WO2017036471A1

WO2017036471A1 - Mechanical tensioner for a primary drive

Info

Publication number: WO2017036471A1
Application number: PCT/DE2016/200362
Authority: WO
Inventors: Johanna Mayer; Christopher Krawietz; Christian Hartmann; Klaudyna OSTERMAIER; Lajos Farkas
Original assignee: Schaeffler Technologies AG & Co. KG
Priority date: 2015-09-04
Filing date: 2016-08-08
Publication date: 2017-03-09
Also published as: DE102016216489A1

Abstract

The invention relates to a mechanical tensioner (1) for a flexible drive of a drive train, comprising a housing (2), a tensioning piston (3) which is movably accommodated in said housing (2), the tensioning piston (3) being pretensioned by a spring element (4) relative to the housing (2) in a tensioning direction, and a ratchet mechanism (6) having an elastically adjustable locking element (5), by means of which ratchet mechanism the tensioning piston (3) is supported in several locking positions in its axial position counter to the tensioning direction. The tensioning piston (3) and the housing (2) are provided with ratchet structures (7, 8) of the ratchet mechanism (6) into which structures the locking element (5) interlockingly engages in the locking positions. The locking element (5) is connected to the tensioning piston (3) such that it follows a displacement movement of the tensioning piston (3).

Description

Mechanical traction device for primary drive

The invention relates to a mechanical Zugmittelspanner for a Zugmitteltneb a drive train / an internal combustion engine, such as a diesel or gasoline engine of a motor vehicle, such as a motorcycle or a snowmobile, with a housing, a slidably received in this housing

Clamping piston, wherein the clamping piston is biased by a spring element relative to the housing in a clamping direction, as well as with an elastically adjustable locking element locking device by means of which the clamping piston is supported / held in several blocking positions in its axial position against the clamping direction /, wherein the clamping piston and the housing are provided with latching structures of the locking device, in which the locking element engages positively in the locking positions and wherein the locking element is connected to the clamping piston, that it participates a sliding movement of the clamping piston.

Generic prior art is known for example from DE 10 2013 201 445 A1. Herein, a mechanical spring plate tensioner is disclosed, which is provided for a traction mechanism drive of an internal combustion engine. This tensioner has a housing and a piston which can be extended out of the housing and which is prepared for applying pressure to a tensioning rail of the traction mechanism drive. Also, this has a locking device which allows the piston to extend out of the housing, but impedes or prevents retraction, wherein detents or projections are present in the housing, which can be brought into positive engagement with the locking device. The locking device is further designed as a spring.

In such known from the prior art embodiments, it has been found to be disadvantageous that the necessary locking elements are often either relatively precise and therefore expensive to produce, to intervene in the blocking positions in the respectively provided latching structures, or the structure relatively complex with mostly several individual components. This in turn has the disadvantage that the blocking element is often relatively expensive to manufacture.

The present invention therefore has the object to remedy these known from the prior art disadvantages and in particular to provide a Zugmittelspanner available, which should be further simplified in its construction, so that in particular its production can be implemented more cheaply.

This is inventively achieved in that the housing on a radial outer side has a hub-shaped receptacle, wherein the clamping piston has an internal thread, which can be brought into engagement with an adjusting tool in order to position the Zugmittelspanner at an initial assembly.

The housing has on a radial outer side a hub-shaped receptacle, which in turn is directly prepared for receiving a tensioning rail or for direct contact of the traction means, such as the belt or the chain.

The tensioning piston has an internal thread which can be brought into engagement with an adjusting tool / setting tool / adjusting tool in order to position / adjust the tensioning means tensioner in its initial assembly (in a drive train of the motor vehicle / in the traction mechanism drive) / in its spatial position. The internal thread is used in this case for clever positioning of Zugmittelspanners in the traction drive / chain drive of the drive train. The blocking element is connected to the tensioning piston such that it undergoes a displacement movement of the tensioning piston (completely).

As a result, the structure is substantially simplified, with the corresponding latching structures being introduced, for example, directly during a primary forming operation of the tensioning piston or the housing. In particular, the clamping piston or the housing is thus particularly inexpensive to produce. As a result, the production is much easier and cheaper implemented. Further advantageous embodiments are claimed in the subclaims and explained in more detail below.

