Open-closed hybrid hydraulic system

Abstract

The utility model discloses an open-closed hybrid hydraulic system which comprises a driving pump and a driven piece, and hydraulic cavities of the driving pump and the driven piece are communicated in a circulating mode to form a closed loop. The external oil tank can be communicated with the hydraulic cavity of the driven part through a valve block to form an open loop; a part of the pipeline of the closed loop leads into an internal hole channel of the valve block, so that the valve block can switch the conduction relation between the driving pump and the driven part and between the external oil tank and the driven part; the valve block comprises a pressure control oil return hole channel, conduction can be controlled according to the pressure difference of an inlet port and an outlet port of a hydraulic cavity of the driven part, and the closed loop is connected to the external oil tank through the pressure control oil return hole channel, so that part of return oil of the closed loop is connected to the external oil tank. According to the hydraulic system, energy loss can be effectively reduced during continuous high-power driving, and meanwhile the service life of the whole hydraulic system is prolonged.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic system technology, and in particular to an open-closed hybrid hydraulic system. Background Technology

[0002] Hydraulic systems, as common drive systems, typically employ an open structure. This allows impurities within the hydraulic system to be carried into the oil tank with the return oil. By adding filters, impurities from the tank are prevented from re-entering the hydraulic system. The impurities collected in the tank can be centrally filtered, which helps extend the lifespan of the hydraulic system. However, this also results in significant energy loss during hydraulic oil transmission. Consequently, to ensure higher output power, a greater hydraulic driving force is required, leading to increased energy consumption. Closed-loop hydraulic systems effectively solve the energy loss problem, but their drawback lies in the fact that, with a fixed amount of oil continuously circulating, small particles generated due to wear accumulate over time, significantly impacting the lifespan of the hydraulic system. Summary of the Invention

[0003] Purpose of the invention: In order to overcome the shortcomings of the existing technology, this utility model provides an open-closed hybrid hydraulic system that can effectively reduce energy loss and extend the service life of the entire hydraulic system when driven by continuous high power.

[0004] Technical solution: To achieve the above objectives, this utility model provides an open-closed hybrid hydraulic system, including a drive pump and a driven component, with their hydraulic chambers circulating and connected to form a closed loop; it also includes an external oil tank, which can be connected to the hydraulic chamber of the driven component through a valve block to form an open loop.

[0005] A portion of the closed-loop pipeline references the internal channels of the valve block, enabling the valve block to switch the connection between the drive pump, the external oil tank, and the driven component.

[0006] The valve block includes a pressure-controlled return oil channel, which can control the conduction according to the pressure difference between the inlet and outlet ports of the hydraulic chamber of the driven component. The closed circuit is connected to the external oil tank through the pressure-controlled return oil channel, so that the return oil of the closed circuit is connected to the external oil tank.

[0007] Furthermore, the closed circuit located inside the valve block includes an oil supply channel and an oil return channel. The inlet end of the pressure-controlled oil return channel is connected to the oil supply channel and the oil return channel respectively through two branch channels, and both branch channels are equipped with hydraulically driven valves.

[0008] Furthermore, the valve block is provided with an energy storage channel, the oil inlet end of which is connected to the external oil tank, and the oil outlet end is connected to the oil supply channel and the oil return channel respectively through two branch channels.

[0009] Furthermore, the external oil tank is connected to the drive pump via a replenishment oil pipeline. The oil outlet of the replenishment oil pipeline is connected to the two ports of the hydraulic chamber of the drive pump via two branch pipes, and each branch pipe is equipped with a hydraulic check valve.

[0010] Furthermore, the inlet ends of both the energy storage channel and the oil replenishment pipeline are connected to the external oil tank via an oil replenishment pump.

[0011] Furthermore, a hydraulic check valve is connected in series in the main channel of the energy storage channel, and two hydraulic check valves are connected to the oil supply channel and the oil return channel respectively at its oil outlet end, forming an energy storage section between the three hydraulic check valves.

