JP2001227305A - Valve system of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve rigidity among plural holding parts while restraining increase of weigh of a holder on which plural holding parts to hold plural energizing members are provided, in a valve system of an internal combustion engine. SOLUTION: This valve system of an internal combustion engine is furnished with plural energizing members 31-35 to energize plural locker arms 17-19, 23, 24 to be interlocked with an engine valve made of an air intake valve and an exhaust valve by bouncing force and a holder 50 on which plural holding parts 51-55 to hold those energizing members 31-35 are provided. Rigidity between the holding parts 51-53 or the holding parts 54, 55 is improved as at least the two holding parts 51, 52, 53 are directly connected to each other and integrated or at least the two holding parts 54, 55 are directly connected to fastening parts C1, C4, C7, C10 to install the holder 50 on an engine main body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake valve which is an engine valve having a plurality of rocker arms which are directly or indirectly oscillated by a cam provided on a cam shaft, and which are opened and closed in conjunction with the rocker arms. More specifically, the present invention relates to a valve train for an internal combustion engine having a valve and an exhaust valve, and more particularly, to a plurality of holding members respectively holding a plurality of biasing members for biasing a plurality of rocker arms toward an engine valve or a cam by an elastic force. The present invention relates to a holder in which a portion is formed.

[0002]

2. Description of the Related Art Conventionally, camshafts have been used to improve fuel efficiency and output by switching valve opening characteristics such as lift amount of an intake valve or an exhaust valve which is an engine valve of an internal combustion engine according to an engine operating state. 2. Description of the Related Art A valve operating device for an internal combustion engine is known in which a plurality of rocker arms oscillated by a plurality of cams having different profiles are provided with a connection switching mechanism for switching the rocker arms between a connected state and a disconnected state.

[0003] For example, in the valve gear of an internal combustion engine disclosed in Japanese Utility Model Laid-Open Publication No. 4-1606, each cylinder comes into sliding contact with a raised portion provided on a cam shaft and a low speed cam, and a pair of intake valves is provided. Are provided with a pair of drive rocker arms which are respectively linked and connected to each other, and one free rocker arm which is in sliding contact with the high-speed cam and which can be free with respect to the intake valve, and which can switch connection and disconnection of the rocker arms. A switching mechanism is provided. The free rocker arm swung by the high-speed cam
At the time of low-speed operation of the engine, a lost motion mechanism is provided that urges the free rocker arm toward the high-speed cam in order to prevent the free rocker arm from running away irrespective of the intake valve.

This lost motion mechanism is fitted to a bottomed cylindrical portion provided on a support plate fixed to a cylinder head. The support plate is provided with a rib for connecting the bottomed cylindrical portion and the fastening portion of the support plate, so that the rigidity of the entire support plate is increased, and based on the sliding contact between the high-speed cam and the free rocker arm. The deformation of the support plate around the bottomed cylindrical part caused by the load acting on the lost motion mechanism is also suppressed, and as a result, the malfunction of the lost motion mechanism due to the deformation occurs. For example, the elastic force is larger than the set elastic force. Is suppressed, the action direction of the resilient force is deviated from the set direction, and the sliding motion of the sliding portion is not performed smoothly.

[0005]

In the prior art, since only one lost motion mechanism as an urging member is provided for each cylinder, a plurality of lost motion mechanisms due to the load acting on the lost motion mechanism are provided. Deformation of the support plate between the bottom cylindrical portions is suppressed to some extent by the ribs. However, a plurality of lost motion mechanisms are provided in each cylinder, for example, as in the valve operating device of a multi-cylinder internal combustion engine disclosed in Japanese Patent Application Laid-Open No. Hei 8-61031, and the lost motion mechanisms are provided with a plurality of holding plates of a support plate. When each of the holding portions is held by each of the holding portions, the support plate between the plurality of holding portions is easily deformed by the load acting on each of the holding portions.
Therefore, in order to increase the rigidity of the support plate between the plurality of holding portions, to increase the thickness of the entire support plate, or to further provide a rib between the plurality of holding portions,
Since the weight of the internal combustion engine is increased, the fuel efficiency is deteriorated and the cost is increased.

The present invention has been made in view of such circumstances, and the invention according to claims 1 to 4 is directed to a valve train for an internal combustion engine having a plurality of biasing members. A common object is to increase rigidity between a plurality of holding portions while suppressing weight increase of a holder provided with a plurality of holding portions for holding the urging members. The fourth object of the present invention is to further increase the rigidity of the entire holder.

[0007]

According to the first aspect of the present invention, a plurality of rocker arms which can swing directly or indirectly by a cam provided on a camshaft and can interlock with an engine valve are provided. A plurality of biasing members for biasing the engine valve or the cam toward each other by a resilient force, and a holder attached to the engine body and provided with a plurality of holding portions for respectively holding the biasing members. A valve operating device for an internal combustion engine provided with at least two holding portions that are directly connected and integrated with each other.

According to the first aspect of the present invention, the at least two holding portions for holding the urging members are integrated by directly connecting the holding portions, so that the holding portions reinforce each other. As a result, the rigidity between the holding portions is increased, so that the deformation between the holding portions can be suppressed, and the occurrence of a failure of the urging member can be suppressed. Then, by using the mutual holding portions themselves, the rigidity between the holding portions can be increased without additionally forming a new reinforcing structure on the holder,
An increase in the weight of the holder can be suppressed. Further, since the holding parts are directly connected to each other and integrated, a plurality of holding parts can be arranged compactly.

According to a second aspect of the present invention, in the valve train of the internal combustion engine according to the first aspect, the at least two holding portions directly connected to each other have a bottomed hole and are opened to the rocker arm side of the holder. And a through-hole having a through-hole penetrating the holder and having a first open end opened to the rocker arm side and a second open end opened to the anti-rocker arm side of the holder. A part of the urging member is held in the bottomed hole of the bottomed holding part, and the through hole of the through-holding part is formed from the second opening end of the urging member. An urging member formed so as to be attachable to the through hole is held.

