Coolant pump for motor vehicle, with adjustable drive

The present invention relates to a controllable drive for a motor vehicle, especially for a water pump in a motor vehicle.

Variable-speed drives for a motor vehicle are known and are used, for example, to control the water pump speed to the flow of The cooling medium for an internal combustion engine as a function of dissipated to regulate heat energy. The couplings used in the prior art have, inter alia, the problem that a reliable speed setting problematic because of the difficult torque transmission is or the control range is relatively small, in particular also an economically sensible use in a motor vehicle, in particular for an internal combustion engine to enable.

In the prior art drives are also known, whose output speed controlled as a function of the degree of filling of a coupling with shear fluid is, where among other things, with decreasing amount of oil, the threat of uncontrolled Standstill of the drive is. This results, for example when driving a water pump in a motor vehicle to that of the internal combustion engine Generated heat is not adequately dissipated and motor overheating threatening.

Similar disadvantages also have so-called hysteresis, however, additionally comprise regulatory problems in small torque ranges, so that here too there is a risk that an uncontrolled standstill the drive of the coupling occurs.

Object of the present invention is thus, a controllable drive provide for a motor vehicle, which the known in the art avoids disadvantages or at least reduced, and as a result of improved speed control of the driven unit, such as a water pump, the operation of an internal combustion engine improved.

The inventive controllable drive for a motor vehicle, in particular for a water pump in a motor vehicle, has a rotatably mounted Shaft, on which at least one rotatably mounted output body and at least arranged a rotatably mounted drive body. In between the driving body and the driven body is a coupling region arranged, which can accommodate a viscous fluid. The controllable drive is characterized in that at least one first and at least a second flow path are provided, which space a fluid reservoir connect to the coupling region between the drive and driven body. The controllable drive is further characterized in that one, with at least one actuator in position variable means is provided which at least one passage opening of at least one changed flow path of the drive.

When driving body according to the present invention, at least partially understood profiled discs that rotate or rotatably on a Shaft are supported, and in particular for transmitting a predetermined be used torque.

As output body are also at least partially profiled discs understood that cooperate with at least one drive body in such a way that directly or indirectly a predetermined torque of is transmitted to the driving body to the driven body.

The term flow path according to the present invention for portions the variable drive used at least partly from a viscous fluid to flow through.

According to a particularly preferred embodiment, the drive for a coolant pump, in particular a clutch portion which substantially by interlocking, concentric profile structures at least is formed either side of the drive and driven body. Through this coupling the field of drive and driven bodies are to Transmission particularly a predetermined torque coupled.

The drive for a coolant pump, according to a further particularly preferred embodiment, at least one controllable device on, in particular, with a magnetic field electromagnetically that, for example, by a induced magnetic field of the actuator is controlled. The actuator for this purpose has at least one, in particular a plurality of magnet coils , which by means of a control line with a control device are connected. ferromagnetic In combination with further preferably Components of the drive according to the invention, a predetermined Magnetic controlled built inside the drive.

According to a further particularly preferred embodiment of a drive for a coolant pump, the electromagnetically controllable devices Valves, especially poppet valves, which according to a particularly preferred embodiment, comprise at least one restoring device.

The electromagnetically controlled device, according to a further particularly preferred embodiment, at least one axially movable Anchor on to which a magnetic force, in particular the induced by the actuator electromagnetic force acts.

According to another particularly preferred embodiment, the A drive for a coolant pump, in particular two controllable devices on which, for example, contradictory or counter a flow path open and close another flow path.

It is also within the scope of the present invention, a controllable device provide that opens multiple flow paths of the drive or closes. It is also within the scope of the present invention, that the controllable means to take a plurality of intermediate positions, can to the volume flow of the viscous fluid in dependence to control at least one predetermined parameter or to regulate.

According to another particularly preferred embodiment, the actuator or are part of the actuator outside the rotating Clutch, or the drive is arranged. The control of the Fluid level in the coupling area between the driving and driven body According to a further particularly preferred embodiment, by a time-variable aperture ratio of controllable devices causes concerning the flow paths.

