CN105247243B - Stretcher with oil management feature - Google Patents

Abstract

A kind of stretcher for being tensioned endless drive member is provided.The stretcher includes base portion, tensioner arms, pivot bushings, drive member engagement member and spring.The base portion includes pivot, spring cup and back plate.The pivot has base end part and distal portion, and defines pivotal axis.

Description

Stretcher with oil management feature

The cross reference of related application

The U.S. Provisional Patent Application No.61/827 submitted this application claims on May 24th, 2013,345 rights and interests, the U.S. The content of state's temporary patent application is incorporated to by reference, as fully elaborated herein.

Technical field

The present invention relates to belt tightener, and more particularly to the tensioning used in immersion oil band application on the engine Device.

Background technology

It is known that stretcher is set on timing belt actuator on vehicle motor.Become in recent years more universal , set band to cause band to can act as using the replacement Sexual behavior mode of timing chain actuator on the engine in oil environment, Without carrying out more redesign to this part of engine.Although substantial amounts of work has been done to improve immersion oil band The performance of formula timing belt actuator, or the lasting demand for further improving performance be present.Especially, can from improvement Be benefited be on one side stretcher on this timing belt actuator service life.

The content of the invention

In an aspect, there is provided a kind of stretcher, the stretcher are configured to guiding oil and other pollutants away from fixed The slidingsurface of bushing of the position between pivot and tensioner arms.In some embodiments, the stretcher is configured to guide Oil and other pollutants are away from the bearing between belt wheel and the tensioner arms of stretcher.In other embodiments, the stretcher It is configured to promote oil towards bearing.

In another aspect, there is provided a kind of stretcher, the stretcher are configured to guiding oil and other pollutants away from band Bearing between wheel and the tensioner arms of stretcher.

In other embodiment, the stretcher is configured to towards between belt wheel and the tensioner arms of stretcher Bearing promotes oil.

In another aspect, there is provided a kind of stretcher for being used to be tensioned endless drive member.The stretcher include base portion, Tensioner arms, pivot bushings, driving part engagement member and spring.The base portion includes pivot, spring cup and back plate.Pivot has There are base end part and distal portion, and define pivotal axis.Pivot have allow to use through its pivot aperture, the pivot aperture Passed through in the installation fastener that stretcher is attached to fixed structure.Spring cup is fixedly connected to pivot and with axially With the spring tegmental wall extended circumferentially over upon, the spring tegmental wall has inner radial surface and radially-outer surface.Back plate is fixedly connected to Pivot and it is configured for being oriented base portion relative to fixed structure.Tensioner arms are pivotally mounted on the pivot On to be moved pivotally around pivotal axis.Pivot bushings is positioned between tensioner arms and pivot.The radial direction of pivot bushings and pivot Outer surface frictionally engages.Drive member engagement member is mounted to tensioner arms and is positioned to engage endless drive member. Spring is positioned to promote tensioner arms along coiling direction.Tensioner arms have the skirt axially and circumferentially extended, the skirt Shape portion is axially overlapping axially to impale spring housing with spring tegmental wall, wherein, one of spring tegmental wall and skirt surround The other of spring tegmental wall and skirt.At least one guide wall is from the another one direction in spring tegmental wall and skirt The one in spring tegmental wall and skirt extends axially outward.At least one guide wall and spring tegmental wall and skirt In the one do not contact.

In another aspect, there is provided a kind of stretcher, the stretcher have tensioner arms, and tensioner arms have skirt, The skirt is gradually reduced to promote oil to be flowed towards bearing, especially on the direction towards the bearing being arranged in tensioner arms It is in the application of immersion oil band.In some embodiments, parent can be provided to the surface of the interface between bearing and skirt Oiliness.

In another aspect, there is provided a kind of stretcher, the stretcher have tensioner arms, and tensioner arms have skirt, The skirt is gradually reduced on direction of the guiding oil away from spring housing, slip of the spring housing exposed to bushing and tensioner arms Surface or bushing pivot the slidingsurface of surrounded pivot with tensioner arms.

