CN1460147A

CN1460147A - Decompressor for 4-stroke cycle IC engine

Info

Publication number: CN1460147A
Application number: CN02800967A
Authority: CN
Inventors: 阿久津敏治; 泽村吉信; 早田雄一; 小林英男; 坂本文一郎
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 2001-03-30
Filing date: 2002-02-22
Publication date: 2003-12-03
Anticipated expiration: 2022-02-22
Also published as: WO2002081877A1; CN1267624C; BR0204748B1; TR200202591T1; AR033078A1; BR0204748A; MY141810A

Abstract

In a 4-stroke cycle internal combustion engine equipped with a suction valve (13) and an exhaust valve (14) which are driven for opening and closing by a suction cam (17) and an exhaust cam (18), respectively, which are integral with a cam shaft (19), a decompressor cam (35) is fitted on the cam shaft (19) through a one-way clutch (34) capable of transmitting torque only during reverse rotation and in such a manner as to be adjacent to at least one of the suction and exhaust cams (17, 18). Further, cam rollers (32) respectively rolling in contact with the suction and exhaust cams (17, 18) are respectively rotatably pivoted on the ends of rocker arms (26, 27) for opening the suction and exhaust valves ( 13, 14), and decompressor cam abutments (33) for the rocker arms (26, 27), which abut against the decompressor cam (35), are formed on the ends of the rocker arms (26, 27) which support cam rollers (32). Thereby, it is possible to reduce the dimension in the direction of the axis of rotation of the cam rollers (32) to reduce the width of the rocker arms (26, 27); thus, it becomes possible to reduce the power for driving the valve-moving device, and to reduce the size of the decompressor. A stop piece (41) slidably installed to pass through a through-hole (40a) in a stop piece support portion (40) disposed on a cylinder head (3) makes it possible to lock the locking projection (39a) on the peripheral edge of the decompressor cam (35).

Description

The decompressor of 4 stroke IC engines

Technical field

The present invention relates to a kind of decompressor that helps the starting of 4 stroke IC engines by starter motor.

Background technique

As everyone knows, its mechanical type decompressor of 4 stroke IC engines be provided with and the adjacent relief cam of one of the air inlet cam of integrated camshaft and exhaust cam, when starting, make rocker arms roll by relief cam, and can't help air inlet cam or exhaust cam and open Aspirating valves or outlet valve, but help bent axle to quicken rotation by starter motor.Relief cam by only have when camshaft reverses could transmitting torque overrunning clutch be bearing on the camshaft.

4 stroke IC engines like this, when this internal-combustion engine stops, rotatory inertia by internal-combustion engine rotation system continued the bent axle of rotation before the upper dead center of compression stroke, when when after temporarily shutting down, reversing because the pressure of firing chamber raises, the overrunning clutch that is contained between camshaft and the relief cam that is situated between becomes coupled condition, relief cam also reverses with camshaft, open any one of Aspirating valves, outlet valve by the nose of cam of relief cam, therefore, can alleviate the positive torque of the bent axle that drives by starter motor, help engine starting.

The nose of cam set positions of the relief cam the when decompressor that has shuts down 4 stroke IC engines is in the position of regulation, therefore, on this relief cam, dashed forward in the past and established snap-latch piece, on cylinder cap, form simultaneously blind hole, setting-in helical spring and block (opening flat 5-86824 number) successively in this blind hole with reference to the Japanese patent gazette spy towards this snap-latch piece.

But above-mentioned mechanical decompressor in order to contact with air inlet cam or exhaust cam, also contacts the roller of pivot suspension on rocking arm with relief cam.Therefore, it is big that the width of rocking arm becomes, and the inertial mass of rocking arm has increased, and is difficult to reduce the volume of whole valve device.

On the other hand, 4 stroke IC engines of above-mentioned band decompressor, though parts such as cylinder head cover are dismounting freely in the opening extension side of above-mentioned blind hole, but at cylinder cap and cylinder head cover is the occasion of one, above-mentioned block is installed on the cylinder cap rather bothers, in addition, maintenance needs labour and time.

The objective of the invention is to obtain a kind of decompressor that has overcome 4 stroke IC engines of above-mentioned shortcoming.

Summary of the invention

In order to achieve the above object, Aspirating valves and outlet valve that the decompressor of 4 stroke IC engines that a kind of form according to the present invention provides possesses camshaft and drives its switching respectively by air inlet cam and exhaust cam with this integrated camshaft also have the starter motor that is used to start; Relief cam by only could transmitting torque when the counter-rotating of above-mentioned camshaft overrunning clutch and at least one adjacent ground connection of above-mentioned air inlet cam and exhaust cam be inlaid on the above-mentioned camshaft, be provided with when above-mentioned relief cam moves, be associated with this relief cam and make above-mentioned Aspirating valves and outlet valve at least one be in out the threshold switch driver part of valve state, it is characterized in that: contact with at least one of above-mentioned air inlet cam and exhaust cam and the cam rollers of rotating can be freely rotationally pivot suspension on the cam rollers support of above-mentioned threshold switch driver part, above-mentioned cam rollers has the axial dimension that does not contact with above-mentioned relief cam, is provided with the contacting part that only contacts with above-mentioned relief cam on the cam rollers support of above-mentioned threshold switch driver part.

