WO2018046529A1

WO2018046529A1 - Variable camshaft control means

Info

Publication number: WO2018046529A1
Application number: PCT/EP2017/072320
Authority: WO
Inventors: Tonio-Erik Schultze; Christine Landsberg; Robert Hermann
Original assignee: Volkswagen Aktiengesellschaft
Priority date: 2016-09-08
Filing date: 2017-09-06
Publication date: 2018-03-15
Also published as: EP3510258A1; DE102016217146A1; EP3510258B1

Abstract

The invention relates to a variable camshaft control means (10) having an externally toothed camshaft (12), an internally toothed cam part (14), wherein the cam part (14) is mounted axially displaceably on the camshaft (12), an intermediate space (22) which is arranged between the camshaft (12) and the cam part (14) in a region of an external toothing system of the camshaft (12) and an internal toothing system of the cam part (14), and a lubricant feed device (20) for guiding lubricant into the intermediate space (22). Here, the lubricant feed device (20) has a passage (16a, 16b, 16c, 16d) which extends through the cam part (14), wherein the passage (16a, 16b, 16c, 16d) begins in a lubricant collecting region (18) for mounting the cam part (14) and ends in the intermediate space (22).

Description

description

Variable camshaft control

The invention relates to a variable camshaft control according to the preamble of patent claim 1.

Variable camshaft timing (or variable valve timing) refers to a camshaft timing device for timing control valve timing

Four-stroke engines, such as Petrol or diesel engines to change during operation.

Such a variable camshaft controller has an internally toothed cam piece which is guided over an externally toothed camshaft. In order for a displacement of the cam piece on the camshaft is possible during engine operation, a certain

Minimum amount of play, the so-called backlash, be given between the teeth of these two components. This game provides for a system change of a cam as a result of a change of torque direction in the valve actuation on a roller cam follower for a turnover of the teeth. A turnover impulse at

Turnover increases exponentially to the backlash and is perceived by motor vehicle drivers as "tacker noise." Due to the technical limitations of manufacturing processes, the backlash can not be reduced sufficiently.

For large backlash-related manufacturing problems, a gearing design with a transition pairing is usually selected, requiring manual assembly or costly classifying. There are always parts that can not be put down.

The invention has for its object to provide a camshaft control in which the noise is reduced when turning the teeth.

This object is achieved by a variable camshaft control of the o.g. Art solved with the features characterized in claim 1. Advantageous embodiments of the invention are described in the further claims.

For this purpose, with a variable camshaft control o.g. Type according to the invention a

A lubricant supply means for guiding lubricant provided in a space between the camshaft and the cam piece. There causes the penetrating into the gap lubricant

Lubricant damping, which reduces in particular the acoustic envelope pulses. Thus, a reduction of structure-borne noise pulses by 40% to 50% can be achieved. At the same time a much softer sound characteristic can be achieved, and the radiation in the airborne sound is significantly reduced. In addition, the wear can be significantly reduced in this way, especially on a ball spring package for axially locking the cam pieces. This further allows the camshaft and cam piece to have a greater backlash, i.e. each produce with larger manufacturing tolerances. Thus, a manual assembly with toothing design can be dispensed with, and an automatic production with a corresponding joining system is possible.

The gap is located between the camshaft and the cam piece in a region of an external toothing of the camshaft and an internal toothing of the camshaft

Cam piece.

The lubricant supply means has a passage extending through the cam piece, the passage starting in a lubricant collection area for supporting the cam piece and in the space between the camshaft and the camshaft

Cam piece ends. This has the advantage that residual lubricant from a radial bearing for supporting the camshaft directly to the toothing between the camshaft and the

Cam piece are guided in the intermediate space. In addition, it may also be provided to guide lubricant through a passage in the camshaft in the intermediate space.

