WO2011124193A1

WO2011124193A1 - Crankshaft pulley

Info

Publication number: WO2011124193A1
Application number: PCT/DE2011/000254
Authority: WO
Inventors: Peter Greb
Original assignee: Schaeffler Technologies Gmbh & Co. Kg
Priority date: 2010-04-06
Filing date: 2011-03-10
Publication date: 2011-10-13
Also published as: DE112011101221A5; DE102011013478A1

Abstract

The invention relates to a crankshaft pulley for transferring a torque between a crankshaft and a belt drive, comprising a pulley freewheel. The invention is characterized in that the pulley freewheel in the crankshaft pulley is combined with a coupling that can be actuated by an actuating freewheel. The pulley freewheel can be bridged by the coupling.

Description

Kurbelwelienriemenscheibe

The invention relates to a crankshaft pulley for transmitting a torque between a crankshaft and a belt drive, with a pulley freewheel.

From the German patent application DE 195 35 889 A1 discloses a one-way clutch is known, which is arranged between a pulley and a shaft. The known overrunning clutch is suitable for driving a generator and is part of a pulley, which serves to drive the generator. By using the one-way clutch an internal damping is made possible, so that the torque transmission of the traction mechanism is improved. European Patent EP 0 980 479 B1 discloses a belt drive system having a generator clutch freewheel clutch comprising a torsion coil spring and a one-way clutch mechanism. As a result, the driving torques of the generator pulley can be transmitted to a hub yielding. In addition, the generator pulley can be uncoupled from the hub in one direction. From the German patent DE 196 36 628 C1 a freewheel with a clamping body is known, which is formed by a circumferentially extending gap, elastically deformed coil spring. European Patent EP 0 782 674 B1 discloses a crank-shaft decoupler with a directionally switched clutch which serves to selectively transmit rotational forces between a mounting hub and a pulley. German Offenlegungsschrift DE 10 2005 029 351 A1 discloses a drive wheel for driving an auxiliary unit of an internal combustion engine with a damping device.

The object of the invention is to provide a space-neutral solution for a decoupled from the crankshaft crankshaft pulley according to the preamble of claim 1. In this case, the crankshaft pulley according to the invention should in particular a start-stop operation, a stationary climate and generator operation, preferably with a pulse starting possibility including Kurbelwellentilger, and / or damping of rotational irregularities in the belt drive, allow.

The object is achieved in a crankshaft pulley for transmitting a torque between a crankshaft and a belt drive, with a pulley freewheel, characterized in that the pulley freewheel in the crank pulley with a is combined by an actuated clutch operable clutch, through which the pulley freewheel can be bridged. For example, the pulley freewheel is designed to lock when the crankshaft is rotating in the forward direction of rotation. The direction of forward rotation of the crankshaft is, for example, referred to as the forward direction of rotation when the crankshaft is driven by an internal combustion engine of a motor vehicle. The pulley freewheel has a reverse direction. In the opposite direction of rotation of the freewheel acts. The invention provides a compact crankshaft pulley, which allows the use of a starter generator and the function of a stationary air conditioning, in which the starter generator drives the crankshaft. The solution according to the invention has the particular advantage that it does not require a separate power supply or control of an actuator system. Due to its design, the crankshaft pulley can assume two basic states. The first basic state covers the operating states generator operation and stationary air conditioning. The second basic state is used to start the internal combustion engine. In the first basic state, the pulley track or belt pulley or belt track is connected to the crankshaft via the pulley freewheel. By decoupling in the freewheeling direction of the pulley freewheel torque can not be transmitted to the crankshaft of the pulley or pulley track when it is driven by the starter generator via the belt drive. An air conditioning compressor is additionally connected to the belt drive, so that the operating condition of stationary air conditioning can be displayed. In order to start the internal combustion engine, which is also referred to as an internal combustion engine, in the second basic state, the pulley freewheel is bridged with the clutch, so that the starter generator can transmit a torque to the crankshaft.

A preferred embodiment of the crankshaft pulley is characterized in that the coupling is designed positively. The clutch is preferably designed as a dog clutch with two clutch partners, which are brought into positive engagement with each other for torque transmission. To generate the positive connection, one of the coupling partners is preferably moved in the axial direction toward the other coupling partner in order to connect the two coupling partners in a rotationally fixed manner to one another.

