EP3215721A1

EP3215721A1 - Camshaft comprising an axially guided sliding element

Info

Publication number: EP3215721A1
Application number: EP15744947.1A
Authority: EP
Inventors: Jürgen MEUSEL; Michael Kunz
Original assignee: ThyssenKrupp Presta TecCenter AG
Current assignee: Thyssenkrupp Dynamic Components Teccenter AG
Priority date: 2014-11-07
Filing date: 2015-08-03
Publication date: 2017-09-13
Anticipated expiration: 2035-08-03
Also published as: JP6535736B2; CN107075986A; DE102014116256B4; DE102014116256A1; EP3215721B1; WO2016071015A1; CN107075986B; JP2018500490A; US10054013B2; US20170314425A1

Abstract

The invention relates to a camshaft (1) comprising a main shaft (10) on which at least one sliding element (11) is accommodated in such a way as to be axially movable along a shaft axis (12); the main shaft (10) has an outer longitudinal tooth structure (13) that meshes with an inner tooth structure (14) introduced into a passage in the sliding element (11) so that the sliding element (11) is disposed in a rotationally fixed manner on the main shaft (10); on the axial end faces, the sliding element (11) has guiding portions (15), by means of which the sliding element (11) is guided on the main shaft (10) in order to minimize axial offset of the sliding element (11). According to the invention, guiding sleeves (16) on which the guiding portions (15) of the sliding element (11) are supported are accommodated on the main shaft (10).

Description

Camshaft with an axially guided sliding element

Description

The present invention relates to a camshaft having a basic shaft on which at least one sliding element is axially slidably received along a shaft axis, wherein the fundamental shaft has an external long gearing which engages in an inserted in a passage in the sliding element internal teeth, so that the sliding member rotationally fixed on the fundamental shaft is arranged, and wherein the sliding element has on its axial end sides of guide portions through which the sliding element is guided to minimize a desalination of the sliding element on the fundamental shaft.

STATE OF THE ART

From DE 10 201 1 086 161 A1, a camshaft with a basic shaft is known, and on the fundamental shaft, a sliding element along the shaft axis of the camshaft is received axially displaceable. The basic shaft has an outer long toothing, and the outer long toothing engages in an internal toothing, which is introduced in a passage in the sliding element. As a result, the sliding element on the fundamental shaft in the shaft axis direction is axially displaceable, however, the sliding element can not be rotated on the fundamental shaft, so that torques can be transmitted from the fundamental to the sliding element.

In the recording of sliding elements on a provided with an external long-toothed fundamental wave basically results in the problem of a possible backlash-free guidance of the sliding element. The sliding element must, to allow a trouble-free, permanent tap lifting information from a cam track of the sliding element on a pick-off element, possibly performed without radial play on the fundamental shaft. A minimum clearance of the sliding element on the Basic wave leads to a minimization of the deshancing of the sliding element on the fundamental shaft, so that it is desirable to carry out the desaxing as small as possible.

To decouple a leadership of the sliding element on the fundamental shaft of the teeth of the outer long teeth of the fundamental shaft with the internal teeth in the sliding element, DE 10 201 1 086 161 A1 further proposes to provide on the sliding element guide portions through which the sliding element to minimize the deshancing on the Fundamental wave is guided. The guide sections on the sliding element run against the tooth tips of the external long-toothing of the fundamental shaft, which, however, can cause premature wear of the guide sections. If cylindrical guide sections were to be provided on the basic shaft, then the sliding element could no longer be mounted with the internal toothing, since the internal toothing in the passage of the sliding element has a smallest diameter which would be smaller than the cylinder section for guiding the sliding element on the fundamental shaft. If the guide sections on the sliding element have a smaller diameter and sit on a cylinder section on the basic shaft, which likewise has a smaller diameter, then the sliding element could likewise no longer be mounted, since the external longitudinal toothing on the basic shaft pushes the sliding element with guide sections of smaller diameter impossible.

DISCLOSURE OF THE INVENTION

The object of the invention is the development of a camshaft with a minimized deshaching of an axially displaceable sliding element on a basic shaft, wherein the sliding element is to be guided radially over guide sections against the fundamental shaft.

This object is achieved on the basis of a camshaft according to the preamble of claim 1 in conjunction with the characterizing features. Advantageous developments of the invention are specified in the dependent claims. To solve the above problem, the invention includes the technical teaching that guide sleeves are received on the basic shaft against which the guide sections of the sliding element are supported.