Further, according to a particularly preferred embodiment, in the rest position the controllable device of the flow path in the coupling areas open to the fluid and the flow path for the fluid closed from the clutch area out.

As the rest position according to the present invention, in particular the State referred to in which no magnetic field from the electromagnetic actuator is induced.

This rest position is, according to another particularly preferred embodiment, caused by a restoring device, further in accordance with a particularly preferred embodiment, a restoring spring which is configured for example as a double annular plate spring.

Such a return spring may cause a restoring force in that it from a rest position by applying, for example, an electromagnetic Force is changed in such a way that the thereby caused Change in position, the return spring constrained to the waste during Magnetic field, the controlled device, such as the tilt valve, returns to its rest position.

It is also within the scope of the present invention instead of a double annular Return spring, to use other spring means, which in accordance with a further particularly preferred embodiment, in the rest position of the controllable device a predetermined restoring force on the controllable device maintains.

The restoring force, according to another particularly preferred embodiment, aligned so that it by the actuator in particular its Coil acts directed away.

According to another particularly preferred embodiment, the A drive for a coolant pump at least one further flow path on, which has no controllable device, with which the passage opening the flow path is changed.

According to a further particularly preferred embodiment, the Controlling the electromagnetic means in particular of the hereto arranged armature by a pulse width modulated signal with which The control of the actuator.

In particular, an improved control of the electromagnetically provide controllable device, according to a further particularly preferred embodiment, on the shaft of the drive and / or the shaft of the coolant pump is mounted a pulse generator is provided for determining the speed.

The mounting of the actuator is performed in accordance with a further particularly preferred Embodiment in the area over the bearing of the coolant pump.

According to another particularly preferred embodiment, the A drive for a coolant pump, a locking device for, with which in particular the drive and driven body form-fitting and / or can be positively connected. This device is used in particular to in a possible failure of the drive torque transmission to provide between the drive and the driven body.

The present invention further includes an apparatus for operating a cooling system for a motor vehicle, comprising at least one Coolant pump, a drive unit and at least one drive according to any one of the preceding claims.

The purpose of the present invention also includes the use of a Drive according to at least one of the preceding claims for operating a cooling system for a motor vehicle.

The invention is described with reference to various embodiments described in detail. It should be noted, however, that by illustrated herein embodiments of the scope of the present invention should not be restricted, but rather is shown by way of example, what opportunities the invention to design a drive for a includes motor.<dl tsize="6"><dt>Fig. 1</dt><dd>a sectional view of the drive according to the invention for a water pump in a first shift position;</dd><dt>FIG. 2</dt><dd>a sectional view of the drive according to the invention for a water pump in a second shift position;</dd><dt>Fig. 3</dt><dd>shows a further alternative embodiment of the invention drive; </dd><dt>Fig. 4</dt><dd>a further alternative embodiment of the invention Drive with a locking device;</dd><dt>Fig. 5</dt><dd>schematic representation of an alternative embodiment the drive according to the invention;</dd><dt>Fig. 6</dt><dd>a resetting device for a drive according to the invention;</dd><dt>Fig. 7</dt><dd>a functional diagram for the valve control of an inventive Drive.</dd></dl>

According to the illustrated in Fig. 1 according to the invention for driving a Water pump has an integrated these Flüssigkeitsreibkupplung on that is divided into two areas, for example. The first area is called so-called coupling portion 14 defined by the space in which the housing of the drive as a drive body 2 and with the water pump shaft associated driven element 12 for transmitting a torque can be coupled together. This coupling area particularly preferably by a plurality of narrow, maze-like column formed between the drive pulley and the driven pulley, whereby the Torque transmission by a predetermined amount of viscous fluid is determined in the coupling area. The second area is a pantry 13, in the soft unneeded for torque transmission viscous Fluid is kept or stored.

Between these two areas, which at approximately the same diameter can be within the drive enclosure, for example a Partition wall 34 is arranged with a plurality of, preferably two valves 4, 5, the volume flow of the viscous fluid in at least one direction control or regulate.