According to one embodiment, the passage begins in an undercut of a

Radial bearing surface. The undercut is located at an outer edge of the radial bearing surface. Under an undercut according to DIN 509 a "Abtragung on a

rotationally symmetrical inner edge with a certain shape and specified dimensions, which gives both the tool used during production and the adjoining part during assembly the necessary freedom. "Thus, the undercut is used to create free spaces, which are used as exit zones in the production of tools such As a functional element, the undercut on assemblies / assemblies is required to ensure the flush fitting of counterparts, if no sufficiently large chamfers, radii or curves can be fitted to these counterparts, thus starting the passage immediately the point at which residual lubricant escapes from the radial bearing, so that the escaping residual lubricant can be used particularly effectively in the

Verzahnungszwischenraum be performed without having to remove additional pressure oil from the oil circuit of the engine. According to a further embodiment, the passage begins in a radial bearing surface. Thus, the passage can be made easier and the residual lubricant from the

Guide the radial bearing surface more easily into the gap.

According to another embodiment, the passage is at an angle of .mu.m

Essentially 30 ° to 90 ° to the extension axis (longitudinal axis) of the camshaft. In this case, the passage can, on the one hand, be manufactured particularly easily, while on the other hand, the passage can be made, in particular, from an undercut to particularly critical areas in the production line

Extend clearance and there cause directly a lubricant damping.

According to a further embodiment, the passage extends in the radial direction through the cam piece. The cam piece may e.g. have a substantially cylinder jacket-shaped or hollow cylindrical basic shape with an outer surface and an inner surface. The passage then begins at the outer surface and ends at the inner surface. With respect to the substantially cylinder jacket-shaped or hollow cylindrical basic shape, the passage extends in the radial direction. The term "radial direction" is understood to mean a direction which extends essentially radially inward or outward, but does not necessarily run at right angles to the extension axis (longitudinal axis) of the camshaft not necessarily straight, but may also have bow sections or kinks.

According to another embodiment, the lubricant supply means at least one bore extending through the camshaft, wherein preferably the

Camshaft is a hollow shaft and the at least one bore extends in the radial direction through the camshaft. The lubrication can therefore also be done by a hole in the external gear camshaft.

The lubricant supply device can be designed for pressureless guidance of lubricant in the intermediate space. Thus, no work is done by a lubricant pump to remove lubricant, e.g. to promote through the passage. Therefore, the

Energy consumption of the lubricant pump not increased. Alternatively, e.g. the

Lubricant supply means be adapted to effect an active lubrication of the toothing between the camshaft and the cam piece, that is, lubricant, such as oil, conveyed under pressure into the intermediate space. Furthermore, an internal combustion engine with such a variable camshaft control belongs to the invention.

The invention will be explained in more detail below with reference to the drawings. These show in

1 is a schematic sectional view of a first embodiment of the invention,

Fig. 2 is a schematic sectional view of a second embodiment of the invention, and

Fig. 3 is a schematic sectional view of another embodiment of the invention. Reference is first made to Fig. 1 reference.

Shown is a variable camshaft controller 10 for an internal combustion engine, such as an engine. a four-stroke engine, such as a gasoline or diesel engine. The variable

Camshaft control 10 allows the timing of a valve timing of the

Change internal combustion engine during operation.

In the present exemplary embodiment, the variable camshaft control 10 has an externally toothed camshaft 12 and an internally toothed cam piece 14. The

Cam piece 14 is mounted axially displaceably on the camshaft 12 in the direction of the extension axis (longitudinal axis) of the camshaft 12.

In order to enable a displacement of the cam piece 14 on the camshaft 12, a certain minimum amount of play, the so-called backlash, between the

Gearing of the cam piece 14 and the toothing of the camshaft 12 given or required. In the present embodiment, the backlash is in a range of e.g. 0.65 mm to 0.7 mm.

A radial bearing for rotatably supporting the cam piece 14 has a supply line through which lubricant, e.g. Oil is supplied to a circumferential annular gap of the radial bearing to cause lubrication of the bearing point of the cam piece 14.

