CN1103852C

CN1103852C - Structure of cylinder head of IC engine

Info

Publication number: CN1103852C
Application number: CN97125678A
Authority: CN
Inventors: 户坂哲也; 古谷昌志
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 1996-12-27
Filing date: 1997-12-25
Publication date: 2003-03-26
Anticipated expiration: 2017-12-25
Also published as: DE19757286C2; JPH10184445A; CN1186152A; JP3698225B2; DE19757286A1

Abstract

The present invention relates to a structure of cylinder head of an internal combustion engine. In a double upper cam shaft type internal combustion engine provided with a plurality of intake valves and exhaust valves, and a cam shaft for an intake valve and a cam shaft for an exhaust valve, cylinder head fastening parts 46La, 46Ra, 47La, and 47Ra are arranged at the inside of bearings 43L and 43R and bearings 44L and 44R, to support the two cam shafts, and both sides of a plurality of intake valves and a plurality of exhaust valves. The seat surfaces of the cylinder head fastening parts 46La, 46Ra, 47La, and 47Ra are positioned flush with a cylinder head cover mounting surface 4a. In this way, the invention can facilitate machining of a cylinder head, can suppress the generation of vibration, and can compact an internal combustion engine.

Description

The cylinder head structure of internal-combustion engine

Technical field

The present invention relates to the cylinder head structure of 2 overhead camshaft type internal-combustion engines.

Background technique

2 overhead camshaft type internal-combustion engines are put on the shelf in cylinder head and are provided with intake valve camshaft and exhaust valve camshaft, in this 2 overhead camshaft type internal-combustion engine, dispose a plurality of valves on the cylinder head, on each camshaft, have 2 bearings at least, and need the driving mechanism of drive cam shaft, this make to realize that the leeway, space under the occasion of internal-combustion engine miniaturization is few, makes the problem that is configured as that cylinder head is fastened to the used engagement portion of cylinder and crankcase.

Open invention that flat 8-177515 communique put down in writing as shown in figure 16 as the spy of the example of existing 2 overhead camshaft type internal-combustion engines.

Figure 16 is the sectional view of air inlet side of the cylinder head structure of this internal-combustion engine 01, is covered with cylinder cover cap 03 by gasket seal 04 on cylinder head 02, constitutes valve cage.

But the camshaft (not shown) by left and right

sides bearing portion

05,06 free rotaring ground supporting, sprocket wheel 07 is being set holding the camshaft end that portion 05 stretches out from a square shaft, constitutes cam drive mechanism.

Be formed for accommodating the

chamber

08,09 of the valve tappet of intake valve abreast in the left and right sides of cylinder head 02 bearing

portion

05,06 inboard.

Below each bearing

portion

05,06 in a part up and down position overlapped form engagement portion 010,011, insert stud 012,013, cylinder head 02 is fastened on the crankcase with cylinder.

When cylinder cover cap 03 is installed, its upper wall is contacted with bearing portion 06, by bolt 014 that both are fastening.

Because to constitute driving mechanism, so cam driving system becomes the structure that reaches the outside, whole internal-combustion engine maximizes at the arranged outside sprocket wheel 07 of supporting block axle one side's bearing portion 05.

In cylinder head 02, because cylinder head engagement portion 010,011 is positioned at the below with the mating face of cylinder cover cap 03, so need spot-facing when making, cost improves.

The cylinder head fastening position is in below, the mating face of cylinder cover cap 03 time, become problem with the interference of the valve tappet of valve, the

chamber

08,09 that needs as above-mentioned example, to avoid to be used to accommodate valve tappet below bearing

portion

05,06 in a part up and down position overlapped measures such as engagement portion 010,011 are set, thereby cylinder head maximization.

In addition, owing to the upper wall of cylinder cover cap 03 is installed in the bearing portion 06 of camshaft by bolt 014, so the vibration of camshaft is easy to be delivered to cylinder cover cap 03.

