KR101193358B1 - Electrically driven camshaft adjuster - Google Patents

Abstract

The invention relates to an adjusting device (1) for adjusting the position of the rotational angle of the camshaft (3) relative to the crankshaft. This adjusting device comprises a drive part 4 fixedly mounted to the crankshaft and an output part 5 fixedly mounted to the camshaft. The adjusting device 1 includes an adjusting motor 2 as a primary adjusting device and an auxiliary drive 11 as a secondary adjusting device. When the regulating motor 2 fails, the camshaft 3 can be adjusted by the auxiliary drive 11 to a fixed rotational angle position, that is to say an emergency operating position.

Crankshaft, Camshaft, Flywheel, Drive Wheel, Clutch, Brake Disc

Description

Electrically Driven Camshaft Adjuster {ELECTRICALLY DRIVEN CAMSHAFT ADJUSTER}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adjusting device for adjusting the relative rotational angular position of a camshaft with respect to a crankshaft of an internal combustion engine having an adjustment transmission formed of a three-axis transmission, wherein the crankshaft fixed drive unit, the camshaft fixed output unit, and the adjustment motor are adjusted. It includes an adjustment shaft that is connected to the motor shaft.

In order to ensure safe engine starting in internal combustion engines with hydraulic or electric camshaft adjustment systems, the camshaft must be located in the so-called base or emergency operating position. It is usually located in the "retarded" position on the intake camshaft and in the "advanced" position on the exhaust camshaft. In normal operation of the vehicle the camshaft is moved to its respective base position upon engine stop and adjusted to be fixed or fastened thereto.

Conventional rotary piston adjusting devices that are hydraulically actuated, such as vane cells, swing or split vanes, include locking units. This holds the hydraulic adjustment device in the foundation position until sufficient oil pressure is established for adjustment of the camshaft. In the case of engine stalling, the camshaft may be located at an undefined position other than the foundation position.

In a hydraulic camshaft adjustment system having a "crust" foundation position, the camshaft is automatically adjusted to the crustal foundation position at the next start of the internal combustion engine and if the oil pressure is insufficient due to the camshaft friction moment acting against the camshaft rotational direction. If the basic position is the "advanced" position, the camshaft is adjusted to the "advanced" position if the oil pressure on the camshaft friction moment is insufficient. This is most often caused by a compensating spring which generates a moment opposite to the camshaft friction moment.

The conventional method in this hydraulic camshaft adjustment for adjustment to the base position after stalling of the internal combustion engine is not applicable to the electrically driven camshaft adjustment device. These are not necessary as long as the regulating motor system is not damaged and the camshaft can be adjusted to the individual foundation position upon restart or when the internal combustion engine is stopped. However, in the electric coordination motor system, the coordination motor and / or its control unit may fail and thus may not reach the base position.

In German patent DE 41 10 195 A1 the device for the adjustment of the rotational angular position between the crankshaft and the camshaft of an internal combustion engine is described as having an adjustment transmission formed by a three-axis transmission, which is the drive shaft and the camshaft connected to the crankshaft. It includes an output shaft connected to and an adjustment shaft connected to the electric adjustment motor, and there is a static gear ratio (I ₀ ) between the drive shaft and the output shaft in the stationary adjustment shaft, which is the adjustment direction and shift (minus or plus shift) of the cam shaft. Is determined on an individual basis or in an emergency operating position.

In each adjustment device, the camshaft position needs to be easily moved and set accurately. If a limitation of the adjustment angle is provided when the regulating motor system fails, the function of the internal combustion engine can be at least temporarily achieved. However, there is no criterion for the arrival of the basic or emergency operating position in such a situation. In each configuration the foundation position must be provided at one of the two end positions of the camshaft adjustment device. The camshaft adjustment always operates towards either the forward or the latent stop.

However, it is desirable to select any central position as the base position under certain thermodynamic criteria.

It is therefore an object of the present invention to provide an adjusting device for adjusting the rotational angular position of the camshaft with respect to the crankshaft of the internal combustion engine, which can be adjusted to any position, in particular a central emergency operating position in the event of a failure of the regulating motor. To provide. The adjusting device should then be maintained in this position.

According to the invention, the above object is achieved in the case of an internal combustion engine having the features of the preamble of claim 1, wherein the adjusting device comprises an adjusting motor as the primary adjusting device and an auxiliary drive as the secondary adjusting device, and thus the auxiliary drive. The camshaft adjusts the camshaft to a fixed angle of rotation, that is, an emergency operating position in case of an adjustment motor failure.

