DE102019131779A1 - Electric camshaft adjuster with improved camshaft connection and method for manufacturing the camshaft adjuster - Google Patents

Abstract

The invention relates to an electric camshaft adjuster (1) for a motor vehicle drive train, with a drive wheel (2) that can be driven by endless traction means and an output ring gear (3) that is arranged coaxially to the drive wheel (2) and rotatable by an electric motor relative to the drive wheel (2) ) has an axially extending extension (4) which has a bearing point (5) for radial support on a housing (6) and is prepared for attachment to a camshaft (7), the extension (4) having a seat ( 20) for mounting the camshaft (7). The invention also relates to a method for producing a camshaft adjuster (1).

Description

The invention relates to an electric camshaft adjuster for a motor vehicle drive train. The camshaft adjuster is used to adjust the phase position of a camshaft relative to a crankshaft. The camshaft adjuster has an endless traction means drivable drive wheel and an output ring gear that is arranged coaxially to the drive wheel and rotatable relative to the drive wheel by an electric motor. The output ring gear has an axially extending extension which has a bearing point for radial support on a housing and is prepared for attachment to a camshaft.

Electric camshaft adjusters usually have a stator housing / drive wheel that can be rotatably coupled to the crankshaft, an output ring gear that can be rotated with the camshaft and rotated relative to the drive wheel, and an electric actuating unit for controlling the rotation of the output ring gear relative to the drive wheel / stator housing. The actuating unit has an adjusting gear which is coupled to the camshaft. The actuating assembly can have, for example, an electric motor, an adjusting gear coupled to the output ring gear, and a clutch coupling the electric motor to the adjusting gear.

Such an electric camshaft adjuster is, for example, from DE 10 2004 062 037 A1 known. It discloses a camshaft adjuster for adjusting the relative rotational angle position of a camshaft with respect to the crankshaft of an internal combustion engine, with an electric actuating unit and an adjusting gear which is in drive connection with a drive wheel driven by the crankshaft, the adjusting gear being connected to the engine lubrication circuit and a sealing element has sealed housing from the environment.

One problem with camshaft adjusters is that the additional connecting elements, such as a central screw, a laser structure at the parting line in the screw connection, a camshaft end piece that has to be connected to the camshaft, and a screwing process at the customer's facility are necessary to establish the connection between the electrical camshaft adjuster and the camshaft is laboriously manufactured. In addition, previous connections between the camshaft and the camshaft adjuster cause tension in the output ring gear and take up the additional installation space within the transmission, such as for the screw head of the central screw radially inside in the inner ring of the adjustment shaft of the transmission.

It is therefore the object of the invention to avoid or at least mitigate the disadvantages of the prior art. In particular, an electric camshaft adjuster and a method for producing / assembling the same are to be provided in which the above-mentioned system elements do not have to be transported through the camshaft and the connection of the camshaft to the camshaft adjuster is improved.

This object is achieved according to the invention in a device of the generic type in that the extension has a seat on its outer surface for mounting the camshaft. This means that the camshaft, in particular a tubular section of the camshaft, can be attached directly to the seat for the extension, i.e. without an additional camshaft end piece and / or a central screw. In other words, the output ring gear is designed according to the invention in such a way that the camshaft (instead of an axial screw fastening) can be attached to the drive ring gear via a direct non-positive, positive, frictional or material connection, for example by gluing or welding. It is therefore possible to provide a secure connection between the drive ring gear and the camshaft, which connection can also be produced particularly inexpensively. The ring gear is preferably designed in such a way that the camshaft can be attached without a fastening device, i.e. without a separate fastening device such as a screw, etc.

This has the advantage that both the connecting elements such as a central screw, a laser structure on the parting line in the screw connection, a camshaft end piece that has to be connected to the camshaft, and a screwing process at the customer in the final assembly to establish the connection between the electrical camshaft adjuster and to produce the camshaft, can be omitted. Because the camshaft can be mounted or fastened directly on the outer surface of the extension, namely via the seat, on the camshaft adjuster, in particular the output ring gear, additional fastening elements are not required. This in turn has the advantage that no stresses and / or deformations are introduced into the output ring gear by the fastening elements that are no longer required and that additional installation space can be gained in the transmission.

