DE102005054269B3 - Device for changing the relative angular position of a camshaft relative to a crankshaft of an internal combustion engine - Google Patents

Abstract

The invention relates to a device for changing the relative angular position of a camshaft (2) with respect to a crankshaft of an internal combustion engine, with a drive element (1) rotatably mounted with respect to the camshaft (2) and indirectly driven by the crankshaft for driving the camshaft (2) Non-rotatably connected to the camshaft (2) multi-part output element (8) and with means for producing and releasing a positive connection for torque transmission between the drive element (1) and the output element (8), via which the relative angular position between the camshaft (2) and the crankshaft can be specifically changed by relative rotation of the output element (8) relative to the drive element (1), the means for establishing and releasing the positive connection comprising at least one engagement section (30) formed on the drive element (1) and the multi-part output element (8 ) a carrier body (6 ) and at least one driver (8a, 8b), which is movable relative to the carrier body (6) and can be brought into engagement with the engagement section (30). In order to make such a device structurally simple and to ensure safe actuation of the device without the need to measure the course of the circumferential force on the drive element, it is proposed that at least one switchable mechanical actuation mechanism (10, 12, 11a) is provided, which in .. ,

Description

The The invention relates to a device for varying the relative angular position a camshaft opposite a crankshaft of an internal combustion engine with the features of the preamble of claim 1.

From the DE 197 55 495 A1 a locking device for a device for changing the timing of gas exchange valves of an internal combustion engine is known, which is arranged in the region of the cylinder head of the internal combustion engine to an intake or exhaust camshaft and from a via a traction means with a crankshaft of the internal combustion engine in driving connection crank-resistant component and from a rotatably connected to the camshaft camshaft-fixed component. Between the two components at least two pressure chambers connected to a pressure medium source are provided, and there is also a hydraulically actuable actuator arranged. About this actuator is a power transmission connection from the crankshaft fixed component to the camshaft-fixed component. By the actuator both components within a control range against each other are rotated and fixed, so thus a relative rotation and / or a continuous hydraulic clamping of the camshaft relative to the crankshaft is effected. The camshaft-fixed component is arranged so that it penetrates the crankshaft-fixed component axially. Furthermore, the camshaft-fixed component at its free end outside the device a pressure medium-tight with one or more pressure chambers of the device hydraulically connected and an axial guide axially movable locking element, with which falls below a for adjusting the control element of the device necessary pressure of the hydraulic pressure medium by a Power supply independent of the control element torsion-proof power transmission connection between the crankshaft fixed component and the camshaft-fixed component in one or more rotational positions of these is produced to each other. A disadvantage of this known locking device is that the actuation of the actuating element takes place hydraulically, so that hydraulic connections and corresponding pressure generating means for actuating the actuating element are required. Furthermore, this known construction of the locking device is structurally complex.

Also from the US 5,228,417 a camshaft adjusting device is known in which also a hydraulic actuator with corresponding pressure generating means is required. This known device is structurally complex.

A device according to the preamble of claim 1 is known from DE 42 29 202 A1 known. This known device is comparatively complicated, because there in the output element (inner element 6 ) Hydraulic cylinders are arranged therein with longitudinally displaceable, one-sided pressurizable piston, wherein the pistons are arranged on a chordal course to the annular Nockenwellenrad. Furthermore, on the camshaft gear driving elements are provided, which, starting from the inner circumference of the camshaft wheel radially inwardly in recesses of the output element (inner element 6 protrude). The driver elements have curved support surfaces on which the pressure chambers opposite end faces of the pistons are guided. In this way, when the pistons are acted upon by hydraulic pressure, a positive connection is formed between the support surfaces of the driver elements and the end faces of the pistons facing them.