[0012] Furthermore, the valve block includes a four-way switching valve, one set of which has an inlet / outlet port connected to an open oil supply pipeline and the oil supply channel, and another set of which has an inlet / outlet port connected to the return oil channel and the open return oil pipeline. The inlet end of the open oil supply pipeline and the outlet end of the open return oil pipeline are both connected to the external oil tank.

[0013] Furthermore, the oil supply channel is connected in series with a hydraulic shut-off valve, and the valve block includes a three-way shut-off control valve, whose three ends are respectively connected to the open oil supply line, the open oil return line and the hydraulic drive interface of the hydraulic shut-off valve, which can switch the conduction relationship between the open oil supply line, the open oil return line and the hydraulic drive interface of the hydraulic shut-off valve.

[0014] Beneficial effects: This utility model discloses an open-closed hybrid hydraulic system that can switch between closed-loop drive and open-loop drive modes to periodically clean up the small metal particles accumulated in the closed-loop drive, avoiding increased wear and reduced service life of the hydraulic system; during the closed-loop drive process, it can replace some of the high-temperature oil containing small particles in the closed loop with cold oil through continuous oil changing, which can effectively reduce the accumulation rate of small particles, extend the duration of a single closed-loop drive, reduce the number of open-loop drive switching, ensure stable drive with high flow and low loss, and solve the problem of oil pressure fluctuation that may be caused by oil changing. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the system structure of an embodiment of an open-closed hybrid hydraulic system according to this solution. Detailed Implementation

[0016] The present invention will be further described below with reference to the accompanying drawings.

[0017] As attached Figure 1The aforementioned open-closed hybrid hydraulic system includes a drive pump 1 and a driven component 2, whose hydraulic chambers are circulated and connected to form a closed loop. It also includes an external oil tank 4, which can be connected to the hydraulic chamber of the driven component 2 via a valve block 3 to form an open loop. Part of the closed loop's piping utilizes internal channels of the valve block 3, allowing the valve block 3 to switch the connection between the drive pump 1, the external oil tank 4, and the driven component 2. This solution connects the drive pump 1, the driven component 2, and the external oil tank 4 through internal channels of the valve block 3 to form an open-closed hybrid hydraulic system, capable of providing power to the driven component 2 in both open and closed hydraulic supply states. It is suitable for applications requiring a continuous and significant driving force for the driven component over a long period, such as the shaft drive of a crusher. This solution allows for closed-loop drive as the normal driving mode, continuously providing significant torque to the shaft and reducing energy loss during hydraulic transmission through components such as filters. Building upon this, it can periodically and proactively switch to open-loop drive mode. During this period, the closed loop can be cleaned and maintained, compensating for the drawbacks of prolonged closed-loop drive and preventing excessive accumulation of metal particles in the circulating oil, which could cause significant damage to the drive pump and driven components. This effectively reduces energy consumption while extending the service life of the entire hydraulic system.

[0018] The valve block 3 includes a pressure-controlled return oil channel, which can control the flow based on the pressure difference between the inlet and outlet ports of the hydraulic chamber of the driven component 2. The closed loop is connected to the external oil tank 4 through the pressure-controlled return oil channel, so that the return oil of the closed loop is connected to the external oil tank 4. The portion of the closed loop located inside the valve block 3 includes an oil supply channel 12 and an oil return channel 21. The inlet end of the pressure-controlled return oil channel is connected to the oil supply channel 12 and the oil return channel 21 respectively through two branch channels, and each branch channel is equipped with a hydraulic drive valve 5. The two hydraulic control interfaces of the hydraulic drive valve 5 are respectively connected to the inlet and outlet ports of the hydraulic chamber of the driven component 2.

[0019] Taking the motor as an example, the opening state of the hydraulic drive valve 5 is controlled by the pressure difference between the inlet and outlet oil of the motor. For example, a shuttle valve can be used. Due to the continuous existence of the pressure difference during operation, the shuttle valve always remains open. This ensures that most of the oil circulates in the closed loop, and a small portion of the oil returns to the external oil tank. Correspondingly, a portion of cold oil is drawn from the external oil tank to replenish the drive pump. This maintains the safe and stable operation of the closed loop and can also carry out some small metal particles to a certain extent, effectively slowing down the accumulation rate of metal particles in the circulating oil.

