Electro-hydraulic tool

Abstract

The present application belongs to the technical field of electric tools, and particularly relates to an electric hydraulic tool. The electric hydraulic tool comprises a working component, a hydraulic cylinder, an oil storage component, a hydraulic pump and a control valve mechanism. The control valve mechanism is provided with an overflow valve and a pilot valve. The hydraulic cylinder is provided with a working oil cavity, an overflow valve cavity in which the overflow valve is installed, a pilot valve cavity in which the pilot valve is installed and an oil outlet channel connecting the working oil cavity and the pilot valve cavity. When the overflow valve is opened, the oil flows from the overflow valve cavity to the pilot valve cavity and opens the pilot valve, and the oil in the oil outlet channel flows to the oil bag from the pilot valve cavity. The present application returns the oil through the pilot valve, and the overflow valve mainly assists the pilot valve to open, reduces the return requirement, thereby reducing the volume of the overflow valve, facilitating the arrangement of the control valve mechanism in the limited space, and saving the cost.

Description

Technical Field

[0001] This invention belongs to the field of power tool technology, and specifically relates to an electric hydraulic tool. Background Technology

[0002] An electro-hydraulic tool is a tool that uses an electric power source and hydraulic fluid as a medium, driving a working head through a transmission mechanism to perform operations. In pipeline and power construction work, different working heads can be equipped to achieve different functions, such as electro-hydraulic tools, electro-pipe expanders, and electro-shearing tools.

[0003] The applicant disclosed an electro-hydraulic tool in Chinese invention CN103072124B, which internally includes a piston pump for driving the working head and a pressure relief valve for depressurization. As shown in the aforementioned prior patent, existing electro-hydraulic tools often use a single-piston structure for the piston pump, resulting in significant noise and vibration for the user, leading to a poor user experience.

[0004] In addition, miniaturization and weight reduction of electro-hydraulic tools are currently the development trend of this industry. Existing electro-hydraulic tools are generally large and heavy, and when depressurizing, they are often controlled by an internal relief valve (also known as a pressure relief valve) to achieve oil return. However, because the valve port of the relief valve is small, the oil return speed is very slow, resulting in low efficiency and a poor user experience. If the valve port cross-section is increased, a larger and stronger relief valve spring is required, which not only increases the cost but also occupies a large space, making it unsuitable for placement in small and lightweight hydraulic tools. Summary of the Invention

[0005] This invention provides an electro-hydraulic tool that can accelerate oil return by rationally arranging the control valve mechanism within a limited space.

[0006] The present invention adopts the following technical solution:

[0007] An electro-hydraulic tool, characterized by the following features: a working part; a hydraulic cylinder having a working oil chamber; an oil reservoir having oil; a hydraulic pump for pumping the oil from the oil reservoir into the working oil chamber; and a control valve mechanism for returning the oil from the working oil chamber to the oil reservoir. The control valve mechanism includes an overflow valve and a pilot valve. The hydraulic cylinder also includes: an overflow valve chamber containing the overflow valve; a pilot valve chamber containing the pilot valve; and an oil outlet passage connecting the working oil chamber and the pilot valve chamber. When the overflow valve is open, oil flows from the overflow valve chamber to the pilot valve chamber, opening the pilot valve. Oil in the oil outlet passage then flows from the pilot valve chamber to the oil reservoir.

[0008] The electric hydraulic tool proposed in this invention also has the following features, wherein the hydraulic cylinder is further provided with: an oil inlet channel leading to the working oil chamber; a first oil passage connecting the working oil chamber and the overflow valve chamber; a second oil passage connecting the overflow valve chamber and the pilot valve chamber; and a return oil passage for conveying oil from the pilot valve chamber into the oil storage component. When the overflow valve is opened, the oil in the first oil passage flows from the overflow valve through the second oil passage and then to the pilot valve, opening the pilot valve.

[0009] The electro-hydraulic tool proposed in this invention also has the following feature: the pilot valve comprises: a pilot valve body, installed in the pilot valve cavity, and having a pilot inlet, a pilot valve port, and a pilot outlet; oil from the outlet channel enters the pilot valve body through the pilot inlet; a pilot valve ball, used to block the pilot valve port; a pilot valve piston, movably disposed in the pilot valve body, one end acting on the pilot valve ball; and a pilot valve spring, acting on the end of the pilot valve ball away from the pilot valve piston; oil from the second oil passage pushes the pilot valve piston, and the pilot valve piston pushes open the pilot valve ball blocking the pilot valve port, opening the pilot valve port; oil from the pilot inlet flows out through the pilot valve port from the pilot outlet into the return channel.

[0010] The electro-hydraulic tool proposed in this invention also has the following feature: the relief valve comprises: a relief valve body, installed in the relief valve cavity and having an overflow outlet; a relief valve seat, installed on the relief valve body and having an overflow inlet and an overflow valve port; a relief valve needle, movably disposed in the relief valve body, one end of which is used to block the overflow valve port; and a relief valve spring, acting on the relief valve needle; oil from the first oil passage flows into the overflow inlet and pushes the relief valve needle to open the overflow valve port, and the oil flows out from the overflow outlet into the second oil passage through the overflow valve port.

