Multi-stage regulation and control type pulsation reducing plunger

Abstract

A multi-stage regulation and control type plunger capable of reducing pulsation comprises a plunger body, and an overflowing channel is formed in the plunger body. At least two limiting devices are sequentially arranged in the flowing channel in the oil flowing direction, at least two elastic plates are connected to the portion, between the two limiting devices, of the flowing channel in a sliding mode, an elastic device is arranged between the two elastic plates, and at least two elastic pieces are sequentially arranged on the elastic device in a nested mode from outside to inside. In the liquid discharging process, oil pressure pulsation enables the surface of the elastic plate to be stressed, so that the elastic plate and the elastic device deform, in the first pulsation stage, the elastic plate deforms, pulsation is reduced, and the elastic device is not compressed; in the second pulsation stage, one elastic piece of the elastic device is compressed; and in the third pulsation stage, the two elastic pieces of the elastic device are compressed at the same time.

Description

Technical Field

[0001] The invention relates to the technical field of plunger pump oil pressure control, and in particular to a multi-stage regulating plunger for reducing pulsation. Background Art

[0002] The plunger pump is the core of many hydraulic systems. Its main function is to rely on the reciprocating motion of the plunger in the cylinder to change the volume of the sealed working chamber to achieve oil suction and oil pressure for the subsequent use of hydraulic and pneumatic devices. Its main principle is that as the main shaft rotates, the internal space of the plunger cavity becomes larger and low-pressure oil is sucked in, and the space becomes smaller and high-pressure oil is discharged. Therefore, the oil pressure and flow rate changes inside the plunger will be very obvious. Oil pressure pulsation mainly refers to a kind of pressure that acts unevenly on the object being acted on, with a more concentrated pressure in one part and a more dispersed pressure in another part. This pressure does not last long at a time and may show a certain periodicity, which can easily lead to increased noise and vibration of the plunger pump, reduce the working efficiency of the plunger pump, and may even damage the internal structure of the plunger pump, causing serious consequences such as oil leakage.

[0003] The existing method of reducing oil pressure pulsation is to install a pulsation attenuator inside the plunger pump, which becomes a flexible and effective method when the layout of the plunger pump pipeline is limited. With the development of electronic intelligent technology, the structure of the pulsation attenuator is becoming more and more complex and large, the parameters of the circuit are difficult to adjust, the manufacturing cost and difficulty are rising, the space inside the plunger is small and the number of plungers is large, which also hinders the popularization and application of pulsation attenuators in the field of plunger pumps. Summary of the invention

[0004] In view of the shortcomings of the background technology, the object of the present invention is to provide a multi-stage control type plunger for reducing pulsation.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A multi-stage regulating plunger for reducing pulsation, comprising a plunger body, wherein a flow passage is arranged inside the plunger body; at least two limit devices are arranged in sequence in the flow passage along the flow direction of the oil, the flow passage is slidably connected with at least two elastic plates between the two limit devices, an elastic device is arranged between the two elastic plates, and at least two elastic members are nested in sequence in the elastic device from the outside to the inside;

[0007] During the discharge process, the oil pressure pulsation causes the surface of the elastic plate to be subjected to pressure, thereby causing the elastic plate and the elastic device to deform. In the first pulsation stage, the deformation of the spring plate reduces the pulsation, and the elastic device is not compressed; in the second pulsation stage, one of the elastic parts of the elastic device is compressed; in the third pulsation stage, the two elastic parts of the elastic device are compressed at the same time.

[0008] Furthermore, a plurality of filter holes are arranged equidistantly on the outer surfaces of the two elastic plates.

[0009] Furthermore, the elastic device is sequentially nested with a first elastic member and a second elastic member from outside to inside, the elastic coefficient of the first elastic member is smaller than the elastic coefficient of the second elastic member, and the length and radius of the first elastic member are greater than the length and radius of the second elastic member.

[0010] Furthermore, a mounting hole is provided at the middle position of the two elastic plates, a fastener is provided in the mounting hole, and the second elastic member is sleeved on the fastener.

[0011] Furthermore, the second elastic member is interference-fitted with the fastener, the fastener is provided with barbs, and both ends of the second elastic member abut against the barbs.

[0012] Furthermore, a supporting boss is provided at the middle position of one side opposite to the two elastic plates, the outer diameter of the supporting boss is equal to the outer diameter of the first elastic member, and the two ends of the first elastic member are respectively sleeved on the two supporting bosses.

