DE102017127810A1 - Clamping device with adjusting device - Google Patents

Abstract

The present invention relates to a tensioning device, in particular for a timing chain of an internal combustion engine, with a tensioner housing, a guided in a piston bore of the tensioner housing clamping piston, and an adjusting device for gradually adjusting the working range of the clamping piston, wherein the adjusting device on the front in the clamping direction of the clamping piston arranged latching profile and engaging in the locking profile locking element comprises. The locking element is formed as a slotted locking ring and the locking profile of the clamping piston has at the front end in the clamping direction an insertion groove, in which during assembly of the clamping piston in the piston bore of the locking ring (36) is arranged captive and compressible. The piston bore of the tensioner housing has at the front end in the clamping direction a flat insertion cone with an angle of inclination to the piston bore of 5 ° to 25 °, preferably an inclination angle between 10 ° and 20 °, in order to mount the clamping piston in the piston bore by means of a force center and compress the locking piston in the insertion groove of the tensioning piston and to introduce the locking ring thus arranged in the insertion groove into the piston bore. Furthermore, the invention relates to a chain drive, in particular a timing chain drive of an internal combustion engine, with such a tensioning device.

Description

The present invention relates to a tensioning device, in particular for a timing chain of an internal combustion engine, with a tensioner housing, a guided in a piston bore of the tensioner housing clamping piston, and an adjusting device for gradually adjusting the working range of the clamping piston, wherein the adjusting device on the front in the clamping direction of the clamping piston arranged latching profile and engaging in the locking profile locking element comprises. Furthermore, the invention relates to a chain drive, in particular a timing chain drive of an internal combustion engine, with such a tensioning device.

Such tensioning devices are widely used in the art and are used in particular as chain tensioners in timing chain drives of internal combustion engines. As a rule, these clamping devices comprise a housing with a piston bore in which a tensioning piston prestressed by means of a compression spring is arranged. The usually hollow cylindrical clamping piston forms with the piston bore of the housing a pressure chamber which is filled to dampen the retraction movement of the clamping piston with a hydraulic fluid. This pressure chamber is connected via a check valve to a hydraulic circuit, for example the engine oil circuit of the internal combustion engine, in order to replace the hydraulic fluid escaping from the pressure chamber, which leaks out of the pressure chamber via a leakage gap formed between piston and clamping piston or a corresponding venting bore. Known tensioning devices often have adjusting devices in the form of latching mechanisms which define a free working range of the tensioning piston between a blocking and skipping position, whereby too deep retraction of the tensioning piston into the piston bore, for example when starting the internal combustion engine, prevents the blocking position, but an adjustment the working range of the tensioning piston, for example when chain wear, is made possible.

Conventional adjusting devices for such clamping devices have on the clamping piston on a lateral detent, which cooperates with a corresponding locking element. The prestressed in the radial direction of the clamping piston locking element allows over the force applied by the strong bias of the spring element force, skipping the clamping piston in the clamping direction and simultaneously prevents relatively hard and strong vibration shocks too far retraction of the clamping piston in the piston bore of the housing. Such a clamping device is from the DE100 14 700A1 in which a tensioning piston is provided with a lateral sawtooth profiling, in which a ratchet block engages through a window opening in the housing. The free working range of the tensioning piston is limited in this tensioning device by the axial freedom of movement of the ratchet block in the housing window.

In contrast, the tensioning piston in the DE 196 80 418 C1 disclosed hydraulic clamp on a plurality of axially spaced circumferential locking grooves, wherein on the clamping piston a locking clasp is pushed, which engages in the locking grooves. For gradual readjustment of the working range of the clamping piston, a lateral cutout is provided on the housing, which merges into a groove in the region of the piston bore. After mounting the clamping piston, a stop ring is used at the exciting end of the piston bore, which defines the jump stop of the adjusting device and thus limits the free working range of the clamping piston.

Also the publication DE 10 2011 101 865 A1 shows a clamping device with a locking clasp, which is arranged in a circumferential groove in the piston bore and rests resiliently against the circumferential locking profile of the clamping piston. About a lateral cutout, the at least partially circular detent profile can be expanded for mounting the tensioning piston. Between the detent profile of the tensioning piston and the tension-side end, a rectangular groove is provided in this embodiment in which a transport locking pin holds the tensioning piston in its transport position.