Constitute decompressor owing to resemble above-mentioned, the cam rollers of pivot suspension on the threshold switch driver part only contacts just enough with air inlet cam or exhaust cam, therefore, the length of cam rollers is short, the result has been the narrowed width of threshold switch driver part, the inertial mass of threshold switch driver part has diminished, avoided making Aspirating valves or outlet valve to have increase all the time to the spring load of the valve spring of the trend of the direction motion of closing valve, reduced the power that is used to drive valve device, and, can reduce the volume of valve device.

In order to achieve the above object, the decompressor of 4 stroke IC engines that another form according to the present invention provides, the Aspirating valves and the outlet valve that possess camshaft and drive its switching respectively by air inlet cam and exhaust cam with this integrated camshaft also have the starter motor that is used to start; Relief cam by only could transmitting torque when camshaft reverses overrunning clutch and at least one adjacent ground connection of air inlet cam and exhaust cam be inlaid on the above-mentioned camshaft; Be provided with when relief cam moves, be associated with this relief cam and make Aspirating valves and outlet valve at least one be in out the threshold switch driver part of valve state, it is characterized in that: the periphery at above-mentioned relief cam is provided with the engaging teat, this engaging teat forms the plane of inclination with it becomes reverse directions the place ahead when above-mentioned relief cam reverses a side, this plane of inclination tilts lentamente from the base portion forward end, setting is stretched out it by the spring towards the engaging teat of above-mentioned relief cam and is stuck in catch on this engaging teat, this catch connects towards relief cam slidably, is arranged on the cylinder cap of internal-combustion engine, the through hole of the catch support on cylinder head cover or the camshaft holder.

Constitute decompressor owing to resemble above-mentioned, so, even not as in the past decompressor, catch is inlaid in towards the blind hole of the piston glide direction from cylinder cap towards relief cam, if can be at the cylinder cap that should be provided with on the locational catch extending direction of catch, the catch support of the through hole that possesses the chimeric catch of energy is set on cylinder head cover or the camshaft holder, then also can have no relation ground with whether cylinder head cover and catch direction are arranged, be arranged on the catch that under the normal operating condition relief cam is remained on predetermined angular at an easy rate, can make simple in structure, and can reduce the component number, can increase substantially assembling performance and maintenance, and be convenient to reduce cost.

Description of drawings

Fig. 1 is the side view of single cylinder OHC4 stroke IC engine that possesses the present invention the 1st embodiment's decompressor.

Fig. 2 is the longitudinal section at the main position of this internal-combustion engine.

Fig. 3 is the sectional view of cylinder cap portion of this embodiment's of expression decompressor.

Fig. 4 is the effect schematic representation of this embodiment's decompressor.

Fig. 5 is the effect schematic representation of this embodiment's decompressor.

Fig. 6 is the effect schematic representation of this embodiment's decompressor.

Fig. 7 is the effect schematic representation of this embodiment's decompressor.

Fig. 8 is this embodiment's the relief cam and the amplification view of catch.

Fig. 9 is the side view of this embodiment's exhaust rocker arm.

Figure 10 is the plan view of this embodiment's exhaust rocker arm.

Figure 11 is the XI-XI line side cross sectional view along Fig. 9.

Figure 12 is the axial configuration schematic diagram of cam of the decompressor of the foregoing description.

Figure 13 is the axial configuration schematic diagram of cam of the present invention the 2nd embodiment's decompressor.

Figure 14 is near the sectional view of outlet valve of this embodiment's of expression decompressor.

Figure 15 is the effect schematic representation of this embodiment's decompressor.

Figure 16 is the effect schematic representation of this embodiment's decompressor.

Figure 17 is the effect schematic representation of this embodiment's decompressor.

Figure 18 is the effect schematic representation of this embodiment's decompressor.

Figure 19 is the axial configuration schematic diagram of cam of the present invention the 3rd embodiment's decompressor.

Figure 20 is near the sectional view of outlet valve of this embodiment's of expression decompressor.

Figure 21 is the effect schematic representation of this embodiment's decompressor.

Figure 22 is the effect schematic representation of this embodiment's decompressor.

Figure 23 is the effect schematic representation of this embodiment's decompressor.

Figure 24 is the effect schematic representation of this embodiment's decompressor.

Embodiment

Below Fig. 1 is described to the 1st embodiment of the present invention shown in Figure 12.

