WO2005052339A1

WO2005052339A1 - Damping device integrated into a pivot bearing

Info

Publication number: WO2005052339A1
Application number: PCT/EP2004/010432
Authority: WO
Inventors: Ralph Painta; Michael Bogner; Herbert Graf
Original assignee: Schaeffler Kg
Priority date: 2003-10-31
Filing date: 2004-09-17
Publication date: 2005-06-09
Also published as: DE10350939A1

Abstract

The invention relates to a traction mechanism drive (1) of an internal combustion engine (7), said drive comprising a pivotable driving body (5) as a clamping device. At least one damping device (16) embodied as a clamping element (15a, 15b) is integrated into the pivot bearing (8) of the drive body, in an annular region (14) thereof.

Description

Damping device integrated in a pivot bearing

Field of the Invention

The invention relates to a traction mechanism drive of an internal combustion engine, which is intended for driving units. A traction device, in particular a belt, connects pulleys or belt pulleys of an output member and at least one drive member. For this purpose, a pulley connected to the crankshaft of the internal combustion engine is preferably provided as the output member, from which units of the internal combustion engines are driven, the traction means connecting the pulleys of all the organs connected to the traction means drive. A pivotably arranged drive element, which is acted upon by a spring means, is provided in order to increase the pretension of the traction means. The tensioning device is also assigned a damping device to compensate for vibrations of the traction mechanism drive. Background of the Invention

A traction mechanism drive is preferably used to drive the individual units of an internal combustion engine, such as a water pump, air conditioning compressor, generator or power steering pump, in which a belt connects the individual belt pulleys of the units to be driven with the belt pulley arranged on the crankshaft of the internal combustion engine in a rotationally fixed manner. The slip-free drive of this traction mechanism drive requires a tensioning device, which automatically over the entire life span even when the traction mechanism is elongating. duration of the internal combustion engine ensures sufficient tension of the traction means.

Known tensioning devices, such as the device shown in DE 196 47 225 A1, comprise a force-loaded tensioning roller which is guided on the traction means. The structure of this tensioning device is further provided with a base part arranged in a rotationally fixed manner, the axis of symmetry of which simultaneously forms the axis of rotation for the swivel arm, on the outside of which the tensioning roller is rotatably arranged. A torsion spring is arranged between the base part and the swivel arm in order to achieve a non-positive support of the tensioning roller on the traction means. As a damping device, a pressure cone is provided as a separate component, which, by means of a pressure spring arranged between the base part and the pressure cone, corresponds non-positively in an inner cone of the swivel arm designed with the outer contour of the pressure cone.

DE 100 57 818 A1 discloses a traction mechanism drive of an internal combustion engine designed as a two-disc drive. The drive element of the traction mechanism drive is pivotably arranged and is supported on the internal combustion engine via a spring means, in order to achieve a sufficient pre-tensioning of the traction mechanism, which ensures a slip-free traction mechanism drive. This known device provides a spring-damper unit as spring means in order to achieve a traction mechanism drive that is as vibration-free as possible. Summary of the invention

Taking known tensioning devices for traction mechanism drives into account, it is the object of the present invention to realize a component-optimized and space-optimized with a tensioning device which is combined with the damping device.

This problem is solved by the features of claim 1 of the present invention. According to the invention, a pivot bearing which also functions as the tensioning device and is combined with the damping device is assigned to the pivotable unit. This structure enables further optimization of the component and installation space, since a simple spring means without a damping device, for example a spring means designed as a coil spring, can be assigned to the pivoting unit provided with the pivot bearing according to the invention. The invention provides as a damping device a force-actuated clamping element including two friction cones. When installed, the force-applied friction cones enable effective damping of undesired adjusting movements of the pivotably arranged drive element. In particular, the vibrations caused by the combustion process of the internal combustion engine and introduced into the traction mechanism drive as rotational non-uniformity can be damped.

The operation of the damping device according to the invention is based on the principle of a clamping element connection, in which an axial force spreads the friction cones connected via conical contact surfaces radially inwards and outwards, as a result of which relative movements between an inner component and an outer component on which the respective friction cones are supported are damped. The axially acting spring means integrated in the pivot bearing is advantageously supported on an inner friction cone and, in cooperation with the outer friction cone, generates a desired spreading force in the radial direction. The friction cones are supported by a contact surface running in a cone angle, the cone angle being designed with regard to optimal damping on the one hand and to avoid a self-locking effect on the other. Furthermore, the axial force acting on the clamping element is dimensioned in such a way that a frictional connection is avoided, which brings about a torsionally rigid connection between the fixedly arranged component and the pivotable component of the rotary bearing. Due to the integrated solution, in which the pivot bearing is combined with the damping device, the invention reduces the required installation space and at the same time optimizes the scope of components. The invention advantageously replaces the spring damping systems previously used for such tensioning systems or tensioning devices with a pure spring element, since the required damping of the traction mechanism drive takes place according to the invention with the tensioning element integrated in the pivot bearing of the pivotable drive element.

