WO2010023010A1

WO2010023010A1 - Hydraulic tensioning element

Info

Publication number: WO2010023010A1
Application number: PCT/EP2009/058553
Authority: WO
Inventors: Roman Kern; Thomas Ullein
Original assignee: Schaeffler Kg
Priority date: 2008-08-23
Filing date: 2009-07-07
Publication date: 2010-03-04
Also published as: DE102008039505A1

Abstract

Hydraulic tensioning element, inserted into tensioning systems of traction machine drives, particularly chain drives of internal combustion engines, comprising a housing (1) with a guide element (2) and a pressure-applied piston (3) guided axially relative to the guide element (2), wherein a fluid enters via a fluid inlet opening (17) provided within the bottom (6) and a valve plate (10) arranged in the guide element (2) into a pressure chamber (5) delimited by the guide element (2) and the piston (3), wherein a bottom (6) delimiting the guide element (2) is tapered conically in the direction of the valve plate (10) and forms a valve seat (18) for the valve plate (10) at a transition zone to the fluid inlet opening (17), wherein between the guide element (2) and the piston (3) at least one spring element (12) is supported.

Description

Name of the invention

Hydraulic tensioning element

Field of the invention

The present invention relates to a hydraulic tensioning element, used in tensioning systems of traction drives, in particular chain drives of internal combustion engines, comprising a housing with a guide element and a piston axially guided to the guide element pressurized piston, wherein a fluid via a formed inside the bottom Fluideinlassöff- opening and one in the guide element arranged valve plate into a bounded by the guide member and the piston pressure chamber, wherein a guide element delimiting bottom is conically tapered in the direction of the valve plate and forms a valve seat for the valve plate at a transition zone to the fluid inlet opening, wherein between the guide member and the piston supported at least one spring element.

Background of the invention

A hydraulic tensioning element according to the aforementioned type is known from the document DE 10 2007 047 170 A1. In the hydraulic tensioning system described there, a one-way valve is provided as a plate valve, which comprises two non-cutting components: a holding element enclosing a valve seat, in which a valve body designed as a disk is guided secured against loss. The designed as a cage holding element which comprises the valve body, designed in the manufacture as consuming, as well as the pre-assembly of the disk designed as a valve body into the cage. Object of the invention

The invention is therefore based on the object to produce an easy-to-assemble and cost-effective securement unit between a one-way valve and a guide element of a hydraulic tensioning element.

Summary of the invention

The object is achieved in that within the bottom of the guide element a spaced from the valve seat stage is arranged, on which a one-way valve is arranged, which has a valve plate and the stroke of the valve plate limiting circlip, wherein the retaining ring is captively fitted into the stage ,

One step describes a shoulder which is delimited at its two ends by respective surfaces extending perpendicularly thereto, one of the surfaces corresponding to a bottom of the guide element running essentially radially to the longitudinal axis of the tensioning element. The guide element and the bottom formed as a valve seat are preferably made of a metallic material see. To reduce the noise, the damping and / or wear, it is advantageous if the metallic valve seat or the valve plate has a plastic coating or a rubber coating.

In a preferred embodiment of the invention, several stages are introduced into the bottom of the guide element. The step rise in this case runs from the valve seat in the direction of the piston. The diameters of the individual levels resulting from the course of the steps increase in the direction of the course of the steps.

The valve plate is arranged at the foot of the stage play on the valve seat. The stroke of the valve plate limiting circlip is force-fit or form-fitting in a spaced-apart from the valve seat stage. On- Because of the stepped bottom of the guide element, the one-way valve can be fitted captive into the guide element without the aid of complicated components. The guide element with integrated one-way valve can thus be introduced as a completely pre-assembled component in the hydraulic tensioning element. Both the retaining ring and the valve plate are preferably made without cutting. Both components can be made of plastic as well as metal. In order to keep the noise low, it makes sense that at least one of the two components is made of plastic.

According to various developments of the invention, the piston has different shapes. This has the consequence that the guide element is adapted to the particular shape of the piston. A variant consists in that the piston is designed as a solid cylinder, which is arranged longitudinally movable within the guide element. Another variant shows a hollow cylindrical piston which surrounds the guide element and is movable longitudinally movable.

