Dynamic balance hydraulic system of variable displacement motor

Abstract

The utility model discloses a variable displacement motor dynamic balance hydraulic system which comprises a main control loop and a stable branch, and the main control loop is communicated with an oil tank and a hydraulic cavity of a variable displacement motor and used for circularly supplying oil to drive the variable displacement motor to work. A hydraulic cavity of the variable displacement motor is communicated with the oil tank through the stabilizing branch, and the stabilizing branch is used for communicating an oil outlet of the hydraulic cavity of the variable displacement motor with an oil return connector of the oil tank according to the pressure difference of an oil inlet and an oil outlet of the hydraulic cavity of the variable displacement motor and used for reducing the temperature of flowing oil; the oil tank is further communicated with the oil supply side of the main control loop 1 through an oil supplementing branch. Dynamic balance in the working process of the variable displacement motor hydraulic system can be guaranteed, so that stable working is achieved, and the service life of the motor is prolonged.

Description

TECHNICAL FIELD

[0001] The utility model relates to hydraulic system technical field, especially a variable motor dynamic balance hydraulic system. BACKGROUND

[0002] Variable motor as common hydraulic system execution element, in the running process, will inevitably produce internal leakage, lead to the loss of oil in the circulation process, thereby lead to the fluctuation of hydraulic oil flow rate and pressure difference, influence motor operation's stability. And the parts in the motor generate a lot of heat in the working process due to friction, the hydraulic oil temperature after the motor is very high, under the uninterrupted circulation of hydraulic oil, high-temperature back oil can make the temperature of oil in the oil tank continuously improve, lead to the temperature of whole hydraulic circuit all rises, simultaneously high temperature can also cause the pressure difference of motor inlet and outlet, lead to motor internal leakage, also influence the running stability of motor. SUMMARY

[0003] The utility model discloses a variable motor dynamic balance hydraulic system can guarantee the dynamic balance of variable motor hydraulic system working process, to reach the stable work, prolong the service life of motor.

[0004] Technical scheme: in order to realize the above-mentioned purpose, a variable motor dynamic balance hydraulic system of the utility model, including main control circuit and stable branch, the main control circuit is communicated oil tank and the hydraulic cavity of variable motor, is used for circulating oil supply drive the variable motor work;The hydraulic cavity of variable motor is communicated with the oil tank through the stable branch, the stable branch is used for according to the pressure difference of variable motor hydraulic cavity inlet and outlet oil port and the back oil interface of oil tank of the variable motor hydraulic cavity inlet and outlet oil port conduction, and is used for reducing the temperature of oil flow;The oil tank still is communicated with the oil supply side of main control circuit 1 through the oil supplement branch.

[0005] Further, the main control circuit includes the confluence valve block, the oil tank is communicated with the oil supply interface and back oil interface of one side of the confluence valve block through the hydraulic pump, the oil supply interface of the other side of the confluence valve block is communicated with the oil inlet of the hydraulic cavity of variable motor, and the oil outlet of the hydraulic cavity of variable motor is communicated with the back oil interface of the confluence valve block.

[0006] Further, the oil supplement branch includes the oil supplement pump, and the oil supply interface of the oil tank is communicated with the oil cavity of the hydraulic pump through the oil supplement pump.

[0007] Further, the oil supply interface of the oil tank is also communicated with the oil inlet of the hydraulic cavity of variable motor through the oil supplement pump.

[0008] Further, the stable branch comprises a normally closed shuttle valve, and the high-pressure side of the variable motor hydraulic cavity inlet and outlet oil port is communicated with the valve opening driving interface of the shuttle valve.

[0009] Further, the variable motor is a group of serial motors, comprising multiple hydraulic motor units coaxially connected in series.

[0010] Further, the confluence valve block is communicated with the hydraulic cavities of the multiple hydraulic motor units through multiple distribution valve blocks.

[0011] Further, the hydraulic pump is a group of serial pumps, comprising multiple hydraulic pump units coaxially connected in series.

[0012] Further, each hydraulic pump unit is communicated with the confluence valve block through a separate pipeline.

[0013] Further, the oil outlet end of the oil supplement pump is communicated with the hydraulic cavities of the multiple hydraulic motor units through an oil supplement distribution valve block.

