Hydraulic oil preheating system suitable for load-sensitive system

Abstract

The invention discloses a hydraulic oil preheating system suitable for a load sensitive system. The hydraulic oil preheating system comprises a hydraulic pump, a first variable cylinder, a second variable cylinder, a displacement control valve, a first pressure setting valve, a second pressure setting valve, a diverter valve, a first reversing valve, a second reversing valve, a damper and a multi-way reversing valve. An oil outlet of the hydraulic pump is connected with oil inlets of the first pressure setting valve, the flow divider valve, the first reversing valve, the displacement control valve and the multi-way reversing valve, and is also connected with a control port of the displacement control valve and a spring cavity of the first variable cylinder; a spring cavity of the displacement control valve is connected with an oil outlet of the first reversing valve, a spring cavity of the diverter valve and an oil inlet of the second reversing valve; a large cavity of the second variable cylinder is connected with an oil outlet of the displacement control valve; the damper is arranged between an oil inlet of the second reversing valve and a load feedback port of the multi-way reversing valve; and oil outlets of the first pressure setting valve, the second pressure setting valve and the diverter valve are connected with an oil return tank. The temperature of hydraulic oil can be increased in a low-temperature environment, so that a hydraulic system reaches an optimal operation state.

Description

Technical Field

[0001] The invention belongs to the technical field of engineering machinery, and in particular relates to a hydraulic oil preheating system suitable for a load sensing system. Background Art

[0002] Cranes working in extremely cold environments need to preheat the hydraulic system. If the appropriate temperature is not reached, the sealing effect of the seals will be affected, reducing their lifespan, and even causing damage and oil leakage. The conventional hydraulic system preheating process is: after the engine is started, the crane is in standby mode, and the hydraulic oil passes through the main pump to the diverter valve in the main valve and then returns to the oil tank. During this process, the hydraulic oil generates heat through the main valve interception to heat the system, thereby achieving the preheating effect. In this process, for load-sensitive systems, the pump only outputs hydraulic oil that meets its own leakage volume in the standby state. If it is throttled by the main valve, the hydraulic system will take a long time to preheat. If the hydraulic oil preheating time is short, it will induce the failure of the sealing elements in the valve, destroying its sealing effect, resulting in later damage and oil leakage, reducing reliability, and increasing maintenance costs.

[0003] The Chinese utility model patent with publication number CN217518999U discloses a preheating system and engineering machinery, such as Figure 1 As shown, it includes: a hydraulic oil tank with a cavity; a temperature sensor, which is arranged in the hydraulic oil tank; a pump body, which is connected to the hydraulic oil tank; a preheating device, which is arranged in the hydraulic oil tank; a controller, which is 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 the controller 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 supply. One is to use a vehicle battery. When it is used for a long time to heat the hydraulic oil, the battery capacity will be reduced. Long-term use will cause the battery to lose power and cannot meet the huge current required when the engine is started, thereby affecting the engine start. At the same time, it is limited by the capacity of the vehicle battery, and the heating component cannot be used on a large scale to preheat other systems; the other method uses an external power supply, which is greatly affected by the working environment. Summary of the invention

[0004] In view of the above problems, the present invention proposes a hydraulic oil preheating system suitable for a load-sensitive system. The hydraulic pump is driven by a vehicle-mounted engine to realize circulating heating of the hydraulic oil. The hydraulic oil temperature can be quickly increased in a low-temperature environment, so that the hydraulic system can quickly reach the optimal operating state, thereby improving the reliability of hydraulic components and the safety of crane operations.