[0013] Furthermore, the limiting device is a limiting boss fixed on the cavity wall of the flow channel, and when the elastic device does not deform, the two elastic plates respectively abut against the two limiting bosses.

[0014] Furthermore, a support body is provided at an edge position of one side opposite to the two elastic plates, and the support body abuts against a cavity wall of the flow channel.

[0015] Furthermore, the plunger body comprises a rod portion and a head portion, the rod portion and the head portion are an integral structure, and the head portion is connected to a driving mechanism in the plunger pump.

[0016] Furthermore, a liquid inlet hole and a liquid outlet hole are respectively provided at both ends of the flow channel, the liquid inlet hole is provided at the end of the rod portion, and the liquid outlet hole is provided at the end of the head portion.

[0017] The beneficial effects of the present invention are:

[0018] 1. The present invention proposes a multi-stage control type plunger for reducing pulsation. Different oil pressure pulsations will cause the surface of the elastic plate to be subjected to different pressures, thereby causing the elastic plate and the elastic member to deform. The effect can be achieved under different pressure environments. The stiffness coefficient of the elastic member can also be selected to meet the needs of different types of plunger pumps, thereby realizing the multi-stage control function of oil pulsation.

[0019] 2. The present invention proposes a multi-stage adjustable plunger for reducing pulsation. Through the setting of an elastic plate, the elastic plate is a layer of honeycomb mesh structure. The oil can flow freely into and out of the elastic plate, and can undergo elastic deformation to absorb energy. The oil pulsation is reduced by deformation, and the oil pulsation is absorbed and evenly transmitted to the spring group.

[0020] 3. The present invention proposes a multi-stage adjustable plunger for reducing pulsation. Through the setting of a support body, the support body is fixed to the edge of the elastic plate and can reciprocate with the elastic plate to play a reinforcing role.

[0021] 4. The present invention proposes a multi-stage control type plunger for reducing pulsation. Through the setting of a limit device, the limit boss is fixed on the wall of the plunger cavity to limit the maximum moving distance of the elastic plates at both ends. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 A schematic diagram of a multi-stage regulating plunger for reducing pulsation according to the present invention;

[0024] Figure 2 It is a schematic diagram of deformation of only the elastic plate of a multi-stage control type pulsation reducing plunger of the present invention;

[0025] Figure 3 It is a schematic diagram of compressing only the first elastic member of a multi-stage control type pulsation reducing plunger of the present invention;

[0026] Figure 4 It is a schematic diagram of a multi-stage control type pulsation reducing plunger of the present invention compressing a first elastic member and a second elastic member at the same time;

[0027] Figure 5 This is a comparison chart of the pressure pulsation suppression effect of a multi-stage control type pulsation reducing plunger under different outlet pressures of the present invention.

[0028] In the figure, 10, plunger body; 101, flow channel; 102, head; 20, elastic plate; 201, filter hole; 301, first elastic member; 302, second elastic member; 401, support body; 402, limit device; 403, support boss; 404, fastener. DETAILED DESCRIPTION

[0029] Combine the following Figure 1-5The present invention is described in detail.

[0030] A multi-stage regulating plunger for reducing pulsation comprises a plunger body 10, wherein a flow passage 101 is arranged inside the plunger body 10; at least two limit devices 402 are arranged in sequence in the flow passage 101, and at least two elastic plates 20 are slidably connected between the two limit devices 402 in the flow passage 101, an elastic device is arranged between the two elastic plates 20, and at least two elastic members are nested in the elastic device from the outside to the inside;

[0031] During the discharge process, the oil pressure pulsation causes the surface of the elastic plate 20 to be subjected to pressure, thereby causing the elastic plate 20 and the elastic device to deform. In the first pulsation stage, the deformation of the elastic plate reduces the pulsation, and the elastic device is not compressed; in the second pulsation stage, one of the elastic parts of the elastic device is compressed; in the third pulsation stage, the two elastic parts of the elastic device are compressed at the same time. The first pulsation stage is a low pulsation stage, the second pulsation stage is a medium pulsation stage, and the third pulsation stage is a high pulsation stage.

[0032] Specifically, the number of elastic members nested from outside to inside and the elastic coefficient can be adjusted according to the actual situation of the plunger. If two elastic members cannot effectively reduce the pulsation energy, three or more elastic members can be set.