[0011] The electro-hydraulic tool proposed in this invention also has the feature that the width of the pilot valve port is greater than the width of the overflow valve port.

[0012] The electro-hydraulic tool proposed in this invention also has the following features, wherein the hydraulic pump includes: a pump body having an oil inlet and a return port leading to the oil storage component; an inlet valve plate mounted on the pump body and having an inlet check valve and an inlet chamber; an outlet valve plate mounted on the pump body and having an outlet check valve and an outlet port leading to the working oil chamber; and a plunger assembly mounted on the inlet valve plate for controlling the opening and closing of the inlet check valve and the outlet check valve; an outlet chamber is provided between the inlet valve plate and the outlet valve plate, the outlet check valve is located between the inlet chamber and the outlet chamber, an oil inlet is provided on the side wall of the inlet chamber, and the inlet check valve is provided on one side of the oil inlet.

[0013] The electric hydraulic tool proposed in this invention also has the following features, wherein the hydraulic pump further includes: a pump shaft rotatably disposed inside the pump body; a bearing disposed between the inner wall of the pump body and the outer periphery of the pump shaft; a turntable sleeved on the pump shaft and having an inclined plate inclined to the axis of the pump shaft; and the plunger assembly includes: a plunger, one end of which abuts against the inclined plate and the other end of which is movably disposed in the oil inlet chamber; and a plunger spring sleeved on the outside of the plunger and acting on the end of the plunger near the inclined plate.

[0014] The electric hydraulic tool proposed in this invention also has the following features: a pump seat is provided in the pump body, a mounting boss is provided on the pump seat, one end of the plunger spring is sleeved on the outside of the mounting boss, and the other end acts on the plunger. An elongated hole for the plunger to pass through is opened in the middle of the mounting boss, and the elongated hole communicates with the oil inlet chamber. An oil passage hole communicating with the oil inlet is also opened on the pump seat.

[0015] The electro-hydraulic tool proposed in this invention also has the following feature: the pump shaft is provided with an inclined surface for mounting the turntable; the turntable is a flat needle roller bearing and has: a support plate abutting against the inclined surface; the inclined plate being arranged parallel to the support plate; and needle rollers being pressed between the support plate and the inclined plate. During the rotation of the turntable following the pump shaft, the inclined plate and one end of the plunger always remain in contact.

[0016] The electro-hydraulic tool proposed in this invention also has the following feature: it further includes a drive mechanism for driving the pump shaft to rotate. The drive mechanism has: a drive member, a planetary gearbox, and is installed at the output end of the drive member. One end of the pump shaft is installed on the planetary gearbox, and the other end is installed on the pump body through an oilless bearing. An oil seal is provided between the end of the pump shaft near the planetary gearbox and the inner wall of the pump body.

[0017] Invention Function and Effect

[0018] According to the present invention, the electro-hydraulic tool has a relief valve and a pilot valve in its control valve mechanism, which are respectively installed in the relief valve chamber and the pilot valve chamber in the hydraulic cylinder. Furthermore, an oil outlet channel is provided in the hydraulic cylinder to connect the working oil chamber and the pilot valve chamber. This allows the pilot valve to be opened by the oil flowing from the relief valve to the pilot valve during oil return. The oil in the outlet channel can then flow directly from the pilot valve to the oil reservoir for return. In other words, the present invention uses the pilot valve for oil return. The relief valve primarily assists in opening the pilot valve, reducing the return requirement and thus reducing the size of the relief valve. This facilitates the arrangement of the control valve mechanism within a limited space, resulting in a compact structure and cost savings. Attached Figure Description

[0019] Figure 1 This is a structural diagram of the electric hydraulic tool of the present invention.

[0020] Figure 2 This is a cross-sectional view of the electro-hydraulic tool of the present invention.

[0021] Figure 3 yes Figure 2 Cross-sectional view along the AA direction.

[0022] Figure 4 This is a cross-sectional view of the control valve mechanism of the present invention installed on the cylinder body.

[0023] Figure 5 This is a cross-sectional view of the pilot valve of the present invention installed on the cylinder body.

[0024] Figure 6 This is a cross-sectional view of the structure where the hydraulic pump of this invention is located.

[0025] Figure 7 yes Figure 6 A magnified view of section B.

[0026] Figure 8 This is an installation structure diagram of the plunger assembly of the present invention.

[0027] Figure 9 This is a schematic diagram showing the state of the oil outlet check valve and the oil inlet check valve of the present invention when they are open.

[0028] Figure 10 This is an exploded view of the pump base and oil inlet valve plate of the present invention.

