JPH04134103A - Valve gear for v-type five valve engine - Google Patents

Abstract

PURPOSE:To get rid or any overhang to the V-bank inside of a cover housing a chain wheel of the like as well as to expand a space in the bank by bringing an inlet camshaft near to the side of a cylinder shaft center, while installing the intermediate chain wheel at the exhaust side after being deflected. CONSTITUTION:Three inlet openings and two exhaust openings are formed in a combustion recess in the lower part of a cylinder head 4, and these openings are opened or closed by an inlet valve 14 and an exhaust valve 15. These inlet and exhaust valves 14, 15 are opened or closed by each rotation of an inlet camshaft 24 and an exhaust camshaft 25, and these camshafts 24, 25 are driven by a crankshaft 9 via an intermediate gear train. At this time, a distance A betwee the inlet camshaft 24 and a cylinder shaft center should be set to be smaller than that (a distance B) between the exhaust camshaft and the cylinder shaft center C, and an intermediate chain wheel 35 driving both inlet and exhaust cam chain wheels 24a, 25a attached tight to those of inlet camshaft 24 and exhaust camshaft 25 is made so as to be installed in an interval between both cam chain wheels 24a, 25a and the crankshaft 9 and in a position deflected to the exhaust side from the cylinder shaft center C as looking in the crankshaft direction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a valve operating system for a V-type five-valve engine, and more particularly to an arrangement structure of a drive mechanism that allows the space inside the bank to be expanded.

[Conventional technology]

A 4-stroke V-type engine has cylinders (
Generally, the cylinder bore (cylinder bore) is formed in a figure 7 shape when viewed in the direction of the crankshaft, and a pair of cylinder heads and head covers are stacked and fastened on the cylinder block to form a V bank. The valve train for this type of engine is provided with an intake camshaft and an exhaust camshaft that directly drive the intake valve and exhaust valve, respectively, and each camshaft is driven by a crankshaft via a gear train, chain, heald, etc. It is often configured as follows.

[Problem to be solved by the invention]

In the V-type engine mentioned above, there are cases where various engine accessories and other parts are placed inside the bank.In such cases, the space inside the V bank can be expanded to increase the space for placing the aids. At the same time, it is required to be able to secure the maintenance space. However, depending on the arrangement of the valve train, the valve train accommodation case portion etc. may protrude into the V bank, making it impossible to meet the above-mentioned request for expanding the bank internal space.

The present invention has been made in view of the above-mentioned conventional situation, and an object of the present invention is to provide a valve operating system for a four-stroke type engine that can expand the space inside the V bank.

[Failure to solve the problem]

In the present invention, three intake valves are arranged on one side of the combustion chamber, and two exhaust valves are arranged on the other side, and the inclination angle of the central intake valve with respect to the cylinder axis is smaller than the inclination angle of the intake valves on both sides. Position the intake valve so that it faces the combustion chamber.

an intake camshaft that directs the intake opening and exhaust opening opened and closed by the exhaust valve to the inside and outside of the V-bank through an intake passage and an exhaust passage, respectively, and directly drives these valves above the intake valve and the exhaust valve; An exhaust camshaft is provided, the distance between the intake camshaft and the cylinder axis is set smaller than the distance between the exhaust camshaft and the cylinder axis, and the intake and exhaust cam chains are fixed to the intake camshaft and exhaust camshaft. The present invention is characterized in that an intermediate chain wheel for driving the vehicle is disposed between both of the cam chain wheels and the crankshaft, and at a position offset from the cylinder axis toward the exhaust side when viewed in the direction of the crankshaft.

Here, the valve operating device of the present invention includes one using a gear train, one using a timing heald, and one using a timing heald. Therefore, the above-mentioned cam chain wheel means a cam gear, a cam sprocket, and a cam pulley, and the above-mentioned intermediate chain wheel means an open gear intermediate sprocket and an intermediate pulley. In addition, the mode in which the camshaft is driven by the intermediate chain wheel is as follows:
A method in which the intermediate gear is engaged with both the intake and exhaust cam gears, a method in which the intermediate sprocket is connected to both or one of the intake and exhaust cam sprockets with a chain, or a method in which the intermediate sprocket is connected to both the intake and exhaust cam pulleys with a heddle, or This includes various methods such as connecting to one side.