[0014] Beneficial effects: the variable motor dynamic balance hydraulic system of the utility model provides additional oil return route through the stable branch, when the motor generates larger pressure difference between inlet and outlet oil ports due to the outlet oil temperature being too high, part of the high-temperature oil liquid returns from the stable branch, returns to the oil tank after cooling, avoids heat circulating and accumulating in the main control circuit, ensures the temperature stability of the entire hydraulic system, and thus ensures the stable operation of the motor. The oil pressure change caused by oil distribution and return is compensated through the oil supplement branch, and the hydraulic oil loss caused by the internal leakage of the motor and the hydraulic pump is compensated, the main control circuit oil pressure is stabilized, and the stable operation of the motor is further ensured. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 It is a principle block diagram of the variable motor dynamic balance hydraulic system of the utility model;

[0016] Figure 2 It is a principle schematic block diagram of the embodiment system of the utility model. DETAILED DESCRIPTION

[0017] The utility model will be explained further in combination with the drawings.

[0018] As shown in the accompanying Figures 1-2The variable motor dynamic balance hydraulic system comprises a main control loop 1 and a stable branch 2, the main control loop 1 is communicated with an oil tank 4 and a hydraulic cavity of a variable motor 6, and is used for circulating oil supply to drive the variable motor 6 to work; the hydraulic cavity of the variable motor 6 is communicated with the oil tank 4 through the stable branch 2, the stable branch 2 is used for conducting the oil outlet of the hydraulic cavity of the variable motor 6 and an oil return interface of the oil tank 4 according to a pressure difference between inlet and outlet of the hydraulic cavity of the variable motor 6, and is used for reducing the temperature of oil flowing. Wherein, the main control loop 1, the oil tank 4 and the variable motor 6 constitute a closed hydraulic system, after oil is extracted from the oil tank, high-pressure oil is formed in the main control loop and is used in circulation. The stable branch provides an additional oil return route, directly returns oil to the oil tank without passing through the oil pump of the main control loop, and the oil return stroke is longer than the oil return stroke in the main control loop, when the outlet oil temperature of the motor is too high to cause a large pressure difference between the inlet and outlet, part of the high-temperature low-pressure oil is directly returned to the oil tank through the stable branch, which can first avoid the accumulation of heat in the main control loop, affect the working efficiency of the hydraulic pump and the motor, and ensure the temperature stability of the whole hydraulic system. Preferably, the pipeline of the stable branch 2 can pass through a cooling device for active cooling. Since part of the oil is returned through the stable branch, the oil pressure of the main control loop will instantaneously decrease, therefore, the oil tank 4 is also communicated with the oil supply side of the main control loop 1 through a supplement oil branch, which can not only make up for the change of oil pressure caused by oil return, but also make up for the loss of hydraulic oil caused by leakage of the motor and the hydraulic pump, so as to realize the stability of the oil pressure in the main control loop through oil supplement.

[0019] The main control loop 1 comprises a confluence valve block 3, the oil tank 4 is communicated with an oil supply interface and an oil return interface on one side of the confluence valve block 3 through a hydraulic pump 5, an oil supply interface on the other side of the confluence valve block 3 is communicated with an oil inlet of the hydraulic cavity of the variable motor 6, and an oil outlet of the hydraulic cavity of the variable motor 6 is communicated with an oil return interface of the confluence valve block 3. The confluence valve block can realize the communication of multiple hydraulic pumps with the oil tank, so that multiple hydraulic pumps can be combined to work to meet the demand of the variable motor for hydraulic oil flow regulation, or multiple variable pumps are communicated with the oil tank, a single variable pump is used to meet the variable regulation demand, and multiple variable pumps are alternately matched to work, so as to reduce the working strength of a single hydraulic pump, prolong the service life of the hydraulic pump, make the work of the variable motor more continuous and persistent, and ensure the stability of the work.

[0020] The supplement oil branch comprises a supplement oil pump 7, an oil supply interface of the oil tank 4 is communicated with an oil cavity of the hydraulic pump 5 through the supplement oil pump 7. The oil supply interface of the oil tank 4 is also communicated with an oil inlet of the hydraulic cavity of the variable motor 6 through the supplement oil pump 7. Wherein, the supplement oil pump 7 adopts a small-flow hydraulic pump, actively extracts cold oil from the oil tank, part of which is supplied to the hydraulic pump for oil supplement, maintains the system stability, and another part is supplied to the variable motor for internal element flushing.