The invention is based on the general idea of being able to perform the geometric configuration of the external long teeth on the fundamental shaft and the internal teeth in the passage of the sliding element in a known manner, but the invention separate guide sleeves allow a guide of the sliding element without the guide sections a smaller diameter than the largest diameter of the external long teeth. Thus, the sliding element can be guided over the guide portions against a cylindrical outer peripheral surface. An assembly of the camshaft takes place in a simple manner, since first the sliding element can be applied to the fundamental shaft, and only then can the guide sleeves or at least one final guide sleeve are applied laterally to the sliding element on the fundamental shaft.

The guide sleeves, for example, have an inner diameter which corresponds to the tip diameter of the outer longitudinal toothing. Thus, the guide sleeves can be applied to the tooth tips of the external longitudinal teeth. With particular advantage, the guide sleeves may have internal teeth, and the internal teeth in the guide sleeves may be designed so that they can sit on the outer longitudinal teeth of the fundamental, so that teeth of the internal teeth in tooth spaces between the teeth of the external longitudinal teeth. In this case, the dimensioning of the internal toothing of the guide sleeves can be designed so that the guide sleeves can be firmly applied to the external longitudinal toothing.

With particular advantage, the guide sleeves can be shrunk or pressed onto the basic shaft. For example, the guide sleeves can be heated and / or the fundamental wave can be cooled, so that the guide sleeves can be applied in the manner of a cross press dressing on the fundamental shaft. It is also conceivable that the guide sleeves are pressed in the shaft axis direction on the fundamental wave to create a longitudinal compression bandage.

To guide a sliding element, two guide sleeves may be provided, and the guide sleeves may be arranged in the shaft axis direction seen laterally to the region of engagement of the external long teeth in the internal teeth on the fundamental shaft. In this case, the guide sleeves may have a distance from one another, which allows the sliding element to be moved axially on the basic shaft in order to bring different cam tracks into operative connection with a tapping element for valve actuation. In particular, the guide portions of the sliding element may be formed with the guide sleeves with such an axial overlap that an axial displacement of the sliding element while maintaining the guidance of the guide portions is made possible on the guide sleeves.

The guide sleeves can be applied in different ways on the fundamental shaft. For example, the outer long teeth can be designed without interruption along the shaft axis, so that the inner teeth of the guide sleeves can be brought into engagement with the outer long teeth independently of a position along the shaft axis. The outer longitudinal teeth are designed to be invariable in the axial direction, and the outer longitudinal teeth may have the same configuration in the region of the seating of the guide sleeves as in the region in which the outer longitudinal teeth with the internal teeth in the passage of the sliding element is engaged. As a result, the production of the fundamental wave is facilitated, in particular when the external longitudinal toothing does not have to have any divergent sections along the shaft axis.

Alternatively, it can be provided that the outer longitudinal toothing has cylindrical receiving sections, so that the fundamental shaft has alternating cylindrical sections with the outer longitudinal toothing. In this case, the internal toothing of the guide sleeves with trained on this tooth heads sit on the cylindrical receiving section. However, the internal teeth in the guide sleeves remains necessary, otherwise the guide sleeves could not be performed on the adjacent outer longitudinal teeth on the fundamental shaft. For example, while the cylindrical receiving portion on the fundamental shaft have a diameter which, for example, is slightly larger than the diameter of the Fußkreisdurchmessers the outer longitudinal toothing.

Furthermore, the fundamental wave and thus the camshaft for rotatable mounting can be arranged in bearing bridges. The bearing bridges can be part of the cylinder head of an internal combustion engine or part of a hood module in which one or more camshafts are received. The guide sleeves may have a longitudinal portion which forms a bearing inner ring for storage in the bearing bridge. According to the invention thus the guide sleeves can be used not only for radial guidance of the axial movement of the sliding elements, and the guide sleeves can also form bearing rings, which form with the bearing bridges slide bearing arrangements for supporting the camshaft.