A generic clamping device is from the DE 10 2015 013 121 A1 known, wherein the extendable from the piston bore of the tensioner housing tensioning piston on the tension-side end has a locking profiling on which a locking clasp is seated with two circular section-shaped clamping portions under spring tension. The two circular-segment-shaped clamping sections extend laterally into two angled stop wings which engage behind from the outside behind corresponding stop projections on the tensioner housing, in order to limit the free working travel of the tensioning piston and to enable a return of the locking device.

Conventional clamping devices with adjusting devices for limiting the retraction movement of the clamping piston in the tensioner housing are widely used and have proven themselves in the field. The corresponding constructions of the adjusting devices are stably constructed to ensure a safe function over the life of the clamping device. In addition to a special, tailored to the particular application construction of the locking element, with correspondingly high costs for bending special wire braces in small numbers, the reworking of the tensioner housing for introducing necessary access openings by additional processing and action steps is very labor-intensive and costly. In addition to the individual and expensive production of the necessary components, a complex, error-prone mounting of the adjusting device and the provision of a transport lock are also common in conventional fixtures beyond.

The variety of known in the art tensioning devices allows the use of jigs with adjusting devices, which are aligned with a corresponding embodiment to the particular application. In addition to the necessary individual tensioner concepts and the complex structure of the adjusting device, as well as the resulting effort in the manufacture and assembly of components, there is a continuous development pressure to improve and optimize components and their by the progressive innovation of internal combustion engines in the automotive industry Integration into increasingly complex internal combustion engines. Further, in the automotive industry, hydraulically-actuated jigs are being developed for corresponding engine series, so that there is a constant need for optimizing the existing designs in view of the relatively large number. In addition, tensioning devices actively act on the timing drive or other aggregate drives of the internal combustion engine and negatively influence the energy balance of the internal combustion engine via the friction in the drives, but their optimization represents a constant task of the automobile manufacturers and their suppliers.

The present invention is therefore an object of the invention to provide a clamping device with an adjusting device, the construction of a safe operation by the simplest possible design and installation of the clamping device, a cost-effective production and production and energy-saving operation allows.

This object is achieved in a generic clamping device according to the invention in that the locking element is formed as a slotted locking ring, the locking profile of the clamping piston at the front end in the clamping direction has an insertion, in which during assembly of the clamping piston in the piston bore of the locking ring completely captive and compressible is arranged, and the piston bore of the tensioner housing at the front end in the clamping direction has a flat insertion cone with an inclination angle to the piston bore of 5 ° to 30 °, preferably an angle of inclination between 10 ° and 25 ° in order to install the clamping piston in the piston bore means a force on the clamping piston to center the locking ring in the insertion groove and to compress and to introduce the thus arranged in the insertion groove locking ring in the piston bore. The slotted locking ring, which is at least predominantly circular in shape, is axially and radially centered in the insertion groove during assembly of the tensioning device by the flat insertion cone so as to prevent tilting or damage of the slotted locking ring. In contrast to the known from the prior art circlips that fix as a part of a transport lock the clamping piston once in a transport and mounting position in the piston bore, which is used here as a locking element of the adjusting slotted locking ring for continuous use over the entire life of Tensioning device formed, and not only for a single use, so that a possible malfunction and failure during the period of operation of the clamping device is avoided by the optimized, damage-free arrangement of the slotted locking ring in the insertion groove. In contrast to conventional adjusting devices, in which a locking element designed as a locking clasp extends over corresponding cutouts in the tensioner housing to the outside, or which can be gripped and relaxed via corresponding cutouts in the tensioner housing arranged in the piston bore locking element from the outside for mounting the tensioning piston, enables the inventive design of the tensioning device in the region of the piston bore, at least at the clamping end, a rotationally symmetrical design of the tensioner housing, and the use of a simple annular locking element without additional bends attached. The maximum utilized contact area between the locking partners results in an optimal power distribution in the blocking position.

The at least in the region of the piston bore rotationally symmetrical tensioner housing can be inexpensively manufactured as a rotating part, which can be on one-sided cutouts for performing or engaging in locking elements, which must be fitted in a separate time-consuming operation and in addition require a downstream deburring can be dispensed with. The flat introduction cone, which allows a low in the axial and radial direction uniform compression and centering of the locking ring in the insertion via the low inclination angle to the piston bore of 5 ° to 30 °, is arranged in the transition of the piston bore to the clamping side end of the tensioner housing and formed accordingly as an outer cone which tapers against the tension direction. Here sits the circular section-shaped slotted Locking ring prior to assembly of the clamping piston in the piston bore loosely in the insertion groove, which is arranged adjacent to the tension-side head of the clamping piston and merges against the clamping direction in the locking profile. In contrast to conventional adjusting devices, only a force is applied to the clamping piston in the clamping device according to the invention during assembly of the clamping piston without requiring additional mechanical action on the locking element or to align the individual parts of the adjusting previously.