According to the second aspect of the present invention, the at least two holding portions which are directly connected and integrated are formed by a combination of a bottomed holding portion and a through holding portion. As a result, since the integrated holding portion includes a bottomed holding portion having a bottom instead of a through hole, rigidity between at least two holding portions can be increased, and at the same time, the holder is attached to the engine body. After the mounting, by using the through hole, the biasing member can be mounted to the through hole from the second opening end of the holder, which is open to the anti-rocker arm side where the valve mechanism such as the rocker arm is not provided. Can be easily mounted, and the workability of assembling the urging member can be improved.

According to a third aspect of the present invention, a plurality of rocker arms which can swing directly or indirectly by a cam provided on a camshaft and are interlocked with an engine valve are resiliently directed toward the engine valve or the cam. In a valve operating device for an internal combustion engine comprising: a plurality of biasing members for biasing by force; and a holder attached to the engine body and provided with a plurality of holding portions for respectively holding the biasing members. The holding portion is a valve operating device for an internal combustion engine in which each of the holding portions is directly connected to a fastening portion of the holder for attaching the holder to the engine body, and integrally connected via the fastening portion. .

According to the third aspect of the present invention, each of the at least two holding portions is directly connected to the fastening portion that is coupled to the engine body in the holder and is integrated therewith. As a result, the deformation between the holding portions can be suppressed, and the occurrence of a failure of the urging member can be suppressed. In addition, since the vicinity of the fastening portion where the holding portion is located has high rigidity, deformation of the entire holder due to a load acting via the urging member based on rocking of the rocker arm can be suppressed.

According to a fourth aspect of the present invention, in the valve train of an internal combustion engine according to any one of the first to third aspects, the holder extends along an axial direction of the camshaft. A first rib for connecting the holding portions to each other, and a second rib for connecting a fastening portion of the holder for attaching the holder to the engine body, the holding portion being different from the holding portion connected to the first rib, and the holder. And a second rib is provided between the holding portion and the fastening portion, which are connected to each other.
It is connected to the rib.

According to the fourth aspect of the present invention, the first rib formed extending in the axial direction of the camshaft and the second rib connected to the first rib between the holding portion and the fastening portion. As a result, the rigidity of the entire holder is increased, so that the occurrence of malfunction of the biasing member is further suppressed, the operation of the valve gear is stabilized, and the vibration is suppressed,
Noise is reduced.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. In this embodiment, the internal combustion engine is a 6-cylinder V-type SOHC internal combustion engine for a vehicle, and the cylinders forming one bank of the internal combustion engine are in an engine operation range where fuel efficiency is important such as a low load operation range. The opening and closing operations of the intake valves and the exhaust valves of these cylinders are stopped, and the cylinders are brought into a stopped state.

Referring to FIG. 1, FIG. 3 to FIG. 5, in a bank on the deactivated cylinder side, a cylinder which is coupled to a cylinder block (not shown) and forms a part of an engine body of the internal combustion engine together with the cylinder block. The head 1 has an intake valve 5a which is a pair of engine valves for opening and closing the intake ports of a pair of intake ports 3 opened to the combustion chamber 2 for each of the three cylinders A1, A2, A3 arranged along the crankshaft. , 5b and combustion chamber 2
Exhaust valves 6a and 6b, which are a pair of engine valves, that open and close the exhaust ports of the pair of exhaust ports 4 that open to the outside. A cylinder head cover is connected to the upper end surface of the cylinder head 1 to form a sealed valve operating chamber in which the valve operating device is housed. FIG. 1 shows a portion corresponding to each cylinder,
These are indicated by reference signs A1, A2, and A3.

In each cylinder A1, A2, A3, a pair of intake valves
5a and 5b are slidably fitted to a stem guide 7 press-fitted into the cylinder head 1 and are compressed by a valve spring 11 mounted between the cylinder head 1 and a flange 9 at a valve stem end. , And are biased in the valve closing direction. Similarly, a pair of exhaust valves 6
a and 6b are also slidably fitted to a stem guide 8 press-fitted into the cylinder head 1, and are compressed by a valve spring 12 mounted between the cylinder head 1 and a flange 10 at the valve stem end. , And are biased in the valve closing direction.

A camshaft 13 rotatably driven at a reduction ratio of 1/2 by a crankshaft of the internal combustion engine is rotatably supported by the cylinder head 1. The camshaft 13 has an intake cam 14, a pair of exhaust pause cams 15a and 15b located on both sides of the intake cam 14 along the camshaft 13, and an intake cam 14 for both exhaust pause cams 15a and 15b. A pair of exhaust cams on the opposite side
16a and 16b are provided. The intake cam 14 has a profile consisting of a lift portion for opening and closing the pair of intake valves 5a and 5b during normal operation of the internal combustion engine and a base circle portion, and both exhaust stop cams 15a and 15b Has a profile consisting of only a base circle portion that closes the exhaust valves 6a and 6b,
Each of the exhaust cams 16a and 16b has a profile including a lift portion and a base circular portion that respectively open and close the pair of exhaust valves 6a and 6b during normal operation of the internal combustion engine.

Between the pair of intake valves 5a, 5b and the camshaft 13, there are first and second intake rocker arms 17, 18, and a third intake rocker arm 19 located between the two intake rocker arms 17, 18.
Are swingably supported above the camshaft 13 in a state of being arranged in parallel with the intake rocker arm shaft 20 fixed to the cylinder head 1. On the other hand, between the pair of exhaust valves 6a, 6b and the camshaft 13, the first and second exhaust rocker arms 21, 22 and the third and third exhaust rocker arms 21, 22 located on both sides thereof with the exhaust rocker arms 21, 22 therebetween.
The fourth exhaust rocker arms 23 and 24 are swingably supported above the cam shaft 13 in a state of being arranged in parallel with an exhaust rocker arm shaft 25 fixed to the cylinder head 1.

In each of the first and second intake rocker arms 17 and 18, one end is supported by an intake rocker arm shaft 20, and the other end is provided with a tappet screw which is in contact with the valve stem end of the intake valves 5a and 5b. 26 is provided so as to be able to advance and retreat, and a first connection switching mechanism M1 described later is provided at an intermediate portion thereof.
Also, as shown in FIG. 3, the third intake rocker arm
A roller 28 slidingly in contact with the intake cam 14 is rotatably supported at one end of the 19, and a first connection switching mechanism M 1 is provided at the other end, and an intermediate portion thereof is supported by the intake rocker arm shaft 20. Therefore, the first and second intake rocker arms 17 and 18 are connected to both intake valves 5.
a, 5b, respectively, the third intake rocker arm 19,
It is swung directly by the intake cam 14.