By referring to the following description of accompanying drawing, other feature and advantage will be apparent.

Brief description of the drawings

Fig. 1 is the engine with the timing belt actuator for including timing belt tightener according to the embodiment of the present invention Front view；

Fig. 2 is the distal part stereogram of the stretcher shown in Fig. 1；

Fig. 3 is the base portion stereogram of the stretcher shown in Fig. 1；

Fig. 4 is the side elevation of the stretcher shown in Fig. 1；

Fig. 5 is the side elevation of the spring cup of the stretcher shown in Fig. 1；

Fig. 6 is the side cross-sectional view of the stretcher shown in Fig. 1.

Fig. 7 is the side elevation of the spring cup of stretcher, wherein, there is optional extra oil to release logical on spring cup Road；

Fig. 8 is stretcher illustrating to be dropped in the stereogram of the oily part released on stretcher；

Fig. 9 is the side cross-sectional view of the stretcher including some oleophobic coatings at select location；

Figure 10 is the top view of the stretcher shown in Fig. 1, wherein, have in the tensioner arms of stretcher another optional Oil release passage；

Figure 11 is the side cross-sectional view of the amplification of the stretcher at select location with some oleophobic coatings.

Embodiment

Fig. 1 is the plan that can be used for making the embodiment of the stretcher 10 of the tensioning of endless drive member 11, and the ring-type is driven Dynamic component 11 is a part for the annular drive device on vehicle motor 913.For illustrative purposes, engine 913 is illustrated For simple rectangle.It should be understood that engine 913 can have any suitable shape.

Annular drive device can use the belt wheel 912 on the bent axle of engine 913 to be driven via endless drive member 11 Move at least one part.In shown example, cam shaft pulley 916 is powered portion via endless drive member 11 Part.Idle pulley 918 is also shown as engaging with endless drive member 11.

Endless drive member 11 can be timing belt, or endless drive member 11 can be any other suitable type Endless drive member.Only for convenience and legibility, endless drive member 11 can be referred to as band 11 or timing herein Band 11.

For reference picture 2 to Fig. 6, stretcher 10 is illustrated in further detail in it.Stretcher 10 includes base portion 12, tensioner arms 14th, pivot bushings 16 (it provides the source that the motion to tensioner arms 14 is damped), bearing 18, belt wheel 20, tensioning spring 22nd, installation axle 27 and installation fastener 28.

Fig. 2 is configured to suppression oily (being shown with 100) to the stretcher 10 shown in Fig. 6 and is moved to the selected of stretcher 10 In region, as described further below.In dry application (that is, band 11 without immerse oil bath pan in application in, The application is referred to as the application of immersion oil band), oil 100 may be from the leakage in such as engine or the leakage of other oil lubrication parts Source.Pollutant, such as the particulate from engine may be carried in oil 100, the dirt in engine room, such as start Machine cooling agent, electronic-controlled power steering fluid, the liquid pollutant of brake fluid and water.No matter whether oil 100 contains pollutant, it is not desirable that Oil 100 be moved to stretcher 10 be intended to operation during in the region that is damped of motion to tensioner arms 14, this be because The frictional behavior of damping element can be changed for pollutant entrained in oil and/or oil, this will influence the amount of the damping of generation.Reason What is thought is to have predictable consistent damping in stretcher 10.Because damping it is too big or too it is small can all produce it is unfavorable As a result.If arm 14 move during excessive friction (i.e. excessive damping) be present, exist tensioner arms 14 lock can Energy property, tensioner arms 14 are locked from the sufficient movement during the tension fluctuation of band 11 of tensioner arms 14, and this can cause band 11 Middle tension fluctuation slows down deficiency, so as to cause the service life of band 11 to be likely to reduced.If there is too small friction, then band 11 On tension fluctuation can increase in band 11 " negative " tension force (i.e. band 11 can be loose) point momentarily occurs, this allows band 11 tooth skips the pulley teeth on one or more belt wheels in each belt wheel driven by band 11.This tooth, which is jumped, can cause gas The loss of door timing, this can cause to the badly damaged of engine 913.It is advantageous to kept enough in stretcher 10 Amount of friction.