[0029] Reference numerals: Electric hydraulic tool 100, working head 10, hydraulic cylinder 20, cylinder body 21, working oil chamber 22, working piston 221, rod 222, piston spring 223, oil inlet channel 23, relief valve chamber 24, relief valve outlet chamber 241, pilot valve chamber 25, pilot valve inlet chamber 251, pilot valve outlet chamber 252, oil outlet channel 26, first oil passage channel 27, second oil passage channel 28 8. Oil return channel 29. Oil bag 30. Hydraulic pump 40. Pump body 41. Oil inlet 411. Oil return hole 412. Pump base 42. Long hole 421. Mounting boss 422. Oil passage hole 423. Oil inlet valve plate 43. Oil inlet check valve 431. Oil inlet chamber 432. Oil inlet 433. Oil outlet valve plate 44. Oil outlet check valve 441. Oil outlet hole 442. Oil outlet chamber 443. Plunger assembly. Pump shaft 45. Mounting ramp 451, bearing 46, turntable 47, ramp 471, support plate 472, needle roller 473, control valve mechanism 50, pilot valve 51, pilot valve body 511, mounting cavity one 511a, mounting cavity two 511b, pilot valve ball 512, pilot valve piston 513, contact 5131, pilot valve spring 514, pilot valve spring seat 515, pilot inlet 516, pilot valve port 5 17. Pilot valve outlet 518, pilot valve plug 519, overflow valve 52, overflow valve body 521, overflow valve seat 522, overflow valve needle 523, overflow valve spring 524, overflow valve spring seat 525, overflow inlet 526, overflow valve port 527, overflow outlet 528, handle 529, drive mechanism 60, drive component 61, planetary gearbox 62, plug ball 71, plug block 72. Detailed Implementation

[0030] To make the technical means, creative features, objectives and effects of the present invention easy to understand, the electric hydraulic tool of the present invention will be specifically described below in conjunction with embodiments and accompanying drawings.

[0031] <Example>

[0032] Figure 1 This is a structural diagram of the electric hydraulic tool of the present invention.

[0033] Figure 2 This is a cross-sectional view of the electro-hydraulic tool of the present invention.

[0034] This embodiment proposes an electric hydraulic tool 100, such as... Figure 1 and Figure 2As shown, the system includes a working component (i.e., a working head 10), a hydraulic cylinder 20, an oil storage component (i.e., an oil bag 30), a hydraulic pump 40, a control valve mechanism 50, and a drive mechanism 60. The working head 10 can be a clamping head, crimping head, or expansion head, etc., used to work the workpiece. The hydraulic cylinder 20 acts on the working head 10 and drives it to work the workpiece. The oil bag 30 contains hydraulic fluid. The hydraulic pump 40 pumps hydraulic fluid from the oil bag 30 into the hydraulic cylinder 20. The control valve mechanism 50 returns hydraulic fluid from the hydraulic cylinder 20 back into the oil bag 30. The hydraulic cylinder 20 includes a cylinder body 21, and the hydraulic pump 40 includes a pump body 41. One end of the cylinder body 21 is connected to the pump body 41, and the other end is connected to the working head 10. The oil bag 30 is installed on the outside of the pump body 41. The control valve mechanism 50 is installed on the cylinder body 21, and the drive mechanism 60 is installed at one end of the pump body 41. The oil bag 30 is installed on the outer periphery of the pump body 41, so that the pump body is partially enclosed inside the oil bag, which facilitates the entry and exit of oil in the pump body 41.

[0035] <Control Valve Mechanism>

[0036] Figure 3 yes Figure 2 Cross-sectional view along the AA direction.

[0037] Figure 4 This is a cross-sectional view of the control valve mechanism of the present invention installed on the cylinder body.

[0038] Figure 5 This is a cross-sectional view of the pilot valve of the present invention installed on the cylinder body.

[0039] In this embodiment, as Figures 1-5 As shown, the control valve mechanism 50 has a pilot valve 51 and a relief valve 52 arranged side by side. The cylinder body 21 has a working oil chamber 22, an oil inlet channel 23, a relief valve chamber 24, a pilot valve chamber 25, an oil outlet channel 26, a first oil passage channel 27, a second oil passage channel 28, and a return oil channel 29. A working piston 221 is installed in the working oil chamber 22. A piston spring 223 and a rod 222 connected to the working head 10 are mounted on the working piston 221. The oil inlet channel 23 leads to the working oil chamber 22 and is used to transport oil from the oil bag 30 into the working oil chamber 22. After the oil enters the working oil chamber 22, it can push the working piston 221 to move towards the working head, thereby causing the working head to work. A relief valve 52 is installed in the relief valve chamber 24, and a pilot valve 51 is installed in the pilot valve chamber 25.

[0040] Oil outlet channel 26 and oil return channel 29 are connected to pilot valve chamber 25. First oil passage channel 27 and second oil passage channel 28 are connected to overflow valve chamber 24. Pilot valve chamber 25 and overflow valve chamber 24 are connected through second oil passage channel 28. That is, first oil passage channel 27 connects working oil chamber 22 and overflow valve chamber 24, second oil passage channel 28 connects overflow valve chamber 24 and pilot valve chamber 25, oil outlet channel 26 connects working oil chamber 22 and pilot valve chamber 25, and oil return channel 29 is used to transport oil from pilot valve chamber 25 back to oil bag 30.

