A hydraulic dual cylinder piston pump and hydraulic tool

Abstract

This invention provides a hydraulic dual-cylinder plunger pump and a hydraulic tool. The hydraulic dual-cylinder plunger pump includes a cylinder body, plungers, and a plunger check valve. A piston chamber is formed within the cylinder body, and the cylinder body has an oil inlet and an oil outlet. A piston portion is provided at one end of the plunger, and the piston portion is slidably mounted within the piston chamber. The upper end face of the piston portion mates with the piston chamber to form a first working chamber, which communicates with the oil inlet. The lower end face of the piston portion mates with the piston chamber to form a second working chamber, which communicates with the oil outlet. A plunger oil passage is formed on the piston portion. The plunger check valve is located within the plunger oil passage and is used to open when the pressure in the first working chamber is greater than the pressure in the second working chamber, thereby connecting the first and second working chambers. The hydraulic dual-cylinder plunger pump of this invention has a single-plunger, dual-cylinder structure. The first and second working chambers serve as the oil inlet chambers when the plunger pushes upward and downward, respectively, enabling the hydraulic dual-cylinder plunger pump to perform work throughout its entire stroke.

Description

Technical Field

[0001] This invention relates to the field of hydraulic tool technology, and in particular to a hydraulic dual-cylinder plunger pump and a hydraulic tool. Background Technology

[0002] Most existing hydraulic tools use single-cylinder piston pumps with a cam and spring mechanism. The pump uses a cam to push the piston, which compresses the hydraulic oil while squeezing the spring, creating high-pressure oil that drives hydraulic actuators (such as cylinders or hydraulic motors). The spring then pushes the piston back to its original position, achieving the reciprocating motion. In this type of pump, half of the stroke is the spring return stroke, which does no work. This, along with the other half of the stroke, creates a large alternating load in the system, resulting in unstable operation, high vibration, significant impact on the drive unit (such as an electric motor or gasoline engine), and high energy consumption. Summary of the Invention

[0003] The purpose of this invention is to provide a hydraulic dual-cylinder plunger pump and a hydraulic tool, which aims to solve the problems of unstable operation, large vibration, large impact on the drive device, and high additional energy consumption of existing hydraulic tools.

[0004] To solve the above-mentioned technical problems, embodiments of the present invention provide a hydraulic dual-cylinder plunger pump, comprising:

[0005] A cylinder body, wherein a piston chamber is formed within the cylinder body, and an oil inlet and an oil outlet communicating with the piston chamber are provided on the cylinder wall of the cylinder body;

[0006] A plunger, one end of which is provided with a piston portion, which is slidably mounted in the piston chamber. The upper end face of the piston portion cooperates with the piston chamber to form a first working chamber, which is connected to the oil inlet. The lower end face of the piston portion cooperates with the piston chamber to form a second working chamber, which is connected to the oil outlet. A plunger oil passage is provided on the piston portion.

[0007] A plunger check valve is disposed in the plunger oil passage and is used to open when the pressure in the first working chamber is greater than the pressure in the second working chamber, so as to connect the first working chamber and the second working chamber.

[0008] Preferably, a bushing is provided in the cylinder body, the bushing is sleeved outside the piston part, the upper side of the bushing and the upper end face of the piston part cooperate to form the piston cavity to form the first working cavity, and the bushing and the piston part form the second working cavity.

[0009] Preferably, the lower end face of the piston portion is a first annular surface, and the inner peripheral side of the bushing is provided with a second annular surface facing the piston portion, and the piston cavity forms the second working cavity between the second annular surface and the first annular surface.

[0010] Preferably, the bushing is provided with a bushing oil passage that connects the oil outlet and the second working chamber.

[0011] Preferably, the bushing oil passage is arranged to extend radially along the bushing and is located on the upper side of the second annular surface.

[0012] Preferably, the plunger oil passage extends through the upper end face of the piston portion and the first annular surface.

[0013] Preferably, the plunger oil passage includes:

[0014] The installation channel is located on the upper end face of the piston portion, and one end of the installation channel is opened on the upper side of the first annular surface. The plunger check valve is located inside the installation channel.

[0015] A connecting channel, one end of which penetrates the inner wall of the mounting channel, and the other end of which penetrates the first annular surface, wherein multiple connecting channels are provided at intervals along the circumference of the mounting channel.

[0016] Preferably, the plunger check valve includes:

[0017] A valve seat is disposed within the plunger oil passage, and the valve seat is provided with an oil inlet passage that connects the first working chamber and the plunger oil passage.

[0018] A valve ball is located on the side of the oil inlet channel away from the first working chamber. When the plunger slides downward, the valve ball blocks the port of the oil inlet channel away from the first working chamber, thereby closing the plunger check valve. When the plunger slides upward, the valve ball separates from the valve seat and opens the port of the oil inlet channel, thereby opening the plunger check valve.

[0019] Preferably, an oil suction check valve is provided at the oil inlet, which is used to open when the pressure in the first working chamber is less than the pressure in the oil tank at the other end of the oil inlet;

[0020] An oil outlet check valve is provided at the oil outlet. The oil outlet check valve opens when the pressure in the second working chamber is greater than the pressure of the working cylinder at the other end of the oil outlet.

