Patent Application
20240011602
The present application claims for the benefits of the Chinese Patent Application No. 202011065237.X filed on Sep. 30, 2020, the content of which is incorporated herein by reference.
The present disclosure relates to construction machineries, in particular to a rotation speed control method for a heat dissipation device of a construction machinery. In addition, the present disclosure further relates to a pressure-compensation controlled hydraulic pump, a rotation speed control system for a heat dissipation device of a construction machinery, and a construction machinery.
During the operation of a large-size construction machinery, some of the pressure energy in the hydraulic system is converted into heat energy, consequently the oil temperature in the hydraulic system is increased. To maintain the temperature of the hydraulic oil within a reasonable range, a heat dissipation device has to be utilized to dissipate the heat from the hydraulic oil. Large-size construction machineries, such as excavators and loaders, etc., usually employ a separate heat dissipation control system, which is to say, the input shaft of a cooling fan is not connected to the output shaft of the engine; instead, the cooling fan is driven by a hydraulic motor separately to rotate.
However, in the working process of a construction machinery, the rotation speed of the engine 2 varies with the load, and the speed variation of the engine 2 leads to the variation of the rotation speed of the cooling pump 1, consequently leads to the variation of the output flow rate of the cooling pump 1; the fluctuations of the output flow rate of the cooling pump 1 result in fluctuations of the rotation speed of the fan motor 3, thereby result in fluctuations of the rotation speed of the fan 4. As a result, the rotation speed of the fan 4 cannot be stabilized at a demand value, resulting in an adverse effect on the heat dissipation effect of the hydraulic system on one hand and high noise of the fan 4 on the other hand.
In view of the above problems, it is desirable to design a pressure-compensation controlled hydraulic pump.
The technical problem to be solved in a first aspect of the present disclosure is to provide a rotation speed control method for a heat dissipation device of a construction machinery, which can stabilize the output flow rate of a hydraulic pump at a demand value, thereby stabilize the rotation speed of the heat dissipation device within a preset rotation speed range.
The technical problem to be solved in a second aspect of the present disclosure is to provide a pressure-compensation controlled hydraulic pump, which can stabilize the output flow rate of a hydraulic pump at a demand value.
The technical problem to be solved in a third aspect of the present disclosure is to provide a rotation speed control system for a heat dissipation device of a construction machinery, which can stabilize the rotation speed of a cooling fan at a demand value.
The technical problem to be solved in a fourth aspect of the present disclosure is to provide a construction machinery, which has a hydraulic system that achieves a good heat dissipation effect and a heat dissipation device that generates lower noise.
To solve the above-mentioned technical problems, in a first aspect, the present disclosure provides a rotation speed control method for a heat dissipation device of a construction machinery, which comprises the following steps: in a first step, acquiring the oil temperature of hydraulic oil in a hydraulic system where the heat dissipation device is located, obtaining a corresponding first pressure value according to the oil temperature of the hydraulic oil, and generating a corresponding second pressure value according to a load pressure generated by the heat dissipation device; in a second step, comparing the first pressure value with the second pressure value; and in a third step, adjusting the displacement of a hydraulic pump for driving the heat dissipation device in the hydraulic system according to a result of the comparison, so that the output flow rate of the hydraulic pump is stabilized within a preset flow rate range when the rotation speed of the hydraulic pump varies, thereby the rotation speed of the heat dissipation device is stabilized within a preset rotation speed range.
Preferably, the first step comprises: obtaining a corresponding current value according to the oil temperature of the hydraulic oil, and obtaining the corresponding first pressure value according to the current value.
Preferably, the second step comprises: inputting the first pressure value and the second pressure value to a pressure comparison module respectively, so as to compare the first pressure value with the second pressure value.
Specifically, the third step comprises: controlling the displacement of the hydraulic pump to increase when the rotation speed of the hydraulic pump is decreased and the first pressure value is greater than the second pressure value, and controlling the displacement of the hydraulic pump to decrease when the rotation speed of the hydraulic pump is increased and the first pressure value is smaller than the second pressure value.
In a second aspect, the present disclosure provides a pressure-compensation controlled hydraulic pump, which comprises a pressure control device, a hydraulic pump and a displacement adjusting device, wherein the displacement adjusting device is adapted to compare a first pressure value generated by the pressure control device with a second pressure value at an oil outlet of the hydraulic pump, and to adjust the displacement of the hydraulic pump according to a result of the comparison, so that the output flow rate of the hydraulic pump is stabilized within a preset flow rate range when the rotation speed of the hydraulic pump varies.
Preferably, the pressure control device is an electric proportional pressure compensator.
