DE102012206562A1 - Vane type hydraulic camshaft adjuster for use in internal combustion engine to vary e.g. control times of combustion chamber valves, has chambers in power flow from drive element to output element connected into or disconnected from flow - Google Patents

Abstract

The adjuster (1) has a drive element (2) and an output element (3) rotated relative to each other around a rotational axis (4) by hydraulic working chambers of the adjuster. The output element is arranged concentric to the drive element and coaxial to the rotational axis. The output element is rotationally rigidly connected with a camshaft. An intermediate rotor (5) divides the working chambers into multiple active same-directional pressure chambers (A-D). The pressure chambers in a power flow from the drive element to the output element are connected into or disconnected from the power flow.

Description

Field of the invention

The invention relates to a camshaft adjuster.

Background of the invention

Camshaft adjusters are used in internal combustion engines for varying the timing of the combustion chamber valves. By means of the camshaft adjuster, the phase relation between a crankshaft and a camshaft in a defined angular range, between a maximum early and a maximum late position, can be made variable. Adjusting the timing to the current load and speed reduces fuel consumption and emissions. For this purpose, camshaft adjuster are integrated into the drive train, via which a torque is transmitted from the crankshaft to the camshaft. This drive train may be formed for example as a belt, chain or gear drive.

In a hydraulic camshaft adjuster, the output element and the drive element form one or more pairs of mutually acting pressure chambers, which can be acted upon by hydraulic fluid. The drive element and the output element are arranged coaxially. By the targeted filling and emptying of individual pressure chambers, a relative movement between the drive element and the output element is generated. Optionally, a rotatably acting between the drive element and the driven element spring is provided, which urges the drive element relative to the output element in an advantageous direction. This advantage direction can be the same or opposite to the direction of rotation.

One type of hydraulic phaser is the vane phaser. The vane cell adjuster comprises a stator, a rotor and a drive wheel with an external toothing. The rotor is designed as a driven element usually rotatably connected to the camshaft. The drive element includes the stator and the drive wheel. The stator and the drive wheel are rotatably connected to each other or alternatively formed integrally with each other. The rotor is coaxial with the stator and located inside the stator. The rotor and the stator are characterized by their, radially extending wings, oppositely acting oil chambers, which are acted upon by oil pressure and allow relative rotation between the stator and the rotor. The wings are either formed integrally with the rotor or the stator or arranged as "inserted wings" in designated grooves of the rotor or the stator. Furthermore, the vane cell adjusters have various sealing lids. The stator and the sealing lids are secured together via several screw connections.

Hydraulic camshaft adjusters, in particular in vane-type construction, are known from the state of the art, which have a fixed pressure ratio, ie. H. the pressure-effective surface of the wing remains constant and thus a force for adjustment is impressed on the wings, which follows the pressure curve of the oil pump, as a function of speed, or correlated. Particularly in the case of non-variable oil pumps, a low oil pressure is present in the low rpm range of the internal combustion engine, whereas a high oil pressure is therefore available in the high rpm range. As a result, due to the constant area of the vanes within a given speed range of the entire engine speed range, the vane phasers are in the optimum operating range and have a deficiency in the remaining speed range, particularly the low speed range. To approximate the operating range of the camshaft adjuster to the entire speed range of the internal combustion engine, variable oil pumps can be used. These are however complicated and expensive. An alternative is the adaptation of the camshaft adjuster to the lower speed range of the internal combustion engine, but this potential is unused in the upper speed range of the internal combustion engine.

Summary of the invention

The object of the invention is to provide a camshaft adjuster, which has a variable pressure ratio.

According to the invention, this object is solved by the features of claim 1.

The object is achieved by a camshaft adjuster with exactly one drive element and exactly one output element, wherein the exactly one output element with only one camshaft is rotatably connected and exactly one drive element with a crankshaft rotatably connected, wherein the output element concentric with the drive element and coaxial with the axis of rotation Camshaft adjuster is arranged, wherein the drive element and the driven element can be rotated relative to each other about the axis of rotation, the relative rotation by means of hydraulic working chambers of the camshaft adjuster is achieved in that an intermediate rotor is provided which the hydraulic working chambers in several directionally effective Separates pressure chambers that can be switched independently of each other in the power flow from the drive element to the output element or out of the power flow.

