JP2005532503A - Cam shaft adjusting device with electric drive - Google Patents

Abstract

The present invention is an electrical adjustment device for the rotational angular position of the camshaft (3) relative to the crankshaft of the internal combustion engine, provided with an adjustment transmission device (1), the adjustment transmission device (1 ) Is formed as a triaxial transmission device and is coupled to the crankshaft stationary drive portion (4), the camshaft stationary driven portion (5), and the electric adjustment motor (2) so as not to rotate relative to each other. The adjusting shaft (6), the adjusting motor (2) has a permanent magnet rotor (8) and a stationary stator, and a drive part (4) and a driven part (5). Between the fixed transmission device and the camshaft (3) as the positive transmission device or the negative transmission device of the adjustment transmission device (1). ), The adjustment direction to the basic position located on the early or late side On of the type so as to define.
Based on an appropriate structural configuration of the adjusting transmission (1), the following fixed transmission transmission ratio i ₀ can be realized, and the fixed transmission transmission ratio i ₀ can accelerate the camshaft (3). The basic positions on the side and the lag side can be achieved when the adjusting transmission (1) is rotated by simply braking the adjusting shaft (6), and braking of the adjusting shaft (6) is advantageous. Is implemented by a short-circuit brake of the adjusting motor (2).

Description

The present invention relates to an adjusting device for the rotational angular position of a camshaft relative to the crankshaft of an internal combustion engine, in particular of the type described in the superordinate concept section of patent claim 1.

BACKGROUND OF THE INVENTION In an internal combustion engine with a hydraulic or electric camshaft adjusting device, the camshaft must be in a predetermined basic position with respect to the crankshaft when starting to ensure a reliable engine start. The basic position is generally on the “lag side (retard)” for the intake camshaft and on the “early side (advance)” for the exhaust camshaft.

  During normal operation of the vehicle, the camshaft is adjusted and moved to its basic position each time when the engine is stopped and fixed or locked there. For this purpose, an electric adjustment motor is useful in the case of an electric camshaft adjustment, and in the case of a hydraulic camshaft adjustment, a locking unit is provided as a vane container, swivel vane or segment vane. A hydraulic rotary piston regulator is useful. The locking unit fixes the hydraulic adjustment device at its basic position until the hydraulic pressure is high enough to adjust the camshaft after restarting the internal combustion engine.

  However, in the case of engine stop (engine stall) of the internal combustion engine, since the adjusted adjustment of the hydraulic camshaft adjusting device is impossible, the camshaft may be in an indefinite position other than the basic position.

  In the case of a hydraulic camshaft adjusting device whose basic position is on the “lag side”, the camshaft works in the direction opposite to the camshaft rotation direction at the next start of the internal combustion engine and at the time of insufficient hydraulic pressure. Based on the axial friction moment, it is automatically adjusted to the basic position on the delay side. When the basic position is in the “early side”, the camshaft must be adjusted to the basic position on the early side against the camshaft friction moment when the hydraulic pressure is insufficient. This is often done with the help of a compensating spring. The compensating spring produces a moment that is equal to the camshaft friction moment, but in the opposite direction.

  The method for bringing the internal combustion engine to the basic position after stopping the engine, which is common in the hydraulic camshaft adjusting device, is not required in the electrically driven camshaft adjusting device. This is because the adjusting motor can adjust the camshaft to its basic position each time the internal combustion engine is stopped or started. However, in the case of an electric camshaft adjusting device, the adjusting motor and / or its control may fail, so that at least the basic position or emergency operation required for limited operation and restart is required. Achievement of the position will be prevented.

The object of the present invention is to adjust the camshaft to its emergency operating position or basic position in a simple form even when the adjusting motor or its control unit or current supply unit fails, and without requiring current. It is to provide an electrical camshaft adjustment device that can do this.

