CN2523954Y

CN2523954Y - Automatic pressure reducer

Info

Publication number: CN2523954Y
Application number: CN 01265647
Authority: CN
Inventors: 冯斌
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-09-26
Filing date: 2001-09-26
Publication date: 2002-12-04
Anticipated expiration: 2011-09-26

Abstract

An automatic pressure reducer of the utility model is used for a four-cycle engine. A non-reversing wheel and an anti-centripetal weight are arranged on a cam axle. A circular arc groove is arranged on the outer circumference of the non-reversing wheel. A shifting fork is fixedly arranged on the stopper of the airframe. The shifting fork can contact with the return spring and the spacing spring simultaneously. The anti-centripetal weight connects with the cam axle through an anchor pin. The anti-centripetal weight can move up and down respectively under the function of the anti-centripetal spring force and the centrifugal effort. The anti-centripetal weight dummy club also moves up and down with the anti-centripetal weigh, which decides that whether the anti-centripetal weight dummy club contacts the non-reversing wheel dummy club or not to cause that whether the non-reversing wheel rotates the position or not to ascertain whether to unlatch the valve or not, such as the non-reversing wheel can rotate in reversing direction to unlatch the valve following the cam axle.

Description

Automatic pressure-reducing device

Technical field

The utility model relates to a kind of automatic pressure-reducing device of four-circulation motor, chamber pressure in the time of can suitably reducing engine start, thereby the operating load that turns round when alleviating engine start.

Technical background

At present; known decompression mechanism in engine is made up of one-way wheel and limiting stopper; this decompressor is to utilize motor when shutting down, the camshaft backward rotation, and rotation angle is generally less than 360 °; make and lean against the also rotation synchronously of the other one-way wheel of exhaust valve switch cam; at this moment in the other very little rise part that forms of exhaust valve switch cam basic circle, it is higher than cam base circle, and rocking arm is lifted by the fraction of this rise; exhaust valve is opened a little, suitably reduces chamber pressure.But during engine shutdown, the camshaft backward rotation is accidental, rather than camshaft all can backward rotation when under any circumstance shutting down at every turn, all can be the valve opening of firing chamber when so just not reaching each shutdown.

Summary of the invention

The purpose of this utility model is to release a kind of motor automatic pressure-reducing device; it can not only be when engine shutdown camshaft have under the counter-rotational situation and play decompression, and can also when shutting down, not have can play decompression under the counter-rotational situation by camshaft yet.

The purpose of this utility model is achieved in that automatic pressure-reducing device, is with one-way wheel near exhaust valve switch cam axle place on camshaft, and limiting stopper is installed on the engine body, and shift fork is installed on the limiting stopper.The end face of one-way wheel has the one-way wheel boss, and arc groove is arranged on the excircle.Be equipped with a hole on the camshaft, this hole and fixing pin one end are linked to be an integral body, and the fixing pin the other end is in a hole of centrifugal weight.One centrifugal spring is arranged between centrifugal weight and the camshaft, be enclosed within outside the fixing pin, the deviation of gravity center geometrical center of centrifugal weight on the centrifugal weight, has the centrifugal weight boss in relative one side with the one-way wheel boss.Return spring and limit spring are installed on the limiting stopper, all contact with shift fork.

The hole at described centrifugal weight center is oval, and centrifugal weight protrudes hole and the fixing pin sliding fit in the tooth.

The utility model has the advantages that: when motor normally moves work; automatic pressure-reducing device does not disturb any part; only when shutting down; no matter camshaft is just changeing or because of cylinder internal air pressure repulsion; make camshaft counter-rotating several angle; the utility model all can play decompression, because this decompression is to start function reliably to start.

Description of drawings

Fig. 1 is this automatic pressure-reducing device axial section along camshaft when being in decompression state;

Fig. 2 is the A-A sectional drawing of Fig. 1;

Fig. 3 is the B-B sectional drawing of Fig. 1;

The sectional drawing of automatic pressure-reducing device when Fig. 4 is the motor normal working.

