CN1107176C - Assembly structure of chain lead part - Google Patents

Abstract

The present invention relates to the construction of a chain guide. A chain chamber(5)of a crankcase(1)is formed by die drawing, and at the same time, a supporting recess(20)opened in spreading in the die drawing direction is formed, and the sliding end(18)of a chain guide(15)bent approximately in a bow and formed from a resin in the whole construction is inserted from the opening in the chain chamber(5)and fitted in the recess(20). At the left and right of the other end of the chain guide(15), projections(40, 41)having different projecting lengths are formed in a single piece, and are fitted in and supported by supporting grooves(32, 33)having different fit widths formed in the supporting wall of a cylinder block(2). The support of the chain guide(15)on the chain chamber(5)is made only in two places, i.e., a projection locating/fixing part(22)and the sliding end(18), and because the force exerted by a cam chain(10)is received by a long span and at the same time, the sliding end(18)can make sliding freely, the follow-up performance after the cam chain is enhanced. When the chain guide(15)is assembled reversely, the projections(40)are not able to be fitted in the respective grooves(32), and thus the risk of reverse assembling is precluded.

Description

The mounting construction of chain lead part

The present invention relates to the mounting construction of the chain lead part that 4 two-stroke engine valve mechanisms use.

The Japanese Patent Application Publication communique is real to be opened in clear 58-31460 number, has disclosed the valve mechanism of 4 two-stroke engines.Be used to push the chain lead part of the cam chain that constitutes this valve mechanism, the whole slightly straight line shape that forms of the slide part that itself and chain slide, simultaneously, an end is closely chimeric to be bearing in the supporting recess (this supporting recess is formed in the crankcase of chain chamber), and the intermediate portion of the other end is bearing in the wall portion of chain chamber.The Japanese Patent Application Publication communique is real to be opened in flat 1-148154 number, has also disclosed the chain lead part of same structure.Above-mentioned chain lead part all is that sintering rubber forms guiding face on metal core.Japanese Patent Application Publication communique spy opens the chain lead part that discloses for clear 60-104843 number, and Lower Half is integrated with the metallic core, and only the first half is made rubber, and by the projection that is wholely set, it is indoor to be bearing in chain in a plurality of positions contacts.

In order to improve servo-actuated to cam chain action, and, in order to prevent high vibrating noise, preferably the whole chain guide member is made with resin.But the attenuate intensity of for this reason must trying one's best is weaker than the resin of metal, to improve servo-actuated.And in order to improve intensity, attenuate unrestrictedly again.Therewith relatively,, consider a part is thickened, realize varied in thickness in order to be prevented the anti-structure of dress easily.But therefore the requirement of so having violated above-mentioned attenuate again needs other structure.And during as sliding end, if improve whole servo-actuated, the wearing and tearing of this sliding end are big an end, so, also wish to improve the wear-resistant of this part.The objective of the invention is to satisfy above-mentioned requirements.

In order to solve above-mentioned problem, the mounting construction of chain lead part of the present invention, it is indoor that the pushing engine air valve device is housed in chain with the chain lead part of cam chain,, with the chimeric swingably wall portion that is bearing in the chain chamber in an end of chain lead part the other end of chain lead part is entrenched in the supporting recess in the crankcase of being located at bottom, chain chamber with outstanding a pair of positioning and fixing portion to the left and right; It is characterized in that:

By towards slightly being parallel to the chain chamber that the demoulding of cam chain surface of revolution direction forms crankcase, simultaneously, expand towards stripping direction that open ground is whole to form above-mentioned supporting recess, the above-mentioned the other end of chain lead part is entrenched in this supporting recess as the slip end is loosening slidably;

The supporting construction with respect to the chain chamber of above-mentioned positioning and fixing portion, become have an asymmetric chimeric mechanism in the left and right sides prevent to adorn anti-structure;

Whole chain guide member ester moulding bends to slightly arcly side-prominently towards cam chain, it is indoor with above-mentioned positioning and fixing portion and slip end chain lead part to be bearing in chain.