[0021] The stable branch 2 includes a normally closed shuttle valve, and the high-pressure side of the variable motor 6 hydraulic cavity inlet and outlet port is communicated with the opening valve driving interface of the shuttle valve. It can quickly respond to the pressure difference change of the motor inlet and outlet port, and in the case of relatively stable pressure difference of the motor inlet and outlet port, the stable branch is closed, and the hydraulic oil is normally circulated in the main control circuit. When the oil temperature passing through the motor is high, the high-temperature oil causes the outlet oil pressure to decrease due to the decrease of viscosity, and at this time the pressure difference of the inlet and outlet ports is enough to overcome the elastic force of the piston valve return spring in the shuttle valve, so that the shuttle valve is opened, and part of the high-temperature low-pressure oil flows through the shuttle valve and finally returns to the oil tank. At the moment of opening, part of the hydraulic oil in the closed-loop return oil branch is lost, and the closed-loop system will be lowered due to the oil pressure. At this time, the drive oil supplement pump is driven to supplement oil. At this time, the oil directly supplemented to the motor hydraulic cavity is cold oil, which can cool the internal elements and flush the internal elements. At the same time, the oil supplemented to the hydraulic pump also cools the hydraulic pump, and is pressurized through the hydraulic pump to increase the oil pressure of the closed-loop circuit, thereby stabilizing the oil pressure of the main control circuit. When the pressure difference decreases, the piston valve in the shuttle valve resets under the action of the reset spring to reseal the stable branch, and the hydraulic oil continues to circulate between the hydraulic pump and the variable motor along the main control circuit. The oil supplement branch supplements oil when the oil volume is lost.

[0022] Among them, the oil supplement pump 7 is a series pump, including two pump body units 70 coaxially connected in series, the oil cavity inlet of the two pump body units 70 is connected with the oil tank, and the outlet of the two pump body units 70 is connected with the oil supplement branch and the stable branch respectively, as shown in the accompanying drawings. Figure 2 As shown in the accompanying drawings, the pump body unit 70 connected with the oil supplement branch is divided into two branches at the outlet, one branch is connected with the hydraulic pump oil cavity inlet of the main control circuit 1, and the other branch is directly connected with the hydraulic cavity of the variable motor. The pump body unit 70 connected with the stable branch is directly connected with the middle part of the stable branch, and when the stable branch is opened to realize backflow, a part of the cold oil in the oil tank is extracted and mixed with the hot oil in the stable branch, and then naturally cooled through a section of pipeline, so that the temperature of the high-temperature oil decreases to a lower temperature when it reaches the oil tank, and the temperature when entering the oil tank is maintained at about 30°C. The cooling system of the oil tank is cooled to improve the cooling speed, ensure that the oil extracted from the oil tank is cold oil, and further ensure that the supplemented oil can replace the high-temperature oil to reduce the temperature of the closed-loop hydraulic system, thereby ensuring the stable operation of the closed-loop hydraulic system.

[0023] The variable motor 6 is a series motor, including a plurality of hydraulic motor units 61 coaxially connected in series. The combined valve block 3 is communicated with the hydraulic cavities of the plurality of hydraulic motor units 61 through a plurality of shunt valve blocks 8. The series motor can realize larger flow hydraulic drive single shaft rotation, and the oil cavity of each motor unit is independently circulated with the combined valve block through the shunt valve block to form an independent shunt system, thereby accurately controlling the flow through the single oil cavity, ensuring the synchronism of the flow of the two oil cavities, and further ensuring the stable operation of the series motor.

[0024] The hydraulic pump 5 is a group of series pumps, comprising a plurality of hydraulic pump units 51 coaxially connected in series. Each of the hydraulic pump units 51 is communicated with the confluence valve block 3 through a separate pipeline. The coaxial driving improves the efficiency, the same oil amount is taken in the oil supply valve cavities in the confluence valve block, the total input flow of the entire motor is ensured to be stable, and when the oil is returned, the return oil ports of the respective hydraulic pump units are communicated with the return oil valve cavities in the confluence valve block, so that the total output flow of the entire motor is ensured to be stable.