On the other hand, the first and second exhaust rocker arms 21 and 22
At one end, an exhaust pause cam 15
A roller 29 having a second connection switching mechanism M2, which will be described later, is rotatably supported, and a tappet screw 27 abutting on the valve stem end of the exhaust valves 6a, 6b advances and retreats at the other end. It is provided freely, and the middle part is the exhaust rocker arm shaft
Supported by 25. As shown in FIG. 7, the roller 29 includes an inner ring 29a press-fitted and fixed to the first and second exhaust rocker arms 21 and 22, an outer ring 29b slidably contacting the exhaust pause cams 15a and 15b, and an inner ring 29a and an inner ring 29a, respectively. And a number of rollers 29c arranged between the outer rings 29b. Further, in each of the third and fourth exhaust rocker arms 23 and 24, a roller 30 having a built-in second connection switching mechanism M2 is supported at one end by sliding contact with the exhaust cams 16a and 16b. The end is supported by the exhaust rocker arm shaft 25. Roller 30
The inner ring 30a is press-fitted and fixed to the third and fourth exhaust rocker arms 23 and 24, and the outer ring 30b is in sliding contact with the exhaust cams 16a and 16b.
It comprises a number of rollers 30c arranged between the inner ring 30a and the outer ring 30b. Therefore, the first and second exhaust rocker arms 21 and 22 are interlocked with the two exhaust valves 6a and 6b, respectively,
The fourth exhaust rocker arms 23 and 24 are directly swung by the two exhaust cams 16a and 16b, respectively.

Thus, the first and second intake rocker arms
Reference numerals 17 and 18 denote free rocker arms which can be free without being restricted by the movement of the intake cam 14. The third intake rocker arm 19 is provided with both intake valves 5a and 5b without opening and closing the intake valves. A free rocker arm that can be free for 5a and 5b. Similarly, the third and fourth exhaust rocker arms
Each of 23 and 24 is a free rocker arm that can be free with respect to the exhaust valves 6a and 6b without opening and closing the exhaust valves 6a and 6b. Further, the one end of the third intake rocker arm 19 is located above the camshaft 13 and the first exhaust rocker arm 21.
Is located adjacent to the one end of the second exhaust rocker arm 22 along the camshaft 13 in parallel.

In the cylinder head 1, an upper end surface opposite to the coupling surface with the cylinder block with respect to the cam shaft 13 is provided on an upper end surface in the cylinder arrangement direction of three cylinders A1, A2, and A3.
That is, in the axial direction L of the camshaft 13, from one end to the other end of the cylinder head 1, the plate-shaped holder 50 shown in FIG. 1
See).

In this holder 50, the first and second intake rocker arms 17, 18 for the cylinders A1, A2, A3 are respectively attached to the valve stem ends of the intake valves 5a, 5b via tappet screws 26. The first and second lost motion mechanisms 31 and 32 as urging members for urging toward the intake cam 14 toward the intake cam 14 as urging members. The third lost motion mechanism 33 and the third and fourth exhaust rocker arms 23 and 24 are respectively connected to both exhaust cams 16.
Fourth and fifth lost motion mechanisms 34 and 35 as urging members for urging toward a and 16b by resilient force are formed with first to fifth holding parts 51 to 55 which are respectively mounted and held. Is done. Further, fastening portions C1 to C10 formed of cylindrical bosses having bolt insertion holes are formed in the holder 50 corresponding to the bolts B1 to B10.

Referring to FIG. 4, first and second holding portions 51,
The bottom 52 has bottomed holes 51a and 52a, and has open ends 51b and 52b opened on the rocker arm side 50a where the rocker arms 17 to 19 and 21 to 24 are disposed with respect to the holder 50. Is a bottomed holding portion having a partially cylindrical shape and protrudes from the holder 50 on the opposite rocker arm side 50b opposite to the rocker arm side 50a.

The first and second lost motion mechanisms 31, 32 attached to the bottomed holes 51a, 52a respectively have the same structure, and are slidably fitted to the bottomed holes 51a, 52a, respectively. A cylindrical piston 36 having a top surface, and the top surface of the piston 36 abuts on contact surfaces 17a, 18a formed on the upper portions of the first and second intake rocker arms 17, 18, so that the two intake rocker arms 17,
A cylindrical coil spring as a resilient member mounted between the piston 36 and the bottom surface of each of the holding portions 51 and 52 so as to urge the 18 toward the intake valves 5a and 5b by their resilient force. 37
And retaining rings 38 detachably mounted in grooves near the open ends 51b, 52b on the inner surfaces of the holding portions 51, 52.

Further, referring to FIG. 3, the third holding portion 53
Has a through hole 53a that penetrates from the rocker arm side 50a of the holder 50 to the anti-rocker arm side 50b and faces the third intake rocker arm 19, and has a first opening end 53b opened to the rocker arm side 50a and an anti-rocker arm side 50b. A partially cylindrical cylindrical penetrating holding portion having the second opening end 53c described above, and protruding from the holder 50 on the anti-rocker arm side 50b.

The third lost motion mechanism 3 attached to the through hole 53a from the side 50b opposite to the rocker arm 50b of the holder 50.
Reference numeral 3 denotes a contact piece that is located near the first opening end 53b and contacts a contact surface 19a formed on the upper part of the third intake rocker arm 19.
1, a fixing piece 42 screwed into a screw portion 53d formed near the second opening end 53c inside the third holding portion 53, and the third suction rocker arm 19 is connected to the suction cam 14 via a contact piece 41. And a cylindrical coil spring 43 as a resilient member held between the fixed piece 42 and the contact piece 41 so as to be urged by the resilient force toward the spring. The outer periphery of the coil spring 43 is in contact with the inner peripheral surface of the third holding portion, and guides the coil spring 43 along the through hole 53a to prevent the coil spring 43 from falling down.

