EP1544420B1 - Internal combustion engine with hydraulic camshaft phasing device - Google Patents

Abstract

The device has a rotor (6) with blades (10) fastened to the camshaft (2), and a stator (4) with end wall (5) fastened to a drive pulley (3) driven by the crankshaft. The stator, esp. its web walls, and its inner and outer peripheral walls, is a metal plate or band part, formed by a non-cutting process. The stator has local reinforcements of profiles, beads, etc. extending along direction of special loads. Stator, outer stator housing (13), and drive pulley are fastened to each other by e.g. forming technology. Pressure chambers between stator and rotor are closed at one end by a metal sealing plate (14). Hollows or cutouts in stator walls are filled with metal foam or injected plastic.

Description

Field of the invention

The invention relates to an internal combustion engine having a hydraulic device for adjusting the rotational angle of a camshaft relative to a crankshaft, comprising: a rotor with vanes disposed thereon, which is non-rotatably connected to the camshaft, a frontally provided with an end wall stator, the rotationally fixed with a driven by the crankshaft Drive wheel is connected, wherein on both sides of the wing pressure chambers are provided which are each bounded by web walls and inner and outer, in the circumferential direction, concentrically extending walls of the stator and are pressurizable or emptied via a hydraulic system with hydraulic fluid.

Background of the invention

From the DE 101 34 320 A1 is an internal combustion engine with a generic Hydraulic device for adjusting the rotational angle of a camshaft known that can change the phase angle of a camshaft relative to a crankshaft. This device consists of a rotor and a stator, of which the former, designed as an impeller, comprises the camshaft and rotates synchronously with it. The stator is on the one hand closed by a front wall, which may be part of a housing surrounding the stator, and on the other hand by a drive wheel pressure-sealed. It includes the rotor and rotates synchronously with the driven by the crankshaft drive wheel. Essentially radially extending web walls in the stator allow only a limited angle of rotation of the rotor and form with this a plurality of pressure chambers, which can be pressurized with hydraulic fluid or emptied.

1. 1. eine hohe Masse der Vorrichtung zur Drehwinkelverstellung,
2. 2. hohe Fertigungskosten durch den Zerspanungsaufwand bei der Fertigung der Sinterbauteile,
3. 3. eine unerwünschte, externe Ölleckage durch die porösen Sinterbauteile.

A disadvantage of this known device, however, is that the items of the device mainly consist of steel or iron, which are made by sintering or machining. This results

1. 1. a high mass of the device for adjusting the rotational angle,
2. 2. high production costs due to the machining outlay during the production of the sintered components,
3. 3. undesirable external oil leakage through the porous sintered components.

Because thin wall thicknesses, especially in connection with wall thickness variations in density distribution and strength and rigidity are problematic in the sintered metallurgy and can continue to realize complex shapes with different filling heights often only with expensive sliders in the tool, previous devices for adjusting the angle are usually made of relatively heavy and solid components manufactured. In machined devices, the problem is similar; complicated, adapted to the load shapes are associated with high machining costs.

A proposal for reducing the weight of the device for adjusting the rotational angle, for example, the DE 101 48 687 A1 or the DE 101 34 320 A1 can be removed by parts of the device made of aluminum or an aluminum alloy or another light metal. This has the disadvantage that due to different coefficients of thermal expansion, the leakage gaps can increase over the heating and thus results in a high leakage. In addition, with the same dimensions, aluminum deforms more under load than steel or iron. In particular, if then the items are clamped together by housing screws together, correspondingly large gaps must allow deformation. The housing screws represent an increased construction cost, thus causing higher costs and also have a non-optimal power flow for the device result.

Object of the invention

The invention is therefore based on the object to design a device for adjusting the rotational angle of a camshaft relative to a crankshaft for an internal combustion engine such that on the one hand, a reduction in mass of the device takes place on the other hand while minimizing the leakage.

Description of the invention

The DE 199 51 390 A1 discloses a device for hydraulic rotation angle adjustment of a shaft relative to a drive wheel, wherein a wave side arranged plate cooperates with the drive wheel or a drive wheel side arranged component for adjusting the rotational angle. The device has at least one ring-shaped formation in the plate and provided on the drive wheel or the component means which cooperate with the formation in such a way that it is subdivided into two separate chambers. In addition, the device is provided with means for selective hydraulic loading of the chambers for adjusting the relative rotational position of the drive wheel and shaft.