[0033] like Figure 1 As shown, the outer surfaces of the two elastic plates 20 are arranged with a plurality of filter holes 201 at equal intervals. The elastic plate 20 is a honeycomb structure, and the filter holes 201 cannot be too small or too dense so that the oil can flow in and out freely. The elastic plate 20 itself can deform to absorb a small part of the energy, thereby reducing the pulsation. In order to meet the requirements of strength and elasticity, the elastic plate 20 can be made by stacking metal sheets and polyester sheets. A groove is provided on the wall of the plunger cavity, and the elastic plate 20 is embedded in the groove and can slide. The depth of the groove is set small.

[0034] In this embodiment, the elastic device is nested with a first elastic member 301 and a second elastic member 302 in sequence from the outside to the inside. The elastic coefficient of the first elastic member 301 is smaller than the elastic coefficient of the second elastic member 302, and the length and radius of the first elastic member 301 are the length and radius of the second elastic member 302.

[0035] In this embodiment, a mounting hole is provided in the middle of the two elastic plates 20, and a fastener 404 is provided in the mounting hole. The two ends of the second elastic member 302 are respectively sleeved on the two fasteners 404. A circular hole is opened in the middle of the two elastic plates 20 to install the fastener 404 such as a bolt. It should be noted that the diameter of the circular hole should be as small as possible to ensure that there is enough oil flow on the surface of the elastic plate 20. The second elastic member 302 is sleeved on the fastener 404, and a barbed metal sheet is embedded in the tail of the fastener 404 to prevent the second elastic member 302 from falling off the bolt when the plunger moves at high speed. Two supporting bosses 403 are fixed to the inner surface of each elastic plate 20, which are respectively located at the same radius above and below the center of the elastic plate 20.

[0036] In this embodiment, the second elastic member 302 and the fastener 404 are interference fit, the fastener 404 is provided with barbs, and both ends of the second elastic member 302 abut against the barbs.

[0037] In this embodiment, a support boss 403 is provided at the middle position of one side opposite to the two elastic plates 20. The outer diameter of the support boss 403 is equal to the outer diameter of the first elastic member 301. The two ends of the first elastic member 301 are respectively sleeved on the two support bosses 403. The first elastic member 301 is sleeved on the support boss 403, and an anti-slip material can be attached to the surface of the support boss 403 to improve the stability of the device. Since the length of the first elastic member 301 is the maximum value of the distance between the two elastic plates 20, there is no need to add protective measures to prevent it from falling off. The length of the first elastic member 301 is longer than that of the second elastic member 302, but the stiffness coefficient of the first elastic member 301 is smaller than that of the second elastic member 302. Therefore, when the oil pressure pulsation is small, the first elastic member 301 is compressed first, and when the pulsation is large, the first and second elastic members 301 are compressed together to achieve multi-stage regulation of oil pulsation.

[0038] Furthermore, the limiting device 402 is a limiting boss fixed on the cavity wall of the flow channel 101, and when the elastic device does not deform, the two elastic plates 20 are respectively in contact with the two limiting bosses. The upper and lower cavity walls on the left side of the elastic plate 20 are fixed with limiting bosses, which limit the maximum distance of the upper elastic plate 20 moving upward, while there is no limit on the downward movement, and the same is true for the lower elastic plate 20. In order to improve the stability of the elastic plate 20 when sliding left and right, a wedge-shaped support body 401 is fixed on the upper and lower inner surfaces of the inner side of the elastic plate 20, which plays the role of reinforcing rib support. Preferably, in order to adapt to the high-intensity working environment in the plunger cavity, the support body 401, the limiting device 402, the support boss 403 and the fastener 404 are made of metal with high strength and high wear resistance.

[0039] In this embodiment, a support body 401 is disposed at the edge of one side opposite to the other of the two elastic plates 20 , and the support body 401 abuts against the cavity wall of the flow channel 101 .

[0040] In this embodiment, the plunger body 10 includes a rod and a head 102 , wherein the rod and the head 102 are an integral structure, and the head 102 is connected to a driving mechanism in the plunger pump.

[0041] Furthermore, a liquid inlet hole and a liquid outlet hole are respectively provided at both ends of the flow channel 101 . The liquid inlet hole is provided at the end of the rod portion, and the liquid outlet hole is provided at the end of the head portion 102 .