The contact piece 41 includes a collar-shaped retainer 41a that contacts one end of the coil spring 43, and a column-shaped fitting portion 41b that is fitted and held on the inner periphery of the coil spring 43. Further, the fixing piece 42 is in contact with the other end of the coil spring 43, and a retainer portion 42a having a threaded portion 42d formed on the outer peripheral surface thereof, and a cylindrical fitting fitted and held on the inner periphery of the coil spring 43. Joint 42b,
And a flange portion 42c abutting on the second open end 53c. Further, in order to attach the third lost motion mechanism 33 to the third holding portion 53, the screw portion 42d of the fixing piece 42 and the screw portion 53d of the third holding portion 53 are screwed to the fixing piece 42, A hexagonal hole 42e, which is a tool insertion hole into which a tool for screwing the fixing piece 42 is inserted, is formed, and a fitting portion 42e is formed at the bottom of the hexagonal hole 42e.
Is formed. The upper end of the oil supply hole 42f is open toward the space above the valve operating chamber,
The lower end is open to the end face of the fitting portion 42b on the contact piece 41 side. Therefore, in the space, the droplets of the lubricating oil supplied to the sliding portion of the valve gear, etc., directly from the oil supply hole 42f,
Alternatively, it is supplied to the contact piece 41 and the coil spring 43 of the third lost motion mechanism 33 through the oil supply hole 42f as a liquid flow by adhering to the fixed piece 42, and the sliding parts thereof are lubricated.

On the other hand, as shown in FIG. 5, the fourth and fifth holding parts 54, which hold the fourth and fifth lost motion mechanisms 34, 35 having the same structure as the third lost motion mechanism 33, respectively. 55 has the same structure as the third holding portion 53. Then, the contact pieces 41 of the fourth and fifth lost motion mechanisms 34 and 35
Are in contact with contact surfaces 23a and 24a (see FIG. 1) formed on the upper portions of the third and fourth exhaust rocker arms 23 and 24, respectively. The first to fifth holding parts 51 to 55 are held in such a manner that they are inclined with respect to the coupling surface between the cylinder block and the cylinder head 1, ie, the center lines of the cylinders of the first to fifth holding parts are inclined. 50 is provided.

As shown in FIG. 6, the first connection switching mechanism M1 provided on the first, second, and third intake rocker arms 17, 18, 19 includes a piston 60, first and third intake rocker arms. A connecting pin 61 for connecting the intake rocker arms 17 and 19, and a connecting piston 62 for restricting movement of the piston 60 and the connecting pin 61 and connecting the second and third intake rocker arms 18 and 19;
And a return spring 63 for urging the piston 60 and the connecting pin 61 toward the connecting side.

The first intake rocker arm 17 has a piston 60
And a guide hole with a bottom in which the connecting pin 61 is slidably fitted
A hydraulic chamber 64 is formed with its open end facing the third intake rocker arm 19 and between the piston 60 and the bottom of the guide hole 64.
67 is formed. Further, the hydraulic chamber 67 communicates with a hydraulic supply passage 69 (FIG. 4) inside the intake rocker arm shaft 20 via a communication passage 68.
) And the first intake rocker arm 17 regardless of the swinging state. A guide hole 65 having the same diameter is formed in the third intake rocker arm 19 at a position corresponding to the guide hole 64 with both open ends thereof facing the first and second intake rocker arms 17 and 18, respectively. The connecting pin 61 and the connecting piston 62 are slidably fitted on the connecting pin 61 and the connecting piston 62. A guide hole 66 having the same diameter and a bottom is formed in the second intake rocker arm 18 at a position corresponding to the guide hole 65 with its open end facing the third intake rocker arm 19. Are slidably fitted. The return spring 63 is mounted on the inner periphery of the connecting piston 62 in a compressed state between the bottom of the guide hole 66 and the connecting piston 62.

The hydraulic pressure in the hydraulic pressure supply passage 69 controlled by the hydraulic pressure control valve causes the hydraulic pressure chamber 67 of the first connection switching mechanism M1 to operate.
When the hydraulic pressure is low, the piston 60, the connecting pin 61, and the connecting piston 62 move toward the connecting side by the elastic force of the return spring 63, and the connecting pin 61 is fitted across the two guide holes 64, 65. At the same time, the connecting piston 62 is fitted over the two guide holes 65 and 66, and the first, second, and third intake rocker arms 17, 18, and
19 is in a connected state of being integrally connected. When the hydraulic pressure in the hydraulic chamber 67 is increased by the hydraulic control valve, the piston 60 moves to a position where the connecting pin 61 is pushed into the third intake rocker arm 19, and the contact surface between the piston 60 and the connecting pin 61 is moved. Are located between the first and third intake rocker arms 17 and 19, and the contact surface between the connecting pin 61 and the connecting piston 62 is located between the second and third intake rocker arms 18 and 19, so that the first , The second and third intake rocker arms 17, 18, and 19 are in a disconnected state in which they are not connected.

On the other hand, the first and third exhaust rocker arms 21 and 23
As shown in FIG. 7, the second connection switching mechanism M2 is provided with a piston 70 and the first and third exhaust rocker arms 2.
A connecting pin 71 for connecting the first and the second 23, a regulating piston 72 for regulating the movement of the piston 70 and the connecting pin 71, and a piston
70, a connecting pin 71 and a return spring 73 for urging the regulating piston 72 toward the connecting side. The first exhaust rocker arm 21 has a bottomed mounting hole 21a into which the inner ring 29a of the roller 29 is press-fitted and fixed.
Is formed with its open end facing the third exhaust rocker arm 23, and a piston 70 is formed in a guide hole 74 formed in the inner race 29a.
And the connecting pin 71 are slidably fitted. The hydraulic chamber 7 formed between the piston 70 and the bottom of the bottomed mounting hole 21a
6 always communicates with the hydraulic supply path 78 (see FIG. 4) inside the exhaust rocker arm shaft 25 via the communication path 77 regardless of the swing state of the first exhaust rocker arm 21. In the third exhaust rocker arm 23, a bottomed mounting hole 23b into which the inner race 30a of the roller 30 is press-fitted and fixed is formed with its open end facing the first exhaust rocker arm 21, and a guide hole 74 is formed in the inner race 30a.
The connecting pin 71 and the restricting piston 72 are slidably fitted in the guide holes 75 having the same diameter formed at positions corresponding to the positions. The return spring 73 is located inside the regulating piston 72 and has a bottomed mounting hole 23b.
It is mounted in a compressed state between the bottom of the piston and the regulating piston 72.

