ACTUATOR FOR CAM PHASER AND CAM PHASER

FIELD OF THE INVENTION

The invention relates to an actuator for a cam phaser and to a cam phaser.

BACKGROUND OF THE INVENTION

Cam phasers for internal combustion engines are well known. The cam phaser includes a hydraulic valve with a piston that is axially move able in a housing of the hydraulic valve and which controls a hydraulic loading of the cam phaser. controlling the cam phaser is typically done hydraulically by positioning the piston and releasing or closing connections provided at the housing. The piston is positioned by an electromagnetic actuator. Function specific components of the actuator like in particular a plunger for moving the piston and components for generating a magnetic field for moving the plunger are received in a housing of the actuator. Typically the housing is specific to an internal combustion engine and configured to be received at a housing section of the internal combustion engine so that a plurality of housings have to be produced in order to facilitate safe fixing of the actuator at a housing section that is typically associated with the internal combustion engine.

Thus the publication document DE 10 2013 013 659 A1 discloses a connection of an actuator with a housing section wherein a support element is configured to establish the connection wherein the retaining element includes support elements and wherein the retaining element is arranged between a actuator cover and the housing section. Since the retaining element is received with its support elements between a housing cover of the actuator and the housing section, the housing section requires a recess that is configured specifically for the retaining element so that a safe connection is facilitated between the housing and the housing section. This causes a comprehensive and thus a complex and comprehensive of the housing section to the retaining element.

BRIEF SUMMARY OF THE INVENTION

Thus, it is an object of the invention to provide an actuator for a cam phaser which is attach able in a modular manner reliably and at low cost. It is another object of the invention to provide a cam phaser that implements a reliable adjustment of the cam shaft.

The object is achieved according to the invention by an actuator for a cam phaser, the cam phaser including a hydraulic valve that is adjustable by the actuator, wherein the actuator is receivable at a housing section of a component that receives the cam phaser, wherein the actuator includes a retaining element and a housing with functionally relevant components, wherein the actuator is attached by the retaining element at the housing section, wherein the retaining element is configured separate from the housing, wherein safe positioning of the actuator at the housing section is provided by a section of the retaining element that supports the actuator at the housing section in a direction of an axial orientation of the actuator, and wherein a housing cover of the housing is at least partially arranged between the section of the retaining element and the housing section.

The object is also achieved by a cam phaser including the electromagnetic actuator described supra.

Advantageous embodiments with useful and nontrivial improvements of the invention according to the invention are provided in the respective dependent claims.

An actuator according to the invention for a cam phaser is configured receivable at a housing section of a unit receiving the cam phaser. The cam phaser includes a hydraulic valve which is adjustable by the actuator. The actuator includes a retaining element to attach the actuator at the housing section, wherein the retaining element is configured separate from the actuator. According to the invention a section of the retaining element is formed that supports the actuator in a direction of its axial extension at the housing section in order to reliably position the actuator at the housing section, wherein a housing cover of the actuator is at least partially arranged between the section of the retaining element and the housing section. This means that the actuator is supported by the retaining element at the housing section wherein a longitudinal axial position of the actuator is secured in particular. This means put differently that a functionally relevant section of the actuator which includes in particular an adjustment device for adjusting the piston and movement devices configured to cause a movement of the adjustment device, e.g. configured as a magnet arrangement and an electrically flow able coil configured to generate a magnetic field can be produced separate from the retaining element that has to be configured housing specific, wherein the housing specific actuator is provided as a combination of both components. Put differently the actuator is configured modular since the functionally relevant section can be produced separately from an attachment relevant section of the actuator.

It is an advantage that the retaining element is configured housing specific wherein however the functionally relevant section of the actuator which is enveloped by the housing cover does not have to be configured to provide fixing attachment at the housing section.

Thus the functionally relevant section of the actuator can be produced in high numbers since it is independent from the housing section and the retaining element fixing the functionally relevant section of the actuator of the housing section can be produced in a smaller number specific to the housing section.

Thus a secure housing section specific connection is implemented wherein the functionally relevant section of the actuator can be produced in high volume and thus in a cost effective manner so that the entire modular actuator, the functionally relevant section and the retaining element, can be produced overall in a cost effective manner.

The modular configuration has the additional advantage of flexible assembly which facilitates for example a quick attachment of the retaining element to proto types or production components.