Advantageous embodiments are claimed in the subclaims and are explained in more detail below.

According to a preferred embodiment, the outer surface of the extension can be designed to bear against a radial inner surface of the camshaft. This means that the extension in the camshaft is inserted or the camshaft is placed on the extension. In particular when the camshaft is designed with a camshaft tube / tube section, the rigidity of the tube section can thus be additionally improved.

According to an alternative preferred embodiment, the inner surface of the extension can be designed to bear against a radial outer surface of the camshaft. This means that the extension is inserted into the camshaft. This means that the extension is placed on the camshaft or the camshaft is inserted into the extension.

In an advantageous development, the extension can have knurling in the area of the seat. This has the advantage that, on the one hand, the surface area of the extension is increased in the area of the seat and, on the other hand, a knurled connection can be established between the camshaft and the extension. Such a knurled connection has a considerably higher strength, in particular against rotation, compared to a smooth connection. The knurling can preferably extend completely over the circumference of the extension. This achieves a particularly high level of strength that is uniform over the circumference.

It is particularly preferred if an area with a centering surface for centering the output ring gear with respect to the camshaft is provided axially adjacent to the knurling on the extension during the assembly process. The centering surface is preferably arranged on an axial side of the knurling facing the camshaft.

In addition, it is preferred if a camshaft is attached to the seat, the knurling in the area of the seat being pressed into the camshaft with a press overlap. This means that the output ring gear is preferably connected to the camshaft via a knurled interference fit. This enables a plasto-elastic connection between the camshaft and the output ring gear, which cannot be released, i.e. cannot be released without damage.

It is also advantageous if the camshaft adjuster has a closed machine element that encompasses the circumference of the camshaft, i.e. uninterrupted / circumferential in the circumferential direction and that forms an interference fit with the camshaft in an area radially outside the seat. The machine element can be formed, for example, by a transmitter wheel / trigger disk or a cam on the camshaft. Because the machine element is arranged directly radially outside the seat, i.e. at the same axial height, a counteracting force can be applied by the interference fit between the camshaft and the output ring gear. The deformations and / or stresses in the camshaft tube are thus reduced. In addition, the press connection between the camshaft and the output ring gear can also be increased as a result.

It is also useful if the interference fit between the camshaft and the machine element is matched to the interference fit between the output ring gear and the camshaft in such a way that the stresses arising from the interference fit and the interference fit are (predominantly) balanced out. This allows tensions in the camshaft to be avoided.

It is also preferred if the extension has a higher material strength than the camshaft. This makes it easier for the extension to be pressed into the softer material of the camshaft.

It is also advantageous if the extension has a contour in order to force a permanent, preferably plasto-elastic, bond between the camshaft and the output ring gear when the camshaft is placed on the seat for the camshaft provided by the extension. The knurling forms such a contour, for example.

The object of the invention is also achieved by a method for producing a camshaft adjuster according to the invention, a preassembly of a radial shaft sealing ring, a roller bearing and a transmitter gear on the axial extension of the output ring gear before producing a knurled interference fit between the extension and a pipe section of the camshaft. As a result, the radial shaft sealing ring, the roller bearing and / or the encoder wheel do not have to be transported through the camshaft.