Reference picture 6, base portion 12 include pivot 12a, spring cup 12b and back plate 12c.In figure 6 in shown embodiment, These parts 12a, 12b and 12c can be single parts.But some parts or institute in part 12a, 12b and 12c There are these parts to be integrally formed together each other.Pivot 12a can be attached to fixed structure --- for example framework or starts First area (Fig. 4) on the cylinder body of machine 913.In order to clearer, fixed structure is vehicle to install stretcher 10 Some parts be considered as fixed all suitable structure divisions totality (or in the case of non-vehicle application, fixed knot Structure is the totality of the ambient of stretcher).In vehicle application, fixed structure is by corresponding to the framework of vehicle, engine cylinder-body With engine mounting framework, vehicle body and any non-moving structural detail and part.Fixed structure typically has vertical table Face, wherein stretcher 10 are arranged on the vertical surface to cause stretcher 10 to have in use as shown in Figures 1 and 2 Orientation, still, the surface can be any with being similarly oriented to the offer of stretcher 10 with the orientation shown in Fig. 1 and Fig. 2 Orientation.

Pivot 12a has base end part 30 (the immediate end of fixed structure being mounted to pivot 12a) and remote End 32, and pivot 12a defines pivotal axis Aps (Fig. 2 and Fig. 6).

Pivot 12a, which has, runs through its pivot aperture 34, and the installation axle 27 through pivot aperture 34 is received in pivot aperture 34. Installation axle 27, which has, runs through its installation axle aperture 37, and installation axle aperture 37 is allowed for pacifying base portion 12 and whole stretcher 10 The installation fastener 28 for being filled to fixed structure passes through.Installation axle aperture 37 can be eccentric (being offset from pivot aperture 34), So as to allow that pivotal axis Aps position is adjusted when stretcher 10 is arranged on fixed structure.Shown In embodiment, this skew is arrived by optimal viewing in fig. 2.Installation axle 27 need not be set in some embodiments. In such embodiment, pivot aperture 34 can directly receive installation fastener 28.

Pivot 12a can be made up of for example suitable steel of any suitable material.

Back plate 12c be fixedly mount to pivot 12a base end part 30 (such as by press-fit, rivet clasp, welding, gluing or Any other suitable mode).In shown embodiment, back plate 12c has the outer surface for being press-fitted into pivot 12a The loop portions 40 of (being shown with 42).The center port 45 that loop portions 40 are extended through in spring cup 12b enters the interior of spring cup 12b Portion (is shown) with 44.Back plate 12c also includes cup part 46 and 48, cup part 46 and 48 and cup part 46 and 48 coordinate with Spring cup 12b is attached to back plate 12c, and is therefore attached to pivot 12a.Spring cup 12b, which has, axially and circumferentially to be prolonged The spring tegmental wall 50 stretched, spring tegmental wall 50 have inner radial surface 52 and radially-outer surface 54.When base portion 12 is attached to fixed knot During structure, the locating features 59 on back plate 12c coordinate with relative to fixed knot with the corresponding locating features on fixed structure Structure is oriented to base portion 12.In the exemplary embodiment, the locating features 59 on back plate 12c be with fixed structure The protuberance extended on base portion of groove (not shown) engagement.

Tensioner arms 14 are pivotally mounted on pivot 12a to be moved pivotally around pivotal axis Aps.Pivot bushings 16 positions Between tensioner arms 14 and pivot 12a.Pivot bushings 16 may be fixedly attached to the inner surface 53 of tensioner arms 14 and Pivot bushings 16 (shows) that place and pivot 12a radially-outer surface 42 are frictionally engaged in the inner radial surface of itself with 63.Cause This, inner surface 63 is the slidingsurface of pivot bushings 16.Pivot bushings 16 to stretcher 10 so that provide frictional damping, this help Stretcher 10 suppresses the fluctuation of belt tension, and the fluctuation of the belt tension is the camshaft institute for example driven by vibration source by belt wheel 916 The motion of the valve of driving and appear in band 11.This frictional damping allows stretcher 10 to absorb these tension fluctuations and controlled System band tensioning.Although pivot bushings 16 can advantageously be fixedly positioned on the inner surface of tensioner arms 14 with pivot 12a The sliding contact of outer surface 42, but pivot 12a and and tensioner arms may also be fixedly connected to for bushing 16 14 sliding contact of inner surface 53.