This ensures that at least two speed ranges for the camshaft adjuster are provided as an operating range, whereby the camshaft adjuster can be optimally operated in a significantly larger speed range. By means of the camshaft adjuster according to the invention, the camshaft can be adjusted to the crankshaft and thus the control times of this camshaft in at least two rotational speed ranges efficiently, with regard to the oil consumption. The intermediate rotor is not connected to another camshaft, but is in the context of the invention in the power flow for adjustment between the exact one crankshaft and the exact camshaft effective.

In one embodiment of the invention, the intermediate rotor, the drive element and the driven element radially directed wings, which divide the working chambers, wherein the intermediate rotor is arranged radially between the drive element and the driven element and so an inner ring of working chambers with a plurality of directionally effective pressure chambers and a outer ring of working chambers is formed with a plurality of directionally effective pressure chambers.

The inner ring of working chambers thus has a plurality of directionally effective pressure chambers, which are provided for the one adjustment and equally, the inner ring of working chamber also has a plurality of directionally effective pressure chambers, which are provided for the opposite adjustment.

The outer ring of working chambers thus has a plurality of directionally effective pressure chambers, which are provided for the one adjustment and equally, the outer ring of working chamber also has a plurality of directionally effective pressure chambers, which are provided for the opposite adjustment.

Advantageously, the camshaft adjuster at low speeds, for. B. at engine start, and thus are operated reliably even at low oil pressures first with the inner ring of working chambers, whereby a first adjustment is available. If the oil pressure continues to rise, the outer ring is additionally used by working chambers, which not only makes it possible to influence the adjustment speed, but also extends the first adjustment range by a second adjustment range.

In an alternative embodiment of the invention, the reversing of the adjustment, between the outer ring of working chambers and the inner ring of working chambers switched so that the pressure chambers of the inner or the outer ring in an adjustment and the pressure chambers of the other ring in the other adjustment is effective.

Thus, the directionally effective pressure chambers of the outer ring can be acted upon in a first circumferential direction with oil pressure and the desired adjustment in the opposite, second circumferential direction, the corresponding directionally effective pressure chambers of the inner ring are used. Thus, a Verstellrichtungswechsel can be performed quickly and emptied to be emptied pressure chambers of the outer ring during the adjustment operation of the inner ring. As a result, the hydraulic resistance of the pressure chambers to be emptied, which acts counter to the adjustment direction and is caused by the throttle of the outflow, no longer occurs and no longer counteracts the adjustment movement, as a result of which the adjustment speed, in particular when the direction changes, is increased. Contrary to a reversal of direction with a prior art known Flügelzellenversteller advantageously occurs according to the invention no loss of time in the switching of the filling of the oppositely acting pressure chamber of the same ring.

If necessary, the Verstellrichtungsumkehr can already be completed, d. H. the camshaft is already adjusted relative to the crankshaft in the following opposite direction; Nevertheless, the outer or inner ring of working chambers performs an adjustment in the former, the current adjustment direction preceding adjustment. Here, the filling of those directionally effective pressure chambers, which are effective for adjustment in this following, opposite direction, faster than the emptying of those directionally effective pressure chambers, which were effective for the adjustment in the former, previous adjustment.

In an advantageous embodiment, the intermediate rotor on a locking mechanism which can rotatably couple the intermediate rotor with the drive element. Advantageously, the variable pressure ratio of the camshaft adjuster is thus switchable by mechanical locking between the intermediate rotor and the drive element. The locking mechanism is preferably actuated by oil pressure. Alternatively, with this locking mechanism of the intermediate rotor, the angular position between the intermediate rotor and the driven element can be fixed.