According to a further aspect of the invention, the extension of the output ring gear can have at least one, for example at least partially radial, oil inlet channel for supplying lubricating oil, at least one, for example at least partially radial, oil drain channel for draining the lubricating oil. In other words, at least one oil drainage channel is formed in the extension of the output ring gear, through which oil can be drained from an interior of the output ring gear to the outside. This means that the (lubricating) oil can be guided through the oil drain channel, in particular outside the output ring gear, preferably outside an entire oil-tight system of the camshaft adjuster, particularly preferably inside the motor housing in which the camshaft adjuster is mounted. The at least one oil inlet channel and / or the at least one oil drain channel are / is preferably aligned exactly in the radial direction, since this enables particularly simple introduction. The lubricating oil is guided, in particular from a so-called P-channel, through the at least one oil inlet channel into a radially inner cavity of the output ring gear. The lubricating oil is fed from the cavity, for example, to an adjusting gear and / or a clutch of the camshaft adjuster, a radial bearing area between the output ring gear and the drive gear and / or a radial bearing area between the output ring gear and a sealing cover of the camshaft adjuster and / or to an electric motor. By providing the at least one oil drainage duct according to the invention, the back pressure of the lubricating oil that is introduced into the electrical camshaft adjuster sealed off from the outside is reduced. This has the advantage that a build-up of the oil back pressure prevents or that the oil back pressure can be reduced or dissipated by the provision of the at least one oil drain channel, in that the lubricating oil can be led through the oil drain channel to the outside, ie out of the sealed area of the camshaft adjuster . This avoids damaging the seals used to seal a wet area of the camshaft adjuster.

According to a preferred embodiment, the at least one oil drain channel can be arranged closer to the end of the extension on the camshaft side than the at least one oil inlet channel. The drained oil can thus be carried away more easily in the direction of the camshaft or a space outside the housing. Preferably, the at least one oil drain channel is accordingly arranged on an axial side of the bearing on the camshaft side.

Alternatively, it is also possible for the at least one oil inlet duct to be arranged closer to the end of the extension on the camshaft side than the at least one oil drain duct. This means that the at least one oil drain channel is arranged closer to the bearing point of the extension than the at least one oil inlet channel. The oil drain channel can preferably be arranged axially (directly) next to the bearing point for the camshaft. The drained oil can then be carried away via a bearing arranged at the bearing point and from there through the motor housing. However, this has the disadvantage that contamination of the camshaft adjuster is then carried along with the drained oil into the bearing, such as a roller bearing, arranged at the bearing point.

The extension of the output ring gear has an end section which is designed such that it is arranged outside the housing in the assembled state of the camshaft adjuster. According to a preferred embodiment, the at least one oil drain channel, in particular at least one opening to a radial outside of the extension, can be arranged in the end section. This has the advantage that the drained oil is guided directly in an area outside the motor housing, and thus, for example, an endless traction means connected to the drive wheel does not come into contact with oil.

According to an advantageous embodiment, the at least one oil inlet channel and / or the at least one oil drain channel can fluidically connect a radial outside of the extension to a radial inside of the extension. This means that the oil can be introduced into a cavity of the output ring gear from the outside, for example via a P channel in the housing. From the cavity, the oil can be fed to the components to be lubricated and / or connection points of the camshaft adjuster. The oil can be drained / drained out of the cavity through the oil drain channel. This has the advantage that the system, which is sealed off from the outside and formed in particular by the cavity and the components to be lubricated arranged inside the camshaft adjuster, is provided with an oil drain formed by the oil drain channel, so that the back pressure is considerably reduced. In other words, the channels for supplying and draining the lubricating oil into and out of the camshaft adjuster run directly in the output ring gear. This means that the ducts can be integrated almost without taking up any space.

In addition, it is advantageous if the extension has a large number of oil inlet channels and / or a large number of oil drainage channels. As a result, the oil can be introduced into the cavity or discharged from it in a suitable manner. It is further preferred if the plurality of oil inlet channels run in a common first plane. The first plane can in particular be a radial plane that is perpendicular to an axis of the camshaft adjuster. Alternatively or additionally, it is preferred if the plurality of oil drainage channels run in a common second plane. The second plane can in particular be a radial plane that is perpendicular to an axis of the camshaft adjuster. This has the advantage that the oil is introduced axially at the same height but over the circumference via the multiple oil inlet channels or discharged via the multiple oil drain channels, so that the oil can be passed on from there in a better and more controlled manner. It is further preferred if the first plane is parallel and axially spaced from the second plane.