The secondary drive can be formed in an active or passive manner. Active secondary drives require controllers, switches and actuators. Auxiliary drives are only connected when needed and therefore take energy. At this time, the actual deflection for the emergency operating position is identified, the target energy supply is derived from the actual deflection, and the emergency operating position is controlled. It is desirable when a connection occurs through each working medium of the secondary drive. This may relate to a pneumatic motor in the auxiliary motor, for example separated from the adjusting shaft in a steady state via a spring. If the regulating motor fails, the connection is made via compressed air.

The passive auxiliary drive is permanently combined with the main drive. The base position of the camshaft corresponds to the neutral state of a three-axis transmission system with an auxiliary drive. In normal operation, with each rotation angle adjustment from the base position, energy is supplied into the auxiliary drive. If the main drive operating with respect to the auxiliary drive fails, the auxiliary drive adjusts the rotational angular position of the camshaft to the emergency operating position. For a passive auxiliary drive, only one actuator is needed. Controllers and switches can be omitted.

It is desirable that no energy is supplied from the active auxiliary drive to the auxiliary drive during normal operation, so that no reaction in the form of vibration usually occurs. The advantage of a passive auxiliary drive is that it is simpler and more economical. Two auxiliary drives can be connected to the hybrid drive, in which manual adjustment, which can be carried out via friction, can be carried out in one direction, the adjustment being in the opposite direction under the connection of an active system acting in only one direction. Happens.

Auxiliary drives can be operated in two main ways. Firstly, it can act on the adjusting shaft, and torque support occurs on the chainwheel or camshaft. At this time, a small moment of the auxiliary drive is required, but the auxiliary drive must provide a large rotational speed. For example, five rotations of the adjustment shaft are required at a deceleration of the adjustment mechanism of 1:60 at a maximum camshaft adjustment, typically 30 degrees.

The auxiliary drive can then act directly on the chainwheel or the camshaft, where torque support occurs between each other. In this case, a large moment is needed. However, the friction effect or bearing damage at this time has a greater influence on the adjustment moment between the camshaft and the chainwheel.

Specifically, the auxiliary drive is for example by torsion springs, hydraulic motors, pneumatic motors, electrical auxiliary motors, brakes, centrifugal motors, three-axis transmissions, switchable freewheels, flywheels or by using the moment of inertia of the regulating motor itself. Can be implemented.

If the auxiliary drive is formed of a torsion spring, it is arranged between the adjusting shaft and the chain wheel or between the chain wheel and the cam shaft. These may be formed as torsion springs having a double acting or reducing gear. These systems require low technical cost and the switching time is design dependent.

If the auxiliary drive is formed of a hydraulic motor, this can produce a large moment. The switching time depends on the viscosity of the operating medium, for example oil, required for the operation. This disadvantage is compensated for by small reactions in normal operation as well as in failure, since the auxiliary drive can be operated without oil. Auxiliary drives need energy only if they fail. If the auxiliary drive is formed of a pneumatic motor, the dependence of the switching time on viscosity is omitted. However, if the electric motor fails, the efficiency is lower than that of the hydraulic motor.

The auxiliary drive formed as an electrical actuator can be, for example, an emergency actuating coil or a combined electric motor, but it can also be a battery or a capacitor, which shows a short switching time and uses less energy if necessary. If the auxiliary drive is formed, for example, as a brake in combination with a three-axis transmission, or as a brake lining or eddy current brake, it has the same advantages as an electrical auxiliary motor at smaller reactions to normal operation.

It is also simple to implement an auxiliary drive in the form of an adjusting shaft with a flywheel. These systems have a small response in case of failure. Instead, this small response to normal operation can be detected because of the large inertia.

The auxiliary drive may be formed of a centrifugal motor. A passive or active system can be implemented, the switching time of which depends on the design and the camshaft speed. In the event of a normal failure there is little reaction, but in normal operation the response increases with the rotation of the camshaft. This mechanism is operable as soon as the drive wheel exceeds a predetermined minimum speed.

Arrangement of the auxiliary drive between the drive unit and the output unit provided according to claim 2 may be performed spatially, but is not limited thereto. Rather, it represents an arrangement for power flow as can be seen from some of the particularly preferred embodiments described above in detail. For example, if the regulating motor consists of an electric motor, it is arranged axially before the camshaft.

In summary, the passive system is advantageous in structure due to its simplicity, but disadvantages in normal operation due to power consumption and power dissipation under permanent deflection. Active systems avoid these drawbacks but are complex in structure.

If a secondary drive is used in case of failure, maintenance of the emergency operating position is possible in three different ways. Through active control, for example through force coupling such as switchable flywheels, or through form coupling with locking pins acting axially or radially and operating with oil pressure, air pressure or electromagnetically It is possible through.