Embodiment

Among the figure, 1. camshaft 1a. exhaust valve switch cam 1b. camshaft radial hole 2. one-way wheel 2a. one-way wheel boss 2b. one-way wheel shifting block 2c. one-way wheel arc grooves 3. rollers 4. springs 5. centrifugal weight 5a. centrifugal weight projection 5b. centrifugal weights protrude tooth 6. shift forks 7. limiting stoppers 8. rocking arms 9. return springs 10. connection rivets 11. front linings 12. fixing pins 13. centrifugal spring 14. valves 15. limit spring 16. back bushes 17. solid arrows 18. dotted arrows

Referring to Fig. 1, automatic pressure-reducing device has a circular one-way wheel 2, is enclosed within on the camshaft 1, leans against by the exhaust valve switch cam 1a.Rocking arm 8 can be pressed on one-way wheel 2 and the exhaust valve switch cam 1a simultaneously.Porose in the middle of the one-way wheel 2, three equally distributed curve baths are arranged on the inner circumference in hole, each curve bath is made up of the circular arc of two sections different radiis, a spring 4 and roller 3 are arranged in each curve bath, as shown in Figure 2, like this, when camshaft 1 is pressed the direction shown in the solid arrow 17 when rotating, one-way wheel 2 rotates together, and when camshaft 1 was pressed the rotation of 18 directions shown in the dotted arrow 18, one-way wheel 2 did not rotate.Arc groove 2c is arranged on the excircle of one-way wheel 2, and the Base radius of the center size of camshaft 1 less than exhaust valve switch cam 1a arrived in its bottom, and the radius of other remaining circumference is greater than Base radius 0.5-0.7mm.When this groove was under rocking arm 8, rocking arm 8 had been pressed on the basic circle of exhaust valve switch cam 1a, and when this position, exhaust valve switch cam 1a will be according to the profile energy normal switch valve of itself, and valve is not disturbed by one-way wheel.One-way wheel shifting block 2b is arranged on one-way wheel 2 excircles, and one-way wheel shifting block 2b can contact with shift fork 6, and can stir shift fork 6 and rotate.One end face of one-way wheel 2 has one-way wheel boss 2a, sees Fig. 1.The left side at one-way wheel 2, arrange that porose is centrifugal weight 5 oval, outer likeness in form " cucurbit ", have a centrifugal weight to protrude tooth 5b on centrifugal weight 5 cylindricals, it is the barycentric subdivision of centrifugal weight 5 that centrifugal weight protrudes tooth 5b right opposite, and centrifugal weight boss 5a is arranged on the end face of this part.In centrifugal weight protrusion tooth 5b a manhole is arranged, fixing pin 12 is arranged in the through hole, an end of fixing pin 12 and centrifugal weight protrude the hole sliding fit among the tooth 5b, and the other end is fixedlyed connected in aggregates with the hole of camshaft 1.Centrifugal weight 5 is to be connected with camshaft 1 by fixing pin 12, and centrifugal weight 5 can axially slide up and down along fixing pin 12.A centrifugal spring 13 is arranged between centrifugal weight 5 and the camshaft 1, be enclosed within outside the fixing pin 12.This centrifugal spring 13 can stretch up and down, and centrifugal weight 5 can be moved up and down on camshaft 1.Limiting stopper 7 is fixed on the engine body, and shift fork 6, front lining 11 and back bush 16 are fixed on the limiting stopper 7 by being connected rivet 10, and return spring 9 and limit spring 15 are enclosed within respectively outside front lining 11 and the back bush 16, contact with shift fork 6 respectively.Shift fork 6 can be respectively rotates before and after under the active force that is subjected to return spring 9 and one-way wheel shifting block 2b, and slewing area is by return spring 9 and limit spring 15 restrictions.In Fig. 4, the power that return spring 9 is turned right shift fork 6, limit spring 15 are then blocked shift fork 6 does not allow shift fork 6 turn right, and limit spring 15 power are greater than the power of return spring 9.

