Hydraulic oil way system and electric hydraulic jack

Abstract

The hydraulic oil way system comprises an oil cylinder, an oil tank, a gear pump and a two-position four-way valve, the two-position four-way valve is provided with an oil port A, an oil port B, an oil port C and an oil port D. The oil tank is communicated with the oil inlet end of the gear pump through a first oil way. An oil inlet end of the gear pump is communicated with an oil port A of the two-position four-way valve, an oil outlet end of the gear pump is communicated with an oil port B of the two-position four-way valve, an oil port A of the two-position four-way valve is communicated with the oil cylinder, a first one-way valve is arranged on the first oil way, an oil inlet end of the gear pump is further communicated with an oil port C of the two-position four-way valve, and an oil port D of the two-position four-way valve is communicated with the oil tank. According to the hydraulic oil way system and the electric hydraulic jack, oil inlet and pressure relief can be achieved by controlling the gear pump, the control structure of the hydraulic oil way system is simple and easy to operate, the pressure relief speed of the hydraulic oil way system is controlled by the rotating speed of the gear pump, and the stability of pressure relief operation and the safety of operation are greatly guaranteed.

Description

Technical Field

[0001] The utility model relates to the technical field of hydraulic equipment, in particular to a hydraulic oil circuit system and an electric hydraulic jack. Background Art

[0002] As a kind of hydraulic equipment, a jack, like other hydraulic equipment, generally includes an oil cylinder, an oil tank and a pump body. During the working process, when it needs to rise, under the power of the pump body, the oil in the oil tank enters the oil cylinder, and the oil cylinder is pressurized to rise; when it needs to descend, the oil in the oil cylinder returns to the oil tank, and the oil cylinder is depressurized to descend. In order to realize the above pressurization and depressurization operations, in the existing hydraulic oil circuit system, as disclosed in the patent document with the Chinese patent application number 201920974528.7, a directional control valve is often arranged on the oil circuit. By changing the direction of the directional control valve, the oil circuit path is changed, and then the pressurization and depressurization operations are controlled. In this kind of hydraulic oil circuit system that controls the oil circuit path through a directional control valve, the pump body provides pressurization power, and the directional control valve changes the oil circuit path. The power control and the direction control are on two different components respectively, and the control is relatively scattered. It is impossible to achieve dual control of power and direction on the same component, and the whole control is relatively cumbersome. More importantly, in the existing hydraulic oil circuit system, during the depressurization process, the oil cylinder and the oil tank are directly connected, and the depressurization path does not pass through the pump body and is not controlled by other components such as the pump body. When a jack adopts the above hydraulic oil circuit system for depressurization, a situation of rapid and sudden drop will occur, bringing great danger to the use. Summary of the Utility Model

[0003] The first object of the utility model is a hydraulic oil circuit system.

[0004] The technical solution for realizing the object of the utility model is: a hydraulic oil circuit system, including an oil cylinder, an oil tank, a gear pump and a two-position four-way valve. The two-position four-way valve has an A oil port, a B oil port, a C oil port and a D oil port. When the B oil port admits oil, the two-position four-way valve is in the first working position. When the C oil port admits oil, the two-position four-way valve is in the second working position. In the first working position, the A oil port and the B oil port are connected, and the C oil port and the D oil port are not connected. In the second working position, the A oil port and the B oil port are connected, and the C oil port and the D oil port are connected. The oil tank is connected to the inlet end of the gear pump through a first oil circuit. The outlet end of the gear pump is connected to the B oil port of the two-position four-way valve through a second oil circuit. The A oil port of the two-position four-way valve is connected to the oil cylinder through a third oil circuit. A first check valve is arranged on the first oil circuit. The inlet end of the gear pump is also connected to the C oil port of the two-position four-way valve through a fourth oil circuit. The D oil port of the two-position four-way valve is connected to the oil tank through a fifth oil circuit.