Bushing 16 can be for example impregnated with the suitable materials of PTFE (polytetrafluoroethylene (PTFE)) or some other by any suitable material The suitable nylon of material is made, or bushing 16 is coated with PTFE or some other suitable materials on surface 63.

Spring 22 is positioned to promote tensioner arms 14 in a first direction, and this drives belt wheel 20 in band 11.In Fig. 2 by First direction shown in D1 can be referred to as coiling direction.This is the direction for reducing the potential energy in spring 22.Tensioner arms 14 motion in the opposite direction increases the potential energy in spring 22.The direction can be referred to as spring loads direction.Bullet Spring 22 has the first end 22a engaged with base portion chocking construction 60 and the second end engaged with tensioner arms chocking construction 62 22b.Base portion chocking construction 60 can be the groove in spring cup 12b.The structure of groove 60 is described further below.Stretcher Arm chocking construction 62 can be by the abutment surface of the end 22b abuttings of spring 22.

Spring 22 can be the spring of any suitable type, such as spiral winding torsionspring.

Tensioner arms 14 can be based on the engagement of band 11, from spring 22 and coming from arm 14 from belt wheel 20 The power for the damping force that frictional force is for example provided by bushing 16 and on coiling direction and spring loads direction pivotally Motion.Tensioner arms 14 can be made up of for example suitable aluminium of any suitable material.

Being optionally positioned within limitation tank 55 in tensioner arms 14 has a first end 55a and the second end 55b, and first End 55a and the second end 55b engages with the protuberance 57 on back plate 12c thinks pivot of the tensioner arms 14 relative to base portion 12 Motion setting limitation.First end 55a sets the limitation for being referred to as free arm stop and move portion, and this is limited to the minimum in spring 22 Allow the position of potential energy.The second end 55b sets the limitation for being referred to as load retainer, and this is limited in spring 22 The position of maximum allowable potential energy.Retainer 55a and 55b position can be according to the overall operation of spring 22 and stretcher 10 Property and life-span are selected.

In the embodiment shown in Fig. 2 to Fig. 6, belt wheel 20 is rotatably mounted to stretcher via bearing 18 Arm 14 is with around the belt wheel axis Ap rotations being spaced apart with pivotal axis Aps.Belt wheel 20 is shown as that there is flanged band to engage Surface 56, but surface 56 can also not have flange.Belt wheel 20 can be by the metal material of for example such as suitable steel etc Any suitable material is made.

Bearing 18 includes being attached to the inner ring 18a of tensioner arms 14, the outer ring 18b for being attached to belt wheel 20, multiple rolling members Part 18c (such as ball), distal end protective cover 18d and base portion protective cover 18e.

Tensioner arms 14 have the skirt 64 that axially and circumferentially extends, skirt 64 have radially-outer surface 65 with Inner radial surface 67.Skirt 64 and spring tegmental wall 50 are axially overlapping axially to impale spring housing 66 (i.e. for spring 22 Room).One of spring tegmental wall 50 and skirt 64 surround the other of spring tegmental wall 50 and skirt 64.Shown Embodiment in, skirt 64 surrounds spring tegmental wall 50.

At least one guide wall 68 another one described in spring tegmental wall 50 and skirt 64 is towards spring tegmental wall 50 and skirt The one in shape portion 64 extends radially outwardly.In the present embodiment, guide wall 68 is from spring tegmental wall 50 towards skirt 64 stretch out.In addition, in shown embodiment, two axially adjacent each other guide walls 68 are provided with.

It should be noted that guide wall 68 is not in contact with skirt.Therefore, do not have between spring tegmental wall 50 and skirt 64 There is frictional engagement.This allow that the amount of the frictional damping provided during the pivoting action of tensioner arms 14 may undesirably show Write increase.