Lift-launch is on the motorcycle that do not show of figure and possess the body of the single cylinder OHC4 stroke IC engine O of decompressor of the present invention, as depicted in figs. 1 and 2, by constituting with the bottom: cylinder-bore 4 is the cylinder body 1 of directed forward (in Fig. 1 for right-hand, in Fig. 2 be above) substantially horizontal roughly; Be configured in the crankcase 2 of the rear end of this cylinder body 1; Be configured in the cylinder cap 3 of the front end of above-mentioned cylinder body 1, on above-mentioned cylinder body 1, be formed with cylinder-bore 4, cylinder body 1, crankcase 2 and cylinder cap 3 are linked into an integrated entity by connect the bolt that cylinder cap 3 and cylinder body 1 screw on crankcase 2 from car body the place ahead.

In addition, as shown in Figure 2, in the cylinder-bore 4 of above-mentioned cylinder body 1, be embedded with the piston 5 that can slide freely, point to the overall width direction and can be freely rotationally the bent axle 6 of pivot suspension on crankcase 2 be connected by connecting rod 7 with piston 5, the interlock that moves back and forth of bent axle 6 and piston 5 drives it and rotates to clockwise direction in Fig. 1.

In addition, on crankcase 2 with bent axle 6 abreast pivot suspension the main shaft 8 and the countershaft 9 that can rotate freely arranged, countershaft 9 is projected into the outside from crankcase 2, ring chain (figure does not show) hangs over the end design all-in-one-piece with countershaft 9, on the driven sprocket (figure does not show) of the driving sprocket wheel that do not show of figure and the trailing wheel one do not shown with figure, on above-mentioned bent axle 6 and main shaft 8, be provided with clutch, and, on main shaft 8 and countershaft 9, be provided with the gear that figure does not show, bent axle 6 with the state that is higher than rotation of certain rotating speed and clutch and is connecting under, by meshing the gear of above-mentioned main shaft 8 and countershaft 9 selectively, the just rear wheel rotation that can not show with the gear ratio driving figure of regulation.

Have again, extremely shown in Figure 7 as Fig. 3, on cylinder cap 3, be formed with the air intake passage 11 and the exhaust passage 12 that are communicated with the firing chamber 10 on cylinder-bore 4 tops, be arranged on Aspirating valves 13 on this air intake passage 11 and the outlet valve 14 that is arranged on the exhaust passage 12 and be configured to the V font, and be designed to and open and close freely, positioning work piece 15 is installed in the top of this Aspirating valves 13 and outlet valve 14 integratedly, and the elastic force that is contained in the valve spring 16 between positioning work piece 15 and the cylinder cap 3 by Jie makes above-mentioned Aspirating valves 13 and outlet valve 14 that the pent trend of wanting be arranged all the time.And, be equipped with throttle valve, vaporizer and the filter cleaner that towards the upstream one side and figure do not show in the upstream of air intake passage 11 side.

In addition, as shown in Figure 3, the central authorities at the superjacent air space of Aspirating valves 13 and outlet valve 14 are provided with camshaft 19.As shown in Figure 2, this camshaft 19 possesses air inlet cam 17 and exhaust cam 18 integratedly, by pair of bearings 20 can be freely rotationally pivot suspension on cylinder cap 3.Driven sprocket 22 is installed in an end of this camshaft 19 integratedly by many bolts 21, and ring chain 24 hangs on the driving sprocket wheel 23 and above-mentioned driven sprocket 22 with bent axle 6 one, and drive cam shaft 19 is with 1/2 rotation of bent axle 6 rotating speeds.

Have again, extremely shown in Figure 7 as Fig. 3, have at cylinder cap 3 upper supports each top that lays respectively at above-mentioned Aspirating valves 13 and outlet valve 14 and camshaft 19 intermediate portion above and the 1 pair pitman arm shaft 25 parallel with camshaft 19, be supported with the air-breathing rocking arm 26 and the exhaust rocker arm 27 that can shake freely respectively at these pitman arm shaft 25 head lamp brush guard pivots, end at this air-breathing rocking arm 26 and exhaust rocker arm 27 screws in tappet screw 28, and being fixed by locking nut 29 is integral.In addition, to shown in Figure 11, on the roller supporting axle 30 on the two forked end 27a of the other end that is inlaid in air-breathing rocking arm 26 and exhaust rocker arm 27, the cam rollers 32 that can rotate is freely arranged as Fig. 9 by needle bearing 31 pivot suspensions.

Have again, below the end of the medial and lateral of two forked end 27a of the other end of above-mentioned exhaust rocker arm 27 (in Fig. 9～Figure 11), be formed with the relief cam contacting part 33 that can contact with the outer circumferential face 36 of relief cam 35 described later.As shown in Figure 9, this relief cam contacting part 33 is made from portion's sheet of the side of two forked end 27a of air-breathing rocking arm 26 and exhaust rocker arm 27 to the outstanding form of relief cam 35.

