CN1711433A

CN1711433A - Tensioner

Info

Publication number: CN1711433A
Application number: CN 200380102853
Authority: CN
Inventors: 井上史久; 高桥郁臣; 天野种平
Original assignee: NHK Spring Co Ltd
Current assignee: NHK Spring Co Ltd
Priority date: 2002-11-01
Filing date: 2003-10-30
Publication date: 2005-12-21
Anticipated expiration: 2023-10-30
Also published as: CN100491771C; WO2004040167A1; AU2003277533A1; BR0315877A; JPWO2004040167A1

Abstract

Portions of a tensioner that affect braking force and other characteristics to the maximum extent wear less with operating time. Further, the braking force and other characteristics of the tensioner are affected less by varying lubricating conditions. As a result, the tensioner is capable of providing stable characteristics for a long period. A tensioner is characterized in that it has a case; a rotating body that is rotatably received in the case so as not to be movable in an axial direction; a pressing body that is screwed to the rotating body, movable in the axial direction, prevented from rotating relative to the case, and to which a load in the axial direction is applied from a force-transmitting member; and a spring that is received inside the case and applies a rotational force to the rotating body; where the rotating body is rotatably supported at its shaft portion by a supporting portion of the case and supports the load acting on the pressing body, and the pressing body is prevented from rotating by a bearing. The tensioner is further characterized in that, out of the surfaces of the rotating body, a shaft portion of the rotating body, the supporting portion of the case, the pressing body, and the bearing, at least the surface of the shaft portion of the rotating body is provided with a film of a ternary alloy of nickel, phosphorus, and tungsten, or a film of a ternary alloy of nickel, phosphorus, and boron.

Description

Stretcher

Technical field

The present invention relates to a kind of stretcher, it is will predetermined tension force to be applied on the force transmission elements such as chain that engine cam is driven or timing cingulum, and this motor is carried for example 4 is taking turns on the vehicles such as automobile or two-wheel car.

Background technique

Even stretcher is used for making chain or timing cingulum in use also can keep roughly certain force of strain because of stretching or wearing and tearing to produce under the lax situation.General stretcher in the past has as shown in Figure 6: housing 101; Solid of rotation 102 has outer screw section 102a; Pushing body 103 has the 103a of female thread portion that the outer screw section 102a with this solid of rotation 102a screws togather; Spring 104, to solid of rotation 102 to the 1st sense of rotation application of force; Bearing 109 is used for retraining the rotation of pushing body 103; Or the like.If solid of rotation 102 to the 1st direction rotation, then pushes body 103 and moves along axial direction under the effect of above-mentioned spring 104.Solid of rotation 102 is housed in the housing 101, and the end face 102b of solid of rotation 102 rotates freely that the earth's axis is supported on the supporting surface 101b of housing 101.

This stretcher by above-mentioned spring 104 by the spring-back force when the direction opposite with the 1st sense of rotation reversed, accumulated, to solid of rotation 102 to the 1st sense of rotation application of force.Under the effect of this rotating torques, pushing body 103 is to moving from housing 101 outstanding axial directions, and the front end of pushing body 103 pushes force transmission elements such as chain or timing cingulum directly or indirectly.And if the tension force of chain or timing cingulum increases, the power of then anti-pushing body 103 becomes big.At this moment, overcome the summation of torque of frictional resistance of the supporting surface 101b of the end face 102b of surface friction drag between the application of force based on above-mentioned spring 104, above-mentioned outer screw section 102a and the 103a of female thread portion and solid of rotation 102 and housing 101, pushing body 103 is pushed back to the axial direction towards the inside of housing 101.Stretcher can apply certain force of strain to chain or timing cingulum according to these torques etc.

This stretcher in the past can cause the bigger variation of the braking force of stretcher because of the wearing and tearing that are accompanied by process service time, the variation of lubricating status.So, login in No. 2120655 in Japanese Utility Model and to have proposed:, the outer screw section 9 and the female thread portion 13 of solid of rotation 2 and pushing body 3 carried out the surface treatment of Ka Ningjien chemical nickel plating uniform wearability as the technology that addresses this is that.

But, in the wear resistance surface treatment of Ka Ningjien chemical nickel plating in the past, under the situation that variable load is big, vibration is violent that acts on the stretcher, also exist processing layer to wear and tear, cause the problem of durability such as braking force variation along with the process of service time.