An expedient embodiment provides that the depth of the insertion groove is greater than the radial ring thickness of the locking ring minus the width of the gap between the clamping piston and the piston bore. Such a depth of the insertion groove allows easy and obstacle-free insertion of the arranged in the insertion groove locking ring in the piston bore. The ring thickness is to be understood as meaning the material thickness of the locking ring in the radial direction, i. the diameter of a round wire material or the radial strip thickness in a rectangular material. Since the base of the insertion groove does not necessarily have to be flat in the axial direction, or parallel to the cylinder peripheral surface, but for example has a shape adapted to the locking ring, the depth of the insertion groove is to be understood as the maximum depth of the insertion groove in the radial direction. Further, the depth of the insertion groove refers to the undisturbed cylinder peripheral surface of the clamping piston, which also determines the gap against the undisturbed piston bore at the same time. Preferably, the depth of the insertion groove may be between 1.0 times and 2.65 times the variable ring thickness of the locking ring. In this area, both damage to the slotted locking ring during assembly of the clamping piston is excluded in the piston bore still is a change in shape of the slotted locking ring by over-compressing the locking ring possible.

A favorable design provides that the slotted locking ring is formed as a round wire ring and made of a spring wire steel, preferably a conventional Runddrahtsprengring is. A round wire ring allows a simple bend and the manufacture of spring steel, the necessary properties of the slotted locking ring to sit in operation with an at least slight bias on the locking profile, but to be arranged loosely in the insertion, in spite of an introduction on the tension-side opening of the Piston bore to be pushed according to the adjustment of the work area on the locking profile. The production of round wire rings made of spring steel is well known in the art and is used for the production of conventional round wire snap rings. Advantageously, a conventional round wire snap ring manufactured according to DIN 7993 can be used directly, which can be provided in a very cost-effective manner, in contrast to the application-related locking rings produced in relatively small numbers. The wire diameter of the round wire snap rings in question for a tensioning device according to the invention is between 0.6 to 2.0 mm, preferably between 0.8 to 1.3 mm, and ideally 1.0 mm. With small wire diameter increases the risk that the slotted locking rings already bend during handling in the assembly preparation, while larger diameters with the rigidity of the locking ring required during assembly of the clamping piston but also in the adjustment of the working area force on the clamping piston strong increases, in addition to the problem that with larger diameters and the radial space increases and thus increase the size of the clamping device.

A further embodiment provides that the unloaded opening width of the slotted locking ring is 1.5 to 5.0 times, preferably 2.5 to 4.0 times the radial ring thickness of the locking ring. The smaller the unloaded opening width of the slotted locking ring, and thus the larger the closed circular section circumference of the locking ring the more uniformly can the slotted locking ring center during assembly of the clamping piston by the flat insertion cone in the introduction and the more uniform the movement of the slotted locking ring on the Locking profile for the stepwise adjustment of the working area of the tensioning piston. In this case, it makes sense that the unloaded opening width does not exceed 5 times or 4 times the radial ring thickness of the locking ring in order not to negatively influence this function of the slotted locking ring. When using conventional round wire snap rings according to DIN 7993, the usual tolerances for the unloaded outer diameter of the round wire snap ring +/- 0.3 mm, so that in a suitable round wire snap ring for a clamping device according to the invention, the opening width between about 3.0 mm and maximum 9.0 mm.

A particular variant of the inventive clamping device provides that the length of the flat insertion cone in the longitudinal direction of the piston bore is greater than the ring thickness of the locking ring, preferably between 1.5 and 5.0 times the radial ring thickness of the locking ring. This allows a smooth, slow centering of the locking ring to secure compression of the locking ring in the insertion groove.

A useful embodiment provides that the locking profile of the clamping piston has a plurality of locking grooves, wherein between the clamping direction in the front end of the clamping piston arranged insertion groove and a first adjacent locking groove a flat activation cone is provided, with an inclination angle to the clamping piston axis of 10 ° to 30 °, preferably an inclination angle of 15 ° and 25 °. The circumferential on the circumference of the clamping piston locking grooves for adjustment of the working area have a slotted locking ring adapted profiling, wherein when using a round wire ring, the clamping side end of the locking groove is circular section-shaped and has a depth in about the quarter to half radial ring thickness of the locking ring equivalent. At the opposite end in the retraction of the clamping piston an adjusting cone is formed, which extends from the circular portion-shaped depth range of the locking groove to undisturbed cylinder peripheral surface of the clamping piston and allows widening of the slotted locking ring and slipping in the subsequent locking groove for the stepwise adjustment of the working range of the clamping piston. The activation cone may extend partially or completely over the bottom of the insertion groove.