It is expedient if the clamping piston and the housing are formed / configured directly / directly with the latching structures of the locking device, i. in that the latching structures of the latching device are introduced directly / directly into the tensioning piston and the housing, into which latching structures the blocking element positively engages in the respective blocking positions. As a result, the component cost is further reduced.

Furthermore, it is advantageous if the blocking element is designed as a resiliently deformable in the radial direction spring ring, since then a particularly cost-locking element is implemented. If, furthermore, a first latching structure of the latching device is arranged on an inner peripheral side of the housing, it is designed to save space in particular.

In this context, it is also expedient if the first latching structure is in the form of a plurality of circumferentially extending, mutually axially adjacent (ie, lined up) Rastierausnehmungen (preferably in the form of grooves / circumferential grooves) is formed. Thus, the locking element along the entire circumference of the housing / the clamping piston on the housing and the clamping piston is stable. Are the Rastierausnehmungen also geometrically separated from each other by annular, axially in the clamping direction of the clamping piston ramps, the locking element is defined in the respective blocking position supported with a certain biasing force, and when moving in a further blocking position (seen in the clamping direction) in the axial direction along the ramp defined in the radial direction is compressed. As a result, the blocking element is supported particularly securely in the respective blocking position. In this context, it is also expedient if the ramps each form a support surface extending in the radial direction of the tensioning piston, which supports the blocking element against movement of the tensioning piston against the tensioning direction. Each support surface extends at least in sections in the radial direction and at least in sections along the outer contour of the blocking element. This ensures a particularly stable support.

It is advantageous in addition, when a second latching structure of the locking device is arranged / formed on an outer peripheral side of the clamping piston, since then the locking device is implemented even more space-saving.

In this context, it is also advantageous if the second latching structure in the form of a peripheral circumferential receiving recess (preferably in the form of a groove / circumferential groove) is formed. As a result, the second latching structure is particularly compact.

If the blocking element in the respective blocking positions in the axial direction is received in the receiving recess of the clamping piston so as to be non-displaceable, the blocking element can also be integrated in the clamping piston in a space-saving manner.

In this context, it is further advantageous if the locking device has return recesses. It is particularly advantageous if in each case a return recess which widens in the radial direction relative to the receiving recess or recesses is formed on one end of the first latching structure, in which return recesses the blocking element can relax in the radial direction over the first latching structure, and wherein the blocking element then between the receiving recess and a

Return recess in the clamping piston is axially displaceable. As a result, the tensioning piston can be moved particularly easily into the respective axial position relative to the housing.

Furthermore, it is also advantageous if the clamping piston has an axially extending guide recess, in which a firmly connected to the housing bolt as Protection against rotation of the clamping piston projects relative to the housing. As a result, a secure guidance of the clamping piston is implemented.

In other words, according to the invention, a mechanical tensioning device is thus implemented, which is preferably shaped in the form of a chain tensioner and prepared for a primary drive. In particular, this is prepared for a primary drive of a motorcycle / a snowmobile. The inventive concept is based on the formation of a latching mechanism for a mechanical tensioner. The invention comprises a housing and a piston with grooves / grooves / recesses, which serve as a latching structure.

The invention will now be explained in more detail with reference to figures.

Show it:

Fig. 1 is a perspective view of a longitudinally cut Zugmittelspanners invention according to a preferred embodiment, wherein the section along a tensioning piston and a housing of Zugmittelspanners is performed, whereby the inner structure of this Zugmittelspanners and the leadership of the clamping piston in the housing can be seen, and a detail view of the traction mechanism according to Fig. 1 in longitudinal section in the region of the clamping piston, wherein a locking device for supporting the can be seen in detail.

The figures are merely schematic in nature and are for the sole purpose of understanding the invention. The same elements are provided with the same reference numerals.

The traction mechanism 1 according to the invention is shown in its entirety in FIG. The Zugmittelspanner 1 is designed as a purely mechanical Zugmittelspanner 1 and thus forms no fluidic pressure chamber between its housing. 2 and his tensioning piston 3 off. The Zugmittelspanner 1 is formed / prepared in its operation for tensioning a trained as a chain traction means in an embodiment of the traction mechanism as a chain drive. Alternatively, however, according to a further embodiment, it is also designed / prepared as a belt drive for tensioning a tensioning means designed as a belt in an embodiment of the traction mechanism drive. The traction mechanism is a primary drive of a drive train of a motor vehicle, which is designed as a motorcycle or snowmobile, and rotatably connects an output shaft of an internal combustion engine with another drive shaft, such as a transmission shaft of the drive train for driving the motor vehicle.