[Effect]

According to the valve train according to the present invention, ■ the intake system is arranged inside the bank and the exhaust system is arranged outside, the intake camshaft is moved closer to the cylinder axis side, and the intermediate chain wheel that drives the camshaft is arranged. Since they are deviated from the cylinder axis toward the exhaust side, the case that houses them will not protrude inside the V bank (therefore, the space within the bank will be expanded accordingly).

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

1 to 5 are diagrams for explaining a valve train for a four-stroke V-type engine according to a first embodiment of the present invention, in which FIG. 1 is a front view, FIG. 2 is a rear view, and FIG. The figure is a sectional front view, FIG. 4 is a sectional front view of the cylinder head portion, and FIG. 5 is a plan view of the upper head portion. This is an 8-cylinder engine with a crankcase 3 attached to the bottom of the cylinder block 2.
A pair of left and right cylinder heads on the top surface 4. head cover 5
It has a structure in which these are laminated and fastened together. A total of S cylinders (cylinder bores) 6 are formed in the cylinder block 2 so as to form a V-shape when viewed in the direction of the crankshaft, and the piston 7 inserted into the cylinder 6 is connected to the crankshaft with a convex loft 8. Nine pieces are connected.

The cylinder head 4 has a lower head 10 and an upper head 1.
1, and a combustion recess 12 is formed in the lower surface of the lower head 10 and forms a combustion chamber with the upper surface of the piston 7. This combustion recess 12
includes three intake openings 12a to 12c and two exhaust openings 12d.

12e is formed along the periphery of the combustion recess 12, and a spark plug insertion hole 12] is formed in the center.

The exhaust openings 12d and 12e are exhaust passages 13d and 13e.
is led out to the bank outer wall 10b of the cylinder head 4. Further, the intake openings 128 to 12C are led out to the bank inner wall 10a of the cylinder head 4 by the intake passages 13a to 13C, and are merged at an upwardly extending portion 11c of the upper head 11, and the merged portion 13f
1 is a mounting hole 1 formed in the center intake passage 13b, which has an oval shape 1 extending horizontally in the direction of the crankshaft.
A fuel injection valve 30 is attached to the fuel injection valve 1d, and a slide pulp 39 for opening and closing the merging portion 13f is provided on the extension portion 11C, and an air horn 40 is further connected to the extension portion 11C. Note that 41 is a cover that prevents dirt and the like from entering the air horn 41.

Further, a water cooling jacket is formed inside the lower head 10 so as to cover the upper part of the combustion recess 12 . This water cooling jacket includes an intake side jacket 31a located from the intake passages 132 to 13C to the inner wall 10a side of the lower head 10, and the exhaust passages 13d and 1.
It is composed of an exhaust side jacket 31b located from the portion 3e to the outer wall 10b side, and a central jacket 31C located between the intake passage and the exhaust passage. Further, at a position connecting the upper ends of the center jacket 31c and the intake side jacket 31a, the left and right intake passages 13a,
A communicating hole 31e is formed by drilling at a position sandwiching 13c.
is formed. The cooling water flows into the exhaust side jacket 31b from the water cooling jacket (not shown) of the cylinder block 2, and flows out from the central jacket 31c and the intake side jacket 7 31a to the drain port 31d. Furthermore, when the supply of cooling water is started, the air in the central jacket 31C is exhausted to the intake side jacket 31a side through the communication hole 31e.

and the above-mentioned intake openings 12a to 12C9 exhaust openings 12d,
12e has an intake valve 14. Valve plate portion 14a, 1 of exhaust valve 15
5a are arranged respectively.