Preferably, the displacement adjusting device comprises a hydraulic control reversing valve and a servo cylinder for adjusting the displacement of the hydraulic pump, the oil outlet of the hydraulic pump is connected to an internal output oil path, an oil inlet of the hydraulic pump is connected to an internal input oil path, a first hydraulic control port of the hydraulic control reversing valve is connected to an internal oil drain path via the pressure control device, a piston chamber of the servo cylinder is connected to the internal output oil path and the internal oil drain path respectively via the hydraulic control reversing valve, a pressure difference between the pressure control device and an oil outlet pressure of the hydraulic pump acts on a valve spool of the hydraulic control reversing valve via the first hydraulic control port and a second hydraulic control port of the hydraulic control reversing valve to drive the hydraulic control reversing valve to perform reversing, thereby selectively enables the piston chamber of the servo cylinder to be in communication with the internal output oil path or the internal oil drain path.
Specifically, the first hydraulic control port is connected to the internal output oil path via a hydraulic control oil inlet path provided with a first throttle valve, and a second hydraulic control port of the hydraulic control reversing valve is connected to the internal output oil path.
Specifically, the hydraulic pump is a variable displacement plunger pump.
Specifically, the hydraulic control reversing valve is a two-position three-way reversing valve.
Preferably, a second throttle valve is provided in a connection oil path between the piston chamber of the servo cylinder and the hydraulic control reversing valve.
Specifically, a safety oil path is connected between the piston chamber of the servo cylinder and the internal oil drain path and provided with a third throttle valve, one end of the safety oil path is connected to the connection oil path between the piston chamber of the servo cylinder and the hydraulic control reversing valve, and the connection point is located between the first throttle valve and the second throttle valve, and the other end of the safety oil path is connected to the internal oil drain path at a position after the connection position of an oil outlet of the electric proportional pressure compensator.
In a third aspect, the present disclosure provides a rotation speed control system for a heat dissipation device of a construction machinery, comprising a temperature sensor for detecting the oil temperature of hydraulic oil, a fan motor for driving a fan to rotate, a controller, and the pressure-compensation controlled hydraulic pump according to any of the technical schemes in the second aspect, wherein the temperature sensor is electrically connected to the controller, and the controller can receive a signal from the temperature sensor and control the first pressure value generated by the pressure control device according to the signal, and the pressure generated by the fan motor when driving the fan is fed back to the oil outlet of the hydraulic pump to form the second pressure value.
In a fourth aspect, the present disclosure provides a construction machinery, comprising a heat radiator for cooling hydraulic oil and the rotation speed control system for a heat dissipation device of a construction machinery according to the technical scheme in the third aspect, wherein the fan motor can drive the fan to rotate to cool the heat radiator.
With the pressure-compensation controlled hydraulic pump provided in the basic embodiments of the present disclosure, when the rotation speed of a power drive unit that provides mechanical energy to the hydraulic pump varies, the displacement adjusting device can adjust the displacement of the hydraulic pump, so that the output flow rate of the hydraulic pump is stabilized at a demand value, thereby the rotation speed of a actuator element driven by the hydraulic pump is stabilized at a demand value, and the operation of the actuator element is more stable.
Other advantages of the present disclosure and the technical effects of preferred embodiments will be further detailed below in the embodiments.
Some embodiments of the present disclosure will be detailed below with reference to the accompanying drawings. It should be understood that the embodiments described herein are only provided to describe and explain the present disclosure, but are not intended to constitute any limitation to the present disclosure.
In the present disclosure, it should be noted that the terms “connect” and “arrange” shall be interpreted in their general meanings, for example, a connection may be a fixed connection, a detachable connection, or an integral connection; may be a direct connection or an indirect connection via an intermediate medium, or internal communication between two elements or interaction between two elements, unless otherwise specified and defined explicitly. Those having ordinary skills in the art may interpret the specific meanings of the terms in the present disclosure in their context.
The terms “first”, “second” and “third” are only for a descriptive purpose, but shall not be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Therefore, features defined by “first”, “second” or “third” may expressly or impliedly include one or more features.
Preferably, the displacement control mechanism of the hydraulic system comprises an electric proportional pressure compensator, a corresponding current value is obtained according to the oil temperature of the hydraulic oil, and a current value is inputted into the electric proportional pressure compensator to control an opening pressure of the electric proportional pressure compensator, wherein the opening pressure is a first pressure value.
Specifically, a pressure comparison module of the hydraulic system comprises a servo cylinder 13 for controlling the displacement and a hydraulic control reversing valve 12 for controlling the servo cylinder 13 to extend and retract, and the first pressure value and the second pressure value act on hydraulic control ports at the two ends of the hydraulic control reversing valve 12 respectively; the valve spool of the hydraulic control reversing valve 12 can move to the smaller one of the first pressure value and the second pressure value, thereby the first pressure value is compared with the second pressure value. The displacement of the hydraulic pump is controlled to increase when the rotation speed of the hydraulic pump is decreased and the first pressure value is greater than the second pressure value, and the displacement of the hydraulic pump is controlled to decrease when the rotation speed of the hydraulic pump is increased and the first pressure value is smaller than the second pressure value.
In an embodiment of the present disclosure, as shown in
The working principle of the pressure-compensation controlled hydraulic pump in the above embodiment of the present disclosure is described below.