[0020] An additional proportional valve can be connected in series on the branch channel where the hydraulic drive valve 5 is located. A hydraulic sensor is installed at the inlet and outlet ports of the hydraulic chamber of the driven component 2 to control the opening of the proportional valve according to the pressure difference between the inlet and outlet ports of the hydraulic chamber of the driven component 2. Thus, when the hydraulic drive valve 5 is connected to the external oil tank, the oil supply of the closed circuit can be continuously adjusted according to the pressure difference change. This allows the pressure-controlled return oil channel to not only continuously supply oil to the closed circuit when there is a pressure difference, but also to adjust the oil supply according to the pressure difference change. Preferably, the opening of the proportional valve is increased when the pressure difference increases.

[0021] Because motors may be subjected to complex force feedback during long-term operation, such as the drive motor used to drive the shaft of a crusher, the internal rotor generates a small amount of tiny metal particles and heat due to friction during high-speed rotation. Generally, the higher the temperature, the more severe the wear and the more metal particles are generated. Especially when crushing objects with high hardness, the stress feedback is greater, and the instantaneous wear of the rotor is larger. The more frequently this event occurs, the faster the accumulation of metal particles in the oil in the closed circuit will be. Therefore, in order to maintain the service life of the hydraulic system, the frequency of switching to open mode will be increased. This shortens the time of closed drive and increases the number of open drive operations. From the perspective of continuous drive, energy loss also increases, and the effect of reducing energy loss is reduced.

[0022] When the hydraulic oil flowing through the motor becomes hotter, creating a larger pressure difference between the inlet and outlet, the pressure difference feedback controls the opening to increase. This forces more high-temperature oil containing metal particles from the closed-loop circuit to be expelled and sent to the external oil tank. Since increased oil temperature may be accompanied by increased instantaneous wear, increasing the oil change volume further removes more metal particles, thus slowing their accumulation in the closed-loop circulating hydraulic oil. This extends the duration of a single closed-loop drive and reduces the number of open-loop drive switching cycles. Ultimately, this effectively reduces wear and extends the lifespan of system components.

[0023] Since the external oil tank is only used for short-term open-loop drive and oil replenishment, the required oil volume is also small, and the oil tank can be designed to be relatively small. The entire hydraulic system is compact and small, thus meeting the drive requirements of more precise systems.

[0024] The closed-loop portion located inside the valve block 3 includes an oil supply channel 12 and an oil return channel 21. Two hydraulic drive valves 5 are correspondingly provided, one for connecting the oil supply channel 12 to the external oil tank 4, and the other for connecting the oil return channel 21 to the external oil tank 4. The hydraulic drive valves 5 are hydraulically driven shuttle valves of the same specification. When a pressure difference is generated between the inlet and outlet of the hydraulic oil in the driving component, the two shuttle valves open synchronously and close synchronously when the pressure difference tends to disappear. This allows a certain amount of oil to be drawn simultaneously from both reciprocating oil circuits between the driving pump and the driven component, preventing a sudden drop in oil pressure on either the supply or return side.

[0025] Based on this, the valve block 3 is equipped with an energy storage channel 6. The oil inlet of the energy storage channel 6 is connected to the external oil tank 4 via a hydraulic pipeline, and its oil outlet is connected to the oil supply channel 12 and the oil return channel 21 via two branch channels. Furthermore, the connection positions of the energy storage channel 6 and the corresponding hydraulic drive valve 5 on the two closed-loop channels are close to each other. This allows clean, cold oil to be replenished into the channel the instant the hydraulic drive valve 5 opens or the flow rate increases, thereby avoiding significant oil pressure fluctuations caused by the opening or increase of oil flow, and maintaining the continuous open state of the hydraulic drive valve 5. Since this oil change process occurs instantaneously during the drive process, it helps maintain the stability of the hydraulic system.