It is also expedient if the multiplicity of oil inlet channels are aligned in the same way and / or the multiplicity of oil drain channels are aligned in the same way. This means that the oil inlet channels or the oil drain channels can also be arranged axially parallel to one another.

According to a preferred embodiment, the at least one oil drain channel can be designed relative to the at least one oil inlet channel in such a way that it achieves a throttling effect. As a result, the oil flow can be directed into the output ring gear and out of the output ring gear in a suitable manner.

According to a preferred embodiment, the at least one oil drain channel can have a smaller diameter, or at least a smaller cross section, than the at least one oil inlet channel. A throttling effect can thereby be achieved in a simple manner. Alternatively, the number of oil inlet channels can be greater than the number of oil outlet channels. In other words, it is crucial that a total flow through the oil inlet channels into the output ring gear is greater than a total flow through the oil drain channels out of the output ring gear.

In a specifically shown development, the drive wheel is in operative contact with a dry-running belt. This means that the electric camshaft adjuster is used in a drying belt system. Particularly when used in a drying belt system, it is crucial that the seals used are not damaged, otherwise the belt can be wetted with oil. The drive wheel can also be in operative contact with a wet chain. This means that the electric camshaft adjuster is used in a chain system.

It is particularly preferred if a wet space formed within the camshaft adjuster, into which the oil can be introduced via the oil inlet duct and drained from the oil via the oil drain duct, via a first radial shaft sealing ring which is placed on a first sealing cover connected to the drive wheel in a rotationally fixed manner, and / or by means of a second radial shaft sealing ring, which is placed on a second sealing cover connected in a rotationally fixed manner to the drive wheel, can be sealed off from the housing. The first sealing cover is preferably arranged on an axial side of the drive wheel facing away from the camshaft. The second sealing cover is preferably arranged on an axial side of the drive wheel facing the camshaft. In other words, there is a fluid connection between the at least one oil inlet channel and a radial shaft sealing ring placed on a first sealing cover connected to the drive wheel. In other words, there is a second sealing cover on the opposite side of the drive wheel, between which and the housing a further radial shaft sealing ring is inserted in a sealing manner.

In other words, the invention relates to an electric camshaft adjuster with an improved camshaft connection and with an improved lubricating oil supply.

On the one hand, the camshaft adjuster according to the invention can solve the problem that the assembly of the camshaft adjuster is time-consuming, since individual system elements such as a radial shaft sealing ring, a roller bearing and / or a sensor wheel must be transported through the entire camshaft to the installation site. According to the invention, a non-detachable knurled interference fit is formed between the electric camshaft adjuster and the camshaft or the camshaft body. The interference fit forms a plasto-elastic connection and can therefore not be released without damage. Alternatively or additionally, an adhesive and / or welded connection can be provided between the electric camshaft adjuster and the camshaft. The pre-assembly of the radial shaft sealing ring, the roller bearing and the encoder wheel on the axial extension of the output ring gear takes place before the knurled interference fit is produced. This means that no further assembly of the system elements is required when assembling the motor. The extension of the output ring gear has at its end (on the right in the figures) a knurled section with which the output ring gear is pressed axially into the tube of the assembled camshaft with a press overlap. The knurling can also be hardened so that the knurled toothing engages plasto-elastically in the softer camshaft tube and creates a play-free form fit with the camshaft tube. This has the advantage that connecting elements such as a central screw, a laser structure or a camshaft end piece as well as a screwing process at the customer's can be dispensed with. The press connection can be strengthened by a trigger disk / encoder wheel placed on the camshaft tube in the axial area of the press connection. In addition, by eliminating the screw connection, the stresses and deformations in the output ring gear can be reduced. Furthermore, by eliminating the central screw head, the rigidity of an inner ring of the rolling bearing in the transmission can be increased by reducing the inner diameter of the inner ring in the additional installation space.

