WO1985002227A1

WO1985002227A1 - Temperature regulated fan drive for high power drives

Info

Publication number: WO1985002227A1
Application number: PCT/EP1984/000354
Authority: WO
Inventors: Siegfried Winkelmann; Rudolf Schneider
Original assignee: Zahnradfabrik Friedrichshafen Ag
Priority date: 1983-11-17
Filing date: 1984-11-08
Publication date: 1985-05-23
Also published as: DE3440428A1

Abstract

Temperature regulated fan drive for high power engines, particularly internal combustion engines, wherein the rotation speed of the cooling fan is changed as a function of the dissipation of heat generated by the engine. To this effect, there is provided before the cooling fan a differential planetary gear to which is adjoined an adjustable operation sliding brake. The latter may be a hydraulic pump for the cooling water of the engine, an electric hysteresis brake or an electric generator. The resulting sliding power may be used at another location or may be annihilated.

Description

Temperature controlled fan drive for high performance machines

The invention relates to a temperature-controlled fan drive for high-performance machines. to which a temperature sensor, influenced by the coolant temperature of the machine, for controlling a coupling device between the machine and the cooling fan is assigned.

In the case of cooling fans on machines, in particular on internal combustion engines that are used in construction machines, the high design power required for these cooling fans is only required temporarily. The coolant temperature is a measure of the fan power actually required. In the case of a predetermined drive speed of the machine, which is usually too high for the cooling fan, by changing the slip of a slip clutch, the cooling fan can be operated with the

Operating speed that corresponds to the fan power currently required. There are a variety of devices that allow the fan speed to be adapted to the needs. From DE-PS 1 176 427 a fluid coupling with slip that can be changed as a function of the temperature is known, in which the distance between the coupling halves can be adjusted by means of a temperature-responsive element. In the slip area of this clutch, heat loss occurs in it, which is undesirable per se at this point. The design of the cooling system on high-performance machines is selected so that the full mo-

can be used in the long term. This results in a relatively large fan output, which is approximately 5% of the nominal motor output. It is understandable that controllable fan drives are particularly widespread here. Other known couplings between a drive machine and a fan, such as eg viscous couplings or fluid couplings, cannot be used in compact machines because of their considerable size.

The invention has for its object to provide a temperature-controlled fan drive for high-performance machines, which can be made smaller and more compact, generates less heat loss and works more wear-free and can be controlled in a simpler manner than was previously possible with known solutions.

According to the invention the object is achieved by the features listed in the characterizing part of claim 1.

The invention has the advantages over the known that the fan drive can be constructed compactly and with a small size. By using a fixed component as part of the slip brake, compared to known solutions in which e.g. both coupling halves rotate, the setting of the torque and thus the speed considerably easier. The slip brake only requires a smaller torque in relation to the gear ratio than a clutch directly in the drive train of the cooling fan. The fan drive can run in continuous operation and is still wear-free. The slip brake can be used for ventilation and / or cooling

T * fcO C «& * ^• serving turbo blower. However, it can also be a pump that supports the cooling medium circulation of the machine, or can supply energy as a hydraulic pump, compressor or electrical generator to any location, for example to a hydraulic accumulator, a pneumatic accumulator or an electrical accumulator, from where the energy can then be called up if necessary.

Further advantageous embodiments of the invention are evident from the following description, the claims and the drawing.

The invention is explained using exemplary embodiments with reference to the drawing. Show it

1 shows a section through a fan drive according to the invention with a pump as a braking element for the differential epicyclic gear,

2 shows another exemplary embodiment of a fan drive according to the invention with a pump, in the inlet of which there is an expansion element which actuates a throttle valve located in its outlet,

3 shows a circuit diagram with the pump and the throttle valve lying in series with it,

4 shows a diagram showing the course of the powers, speeds and torques of the device, 5 shows another embodiment of a fan drive according to the invention similar to that of FIG. 2, but the throttle valve is arranged parallel to the centrifugal pump,

6 shows a circuit diagram with the pump and the throttle valve according to FIG. 5 lying parallel to it,

Fig. 7 shows another embodiment of the invention with an electrical hysteresis brake.