[0041] The main workflow for the oil in the working oil chamber 22 to flow back into the oil bag 30 is as follows:

[0042] When the overflow valve 52 is opened, the oil in the first oil passage 27 flows from the overflow valve chamber 24 through the second oil passage 28 and then to the pilot valve chamber 25, opening the pilot valve 51 in the pilot valve chamber 25. The oil in the outlet passage 26 flows from the pilot valve chamber 25 to the return oil passage 29 and finally returns to the oil bag 30. That is, the oil in the working oil chamber 22 can open the pilot valve 51 through the transport of the first oil passage 27 and return oil through the outlet passage 26.

[0043] <Relief Valve>

[0044] The specific structure of the overflow valve 52 in this embodiment is as follows:

[0045] like Figure 4 As shown, the overflow valve 52 includes: an overflow valve body 521, an overflow valve seat 522, an overflow valve needle 523, an overflow valve spring 524, and an overflow valve spring seat 525. The overflow valve body 521 is installed in the overflow valve cavity 24 via a threaded connection. The overflow valve seat 522 is installed at one end of the overflow valve body 521 and has an overflow inlet 526 and an overflow valve port 527. The overflow inlet 526 is connected to the first oil passage 27. The overflow valve needle 523 is movably disposed within the overflow valve body 521, with one end used to block the overflow valve port 527 and the other end fitted with the overflow valve spring 524. The overflow valve spring seat 525 is adjustablely installed at the end of the overflow valve body 521 away from the overflow valve seat 522 via a thread. One end of the overflow valve spring 524 is placed within the overflow valve spring seat 525, and the other end acts on the overflow valve needle 523. The overflow valve body 521 has an overflow outlet 528 near the tip of the overflow valve needle 523, and an overflow valve outlet chamber 241 is formed between the end of the overflow valve body 521 near the tip of the overflow valve needle 523 and the inner wall of the overflow valve chamber 24. The overflow outlet 528 and the second oil passage 28 are both connected to the overflow valve outlet chamber 241.

[0046] The working process of the overflow valve 52 is as follows:

[0047] The oil from the first oil passage 27 first enters the overflow inlet 526 and pushes the overflow valve needle 523 to open the overflow valve port 527. The overflow valve needle 523 continues to move under the push of the oil, opening the overflow outlet 528. The oil flows out through the overflow outlet 528 into the overflow valve outlet chamber 241, and then enters the pilot valve chamber 25 through the second oil passage 28.

[0048] <Pilot Valve>

[0049] The specific structure of the pilot valve 51 in this embodiment is as follows:

[0050] like Figure 4 and Figure 5 As shown, the pilot valve 51 includes: a pilot valve body 511, a pilot valve ball 512, a pilot valve piston 513, a pilot valve spring 514, and a pilot valve spring seat 515. The pilot valve body 511 is installed in the pilot valve cavity 25, and a pilot valve port 517 is opened in the middle. The two sides of the pilot valve port 517 form a first mounting cavity 511a and a second mounting cavity 511b, respectively. The pilot valve spring 514 and the pilot valve ball 512 are arranged in the second mounting cavity 511b. Under the action of the pilot valve spring 514, the pilot valve ball 512 is blocked at the pilot valve port 517. A pilot valve piston 513 is slidably disposed within mounting cavity 511a. One end of the pilot valve piston 513 is formed with a contact 5131 that can extend into the pilot valve port 517. The contact 5131 can act on the pilot valve ball 512 to push the pilot valve ball 512 open the pilot valve port 517. A pilot valve spring seat 515 is inserted into the end of mounting cavity 511b. One end of the pilot valve spring 514 is inserted into the pilot valve spring seat 515, and the other end abuts against the end of the pilot valve ball 512 away from the pilot valve piston 513.

[0051] The pilot valve body 511 has sealing rings between the end containing mounting cavity one 511a and the inner wall of the pilot valve cavity 25, and between the end containing mounting cavity two 511b and the inner wall of the pilot valve cavity 25, thereby dividing the pilot valve cavity 25 into a pilot valve inlet chamber 251, a pilot valve outlet chamber 252, and an oil passage inlet chamber 253. The oil passage inlet chamber 253 is connected to the second oil passage 28, and a plug assembly is provided on the opposite side of the oil passage inlet chamber 253 to the second oil passage 28. The plug assembly consists of a plug ball 71 and a plug block 72. The pilot valve body 511 also has a pilot inlet port 516 and a pilot outlet port 518 on both sides of the pilot valve port 517. Figure 5As shown, the pilot valve inlet chamber 251 connects to the outlet channel 26 and the pilot inlet port 516, and the pilot valve outlet chamber 252 connects to the return channel 29 and the pilot outlet port 518. The pilot valve 51 also has a pilot valve plug 519 disposed outside the pilot valve body 511. The pilot valve plug 519 is installed at the opening of the pilot valve chamber 25 by means of a threaded connection, which facilitates disassembly, replacement and installation.