According to the invention the object is achieved in a device for an internal combustion engine with the features of the preamble of claim 1, characterized in that essential parts of the stator, in particular its web walls and its inner and outer walls, and optionally the housing with a possibly disposed therein sealing disc produced as chipless Sheet metal parts are formed. Of course, instead of sheet also band can be used, being used in the following sheet as a generic term for sheet or strip.

The solid sintered components as pressure chamber forming units of the drive side are thus replaced by thin-walled sheet metal and Blechumformteile. Thus, because fewer sintered components need to be manufactured, there is a reduction in the machining cost and a reduction in external oil leakage due to the elimination of the porous sintered parts.

In order for the device, despite its lower mass, to have a high degree of rigidity and load capacity, these sheets can be ideally adapted to the load locally along the load directions by means of formations or corresponding profilings, without the need for globally larger wall thicknesses and thus a high mass being taken into account , Compared to a Massereduktion by using light metal such as in DE 101 34 320 A1 proposed, this has the advantage that the thermal expansion coefficient of all components remains the same and thus no leaks due to thermal effects can arise.

The stator consists of inner and outer circumferential walls and web walls. The web walls each connect two ends of adjacent inner and outer circumferentially extending walls and extend substantially radially. For some Statorvarianten it is advantageous if the web walls are not exactly radial, but have a certain angle to the radial or they are not flat, but recesses, for example, to prevent jamming of the wings in their end positions.

Because the stator is made of thin-walled sheet metal, it is not as dimensionally stable as a sintered stator known in the art. It is possible to attach the stator directly to the torque-transmitting component via integral connection possibilities. In order to achieve a comparable bending and compression stiffness as that of the sintered stator, but it can be used in a comprehensive housing him ( FIG. 2a ), with the joining technologies of the forming technology or by general force, form, friction-locking technologies such as knurling, flanging, welding, caulking, riveting, gluing or bent retaining lugs is connected to the drive wheel. The housing then takes over the connection of the stator to the drive wheel as torque-transmitting and radial load-transferable component and the seal. It also prevents vibrations from occurring on the stator due to introduced radial forces.

The housing seals the stator on one end face and forms an end wall there. If the stator walls do not form a right angle to the end wall, the sealing of the pressure chambers is not completely guaranteed. To avoid leakage losses, it is therefore advantageous to arrange a sealing disc immediately in front of the end wall, so that after connecting the end wall with the stator and inserting the rotor with wings perpendicular pressure chambers arise. The stability of the housing can be additionally increased by connecting the sealing disc firmly to the end wall. The sealing disc is preferably profiled from thin-walled sheet metal and adapted to the size and shape of the stator.

The cohesion of the parts stator, housing and sealing disc is ensured by the above-mentioned joining technologies of forming technology. Compared with the axial, non-positive screw connection, compressive stress deformations are reduced; In addition, advantageously no additional component is needed and reduces assembly costs.

It is expedient to form the non-cutting parts made of metal strips. If necessary, as in the case of the stator, the strip must be formed into a ring at one point and then firmly connected, for example by welding. The non-cutting production of the stator and the housing of course does not mean that these parts are not machined, if very high accuracy should be required.

A second way to increase the bending and compressive rigidity of the stator is to form the web walls so that they can transmit radial forces and / or circumferential forces ( FIG. 3a ). The support of the radial chain or belt force can internally between stator and rotor or externally between Camshaft or an extension of the rotor and sprocket or made a combination of both possibilities. It has proved particularly advantageous not to form the web walls exactly radially, but make in a range of 10 ° to 30 ° to the radial, so that the wings touch the radially outer web wall ends in their end positions.

A third embodiment is a tubular stator, the web walls are formed as retracted webs. The remaining, closed ring surface saves the housing. This further reduces the mass. Between the edge and the radially extending walls, the sealing washer can be inserted and then sealed the edge and firmly connected. In this embodiment, the annular surface absorbs the radial forces and prevents the stator from vibrating.

In order to achieve a better formability, the radially extending walls may also be formed as open ends, then being used for storage and sealing in the rotor sliding shoes. The sliding blocks are designed and arranged such that they support the web walls formed as retracted webs against each other. This prevents bending of the web walls.