An overload clutch can be arranged between the regulating motor and the camshaft to protect the regulating shaft and / or the regulating mechanism from overload when the regulating shaft of the electrical regulating motor is suddenly blocked. Such overload clutches can be formed, for example, as slide clutches or shear pins.

Through the solution according to the invention, the stability of the adjusting device is substantially increased. Thus, it is possible to operate a simply constructed passive system or to use an active system with a small response to operation.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

1 is a schematic view of an adjusting device with a regulating motor fixed to a cylinder head.

2 is a schematic diagram of an adjusting device having an adjusting motor formed of a flywheel.

3A is a schematic illustration of an auxiliary drive formed of a torsion spring and arranged between the chainwheel and the camshaft.

3b is a schematic view of an auxiliary drive formed with a spring and acting between the chainwheel and the adjustment shaft;

4 is a schematic view of an adjusting device having a pneumatic or hydraulic motor arranged between the adjusting shaft and the chain wheel.

Fig. 5A is a cross sectional view of an auxiliary drive formed of a centrifugal force motor located in the foundation position.

Fig. 5B is a cross sectional view of an auxiliary drive formed of a centrifugal motor, which is not located in the foundation position.

6A is a schematic diagram of an adjusting device having an auxiliary drive and a brake arranged therein;

6B is a schematic diagram of an adjusting device having an auxiliary drive and a brake arranged externally.

7A is a schematic diagram of an adjustment device having an auxiliary drive powered by a capacitor.

7B is a schematic diagram of an adjustment device having an auxiliary drive powered by an external voltage source.

7C is a schematic diagram of an adjusting device having an external auxiliary drive formed of an electric motor.

8 is a schematic view of an adjusting device having an overload clutch.

9 is a cross-sectional view of the adjustment device with the locking unit.

1 shows an embodiment of the invention as an adjusting device having an adjusting transmission 13 and an adjusting motor 2, which essentially consists of a rotor 8 and a stator 9. The adjusting device is used for adjusting the rotational angular position between the crankshaft and the camshaft 3 of the internal combustion engine, not shown. The adjustment transmission 13 is formed as a three-axis transmission having a drive unit 4, an output unit 5, and an adjustment shaft 6. The drive unit 4 is fixedly connected to the drive wheel 7, and is thereby fixedly connected to the crankshaft by a gear wheel, a toothed belt or a toothed chain, not shown. The output part 5 is fixedly connected to the camshaft 3 and the adjustment shaft 6 is fixedly connected to the rotor 8 of the regulating motor 2. The stator 9 of the regulating motor 2 is fixedly connected to the cylinder head 10 and is stationary. The camshaft 3 has a basic or emergency operating position, which must be achieved for safe starting and limited operation. Since the regulating motor 2 adjusts the camshaft 3 to the basic position at the time of stopping or restarting the internal combustion engine, the regulating motor 2 is not damaged and this is performed even without the auxiliary drive 11 after the stalling of the internal combustion engine. (See Figure 2). However, without the auxiliary drive 11, control of the rotational angular position in the defective adjustment motor 2 is no longer possible.

2 shows an auxiliary drive 11 designed as a flywheel 12, which is arranged directly on the adjusting shaft 6 and is thus fixedly connected to the adjusting motor 2. The drive wheel 7 thereby interacts with the adjustment shaft 6 on the one hand and with the camshaft 3 on the other hand. The flywheel 12 can be integrated into the adjusting device 1 to save space, and it is particularly preferable to arrange the mass as far as possible from the axis of rotation so that the smallest mass possible at the preset moment of inertia can be used. However, if the rotor 8 of the regulating motor 2 already has a larger mass, then an additional flywheel 12 may optionally be present if the rotor 8, which can also act as a torque reservoir, has a sufficiently high torque. Can be removed.

In figure 3a an auxiliary drive 11 is shown which is formed from a torsional spring 14 acting dually. This acts between the camshaft 3 and the drive wheel 7. At this time, the base position is formed by the rotation angle between the camshaft position and the drive wheel position, and there is a moment equilibrium state without the influence of the adjusting motor 2 at the rotation angle. In normal operation the electric regulating motor 2 changes the equilibrium state and thus deflects the torsion spring 14. At this time, if the regulating motor 2 fails, the torsion spring is released from deflection to the rest position. Accordingly, the torsion springs 14 can act in one or in duplicate. In FIG. 3B a spring 18 is arranged between the drive wheel 7 and the adjustment shaft 6. At this time, the moment is transmitted from the adjusting shaft 6 through the reduction gear 15, otherwise the acting mechanism corresponds to the acting mechanism of Fig. 3A. In particular here a single acting spring 18 can be used, or a spiral spring can be used.