On the other hand, the camshaft adjuster according to the invention can solve the problem that a back pressure in the outwardly sealed wet space / wet area of the camshaft adjuster through the supply line of the lubricating oil the P-channel on the radial camshaft bearing leads to leakage or wear of the sealing lips of radial shaft seals. According to the invention, drainage openings are provided at the end of the axial extension of the output ring gear. A build-up of dynamic pressure by feeding the lubricating oil into the oil-tight mechanical transmission can thus be prevented, as the excess lubricating oil is diverted back into the engine interior via several drain holes at the end of the axial extension of the output ring gear axially to the right outside the camshaft radial bearing. This also has the advantage that the oil lubrication supply and drainage channels run directly in the output ring gear.

• 1 eine Längsschnittdarstellung eines erfindungsgemäßen Nockenwellenverstellers in einem Nockenwellenverstellsystem,
• 2 eine Längsschnittdarstellung des Nockenwellenverstellers,
• 3 eine Längsschnittdarstellung eines Abtriebshohlrads des Nockenwellenverstellers,
• 4 eine perspektivische Darstellung des Abtriebshohlrads,
• 5 eine zur 4 gedrehte, perspektivische Darstellung des Abtriebshohlrads, und
• 6 eine perspektivische Darstellung eines Ausschnitts des Nockenwellenverstellsystems.

The invention is explained below with the aid of drawings. Show it:

• 1 a longitudinal sectional view of a camshaft adjuster according to the invention in a camshaft adjustment system,
• 2 a longitudinal sectional view of the camshaft adjuster,
• 3rd a longitudinal sectional view of an output ring gear of the camshaft adjuster,
• 4th a perspective view of the output ring gear,
• 5 one to 4th rotated, perspective view of the output ring gear, and
• 6th a perspective view of a section of the camshaft adjustment system.

The figures are merely of a schematic nature and serve exclusively for the understanding of the invention. The same elements are provided with the same reference symbols. The features of the individual embodiments can be interchanged with one another.

1 and 2 show an electric camshaft adjuster according to the invention 1 for a motor vehicle drive train. The camshaft adjuster 1 has a drive wheel 2 on. The drive wheel 2 can be driven endlessly. The drive wheel 2 is connected to a crankshaft, not shown. The camshaft adjuster 1 has a coaxial with the drive wheel 2 arranged output ring gear 3rd on. The output ring gear 3rd is relative to the drive wheel 2 Can be rotated by an electric motor. The output ring gear 3rd has this axially extending extension 4th on. At the appendix 4th is a depository 5 for radial support on a housing 6th educated. The appendix 4th is for attachment to a camshaft 7th prepared. The extension preferably has 4th a higher material strength than the camshaft 7th .

According to the invention, the extension has 4th at least one oil inlet channel which is at least partially oriented in the radial direction 8th and at least one oil drain channel which is at least partially aligned in the radial direction 9 . The oil inlet duct 8th is in particular aligned exactly in the radial direction. The oil drain channel 9 is in particular aligned exactly in the radial direction. Via the oil inlet duct 8th oil such as lubricating oil can be supplied. Via the oil drain channel 9 the oil can be drained away. Inside the camshaft adjuster 1 is a wet room 10 formed, in which via the oil inlet duct 8th introduced lubricating oil is located. The wet room 10 is sealed to the outside. Through the oil drain channel according to the invention 9 is the oil from the wet room 10 diverted so that a back pressure is reduced.

The oil inlet duct 8th connects a radial outside of the output ring gear 3rd with a radial inside of the output ring gear 3rd . The oil drain channel 9 has an input that leads to an area radially outside of the output ring gear 3rd is open, and an exit that leads to a cavity 11 of the output ring gear 3rd is open. The oil inlet duct 8th So opens into the cavity 11 of the output ring gear 3rd . The cavity 11 is therefore part of the wet room 10 . The oil drain channel 9 connects the radial inside of the output ring gear 3rd with the radial outside of the output ring gear 3rd . The oil drain channel 9 so has an entrance that leads to the cavity 11 is open, and an output that leads to the area radially outside of the output ring gear 3rd is open.