In particular, the inner element 6 , which corresponds to the output element according to the preamble of claim 1, is elaborately formed in the known device. On the one hand, a plurality of hydraulic bores and hydraulic cylinders are provided within the inner element, so that an effective in both directions positive connection between the drive element and the driven element can be produced. On the other hand, an electrically actuated switching valve is provided to ensure an actuation of the device at the right time, which can be designed in particular as a proportional valve, which meets the requirements for effective camshaft adjustment at high rated speeds of the internal combustion engine, the rapid response of the hydraulic freewheel on which require alternating force directions of the circumferential force. To ensure proper functioning of the known device, even at high rated speeds, are in the from the DE 42 29 202 A1 Known device provided force sensors in the region of the bores of the piston bore units whose signals are transmitted to a measured value preparation. The actuator of the switching valve takes place via an actuator downstream of the measured value processing.

Of the Invention is based on the object, a device according to the preamble of claim 1 such that the entire device overall design is simpler. In particular, should the device will operate safely without the need for force sensors with which the force curve of acting on the drive element Peripheral force is measured.

These The object is achieved in the invention in that at least one switchable mechanical actuating mechanism is provided, the at least one, designed as a driver Includes positive-locking element and in at least two from each other different angular ranges of the camshaft rotation can be added and by which the at least one driver with the at least an engaging portion against a restoring force disengaged can be brought, wherein the actuating mechanism one on the at least one driver in the direction of engaging portion acting force storage and between an actuator and the driver effective, the guided movement of the driver controlling cam joint comprises.

The Invention is based on the recognition that on the camshaft an internal combustion engine in operation on an average fluctuating torque with positive and negative values of the torque acts. The torque to be transmitted from the drive element to the camshaft changes into fast sequence its direction or its sign. Continue used the fact that there are certain angular ranges of camshaft rotation where are independent from the speed exclusively positive torques abut the camshaft, while in other specific angular ranges of camshaft rotation are exclusively negative Torques abut the camshaft. In the event that the positive connection between the drive element and output element is released and the relative change the angular position between the drive element and the output element allows is, is due to the applied positive torque, the angular position in a first adjustment direction and by the adjacent negative Change torque in a second adjustment. Will the switchable operating mechanism the device according to the invention with an actuator, that in a corresponding angular range of camshaft rotation is arranged, switched on, there is a release of the positive connection between the drive element and output element and there is a Adjustment in the, the direction of the torque in the corresponding Angle range of the camshaft rotation associated direction. On this way is exclusive the angular position with which the actuating element engages in the device, the adjustment. In this way can the relative angular position of the camshaft relative to the crankshaft changed in both directions be without affecting the course of the camshaft or the drive element acting circumferential force by means of force sensors are measured got to.

ever according to the desired Adjustment direction (forward or backward) is the inventively provided releasable driver connection solved in a phase negative or positive torque. On This way, an adjustment, ie a rotation of the camshaft across from the drive element generated.

By Use a spring between the camshaft and the drive wheel is arranged these angular ranges are favorably influenced. Especially can the angular range of the forward rotating torque can be increased.

at The invention is the direction of rotation, in which the output element across from the drive element is relatively rotated, determined exclusively by that the at least one switchable mechanical actuating mechanism switched on either in an angular range of the camshaft rotation in which one is exclusively positive or exclusive Negative torque acts on the camshaft. A separate Determination of the respective at the time of actuation on the camshaft or on the drive element acting circumferential force is not required.

The fact that in the inventive device, the at least one driver with the at least one engaging portion of the drive element against a restoring force disengaged, it is ensured that the driver in a position in which he is not engaged with the engaging portion, always a Restoring force acts, by which the driver can be brought back into engagement with the engagement portion. It is therefore not necessary to generate each time an actuating force of the driver causing, as in the hydraulic solution according to DE 42 20 202 A1 is required, where for the actuation of the piston, a hydraulic pressure must be established.

Experiments have shown that it is almost impossible, the disengaged driver connection in terms of a clutch (as in the DE 42 20 202 A1 ) engage again exactly when the desired adjustment angle is reached. In addition, only a limited adjustment angle can be achieved with such a clutch operation.

An essential part of the inventive concept is therefore to form-fit the switchable, detachable driver connection. In order to optimize the switching process, it is additionally provided according to the invention to provide more than one detachable, positive driver connection. These releasable form-locking driver connections alternately generate by latching the positive connection between the drive element and the output element and thus also with the camshaft. A part of the dog connections (at least one) is engaged and transmits the torque, while another part of the dog connections (at least one) is in a latched intermediate position or waiting position and transmits no torque.