The traction means 1 comprises in a conventional manner the housing 2, which receives the clamping piston 3 within a cylindrical guide recess 18 in its axial direction which is formed here coaxially to the axial direction of the guide recess 18 slidably. The clamping piston 3 is thereby displaceably mounted to the housing 2. The guide recess 18 is introduced as an axial bore in the housing 2. The clamping piston 3 is so matched with its outer peripheral side 14 on an inner peripheral side 1 1 of the housing 2 / the guide recess 18 that it is guided in its axial direction by means of a sliding / clearance fit. The tensioning piston 3 projects out of the housing 2 at a first end 26 of the guide recess 18, at which the guide recess 18 opens toward the environment.

The tensioning piston 3 is biased during operation in a tensioning direction which corresponds to an extension direction of the tensioning piston 3 out of the housing 2 beyond the first end 26. This bias of the clamping piston 3 relative to the housing 2 is realized by a spring element 4. The spring element 4 is designed as a helical compression spring. Also, the spring element 4 is inserted in an intermediate space 27 between the housing 2 and the clamping piston 3 in the region of the guide recess 18, which intermediate space 27 is always axially spaced from the first end 26 during operation. The spring element 4 is supported on an end face facing away from the clamping direction of the clamping piston 3 and on the housing 2. Also, the intermediate space 27, in which the spring element 4 is received, on reason of the execution of Zugmittelspanners 1 as a mechanical Zugmittelspanner 1 open to the environment / depressurized.

For rotationally secured displacement of the clamping piston 3 relative to the housing 2, a piston anti-rotation device 19 is also formed. This anti-piston device 19 is arranged between the housing 2 and the clamping piston 3 such that the clamping piston 3 is secured against rotation relative to the housing 2 in its axial direction is displaceable. The piston anti-rotation device 19 has in this embodiment a bolt 17 which anchored on the one hand in the housing 2 / fastened, namely preferably (screwed) is pressed, and on the other hand in an elongated, in the axial

Direction of the clamping piston 3 extending guide groove in the form of a guide recess 16 of the clamping piston 3 extends into it. The bolt 17 extends in the radial direction of the clamping piston 3 and protrudes in the radial direction from the outside inwards into the guide recess 16, under the rotation-proof support of the clamping piston 3 relative to the housing 2.

The clamping piston 3 is still hollow. The clamping piston 3 is thus also referred to as a hollow piston. Consequently, the clamping piston 3 has an axially extending inner hole 20 which extends coaxially to its longitudinal axis. This inner hole 20 is designed here as a bore. On an inner peripheral side of the

Tensioning piston 3 / of the inner hole 20 is an internal thread 9 is attached. This internal thread 9 serves for positive and positive reception of an adjusting tool not shown here for clarity (preferably a threaded rod or a tool having a threaded rod) for simple positioning of the traction mechanism 1 in the traction mechanism / relative to the traction mechanism in the initial assembly of Traction device tensioner 1.

Furthermore, the Zugmittelspanner 1 on a locking device 6. This locking device 6 is formed with a first latching structure 7, which is formed on an inner peripheral side of the housing 1 1 1 / integral / stoffeinteilig, a second

Locking structure 8, which is integrally / directly / stoffeinteilig formed on an outer peripheral side 14 of the clamping piston 3, and a (separately formed to the first and the second latching structure 7, 8) locking element 5 equipped / formed. The Rastiereinrichtung 6 is provided in the usual manner for supporting the clamping piston 3 against its clamping direction / against its extension direction out of the housing 2 out / in its direction of retraction into the housing 2 in / designed. The latching structures 7 and 8 form positive receptacles for the blocking element 5, which engages positively in the respective blocking position of the clamping piston 3 relative to the housing 2 in these two latching structures 7 and 8 and thus the clamping piston 3 in the axial direction relative to the housing 2 in this Entry direction defines / supports / blocks. The exact structure of the locking device 6 is particularly well visible in Fig. 2. The first latching structure 7 is formed by a plurality of latching recesses 12 extending in the form of circulating grooves extending along the circumference / in the circumferential direction of the inner circumferential side 11. The Rastierausnehmungen 12 are strung together in the axial direction and in each case by ramp-shaped elevations, the ramps 13, geometrically separated from each other. Between each two adjacent ones

Rastierausnehmungen 12 is always a ramp 13 is arranged, which also rotates in the circumferential direction. The ramp 13 has on a (axial) side, which is directed in the retraction direction of the clamping piston 3, a smaller pitch than on another (axial) side, which is directed in the extension direction of the clamping piston 3.

