EP2354552A2 - Device for a pump and water pump - Google Patents

Abstract

The device has a pump wheel (2), and a switchable coupling arrangement for switchable connection of the pump wheel with a drive side. The pump wheel is rotatably supported on a rotatable drive shaft (1). An electromagnetic coil i.e. electromagnet (8), acts on a magnetically conductive anchor element (7). A contact unit e.g. engagement portion (6) and wedge element, is designed for force-fit and/or a form-fit connection with a contact portion (2a) at the pump wheel rotated on the drive shaft. The contact portion is brought at the wheel by a compression spring.

Description

State of the art

From the European patent application EP 2 105 624 is an electromagnetically actuated coupling for a water pump of the cooling water circuit of an internal combustion engine with a drive wheel is known, which can be rotatably mounted in the area or on the water pump and with an armature disc which cooperates with a coil. The coupling is constructed in such a way that a so-called "fail-safe" arrangement is provided in which a drive of a water pump via the coupling is possible even in the currentless state of the coil, for example if a failure of the electrical power supply takes place.

Purpose and advantages of the invention

The invention has for its object to provide a device for a pump, in particular water pump of a motor vehicle with clutch assembly, so that a switchable pump with a compact structure is created.

This object is solved by the features of claim 1 or 12.

In the dependent claims advantageous and expedient developments of the invention are given.

The invention is based on a device for a pump of a motor vehicle, in particular a water pump, for example for the cooling water circuit of an internal combustion engine. The pump includes a rotating impeller to be driven and a switchable clutch assembly for switchably connecting the impeller to a drive side. The core of the invention lies in the fact that the impeller is rotatably mounted on a rotatable drive shaft, so that a relative movement between impeller and drive shaft can take place. This allows the impeller to turn on the drive shaft. By this measure, it is possible to integrate a clutch assembly at least partially in a simple manner in a pump, in particular within a pump housing. The bearing of the impeller on the drive shaft can be done via roller bearings or plain bearings. Preferably, a cost-sliding bearing is used, since the operating time in which the impeller by a correspondingly switched clutch has a much lower speed than the drive shaft compared to the total service life is small. An eventual increased wear of a plain bearing compared to a rolling bearing is therefore manageable.

In an engaged state of the clutch, the impeller preferably has the speed of the drive shaft or an at least approximately rotational speed of the drive shaft. Ideally, however, there is no slippage between the drive shaft and impeller. In the disengaged state arises at least a relative speed between the impeller and a still rotating drive shaft. Preferably, the impeller is at a standstill or by prevailing friction forces in a state with a low towing speed.

To produce a disengaged and engaged state of the impeller is further proposed that the impeller is axially displaceable on the drive shaft. Thus, it is conceivable that a friction portion of the impeller cooperates by axial displacement with friction means, the rotatably mounted on the drive shaft are arranged.

In order to generate switching states of the coupling arrangement, it is also proposed that an electromagnetic coil is provided which acts in a current-fed state on a magnetically conducting armature element. Vorteilhafzersweise an anchor element is disposed within a pump housing. The electromagnetic coil can also be arranged within the pump housing for a compact and inexpensive construction. However, it is also conceivable to have an arrangement outside the pumper housing, which brings advantages with regard to electrical supply to the coil.

Furthermore, it is preferred if the armature element can be moved axially by an electromagnetic action of the coil, wherein the switching state of the impeller can be predetermined by an adjusting axial position of the armature element. As a result, for example, the impeller can be moved axially or the armature element moves a further element which acts on the impeller to produce a switching state.

To transmit a torque of the drive shaft to the impeller is proposed in a further preferred embodiment of the invention that non-rotatably on the drive shaft contact means, in particular friction means are arranged for a force and / or positive connection, in particular adhesion with a friction portion on the on Drive shaft rotatable impeller are designed.

In this context, it is also preferred if the anchor element and the friction means are matched to one another such that a frictional engagement between the drive shaft and impeller in response to an axial position of the anchor element is formed.

In a particularly preferred embodiment of the invention, a displacement member is provided, by means of which a contact portion, for. Example of a friction section of the Impeller can be brought into frictional contact with the friction means. Preferably, the displacement member, for example a spring, in particular a compression spring, in the axial direction on the impeller at a non-energized electromagnetic coil, so that a friction portion of the impeller is urged against friction means, which are rotatably connected to the drive shaft. In this way, a "fail safe" -Anordnung, which ensures a rotating impeller even if the power supply to the electromagnetic coil fails on a running internal combustion engine with rotating drive shaft. In particular, when using the pump in a cooling water circuit of an internal combustion engine, a high level of operational reliability can be ensured.