A cooling fan 1 (FIG. 1) is to be driven by a machine (not shown in the drawing) via a drive belt 3 running on a belt pulley 16. A differential epicyclic gear 2 serves to transmit the torque required for this purpose. An integral part of the shaft 6 is a sun gear 5 of the di ferential epicyclic gear 2, the web of which is embodied by the pulley 16. Planetary wheels 20 of the differential epicyclic gear 2 are rotatably mounted on bearing bolts 21, which in turn are mounted in the pulley 16. The shaft 6 and thus the sun gear 5 are operatively connected to a brake for the differential epicyclic gear 2. In the exemplary embodiment, this brake is formed by a pump 7, which is located in a housing 9. The shaft 6 is rotatably connected to the rotor of the pump 7. This lies in a fluid circuit which preferably carries cooling water from the machine. The cooling water is supplied to the pump 7 via an inlet connector 10, and the outlet via an outlet connector 11. The flow resistance in the line circuit connected to the inlet connection 10 and the outlet connection 11 (not shown in FIG. 1) can be varied depending on the cooling water temperature in such a way that it also increases as the temperature of the cooling water of the machine increases ¬ increases and decreases with falling temperature. This is achieved by a thermostatic valve which is known per se and is connected to the line circuit. The increasing flow resistance of the conduit circuit, which also includes the pump 7, increases with increasing cooling water temperature, which has an increased braking effect which the pump 7 exerts on the differential epicyclic gear 2. The variable torque on the sun gear 5, through the translation in the differential epicyclic gear 2, produces a corresponding torque on the ring gear 4 and thus on the cooling fan 1, as a result of which the latter rotates at the corresponding speed. In this operating state, the sun wheel 5 and thus also the rotor of the pump 7 rotate at the speed resulting from the speed difference and transmission ratio. If the cooling water temperature of the machine becomes lower, the flow resistance in the line circuit becomes smaller by opening the throttle valve 15 and thus the braking effect which the pump 7 exerts on the differential epicyclic gear 2.

In another exemplary embodiment (FIG. 2), a pump 7 is also used as the brake, in this case a centrifugal pump which is equipped with an inlet opening 12 and an outlet opening 13. An expansion element 14, which is flushed with the incoming cooling water, is also installed in its housing 9 and controls a throttle valve 15 as a function of the temperature profile of the cooling water of the machine. For this purpose, the throttle valve 15 is in the drain line of the cooling water. The cooling water, coming from the drain opening 13 in the housing 9 of the pump 7, passes the throttle valve 15 and leaves the housing 9 via the drain connector 11. The corresponding current flow results from FIG. 3, from which the series connection of the inlet connector 10, Pump 7, throttle valve 15 and outlet 11 also emerges. If the temperature of the cooling water of the machine rises, the throttle valve 15 increases the flow resistance in the fluid circuit, in which the pump 7 is also included, by closing. This is due to an increased braking effect which the pump 7 exerts on the differential epicyclic gear 2. The variable torque on the sun gear 5, due to the translation in the differential epicyclic gear 2, produces a corresponding torque on the ring gear 4 and thus on the cooling fan 1, as a result of which the latter rotates at the corresponding speed. In this operating state, the sun gear 5 and thus also the rotor of the pump 7 rotate at the speed resulting from the speed difference and the gear ratio. If the cooling water temperature of the machine falls, the flow resistance in the line circuit decreases by opening the throttle valve 15 and thus the braking effect which the pump 7 exerts on the differential epicyclic gear 2.

In a further embodiment (FIG. 5), which is similar to that of FIG. 2, a bypass channel 22 has additionally been provided in the housing 9 of the pump 7, which bypass valve 15 is more or less released depending on the temperature of the cooling water . A throttle point 19 is installed in the housing 9 of the pump 7 between the outlet opening 13 of the pump 7 and the outlet nozzle 11. At low temperature of the cooling water of the machine, the expansion element 14 causes the throttle valve 15 to open, as a result of which pressure build-up in the outlet opening 13 and thus a high speed of the cooling fan 1 are prevented. When the temperature of the cooling water of the machine increases, the throttle valve 15 closes, as a result of which a pressure builds up in the outlet opening 13. A correspondingly occurring braking action in the pump 7 influences the differential epicyclic gear 2 in such a way that the cooling fan 1 runs faster.

The circuit of pump 7, throttle valve 15 arranged in parallel thereto and throttle point 19 connected in series with the parallel connection is also shown in the circuit diagram in FIG. 6.