SUMMARY OF THE INVENTION The structural configuration of the adjustment transmission device defines the size of the fixed transmission device transmission ratio i ₀ and thus the camshaft adjustment device. Adjustment of the camshaft in the direction of the basic position or emergency operation position on the early or late side is performed when the adjusting transmission is rotating by simply braking the adjusting shaft when the adjusting motor or its current supply section fails. . This can be done during engine operation and when the internal combustion engine is coasting or starting. Since the basic position of the camshaft is optimally suitable for engine start and low engine speeds and is possible for higher engine speeds, it is thus possible to reach at least the maintenance station.

  The braking of the adjusting shaft can be performed by mechanical braking or eddy current braking. However, these brakes require current for their operation. In contrast, the short-circuit brake according to the present invention operates with a short-circuit current generated when the adjusting motor is dragged, and therefore the short-circuit brake is electrically self-sufficient. Since there is no mechanical friction, the short-circuit brake operates without wear.

When selecting the adjustment transmission device, it becomes a problem whether to use a negative transmission device or a positive transmission device. The negative transmission device has a fixed transmission device transmission ratio i ₀ <0, and the positive transmission device has a fixed transmission device transmission ratio i ₀ > 0. At the positive fixed transmission transmission ratio i ₀ , the drive shaft and the driven shaft have the same rotational direction with respect to the stopped adjustment shaft and the components connected to the adjustment shaft, and the negative fixed transmission transmission At the ratio i ₀ , the drive shaft and the driven shaft have opposite directions of rotation.

  In the case of a negative transmission, when the adjustment shaft is fixed and the drive shaft rotates clockwise, the driven shaft, and thus the cam shaft, rotates counterclockwise. This corresponds to the lag adjustment.

In the case of a positive transmission with a fixed transmission ratio i ₀ > 1, when the adjustment shaft is fixed and the drive shaft rotates clockwise, the driven shaft is slower than the drive shaft, ie counterclockwise, As a result, it rotates in the direction of the basic position on the “lag side”.

In the case of a positive transmission where the transmission ratio of the fixed transmission is 0 <i ₀ <1, when the adjustment shaft is fixed and the drive shaft rotates clockwise, the driven shaft is faster than the drive shaft, ie, clockwise, and thus Rotates in the direction of the “early side” basic position. These relationships can be applied to all three-axis transmissions that are symmetrical in consideration.

  Advantageously, a double eccentric transmission or a rocking transmission and another double eccentric transmission are provided as the adjustment transmission. The double eccentric transmission is superior in terms of low friction, simple structure and operation without vibration.

  According to another advantageous configuration of the invention, the double eccentric transmission has a camshaft stationary cover, which is rigidly connected to an axial pin, the pins having the same structure A spur gear engaged with the two spur gears formed in the above by line contact and driven by the adjusting motor via the double eccentric body shaft meshes with the internal gear of the crankshaft stationary.

  However, the use of a central standard clamping screw with a screw sleeve as a bearing surface for the rolling bearing part of the double eccentric body shaft requires a relatively large axial construction space. Spur gear sliding bearings formed in the same structure offer advantages in terms of cost and construction space over rolling bearings, although frictional losses are increased.

Advantageously, the number of teeth Z _NW (corresponding to the number of driven side teeth) of each of the two spur gears formed in the same structure is the number of teeth Z _KW (corresponding to the number of driving side teeth) of the internal gear mounted on the crankshaft. This leads to a fixed transmission transmission ratio 0 <i ₀ <1. This fixed transmission transmission ratio causes camshaft adjustment in the “early side” direction as is common in exhaust camshafts when a positive transmission is presented and the adjustment shaft is braked.

  In another advantageous configuration of the invention, another double eccentric transmission has a crankshaft stationary drive wheel that is rigidly coupled to an axial pin, the pin However, a spur gear formed in the same structure, which is engaged in a line contact in the hole of two spur gears formed in the same structure and can be driven via a double eccentric shaft by an adjusting motor, is a cam. Engage with a fixed shaft internal gear.

  By mounting the double eccentric body shaft on the cylindrical screw head of the central special clamping screw, an axial configuration space is obtained. Both solutions for the support of the double eccentric shaft and spur gear are suitable for the double eccentric transmission.