Now the automatic decompression process to present embodiment is described below:

When motor during in proper functioning, because fixing pin 12 effects are rotated centrifugal weight 5 and camshaft 1 synchronously, dotted arrow 18 directions of sense of rotation such as Fig. 2, the minimum speed of this rotation is enough to make centrifugal weight 5 to be departed from the centrifugal action of center of gravity, compress centrifugal spring 13, centrifugal weight 5 is offset on one side to the center, centrifugal weight boss 5a turning radius is greater than the radius of one-way wheel boss 2a like this, centrifugal weight boss 5a just can not contact with one-way wheel boss 2a so, return spring 9 and limit spring 15 make shift fork 6 be parked in the fixed position to one-way wheel 2, this position rocking arm 8 is in the arc groove 2c top of one-way wheel 2, as shown in Figure 4; rocking arm is pressed other positions less than one-way wheel 2, is not subjected to the interference of one-way wheel 2, thus exhaust valve switch cam 1a make the exhaust valve can correct switch according to this body contour of cam.

When motor in stopping process; the rotation rotating speed of camshaft 1 has two kinds of situations when slowing down gradually; first kind of situation is: be reduced to can not make centrifugal spring 13 overcome on the centrifugal force top centrifugal weight 5 time at the rotating speed of camshaft 1; the anti-push piston of the air pressure of firing chamber; thereby drive camshaft 1 counter-rotating, promptly rotate as solid arrow 17 directions of Fig. 2.At this moment one-way wheel 2 is owing to rotated with camshaft 1 by spring 4 and roller 3 effects, the arc groove 2c of one-way wheel 2 has just rotated an angle so, the other very little rise part that forms of exhaust valve switch cam 1a basic circle, it is higher than cam base circle 0.5-0.7mm; the fraction that rocking arm 8 is this time risen lifts; exhaust valve is opened a little, has suitably reduced chamber pressure, alleviates crank rotation load for starting next time.

Second kind of situation is: the rotating speed of camshaft 1 is reduced to and can makes centrifugal spring 13 overcome centrifugal action to be got in centrifugal weight 5 top.At this moment the turning radius of centrifugal weight boss 5a is suitable with one-way wheel boss 2a radius, with camshaft 1 rotation, centrifugal weight boss 5a just promotes one-way wheel boss 2a, thereby driving one-way wheel 2 rotates, the arc groove 2 of one-way wheel 2 has just rotated an angle so, the other very little rise part that forms of exhaust valve switch cam 1a basic circle, it is higher than cam base circle 0.5-0.7mm; the fraction that rocking arm 8 is this time risen lifts; exhaust valve is opened a little; suitably reduced chamber pressure, alleviates crank rotation load for starting next time.

Claims

1, automatic pressure-reducing device, on camshaft, be with one-way wheel, limiting stopper is installed on the engine body, shift fork is installed on the limiting stopper near exhaust valve switch cam axle place, it is characterized in that: the end face of one-way wheel has the one-way wheel boss, and arc groove is arranged on the excircle; Be equipped with a hole on the camshaft, this hole and fixing pin one end are linked to be an integral body, and the fixing pin the other end is in a hole of centrifugal weight; One centrifugal spring is arranged between centrifugal weight and the camshaft, and centrifugal spring housing is outside fixing pin, and the deviation of gravity center geometrical center of centrifugal weight on the centrifugal weight, has the centrifugal weight boss in relative one side with the one-way wheel boss; Return spring and limit spring are installed on the limiting stopper, all contact with shift fork.

2, automatic pressure-reducing device according to claim 1, the hole that it is characterized in that the centrifugal weight center is for oval, and centrifugal weight protrudes hole and the fixing pin sliding fit in the tooth.