is slidably inserted in the cylinder unit; a plunger cavity is formed between the end of the plunger rod away from the plunger ball head and the cylinder unit; a weight-reducing cavity is provided inside the plunger rod; the weight-reducing cavity passes through to the end of the plunger rod away from the plunger ball head; the partition is located in the weight-reducing cavity; the partition is fixedly connected to the plunger rod The partition part is connected or detachably connected; the partition part divides the weight-reducing cavity into a buffer cavity and a communicating cavity; the communicating cavity is communicated with the plunger cavity; the interior of the plunger ball head is provided with an oil through hole; the oil through hole is communicated with the communicating cavity; a first shock-absorbing hole is formed at one end of the partition part close to the plunger cavity; the first shock-absorbing hole is communicated with the buffer cavity and the plunger cavity respectively; a second shock-absorbing hole is formed at one end of the partition part close to the plunger ball head; the second shock-absorbing hole is communicated with the buffer cavity and the oil through hole respectively; Wherein, the partition part comprises an annular cover plate and a conducting tube; the annular cover plate is fixedly connected to the plunger rod; the annular cover plate is located at the end of the plunger rod away from the plunger ball head; the conducting tube is located in the weight reduction cavity; the conducting tube is detachably connected to the plunger rod and the annular cover plate respectively; the end of the conducting tube close to the annular cover plate is connected to the plunger cavity; the conducting tube, the inner wall of the weight reduction cavity and the annular cover plate form the buffer cavity; the annular cover plate is provided with the first shock-absorbing hole; the end of the conducting tube close to the plunger ball head is provided with the second shock-absorbing hole; A slipper unit is spherically hinged with the plunger ball head; one end of the oil through hole passes through to the surface where the plunger ball head and the slipper unit are in contact.

2. A plunger assembly according to claim 1, characterized in that: A plurality of first shock-absorbing holes are evenly arranged at circumferential intervals along the annular cover plate; a plurality of second shock-absorbing holes are evenly arranged at circumferential intervals along the conducting tube; an axis of the first shock-absorbing hole intersects with an axis of the plunger rod; a plurality of the first shock-absorbing holes are dispersed near one end of the plunger cavity; a plurality of the first shock-absorbing holes are close to one end of the buffer cavity.

3. A plunger assembly according to claim 1, characterized in that: A diameter of one end of the first shock-absorbing hole close to the plunger cavity is larger than a diameter of one end of the first shock-absorbing hole close to the buffer cavity.

4. A plunger assembly according to claim 2, characterized in that: The sum of cross-sectional areas of the first shock-absorbing holes is greater than the sum of cross-sectional areas of the second shock-absorbing holes.

5. A plunger assembly according to claim 1, characterized in that: A third shock-absorbing hole is formed at one end of the conducting tube close to the annular cover plate; a plurality of the third shock-absorbing holes are evenly arranged at intervals along the circumference of the conducting tube; and the third shock-absorbing holes are respectively connected to the buffer chamber and the connecting chamber.

6. A plunger assembly according to claim 1, characterized in that: A separation ring is sleeved on the conducting tube; the separation ring separates the buffer chamber into a first chamber and a second chamber; the first chamber is connected to the plunger chamber through the first damping hole; the second chamber is connected to the oil through hole through the second damping hole.

7. A plunger assembly according to claim 6, characterized in that: The volume of the first cavity is greater than the volume of the second cavity.

8. A plunger assembly according to claim 6, characterized in that: The separation ring is provided with supply holes; the supply holes are arranged at intervals along the circumference of the separation ring; and the supply holes are respectively connected with the first cavity and the second cavity.

9. A plunger pump, comprising a plunger assembly according to any one of claims 1 to 8, characterized in that: The plunger pump also includes: A housing assembly, wherein a chamber is formed inside the housing assembly; the plunger assembly is disposed in the internal chamber of the housing assembly; A transmission assembly is driven and connected to the plunger assembly through the housing assembly.

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