In one embodiment of the invention, the output element has a locking mechanism which can couple the output element with the drive element in a rotationally fixed manner. Advantageously, the variable pressure ratio of the camshaft adjuster is thus switchable by mechanical locking between the output element and the drive element. The locking mechanism is preferably actuated by oil pressure. Alternatively, with this locking mechanism of the output element, the angular position between the output element and the intermediate rotor can be fixed.

In one embodiment of the invention, the intermediate rotor and the driven element each have a locking mechanism to rotatably couple the intermediate rotor and / or the driven element to the drive element.

The locking operations of several locking mechanisms can be performed independently of each other, depending on each other or staggered. The locking mechanism is preferably actuated by oil pressure.

Alternatively, the aforesaid mechanical interlocking mechanisms can replace or supplement the mechanical interlocking mechanisms mentioned above, the positions of the wings in the working chambers of the inner and / or outer ring are hydraulically clamped, whereby the angular position between the respective aforementioned components responsible for the adjustment movement of the camshaft adjuster are fixed.

In an advantageous embodiment of the invention, the intermediate rotor on oil passages to direct the oil from the inner ring to the outer ring. Advantageously, as a result of the arrangement of radial oil passages on the intermediate rotor of the outer ring are hydraulically connected to the inner ring, so that for example the wings of the output element initially obscure a radial oil passage, but upon enlargement of the pressure chamber of the inner ring, for example, in the movement of a wing of the Output elements of a starting position in the direction of its end position, this radial oil passage from the wing is released or opened, so that the oil from this pressure chamber in the directionally effective pressure chamber of the outer ring can flow. This principle can alternatively be implemented by a wing of the intermediate rotor or the drive element.

Alternatively, the oil passages can be designed to supply the pressure chambers from the output element and / or from the drive element. The oil passages for supplying the pressure chambers may also be formed by one side cover or a plurality of side covers. Advantageously, the pressure chambers of the outer ring can thus be filled or emptied hydraulically independently of one another by the pressure chambers of the inner ring. Likewise, the pressure chambers of the inner or outer ring which act in the same direction can be filled or emptied hydraulically independently of one another by the oppositely directed pressure chambers of the respective ring.

In a preferred embodiment of the invention, the number of working chambers of the inner ring is different from the number of working chambers of the outer ring.

In a first preferred embodiment of this embodiment of the invention, the number of working chambers of the inner ring may be smaller than the number of working chambers of the outer ring. Advantageously, to fill the working chambers or their directionally equal effective pressure chambers for adjustment in one direction less oil volume is necessary, which is low especially at engine start the oil consumption of the camshaft adjuster. Another advantage is that fewer oil passages to the working chambers of the inner ring must be provided, thereby reducing the manufacturing cost.

In a second preferred embodiment of this embodiment of the invention, the number of working chambers of the inner ring may be greater than the number of working chambers of the outer ring. Advantageously, to fill the working chambers or their directionally equal effective pressure chambers for adjustment in one direction less oil volume is necessary, which is low especially at engine start the oil consumption of the camshaft adjuster.

In a third preferred embodiment of this embodiment of the invention, the number of working chambers of the inner ring may be equal to the number of working chambers of the outer ring.

These three preferred embodiments may advantageously be combined with the following paragraphs on variation in the design of the pressure surface of the vanes to control the oil consumption of the camshaft phaser to the predetermined supply oil volume, which is dependent on the engine speed, in or in the desired operating condition of the camshaft adjuster. As a pressure surface, the skilled person understands the effective pressure for the adjustment surface or the projection of a boundary wall of the wing. In particular, it is characteristic of the definition of the printing surface that the size of the printing surface for adjustment in the Manufacture of the wing is fixed and not due to the movement of the wing, eg. When moving out of an end stop position or during operation of the camshaft adjuster changes. The boundary wall of the wing, which limits the pressure chamber, may be curved, so that, for example, a wing is provided with a convex or a concave shape. Alternatively, the boundary wall of at least one side of the wing may be a plane.

In an advantageous embodiment, the pressure surfaces of at least one outwardly-oriented wing of the intermediate rotor and at least one inwardly-oriented wing of the intermediate rotor are formed differently large.