And, as Fig. 2 and shown in Figure 12, relief cam 35 is adjacent with the end 27a in the outside of above-mentioned exhaust rocker arm 27, be inlaid on the camshaft 19 by overrunning clutch 34, in Fig. 3 to Fig. 7, make it just change the occasion of (to the rotation of arrow N direction) to clockwise direction at camshaft 19, the clockwise moment of torsion of camshaft 19 can be delivered to relief cam 35 hardly, in the occasion of camshaft 19 to counter-rotating counterclockwise (to the rotation of arrow R direction), the anticlockwise moment of torsion of camshaft 19 can be delivered to relief cam 35.

In addition, as shown in Figure 8, on the outer circumferential face 36 of relief cam 35, be formed with: notch part 37; Be positioned at the nose of cam 38 of clockwise direction one side of notch part 37; Under relief cam contacting part 33 state of contact of this notch part 37 and exhaust rocker arm 27, can be stuck in the engaging teat 39 on the catch 41 described later.

Have again, in Fig. 3 to Fig. 8, (car body top) is formed with catch support 40 to camshaft 19 from the left side on cylinder cap 3, in the through hole 40a of this catch support 40, be embedded with the catch 41 that can engage slidably with the minor diameter of its front end to camshaft 19, simultaneously, can be embedded with the helical spring 42 (Fig. 8) that is connected with the rear end of catch 41 loosely, and be combined with the bolt 43 that is connected with the rear end of above-mentioned helical spring 42 at the base end part of catch support 40.In the occasion of relief cam 35 to positive veer N (clockwise direction) rotation, engaging teat 39 is stuck on the catch 41, in addition, the occasion that contacts with catch 41 to the plane of inclination 39a of reverse directions R (counterclockwise) rotation, engaging teat 39 at relief cam 35, the plane of inclination 39a that catch 41 is stuck teat 39 flexibly is pressed into the inboard, the engaging teat 39 of relief cam 35 can't be blocked by catch 41, and can cross catch 41.

Fig. 1 is to embodiment shown in Figure 12 constitute above-mentioned owing to resemble, so, under normal operating condition, when internal-combustion engine 0 shuts down, before the upper dead center of compression stroke, bent axle 6 since the pressure risings in the firing chamber 10 stop operating.The air inlet cam 17 of the camshaft 19 of this moment and exhaust cam 18 and relief cam 35 are in position shown in Figure 3.

And, after bent axle 6 temporarily stops, bent axle 6 is because very high pressure in the firing chamber 10 and to counterclockwise only reversing small angle, if therefore camshaft 19 also stops operating after the counter-rotating, then as shown in Figure 4, to the overrunning clutch 34 of reverse directions transmitting torque, relief cam 35 also reverses and stops operating after the identical angle by only.At this moment, relief cam contacting part 33 backstops of exhaust rocker arm 27 are on the nose of cam 38 of relief cam 35, and exhaust rocker arm 27 shakes to clockwise direction, even compression stroke outlet valve 14 also can be opened.Under the state that shuts down shown in Figure 4, if camshaft 19 just changes to clockwise direction linkedly with the bent axle 6 of the starter motor rotary driving of being schemed not show, then as shown in Figure 5, though exhaust cam 18 is near the cam rollers 32 of exhaust rocker arm 27, but during this period, because the relief cam contacting part 33 of exhaust rocker arm 27 contacts with the nose of cam 38 of relief cam 35, effect has frictional force on relief cam 35, and, overrunning clutch 34 is not delivered to relief cam 35 with the natural rotating force square, so relief cam 35 is irrelevant with the just commentaries on classics of camshaft 19 and exhaust cam 18, and stops operating.

Under state shown in Figure 5, if camshaft 19 further just changes, become state shown in Figure 6, then cam rollers 32 backstops of exhaust rocker arm 27 are at the nose of cam of exhaust cam 18, the relief cam contacting part 33 of exhaust rocker arm 27 leaves the nose of cam 38 of relief cam 35, so, relief cam 35 becomes the state that does not retrain fully, relief cam 35 rotates to clockwise direction with camshaft 19 synchronously owing to the very little moment of torsion that just changes transmission of overrunning clutch 34, the engaging teat 39 of relief cam 35 contacts and is blocked by catch 41, and relief cam 35 stops at this position.

And, if camshaft 19 and exhaust cam 18 further just change, as shown in Figure 7, when the nose of cam of exhaust cam 18 leaves the cam rollers 32 of exhaust rocker arm 27, then the relief cam contacting part 33 of exhaust rocker arm 27 drops into the notch part 37 of relief cam 35, remove the pressure-reducing function of relief cam 35, therefore, single cylinder OHC4 stroke IC engine 0 is transformed into normal operating condition.

So, since from the upper dead center of compression stroke via expansion stroke, exhaust stroke until before suction stroke finishes, firing chamber 10 is communicated with atmosphere, so, the just commentaries on classics resistance of having got rid of the single cylinder OHC4 stroke IC engine 0 that produces owing to the rising of the pressure in the firing chamber 10, the just commentaries on classics of bent axle 6 can steadily and fully be quickened, and single cylinder OHC4 stroke IC engine 0 can start reliably.