When the rotation speed of the power drive device 34 is increased and causes an increased rotation speed of the hydraulic pump 11, as shown in
Thus, when the rotation speed of the power drive device 34 varies, the servo cylinder 13 can adjust the displacement of the hydraulic pump 11, so that the output flow rate of the hydraulic pump 11 is essentially stabilized at the demand value, thereby the rotation speed of the actuator element driven by the hydraulic pump is stabilized at the demand value, and the operation of the actuator element is more stable; moreover, by controlling the opening pressure of the electric proportional pressure compensator 14 via the controller 15, the demand value of the output flow rate of the hydraulic pump 11 can be adjusted conveniently; the valve spool of the hydraulic control reversing valve 12 moves in small amplitudes continuously under the action of the opening pressure of the electric proportional pressure compensator 14 and the pressure at the oil outlet of the hydraulic pump to adjust the relative position in the valve body, so that oil flows into or out of the piston chamber of the servo cylinder 13, thereby the output flow rate of the hydraulic pump 11 is adjusted accurately and sensitively.
Specifically, the hydraulic pump 11 is a variable displacement plunger pump, the displacement of which can be adjusted more conveniently. The push rod of the servo cylinder 13 can adjust the displacement of the hydraulic pump 11 by adjusting the inclination angle of a swash plate of the variable displacement plunger pump.
Preferably, a second throttle valve 17 is provided in the connection oil path between the piston chamber of the servo cylinder 13 and the hydraulic control reversing valve 12. The second throttle valve 17 can adjust the oil inflow rate and oil outflow rate of the piston chamber of the servo cylinder 13; when the flow rate through the second throttle valve 17 is high, the response rate of the pressure-compensation controlled hydraulic pump is high, but the disturbances to the hydraulic oil and the impact on the pipeline in the system are high.
Preferably, a safety oil path 25 is connected between the piston chamber of the servo cylinder 13 and the internal oil drain path 23 and is provided with a third throttle valve 18, one end of the safety oil path 25 is connected to the connection oil path between the piston chamber of the servo cylinder 13 and the hydraulic control reversing valve 12, and the connection point is between the first throttle valve 16 and the second throttle valve 17; the other end of the safety oil path 25 is connected to the internal oil drain path 23 at a position after the connection position of the oil outlet of the electric proportional pressure compensator 14. The valve spool of the hydraulic control reversing valve 12 moves in small amplitudes continuously in the valve; when the valve spool is at a specific position, the hydraulic control reversing valve 12 is closed, making the piston chamber of the servo cylinder 13 a dead space, i.e., the oil path between the piston chamber and the hydraulic control reversing valve 12 becomes a rigid oil path. It should be noted that the first throttle valve, the second throttle valve and the third throttle valve may be replaced with damping holes.
As shown in
The working principle of the rotation speed control system for a heat dissipation device of a construction machinery in the basic embodiments of the present disclosure is described below.
As shown in
Thus, as shown in
Preferably, the oil tank 35 is a closed-type oil tank, to prevent impurities from mixed into the hydraulic oil and keep the hydraulic oil clean.
Preferably, a probe of the temperature sensor 31 is arranged at the bottom of the oil tank 35 to acquire the real-time oil temperature of the hydraulic oil. Of course, the probe of the temperature sensor 31 may be arranged at other positions as required according to the design.
An overflow valve 36 is provided between the main oil inflow path 43 and the main oil return path 44, to control the pressure in the main oil inflow path 43 and control excessive oil to flow back to the oil tank 35.
Preferably, the main reversing valve 37 is a solenoid directional control valve that is electrically connected to the controller 15, and the controller 15 can control the main reversing valve 37 to perform reversing, so that the fan motor 33 is switched to rotate in the normal direction or reversed direction.
A check valve is connected in parallel between the two ends of the fan motor 33, and can replenish oil to the second working oil port B of the fan motor 33 when the fan motor 33 rotates in the reversed direction. The fan motor 33 rotates in the normal direction in the normal state; when the fan motor 33 is switched to rotate in the reversed direction, the disturbances to the hydraulic oil in the system are higher, so as to prevent an excessive pressure at the second working oil port B of the fan motor 33.
A construction machinery disclosed in the present disclosure comprises a heat radiator for cooling the hydraulic oil and the rotation speed control system for a heat dissipation device of a construction machinery according to any of the above technical schemes, wherein a fan motor 33 can drive the fan 32 to rotate to cool the heat radiator. Since the construction machinery disclosed in the present disclosure employs all technical schemes in the above embodiments, it at least has all beneficial effects brought by the technical schemes in the above embodiments.
While the present disclosure is described above in detail in some preferred embodiments with reference to the accompanying drawings, the present disclosure is not limited to those embodiments. Various simple variations may be made to the technical scheme in the present disclosure, including combinations of the specific technical features in any appropriate form, within the scope of the technical ideal of the present disclosure. To avoid unnecessary repetition, various possible combinations are not described specifically in the present disclosure. However, such simple variations and combinations shall also be deemed as having been disclosed and falling in the scope of protection of the present disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202011065237.X | Sep 2020 | CN | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN2021/119804 | 9/23/2021 | WO |