Summary of the invention

The present invention makes in view of above problem, and its purpose is to provide a kind of cylinder head structure of internal-combustion engine, and this cylinder head easy processing can suppress vibration, can realize the compactness of internal-combustion engine.

In order to achieve the above object, the invention provides a kind of cylinder head structure of 2 overhead-cam internal-combustion engines, this internal-combustion engine has a plurality of intake valves and exhaust valve, and intake valve camshaft and exhaust valve camshaft are arranged, its cylinder head structure is characterised in that: be provided with and support the bearing of aforementioned intake valve with the two ends of camshaft and aforementioned exhaust camshaft respectively; In the space that bearing and aforementioned intake valve clipped of aforementioned intake valve one side and the space that bearing and exhaust valve clipped of aforementioned exhaust valve one side (and, aforementioned intake valve with the space that camshaft and aforementioned exhaust camshaft clipped in) the cylinder head engagement portion is set; Making the mating face of aforementioned cylinder head engagement portion is same plane with the cylinder cover cap attachment face that is arranged on above the aforementioned cylinder head.

Because the inboard at the bearing that supports two camshafts is provided with the cylinder head engagement portion, so can make the whole internal-combustion engine miniaturization.

Because making mating face, cylinder head engagement portion and cylinder cover cap attachment face is same plane, so do not need spot-facing processing etc., can finish processing with few machining period, can reduce cost.

Because the cylinder head engagement portion is in the both sides of a plurality of valves, and secure engagement face and cylinder cover cap attachment face are at grade, so can not produce interference with the chamber of accommodating valve tappet.

According to the 2nd feature of the present invention, in the combustion engine cylinder head of above-mentioned the 1st feature structure, establish pair of bearings in the two ends of above-mentioned camshaft, between side of this bearing and above-mentioned cylinder head engagement portion, cam drive mechanism is set.

Owing to cam drive mechanism is arranged on the inboard of bearing, so can make the cylinder head miniaturization.

According to the 3rd feature of the present invention, in the cylinder head structure of the internal-combustion engine of above-mentioned the 1st feature or the 2nd feature, cam drive mechanism is made of the cam wheel of being located at above-mentioned each camshaft and the actuation gear that is used to drive above-mentioned cam wheel of being located at jack shaft.

Because cam drive mechanism is the compactly designed of actuation gear and cam wheel engagement, so can make the cylinder head miniaturization.

According to the 4th feature of the present invention, in the cylinder head structure of the internal-combustion engine of above-mentioned the 1st feature, in the inboard of above-mentioned pair of bearings in above-mentioned intake valve with camshaft and above-mentioned exhaust valve arranged outside cylinder cover cap assembly department with camshaft.

Because cylinder cover cap installation position is in the outside of intake valve with camshaft and exhaust camshaft.Do not produce and be configured in the inboard of pair of bearings intrusively with above-mentioned cylinder head engagement portion, thus do not need to enlarge the width of internal-combustion engine on the camshaft direction, in addition owing to the cylinder cover cap being installed dividually, so the vibration of camshaft is difficult for being delivered to the cylinder cover cap with bearing.

Description of drawings

Fig. 1 is the right side view of the internal-combustion engine of one embodiment of the invention.

Fig. 2 is the right sectional view of internal-combustion engine shown in Figure 1.

Fig. 3 is the left side view of internal-combustion engine shown in Figure 1.

Fig. 4 is the left sectional view of internal-combustion engine shown in Figure 1.

Fig. 5 is the worm's eye view of cylinder.

Fig. 6 is the plan view of cylinder.

Fig. 7 is the left side view of cylinder.

The sectional view of Fig. 8 for cutting open along VIII-VIII line among Fig. 6.

The sectional view of Fig. 9 for cutting open along IX-IX line among Fig. 6.

The sectional view of Figure 10 for cutting open along X-X line among Fig. 7.

Figure 11 is the plan view under the state that valve mechanism is installed on the cylinder head.

Figure 12 is the side view of cam box.

