Hydraulic oil preheating system for load sensing system

Abstract

This invention discloses a hydraulic oil preheating system suitable for load-sensitive systems, comprising a hydraulic pump, a first variable cylinder and a second variable cylinder, a displacement control valve, a first pressure setting valve, a second pressure setting valve, a flow divider valve, a first directional valve, a second directional valve, a damper, and a multi-way directional valve. The outlet of the hydraulic pump is connected to the inlets of the first pressure setting valve, the flow divider valve, the first directional valve, the displacement control valve, and the multi-way directional valve, and is also connected to the control port of the displacement control valve and the spring chamber of the first variable cylinder. The spring chamber of the displacement control valve is connected to the outlet of the first directional valve, the spring chamber of the flow divider valve, and the inlet of the second directional valve. The large chamber of the second variable cylinder is connected to the outlet of the displacement control valve. The damper is located between the inlet of the second directional valve and the load feedback port of the multi-way directional valve. The outlets of the first pressure setting valve, the second pressure setting valve, and the flow divider valve are all connected to the return oil tank. This invention can increase the hydraulic oil temperature in low-temperature environments, enabling the hydraulic system to reach its optimal operating state.

Description

Technical Field

[0001] This invention belongs to the field of engineering machinery technology, and specifically relates to a hydraulic oil preheating system suitable for load-sensitive systems. Background Technology

[0002] Cranes operating in extremely cold environments require preheating of their hydraulic systems. If the appropriate temperature isn't reached, the sealing effectiveness of the seals will be compromised, reducing their lifespan and potentially causing damage and leaks. The conventional hydraulic system preheating process is as follows: after the engine starts, the crane is in standby mode. Hydraulic oil flows through the main pump to the diverter valve in the main valve and then back to the tank. During this process, the hydraulic oil generates heat by being throttled through the main valve, thus preheating the system. However, for load-sensitive systems, in standby mode, the pump only outputs hydraulic oil sufficient to cover its own leakage. Throttling through the main valve in this process leads to a prolonged preheating time. Insufficient preheating time can induce failure of the valve's sealing elements, compromising their sealing performance, leading to later damage and leaks, reduced reliability, and increased maintenance costs.

[0003] Chinese utility model patent CN217518999U discloses a preheating system and engineering machinery, such as Figure 1 As shown, the system includes: a hydraulic oil tank with a cavity; a temperature sensor located in the hydraulic oil tank; a pump body connected to the hydraulic oil tank; a preheating device located in the hydraulic oil tank; and a controller electrically connected to the temperature sensor to obtain temperature information about the hydraulic oil from the temperature sensor. The controller is connected to the pump body and the preheating device, and controls the pump body and / or the preheating device to preheat the hydraulic oil. This solution directly heats the hydraulic oil by adding a heating device inside the oil tank. The heating device requires an external power source. One option is to use a vehicle battery. However, prolonged use of the vehicle battery to heat the hydraulic oil can reduce the battery capacity, leading to battery depletion and insufficient current to meet the large current required for engine starting, thus affecting engine starting. Furthermore, the capacity of the vehicle battery limits the ability to widely use the heating components to preheat other systems. Another option is to use an external power source, but this method is significantly affected by the working environment. Summary of the Invention

[0004] To address the aforementioned issues, this invention proposes a hydraulic oil preheating system suitable for load-sensitive systems. By using an onboard engine to drive a hydraulic pump, the hydraulic oil is circulated and heated, which can rapidly increase the hydraulic oil temperature in low-temperature environments, enabling the hydraulic system to quickly reach its optimal operating state, thereby improving the reliability of hydraulic components and the safety of crane operations.

[0005] To achieve the above-mentioned technical objectives and effects, the present invention is implemented through the following technical solution:

[0006] A hydraulic oil preheating system suitable for load-sensitive systems includes a load-sensitive pump, a displacement control valve, a first pressure setting valve, a second pressure setting valve, a flow divider valve, a first directional valve, a second directional valve, a damping valve, and a multi-way directional valve; the load-sensitive pump includes a hydraulic pump, a first variable cylinder, and a second variable cylinder.