One Another essential part of the inventive concept and an important Advantage of the device according to the invention is that work to solve the positive fit, so to retreat a Driver, the rotational movement of the camshaft or rotary motion of the drive element is removed in a purely mechanical way. For this is a switchable according to the invention actuator provided, the cylinder head fixed angular position relative to the angular position the camshaft by the position of the positive and the negative torque angle section is determined.

Farther it is according to the invention for optimization the switching process provided that each of the positive locking generating Driver (at least one driver must be provided) in the Positive locking generating direction is acted upon by a restoring force. The restoring force becomes advantageous caused by a spring. However, it is just as possible that the restoring force is caused solely by the centrifugal force acting on the elements of the actuating mechanism, i.e. on the at least one driver, acts by the rotation of the device.

According to the invention the actuating mechanism Therefore, an energy storage, through which a force in the direction on the engaging portion of the drive element on the at least exercised a driver becomes. Furthermore, one is the led Movement of the driver controlling cam joint provided which between an actuator and the taker is effective. If the actuating element is switched on, so it occurs with the driver under the effect of the curve joint interacting so that the cam joint in conjunction with the Rotation of the camshaft or the output element a guided movement of the driver caused by the driver disengaged is brought with the engagement portion.

Around that the guided To form movement of the driver controlling cam joint points the at least one driver has a ramp with a control curve, which due to the rotation of the driver with the actuator cooperates when the actuator is switched on. The actuator can be designed as a switchable pin, which is independent of the camshaft rotation in the rotation path, i. into orbit can be introduced (switched on) of the driver, so that the Pin represents an obstacle on which the driver with his control cam due to its rotation. In this case, the actuating element acts with the control cam of the driver in the sense of a curved joint together, so that transferred to the driver movement who is the driver except Engages the engagement portion of the drive element brings. Basically it would be too possible, the control cam not on the driver, but on the actuator train. It just depends on having a curve joint becomes effective, which is the driver disengaging movement controls. The positioning of the actuator, i. the Insertion of the actuating element into the orbit of the driver can e.g. electrically or hydraulically respectively.

alternative to a mechanical actuator, which is switched into the orbit of the driver to with this over a cam joint cooperates, the actuator can also on the driver acting solenoid or hydraulic cylinder include. If an electromagnet is provided, then in the two different angular ranges of the camshaft rotation e.g. Sliding contacts or similar Contacts arranged over which is the electromagnet activated. Is a hydraulic cylinder provided so are in the two different angular ranges the camshaft rotation e.g. by the camshaft rotation activatable valves provided by which the action of the hydraulic cylinder can be switched is. In these alternative embodiments of the actuator is, however, deviating from the above solution, the Work to solve the form fit, so to retreat a driver, not the rotational movement of the camshaft or the Rotary movement of the drive element taken by mechanical means, but it is required electrical energy or hydraulic pressure to disposal to ask to solve to effect the positive connection.

Advantageous the drive element has at least two engagement sections, which are spaced apart in the circumferential direction. Is only one driver provided, so this is designed so that he with the two Engagement portions is alternately engageable. This can e.g. be achieved by a between two engagement positions switchable driver is provided, which in the one Engagement position with the one engagement portion and in the other Engagement position with the other engagement portion is engaged.

In another embodiment of the invention, the multi-piece output member on two drivers, each of which has a Eingriffsab sections is assigned. Each driver is alternately engageable with the respective engagement portions. "Alternating" in this context means that at any one time only one driver with its associated engagement portion is engaged, while the other driver is out of engagement and under the action of engaging in the direction of restoring portion is in a standby position from which he can engage in a recess of the engagement portion and can thus establish a positive connection when the cam shaft is rotated relative to the drive element.

Basically the engagement portion of the drive element as a separate component be formed, which firmly connected to the drive element is. cost-effective let yourself However, the engaging portion realize in that he as Teeth and gullets having teeth section integrated into the drive element is.