Advantageously, the number of teeth Z _NW (corresponding to the number of driven teeth) of the internal gear of the camshaft is larger than the number of teeth Z _KW (corresponding to the number of driving teeth) of the spur gear formed in the same structure. This leads to a fixed transmission transmission ratio i ₀ > 1.

  The three phases of the adjusting motor produce a torque course with less variation of the adjusting motor and at the same time have little construction effort. The possibility of short-circuiting one phase, two phases or all three phases allows a fine adjustment of the short-circuit brake moment.

  A short-circuit switch is provided, which is closed when the adjusting motor is de-energized and is open when the adjusting motor is energized. As soon as the adjusting motor and / or its current supply section fails, the camshaft The fail-safe function works to guide the vehicle back to its basic position or emergency operation position. This is also true in the case of the engine stop of the internal combustion engine, where the camshaft position of the internal combustion engine is corrected during the subsequent starting process.

  A clocked short circuit is also suitable to limit the heating of the regulating motor. In this case, the short-circuit switch is opened when a predetermined short-circuit current is reached, and then automatically closed. Since this process is advantageously controlled and operated by the short circuit current itself, clock control also works in the event of a failure of the voltage supply of the regulating motor or the control device. The brake current may be taken from an active device, such as an accumulator. The automatic closing is performed, for example, by a spring force.

  In order to limit the high short-circuit current, it is advantageous that a line resistance is arranged on the short-circuit line.

  Advantageously, the short-circuit line is provided with an electronic current regulator operated by a short-circuit current. This solution also works independently of the current supply of the regulating motor.

BRIEF DESCRIPTION OF THE DRAWINGS Other features of the present invention can be seen from the following description and drawings in which embodiments of the invention are schematically illustrated.
FIG. 1 is a view showing a camshaft adjusting device including an adjusting transmission device formed as a three-axis transmission device and an electric adjusting motor having a stationary stator.
FIG. 2 is a circuit diagram of a three-phase DC regulating motor having a short-circuit line and a short-circuit switch.
FIG. 3 is a view showing a double eccentric transmission device provided with an internal gear fixed to a crankshaft.
FIG. 4 is a diagram showing a double eccentric transmission device provided with an internal gear fixed on a camshaft.

DETAILED DESCRIPTION OF THE DRAWINGS FIG. 1 schematically shows a camshaft adjusting device provided with an adjusting transmission device 1 and an adjusting motor 2. The camshaft adjusting device is useful for adjusting the rotational angular position between the camshaft 3 of the internal combustion engine (not shown) and the crankshaft (not shown).

  The adjustment transmission device 1 is incapable of relative rotation with respect to a drive part 4 having a drive wheel 7 stationary relative to the crankshaft, a stationary driven part 5 stationary relative to the camshaft, and a permanent magnet rotor 8 of the adjustment motor 2 It is formed as a triaxial transmission device with an adjusting shaft 6 coupled thereto. The adjustment motor 2 has a stator 9 that is fixedly disposed on the housing 10.

  The camshaft 3 has a basic or emergency operating position that must be achieved for a reliable start and limited operation of the internal combustion engine. The achievement of the basic position or the emergency operation position can be performed without any problem even after the internal combustion engine is stopped if the adjusting motor 2 is complete. This is because the adjusting motor 2 adjusts the camshaft 3 to the basic position when the internal combustion engine is stopped or restarted. However, it should be possible to perform at least limited engine operation and restart so that at least the maintenance station can be reached if the adjusting motor 2 fails.

The adjusting transmission device 1 and its fixed transmission device transmission ratio i ₀ are such that the camshaft 3 reaches its basic position when the internal combustion engine is started only by braking the adjusting shaft 6 so that the internal combustion engine can be started. Designed to be.

When the adjusting shaft 6 is stationary and the drive part 4 rotates clockwise, the following holds for the design of i ₀ :
When i ₀ <0, a negative transmission device that performs a delay side adjustment is presented, when i ₀ <1, a positive transmission device that performs an early side adjustment is presented, and when i ₀ > 1, a positive transmission device that performs a delay side adjustment is presented. Is presented.