The present invention proposes in view of this problem, its objective is provide a kind of can prevent to braking force and properties influence the best part along with service time process wearing and tearing and the variation of the variation of the variation of lubricating status, braking force and characteristic less, demonstrate long-time stability can stretcher.

Summary of the invention

Stretcher of the present invention has: housing; Solid of rotation, rotatable and under being limited the state that moves of axial direction, be housed in this housing; The pushing body screws togather with this solid of rotation, can move to axial direction, and restrained with respect to the rotation of above-mentioned housing, the load of axial direction is applied to it from force transmission element; And spring, be housed in the inside of above-mentioned housing, and above-mentioned solid of rotation is applied rotating force; The axial region rotation of above-mentioned solid of rotation is supported on the support of above-mentioned housing freely, thereby is supporting the above-mentioned load that acts on the above-mentioned pushing body, and the rotation of above-mentioned pushing body is retrained by bearing;

It is characterized in that, in the surface of support, pushing body and the bearing of the axial region of above-mentioned solid of rotation, solid of rotation, housing, at least on the surface of the axial region of solid of rotation, be formed with the overlay film of 3 yuan of alloys of nickel, phosphorus, tungsten, perhaps the overlay film of 3 yuan of alloys of nickel, phosphorus, boron.

Being used to advance the solid of rotation of pushing body is important motion key element, the axial region of solid of rotation is supported by the support of housing, by the rotation of solid of rotation at the support place of housing, perhaps counter-force acts on the solid of rotation via the pushing body, makes excessive load act on the axial region of solid of rotation.Therefore, though produced wearing and tearing and surface friction drag, the present invention so wear and tear and the rare variation of surface friction drag, obtains stable performance owing to be formed with the overlay film of 3 yuan of alloys of nickel, phosphorus, tungsten at least at the axial region of solid of rotation.

According to stretcher of the present invention, can keep for a long time because of wearing and tearing or the variation of the braking force (frictional force) that causes of the variation of lubricating status and the less stable performance of variation of characteristic along with process service time.

Description of drawings

Fig. 1 is the sectional view of the stretcher of expression embodiments of the present invention.

Fig. 2 is the sectional view of a part of the motor that makes use-case of expression stretcher.

Fig. 3 is the part amplification view of axial region of the situation of the expression overlay film that forms 3 yuan of alloys.

Fig. 4 is the plotted curve of experimental result of the relation of expression aging temp and hardness.

Fig. 5 is the plotted curve of experimental result of the relation of expression transit time and retarding torque.

Fig. 6 is the sectional view of example in the past of expression stretcher.

Embodiment

Illustrate in greater detail the present invention with reference to the accompanying drawings.

Fig. 1 is the sectional view of stretcher of expression embodiments of the present invention, and Fig. 2 is the sectional view of a part of the motor that makes use-case of expression stretcher.

This stretcher uses in the power transmission mechanism 201 of engine for automobile for example shown in Figure 2 200.Power transmission mechanism 201 passes to camshaft 203 with rotatablely moving of motor 200 via jointless force transmission elements 202 such as timing cingulum or chains, therefore, this stretcher is installed on the precalculated position of motor 200, by thrust described later force transmission element 202 is pushed to the direction shown in the arrow V, (fix) and tension force is remained necessarily.

Stretcher shown in Figure 1 has: housing 1 is formed with axial blank part 1a; Solid of rotation 2 and pushing body 3 are inserted into the state of screwing togather among the blank part 1a of housing 1; Torsion spring 4 applies rotating force to solid of rotation 2; Bearing 5 is installed on the front end of housing 1, the rotation of constraint pushing body 3; Retractile bellows 6 is coated on the part between housing 1 and the pushing body 3.The rearward end of pushing body 3 is inserted in the inside of housing 1, and front end is projected into the outside of housing 1.On the opening of the base end part of housing 1, screwing togather sealing bolt 8, keeping the tightness of base end part one side via sealing gasket 7.

On the front part of solid of rotation 2, be formed with outer screw section 9, on the inner peripheral surface of the pushing body 3 of hollow, be formed with female thread portion 13, screw togather mutually by this female thread portion 13 and outer screw section 9, solid of rotation and pushing

body

2,3 can be rotated relative to each other and can be installed together progressively to axis X direction spiral.