Especially It is advantageous if two engagement sections on the drive element are formed as teeth and tooth gaps having exhibiting first and second toothing sections are formed. In this case supports itself the currently not engaged driver on a tooth of its associated engagement portion against the Force of an energy storage in a waiting position. Find now a relative rotation of the output element relative to the Drive element instead, so the support of the driver goes on the Tooth of his assigned engagement section lost and the force of e.g. designed as a spring element of energy storage presses the Driver in the radial direction in an engaged position with him associated engagement portion. In this way it is achieved that no separate operating force for operation of the driver must be applied. The operating force is due to the Force accumulator in the waiting position of the driver already on the Driver, so that it is brought into the engaged position, as soon as the support on the tooth of the engaging portion is omitted.

at this particularly advantageous embodiment of the invention So provided in a in the range of the drive element on the Camshaft rotatably mounted and provided with guides carrier body two To lead takers so that they for the purpose of torque transmission can engage in corresponding recesses on the drive element, that the locking is supported by spring force, but alternately in each case only one of the drivers a recess for locking finds when the cam shaft is rotated relative to the drive element. Now the connection is solved, by withdrawing the engaged carrier, one enters Twist by a fixed angle, namely until the other one Driver finds a recess for snapping. This in turn can subsequently in turn withdrawn from the recess and the positive connection thus solved again so that is another angular step of the adjustment movement he follows. This way you can do anything size Adjustment angle realized in fast, controlled steps become.

It be explicit at this point mentioned that the drivers can also be performed on the drive element and in corresponding wells the camshaft or on a non-rotatably connected to the camshaft Engage component.

is the guided at least one driver relative to the carrier body, so the relative movement the driver opposite the carrier body either by a rotational movement or by a translational movement or but done by a combined rotation and translation. In a simple way a relative movement of the driver relative to the support body realized by that on the carrier guides are formed, through which the driver is guided relative to the carrier body. These guides can For example, formed as parallel aligned projections be a linear guide for the Make taker. In this case, the driver leads a pure Translational movement (displacement movement) off.

deviant From the embodiment described above, the leadership of the Driver opposite however, the carrier body also by any other guidance device be achieved. The management device does not need to be connected to the carrier body be. Another conceivable guide the driver opposite the carrier body could, for example by a rotatable mounting of the driver on a fixed to the carrier body connected axis of rotation can be achieved.

are two drivers provided, each one assigned to them Engagement section are assigned, it is advantageous if a force accumulator acting on the two drivers in two directions is provided by the two drivers each in the direction on their associated engagement sections with a restoring force can be acted upon. In this way, with only one energy storage, formed, for example, as acting in two directions spring is, the application of the required restoring force to the driver be ensured.

The inventive device is independent of whether the camshaft on a chain wheel, which is driven by the crankshaft via a drive chain, via a toothed belt wheel, which is driven by the crankshaft via a toothed belt or driven by a gear which is driven by the crankshaft via a gear transmission. In each of these drive elements (sprocket, timing belt, gear), the at least one engagement portion according to the invention can be integrated, so that the device according to the invention can interact with each of these drive elements.

Of the Invention is also Based on the object, a method for changing the relative angular position a camshaft opposite To provide a crankshaft of an internal combustion engine, which at any time a targeted change in the angular position allows without that at the time of actuation the adjusting device on the camshaft or on the drive element adjacent circumferential force must be determined.

According to the invention this Task by a method having the features of the claim 16 solved.

According to the invention is a with at least one engagement portion of the drive element in Engageable, detachable Carrier connection for specific adjustment of the relative angular position the camshaft opposite the crankshaft provided at the direction of adjustment is determined in which part of the orbital motion of the Camshaft of positive locking Engagement of the driver is dissolved in the engaging portion. The solution is done of the positive Engage in a portion of the orbital motion of the camshaft, in which on the camshaft as a first defined positive torque is applied, the relative rotation of the output element takes place across from the drive element in a first direction of rotation. Will against it the detachable Carrier connection in a second section of the orbital motion the camshaft released from its engagement, in which on the camshaft a negative, the first torque counteracting second torque is applied, the relative rotation of the output element takes place across from the drive element in a second direction of rotation, the first Direction of rotation is opposite.