The retaining element is configured for fixation at the housing section and can thus include receiving openings configured to receive fixing elements, e.g. bolts. By the same token it can include fixing devices in the form of snap elements or it can be fixed by rotary form locking, e.g. by a bayonet closure at the housing section.

Secure joining of the functionally relevant section and the retaining element can be provided in that the housing cover and the retaining element are configured in an alternating manner as an outer boundary that is oriented away from the housing section.

Thus a support of the housing cover and of the retaining element is implemented in an alternating manner relative to the housing section wherein the retaining element as well as the housing cover and thus the housing support each other in an alternating manner.

In another embodiment of the actuator according to the invention the retaining element is configured at least partially complementary to the housing which yields another safe reception of the retaining element at the housing cover and vice versa.

In another embodiment of the actuator according to the invention the retaining element is configured so that it envelops the housing essentially over its circumference, in particular over its enveloping surface. This has the advantage that the actuator is flat in an axial direction of the actuator longitudinal axis so that the actuator is characterized by small installation space requirement.

Advantageously the retaining element receives the actuator through form locking in order to reliably attach the actuator at the housing section.

In another embodiment of the actuator according to the invention a snap locking element is configured at the housing cover, advantageously at an enveloping surface of the housing so that a movement of the retaining element in the axial direction is preventable. The snap locking element provides a safe connection between the functionally relevant section of the actuator and the retaining element so that a functionally relevant section and the retaining element configured as a component can be captured and positioned during an installation of the actuator at the housing section. In another embodiment the retaining element is configured to receive a position element configured at the housing which facilitates a correct positioning of the retaining element about the housing circumference. This in turn facilitates a correct positioning of the actuator at the housing section.

The positioning element is advantageously configured as a plug in device, in particular its connection socket since the plug in device is provided for supplying energy to the actuator and respective electrical current conducting elements are provided at the housing section wherein the electrically conducting elements are to be conducted by the plug in device. This means put differently that the positioning element is configured to correctly position the actuator at the housing section with respect to a circumference of the actuator. The position safety can also be implemented in that the retaining element includes an electrical connection of the plug in device.

The retaining element is produced in a cost effective manner by an injection molding method, in particular from a plastic material.

The retaining element can be configured as a component that completely covers the housing cover however it is sufficient for reliable and safe reception of the functionally relevant section to configure the retaining element frame shaped, wherein weight savings are provided in addition to a reduced material requirement that cuts costs.

Advantageously the housing section is a section of the internal combustion engine, in particular of a cylinder head of the internal combustion engine since short distances between the actuator and the cam shaft to be adjusted can be provided which reduces reaction time and thus adjustment time.

A second aspect of the invention relates to a cam phaser with an electromagnetic actuator. According to the invention the actuator is configured as described supra. Thus, a reliable cam phaser can be implemented which provides a reliable adjustment of valve timing of the internal combustion engine which includes the cam phaser according to the invention. Since adjustment of valve timing influences fuel burn and thus emissions of the internal combustion engine a fuel burn and emissions reduced reliable internal combustion engine can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages features and details of the invention can be derived from the subsequent description of advantageous embodiments and from the drawing figures. The feature and feature combinations recited in the preceding description and the feature and feature combinations recited in the subsequent figure description and/or in the figures by themselves are not only useable in the respectively stated combination but also in other combinations or by themselves without departing from the spirit and scope of the invention. Identical reference numerals are associated with identical or functionally equivalent elements. For reasons of clarity it is possible that the elements are not provided with their reference numeral in all figures without however losing their association, wherein:

FIG. 1 illustrates an actuator according to the invention in a first embodiment;

FIG. 2 illustrates the actuator according to FIG. 1 in a perceptively view;

FIG. 3 illustrates an actuator according to FIG. 1 in a sectional view;

FIG. 4 illustrates the actuator according to FIG. 1 with a retaining element in a perspective view from below;

FIG. 5 illustrates the actuator according to FIG. 4 in a side view;

FIG. 6 illustrates the actuator according to FIG. 4 in a top view;

FIG. 7 illustrates a perspective top view of the retaining element according to the first embodiment;

FIG. 8 illustrates a sectional detail view VIII of the actuator with the retaining element according to FIG. 4;

FIG. 9 illustrates a top view of the actuator according to the invention with the retaining element in a second embodiment;

FIG. 10 illustrates a perspective top view of the actuator with the retaining element according to FIG. 9;

FIG. 11 illustrates a perspective bottom view of the actuator according to FIG. 9.