The solid of rotation 2 of above-mentioned installment state and pushing body 3 are inserted in the helical spring 4.This spring 4 extends in the direction along the axis X of solid of rotation 2, pushing body 3, and an end 4a of spring 4 is inserted in the slit 12 of solid of rotation 2.This slit 12 is along the axis X direction of solid of rotation 2.Another end 4b card of spring 4 ends on housing 1, or card ends on the bearing 5 that is installed on the housing 1.Like this, two end part 4a, the 4b card with spring 4 ends on solid of rotation 2 and housing 1.The front end that will rotate the anchor clamps (for example screw-driver) of usefulness under the state that sealing bolt 8 is pulled down from the outside of housing 1 is inserted into the above-mentioned slit 12, solid of rotation 2 is rotated around axis X, then, make spring 4 put aside the energy (torque) that solid of rotation 2 is rotated round about by spring 4 is reversed.

Be provided with bearing 5 on the fore-end of housing 1, this bearing 5 is fixed on the housing 1 by for example encircling spring 15 component for fixing such as grade.Be formed with non-circular sliding eye 5a on bearing 5, pushing body 3 is inserted and is led in this sliding eye 5a.The sliding eye 5a of the corresponding bearing 5 of outer circumferential face of pushing body 3 and be formed non-circular shape, chimeric by this pushing body 3 with sliding eye 5a of bearing 5, retrain of the rotation of pushing body 3 with respect to housing 1.On the front end of pushing body 3, cap 14 is installed.This cap 14 directly or via relay part is connected on the timing cingulum or chain as force transmission element 202 indirectly.

If make solid of rotation 2 rotate, reverse above-mentioned spring 4 to the 2nd direction, then the elastic potential energy of spring 4 makes solid of rotation 2 rotate to the 1st direction.This rotation passes to pushing body 3 via

screw section

9,13, pushing force 3 restrained rotation owing to the effect that is subjected to bearing 5 is so the rotating force of solid of rotation 2 is converted into the propelling force to the axis X direction of pushing body 3.Therefore, pushing body 3 is to advancing from housing 1 outstanding direction.

On the other hand, the load Z that applies from the force transmission element 202 of timing cingulum or chain etc. inputs to pushing body 3, will push body 3 and push to the axis X direction.Pass to solid of rotation 2 by this pushing force via

screw section

9,13, solid of rotation 2 overcomes the application of force of spring 4 and rotates to the 2nd direction.By the rotation of this direction, pushing body 3 is pushed back in housing 1.By these actions, the tension force of force transmission element can be remained roughly certain.

Solid of rotation 2 forms, the setting that is connected of the axial region 10 of the outer screw section 9 of front end one side and base end part one side, and axial region 10 is supported in the support 11 of housing 1, can be rotated support.The axial region 10 of solid of rotation 2 is formed than the bigger large-diameter portion of screw section 9 diameters, and the supporting surface 17 of the support 11 of housing 1 is adjacent with the end face 16 of the axial region 10 that is somebody's turn to do big footpath.The end face 16 of the axial region 10 of solid of rotation 2 contacts with the supporting surface 17 of the support 11 of housing 1, and the supporting surface 17 that inputs to supported 11 of the above-mentioned load Z of pushing body 3 supports.

And, on the axial region 10 of above-mentioned solid of rotation 2, be formed with the overlay film of 3 yuan of alloys of nickel, phosphorus, tungsten.The overlay film of these 3 yuan of alloys is to form by the coating that 3 yuan of alloys implementing by nickel, phosphorus, tungsten constitute.Fig. 3 is the enlarged portion sectional view that is illustrated in the situation of the overlay film 22 that has formed 3 yuan of alloys on the axial region 10 of solid of rotation 2.These 3 yuan of alloys also can be with nickel, phosphorus, tungsten beyond 3 yuan of alloys of element.For example can enumerate 3 yuan of alloys of nickel, phosphorus, boron.

In this stretcher, because of the wearing and tearing of following process service time and the variation of lubricating status, friction torque can change, and has greatly changed on performance.We think that this and following reason have very big relation.

(1) wearing and tearing that bring of the surface friction drag between the application of force of spring 4 and above-mentioned outer screw section 9 and the female thread portion 13 and the variation of surface friction drag;

(2) on the support 11 of the housing 1 of the axial region 10 of rotating body for supporting 2, by solid of rotation 2 rotations, perhaps counter-force (Reversal り power) acts on the solid of rotation 2 via pushing body 3, and excessive load is acted on axial region 10 and the support 11, and wearing and tearing and surface friction drag change;

(3) at the butt position of bearing 5 and housing 1, the rotating force of spring 4 passes to the bearing 9 of the rotation of constraint pushing body 3, and crimp force acts on the above-mentioned butt position, and weares and teares.