[0005] Furthermore, it also includes a plunger pump, the oil inlet end of the plunger pump is connected to the oil outlet end of the gear pump through the sixth oil circuit, and the oil outlet end of the plunger pump is connected to the oil cylinder through the seventh oil circuit; the oil outlet end of the gear pump is also connected to the oil tank through the eighth oil circuit, and the eighth oil circuit is provided with a first pressure relief valve. The hydraulic oil circuit system of the utility model, through the setting of the plunger pump, enables the dual pump composed of the gear pump and the plunger pump to provide conditions for the variable and adjustable oil inlet flow rate. On this basis, combined with the use of the first pressure relief valve, the first pressure relief valve is used as an adjustment switch for the oil inlet flow rate, and the oil pressure in the oil cylinder is used as the adjustment basis. As the oil pressure in the oil cylinder changes, the oil inlet flow rate is automatically adjusted. For example, in the low-pressure state at the early stage of the electric hydraulic jack lifting, the first pressure relief valve is not opened, but closed, the gear pump and the plunger pump act as dual pumps, and the third oil circuit and the seventh oil circuit both supply oil with a large flow rate, that is, low-pressure and large-flow oil supply; as the lifting progresses, the pressure in the oil cylinder gradually increases, and in the later high-pressure state, the first pressure relief valve is opened under pressure, the eighth oil circuit is connected, and the oil pumped into the eighth oil circuit by the gear pump returns to the oil tank. At this time, only the seventh oil circuit supplies oil with a small flow rate, that is, high-pressure and small-flow oil supply. In the process of supplying oil to the oil cylinder, the hydraulic oil circuit system of the utility model can automatically adjust the oil flow rate into the oil cylinder as the pressure increases. During no-load and low-pressure periods, the oil is supplied with a large flow rate from both circuits for fast operation; during load and high-pressure periods, the oil is supplied with a small flow rate from a single circuit to reduce the moving speed, making the operation process smoother. For example, the hydraulic oil circuit system of the utility model is applied to the electric hydraulic jack, which can make the electric hydraulic jack rise quickly with large flow rate of oil in dual channels during no-load and low-pressure periods, and rise slowly with small flow rate of oil in single channel during loaded and high-pressure periods. The fast operation during the low-pressure period improves the operating efficiency; the stable operation during the high-pressure period ensures the operating safety. In other words, the hydraulic oil circuit system of the utility model takes into account both the operating efficiency and the operating safety, and is more convenient and easy to use.

[0006] Furthermore, the oil outlet of the plunger pump is connected to the B oil port of the two-position four-way valve through the seventh oil passage. Since the B oil port of the two-position four-way valve is also connected to the oil tank, the oil outlet of the plunger pump can also be connected to the oil tank after being connected to the B oil port of the two-position four-way valve through the seventh oil passage.

[0007] Furthermore, a second one-way valve is provided on the sixth oil circuit. The provision of the second one-way valve can ensure that the oil circuit on the sixth oil circuit can only be unidirectionally conducted from the gear pump to the plunger pump, thus facilitating the control of the system.

[0008] Furthermore, a third one-way valve is provided on the seventh oil circuit. The provision of the third one-way valve can ensure that the oil circuit on the seventh oil circuit can only be unidirectionally conducted from the plunger pump to the oil cylinder, thus facilitating the control of the system.

[0009] Furthermore, the oil outlet of the plunger pump is connected to the oil tank through the ninth oil circuit, and a second pressure relief valve is provided on the ninth oil circuit. During operation, after the oil cylinder runs to the maximum stroke, when the oil pressure in the oil cylinder is too high, the second pressure relief valve is opened under pressure, and the oil pumped by the plunger pump on the ninth oil circuit returns to the oil tank through the ninth oil circuit and no longer enters the oil cylinder. The second pressure relief valve plays a protective role to ensure safe operation.

[0010] Further, the two-position four-way valve includes a valve cavity and a valve core, the valve core is located in the valve cavity, and separates the valve cavity into a first cavity and a second cavity, the A oil port and the B oil port are each connected to the first cavity, the C oil port is connected to the second cavity, and the D oil port is located on the wall of the valve cavity, the valve core blocks the D oil port in the first working position, and the D oil port is located in the second cavity in the second working position. The A oil port and the B oil port located in the same first cavity are always connected; in the first working position, the valve core blocks the D oil port, and the C oil port and the D oil port are not connected; in the second working position, the D oil port is located in the second cavity and is connected to the C oil port located in the same second cavity.