4 shows an adjusting device 1 with an auxiliary drive 11 formed of a pneumatic motor 16. The housing 20 of the pneumatic motor is rotatably connected to the drive wheel 7 by the chamber, and the pneumatic motor rotor 21 is rotatably connected to the adjustment shaft 6. As soon as the regulating motor 2 fails, the pneumatic motor 16 can continue to delegate its function as an active drive, or can adjust the regulating device 1 only to the basic position, as in the passive auxiliary drive, the foundation position being It remains fixed via the locking unit 19 (Fig. 9). Possible configurations of the pneumatic motor 16 are, for example, multi disk or gear motors.

The auxiliary drive 11 may also be formed as a hydraulic motor 17 instead of a pneumatic motor 16, whereby a roller vane pump, an internal gear pump or a flow pump is particularly suitable.

5A and 5B show a centrifugal force motor 22 consisting essentially of an internal gear 23 having a connecting link 24, which is fixed on the drive wheel so as to be rotatable relative to the drive wheel 7.

The internal gear 23 is positioned on the planetary gear 25, and the planetary gear 25 is disposed on the web shaft 26, which is firmly connected to the drive wheel 7, and the sun gear disposed on the adjustment shaft 6. Works with (27). In the connecting link 24, the run case 28 is guided through a mass 30 rigidly connected to it, the mass 30 being simultaneously guided in the long hole 29, the long hole into the drive wheel 7. It is integrated and extends in the radial direction. A slide block may be disposed instead of the run case 28. If the connecting link 24 does not extend exactly in the radial direction and the base position of the device corresponds to the run case position as far as possible in the radial direction from the midpoint of the internal gear 23, the link 24 may be basically of arbitrary shape. have. In particular, the connection link 24 is preferably configured in a parabolic or V shape.

The centrifugal motor 22 is operable as soon as the drive wheel 7 reaches the minimum speed. At this time, when the adjustment motor 2 starts the rotation angle adjustment, the motor rotates the drive wheel 7 via the adjustment shaft 6 and the sun gear 27. At the same time, the inner gear 23 is rotated through engagement with the planetary gear 25, through which the mass 30 is pulled radially inward through the connecting link (see FIG. 5B). When the regulating motor 2 fails, the mass 30 moves to the position furthest outward due to the centrifugal force. The output flow is reversed and the adjustment device 1 is adjusted to the foundation position. The adjusting device 1 can be fixed there by the locking unit 19 (Fig. 9) if necessary.

In Figs. 6A and 6B, the auxiliary drive 11 is formed of a brake 31, which in Fig. 5A is a brake 31 which is integrated into the electric regulating motor. It may for example consist of a short circuit brake coil and brakes the regulating motor via induction. Another possibility may be a separate coil that may be used as the emergency actuation coil 35. The brake 31 may also be arranged externally, for example as a brake disc 32 arranged on the adjustment shaft 32 (FIG. 6B), which brake or hydraulically actuated electromagnetically or electromagnetically upon failure. Braking through). Another possible embodiment of the brake 31 is a band, disc or shoe brake. The brake 31 can act directly on the output 5 and on the camshaft 3 or indirectly on an axis connected to the adjustment shaft, for example by a clutch.

7A and 7B show an auxiliary drive 11 formed of an electric motor 34, the rotor of which is formed by the rotor of the regulating motor 2. A separate coil is performed as the emergency acting coil 35 around the stator of the electric motor 34. The energy supply of the electric motor 34 is stably provided through the capacitor 36 or the external power unit 37. A battery may be used instead of the capacitor 36. Alternatively, the drive may be performed by a belt or chain. It is clear from FIG. 7C that the electric motor 34 can be implemented as an external component.

8 shows an adjusting device 1 with an adjusting motor 2, whereby an overload clutch 38 is arranged between the adjusting motor 2 and the output shaft 5. If the adjusting shaft 6 is blocked, then the blocking does not have any suppressive effect on the camshaft 3. Preferably, the auxiliary drive 11 is arranged behind the overload clutch 38, so that the failed adjusting device 2 can not operate opposite to the auxiliary drive 11. The overload clutch 38 can be selected as a clutch known in the art, for example the clutch discs 40, 41 are configured to be actuated or magnetically actuated by the compression spring 39.