Another preferred embodiment of the crankshaft pulley is characterized in that the clutch is actuated by a ramp mechanism. The ramp mechanism is operated, for example, when the pulley or a pulley track rotates in the reverse direction. Another preferred embodiment of the crankshaft pulley is characterized in that the ramp mechanism via the actuating freewheel to a fixed housing part can be connected or connected. The stationary housing part is preferably a crankcase in the engine compartment of the motor vehicle.

A further preferred embodiment of the crankshaft pulley is characterized in that the ramp mechanism has at least one ramp with a ramp valley. The ramp mechanism preferably comprises a plurality of ramps which are uniformly distributed in the circumferential direction.

Another preferred embodiment of the crankshaft pulley is characterized in that the ramp mechanism has at least one plateau with a shoulder to a maximum of the ramp. The ramp with the ramp valley and the plateau with the shoulder are preferably arranged in the circumferential direction in a recurring order.

Another preferred embodiment of the crankshaft pulley is characterized in that the clutch is biased by a spring means in an open position. In stand-alone mode or generator mode, the coupling is open. To start the internal combustion engine via the starter generator, the clutch is closed at least for the duration of the starting process.

Another preferred embodiment of the crankshaft pulley is characterized in that the coupling is designed to be self-opening by the spring device. With the help of the ramp mechanism, the clutch is closed at least for the duration of a startup process for starting the internal combustion engine.

Another preferred embodiment of the crankshaft pulley is characterized in that the biasing force of the spring means is supported on one or the fixed housing part. The stationary housing part is preferably the crankcase in the engine compartment of the motor vehicle.

A further preferred exemplary embodiment of the crankshaft pulley is characterized in that the clutch comprises a coupling ring which, with the aid of pretensioned ten leaf springs is connected to a pulley track. The leaf springs represent the previously described spring device.

Further advantages, features and details of the invention will become apparent from the following description in which, with reference to the drawings, various embodiments are described in detail. Show it:

1 shows a crankshaft pulley according to the invention in a first longitudinal section;

FIG. 2 shows the crankshaft pulley from FIG. 1 in a second longitudinal section;

3 shows the crankshaft pulley of Figures 1 and 2 in cross section and

Figure 4 shows the representation of different operating modes of the crankshaft pulley of Figures 1 to 3 as a linear model.

FIGS. 1 to 3 show a crankshaft pulley 1 according to the invention in various sectional views. The crankshaft pulley 1 includes a pulley track 2, which is also referred to as a pulley or belt track for a short time and serves to couple a belt (not shown) of a belt drive to a belt starter generator and, alternatively, additionally to an air conditioning compressor. The crankshaft pulley 1 is attached to a crankshaft 4 of a motor vehicle by means of a central screw 5, which is also referred to as a crankshaft screw. The crankshaft 4 is driven by an internal combustion engine, which is also referred to as an internal combustion engine.

According to one essential aspect of the invention, a pulley freewheel 8, a clutch 10 and a torsional vibration damping device 12, which comprises an absorber mass 14, are integrated into the crankshaft pulley 1. The clutch 10 is positively designed as a dog clutch. About the clutch 10, the pulley freewheel 8 can be bridged to connect the pulley track 2 as needed with the crankshaft 4. The central screw 5 comprises a screw head 16, from which a screw shaft 17 extends with a thread. The screw shaft 17 is screwed into a central threaded blind hole of the crankshaft 4. A freewheel inner ring 18 of the pulley freewheel 8 is fixedly connected to the crankshaft 4 by means of the central screw 5. The freewheel inner ring has radially outer bearing races for different rolling elements of a bearing device 20. The bearing device 20 is designed as a combined roller / ball bearings, by which a freewheel outer ring 22 is rotatably mounted on the central screw 5 and the crankshaft 4.

In the axial direction adjacent to the bearing device 20 22 freewheel rollers 23 of the pulley freewheel 8 are arranged in the radial direction between the freewheel inner ring 18 and the freewheel outer ring. The pulley freewheel 8 is preferably designed as a roller freewheel with a locking direction and a freewheeling direction. The pulley track 2 can be driven via the pulley freewheel 8 in the reverse direction. In the opposite direction of rotation opens the pulley freewheel 8, so that no torque can be transmitted. With the clutch 10, the pulley freewheel 8 can be bridged.

From the freewheel inner ring 18, a flange 24 extends radially outward. On the flange 24 of the freewheel inner ring 18, a Tilgerflansch 26 is fastened by means of rivet connection elements 25, which extends from the rivet connection element 25 radially outwardly. The Tilgerflansch 26 passes radially outward into a hollow cylinder section 27, which is arranged parallel to the axis of rotation of the crankshaft pulley 1. On the hollow cylinder portion 27 of the Tilgerflanschs 26, the absorber mass 14 is mounted with the interposition of a rubber track 28.