[0011] Furthermore, the gear pump is installed on a rotatable main shaft, the main shaft is connected to a driving mechanism and is driven to rotate by the driving mechanism, a cam is also installed on the main shaft, the plunger pump is linked to the cam and can perform piston movement when pushed by the cam. During operation, the driving mechanism drives the gear pump and the plunger pump to work together, pumping the oil in the oil tank into the oil cylinder to achieve the lifting of the electric hydraulic jack. In the hydraulic oil circuit system of the utility model, the gear pump and the cam that pushes the plunger pump are installed on the same main shaft and are driven simultaneously by the driving mechanism. The coaxial installation driven by the same driving mechanism is not only more compact in structure but also lower in cost. Especially for smaller equipment, such as electric hydraulic jacks, its compact layout is more reasonable.

[0012] Furthermore, the driving mechanism is a motor.

[0013] Furthermore, the main shaft is an integral or split structure.

[0014] The second purpose of the utility model is to provide an electric hydraulic jack.

[0015] The technical solution for achieving the second purpose of the utility model is: an electric hydraulic jack, including the hydraulic oil circuit system described in the utility model.

[0016] The hydraulic oil circuit system and the electric hydraulic jack of the present utility model, on the basis of setting the gear pump, set the two-position four-way valve for controlling pressure relief on the oil circuit. The two-position four-way valve is hydraulically controllable. After combining the power source for controlling the two-position four-way valve to the gear pump, the gear pump not only serves as the oil inlet power of the oil circuit but also serves as the regulation power of the two-position four-way valve. The oil inlet power of the oil circuit and the control of pressure relief are concentrated on the same gear pump. When the gear pump rotates forward, the oil tank feeds oil into the oil cylinder for pressurization. When the gear pump rotates reversely, the oil cylinder returns oil to the oil tank for pressure relief. By controlling one gear pump, oil inlet and pressure relief can be achieved. The control structure of the hydraulic oil circuit system is simple and easy to operate. Moreover, when the gear pump controls the pressure relief of the hydraulic oil circuit system, the oil circuit passes through the gear pump, and the pressure relief speed of the hydraulic oil circuit system is controlled by the rotation speed of the gear pump, and the situation of rapid sudden drop of the oil pressure in the oil cylinder will not occur, greatly ensuring the stability of pressure relief operation and the safety of operation. Brief Description of the Drawings

[0017] Figure 1 is a schematic structural diagram of the hydraulic oil circuit system of the present utility model during oil inlet;

[0018] Figure 2 is a schematic structural diagram of the two-position four-way valve in the first working position during oil inlet of the hydraulic oil circuit system of the present utility model;

[0019] Figure 3 is a schematic structural diagram of the hydraulic oil circuit system of the present utility model during pressure relief;

[0020] Figure 4 is a schematic structural diagram of the two-position four-way valve in the second working position during pressure relief of the hydraulic oil circuit system of the present utility model;

[0021] Figure 5 is a schematic structural diagram of the installation of the gear pump and the plunger pump of the hydraulic oil circuit system of the present utility model. Detailed Embodiment

[0022] The following describes in detail the preferred embodiments of the hydraulic oil circuit system of the present utility model with reference to the drawings:

[0023] Such as Figure 1As shown, a hydraulic oil circuit system includes an oil cylinder 1, an oil tank 2, a gear pump 3 and a two-position four-way valve 4, wherein the two-position four-way valve 4 has an A oil port, a B oil port, a C oil port and a D oil port. When oil flows into the B oil port, the two-position four-way valve 4 is in a first working position, and when oil flows into the C oil port, the two-position four-way valve 4 is in a second working position. In the first working position, the A oil port and the B oil port are connected, and the C oil port and the D oil port are not connected. In the second working position, the A oil port and the B oil port are connected, and the C oil port and the D oil port are connected. The oil tank 2 is connected through the first oil circuit 101 It is connected to the oil inlet end 31 of the gear pump 3, the oil outlet end 32 of the gear pump 3 is connected to the B oil port of the two-position four-way valve 4 through the second oil circuit 102, the A oil port of the two-position four-way valve 4 is connected to the oil cylinder 1 through the third oil circuit 103, and the first one-way valve 201 is provided on the first oil circuit 101. The oil inlet end 31 of the gear pump 3 is also connected to the C oil port of the two-position four-way valve 4 through the fourth oil circuit 104, and the D oil port of the two-position four-way valve 4 is connected to the oil tank 2 through the fifth oil circuit 105.

[0024] In the hydraulic oil circuit system of the utility model, the first one-way valve 201 is a valve that conducts from the oil tank 2 to the gear pump 3 and blocks from the gear pump 3 to the oil tank 2 .