The hydraulic pressure in the hydraulic supply passage 78 controlled by the hydraulic control valve causes the hydraulic chamber 76 of the second connection switching mechanism M2 to operate.
When the hydraulic pressure is lowered, the piston 70, the connecting pin 71, and the regulating piston 72 move toward the connecting side by the elastic force of the return spring 73, and the connecting pin 71 fits across the guide holes 74 and 75. As a result, the first and third exhaust rocker arms 21 and 23 are connected to be integrally connected. In addition, the hydraulic chamber 76 is controlled by the hydraulic control valve.
When the hydraulic pressure is increased, the piston 70 moves to a position where the connecting pin 71 is pushed into the third exhaust rocker arm 23, and the contact surface between the piston 70 and the connecting pin 71 is moved to the first and third exhaust rocker arms 21,. 23, the first and third exhaust rocker arms 21 and 23 are in a disconnected state in which they are not connected.

The second and fourth exhaust rocker arms 22, 24
Also provided is a second connection switching mechanism M2 having the same structure as the second connection switching mechanism M2 provided on the first and third exhaust rocker arms 21 and 23, and when the hydraulic pressure in the hydraulic chamber 76 is low,
The piston 70, the connecting pin 71, and the regulating piston 72 are moved toward the connecting side by the resilience of the return spring 73, and the connecting pin 71 is fitted over the guide holes 74 and 75 to form the second and fourth exhaust ports. The rocker arms 22 and 24 are in a connected state of being integrally connected. When the hydraulic pressure in the hydraulic chamber 76 becomes high, the piston 70 moves to a position where the connecting pin 71 is pushed into the fourth exhaust rocker arm 24,
Since the contact surface between the piston 70 and the connecting pin 71 is located between the second and fourth exhaust rocker arms 22 and 24, the second and fourth exhaust rocker arms 22 and 24 are in a disconnected state where they are not connected.

Here, the cam shaft 13 provided with the cam, the rocker arms 17 to 19 and 21 to 24, the rocker arm shafts 20 and 25, the intake valves 5a and 5b, the exhaust valves 6a and 6b, the holder 50, A valve train is constituted by members attached thereto.

Next, referring to FIGS. 1 and 2, the holding portions 51, 52, 53, 5 projecting from the side 50b opposite to the rocker arm 50b.
The holder 50 in which 4, 55, the fastening portions C1 to C10, and the reinforcing ribs are integrally formed by casting will be further described. In the cylinder A1, the side surfaces of the first and second holding portions 51 and 52 are directly connected to both side surfaces in the axial direction L of the cam shaft 13 of the third holding portion 53.

The third holding portion 53 is located on the side opposite to the side where the second opening end 53c is located with respect to the axis of the cam shaft 13 and passes through the center line of the cylinder of the third holding portion 53. The fourth and fifth holding parts 54 and 55 are arranged so that the second opening ends 54c and 55c are located substantially symmetrically with respect to a plane P orthogonal to the axis.
Between 55, the upper portions of the first and second exhaust rocker arms 21 and 22 are inserted into the concave portion 56 formed by lightening. The arrangement of the first to fifth holding parts 51, 52, 53, 54, 55 in the holder 50 is the same for the remaining two cylinders A2, A3. Further, a pipe 39 into which an ignition plug is inserted is disposed between the first and second exhaust rocker arms 21 and 22 and near an end where the tappet screws 27 and 27 are provided.

Further, fastening parts C1 to C10 to which bolts B1 to B10 for fastening the holder 50 to the cylinder head 1 are inserted and fastened are inserted.
10 are arranged as follows. Of the three cylinders A1, A2, A3 arranged in a line, the cylinder A1 located at one end is closest to one end of the holder 50 among the holding portions 51, 52, 53, 54, 55 of the cylinder A1. On the side of the located fourth holding portion 54 near the one end of the holder 50 in the axial direction L of the camshaft 13, the fastening portion C1 is a position where the side surface thereof is directly connected to the side surface of the fourth holding portion 54. Is provided.

In the first and second holding parts 51 and 52,
Two fastening portions C2 and C3 are provided on the side opposite to the side where the third holding portion 53 is located in the axial direction L of the camshaft 13, respectively. Fourth ribs 84, 84 connect the side surfaces of the portions C2, C3, respectively.

Further, on the side of the fifth holding portion 55 located closest to the cylinder A2 among the holding portions 51 to 55 of the cylinder A1 and closer to the cylinder A2 in the axial direction L of the camshaft 13, a fastening portion C4 is provided. It is provided at a position where the side surface and the side surface of the fifth holding portion 55 are directly connected. Further, in the fastening portion C4, the side surface on the side opposite to the side where the fifth holding portion 55 is located in the axial direction L of the camshaft 13 is located closest to the cylinder A1 in the holding portions 51 to 55 of the cylinder A2. 4 is directly connected to the side surface of the holding portion 54.