The wings for the outer ring of working chambers are provided with a pressure surface which different from the pressure surface of the wings for the inner ring of working chambers in its size or in its surface area, whereupon the oil pressure acts so that an adjustment takes place. The variations of the outwardly oriented and / or the inwardly oriented wings of the intermediate rotor, in particular their pressure surfaces, may be in their radial heights and / or axial widths. The pressure surfaces of the corresponding vanes of the drive element and / or of the drive element are adapted to the pressure surfaces of the vanes of the intermediate rotor.

In an alternative embodiment of the invention, the areas of the pressure surfaces of the radially outwardly extending vanes and the radially inwardly extending vanes may be the same size. Even at different heights and / or widths of the radially outwardly extending wings and the radially inwardly extending wings, an equal area of the pressure surfaces can be formed. Advantageously, the space for the working chambers of the inner ring and the working chambers of the outer ring can be adapted to the space specified by the internal combustion engine.

In a further embodiment of the invention, the drive element is mounted on the intermediate rotor and the intermediate rotor on the driven element. The power flow for adjustment and the bearing force is transmitted from the drive element to the intermediate rotor on the output element and consequently on the camshaft. Advantageously, such a camshaft adjuster requires little installation space in the axial direction. Alternatively, the drive element can be mounted on the camshaft. The bearing force, starting from the timing drive, is thus transmitted directly to the camshaft without requiring the intermediate rotor for this purpose. Thus, the intermediate rotor is loaded almost exclusively with force for the adjustment, starting from the oil pressure and does not have to overcome the friction, which is impressed by the bearing force, starting from the tensioned control drive. However, a load bearing, axial bearing width must be provided for the bearing of the drive element.

The inventive arrangement of an intermediate rotor in a phaser a variable pressure ratio is achieved. It can now be the oil consumption of the camshaft adjuster to the supply oil volume, which is dependent on the speed of the internal combustion engine, adjusted.

Brief description of the drawings

Embodiments of the invention are illustrated in the figures.

It shows:

1 a camshaft adjuster with an intermediate rotor.

Detailed description of the drawings

The basic structure and function of a conventional camshaft adjuster 1 is well known. In the following, the special feature of this exemplary embodiment, namely a camshaft adjuster with an intermediate rotor, is discussed.

In 1 is a hydraulic phaser 1 shown in vane construction in a front view with a clear view of his interior, which is a driving element 2 , an output element 3 and an intermediate rotor 5 having. The three components are coaxial with the axis of rotation 4 of the camshaft adjuster 1 arranged. The drive element 2 , the output element 3 and the intermediate rotor 5 share with their wings 6 the hydraulic working chambers in several, equally effective pressure chambers A, C & B, D, from. The pressure chambers A, B, C, D are acted upon by oil pressure to a relative rotation about the axis of rotation 4 of the camshaft adjuster 1 between the drive element 2 , the output element 3 and also the intermediate rotor 5 to reach.

The oil to the pressure chambers A, B is via oil channels 13 . 14 of the output element 3 each added or removed. The oil to the pressure chambers C, D is via oil channels 11 . 12 the intermediate rotor each added or removed. The drive element 2 has a rotatably arranged toothing 15 , In this embodiment, the toothing 15 suitable for a not shown, known from the prior art, chain drive and in one piece with the drive element 2 educated. The drive element 2 is usually made up of several components, for example. With other cover elements, constructed, wherein the components are braced together by screws for the production of the component composite. For these screws are the axial holes 16 intended.

The output element 3 can be rotatably connected to a camshaft, not shown. Through the pressure chambers A, B, a relative rotation of the output element 3 to the intermediate rotor 5 and through the pressure chambers C, D from the intermediate rotor 5 to the drive element 2 be generated. By adjusting the angular position between the drive element 2 and output element 3 and the interposed intermediate rotor 5 Thus, a change in the timing on the adjustment of the phase position between exactly one crankshaft and exactly one camshaft is achieved. The intermediate rotor 5 This is not connected to another camshaft, but is in the adjustment of the camshaft adjuster 1 as an intermediate element in the power flow between the drive element 2 and the output element 3 intended.