[0025] In the hydraulic oil circuit system of the utility model, when the oil tank 2 feeds oil into the oil cylinder 1 for pressurization, Figure 1 As shown, the gear pump 3 rotates forward. Under the power of the forward rotation of the gear pump 3, the oil in the oil tank 2 passes through the first oil circuit 101 and enters the gear pump 3 from the oil inlet end 31 of the gear pump 3; and then is pumped out from the oil outlet end 32 of the gear pump 3, passes through the second oil circuit 102, and enters the two-position four-way valve 4 from the B oil port of the two-position four-way valve 4. The two-position four-way valve 4 is located in the first working position, and the A oil port and the B oil port are guided. The oil in the two-position four-way valve 4 flows out from the A oil port and enters the oil cylinder 1 through the third oil circuit 103. The oil inlet pressurization path from the oil tank 2 to the oil cylinder 1 is: the oil tank 2-the first oil circuit 101-the oil inlet end 31 of the gear pump 3-the gear pump 3-the oil outlet end 32 of the gear pump 3-the second oil circuit 102-the B oil port of the two-position four-way valve 4-the two-position four-way valve 4-the A oil port of the two-position four-way valve 4-the third oil circuit 103-the oil cylinder 1.

[0026] In the hydraulic oil circuit system of the utility model, when the oil cylinder 1 discharges oil into the oil tank 2 to release pressure, Figure 3As shown, the gear pump 3 rotates in reverse. Under the driving force of the reverse rotation of the gear pump 3, the oil in the oil cylinder 1 passes through the third oil path 103 and enters the two-position four-way valve 4 from the A oil port; then it exits from the B oil port and enters the gear pump 3 through the second oil path 102. Due to the setting of the first check valve 201, the direction from the gear pump 3 to the fuel tank 2 on the first oil path 101 is blocked. The oil in the gear pump 3 can only enter the two-position four-way valve 4 from the C oil port through the fourth oil path 104. After the C oil port of the two-position four-way valve 4 is filled with oil, under the action of the oil pressure at the C oil port, the two-position four-way valve 4 is in the second working position, the A oil port and the B oil port are connected, and the C oil port and the D oil port are connected. The oil entering the two-position four-way valve 4 from the C oil port flows out from the D oil port and returns to the fuel tank 2 through the fifth oil path 105. The oil outlet and pressure relief path from the oil cylinder 1 to the fuel tank 2 is: the oil cylinder 1 - the third oil path 103 - the A oil port of the two-position four-way valve 4 - the two-position four-way valve 4 - the B oil port of the two-position four-way valve 4 - the second oil path 102 - the gear pump 3 - the fourth oil path 104 - the C oil port of the two-position four-way valve 4 - the two-position four-way valve 4 - the D oil port of the two-position four-way valve 4 - the fifth oil path 105 - the fuel tank 2.

[0027] In the hydraulic oil path system of the present utility model, on the basis of setting the gear pump 3, a two-position four-way valve 4 for controlling pressure relief is set on the oil path. The two-position four-way valve 4 is hydraulically controllable. After combining the power source for controlling the two-position four-way valve 4 with the gear pump 3, the gear pump 3 not only serves as the oil inlet power of the oil path but also serves as the regulation power of the two-position four-way valve 4. The oil inlet power of the oil path and the control of pressure relief are concentrated on the same gear pump 3. When the gear pump 3 rotates forward, the fuel tank 2 pressurizes and feeds oil into the oil cylinder 1. When the gear pump 3 rotates in reverse, the oil cylinder 1 returns oil to the fuel tank 2 for pressure relief. By controlling one gear pump 3, oil inlet and pressure relief can be achieved. The control structure of the hydraulic oil path system is simple and easy to operate. Moreover, when the gear pump 3 controls the pressure relief of the hydraulic oil path system, the oil path passes through the gear pump 3, and the pressure relief speed of the hydraulic oil path system is controlled by the rotation speed of the gear pump 3, and the situation of rapid sudden drop of the oil pressure in the oil cylinder 1 will not occur, which greatly guarantees the stability of pressure relief operation and the safety of operation.

[0028] Preferably, the hydraulic oil path system of the present utility model further includes a piston pump 5. The oil inlet end 51 of the piston pump 5 is connected to the oil outlet end 32 of the gear pump 3 through a sixth oil path 106, and the oil outlet end 52 of the piston pump 5 is connected to the oil cylinder 1 through a seventh oil path 107. The oil outlet end 32 of the gear pump 3 is connected to the fuel tank 2 through an eighth oil path 108, and a first pressure relief valve 301 is provided on the eighth oil path 108.