[0021] To achieve the above objectives, the present invention also provides a hydraulic tool, comprising:

[0022] The aforementioned hydraulic dual-cylinder piston pump;

[0023] The oil tank is connected to the oil inlet of the hydraulic dual-cylinder plunger pump;

[0024] The working cylinder is connected to the oil outlet of the hydraulic dual-cylinder plunger pump;

[0025] A drive unit is connected to the end of the plunger of the hydraulic twin-cylinder plunger pump away from the piston section, and is used to drive the piston section to slide within the piston chamber.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The hydraulic dual-cylinder plunger pump of the present invention has a first working chamber and a second working chamber, i.e., a double cylinder, between the plunger and the cylinder body, making the hydraulic dual-cylinder plunger pump a single-plunger double-cylinder structure. The first working chamber and the second working chamber are respectively connected to the oil inlet and oil outlet of the piston chamber, and a plunger check valve is provided on the plunger to connect the first working chamber and the second working chamber. The plunger check valve opens when the pressure in the first working chamber is greater than the pressure in the second working chamber. In this way, the first working chamber and the second working chamber serve as the oil inlet chamber when the plunger is pushed up and the oil inlet chamber when the plunger is pulled down, respectively, realizing the full stroke of the hydraulic dual-cylinder plunger pump, which can achieve the effects of smoothing alternating load, reducing vibration, and improving energy utilization efficiency. Attached Figure Description

[0028] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0029] Figure 1 This is a schematic diagram of the hydraulic dual-cylinder plunger pump in an embodiment of the present invention;

[0030] Figure 2 for Figure 1 One of the cross-sectional views of a medium-pressure hydraulic twin-cylinder piston pump;

[0031] Figure 3 for Figure 1 Second sectional view of a medium-pressure hydraulic double-cylinder piston pump;

[0032] Figure 4 This is a cross-sectional view of the hydraulic tool in an embodiment of the present invention;

[0033] Figure 5 for Figure 4 A magnified view of a section at point A, where the plunger is located at the lowest point;

[0034] Figure 6 for Figure 5A schematic diagram of the structure after the central plunger moves upward;

[0035] Figure 7 for Figure 6 Hydraulic oil flow diagram when the middle plunger moves upward;

[0036] Figure 8 for Figure 6 A schematic diagram of the structure after the middle plunger moves upward to the highest point;

[0037] Figure 9 for Figure 8 Hydraulic oil flow diagram as the middle plunger moves downward;

[0038] Figure 10 A comparison chart of the motor power curves required for one revolution of a single-cylinder plunger pump and a hydraulic twin-cylinder plunger pump.

[0039] Explanation of reference numerals in the accompanying drawings of this invention:

[0040] Hydraulic tool 1000, hydraulic double-cylinder plunger pump 100, bushing 1, bushing oil passage 11, second annular surface 12, second annular seal 13, plunger 2, plunger oil passage 21, first annular surface 22, mounting channel 23, connecting channel 24, annular limiting surface 25, first annular seal 26, piston part 27, rod part 28, plunger check valve 3, valve seat 31, oil inlet channel 32, valve ball 33, second working chamber 4, cylinder body 200, piston chamber 210, first working chamber 220, oil inlet 230, oil outlet 240, suction check valve 250, discharge check valve 260, filter 270, drive device 300, eccentric wheel mechanism 310, push-pull rod 311, eccentric wheel 312, reduction gearbox 320, working cylinder 400, oil tank 500.

[0041] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0044] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0045] To address the problems of low energy efficiency and no work done during half the stroke of a single-cylinder piston pump, this invention provides a hydraulic dual-cylinder piston pump, which can be used in hydraulic tools such as hydraulic pliers. Figures 1 to 3 A preferred embodiment of the hydraulic dual-cylinder plunger pump provided by the present invention is shown. Figures 4 to 8 A preferred embodiment of the hydraulic twin-cylinder piston pump provided by the present invention is shown for use in hydraulic tools.

[0046] Please see Figures 1 to 5 In this embodiment, the hydraulic dual-cylinder plunger pump 100 includes a cylinder body 200, a plunger 2, and a plunger check valve 3. A piston chamber 210 is formed inside the cylinder body 200. An oil inlet 230 and an oil outlet 240 communicating with the piston chamber 210 are provided on the cylinder wall of the cylinder body 200. A piston part 27 is provided at one end of the plunger 2. The piston part 27 is slidably installed in the piston chamber 210. The upper end face of the piston part 27 cooperates with the piston chamber 210 to form a first working chamber 220, which communicates with the oil inlet 230. The lower end face of the piston part 27 cooperates with the piston chamber 210 to form a second working chamber 4, which communicates with the oil outlet 240. A plunger oil passage 21 is provided on the piston part 27. The plunger check valve 3 is provided in the plunger oil passage 21 and is used to open when the pressure in the first working chamber 220 is greater than the pressure in the second working chamber 4, so as to connect the first working chamber 220 and the second working chamber 4.