In 1 For reasons of clarity, a few segments of the camshaft adjuster are used 1 described. The characteristics of the segments can be found in the camshaft adjuster 1 depending on the number of wings 17 . 18 and 6 the components drive element 2 , Output element 3 and intermediate rotor 5 multiply by the circumference. So has the drive element 2 five radially inwardly directed wings 18 , the output element 3 five radially outwardly directed wings 17 and the intermediate rotor 5 radially outwardly and radially inwardly circumferentially alternating vanes 6 , The wings 6 . 17 and 18 Divide the pressure chambers A, B, C, D, which are each five times available.

The drive element 2 and intermediate rotor 5 form the outer ring of working chambers 8th , whereas the output element 3 and the intermediate rotor 5 the inner ring of working chambers 7 form. The outer ring of working chambers 8th includes the pressure chambers C, which are effective in one direction of adjustment, counterclockwise here, the same direction. In addition, the outer ring includes working chambers 8th also the opposite to the pressure chambers C acting pressure chambers D, which are effective in the other adjustment direction, here in a clockwise direction. The inner ring of working chambers 7 includes the pressure chambers A, which are effective in one direction of adjustment, counterclockwise here, the same direction. In addition, the inner ring includes working chambers 7 also the opposite to the pressure chambers A acting pressure chambers B, which are effective in the other adjustment direction, here in a clockwise direction.

A grand piano 17 of the output element 3 has a locking mechanism 10 and a grand piano 6 of the intermediate rotor 5 , here it is a wing 6 which extends radially outward has the locking mechanism 9 , The locking mechanisms 9 . 10 work according to the piston-spring principle, known from the prior art. Through the locking mechanisms 9 . 10 Optionally, the output element 3 with the drive element 2 and / or the intermediate rotor 5 with the drive element 2 rotatably coupled. For this purpose, the angular positions in the end positions of the wings offer 17 and 6 at and / or their angular position between the end positions of the wings 17 and 6 , especially in the middle position.

The oil channels 13 . 14 of the output element 3 are designed as radial bores. The oil channel 13 communicates with the pressure chamber A and the oil passage 14 communicates with the pressure chamber B. The oil channels 11 . 12 of the intermediate rotor 5 are as at an end face of the intermediate rotor 5 arranged grooves formed. The oil channel 11 communicates with the pressure chamber A & C and the oil channel 12 communicates with the pressure chamber B & D. Through the oil channels 11 . 12 of the intermediate rotor 5 For example, the oil can be supplied to and / or removed from the pressure chambers A and B to the respective pressure chambers C and D.

The structure of this embodiment results in the following operation:
First, both are locking mechanisms 9 and 10 pressure-locked and fix the illustrated angular position between the output element 3 , the intermediate rotor 5 and the drive element 2 , wherein the end stop positions between the wings 17 and 6 such as 6 and 18 are formed.

The locking mechanism 10 is now unlocked, with the locking mechanism 9 remains locked. To pressurize the pressure chamber A, the oil flows through the oil passage 13 in the pressure chamber A, wherein at the same time the oppositely acting pressure chamber B "connected to the tank" is. This is followed by a relative adjustment about a first angle range between the intermediate rotor 5 and the output element 3 and thus also an adjustment of the timing of the combustion chamber valves. Part of the oil also flows into the pressure chamber C, but its volume due to the locked locking mechanism 9 can not enlarge. Ideally, the use of the outer ring of working chambers 8th first the locking mechanism 10 again in the desired position of the grand piano 17 , for example, in its other end stop position with the adjacent wing 6 , locked. Will now be the locking mechanism 9 unlocked, so further oil flows from the pressurized oil pressure chamber A through the oil passage 11 in the pressure chamber C. Consequently, the pressure chamber C increases, whereby the first angle range is followed by a second angle range for adjustment.

For a clockwise adjustment, the procedure is analogous to the previously described mode of operation.

