Oil temperature control method, oil temperature control system, and working machine

Abstract

The invention belongs to the technical field of engineering machinery and provides an oil temperature control method, an oil temperature control system and an operation machine. The oil temperature control method comprises the steps that the oil temperature of hydraulic oil is obtained; when the oil temperature of the hydraulic oil is not in the preset temperature interval, the target displacement of the cooling pump is adjusted according to the contrast relation between the oil temperature and the displacement in the preset mapping table, and meanwhile, the throttling element is closed, so that the cooling pump pumps the hydraulic oil to the motor according to the target displacement to drive the fan to rotate; and under the condition that the cooling pump works for the preset duration at the target displacement, the opening degree of the throttling element is adjusted according to the subordination relation between the oil temperature of the hydraulic oil and the preset temperature interval so as to adjust the oil temperature of the hydraulic oil. According to the method, waste of system pressure can be effectively reduced, and oil temperature dynamic regulation and control can be achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of engineering machinery, and in particular relates to an oil temperature control method, an oil temperature control system and an operating machine. Background Art

[0002] Some large-scale engineering equipment (such as excavators over 40 tons, super-large cranes, etc.) need to set up independent oil temperature control methods for their hydraulic systems. Existing oil temperature control methods mainly include cooling pumps, coolers, motors and fans. The motor drives the fan to blow air to the cooler, so that the hydraulic oil flowing through the cooler can be quickly cooled.

[0003] Existing oil temperature control methods generally achieve displacement regulation of the motor and fan by connecting a throttle valve in series between the cooling pump and the motor. When such a system is in operation, the cooling pump always outputs at maximum displacement. The flow output by the cooling pump is throttled by the throttle valve and then transmitted to the motor, which will cause a very large pressure loss and lead to serious heating of the system. At the same time, this flow regulation method cannot achieve precise regulation of the fan displacement. Summary of the invention

[0004] In view of the above-mentioned defects or shortcomings, the present invention provides an oil temperature control method, an oil temperature control system and an operating machine, aiming to solve the technical problems of the existing oil temperature control method, such as high energy consumption, severe heat generation and inability to accurately adjust the fan speed.

[0005] To achieve the above object, the present invention provides an oil temperature control method, which is applied to an oil temperature control system. The system includes a controller, a cooling pump, a motor, a fan and a throttling element. The controller is respectively connected to the cooling pump and the throttling element for communication. The motor is used to drive the fan to rotate. The cooling pump and the motor constitute a fan drive circuit. The throttling element has an adjustable opening and is arranged in parallel with the motor between the oil inlet and the oil return circuit of the fan drive circuit.

[0006] Oil temperature control methods include:

[0007] S100: obtaining the oil temperature of the hydraulic oil;

[0008] S200: When the temperature of the hydraulic oil is not within the preset temperature range, the target displacement of the cooling pump is adjusted according to the comparison relationship between the oil temperature and the displacement in the preset mapping table, and the throttling element is closed at the same time, so that the cooling pump pumps the hydraulic oil to the motor according to the target displacement to drive the fan to rotate;

[0009] S300: When the cooling pump operates at a target displacement for a preset time, the opening of the throttling element is adjusted according to a subordinate relationship between the oil temperature of the hydraulic oil and a preset temperature range to adjust the oil temperature of the hydraulic oil.

[0010] In an embodiment of the present invention, in step S300, adjusting the opening of the throttling element to adjust the temperature of the hydraulic oil according to the subordinate relationship between the temperature of the hydraulic oil and the preset temperature range specifically includes:

[0011] S300a: If the temperature of the hydraulic oil is within the preset temperature range, the throttling element is controlled to remain closed, and the cooling pump is controlled to operate at the current displacement to keep the hydraulic oil at the current temperature;

[0012] S300b: If the temperature of the hydraulic oil is not within the preset temperature range, at least one of the displacement of the cooling pump and the opening of the throttling element is adjusted to correspondingly increase or decrease the oil temperature.