The at least one oil drainage channel 9 closer to a camshaft-side end of the extension 4th is arranged as the at least one oil inlet channel 7th . Alternatively, the at least one oil inlet channel can 8th closer to the camshaft end of the extension 4th be arranged as the at least one oil drainage channel 9 , even if this is not shown in the figures. The oil drain channel 9 is on an axial side of the bearing on the camshaft side 5 arranged. The oil drain channel 9 can also be in the axial area of the bearing point 5 be arranged, even if this is not shown in the figures. The oil inlet duct 8th is on an axial side of the bearing on the camshaft side 5 arranged.

The appendix 4th has an end portion 12th , which is designed so that it is in the assembled state of the camshaft adjuster 1 outside the case 6th is arranged, wherein the at least one oil drainage channel 9 in the end section 12th is arranged. So that means that the camshaft adjuster 1 in the case 6th is stored, the wet room 10 opposite a drying room 13th in the case 6th is sealed. The end section 12th of the output ring gear 3rd protrudes from the housing (when installed) 6th out. The oil drain channel 9 or at least the outlet of the oil drainage channel 9 is in the end section 12th arranged so that the lubricating oil through the oil drain passage 9 out of the case 6th can be guided out. The lubricating oil is therefore not in one place within the housing 6th , ie not in the drying room 13th , from the output ring gear 3rd diverted. Alternatively, it is possible to use the oil drainage channel 9 to be arranged so that the lubricating oil flows through a channel in the housing 6th from the drying room 13th or from the camshaft adjuster 1 is feasible.

In the embodiment shown, the output ring gear 3rd a variety of oil inlet ports 8th on. In the embodiment shown, the output ring gear 3rd a variety of oil drainage channels 9 on. The oil inlet ducts 8th are aligned in the radial direction. The oil inlet ducts 8th are arranged in a common first plane. The first plane is therefore a radial plane that is perpendicular to an axis of rotation of the camshaft adjuster 1 is. The oil inlet ducts 8th are evenly distributed over the circumference of the extension. The oil inlet ducts 8th each have the same cross-section. The oil inlet ducts 8th lead from a ring channel 14th that is in the case 6th is formed in the cavity 11 . The oil is via a P-channel, not shown, which is in the housing 6th is arranged in the annular channel 14th initiated. The oil drainage channels 9 are aligned in the radial direction. The oil drainage channels 9 are arranged in a common second level. The second plane is therefore a radial plane that is perpendicular to an axis of rotation of the camshaft adjuster 1 is. The first plane and the second plane are parallel and axially offset from one another. The oil drainage channels 9 are evenly distributed over the circumference of the extension. The oil drainage channels 9 each have the same cross-section.

The at least one oil drainage channel 9 is so relative to the at least one oil inlet channel 8th designed that it achieves a throttling effect. In the embodiment shown, the oil drain channel 9 (or the oil drainage channels 9 ) has a smaller diameter than the oil inlet port 8th (or as the oil inlet ports 8th ) on.

The drive wheel 2 stands with a dry running belt 15th in operative contact. The torque is via the belt 15th in the camshaft adjuster 1 initiated. The strap 15th is in the drying room 13th arranged. Alternatively, the drive wheel 2 be driven via a wet chain, for example, even if this is not shown.

The one inside the camshaft adjuster 1 trained wet room 10 is to the drying room 10 sealed. These are between the camshaft adjuster 1 and the case 6th Seals provided. The wet room 10 is via a first radial shaft seal 16 to the housing 6th towards, that is, to the one inside the housing 6th trained drying room 13th , sealed. The first radial shaft seal 16 is on a first sealing cover 17th (radially outside) attached. The first sealing cover 17th is with the drive wheel 2 non-rotatably connected. The first sealing cover 17th is on an axial side of the drive wheel facing away from the camshaft 2 arranged. The wet room 10 is via a second radial shaft seal 18th to the housing 6th towards, that is, to the one inside the housing 6th trained drying room 13th , sealed. The second radial shaft seal 18th is on a second sealing cover 19th (radially outside) attached. The second sealing cover 19th is with the drive wheel 2 non-rotatably connected. The second sealing cover 19th is on an axial side of the drive wheel facing the camshaft 2 arranged.