[0007] The outlet of the hydraulic pump is connected to the inlet of the first pressure setting valve, the flow divider valve, the first directional valve, the displacement control valve, and the multi-way directional valve, respectively, and is also connected to the control port of the displacement control valve and the spring chamber of the first variable cylinder.

[0008] The spring chamber of the displacement control valve is connected to the oil outlet of the first reversing valve, the spring chamber of the flow divider valve, and the oil inlet of the second reversing valve, respectively.

[0009] The large chamber of the second variable cylinder is connected to the oil outlet of the displacement control valve;

[0010] The damper is located between the oil inlet of the second directional valve and the load feedback port of the multi-way directional valve.

[0011] The oil outlets of the first pressure setting valve, the second pressure setting valve, and the diverter valve are all connected to the return oil tank.

[0012] Optionally, the volume of the first variable cylinder is larger than the volume of the second variable cylinder.

[0013] Optionally, when the first and second directional valves are in the off position, the hydraulic oil pumped by the load-sensitive pump causes the displacement control valve to switch through the control oil circuit, making the cavities of the first and second variable cylinders in the load-sensitive pump connected. Under the effect of the area difference of the variable cylinders, the load-sensitive pump is in a small displacement state. The hydraulic oil pumped by the load-sensitive pump, after meeting its own leakage requirements, will cause the hydraulic oil pressure at the outlet of the load-sensitive pump to increase. When it reaches the set value of the diverter valve, it flows back to the oil tank through the diverter valve.

[0014] Optionally, when the first and second directional valves are in the through position, the hydraulic oil pumped by the load-sensitive pump acts on both ends of the displacement control valve through the first directional valve, and the pressures are equal. At this time, the large chamber of the second variable cylinder is connected to the return oil tank through the displacement control valve, and the first variable cylinder, under the action of the return spring in the spring chamber, will cause the load-sensitive pump to be in a large displacement state. Simultaneously, the hydraulic oil pumped by the load-sensitive pump will flow through the oil circuit to the bottom of the flow divider valve, and through the first directional valve to the spring chamber of the flow divider valve, where damping acts. When the pressure reaches the set value of the second pressure setting valve, a portion of the hydraulic oil will flow through the second pressure setting valve. The hydraulic oil flows to the return tank, where a pressure difference is generated across the damper. When the pressure difference exceeds the spring setting of the flow divider valve, the flow divider valve opens, and the hydraulic oil pumped by the load-sensitive pump flows to the return tank through the flow divider valve. At this time, the pressure at the outlet of the load-sensitive pump is always maintained as the sum of the spring settings of the second pressure setting valve and the flow divider valve. By adjusting the setting of the second pressure setting valve, the outlet pressure of the load-sensitive pump can be adjusted. After the hydraulic oil flows through the flow divider valve, a pressure loss occurs. The product of the pressure loss and the flow rate of the hydraulic oil is the hydraulic power. This power causes the temperature of the hydraulic oil to rise. The hydraulic power is adjusted by adjusting the setting of the second pressure setting valve, which in turn adjusts the rate of temperature rise of the hydraulic oil.

[0015] Optionally, the first and second directional valves are electrically controlled.

[0016] Optionally, the first and second directional valves are controlled by mechanical or hydraulic means.

[0017] Optionally, the pressures of the first pressure setting valve and the second pressure setting valve can be adjusted proportionally.

[0018] Optionally, the displacement control valve is also connected to the return oil tank.

[0019] Optionally, the hydraulic pump in the load-sensitive pump is connected to the vehicle engine.