[0013] In an embodiment of the present invention, step S300b: if the oil temperature of the hydraulic oil is not within the preset temperature range, adjusting at least one of the displacement of the cooling pump and the opening of the throttling element to increase or decrease the oil temperature accordingly, specifically includes:

[0014] S300b-1: if the oil temperature of the hydraulic oil is higher than the first preset temperature, the target displacement of the cooling pump is readjusted according to the increased oil temperature, and the throttling element is kept closed, so that the cooling pump pumps the hydraulic oil to the motor according to the readjusted target displacement, and drives the fan to increase the speed to reduce the oil temperature;

[0015] S300b-2: If the temperature of the hydraulic oil is lower than the second preset temperature, the cooling pump is controlled to maintain the current displacement operation, and the throttling element is controlled to change the opening to drive the fan to reduce the speed to increase the oil temperature until the temperature of the hydraulic oil is stabilized in the preset temperature range and the current opening of the throttling element is maintained.

[0016] The first preset temperature and the second preset temperature are respectively the upper limit and the lower limit of the preset temperature range.

[0017] In an embodiment of the present invention, step S200: when the oil temperature of the hydraulic oil is not within the preset temperature range, according to the control relationship between the oil temperature and the displacement in the preset mapping table, the target displacement of the cooling pump is adjusted, and the throttling element is closed at the same time, so that the cooling pump pumps the hydraulic oil to the motor according to the target displacement, and drives the fan to rotate, specifically including:

[0018] S201: If the temperature of the hydraulic oil is lower than the third preset temperature, the cooling pump is controlled to output at a minimum displacement, and the throttling element is closed at the same time, so that the cooling pump pumps the hydraulic oil to the motor at the minimum displacement to drive the fan to rotate;

[0019] The third preset temperature is lower than the lower limit of the preset temperature range.

[0020] In an embodiment of the present invention, step S300: when the cooling pump operates at a target displacement for a preset time, adjusting the opening of the throttling element according to the subordinate relationship between the oil temperature of the hydraulic oil and the preset temperature range to adjust the oil temperature of the hydraulic oil, includes:

[0021] S301: When the cooling pump operates at the minimum displacement for a preset time, if the temperature of the hydraulic oil is lower than the lower limit of the preset temperature range, the cooling pump is controlled to maintain the current displacement and the throttling element is controlled to change the opening to adjust the temperature of the hydraulic oil until the motor stops completely.

[0022] To achieve the above-mentioned purpose, the present invention also provides an oil temperature control system, wherein the oil temperature control system includes a fan drive circuit, a fan, a throttling element and a controller, the fan drive circuit includes an oil inlet circuit, an oil return circuit, a cooling pump as a power input, and a motor as an actuator, the fan is transmission-connected to the motor, the throttling element is connected between the oil inlet circuit and the oil return circuit and is arranged in parallel with the motor, the controller is electrically connected to the cooling pump and the throttling element, respectively, and the controller is used to execute the oil temperature control method described above.

[0023] In an embodiment of the present invention, the oil temperature control system also includes a one-way oil supply circuit, which is arranged in parallel with the cooling motor and connected between the oil inlet circuit and the oil return circuit. A one-way valve is provided on the one-way oil supply circuit, and the one-way valve is configured to be turned on when the hydraulic oil flows from the oil return circuit to the oil inlet circuit and to be turned off in the reverse direction.

[0024] In an embodiment of the present invention, a reversing valve is also provided between the cooling pump and the motor, and the reversing valve is used to selectively direct the hydraulic oil in the oil inlet circuit to one of the forward oil inlet and the reverse oil inlet of the motor, and to connect the other of the forward oil inlet and the reverse oil inlet to the return oil circuit.

[0025] In an embodiment of the present invention, the oil temperature control system further comprises a temperature sensor, which is communicatively connected to the controller and is used to detect the oil temperature of the hydraulic oil.

[0026] To achieve the above object, the present invention further provides a working machine, wherein the working machine includes the oil temperature control system described above.