In a further embodiment of the invention, at least two concentric coil springs are arranged axially between the guide element and the piston. The two spring elements have different spring wire diameter, wherein preferably the spring element is arranged with the smaller spring wire diameter within the spring element with the larger spring wire diameter. In order to obtain the desired damping of the spring-pressure-loaded piston and to prevent over-dimensioning of the spring element, the use of more than one spring element has proven to be expedient, as well as the interlocking arrangement of the two spring elements.

It is particularly advantageous if the piston on the bottom side on its side facing away from the traction means has an inner gradation, so that at least one spring end of the spring element can be supported on at least one stage of the bottom of the piston and on the opposite side te the bottom of the piston can support at least one spring end at least one stage of the arranged at the bottom of the guide element stage. The arranged in the bottom of the piston gradation allows additional guidance of the individual sections of the spring elements and provides improved support surfaces for the spring ends. As a result of the introduced into the bottom of the guide element stages, one of the spring elements, preferably that which is surrounded by a further spring element is supported with one of its spring ends on the locking ring, which is fitted into the guide element.

It can also be provided that a latching device is arranged radially between the guide element and the piston, consisting of radially encircling latching grooves and a latching ring or a latching pin. This locking device performs several functions, on the one hand it represents a transport haven, on the other hand, a limitation, so that the piston can not be pushed out of the housing under the force of the spring element. After mounting the tensioner, the transport lock is unlocked. To start up the piston this moves by means of the spring element on the individual Rastierungspunkte controlled in the direction of the clamping rail.

According to a further preferred development of the invention, there is a leakage gap radially between the guide element and the piston, so that the excess fluid in the pressure chamber can escape. The locking device is partially provided as a leakage gap.

Brief description of the drawings

Embodiments of the invention are illustrated in the figures, which are described in detail below, wherein the invention is not limited to these embodiments. Show it:

FIG. 1 shows a hydraulic tensioning element, Figure 2 is a hydraulic clamping element with a hollow cylindrical

Piston and

FIG. 2 a shows a detailed section of the one-way valve fitted in the bottom of the guide element.

Detailed description of the drawings

FIG. 1 shows a hydraulic tensioning element, comprising a housing 1 with a guide element 2 and a pressure-actuated piston 3 axially guided in relation to the guide element 2. The guide element 2 is a pot-type component in which the cylindrical piston 3 is guided in a longitudinally movable manner. Via a fluid inlet opening 17 introduced into the bottom 6 of the guide element 2, fluid, preferably engine oil, flows via a valve plate 10 arranged in the guide element 2 into a pressure chamber 5 bounded by the piston 3 and guide element 2. The guide element 2 delimiting bottom 6, which is tapered in the direction of the valve plate 10, forms a valve seat 18 for the valve plate 10 at a transition zone to the fluid inlet opening 17. In order to limit the stroke of the valve plate 10 during operation, one is within the Floor 6 arranged and spaced from the valve seat 18 stage 8 a snap ring 11 by means of force and / or positive fit accurately inserted.

The valve plate 10 as well as the locking ring 11 form a one-way valve 4 and can be made both of plastic and metal. Preferably, for noise optimization, one of the components should be made of plastic and the other of metal.

The introduced within the bottom 6 of the guide member 2 graduation allows an integrative mounting of the one-way valve 4 in the bottom 6 of the guide element 2, thereby no additional components are needed to manufacture a ready-to-mount guide element 2 with one-way valve 4.

The bottom 7 of the piston 3, as well as the opposite bottom 6 of the guide element 2, gradations. These gradations are as Guiding and contact points for the spring ends 13 of the arranged between the piston 3 and the guide element 2 spring element 12 is provided. The spring element 12 is a concentric helical spring arranged inside one another, wherein preferably that helical spring, which is arranged inside the outer helical spring, has a smaller spring wire diameter than the outer helical spring.

During operation in the traction drive, it can lead to unwanted hitting the chain. These shocks are damped by the tensioning element. To achieve the damping, a predefined spring force is required. In order to achieve this spring force, at least two spring elements 12 are arranged one inside the other to avoid an increase in the axial space.