The upper ends of the valve stems 14b, 15b of each valve 14.15 are formed in the guide holes 11a, llb formed in the upper rod 11.
Located within. Furthermore, the angle of inclination of the central intake valve 14' with respect to the cylinder axis C is smaller than the angle of inclination of the intake valves 14 on both sides, and when viewed in the direction of the crankshaft, the axes of these three intake valves 14 are They intersect at the axial center of an intake camshaft 24, which will be described later. These guide holes 11a and llb are formed in such a way that they are continuous in the radial direction, 3 each, and 2 each, that is, in a size that eliminates the boundary wall. , exhaust inserts 16.17 are cast in. Intake and exhaust lifters 18 and 19 each having a cylindrical shape with a bottom are slidably inserted into the sliding holes formed in the intake and exhaust inserts 16.17. The upper end surfaces of the valve rods 14b and 15b are in contact with the inner side via a stopper. Further, a retainer 20.21 is attached near the upper end of the valve stems 14b, 15b.
0.21 and 12g of spring seats formed on the lower head.
, 12h, there is a double structure intake/exhaust biasing spring 22.
, 23 are interposed.

As a result, the intake and exhaust valves 14 and 15 are biased in the direction of closing the intake and exhaust openings. Moreover, the above-mentioned intake lifter 18. The intake camshaft 24. is in rolling contact with the exhaust lifter 19. An exhaust camshaft 25 is arranged, and an intake camshaft 2
The distance MA from the exhaust camshaft 25 to the cylinder axis C is set smaller than the distance @B from the exhaust camshaft 25 to the cylinder axis C. Each of the camshafts 24.25 is pivotally supported by a bearing portion formed on the upper head 11 and a cam cap 32 fixed with a pole 32a, and the cam ridges of each camshaft 24.25 are By pushing down each intake and exhaust lifter 18, 19 mentioned above, the intake valve 14. The exhaust valve 15 is moved downward.

At the front end of the engine 1 is the intake camshaft 24.
A camshaft drive mechanism is provided in which the exhaust camshaft 25 is driven by the crankshaft 9 via three sets of intermediate gears, and the drive mechanism is covered with a gear cover 36. The drive mechanism meshes a crank gear 9a integrally formed at the end of the crankshaft 9 with a large gear 33a of the first intermediate gear 33,
The small gear 33b of the first intermediate gear 33 is connected to the second intermediate gear 34.
The small gear 34b is meshed with the third large gear 34a.
The third intermediate gear 35 is meshed with an intermediate gear 35, and the third intermediate gear 35 is meshed with an intake cam gear 24a and an exhaust cam gear 25a. Note that 44a is the crankshaft 9
A lubricating oil passage 44b formed inside is a lubricating oil passage 44a.
An oil hole 37 is a plug for closing an opening created during machining of the hydraulic passage 44a, and an air vent hole 37a is provided at the downstream end of the plug 37' in the figure.
is formed.

The first intermediate gear 33 is shared by the front and rear cylinders, and is located at the center of the bank. It is supported by a support shaft 33d via a bearing 33c. The support shaft 33d pivotally supports the first intermediate gear 33, and is press-fitted into an end opening of the main gear lary 2a, which is a main lubricating oil passage formed in the cylinder block 2 in parallel with the crankshaft. 2a is occluded.

Also, the above 2. The third intermediate gears 34 and 35 have independent front and rear cylinders, and their tips are pivotally supported by a gear cover 36 via a bearing 44. Here, the second
The support shaft 34C of the intermediate gear 34 is located at the cylinder axis C1, whereas the support shaft 35a of the third intermediate shaft 35 is offset by D from the cylinder axis C toward the exhaust side. As a result, the intermediate gear 35 is simultaneously meshed with the intake and exhaust cam gears 24a and 25a, which are disposed at different distances from the cylinder axis C to A and B, respectively.

In addition, in the area between the front and rear cylinder heads 4 and 4,
A generator 54, which is an engine accessory, is provided, and its flange portion 54a is bolted to a support bracket portion 10d integrally formed with the lower head 10.

Next, the effects of this embodiment will be explained.

In this embodiment, since the intake camshaft 24 is arranged closer to the cylinder axis C side than the exhaust camshaft 25, the third intermediate shaft 35 can be deviated from the cylinder axis C to the exhaust side by D.
The gear cover 36 that covers the drive mechanism does not protrude inside the bank. Therefore, the space inside the bank can be expanded accordingly, and relatively large auxiliary tools such as the generator 54 can be placed inside the bank without any problem, and space for maintenance thereof can also be secured.