[0027] Through the above technical solution, the oil temperature control method provided by the embodiment of the present invention has the following beneficial effects:

[0028] This method can adjust the fan displacement to be close to the actual required heat dissipation rate of the hydraulic oil by first adjusting the displacement of the cooling pump according to the temperature of the hydraulic oil. Furthermore, when necessary, by changing the opening of the throttling element, the flow rate of the variable pump to the motor can be partially returned to the oil return line through the throttling element, thereby achieving further fine adjustment of the motor displacement (fan speed). After the cooling pump works at the target speed corresponding to the oil temperature, since the fan speed (displacement of the cooling pump) is close to the actual required heat dissipation rate of the hydraulic oil, after the throttling element is adjusted, at most only a small part of the hydraulic oil is throttled through the throttling element, which effectively reduces the waste of system pressure. Furthermore, this method can adjust the displacement of the cooling pump and the opening of the throttling element based on the change of the oil temperature of the hydraulic oil to achieve dynamic oil temperature control of the system.

[0029] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings are used to provide an understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention, but do not constitute a limitation of the present invention. In the accompanying drawings:

[0031] Figure 1 is a general flow chart of the oil temperature control method according to an embodiment of the present invention;

[0032] Figure 2 is a specific step diagram of step S300 according to an embodiment of the present invention;

[0033] Figure 3 is a specific step diagram of step S300b according to an embodiment of the present invention;

[0034] Figure 4 is a hydraulic connection principle diagram of an oil temperature control system according to an embodiment of the present invention;

[0035] Figure 5 4 is a control principle diagram of an oil temperature control system according to an embodiment of the present invention.

[0036] Description of Reference Numerals

[0037] 11. Oil inlet circuit; 12. Oil return circuit; 13. Cooling pump; 14. Motor; 2. Fan; 3. Throttling element; 4. One-way oil supply circuit; 5. Safety overflow circuit; 6. Reversing valve. DETAILED DESCRIPTION

[0038] The specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0039] The oil temperature control method and the oil temperature control system of the present invention will be described below with reference to the accompanying drawings.

[0040] like Figure 4 and Figure 5 As shown, the present invention provides an oil temperature control system, which is mainly used for cooling the hydraulic oil of the hydraulic system of some large-scale working machinery. The oil temperature control system includes a fan drive circuit, a fan 2 and a throttling element 3.

[0041] The fan drive circuit includes an oil inlet 11, an oil return 12, a cooling pump 13 as a power input, and a motor 14 as an actuator. When the cooling pump 13 is working, the hydraulic oil output will enter the oil inlet of the motor 14 through the oil inlet 11, then flow out from the oil outlet of the motor 14, and flow back to the oil tank or the oil suction port of the cooling pump 13 through the oil return 12.

[0042] The fan 2 is drivingly connected to the motor 14 .

[0043] The throttling element 3 is connected between the oil inlet 11 and the oil return 12 and is arranged in parallel with the motor 14. The opening of the throttling element 3 can be adjusted between 0-100%. When the opening of the throttling element 3 is 0, the throttling element 3 is in a cut-off state. When the opening of the throttling element 3 is 100%, the throttling element 3 is in a maximum opening state. The flow rate of the maximum opening of the throttling element 3 can be greater than the maximum displacement of the cooling pump 13. When the throttling element 3 completely bypasses the motor 14, the throttling element can be in a non-maximum opening state.

[0044] The controller is electrically connected to the cooling pump 13 and the throttling element 3 respectively, and is used to adjust the displacement of the cooling pump 13 and the opening of the throttling element 3 according to different oil temperatures of the hydraulic oil.

[0045] The larger the displacement outputted by the cooling pump 13 to the motor 14, the higher the speed of the fan 2. By adjusting the displacement of the cooling pump 13, the speed of the fan 2 can be quickly adjusted. By changing the opening of the throttling element 3, the flow outputted by the variable pump to the motor 14 can be partially returned to the oil return line 12 through the throttling element 3, thereby achieving further fine adjustment of the displacement of the motor 14. Through the cooperation of the variable pump and the throttling element 3, the speed of the motor 14 and the fan 2 can be adjusted without dead zone and the speed can be accurately controlled.