For example, the guide sleeves may have a cylindrical outer peripheral surface, against which the guide portions of the sliding element and at the same time the bearing bridge are supported or accommodated. In particular, the external longitudinal toothing of the basic shaft can have interruption sections under the longitudinal sections of the guide sleeves, which form the sliding bearing arrangement with the bearing bridges. Consequently, no interference fit of the internal toothing of the guide sleeves with the external longitudinal toothing of the fundamental shaft is generated by the interruption sections, so that the concentricity of the outer circumferential surface is not impaired by the compression of the internal toothing with the external longitudinal toothing of the fundamental shaft. Otherwise, the multiple support of the guide sleeves could press below the slide bearing assembly with the bearing bridges on the tooth heads of the internal teeth a polygonal structure in the guide sleeve, which adversely affects the Rundlaufmaß. Sliding elements can be designed with a carrier tube on which a plurality of functional elements are applied. The functional elements may, for example, form cam elements or an adjustment member, and the adjustment member serves for the axial adjustment of the sliding element on the basic shaft, and may cooperate with an adjusting manipulator which is stationary in the installation environment of the camshaft. For example, the support tube can be designed so long that the functional elements protrude laterally beyond the support tube, and the guide sections can be formed on the inside of at least one functional element. For example, the functional elements, ie in particular the cam elements, can be applied via a cylindrical compression bandage on the outside of the carrier tube and protrude laterally beyond the carrier tube. The protruding part of the functional element releases an inner cylindrical section which forms the guide section and forms the radial guide of the same with the outer peripheral surface of the guide sleeve.

PREFERRED EMBODIMENT OF THE INVENTION

Further, measures improving the invention will be described in more detail below together with the description of a preferred embodiment of the invention with reference to FIGS. It shows:

Fig. 1 is a cross-sectional view of a camshaft with

Guide sleeves, which are applied on receiving portions between an external longitudinal toothing on the fundamental shaft,

Fig. 2 shows a modified embodiment of a camshaft with

Guide sleeves which rest on a continuous outer longitudinal toothing of the fundamental shaft,

Fig. 3 shows another embodiment of a camshaft with

Guide sleeves, which rest on the outer longitudinal teeth of the fundamental shaft, wherein the outer longitudinal teeth has a break portion. In Figure 1, a camshaft 1 according to a first embodiment of the invention is shown in sections. The camshaft 1 has a basic shaft 10 which extends along a shaft axis 12. On the fundamental shaft 10, a sliding element 1 1 is added, which is axially displaceable along the shaft axis 12. The camshaft 1 in this case basically has a plurality of sliding elements 1 1, which may each preferably be received in the same way on the fundamental shaft 10. To support the camshaft 1, for example, in a cylinder head or in a modular hood, bearing bridges 19 are provided, and the camshaft 1 is rotatably received about the shaft axis 12 with reference to the length section shown by way of example in two bearing bridges 19.

The fundamental shaft 10 has an outer longitudinal toothing 13, wherein the outer longitudinal toothing 13 is shown interrupted several times along the shaft axis 12.

The sliding element 1 1 has a support tube 21, and in the inner passage of the support tube 21, an internal toothing 14 is formed. The internal toothing 14 engages in the external longitudinal toothing 13 of the basic shaft 10, so that the sliding element 1 1 is held rotationally and slidably on the basic shaft 10 along the shaft axis 12. The tolerancing or dimensioning of the outer longitudinal toothing 13 in relation to the internal toothing 14 is provided so that only the torque transmission is ensured, a radial guide with a minimal disalignment of the sliding element 1 1 on the fundamental shaft 10 via the teeth between the external longitudinal teeth 13 and the internal teeth 14 not.

For radial guidance of the sliding element 1 1 guide portions 15 are formed on these, and the guide portions 15 against guide sleeves 16, which are received on the fundamental shaft 10. Thus, the guide sleeves 16 support the sliding element 1 1 via the guide portions 15.

The guide portions 15 are formed on functional elements 22 which are received on the support tube 21. The embodiment shows this Sliding element 1 1 with two functional elements 22 which are formed as cam elements 23 with different cam tracks. Between the two cam elements 23 shown is an adjustment member 24, via which the sliding element 1 1 can be moved on the fundamental shaft 10 in the shaft axis direction with a manipulator, not shown. Shown is the sliding element 1 1 with respect to the image plane in a left position, so that the left side guide portion 15 with the left guide sleeve 16 has a larger overlap than the right trained guide portion 15 with the right guide sleeve 16. The two guide sleeves 16 are adjacent to the teeth of the outer long teeth 13 arranged with the internal teeth 14 in the support tube 21, wherein the distance between the two guide sleeves 16 is formed so that the axial mobility of the sliding element 1 1 is maintained.