[0047] Specifically, the cylinder body 200 may be part of the hydraulic dual-cylinder plunger pump 100, meaning the hydraulic dual-cylinder plunger pump 100 includes the cylinder body 200; alternatively, the cylinder body 200 may not be part of the hydraulic dual-cylinder plunger pump 100, meaning the hydraulic dual-cylinder plunger pump 100 does not include the cylinder body 200. When the hydraulic dual-cylinder plunger pump 100 is installed on the hydraulic tool 1000, the cylinder body 200 is formed by a portion of the hydraulic tool 1000 that is independent of the hydraulic dual-cylinder plunger pump 100. Furthermore, only a portion of the cylinder body 200 may be part of the hydraulic... A portion of the dual-cylinder plunger pump 100, namely the hydraulic dual-cylinder plunger pump 100, includes a portion of the cylinder body 200. The other portion of the cylinder body 200 and the hydraulic dual-cylinder plunger pump 100 are two independent parts on the hydraulic tool 1000. When the hydraulic dual-cylinder plunger pump 100 is installed on the hydraulic tool 1000, the portion of the cylinder body 200 provided on the hydraulic dual-cylinder plunger pump 100 and the other portion of the cylinder body 200 provided on the hydraulic tool 1000 combine to form a complete cylinder body 200.

[0048] The cylinder wall of cylinder block 200 has an oil inlet 230 and an oil outlet 240 that communicate with piston chamber 210. Please refer to [link / reference]. Figure 4 The hydraulic tool 1000 includes an oil tank 500 and a working cylinder 400. The oil tank 500 and the working cylinder 400 are respectively connected to the oil inlet 230 and the oil outlet 240 of the cylinder body 200, so that the hydraulic oil in the oil tank 500 can enter the piston chamber 210 from the oil inlet 230 of the cylinder body 200, and then enter the working cylinder 400 from the oil outlet 240 of the cylinder body 200, so as to drive the piston rod in the working cylinder 400 to move.

[0049] One end of the plunger 2 is slidably disposed within the piston chamber 210 of the cylinder block 200 along the axial direction of the plunger 2, which is vertical. The end of the plunger 2 located within the piston chamber 210 is the upper end of the plunger 2. The plunger 2 typically includes a piston portion 27 and a rod portion 28. The rod portion 28 is rod-shaped and extends vertically. The upper end of the rod portion 28 extends into the piston chamber 210, and the lower end of the rod portion 28 is power-coupled to the drive device 300 of the hydraulic tool 1000, for driving the plunger 2 to reciprocate vertically via the drive device 300. The piston portion 27 is disposed at the upper end of the rod portion 28, and the diameter of the piston portion 27 is larger than the diameter of the rod portion 28. The drive device 300 can be an electric motor or a gasoline engine, etc. The following description will use an electric motor as an example of the drive device 300.

[0050] The upper end of the plunger 2 is located inside the piston cavity 210 and is provided with a piston portion 27. The outer surface of the plunger 2 and the inner wall of the piston cavity 210 enclose a first working cavity 220 and a second working cavity 4 that are not directly connected. Thus, the first working cavity 220 and the second working cavity 4 are formed at intervals within the piston cavity 210 by the plunger 2. Since the first working cavity 220 is located on the upper side of the piston portion 27 and the second working cavity 4 is located on the lower side of the piston portion 27, when the plunger 2 slides upward, the cavity volume of the first working cavity 220 will gradually decrease and the cavity volume of the second working cavity 4 will gradually increase; while when the plunger 2 slides downward, the cavity volume of the first working cavity 220 will gradually increase and the cavity volume of the second working cavity 4 will gradually decrease.

[0051] A plunger oil passage 21 is provided on the piston section 27, which connects the first working chamber 220 and the second working chamber 4. Since the first working chamber 220 and the second working chamber 4 are respectively connected to the oil inlet 230 and the oil outlet 240 of the piston chamber 210, the hydraulic oil in the oil tank 500 can enter the first working chamber 220 from the oil inlet 230 of the cylinder body 200, and then flow through the plunger oil passage 21 and the second working chamber 4 in sequence, before entering the working cylinder 400 from the oil outlet 240 of the cylinder body 200.

[0052] A plunger check valve 3 is provided in the plunger oil passage 21. When the plunger check valve 3 is open, the first working chamber 220 and the second working chamber 4 are connected through the plunger check valve 3. When the plunger check valve 3 is closed, the first working chamber 220 and the second working chamber 4 are isolated. The plunger check valve 3 can be opened when the pressure in the first working chamber 220 is greater than the pressure in the second working chamber 4.

[0053] Please see Figure 5 and Figure 6 When the drive device 300 pushes the plunger 2 upward, the cavity volume of the first working chamber 220 decreases, the hydraulic oil pressure in the first working chamber 220 increases, the plunger check valve 3 opens, and the hydraulic oil in the oil tank 500 can enter the first working chamber 220 from the oil inlet 230, and then flow through the plunger oil passage 21 and the second working chamber 4 in sequence, and enter the working cylinder 400 from the oil outlet 240.