Figure 13 is the worm's eye view of cam box.

Figure 14 is for to comprise the sectional view of cutting open on the face of jack shaft.

Figure 15 is for to comprise the sectional view of cutting open on the face of camshaft.

Figure 16 is the sectional view that existing cylinder head structure is shown.

Embodiment

According to Fig. 1～Figure 15 one embodiment of the invention are described below.

The internal-combustion engine 1 of present embodiment is 2 overhead camshaft type single cylinders, 4 stroke IC engines, above cylinder, be provided with 2 valve camshafts that intake valve is used and exhaust valve is used, right side view that it is whole and right sectional view as shown in Figure 1 and Figure 2, left side view and left sectional view are as shown in Figure 3, Figure 4.

Internal-combustion engine 1 is divided into crankcase 2, cylinder 3, cylinder head 4 and cylinder cover cap 5 these several parts substantially, and turns forward a little upward in this order and tiltedly overlap, fit together.

Point to left and right horizontal direction ground supporting crankshaft 10 at crankcase 2 in the mode of pivot suspension, at square one-tenth Transmission Room thereafter, as shown in Figure 2, main shaft 11 can be disposed by the engagement and the clutch 14 transferring power ground of gear 12,13, and disposing countershaft 15 and be configured at the oblique rear down of this main shaft 11 can be by the form of gear group transferring power.

In addition, below bent axle 10, dispose oil pump 16, and driven by the engagement of gear 12,17.

Left end at bent axle 10 is provided with AC generator 19 (with reference to Fig. 3).

As shown in Figure 1, at the place ahead of bent axle 10 configuration oil purifier 18, deliver to bent axle 10 by oily passage A2 again after will being purified from the oil that oil pump 16 is supplied with by oily passage A1, and by oily passage A3 that is formed at right crankcase 2 front side perisporiums and the oily passage A4 that leads to the mating face of cylinder 3 from oily passage A3, after the mating face of cylinder 3 is branched off into air inlet side and exhaust side, rise in cylinder 3, cylinder head 4, Dou oil supplies to valve mechanism.

Fig. 5 illustrates the mating face 3a of cylinder 3 and crankcase 2, is cast into cylinder liner 20 integratedly at the cardinal principle middle position of keeping right slightly, part of stretching out to the left of mating face 3a around it, and the chain that is roughly rectangle that forms long size along fore-and-aft direction is by hole 21.

Mating face 3a around cylinder liner 20 becomes stud hole 22L, 22R, 23L, 23R in 4 dihedrals, the exhaust side stud hole 23R on right side among pairing left and right exhaust side stud hole 23L, the 23R of the air inlet lateral column shape bolt hole 22R on right side and front side (downside among Fig. 5) is also used as oily passage A5, A5 among pairing left and right air inlet lateral column shape bolt hole 22L, the 22R of rear side (upside among Fig. 5).

That is to say, at the mating face 3a of cylinder 3 with crankcase 2, the opening of the above-mentioned oily passage A4 of crankcase 2 is positioned at the right positions of cylinder liner 20, the branch and form oil duct 3b, 3b towards air inlet lateral column shape bolt hole 22R, exhaust side stud hole 23R (being oily passage A5, A5) forwards, backwards from this position.

Therefore, in this mating face 3a branch and by oil duct 3b, 3b forwards, backwards, supply to cylinder head 4 one sides after then in as oily passage A5, the A5 in stud hole, rising from the oily passage A3 of crankcase 2, oil that A4 delivers to cylinder side.

In addition, the rectangle chain on the 3a of the mating face of cylinder 3 is provided with bolt hole 24 by hole 21 left side central authorities, and cylinder sidepiece bolt 25 passes this bolt hole 24 left side of cylinder 3 is fixed on the crankcase 2.

