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EP0185894A1 - Installation hydraulique - Google Patents

Installation hydraulique Download PDF

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Publication number
EP0185894A1
EP0185894A1 EP85113850A EP85113850A EP0185894A1 EP 0185894 A1 EP0185894 A1 EP 0185894A1 EP 85113850 A EP85113850 A EP 85113850A EP 85113850 A EP85113850 A EP 85113850A EP 0185894 A1 EP0185894 A1 EP 0185894A1
Authority
EP
European Patent Office
Prior art keywords
oil
flow
hydraulic
cooler
flow resistance
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP85113850A
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German (de)
English (en)
Inventor
Franz Hübner
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of EP0185894A1 publication Critical patent/EP0185894A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B21/00—Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
    • F15B21/04—Special measures taken in connection with the properties of the fluid
    • F15B21/042—Controlling the temperature of the fluid
    • F15B21/0427—Heating
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B21/00—Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
    • F15B21/04—Special measures taken in connection with the properties of the fluid
    • F15B21/042—Controlling the temperature of the fluid
    • F15B21/0423—Cooling
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/80—Other types of control related to particular problems or conditions
    • F15B2211/85—Control during special operating conditions
    • F15B2211/851—Control during special operating conditions during starting

Definitions

  • the invention relates to a hydraulic system with a preferably small-volume oil tank, an oil feed pump fed from the oil tank, oil consumers supplied with pressure oil from the latter, a return line leading from these to an oil cooler connected on the outlet side to the oil tank, and with a control device which deepens the hydraulic oil when starting Bring temperatures to optimal operating conditions for as short a time as possible and keep these optimal operating conditions constant during operation within the narrowest possible limits.
  • the operating medium "hydraulic oil” has to fulfill several tasks.
  • the primary task is to transport the energy induced by the hydraulic pump in the form of pressure and deliver it to the consumer, where it is converted into mechanical work.
  • the second task is to move the moving parts of the system, i.e. H. to lubricate the sliding surfaces.
  • Another very important task is to absorb the losses that occur in the form of heat each time energy is converted into mechanical work and, in particular, to remove them from the heat-sensitive parts of the system, so that this heat is transferred to the environment, in particular ambient air, at a suitable point can be delivered.
  • Hydraulic oils have a temperature-disproportionate viscosity; at low temperatures the viscosity is very high, at high temperatures it is low and can drop so much that the important lubricating film on cohesive surfaces deepens its cohesion, thereby questioning the lubricating function. At particularly low temperatures, the viscosity can become so high that it causes a very high proportion of the losses in the hydraulic system due to the correspondingly high flow resistance
  • this system is also characterized by a high degree of efficiency, since no energy is required to drive a fan and the start-up phase, in which the system works with poor efficiency, is extremely short.
  • the invention is based on the already described prior art, the task of creating a hydraulic system of the type mentioned, in which the cooling is controlled without moving parts.
  • the hydraulic system mentioned at the outset is characterized according to the invention in that the control device is designed in the manner of a flow resistance balance, has a by-pass line which is flowed through in a rectilinear manner at least in the working area and has an abruptly narrowed flow cross-section, the length of which is negligibly small, with the return line and the oil tank, bridging the oil cooler, is directly or indirectly connected and the flow cross-section at the constriction point has a flow resistance adapted to the flow resistance of the oil cooler, and that the flow resistance of the oil cooler is at least half less than the flow resistance of the constriction point is when the hydraulic oil is in optimal operating condition.
  • the essential difference of the hydraulic system designed according to the invention compared to the described known designs is that although the oil temperature is kept constant by controlled cooling, and in a much better consistency than before, but as a metrological variable no longer, as before, the temperature of the oil , but its bisque is used.
  • the viscosity depends on the temperature of the oil and thus a certain temperature range defines optimal operating conditions of the oil, because then the viscosity is also within an optimal range, the detection and technical exploitation of the viscosity of the oil is a much more adapted procedure for the hydraulic system. After all, the way the pressure oil consumers work depends on the viscosity and the quality of the lubricating film is guaranteed by the viscosity of the oil and the efficiency of the system is greatest in an optimal viscosity range.