Between the arranged in the clamping direction at the front end of the clamping piston insertion groove and the locking grooves, a flat activation cone is provided which allows a uniform and radially centered expansion of the locking ring and a locking of the locking ring in the first locking groove of the locking profile during commissioning of the clamping device. After loosening a transport lock, for example, arranged at the retracting end of the clamping piston in a securing profile circlip presses a, arranged in the piston bore between tensioner housing and clamping piston compression spring, the clamping piston from the piston bore, wherein the loosely arranged in the insertion groove locking ring of a projection of the tensioned groove wall of a circumferential groove in the piston bore is pushed over the flat activation cone, wherein the slotted locking ring radially centered on the flat activation cone and expanded against a bias of the locking ring, so as to slide in the first locking groove of the locking profile. It should be noted that the distance between the, the locking piston facing edge of the clamping groove side wall and the outer diameter of the locking contour of the piston must not be greater than 25% of the locking ring diameter. Since the angle of inclination of the flat activation cone relative to the clamping piston axis is only between 10 ° and 30 °, even a relatively small spring force of the compression spring is sufficient to transfer the slotted locking ring from its transport position in the insertion groove in an activation position on a first adjacent locking groove of the locking profile ,

Appropriately, a circumferential circumferential groove is provided at the tension end of the piston bore near the flat introduction cone. The circumferential groove defines together with the engaging in the locking profile locking ring the free path of the clamping piston. The groove wall formed on the tension-side end of the circumferential groove extends substantially perpendicularly or at a relatively large angle to the tensioning piston axis in order to displace the locking ring arranged on the locking profile of the tensioning piston against the tensioning direction on the locking profile. The opposite groove wall, i. formed in the retraction direction of the clamping direction groove wall, has an inclination angle to the clamping piston axis of 20 ° to 60 °, preferably 45 °, to secure at a too wide retraction of the clamping piston in the piston bore the locking ring on the locking profile and further retraction of the clamping piston to prevent. Since the circumferential groove during the movement of the locking ring on the locking profile on the clamping piston must also accommodate the resting on the undisturbed cylinder peripheral surface of the clamping piston locking ring, the depth of the circumferential groove relative to the piston bore is greater than the radial ring thickness of the locking ring minus the width of the gap between clamping piston and piston bore , preferably between 1.0 times and 1.5 times the radial ring thickness of the locking ring.

A modification provides that the clamping device is designed as Einschraubspanner. A Einschraubspanner is relatively easy to produce as a turned part and requires no post-processing of unbalanced device parts. Further, a Einschraubspanner allows a simple and secure installation of the clamping device on an internal combustion engine. Alternatively, the clamping device can also be designed as a flange clamp or as a tensioner cartridge for a flange housing.

Furthermore, the present invention relates to a chain drive, in particular a timing chain operation of an internal combustion engine, with a drive sprocket at least one output sprocket, the drive sprocket and the at least one output sprocket interconnecting drive chain and a drive chain exciting tensioning device according to one of the embodiment described above. Due to the special design of the clamping device of this chain drive despite a simple and inexpensive construction in addition to its usual functions in addition a secure bias of the drive chain with a safe adjustment functions for gradually adjusting the working range of the clamping piston and to limit the Enable retraction. Accordingly, with such a system, a strong rattling chain drive and skipping of the drive chain can be surely prevented. In addition, the clamping device according to the invention requires only a compression spring with a low spring force, since only a small spring force is necessary both for securing the clamping device in a transport position and for the activation of the adjusting device. In contrast to the compression springs used in conventional tensioning devices with a spring force of about 120 N compression springs can be used in the tensioning device according to the invention without limiting the function, which apply a much lower spring preload on a chain drive with a spring force of 20 to 80 N. Due to the lower spring force buckling in the radial direction is prevented, whereby a possible material removal on the compression spring and the piston inner side can be excluded. Since the friction in a chain drive also depends strongly on the tensioning the drive chain tensioning device, the use of a tensioning device according to the invention in a corresponding chain drive can lead to a reduction of friction by up to 10%, which implies a corresponding fuel economy.