FIG. 12 illustrates a top view of the retaining element according to the second embodiment;

FIG. 13 illustrates a side view of the retaining element according to FIG. 12

FIG. 14 illustrates a perspective top view of a detail XIV of the actuator according to FIG. 9;

FIG. 15 illustrates a top view of the actuator according to the invention in a third embodiment;

FIG. 16 illustrates a side view of the actuator according to FIG. 15;

FIG. 17 illustrates a perspective top view of the actuator with its retaining element in a fourth embodiment;

FIG. 18 illustrates a perspective top view of the actuator according to the invention in a fifth embodiment;

FIG. 19 illustrates a side view of the actuator according to FIG. 18;

FIG. 20 illustrates a perspective top view of the retaining element of the actuator according to FIG. 18;

FIG. 21 illustrates a perspective view from below of the retaining element according to FIG. 20; and

FIG. 22 illustrates a side view of the retaining element according to FIG. 20.

DETAILED DESCRIPTION OF THE INVENTION

A cam phaser that is not illustrated in detail is configured to adjust a cam shaft. The cam phaser includes a hydraulic valve that is not illustrated in more detail which includes a piston that is not illustrated in more detail and which is moveable in particular in an axial direction. In order to hydraulically supply the cam phaser plural connections are provided at a housing of the hydraulic valve that receives the piston. The housing is configured substantially tubular.

The cam phaser facilitates adjusting opening and closing timing of gas control valves of an internal combustion engine that includes a cylinder head and which is not illustrated in more detail during operations.

Thus a relative angular orientation of a cam shaft that is rotate ably received in the cylinder head of the internal combustion engine and not illustrated in more detail is continuously adjusted relative to a crank shaft of the internal combustion engine that is not illustrated in more detail wherein the cam shaft is rotated relative to the crank shaft. Rotating the cam shaft moves the opening and closing timing of the gas control valves so that the internal combustion engine can develop optimum power at a respective speed.

A stator of the cam phaser is connected torque proof with a drive gear of the cam shaft. Insides of a stator base element include radially inward extending bars in uniform distances so that an intermediary space is formed between two respective adjacent bars. A vane of a rotor hub of a rotor of the cam phaser is arranged so that it protrudes into the intermediary space. Corresponding to the number of intermediary spaces the rotor hub includes a plurality of veins. Thus the veins divide each intermediary space into pressure cavities. A pressure medium, typically a hydraulic fluid is introduced into the intermediary spaces by the hydraulic valve in a controlled manner.

A pressure cavity is associated with each operating connection. Thus the first pressure cavity is associated with the first operating connection and the second pressure cavity is associated with the second operating connection. In order to adjust an angular orientation between the cam shaft and the crank shaft the pressure medium in the first pressure cavity or in the second pressure cavity is pressurized while the second pressure cavity or the first pressure cavity is unloaded. The unloading is performed through at least one tank connection, wherein the hydraulic fluid can drain through the tank connection.

The piston is moved by an actuator 10 which is configured in a first embodiment according to FIGS. 1-8, wherein a move able plunger 12 of the actuator 10 c.f e.g. FIG. 11 is axially move able along a longitudinal axis 14 of the actuator 10. The actuator 10 is configured as an electromagnetic actuator. The actuator 10 includes a pole tube 24 that is arranged within a cylindrical coil that generates a magnetic field and a housing 16. The housing 16 produced according to a plastic injection molding method so that it is possible in a cost effective manner to fabricate the housing 16 and to simultaneously insert various components of a pole yoke which provides closed magnetic flux during the injection molding method.

In order to provide the magnetic flux the coil is loadable with power through a connection socket 18 that is received at the housing 16.

The actuator 10 is configured as a preassembled unit for attachment at a housing section that is not illustrated in more detail. In the illustrated embodiments the actuator 10 is configured for attachment at a housing section of the cylinder head. This means put differently that the actuator 10 is attached at the cylinder head. By the same token the housing section can also be a partial section of the cam phaser or another component of the internal combustion engine.

In order to provide a reliable connection of the actuator 10 with the housing section the housing section includes a retaining element 20 that is independent from its function specific section wherein the retaining section is used for moving the piston and is at least partially enveloped by the housing 16 wherein the retaining element supports the function specific section in a direction of its axial extension against the housing section.