In addition, because pivot suspension with on the outer circumferential face 36 of relief cam 35 does not contact in the cam rollers on the end of exhaust rocker arm 27 32, but the relief cam contacting part 33 of two forked end 27a that supports the exhaust rocker arm 27 of this cam rollers 32 contacts with the outer circumferential face 36 of relief cam 35, so, cam rollers 32 is not long in its running shaft direction, therefore, can reduce the width of exhaust rocker arm 27, consequently, can do exhaust rocker arm 27 less, and can make whole valve device very compact, can make single cylinder OHC4 stroke IC engine 0 volume little in light weight.

Below, Figure 13 is described to the 2nd embodiment of the present invention shown in Figure 180.This embodiment is the example that decompressor of the present invention is applied to the single cylinder DOHC4 stroke IC engine of swing-arm type, and relief cam and exhaust cam are in abutting connection with setting.

As shown in figure 14, exhaust swing arm 50 is rotatably supported in its base end part on the arm shaft 51, and the lower end that is installed in the tappet screw 28 of its front end by locking nut 29 contacts with the upper end of the axle portion 14a of outlet valve 14.Outlet valve 14 has the trend of moving to the direction of closing valve owing to the valve spring 16 between the spring seat that is installed in positioning work piece 15 and cylinder cap 3 one sides.

As Figure 13 and shown in Figure 14, at the central part 50a of exhaust swing arm 50, cam rollers 32 can be bearing on the roller supporting axle 30 freely rotatably by needle bearing 31.Above the above-mentioned cam rollers 32 of exhaust swing arm 50, be provided with the ring chain that do not show with figure by the camshaft 19 of crank-driven with 1/2 rotating speed rotation of bent axle, on this camshaft 19, be provided with the exhaust cam 18 that becomes one and rotate with it.What draw among Figure 13 is the nose of cam 18a and cam rollers 32 state of contact of this exhaust cam.Camshaft 19 remains on the camshaft holder 44 that is made of top jaw axle bed 44U and lower cam axle bed 44L.They are covered with by cylinder head cover 45.

As shown in figure 13, on camshaft 19, be embedded with exhaust cam 18 in abutting connection with and possess the relief cam 35 of overrunning clutch 34.In Figure 14 to Figure 18, just change the occasion of (to the rotation of arrow N direction) to clockwise direction at camshaft 19, the clockwise moment of torsion of camshaft 19 can be delivered to relief cam 35 hardly, in the occasion of camshaft 19 to counter-rotating counterclockwise (to the rotation of arrow R direction), the anticlockwise moment of torsion of camshaft 19 can be delivered to relief cam 35.

As shown in figure 14, on the outer circumferential face 36 of relief cam 35, be formed with notch part 37 and the nose of cam 38 that is positioned at clockwise direction one side of this notch part 37.On the central part 50a of above-mentioned exhaust swing arm 50 side, be formed with the relief cam contacting part 33 that can contact with the outer circumferential face 36 of above-mentioned relief cam 35.

On the top jaw axle bed 44U above the camshaft, be formed with catch support 40 towards camshaft 19, the catch 41 that the helical spring 42 that is connected with bolt 43 with the rear end pushes from the rear be installed slidably in the front end minor diameter of the through hole 40a of this catch support 40.In addition, on the outer circumferential face 36 of relief cam 35, on the position of staggering with above-mentioned nose of cam 38, be formed with the engaging teat 39 that contacts with above-mentioned catch 41 in the axial direction.On relief cam outer circumferential face 36, engaging teat 39 is arranged on when the relief cam contacting part 33 of exhaust swing arm 50 contacts with the notch part 37 of relief cam 35 and catch 41 position contacting.

In Figure 14 to Figure 18, in the occasion of relief cam 35 to positive veer (N direction) rotation, the engaging teat 39 of relief cam 35 is stuck on the catch 41, in addition, in the occasion of relief cam 35 to reverse directions (R direction) rotation, the plane of inclination 39a that catch 41 is stuck teat 39 is flexibly pressed to the inboard, and relief cam 35 can not be blocked by catch 41.

Because resembling, the 2nd embodiment constitutes above-mentioned, so, running well (just change, to the rotation of N direction) afterwards, if engine stops, then before the upper dead center of compression stroke, bent axle stops operating, and the exhaust cam 18 of this moment and the position of relief cam 35 are shown in Figure 14.That is, the engaging teat 39 of relief cam 35 is blocked by catch 41, and the relief cam contacting part 33 of exhaust swing arm 50 is in the position in the notch part 37 that drops into relief cam 35.