Further advantageous embodiments of the invention are the subject of dependent claims 2 to 13.

The friction cones are preferably designed such that they effectively avoid a disadvantageous self-locking effect. For this purpose, a cone angle of α <20 ° is provided. This angular value ensures, on the one hand, a desired damping of positioning movements of the pivotable drive element and, on the other hand, a permanent, wear-free relative movement between the friction cones. The cone angle is designed in particular depending on the material of the friction cones and the required friction forces of the clamping element.

The invention includes, as a damping device, differently designed or arranged friction cones of the tensioning elements. On the one hand, the relative movement can take place directly between the contact surfaces of the friction cones. Alternatively, the relative movement between the outer surface of the outer friction cone and the associated support surface of the rotary bearing can be provided. The invention further includes an arrangement in which there is a relative movement between the inner diameter of the inner friction cone and the associated support surface.

As a measure to achieve a specific relative movement between two components, the invention includes, for example, a positionally fixed arrangement of the friction cones on the components of the rotary bearing on which the friction cones are supported. This structure ensures a preferred relative movement exclusively between the contact surfaces of the friction cones of the clamping element.

The configuration of the tensioning element, with which an effective damping of positioning movements of the pivotable drive element can be achieved, comprises two cones of opposite conical design. An outer friction cone has a cylindrical outer surface and a conical contact surface on the inside. The associated internal friction cone forms a cylindrical inside and a conical contact surface on the outside.

The tensioning element is inserted in the installed state in a circular annular space of the rotary bearing, which is delimited radially on the outside by a bore of a torsionally rigid, stationary housing and radially on the inside by a bolt directly connected to the pivotable drive element.

As an alternative to this, it is possible to design the pivot bearing in such a way that the annular space is delimited radially on the outside by a bore in a bracket which is directly connected to the pivotable drive element and on the inside by the lateral surface of a bolt which is connected to the rigidly arranged, stationary housing Connection is established.

A further advantageous embodiment of the invention provides for two axially spaced clamping elements to be arranged in the rotary bearing, between which a compression spring exerting axial forces on the clamping elements is arranged as spring means. This structure advantageously provides two clamping elements arranged on the outside of the rotary bearing, which has an advantageous effect on the installation position of the pivotably arranged drive element. Due to the symmetrical arrangement of the clamping elements in the pivot bearing, there is no need for a further rolling bearing or sliding bearing in the annular space of the pivot bearing, since the double clamping element arrangement ensures a defined installation position of the swiveling drive shaft. For a rotary bearing comprising two axially spaced clamping elements, the invention provides for an installation position that simplifies assembly. For this purpose, it is advisable to insert the tensioning elements into the annular space of the pivot bearing in such a way that the associated compression spring is supported on the front on the inner friction cones.

In the installed state of the rotary bearing, each external friction cone of the tensioning elements is also advantageously supported axially on a cover, which further defines the installation position of the outer component of the rotary bearing. The cover is fixed in position in a groove of the bolt.

The invention further includes sealing the annular space in the pivot bearing, which is intended to accommodate the tensioning elements according to the invention. An elastic seal, for example an O-ring, is particularly suitable for this purpose, which is inserted in a form-fitting manner in an end receptacle of the outer component of the rotary bearing and fills it in a sealing manner. The receptacle, which is open radially inwards and is intended for the seal, is delimited at the end by the cover on which the external friction cone and the external component are fixed in position. This effectively prevents contamination from entering the annular space of the rotary bearing.

A further advantageous embodiment of the invention provides for a rotary bearing to be implemented which, in addition to a tensioning element, also has a damping device and a spring means. This measure makes it possible to dispense with a spring means which is used separately from the rotary bearing, which advantageously reduces the required component scope of the tensioning device and simplifies assembly. To implement this spring means integrated in the pivot bearing, it is advisable to use a torsion spring which is attached with a spring end to the stationary component of the pivot bearing and is fixed with the further spring end to the pivotable component of the pivot bearing. As a swiveling unit that performs the function of the tensioning device, it makes sense to provide a starter generator. When starting, this unit has the task of driving the internal combustion engine. Immediately after the internal combustion engine has started, that is to say, normal operation or generator operation of the starter generator is established, in which the engine is driven by the internal combustion engine.

Brief description of the drawings

Several embodiments of the invention are shown in the drawings, which are described in more detail below. Show it:

Figure 1 is a schematic representation of a traction drive comprising two pulleys;

Figure 2 is a side view of a pivotably arranged drive member, which simultaneously forms the function of a tensioning device for a traction mechanism drive; Figure 3 is an enlarged view of the pivot bearing of the pivotally arranged drive member;

Figure 4 shows an alternative to Figure 3 rotary bearing for a pivotable drive member.