[0025] Due to the temperature difference in the oil cavities of the plurality of motor units and the inconsistent oil loss, the oil outlet end of the oil supplement pump 7 is communicated with the hydraulic cavities of the plurality of hydraulic motor units 61 through an oil supplement shunt valve block 71. The oil supplement shunt valve block controls the shunt flow of the oil supplement by detecting the oil pressure change of a single shunt system, and the oil supplement pump controls the oil supplement extraction power by the total pressure drop of the series motor, and the opening and closing of the stable branch is also controlled by the total inlet and outlet oil port pressure difference of the series motor. After being turned on, the plurality of motor unit oil cavities push out the same amount of high-temperature hydraulic oil to flow through the stable branch back to the oil tank, and the specific amount is determined by the selected shuttle valve specification. That is, the total inlet and outlet oil port pressure difference of the series motor controls the shunt return, the shunt flow of the plurality of motor units is consistent, and the main difference is caused by the oil loss of the respective oil cavities. The total pressure drop of the main control circuit controls the oil supplement pump to extract the oil supplement oil amount, so as to ensure that the total oil supplement amount is sufficient. The oil amount used for the oil supplement and pressurization part is automatically and uniformly distributed to the oil cavities of the plurality of hydraulic pump units, so as to improve the oil pressure of the entire closed loop. The oil amount used for the flushing part can directly and quickly reach the low pressure side of the motor oil cavity, so as to be accurately distributed by the oil supplement shunt valve block 71, to quickly make up the pressure loss, and to ensure the dynamic balance of the entire system.

[0026] The above is only the preferred embodiment of the present application, and it should be pointed out that for ordinary skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A variable-displacement motor dynamically balanced hydraulic system, characterized by: The system comprises a main control circuit (1) and a stabilizing branch (2), the main control circuit (1) is connected with the oil tank (4) and the hydraulic cavity of the variable motor (6) for circulating oil to drive the variable motor (6) to work, the hydraulic cavity of the variable motor (6) is connected with the oil tank (4) through the stabilizing branch (2), the stabilizing branch (2) is used for connecting the oil return interface of the hydraulic cavity of the variable motor (6) and the oil tank (4) according to the pressure difference between the oil inlet and the oil outlet of the hydraulic cavity of the variable motor (6), and is used for reducing the temperature of the oil flowing through, and the oil tank (4) is also connected with the oil supply side of the main control circuit (1) through an oil supplement branch.

2. A dynamically balanced hydraulic system for a variable capacity motor as defined in claim 1, wherein: The main control circuit (1) comprises a confluence valve block (3), the oil tank (4) is connected with the oil supply interface and the oil return interface of one side of the confluence valve block (3) through a hydraulic pump (5), the oil supply interface of the other side of the confluence valve block (3) is connected with the oil inlet of the hydraulic cavity of the variable motor (6), and the oil outlet of the hydraulic cavity of the variable motor (6) is connected with the oil return interface of the confluence valve block (3).

3. A dynamically balanced hydraulic system for a variable capacity motor as defined in claim 2 wherein: The oil supplement branch comprises an oil supplement pump (7), and the oil supply interface of the oil tank (4) is connected with the oil cavity of the hydraulic pump (5) through the oil supplement pump (7).

4. A dynamically balanced hydraulic system for a variable capacity motor as set forth in claim 3, wherein: The oil supply interface of the oil tank (4) is also connected with the oil inlet of the hydraulic cavity of the variable motor (6) through the oil supplement pump (7).

5. A dynamically balanced hydraulic system for a variable displacement motor as set forth in claim 4, wherein: The stabilizing branch (2) comprises a normally closed shuttle valve, and the high-pressure side of the oil inlet and the oil outlet of the hydraulic cavity of the variable motor (6) is connected with the valve opening driving interface of the shuttle valve.

6. A dynamically balanced hydraulic system for a variable displacement motor as set forth in claim 5, characterized in that: The variable motor (6) is a group of series motors, comprising a plurality of hydraulic motor units (61) coaxially connected in series.

7. A dynamically balanced hydraulic system for a variable capacity motor as defined in claim 6 wherein: The confluence valve block (3) is connected with the hydraulic cavities of a plurality of hydraulic motor units (61) through a plurality of shunt valve blocks (8) respectively.

8. A dynamically balanced hydraulic system for a variable displacement motor as set forth in claim 7, characterized in that: The hydraulic pump (5) is a group of series pumps, comprising a plurality of hydraulic pump units (51) coaxially connected in series.

9. A dynamically balanced hydraulic system for a variable displacement motor as set forth in claim 8, wherein: Each hydraulic pump unit (51) is connected with the confluence valve block (3) through a separate pipeline.

10. A dynamically balanced hydraulic system for a variable displacement motor as set forth in claim 9, characterized in that: The oil outlet end of the oil supplement pump (7) is connected with the hydraulic cavities of a plurality of hydraulic motor units (61) through an oil supplement shunt valve block (71) respectively.

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