[0026] Specifically, taking the closed-loop operation as a reference, in the direction of oil flow in the oil supply channel 12 and the oil return channel 21, the connection point of the energy storage channel 6 with both is located in front of the connection point of the hydraulic drive valve 5 with both. When the hydraulic drive valve 5 draws oil from the channel back to the external oil tank, the pressure in the corresponding pipeline will drop sharply due to the instantaneous loss of a large amount of hydraulic oil. In the original direction of hydraulic oil flow, the hydraulic oil still retains its forward momentum, thus forming a low-pressure zone slightly in front of the instantaneous suction area. At this time, the cold oil replenished from the oil tank is directly input to the front of the suction position, which can accurately and directly replenish the low-pressure position. The original suction position will be replenished by the original oil in the rear channel, which can reduce the oil pressure fluctuation when changing the amount of oil exchanged.

[0027] The external oil tank 4 is connected to the drive pump 1 via the replenishment oil pipeline 7. The oil outlet of the replenishment oil pipeline 7 is connected to the two ports of the hydraulic chamber of the drive pump 1 via two branch pipes, and each branch pipe is equipped with a hydraulic check valve. The energy storage channel 6 and the oil inlet of the replenishment oil pipeline 7 are both connected to the external oil tank 4 via the replenishment oil pump 8. When the hydraulic drive valve 5 is a shuttle valve, the linear valve characteristics of the shuttle valve can be utilized by setting limit switches at both ends of its valve block movement trajectory. These two limit switches control the opening and closing of the replenishment oil pump 8. When the shuttle valve opens due to pressure, the limit switches are triggered to control the replenishment oil pump 8 to work, ensuring that dust-free cold oil is stably and smoothly replenished into the closed loop.

[0028] While replenishing oil at the oil change point can stabilize oil pressure changes to some extent, it cannot completely eliminate the impact. Therefore, oil is replenished at both ends of the hydraulic chamber of the drive pump to reduce the impact of such fluctuations on the drive pump. Instead, the fluctuations occur within the hydraulic oil delivery pipeline and tend to stabilize during transmission.

[0029] An accumulator is connected in series to the main channel of the energy storage channel 6, and a hydraulic check valve is connected in series in front of the accumulator. At the oil outlet of the energy storage channel 6, two hydraulic check valves connect it to the oil supply channel 12 and the oil return channel 21 respectively, forming an energy storage section between the three hydraulic check valves. This energy storage section is connected to the external oil tank 4 via an overflow safety valve. This ensures that the energy storage section always stores cold oil at a certain pressure. When the hydraulic drive valve 5 opens or the flow rate increases, the oil in the energy storage section can actively push open the hydraulic check valve under pressure, and the degree of opening depends on the oil pressure change at the corresponding position in the closed circuit. Since the replenishing pump is usually not working, the triggering of the shuttle valve for oil release occurs instantaneously, while the triggering of the replenishing pump may take some time. Therefore, by using the energy storage section as a transition section, timely oil replenishment response can be achieved. Immediately following the start of the replenishing pump, the energy storage section can be refilled, preparing for the next oil change. Further reduce the impact of triggering oil changes on the closed-loop drive state.

[0030] Example: The valve block 3 includes a four-way switching valve 31, one set of which has an inlet / outlet port connected to the open oil supply line 41 and the oil supply channel 12, and the other set of which has an inlet / outlet port connected to the return oil channel 21 and the open return oil line 42. The inlet section of the open oil supply line 41 and the outlet end of the open return oil line 42 are both connected to the external oil tank 4. The oil supply channel 12 is connected in series with a hydraulic isolation valve 121. The valve block 3 includes a three-way isolation control valve 32, whose three ends are respectively connected to the hydraulic drive interface of the open oil supply line 41, the open return oil line 42, and the hydraulic isolation valve 121, enabling switching of the connection relationship between the open oil supply line 41, the open return oil line 42, and the hydraulic drive interface of the hydraulic isolation valve 121.