The spaces located between the web walls, either cavities or cuts, are plastic-injected or sprayed or metal foamed. As a result, the profile of the substantially radially extending web walls is stiffened and a high tightness of the pressure chambers with each other and made safe to the outside.

The wall thickness of the radially extending walls of the stator can be further reduced by preventing the vanes of the rotor from abutting and exerting pressure in their respective end positions against the radially extending walls of the stator. For this purpose, a Verstellwinkelbegrenzung is necessary. This can, for example, via an associated with the rotor element Verstellwinkelbegrenzung that in a corresponding backdrop engages, be realized.

The inventively designed device is thus easier compared to a device of the prior art, requires less cutting work and thus reduces the manufacturing costs and can also do without a resin impregnation or steam treatment of sealing the now no longer required sintered material.

Brief description of the drawings

Figur 1

einen Längsschnitt einer Vorrichtung zur Drehwinkelverstellung, wobei ein spanlos ausgebildeter Stator in einem Außengehäuse eingesetzt ist;

Figur 2

einen Querschnitt durch eine Vorrichtung zur Drehwinkelverstellung,

Figur 3

einen Querschnitt einer zweiten Ausführung eines Stators,

Figur 4a

einen Querschnitt einer dritten Ausführung eines Stators,

Figur 4b

eine perspektivische Ansicht des Stators gemäß Figur 4a,

Figur 5a

einen Querschnitt einer vierten Ausführung eines Stators, dessen äußere Ringfläche geschlossen ist,

Figur 5b

eine perspektivische Ansicht des Stators gemäß Figur 5a,

Figur 6a

eine perspektivische Ansicht auf eine äußere, in Umfangsrichtung verlaufende Wand und nach außen ausgeformte Stegwände einer fünften Ausführung eines Stators

Figur 6b

eine perspektivische Ansicht auf eine äußere, in Umfangsrichtung verlaufende Wand und nach innen ausgeformte Stegwände einer sechsten Ausführung eines Stators mit einem Gleitschuh.

The invention will be explained in more detail with reference to embodiments and shown schematically in the accompanying drawings.
Show it

FIG. 1

a longitudinal section of a device for adjusting the rotational angle, wherein a chipless formed stator is inserted in an outer housing;

FIG. 2

a cross section through a device for adjusting the rotational angle,

FIG. 3

a cross section of a second embodiment of a stator,

FIG. 4a

a cross section of a third embodiment of a stator,

FIG. 4b

a perspective view of the stator according to FIG. 4a .

FIG. 5a

a cross section of a fourth embodiment of a stator whose outer annular surface is closed,

FIG. 5b

a perspective view of the stator according to FIG. 5a .

FIG. 6a

a perspective view of an outer, circumferentially extending wall and outwardly shaped web walls of a fifth embodiment of a stator

FIG. 6b

a perspective view of an outer, circumferentially extending wall and inwardly molded web walls of a sixth embodiment of a stator with a sliding block.

Detailed description of the drawings

From the FIGS. 1 and 2 go the essential parts of a hydraulic device 1 for the rotational angle adjustment of a camshaft 2 with respect to a crankshaft, not shown, which is designed as a hydraulic actuator. This device 1 is driven by a drive wheel 3, which is connected for example by a chain, not shown, with the crankshaft. In essence, the device 1 consists of a fixedly connected to the drive wheel 3 stator 4, which is closed by a front wall 5 and the drive wheel 3 fluid-tight, and a rotatably connected by an axial central screw 21 with the camshaft 2 rotor 6, wherein the rotor is designed as an impeller. The stator 4 of the device 1 forms by web walls 7, 7 ', 7 "and by outer 8, 8', 8" and inner 9, 9 ', 9 ", extending in the circumferential direction walls with the rotor 6 and its wings 10 first pressure chambers 11, 11 ', 11 "and second pressure chambers 12, 12', 12", which, filled with hydraulic fluid, produce an angular displacement between rotor 6 and stator 4. The rotor 6 and the stator 4 are arranged in a housing 13 which surrounds the The first 11, 11 ', 11 "and second 12, 12', 12" pressure chambers are sealed to the outside by means of an element 16, which adjoins the rotor 6 for adjustment angle limiting, which engages in a corresponding link 17, limiting the adjustment range of the Rotor 6, which reduces the burden of the stator 4.