In another exemplary embodiment (FIG. 7), the brake for the differential epicyclic gear 2 is constructed as a hysteresis brake 8 known per se, in the housing 9 of which radially pronounced and mutually offset poles 23, 24 and a shaft 6 with the shaft 6 are rotationally fixed connected rotor 25 are provided, via a connecting line 17, a winding 18 is charged with high strength current at high temperature of the cooling water of the machine and with lower current at low temperature of the cooling water. The control of the current intensity according to the temperature of the cooling water of the machine can be done by an NTC resistor, by a snap switch or another suitable device, e.g. B. an electronic circuit, to which a thermal sensor is assigned, can be effected as a function of the cooling water temperature.

With increasing temperature of the cooling water of the machine, the current through the winding 18 increases, which has an effect through an increased braking effect, via the rotor 25 and

Shaft 6 arrives from the hysteresis brake 8

Braking torque to the differential epicyclic gear 2. There is a corresponding torque on the ring gear 4 and thus on

Cooling fan 1 effective, causing this with the corresponding

Speed turns. The sun gear 5 and thus the rotor 25 rotate in this operating state with the speed resulting from the speed difference and gear ratio. If the temperature of the cooling water of the machine drops, then the current flow through the winding 18 is reduced via a corresponding sensor element, possibly in conjunction with an electronic circuit, the braking effect of the hysteresis brake 8 becomes smaller, and the cooling fan 1 runs more slowly.

The course of the powers, speeds and torques of the exemplary embodiment according to FIG. 7 are illustrated on the basis of a diagram (FIG. 4), where P is the drive power, P _{g is} the slip power on the sun gear, M_ the torque on the sun gear, M_ the torque of the cooling fan, P_ the power consumption of the cooling fan, n _g the speed at the sun gear and n_ 1_ mean the speed of the cooling fan.

The mounting of the cooling fan 1 and the rotor of the slip brake on the same shaft 6 (FIGS. 1, 2, 5, 7), which also forms the sun gear 5, contributes to the desired, particularly compact structure of the fan drive. The cooling fan 1 could also be stored separately.

^' 3-

reference numeral

1 cooling fan

2 differential planetary gears

3 drive belts

4 ring gear

5 sun gear

6 wave

7 pump

8 hysteresis brake

9 housing

10 inlet connection

11 drain connector

12 Inlet opening

13 drain opening

14 expansion element

15 throttle valve

16 pulley

17 connecting line

18 winding

19 throttling point

20 planet gear

21 bearing bolts

22 bypass channel

23 pin

24 pin

25 rotor

Claims

Temperature-controlled fan drive for high-performance machines

1. Temperature-controlled fan drive for high-performance machines, to which a temperature sensor influenced by the coolant temperature of the machine for controlling a coupling device between the machine and the cooling fan is assigned, characterized in that the cooling fan (1) of the machine has a dif ¬ differential epicyclic gear (2) is connected upstream, one part (web) of which is connected to the drive (pulley 16) of the machine, the other part (ring gear 4) of which is connected to the cooling fan (1) in a rotationally fixed manner, and the third part ( Sun wheel 5) is in operative connection with an adjustable slip brake (pump 7; hysteresis brake 8).

2. Fan drive according to claim 1, characterized in that a fluidic pump (7) is provided as a slip brake.

3. Fan drive according to one of claims 1 and 2, characterized in that the pump (7) serves as a feed pump for the cooling medium of the machine.

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4. Fan drive according to one of claims 1 to 3, characterized in that the pump (7) comprises means (expansion element 14, throttle valve 15) for changing the flow resistance for the cooling medium as a function of its temperature.

5. Fan drive according to claim 1, characterized in that a hysteresis brake (8) is provided as a slip brake (Fig. 7).

6. Fan drive according to claim 5, characterized g e k e n n z e i c h n e t that the hysteresis brake (8) at higher cooling water temperature of the machine with current of high current, at low cooling water temperature with a lower current is applied.

7. Fan drive according to claim 5, characterized in that the current for the hysteresis brake (8) is controlled by a temperature-dependent actuator acted upon by the cooling water.

8. Fan drive according to claim 7, characterized in that the cooling fan (1) is mounted on the shaft (6).

9- fan drive according to one of the preceding claims, characterized in that an electrical generator serves as a slip brake.