Furthermore, since the support shaft 33d of the first intermediate shaft gear 33 is press-fitted into the end of the main gear rally 2a, the support shaft 33d can also be used to close the end opening of the main gear rally 2a, and there is no need to separately provide a plug or the like for blocking. There is no.

In the above embodiment, the rotation of the crankshaft is transmitted to the camshaft using a gear train, but the present invention can of course be applied to a timing chain or a timing belt.

Figures 6 and 7 are examples using a timing belt,
In the figure, the same reference numerals as in FIGS. 1 and 2 indicate the same or equivalent parts, which are arranged below the crank pulley 9b fixed to the end of the crankshaft 9 and the intake and exhaust camshafts 24 and 25. The large diameter pulley 42a of the intermediate boot +J 42 is connected by a first timing belt 43a. In addition, the small diameter pulley 42b of the intermediate boob 1J42 and the intake cam pulley 24b,
and the exhaust cam pulley 25b is the second timing belt 4.
3b. Also, 42C is a large diameter pulley 42
42d is a tensioner for adjusting the tension of the heald, and these camshaft drive mechanisms are covered with a pulley cover 36.

The distances from the cylinder axis C to the intake camshaft 24 and the exhaust camshaft 25 are A and B, respectively, and the support shaft 42e of the intermediate pulley 42 is located on the exhaust side from the cylinder axis C.
is deviated only. Accordingly, in this embodiment as well, the pulley cover 36 does not protrude inside the bank, and the space for arranging auxiliary tools and the like in the bank and the space for maintenance can be expanded.

〔Effect of the invention〕

As described above, according to the valve train for a V-type 5-valve engine according to the present invention, the intake camshaft is moved closer to the cylinder axis side, and the intermediate chain wheel is deviated toward the exhaust side, so that the chain wheel etc. ■The cover that accommodates the bank does not protrude inside the bank, and the space inside the bank can be expanded accordingly, which has the effect of securing space for auxiliary equipment, etc., and space for maintenance.

[Brief explanation of the drawing]

1 to 5 are diagrams for explaining a valve train for a four-cycle engine according to a first embodiment of the present invention. FIG. 1 is a front view of the engine of the embodiment, and FIG. 2 is a rear view thereof. 3 is a sectional view of the intermediate gear portion, FIG. 4 is a sectional front view of the cylinder head portion, FIG. 5 is a plan view of the upper head portion, and FIGS. 6 and 7 illustrate the second embodiment. They are a front view and a rear view. In the figure, 1 is a 4-stroke V-type engine, 9 is a crankshaft, 12a to 12C are intake openings, 12d and 12e are exhaust openings, 13a to 13c are intake passages, 13d and 13e
are exhaust passages, 14.15 are intake and exhaust valves, 24.25 are intake and exhaust camshafts, 24a and 24b are intake cam gears, intake cam pulleys (intake cam chain wheels), 25a and 25b are exhaust cam gears, and exhaust cam pulleys (exhaust). cam chain wheel), 35.
42 is the third intermediate gear, intermediate pulley (intermediate chain wheel), AB
is the distance between the intake and exhaust camshafts and the cylinder axis, C is the cylinder axis, and D is the eccentric position.

Claims (1)

[Claims] (1) Three intake valves are arranged on one side of the combustion chamber and two exhaust valves are arranged on the other side, and the inclination angle of the central intake valve with respect to the cylinder axis is smaller than the inclination angle of the intake valves on both sides. The intake and exhaust openings, which are opened and closed by the intake and exhaust valves, are guided to the inside and outside of the V-bank through the intake passage and the exhaust passage, respectively, above the intake and exhaust valves. An intake camshaft and an exhaust camshaft that directly drive these valves are arranged in , the intermediate chain wheel that drives the intake and exhaust cam chain wheels, which are fixed to the exhaust camshaft, is located between the two cam chain wheels and the crankshaft, and is shifted toward the exhaust side from the cylinder axis when viewed in the direction of the crankshaft. A valve train for a V-type 5-valve engine, characterized in that it is arranged in a position where