[0031] Both the switching valve 31 and the isolation control valve 32 are electromagnetically controlled valves. When switching to an open-loop drive mode is required, the drive pump is stopped, and both the switching valve 31 and the isolation control valve 32 are simultaneously energized. This isolates the oil supply direction of the drive pump by the hydraulic isolation valve 121, creating a new oil supply and return path between the external oil tank and the driven component, thus forming an open hydraulic circuit. At this time, the oil tank's supply pump operates, drawing hydraulic oil. Part of the extracted hydraulic oil enters the open circuit to continue powering the drive component, while part passes through the isolation control valve 32 and enters the hydraulic drive interface of the hydraulic isolation valve 121, thereby pushing the internal valve block to move and block its inlet and outlet ports. However, when switching back to a closed-loop mode is required, simply de-energize the two electromagnetically controlled valves, causing the valve block of the hydraulic isolation valve 121 to drive the oil in the hydraulic chamber back to the external oil tank, thereby resetting the internal valve block and reopening the oil supply channel 12.

[0032] The above are merely preferred embodiments of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this utility model, and these improvements and modifications should also be considered within the protection scope of this utility model.

Claims

1. An open-closed hybrid hydraulic system, characterized in that: It includes a drive pump (1) and a driven component (2), whose hydraulic chambers are circulated together to form a closed loop; it also includes an external oil tank (4), which can be connected to the hydraulic chamber of the driven component (2) through a valve block (3) to form an open loop; Part of the closed-loop pipeline references the internal channel of the valve block (3), enabling the valve block (3) to switch the connection between the drive pump (1), the external oil tank (4) and the driven component (2); The valve block (3) includes a pressure-controlled return oil channel, which can be controlled to be turned on according to the pressure difference between the hydraulic chamber inlet and outlet ports of the driven component (2). The closed circuit is connected to the external oil tank (4) through the pressure-controlled return oil channel, so that the return oil of the closed circuit is connected to the external oil tank (4).

2. The open-closed hybrid hydraulic system according to claim 1, characterized in that: The closed circuit located inside the valve block (3) includes an oil supply channel (12) and an oil return channel (21). The inlet end of the pressure-controlled oil return channel is connected to the oil supply channel (12) and the oil return channel (21) through two branch channels respectively, and both branch channels are equipped with hydraulic drive valves (5).

3. The open-closed hybrid hydraulic system according to claim 2, characterized in that: The valve block (3) is provided with an energy storage channel (6), the oil inlet end of which is connected to the external oil tank (4), and the oil outlet end is connected to the oil supply channel (12) and the oil return channel (21) respectively through two branch channels.

4. The open-closed hybrid hydraulic system according to claim 3, characterized in that: The external oil tank (4) is connected to the drive pump (1) through the oil replenishment pipeline (7). The oil outlet of the oil replenishment pipeline (7) is connected to the two ports of the hydraulic chamber of the drive pump (1) through two branch pipes, and each branch pipe is equipped with a hydraulic check valve.

5. The open-closed hybrid hydraulic system according to claim 4, characterized in that: The inlet ends of the energy storage channel (6) and the oil replenishment pipeline (7) are both connected to the external oil tank (4) via an oil replenishment pump (8).

6. The open-closed hybrid hydraulic system according to claim 5, characterized in that: A hydraulic check valve is connected in series in the main channel of the energy storage channel (6), and two hydraulic check valves are connected to the oil supply channel (12) and the oil return channel (21) at its oil outlet end, forming an energy storage section between the three hydraulic check valves.

7. The open-closed hybrid hydraulic system according to claim 6, characterized in that: The valve block (3) includes a four-way switching valve (31), one set of which has an inlet and outlet port connected to an open oil supply line (41) and the oil supply channel (12), and another set of which has an inlet and outlet port connected to the return oil channel (21) and the open return oil line (42). The inlet end of the open oil supply line (41) and the outlet end of the open return oil line (42) are both connected to the external oil tank (4).

8. The open-closed hybrid hydraulic system according to claim 7, characterized in that: The oil supply channel (12) is connected in series with a hydraulic shut-off valve (121). The valve block (3) includes a three-way shut-off control valve (32), whose three-end interface is connected to the open oil supply line (41), the open oil return line (42) and the hydraulic drive interface of the hydraulic shut-off valve (121) respectively, and can switch the conduction relationship between the open oil supply line (41) and the open oil return line (42) and the hydraulic drive interface of the hydraulic shut-off valve (121).

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