[0052] The working process of pilot valve 51 is as follows:

[0053] Oil from the oil outlet channel 26 first enters the pilot valve inlet chamber 251, and then enters the second installation chamber 511b through the pilot inlet port 516. Oil from the second oil passage channel 28 enters the oil passage inlet chamber 253 and pushes the pilot valve piston 513. The contact 5131 of the pilot valve piston 513 pushes open the pilot valve ball 512 blocking the pilot valve port 517, thereby opening the pilot valve port 517. After the pilot valve port 517 is opened, the oil in the second installation chamber 511b can enter the first installation chamber 511a through the pilot valve port 517, and then enter the pilot valve outlet chamber 252 through the pilot outlet port 518. Finally, it flows out into the oil bag 30 through the return oil passage 29.

[0054] In this embodiment, the width of the pilot valve port 517 is greater than the width of the overflow valve port 527, so the oil can return through the pilot valve port 517 at a faster speed, thus achieving rapid oil return.

[0055] Additionally, the relief valve 52 can also be called a pressure relief valve, pressure control valve, or safety valve. When the pressure in the working oil chamber 22 is too high, the oil can flow through the first oil passage 27 into the relief valve port 527, thereby opening the pilot valve 51 for oil return. This process can be called automatic pressure relief. For ease of use, a manual pressure relief function can be added, such as... Figure 4 As shown, the end of the overflow valve needle 523 away from the overflow valve port 527 extends out to the overflow valve spring seat 525 and is connected to the handle 529. The handle 529 is exposed on the outside of the cylinder body 21. The user can press or pull the handle 529 as needed to cause the overflow valve needle 523 to move to open the overflow valve port 527, thereby opening the pilot valve 51 to return oil and realize manual pressure relief.

[0056] Hydraulic pumps

[0057] Figure 6 This is a cross-sectional view of the structure where the hydraulic pump of this invention is located.

[0058] Figure 7 yes Figure 6 A magnified view of section B.

[0059] The hydraulic pump is mounted on the hydraulic tool and is used to control the flow of oil from the oil bag to the working oil chamber. The specific structure of the hydraulic pump 40 in this embodiment is as follows:

[0060] like Figure 6 As shown, the hydraulic pump 40 includes a pump body 41, a pump base 42, an inlet valve plate 43, an outlet valve plate 44, a plunger assembly, a pump shaft 45, a bearing 46, and a turntable 47. The plunger assembly has a plunger 48 and a plunger spring 49 sleeved on the outside of the plunger 48, with the plunger spring 49 acting on the end of the plunger 48 near the turntable 47. The pump body 41 has several inlet holes 411 leading to the oil bag 30 and return holes 412. The oil in the oil bag 30 can enter the pump body 41 through the inlet holes 411. The return holes 412 are located at the end near the cylinder 21, allowing the oil flowing out of the return channel 29 to flow back into the oil bag 30 through the return holes 412. Pump base 42, inlet valve plate 43, and outlet valve plate 44 are stacked and installed inside pump body 41. Inlet valve plate 43 is equipped with inlet check valve 431 and inlet chamber 432. Inlet port 433 is opened on the side wall of inlet chamber 432, and inlet check valve 431 is located on one side of inlet port 433. Outlet valve plate 44 is stacked on one side of inlet valve plate 43 and is equipped with outlet check valve 441 and outlet hole 442 leading to inlet channel 23 and working oil chamber 22. Outlet chamber 443 is located between inlet valve plate 43 and outlet valve plate 44, and outlet check valve 441 is located between inlet chamber 432 and outlet chamber 443. One end of plunger 48 extends into inlet chamber 432 and controls the opening and closing of inlet check valve 431 and outlet check valve 441 by changing the sealed volume within inlet chamber 432.

[0061] The pump shaft 45 is rotatably disposed inside the pump body 41, and a bearing 46 is provided between the inner wall of the pump body 41 and the outer circumference of the pump shaft 45. The bearing 46 can be a deep groove ball bearing or an angular contact ball bearing. The turntable 47 is sleeved on the pump shaft 45 and rotates together with the pump shaft 45. The turntable 47 has an inclined plate 471 that is inclined to the axis of the pump shaft 45. A plunger assembly is mounted on a pump base 42. The pump base 42 has an elongated hole 421 through which the plunger passes. This elongated hole 421 communicates with the oil inlet chamber 432. One end of the plunger 48 can extend through the elongated hole 421 into the oil inlet chamber 432 and move within the oil inlet chamber 432 to change the sealed volume within the oil inlet chamber 432, thereby controlling the opening and closing of the oil inlet check valve 431 and the oil outlet check valve 441. The other end of the plunger 48, under the action of the plunger spring 49, can always abut against one side surface of the inclined plate 471, and as the turntable 47 rotates with the pump shaft 45, one side surface of the inclined plate 471 and the other end of the plunger 48 always remain in contact. In this embodiment, as... Figure 7As shown, both the inlet check valve 431 and the outlet check valve 441 are formed by a combination of spring and valve plate. When the inlet check valve 431 and the outlet check valve 441 are closed, the valve plate is pressed against the corresponding valve port by the spring. Once the oil flows in, when the oil pressure is greater than the spring force, the valve plate can be pushed open to open the inlet check valve 431 and the outlet check valve 441.

[0062] Figure 8 This is an installation structure diagram of the plunger assembly of the present invention.