But, being used for advancing the rotation of the solid of rotation 2 that pushes body 3 is important motion key elements, the axial region 10 of solid of rotation 2 is because supported by the support 11 of housing 1, so the reason of above-mentioned in the characteristic variations (2) is bigger as can be known, in this embodiment, because be formed with the overlay film of 3 yuan of alloys of nickel, phosphorus, tungsten on the axial region 10 of solid of rotation 2, so it is less to wear and tear, surface friction drag does not change yet.Thus, friction torque can not take place than cataclysm, and characteristic can not produce bigger variation, becomes stable properties in long-time.This for the overlay film of 3 yuan of alloys of nickel, phosphorus, boron too.

From this point, be preferably the overlay film that not only on support 11, also forms 3 yuan of alloys on the axial region 10 of solid of rotation 2, at housing 1, most preferably be, taking place on the parts of above-mentioned (1)～(3), promptly all forming the overlay film of above-mentioned 3 yuan of alloys on all surface such as the axial region 10 of the support 11 of housing 1, solid of rotation 2, solid of rotation 2, pushing body 3 and bearing 5.But if aspects such as the effect of considering and costs, the overlay film that then forms 3 yuan of alloys at least on the axial region 10 of solid of rotation 2 just can.

Use nickel, phosphorus, tungsten in the present invention, or the overlay film of 3 yuan of alloys of nickel, phosphorus, boron, be based on following reason.

(1) be 3 yuan of alloys, what do not have that dispersed state brings is inhomogeneous.

(2) can make under stable heat-treat condition, coating hardness is stable.

(3) owing to stable in the heat treatment under the lower temperature, so oxidation and few to the influence of material.

(4) sealing is higher, uniform film thickness.

(5) coating hardness is higher, wearability is better, and lubricating status is few to the influence of braking force (surface friction drag) in long-time.

Fig. 4 is the plotted curve of experimental result of the relation of expression aging temp and hardness.According to this Fig. 4, under the situation of 3 yuan of alloys of nickel, phosphorus, tungsten, hardness is stable near 350 ℃ as can be known, than nickel, phosphorus alloy hardness height.Under the situation of nickel, phosphorus alloy, hardness is stable near 400 ℃.

Fig. 5 is the plotted curve of experimental result of the relation of expression transit time and retarding torque.According to this Fig. 5 as can be known, it is lower that enforcement product of the present invention and the product in the past of the overlay film of having implemented nickel, phosphorus alloy of having implemented the overlay film of nickel, phosphorus, tungsten compared retarding torque, with low uncertainty along with effluxion.

In addition, above-mentioned mode of execution does not limit the invention, and the present invention can do various variations in the scope that does not break away from purport.

Industrial applicibility

As known from the above, even stretcher of the present invention is used for making chain or timing belt using In because stretching or wearing and tearing produce in the situation about relaxing and also can keep roughly certain tension force, because of This is such as drive carrying the camshaft of taking turns the engine on the vehicles such as automobile or two-wheel car 4 Chain or timing belt etc. in use, have practicality.

Claims

1, a kind of stretcher has: housing; Solid of rotation, rotatable and under being limited the state that moves of axial direction, be housed in this housing; The pushing body screws togather with this solid of rotation, can move to axial direction, and restrained with respect to the rotation of above-mentioned housing, the load of axial direction is applied to it from force transmission element; And spring, be housed in the inside of above-mentioned housing, and above-mentioned solid of rotation is applied rotating force; The axial region rotation of above-mentioned solid of rotation is supported on the support of above-mentioned housing freely, thereby is supporting the above-mentioned load that acts on the above-mentioned pushing body, and the rotation of above-mentioned pushing body is retrained by bearing; It is characterized in that,

In the surface of support, pushing body and the bearing of the axial region of above-mentioned solid of rotation, solid of rotation, housing, on the surface of the axial region of solid of rotation, be formed with the overlay film of 3 yuan of alloys of nickel, phosphorus, tungsten at least, perhaps the overlay film of 3 yuan of alloys of nickel, phosphorus, boron.