  • two flow resistances are thus connected in parallel between the return line and the oil container, the by-pass line with the constriction representing a constant resistance regardless of the respective viscosity of the hydraulic oil, but the oil cooler forms a resistance, the size of which high viscosity high, low viscosity low.
  • the two parallel flow paths each of which must be able to direct the oil flow from the return line to the oil tank alone, form a "flow resistance balance", which at one end provides the constant flow resistance, which is provided only by the pressure of the liquid and allows liquid quantities depending on the viscosity to flow through behind the constriction or orifice or the pressure difference, while at the other end of this balance the cooler forms a viscosity-dependent flow resistance, by means of which the flow rate increases in a viscosity-dependent manner in the sense of an inclination of the balance when the viscosity decreases, and reduced as the viscosity increases.
  • This cooling also starts immediately and continuously as soon as cooling is required.
  • this start of cooling can be done, if at all only approximately with very elaborately designed and expensive valves.
  • these valves open disproportionately from the closed position and allow more oil to pass through than would be required during the respective start phase or during the transition to the work phase with cooling, while the increase in oil flow through these valves is disproportionately small if stronger cooling is caused by higher cooling Oil temperatures are required
  • the invention offers over temperature-dependent valve-controlled cooling of hydraulic systems is that they start from extremely low temperatures. In such situations, the viscosity of the cold oil is hundreds of times greater than at operating temperature. If, after a certain start time, oil is to flow into the cooler by opening the control valve, the highly viscous oil in it forms a so-called oil plug, which temporarily prevents flow through the cooler. This can lead to disadvantages. According to the invention, however, the cooler is never completely separated from the oil circuit, but takes part in the oil circuit, even if with minimal proportions, so that the extremely cold, highly viscous oil in the cooler is gradually preheated during the general starting phase. Thus, with increasing cooling requirements after the start-up phase, there can also be a smooth transition of the oil flow through the cooler.
  • the hydraulic system designed according to the invention is equipped with an air convection cooler.
  • air convection cooling With air convection cooling, the cooling air flow and thus the heat emission or cooling of the oil in the oil cooler regulates itself depending on the heat supply of the oil.
  • the oil does not get into the hydraulic user undercooled and never reaches the hydraulic user as undercooled within the underlying cooling capacity.
  • favorable operating conditions of the oil are still achieved after a short start-up time, due to almost fluctuating oil viscosity (which is important for the economic operation of the hydraulic system) and also free of discontinuous, step-like changes.
  • the oil viscosity (depending on the oil temperature in the following) is the measured variable for controlling the oil cooling, because in the large working range of hydraulic oils and other oils in hydraulic systems from low to high oil temperatures the viscosity differences to the oil temperature difference steadily decrease from initially disproportionate to underproportional proportions , this ultimately means that larger oil temperature differences at high oil temperatures have smaller viscosity differences. Higher oil temperatures in turn improve the heat transfer to the cooling air.
  • the overall viscosity-dependent control behavior of the device is thus more sensitive and steadier than with temperature-dependent control.
  • the invention is used for hydraulic systems with fan cooling or water circulation cooling, it avoids the previously common pendulum phenomena of cooling in these systems, which occurred during the starting phase and under alternating loads.
  • the amount of the heated oil flowing to the cooler is regulated in each of these systems, but the heat output or the heat withdrawal from the oil is uncontrolled, in contrast to the air convection coolers. H. corresponds to the maximum power for which the cooler is designed.
  • oil with a significant low temperature leaves the cooler, which means that the temperature-dependent valves operate with less heating of the oil in the oil consumption and.
  • U. again close the oil flow to the radiator, etc., causing pumping or pendulum signs.
  • the result of the supercooling of the oil in the cooler being an increase in viscosity and thus an increase in the flow resistance of the cooler.
  • any temperature-dependent valve-controlled hydraulic system can be converted into a system that is controlled according to the invention according to viscosity.