It is also advantageous if the anchor element arranged on a spring element which is non-rotatably connected to the drive shaft, wherein the spring element is adapted to exert on the impeller axial pressure effect, thus also in a non-energized state of the electromagnetic coil, at which no force effect on the anchor element occurs, allows a frictional engagement between a arranged on the spring element friction means and a corresponding friction portion on the impeller, so that a "fail-safe" arrangement is formed. By energizing the coil, for example, the armature element can be displaced axially in such a way that friction means which press resiliently against the impeller are lifted off from it, so that the pump impeller can rotate freely or substantially freely on the drive shaft.

In a further preferred embodiment, it is advantageous if the anchor element is arranged on the impeller. The anchor element may be mounted on the suction side or on the side facing away from the suction side of the impeller.

About a displacement member, in particular a spring element can not energized electric coil, the impeller in a clutched state are urged.

For a defined positioning of the impeller, it is further preferred if an axial bearing stop is formed on the drive shaft for the impeller. The bearing stop preferably has the functionality of a pivot bearing, so that in a case in which the pump impinges with axial compressive force on the bearing stop, and beyond, for example, no further frictional forces experienced by friction, even then can rotate freely.

In a preferred embodiment, the friction means on the drive shaft comprise a wedge member which is frictionally engageable with a friction portion of the impeller. In this way, the impeller can be brought to the rotational speed of the drive shaft with a comparatively low axial displacement force by a "wedge gear effect" of a wedge-shaped friction surface via frictional engagement.

The device according to the invention is preferably used for pumps in a motor vehicle, in particular water pumps. In internal combustion engines, the preferred application is the water pump for the cooling water circuit. A switchable cooling water pump allows the engine to reach operating temperature more quickly when it starts up from cold. For this purpose, the cooling water circuit is switched off by disengaging the impeller in this phase of engine operation. As soon as the engine is then at the specified operating temperature, the impeller is coupled, whereby the cooling water circuit is started.

figure description

Several embodiments of the invention are illustrated in the figures and will be explained in more detail below, indicating further advantages and details.

Figur 1

in schematischer Darstellung eine teilweise geschnittene Seitenansicht von Teilen einer Kühlwasserpumpe mit Kupplungsanordnung und

Figur 2 und 3

in einer entsprechenden Darstellung zwei weitere Ausführungsformen für vergleichbare Teile.

It shows:

FIG. 1

in a schematic representation of a partially sectioned side view of parts of a cooling water pump with clutch assembly and

FIGS. 2 and 3

in a corresponding representation, two further embodiments for comparable parts.

In FIG. 1 Elements of a cooling water pump with coupling arrangement are shown within a pump housing, not shown. The cooling water pump comprises a pump shaft 1, on which a pump wheel 2 is rotatably mounted via an axially and radially extending sliding bushing 3. The radial section 3a of the sliding bush 3 can abut against a radial bearing stop 4, for example in the form of a steel disc. In the bearing stop may also be integrated preferably a mechanical seal or a similar seal. The impeller 2 is as in FIG. 1 illustrated, preferably formed as an impeller, which is surrounded by a correspondingly shaped housing (not shown).

On the drive shaft rotatably mounted is a compression spring 5 with an engagement portion 6, which can cooperate positively and / or non-positively with the impeller 2. In the present case, a V-shaped or wedge-shaped groove 2a is annularly introduced into the impeller 2, in which the engagement portion 6 retracts to produce a frictional engagement between the correspondingly adapted engagement portion 6 and the groove 2a.

However, it is also conceivable that the engagement section 6 has form elements which fit into corresponding form elements in the V-shaped groove 2a, so that a positive connection is created in the engaged state.

On the engaging portion 6, a magnetically conductive anchor member 7, for example, a ring member is mounted, which cooperates with an electromagnet 8. The solenoid 8 may be mounted inside or outside the pump housing. In an arrangement outside the pump housing, a magnetic passage must be ensured by the pump housing to the anchor member 7 in order to exert a magnetic force on the anchor member 7 when the solenoid 8 is energized.

To limit the movement of the compression spring 5, on which the engagement portion 6 and the anchor member 7 are arranged, preferably stop elements, for example in the form of finger-shaped stop members are provided which axially restrict an axial movement of the anchor member 7 at a tightening force by the electromagnet 8.

The function of a water pump arrangement according to FIG. 1 Is as follows:

Due to the fact that in the non-energized state of the electromagnet 8, the engagement portion presses against the impeller 2, there is a "fail safe" arrangement in which in the de-energized state on the frictional action of the engagement portion 6, the impeller rotates at the same speed as the pump shaft 1.

To "decouple" the impeller, the electromagnet is subjected to a voltage which may be excessive in an initial period of time to pull the armature element against the electromagnet 8. Thus, the frictional engagement between the engaging portion 6 and the wedge-shaped groove 2 and the impeller is then freely rotatably supported on the pump shaft 1 releases. The axial stop fingers, not shown, in the region of the compression spring 5 limit the axial travel of the anchor element 7, so that this can not come to rest on the electromagnet 8 when the electromagnet is energized.