[0029] When the hydraulic oil circuit system of the utility model is working, the gear pump 3 and the plunger pump 5 work simultaneously. Specifically, under the pumping pressure of the gear pump 3, the oil in the oil tank 2 first enters the gear pump 3 through the first oil circuit 101, and then is pumped out through the oil outlet end 32 of the gear pump 3. At the early stage of oil inlet, the oil cylinder 1 is in a low-pressure state. The oil flowing out of the gear pump 3 enters the second oil circuit 102 in one way and enters the two-position four-way valve 4 from the B oil port. The two-position four-way valve 4 is in the first working position. In the first working position, the A oil port and the B oil port are connected, and the C oil port and the D oil port are not connected. The oil in the two-position four-way valve 4 is output from the A oil port and enters the oil cylinder 1 through the third oil circuit 103; the oil flowing out of the gear pump 3 enters the sixth oil circuit 106 in another way and is pumped into the oil cylinder 1 by the plunger pump 5 through the seventh oil circuit 107. The third oil circuit 103 and the seventh oil circuit 107 are dual-channel large-flow oil inlet. At the late stage of oil inlet, the oil cylinder 1 is in a high-pressure state.

[0030] Under the high pressure state at the late stage of lifting, the first pressure relief valve 301 is opened by pressure, the eighth oil circuit 108 is connected, and the oil flowing out of the gear pump 3 enters the eighth oil circuit 108 in one way and is directly pumped back to the oil tank 2 by the gear pump 3; the other way enters the sixth oil circuit 106 and is sequentially pumped into the seventh oil circuit 107 and the oil cylinder 1 by the plunger pump 5. The seventh oil circuit 107 is supplied with oil in a single way with a small flow rate.

[0031] The hydraulic oil circuit system of the utility model, through the setting of the plunger pump 5, enables the dual pump composed of the gear pump 3 and the plunger pump 5 to provide conditions for the variable and adjustable oil inlet flow rate. On this basis, combined with the use of the first pressure relief valve 301, the first pressure relief valve 301 is used as an adjustment switch for the oil inlet flow rate, and the oil pressure in the oil cylinder 1 is used as the adjustment basis. The oil inlet flow rate is automatically adjusted as the oil pressure in the oil cylinder 1 changes. For example, in the low-pressure state at the early stage of the lifting of the electric hydraulic jack, the first pressure relief valve 301 is not opened and is in a closed state. The gear pump 3 and the plunger pump 5 act as dual pumps, and the third oil circuit 103 and the seventh oil circuit 107 both supply oil with a large flow rate, that is, low-pressure and large-flow oil supply; as the lifting proceeds, the pressure in the oil cylinder 1 gradually increases. In the later high-pressure state, the first pressure relief valve 301 is pressurized to open, and the eighth oil circuit 108 is connected. The oil pumped into the eighth oil circuit 108 by the gear pump 3 returns to the oil tank 2. At this time, only the seventh oil circuit 107 supplies oil with a small flow rate, that is, high-pressure and small-flow oil supply.

[0032] For the hydraulic oil circuit system of the present utility model, during the process of feeding oil into the oil cylinder 1, as the pressure increases, the oil feeding flow rate into the oil cylinder 1 can be automatically adjusted. During the no-load and low-pressure periods, double-way large-flow oil feeding is carried out for rapid operation; during the load-bearing and high-pressure periods, single-way small-flow oil feeding is carried out to reduce the operating speed and make the operation process more stable. If the hydraulic oil circuit system of the present utility model is applied to an electric hydraulic jack, the electric hydraulic jack can have double-way large-flow oil feeding during the no-load and low-pressure periods for rapid rising; during the load-bearing and high-pressure periods, single-way small-flow oil feeding is carried out and the rising speed is slow. The rapid operation during the low-pressure period improves the operation efficiency; the stable operation during the high-pressure period ensures the operation safety. That is to say, the hydraulic oil circuit system of the present utility model takes into account both the operation efficiency and the operation safety, and is more convenient and easy to use.

[0033] For the hydraulic oil circuit system of the present utility model, since the B oil port of the two-position four-way valve 4 is communicated with the oil tank 2, therefore, after the oil outlet end 52 of the plunger pump 5 is communicated with the B oil port of the two-position four-way valve 4 through the seventh oil path 107, it can also be communicated with the oil tank 2.