  FIG. 2 shows a circuit diagram of the stator 9 of the adjusting motor 2. The adjustment motor 2 is formed as a brushless DC motor and includes three phases 11 connected in a star shape. The phase 11 has a stator winding 12 and is supplied with current in phase by a control device 13 via a control line 15.

  The three phases 11 are triangularly connected by a short-circuit line 14. The short-circuit line 14 is provided with a short-circuit switch 16. The short-circuit switch 16 is closed when the adjusting motor 2 is not energized, and is opened when the adjusting motor 2 is energized. By closing the short-circuit switch 16, a short-circuit current flows, which is useful for a short-circuit brake of the regulating motor 2 acting as a generator. The closing of the short-circuit switch 16 can be implemented individually or entirely. As a result, the braking force can be adjusted.

  An excessively high short-circuit current can endanger the regulating motor 2 and thus a current limitation is necessary. Current limiting can be implemented by current dependent opening of the short-circuit switch 16. The short-circuit switch 16 is automatically closed when it falls below the limit value, for example by a spring force.

  The short-circuit current is also limited by the output resistor 17 provided in the short-circuit line 14. An electrical current regulator 18 arranged on the short-circuit line 14 and supplied with a short-circuit current serves the same purpose.

  FIGS. 3 and 4 show an adjusting transmission, which is formed as a three-axis transmission, with similar but differently arranged components.

  FIG. 3 shows a double eccentric transmission device 19 including a crankshaft stationary sprocket 21, a camshaft stationary cover 25, and an adjustment shaft formed as a double eccentric shaft 29. . The double eccentric body shaft 29 is coupled to an adjustment motor (not shown) via a detachable key shaft joint 37. As dissociable joints, wedge shaft joints, polygon shaft joints, tooth shaft joints, square shaft joints, square shaft joints and hexagon shaft joints are also possible.

  The camshaft stationary cover 25 is fastened to the camshaft rod of the camshaft 65 via the fastening sleeve 30 with the help of a central standard fastening screw 31. The opening 66 of the key shaft joint 37 allows the screw tool to approach the screw head 36 of the central standard clamping screw 31.

  The rotational angle position between the cam shaft 65 and the cam shaft stationary cover 25 is determined by the fixed pin 39. The fixing pin 39 is disposed in the aligned hole of the cover 25 and the cam shaft rod 38 by press fitting.

  The clamping sleeve 30 simultaneously serves as a bearing surface for the needle sleeve 32 of the double eccentric shaft 29. The double eccentric shaft 29 has two identical, but 180 ° offset, eccentrics 67 which are fully compensated thereby. The eccentric body 67 drives two spur gears 28 formed in the same structure via the sliding support portion 33. The spur gear 28 meshes with the internal teeth row 22 of the crankshaft-fixed internal gear 20. The internal gear 20 is formed integrally with the sprocket 21.

  The cam shaft stationary cover 25 has an axial hole 63. The pin 26 is press-fitted in the axial hole 63. The pin 26 passes through the axial hole 27 of the spur gear 28 formed in the same structure and enters the axial hole 68 of the closing cover 34. The axial holes 63 and 68 are arranged in alignment, and are located at equal intervals on one circle centered on the rotation axis 64 of the camshaft adjusting device. The axial hole 27 has a diameter larger than the pin 26 by twice the amount of eccentricity of the eccentric body 67. The pin 26 is in line contact with the inner periphery of the axial hole 27.

  The closing cover 34 serves to close the double eccentric transmission 19 and also serves to fix the double eccentric shaft 29, the spur gear 28 and the internal gear 20 in the axial direction. The closing cover 34 is fixed in the axial direction by a retainer ring 35. The retainer ring 35 is seated in the groove 78. The groove 78 is arranged at the end of the pin 26 protruding from the axial hole 68 of the closure cover 34. The location of the groove 78 defines the spacing between the inner surface 79 of the cover 25 and the inner surface 80 of the closure cover 34. In so doing, the axial play required for the relative movement for the corresponding sliding surfaces of the double eccentric shaft 29, spur gear 28 and internal gear 20 is taken into account.