According to the present invention, with ester moulding whole chain guide member and curve slightly arc, with an end as sliding end, it is indoor to be bearing in chain with positioning and fixing portion and slip end, so, sustain power with long span from cam chain, can avoid stress to concentrate, do chain lead part thinner, can improve servo-actuated, and can prevent high vibrating noise cam chain.

In addition, by forming the chain chamber of crankcase towards the demoulding of slightly parallel cam chain surface of revolution direction, and in its formation, become the supporting recess towards the stripping direction open terrain, so, can make supporting recess smooth interior surfaces, improve the loosening wearability that is entrenched in the slip end here.And, can dispense the level and smooth processing of supporting recess internal surface, or make this level and smooth simplified processing easily by demoulding shaping chain chamber and supporting recess.

In addition, insert the sliding end of chain lead part from top, chain chamber, chimeric being bearing in the supporting recess, though dress is anti-easily during this assembling operation, because positioning and fixing portion prevents to adorn anti-structure with respect to chain locular wall portion, so, can not adorn instead, re-assembly even adorned anti-also to find immediately.In addition, prevent to adorn anti-structure owing to use with respect to the asymmetrical chimeric mechanism in the left and right sides, chain chamber formation, so, needn't locally thicken chain lead part, can improve servo-actuated.

Accompanying drawing is simply described as follows:

Fig. 1 be embodiment be suitable for start chain chamber overall diagram.

Fig. 2 is the chain chamber sectional view along 2-2 line among Fig. 1.

Fig. 3 is the plan view of cylinder block.

Fig. 4 is the planimetric map of chain lead part.

Fig. 5 is the profile of chain lead part.

Fig. 6 is the 6-6 line amplification profile diagram of Fig. 3.

Fig. 7 is the 7-7 line amplification profile diagram of Fig. 4.

Below, be used for the embodiment of valve mechanism of 4 two-stroke engines of motor bike with reference to description of drawings.Fig. 1 be embodiment be suitable for start chain chamber overall diagram.Fig. 2 is the chain chamber sectional view along 2-2 line among Fig. 1.Fig. 3 is the plan view of cylinder block.Fig. 4 is the planimetric map of chain lead part.Fig. 5 is the profile of chain lead part.Fig. 6 is the 6-6 line sectional view of Fig. 3.Fig. 7 is the 7-7 line sectional view of Fig. 4.

At first, with reference to Fig. 1 valve mechanism integral body is described.This motor is overlapping the assembling of order according to crankcase 1, cylinder block 2, cylinder head 3, cylinder skull 4.In the top of the cylinder head 3 that is covered with by cylinder skull 4, accommodating the cam portion that figure does not show.

Between these crankcases 1, cylinder block 2, cylinder head 3, cylinder skull 4, form continuous poroid chain chamber 5 abreast with cylinder-bore axis C, in this chain chamber 5, stretch out in crankcase 1 part an end of bent axle 6, and driving sprocket wheel 7 is installed on this extension.

Camshaft 8 is bearing in the cylinder skull 4, and the one end stretches out in chain chamber 5, and driven sprocket 9 here is installed, be wound onto and the cam chain 10 of 7 of driving sprocket wheels as shown by arrows, towards with driving sprocket wheel 7 equidirectional rotary driving.

Cam chain 10 is made of silent chain, and in order to eliminate lax between driving sprocket wheel 7 and the driven sprocket 9, chain tensioning device 11 is from foreign side's pushing of slack-side.

Chain tensioning device 11, one end bearing portion 12 is entrenched in the recess 13 (this recess is formed in the crankcase 1 wall portion) as point supporting, and the other end is a free end, and intermediate portion is conditioned device 14 and pushes towards cam chain 10 directions.