To support the spring element 12, oil continues to flow into the pressure chamber 5 via the fluid inlet opening 17 until the piston 3 comes into contact with a tensioning rail. Due to the high pressure, the valve plate 10 is pressed in the direction of the valve seat 18, so that the excess oil only via a arranged between the guide element 2 and 3 Koben ben 3 leakage gap can escape.

In addition, a latching device 20 is arranged in the region of the leakage gap 16 between the guide element and the piston 3. This latching device 20 is formed from radially encircling latching grooves 14 and a latching ring 15 arranged displaceably for this purpose. During transport and assembly of the locking ring 15 holds the prestressed piston 3 in a retracted position in the guide member 2. To bring the assembled clamping element in its operating position, the locking ring 15 is released by pressing the piston 3. In order to prevent the piston 3 from snapping out of the guide element 2, the piston 3 moves in the direction of the tensioning rail past several detent points, which it overcomes by means of spring force. Figures 2 and 2 a also show clamping elements which correspond functionally to the clamping element shown in Figure 1. The reference numbers to the components of FIGS. 2 and 2a are identical to the reference numbers of the components in FIG. 1. In the following, only the components that differ from FIG. 1 will be discussed in more detail. The embodiment shown in Figure 2 shows the piston 3 as a cup-shaped housing and a hollow cylindrical guide element 2 which is enclosed by the piston 3. The piston is arranged longitudinally movable relative to a longitudinal axis 19 and the guide element 2. Again, the bottom 6 of the guide member 2 is formed as a valve seat 18, from which a spaced stage 6 is provided for receiving a one-way valve 4.

LIST OF REFERENCE NUMBERS

casing

guide element

piston

one-way valve

pressure chamber

Bottom (of the guide element)

Bottom (of the piston)

Stage (in the guide element)

Stage (in the piston)

valve plate

circlip

spring element

spring end

Rest grooves

locking ring

leakage gap

Fluid inlet port

valve seat

longitudinal axis

locking device

Claims

claims

1. Hydraulic tensioning element used in tensioning systems of traction drives, in particular chain drives of internal combustion engines, comprising a housing (1) with a guide element (2) and a guide element (2) axially guided pressurized piston (3), wherein a fluid over a fluid inlet opening (17) formed inside the bottom (6) and a valve plate (10) arranged in the guide element (2) flow into a pressure chamber (5) delimited by the guide element (2) and the piston (3), wherein the guide element (2) delimiting bottom (6) is conically tapered in the direction of the valve plate (10) and at a transition zone to the fluid inlet opening (17) forms a valve seat (18) for the valve plate (10), wherein between the guide element (2) and the Piston (3) at least one spring element (12) is supported, characterized in that within the bottom (6) of the guide element (2) from the valve seat (18) spaced stage (8 ) is arranged, on which a one-way valve (4) is arranged, which has the valve plate (10) and a stroke of the valve plate (10) limiting circlip (11), wherein the retaining ring (11) captive fitted into the step (8) is.

2. Hydraulic tensioning element according to claim 1, characterized in that the piston (3) within the guide element (2) is arranged longitudinally movable.

3. Hydraulic tensioning element according to claim 1, characterized in that the piston (3) surrounds the guide element (2) and is movable longitudinally thereto.

4. Hydraulic tensioning element according to claim 2 or 3, characterized in that the spring element (12) is designed as a concentric double helical spring.

5. Hydraulic tensioning element according to claim 4, characterized in that the bottom (6) of the guide element (2) opposite the bottom (7) of the piston (3) has at least one step (9).

6. Hydraulic tensioning element according to claim 5, characterized in that at least one spring end (13) of the spring element (12) on at least one step (9) of the bottom (7) of the piston (3) is supported.

7. Hydraulic tensioning element according to claim 6, characterized marked, that at least one spring end (13) of the spring element (12) on at least one step (8) of the bottom (6) of the guide element (2) is supported.

8. A hydraulic tensioning element according to claim 7, characterized marked, that a spring end (13) on the retaining ring (11) is supported.

9. Hydraulic tensioning element according to claim 1, characterized in that a latching device (20) is arranged radially between the guide element (2) and the piston (3).

10. Hydraulic tensioning element according to claim 10, characterized in that a leakage gap (16) is partially formed as a latching device (20).