9 illustratively shows a possible arrangement of the locking unit 19, which is essential in the manual system described above to fix the angle of rotation in the event of a failure. The locking unit 19 is here formed of a spring element operating in the radial direction. Locking and releasing is done through the oil pressure supplied by the oil channel 42 in this figure. Alternatively, the locking unit 19 may use centrifugal, magnetic or rotational pulses of the adjusting shaft for operation. The arrangement of the locking unit 19 can be done in the axial direction and the radial direction in the adjusting device.

In summary, if the adjusting device 2 fails, the internal combustion engine is controlled between the crankshaft and the camshaft 3 because active or passive return is controlled by the configuration of the auxiliary drive 11 according to the invention to the basic position. It can be operated more reliably by the rotation angle.

1. Adjustment device

2. adjustable motor

3. Camshaft

4. Driving part

5. Output

6. Adjustable shaft

7. Drive wheel

8. Rotor

9. Stator

10. Cylinder head

11. Secondary drive

12. Flywheel

13. Fixed gearbox

14. Torsion Spring

15. Reduction Gear

16. Pneumatic motor

17. Hydraulic motor

18. Spring

19. Locking Unit

20. Housing

21. Pneumatic motor rotor

22. Centrifugal force motor

23. internal gear

24. Link

25. Planetary Gear

26. Web shaft

27. Sun Gear

28.Run case

29. Longevity

30. Mass

31.Brake

32. Brake Disc

33. Brake Block

34. Electric motor

35. Emergency operation coil

36. Capacitors

37. External power unit

38. Overload Clutch

39. Compression Spring

40. Clutch Disc

41. Clutch Disc

42. Oil Channel

Claims (20)

delete delete delete delete In the adjusting device 1 for adjusting the relative rotation angle position of the camshaft 3 with respect to the crankshaft of the internal combustion engine, comprising a drive section 4 fixed to the crankshaft and an output section 5 fixed to the camshaft. ,  The adjusting device 1 comprises an adjusting motor 2 as a primary adjusting device and an auxiliary drive 11 as a secondary adjusting device, in which the camshaft 3 causes the auxiliary drive 11 to fail when the adjusting motor 2 fails. Can be adjusted to a fixed angle of rotation, ie emergency operating position, The auxiliary drive (11) is permanently coupled with the regulating motor (2), characterized in that the regulating device (2) adjusts the rotation angle to the emergency operating position without external energy supply in the event of a failure. 6. The adjusting device according to claim 5, wherein the auxiliary drive (11) is formed of a torsion spring (14) acting singly or dually. 6. The adjusting device according to claim 5, wherein the auxiliary drive (11) is formed of a torsion spring (14) with a reduction gear. 8. The adjustment according to claim 6, wherein the torsion springs 14 are pretensioned at engine start, are separated in a pretensioned state, and are engaged by actuators when the regulating motor 2 fails. Device. 6. The adjusting device according to claim 5, wherein the auxiliary drive (11) is formed of a centrifugal force motor (22). 6. The adjusting device according to claim 5, wherein the adjusting motor (2) is formed of an electric motor and the rotor (8) of the electric motor simultaneously forms an auxiliary drive (11). 6. The adjusting device according to claim 5, wherein the auxiliary drive (11) is formed of a flywheel (12). 7. The auxiliary drive (11) according to claim 5, characterized in that the auxiliary drive (11) is not permanently coupled to the regulating motor (2) and adjusts the rotation angle to the emergency operating position by external energy supply when the regulating motor (2) has failed. Adjusting device. 6. The adjusting device (1) according to claim 5, wherein the adjusting device (1) comprises an adjusting transmission (13) formed by a three-axis transmission, and the auxiliary drive (11) is formed by a brake (31) acting on one of the members of the three-axis transmission. Adjusting device, characterized in that. 14. The adjusting device according to claim 13, wherein the brake (31) is formed of a disk arranged in the adjusting motor (2). 13. The adjusting device according to claim 12, wherein the auxiliary drive (11) is formed of a hydraulic motor (17) or a pneumatic motor (16). 13. The adjusting device according to claim 12, wherein the auxiliary drive (11) is formed of an electric auxiliary motor (34) or an emergency actuating coil (35). 17. The adjusting device according to claim 16, wherein the energy supply of the electric auxiliary motor 34 or the emergency actuating coil 35 is carried out through a capacitor 36, an external power unit 37, a battery, a chain or a belt. . 6. The adjusting device according to claim 5, wherein the auxiliary drive (11) is formed from a combination of two auxiliary drives, each of which acts oppositely. 6. The adjusting device according to claim 5, wherein the adjusting device further comprises an overload clutch (38), wherein the overload clutch (38) is arranged between the adjusting motor (2) and the output part (5). 20. The adjusting device according to claim 19, wherein the overload clutch (38) is formed of a slide clutch or a shear pin.

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