LIST OF REFERENCE NUMBERS

1

Phaser

2

driving element

3

driving element

4

axis of rotation

5

between the rotor

6

wing

7

inner ring of working chambers

8th

outer ring of working chambers

9

locking mechanism

10

locking mechanism

11

oil passage

12

oil passage

13

oil passage

14

oil passage

15

gearing

16

drilling

17

wing

18

wing

A

pressure chamber

B

pressure chamber

C

pressure chamber

D

pressure chamber

Claims (10)

Camshaft adjuster ( 1 ) with - exactly one drive element ( 2 ) and exactly one output element ( 3 ), - which is exactly one output element ( 3 ) with only one camshaft rotatably connected and the exactly one drive element ( 2 ) is rotatably connected to a crankshaft, - wherein the output element ( 3 ) concentric with the drive element ( 2 ) and coaxial with the axis of rotation ( 4 ) of the camshaft adjuster ( 1 ) is arranged, - wherein the drive element ( 2 ) and the output element ( 3 ) relative to each other about the axis of rotation ( 4 ), wherein the relative rotation by means of hydraulic working chambers of the camshaft adjuster ( 1 ), characterized in that an intermediate rotor ( 5 ) is provided, which divides the hydraulic working chambers into a plurality of directionally effective pressure chambers (A, B, C, D), in the power flow from the drive element ( 2 ) to the output element ( 3 ) or can be switched out of the power flow. Camshaft adjuster ( 1 ) according to claim 1, characterized in that the intermediate rotor ( 5 ), the drive element ( 2 ) and the output element ( 3 ) radially directed wings ( 6 ), which divide the pressure chambers (A, B, C, D) and the intermediate rotor ( 5 ) radially between the drive element ( 2 ) and the output element ( 3 ) and so an inner ring of working chambers ( 7 ) with a plurality of directionally effective pressure chambers (A, B) and an outer ring of working chambers ( 8th ) is formed with a plurality of directionally effective pressure chambers (C, D). Camshaft adjuster ( 1 ) according to claim 2, characterized in that for reversing the adjustment direction between the outer ring of working chambers ( 8th ) and the inner ring of working chambers ( 7 ) is switched so that the pressure chambers (A, B, C, D) of the inner or the outer ring of working chambers ( 7 . 8th ) in one adjustment direction and the pressure chambers (A, B, C, D) of the respective other ring of working chambers ( 7 . 8th ) is effective in the other adjustment direction. Camshaft adjuster ( 1 ) according to claim 1 or 2, characterized in that the intermediate rotor ( 5 ) a locking mechanism ( 9 ), which the intermediate rotor ( 5 ) with the drive element ( 2 ) can couple rotatably. Camshaft adjuster ( 1 ) according to claim 1 or 2, characterized in that the output element ( 3 ) a locking mechanism ( 10 ), which the output element ( 3 ) with the drive element ( 2 ) can couple rotatably. Camshaft adjuster ( 1 ) according to claim 1 or 2, characterized in that the intermediate rotor ( 5 ) and the output element ( 3 ) each have a locking mechanism ( 9 . 10 ) to the intermediate rotor ( 5 ) and / or the output element ( 3 ) with the drive element ( 2 ) rotatably to couple. Camshaft adjuster ( 1 ) according to claim 2, characterized in that the intermediate rotor ( 5 ) Oil channels ( 11 . 12 ) to remove the oil from the inner ring of working chambers ( 7 ) to the outer ring of working chambers ( 8th ). Camshaft adjuster ( 1 ) according to claim 2, characterized in that the number of working chambers of the inner ring ( 7 ) of the number of working chambers of the outer ring ( 8th ) is different. Camshaft adjuster ( 1 ) according to claim 2, characterized in that the pressure surface of a outwardly oriented wing ( 6 ) of the intermediate rotor ( 5 ) and the pressure surface of an inwardly oriented wing ( 6 ) of the intermediate rotor ( 5 ) are different in size. Camshaft adjuster ( 1 ) one of the preceding claims, characterized in that the drive element ( 2 ) on the intermediate rotor ( 5 ) and the intermediate rotor ( 5 ) on the drive element ( 3 ) is stored.

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