The stretch-draw side that chain lead part 15 is urged at cam chain 10 is the opposition side of chain tensioning device 11.Chain lead part 15, intermediate portion slip that face 16 is urged and outstanding towards cam chain 10, and it is slightly arc that integral body curves, and the opposing face that slips face 16 is as the back side 17.

One end of chain lead part 15 slightly is 17 bendings towards the back side of く font ground as slip end 18 with inflection point 19, chimeric being bearing in the supporting recess 20, and this supporting recess 20 is formed in the chain chamber 5 of crank box 1.The other end 21 of chain lead part 15 is free ends, is provided with positioning and fixing portion 22 in its vicinity, and is fixing by the chimeric support 23 that is located on the cylinder block 2.

As shown in Figure 2, the chain chamber 5 of crankcase 1 is by punch die (order I type) 25 shapings, this punch die 25 is towards the cylinder-bore axis C direction demoulding of the surface of revolution that slightly is parallel to cam chain 10, be formed on bag shape with joining portion face 26 upper sheds of cylinder block 2, at this moment support recess 20 and also be shaped simultaneously, form towards stripping direction and expand open summary U font recess.

As shown in Figure 1, the opening portion 27 of supporting recess 20 can chimeric like a cork slip end 18 greater than bottom 28, simultaneously, even form with the dress opposite state also can be chimeric when chimeric shape, and flexure planes are formed on bottom 28, are slided easily in slip end 18.The support that label 29a among Fig. 2,29b are bent axle.

As shown in Figure 3, cylinder block 2 forms chain chamber 5 abreast in the side of cylinder 30, near the position in opposite directions the mating face 31 this chain chamber 5 and cylinder head 3, form and a pair ofly slightly be the recessed support slot 32,33 of U font towards the cylinder block direction, towards the mating face 31 and chain chamber 5 open.

Support slot 32,33 constitutes chimeric support 23, and as shown in Figure 6, the length of the sidewall 34,35 of the chain chamber 5 in the recessed cylinder block 2 is that chimeric width D 1 and D2 are inequality, is D1＜D2 in this embodiment.

Support slot 32,33, its depth d is all identical with opening portion width w (Fig. 3), and depth d and width w are onesize.In addition, each opening portion of the support slot 32,33 in the mating face 31 when engaging with cylinder head 3, is covered by near cap integrally formed mating face 36 37.

As shown in Figure 4, the positioning and fixing portion 22 of chain lead part 15 is made of a pair of circular shaft shape teat 40,41.This teat 40,41 forms from the long leg in opposite directions of chain lead part 15 is outstanding integratedly to the left and right.

As shown in Figure 7, the thickness of each teat 40,41 is identical with each width w of support slot 32,33, but outstanding length L 1 and L2 are L1＜L2, corresponding with separately D1, D2, teat 40 is fitted in the support slot 32, teat 41 is fitted in the support slot 33, and long teat 41 and support slot 33 are only selectively chimeric when this makes up.

Chain lead part 15 comprises teat 40,41 and forms as one by having suitable stiff and flexible synthetic resin constitutes, and it slips face 16 on the width that cam chain 10 passes through, and becomes along the bottom surface of the groove 42 of total length roughly.

Below, the effect of present embodiment is described.When this chain lead part 15 is installed, earlier cylinder block 2 is overlapped on the crankcase 1, make chain chamber 5 alignment separately, simultaneously, from the top of cylinder block 2 chain chamber 5 is put in the slip end 18 of chain lead part 15, and chimericly go into to support in the recess 20, teat 40 and teat 41 are entrenched in respectively in support slot 32 and the support slot 33.

At this moment, if slip face 16 towards the outside, the back side 17 towards cam chain 10 ground with chain lead part 15 dress inverse time since length is teat 41 and the length of L2 be the support slot of D1 32 inconsistent (L2＞D1) and can not be chimeric, so, can find immediately be adorn anti-, operation again.