[0054] Please see Figure 8 When the plunger 2 reaches its highest point, the upward stroke of the plunger 2 ends, and the drive device 300 begins to pull the plunger 2 downward. The cavity volume of the first working chamber 220 increases, the hydraulic oil pressure in the first working chamber 220 decreases, and the hydraulic oil in the oil tank 500 can enter the first working chamber 220 from the oil inlet 230. At the same time, the plunger check valve 3 closes to isolate the first working chamber 220 from the second working chamber 4, and the cavity volume of the second working chamber 4 decreases, thereby forcing the hydraulic oil in the second working chamber 4 into the working cylinder 400 through the oil outlet 240.

[0055] Thus, the first working chamber 220 and the second working chamber 4 serve as the oil inlet chambers when the plunger 2 pushes upward and when the plunger 2 pulls downward, respectively, enabling the hydraulic dual-cylinder plunger pump 100 to perform work throughout its entire stroke. Please refer to... Figure 10 Curve 1 represents the motor power required for one revolution of a single-cylinder piston pump, while curve 2 represents the motor power required for one revolution of a hydraulic dual-cylinder piston pump 100. Comparing the impact of the single-cylinder piston pump and the hydraulic dual-cylinder piston pump 100 on the motor, under the same power requirement, the hydraulic dual-cylinder piston pump 100 requires less fluctuation in motor output power, thus enabling the hydraulic tool 1000 to operate more smoothly. Simultaneously, with each revolution of the motor, the hydraulic dual-cylinder piston pump 100 generates effective output in both the upward and downward strokes, with minimal fluctuation, reducing battery power consumption and improving battery life. Furthermore, the hydraulic dual-cylinder piston pump 100 eliminates the need for a return spring, thus eliminating spring-induced power loss and improving the utilization efficiency of motor output energy, further enhancing battery life.

[0056] The hydraulic dual-cylinder plunger pump 100 of the present invention forms a first working chamber 220 and a second working chamber 4, i.e., a double cylinder, between the plunger 2 and the cylinder body 200, making the hydraulic dual-cylinder plunger pump 100 a single-plunger double-cylinder structure. The first working chamber 220 and the second working chamber 4 are respectively connected to the oil inlet 230 and the oil outlet 240 of the piston chamber 210. A plunger check valve 3 is provided on the plunger 2 to connect the first working chamber 220 and the second working chamber 4. The plunger check valve 3 opens when the pressure in the first working chamber 220 is greater than the pressure in the second working chamber 4. Thus, the first working chamber 220 and the second working chamber 4 serve as the oil inlet chamber when the plunger 2 is pushed up and the oil inlet chamber when the plunger 2 is pulled down, respectively, realizing the full stroke work of the hydraulic dual-cylinder plunger pump 100, which can achieve the effects of smoothing alternating load, reducing vibration, and improving energy utilization efficiency.

[0057] As described above, the hydraulic dual-cylinder piston pump 100 may include a portion of the cylinder body 200. Optionally, please refer to [link to relevant documentation]. Figure 2 , Figure 4 and Figure 5 In this embodiment, a bushing 1 is provided inside the cylinder body 200. The bushing 1 is sleeved outside the piston part 27. The upper side of the bushing 1 and the upper end face of the piston part 27 cooperate with the piston cavity 210 to form a first working cavity 220. A second working cavity 4 is formed between the bushing 1 and the piston part 27.

[0058] Specifically, the bushing 1 is fixedly fitted inside the lower end of the piston cavity 210. The upper side of the bushing 1, the upper end face of the piston portion 27, and the inner wall of the piston cavity 210 form a first working cavity 220. A second working cavity 4 is formed between the inner circumferential side of the bushing 1 and the piston portion 27. The bushing 1 is fitted outside the piston portion 27 (i.e., the upper end of the plunger 2). Please refer to [reference needed]. Figure 5 When the plunger 2 is at its lowest point, the upper end face of the piston portion 27 is flush with or nearly flush with the upper side face of the bushing 1. (See also...) Figure 6 and Figure 8 As the plunger 2 slides upward, the upper end of the piston part 27 gradually enters the first working chamber 220, thereby making the cavity volume of the first working chamber 220 gradually smaller.

[0059] A second working chamber 4 is formed between the bushing 1 and the piston portion 27. Optionally, please refer to Figure 4 In this embodiment, the lower end face of the piston portion 27 is a first annular surface 22, and a second annular surface 12 facing the piston portion 27 is provided on the inner peripheral side of the bushing 1. The piston chamber 210 forms a second working chamber 4 between the second annular surface 12 and the first annular surface 22.

[0060] Specifically, as described above, the diameter of the piston portion 27 of the plunger 2 is larger than the diameter of the rod portion 28, causing the lower end face of the piston portion 27 to form a downward-facing first annular surface 22, thus forming the first annular surface 22 on the circumferential side of the plunger 2. The shape of the inner circumferential side of the bushing 1 is usually adapted to the shape of the circumferential side of the plunger 2, thus forming an upward-facing second annular surface 12 on the inner circumferential side of the bushing 1. The first annular surface 22 and the second annular surface 12 are vertically opposite each other, so that the first annular surface 22, the second annular surface 12, and the inner circumferential side of the bushing 1 located between the first annular surface 22 and the second annular surface 12 enclose and form the second working cavity 4.