For the purpose of sealing the pressure chambers 11, 11 ', 11 ", 12, 12', 12" is between Housing 13 and stator 4, a sealing washer 14 is inserted, which is adapted to the diameter of the stator 4.

In FIG. 2 are the web walls 7, 7 ', 7 "not exactly formed radially, but at an angle of about 20 °, so that the wings 10 in their end positions, the radially outer ends of the web walls 7, 7', 7" touch. Thus, the bending and compressive rigidity of the stator 4 is increased, and it is possible to transmit radial forces and circumferential forces

FIG. 3 shows a cross section of a second version of a tubular stator 4. It forms by its substantially radially extending web walls 7, 7 ', 7 "and its inner 8, 8', 8" and outer 9, 9 ', 9 ", in Circumferentially extending walls with the rotor 6, not shown in this figure, the first 11, 11 ', 11 "and second 12, 12', 12" pressure chambers .. The stator 4 itself is arranged in a cylindrical housing 13 such that the housing 13 and the outer, circumferentially extending walls 9, 9 ', 9 "touch each other, whereby the rigidity of the stator 4 is increased and vibrations due to radial forces are damped. The rigidity can be further increased by filling the hollow chambers or incisions 15, 15 ', 15 "formed by the housings 13 and stator 4, for example, with metal foam, so that the wings 10 do not jam in the end positions, it is advantageous to radially extending web walls in two parts, such that they have at least a first, radially extending part 20, to which the wings abut and at least one further part.

The FIGS. 4a and 4b show a cross-section and a perspective view of a third embodiment of a stator 4. Compared to in FIG. 2 illustrated embodiment, this third stator 4 is stiffer with respect to a radial force absorption. It is particularly advantageous to set the web walls such that the respective adjacent web walls 7, 7 'and the housing 13 prevent spreading under radial force (self-locking).

The FIGS. 5a and 5b show a cross section and a perspective view The web walls 7, 7 ', 7 "are designed as webs drawn into the stator 4. They form with the walls 8, 8', 8", 9, 9 ', 9 "extending in the circumferential direction A particularly advantageous feature of this design is that the housing 13, with the exception of the end wall 5, can be saved by the remaining, closed annular surface, the circular outer wall 18. As the end wall 5, the sealing disc 14 (FIG. FIG. 1 ), which is used on the front side of the stator 4 and whose edge can be crimped, for example. From the circular outer wall 18 arise by punching, for example, the web walls 7, 7 'which are then bent inwards. The web walls 7, 7 ', 7 "are well deformable by their open ends FIG. 6b may be formed and then sealed with sliding shoes 19.

The Figures 6a and 6b show a perspective view of a part of a fifth and sixth stator 4, the variants of the fifth stator 4 represent. The web walls 7, 7 'are bent once inwards, the other times outwards. These stator variants 4 are therefore inserted into a housing 13. The web walls 7, 7 'are each supported by sliding shoes 19 (FIG. FIG. 6b ) sealed. The latter support the web walls 7, 7 'and prevent deformation due to external radial forces introduced.

In summary, results from the non-cutting produced components, in particular by essential parts of the stator 4, a large mass reduction of the device. A similar rigidity as in the devices of the prior art is achieved by the illustrated embodiments of the stator 4. At the same time, the leakage losses are reduced, as can be dispensed with porous sintered components or a complex steam treatment or resin impregnation.

LIST OF REFERENCE NUMBERS

1

hydraulic device for adjusting the angle of rotation

2

camshaft

3

drive wheel

4

stator

5

bulkhead

6

rotor

7, 7 ', 7 "

web walls

8, 8 ', 8 "

outer, circumferentially extending walls

9,9 ', 9 "

inner, circumferentially extending walls

10

wing

11, 11 ', 11 "

first pressure chambers

12, 12 ', 12 "

second pressure chambers

13

outer casing

14

sealing washer

15, 15 ', 15 "

Hollow chambers or incisions

16

Element for adjustment angle limitation

17

scenery

18

circular outer wall

19

shoe

20

first, radially extending part of the web wall

21

axial central screw

Claims (14)