Detailed description of the drawings

FIG. 1 shows a traction mechanism drive 1, which includes a traction mechanism 2, in particular a belt. The traction means 2 connects a first pulley 3 assigned to an output element 4 to a second pulley 6 assigned to a drive element 5. A pulley 3 connected to a crankshaft of an internal combustion engine 7 is provided as the output element 4. The drive member 5 forms a pivotally arranged unit of the Internal combustion engine 7, preferably a starter generator. The drive member 5 is pivotally arranged via a pivot bearing 8 so that it supports the traction means 2, supported by the weight of the drive member, to achieve a slip-free drive. A spring means 9 inserted between the internal combustion engine 7 and the drive element 5 reinforces the pretensioning of the traction means 2.

FIG. 2 illustrates the fastening of the drive member 5 and in particular the design of the rotary bearing 8. The drive member 5 as a starter generator is connected to the internal combustion engine 7 shown in FIG. 1 by means of a separate lever 10. The end of the lever 10 has a bore 11 which is intended for a bolt 12. At both ends, the bolt 12 is fixed in position in the fastening slugs 13a, 13b of the drive element 5. An annular space 14, which is delimited radially on the inside by the bolt 12 and radially on the outside by the bore 11, serves to accommodate two axially offset clamping elements 15a, 15b. A compression spring 39 is inserted between the tensioning elements 15a, 15b, which in the installed state causes the tensioning elements 15a, 15b, which are constructed in two parts and form a damping device 16, to spread.

The damping device 16 has the task of effectively dampening a vibration excitation of the traction mechanism drive 1, which is triggered in particular by the rotational irregularity of the internal combustion engine 7 and leads to vibrations of the traction mechanism 2, i. H. to avoid uncontrolled adjusting movements or pivoting movements of the drive member 5 around the axis of rotation of the rotary bearing 8. The spring means 9 is rotatably supported with a first articulation point 17 on a holding bracket 18, the holding bracket 18 being fastened to the internal combustion engine 7 in the installed state. The spring means 9 is connected to the drive element 5 with a second articulation point 19.

FIG. 3 shows the detailed structure of the rotary bearing 8, including all individual parts of the damping device 16. Two axially offset clamping elements 15a, 15b, each arranged on the end sides of the rotary bearing 8, form the Damping device 16. Each clamping element 15a, 15b is composed of an inner friction cone 20, to which an outer friction cone 21 is assigned. The internal friction cone 20, which is cylindrical on the inside, is supported in the installed state on the lateral surface of the bolt 12 serving as a support surface 22. The conically shaped outer surface of the inner friction cone 20 forms, together with the inner friction cone 21, which is conical on the inside. The outer cylindrical cone 21 on the outside is supported in the installed position on a support surface 24 of the bore 11 in the lever 10. A spreading force is exerted on the tensioning elements 15a, 15b by means of the compression spring 39, which is supported at the end on the inner friction cones 20.

The damping device 16, the construction of which comprises two axially spaced clamping elements 15a, 15b, each comprising an inner friction cone 20 and an outer synchronizing ring 21, which are designed as closed rings and are supported by a conical contact surface 23, are displaced into one another by the force application of the compression spring 39 and deformed to a limited extent. To avoid self-locking, all friction cones of the tensioning element 15a, 15b are provided with a cone angle "α-i", "α ₂ " of <20 °. The design of the cone angle "CH", "α ₂ " can be influenced by the choice of the material from which the components of the clamping element 15a, 15b are made.

As a measure to enable a defined relative movement between the inner friction cone 20 and the outer friction cone 21 in the area of the contact surface 23, the individual friction cones are fixed to the respective support surfaces 22, 24. For this purpose, the inner friction cone 20 is provided with a radially inwardly directed lug 25 which engages in a form-fitting manner in a corresponding longitudinal groove or recess 26 in the bolt 12. Correspondingly, the outer friction cone 21 has a radially outwardly directed nose 27 which interacts with a longitudinal groove or recess 28 in the lever 9 in the region of the bore 11. In order to achieve a defined installation position of the tensioning elements 15a, 15b, covers 29, which are designed in the manner of disks, are assigned to them, on which the outer friction cone 21 is supported. The preferably slotted, radially biased cover 29 are positively inserted in a groove 30 of the bolt 12 to achieve a positionally fixed arrangement. To achieve an effective sealing of the annular space 14, a seal 31 is provided on both sides of the rotary bearing 8, which is inserted in each case in an end recess 32 of the lever 10. In the installed position, the seal 31 is non-positively and thus sealingly supported on the front side of the cover 29.