Reference picture 6, wall 68 have base portion side 70 and distal face 72.Base portion side 70 can substantially radially extend, from And the oil suppressed on any outer surface 54 for dropping onto spring tegmental wall 50 climbs up wall 68.In addition, in the outer surface of spring tegmental wall 50 In the case of having oil on 54, wall 68 is provided with the base portion side 70 radially extended and inhibits oil to climbing on base portion side 70. Distal face 72 extends radially outwardly towards base portion side face at an oblique angle.By setting inclined angle, distal face 72 helps Got in oil from the movement of distal face 72 of wall 68 to base portion side 70.Therefore, if some oil are mobile in some way more to wall 68 Distal side, then oil may (such as by vibration) climbing crosses wall 68 to reach base portion side 70.

Guide wall 68, which each has, slightly holds 74, slightly holds 74 to be separated close to skirt 64 but with skirt 64 shown in Fig. 5 Selected clearance G.More specifically, slightly end 74 is still inside with the footpath of skirt 64 close to the inner radial surface 67 of skirt 64 Surface 67 separates clearance G.Clearance G can be for example in about 0.5 millimeter or smaller of scope, or clearance G can be any Other are suitably measured.

Although wall 68 is shown as with approximate right angle triangular-section profile.Appoint although it is understood that can provide What his suitable profile.For example, the base portion side 70 of wall 68 need not extend generally radially out.Base portion side 70 can be with Inclined angle stretches out towards distal face 72.

It should be noted that although spring tegmental wall 50 is shown as general cylindrical shape in fig. 5 and fig. so that wall 68 Clearly it can be protruded from outer surface 54, but spring tegmental wall 50 itself can have any other suitable shape so that slightly End 74 is disposed proximate to the inner surface 67 of skirt 64 but separates selected amount with skirt 64, such as separates about 0.5 millimeter It is or less.For example, spring tegmental wall 50 can be alternatively conical shaped radially-inwardly tapered on base portion direction.Bullet Spring tegmental wall 50 outer end (outer end will form spring tegmental wall 50 distal portion) can slightly hold --- this slightly hold relative to The inner surface 67 of skirt 64 has selected clearance G --- and place terminates.

Wall 68 coordinates with skirt 64 to be moved in spring housing 66 with suppressing oil, and pivot 12a and lining are reached so as to suppress oil Interface between set 16.

In some embodiments, as shown, skirt 64 substantially extends in base portion so that its with cup member 46 and 48 axially overlapping and with cup member 46 and 48 outer surfaces (being shown with 78) separate selected clearance G 2 (Fig. 6).Gap G2 can be any suitably in scope, such as in 0.5 millimeter or smaller of scope.Alternately, clearance G 2 can be more than 0.5 millimeter, such as about 0.65 millimeter or smaller.Except there is provided extend radially outwardly and with the inner surface 67 of skirt 64 At least one wall 68 of clearance G is separated, by extending skirt 64 with axially overlapping with it with cup member 46 and 48 Between set clearance G 2, further suppress oil reach spring housing 66, and more particularly suppress oil reach pivot bushings 16 with Interface between pivot 12a.

Reference picture 6, spring cup 12b base end part abut back plate 12c.By the way that there is provided spring tegmental wall 50 and spring at which The large radius corner edges that 12b base wall 80 engages are covered, passage 82 is formd between spring cup 12b and back plate 12.The passage 82 be that spring cup oil releases passage.When being dropped in during operating of the oil in engine 913 on spring cup 12b, radius comers side Oil is promoted to fall into passage 82.Then oil due to gravity along the path 84 on the outside of spring cup 12b shown in Fig. 4 along logical Road 82 reaches the bottom of stretcher 10, and then oil can ooze from spring cup 12b.

In the figure 7 in shown alternative embodiment, it can be formed directly with the outer surface 54 of spring tegmental wall 50 Passage 86, passage 86 is closer to guide wall 68.Therefore the passage 86 may be used as spring cup oil and release passage so that oil along around The outside of spring tegmental wall 50 reaches bottom with the path shown in 87 and oozed.

