WO2011095559A1

WO2011095559A1 - Drive device for an auxiliary unit

Info

Publication number: WO2011095559A1
Application number: PCT/EP2011/051592
Authority: WO
Inventors: Philipp Ebner; Alexander Fuerschuss
Original assignee: Magna Powertrain Ag & Co Kg
Priority date: 2010-02-04
Filing date: 2011-02-03
Publication date: 2011-08-11
Also published as: DE112011100447A5

Abstract

A drive device for an auxiliary unit of a motor comprises a shaft and a pulley, which are used as the input element and output element, respectively, and a shiftable gear unit for adjusting the rotational speed, the gear unit being disposed between the shaft and the pulley. The gear unit comprises a first gear ratio step having a first toothing region and a second toothing region which meshes with the first toothing region, and a second gear ratio step disposed in series relative to the first gear ratio step and having a third toothing region and a fourth toothing region which meshes with the third toothing region. The second and third toothing regions are designed on a single common gear element of the gear unit.

Description

Drive device for an accessory

The present invention relates to a drive device for an accessory of an engine, in particular in a motor vehicle, with a shaft and a pulley, which serve as input element and output element, and with a switchable speed-matching gear unit, which is effective between the shaft and the pulley,

Such a device can be used to transmit a torque from an internal combustion engine to one or more ancillary components of the internal combustion engine, such as a generator, a power steering pump, an air conditioning compressor and / or a water pump. Insofar, it may be in the shaft of the drive device may be the crankshaft of the internal combustion engine, or the shaft of the drive device may be drivingly coupled to the crankshaft of the internal combustion engine. Alternatively or in addition to the mentioned internal combustion engine, the shaft of the drive device can be coupled to an electric motor, which serves as the drive source of the vehicle. The transmission of torque to an accessory via the pulley and a V-ribbed belt, which drives a corresponding input pulley of the accessory. The shiftable transmission unit makes it possible to switch between a first and a second transmission ratio back and forth. By changing from the smaller gear ratio to the larger gear ratio, the speed of the accessory can be increased if necessary. This makes it possible to make better use of the power of the auxiliary unit, for example at low engine speeds a translation into fast and at high engine speed a translation-free drive from the crankshaft to the accessory is selected. In this way, a correspondingly smaller accessory can be used to meet the performance requirements. By using smaller ancillaries, costs can be saved and fuel consumption reduced.

A drive device of the type mentioned is described for example in the published patent application DE 196 21 642 AI. The disclosed there drive device is mounted directly on an end face of the motor housing.

Alternatively, it is also possible to attach the drive device to an accessory of an internal combustion engine, wherein said shaft is formed in this case by the drive shaft of the accessory or is drivingly connected thereto. In this configuration, torque is not transmitted from the shaft to the pulley, but inversely from the pulley to the shaft. Accordingly, the pulley forms the input element and the shaft forms the output element. For a speed increase of the auxiliary unit relative to the crankshaft of the internal combustion engine in this case, the translation from the shaft to the pulley must be slow. Such a device is known from the published patent application DE 38 10 91 1 AI.

In this context, it should be noted that in certain applications, even in the range of low engine speeds, a translation into slow between combustion engine and auxiliary unit can be provided, which is switched to direct drive at high engine speeds. Likewise, instead of the direct drive through In addition, an arbitrary, in relation to the further transmission ratio depending on the configuration serial or slower gear ratio be provided. For the sake of simplicity, only the case in which the torque transmission from the shaft to the pulley takes place and in which a changeover to fast and a direct through drive is switched over is expressly considered below. However, the invention is not limited to this particular application. There is a need to make drive devices for ancillaries with a switchable gear unit space-saving and to expand the range of achievable ratios.

This object is achieved by a drive device with the features of claim 1.

According to the invention, the gear unit comprises a first gear stage having a first gear portion and a second gear portion meshing with the first gear portion and a second gear stage arranged in series with the first gear stage having a third gear portion and a fourth gear portion meshing with the third gear portion. The second and the third toothed region are formed on a single transmission element of the transmission unit, which is referred to below as "common transmission element" of the two gear ratios.

Due to the two-stage design of the transmission unit, a higher transmission ratio can be achieved overall than with a single-stage transmission. At the same time, however, the required installation space is not considerably increased, since two of the existing toothed areas are formed on a single component of the transmission unit. The speed of the accessory can thus be increased by a substantial amount at low engine speed, whereby the use of a smaller accessory is possible. This saves both weight and cost and allows fuel savings.