As shown in Figure 2, overlap on this cylinder 3 cylinder head 4 from facing to the mating face of cylinder 3 on 2 inlet holes of firing chamber 30 of cylinder-bore rearward extend to form gas-entered passageway 31,31 respectively, forwards extend to form exhaust passage 32,32 respectively from 2 exhaust ports.Air door body tilts to oblique rear facing to the pairing left and right intake valve 33,33 of each inlet hole, with valve tappet 33a,

33a insertion chamber

38,38 and can it be supported with being free to slide.Equally, air door body tilts to oblique the place ahead facing to the pairing left and right exhaust valve 34,34 of each exhaust port, with valve tappet 34a,

34a insertion chamber

39,39 and can be supported with being free to slide.Each valve 33,33,34,34 is upwards pushed by spring so that closed each hole of air door body.

Article 2, gas-entered passageway 31,31 gathers by connecting tube 35 even 36,2 exhaust passages of rearward Carburetor 32,32 and links outlet pipe respectively.

In addition, the central authorities of firing chamber 30 expose from above the ignition portion of spark plug 37 of setting-in.

Shown in the plan view among Fig. 6, the top of cylinder head 4 forms rectangle substantially, form chain patchhole 41 in the left side and be recessed to the recess 42 of centre spark plug 37 mounting points from right flank, and with periphery as mating face 4a, with the Lower Half of inside recessed formation valve cage with going out.

The valve cage on cylinder head 4 tops forms symmetrically with respect to the center line front and back by spark plug 37 mounting points, rear side is an air inlet side valve cage 60, the front side is an exhaust side valve cage 61, stretch out the 43L of bearing portion, 43R about in air inlet side valve cage 60, stretch out the 44L of bearing portion, 44R about in exhaust side valve cage 61, its upper-end surface and mating face 4a have same height.

As shown in figure 11, but two ends at the 43L of bearing portion, the 43R (with reference to Fig. 6) of exhaust side valve cage about 60 by bearing 64L, 64R free rotaring ground supporting admission cam shaft 62, bearing 64L, 64R are clamped in respectively between the 43L of bearing portion, 43R and left cam holder 66, the right cam holder 67.

Equally, but two ends at the 44L of bearing portion, the 44R (with reference to Fig. 6) of exhaust side valve cage about 61 by bearing 65L, 65R free rotaring ground supporting exhaust cam shaft 63, bearing 65L 65R is clamped in respectively between the 44L of bearing portion, 44R and left cam holder 68, the right cam holder 69.

In addition, between the left side of cylinder head 4 front and back 43L of bearing portion and the 44L of bearing portion, wear from cylinder head left surface left and right horizontal run through the circular hole 45L of chain patchhole 41, and form the diameter smaller circular hole 45R coaxial with this circular hole 45L at chain patchhole 41 walls, thereby jack shaft 70 is embedded into from the left side and is erected at (with reference to Figure 14) on the chain patchhole 41 this circular hole 45L, the 45R.

Jack shaft 70 is made up of the minor diameter 70b that is entrenched in the large-diameter portion 70a among the circular hole 45L and be entrenched among the circular hole 45R, be formed on the tooling hole 71 that connects on the diametric(al) at large-diameter portion 70a, also form the tapped hole 72 parallel in minor diameter 70b end with tooling hole 71.

In the plan view of the cylinder head 4 of Fig. 6, on the 44L of bearing portion, the 44R of the 43L of bearing portion, the 34R of admission cam shaft 62 and exhaust cam shaft 63 upper-end surface before and after separately, be formed for installing bolt thread hole 43La, 43Ra, 44La, the 44Ra of cam holder, wherein the left at the front side bolt hole 43Ra of the 43R of the right side of exhaust cam shaft 62 bearing portion forms air inlet lateral column shape bolt hole 46R, at its left in chain patchhole 41 right-hand formation air inlet lateral column shape bolt hole 46L.

About air inlet lateral column

shape bolt hole

46L, 46R be positioned at the position of clamping

chamber

38,38 front portions from both sides, valve tappet 33a, the 33a of intake valve 33,33 can slide up and down to be contained in this

chamber

38,38.