1. Internal combustion engine having a hydraulic device (1) for rotational angle adjustment of a camshaft (2) relative to a crankshaft, comprising: a rotor (6) which has vanes (10) arranged thereon and is rotationally fixedly connected to the camshaft (2), a stator (4) which is provided at at least one end side with an end wall (5) and has substantially a cylindrical outer contour and is rotationally fixedly connected to a drive wheel (3) which is driven by the crankshaft, with pressure chambers (11, 11', 11", 12, 12', 12") being provided at both sides of the vanes (10), which pressure chambers are delimited in each case by web walls (7, 7', 7") and inner (9, 9', 9") and outer (8, 8', 8") walls, which run in the circumferential direction concentrically with respect to one another, of the stator (4) and can be pressurized with hydraulic fluid or emptied by means of a hydraulic system, with the stator (4), including its web walls (7, 7', 7") and its inner and outer walls (8, 8', 8", 9, 9', 9") which run in the circumferential direction, being formed as a strip part or sheet-metal part produced in a non-cutting process, characterized in that the pressure chambers (11, 11', 11", 12, 12', 12") are closed off at the end side by a circular-ringshaped sealing disc (14) which is formed as a sheet-metal part.
2. Device according to Claim 1, characterized in that the stator (4) is reinforced locally at particularly loaded points, along the loading directions, by mouldings, beads or corresponding profiles.
3. Device according to Claim 1, characterized in that the stator (4) has an outer housing (13) which is preferably tubular and formed as a sheet-metal part and which comprises the web walls (7, 7', 7") and the outer (8, 8', 8") and inner (9, 9', 9") walls in the circumferential direction.
4. Device according to Claim 1, characterized in that the stator (4), housing (13) and drive wheel (3) are fastened to one another by connecting techniques from the field of forming technology, for example knurling, flanging, welding, calking, riveting, adhesive bonding or bent holding lugs.
5. Device according to Claim 1, characterized in that the sealing disc (14) is fixedly connected to the end wall (5) which is formed in one piece with the outer housing (13).
6. Device according to Claim 1, characterized in that an element (16) for adjustment angle limitation is arranged in the rotor (6), which element (16) engages into a corresponding sliding-block guide (17).
7. Device according to Claim 1, characterized in that the stator (4) is composed of alternating outer walls (8, 8', 8") which run in the circumferential direction and inner walls (9, 9', 9") which run in the circumferential direction, which walls are in each case sections of a circular cylinder, with in each case adjacent outer (8, 8', 8") and inner (9, 9', 9") walls which run in the circumferential direction being connected by web walls (7, 7', 7") which, together with a circular rotor (6) which is inserted into the stator and the vanes (10) arranged in said rotor (6), form pressure chambers (11, 11', 11", 12, 12', 12"), and at their sides facing away from the pressure chambers, form cavities or indentations (15, 15', 15").
8. Device according to Claim 7, characterized in that the cavities or indentations (15, 15', 15") are filled with metal foams or are extrusion coated with plastic or filled with plastic by injection moulding.
9. Device according to Claim 7, characterized in that the web walls (7, 7', 7") run or are formed such that, in the end positions, the vanes (10) abut against the web walls (7, 7', 7") either only at their radially outer end, only at their radially inner end or only in a central region.
10. Device according to Claim 7, characterized in that the web walls (7, 7', 7") are formed as webs drawn inward or drawn outward in pairs out of the circumferential wall of an outer cylinder or inner cylinder.
11. Device according to Claim 10, characterized in that the web walls (7, 7', 7") are punched out of the inner or outer circumferential wall of the stator (3) and are bent outward or inward in the radial direction in pairs.
12. Device according to Claim 11, characterized in that the web walls (7, 7', 7") are connected in pairs by a sliding shoe (19) which supports them, and form cavities (15, 15', 15").
13. Device according to Claim 12, characterized in that the cavities (15, 15', 15") are filled with metal foams or are extrusion coated with plastic or filled with plastic by injection moulding.
14. Device according to Claim 7, characterized in that the web walls (7, 7', 7") form an angle of 10° to 30° with respect to the radial, such that the vanes, in their end positions, make contact only with the radially outer ends of the web walls (7, 7',7").

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