The common transmission element may be an intermediate gear having an inner toothing and an outer toothing cooperating with the first toothed region and the fourth toothed region. In particular, the intermediate gear may be annular. The external toothing of such an annular intermediate gear can then form the second toothed region and the internal toothing can form the third toothed region. In the case of a gear reduction, the internal toothing of the intermediate gear can also form the second toothed region and the external toothing can form the third toothed region. Such an intermediate gear, which has both an internal toothing and an external toothing and thus is effective for both translation stages, allows the saving of weight and space.

According to one embodiment of the invention, the first gear portion is formed on an input gear of the gear unit and the fourth gear portion is formed on an output gear of the gear unit. For example, the input gear may be couplable to the shaft while the output gear is drivingly coupled to the pulley. Alternatively, the input gear may be coupled to the pulley while the output gear is drivingly coupled to the shaft. At the Gangszahnrad and the output gear can be in particular spur gears with straight, oblique or helical toothing.

The drive device can be designed in such a way that the shaft can be selectively coupled to the input gear or to the output gear in order to drive it. For this purpose, two suitable coupling devices, such as e.g. Friction clutches, freewheels or brakes, be provided. With a coupling of the shaft {as the input element) with the input gear of the gear unit, a translation takes place, preferably in rapid, corresponding to the two transmission stages arranged in series. In a direct coupling of the shaft (as the entrance element) with the output gear, for example, a direct drive, bypassing the gear ratios, corresponding to a ratio of 1: 1, be established. The input gear and the intermediate gear are carried along freely in this case. The coupling devices allow switching between two gear ratios.

According to one embodiment of the invention, a freewheel is provided between the shaft and the pulley. The freewheel can be one

Provide rotational sense and / or speed difference dependent coupling of shaft and output gear. In a translation into the fast, the output gear is faster than the shaft, the freewheel opens. However, as soon as the input gear from the shaft (as input element) is decoupled and is therefore no longer driven, its speed decreases so long until the output gear has reached the speed of the shaft. Upon reaching this state locks the freewheel and there is a direct drive from the shaft to the pulley. The freewheel can, depending on the application, also in various other places be arranged between the shaft and the gear unit or between the pulley and the gear unit.

According to a further embodiment, a controllable clutch, in particular an electromagnetically actuated friction disk clutch, is provided between the shaft and the belt pulley. The coupling may in particular be arranged between the shaft and the gear unit or between the belt pulley and the gear unit. Alternatively, the clutch may also be integrated in the transmission unit. The controllable clutch makes it possible to selectively couple the input element or the output element of the transmission unit with a member of the transmission unit. For example, the clutch can be used to couple the crankshaft with a ring gear of the transmission unit.

According to one embodiment of the invention, the input gear and the output gear comprise an internally toothed ring gear and an externally toothed sun gear coaxial with the ring gear, wherein an internal toothing of the common transmission element (in particular of the already mentioned intermediate gear) meshes with the sun gear and meshes the external toothing of the common transmission element with the ring gear , For example, therefore, the ring gear can form the input gear and the sun gear can form the output gear. Due to the nested arrangement of the three gears, so by the formed from outside to inside sequence ring gear - common transmission element - sun, a particularly space-saving design of a two-stage transmission gear is possible.

The common transmission element may be arranged eccentrically, in particular with respect to the ring gear and the sun gear. Through the ex- centric arrangement of the common transmission element, different numbers of teeth between the internal teeth of the result

Ring gear and the external teeth of the common gear member on the one hand and the internal teeth of the common gear member and the outer toothing of the sun gear on the other hand, whereby a translation can be realized between the ring gear and sun gear.

Preferably, the common transmission element is rotatably mounted about a fixed axis. The common transmission element thus does not rotate planetary, but rotates off-axis to the input gear and the output gear. The common transmission element can be mounted for this purpose by means of a rolling bearing and / or by means of a sliding bearing in a housing of the transmission unit. The aforementioned sun gear and the ring gear is in particular coaxial with the shaft, so for example, the crankshaft arranged. As a result, a particularly compact housing of the drive device is achieved on the motor housing. According to a preferred embodiment, the gear unit is completely integrated in the pulley. This type of accommodation is made possible in particular by the small extent of the gear unit in the axial direction.

It may further be provided a fixedly coupled to the shaft vibration damper, which is arranged axially spaced from the pulley. The crankshaft, for example, led out through a respective central bore of the sun gear and pulley from the gear unit and rotatably connected to a separate, arranged next to the pulley vibration damper. The vibration damper may be integrated in a housing of the transmission unit. Alternatively, it may be arranged outside a housing of the gear unit.

Further embodiments of the invention are described in the dependent claims, the description and the accompanying drawings.

The invention will now be described by way of example with reference to the drawings.

Fig. 1 shows a side sectional view of an inventive

Drive device according to a first embodiment.