In a preferred embodiment the method according to the invention is an adjustment desired Length in divided into successive sub-steps of discrete length. For this purpose, the engaging portions are as teeth and tooth spaces having Formed toothing sections and the detachable driver connection comprises at least two movable relative to the toothed sections driver, each having at least one engagement element, wherein the Engagement elements alternately in the tooth gaps of Gearing sections are brought into positive engagement, and wherein the respective non-engaged engagement elements through the respective teeth their assigned toothed section against the force of a Force accumulator (e.g., a spring) held in a waiting position become. In this way, the output element against the Drive element in each case incrementally further rotated by one tooth, so that the entire adjustment movement through several consecutive Part adjustments is effected.

In In a particular embodiment of the invention, the teeth on the entire circumference arranged.

in the The invention is based on an embodiment drawing closer explained. Show it

1 an exploded view of the device according to the invention

2 the drive element in side view

3 the drive element in perspective view

4 the device according to the invention in a first operating state

5 the device according to the invention in a opposite 4 other operating state (decoupled)

6 the device according to the invention in a relation to the 4 and 5 other operating state

7 the carrier body in top view and in side view and in perspective view

8th a driver of the device according to the invention in a perspective view.

In 1 the device according to the invention is shown in an exploded view. The individual components of the device according to the invention can be seen in detail, namely the drive element 1 , the multipart, the carrier body 6 as well as the drivers 8a . 8b comprehensive output element 8th as well as the spring 10 for applying a restoring force to the driver 8a . 8b , by the driver in the assembled state 8a . 8b be spread radially outward. The adjusting device is suitably replaced by a in 1 unspecified hexagon socket screw with the camshaft 2 rotatably connected. Between the camshaft 2 and the drive element 1 is one in 1 unspecified mounting bushing arranged in the direction of a drive element 1 having extending journal, on which the drive element 1 opposite the camshaft 2 is mounted relatively rotatable.

In 2 is the driving element 1 , which is formed in the present embodiment as a sprocket, shown in side view. Evident is the external toothing, in which engages the driven by the crankshaft drive chain. The drive element 1 has circumferentially extending openings 3a . 3b on. At the outer peripheries of the breakthroughs 3a . 3b are engaging sections 30a . 30b arranged as gearing sections 30a . 30b formed and integral with the drive element 1 are connected. The engagement sections / gearing sections 30a . 30b have teeth 4a . 4b and tooth gaps 5a . 5b on. About the driver sections / gearing sections 30a . 30b For example, the drive element can be positively coupled to an output element rotatably connected to the camshaft so that the drive element can drive the camshaft via this positive connection. To a relative rotation of the output element relative to the drive element 1 to reach, the positive connection between the output element and the drive element 1 in the area of the engaging sections 30a . 30b be solved.

In 3 is for better understanding the drive element 1 shown in perspective.

4 shows the device according to the invention in the assembled state in a first operating position. In this operating position is the driver element 8a in an engaged position with one of the tooth spaces 5a the engaging portion 30a , About this positive connection can torque from the drive element 1 on the driver 8a and from this about the guides 7a on the carrier body 6 be transmitted, the rotation with the camshaft 2 connected is.

The drivers 8a . 8b be over the spring 10 spread radially outwards, the spring 10 on one in 4 unspecified axis is arranged, fixed to the drive element 1 connected is.