[0061] When the plunger 2 is at its lowest point, the first annular surface 22 can abut against the second annular surface 12; alternatively, the first annular surface 22 can have a pre-existing gap with the second annular surface 12 in the vertical and upward directions. Alternatively, please refer to... Figures 5 to 8 In this embodiment, when the plunger 2 is at its lowest point, a gap is reserved between the first annular surface 22 and the second annular surface 12 in the vertical direction. As the plunger 2 slides upward, the gap between the first annular surface 22 and the second annular surface 12 gradually increases, thereby gradually increasing the cavity volume of the second working cavity 4. As the plunger 2 slides downward, the gap between the first annular surface 22 and the second annular surface 12 gradually decreases, thereby gradually decreasing the cavity volume of the second working cavity 4.

[0062] The second working chamber 4 connects to the oil outlet 240 of the cylinder block 200. Optionally, please refer to... Figure 2 and Figure 5 In this embodiment, a bushing oil passage 11 is provided through the bushing 1, connecting the oil outlet 240 and the second working chamber 4. The bushing oil passage 11 on the bushing 1 facilitates the connection between the second working chamber 4 and the oil outlet 240 of the cylinder block 200.

[0063] The specific configuration of the bushing oil passage 11 can be set according to the actual situation. Optionally, please refer to [link / reference needed]. Figure 3 , Figures 5 to 8 In this embodiment, the bushing oil passage 11 extends radially along the bushing 1 and is located above the second annular surface 12. This arrangement of the bushing oil passage 11 results in a relatively short oil path and relatively low fluid resistance.

[0064] Piston section 27 is provided with plunger oil passage 21 connecting the first working chamber 220 and the second working chamber 4. The specific arrangement of plunger oil passage 21 on piston section 27 can be set according to actual conditions. Optionally, please refer to Figure 3 In this embodiment, the plunger oil passage 21 penetrates the upper end face of the plunger 2 and the first annular surface 22.

[0065] Specifically, the upper end of the plunger oil passage 21 penetrates the upper end face of the plunger 2, and the lower end of the plunger oil passage 21 penetrates the lower end face of the plunger 2 (i.e., the first annular surface 22). This helps to make the oil passage of the plunger oil passage 21 shorter, so that the liquid resistance of the plunger oil passage 21 can be relatively small.

[0066] Further, please refer to Figure 3 In this embodiment, the plunger oil passage 21 includes an installation channel 23 and a connecting channel 24. The installation channel 23 is disposed on the upper end face of the piston part 27. One end of the installation channel 23 is opened on the upper side of the first annular surface 22. The plunger check valve 3 is disposed in the installation channel 23. One end of the connecting channel 24 penetrates the inner channel wall of the installation channel 23, and the other end of the connecting channel 24 penetrates the first annular surface 22. Multiple connecting channels 24 are provided at intervals along the circumference of the installation channel 23.

[0067] Specifically, the plunger oil passage 21 consists of an installation channel 23 and multiple connecting channels 24. The installation channel 23 is provided on the upper end face of the plunger 2 to facilitate the installation of the plunger check valve 3 in the plunger oil passage 21. The multiple connecting channels 24 facilitate the uniform flow of hydraulic oil in the first working chamber 220 into the second working chamber 4 through the multiple connecting channels 24.

[0068] The upper end of the connecting channel 24 penetrates the inner channel wall of the mounting channel 23, and the lower end of the connecting channel 24 penetrates the lower end face (i.e., the first annular surface 22) of the piston portion 27. The specific arrangement of the connecting channel 24 can be set according to actual conditions; optionally, please refer to [reference needed]. Figure 3In this embodiment, the connecting channel 24 is a straight hole extending along a straight line. The extending direction of the connecting channel 24 is gradually inclined from top to bottom away from the central axis of the plunger 2. For example, the upper end of the connecting channel 24 passes through the connection between the side wall and the bottom wall of the mounting channel 23, and the lower end of the connecting channel 24 passes through the connection between the first annular surface 22 and the peripheral side of the rod 28. By setting the connecting channel 24 in this way, the oil passage of the connecting channel 24 can be relatively short and the liquid resistance of the connecting channel 24 can be relatively small.

[0069] The plunger check valve 3 opens when the pressure in the first working chamber 220 is greater than the pressure in the second working chamber 4. The specific design of the plunger check valve 3 can be set according to actual conditions. Optionally, please refer to... Figure 2 and Figure 3 In this embodiment, the plunger check valve 3 includes a valve seat 31 and a valve ball 33. The valve seat 31 is disposed in the plunger oil passage 21, and the valve seat 31 is provided with an oil inlet channel 32 that connects the first working chamber 220 and the plunger oil passage 21. The valve ball 33 is located on the side of the oil inlet channel 32 away from the port of the first working chamber 220. When the plunger 2 slides downward, the valve ball 33 blocks the port of the oil inlet channel 32 away from the first working chamber 220, so that the plunger check valve 3 is closed. When the plunger 2 slides upward, the valve ball 33 separates from the valve seat 31 and opens the port of the oil inlet channel 32, so that the plunger check valve 3 is opened.