The blocking element 5 is designed as a spring ring 10, which is arranged in the radially outward biased between the clamping piston 3 and the housing 2. The spring ring 10 is arranged such that it is biased biased in a clamping state of the Zugmittelspanners 1 / of the clamping piston 3 in the radial direction of the clamping piston 3 in the respective Rastierausnehmungen 12 in the respective axial position / locking position. Each ramp 13 forms a support surface 21, which extends annularly and extends partially in the radial direction to the outside. In addition, the blocking element 5 is received in a form-fitting manner in the axial direction of the clamping piston 3 in the clamping state in a receiving recess 22 which is introduced on an outer peripheral side 14 of the clamping piston 3 as a groove.

The support surface 21 extends at least in a radially inner region in the radial direction in such a way that the blocking element 5 by means of this support surface 21 in the Ein- driving direction of the clamping piston 3 is supported in the blocking positions. As a result, an extension of the clamping piston 3, ie a movement of the clamping piston 3 in its extension in the normal operating state (the clamping state) of Zugmittelspanners 1 / the locking device 6 allows, whereas a retraction, that is a retraction of the clamping piston 3 is blocked by the locking device 6.

In addition to the receiving recess 22 which receives the locking element 5 in this clamping state form fit, is in the clamping piston 3, in turn on its outer circumferential side 14 axially adjacent the receiving recess 22 a

Return recess 15 attached. This return recess 15 is also formed as a circumferential groove / annular groove and spatially / geometrically separated by a web 23 of the receiving recess 22.

In Fig. 2, the locking element 5 is inserted in a clamping state of the locking device 6 / of Zugmittelspanners 1 in the receiving recess 22 of the clamping piston 3. For reshuffling, i. for displacing the tensioning piston 3 in its retraction direction, not only the tensioning piston 3 has a return recess 15, but also the housing 2, which return recesses of the housing 2 are identified by the reference numerals 28a and 28b. A first

Rückführausnehmung 28a of the housing 2 is introduced at a first axial end portion of the first latching structure 7 to this subsequent to the inner peripheral side 1 1. A second return recess 28b is arranged at a second end region of the first latching structure 7 opposite the first axial end region. Both recirculation recesses 28a, 28b are formed substantially the same and again in the form of circumferential recesses / grooves. Only the two Rückführausnehmungen 28a, 28b further in the radial direction outwards, ie have a larger (inner) diameter than the individual Rastierausnehmungen 12 of the first latching structure 7. The web 23 on the clamping piston 3 is selected in its outer diameter and on matched the housing 2, that the clamping piston 3 in the clamping state (ie, in a positioning of the locking element 5 in the receiving recess 22) in an axial region of the first latching structure 7 not against the extension direction and the blocking element 5 can not be displaced into the return recess 15, whereas the tensioning piston 3 can be moved counter to the extension direction in the restoring state (ie when the blocking element 5 is positioned in the return recess 15) in an axial region of the first latching structure 7.

For switching between the clamping state and the reset state serve the two return recesses 28a, 28b in the housing 2. If the clamping piston 3, for example. Fully extended, locks the locking element 5 in the radial direction outwardly into the first return recess 28a and is in its scope due the elastic preload extended outwards / expanded independently. As a result, with a displacement of the tensioning piston 3 in its retraction direction, the tensioning piston 3 can be displaced relative to the blocking element 5 until the blocking element 5 finally comes into contact with the tensioning piston 3 in the axial region of the return recess 15. If the blocking element 5 is arranged in this return recess 15, the tensioning piston 3 is in turn moved back in its retraction direction, so that it can be pushed completely into the housing 2 in the axial direction due to the formation of the return recess 15 until, in turn, the blocking element 5 at the axial height the second return recess 28b is located. Then the locking element 5 snaps in the radial direction outwards into the second

Return recess 28b into it and the clamping piston 3 can in turn be moved relative to the locking element 5, that the locking element 5 is moved back into the receiving recess 22 back. Thus, when extending the tensioning piston 3, the blocking element 5 is located in the latching groove / receiving recess 22. Upon complete extension of the clamping piston 3, the blocking element 5 is pushed into the first switching groove / first return recess 28a. When pushed back, the web pushes 23 "under" the locking element 5 and the locking element 5 is taken by the board of the groove / Rückführausenehmung 15. Das Zugmittelspanner is due to the starting position As it moves out, the web 23 pushes "under" the blocking element 5 and the blocking element 5 is entrained by the board of the receiving recess 22. In Fig. 1 it is also seen that the housing 2 has a hub-shaped receptacle 25 on a radial outer side, which in turn is directly prepared for receiving a tensioning rail or for direct contact of the traction means, such as the belt or the chain.