[0034] For the hydraulic oil circuit system of the present utility model, preferably, a second one-way valve 202 is provided on the sixth oil path 106. The setting of the second one-way valve 202 can ensure that the oil path on the sixth oil path 106 can only be unidirectionally conducted from the gear pump 3 to the plunger pump 5, thus facilitating the control of the system.

[0035] For the hydraulic oil circuit system of the present utility model, preferably, a third one-way valve 203 is provided on the seventh oil path 107. The setting of the third one-way valve 203 can ensure that the oil path on the seventh oil path 107 can only be unidirectionally conducted from the plunger pump 5 to the oil cylinder 1, thus facilitating the control of the system.

[0036] For the hydraulic oil circuit system of the present utility model, preferably, the oil outlet end 52 of the plunger pump 5 is communicated with the oil tank 2 through the ninth oil path 109, and a second pressure relief valve 302 is provided on the ninth oil path 109. During the working process, after the oil cylinder 1 runs to the maximum stroke and the oil pressure in the oil cylinder 1 is too high, the second pressure relief valve 302 is pressured to open, and the oil pumped by the plunger pump 5 on the ninth oil path 109 returns to the oil tank 2 through the ninth oil path 109 and no longer enters the oil cylinder 1. The second pressure relief valve 302 plays a protective role to ensure the operation safety.

[0037] The hydraulic oil circuit system of the present utility model, the pressure threshold value at which the first pressure relief valve 301 opens is less than the pressure threshold value at which the second pressure relief valve 302 opens. That is to say, as the oil inlet and the oil pressure increase, after reaching the pressure threshold value at which the first pressure relief valve 301 opens, the first pressure relief valve 301 opens; continue to feed oil, the oil pressure continues to rise, and after reaching the pressure threshold value at which the second pressure relief valve 302 opens, the second pressure relief valve 302 opens.

[0038] The hydraulic oil circuit system of the present utility model, preferably, as Figure 2 and Figure 4 shown, the two-position four-way valve 4 includes a valve cavity 41 and a valve core 42. The valve core 42 is located in the valve cavity 41 and divides the valve cavity 41 into a first cavity 411 and a second cavity 412. The A oil port and the B oil port are each communicated with the first cavity 411, the C oil port is communicated with the second cavity 412, and the D oil port is located on the wall of the valve cavity 41. In the first working position, the valve core 42 blocks the D oil port, and in the second working position, the D oil port is located in the second cavity 412. The A oil port and the B oil port located in the same first cavity 411 are always conducted; in the first working position, the valve core 42 blocks the D oil port, and the C oil port and the D oil port are not conducted, as Figure 2 shown; in the second working position, the D oil port is located in the second cavity 412 and is conducted with the C oil port located in the same second cavity 412, as Figure 4 shown.

[0039] The hydraulic oil circuit system of the present utility model, preferably, as Figure 5 shown, the gear pump 3 is installed on a rotatably arranged main shaft 6. The main shaft 6 is in transmission connection with a driving mechanism 7 and can be driven by the driving mechanism 7 to rotate. A cam 50 is also installed on the main shaft 6. The plunger pump 5 is linked with the cam 50 and can be pushed by the cam 50 to perform a piston movement. During operation, the driving mechanism 7 drives to drive the gear pump 3 and the plunger pump 5 to act together, and pump the oil in the fuel tank 2 into the oil cylinder 1 to realize the lifting of the electric hydraulic jack. The gear pump 3 and the cam 50 that pushes the plunger pump 5 are installed on the same main shaft 6. Driven by the driving mechanism 7, the main shaft 6 rotates, driving the gear pump 3 to perform pumping pressure while also driving the cam 50 to rotate. The rotating cam 50 pushes the plunger pump 5, causing the plunger pump 5 to also perform pumping pressure action. That is to say, driven by the driving mechanism 7, the gear pump 3 and the plunger pump 5 can be driven to act together.

[0040] The hydraulic oil circuit system of the present utility model, the gear pump 3 and the cam 50 that drives the plunger pump 5 are installed on the same main shaft 6 and are driven simultaneously by the drive mechanism 7. The coaxial installation driven by the same drive mechanism 7 not only makes the structure more compact but also reduces the cost. Especially for small-sized equipment such as electric hydraulic jacks, its compact layout is more reasonable.