• 1 einen Kettentrieb für einen Verbrennungsmotor gemäß der vorliegenden Erfindung,
• 2 eine perspektivische Ansicht der erfindungsgemäßen Spannvorrichtung aus 1,
• 3 eine vergrößerte Schnittansicht der erfindungsgemäßen Spannvorrichtung aus 1,
• 4 eine vergrößerte Ausschnittsansicht des spannseitigen Endes der erfindungsgemäßen Spannvorrichtung aus 1,
• 5a bis d Ausschnittsansichten des spannseitigen Endes der erfindungsgemäßen Spannvorrichtung aus 1 in unterschiedlichen Montage- und Betriebsstellungen, und
• 6a und b vergrößerte Ausschnittsansicht des spannseitigen Endes der erfindungsgemäßen Spannvorrichtung aus 1 zur Darstellung der Funktion der Nachstelleinrichtung.

In the following, an embodiment of the present invention will be explained in more detail with reference to drawings. Show it:

• 1 a chain drive for an internal combustion engine according to the present invention,
• 2 a perspective view of the clamping device of the invention 1 .
• 3 an enlarged sectional view of the clamping device according to the invention 1 .
• 4 an enlarged sectional view of the tension-side end of the clamping device of the invention 1 .
• 5a to d sectional views of the tension-side end of the tensioning device according to the invention 1 in different assembly and operating positions, and
• 6a and b is an enlarged detail view of the tension-side end of the tensioning device according to the invention 1 to illustrate the function of the adjusting device.

In 1 is a chain drive 1 represented for an internal combustion engine. This designed as a timing chain drive chain drive 1 includes two overhead drive sprockets 2 for driving the camshafts, a bottom driven by the crankshaft drive sprocket 3 and an endless drive chain running around it 4 , In the load area of the chain drive 1 is a guide rail 5 arranged at the the drive chain 4 along slides.

On the opposite slack side of the chain drive is a pivotally mounted clamping rail 6 provided in the vicinity of the crankshaft drive sprocket 3 is pivotally mounted and by means of a clamping device 7 to the drive chain 4 is pressed in order to operate in the absence of the chain drive 1 pretension. The tensioning device 7 is in the present embodiment in 1 designed as a Einschraubkettenspanner in the engine block 8th of the internal combustion engine is screwed in and on the pressure range 9 the tensioning rail 6 imprints, with a predetermined force of the tensioning device 7 to the drive chain 4 is pressed. Alternatively, the tensioning device 7 Also be designed as a flange clamp or as a tensioner cartridge with flange housing, which with appropriate fasteners on the engine block 8th is flanged.

The perspective side view of the clamping device 7 in 2 shows the essentially. Rotationally symmetrical structure of this Einschraubkettenspanners. This tensioning device 7 includes a tensioner housing 10 and a tensioning piston 12 , at the tension end of the tensioner housing 10 protrudes from this. On the outer circumference of the tensioner housing 10 is a threaded section 22 provided with this Einschraubkettenspanner in the engine block 8th can be screwed. At one of the tensioning piston 12 opposite end of the tensioner housing 10 is a flange 23 and a hexagon 24 provided to the tensioning device 7 in the engine block 8th screwed. The flange 23 lies, as well as in 1 shown on the engine block 8th on, with a sealing ring 25 the tensioning device 7 to the engine block 8th seals off. Next is between the threaded portion 22 and the flange 23 an opening 26 provided by which the tensioning device 7 is supplied with engine oil.