[0046] Furthermore, if Figure 1 As shown, the present invention further provides an oil temperature control method, which is applied to the oil temperature control system as described above, and the oil temperature control method includes:

[0047] S100: obtaining the oil temperature of the hydraulic oil;

[0048] S200: When the temperature of the hydraulic oil is not within the preset temperature range, the target displacement of the cooling pump is adjusted according to the comparison relationship between the oil temperature and the displacement in the preset mapping table, and the throttling element is closed at the same time, so that the cooling pump pumps the hydraulic oil to the motor according to the target displacement to drive the fan to rotate;

[0049] S300: When the cooling pump operates at a target displacement for a preset time, the opening of the throttling element is adjusted according to a subordinate relationship between the oil temperature of the hydraulic oil and a preset temperature range to adjust the oil temperature of the hydraulic oil.

[0050] This method can adjust the displacement of the fan 2 to be close to the actual required heat dissipation rate of the hydraulic oil by first adjusting the displacement of the cooling pump 13 according to the temperature of the hydraulic oil. Furthermore, when necessary, by changing the opening of the throttling element 3, the flow of the variable pump to the motor 14 can be partially returned to the oil return line 12 through the throttling element 3, thereby achieving further fine adjustment of the displacement of the motor 14 (the speed of the fan 2). After the cooling pump 13 works at the target speed corresponding to the oil temperature, since the speed of the fan 2 (the displacement of the cooling pump 13) is close to the actual required heat dissipation rate of the hydraulic oil, after the throttling element 3 is adjusted, at most only a small part of the hydraulic oil is throttled through the throttling element 3, which effectively reduces the waste of system pressure. Furthermore, this method can adjust the displacement of the cooling pump 13 and the opening of the throttling element 3 based on the change of the oil temperature of the hydraulic oil, so as to achieve dynamic oil temperature control of the system.

[0051] It is understandable that, in some cases, if the heat dissipation requirement of the hydraulic oil can be matched by adjusting the displacement of the cooling pump 13 , the throttling element 3 may not be involved in the work.

[0052] like Figure 2 As shown, in an embodiment of the present invention, before adjusting the displacement of the cooling pump 13 according to the control relationship between the oil temperature and the target displacement in the preset mapping table or during the adjustment of the cooling pump, the throttling element 3 needs to be controlled to be fully closed.

[0053] Since the control priority of the cooling pump 13 is higher than that of the throttling element 3, the present method needs to ensure that the throttling element 3 is reset to the closed state before adjusting the displacement of the cooling pump 13 according to the temperature of the hydraulic oil each time, so as to avoid the throttling element 3 interfering with the regulation of the cooling pump 13.

[0054] like Figure 2 As shown, in an embodiment of the present invention, in step S300: according to the subordinate relationship between the oil temperature of the hydraulic oil and the preset temperature range, adjusting the opening of the throttling element to adjust the oil temperature of the hydraulic oil specifically includes:

[0055] S300a: If the temperature of the hydraulic oil is within the preset temperature range, the throttling element is controlled to remain closed, and the cooling pump is controlled to operate at the current displacement to keep the hydraulic oil at the current temperature;

[0056] S300b: If the temperature of the hydraulic oil is not within the preset temperature range, at least one of the displacement of the cooling pump and the opening of the throttling element is adjusted to correspondingly increase or decrease the oil temperature.

[0057] Specifically, Figure 3 As shown, in an embodiment of the present invention, step S300b: if the oil temperature of the hydraulic oil is not within the preset temperature range, at least one of the displacement of the cooling pump and the opening of the throttling element is adjusted to increase or decrease the oil temperature accordingly, specifically including:

[0058] S300b-1: if the oil temperature of the hydraulic oil is higher than the first preset temperature, the target displacement of the cooling pump is readjusted according to the increased oil temperature, and the throttling element is kept closed, so that the cooling pump pumps the hydraulic oil to the motor according to the readjusted target displacement, and drives the fan to increase the speed to reduce the oil temperature;

[0059] S300b-2: If the temperature of the hydraulic oil is lower than the second preset temperature, the cooling pump is controlled to maintain the current displacement operation, and the throttling element is controlled to change the opening to drive the fan to reduce the speed to increase the oil temperature until the temperature of the hydraulic oil is stabilized in the preset temperature range and the current opening of the throttling element is maintained.