[0042] like Figure 2 As shown, when the plunger pump is working, the oil enters from the liquid inlet, flows from the lower chamber through the lower elastic plate 20 into the middle chamber, and then flows from the middle chamber through the upper elastic plate 20 into the upper chamber and into the sliding shoe. The flow direction of the oil is from right to left ( Figure 2 The direction of the oil pressure on the surface of the elastic plate 20 is also from bottom to top, and the elastic plate 20 tends to move upward. The oil pressure under low pulsation is relatively small. Since there is friction between the elastic plate 20, the wedge-shaped support body 401 and the cavity wall, the surface pressure is not enough to move the elastic plate 20. The elastic plate 20 at the left and lower ends deforms in the direction of oil flow to absorb a small amount of fluctuation energy. At this time, the inner and first elastic members 301 are not compressed, and only the elastic plate 20 itself deforms to reduce the oil pulsation.

[0043] like Figure 3 As shown, under medium pulsation, the oil also flows from the lower chamber through the elastic plate 20 at the lower end into the middle chamber, and then from the middle chamber through the elastic plate 20 into the upper chamber. Due to the high oil pressure, the deformation of the elastic plate 20 reaches the maximum. At this time, the elastic plate 20 at the lower end moves upward, and the elastic plate 20 has reached the maximum limit. The first elastic member 301 is compressed to provide support for the elastic plate 20 to reduce the oil pulsation. Since the support force provided by the part of the first elastic member 301 that is longer than the second elastic member 302 is sufficient to neutralize the oil pulsation, the elastic plate 20 only compresses the first elastic member 301 while the length of the second elastic member 302 remains unchanged. In this case, the elastic plate 20 and the first elastic member 301 jointly participate in regulating the oil pulsation.

[0044] like Figure 4As shown, when the pulsation is large, the oil also flows from the lower chamber through the elastic plate 20 at the lower end into the middle chamber, and then flows from the middle chamber through the elastic plate 20 into the upper chamber. Because the oil pressure is very large, the deformation of the elastic plate 20 reaches the maximum, the elastic plate 20 at the lower end moves to the left, and the elastic plate 20 has reached the maximum limit. At this time, the elastic force generated by the deformation of the elastic plate 20 itself and the supporting force provided by the part of the first elastic member 301 that is longer than the second elastic member 302 are not enough to neutralize the oil pressure fluctuation. When the first elastic member 301 is compressed to the same length as the second elastic member 302, the first elastic member 301 is compressed at the same time, and the two together provide supporting force for the elastic plate 20 to offset the oil pulsation pressure. In this case, the elastic plate 20, the first elastic member 301 and the second elastic member 302 are all involved in the regulation of oil pulsation, and the neutralizing force that can be provided is much greater than that of the previous two cases.

[0045] Furthermore, in order to more accurately select the size and stiffness coefficient of the spring, the specific relationship between the compression of the spring and the oil pulsation will be calculated below.

[0046] The pressure change in the plunger chamber can be expressed by the following formula: p is the pressure in the plunger chamber, K e is the elastic modulus of the hydraulic oil, V pc is the volume of the plunger cavity, Q lp Q is the volume flow from the plunger pump inlet to the plunger chamber, hp Q is the volume flow from the plunger chamber to the plunger pump outlet. l is the volume flow rate leaking from each friction pair.

[0047] The volume of the plunger cavity can be expressed as: Where V is the volume of the plunger cavity when the plunger is at the outer dead center, θ is the plunger rotation angle, Dp is the plunger diameter, R is the plunger distribution circle radius, and β is the swash plate inclination angle.

[0048] The volume flow from the plunger pump inlet to the plunger chamber or from the plunger chamber to the plunger pump outlet can be expressed as: Where C is the flow coefficient, A lp , A hp are the flow areas between the inlet and outlet of the plunger pump and the plunger cavity, respectively, and their values ​​are determined by the structure of the distribution plate. ρ is the density of the hydraulic oil, and p l 、p h are the pressures at the inlet and outlet of the plunger pump respectively.

[0049] The pressure on the surface of the elastic plate 20 is: F=p*S; wherein S is the solid area of ​​the elastic plate 20 .

[0050] When only the first elastic member 301 is compressed, the deformation of the first elastic member 301 is: X1 = F / k1; when the double springs are compressed, the deformation of the second elastic member 302 is: When the double spring is compressed, the deformation of the first elastic member 301 is: X1=X+l1-l2; wherein k1 and k2 are the stiffness coefficients of the first elastic member 301 and the second elastic member 302 respectively, and l1 and l2 are the original lengths of the first elastic member 301 and the second elastic member 302 respectively.