The cylinders A2 and A3 have the same arrangement of the holding parts 51 to 55 and the fastening parts C4 to C7 as the cylinder A1. That is, in the cylinder A2, the fastening portion C4 is located at a position directly connected to the side surface of the fourth holding portion 54 on the side of the fourth holding portion 54 near the cylinder A1 in the axial direction L of the camshaft 13 as described above. Is provided. In the first and second holding portions 51 and 52, two fastening portions provided on the side of the cam shaft 13 in the axial direction L.
The side surfaces of C5 and C6 are connected by fourth ribs 84 provided between the side surfaces of the first and second holding portions 51 and 52, respectively. Further, the fastening portion C7 whose side surface is directly connected to the side surface of the fourth holding portion 54 in the cylinder A3 is connected to the cylinder A3 in the axial direction L of the cam shaft 13.
The side opposite to the side where the fourth holding part 54 is located is provided at a position directly connected to the side of the fifth holding part 55 located closest to the cylinder A3 among the holding parts 51 to 55 of the cylinder A2. Can be

Similarly, in the cylinder A3, the fastening portion C7 is
In the axial direction L of the camshaft 13 of the holding portion 54, on the side near the cylinder A2,
It is provided at a position directly connected to the side surface of the fourth holding portion 54. In the first and second holding portions 51 and 52, the camshaft 13
Two fastening portions C8, C9 provided on the side in the axial direction L of
Are connected by fourth ribs 84, 84 provided between the side surfaces of the first and second holding portions 51, 52. Furthermore, the fastening part C1
0 is the cam shaft of the fifth holding portion 55 whose side face is located closest to the other end of the holder 50 among the holding portions 51 to 55 of the cylinder A3.
13 is provided at a position directly connected to the side surface of the fifth holding portion 55 on the side near the other end of the holder 50 in the axial direction L.

Then, of the fastening portions C1 to C10, the cam shaft 13 is adjacent to the cam shaft 13 on the side where the first, second, and third holding portions 51, 52, and 53 are directly connected to each other. cylinder
The ends of the holders 50 of the joints C2 and C9 located between the joints C3 and C5 between A1 and A2, between the joints C6 and C8 between the cylinders A2 and A3, and at the ends of the cylinders A1 and A3 at both ends. A concave portion 57 is formed near the portion by lightening, and a coupling member for coupling the cylinder head 1 to the cylinder block, for example, an insertion hole through which a bolt is inserted, is formed in the cylinder head 1 corresponding to the position of the concave portion 57. 58 are formed. The joints C3, C5, C6, and C8 between the adjacent cylinders have cutouts 59 at their opposing sides so that the coupling member does not interfere with the joints C3, C5, C6, and C8. Are provided, and the fastening portions C2 and C9, which are located near both ends, have similar cutouts near the ends.
59 are provided.

The first and second lost motion mechanisms 3
1 and 32, when both intake valves 5a and 5b are closed, and in the third, fourth and fifth lost motion mechanisms 33 to 35, the third intake rocker arm 19 is operated by the intake cam 14 or the exhaust cams 16a and 16b. Or the third and fourth exhaust rocker arms 23,
When the 24 swings, the spring force due to the compression of the coil spring 37 or the coil spring 43 acts on the holding portions 51 to 55. Therefore,
The holder 50 is provided with a plurality of ribs for increasing its rigidity in order to oppose the load acting on the holder 50 and to suppress the generation of vibration due to the operation of the valve train. Among these ribs, the first rib 81 is connected to the side surface of the cam shaft 13 in the axial direction L at substantially the center position of the length of the third holding portion 53 of each cylinder A1, A2, A3 in the center line direction. , And extend linearly along the axial direction L of the camshaft 13.

Further, in each of the cylinders A1, A2, A3, the second rib 82 is connected to the center line of the fourth holding portion 54, 54, 54 and the fastening portion C.
A rib 82a extending linearly so as to connect the two sides along a plane including the center lines of C5, C8, and fifth holding portions 55, 5;
The ribs 82b extend linearly so as to connect the two side surfaces along a plane including the center lines of 5, 55 and the center lines of the fastening portions C3, C6, C9. The second rib 82 is connected to the fourth and fifth holding portions 54 and 55 and the fastening portions C2, C5 and C5.
8, C3, C6, C9, so as to intersect with the first rib 81,
In this embodiment, they extend substantially orthogonally, and are connected to the first rib 81 at the intersection.

In the cylinder A1, the third rib 83 is connected to the connecting portion D of the third holding portion 53 with the first rib 81, the side surface of the fastening portion C1 directly connected to the side surface of the fourth holding portion 54, and the fourth portion. 5 Holder 55
And extends linearly so as to connect the side surface of the fastening portion C4 directly connected to the side surface thereof. Further, the third rib 83 is a cylinder
A2 and A3 are the same as the cylinder A1, and the cylinder A2 has a connection portion D with the first rib 81 of the third holding portion 53 and a fastening portion.
It extends linearly to connect the side surface of C4 and the side surface of the fastening portion C7. For the cylinder A3, the connection portion D of the third holding portion 53 to the first rib 81, the side surface of the fastening portion C7 and the fastening Part C10
It extends linearly to connect to the side surface. These third ribs 83 are formed by the second rib 82 and the fourth and fifth holding portions 54,
They intersect near 55 and are connected to the second rib 82 at the intersection.

In the valve train configured as described above,
When the internal combustion engine is operated, during normal operation in which the cylinder deactivation operation is not performed, the hydraulic pressure chamber 67 of the first connection switching mechanism M1 is set to a low pressure, so that the first, second, and third intake rocker arms 17, 18, and 19 are operated. Are in a connected state, and the first and second intake rockers 19 are in contact with the pair of intake valves 5a and 5b by the intake cam 14 in sliding contact therewith.
The second intake rocker arms 17 and 18 are the third intake rocker arms 19
Therefore, the two intake valves 5a and 5b are opened and closed by a valve opening characteristic determined by the intake cam 14. therefore,
The first and second intake rocker arms 17 and 18 are indirectly oscillated by the two intake cams 14, respectively.
Is linked with the intake valves 5a and 5b.

On the other hand, at this time, the two second connection switching mechanisms M2,
Since the pressure in the hydraulic chamber 76 of M2 is low, the first and third exhaust rocker arms 21 and 23 and the second and fourth exhaust rocker arms 2
Exhaust cams 16a and 16b are connected to each other, and the third and fourth exhaust rocker arms 23 and 24 are in sliding contact with each other.
Accordingly, the first exhaust rocker arm 21 in contact with the exhaust valve 6a swings integrally with the third exhaust rocker arm 23, and the second exhaust rocker arm 22 in contact with the exhaust valve 6b swings integrally with the fourth exhaust rocker arm 24. The exhaust valves 6a, 6b are opened and closed with valve opening characteristics determined by the exhaust cams 16a, 16b, respectively. Therefore, the first and second exhaust rocker arms 21 and 22
Are rocked indirectly by the two exhaust cams 16a, 16b, respectively, and the third and fourth exhaust rocker arms 23, 24
Works with a and 6b respectively.