  The internal gear 20 is supported on the cover 25 by a sliding support portion 43. In particular, the sliding bearing 43 receives the force of the sprocket 21. The sprocket 21 is formed integrally with the internal gear 20 and is coupled to the crankshaft of the internal combustion engine through a chain so as not to be relatively rotatable. The sprocket 21 is driven by the crankshaft at half the number of revolutions of the crankshaft. The driving moment of the sprocket 21 is transmitted to the cover 25 and the cam shaft 65 via the spur gear 28 and the pin 26. The number of pins 26 is adjusted according to the height of the driving moment.

  In this example, since the rotational speed of the double eccentric body shaft 29 is smaller than the rotational speed of the sprocket 21 due to, for example, a short-circuit brake of the adjusting motor, the rotational speed is lower than the rotational speed of the cam shaft 65. The shaft 65 is adjusted in the “early side” direction.

  FIG. 4 shows another double eccentric transmission device 44. This double eccentric transmission device 44 has a crankshaft stationary sprocket 46, a camshaft stationary internal gear 51, and an adjustment shaft formed as a double eccentric body shaft 50. The adjusting shaft is coupled to an adjusting motor (not shown) via a detachable wedge shaft joint 62. The double eccentric transmission device 44 is fastened to the cam shaft rod 55 of the cam shaft 69 by a central special tightening screw 54. Also in this case, the rotational angle position between the cam shaft 69 and the double eccentric transmission device 44 is determined by the fixing pin 60. The fixing pin 60 is seated in the aligned holes of the internal gear 51 and the camshaft rod 55 by press fitting. The central special tightening screw 54 can be tightened through the wedge shaft joint 62.

  The cylindrical screw head 53 of the special clamping screw 54 simultaneously serves as a bearing surface for the needle sleeve 57 of the double eccentric shaft 50. Thereby, the double eccentric body axis | shaft 50 is comprised extremely short. The double eccentric shaft 50 also has two identical eccentrics 70 offset by 180 °. The eccentric body 70 drives two spur gears 49 formed in the same structure via the rolling support portion 56. The rolling bearing 56 may be replaced with a sliding bearing. Sliding bearings save cost and construction space, but have higher friction in return. The spur gear 49 meshes with the internal teeth row 52 of the cam gear fixed internal gear 51. A crankshaft drive wheel 45 is disposed around the internal gear 51, and the drive wheel 45 has a peripheral surface portion 75 formed integrally with the sprocket 46 and the side surface portion 76. The side part 76 serves inter alia for the side closure of the double eccentric transmission 44. The peripheral surface portion 75 is supported on the peripheral surface of the internal gear 51 by a sliding support portion 58. The side surface portion 76 has an axial hole 77 in which an axial pin 47 is press-fitted. As in FIG. 3, the pin 47 engages in the hole 48 of the spur gear 49 and transmits the driving moment of the driving wheel 45 to the internal gear 51 and the cam shaft 69 via the spur gear 49. The crankshaft-driven drive wheel 45 is fixed in the axial direction by a snap ring 59, whereby the spur gear 49 and the double eccentric body shaft 50 are also fixed in the axial direction. The snap ring 59 is seated in the radial groove 71 of the drive wheel 45 stationary on the crankshaft, and is abutted against the end surface 72 of the internal gear 51 on the camshaft side by a flank. The end surface 73 of the internal gear 45 opposite to the cam shaft is provided with play and is abutted against the inner surface 74 of the drive wheel 45 in the axial direction. This play allows relative movement of the internal gear 51, the drive wheel 45, the spur gear 49 and the double eccentric shaft 50.

  As in the case of the double eccentric transmission device 19, the lubrication of the double eccentric transmission device 44 is carried out through the inflow hole 61 to the needle sleeve 57 and from there to other components by centrifugal force.