Furthermore, a lubricant supply device 20 is provided, with a

Lubricant damping can be achieved, in particular the acoustic

Envelope pulses reduced, as will be explained in detail later. The lubricant supply device 20 has four in the present embodiment

Passages 16a, 16b, 16c, 16d, each extending through the cam piece 14 in a substantially radial direction. Furthermore, the cam piece 14 in the present

Embodiment, a substantially cylinder jacket-shaped or hollow cylindrical basic shape with an outer surface and an inner surface. The four connect

Passages 16a, 16b, 16c, 16d, the outer surface of the cam piece 14 with the inner surface of the cam piece 14. With respect to the substantially cylinder jacket or

hollow cylindrical basic shape of the cam piece 14, the passages 16a, 16b, 16c, 16d extend at least with a directional component in the radial direction. Thus, the four passages 16 a, 16 b, 16 c, 16 d provide a flow direction with a direction component in the radial direction and a direction component in the axial direction of the extension axis of the camshaft 14.

The passages 16a and 16c shown in Fig. 1 on one side and 16b and 16d on the other side are arranged in the circumferential direction of the cam piece 14 equally spaced from each other. It can be distributed over the circumference also provided more than two passes. Furthermore, the two left-hand passages 16a and 16c in FIG. 1 are arranged in the direction of extension of the camshaft 12 at a distance from the two right-hand passages 16b and 16d in FIG. In addition, the passages 16a, 16b and 16c, 16d can also be arranged offset from each other in the circumferential direction.

The four passages 16a, 16b, 16c, 16d begin in a lubricant collecting area 18 and terminate in an approximately cylindrical space 22 between the camshaft 12 and the cam piece 14. In the present embodiment, the

Lubricant collection area 18 in the extension direction (longitudinal axis) of the camshaft 12 in series one behind the other arranged a circumferential, first, left in Fig. 1, left undercut 24a and a circumferential, second, in Fig. 1 right undercut 24b. The undercuts define a radial bearing surface 26 in the axial direction.

The gap 22 is bounded on the one hand by the inner surface of the cam piece 14. In the lubricant collecting area 18, lubricant leaking from the radial bearing (not shown) collects. This can be achieved by the four passages 16a, 16b, 16c, 16d of the

Grease collection area 18 enter the gap 22. On the other hand, the clearance 22 is limited by the outer surface of the camshaft 12.

The lubricant collecting area 18 may be located between the radial bearing surface 26 and the radial bearing. It is provided that the passages 16a, 16b, 16c, 16d are formed for the non-pressurized guidance exiting from the radial bearing lubricant in the gap 22, so that from a lubricant pump (not shown) no additional work must be done to lubricant through the To promote passages 16a, 16b, 16c, 16d.

In the exemplary embodiment shown in FIG. 1, the passages 16a, 16b, 16c, 16d respectively start in the relief grooves 24a, 24b and then extend at an angle of approximately 45 ° to the extension axis of the camshaft 12 rectilinearly up to the gap 22. The passages 16a, 16b, 16c, 16d thus each begin directly at the point where lubricant exits the radial bearing.

Reference is now made to FIG. 2.

The camshaft control 10 shown in FIG. 2 differs from the camshaft control 10 illustrated in FIG. 1 in that the lubricant supply device 20 has two passages 16a, 16b which respectively start in the radial bearing surface 26 and at an angle of substantially 90 ° to the extension axis the camshaft 12 extend. In other words, the two passages 16a, 16b start outside the undercuts 24a, 24b and have a radial orientation without an axial component.

In the present exemplary embodiment, the two passages 16a, 16b are arranged in the axial direction of the extension axis of the camshaft 12 at a distance of approximately 10 mm to approximately 25 mm, preferably with a spacing of 12 mm or 18 mm.