During the cylinder deactivated operation in which the internal combustion engine is operated in an engine operation range that emphasizes fuel efficiency such as a low load operation range, the hydraulic chamber 67 of the first connection switching mechanism M1 is at a high pressure. , The third intake rocker arms 17, 18, and 19 are in a disconnected state, and the pair of intake valves 5a and 5b are connected to the third intake rocker arms 19 and 18.
Since the valve opening force of the intake cam 14 is not transmitted through the intake cam 14, the intake valves 5a and 5b are normally closed.

The first and second intake rocker arms 17,
Reference numeral 18 always maintains an appropriate valve clearance even during the cylinder deactivated operation by the elastic force of the coil spring 37 of the first and second lost motion mechanisms 31, 32. Also, the third
Although the intake rocker arm 19 is urged to slide on the intake cam 14 by the resilient force of the coil spring 43 of the third lost motion mechanism 33, it moves idly, but the coil spring 43 of the third lost motion mechanism 33 moves. By expanding and contracting, the third intake rocker arm 19 is prevented from ramping up.

The hydraulic chambers of the two second connection switching mechanisms M2, M2
Since 76 is set to high pressure, the first and third exhaust rocker arms 2
1, 23, and the second and fourth exhaust rocker arms 22, 24,
The third and fourth exhaust rocker arms 23 and 24 are in the disconnected state, and the paused exhaust cams 16a and 16b that are in sliding contact with each other.
As a result, the valve is normally closed. The third and fourth exhaust rocker arms 23 and 24 are urged to slide on the exhaust cams 16a and 16b by the elastic force of the coil springs 43 of the fourth and fifth lost motion mechanisms 34 and 35, respectively. Thus, the coil spring 43 of the fourth and fifth lost motion mechanisms 34 and 35 expands and contracts, thereby preventing the third and fourth exhaust rocker arms 23 and 24 from running out.

The operation and effect of the embodiment configured as described above will be described below. Since the first, second, and third holding portions 51, 52, and 53 holding the first, second, and third lost motion mechanisms 31, 32, and 33, respectively, are directly connected and integrated, the holding portions are provided. Since the reinforcements 51 to 53 reinforce each other, the rigidity between the holding portions 51 to 53 is increased. As a result, the deformation between the holding portions 51 to 53 can be suppressed, and the trouble of each lost motion mechanism 31 to 33 occurs. For example, the resilient force becomes weaker than the set resilient force of the coil springs 37, 43, the action direction of the resilient force deviates from the set direction, or the piston 36 and the first and second holding portions 51, 52 The sliding motion of the sliding portion with the inner peripheral surface of the coil spring 43 and the sliding portion of the coil spring 43 with the inner peripheral surface of the third holding portion 53 is prevented from being performed smoothly.

By using the mutual holding parts 51 to 53 themselves, the rigidity between the holding parts 51 to 53 can be increased without additionally forming a new reinforcing structure on the holder 50.
An increase in the weight of the holder 50 can be suppressed. Further, since the holding portions 51 to 53 are directly connected and integrated in a state where the holding portions 51 to 53 are juxtaposed in the axial direction L of the camshaft 13, the width of the juxtaposed holding portions 51 to 53 in the axial direction L of the camshaft 13 is reduced. Can be made small, three holding parts 51-53
Can be arranged compactly, and the size of the internal combustion engine in the cylinder arrangement direction can be reduced.

Further, the first and the first components which are directly connected and integrated
The second and third holding portions 51, 52 and 53 are a first holding portion 51 and a second holding portion 52 which are bottomed holding portions and a third holding portion 53 which is a through holding portion.
Combination of As a result, the integrated holding portions 51, 52, 53 are not the through holes but the bottomed first and second holding portions.
51, 52, the first, second, and third holding portions 51, 5
The rigidity between the cylinder heads 2 and 53 can be increased, and at the same time, after the holder 50 is attached to the cylinder head 1, the through holes 53a
By using the rocker arms 17 to
The third lost motion mechanism 33 can be mounted on the third holding portion 53 from the second opening end 53c which is open to the anti-rocker arm side 50b on the side without the valve operating mechanism such as 19, 21 to 24, etc. Can be easily mounted, and the workability of assembling the lost motion mechanism can be improved.

The first, second, and second holding parts are directly connected to each other.
The third holding portions 51, 52, 53 are connected to the first and second ribs 81, 82 and the third and fourth ribs 83, 84 connected to the fastening portions C1 to C10, and the fourth and fifth holding portions 54 are provided. , 55 are fastening parts C1, C4, C7,
Bolts B1, B4, B7, B10 inserted into C10 and fastening part C
2, C3, C5, C6, C8, C9 connected second and third ribs 82,
Since the holder 50 is connected, the rigidity of the entire holder 50 is increased, the operation of the valve train is stabilized, and vibration is suppressed, and noise is reduced.

Each of the fourth and fifth holding portions 54 and 55 has a fastening portion C which is connected to the cylinder head 1 in the holder 50.
1, C4, C7, and C10 are directly connected and integrated, so the rigidity between the holding portions 54 and 55 is increased,
Deformation between the holding portions 54 and 55 can be suppressed, and occurrence of troubles of the fourth and fifth lost motion mechanisms 34 and 35 can be suppressed.
Also, the fastening parts C1, C4, C7, C10 where the holding parts 54, 55 are located
Is high rigidity, the holder 50 by a load acting via the fourth and fifth lost motion mechanisms 34 and 35 based on the swinging of the third and fourth exhaust rocker arms 23 and 24.
The overall deformation can be suppressed.