  In this case, since the rotational speed of the double eccentric body shaft is smaller than the rotational speed of the sprocket 46 due to, for example, a short circuit brake of the adjusting motor, the camshaft 69 rotates more slowly than the sprocket 46, thereby To be adjusted.

  The double eccentric transmission 19 serves as an adjusting cam for the exhaust camshaft having a basic position on the “early side”, and another double eccentric transmission 44 has an intake cam having a basic position on the “lagging side”. Serves as a shaft adjustment transmission.

It is a figure which shows the camshaft adjustment apparatus provided with the adjustment transmission apparatus formed as a 3-axis transmission apparatus, and the electric adjustment motor which has a stator of a housing stationary.

FIG. 3 is a circuit diagram of a three-phase direct current adjustment motor including a short-circuit line and a short-circuit switch.

It is a figure which shows the double eccentric transmission apparatus provided with the internal gear of a crankshaft stationary.

It is a figure which shows the double eccentric transmission apparatus provided with the internal gear of a cam shaft stationary.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Adjustment transmission device, 2 Adjustment motor, 3 Cam shaft, 4 Drive part, 5 Driven part, 6 Adjustment shaft, 7 Drive vehicle, 8 Permanent magnet rotor, 9 Stator, 10 Housing, 11 phase, 12 Stator winding, 13 Control Device, 14 short circuit line, 15 control line, 16 short circuit switch, 17 output resistance, 18 electronic current regulator, 19 double eccentric transmission device, 20 crankshaft stationary internal gear, 21 sprocket, 22 internal tooth row, 23 Outflow hole, 24 Outflow hole, 25 Cam shaft stationary cover, 26 Pin, 27 Axial hole, 28 Spur gear, 29 Double eccentric shaft, 30 Tightening sleeve, 31 Standard tightening screw, 32 Needle sleeve, 33 Sliding Bearing, 34 Closure cover, 35 Retainer ring, 36 Standard screw head, 3 7 Key shaft coupling, 38 Cam shaft rod, 39 Fixing pin, 40 Inflow conduit, 41 Lubricating oil hole, 42 Outflow hole, 43 Sliding bearing, 44 Another double eccentric transmission device, 45 Crank shaft stationary drive vehicle , 46 sprocket, 47 axial pin, 48 hole, 49 spur gear, 50 double eccentric shaft, 51 cam shaft fixed internal gear, 52 internal tooth row, 53 cylindrical screw head, 54 special tightening screw, 55 Cam shaft rod, 56 Rolling bearing, 57 Needle sleeve, 58 Sliding bearing, 59 Retainer ring, 60 Fixing pin, 61 Inlet hole, 62 Wedge shaft joint, 63 Axial hole, 64 Rotating axis, 65 Cam shaft, 66 Opening, 67 Eccentric body, 68 Axial hole, 69 Cam shaft, 70 Eccentric body, 71 Radial groove, 72 Cam shaft side End surface, 73 end surface opposite to the camshaft, 74 axial inner surface, 75 peripheral surface portion, 76 side surface portion, 77 axial hole, 78 groove, 79 inner surface, 80 inner surface

Claims (15)

An electrical adjustment device for the rotational angular position of the camshaft (3, 65, 69) relative to the crankshaft of the internal combustion engine, provided with an adjustment transmission device (1), the adjustment transmission device (1 ) Is formed as a triaxial transmission device and is coupled to the crankshaft stationary drive portion (4), the camshaft stationary driven portion (5), and the electric adjustment motor (2) so as not to rotate relative to each other. An adjusting shaft (6), the adjusting motor (2) has a permanent magnet rotor (7) and a stationary stator (8), and a driving part (4) and a driven part. Fixed transmission transmission ratio presented when the adjustment shaft (6) is stationary with (5)