Fig. 1 shows both the return valve 4, as well as the inlet valve 5 can be seen, which the flow path between the areas described above open or close. The drive according to the illustrated here Embodiment further includes a pump shaft 6, a pump impeller 8 and a pump housing 10. Further, Figure 1. The controllable device 3, which via an actuator, wherein at least one magnet coil 11 has is driven.

The torque of the drive according to the invention is according to the here illustrated embodiment, via a pulley 9 and a herewith transmitted associated drive assembly to the drive according to the invention and the rotationally fixed connection in the coupling region of the Drive launched.

In open feed valve 5, as shown in Fig. 1, fills the Coupling region with viscous fluid and transmits the introduced from the outside Torque on the driven pulley 12. This is rotatably connected to the connected to the pump shaft 6, so that the pump impeller 8 is set in rotation becomes. If the bearing of the pulley 9 and the housing cover via the bearing 17, which according to the embodiment in Figure 1 is arranged offset to the pump shaft bearings 25th

The control of the relevant for the torque transmission levels of the viscous fluid in the coupling area 14 is achieved in that the Aperture ratio of the two valves 4 and 5 is variable over time. The Actuation of the valves is effected by at least one actuator preferably arranged outside the rotary Flüssigkeitsreibkupplung and having particular stationary anchored solenoids 11th

The magnetic field generated when current flows through the coil is ferromagnetic Components of the clutch housing into the housing interior of the invention led drive and acts axially on a mobile Anchor 3 of electromagnetically controllable device. The anchor itself actuated for example by its axial movement on locally attached Tongues or lever, the valves 4 and 5 of the drive, and thereby cause a filling or emptying of the clutch area 14th

According to a particularly preferred embodiment of the present Invention, the valves in relation to the induced by the armature 3 Adjusting movement so arranged that in each case a valve is opened and the other closed is.

To further ensure the reliability of a vehicle is in a preferred embodiment of the present invention, the arrangement selected the valves so that the inlet valve opens 5 and the return valve 4 is closed. Here is the axially movable armature 3 in a spaced apart at rest position of the actuator to the Actuator of the drive according to the invention.

This position is in particular also effected in that a return spring 16 is provided, which in addition to centering the example annular or segment-shaped armature 3, this well-energized the magnetic coils 11 in a, in relation to the magnet coil remote position urges. In this position, due to the centrifugal force maximum promoted the viscous fluid in the coupling area, so that the driven pulley and thus driven water pump with the preset speed becomes.

Between the coil 11 and the armature 3 are further in accordance with that shown in Fig. 1 Illustrated embodiment, magnetically non-conductive components or Assemblies 35 interposed to the magnetic flux in the drive on a to conduct predetermined path.

For permanent energization of the solenoid 11 (see FIG. FIG. 2), the anchor tightened due to the forces acting on it and magnetic force against the Restoring force of the return spring in an opposite end position in relation drawn to the rest position. In this position, according to the illustrated here Embodiment, the feed valve 5 is closed, so that no viscous Fluid can flow into the coupling portion 14th On the other side However, by the arrangement and connection of the valves, the return valve 4 opened in this position, which means one in Flüssigkeitsreibkupplungen common Abpumpeinrichtungen the viscous fluid from the coupling portion 14 is pumped into the storage area 13 of the drive becomes.

As regards the function and design of such a vacuum pump system and the basic function of a Flüssigkeitsreibkupplung is on DE 102 38 739.7 referred to the object by reference present invention.

To maintain a minimum speed of the water pump in accordance with a Embodiment of the drive according to the invention a not shown or more working gaps, ie radially oriented flow paths outside disposed of the vacuum pump system, so that the coupling region is not completely emptied, and because of the fate of a given Amount of viscous fluid in the coupling area a predetermined minimum torque get to drive the water pump remains.