Fig. 8 shows the selected part from stretcher 10.As can be seen in Figure 8, loop portions 40 can have There is the distal end lips 88 of projection.Therefore, any oil being moved in the spring housing 66 between spring cup 12b and back plate 12c will It can will drip in loop portions 40 and along the loop portions passage (being shown with 90) formed by lips 88.Then oil will be from logical Road 90 is fallen directly over groove 60 allows oil to subsequently depart from spring housing 66.

Reference picture 6, the outer surface 65 of skirt 64 can have the lip-like that the base end part in distal end and skirt 64 separates Portion 92.Lips 92 is moved in the base portion side of bearing 18 for suppressing oil.Skirt 64 is tapered in a distal direction so that oily Tend to fall towards lips 92, and flowed down then along the base portion side of lips 92 to fall from the bottom of skirt 64 Under.Although lips 92 is covered by belt wheel 20 in Fig. 4, oil circuit footpath is shown with 93 in detail in this figure.Alternatively, such as institute in Figure 10 Show, the outer surface 65 of skirt 64 there can be the skirt oil passage 94 being disposed thereon to help to prevent oil from being moved to bearing 18。

Thrust washer 95 can be arranged in the distal portion of tensioner arms 14 and can extend radially to belt wheel 20 Moved with suppression oil between thrust washer 95 and belt wheel 20 and reach the distal side of bearing 18.Thrust washer 95 be used for resist by Spring 22 is applied to the axial force in tensioner arms 14.

Reference picture 9, one or more surfaces can be provided with oleophobic coating to help to control oily flowing all the time.Oleophobic The example location of coating can be seen in fig.9：Oleophobic coating 98a is between installation axle 27 and thrust washer 95；Oleophobic coating 98b is between thrust washer 95 and tensioner arms 14；Distal portions of the oleophobic coating 98c in the close skirt 64 of skirt 64 On outer surface 65；In passages 90 of the oleophobic coating 98d in loop portions 40；And oleophobic coating 98e and 98f are respectively in pivot 12 On the base portion of bushing 16 and distal end on outer surface 42 on.Coating 98a, 98b and 98f coordinate to be gathered in suppressing oil Interface between the element of the remote end part of stretcher 10, so as to suppress oil in the immigration of these interfaces and reach bushing 16 Slidingsurface 63.Coating 98c is configured to suppress the generally vertical distal portion that oil reaches skirt 64, in skirt 64 Generally vertical remote end part oil can fall and move into bearing 18.Coating 98d is arranged to help and is gathered in loop portions passage 90 In oil 100 to promote oil 100 to be fallen along around the path of loop portions 40 and from loop portions 40.Coating 98e is arranged to press down Liquefaction is gathered in the base portion side in the space (being provided with bushing 16) between the surface 53 of arm 14 and the surface 42 of pivot 12 Outer surface 42 on.If oil 100 reaches the entrance in this space, capillarity be present and move oil 100 in the space to Possibility.By setting coating 98e, promote oil 100 to be fallen before the entrance is reached from pivot 12a, or promote oil 100 Avoid being firstly moved on the surface of coated 98e coatings.

It should be noted that oleophobic coating is only to cause the one way in which of material oleophobic.In some cases, material Material can be the inherently abundant oleophobic for not needing coating in itself.