The guide sleeves 16 have an internal toothing 17, wherein the internal toothing 17 is designed so that it can be guided across the external long teeth of the base shaft 10 in the shaft axis direction away. In this case, the exemplary embodiment shows the fundamental shaft 10 with interruptions in the external long-toothing 13, so that seating points 16 for generating the guide sleeves 16 are formed by cylindrical receiving sections 25. On the cylindrical receiving portions 25, the guide sleeves 16 sit with their tooth tips 17a of the internal teeth 17, and the guide sleeves 16 can be shrunk or pressed onto the receiving portions 25. For example, the diameter of the receiving portions 25 may be dimensioned so that it is slightly larger than the root diameter of the outer long teeth 13 of the fundamental wave 10. Thus, the guide sleeves 16 are guided over the external long teeth 13 to the settling points, which are formed by the receiving portions 25. Reach the guide sleeves 16, the receiving portions 25, the compression is carried out with the fundamental wave 10 in the longitudinal compression bandage or in the transverse compression bandage.

The guide sleeves 16 have a length which is determined so that the guide sleeves 16 with a longitudinal portion 16 a to below or in the Bearing bridges 19 extend into it. As a result, the guide sleeves 16 with their outer peripheral surface 20 form a slide bearing arrangement with the bearing bridges 19, so that the camshaft 1 can be mounted rotatably about the shaft axis 12 via the guide sleeves 16. Thus, the guide sleeves 16 fulfill both a guiding function of the sliding element 1 1 on the guide element 15 formed on the sliding element 1 1 and a bearing function for supporting the camshaft 1 in the bearing bridges 19. The outer peripheral surface 20 of the guide sleeves 16 can be dimensioned and surface-treated the guide sleeves 16 can serve as bearing inner rings for the sliding bearing in the bearing bridges 19.

FIG. 2 shows a modified exemplary embodiment of the camshaft 1 with a basic shaft 10 designed to reduce weight, which extends along a shaft axis 12. On the fundamental shaft 10, a sliding element 1 1 is added, and the sliding element 1 1 has a support tube 21 which receives two cam elements 23 and an adjusting member 24. On the inside, the support tube 21 has an internal toothing 14, which engages in an external longitudinal toothing 13 of the fundamental shaft 10. As a result, the sliding element 1 1, as already described in connection with Figure 1, received axially movable and rotationally fixed on the fundamental shaft 10.

The fundamental shaft 10 is formed with a continuous along the shaft axis 12 outer longitudinal toothing 13, so that it is uninterruptible and all elements are added to the outer longitudinal teeth 13 itself. Laterally to the arrangement of the sliding element 1 1 10 guide sleeves 16 are added to the outer longitudinal teeth 13 of the fundamental wave, which have an internal toothing 17 on the inside. This engages in the external longitudinal toothing 13 of the fundamental shaft 10, and the internal toothing 17 is dimensioned so that it is pressed onto the external longitudinal toothing 13 of the fundamental shaft 10 in the transverse compression bandage or in the longitudinal compression bandage. In particular, tooth heads 17a of the internal toothing 17 are shown, via which the guide sleeve 16 can be pressed onto the external longitudinal toothing 13, for example by the tooth head dimension of the internal toothing 17 being larger (ie smaller Tip diameter) is performed as the Zahnfußmaß the outer long teeth. 13

The exemplary embodiment shows guide sleeves 16 with a longitudinal section 16a which extends into the bearing bridges 19, so that the guide sleeves 16 with the bearing bridges 19 form a sliding bearing arrangement of the camshaft 1.

On the inside in the cam elements 23 guide portions 15 are formed, which are guided on the outer peripheral surface 20 of the guide sleeves 16, whereby the radial guidance of the sliding element 1 1 is achieved. The Führungsmaß between the guide portions 15 and the outer peripheral surface 20 of the guide sleeves 16 may be determined so that a minimal desalination of the sliding element 1 1 is achieved on the fundamental shaft 10.

Finally, FIG. 3 also shows a modified exemplary embodiment of the camshaft 1 with a basic shaft 10 which has interruption sections 18. The guide sleeves 16 are arranged along the shaft axis 12 at positions on the fundamental shaft 10 at which the interruption portions 18 are located. In this case, the interruption portions 18 correspond to the bearing bridges 19 for rotatably receiving the camshaft 1 via the guide sleeves 16, and the guide sleeves 16 serve via their outer peripheral surface 20 for mounting the camshaft 1 in the bearing bridges 19th