Fig. 2 shows the embodiment according to the invention a controllable drive is shown in FIG. 1 in the energized state of the magnet coil 11. In this case one hand, the intake valve 5 is closed and the return valve 4 open.

To the required adjustment of the predetermined water pump speed to reach and steuem, when control is a vote of Switching characteristic of the valves and the interaction of the Öffriungsverhältnisse the valves significantly. This results in the function of the speed control between a predetermined minimum and a predetermined maximum driving speed according to the invention characterized in that the armature of the means controllable by a pulse width modulated signal to the Solenoid coils or the magnet coil of the actuator is clocked and thereby is moved toward and forth. The pulse width modulated signal determined Thus, the duty cycle of the armature movement and thereby the temporal Aperture ratio of the two valves.

In FIG. 7, the opening characteristics of the valves 4 and 5 is illustrated with a graph.

Depending on the energization of the actuator 3 of the armature moves a rest position into a parking position. This armature movement arises in the representation of FIG. 7 by the reference number 40, which links the position the armature in the rest position when energized actuator (s = 0) and is indicated right when supply actuator (s = 1).

Lines 4 and 5 indicate the setting position of the valves 4 and 5 between a open position to a closed position 1 0 to. Thus, the inlet valve 4 opened in de-energized state of the actuator and is in energized state closed. The opposite applies for the position of Return valve. 5

According to a particularly preferred embodiment of the invention Drive is the geometry of the valves and the vacuum pump system so designed so that, for example, a duty cycle of 60% energization and 40% Nichtbestromung the solenoid 11 at a clock frequency of z. B. 1 Hertz causes a reduction of the driving speed by 40%.

To improve the control quality and control quality of invention Drive, this drive further includes a speed sensor exhibit. For this purpose, as shown in FIG. 4, a pulse generator 22 at the be attached pump shaft or one of its affiliated member whose Signal is picked up by a speed sensor 23 and to a control device can be transferred. Conveniently, the sensor connected to the solenoid coil 11 to the particular advantage of to use common electrical connections.

In the embodiment of Figs. 1 and 2, the clutch housing is supported bearings, preferably roller bearings, which are directly on the pump housing are arranged. This inter alia results in an advantage that the Pump shaft 6 with the driven pulley 12 and the pump impeller 8 itself largely free from supporting forces are, for example, to the pulley Act. This allows the storage correspondingly lighter be executed or easier.

Fig. 3 shows an alternative embodiment of the drive according to the invention, wherein the bearing for the pump impeller 18 and the pulley or the housing cover 18 are arranged one over the other, whereby the length of the drive according to the invention are reduced can.

However, stacked on the two bearings is already well characterized achieved that at least a predetermined region of the bearing above the other is arranged.

In the alternative embodiment, as shown in Fig. 4, the inventive controllable drive as a separate unit at a water pump arranged. Advantageously, in such a case, the shaft the water pump for the storage of the inventive drive used.

According to the embodiment shown in Fig. 4, the inventive Driving means having a blocking device, with which after a failure of Flüssigkeitsreibkupplung between the driven clutch housing and driving body and the driven pulley a particularly force-locking connection is made. For this purpose, the front cover has a closable opening 20 , into which an insert 21 can be used, which form and / or Adhesion to the pump shaft on the drive body and produces output body.

In FIG. 5, a further embodiment of the drive according to the invention illustrated in which the actuator on the front side, ie the front side of the drive, is arranged. The mounting of the actuator 30 via the Bearing 19, which is supported on the rotating coupling member.

Fig. Figure 6 shows a return spring for the drive according to the invention, which the controllable device preferably pushes into its rest position. in this connection the restoring spring may be made in one piece and is made according to the in Fig. 6 illustrated embodiment, essentially comprises two concentric Rings 32, 33 by a plurality of individual arms and / or sipes are connected. These resilient blades are substantially uniformly distributed over a predetermined radius of the rings and flat in a Angle aligned to the tangent to the inner ring 33 of the return spring. They also preferably do not extend over a constant Radius, but have a curved shape, which is given a Radius portion r₁ - r₂ the rings extend.