[0070] Specifically, the valve seat 31 is cylindrically shaped extending vertically, forming an oil inlet channel 32 on its inner side. The valve seat 31 is positioned at the opening of the mounting channel 23. The valve ball 33 is located below the valve seat 31 and within the mounting channel 23, with a diameter larger than the inner diameter of the valve seat 31. When the pressure in the first actuating chamber 220 is greater than the pressure in the second actuating chamber 4, the valve ball 33 moves downward under the pressure difference, separating from the valve seat 31. The valve ball 33 moves to its lowest point, opening the plunger check valve 3. When the plunger 2 moves downward, the valve ball 33 moves upward, reaching its highest point and blocking the lower end of the oil inlet channel 32, thus closing the plunger check valve 3.

[0071] Valve seat 31 can be fixed in the mounting channel 23 by means of thread fixing or interference fit, etc. Optionally, please refer to Figure 2 and Figure 3 In this embodiment, an annular limiting surface 25 is provided on the inner wall of the plunger oil passage 21, and the annular limiting surface 25 abuts against the side of the valve seat 31 away from the first working chamber 220.

[0072] Specifically, an upward-facing annular limiting surface 25 is provided on the inner groove side wall of the installation channel 23. The annular limiting surface 25 abuts against the upper side of the valve seat 31. In this way, the valve seat 31 can be installed and positioned in the installation channel 23 through the abutting cooperation between the valve seat 31 and the annular limiting surface 25.

[0073] Optionally, please refer to Figure 2 and Figure 3 In this embodiment, a first annular seal 26 is sleeved between the plunger 2 and the bushing 1, and the first annular seal 26 is located on the lower side of the second working cavity 4.

[0074] Specifically, a first annular mounting groove is provided on the peripheral side of the rod portion 28 of the plunger 2. The first annular mounting groove is located below the first annular surface 22 and the second annular surface 12. A first annular seal 26 is provided at the first annular mounting groove. Thus, by providing the first annular seal 26 between the plunger 2 and the bushing 1, the sealing between the plunger 2 and the bushing 1 can be guaranteed.

[0075] Optionally, please refer to Figure 1 , Figure 2 and Figure 5 In this embodiment, a second annular seal 13 is fitted between the bushing 1 and the inner wall of the piston chamber 210, and the second annular seal 13 is located on the lower side of the bushing oil passage 11.

[0076] Specifically, a second annular mounting groove is provided on the outer peripheral side of the bushing 1. The second annular mounting groove is located below the second annular surface 12 and the oil outlet 240. A second annular seal 13 is provided at the second annular mounting groove. Thus, by providing the second annular seal 13 between the bushing 1 and the inner wall of the piston chamber 210, the sealing between the bushing 1 and the inner wall of the piston chamber 210 can be guaranteed.

[0077] Optionally, please refer to Figures 5 to 8 In this embodiment, both the oil inlet 230 and the oil outlet 240 extend radially along the bushing 1, and the bushing oil passage 11, the oil inlet 230, and the oil outlet 240 extend in the same direction. This arrangement of the oil inlet 230 and the oil outlet 240 results in relatively short oil passages for the oil inlet 230 and the oil outlet 240, thus reducing the fluid resistance of the oil inlet 230 and the oil outlet 240.

[0078] Optionally, please refer to Figures 5 to 8 In this embodiment, the oil inlet 230 is located above the oil outlet 240, and the oil inlet 230 and the oil outlet 240 are located on both sides of the piston chamber 210 in the extending direction of the oil inlet 230.

[0079] Optionally, please refer to Figures 5 to 8In this embodiment, an oil suction check valve 250 is provided at the oil inlet 230. The oil suction check valve 250 is used to open when the pressure in the first working chamber 220 is less than the pressure in the oil tank 500 at the other end of the oil inlet 230. An oil outlet check valve 260 is provided at the oil outlet 240. The oil outlet check valve 260 is used to open when the pressure in the second working chamber 4 is greater than the pressure in the working cylinder 400 at the other end of the oil outlet 240.

[0080] Specifically, the piston chamber 210 is equipped with only two one-way valves: an oil suction one-way valve 250 and an oil discharge one-way valve 260. The oil suction one-way valve 250 and the oil discharge one-way valve 260 are connected to the first working chamber 220 and the second working chamber 4, respectively. The oil suction one-way valve 250 and the oil discharge one-way valve 260 are installed in opposite directions, forming the oil inlet and outlet of the cylinder body 200, respectively. Furthermore, an additional plunger one-way valve 3 is added to the plunger 2, allowing it to switch to a dual-cylinder configuration. This enables the first working chamber 220 and the second working chamber 4 to share a pair of oil inlet and outlet valves. This simplifies the structure of the hydraulic dual-cylinder plunger pump 100, resulting in a smaller footprint and meeting the requirements of lightweight and compact handheld hydraulic tools. Therefore, the hydraulic dual-cylinder plunger pump 100 is suitable for use with handheld hydraulic tools.

[0081] Optionally, please refer to Figures 5 to 8 In this embodiment, a filter 270 is provided at the suction check valve 250. In this way, the hydraulic oil entering the first working chamber 220 from the oil inlet 230 can be filtered by the filter 270.