Form exhaust side column threaded

stud hole

47L, 47R in the place ahead of this air inlet lateral column

shape bolt hole

46L, 46R symmetrical position, exhaust

side stud hole

47L, 47R are in the position at the rear portion of clamping the

chamber

39,39 that is used to accommodate exhaust valve 34,34 valve tappet 34a, 34a from both sides also between the left and right sides bearing 44L of portion, 44R.

The upper end open face of these 4

stud hole

46L, 46R, 47L, 47R that is secure engagement face 46La, 46Ra, 47La, 47Ra and with the mating face 4a of cylinder cover cap 5 (with reference to Fig. 8) at grade.

These 4

stud hole

46L, 46R, 47L, 47R penetrate into the below, respectively with stud hole 22L, 22R, the 23L of above-mentioned cylinder 3,23R aligns and be interconnected.

Stud hole 46R, the 47R on right side continued oily passage A5, the A5 of above-mentioned cylinder 3.

As shown in Figure 9, the air inlet lateral column shape bolt hole 46R on the right side forms oily passage A6, and this oil passage A6 branch obliquely before leaving secure engagement face 46Ra is communicated to contiguous bolt hole 43Ra.

Also form same oily passage A6 at exhaust side stud hole 47R.

Form

bolt thread hole

48L, 48R in position, form bolt thread hole 49L, 49R in position about the cardinal principle symmetry of exhaust cam shaft 63 with exhaust

side stud hole

47L, 47R about the cardinal principle symmetry of camshaft 62 with air inlet lateral column

shape bolt hole

46L, 46R.

Bolt thread hole

48L, 48R, 49L, 49R are the tapped hole that is used to install cylinder cover cap 5, in the outside, front and back of

camshaft

62,63, are positioned at the inboard of the 43L of left and right sides bearing portion, 43R and the 44L of bearing portion, 44R.

Locate to wear respectively the bolt hole 50,51 that is used to install cylinder head 4 slightly more to the right at the left side bearing 43L of portion, 44L.

In addition, also form bolt hole 52 between the 47L at air inlet lateral column shape bolt hole 46L and exhaust side stud, this bolt hole 52 penetrates into above-mentioned circular hole 45R.

As shown in Figure 7, the left surface of this cylinder head 4 forms the mating face 4b with side cover 6 Lower Halves, forms bolt thread hole 53 along this mating face 4b in 4 positions.

In cylinder head 4 above-mentioned intake valve 33,33 and exhaust valve 34,34 are installed, and as shown in Figure 14 above-mentioned jack shaft 70 is embedded among circular hole 45L, the 45R, at this moment, but pass through bearing 73 free rotaring ground supportings and actuation gear 75 all-in-one-piece sprocket wheels 74 at minor diameter 70b, and it is disposed at chain by in the hole 41,55 pairs of jack shafts 70 of flanged pin bolt in screwed joint through bolt hole 52 are fixed in the tapped hole 72 that is formed at minor diameter 70b simultaneously.

Like this, be located among the large-diameter portion 70a of jack shaft 70 tooling hole 71 directed in orthogonal in the direction on the mating face of cylinder 3.

To be assembled into the occasion of crankcase 2 with upper cylinder 3 and cylinder head 4, screwed joint is existed side by side and is established 4 studs 80 in the bolt thread hole of 4 positions of elder generation on the mating face that is formed at crankcase 2 and cylinder 3, then respectively with cylinder 3 air inlet lateral column shape bolt hole 22L, 22R and exhaust side stud hole 23L, 23R aims at upright 4 studs 80 establishing and is inserted into wherein, seal washer 81 ground of packing into therein thus are overlapping with cylinder 3, piston 27 is inserted into cylinder liner 20, an end bearing of connecting rod 26 is connecting piston 27 at its other end with the pivot form at the crank pin of bent axle 10 at this moment.

Then, in the bolt hole 24 in cylinder 3 left sides, insert cylinder sidepiece bolt 25,, and be tightened to temporary fixed state (with reference to Figure 14) the tapped hole of its screwed joint in crankcase 2.