The coupling 10 comprises a first coupling partner 31 which can be positively connected to a second coupling partner 32 in order to enable torque transmission between the two coupling partners 31, 32. The first coupling partner 31 is attached to the flange 24 of the freewheel inner ring 18. The second coupling partner 32 is designed as a coupling ring 34 and movable in the axial direction relative to the first coupling partner 31 in order to produce or cancel the positive connection required for torque transmission. The coupling ring 34 is biased by a spring means 35 in its open position in which no torque between the coupling partners 31, 32 is transmitted. The spring device 35 comprises a plurality of circumferentially distributed leaf springs 36 which are each connected by means of Nietverbindungselementen 37 at one end fixed to the pulley track 2. The other ends of the leaf springs 36 are fastened to the coupling ring 34 by means of rivet connection elements 38. The leaf springs 36 provide a rotationally fixed connection between the coupling ring 34 and the pulley track 2. In addition, the leaf spring members 36 allow axial movement of the coupling ring 34 relative to the pulley track 2 in the axial direction.

The leaf springs 36 are designed and arranged so that the coupling ring 34 is biased in its open position. The coupling ring 34 can be displaced via a pressure piece 39 by means of a ramp mechanism 40 from its open position to its closed position. The pressure piece 33 can be rotationally fixed by means of a toothing at its radially inner circumference, but axially displaceable, be connected to the freewheel outer ring 22. The clutch 10 is actuated via the ramp mechanism 40 by means of an actuating freewheel 45, which is connected to a stationary housing part, which is designated by 50 in FIG. The stationary housing part 50 is preferably a crankcase in the engine compartment of a motor vehicle.

In the normal direction of rotation of the crankshaft 4 or the pulley track 2 of the operating freewheel 45, for example, in the operating conditions of generator operation and stationary air conditioning, overhauled, so that the ramp mechanism 40 is inactive. When the starter generator is rotated backwards in the belt drive, the operating freewheel 45 locks and the ramp mechanism 40 converts the rotation of the pulley track 2 into an axial movement, which is supported on the one hand on the crankcase 45 and on the other hand acts on the spring device 35 via the pressure piece 39 the axially movable coupling ring 34 of the dog clutch 10 is connected.

The support of the axial force on the crankcase 50 is not critical, since the relevant components do not rotate relative to each other in this state. In addition to the spring device 35, a relatively weak (not shown) additional spring may be provided which slightly pushes a ramp disc of the ramp mechanism 40 in normal operation away from the crankcase 50 in order to avoid drag losses. When the dog clutch 10 tooth on tooth or claw is on claw, it closes under biasing force of the spring means 35 in a renewed forward rotation of the pulley track 2. Otherwise, the dog clutch 10 is closed directly upon actuation of the operating freewheel 45 via the ramp mechanism 40, so that the

Internal combustion engine can be started via the belt drive from the starter generator.

The ramp mechanism 40 comprises, as is indicated in greatly simplified form in FIG. 4, a ramp with a ramp valley and a ramp plateau, which is offset slightly downwards relative to the maximum of the ramp. The ramp plateau drops steeply into the following Rampental. The group Rampental, ramp, heel, Rampenplateau can also be several times distributed over the circumference provided on the ramp mechanism.

In the operating states of generator operation and stationary air conditioning, the pressure piece 39 is held as a counter partner of the ramp mechanism 40 by the biasing force of the spring means 35 in the ramp valley. In a reverse rotation of the pulley track 2, the pressure piece 39 is moved along the ramp and performs an axial movement. At the end of the ramp, the pressure piece 39 is moved by the spring means 35 to the slightly lower ramp plateau. The heel prevents unwanted slippage or retraction along the ramp.

Now, the starter generator is rotated in the opposite direction, so that the internal combustion engine can be started. Due to torsional vibrations, the pressure piece 39 can rotate with respect to the ramp part away from the ramp, since the actuating freewheel 45 prevents the pressure piece 39 from entraining the ramp part by friction. Torsional vibrations in the other direction cause the pressure piece 39 entrains the ramp part due to friction. As a result, the pressure piece 39 moves along the Rampenplateaus to the end. There it is pressed by the spring device 35 back into the Rampental and opens the dog clutch.