Fig. 2 shows a simplified front view of a transmission unit of

Drive device according to FIG. 1.

Fig. 3 shows a side sectional view of an inventive

Drive device according to a second embodiment.

According to FIG. 1, a drive device 10 is fastened to an internal combustion engine 1 1 of a motor vehicle, which is only partially shown. The drive device 10 serves to transmit a torque output by the internal combustion engine 1 1 to a belt pulley 14 via which an unillustrated V-ribbed belt for driving an auxiliary unit of the internal combustion engine 1 1, for example a power steering pump or an air-conditioning compressor, runs. In order to adjust the speed of the pulley 14 and thus the driven input shaft of the auxiliary unit to different operating conditions of the internal combustion engine 1 1, the drive device 10 comprises a switchable gear unit 16, which between the crankshaft 12 of the internal combustion engine 1 1 and the pulley 14 is arranged. The gear unit 16 is accommodated in a housing 17 and comprises three toothed elements, namely a ring gear 18 with an internal toothing 20, a sun gear 22 arranged inside the ring gear 18 and coaxial thereto with external toothing 24 and between the ring gear 18 and the sun gear 22 arranged intermediate gear 26, which is annular. The intermediate gear 26 comprises both an outer toothing 28 and an outer toothing 28 coaxial inner toothing 30 and thus forms a single common transmission element of the gear unit 16. The sun gear 22 and the ring gear 18 are rotatably mounted on the crankshaft 12 by means of suitable rolling bearings. The sun gear 22 is also drivingly connected to the pulley 14. As is apparent from the front view of Fig. 2, the intermediate gear 26 with respect to the ring gear 18 and the sun gear 22 is arranged eccentrically and mounted so that it is rotatable about a parallel to the crankshaft axis A extending, fixed Zwischenzahnradachse B. In order to avoid a flying bearing of the intermediate gear 26, eccentrically arranged bearings 31 and a bearing ring 38 are provided, which are fixedly connected to the housing 17, wherein the connection extends partially through the two free spaces, which between the ring gear 18 and the intermediate gear 26 and between the intermediate gear 26 and the sun gear 22 are formed.

The distance between the crankshaft axis A and the intermediate gear axis B is selected such that the internal teeth 20 of the ring gear 18 meshes with the external teeth 28 of the intermediate gear 26 and the internal teeth 30 of the intermediate gear 26 meshes with the external teeth 24 of the sun gear 22. Due to the eccentric arrangement tion of the intermediate gear 26 with respect to the Kurbelweüenachse A result in each case different numbers of teeth at the transition between the individual toothing areas, so that the gear unit 16 provides a gear ratio when driving through the ring gear 18 and output via the sun gear 22. This translation comprises two transmission stages arranged in series, wherein the first transmission stage is formed by the engagement between the ring gear 18 and the intermediate gear 26, while the second, downstream transmission stage is formed by the engagement between the intermediate gear 26 and the sun gear 22.

The transmission unit 16 is switchable by means of a first clutch device 32 and a second clutch device 34 between a first transmission ratio and a second transmission ratio. The first clutch device 32 is designed as a freewheel and is located between the crankshaft 12 and the sun gear 22. The second clutch device 34 is an electromagnetically actuated friction disk clutch which is arranged between the crankshaft 12 and the ring gear 18. When the second clutch device 34 is engaged, the crankshaft 12 is drive-connected to the ring gear 18.

The crankshaft 12 is led out of the housing 17 of the drive device 10 and is rotatably connected outside of the housing 17 with a vibration damper 36, which has approximately the same radial extension as the pulley 14. Due to the axial

Spacing of the vibration damper 36 from the pulley 14, the vibration damper 36 may have a particularly large radius, whereby a high degree of vibration damping can be achieved According to an alternative embodiment, which is shown in Fig. 3, the vibration damper 36 is disposed in the interior of the housing 17 immediately adjacent to the internal combustion engine 1 1. Again, a large radius of the shock absorber 36 can be displayed.

Torsional vibrations, which may occur as a result of firing of the internal combustion engine 1 1 on the crankshaft 12 are intercepted by the vibration damper 36 and not transmitted via the pulley 14 to the accessory.

During operation of the internal combustion engine 1 1 is first checked by a control device, not shown, whether the speed of the crankshaft 12 is sufficient for proper operation of the auxiliary unit. If the speed is not high enough in this respect, because the internal combustion engine 1 1, for example, is at idle, the second clutch device 34 is closed by appropriate control. The crankshaft 12 is thus fixedly coupled to the ring gear 18 and drives it. The ring gear 18 drives the intermediate gear 26 with a gear ratio to fast. The intermediate gear 26 in turn drives the sun gear 22 with a further translation at speed. The coupled to the sun gear 22 pulley 14 is therefore driven with a two-stage speed translated speed compared to the rotational speed of the crankshaft 12. Since the pulley 14 and the sun gear 22 connected thereto have a higher rotational speed than the crankshaft 12, the freewheel 32 runs.