An enlarged sectional view of the clamping device 7 is 3 presents. The tensioner housing 10 has a cylindrical piston bore 11 on, in which the hollow cylindrical clamping piston 12 along its clamping piston axis A is guided in the longitudinal direction movable. Between the hollow cylindrical clamping piston 12 and the piston bore 11 the tensioner housing 10 is a pressure room 13 formed by a check valve 14 at the bottom of the piston bore 11 and one between the opening 26 on the circumference of the tensioner housing 10 and the check valve 14 extending supply channel 15 is connected to the engine oil circuit of the internal combustion engine. The tensioning piston 12 is with one in the pressure room 13 arranged helical compression spring 16 biased in the longitudinal direction and presses the tensioning piston 12 in the direction of the clamping piston axis A against the pressure area 9 the tensioning rail 6 to get over the tensioning rail 6 the drive chain 4 in chain drive 1 pretension. In the tension end of the hollow cylindrical clamping piston 12 is still a filler 19 provided the volume of the pressure chamber 13 reduces and at the same time the compression spring 16 leads. Next is the frontal vent hole 17 in the clamping piston head 34 of the tensioning piston 12 through the filler 19 opposite to the pressure chamber filled with engine oil 13 throttled sealed. For this purpose, the head of the mushroom-shaped filling body 19 by means of the compression spring 16 that is against the check valve 14 at the bottom of the piston bore 11 supported, from the inside against the clamping end of the clamping piston 12 pressed. About the vent hole 17 is at a retraction movement of the clamping piston in the piston bore 11 the tensioner housing 10 Engine oil throttled delivered. Between the cylinder wall of the clamping piston 12 and the piston bore 11 in the tensioner housing 10 is a gap 18 formed by the retraction of the tensioning piston 12 into the piston bore 11 also engine oil from the pressure chamber 13 can escape. This gap 18 Depending on the requirements of the throttle behavior of the clamping device 7 as well as the manufacturing tolerances of the tensioner housing 10 and the tensioning piston 12 between 15 and 75 microns, for modern combustion engines, a range of 3 to 30 microns for the gap 18 to be sought. Between the tensioning piston 12 and the tensioner housing 10 can continue a transport security 21 be provided after an assembly of the clamping piston 12 in the piston bore 11 the tensioner housing 10 the tensioning piston 12 in a transport position, and which is not described in detail here.

The enlarged sectional view of the clamping device 7 in 3 shows at the bottom of the piston bore 11 a valve seat 20 for receiving the check valve 14 as well as the supply channels 15 to the inlet of engine oil through the opening 26 , The check valve 14 is by the compression spring 16 in the valve seat 20 pressed and thereby sealed. At the tension end of the piston bore 11 and the tensioning piston 12 is an adjustment device 27 provided, an adjustment of the working range of the clamping device 7 allows, as well as too far retraction of the clamping piston 12 into the piston bore 11 prevented. This is at the front in the clamping direction of the clamping piston 12 a locking profile 30 provided with several radially circumferential locking grooves 31 , one on the locking profile 30 seated and in the Rastnuten 31 engaging locking element 28 and one in the piston bore 11 the tensioner housing 10 at the front in the clamping direction of the piston bore 11 arranged circumferential groove 29 in which the on the locking profile 30 seated locking element 28 in the free working area of the tensioning piston 12 can move.

4 shows an enlarged sectional view of the clamping end of the clamping device 7 out 3 before mounting the tensioning piston 12 into the piston bore 11 the tensioner housing 10 , In this enlarged view is clearly the adjacent to the clamping piston 12 circumferential locking grooves 31 the locking profile 30 to recognize. The circumferential groove 29 has a substantially perpendicular to the clamping piston axis A aligned clamping side groove wall 32 and one to the clamping piston axis A inclined trained engagement groove wall 33 on. This as a slotted locking ring 36 trained locking element 28 the adjusting device 27 sits in one between the tension-side head 34 of the tensioning piston 12 and the Rastnuten 31 the locking profile 30 arranged introduction groove 35 , wherein the slotted locking ring 36 loose in the insertion groove 35 is arranged and in the radial direction relative to the outer periphery of the clamping piston 12 survives. Here is the maximum depth of the insertion groove 35 greater than the radial ring thickness of the locking ring 36 , The groove bottom of the insertion groove 35 can instead of a straight, parallel to the peripheral surface of the clamping piston 12 aligned form one to the locking ring 36 have adapted shape. Between the insertion groove 35 and the first circumferential locking groove 31 the locking profile 30 is an activation cone 37 provided, the opposite the clamping piston axis A has an inclination angle of about 20 °. The activation cone 37 bridges the difference of the deep insertion groove 35 opposite the cylinder peripheral surface of the tensioning piston 12 and the locking grooves following in the direction of engagement 31 the locking profile 30 , Each only about half of the radial ring thickness of the locking ring relative to the cylinder peripheral surface of the clamping piston 12 are deepened.