[0020] Optionally, the piston rods of the first and second variable cylinders are respectively connected to both ends of the swashplate.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] This invention proposes a hydraulic oil preheating system and method suitable for load-sensitive systems. The hydraulic oil is circulated and heated by a hydraulic pump driven by an on-board engine. This can quickly increase the temperature of the hydraulic oil in low-temperature environments, enabling the hydraulic system to quickly reach its optimal operating state, thereby improving the reliability of hydraulic components and the safety of crane operation. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0024] Figure 1 This is a schematic diagram of the structure of a preheating system in the prior art;

[0025] Figure 2 This is a schematic diagram of the structure of a hydraulic oil preheating system according to an embodiment of the present invention;

[0026] Among them, 101-load sensitive pump, 101.1-first variable cylinder, 101.2-second variable cylinder, 101.3-hydraulic pump, 102-displacement control valve, 103-first pressure setting valve, 104-second pressure setting valve, 105-flow divider valve, 106-multi-way directional valve, 107-first directional valve, 108-second directional valve, 109-damping. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may include different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0029] In the description of this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0030] In the description of this invention, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0031] The application principle of the present invention will be described in detail below with reference to the accompanying drawings.

[0032] like Figure 2 As shown, this invention proposes a hydraulic oil preheating system suitable for load-sensitive systems, including a load-sensitive pump 101, a displacement control valve 102, a first pressure setting valve 103, a second pressure setting valve 104, a flow divider valve 105, a first directional valve 107, a second directional valve 108, a damper 109, and a multi-way directional valve 106; the load-sensitive pump 101 includes a hydraulic pump 101.3, a first variable cylinder 101.1, and a second variable cylinder 101.2;

[0033] The outlet of the hydraulic pump 101.3 is connected to the inlet of the first pressure setting valve 103, the flow divider valve 105, the first directional valve 107, the displacement control valve 102, and the multi-way directional valve 106, respectively. It is also connected to the control port of the displacement control valve 102 and the spring chamber of the first variable cylinder 101.1. The multi-way directional valve 106 is not controlled during the hydraulic oil preheating process by manual operation. The multi-way directional valve 106 will only participate in the operation when the vehicle is being driven.

[0034] The spring chamber of the displacement control valve 102 is connected to the oil outlet of the first reversing valve 107, the spring chamber of the diverter valve 105, and the oil inlet of the second reversing valve 108, respectively.

[0035] The large chamber of the second variable cylinder 101.2 is connected to the oil outlet of the displacement control valve 102;

[0036] The damper 109 is located between the oil inlet of the second directional valve 108 and the load feedback port of the multi-way directional valve 106.

[0037] The oil outlets of the first pressure setting valve 103, the second pressure setting valve 104, and the diverter valve 105 are all connected to the return oil tank.

[0038] In one specific embodiment of the present invention, the volume of the first variable cylinder 101.1 is greater than the volume of the second variable cylinder 101.2, that is, the first variable cylinder 101.1 is a large variable cylinder; the second variable cylinder 101.2 is a small variable cylinder.

[0039] In one specific embodiment of the present invention, when the first reversing valve 107 and the second reversing valve 108 are in the cut-off position, the hydraulic oil pumped by the load-sensitive pump 101 causes the displacement control valve 102 to switch through the control oil circuit, so that the cavities of the first variable cylinder 101.1 and the second variable cylinder 101.2 in the load-sensitive pump 101 are connected. Under the action of the area difference between the two variable cylinders (the first variable cylinder 101.1 and the second variable cylinder 101.2), the load-sensitive pump 101 is in a small displacement state. The hydraulic oil pumped by the load-sensitive pump 101, after meeting its own leakage requirements, will cause the hydraulic oil pressure at the outlet of the load-sensitive pump 101 to increase. When it reaches the set value of the diverter valve 105, it flows back to the oil tank through the diverter valve 105.