[0005] In order to achieve the above technical objectives and the above technical effects, the present invention is implemented through the following technical solutions: A hydraulic oil preheating system suitable for a load-sensitive system, comprising a load-sensitive pump, a displacement control valve, a first pressure setting valve, a second pressure setting valve, a diverter valve, a first reversing valve, a second reversing valve, a damper and a multi-way reversing valve; the load-sensitive pump comprises a hydraulic pump, a first variable cylinder and a second variable cylinder; The oil outlet of the hydraulic pump is respectively connected to the oil inlets of the first pressure setting valve, the diverter valve, the first reversing valve, the displacement control valve and the multi-way reversing 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 respectively connected to the oil outlet of the first reversing valve, the spring chamber of the diverter valve and the oil inlet of the second reversing valve; The large chamber of the second variable cylinder is connected to the oil outlet of the displacement control valve; The damper is arranged between the oil inlet of the second reversing valve and the load feedback port of the multi-way reversing valve; The oil outlets of the first pressure setting valve, the second pressure setting valve and the diverter valve are all connected back to the oil tank.

[0006] Optionally, the volume of the first variable cylinder is greater than the volume of the second variable cylinder.

[0007] Optionally, when the first reversing valve and the second reversing valve are in the cut-off position, the hydraulic oil pumped out by the load-sensitive pump causes the displacement control valve to be reversed through the control oil circuit, so that the cavities of the first variable cylinder and the second variable cylinder in the load-sensitive pump are connected. Due to the area difference of the variable cylinders, the load-sensitive pump is in a small displacement state. When the hydraulic oil pumped out by the load-sensitive pump meets the leakage of itself, the excess hydraulic oil will increase the hydraulic oil pressure at the outlet of the load-sensitive pump, and when the setting value of the diverter valve is reached, it will flow back to the oil tank through the diverter valve.

[0008] Optionally, when the first reversing valve and the second reversing valve are in the through position, the hydraulic oil pumped out by the load-sensitive pump will act on both ends of the displacement control valve through the first reversing valve, and the acting 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 at the same time, the first variable cylinder will put the load-sensitive pump in a large displacement state under the action of the return spring in the spring chamber; at the same time, the hydraulic oil pumped out by the load-sensitive pump will act on the bottom of the diverter valve through the oil circuit in one way, and flow through the damping through the first reversing valve to act on the spring chamber of the diverter valve in the other way. When the pressure reaches the set value of the second pressure setting valve, a part of the hydraulic oil will flow through the second pressure setting valve Flows to the return oil tank, at which time a pressure difference is generated on the damping. When the pressure difference value is greater than the spring setting value of the diverter valve, the diverter valve will be opened, and the hydraulic oil pumped out by the load-sensitive pump will flow to the return oil tank through the diverter valve. At this time, the pressure value at the outlet of the load-sensitive pump is always maintained at the sum of the setting values ​​of the second pressure setting valve and the diverter valve spring. By adjusting the setting value of the second pressure setting valve, the load-sensitive pump outlet pressure is adjusted. After the hydraulic oil flows through the diverter valve, 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 increases the temperature of the hydraulic oil. The hydraulic power is adjusted by adjusting the setting value of the second pressure setting valve, and the temperature rise rate of the hydraulic oil is adjusted at the same time.

[0009] Optionally, the first reversing valve and the second reversing valve are electrically controlled.

[0010] Optionally, the first reversing valve and the second reversing valve are mechanically controlled or hydraulically controlled.

[0011] Optionally, the pressures of the first pressure setting valve and the second pressure setting valve are proportionally adjustable.

[0012] Optionally, the displacement control valve is also connected to the oil return tank.

[0013] Optionally, the hydraulic pump in the load sensing pump is connected to an onboard engine.

[0014] Optionally, the piston rods of the first variable cylinder and the second variable cylinder are respectively connected to two ends of the swash plate.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention proposes a hydraulic oil preheating system and method suitable for a load-sensitive system. The hydraulic pump is driven by a vehicle-mounted engine to realize cyclic heating of the hydraulic oil. The hydraulic oil temperature can be quickly increased in a low-temperature environment, so that the hydraulic system can quickly reach an optimal operating state, thereby improving the reliability of hydraulic components and the safety of crane operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative labor, among which: Figure 1 It is a structural schematic diagram of a preheating system in the prior art; Figure 2 A schematic diagram of the structure of a hydraulic oil preheating system according to an embodiment of the present invention; 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-diverter valve, 106-multi-way reversing valve, 107-first reversing valve, 108-second reversing valve, 109-damping. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to those of ordinary skill in the relevant field may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may also include different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so that once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0019] In the description of the present invention, "several" means more than one, "many" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0020] In the description of the present invention, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" 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 representation of the above terms does 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.