[0060] The first preset temperature and the second preset temperature are respectively the upper limit and the lower limit of the preset temperature range.

[0061] The comparison relationship between oil temperature and target displacement in the preset mapping table refers to the comparison data finally obtained by testing hydraulic oils of different oil temperatures when the equipment is operating at laboratory ambient temperature, and determining how large the displacement of the cooling pump 13 is required to supply oil to the motor 14 to ensure that the oil temperature remains within the preset temperature range.

[0062] Due to the change of actual ambient temperature, when the hydraulic pump works at the target displacement corresponding to the oil temperature, excessive heat dissipation or insufficient heat dissipation rate may occur. For example, when the equipment works in an environment of more than ten degrees below zero, the temperature is quite different from the laboratory ambient temperature. Although the oil temperature can be raised to 20 degrees by the hydraulic oil heater, if the cooling pump 13 works at the target displacement corresponding to the oil temperature of 20 degrees, it is easy to cause the system oil temperature to be too low.

[0063] To this end, the method ensures that the rotation speed of the fan 2 matches the actual required heat dissipation rate of the hydraulic oil by selecting and controlling the throttling element 3 to intervene at an appropriate time.

[0064] When the speed of the fan 2 can be matched with the actual required heat dissipation rate of the hydraulic oil by adjusting the displacement of the cooling pump 13 alone, the throttling element 3 can be in a cut-off state and not involved in the work. When it is difficult to adjust the speed of the fan 2 to match the actual required heat dissipation rate of the hydraulic oil by adjusting the displacement of the cooling pump 13, the displacement of the motor 14 can be fine-tuned by further adjusting the opening of the throttling element 3 to achieve the matching of the two.

[0065] Take the case where the initial oil temperature of the cooling pump 13 is higher than the preset temperature range as an example.

[0066] After the cooling pump 13 operates at the target displacement corresponding to the oil temperature for a preset time, if the temperature of the hydraulic oil drops and remains within the preset temperature range, the cooling pump 13 is controlled to continue operating at the current displacement and the throttling element 3 is not operated.

[0067] After the cooling pump 13 operates at the target displacement corresponding to the oil temperature for a preset time period, if the oil temperature of the hydraulic oil still exceeds the first preset temperature, the displacement of the cooling pump 13 is changed again according to the increased oil temperature.

[0068] After the cooling pump 13 operates at a target displacement corresponding to the oil temperature for a preset time period, if the temperature of the hydraulic oil is lower than a second preset temperature, the throttling element 3 is controlled to increase its opening.

[0069] In the process of adjusting the displacement of the cooling pump 13, it is possible that when the cooling pump 13 increases the displacement a little, the oil temperature of the hydraulic oil will continue to rise until it exceeds the preset temperature range, and when the cooling pump 13 reduces the displacement a little, the oil temperature of the hydraulic oil will continue to decrease until it is lower than the preset temperature range. At this time, the flow rate of the cooling pump 13 to the motor 14 can be fine-tuned by adjusting the opening of the throttling element 3.

[0070] like Figure 1 As shown, in an embodiment of the present invention, step S200: when the oil temperature of the hydraulic oil is not within the preset temperature range, according to the control relationship between the oil temperature and the displacement in the preset mapping table, the target displacement of the cooling pump is adjusted, and the throttling element is closed at the same time, so that the cooling pump pumps the hydraulic oil to the motor according to the target displacement, and drives the fan to rotate, specifically including:

[0071] S201: If the temperature of the hydraulic oil is lower than the third preset temperature, the cooling pump is controlled to output at a minimum displacement, and the throttling element is closed at the same time, so that the cooling pump pumps the hydraulic oil to the motor at the minimum displacement to drive the fan to rotate;

[0072] The third preset temperature is lower than the lower limit of the preset temperature range.

[0073] The third preset temperature is a threshold for determining a cold environment. When the oil temperature is lower than the third preset temperature, it means that the system is in a cold environment.