The arrangement and the course of the passages 16a, 16b, in comparison with the first embodiment shown in FIG. 1, make it easier to manufacture. The radial bearing surface 26 thereby provides a contact region between the radial bearing, not shown, and the

Outer surface of the cam piece 14. The radial bearing surface 26 extends in the present embodiment, the width of the radial bearing in the direction of extension of the camshaft 12th

In operation, lubricant is delivered from the lubricant pump through the supply line to the annular gap. Lubricant then exits from the radial bearing and passes without pressure through the four passages 16a, 16b, 16c, 16d or two passages 16a, 16b in the

Gap 22.

There causes the penetrated into the gap 22 lubricant a

Lubricant damping, which significantly reduces the turnover pulses. This also allows the Camshaft 12 and the cam piece 14 to produce a larger Verdrehflankenspiel comprising, ie produce these parts with respect to their interlocking teeth each with larger manufacturing tolerances. So can on a hand assembly with

Verzahnungsauslegung be waived, and it is an automatic production with a corresponding joining plant allows.

A third embodiment of the invention is shown in Fig. 3, which partially illustrates a longitudinal section through a camshaft control. The one section, here longitudinal section, characteristic hatching are omitted in this case for the sake of clarity.

According to the third exemplary embodiment, the lubricant supply device 20 has at least one bore 28 extending through the camshaft 12. The camshaft 12 is at least in this embodiment, a hollow shaft, wherein the at least one bore 28 extends in the radial direction through the camshaft 12. According to one

preferred embodiment, the bore 28 extends diametrically through the

Camshaft 12. The bore 28 thus extends from an opening provided in the camshaft 12 inner bore 30 in the radial direction of the camshaft to the gap 22 between the camshaft 12 and the cam piece 14, as indicated in Fig. 3

Finally, the invention is also applicable to an internal combustion engine with a variable

Camshaft control directed, as indicated in the claims.

For a camshaft control is provided in which the noise is significantly reduced when turning the teeth.

Reference number list

variable camshaft control

camshaft

cam piece

a passage

b passage

c passage

d passage

Grease collection area

lubricant delivering

gap

a underdog

b Undercut

Radial bearing surface

drilling

internal bore

Claims

Patent phrases

1. Variable camshaft control (10) with

an externally toothed camshaft (12),

an internally toothed cam piece (14), the cam piece (14) being axially

slidably mounted on the camshaft (12),

a clearance (22) formed between the camshaft (12) and the cam piece (14) in a region of an outer toothing of the camshaft (12) and a

Internal toothing of the cam piece (14) is arranged, and

a lubricant supply means (20) for guiding lubricant in the

Gap (22),

characterized in that the lubricant supply means (20) has a passage (16a, 16b, 16c, 16d) extending through the cam piece (14), the passage (16a, 16b, 16c, 16d) being located in a lubricant collection area (18) for storage of the cam piece (14) begins and ends in the intermediate space (22).

2. Variable camshaft control (10) according to claim 1, characterized in that the passage (16a, 16b, 16c, 16d) in a relief groove (24a, 24b) of a radial bearing surface (26) begins, wherein the undercut (24a, 24b) on an outer edge of the

Radial bearing surface (26) is located.

3. Variable camshaft control (10) according to claim 1, characterized in that the passage (16a, 16b, 16c, 16d) in a radial bearing surface (26) begins.

4. Variable camshaft control (10) according to claim 1, 2 or 3, characterized

characterized in that the passage (16a, 16b, 16c, 16d) extends at an angle of substantially 30 ° to 90 ° to the extension axis of the camshaft (12).

5. Variable camshaft control (10) according to one of claims 1 to 4, characterized

characterized in that the passage (16a, 16b, 16c, 16d) extends in the radial direction through the cam piece (14).

6. Variable camshaft control (10) according to claim 1, characterized in that the lubricant supply device (20) has at least one through the camshaft (12) extending bore (28). Variable camshaft control (10) according to claim 6, characterized in that the camshaft (12) is a hollow shaft and the at least one bore (28) extends in the radial direction through the camshaft (12).

Internal combustion engine with a variable camshaft control (10) according to at least one of the preceding claims 1 to 7.