[0082] Please see Figure 6 and Figure 7 When the plunger 2 moves upward, the valve ball 33 inside the plunger 2 moves downward under the action of the pressure difference, the cavity volume of the first working chamber 220 decreases (the hydraulic oil pressure in the first working chamber 220 increases), the suction check valve 250 closes based on the pressure difference, the discharge check valve 260 opens, and hydraulic oil is forced into the working cylinder 400, causing the piston rod in the working cylinder 400 to move. For example, Figure 7 The thick solid arrow indicates that the hydraulic oil flows through the following path: first working chamber 220 → plunger oil passage 21 → second working chamber 4 → oil inlet 230 → working cylinder 400.

[0083] Please see Figure 8 and Figure 9 When the plunger 2 moves downward, the cavity volume of the first working chamber 220 increases, and hydraulic oil from the oil tank 500 is drawn into the first working chamber 220 through the suction check valve 250 and the filter 270. For example... Figure 9As indicated by the thick solid arrow, the hydraulic oil flow path is: oil tank 500 → filter 270 → suction check valve 250 → first working chamber 220. Simultaneously, the valve ball 33 inside the plunger 2 moves upward to isolate the second working chamber 4 from the first working chamber 220, initiating compression of the second working chamber 4. This forces the hydraulic oil in the second working chamber 4 through the outlet check valve 260 into the working cylinder 400. The piston rod inside the working cylinder 400 continues to move forward, wherein, as... Figure 9 The dashed arrow indicates that the hydraulic oil flows through the second working chamber 4 → oil inlet 230 → working cylinder 400.

[0084] Compared with existing single-cylinder piston pumps, the hydraulic twin-cylinder piston pump 100 has the following advantages:

[0085] 1. The hydraulic double-cylinder piston pump 100 can achieve reciprocating motion by being driven by the crankshaft. A single-cylinder piston pump usually does work in only one stroke, while the hydraulic double-cylinder piston pump 100 does work in both reciprocating strokes, which makes higher efficiency utilization of the drive motor.

[0086] 2. Under the same output conditions, since the hydraulic double-cylinder plunger pump 100 does work in both reciprocating strokes, the structural size of the hydraulic double-cylinder plunger pump 100 can be made smaller.

[0087] 3. Under the same output conditions, since the hydraulic double-cylinder piston pump 100 can distribute the output across two reciprocating strokes, the impact on the drive motor is small, which can improve the service life of the drive motor. At the same time, the power requirement of the drive motor is small, and a smaller model of drive motor can be selected.

[0088] 4. Outlet flow pulsation (pulsation rate and pulsation amplitude) is the source of fluid noise vibration, and piston chamber pressure shock (pressure overshoot and pressure rise speed) is the source of structural noise vibration. Since the hydraulic double-cylinder piston pump 100 distributes the flow across two reciprocating strokes, the noise of the hydraulic double-cylinder piston pump 100 is relatively smaller than that of the single-cylinder piston pump.

[0089] The hydraulic dual-cylinder plunger pump 100 is a built-in dual-cylinder plunger pump. Compared with the existing external dual-cylinder plunger pumps, the hydraulic dual-cylinder plunger pump 100 has the following advantages:

[0090] 1. The hydraulic double-cylinder plunger pump 100 has a short oil circuit and relatively low fluid resistance;

[0091] 2. The hydraulic double-cylinder plunger pump 100 has low fluid resistance, low resistance work, that is, less wasted work, and high working efficiency.

[0092] 3. The hydraulic double-cylinder plunger pump 100 has a simple and compact structure and a small volume;

[0093] 4. Under the same efficiency conditions, the hydraulic double-cylinder piston pump 100 is lighter in weight, which can make the hydraulic tool 1000 lighter in weight and easier for the user to use;

[0094] 5. From a cost perspective, the hydraulic dual-cylinder piston pump 100 has fewer related parts, shorter oil circuits, and lower manufacturing costs;

[0095] 6. The hydraulic twin-cylinder plunger pump 100 requires fewer drive mechanisms (crankshafts). Two or more hydraulic twin-cylinder plunger pumps 100 can be arranged in the same volume, which improves the efficiency of use and reduces the impact on the drive mechanism.

[0096] The present invention also provides a hydraulic tool, which can be a hydraulic pliers, etc. Figures 4 to 8 A preferred embodiment of the hydraulic tool provided by the present invention is shown.

[0097] Please see Figures 4 to 8 In this embodiment, the hydraulic tool 1000 includes a hydraulic dual-cylinder plunger pump 100, a drive device 300, a working cylinder 400, and an oil tank 500. The oil tank 500 is connected to the oil inlet 230 of the hydraulic dual-cylinder plunger pump 100; the working cylinder 400 is connected to the oil outlet 240 of the hydraulic dual-cylinder plunger pump 100; the drive device 300 is connected to the end of the plunger 2 of the hydraulic dual-cylinder plunger pump 100 away from the piston portion 27, and is used to drive the piston portion 27 to slide within the piston chamber 210. Since the hydraulic dual-cylinder plunger pump 100 adopts the technical solution of the above embodiment, it has the beneficial effects brought about by the technical solution of the above embodiment.

[0098] Optionally, please refer to Figures 4 to 8 In this embodiment, the drive device 300 is connected to the lower end of the plunger 2 of the hydraulic double-cylinder plunger pump 100 through the eccentric wheel mechanism 310. The drive device 300 is used to drive the eccentric wheel mechanism 310 so as to drive the plunger 2 to move up and down through the eccentric wheel mechanism 310.