[0040] In one specific embodiment of the present invention, when the first reversing valve 107 and the second reversing valve 108 are in the through position, the hydraulic oil pumped by the load-sensitive pump 101 will act on both ends of the displacement control valve 102 through the first reversing valve 107, and the pressure acting is equal. At this time, the large chamber of the second variable cylinder 101.2 is connected to the return oil tank through the displacement control valve 102. At the same time, the first variable cylinder 101.1 will cause the load-sensitive pump 101 to be in a large displacement state under the action of the reset spring in the spring chamber. Meanwhile, the hydraulic oil pumped by the load-sensitive pump 101 will act on the bottom of the diverter valve 105 through the oil circuit, and the other path will flow through the first reversing valve 107 and the damper 109 to act on the spring chamber of the diverter valve 105. When the pressure reaches the set value of the second pressure setting valve 104, a portion of the hydraulic oil... The hydraulic oil flows to the return tank through the second pressure setting valve 104. At this time, a pressure difference is generated on the damper 109. When the pressure difference is greater than the spring setting value of the diverter valve 105, the diverter valve 105 will open, and the hydraulic oil pumped by the load-sensitive pump 101 will flow to the return tank through the diverter valve 105. At this time, the pressure value at the outlet of the load-sensitive pump 101 is always kept as the sum of the spring setting values ​​of the second pressure setting valve 104 and the diverter valve 105. By adjusting the setting value of the second pressure setting valve 104, the outlet pressure of the load-sensitive pump 101 can be adjusted. After the hydraulic oil flows through the diverter valve 105, a pressure loss is generated. The product of the pressure loss and the flow rate of the hydraulic oil is the hydraulic power. This part of the power causes the temperature of the hydraulic oil to rise. By adjusting the setting value of the second pressure setting valve 104, the hydraulic power is adjusted, and the temperature rise rate of the hydraulic oil is also adjusted.

[0041] As can be seen, the present invention can quickly switch between preheating mode and working mode through the first reversing valve 107 and the second reversing valve 108. In the working mode, the hydraulic system is initially in a low-pressure, small-displacement standby state, which does not affect the low-temperature start of the engine. After the engine starts, it switches to the preheating mode.

[0042] In one specific embodiment of the present invention, the first reversing valve 107 and the second reversing valve 108 are controlled by electronic means. In other specific embodiments of the present invention, the first reversing valve 107 and the second reversing valve 108 are controlled by mechanical means or hydraulic means. In practical applications, the control methods of the first reversing valve 107 and the second reversing valve 108 can be set according to actual needs.

[0043] In one specific embodiment of the present invention, the pressures of the first pressure setting valve 103 and the second pressure setting valve 104 can be adjusted proportionally. In a specific application, the overflow pressure is adjusted by the first pressure setting valve 103 and the second pressure setting valve 104, thereby controlling the heating rate of the hydraulic oil preheating system.

[0044] In one specific embodiment of the present invention, the displacement control valve 102 is also connected to the return oil tank.

[0045] In one specific embodiment of the present invention, the hydraulic pump in the load-sensitive pump 101 is connected to the vehicle engine. The present invention uses the vehicle engine as the power source, eliminating the need for an external power supply and making it convenient to use.

[0046] In one specific embodiment of the present invention, the piston rods of the first variable cylinder 101.1 and the second variable cylinder 101.2 are respectively connected to both ends of the swashplate. The first variable cylinder 101.1 and the second variable cylinder 101.2 drive the swashplate to rotate, thereby realizing the flow control of hydraulic oil at the outlet of the hydraulic pump.

[0047] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only used to facilitate the description of the present invention and to simplify the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of the present invention.

[0048] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A hydraulic oil preheating system suitable for load-sensitive systems, characterized in that: It includes a load-sensitive pump, a displacement control valve, a first pressure setting valve, a second pressure setting valve, a flow divider valve, a first directional valve, a second directional valve, a damper, and a multi-way directional valve; the load-sensitive pump includes a hydraulic pump, a first variable cylinder, and a second variable cylinder; The outlet of the hydraulic pump is connected to the inlet of the first pressure setting valve, the flow divider valve, the first directional valve, the displacement control valve, and the multi-way directional valve, respectively, and is also connected to the control port of the displacement control valve and the spring chamber of the first variable cylinder. The spring chamber of the displacement control valve is connected to the oil outlet of the first reversing valve, the spring chamber of the flow divider valve, and the oil inlet of the second reversing valve, respectively. The large chamber of the second variable cylinder is connected to the oil outlet of the displacement control valve; The damper is located between the oil inlet of the second directional valve and the load feedback port of the multi-way directional valve. The oil outlets of the first pressure setting valve, the second pressure setting valve, and the diverter valve are all connected to the return oil tank.