In the tension end of the piston bore 11 is like in 4 shown between the tension side front 38 the tensioner housing 10 and the circumferential groove 29 a flat inclined insertion cone 39 provided, opposite the piston bore 11 or the clamping piston axis A preferably has an inclination angle between 10 ° and 20 °, wherein the span-side diameter of the insertion cone 39 at least the diameter of the relaxed locking ring 36 equivalent. When installing the tensioning piston 12 into the piston bore 11 the tensioner housing 10 the loose meets in the introduction groove 35 arranged slotted locking ring 36 on the introductory cone 39 at the tension end of the piston bore 11 and is from the introductory cone 39 centered in the radial direction, wherein it on the tension-side insertion groove wall of the insertion groove 35 is applied. Upon further retraction of the tensioning piston 12 into the piston bore 11 by means of a tensioning piston 12 manually or automatically applied force is the locking ring 36 through the tapered introductory cone 39 compressed and so in the introduction groove 35 disposed that the tensioning piston head 34 so far into the piston bore 11 can dip until the locking ring 36 in the circumferential groove 29 is positioned, see also 5a and 5b , While 5a the last section of compressing the latch 36 in the introduction groove 35 by means of the introduction cone 39 shows is in 5b the state shown in which the locking ring 36 beyond the introductory cone 39 relaxed in the circumferential groove 29 is arranged. In the in 5b shown location of the locking ring 36 or the adjusting device 27 is the in 3 shown transport lock 21 activated, causing the tensioning piston 12 in its position in the tensioner housing 10 is fixed.

After installation of the clamping device 7 in the engine block 8th becomes the transport security 21 disabled, what with the in 3 illustrated transport lock 21 over another deep retraction of the tensioning piston 12 into the piston bore 11 is effected. After disabling the transport lock 21 pushes the compression spring 16 the tensioning piston 12 in the clamping direction from the piston bore 11 , where, as in 5c shown, the tension-side groove wall 32 the circumferential groove 29 the slotted locking ring 36 over the activation cone 37 in the direction of the Rastnuten 31 the locking profile 30 pushes. This will cause the locking ring 36 through the expanding activation cone 37 against the spring tension of the locking ring 36 expanded and, as in 5d shown in the first locking groove 31 the locking profile 30 pushed. The locking ring is seated 36 by the spring tension safely in the locking groove 31 , This first disengagement of the tensioning piston 12 from the piston bore 11 the tensioner housing 10 by the bias of the compression spring 16 , optionally in combination with the pressure of the hydraulic fluid in the pressure chamber 13 , activates the adjuster 27 for the stepwise readjustment of the working range of the tensioning piston 12 during operation of the tensioner 7 ,

As a slotted locking ring 36 can be used both for the particular application produced round wire ring of a spring wire, and also different cross-sectional profiles for use as a locking element 28 are suitable, or it can be used as a cost-effective alternative, a conventional round wire snap ring spring wire according to DIN 7993. The use of a standardized and used in many ways component can significantly reduce the cost. In this case usually lies the ring thickness of the locking ring 36 , ie the diameter of the spring wire of the locking ring 36 at 0.6 mm to 2.0 mm, for tensioning pistons 12 be used with a diameter of 9 mm to 15 mm. With regard to the miniaturization of clamping devices 7 for internal combustion engines is the use of simple and standardized components, here a slotted circular section-shaped locking ring 36 more important, as conventional locking elements 28 in the form of specially shaped locking clips in these dimensions are not or only very expensive to produce.

The 6a and 6b show once again the function of the adjusting device 27 the tensioning device according to the invention 7 , After installation of the clamping device according to the invention 7 in the engine block 8th of the internal combustion engine moves the tensioning piston 12 , as in 5d shown as far as the piston bore 11 out until the adjuster 27 is activated. Depending on the distance to the pressure area 9 the tensioning rail 6 the tensioning piston moves 12 also further from the piston bore 11 out, leaving the latching ring 36 already on a second or third locking groove 31 jumps. Moves the tensioning piston 12 in operation due to large vibration shocks or when starting the engine very deep into the piston bore 11 a, beats in the locking groove 31 sitting latching ring 36 on the engagement side groove wall 33 the circumferential groove 29 on the incline the locking ring 36 firmly in the locking groove 31 suppressed. So it comes to limiting the retraction of the tensioning piston 12 because of the locking ring 36 on the engagement side groove wall 33 in the locking groove 31 is blocked.

At wear of a drive chain 4 in chain drive 1 the tensioning piston moves 12 for tensioning the drive chain 4 further from the piston bore 11 out, leaving the latching ring 36 on the tension side groove wall 32 the circumferential groove wall 20 abuts and of the tension side groove wall 32 on further expression of the tensioning piston 12 in the following locking groove 31 is pushed. By this automatic adjustment of the clamping device 7 changes the working position of the clamping piston 12 in the piston bore 11 without being affected by the length of the circumferential groove 29 in the direction of the clamping piston axis A defined free working range of the tensioning piston 12 changed.