Then, cylinder head 3 is overlapped on the cylinder block 2, cover each top of support slots 32 and support slot 33 with the cap 37 of cylinder head 3, so, fixedly teat 40 and teat 41, the result can constitute with fairly simple structure and prevent to adorn anti-structure.Therefore, open, can form chain chamber 5 easily, adorn the structure that anti-possibility increases, but can correctly prevent anti-installation of dress although form by supporting recess 20 is expanded towards stripping direction.

In addition, the slip surface of the bottom 28 that is shaped by the die face of punch die 25 is level and smooth, can make the slip of sliding end portion 18 flexible, improves its wearability simultaneously.In addition, can dispense the surface smoothing processing of bottom 28, perhaps make this level and smooth simplified processing easily with the supporting recess 20 of punch die shaping chain chambers 5 25 and slip end 18.

In addition, it is slightly arc that whole chain guide member 15 is curved towards cam chain 10 1 side-prominently, is bearing on the chain chamber 5, simultaneously by positioning and fixing portion 22 and slip end 18, slip end 18 is entrenched in the supporting recess 20 slidably, so 15 pairs of cam chains 10 of chain lead part apply pushing force, can prevent the vibration of cam chain 10, simultaneously, by being the swing of fulcrum and the slip of slip end 18 with positioning and fixing portion 22, can follow the vibration of cam chain 10 and change, can obtain good servo-actuated.

At this moment, be supported on the supporting point of chain chamber 5, only be positioning and fixing portion 22 and slip end 18 such 2 points, so, bear power with long span from cam chain 10, can avoid stress to concentrate, also can do chain lead part 15 thinner in this, can improve servo-actuated cam chain 10.

And, prevent to adorn anti-structure owing to use to constitute with respect to the asymmetrical chimeric mechanism in 5 left and right sides, chain chamber, so, will chain lead part 15 parts not do thickly, this point also can improve servo-actuated.

In addition, whole chain guide member 15 is bent to slightly arc, can prevent easily that also dress is anti-.In addition, owing to whole make with resin, but weight reduction prevents high vibrating noise, and simultaneously, frictional force is littler than rubber, so, also improved durability with the slip surface of cam chain 10.

In addition, prevent to adorn anti-structure and be not limited to the foregoing description, can do various distortion.For example, also can form recess, form the protuberance that embeds this recess in cylinder block 2 sides in chain lead part 15 sides.In addition, not only change the length of left and right sides embedding part, also make the chimeric section difference in the left and right sides, like this, even the identical dress that also can prevent in the embedding part length left and right sides is anti-.

In addition, owing to use the chain chamber that forms crankcase towards the punch die that slightly is parallel to the demoulding of cam chain surface of revolution direction, and in its formation, formation is towards the open supporting recess of stripping direction, so, can make supporting recess smooth interior surfaces, improve the loosening wearability that is entrenched in the slip end here.

Claims (1)

1. the mounting construction of a chain lead part, it is indoor that the pushing engine air valve device is housed in chain with the chain lead part of cam chain,, with the chimeric swingably wall portion that is bearing in the chain chamber in an end of chain lead part the other end of chain lead part is entrenched in the supporting recess in the crankcase of being located at bottom, chain chamber with outstanding a pair of positioning and fixing portion to the left and right; It is characterized in that:

By towards slightly being parallel to the chain chamber that the demoulding of cam chain surface of revolution direction forms crankcase, simultaneously, expand towards stripping direction that open ground is whole to form above-mentioned supporting recess, the above-mentioned the other end of chain lead part is entrenched in this supporting recess as the slip end is loosening slidably;

The supporting construction with respect to the chain chamber of above-mentioned positioning and fixing portion, become have an asymmetric chimeric mechanism in the left and right sides prevent to adorn anti-structure;

Whole chain guide member ester moulding bends to slightly arcly side-prominently towards cam chain, it is indoor with above-mentioned positioning and fixing portion and slip end chain lead part to be bearing in chain.

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