  • the by-pass line is installed with the appropriate constriction.
  • the size of the constriction can either be determined graphically (with knowledge of the flow resistance of the cooler and its heat emission) or experimentally.
  • the invention provides, instead of the oil temperature-regulated control valve, which if necessary directs the entire oil flow or partial flow via the oil cooler into the container, an oil viscosity-independent, only oil flow quantity-dependent control aid (from the pressure difference before and after Control aids dependent) to be used, to split the line coming from the hydraulic user into two lines that are capable of absorbing the total oil flow, to lead a line to the oil cooling system in the oil cooler around which the coolant flows, and to lead a line further from the oil cooler to the tank , with the second line leading directly to the tank and providing an orifice or partial orifice as a control aid in this line to regulate the oil flows in the lines to the oil cooling system and directly to the tank via the orifice by structurally influenceable and selectable flow resistances in the oil cooling system and in the orifice .
  • an oil viscosity-independent, only oil flow quantity-dependent control aid from the pressure difference before and after Control aids dependent
  • This aperture can be connected in cooperation with the cooling system of the air-cooled oil convector driven by self-convection.
  • This diaphragm can also be provided in cooperation with a liquid-cooled oil cooler, the cooling system of which is provided in a container, the container being provided with inflow and outflow for the coolant, or the cooling system being in a free-flowing coolant flow.
  • the diaphragm is a disk with a sharp-edged central bore or a disk in the form of a circular section or other shaped circular section, the disk being fastened tightly at its edge in the line.
  • the flow rate Q " apart from the pressure before and after the orifice, is influenced slightly by the density kg / m 3 and not by the viscosity (kinematic viscosity My or cSt (qmm / s) of the oil is influenced by a flow factor alpha that can be structurally influenced, the depends on the cross section of the orifice F Bi to the cross section of the comprehensive tube F R
  • the flow factor alpha can be ascertained for specially designed orifices.
  • the flow resistance R in the tube or plate system is calculated using the known formula ⁇ p , where L is the flow length in the pipe or in the plate.
  • the incoming total oil flow (Qg es ) is divided into the two lines (with Q, to the oil cooling system, with Q, through the orifice to the tank), according to the relevant physical laws, the distribution of the oil flow quantities occurring in parallel lines depending on the flow resistances that occur .
  • the orifice with the relatively low flow resistance (R,) also acts in the extremely cold state as a safety device against excessive return pressure to the hydraulic user, which could occur as a result of high oil flow resistances in the oil cooling system.
  • the heating surface formed from the oil-flowing oil cooling system to the surrounding cooling medium is determined for the most unfavorable operating conditions; these are the minimum permissible oil viscosity and at the same time the maximum desired maximum value of the oil temperature and the largest possible ambient temperature of the cooling medium.
  • the heating surface cannot be changed during operation.
  • This device in the assignment of the oil cooling system, the oil tank, the orifice as control aid and to the user of the useful oil is thus able to quickly bring the oil from an extremely high oil viscosity range to an operationally favorable oil viscosity range.
  • the oil viscosity range is maintained, even at different ambient temperatures of the coolant and in a relatively small viscosity fluctuation range (the operation does not interfere or impair).
  • Fig. 1 the arrangement of the effective components of the device for needs-based controlled cooling of oils of a hydraulic device is shown schematically, in which the oil cooling system 5 consists of tubes or plates, which is located in a convectionally air-flowed oil cooler 13.
  • the advantage of choosing air as the cooling and heat-dissipating medium is that it can be used at ambient temperatures well below 0 degrees Celsius without further effort.
  • the oil From the hydraulic oil user 1, the oil first reaches the return line 2 and is divided into two lines 3 and 4 .
  • the line 3 conveys the oil via the air-cooled oil cooling system 5, via the subsequent line section 6 into the oil tank 7, which is advantageously equipped with a small capacity.
  • the by-pass line 4 conducts the oil via the orifice 8 as a regulating aid with the line 9 connected to it to the oil tank 7. From the oil tank 7, the oil is conveyed to the oil user 1 via the suction line 10 with the feed pump 11 and the feed line 1 2 .
  • the open arrows represent, for example, the ice-sifting air flow as a dissipating cooling medium.