And after bent axle 6 temporarily stopped, if because the very high pressure in the firing chamber and to (R direction) counter-rotating counterclockwise, then owing to the engagement of overrunning clutch 34, the relief cam 35 identical angle of also reversing stopped at position shown in Figure 15.That is, nose of cam 38 backstops of relief cam 35 are on the relief cam contacting part 33 of exhaust swing arm 50, and exhaust swing arm 50 is rotated some angles to clockwise direction, even become also can be opened any state of compression stroke outlet valve 14.This is the state when shutting down.

Under the state that shuts down of Figure 15, if this internal-combustion engine started, the bent axle interlock of camshaft 19 and the starter motor rotary driving of being schemed not show just changes (N direction) to clockwise direction, then as shown in figure 16, exhaust cam 18 is near the cam rollers 32 of exhaust swing arm 50.At this moment, because nose of cam 38 backstops of relief cam 35 at the relief cam contacting part 33 of exhaust swing arm 50, have frictional force so act on, and, because the rotation of camshaft 19 is just to change (N direction), so overrunning clutch 34 is in the state that connects of removing.Therefore, even camshaft 19 and exhaust cam 18 rotations, relief cam 35 also is in the state that temporarily stops.

State from Figure 16, camshaft 19 further just changes, as shown in figure 17, when the state of cam rollers 32 backstops that become exhaust swing arm 50 at the nose of cam 18a of exhaust cam 18, because the nose of cam 38 of relief cam 35 leaves the relief cam contacting part 33 of exhaust swing arm 50, so, the frictional force of effect has also disappeared, relief cam 35 becomes unconfined state, rotate synchronously to clockwise direction with camshaft 19 by the very little just commentaries on classics transmitting torque of overrunning clutch 34, when blocking in engaging teat 39 contacts of relief cam 35 and by catch 41, relief cam 35 stops at this position.Sometimes camshaft 19 also can occur is just changeing several circles, in relief cam 35 jammed phenomenon after small angle ground synchronously rotates several circles thereupon.

Camshaft 19 and exhaust cam 18 continue just to change, as shown in figure 18, if relief cam 35 is blocked by catch 41, the nose of cam 18a of exhaust cam 18 leaves cam rollers 32, then the relief cam contacting part 33 of exhaust swing arm 50 drops into the notch part 37 of relief cam 35, removed the pressure-reducing function of relief cam 35, therefore, internal-combustion engine is transformed into normal operating condition after this.

As previously discussed, because the cam rollers 32 of pivot suspension on the central part 50a of exhaust swing arm 50 do not contact with the outer circumferential face 36 of relief cam 35, the relief cam contacting part 33 that supports above central part one side of exhaust swing arm 50 of this cam rollers 32 contacts with the outer circumferential face 36 of relief cam 35, so, cam rollers 32 is not long on its supporting axle 30 directions, therefore, can reduce the width of exhaust swing arm 50, consequently, can do exhaust swing arm 50 less, and can make whole valve device very compact, can make single cylinder DOHC4 stroke IC engine volume little in light weight.

Below Figure 19 is described to the 3rd embodiment of the present invention shown in Figure 24.This embodiment is the example that decompressor of the present invention is applied to single DOHC4 stroke IC engine of straight flowing mode.Relief cam and exhaust cam are in abutting connection with setting.

As shown in figure 20, the body of exhaust valve lifter 60 constitutes by cylindrical part 61 with the roller support 62 of these cylindrical part 61 one, and the position in the upper end portion of the axostylus axostyle 14a that covers outlet valve 14 can be maintained slidingly retained on the cylinder cap 3 on the direction of this axostylus axostyle 14a.The central authorities of roller support 62 contact below by the upper end of pad 63 with axostylus axostyle 14a.Above-mentioned outlet valve 14 has the trend of moving to the direction of closing valve owing to the valve spring 16 between the spring seat that is installed in positioning work piece 15 and cylinder cap 3 one sides.

As Figure 19 and shown in Figure 20, in the central upper of exhaust valve lifter 60, cam rollers 32 can be bearing on the roller supporting axle 30 freely rotatably by needle bearing 31.Above the above-mentioned cam rollers 32 of exhaust valve lifter 60, be provided with the ring chain that do not show with figure by the camshaft 19 of crank-driven with 1/2 rotating speed rotation of bent axle, on this camshaft 19, be provided with the exhaust cam 18 that becomes one and rotate with it.What draw among Figure 19 is the nose of cam 18a and cam rollers 32 state of contact of this exhaust cam.Camshaft 19 remains on the camshaft holder 44 that is made of top jaw axle bed 44U and lower cam axle bed 44L.They are covered with by cylinder head cover 45.

As shown in figure 19, on camshaft 19, be embedded with exhaust cam 18 in abutting connection with and possess the relief cam 35 of overrunning clutch 34.In Figure 20 to Figure 24, just change the occasion of (to the rotation of arrow N direction) to clockwise direction at camshaft 19, the clockwise moment of torsion of camshaft 19 can be delivered to relief cam 35 hardly, in the occasion of camshaft 19 to counter-rotating counterclockwise (to the rotation of arrow R direction), the anticlockwise moment of torsion of camshaft 19 can be delivered to relief cam 35.