FIG. 4 shows the rotary bearing 8, which on the one hand has a damping device 16 with a tensioning element 15a, corresponding to the structure shown in FIG. 3. Furthermore, the spring means 33 designed as a torsion spring is integrated into the annular space 14 and exerts a force component on the drive element 5 in order to increase the pretensioning of the traction means 2. This structure eliminates the need for a separate spring means 9, as shown in FIG. 1. The spring means 33 engages in a form-fitting manner with a spring end 34 which is bent radially outward into a longitudinal groove 35 of the lever 10. In the installed position, the further spring end 36 engages in a longitudinal groove 37 of the bolt 12. The spring means 33 is pretensioned so that, transferred to the representation of the traction mechanism drive 1 according to FIG. 1, it triggers a counterclockwise force component on the drive element 5. A sliding bearing 38 is also inserted in the annular space 14, in a section axially delimited by the spring means 33 and the cover 29. In conjunction with the tensioning element 15a, the slide bearing 38 has the task of ensuring that the drive element 5 is aligned with the lever 10 as free of play as possible.

reference numerals

Traction drive 30 groove traction device 31 gasket pulley 32 recess output element 33 spring means drive element 34 spring end pulley 35 longitudinal groove internal combustion engine 36 spring end rotary bearing 37 longitudinal groove spring means 38 slide bearing lever bore Bolzena mounting pin b mounting benefit ring space clamping element b tensioning element damping device articulation point mounting bracket articulation point internal friction cone external friction cone contact support surface Nose recess Nose recess cover

Claims

claims

1. traction mechanism drive of an internal combustion engine (7), which is intended for driving aggregates, a traction mechanism (2) connecting pulleys (3, 6) of an output element (4) and at least one drive element (5) and one around a rotary bearing (8) Pivotal drive element (5) in conjunction with a spring means (9, 33) also serves as a tensioning device and the drive element (5) includes a damping device (16) to compensate for vibrations, characterized in that the damping device (16) directly in a pivot bearing (8) of the pivotable drive element (5) is integrated and includes at least one force-actuated tensioning element (15a, 15b) comprising an internal friction cone (20a, 20b) and an external friction cone (21a, 21b).

2. Traction drive according to claim 1, wherein the inner friction cone (20a, 20b) and the outer friction cone (21a, 21b) each have a cone angle "α" α ₂ "of ≤ 20 °.

3. traction drive according to claim 1, wherein to achieve a defined relative movement between the inner friction cone (20a, 20b) and the outer friction cone (21a, 21b) of the clamping element (15a, 15b) each cone is fixed in position relative to the component on which it is supported.

4. traction drive according to claim 1, wherein the clamping element (15a, 15b) has an outer cylindrical and inner conical outer friction cone (21a, 21b) and an outer conical and inner cylindrical inner friction cone (20a, 20b), which are joined together in a form-fitting manner, and the clamping element (15a, 15b) is inserted in an annular space (14) of the rotary bearing (8).

5. traction drive according to claim 4, wherein the annular space (14) is delimited radially on the outside by a bore (11) of a housing or a lever (10) directly connected to the internal combustion engine (7), via which the drive member (5) on the internal combustion engine (7) is fixed and radially inside by a bolt (12) which is connected to the pivotable drive member (5).

6. traction mechanism drive according to claim 4, wherein the annular space (14) is delimited radially on the outside by a bore (11) of a bracket directly connected to the pivotable drive element (5) and radially on the inside by a bolt which is directly or indirectly connected to the internal combustion engine (7) communicates.

7. traction mechanism drive according to claim 1, wherein in the annular space (14) two axially spaced clamping elements (15a, 15b) are inserted, between which a compression spring (39) acting on both clamping elements (15a, 15b) is arranged.

8. traction mechanism drive according to claim 7, wherein in an installed position, the compression spring (39) is supported at the end on the inner friction cone (20a, 20b) of the tensioning elements (15a, 15b).

9. traction drive according to claim 1, wherein the external friction cone (21a, 21b) is axially supported in the installed position on a cover (29) which is arranged in a fixed position in a groove (30) of the bolt (12).

10. traction drive according to claim 1, in which for sealing the annular space (14) on both sides of the rotary bearing (8) an elastic seal (31) is provided, which is inserted in each case in a frontally and radially inwardly open recess of the lever (10) and which is supported on the opposite side of the cover (29).

11. traction drive according to claim 1, provided with a rotary bearing (8), in which both the damping device (16) and a spring means (33) is integrated.

12. traction drive according to claim 11, wherein the designed as a torsion spring biased spring means 33 is inserted in the rotary bearing (8), which triggers a force component to increase the bias of the traction means (2).

13. traction mechanism drive according to claim 1, in which a starter generator is provided as the pivotable drive member (5) which simultaneously takes over the function of the tensioning device.