The housing section 16 includes a coil that is not illustrated in more detail which is received in a coil carrier 22. The coil carrier 22 includes a pole tube 24 which is arranged between a housing cover 26 of the housing 16 and the coil carrier 22. A connection 28 configured to supply electrical current to the coil is received in the connection socket 18 which extends at least in sections over a cover surface of the housing cover 26.

The housing cover 26 includes a covering 32 which radially envelops a pot shaped cover section 34. The covering 32 functions as a stop of the preassembled actuator 10 during assembly at the housing section.

FIG. 4 illustrates the actuator 10 according to the invention in the first embodiment assembled with its retaining element 20. The retaining element 20 which is illustrated by itself in FIG. 7 is frame shaped and includes an opening 36 that is configured complementary to an enveloping surface section 38 of the cover section 34. This means put differently that the cover element 20 is configured at least partially complementary with the housing 16.

In order to fix the actuator 10 at the housing section the actuator is positioned in a receiving opening that is provided in the housing section, wherein the covering 32 advantageously contacts the housing section with its first annular surface 40 that is oriented towards the housing section. Subsequently the retaining element 20 is placed onto the housing 16 wherein the cover section 34 is arranged in the opening 36. In order to secure the retaining element 20 at the housing 16 a snap locking element 42 is configured at the enveloping surface section 38 of the cover section 34 wherein the snap locking element is configured to prevent a movement of the support element 20 in the axial direction after fixing the retaining element 20 at the housing section since the retaining element 20 is arranged in the portion of the snap locking element 42 quasi between the housing section and the housing 16. Advantageously two snap locking elements 42 are configured that are positioned opposite to each other.

Thus, the housing cover 26 and the retaining element 20 are configured in an alternating manner over a circumference of the actuator 10 as an outer border that is oriented away from the housing section. This means put differently that a cover surface 44 defining the actuator 10 with its retaining element 20 relative to the ambient wherein the cover surface 44 is configured transversal to the longitudinal axis 14 is configured in an alternating manner by the housing cover 26 and the retaining element 20.

Another option to fix the actuator 10 at the housing section is to position the function specific section of the actuator 10 in a first step without the retaining element 20 in a predetermined receiving opening in the housing section. In order to fixate the actuator 10 at the housing section the retaining element 20 is subsequently applied to the housing 16 starting from the cover surface 30, wherein the cover section 34 is arranged in the opening 36. A second annular surface 53 of the covering 32 is arranged opposite to the first contact surface 54 and contacts the contact surface 54 at least partially. The snap locking element 42 fixates the retaining element 20 at the housing 16 and thereafter the retaining element 20 is fixated at the housing section.

Thus the retaining element 20 is configured to envelop the housing 16, in particular the housing cover 26 along its circumference in particular along its enveloping surface.

In order to receive the connection socket 18 the retaining element 20 includes a recess 46 that is unlimited on one side and configured transversal in particular perpendicular to the opening 36 wherein the recess 46 supports the connection socket 18 with three of its lateral surfaces 48. This means put differently that the retaining element 20 is configured to receive a plug in device 52 of the actuator 10 which includes the connection socket 18 and the connection 28.

In an embodiment that is not illustrated in more detail the two side surfaces 48 that are configured opposite to each other are provided with clamping elements protruding into the recess at edges 50 so that an additional retaining safety of the retaining element 20 is provided at the housing 16 in addition to the snap locking elements 42 before and during the assembly of the actuator 10 at the housing section.

The retaining element 20 is configured as an injection molded component in order to save weight and cost it is configured frame shaped and includes recesses 56 which have a rather small wall thickness wherein struts 58 are configured between the recesses 56 in order to provide stability and strength to the retaining element 20 wherein a wall thickness of the retaining element 20 is increased at portions including the struts 58 compared to the wall thickness of the recesses 56.

In order to attach the actuator 10 at the housing section receiving openings 60 are provided to receive attachment devices that are not illustrated in more detail which are configured to provide a fixing attachment of the actuator 10 at the housing section. The attachment devices can be provided in the form of bolts so that a disengage able connection of the actuator 10 with the housing section is provided. If the retaining element 20 is provided as a low cost plastic component as it is the case in the instant embodiment metal sleeves 62 are arranged in the receiving opening 60 so that a secure connection can be established. In the illustrated embodiment four receiving openings are provided. More or fewer receiving openings can be arranged wherein the number of the receiving openings 60 is configured to provide safe support of the actuator 10 at the housing section. Not every receiving opening 60 has to be used for attachment purposes. This can be handled in a flexible manner and can be adapted to the housing section.