[0074] This regulatory process mainly occurs in cold environments.

[0075] In a cold environment, the equipment is started and the cooling pump 13 starts to run. When it is determined that the operating machine is in a cold environment, that is, when it is confirmed that the oil temperature of the hydraulic oil is lower than the third preset temperature, the method will first control the throttling element 3 to remain closed, and then adjust the displacement of the cooling pump 13 to the minimum so that the cooling pump 13 outputs at the minimum displacement. Wait for a preset time, and during the preset waiting time, monitor the change of the oil temperature. If the oil temperature rises and then remains within the preset temperature range, continue to control the cooling pump 13 to run in the current state. If the oil temperature rises and exceeds the preset temperature range, the displacement of the cooling pump 13 is increased according to the different oil temperatures of the hydraulic oil.

[0076] For operating machinery, the cooling rate requirements of hydraulic oil vary when working in different regions and seasons. Especially when the equipment is working in the north in winter, the initial temperature of the hydraulic oil may be more than ten degrees below zero or even dozens of degrees. At this time, even if the cooling pump 13 is running at the lowest displacement, the air volume generated by the fan 2 may still cause the hydraulic oil temperature to be too low. If the fan 2 is controlled to stop completely, the oil temperature may rise rapidly. That is, the method of adjusting the displacement of the motor 14 by changing the displacement of the cooling pump 13 has a blind spot in speed regulation.

[0077] For this reason, Figure 1 As shown, in an embodiment of the present invention, step S300: when the cooling pump works at a target displacement for a preset time, adjusting the opening of the throttling element according to the subordinate relationship between the oil temperature of the hydraulic oil and the preset temperature range to adjust the oil temperature of the hydraulic oil, includes:

[0078] S301: When the cooling pump operates at the minimum displacement for a preset time, if the temperature of the hydraulic oil is lower than the lower limit of the preset temperature range, the cooling pump is controlled to maintain the current displacement and the throttling element is controlled to change the opening to adjust the temperature of the hydraulic oil until the motor stops completely.

[0079] After controlling the cooling pump 13 to output at the minimum displacement, if the oil temperature rises only slightly or even drops, it means that even if the cooling pump 13 outputs at the minimum displacement, the current heat dissipation rate is still too fast for the hydraulic oil. At this time, the throttling element 3 can be controlled to increase its opening.

[0080] Furthermore, step S301 can be used for oil temperature control in an extremely cold environment. In an extremely cold environment, this method can further reduce the heat dissipation rate of the hydraulic oil by adjusting the opening of the throttling element 3, thereby ensuring that the equipment works normally in an extremely cold environment.

[0081] It is understandable that when adjusting the opening of the throttling element 3 in an extremely cold environment, the throttling element 3 is allowed to completely bypass the motor 14, that is, in an extremely cold environment, the fan 2 is allowed to stop completely.

[0082] like Figure 4 As shown, in an embodiment of the present invention, the oil temperature control system also includes a one-way oil supply circuit 4, which is arranged in parallel with the cooling motor 14 and connected between the oil inlet circuit 11 and the oil return circuit 12. A one-way valve is provided on the one-way oil supply circuit 4, and the one-way valve is configured to be conductive when the hydraulic oil flows from the oil return circuit 12 to the oil inlet circuit 11 and to be blocked in the reverse direction.

[0083] When the cooling pump 13 stops, the fan 2 will drive the motor 14 to continue rotating due to inertia. The continued operation of the motor 14 will cause one of the oil ports of the motor 14 to suck oil from the oil inlet 11, and the other oil port to pump oil to the oil return 12. In order to realize the slow stop function of the fan 2, a one-way oil replenishment circuit 4 can be set between the oil inlet 11 and the oil return 12, so that when the cooling pump 13 stops, an independent circuit is formed between the oil inlet 11, the oil return 12, the motor 14, and the one-way oil replenishment circuit 4 to ensure that the motor 14 can operate in a floating manner.