According to the invention, the extension has 4th a seat on its outer surface 20th for a bearing of the camshaft 7th . That is, a pipe section 21 the camshaft 7th right at the seat 20th is applied. The outer surface of the appendix 4th is therefore to rest against a radial inner surface 22nd the camshaft 7th or the pipe section 21 designed. In other words, it is the appendix 4th of the output ring gear 3rd directly, ie not via an intermediate piece, such as a camshaft end piece, with the pipe section 21 connected. On the circumference of the pipe section 21 are cams of the camshaft 7th attached directly.

3rd to 5 show different views of the output ring gear 3rd . The seat 20th in at the end portion 12th of the appendix 4th educated. The seat 20th is on a collar 22nd educated. The collar 22nd forms one axial end of the extension 4th . The appendix 4th points in the area of the collar 22nd has a smaller outer diameter than in a region axially spaced apart therefrom, such as, for example, in a region of the bearing point 5 . In the illustrated embodiment of the extension 4th axially joins a bearing area 23 in which the depository 5 is arranged, an intermediate area 24 at. To the intermediate area 24 the collar closes axially 22nd at. The cavity 11 does not extend axially to the collar 22nd .

The appendix 4th owns in the area of the seat 20th a knurling 25th . The knurling 25th is on an outer surface of the seat 20th educated. The knurling 25th extends completely over the perimeter of the appendix 4th . The knurling 25th has a first knurled portion 26th and a second knurled portion 27 on. The first knurled section 26th serves as a centering surface for centering the output ring gear 3rd to the camshaft 7th . The first knurled section 26th is therefore used for centering during the pressing in / during the assembly process in the pipe section 21 . The first knurled section 26th is closer to the axial end of the extension facing the camshaft 4th than the second knurled section 27 arranged. The first knurled section 26th has a smaller outer diameter than the second knurled portion 27 on. The second knurled section 27 creates an interference fit with the camshaft 7th . Thus, the second knurled section is used 27 than the knurled interference fit.

The appendix 4th has a contour to when placing the camshaft 7th on the seat provided by the continuation 20th for the camshaft 7th a permanent, preferably plasto-elastic, connection of the camshaft 7th with the output ring gear 3rd to force. The plasto-elastic composite is created by pressing in the knurling 25th in the pipe section 21 the camshaft 7th educated.

The collar 22nd goes over a step 28 in the intermediate section 24 above. The outside diameter of the appendix 4th increases from the outside diameter of the collar 22nd over the axial step 28 . The camshaft 7th lies in the mounted step on an axial face of the step 28 at. The stage 28 so serves as a thrust bearing for the camshaft 7th . In the area of the step 28 is for better production of the knurling 25th an undercut formed.

The camshaft adjuster 1 possesses one over the circumference of the camshaft 7th encompassing and closed machine element 29 . Closed means that the machine element 29 is formed continuously / circumferentially in the circumferential direction. In the embodiment shown, the machine element is 29 by a transmitter wheel 30th / a trigger wheel / a trigger disk formed. The machine element 29 can also be formed by a cam, even if this is not shown. The encoder wheel 30th is right on the circumference of the pipe section 21 attached. The machine element 29 is via an interference fit on the camshaft 7th attached. The machine element 29 is axial in the area of the seat 20th arranged. That is, the machine element 29 in an area just radially outside the seat 20th on the camshaft 7th is upset.

The interference fit between the camshaft 7th and the machine element 29 is so on the press overlap between the output ring gear 3rd , especially the seat 20th , and the camshaft 7th coordinated so that the tensions created by the interference fit and the interference fit are largely balanced out. This means that the voltages are essentially the same. The tensions essentially act in opposite directions.