  • the oil When starting up and shortly after starting up the hydraulic system from low ambient temperatures, the oil is drawn off from the oil tank 7 via the suction line 10 and through the feed pump 11 via the oil user 1, Via the return line 2 to the beginning of lines 3 and 4 promoted by the high flow resistance in the cold start-up state in the oil cooling system 5, which is a multiple of the flow resistance of the orifice 8, the largest part (up to 98%) of the total oil quantity through the Aperture 8 conveyed to the oil container 7. The small amount of residual oil is led through the oil cooling system 5 and the subsequent line section 6 to the oil tank 7. The initially low oil flow through the oil cooling system 5 is correspondingly cooled down. Both oil flows from lines 9 and 6 (or 3 and 4) mix to a mixing temperature , which is initially close to the oil temperature, from the uncooled line 9.
  • the oil is conducted in increasing amounts to the oil cooling system 5 of the oil cooler 13.
  • the oil mixing temperature in the oil container 7 is somewhat lower at a cold ambient temperature and thus the oil viscosity somewhat higher than at high ambient temperatures at which the oil mixing temperature is somewhat higher (and thus the oil viscosity slightly lower), but still in the operating range.
  • the oil viscosity of 38 cSt results for the frequently used oil HLP 4 6 at an ambient air temperature of minus 30 degrees Celsius and an oil mixing temperature of approximately 44 degrees Celsius; at an ambient air temperature of minus 35 degrees Celsius, the oil mixing temperature of approx.
  • oil viscosity for example, oil viscosities to the oil temperature 15000 cSt at minus 35 degrees Celsius, 550 cSt at 0 degrees Celsius, 130 cSt at plus 20 degrees Celsius , 70 cSt at plus 30 degrees Celsius oil temperature).
  • the resulting total pressure loss (R tot ) from the beginning of the lines 3 and 4 to the outlet of the lines 6 and 9 in the container 7 are in the entire oil temperature application area within the scope of known regulated oil cooling devices or else below, without additional services and expenses; because even known control devices are dependent on viscosity in the loss of flow pressure.
  • the Flow resistances of the cooling system and control device in known devices add up by connecting the flow resistances in series; decrease according to the present examples with the parallel connection of the flow resistances.
  • the oil cooling system 5 consisting of tubes, is provided in a water-circulating container 18, with cooling water inflow 19 and cooling water outflow 20, shown with the components and the control mode of operation of the oil flows as described in Fig. 1.
  • Appropriate devices must only be provided for heat dissipation with water, but these are also always required for hydraulic devices with liquid-cooled oil coolers.
  • Fig. 3 the oil cooling system 5, consisting of tubes or plates, is shown in a flowing liquid stream 14 which is guided by the socket 21, the device operating in the same manner as described above.
  • the auxiliary control element, the orifice 8 in an embodiment in which an active part, the orifice body 15, is screwed together as a flat and thin disk with its bore d Bi between two flanges 16 with the lines 9 and 4 connected to it is.
  • the inner diameter d R and the cross section of the pipes 4 and 9 as another active part directly influence the oil flow and oil resistance behavior, the oil viscosity-related oil flow Q, through the oil cooling system and the oil quantity-related oil flow Q. the container.
  • FIG. 5 shows the regulating auxiliary element, the diaphragm 8, in an embodiment in which the diaphragm body 15 is arranged in the sleeve 17 connecting the lines 4 and 9.
  • FIG. 6, 7 in longitudinal section in Fig.
  • Partial orifices are known to produce steadily increasing or decreasing flow losses even with low oil flow rates. It is advantageous if the partial diaphragm edge is vertical in the horizontal position of lines 4 and 9; this avoids that air or solid excretions can get stuck before or after the diaphragm body 15.
  • FIG. 8 shows the determined flow loss behavior of the orifice 8 (with R,), almost oil-viscosity and temperature-dependent, with R 1 , in an exemplary device.
  • On the abscissa are the oil quantity proportions of Q, and Q, of Qg es (0 - 100% and 1 00 - 0%) on the normal scale, on the ordinate the associated flow losses of the oil cooling system (R,) and orifice ( R,) plotted.
  • the total pressure loss Rg can be changed or adapted by the individual losses R, and R, and can be adapted to the desired or required oil viscosity behavior and oil cooling behavior of the device. It is therefore sufficient to replace the diaphragm body 15 according to FIGS. 4 to 7 with another diaphragm body 15 in order to correspond to changed oils and operating requirements.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fluid-Pressure Circuits (AREA)
EP85113850A 1984-12-20 1985-10-31 Installation hydraulique Withdrawn EP0185894A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3446453 1984-12-20
DE3446453A DE3446453C1 (de) 1984-12-20 1984-12-20 Hydraulikanlage mit einem vorzugsweise kleinvolumigen ölbehälter