The size of the adjustment transmission device (1) is the type of the positive transmission device or the negative transmission device, and the adjustment direction of the camshaft (3, 65, 69) to the basic position located on the early or delayed side The following fixed transmission transmission ratio i ₀ can be realized on the basis of an appropriate structural configuration of the adjusting transmission (1), and the fixed transmission With the device transmission ratio i ₀ , the basic positions of the camshaft (3, 65, 69) on the early and late sides can be achieved when the adjusting transmission (1) is rotated by simply braking the adjusting shaft (6). Camshaft adjusting device with electrical drive, characterized in that the braking of the adjusting shaft (6) is preferably carried out by a short-circuit brake of the adjusting motor (2). With a fixed transmission transmission ratio 0 <i ₀ <1, a positive transmission for camshaft adjustment in the “early side” direction can be realized, and with a fixed transmission transmission ratio i ₀ > 1, a “lagging side” 2. The adjusting device according to claim 1, wherein a positive transmission for camshaft adjustment in direction is feasible.   3. The adjusting device according to claim 2, wherein a double eccentric transmission device (19) or a swing transmission device and another double eccentric transmission device (44) are provided as the adjustment transmission device (1).   The double eccentric transmission (19) has a camshaft stationary cover (25), which is firmly coupled to the axial pin (26). ) Engages in the hole (27) of two identically formed spur gears (28) by line contact and can be driven by the adjusting motor (2) via the double eccentric shaft (29) 4. The adjusting device according to claim 3, wherein the spur gear (28) meshes with an internal gear (20) fixed on the crankshaft.   A double eccentric shaft (29) is supported by a needle sleeve (32) on a screw sleeve (30) of a central standard fastening screw (31) and is spur gear (28) formed in the same structure. The adjusting device according to claim 4, wherein the sliding shaft is supported on the double eccentric body shaft. The number of teeth Z _NW (corresponding to the number of driven side teeth) of each of the two spur gears (28) formed in the same structure is the number of teeth Z _KW (the number of driving side teeth) of the internal gear (20) fixed on the crankshaft. 6. The adjustment device according to claim 5, wherein the adjustment device is smaller than the equivalent), and this leads to a fixed transmission transmission ratio 0 <i ₀ <1.   Another double eccentric transmission (44) has a crankshaft stationary drive wheel (45) that is rigidly coupled to the axial pin (47); The pin (47) engages in the hole (48) of two spur gears (49) formed in the same structure by line contact, and the double eccentric shaft (50) is moved by the adjusting motor (2). 4. The adjusting device according to claim 3, wherein a spur gear (49) formed in the same structure, which can be driven via the gear, meshes with an internal gear (51) fixed on the camshaft.   A double eccentric body shaft (50) is supported by a cylindrical screw head (53) of a central special tightening screw (54), and a spur gear (49) formed in the same structure is double eccentric. 8. The adjusting device according to claim 7, wherein the adjusting device is supported on the body axis (50) by means of a rolling bearing (56). The number of driven side teeth Z _NW of the cam shaft stationary internal gear (51) is larger than the number of drive side teeth Z _{KW of} the spur gear (49) formed in the same structure, which is a fixed transmission. 9. The adjusting device according to claim 8, which leads to a device transmission ratio i ₀ > 1.   The stator (8) of the adjusting motor (2) preferably has three phases (10), which are individually or entirely for short-circuit braking of the adjusting motor (2). 2. The adjusting device according to claim 1, wherein the adjusting device can be short-circuited.   11. The short-circuit switch (15) is provided, the short-circuit switch (15) being closed when the adjusting motor (2) is not energized and being opened when the adjusting motor (2) is energized. Adjusting device.   12. The adjusting device according to claim 11, wherein means are provided for limiting the short-circuit current.   13. The adjusting device as claimed in claim 12, wherein the short-circuit switch (15) opens when the short-circuit current limit is exceeded, preferably with the aid of a short-circuit current and automatically closes when the limit value is below.   13. The adjusting device according to claim 12, wherein a line resistance (16) is arranged on the short-circuit line (13).   13. The adjusting device according to claim 12, wherein the short-circuit line (13) is provided with an electronic current regulator (17) operated by a short-circuit current.

Images