FIG. 8 illustrates the actuator 10 with its retaining element 20 in a detail view VIII in cross section. The first contact surface 54 is arranged opposite to the second ring surface 53 and in contact therewith wherein the second contact surface 55 of the retaining element 20 is configured at a distance a from the first contact surface 54. Advantageously the distance A corresponds to a thickness D of the cover ring 32 so that a flat contact of the actuator 10 can be configured between the housing section and the actuator 10 and advantageously a seal element can be arranged between the housing section and the actuator 10.

FIGS. 9-14 illustrate the actuator 10 according to the invention in a second embodiment. The retaining element 20 is configured substantially identical to the retaining element 20 according to the first embodiment wherein the most significant distance is the reception or envelopment of the connection socket 18. Compared to the first embodiment of the actuator 10 according to the invention wherein the retaining element 20 is configured to substantially envelop the connection socket 18 in the circumferential direction. The retaining socket 18 of the second embodiment is supported in a radial direction of the actuator 10. This means put differently that an element section 64 of the retaining element 20 configured to receive the connection socket 18 extends in axial direction in circumferential direction and in radial direction.

The connection socket 18 includes a boss shaped lug 70 at its end 68 that is arranged in a portion of the actuator center 66, wherein the boss shaped lug is received and supported in the element section 64. The lug 70 can have different shapes. In the illustrated second embodiment the lug includes a rectangular cross section. By the same token the lug could also have a circular or oval or another cross section. Accordingly the lug 46 is configured complementary to the cross section.

It is appreciated that the reception of the connection socket 18 or of the plug in device 52 in the retaining element 20 provides secure positioning of the actuator 10 at the housing section. This means put differently that a position of the actuator 10 relative to the housing section can be safely provided by a positioning element that is configured at the housing 16 or at the retaining ring 20 wherein the positioning element in the instant embodiment is the connection socket 18 or the plug in device 52.

In FIGS. 15 and 16 the actuator 10 according to the invention is illustrated in a third embodiment. The connection socket 18 is configured in the portion of the lug 70 differently from the connection socket 18 of the second embodiment, wherein the lug 70 is configured without distance between the cover surface 30. Thus as a protrusion in a direction of the longitudinal axis 14.

In FIGS. 17-22 which illustrate a fourth embodiment of the actuator 10 according to the invention the connection socket 18 is enveloped by the retaining element 20. Put differently this means that the connection socket 18 is configured integrally in one piece together with the retaining element 20. Thus the retaining element 20 includes an electrical connection of the plug in device 52. In order to supply energy and to correctly position the actuator 10 at the housing section the connection 28 of the plug in device 52 is configured at the cover surface 30. When assembling the actuator 10 joining the connection with a connection plug that is not illustrated in more detail and which is configured complementary to the connection 28 and which is arranged in the connection socket 18 configured at the support element 20 the connection of the retaining element 20 at the housing 16 is stabilized in addition to the snap lock connection implemented by the snap locking elements 42.

Through the retaining element 20 the actuator 10 can be attached at the housing section easily and can be disengaged from the housing section in a simple manner. Furthermore a seal element that is not illustrated in more detail is arranged between the retaining element 20 and the housing section. In the illustrated embodiment the actuator 10 is attached at the housing section through a threaded connection. By the same token the retaining element 20 can include devices for establishing a snap locked connection and/or a rotary connection, in particular a bayonet connection instead of the receiving opening 60.

REFERENCE NUMERALS AND DESIGNATIONS

- 10 actuator
- 12 plunger
- 14 longitudinal axis
- 16 housing
- 18 connection socket
- 20 retaining element
- 22 coil carrier
- 24 pole tube
- 26 housing cover
- 28 connection
- 30 cover surface
- 32 cover ring
- 34 cover section
- 36 opening
- 38 enveloping surface section
- 39 enveloping surface
- 40 first annular surface
- 42 snap locking element
- 44 cover surface
- 46 recess
- 48 lateral surface
- 50 edge
- 52 insertion device
- 53 second annular surface
- 54 first contact surface
- 55 second contact surface
- 56 recess
- 58 strut
- 60 receiving opening
- 62 metal sleeve
- 64 element section
- 66 actuator center
- 68 end
- 70 lug
- A distance
- D thickness

ACTUATOR FOR CAM PHASER AND CAM PHASER

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CPC

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Abstract

Description

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RELATED APPLICATIONS

Provisional Applications (1)