As shown in figure 20, on the outer circumferential face 36 of relief cam 35, be formed with notch part 37 and the nose of cam 38 that is positioned at clockwise direction one side of this notch part 37.On a side of the roller support 62 of above-mentioned exhaust valve lifter 60, be formed with the relief cam contacting part 33 that can contact with the outer circumferential face 36 of above-mentioned relief cam 35.

In Figure 20, on the lower cam axle bed 44L of camshaft left, be formed with catch support 40 towards camshaft 19, catch 41 that the helical spring 42 that is connected with bolt 43 with the rear end pushes from the rear is installed slidably in addition in the front end minor diameter of the through hole 40a of this catch support 40, on the outer circumferential face 36 of relief cam 35, on the position of staggering with above-mentioned nose of cam 38, be formed with the engaging teat 39 that contacts with above-mentioned catch 41 in the axial direction.On relief cam outer circumferential face 36, engaging teat 39 is arranged on when the relief cam contacting part 33 of exhaust valve lifter 60 contacts with the notch part 37 of relief cam 35 and catch 41 position contacting.And, though catch 41 is arranged on the left side (Figure 20) of relief cam 35,, in Figure 19, they are drawn in the top of relief cam 35 in order to represent the axial position of catch 41 and engaging teat 39.

In Figure 20 to Figure 24, in the occasion of relief cam 35 to positive veer (N direction) rotation, the engaging teat 39 of relief cam 35 is blocked by catch 41, in addition, in the occasion of relief cam 35 to reverse directions (R direction) rotation, the plane of inclination 39a that catch 41 is stuck teat 39 flexibly is pressed into the inboard, and relief cam 35 can not be blocked by catch 41.

Because resembling, the 3rd embodiment constitutes above-mentioned, so, running well (just change, to the rotation of N direction) afterwards, if engine stops, then before the upper dead center of compression stroke, bent axle stops operating, and the exhaust cam 18 of this moment and the position of relief cam 35 are shown in Figure 20.That is, the engaging teat 39 of relief cam 35 is blocked by catch 41, and the relief cam contacting part 33 of exhaust valve lifter 60 is in the position in the notch part 37 that drops into relief cam 35.

And after bent axle temporarily stopped operating, if because the very high pressure in the firing chamber and to (R direction) counter-rotating counterclockwise, then owing to the engagement of overrunning clutch 34, the relief cam 35 identical angle of also reversing stopped at position shown in Figure 21.That is, nose of cam 38 backstops of relief cam 35 are on the relief cam contacting part 33 of exhaust valve lifter 60, and exhaust valve lifter 60 rotates some angles to clockwise direction, even become also can be opened any state of compression stroke outlet valve 14.This is the state when shutting down.

Under the state that shuts down of Figure 21, if this internal-combustion engine started, the bent axle interlock of camshaft 19 and the starter motor rotary driving of being schemed not show just changes (N direction) to clockwise direction, then as shown in figure 22, exhaust cam 18 is near the cam rollers 32 of exhaust valve lifter 60.At this moment, because nose of cam 38 backstops of relief cam 35 are at the relief cam contacting part 33 of exhaust valve lifter 60, so effect has frictional force.And, because the rotation of camshaft 19 is just to change (N direction), so overrunning clutch 34 is in the state that connects of removing.Therefore, even camshaft 19 and exhaust cam 18 rotations, relief cam 35 also is in the state that temporarily stops.

From the state of Figure 22, camshaft 19 further just changes, and as shown in figure 23, on the nose of cam 18a of cam rollers 32 backstops at exhaust cam 18 of exhaust valve lifter 60 time, it is bigger that outlet valve 14 is opened.When becoming this state, because the nose of cam 38 of relief cam 35 leaves the relief cam contacting part 33 of exhaust valve lifter 60, so, the frictional force of effect has also disappeared, relief cam 35 becomes unconfined state, rotates synchronously to clockwise direction with camshaft 19 by the very little just commentaries on classics transmitting torque of overrunning clutch 34.When blocking in engaging teat 39 contacts of relief cam 35 and by catch 41, relief cam 35 stops at this position.Usually camshaft 19 is just changeing several circles, is stuck after rotating several circles synchronously on small angle ground at relief cam 35 thereupon.

Camshaft 19 and exhaust cam 18 continue just to change, as shown in figure 24, if relief cam 35 is blocked by catch 41, the nose of cam 18a of exhaust cam 18 leaves cam rollers 32, then the relief cam contacting part 33 of exhaust valve lifter 60 drops into the notch part 37 of relief cam 35, removed the pressure-reducing function of relief cam 35, therefore, internal-combustion engine is transformed into normal operating condition after this.