[0051] The pressure pulsation of an axial piston pump refers to the phenomenon that the outlet pressure of the pump fluctuates periodically due to the reciprocating motion of the piston and the periodic switching of the flow distribution mechanism during the operation of the pump. The pressure pulsation rate is usually used to measure the pressure pulsation, and its expression is as follows: Among them, p max is the maximum pressure, p min is the minimum pressure, p avg is the average pressure.

[0052] like Figure 5 As shown, as the outlet pressure increases, the pressure fluctuation rate also increases. Under high pressure, the pressure feedback effect is more significant, the leakage flow increases, the oil compressibility is more obvious, the flow distribution process is more complicated, and the mechanical deformation and fluid dynamics effects become more prominent. In addition, changes in system response characteristics, the influence of material properties, temperature changes, and possible resonance effects will all aggravate pressure fluctuations. These factors interact with each other, resulting in increased unevenness in piston movement and intensified flow fluctuations, which ultimately increases the pressure fluctuation rate as the outlet pressure increases. Compared with the original plunger, the plunger of the present invention can significantly reduce the outlet pressure pulsation rate of the axial piston pump. As the outlet pressure increases, the pressure pulsation suppression effect of the device of the present invention is more obvious.

[0053] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable those skilled in the art to understand the content of the present invention and implement it, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A multi-stage control type pulsation reducing plunger, comprising a plunger body, characterized in that: A flow passage is provided inside the plunger body; at least two limit devices are sequentially provided in the flow passage, at least two elastic plates are slidably connected between the two limit devices, an elastic device is provided between the two elastic plates, and the elastic device includes at least two elastic members sequentially nested from the outside to the inside; During the discharge process, the oil pressure pulsation causes the surface of the elastic plate to be subjected to pressure, thereby causing the elastic plate and the elastic device to deform. In the first pulsation stage, the elastic plate deforms to reduce the pulsation, and the elastic device is not compressed. In the second pulsation stage, one of the elastic members of the elastic device is compressed; in the third pulsation stage, the two elastic members of the elastic device are compressed at the same time.

2. A multi-stage control type pulsation reducing plunger as claimed in claim 1, characterized in that: A plurality of filter holes are arranged equidistantly on the outer surfaces of the two elastic plates.

3. A multi-stage control type pulsation reducing plunger as claimed in claim 1, characterized in that: The elastic device is nested with a first elastic member and a second elastic member in sequence from outside to inside. The elastic coefficient of the first elastic member is smaller than the elastic coefficient of the second elastic member. The length and radius of the first elastic member are greater than the length and radius of the second elastic member.

4. A multi-stage control type pulsation reducing plunger as claimed in claim 3, characterized in that: A mounting hole is provided at the middle position of the two elastic plates, a fastener is provided in the mounting hole, and the second elastic member is sleeved on the fastener.

5. A multi-stage control type pulsation reducing plunger as claimed in claim 4, characterized in that: The second elastic member is interference-fitted with the fastener, the fastener is provided with barbs, and both ends of the second elastic member abut against the barbs.

6. A multi-stage control type pulsation reducing plunger as claimed in claim 1, characterized in that: A supporting boss is provided at the middle position of one side opposite to the two elastic plates, the outer diameter of the supporting boss is equal to the outer diameter of the first elastic member, and the two ends of the first elastic member are respectively sleeved on the two supporting bosses.

7. A multi-stage control type pulsation reducing plunger as claimed in claim 6, characterized in that: The limiting device is a limiting boss fixed on the cavity wall of the flow passage, and when the elastic device does not deform, the two elastic plates are respectively in contact with the two limiting bosses.

8. A multi-stage control type pulsation reducing plunger as claimed in claim 1, characterized in that: A support body is provided at the edge position of one side opposite to the two elastic plates, and the support body abuts against the cavity wall of the flow channel.

9. A multi-stage control type pulsation reducing plunger as claimed in claim 1, characterized in that: The plunger body comprises a rod portion and a head portion, wherein the rod portion and the head portion are an integral structure, and the head portion is connected to a driving mechanism in the plunger pump.

10. A multi-stage control type pulsation reducing plunger as claimed in claim 9, characterized in that: A liquid inlet hole and a liquid outlet hole are respectively arranged at both ends of the flow passage, the liquid inlet hole is arranged at the end of the rod portion, and the liquid outlet hole is arranged at the end of the head portion.

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