When the control unit determines that the rotational speed of the crankshaft 12 is sufficient to provide the desired power of the accessory, the second clutch device 34 is opened, whereby the coupling between the crankshaft 12 and the ring gear 18 is canceled. ben will. The speed of the no longer driven ring gear 18 and accordingly also of the intermediate gear 26 and the sun gear 22 decrease so long until the speed of the pulley 14 is equal to the speed of the crankshaft 12. Upon reaching this state locks the freewheel 32, and the sun gear 22 is taken along with the pulley 14 via the freewheel 32 of the crankshaft 12. The pulley 14 is then driven in direct drive with the speed of the crankshaft 12. The differential speed between the ring gear 18 and the crankshaft 12 is received by the opened clutch device 34.

In the case of the two possible modes of operation, the crankshaft 12 is therefore connected to either the ring gear 18 or the sun gear 22 with the aid of the two clutch devices 32, 34.

Due to the uninterrupted switching between a two-stage quickly translated torque transmission and a direct drive through the drive of the auxiliary unit can be optimally adapted to the speed spectrum of the engine 1 1. Due to the provided between the crankshaft 12 and the pulley 14 freewheel 32, it is also possible to shut down the internal combustion engine 1 1 in a hybrid vehicle during an electrical operating mode and to drive the ancillaries with a stationary crankshaft 12 by means of a built-in belt drive generator motor unit. LIST OF REFERENCE NUMBERS

10 drive device

1 1 internal combustion engine

12 crankshaft

14 Pulley

16 gear unit

17 housing

18 ring gear

20 internal toothing of the ring gear

22 sun wheel

24 external toothing of the sun gear

26 intermediate gear

28 External toothing of the intermediate gear

30 Internal toothing of the intermediate gear

31 rolling bearings

32 first coupling device

34 second coupling device

36 vibration absorbers

38 bearing ring

A crankshaft axis

B idler gear axle

Claims

claims

Drive device (10) for an accessory of a motor (1 1), comprising a shaft (12) and a pulley (14) serving as an input element and output element, and a speed-change gear shift unit (16) connected between the shaft (12). 1) and the pulley (14) is effective,

wherein the gear unit (16) comprises a first gear stage having a first gear portion (20) and a second gear portion (28) meshing with the first gear portion (20), and

wherein the gear unit (16) comprises a second gear stage operative in series with the first gear stage, having a third gear portion (30) and a fourth gear portion (24) meshing with the third gear portion (30),

wherein the second and third gear portions (28, 30) are formed on a single common gear member (26) of the gear unit (16).

Device according to claim 1,

By doing so, that is

the common transmission element (26) is an intermediate gear (26) with an internal toothing (30) and an external toothing (28) which form the second and the third toothed region (28, 30) of the gear unit (16).

Device according to claim 2,

characterized in that

the idler gear (26) is eccentric with respect to the shaft (12) and the pulley (14).

Device according to claim 2 or 3,

characterized in that

the intermediate gear (26) is rotatably mounted about a fixed axis (B).

Device according to at least one of the preceding claims, characterized in that

the first toothed region (20) is formed on an input gear (18) of the gear unit (16) and the fourth toothed region (24) is formed on an output gear (22) of the gear unit (16).

Device according to claim 5,

characterized in that

the input gear (18) and the output gear (22) comprise an internally toothed ring gear and an externally toothed sun gear coaxial with the ring gear, an internal toothing (30) of the common gear element (26) meshing with the sun gear and an external toothing (28) of the common gear element (28). 26) meshes with the ring gear.

Apparatus according to claim 5 or 6,

characterized in that

the shaft (12) can be selectively coupled with the input gearwheel (18) or with the output gearwheel (22).

8. Device according to at least one of the preceding claims, characterized in that

between the shaft (12) and the pulley (14) a freewheel (32) is effective.

9. Device according to at least one of the preceding claims, characterized in that

between the shaft (12) and the pulley (14) a

controllable clutch (34), in particular an electromagnetically actuated friction disk clutch, is effective.

10. Device according to at least one of the preceding claims, characterized in that

a vibration damper (36) fixedly coupled to the shaft (12) is provided, which is arranged axially spaced from the pulley (14),

11. The device according to claim 10,

characterized in that

the vibration damper (36) is integrated in a housing (17) of the transmission unit (16).

12. Device according to claim 10,

characterized in that

the vibration damper (36) is arranged outside a housing (17) of the transmission unit (16).