As previously discussed, because the cam rollers 32 of pivot suspension on the roller support 62 of exhaust valve lifter 60 do not contact with the outer circumferential face 36 of relief cam 35, the relief cam contacting part 33 that supports above roller support 62 1 sides of exhaust valve lifter 60 of this cam rollers 32 contacts with the outer circumferential face 36 of relief cam 35, so, cam rollers 32 is not long on its supporting axle 30 directions, therefore, can reduce roller support 62 width of exhaust valve lifter 60, consequently, can do exhaust valve lifter 60 less, can make whole valve device very compact, can make single cylinder DOHC4 stroke IC engine volume little in light weight.

Though more than the decompressor that valve-opening mechanism constituted by outlet valve is illustrated,, also can use principle same as described above to Aspirating valves and constitute decompressor.

Claims

1. the decompressor of a stroke IC engine, the Aspirating valves (1 3) and the outlet valve (14) that possess camshaft (19) and drive its switching respectively by air inlet cam (17) and exhaust cam (18) with this camshaft (19) one also have the starter motor that is used to start; The overrunning clutch (34) of relief cam (35) by only could transmitting torque when above-mentioned camshaft (19) reverses is inlaid on the above-mentioned camshaft (19) with at least one adjacent ground connection of above-mentioned air inlet cam (17) and exhaust cam (18); Be provided with when above-mentioned relief cam (35) moves, be associated with this relief cam (35) and make above-mentioned Aspirating valves (13) and outlet valve (14) at least one be in out the threshold switch driver part (26,27,50,60) of valve state, it is characterized in that:

The cam rollers (32) that contacts with at least one of above-mentioned air inlet cam (17) and exhaust cam (18) and rotate can be freely rotationally pivot suspension on the cam rollers support (27a, 50a, 62) of above-mentioned threshold switch driver part (26,27,50,60), above-mentioned cam rollers (32) has the axial dimension that does not contact with above-mentioned relief cam (35), is provided with the relief cam contacting part (33) that only contacts with above-mentioned relief cam (35) on the cam rollers support (27a, 50a, 62) of above-mentioned threshold switch driver part (26,27,50,60).

2. according to the decompressor of rocking arm type 4 stroke IC engines of claim 1, it is characterized in that: above-mentioned threshold switch driver part (26,27,50,60) is rocking arm (26,27).

3. according to the decompressor of swing-arm type 4 stroke IC engines of claim 1, it is characterized in that: above-mentioned threshold switch driver part (26,27,50,60) is swing arm (50).

4. according to the decompressor of direct valve drive-type 4 stroke IC engines of claim 1, it is characterized in that: above-mentioned threshold switch driver part (26,27,50,60) is valve tappet (60).

5. according to the decompressor of 4 any one stroke IC engines of claim 1 to 4, it is characterized in that: above-mentioned relief cam contacting part (33) stretches out to above-mentioned relief cam (35) from the cam rollers support (27a, 50a, 62) of the above-mentioned threshold switch driver part (26,27,50,60) of pivot suspension cam rollers (32).

6. the decompressor of a stroke IC engine, the Aspirating valves (13) and the outlet valve (14) that possess camshaft (19) and drive its switching respectively by air inlet cam (17) and exhaust cam (18) with this camshaft (19) one also have the starter motor that is used to start; The overrunning clutch (34) of relief cam (35) by only could transmitting torque when above-mentioned camshaft (19) reverses is inlaid on the above-mentioned camshaft (19) with at least one adjacent ground connection of above-mentioned air inlet cam (17) and exhaust cam (18); Be provided with when above-mentioned relief cam (35) moves, be associated with this relief cam (35) and make above-mentioned Aspirating valves (13) and outlet valve (14) at least one be in out the threshold switch driver part (26,27,50,60) of valve state, it is characterized in that:

Periphery at above-mentioned relief cam (35) is provided with engaging teat (39), this engaging teat (39) forms plane of inclination (39a) with it becomes reverse directions the place ahead when above-mentioned relief cam (35) reverses a side, (39a) tilts lentamente from the base portion forward end in this plane of inclination, setting is stretched out it by the spring (42) towards the engaging teat (39) of above-mentioned relief cam (35) and is stuck in catch (41) on this engaging teat (39), and this catch (41) connects the cylinder cap (3) that is arranged on internal-combustion engine towards relief cam (35) slidably, the through hole (40a) of the catch support (40) on cylinder head cover or the camshaft holder (44).

7. according to the decompressor of 4 stroke IC engines of claim 6, it is characterized in that: contact with at least one of above-mentioned air inlet cam (17) and exhaust cam (18) and the cam rollers (32) of rotation can be freely rotationally pivot suspension on above-mentioned threshold switch driver part (26,27,50,60), above-mentioned cam rollers (32) has the axial dimension that does not contact with above-mentioned relief cam (35), is provided with the relief cam contacting part (33) that only contacts with above-mentioned relief cam (35) on above-mentioned threshold switch driver part.