2. The hydraulic oil preheating system suitable for load-sensitive systems according to claim 1, characterized in that: The volume of the first variable cylinder is greater than the volume of the second variable cylinder.

3. A hydraulic oil preheating system suitable for load-sensitive systems according to claim 2, characterized in that: When the first and second directional valves are in the off position, the hydraulic oil pumped by the load-sensitive pump causes the displacement control valve to switch through the control oil circuit, making the chambers of the first and second variable cylinders in the load-sensitive pump connected. Under the effect of the area difference of the variable cylinders, the load-sensitive pump is in a small displacement state. The hydraulic oil pumped by the load-sensitive pump, after meeting its own leakage requirements, will cause the hydraulic oil pressure at the outlet of the load-sensitive pump to increase. When it reaches the set value of the diverter valve, it flows back to the oil tank through the diverter valve.

4. A hydraulic oil preheating system suitable for load-sensitive systems according to claim 2, characterized in that: When the first and second directional valves are in the through position, the hydraulic oil pumped by the load-sensitive pump acts on both ends of the displacement control valve through the first directional valve, and the pressures are equal. At this time, the large chamber of the second variable cylinder is connected to the return oil tank through the displacement control valve. Simultaneously, the first variable cylinder, under the action of the return spring in the spring chamber, will cause the load-sensitive pump to be in a large displacement state. At the same time, the hydraulic oil pumped by the load-sensitive pump will act on the bottom of the flow divider valve through the oil circuit, and the other path will flow through the first directional valve and through the spring chamber of the flow divider valve, where damping acts. When the pressure reaches the set value of the second pressure setting valve, a portion of the hydraulic oil will flow through the second pressure setting valve to... When the hydraulic oil returns to the oil tank, a pressure difference will be generated across the damper. When the pressure difference exceeds the spring setting value of the flow divider valve, the flow divider valve will open, and the hydraulic oil pumped by the load-sensitive pump will flow to the oil tank through the flow divider valve. At this time, the pressure value at the outlet of the load-sensitive pump is always maintained as the sum of the spring setting values ​​of the second pressure setting valve and the flow divider valve. By adjusting the setting value of the second pressure setting valve, the outlet pressure of the load-sensitive pump can be adjusted. After the hydraulic oil flows through the flow divider valve, a pressure loss is generated. The product of the pressure loss and the flow rate of the hydraulic oil is the hydraulic power. This power causes the temperature of the hydraulic oil to rise. The hydraulic power is adjusted by adjusting the setting value of the second pressure setting valve, and the rate of temperature rise of the hydraulic oil is also adjusted.

5. A hydraulic oil preheating system suitable for load-sensitive systems according to claim 1, characterized in that: The first and second directional valves are controlled by electronic control.

6. A hydraulic oil preheating system suitable for load-sensitive systems according to claim 1, characterized in that: The first and second directional valves are controlled by mechanical or hydraulic means.

7. A hydraulic oil preheating system suitable for load-sensitive systems according to claim 1, characterized in that: The pressures of the first pressure setting valve and the second pressure setting valve can be adjusted proportionally.

8. A hydraulic oil preheating system suitable for load-sensitive systems according to claim 1, characterized in that: The displacement control valve is also connected to the return oil tank.

9. A hydraulic oil preheating system suitable for load-sensitive systems according to claim 1, characterized in that: The hydraulic pump in the load-sensitive pump is connected to the vehicle engine.

10. A hydraulic oil preheating system suitable for load-sensitive systems according to claim 1, characterized in that: The piston rods of the first and second variable cylinders are respectively connected to both ends of the swashplate.

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