[0063] At least two plungers 48, plunger springs 49, inlet check valves 431, outlet check valves 441, and inlet chambers 432 are provided, and each plunger 48 and plunger spring 49 corresponds one-to-one with each inlet chamber 432. In this embodiment, as... Figure 8 As shown, four plungers 48 are provided, evenly arranged on one side of the inclined plate 471. The pump shaft 45 is provided with an inclined surface 451 for mounting the turntable 47. The turntable 47 is a flat needle roller bearing, having a support plate 472, the inclined plate 471, and a number of needle rollers 473. The support plate 472 abuts against the inclined surface 451, and the inclined plate 471 is arranged parallel to the support plate 472. The needle rollers 473 are pressed between the support plate 472 and the inclined plate 471. The ends of the four plungers 48 are all abutted against the inclined plate 471, and as the turntable 47 rotates with the pump shaft 45, the inclined plate 471 and one end of the plungers 48 remain in contact. Simultaneously, due to the inclined arrangement of the inclined plate 471, the four plungers 48 alternately move back and forth as the turntable 47 rotates with the pump shaft 45, causing the sealed volume within each oil inlet chamber 432 to change. Each set of control valves 431 for the inlet and outlet oil outlet also opens and closes accordingly. The use of flat needle roller bearings has the following advantages: low frictional resistance, low power consumption, and high mechanical efficiency; standardized dimensions, interchangeability, easy installation and disassembly, and convenient maintenance; compact structure, light weight, and reduced axial dimensions; high precision, high speed, low wear, and long service life; suitable for mass production, with stable and reliable quality and high production efficiency.

[0064] Figure 9 This is a schematic diagram showing the state of the oil outlet check valve and the oil inlet check valve of the present invention when they are open.

[0065] In such Figure 7 In the operating state shown, the upper plunger 48 moves towards the end of the inclined plate 471 under the force of the plunger spring 49, and the volume of the oil inlet chamber 432 where the plunger 48 is located increases, while the oil outlet check valve 441 and the oil inlet check valve 431 gradually close. Meanwhile, the lower plunger 48 moves towards the side of its oil inlet chamber 432 under the push of the inclined plate 471. (This can also be referenced...) Figure 9At this time, the volume of the oil inlet chamber 432 where the plunger 48 is located is decreasing. Under the push of the oil, the oil outlet check valve 441 and the oil inlet check valve 431 gradually open. The oil can enter the oil inlet chamber 432 through the oil inlet check valve 431, and enter the oil outlet chamber 443 through the oil outlet check valve 441, and then flow out from the oil outlet 442 into the oil inlet channel 23.

[0066] Figure 10 This is an exploded view of the pump base and oil inlet valve plate of the present invention.

[0067] like Figure 10 As shown, the pump base 42 has four mounting bosses 422 formed on it. An elongated hole 421 is formed in the center of each mounting boss 422. A plunger 48 is inserted into this elongated hole 421. One end of a plunger spring 49 is sleeved on the outer periphery of the mounting boss 422, and the other end acts on the other end of the plunger through a gasket, ensuring that the other end of the plunger 48 always abuts against the inclined plate 471. An oil passage hole 423 is also formed on one side of the bottom of the mounting bosses 422, leading to an oil inlet check valve 431. The oil inlet check valve 431 is located between the oil passage hole 423 and the oil inlet 433. Each mounting boss 422 corresponds to one oil inlet chamber 432, as shown below. Figure 9 As shown, when oil is introduced, the oil first enters through the oil passage 423, pushes open the oil inlet check valve 431, flows through the oil inlet check valve 431 and then flows into the oil inlet chamber 432 from the oil inlet port 433, and then pushes open the oil outlet check valve 441 to enter the oil outlet chamber 443.

[0068] <Drive mechanism>

[0069] like Figure 2 and Figure 6 As shown, the drive mechanism 60 drives the pump shaft 45 to rotate. The drive mechanism 60 has a drive component 61 and a planetary gearbox 62. The drive component 61 is a motor, and the planetary gearbox 62 is installed at the output end of the drive component 61. One end of the pump shaft 45 is installed on the planetary gearbox 62, and the other end is installed in the mounting hole in the middle of the pump seat 42 inside the pump body 41 through an oilless bearing 452. An oil seal 453 is provided between the end of the pump shaft 45 near the planetary gearbox 62 and the inner wall of the pump body 41 to cut off the internal space of the pump body 41 from the planetary gearbox 62, preventing oil from flowing into the planetary gearbox 62 and causing oil leakage. The use of an oilless bearing 452 to connect the pump shaft 45 and the pump seat 42 makes the structure more compact. The planetary gearbox 62 uses single-stage or multi-stage speed, which effectively increases the speed of the pump shaft, making the operation smoother, reducing impact, and extending the service life of components.