In Figure 2 an embodiment is shown in which the wedge-shaped groove 2a and the engagement portion 6 is replaced by a wedge member 9 which cooperates with a mating cone-shaped recess 10 on the impeller 2. A bearing stop 11, which is the radial portion 3 a of the bearing bush 3 opposite, is axially movable and is pressed by a compression spring in the axial direction against the impeller 2. Thus, the impeller 2 is displaced axially in the direction of the wedge member 9, whereby between the wedge member 9 and the conical recess 10 entstehz a frictional engagement. In this state, the impeller 2 preferably runs at the same speed as the pump shaft. 1

The frictional torque between impeller 2 and wedge element 9 drives the impeller 2. By energizing the electromagnet 8, the impeller 2 is pulled over an armature element 13 arranged in or on the impeller 2 in the direction of the electromagnet 8, thereby releasing the transmission of force between the wedge element 9 and the conical recess 10. The anchor element 13 may, for example, be cast into the impeller 2. The impeller is pressed against the bearing stop 11, for example in the form of a steel disc, which is designed so that no or substantially no drive torque is transmitted to the impeller when rotating the pump shaft 1. In this case, the impeller is disengaged. There is no pumping action.

In FIG. 3 an embodiment is shown, which is analogous to the embodiment of FIG. 2 operates, with the difference that the elements 8, 11, 12, 13 are transferred to the suction side, whereas the wedge member 9 and the matching cone-shaped recess 10 on the side facing away from the suction side 14 15 are arranged.

According as in the embodiment according to FIG. 2 is pressed in the de-energized state of the electromagnet 8 by the compression spring 12, the impeller 2 against the wedge member 9, whereby the drive torque of the pump shaft 1 is transferable to the impeller 2 by frictional engagement. By energizing the electromagnet 8, the impeller 2 can be disengaged, in the pump wheel 2 is pulled away from the wedge element 9 via the anchor element 13 by means of an axial movement of the pump wheel 2 on the pump shaft 1. This represents the disengaged state.

LIST OF REFERENCE NUMBERS

1

pump shaft

2

impeller

2a

groove

3

bearing bush

3a

radial section

4

bearing stop

5

compression spring

6

Engriffsabschnitt

7

anchor member

8th

electromagnet

9

key member

10

cone-shaped recess

11

bearing stop

12

compression spring

13

anchor member

14

suction

15

opposite side

Claims (12)

Device for a pump of a motor vehicle, in particular water pump with a rotating impeller to be driven (2) and a switchable coupling arrangement for switchably connecting the impeller (2) with a drive side, characterized in that the impeller (2) on a rotatable drive shaft (1) rotatable is stored. Apparatus according to claim 1, characterized in that the impeller (2) on the drive shaft (1) is arranged axially displaceable. Device according to one of the preceding claims, characterized in that an electromagnetic coil (8) is provided, which acts in an energized state on a magnetically conductive anchor member (7, 13). Device according to one of the preceding claims, characterized in that the armature element (7, 13) by a magnetic action of the coil (8) is axially movable, wherein by an adjusting axial position of the armature element (7, 13) of the switching state of the impeller ( 2) can be specified. Device according to one of the preceding claims, characterized in that rotationally fixed to the drive shaft (1) Kcntaktmittel (6, 9) are arranged, which for a force and / or positive connection with a contact portion (2a, 10) rotatable on the on the drive shaft Impeller are designed. Device according to one of the preceding claims, characterized in that the anchor element (7, 13) and the contact means (6, 9) are matched to one another such that a force and / or positive connection between the drive shaft and pump impeller in dependence on an axial position of the Anchor element (7, 13) can be predetermined. Device according to one of the preceding claims, characterized in that a displacement member (12) is provided, by means of which a contact portion (10) on the impeller in form and / or frictional engagement with the contact means (9) can be brought. Device according to one of the preceding claims, characterized in that the anchor element (7) on a spring element (5) is arranged, which is non-rotatably connected to the drive shaft (1) in communication, wherein the spring element (5) is adapted to the impeller to press axially. Device according to one of the preceding claims, characterized in that the anchor element (13) is arranged on the impeller. Device according to one of the preceding claims, characterized in that on the drive shaft (1) for the impeller an axially acting bearing stop (4, 11) is formed. Device according to one of the preceding claims, characterized in that the contact means on the drive shaft (1) comprise a friction means in the form of a wedge element (9) which can be brought into frictional engagement with a friction section (10) of the impeller (2). Pump for a motor vehicle, in particular a water pump with a device according to one of the preceding claims.

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