LIST OF REFERENCE NUMBERS

1

chain drive

2

Driven sprockets

3

drive sprocket

4

drive chain

5

guide rail

6

tensioning rail

7

jig

8th

block

9

pressing area

10

tensioner housing

11

piston bore

12

clamping piston

13

pressure chamber

14

check valve

15

supply channel

16

compression spring

17

vent hole

18

gap

19

packing

20

valve seat

21

transport safety

22

threaded portion

23

flange

24

hexagon

25

poetry

26

opening

27

readjustment

28

locking element

29

circumferential groove

30

catch profile

31

locking grooves

32

tensioned groove wall

33

rear groove wall

34

Clamping piston head

35

introduction groove

36

locking ring

37

activation cone

38

front

39

insertion cone

A

Clamping piston axis

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10014700 A1 [0003]
• DE 19680418 C1 [0004]
• DE 102011101865 A1 [0005]
• DE 102015013121 A1 [0006]

Claims (10)

Clamping device (7), in particular for a timing chain of an internal combustion engine, with a tensioner housing (10), in a piston bore (11) of the tensioner housing (10) guided tensioning piston (12), and an adjusting device (27) for gradually adjusting the working range of the tensioning piston (12), wherein the adjusting device (27) comprises a detent profile (30) arranged on the front region of the tensioning piston (12) in the tensioning direction and a detent element (28) engaging in the detent profile (30), characterized in that the detent element (28 Is formed as a slotted locking ring (36), the locking profile (30) of the clamping piston (12) at the front end in the clamping direction an insertion groove (35), in which during assembly of the clamping piston (12) in the piston bore (11) Locking ring (36) is arranged captive and compressible, and the piston bore (11) of the tensioner housing (10) at the front end in the clamping direction a flat insertion cone (39) mi t has an angle of inclination to the piston bore (11) of 5 ° to 30 °, preferably an angle of inclination between 10 ° and 25 °, in order during assembly of the clamping piston (12) into the piston bore (11) by means of a force on the clamping piston (12) Centering and compressing the latching ring (36) in the insertion groove (35) and inserting the latching ring (36) arranged in the insertion groove (35) into the piston bore (11). Clamping device (7) after Claim 1 , characterized in that the depth of the insertion groove (35) is greater than the radial ring thickness of the locking ring (36) minus the width of the gap (18) between the clamping piston (12) and the piston bore (11). Clamping device (7) after Claim 2 , characterized in that the depth of the insertion groove (35) is between 1.0 times and 2.65 times the radial ring thickness of the locking ring (36). Clamping device (7) according to one of Claims 1 to 3 , characterized in that the slotted locking ring (36) is formed as a round wire ring and made of a spring wire steel, preferably a conventional round wire snap ring. Clamping device (7) after Claim 4 , characterized in that the unloaded opening width of the slotted locking ring (36) is 1.5 to 5.0 times, preferably 2.0 to 4.0 times, the radial ring thickness of the locking ring (36). Clamping device (7) according to one of Claims 1 to 5 , characterized in that the length of the flat insertion cone (39) in the longitudinal direction of the piston bore (11) is greater than the ring thickness of the locking ring (36), preferably between 3.0 and 9.0 times the radial ring thickness of the locking ring (36 ) is Clamping device (7) according to one of Claims 1 to 6 , characterized in that the latching profile (30) of the clamping piston (12) has a plurality of latching grooves (31), wherein between the clamping direction at the front end of the clamping piston (12) arranged insertion groove (35) and a first adjacent latching groove (31) has a flat Activation cone (37) is provided, with an inclination angle to the clamping piston axis (A) of 10 ° to 30 °, preferably an inclination angle between 15 ° and 25 °. Clamping device (7) according to one of Claims 1 to 7 , characterized in that at the tension-side end of the piston bore (11) a circumferential circumferential groove (29) is provided, which defines the free travel of the tensioning piston (12) together with the latching profile (30) engaging latching ring (36). Clamping device (7) according to one of Claims 1 to 8th , characterized in that the tensioning device (7) is designed as Einschraubspanner. Chain drive (1), in particular a timing chain drive of an internal combustion engine, with a drive sprocket (3), at least one output sprocket (2), a drive chain (4) connecting the drive sprocket (3) and the at least one output sprocket (2) and a drive chain ( 4) exciting clamping device (7) according to one of Claims 1 to 9 ,

Images