4 stud 80 perforation stud hole 22L, 22R, 23L, 23R also protrude upward.

Then, air inlet lateral column

shape bolt hole

46L, 46R and exhaust side stud hole 47L, the 47R of cylinder head 4 aimed at 4 studs 80 that this stretches out, cylinder head 4 is overlapped on the mating face of cylinder 3 by envelope gasket circle 82.

Because 4 studs 80 run through

stud hole

46L, 46R, 47L, 47R, expose the screw section, upper end from secure engagement face 46La, 46Ra, 47La, 47Ra, so can be with this screw section, upper end of flanged pin nut 83 screwed joint, while and can adjust relative position with cylinder 3 and cylinder head 4 fastening (with reference to Fig. 2 and Figure 11) with respect to crankcase 2.

As shown in figure 14, under the tooling hole 71 of the jack shaft 70 that is set up in cylinder head 4, it is temporary fixed in advance cylinder sidepiece bolt 25, because the head of this bolt forms hexagon ring 25a, so by instruments such as hexagon wrench are connected tooling hole 71 from the top, the end is fitted to the hexagon ring 25a of cylinder sidepiece bolt 25 heads, can fastening cylinder sidepiece bolt 25, the left side of cylinder 3 is fixed to crankcase 2.

In difference inserting bolt 84,84 in the bolt hole 50,51 of cylinder head 4 43L of left side bearing portion, 44L,, thereby cylinder 3 is fixed in the left side of cylinder head 4 with the tapped hole of its screwed joint in cylinder 3.

Between the driving sprocket wheel 78 of sprocket wheel 74 that is supported on jack shaft 70 and bent axle 10, hang chain 79 up (with reference to Figure 14) by hole 21,41 through chain.

Chain 79 carries out appropriate tensioning (with reference to Fig. 4) by chain stretching device 100.

Top air inlet side valve cage 60 and vent systems valve cage 61 in the cylinder head 4 that assembles like this, admission cam shaft 62 and exhaust cam shaft 63 are installed as described above like that, and respectively its two ends are supported by left and right sides cam holder 66,67,68,69 ground free to rotate by bearing 64L, 64R, 65L, 65R.

In addition, cooperate stationary cam gear 76,77 respectively, make itself and actuation gear 75 engagements that are bearing in jack shaft 70 in the left side of admission cam shaft 62 and exhaust cam shaft 63.

Bolt thread hole 43La, 43Ra, 44La, the 44Ra of front and back align separately with the 43L of bearing portion, 43R, 44L, 44R with the bolt hole of left and right sides cam holder 66,67,68,69 before and after separately, with bolt 85 perforations, screwed joint and fastening, the two end part of admission cam shaft 62 and exhaust cam shaft 63 are supported free to rotately.

Wherein, the cam holder 67,69 on right side is a special shape, and the cam holder 69 of exhaust side is as Fig. 1 and shown in Figure 13.

Cam holder 69 forms the rectangular shape that extends substantially on fore-and-aft direction, the recess 69a at left surface formation semicircle shape forms the littler half-round recessed 69b of diameter in its bottom surface, and this recess 69b is by the right side wall obturation.

Before and after this recess 69a, vertically wear

bolt hole

69c, 69d, this

bolt hole

69c, 69d penetrate into the bottom surface, with the mating face 69e of the 44R of bearing portion of bottom surface on, half cycle forms oil duct 69f around a side the bolt hole 69d, oil duct 69f extends to the recess 69b of above-mentioned minor diameter.

Be that bolt hole 69d is communicated with recess 69b by oil duct 69f.

The cam holder 67 of air inlet side forms recess 67a, 67b, bolt hole 67c, 67d, oil duct 67f too, has same structure.