[0021] The application principle of the present invention is described in detail below in conjunction with the accompanying drawings.

[0022] like Figure 2 As shown, the present invention proposes a hydraulic oil preheating system suitable for a load-sensitive system, comprising a load-sensitive pump 101, a displacement control valve 102, a first pressure setting valve 103, a second pressure setting valve 104, a diverter valve 105, a first reversing valve 107, a second reversing valve 108, a damper 109 and a multi-way reversing valve 106; the load-sensitive pump 101 comprises a hydraulic pump 101.3, a first variable cylinder 101.1 and a second variable cylinder 101.2; The oil outlet of the hydraulic pump 101.3 is respectively connected to the oil inlets of the first pressure setting valve 103, the diverter valve 105, the first reversing valve 107, the displacement control valve 102 and the multi-way reversing valve 106, and 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 reversing valve 106 is manually controlled, and during the hydraulic oil preheating process, the multi-way reversing valve 106 does not participate in the control, and only when the vehicle is operated, the multi-way reversing valve 106 will participate in the work; 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; The large chamber of the second variable cylinder 101.2 is connected to the oil outlet of the displacement control valve 102; The damper 109 is provided between the oil inlet of the second reversing valve 108 and the load feedback port of the multi-way reversing valve 106; The oil outlets of the first pressure setting valve 103 , the second pressure setting valve 104 and the diverter valve 105 are all connected back to the oil tank.

[0023] In a specific implementation of the embodiment of the present invention, the volume of the cavity of the first variable cylinder 101.1 is greater than the volume of the cavity 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.

[0024] In a specific implementation of the 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 out by the load-sensitive pump 101 causes the displacement control valve 102 to be reversed 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 communicated, and the load-sensitive pump 101 is in a small displacement state due to the area difference between the two variable cylinders (the first variable cylinder 101.1 and the second variable cylinder 101.2). When the hydraulic oil pumped out by the load-sensitive pump 101 meets the leakage of itself, the excess hydraulic oil will increase the hydraulic oil pressure at the outlet of the load-sensitive pump 101, and when it reaches the set value of the diverter valve 105, it will flow back to the oil tank through the diverter valve 105.

[0025] In a specific implementation of the 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 out 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 acting pressures are 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, and 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 return spring in the spring chamber; at the same time, the hydraulic oil pumped out by the load-sensitive pump 101 will act on the bottom of the diverter valve 105 through the oil circuit in one way, and the other way will flow through the first reversing valve 107 through the damping 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, part of the hydraulic oil It will flow to the return oil tank through the second pressure setting valve 104, and a pressure difference will be generated on the damping 109 at this time. When the pressure difference value is greater than the spring setting value of the diverter valve 105, the diverter valve 105 will be opened, and the hydraulic oil pumped out by the load-sensitive pump 101 will flow to the return oil tank through the diverter valve 105. At this time, the pressure value at the outlet of the load-sensitive pump 101 is always maintained as the sum of the second pressure setting valve 104 and the spring setting value of 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 increases the temperature of the hydraulic oil. The hydraulic power is adjusted by adjusting the setting value of the second pressure setting valve 104, and the temperature rise rate of the hydraulic oil is adjusted at the same time.

[0026] It can be seen that the present invention can quickly switch between the preheating mode and the operating mode through the first reversing valve 107 and the second reversing valve 108. In the operating mode, the initial state of the hydraulic system is low-pressure and small-displacement standby, which does not affect the low-temperature starting of the engine. After the engine is started, it switches to the preheating mode.

[0027] In a specific implementation of the embodiment of the present invention, the first reversing valve 107 and the second reversing valve 108 are electrically controlled. In other specific implementations of the embodiment of the present invention, the first reversing valve 107 and the second reversing valve 108 are mechanically controlled or hydraulically controlled. In actual application, the control mode of the first reversing valve 107 and the second reversing valve 108 can be set according to actual needs.