The length of the ramp plateau is designed in dependence on the number and the size of the torsional vibrations, which are known for example from simulations of tests, so that the dog clutch 10 remains securely meshed, at least for the duration of the starting process. When the engine is started and runs automatically, the pressure piece 39 is moved due to torsional vibrations further up to the Rampental. When the internal combustion engine is running, it can transmit torque via the pulley freewheel 8 to the pulley track 2 and thus to the starter generator connected thereto for charging the battery. Rotationsuniformity of the internal combustion engine are thereby damped in that the pulley freewheel 8 transmits only the acceleration phases of the rotational irregularities, but in the deceleration phases is overtaken by the inertia of the belt drive. As a result, the belt and the units connected to it are subjected to less load than with a rigid connection. This operating state is also referred to as generator operation.

FIG. 4 shows various operating modes I to IV of the crankshaft pulley 1 from FIGS. 1 to 3 as a linear model. In stationary climate mode I, the ramp mechanism 40 is held by the spring 35 in the ramp valley and taken with the pulley 2. Through the pulley freewheel 8, the crankshaft 4 stops when the internal combustion engine is switched off. The pulley freewheel 8 and the operating freewheel 45 overtake.

When meshing II the starter generator and thus the pulley 2 are rotated backwards. In this case, the pulley freewheel 8 blocked, so that the crankshaft 4 rotates backwards. The ramp mechanism 40 becomes active because the operating freewheel 45 is also blocked. The dog clutch 10 spurts, that is, the coupling partners are engaged. When the dog clutch 10 is tooth to tooth or claw to claw, then the spring 35 is biased. The spring bias causes the dog clutch 10 completely einspurt in a reversal of direction or the clutch partners fully engaged.

In a combustion starter III takes the starter generator through the closed dog clutch 10, the crankshaft 4 with. On-the-fly rotational irregularities cause the ramp mechanism 40 to lead in blocks to the end of the ramp plateau. There, the dog clutch 10 spurts out again, that is, the clutch partners are released from their engagement. By a corresponding inclination of the jaws of the dog clutch 10, an undesirable distortion of the pulley arrow 8 and the dog clutch 10 can be excluded. The biasing force of the spring 35 is chosen so large that occurring during operation Reibwertschwankungen be compensated. In the generator mode IV, the internal combustion engine, which is also referred to as a combustor, takes the pulley 2 and thus, via the pulley freewheel 8, the starter generator during acceleration. If the combustor retards, the pulley freewheel 8 makes it possible for the pulley 2 and the towed ramp mechanism 40 to be overtaken. The belt pulley freewheel 8 dampens vibrations in the belt drive.

List of accessories for crankshaft pulley

Pulley groove

crankshaft

central screw

Pulley one-way

clutch

Torsional vibration damping device

absorber mass

screw head

screw shaft

Freewheel inner ring

Storage facility

Freewheel outer ring

Idlers

flange

Nietverbindungselement

Tilgerflansch

Hollow cylinder section

rubber track

first coupling partner

second coupling partner

coupling ring

spring means

leaf springs

Nietverbindungselemente

Pressure piece

ramp mechanism

Operation freewheel

fixed housing part

Claims

claims

A crankshaft pulley for transmitting torque between a crankshaft (4) and a belt drive, comprising a pulley freewheel (8), characterized in that the pulley freewheel (8) in the crankshaft pulley (18) is operable with a clutch (45) operable by an actuation freewheel (45). 10) is combined, by which the pulley freewheel (8) can be bridged.

2. crankshaft pulley according to claim 1, characterized in that the coupling (10) is designed positively.

3. crankshaft pulley according to one of the preceding claims, characterized in that the coupling (10) by a ramp mechanism (40) is actuated.

4. crankshaft pulley according to claim 3, characterized in that the ramp mechanism (40) via the actuating freewheel (45) to a fixed housing part (50) can be connected or connected.

5. crankshaft pulley according to claim 3 or 4, characterized in that the ramp mechanism (40) has at least one ramp with a ramp valley.

6. crankshaft pulley according to claim 5, characterized in that the ramp mechanism (40) has at least one plateau with a shoulder to a maximum of the ramp.

7. crankshaft pulley according to one of the preceding claims, characterized in that the coupling (10) is biased by a spring means (35) in an open position.

8. crankshaft pulley according to claim 7, characterized in that the

Clutch (10) by the spring device (35) is self-opening executed.

9. crankshaft pulley according to claim 7 or 8, characterized in that the biasing force of the spring means (35) on one or the fixed housing part (50) is supported.

10. crankshaft pulley according to one of the preceding claims, characterized in that the coupling (10) comprises a coupling ring (34) which is connected by means of prestressed leaf springs (36) to a pulley track (2).