Therefore, when assembling cylinders 3 at crankcase 2, cylinder head 4, and by cam holder 66,67,68,69 supporting

camshafts

61,62 o'clock, the oil of oily passage A4 that flows through crankcase 2 is by means of oil duct 3b, before and after 3b is branched off into, flow to air inlet side and exhaust side, at stud hole 22R by cylinder 3,23R, the stud hole 46R of cylinder head 4, the oily passage A5 that 47 R form, rise among the A5, the oily passage A6 of the inclination branch by cylinder head 4, A6 is from the 43R of bearing portion, the bolt thread hole 43Ra of 44R, 44Ra flows to cam holder 67,69 bolt hole 67d, 69d, and then by oil duct 67f, 69f flows to recess 67b, 69b, as shown in figure 15, from recess 67b, 69b enters into the interior oily passage A7 of axle of admission cam shaft 62 and exhaust cam shaft 63, A7, from this oil passage A7, A7 is branched off into a plurality of oil contents subchannel A8, supplies to cam side face and cam wheel 76,77.

Top in cylinder head 4 is covered upper cylinder half cover caps 5 in mating face 4a place by seal washer 86, bolt thread hole 48L upper wall and cylinder head 4 at

cylinder cover cap

5,48R, 49L, 49R 4 positions in opposite directions form to have bolt hole 88 and be recessed into circular secure engagement face 89 around this bolt hole 88, as shown in Figure 2, the installation rubber 90 of ring-type is entrenched in the recessed secure engagement face 89, flanged pin bolt 91 with being installed, rubber 90 is passed bolt hole 88 and screwed joint in the bolt thread hole of cylinder head 4 48L, 48R, 49L, 49R, fastening (Off ロ one ティ Application グ) is installed in cylinder cover cap 5 on the cylinder head 4 by floating.

That is, be fixed in the flanged pin bolt 91 of cylinder head 4 by means of screwed joint ground, by seal washer 86 with rubber 90 is installed cylinder cover cap 5 is supported on cylinder head 4 with quick condition.

The mating face 4a of the left side wall of cylinder cover cap 5 by seal washer 86 and cylinder head 4 left side walls be (get involved install and seal washer 86 all-in-one-piece cap 86a) in the processing notch portion that prolongs the position that from

camshaft

62,63 of a part of cylinder head 4 together, its left surface forms mating face with side cover 6 with the mating face 4b of cylinder head 4, forms bolt thread hole 92 in 4 positions of outer periphery on this mating face.

That is, the outer side surface of the left side wall of cylinder head 4 and cylinder cover cap 5, constitute the mating face along a week in its periphery, 4 positions on this mating face in cylinder head 4 one sides form bolt thread hole 53, form bolt thread hole 92 in 4 positions of cylinder cover cap 5 one sides with being integral.

On this mating face from the left side cover side cover 6.

As shown in Figure 3, side cover 6 is flat lid, is made of the big rounded portions 6a of central authorities and stretch out rounded portions 6b, the 6c that stretch out forwards, backwards, is covered by perisporium 6d around its diapire.Perisporium 6d forms and bolt thread hole, 8 place 53,92 bolt hole 93 in opposite directions corresponding to the mating face of above-mentioned cylinder head 4 and cylinder cover cap 5.

This side cover 6 is covered on the left surface of cylinder 4 and cylinder cover cap 5 and between the mating face, get involved installation seal washer 94, bolt hole 93 is alignd with bolt thread hole 53,92 respectively, as shown in Figure 15 with cylindraceous, at one end form the installation rubber 95 stud bolt holes 93 of flange, flanged pin bolt 96 is connected wherein and bolt thread hole 53,92 screwed joint, and fastening form is installed on cylinder head 4 and cylinder cover cap 5 with side cover 6 to float.

That is flanged pin bolt 96 is fixed in cylinder head 4 and cylinder cover cap 5 with screwed joint, with quick condition side cover 6 is installed on cylinder head 4 and cylinder cover cap 5 by seal washer 94 and installation rubber 95 by this flanged pin bolt 96.