A method according to the invention for producing the electric camshaft adjuster 1 will be discussed below with reference to 2 described. Before making the connection of the camshaft 7th with the camshaft adjuster 1 a pre-assembly takes place. A radial shaft seal, here the second radial shaft seal 18th is in the pre-assembly on the output ring gear 3rd , here on the appendix 4th , postponed. A camp, here one on the camp site 5 mounted roller bearing 31 , is in the pre-assembly on the output ring gear 3rd postponed. Also the encoder wheel 20th can be attached to the output ring gear during pre-assembly 3rd be postponed. After the pre-assembly, the connection of the camshaft is used 7th with the camshaft adjuster 1 a knurled interference fit between the appendage 4th and the pipe section 21 the camshaft 7th generated. This is done by the seat 20th with the knurling 25th pressed into the pipe section. This creates a plasto-elastic connection between the extension 4th and the camshaft 7th produced.

List of reference symbols

1

Camshaft adjuster

2

drive wheel

3

Output ring gear

4th

Appendix

5

Depository

6th

casing

7th

camshaft

8th

Oil inlet port

9

Oil drain channel

10

Wet room

11

cavity

12th

End section

13th

Drying room

14th

Ring channel

15th

belt

16

first radial shaft seal

17th

first sealing cover

18th

second radial shaft seal

19th

second sealing cover

20th

Seat

21

Pipe section

22nd

collar

23

storage area

24

Intermediate area

25th

Knurling

26th

first knurled section

27

second knurled section

28

step

29

Machine element

30th

Encoder wheel

31

roller bearing

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102004062037 A1 [0003]

Claims (10)

Electric camshaft adjuster (1) for a motor vehicle drive train, with a drive wheel (2) that can be driven by endless traction means and an output ring gear (3) which is arranged coaxially to the drive wheel (2) and rotatable by an electric motor relative to the drive wheel (2), the output ring gear (3) having one of these axially lengthening extension (4) which has a bearing point (5) for radial support on a housing (6) and is prepared for attachment to a camshaft (7), characterized in that the extension (4) has a seat (20) on its outer surface ) for mounting the camshaft (7). Camshaft adjuster (1) Claim 1 , characterized in that the outer surface of the extension (4) is designed to bear against a radial inner surface of the camshaft (7). Camshaft adjuster (1) Claim 1 , characterized in that the inner surface of the extension (4) is designed to bear against a radial outer surface of the camshaft (7). Camshaft adjuster (1) according to one of the Claims 1 to 3rd , characterized in that the extension (4) has knurling (25) in the area of the seat (20). Camshaft adjuster (1) Claim 4 , characterized in that axially adjacent to the knurling (25, 26) on the extension (4) an area with a centering surface (25, 27) for centering the output ring gear (3) to the camshaft (7) is provided. Camshaft adjuster (1) Claim 4 or 5 , characterized in that a camshaft (7) is attached to the seat (20), the knurling (25, 26) in the area of the seat (20) being pressed into the camshaft (7) with a press overlap. Camshaft adjuster (1) Claim 6 , characterized in that the camshaft adjuster (1) has a closed machine element (29, 30) which encompasses the circumference of the camshaft (7) and which forms an interference fit with the camshaft (7) in an area radially outside the seat (20) . Camshaft adjuster (1) Claim 6 or 7th , characterized in that the extension (4) has a higher material strength than the camshaft (7). Camshaft adjuster (1) according to one of the Claims 6 to 8th , characterized in that the extension (4) has a contour in order to create a permanent connection between the camshaft (7) and the camshaft (7) when the camshaft (7) is placed on the seat (20) for the camshaft (7) provided by the extension (4) To force output ring gear (3). Method for producing an electric camshaft adjuster (1) according to one of the Claims 1 to 9 , whereby a pre-assembly of a radial shaft sealing ring (18), a roller bearing (31) and a sensor wheel (30) on the axial extension (4) of the output ring gear (3) before the production of a knurled interference fit between the extension (4) and a pipe section (21) a camshaft (7) takes place.

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