[0070] The working principle of this embodiment is as follows:

[0071] Oil intake process:

[0072] When the motor starts, it drives the pump shaft 45 to rotate. The inclined plate 471 rotates with the pump shaft 45, thereby driving the plunger 48 to move and changing the volume in the oil inlet chamber 432. When the plunger 48 moves towards one side of the oil inlet chamber 432 under the push of the inclined plate 471, the volume of the oil inlet chamber 432 where the plunger 48 is located gradually decreases. The oil enters from the oil passage 423, pushes open the oil inlet check valve 431, and enters the oil inlet chamber 432 through the oil inlet port 433. Then, it pushes open the oil outlet check valve 441 and enters the oil outlet chamber 443. It flows out from the oil outlet 442 into the oil inlet channel 23 and finally enters the working oil chamber 22. After the oil enters the working oil chamber 22, it can push the working piston 221 to move towards the working head, so as to make the working head work.

[0073] Automatic oil return process:

[0074] When the oil pressure in the working oil chamber 22 reaches the set value, the automatic oil return process is activated. The oil in the working chamber 22 enters the first oil passage 27 and the oil outlet 26 respectively. The oil in the first oil passage 27 can open the overflow valve 52. The oil flows through the second oil passage 28 and then flows to the pilot valve 51, opening the pilot valve 51. Once the pilot valve 51 is opened, the oil in the oil outlet 26 can flow from the pilot valve 51 to the oil return passage 29, and then flow back to the oil bag 30 through the oil return hole 412 on the pump body 41 to complete the automatic oil return process.

[0075] Manual return oil process:

[0076] During operation, the user can initiate the manual oil return process as needed. The oil in the working chamber 22 enters the first oil passage 27 and the oil outlet 26 respectively. The user can manually press or pull the handle 529 to directly open the overflow valve 52. The oil in the first oil passage 27 flows through the overflow valve 52, through the second oil passage 28, and then to the pilot valve 51, opening the pilot valve 51. Once the pilot valve 51 is opened, the oil in the oil outlet 26 can flow from the pilot valve 51 to the oil return passage 29, and then flow back to the oil bag 30 through the oil return hole 412 on the pump body 41 to complete the manual oil return process.

[0077] The effects of the above embodiments are as follows:

[0078] The above embodiment utilizes a pilot valve for oil return, while the relief valve primarily functions to open the pilot valve. This design allows for efficient placement within a limited space, and the flow rate at the valve port is faster than that of the relief valve, enabling rapid oil return. Furthermore, both the pilot valve and the relief valve are installed using threaded connections for easy disassembly, replacement, and installation. Because the control valve mechanism has an overflow valve and a pilot valve, which are respectively installed in the overflow valve chamber and the pilot valve chamber in the cylinder body, and an oil outlet channel is also provided in the cylinder body to connect the working oil chamber and the pilot valve chamber, when the tool returns oil, the oil flowing from the overflow valve to the pilot valve opens the pilot valve. Then, the oil in the oil outlet channel can flow directly from the pilot valve to the oil bag for return. That is, the present invention uses the pilot valve to achieve oil return, which is fast and efficient. The overflow valve mainly assists the pilot valve in opening, reducing the return requirements, thereby reducing the size of the overflow valve and facilitating the arrangement of the control valve mechanism in a limited space. The structure is compact and cost-effective.

[0079] The above embodiment uses a multi-plunger oil pump body, and uses an inclined plate to drive the reciprocating motion of multiple plungers, which can reduce noise and vibration during use and improve the user experience.

[0080] In the existing technology, the oil inlet chamber and the oil outlet chamber are respectively located at both ends of the plunger mounting chamber. Furthermore, the oil inlet chamber and the oil outlet chamber are each connected to the plunger mounting chamber by a separate oil inlet channel and an oil outlet channel. The oil needs to pass through the oil inlet channel, the plunger mounting chamber, and the oil outlet channel after the oil inlet check valve is opened before it can reach the oil outlet check valve and open. The entire oil circuit is relatively long and inefficient. Moreover, a long oil circuit will lead to an increase in the size and weight of the entire pump body, which is not conducive to the miniaturization and lightweight development of hydraulic tools. In the above embodiment, the inlet valve plate is equipped with an inlet check valve and an inlet chamber, while the outlet valve plate is equipped with an outlet check valve and an outlet hole leading to the working oil chamber. The inlet and outlet valve plates are stacked together, placing the inlet and outlet check valves near the inlet chamber, very close to each other. Simultaneously, one end of the plunger can extend into the inlet chamber and control the opening and closing of the inlet and outlet check valves by changing the sealed volume within the chamber. During operation, after the inlet check valve is opened, oil can quickly enter the inlet chamber, immediately opening the outlet check valve to supply oil. This results in high oil flow efficiency and a compact structure. In other words, the inlet and outlet check valves are directly positioned near the inlet chamber, resulting in high volumetric efficiency, rapid oil supply, improved oil delivery efficiency, and enhanced user experience.

[0081] The above embodiments are merely illustrative of specific implementations of the present invention, and the present invention is not limited to the scope of the description of the above embodiments. For example, in the above embodiments, the pump body 41 and the pump base 42 are separate structures; in actual situations, they can also be integrally formed structures.