Reference picture 11, it illustrates some features for the stretcher 10 that help is played in the application of immersion oil band.Such In, it may be desirable to promote oil to reach bearing 18 (although may still it is expected the slidingsurface for preventing oil from reaching bushing 16). In order to promote oil stream to be kept gradually (i.e. towards bearing 18) in a distal direction to bearing 18, the outer surface 65 of skirt 64 Contracting, and can there is no lips or oily passage on the outer surface 65 of skirt 64.In addition, can also not have on bearing 18 Protective cover.Then, oil flows down skirt 64 along path 105 and enters bearing 18.In fig. 11 in shown example, oleophylic applies Layer is used in two positions.Oleophylic coating 99a is arranged on the interface between the base portion side of bearing 18 and skirt 64；And Oleophylic coating 99b is arranged on the interface between the distal side of bearing 18 and thrust washer 95.In this embodiment, thrust pad Circle 95 can extend radially out beyond the space between inner ring 18a arrival inner ring 18a and outer ring 18b, and can have edge 101, edge 101 has base portion side 102, and base portion side 102 is tilted towards bearing 18 to promote the oil droplet in base portion side 102 to enter bearing In 18.Edge 101 can also have the distal side 103 that radial dimension reduces compared with base portion side 102, to avoid hindering oil from splashing Come and reach bearing (such as along path 106).

Figure 11 shows the application of passage 86, and passage 86 can be used for suppressing slidingsurface 63 of the oil stream to bushing 16.

Belt wheel 20 is intended merely to bonding ribbon 11 with the example of the endless drive member engagement member of tension force in retainer belt 11. Alternative endless drive member engagement member can include for example being fixedly mount to tensioner arms 14 and be sliding engaged band 11 brake shoe.Bearing 18 will not be included in this embodiment, and be therefore related to prevent or promote oil stream to bearing appoint What structure is also unwanted.

Although above description constitutes multiple embodiments of the present invention, it is understood that, without departing substantially from appended power In the case of the reasonable implication that profit requires, the present invention allows further modifications and changes.

Claims (20)

1. a kind of stretcher for being used to be tensioned endless drive member, the stretcher include：

Base portion, the base portion include pivot, spring cup and back plate, wherein, the pivot has base end part and distal portion, and limits Pivotal axis is determined, the pivot has to be allowed for pacifying the stretcher through its pivot aperture, the pivot aperture The installation fastener for being filled to fixed structure passes through, wherein, the spring cup is fixedly connected to the pivot and with axially Ground and the spring tegmental wall extended circumferentially over upon, the spring tegmental wall have inner radial surface and radially-outer surface, and wherein, institute Back plate is stated to be fixedly connected to the pivot and be configured for determining the base portion relative to the fixed structure To；

Tensioner arms, the tensioner arms are pivotally mounted on the pivot to be moved pivotally around the pivotal axis；

Pivot bushings, the pivot bushings are positioned between the tensioner arms and the pivot, wherein, the pivot bushings is consolidated Surely one of the pivot and the tensioner arms, and the pivot bushings and the pivot and the tensioning are connected to The other of device arm frictionally engages；

Endless drive member engagement member, the endless drive member engagement member are attached to the tensioner arms and are positioned to Engage the endless drive member；And

Spring, the spring are positioned to urge the tensioner arms along tightening up direction,

Wherein, the tensioner arms have the skirt axially and extended circumferentially over upon, and the skirt has radial direction appearance Face and inner radial surface, wherein, the skirt is axially overlapping axially to impale spring housing with the spring tegmental wall, its In, one of the spring tegmental wall and the skirt surround the other of the spring tegmental wall and described skirt,

Wherein, from the another one in the spring tegmental wall and the skirt towards the spring tegmental wall and the skirt In the one extend radially outwardly and have at least one guide wall, wherein, at least one guide wall and the spring cup The one in wall and the skirt do not contact and with the another one in the spring tegmental wall and the skirt Separate selected gap.

2. stretcher according to claim 1, wherein, the endless drive member engagement member is belt wheel, the belt wheel The tensioner arms are rotatably mounted to via bearing to be rotated around the belt wheel axis separated with the pivotal axis.

3. stretcher according to claim 1, wherein, at least one guide wall includes axially adjacent each other two Guide wall.

4. stretcher according to claim 1, wherein, each guide wall includes base portion side and distal face, and its In, the base portion side substantially radially extends.

5. stretcher according to claim 4, wherein, the distal face is at an oblique angle towards the base portion side face diameter To stretching out.

6. stretcher according to claim 1, wherein, the spring cup separates with the back plate and has base end part, The base end part is rounded and engages and coordinates with the back plate to form the spring cup extended circumferentially over upon around the spring cup Oil releases passage.