[0084] like Figure 4 As shown, in the embodiment of the present invention, a reversing valve 6 is further provided between the cooling pump 13 and the motor 14 in the oil temperature control system. The reversing valve 6 is used to selectively direct the hydraulic oil of the oil inlet 11 to one of the forward oil inlet and the reverse oil inlet of the motor 14, and to connect the other of the forward oil inlet and the reverse oil inlet to the return oil circuit 12. When the hydraulic oil of the oil inlet 11 enters from the forward oil inlet, the reverse oil inlet is connected to the return oil circuit 12, and the motor 14 rotates forward. When the hydraulic oil of the oil inlet 11 enters from the reverse oil inlet, the forward oil inlet is connected to the return oil circuit 12, and the motor 14 rotates reversely.

[0085] like Figure 4 As shown, in an embodiment of the present invention, the reversing valve 6 is further provided with a shutdown stop valve position, which is configured to shut off the two oil ports of the motor 14 and connect the oil inlet circuit 11 and the oil return circuit 12.

[0086] like Figure 4 As shown, in an embodiment of the present invention, the oil temperature control method further includes a safety overflow circuit 5, which is arranged in parallel with the motor 14 and connected between the oil inlet circuit 11 and the oil return circuit 12. By setting the safety overflow circuit 5, the maximum working pressure of the oil temperature control system can be set.

[0087] like Figure 4 and Figure 5 As shown, in an embodiment of the present invention, the oil temperature control system further includes a temperature sensor, which is communicatively connected to the controller and is used to detect the oil temperature of the hydraulic oil.

[0088] In an embodiment of the present invention, a heating rod may be provided in the oil tank of the operating machine, and when the operating machine is started under cold conditions, the heating rod may be controlled to run for a certain period of time before the machine is operated.

[0089] In the embodiment of the present invention, starting refers to starting an engine in a working machine, and working refers to the action of an actuator in the machine.

[0090] To achieve the above object, the present invention further provides an operating machine, wherein the operating machine includes the oil temperature control system described above. The operating machine may be an excavator, a truck crane, etc. Since the operating machine adopts all the technical solutions of the above embodiments, it at least has the beneficial effects brought by the above embodiments, which will not be repeated here.

[0091] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0092] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0093] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0094] Although the embodiments of the present invention have been described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. An oil temperature control method, characterized in that: The method is applied to an oil temperature control system, the system comprising a controller, a cooling pump (13), a motor (14), a fan (2) and a throttling element (3), the controller being respectively connected to the cooling pump (13) and the throttling element (3) in communication, the motor (14) being used to drive the fan (2) to rotate, the cooling pump (13) and the motor (14) forming a fan drive circuit, the throttling element (3) having an adjustable opening and being arranged in parallel with the motor (14) between an oil inlet circuit (11) and an oil return circuit (12) of the fan (2) drive circuit; The oil temperature control method comprises: Get the oil temperature of hydraulic oil; When the temperature of the hydraulic oil is not within a preset temperature range, the target displacement of the cooling pump (13) is adjusted according to the comparison relationship between the oil temperature and the displacement in a preset mapping table, and the throttling element is closed at the same time, so that the cooling pump (13) pumps the hydraulic oil to the motor according to the target displacement, driving the fan to rotate; When the cooling pump (13) operates at the target displacement for a preset time, the opening of the throttling element (3) is adjusted according to the subordinate relationship between the oil temperature of the hydraulic oil and the preset temperature range to adjust the oil temperature of the hydraulic oil.

2. The oil temperature control method according to claim 1, characterized in that: According to the subordinate relationship between the oil temperature of the hydraulic oil and the preset temperature range, the opening of the throttling element (3) is adjusted to adjust the oil temperature of the hydraulic oil, specifically including: If the temperature of the hydraulic oil is within a preset temperature range, the throttling element (3) is controlled to remain closed, and the cooling pump is controlled to operate at a current displacement so that the hydraulic oil maintains a current temperature; If the oil temperature of the hydraulic oil is not within the preset temperature range, at least one of the displacement of the cooling pump and the opening of the throttling element is adjusted to correspondingly increase or decrease the oil temperature.