It is good to realize that the driver 8b himself with his intervention element 9b on one of the teeth 4b the engaging portion 30b supported in the radial direction. The spring force of the spring 10 keeps the driver 8b in constant contact with the face of the tooth 4b , In the 4 shown position of the driver 8b may be referred to as a waiting position or standby position, in the spring 10 a radially outward restoring force is exerted. Will now be the driver 8a by the action of the pen 12 , which is arranged outside of the device according to the invention, on the control cam 11a of the driver 8a against the restoring force of the spring 10 disengaged, so takes place due to the voltage applied to the output element torque relative rotation of the output element relative to the drive element 1 , In 4 is indicated on the right side with an arrow the positive torque direction, by which the output element relative to the drive element 1 is rotated clockwise. In the in 4 shown operating state is the pen 12 in time immediately before the engagement with the control cam 11a of the driver 8a ,

In 5 the operating state is shown, in which both drivers 8a . 8b are out of engagement. The control curve 11a of the driver 8a is with its entire length on the outer contour of the pin 12 slid along and is now in the last point of engagement with the pin 12 , Through the interaction of the pen 12 with the control curve 11a of the driver 8a this is against the restoring force of the spring 10 out of engagement with the engaging portion 30a has been brought. Both drivers 8a . 8b are therefore in 5 disengaged, so that the output element 6 or the camshaft 2 opposite the drive element 1 is relatively rotatable.

In the 4 . 5 and 6 is the adjustment of the angular position of the output element 8th and the associated camshaft 2 opposite the drive element 1 clockwise, indicated by the arrow. The pin not rotating with the camshaft 12 brings through contact with the cam 11a the engagement element 9a , here a tooth, with the tooth gap 5a disengaged so that the clockwise moment of the camshaft 2 the output element 8th clockwise rotation of the drive element 1 precedes until the engagement element 9b in the tooth gap 5b through the spring 10 is pressed. At the same time, turning the entire device clockwise causes the pin to rotate 12 out of contact with the control cam 11a brought.

In terms of 5 It should be noted that here is an example of a change in the angular position between the camshaft 2 and the crankshaft is shown in a first direction. The adjustment is therefore in this first direction, because the pin 12 is arranged in an angular range of the camshaft rotation, in which a positive torque is applied to the camshaft. In the same way, the adjustment could also be in the opposite direction set direction of rotation when the pin 12 in an angular range of the camshaft revolution with the control cam 11a of the driver 8a in which an exclusively negative torque on the camshaft would be engaged 2 is applied. In the invention, the adjustment is exclusively dependent on what angle range of the camshaft rotation of the pin 12 in engagement with the control cam 11a of the driver 8a occurs.

In 6 now the operating state is shown in which the driver 8b in engagement with the engagement portion 30b located. Due to the restoring force of the spring 10 is the driver 8b with its engaging element 9b in a tooth gap 5b of the engaging portion 30b engaged. The resulting positive Ver bond between the output element 8th and the drive element 1 represents the torque transmission from the drive element 1 on the camshaft 2 about the driver 8b , the guides 7b and with the camshaft 2 rotatably connected carrier body 6 for sure.

While the driver 8b now in engagement position with the engagement portion 30b is located, is the driver 8a in a waiting position, the waiting position of the driver 8b in 4 equivalent. On the driver 8a the restoring force of the spring acts 10 radially outward towards the engagement portion 30a , With its engagement element 9a the driver is supported 8a on a face of a tooth 4a of the engaging portion 30a from. The pencil 12 is completely out of engagement with the control cam 11a of the driver 8a ,

If now an in 6 not shown second pin 12 with the control curve 11b of the driver 8b would contact and so on due to the rotation of the driver 8b and the action on the control curve 11b the engagement element 9b of the driver 8b out of engagement with the engaging portion 30b would bring an operating state would again analogous to the representation in accordance with 5 be set. Both drivers 8a . 8b would again be disengaged and the drive member could in turn be rotated relative to the output member until the engagement member 9a of the driver 8a in re-positive engagement with a tooth gap 5a of the engaging portion 30a occurs.

In this way, the device according to the invention an adjustment of greater or any length can be achieved by a plurality of successive Teilverstellbewegungen. For every Teilverstellbewegung must the pin 12 with a control curve 11a . 11b of the currently engaged driver 8a . 8b to be brought.

For a better understanding of the invention is in 7 the carrier body 6 with one piece with this associated guides 7a . 7b to guide the in 7 not shown takeaway 8a . 8b shown in different views. In 7 above is a view of the carrier body 6 shown from above (top view). In the space between the successive in this illustration guides 7a . 7b are in the assembled state the in 7 not shown drivers 8a . 8b arranged. The guides 7a . 7b lead the drivers 8a . 8b in the sense of a linear guide, so that the drivers 8a . 8b relative to the carrier body 6 perform a guided shift movement.