7. stretcher according to claim 1, wherein, it is provided through the spring tegmental wall and from the spring cup The groove that the base end part axially extends, wherein, the first end of the spring of the stretcher extends through the groove with relative The first end of the spring is fixed in the base portion, and wherein, the groove is positioned in the stretcher and is attached to Being sentenced during the fixed structure positioned at the bottom of the spring cup enables the oil in the spring cup to be passed through by means of gravity The groove leaves the spring cup.

8. stretcher according to claim 1, wherein, the skirt surrounds the spring tegmental wall, and wherein, it is described The first oil for having circumferentially extending on the radially-outer surface of spring tegmental wall releases passage, and first oil releases passage relative to institute State at least one guide wall be in base portion, wherein, first oil releases channel location into capturing the outer of the spring tegmental wall Oil on surface is moved with suppressing oil at least one guide wall.

9. stretcher according to claim 1, wherein, the skirt surrounds the spring tegmental wall, and the skirt Portion has skirt outer surface, and the skirt outer surface has base end part, wherein, the outer surface of the skirt is remote The base end part is distad tapered, wherein, there is the outer surface away from the skirt to radially extend simultaneously for the outer surface The skirt guide wall separated with the base end part of the skirt.

10. stretcher according to claim 9, wherein, the endless drive member engagement member is belt wheel, the belt wheel The tensioner arms are rotatably mounted to be rotated around the belt wheel axis separated with the pivotal axis via bearing,

And wherein, the skirt be positioned at the bearing base end part sentence so that the skirt guide wall suppress oil connect The base end part of the bearing is touched,

And wherein, the stretcher also includes the thrust washer for being fixedly connected to the distal portion of the tensioner arms, wherein, The thrust washer is radially into the distal portion for substantially covering the bearing.

11. stretcher according to claim 7, wherein, the back plate has loop portions, the loop portions and the pivot Radially-outer surface be fixedly engaged and extend in the inner space of the spring cup, wherein, have in the loop portions Circumferential lips, the base interface region between the lips and the spring cup are distad separated to form loop portions oil Passage is released, wherein, when the stretcher is arranged on the fixed structure, the loop portions oil, which releases passage, has positioning In the bottom of the surface of the groove.

12. stretcher according to claim 11, wherein, the loop portions oil, which releases passage, has the surface of oleophobic.

13. stretcher according to claim 1, wherein, the pivot on the base portion of the pivot bushings and distal end On radially-outer surface be oleophobic.

14. stretcher according to claim 9, wherein, outside the skirt on the distal end of the skirt guide wall Surface is oleophobic.

15. stretcher according to claim 2, wherein, the bearing includes inner ring and outer ring, and the bearing is in institute State not to suppress the distal side protective cover and base portion side protective cover that oil is moved into the bearing between inner ring and the outer ring,

Wherein, the skirt around the spring tegmental wall and has skirt outer surface, and the skirt outer surface has With the inner ring of the bearing in the adjacent distal portion of base portion, and there is base end part, wherein, the skirt it is described outer Base portion side of the surface away from the base end part towards the bearing is distad tapered.

16. stretcher according to claim 15, wherein, the stretcher also includes thrust washer, the thrust washer It is fixedly connected to the distal portion of the tensioner arms and is positioned to adjacent in distal side with the bearing, wherein, the thrust Packing ring extends radially outwardly into the inner ring beyond the bearing, and wherein, the thrust washer has in base portion side court The radial edges tapered to the bearing.

17. stretcher according to claim 15, wherein, the outer surface of the skirt the distal portion with Interface between the inner ring of the bearing is oleophylic.

18. stretcher according to claim 16, wherein, between the thrust washer and the inner ring of the bearing Interface be oleophylic.

19. stretcher according to claim 1, wherein, the gap is in the range of no more than about 0.5 millimeter.

20. stretcher according to claim 1, wherein, the pivot bushings is fixedly connected to the tensioner arms simultaneously And it is frictionally engaged with the radially-outer surface of the pivot.