Claims

1. An electric hydraulic tool, characterized in that, include: Working parts; A hydraulic cylinder, which has a working oil chamber inside; An oil storage component containing oil; A hydraulic pump is used to pump the oil from the oil reservoir into the working oil chamber; A control valve mechanism is used to return the oil from the working oil chamber back to the oil storage component; The control valve mechanism includes a relief valve and a pilot valve. The hydraulic cylinder is also equipped with: An overflow valve chamber, in which the overflow valve is installed; Pilot valve chamber, in which the pilot valve is installed; An oil outlet channel connects the working oil chamber and the pilot valve chamber; The overflow valve has an overflow valve port, the pilot valve has a pilot valve port, and the width of the pilot valve port is greater than the width of the overflow valve port. When the overflow valve port of the overflow valve is opened, the oil flows from the overflow valve chamber to the pilot valve chamber and opens the pilot valve port of the pilot valve. The oil in the oil outlet channel flows from the pilot valve chamber to the oil storage component.

2. The electro-hydraulic tool according to claim 1, Its features are, in, The hydraulic cylinder is also equipped with: An oil inlet channel leads to the working oil chamber; The first oil passage connects the working oil chamber and the overflow valve chamber; The second oil passage connects the overflow valve chamber and the pilot valve chamber; as well as The return oil passage is used to transport oil from the pilot valve chamber into the oil storage component.

3. The electro-hydraulic tool according to claim 2, Its features are, The pilot valve has the following features: The pilot valve body is installed in the pilot valve cavity and has a pilot oil inlet, a pilot valve port and a pilot oil outlet. Oil from the oil outlet channel enters the pilot valve body through the pilot oil inlet. A pilot valve ball is used to plug the pilot valve port. The pilot valve piston is movably disposed within the pilot valve body, with one end acting on the pilot valve ball; and The pilot valve spring acts on the end of the pilot valve ball that is away from the pilot valve piston; The oil from the second oil passage pushes the pilot valve piston, which in turn pushes open the pilot valve ball blocking the pilot valve port, allowing the oil from the pilot inlet to flow out through the pilot outlet into the return oil passage.

4. The electro-hydraulic tool according to claim 3, characterized in that, in, The overflow valve has: An overflow valve body is installed inside the overflow valve cavity and has an overflow outlet. An overflow valve seat is installed on the overflow valve body and has an overflow inlet and an overflow valve port. An overflow valve needle is movably disposed within the overflow valve body, with one end used to plug the overflow valve port; and The relief valve spring acts on the relief valve needle.

5. The electro-hydraulic tool according to claim 1, Its features are, The hydraulic pump includes: The pump body has an oil inlet and an oil return port leading to the oil storage component; An oil inlet valve plate is installed on the pump body and is equipped with an oil inlet check valve and an oil inlet chamber; An oil outlet valve plate, mounted on the pump body, is equipped with an oil outlet check valve and an oil outlet port leading to the working oil chamber; and A plunger assembly, mounted on the inlet valve plate, is used to control the opening and closing of the inlet check valve and the outlet check valve; An oil outlet chamber is provided between the oil inlet valve plate and the oil outlet valve plate. An oil outlet check valve is provided between the oil inlet chamber and the oil outlet chamber. An oil inlet is provided on the side wall of the oil inlet chamber, and the oil inlet check valve is provided on one side of the oil inlet.

6. The electro-hydraulic tool according to claim 5, characterized in that, in, The hydraulic pump also includes: The pump shaft is rotatably mounted inside the pump body. The bearing is disposed between the inner wall of the pump body and the outer periphery of the pump shaft. A turntable, fitted onto the pump shaft and having an inclined plate that is inclined to the axis of the pump shaft. The plunger assembly includes: The plunger has one end abutting against the inclined plate, and the other end movably positioned within the oil inlet chamber. A plunger spring is sleeved on the outside of the plunger and acts on the end of the plunger near the inclined plate.

7. The electro-hydraulic tool according to claim 6, characterized in that, in, The pump body is also provided with a pump seat, and the pump seat is provided with a mounting boss. One end of the plunger spring is sleeved on the outside of the mounting boss, and the other end acts on the plunger. The mounting boss has an elongated hole in the middle for the plunger to pass through, and the elongated hole communicates with the oil inlet chamber. The pump seat is also provided with an oil passage hole that communicates with the oil inlet.

8. The electro-hydraulic tool according to claim 6, characterized in that, in, The pump shaft is provided with a mounting ramp for mounting the turntable. The turntable is a flat needle roller bearing, having the following characteristics: The support plate rests against the mounting slope. The inclined plate is arranged parallel to the support plate. Needle rollers are pressed between the support plate and the inclined plate. As the turntable rotates following the pump shaft, the inclined plate remains in contact with one end of the plunger.

9. The electro-hydraulic tool according to claim 6, characterized in that, It also includes a drive mechanism for driving the pump shaft to rotate, the drive mechanism having: Drive components, The planetary gearbox is installed at the output end of the drive unit. One end of the pump shaft is mounted on the planetary gearbox, and the other end is mounted on the pump body via an oilless bearing. An oil seal is provided between the end of the pump shaft near the planetary gearbox and the inner wall of the pump body.

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