In 7 right is a side view of the carrier body 6 shown. Here are the radially opposing guides 7a . 7b clearly visible. Finally, in 7 below a perspective view of the carrier body 6 shown from the the spatial arrangement of the guides 7a . 7b becomes clear to each other.

In 8th is a driver 8a . 8b shown, which is an engagement element 9a . 9b and a control curve 11a . 11b having. The area of the driver 8a . 8b that the curb 11a . 11b is in the axial direction offset from the engagement element 9a . 9b arranged. In the in the 1 to 7 illustrated embodiment are each two of these drivers 8a . 8b intended. The engaging elements 9a . 9b are formed here as a tooth, in the respective tooth gaps of the engaging portions 30a . 30b can engage and so a positive connection between the drive element 1 and the output element 8th manufactures. The control curve 11a . 11b of the driver 8a . 8b is designed so that when the driver 8a . 8b comes into contact with a switchable pin, the driver 8a . 8b is brought out of engagement with the associated engagement portion, so that a relative rotation of the drive element relative to the output element as described above is possible.

Due to the friction in the camshaft bearings and between the cams and the cam driven output members that actuate the valves of the engine, the angular ranges in which the camshaft have 2 a positive torque acts, a different magnitude or circumferential extent than the angular ranges, in which a negative torque on the camshaft 2 acts. By a spring 13 , which is formed for example as a spiral spring or leg spring, this can be compensated or even reinforced in a desired direction. The feather 13 is suitably designed and arranged so that it imparts a desired predefined torque to the adjustment and thereby supports the adjustment. The feather 13 is to be interpreted in such a way that it counteracts the friction torque of the camshaft and this compensated as best possible.

1

driving element

2

camshaft

3a, 3b

breakthroughs

4a, 4b

teeth

5a, 5b

gullets

6

support body

7a, 7b

Guide; projections

8th

output element

8a, 8b

takeaway

9a 9b

engaging member

10

feather

11a

cam

11b

cam

12

Actuator; pen

13

spiral spring

30a, 30b

Engaging portion; toothed section

Claims (16)