[0099] Specifically, the eccentric wheel mechanism 310 includes a push-pull rod 311 and an eccentric wheel 312. The push-pull rod 311 is located at the lower end of the plunger 2. The drive unit 300 is connected to the eccentric wheel 312 via a reduction gearbox 320. When the drive unit 300 is energized and rotates, it drives the eccentric wheel 312 to rotate via the reduction gearbox 320. The eccentric wheel 312 drives the push-pull rod 311, which in turn pushes the plunger 2 upward. When the drive unit 300 rotates to 180°, the plunger 2 reaches its highest point, the upward stroke of the plunger 2 ends, and the eccentric wheel 312 begins to pull the plunger 2 downward via the push-pull rod 311.

[0100] Optionally, please refer to Figures 4 to 8In this embodiment, the hydraulic tool 1000 is a handheld hydraulic tool. Since the hydraulic dual-cylinder plunger pump 100 occupies a small space, it can meet the requirements of light weight and small size for handheld hydraulic tools, thus making the hydraulic dual-cylinder plunger pump 100 suitable for handheld hydraulic tools.

[0101] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural transformations made using the contents of the specification and drawings of the present invention under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the scope of patent protection of the present invention.

Claims

1. A hydraulic dual-cylinder plunger pump, characterized in that, include: A cylinder body, wherein a piston chamber is formed within the cylinder body, and an oil inlet and an oil outlet communicating with the piston chamber are provided on the cylinder wall of the cylinder body; A plunger, one end of which is provided with a piston portion, which is slidably mounted in the piston chamber. The upper end face of the piston portion cooperates with the piston chamber to form a first working chamber, which is connected to the oil inlet. The lower end face of the piston portion cooperates with the piston chamber to form a second working chamber, which is connected to the oil outlet. A plunger oil passage is provided on the piston portion. A plunger check valve is disposed in the plunger oil passage and is used to open when the pressure in the first working chamber is greater than the pressure in the second working chamber, so as to connect the first working chamber and the second working chamber.

2. The hydraulic twin-cylinder plunger pump according to claim 1, characterized in that, A bushing is provided inside the cylinder body. The bushing is sleeved outside the piston part. The upper side of the bushing and the upper end face of the piston part cooperate to form the first working cavity of the piston cavity. The second working cavity is formed between the bushing and the piston part.

3. The hydraulic twin-cylinder plunger pump according to claim 2, characterized in that, The lower end face of the piston portion is a first annular surface, and the inner peripheral side of the bushing is provided with a second annular surface facing the piston portion. The piston cavity forms the second working cavity between the second annular surface and the first annular surface.

4. The hydraulic twin-cylinder plunger pump according to claim 3, characterized in that, The bushing is provided with a bushing oil passage that connects the oil outlet and the second working chamber.

5. The hydraulic twin-cylinder plunger pump according to claim 4, characterized in that, The bushing oil passage is arranged to extend radially along the bushing and is located on the upper side of the second annular surface.

6. The hydraulic twin-cylinder plunger pump according to claim 3, characterized in that, The plunger oil passage extends through the upper end face of the piston and the first annular surface.

7. The hydraulic twin-cylinder plunger pump according to claim 6, characterized in that, The plunger oil passage includes: The installation channel is located on the upper end face of the piston portion, and one end of the installation channel is opened on the upper side of the first annular surface. The plunger check valve is located inside the installation channel. A connecting channel, one end of which penetrates the inner wall of the mounting channel, and the other end of which penetrates the first annular surface, wherein multiple connecting channels are provided at intervals along the circumference of the mounting channel.

8. The hydraulic twin-cylinder plunger pump according to claim 1, characterized in that, The plunger check valve includes: A valve seat is disposed within the plunger oil passage, and the valve seat is provided with an oil inlet passage that connects the first working chamber and the plunger oil passage. A valve ball is located on the side of the oil inlet channel away from the first working chamber. When the plunger slides downward, the valve ball blocks the port of the oil inlet channel away from the first working chamber, thereby closing the plunger check valve. When the plunger slides upward, the valve ball separates from the valve seat and opens the port of the oil inlet channel, thereby opening the plunger check valve.

9. The hydraulic twin-cylinder plunger pump according to claim 1, characterized in that, An oil suction check valve is provided at the oil inlet. The oil suction check valve is used to open when the pressure in the first working chamber is less than the pressure in the oil tank at the other end of the oil inlet. An oil outlet check valve is provided at the oil outlet. The oil outlet check valve opens when the pressure in the second working chamber is greater than the pressure of the working cylinder at the other end of the oil outlet.

10. A hydraulic tool, characterized in that, include: The hydraulic twin-cylinder piston pump as described in any one of claims 1-9; The oil tank is connected to the oil inlet of the hydraulic dual-cylinder plunger pump; The working cylinder is connected to the oil outlet of the hydraulic dual-cylinder plunger pump; A drive unit is connected to the end of the plunger of the hydraulic twin-cylinder plunger pump away from the piston section, and is used to drive the piston section to slide within the piston chamber.

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