Publications (1)

Publication Number Publication Date
EP0185894A1 true EP0185894A1 (fr) 1986-07-02

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Application Number Title Priority Date Filing Date
EP85113850A Withdrawn EP0185894A1 (fr) 1984-12-20 1985-10-31 Installation hydraulique

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EP (1) EP0185894A1 (fr)
DE (1) DE3446453C1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101858372A (zh) * 2010-03-30 2010-10-13 集美大学 油温控制装置
EP2305974A1 (fr) * 2009-09-24 2011-04-06 Eaton Truck Components Sp. z.o.o. Système de refroidissement de lubrification et procédé
CN108397315A (zh) * 2018-04-27 2018-08-14 江苏长川科技有限公司 一种用于油箱的水冷系统

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3803546A1 (de) * 1987-02-06 1988-08-18 Honda Motor Co Ltd Kuehlsystem zur wasserkuehlung von motoroel eines kraftfahrzeugs

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1860731A (en) * 1930-04-05 1932-05-31 Clarence H Cole Lubricating system
US2764147A (en) * 1951-02-23 1956-09-25 Northrop Aircraft Inc Frictional heater for hydraulic system
US3213930A (en) * 1964-06-01 1965-10-26 Robinson Robert Clayton Oil temperature regulators for internal combustion engines
GB1193718A (en) * 1966-09-13 1970-06-03 Abex Corp Temperature Responsive Hydraulic System and Valve Means Therefor
GB1350843A (en) * 1971-11-02 1974-04-24 Brown Tractors Ltd Hydraulic systems

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3751191A (en) * 1971-02-02 1973-08-07 Mott Corp Hydraulic pump and cooler unit

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1860731A (en) * 1930-04-05 1932-05-31 Clarence H Cole Lubricating system
US2764147A (en) * 1951-02-23 1956-09-25 Northrop Aircraft Inc Frictional heater for hydraulic system
US3213930A (en) * 1964-06-01 1965-10-26 Robinson Robert Clayton Oil temperature regulators for internal combustion engines
GB1193718A (en) * 1966-09-13 1970-06-03 Abex Corp Temperature Responsive Hydraulic System and Valve Means Therefor
GB1350843A (en) * 1971-11-02 1974-04-24 Brown Tractors Ltd Hydraulic systems

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2305974A1 (fr) * 2009-09-24 2011-04-06 Eaton Truck Components Sp. z.o.o. Système de refroidissement de lubrification et procédé
CN101858372A (zh) * 2010-03-30 2010-10-13 集美大学 油温控制装置
CN108397315A (zh) * 2018-04-27 2018-08-14 江苏长川科技有限公司 一种用于油箱的水冷系统

Also Published As

Publication number Publication date
DE3446453C1 (de) 1986-07-24

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