Device for changing the relative angular position of a camshaft ( 2 ) with respect to a crankshaft of an internal combustion engine, with respect to the camshaft ( 2 ) rotatably mounted, indirectly driven by the crankshaft drive element ( 1 ) for driving the camshaft ( 2 ), a non-rotatable with the camshaft ( 2 ) connected multi-part output element ( 8th ) and with means for producing and releasing a positive connection for torque transmission between the drive element ( 1 ) and the output element ( 8th ), via which the relative angular position between the camshaft ( 2 ) and the crankshaft by relative rotation of the output element ( 8th ) relative to the drive element ( 1 ) is selectively changeable, wherein the means for producing and releasing the positive connection at least one on the drive element ( 1 ) formed engagement section ( 30a . 30b ) and the multi-part driven element ( 8th ) a carrier body ( 6 ) and at least one positive locking element, which relative to the carrier body ( 6 ) is movably guided and with the engaging portion ( 30a . 30b ) is engageable, characterized in that at least one switchable mechanical actuating mechanism ( 10 . 8a . 8b . 11a . 11b ) is provided, the at least one, as a driver ( 8a . 8b ) formed positive-locking element and which is switchable in at least two different angular ranges of the camshaft rotation and by the at least one driver ( 8a . 8b ) with the at least one engagement section ( 30a . 30b ) is engageable against a restoring force, wherein the actuating mechanism on the at least one driver ( 8a . 8b ) in the direction of engagement section ( 30a . 30b ) acting energy storage ( 10 ) and one between an actuator ( 12 ) and the driver ( 8a . 8b ), the guided movement of the driver ( 8a . 8b ) comprises a steering curve joint. Apparatus according to claim 1, wherein the at least one driver ( 8a . 8b ) in the direction of engagement section ( 30a . 30b ) projecting engagement element ( 9a . 9b ) and a relative to this offset in the axial direction ramp with a control cam ( 11a ), which with the trained as a switchable pin actuator ( 12 ) cooperates. Device according to the preceding claims, wherein the drive element ( 1 ) at least two circumferentially spaced engaging portions ( 30a . 30b ) having. Apparatus according to claim 3, wherein the at least one driver ( 8a . 8b ) with the two engagement sections ( 30a . 30b ) is alternately engageable. Apparatus according to claim 3, wherein two drivers ( 8a . 8b ) are provided, each of which one of the engaging portions ( 30a . 30b ), and wherein the drivers ( 8a . 8b ) alternately with the engaging portions ( 30a . 30b ) are engageable. Device according to the preceding claims, wherein the at least one engagement section ( 30 ) as teeth ( 4a . 4b ) and tooth gaps ( 5a . 5b ) having the gear portion is formed. Apparatus according to claim 5 or 6, wherein the two engagement sections ( 30a . 30b ) as teeth ( 4a . 4b ) and tooth gaps ( 5a . 5b ) first ( 30a ) and second gearing sections ( 30b ) are formed and the respectively not engaged driver ( 8a . 8b ) of a tooth ( 4a . 4b ) of its associated engaging portion ( 30a . 30b ) against the force of an energy store ( 10 ) is held in a waiting position. Device according to the preceding claims, wherein the at least one driver ( 8a . 8b ) relative to the carrier body ( 6 ) guided by a rotational movement, a translational movement or a combined rotational and translational movement is movable. Apparatus according to claim 8, wherein the at least one driver ( 8a . 8b ) by on the support body ( 6 ) Guided tours ( 7 ) is guided. Device according to claims 5 to 9, wherein at least one bi-directional Power storage ( 10 ), by which the two drivers ( 8a . 8b ) in each case in the direction of their associated engagement sections ( 30a . 30b ) can be acted upon by a force. Apparatus according to claim 10, wherein the energy store ( 10 ) is designed as acting in two directions spring. Device according to the preceding claims, wherein the drive element ( 1 ) is designed as a sprocket, which is drivable by the crankshaft via a drive chain. Device according to claims 1 to 12, wherein the drive element ( 1 ) is designed as a toothed belt, which is driven by the crankshaft via a toothed belt. Device according to claims 1 to 12, wherein the drive element ( 1 ) is designed as a gear, which is driven by the crankshaft via a gear transmission. Method for changing the relative angular position of a camshaft ( 2 ) with respect to a crankshaft of an internal combustion engine, in which a between at least one engagement portion having drive element ( 1 ) for driving the camshaft ( 2 ) and one with the camshaft ( 2 ) rotatably connected multi-part output element ( 8th ) provided and engageable with the at least one engaging portion in positive engagement, releasable driver connection for targeted adjustment of the relative angular position in a first adjustment in a first portion of the orbital motion of the camshaft ( 2 ) is released from its engagement, in which on the camshaft ( 2 ) is applied as a positively defined first torque, and wherein the releasable driver connection for selectively adjusting the angular position in a direction opposite to the first direction second adjustment direction in a second portion of the orbital motion of the camshaft ( 2 ) is released from its engagement, in which on the camshaft ( 2 ) bears a negative, the first torque counteracting second torque. Method according to claim 15, wherein an adjustment movement of desired length takes place in a plurality of successive sub-steps of discrete length, in that the engagement sections are in the form of teeth ( 4a . 4b ) and tooth gaps ( 5a . 5b ) are formed and the releasable driver connection at least two movable relative to the toothed portions driver ( 8a . 8b ), each having at least one engagement element ( 9a . 9b ), wherein the engagement elements ( 9a . 9b ) alternating with the tooth gaps ( 5a . 5b ) of the toothed portions are brought into positive engagement, and wherein the respective non-engaged engagement elements ( 9a . 9b ) through the respective teeth ( 4a . 4b ) of their associated toothed section ( 30a . 30b ) against the force of an energy store ( 10 ) are held in a waiting position.