In the side cover of installing like this 6, as shown in Figure 3, axle center S1, the S2 (with reference to Fig. 4) with admission cam shaft 62, exhaust cam shaft 63 is different respectively at each center c1, c2 of stretching out rounded portions 6b, 6C of fore-and-aft direction, is in along the position of front and back biasing.

This internal-combustion engine 1 is assembled as described above.

Admission cam shaft 62, exhaust cam shaft 63 support its two ends by the 43L of bearing portion, 43R and the 44L of bearing portion, 44R, cam drive mechanisms such as sprocket wheel 74, actuation gear 75, camshaft gear wheel 76,77 are arranged in the inboard of the 43L of left bearing portion, 44L, because secure engagement face 46La, 46Ra, 47La, the 47Ra of bolt shape bolt 80 on cylinder head 4 that cylinder head 4 and cylinder 3 are fastened on crankcase 2 together is located at the inboard of the 43L of left and right sides bearing portion, 43R and the left and right sides bearing 44L of portion, 44R, so the left and right sides width of cylinder head 4 is reduced, make internal-combustion engine 1 overall compactization.

Because the secure engagement face 46La of cylinder head 4,46Ra, 47La, 47Ra and with the mating face 4a of cylinder cover cap 5 on one side, so do not need spot-facing processing etc., can reduce labor content, reduce cost.

Because secure engagement face 46La, 46Ra, 47La, 47Ra and with the mating face 4a of cylinder cover cap 5 at grade, even so near the both sides of the

chamber

38,39 that is used to accommodate valve tappet 33a, 34a, can not produce yet and disturb, can make internal-combustion engine 1 miniaturization thus with

chamber

38,39.

Because the bolt thread hole 48L as cylinder cover assembly department of

cylinder head

4,48R, 49L, 49R are in the outside of admission cam shaft 62 and exhaust cam shaft 63, do not produce the inboard that is configured in the 43L of left and right sides bearing portion, 43R and the left and right sides bearing 44L of portion, 44R intrusively with cylinder head secure engagement face 46La, 46Ra, 47La, 47Ra, so can realize the miniaturization of internal-combustion engine 1, in addition, owing to by flanged pin bolt 91 the cylinder cover cap 5 and the cam holder 66,67,68,69 of bearing are installed dividually, so the vibration of

camshaft

62,63 is difficult for passing to cylinder cover cap 5.

Claims

1. the cylinder head structure of an internal-combustion engine, this internal-combustion engine are a plurality of intake valves and exhaust valve to be arranged and the 2 overhead camshaft type internal-combustion engines of intake valve with camshaft and exhaust camshaft are arranged; It is characterized in that:

Be provided with and support the bearing of aforementioned intake valve respectively with the two ends of camshaft and aforementioned exhaust camshaft;

In the space that bearing and aforementioned intake valve clipped of aforementioned intake valve one side and the space that bearing and exhaust valve clipped of aforementioned exhaust valve one side (and, aforementioned intake valve with the space that camshaft and aforementioned exhaust camshaft clipped in) the cylinder head engagement portion is set;

Making the mating face of aforementioned cylinder head engagement portion is same plane with the cylinder cover cap attachment face that is arranged on above the aforementioned cylinder head.

2. combustion engine cylinder head as claimed in claim 1 structure, it is characterized in that: pair of bearings is established at the two ends at above-mentioned camshaft, between this is to side of bearing and above-mentioned cylinder head engagement portion cam drive mechanism is set.

3. combustion engine cylinder head as claimed in claim 1 or 2 structure is characterized in that: cam drive mechanism is made of the camshaft gear wheel of being located at above-mentioned each camshaft and the actuation gear that is used to drive above-mentioned camshaft gear wheel of being located at jack shaft.

4. combustion engine cylinder head structure as claimed in claim 1 is characterized in that: in the inboard of above-mentioned pair of bearings, use the arranged outside cylinder cover cap assembly department of camshaft with camshaft and above-mentioned exhaust valve in above-mentioned intake valve.