The guide sleeves 16 are made longer than the width of the interruption portions 18 in the shaft axis direction, so that the guide sleeves 16 are applied to their outer sides on the outer longitudinal teeth 13 of the fundamental wave 10, in particular pressed. The section over which the bearing bridges 19 with the outer peripheral surface 20 of the guide sleeves 16 forms a sliding bearing, thus has no interference fit of the internal teeth 17 of the guide sleeves 16 with the outer longitudinal teeth 13 of the fundamental shaft 10, so that the concentricity of the outer peripheral surface 20 by the compression of the internal teeth 17 with the outer longitudinal teeth 13 of the fundamental wave 10 is not deteriorated. The guide of the sliding element 1 1 on the guide sleeves 16 is carried out in the manner described above on the guide portions 15 which are formed on cam elements 23 which are received on a support tube 21 of the sliding element 1 1. Between the two cam elements 23, an adjusting member 24 for axial displacement of the sliding element along the shaft axis 12 on the basic shaft 10 is formed. For torque transmission between the fundamental shaft 10 and the sliding element 1 1 is an internal toothing 14, which is introduced on the inside in the support tube 21 and which cooperates with the external longitudinal toothing 13.

The invention is not limited in its execution to the above-mentioned preferred embodiment. Rather, a number of variants is conceivable, which makes use of the illustrated solution even with fundamentally different types of use. All of the claims, the description or the drawings resulting features and / or advantages including structural details or spatial arrangements may be essential to the invention both in itself and in various combinations.

T o o u rs a n d i o n s

camshaft

fundamental wave

sliding element

shaft axis

Outdoor long teeth

internal gearing

guide section

guide sleeve

a length section

internal gearing

a tooth head

interrupting section

bearing bridge

Outer circumferential surface

support tube

functional element

cam member

Versteilglied

receiving portion

Claims

Patent claims

1 . Camshaft (1) with a basic shaft (10) on which at least one sliding element (1 1) along a shaft axis (12) is axially slidably received, wherein the basic shaft (10) has a Außenlangsverzahnung (13), which in one in one passage in the sliding element (1 1) introduced internal toothing (14) engages, so that the sliding element (1 1) rotatably on the basic shaft (10) is arranged, and wherein the sliding element (1 1) at its axial end sides guide portions (15) through which the sliding element (1 1) for minimizing a desalination of the sliding element (1 1) on the fundamental shaft

(10) is guided,

characterized in that on the basic shaft (10) guide sleeves (16) are received, against which the guide portions (15) of the sliding element

(1 1) are supported.

2. camshaft (1) according to claim 1, characterized in that the guide sleeves (16) have an internal toothing (17).

3. Camshaft (1) according to claim 1 or 2, characterized in that the guide sleeves (16) are shrunk or pressed onto the basic shaft (10).

4. camshaft (1) according to one of claims 1 to 3, characterized in that the guide sleeves (16) seen in the shaft axis direction laterally to the region of engagement of the external long teeth (13) in the internal toothing (14) on the fundamental shaft (10) are.

5. camshaft (1) according to one of the preceding claims, characterized in that the external long-toothing (13) along the shaft axis

(12) is carried out without interruption, so that the internal toothing (17) of the guide sleeves (16) with the outer long toothing (13) independently of a position along the shaft axis (12) is engageable.

6. camshaft (1) according to one of claims 1 to 4, characterized in that the outer longitudinal toothing (13) cylindrical receiving portions (25), wherein the internal toothing (17) of the guide sleeves (16) formed on this tooth heads (17 a) the cylindrical receiving portions (25) is seated.

7. camshaft (1) according to one of the preceding claims, characterized in that the basic shaft (10) in bearing bridges (19) is rotatably locatable, wherein the guide sleeves (16) have a longitudinal portion (16 a) having a bearing inner ring for storage in the Bearing bridge (19) forms.

8. camshaft (1) according to one of the preceding claims, characterized in that the guide sleeves (16) have a cylindrical outer peripheral surface (20), against which the guide portions (15) of the sliding element (1 1) and preferably the bearing bridge (19) supported are and / or wherein the outer longitudinal teeth (13) of the basic shaft (10) interruption portions (18) under the longitudinal portions (16a) of the guide sleeves (16) which form the sliding bearing arrangement with the bearing bridges (19).

9. camshaft (1) according to one of the preceding claims, characterized in that the guide portions (15) of the sliding element (1 1) with the guide sleeves (16) are formed with such an axial overlap that an axial displacement of the sliding element (1 1 ) while maintaining the guidance of the guide sections (15) on the guide sleeves (16).

10. camshaft (1) according to any one of the preceding claims, characterized in that the sliding element (1 1) comprises a support tube (21) on which functional elements (22) of the sliding element (1 1) are accommodated, wherein the guide portions (15) are formed on at least one functional element (22).