[0041] In the hydraulic oil circuit system of the present utility model, the drive mechanism 7 is an electric motor.

[0042] In the hydraulic oil circuit system of the present utility model, the main shaft 6 can be an integral structure or a split structure.

[0043] The present utility model also provides an electric hydraulic jack, which includes the hydraulic oil circuit system of the present utility model.

[0044] In the electric hydraulic jack of the present utility model, after all the power is concentrated on the gear pump 3, while achieving full electric operation, the control is more convenient.

[0045] In the hydraulic oil circuit system and the electric hydraulic jack of the present utility model, the gear pump 3 includes a meshing driving gear and a driven gear, wherein the driving gear is installed on the main shaft 6. The gear pump 3, the plunger pump 5, the first one-way valve 201, the second one-way valve 202, the third one-way valve 203, the first pressure relief valve 301 and the second pressure relief valve 302 are all conventional structures in the art. Therefore, no further elaboration will be made in this application.

[0046] For those of ordinary skill in the technical field to which the present utility model pertains, without departing from the concept of the present utility model, several simple deductions or substitutions can be made, and all should be regarded as belonging to the protection scope of the present utility model.

Claims

1. A hydraulic oil circuit system, characterized in that: The invention comprises an oil cylinder, an oil tank, a gear pump and a two-position four-way valve, wherein the two-position four-way valve has an A oil port, a B oil port, a C oil port and a D oil port. When oil is introduced into the B oil port, the two-position four-way valve is in a first working position, and when oil is introduced into the C oil port, the two-position four-way valve is in a second working position. In the first working position, the A oil port is connected to the B oil port, and the C oil port is not connected to the D oil port. In the second working position, the A oil port is connected to the B oil port, and the C oil port is connected to the D oil port. The oil tank is connected to the oil inlet end of the gear pump through a first oil circuit, and the oil outlet end of the gear pump is connected to the B oil port of the two-position four-way valve through a second oil circuit. The A oil port of the two-position four-way valve is connected to the oil cylinder through a third oil circuit. A first check valve is arranged on the first oil circuit. The oil inlet end of the gear pump is also connected to the C oil port of the two-position four-way valve through a fourth oil circuit. The oil port is communicated with the oil tank through a fifth oil passage.

2. The hydraulic oil circuit system according to claim 1, wherein: It also includes a plunger pump, the oil inlet end of the plunger pump is connected to the oil outlet end of the gear pump through the sixth oil circuit, and the oil outlet end of the plunger pump is connected to the oil cylinder through the seventh oil circuit; the oil outlet end of the gear pump is connected to the oil tank through the eighth oil circuit, and the eighth oil circuit is provided with a first pressure relief valve.

3. The hydraulic oil circuit system according to claim 2, wherein: The oil outlet end of the plunger pump is connected to the B oil port of the two-position four-way valve through the seventh oil passage.

4. The hydraulic oil circuit system according to claim 2, characterized in that: A second one-way valve is provided on the sixth oil circuit.

5. The hydraulic oil circuit system according to claim 2, characterized in that: A third one-way valve is provided on the seventh oil circuit.

6. The hydraulic oil circuit system according to claim 2, characterized in that: The oil outlet end of the plunger pump is connected to the oil tank through a ninth oil passage, and a second pressure relief valve is provided on the ninth oil passage.

7. The hydraulic oil circuit system according to claim 1, wherein: The two-position four-way valve includes a valve cavity and a valve core. The valve core is located in the valve cavity and separates the valve cavity into a first cavity and a second cavity. The A oil port and the B oil port are each connected to the first cavity, the C oil port is connected to the second cavity, and the D oil port is located on the wall of the valve cavity. In the first working position, the valve core blocks the D oil port, and in the second working position, the D oil port is located in the second cavity.

8. The hydraulic oil circuit system according to claim 2, characterized in that: The gear pump is installed on a rotatable main shaft, the main shaft is connected to a driving mechanism and is driven to rotate by the driving mechanism. A cam is also installed on the main shaft, and the plunger pump is linked to the cam and can perform piston movement driven by the cam.

9. The hydraulic oil circuit system according to claim 8, wherein: The driving mechanism is a motor.

10. An electric hydraulic jack, characterized in that: A hydraulic oil circuit system comprising any one of claims 1 to 9.

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