[0028] In a specific implementation of an embodiment of the present invention, the pressures of the first pressure setting valve 103 and the second pressure setting valve 104 can be proportionally adjusted. In a specific application process, the overflow pressure is adjusted by the first pressure setting valve 103 and the second pressure setting valve 104 to control the heating speed of the hydraulic oil preheating system.

[0029] In a specific implementation of the embodiment of the present invention, the displacement control valve 102 is also connected to the oil return tank.

[0030] In a specific implementation of the embodiment of the present invention, the hydraulic pump in the load-sensing pump 101 is connected to the vehicle engine. In the present invention, the vehicle engine is used as the power source, and no external power supply is required, which is convenient to use.

[0031] In a specific implementation of an 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 the two ends of the swash plate, and the first variable cylinder 101.1 and the second variable cylinder 101.2 drive the swash plate to rotate, thereby realizing flow control of the hydraulic oil at the oil outlet of the hydraulic pump.

[0032] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the protection content of the present invention.

[0033] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

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

2. A hydraulic oil preheating system suitable for a load sensing system 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 a load sensing system according to claim 2, characterized in that: When the first reversing valve and the second reversing valve are in the cut-off position, the hydraulic oil pumped out by the load-sensitive pump causes the displacement control valve to be reversed through the control oil circuit, so that the cavities of the first variable cylinder and the second variable cylinder in the load-sensitive pump are communicated. Under the effect of the area difference of the variable cylinders, the load-sensitive pump is in a small displacement state. When the hydraulic oil pumped out by the load-sensitive pump meets the leakage of itself, the excess hydraulic oil will increase the hydraulic oil pressure at the outlet of the load-sensitive pump. When the hydraulic oil reaches the set value of the diverter valve, it will flow back to the oil tank through the diverter valve.

4. A hydraulic oil preheating system suitable for a load sensing system according to claim 2, characterized in that: When the first reversing valve and the second reversing valve are in the through position, the hydraulic oil pumped out by the load-sensitive pump will act on both ends of the displacement control valve through the first reversing valve, and the acting 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 at the same time, the first variable cylinder will put the load-sensitive pump in a large displacement state under the action of the return spring in the spring chamber; at the same time, the hydraulic oil pumped out by the load-sensitive pump will act on the bottom of the diverter valve through the oil circuit in one way, and flow through the damping through the first reversing valve to act on the spring chamber of the diverter valve in the other way. When the pressure reaches the set value of the second pressure setting valve, a part of the hydraulic oil will flow to the second pressure setting valve through the second pressure setting valve. Return to the oil tank, at this time, a pressure difference will be generated on the damping. When the pressure difference value is greater than the spring setting value of the diverter valve, the diverter valve will be opened, and the hydraulic oil pumped out by the load-sensitive pump will flow to the return oil tank through the diverter valve. At this time, the pressure value at the outlet of the load-sensitive pump is always maintained as the sum of the setting values ​​of the second pressure setting valve and the diverter valve spring. By adjusting the setting value of the second pressure setting valve, the load-sensitive pump outlet pressure is adjusted. After the hydraulic oil flows through the diverter valve, 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 increases the temperature of the hydraulic oil. The hydraulic power is adjusted by adjusting the setting value of the second pressure setting valve, and the temperature rise rate of the hydraulic oil is adjusted at the same time.

5. The hydraulic oil preheating system suitable for a load sensing system according to claim 1, characterized in that: The first reversing valve and the second reversing valve are electrically controlled.

6. The hydraulic oil preheating system suitable for a load sensing system according to claim 1, characterized in that: The first reversing valve and the second reversing valve are controlled mechanically or hydraulically.

7. The hydraulic oil preheating system suitable for a load sensing system 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. The hydraulic oil preheating system suitable for a load sensing system according to claim 1, characterized in that: The displacement control valve is also connected to the oil return tank.

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

10. The hydraulic oil preheating system suitable for a load sensing system according to claim 1, characterized in that: The piston rods of the first variable cylinder and the second variable cylinder are connected to two ends of the swash plate respectively.

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