The holder 50 has first ribs 81 extending along the axial direction L of the camshaft 13 and connecting the third holding portions 53 of the cylinders A1, A2, A3 to each other, and fourth and fifth holding portions. 54, 55 and fastening part C2,
Second ribs 82 are provided to connect C3, C5, C6, C8, and C9, respectively. The second ribs 82 are provided between the fourth holding portion 54 and the fastening portions C2, C5, and C8, and the second rib 82. 5 Holding part 55 and fastening part C3,
The first rib 81 is connected between C6 and C9. As a result, the first rib 81 and the second rib 82 are intersected with each other, so that the rigidity of the entire holder 50 is increased, so that the occurrence of troubles of the lost motion mechanisms 31 to 35 is further suppressed, and The operation of the valve gear is stabilized, and furthermore, vibration is suppressed and noise is reduced. Further, as in the embodiment,
When the first rib 81 and the second rib 82 intersect substantially orthogonally, the rigidity is further increased.

The holder 50 has a concave portion 56 formed between the fourth and fifth holding portions 54 and 55, and further, between the fastening portions C3 and C5,
Since the concave portions 57 are formed between C6 and C8 and near the ends of the fastening portions C2 and C9 located at both ends, the weight of the holder 50 can be reduced, and the weight of the internal combustion engine can be reduced.

The first to fifth holding parts 51 to 55 are provided on the holder 50 so as to be inclined with respect to the connecting surface between the cylinder block and the cylinder head 1. , 55, the upper portions of the first and second exhaust rocker arms 21, 22 are inserted into the concave portion 56, thereby reducing the axial dimension of the cylinder of the internal combustion engine.
The internal combustion engine can be made compact.

Hereinafter, an embodiment in which a part of the configuration of the above-described embodiment is changed will be described with respect to the changed configuration. In the above embodiment, the first, second, and third holding portions 51, 5
The two holding parts 2, 53 are directly connected to each other, but the number of holding parts directly connected to each other may be two or more. In the above-described embodiment, the valve train is a valve train that performs cylinder deactivation.However, without performing cylinder deactivation, the intake valve and the exhaust valve are constantly opened and closed during engine operation, and the valve operation is performed according to the engine operation state. The valve operating device may be provided with a mechanism for changing valve operating characteristics such as a lift amount.

[Brief description of the drawings]

FIG. 1 is a plan view of a main part of a three-cylinder cylinder head forming one bank of an internal combustion engine to which the present invention is applied.

FIG. 2 is a plan view of a holder.

FIG. 3 is a sectional view taken along line III-III of FIG. 1;

FIG. 4 is a sectional view taken along line IV-IV of FIG. 1;

FIG. 5 is a sectional view taken along line VV of FIG. 1;

FIG. 6 is a sectional view taken along line VI-VI of FIG. 4;

FIG. 7 is a sectional view taken along line VII-VII of FIG. 4;

[Explanation of symbols]

1 ... cylinder head, 2 ... combustion chamber, 3 ... intake port, 4
… Exhaust port, 5a, 5b… Intake valve, 6a, 6b… Exhaust valve, 7,
8 ... Stem guide, 9,10 ... Flange, 11,12 ... Valve spring, 13
… Cam shaft, 14… Intake cam, 15a, 15b… Exhaust stop cam, 1
6a, 16b ... exhaust cam, 17, 18, 19 ... intake rocker arm, 2
0 ... intake rocker arm shaft, 21, 22, 23, 24 ... exhaust rocker arm, 25 ... exhaust rocker arm shaft, 26, 27 ... tappet screw, 28 ... roller, 29, 30 ... roller, 31-35 ... lost motion mechanism, 36 ... Piston, 37 ... Coil spring, 38 ... Retaining ring, 39 ... Pipe, 41 ... Abutment piece, 42 ... Fixed piece, 43 ... Coil spring, 50 ... Holder, 51-55 ... Holding part, 51a, 52a ... Bottom hole 53a: through-hole, 53c: second open end, 56, 57: recess, 58
... insertion hole, 59 ... notch, 60 ... piston, 61 ... connecting pin,
62 ... connecting piston, 63 ... return spring, 64, 65, 66 ... guide hole, 67 ... hydraulic chamber, 68 ... communication passage, 69 ... hydraulic supply path, 70 ... piston, 71 ... connecting pin, 72 ... regulating piston, 73 … Return spring, 74, 75… Guide hole, 76… Hydraulic chamber, 77… Communication passage, 78…
Hydraulic pressure supply path, 81: first rib, 82: second rib, 84: third rib, 84: fourth rib, A1, A2, A3: cylinder, B1 to B10: bolt, C1 to C10: fastening portion, D ... Connection portion, L: axial direction of cam shaft, M1, M2: connection switching mechanism, P: plane.

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) DA09 DA17 DA19 FA01 FA13

Claims (4)

[Claims] A plurality of rocker arms, which are swingable directly or indirectly by a cam provided on a camshaft and are interlocked with an engine valve, are respectively biased toward the engine valve or the cam by a resilient force. And a holder provided with a plurality of holding portions attached to the engine body and holding the respective biasing members, wherein at least two of the holding portions are A valve train for an internal combustion engine, which is directly connected and integrated. 2. The at least two holding portions directly connected to each other have a bottomed hole and a bottomed holding portion having an open end opened to the rocker arm side of the holder, and a through hole penetrating the holder. And a through-holding portion having a first open end that opens to the rocker arm side and a second open end that opens to the opposite rocker arm side of the holder,
A part of the urging member is held in the bottomed hole of the bottomed holding part, and the through hole of the through holding part is attached to the through hole from the second opening end of the urging member. The biasing member formed so as to be held is held.
A valve gear for an internal combustion engine according to the above. 3. A plurality of rocker arms, which are directly or indirectly swung by a cam provided on a camshaft and are capable of interlocking with an engine valve, for urging the rocker arms toward the engine valve or the cam by resilient force. And a holder provided on the engine main body and provided with a plurality of holding portions respectively holding the biasing members, wherein at least two of the holding portions are A valve gear for an internal combustion engine, wherein each holding portion is directly connected to a fastening portion of the holder for attaching the holder to the engine body, and integrally connected via the fastening portion. 4. The holder has a first rib extending in the axial direction of the camshaft and connecting the holding portions to each other, and the holding portion separate from the holding portion connected to the first rib. And a second rib connecting a fastening portion of the holder for attaching the holder to the engine body.
The internal combustion engine according to any one of claims 1 to 3, wherein the second rib is connected to the first rib between the connected holding part and the fastening part. Engine valve gear.