3. The oil temperature control method according to claim 2, characterized in that: If the oil temperature of the hydraulic oil is not within the preset temperature range, at least one of the displacement of the cooling pump and the opening of the throttling element is adjusted to correspondingly increase or decrease the oil temperature, specifically including: If the oil temperature of the hydraulic oil is higher than a first preset temperature, the target displacement of the cooling pump (13) is readjusted according to the increased oil temperature, while keeping the throttling element closed, so that the cooling pump (13) pumps the hydraulic oil to the motor according to the readjusted target displacement, and drives the fan to increase the speed to reduce the oil temperature; If the temperature of the hydraulic oil is lower than a second preset temperature, the cooling pump is controlled to maintain the current displacement operation, and the throttling element (3) is controlled to change the opening degree, so as to drive the fan to reduce the rotation speed to increase the oil temperature, until the temperature of the hydraulic oil is stabilized in the preset temperature range and the current opening degree of the throttling element (3) is maintained; The first preset temperature and the second preset temperature are respectively the upper limit and the lower limit of the preset temperature range.

4. The oil temperature control method according to claim 1, characterized in that: When the oil temperature of the hydraulic oil is not within a preset temperature range, the target displacement of the cooling pump (13) is adjusted according to the comparison relationship between the oil temperature and the displacement in a preset mapping table, and the throttling element is closed at the same time, so that the cooling pump (13) pumps the hydraulic oil to the motor according to the target displacement, driving the fan to rotate, specifically comprising: If the temperature of the hydraulic oil is lower than a third preset temperature, the cooling pump (13) is controlled to output at a minimum displacement, and the throttling element is closed at the same time, so that the cooling pump (13) pumps the hydraulic oil to the motor at the minimum displacement to drive the fan to rotate; The third preset temperature is lower than a lower limit value of the preset temperature range.

5. The oil temperature control method according to claim 4, characterized in that: When the cooling pump (13) operates at the target displacement for a preset time, adjusting the opening of the throttling element (3) according to the subordinate relationship between the oil temperature of the hydraulic oil and a preset temperature range to adjust the oil temperature of the hydraulic oil, comprising: When the cooling pump (13) operates at a minimum displacement for a preset time, if the temperature of the hydraulic oil is lower than a lower limit of the preset temperature range, the cooling pump is controlled to maintain operation at the current displacement, and the throttling element (3) is controlled to change its opening to adjust the temperature of the hydraulic oil until the motor (14) stops completely.

6. An oil temperature control system, characterized in that: The oil temperature control system comprises: A fan driving circuit includes an oil inlet circuit (11), an oil return circuit (12), a cooling pump (13) as a power input, and a motor (14) as an actuator; A fan (2) is drivingly connected to the motor (14); A throttling element (3) connected between the oil inlet passage (11) and the oil return passage (12) and arranged in parallel with the motor (14); A controller is electrically connected to the cooling pump (13) and the throttling element (3), respectively, and the controller is used to execute the oil temperature control method according to any one of claims 1 to 5.

7. The oil temperature control system according to claim 6, characterized in that: The oil temperature control system further comprises a one-way oil supply circuit (4), the one-way oil supply circuit (4) being arranged in parallel with the motor (14) and connected between the oil inlet circuit (11) and the oil return circuit (12), the one-way oil supply circuit (4) being provided with a one-way valve, the one-way valve being configured to be conductive when hydraulic oil flows from the oil return circuit (12) to the oil inlet circuit (11) and to be blocked in the reverse direction.

8. The oil temperature control system according to claim 6, characterized in that: A reversing valve (6) is also provided between the cooling pump (13) and the motor (14), and the reversing valve (6) is used to selectively direct the hydraulic oil of the oil inlet circuit (11) to one of the forward oil inlet and the reverse oil inlet of the motor (14), and to connect the other of the forward oil inlet and the reverse oil inlet to the oil return circuit (12).

9. The oil temperature control system according to claim 6, characterized in that: The oil temperature control system further includes a temperature sensor, which is communicatively connected to the controller and is used to detect the oil temperature of the hydraulic oil.

10. A working machine, characterized in that: Comprising the oil temperature control system according to any one of claims 6 to 9.

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