In other words, according to the invention, a mechanical chain tensioner (Zugmittelspanner 1) implemented, the necessary bias is applied by a spring (spring element 4) which presses on the piston (clamping piston 3), wherein a drop of the piston 3 (in its retraction direction) is prevented by the latching steps (Rastierausnehmungen 12). There is no fluidic / hydraulic damping, since no oil supply is applied to the chain tensioner 1. The chain tensioner 1 can be used for various gear ratios of the drive train by being screwed at the initial position to the appropriate position. For this purpose, the piston 3 has an internal thread 9. In this way, the chain tensioner 1 / the tensioning piston 3 can be screwed onto an adjusting tool embodied as a threaded rod and be positioned in an initial position. Due to this positioning property of the chain tensioner 1 is carried out against rotation per se, whereby the assembly facilitates and twisting during operation is prevented. The internal thread 9 does not serve to secure the chain tensioner 1 against twisting, but rather the anti-rotation protection is carried out by the anti-piston device 19.

Reference sign list Traction device tensioner

casing

clamping piston

spring element

blocking element

locking device

first latching structure

second latching structure

inner thread

spring washer

Inner circumferential side

Rastierausnehmung

ramp

Outer peripheral side

Return recess of the clamping piston guide recess

bolt

guide recess

Piston rotation

inner hole

supporting

receiving recess

web

admission

first end

gap

a first return recess of the housing B second return recess of the housing

Claims

Patent claims

Mechanical traction tensioner (1) for a traction mechanism of a drive train, with a housing (2), one in this housing

(2) slidably accommodated clamping piston (3), the clamping piston

(3) by means of a spring element

(4) is biased in a clamping direction relative to the housing (2), and a locking device (6) having an elastically adjustable locking element (5), by means of which the clamping piston (3) is supported in several locking positions in its axial position counter to the clamping direction , wherein the clamping piston (3) and the housing (2) are provided with locking structures (7, 8) of the locking device (6), into which the locking element (5) engages in a form-fitting manner in the locking positions and the locking element (5) is thus on the Clamping piston (3) is connected so that it follows a displacement movement of the clamping piston (3), characterized in that the housing (2) has a hub-shaped receptacle (25) on a radial outside, the clamping piston (3) having an internal thread (9) which can be brought into engagement with an adjusting tool in order to position the traction tensioner (1) during initial assembly.

Traction tensioner (1) according to claim 1, characterized in that

Locking element (5) is designed as a spring ring (10) which is elastically deformable in the radial direction.

Traction tensioner (1) according to one of claims 1 to 2, characterized in that a first latching structure (7) of the latching device (6) is arranged on an inner circumferential side (1 1) of the housing (2).

Traction tensioner (1) according to claim 3, characterized in that the first latching structure (7) is designed in the form of a plurality of latching recesses (12) running in the circumferential direction and arranged axially adjacent to one another.

5. Traction tensioner (1) according to claim 4, characterized in that the

Locking recesses (12) are each geometrically separated from one another by annular ramps (13) which rise axially in the clamping direction.

6. Traction tensioner (1) according to one of claims 1 to 5, characterized in that a second latching structure (8) of the latching device (6) is arranged on an outer peripheral side (14) of the tensioning piston (3).

7. Traction tensioner (1) according to claim 6, characterized in that the second latching structure (8) is designed in the form of a circumferentially circumferential receiving recess (22).

8. Traction tensioner (1) according to claim 7, characterized in that

Locking element (5) is accommodated in the locking positions in the axial direction in a non-displaceable manner in the receiving recess (22) of the clamping piston (3).

9. Traction tensioner (1) according to one of claims 1 to 8, characterized in that the tensioning piston (3) has an axially extending guide recess (16) into which a bolt (17) firmly connected to the housing (2) is inserted to prevent the device from rotating Clamping piston (3) protrudes relative to the housing (2).