JPS6270610A - Tappet device with stopping function of internal combustion enginee - Google Patents

Abstract

PURPOSE:To reduce the number of parts and to achieve cost reduction by operating a changeover valve for changing over a control mechanism driving system by means of a centrifugal governor so as to perform the changeover of a valve operation and stoppage by a mechanical means, in a SOHC type internal- conmbustion engine. CONSTITUTION:When the revolutions of an engine reach a prescribed value, the weight 36b of a centrifugal governor 36 moves outward to turn a governor shaft 35 in a prescribed angle, and the longitudinal grooves 38 on a governor shaft 35 is communicated with holes 34 and 41 formed on a cam shaft 3. Accordingly, the oil pressure supplied from a main pump is supplied to oil passages 44 via circumferential grooves 33, 37, 38, 42 and holes 34, 41, and further is supplied to oil chambers 28 through oil passages 30, 29 inside rocker shafts 8, 9. Consequently, changeover type rocker arms 11, 13 are turned integrally with steady moving type rocker arms 10, 12 which are turned rockedly by cams 3a and 3b, so that all intake and exhaust valves are driven.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a valve train with a shutdown function for an internal combustion engine, which has a shutdown function that suspends operation of an intake or exhaust valve depending on the rotational speed of the engine. It is.

``Prior Art'' As one type of valve train with a bipedal locking function, a rocker arm that moves following the rotation of the camshaft and presses the valve stem end with its tip acting part is used to prevent the camshaft from moving during operation. It is divided into two parts: a part that constantly oscillates due to rotation, and a part that presses the valve stem end, and these parts are interlocked with each other via a pin, or by removing the pin, the interlocking of the part is released. There is a structure in which a desired intake valve or exhaust valve is prevented from being driven or stopped depending on the rotational status of the engine.

The conventional means of switching between valve operation and valve rest as described above is to electrically detect the operating state such as the engine rotation speed using a detection device, and operate a switching valve using a solenoid to control the supply of oil to the hydraulic chamber. The switching was done by electrical control.

``Problems to be solved by the invention j Valve operation/valve body l by electrical control as described above
The two-switching means requires a detection device, a solenoid valve, etc., which increases the cost, and requires a large number of parts. Therefore, it is conceivable to control the switching mechanically, but unlike electrical means, there are many restrictions on where it can be installed, and practical methods are difficult to implement. It has not been done.

``Object of the Invention J In view of the above-mentioned problems such as cost and number of parts in electrical control means, the present invention has been developed to provide a valve body JJ that does not have these problems, especially in an SOI (C type internal combustion engine). The purpose of this invention is to realize a mechanical switching control means in which the AJ+ passage of the two switching controller tI is short and the same oil passage can be secured with a simple configuration.

"Means for Solving the Problems" In order to achieve the above object, the present invention provides a hydraulic operating system for a valve operation/pause switching control mechanism that is connected to a pressure oil supply source.
a switching valve operated by a centrifugal governor that communicates with the pressure oil supply source and is incorporated inside the camshaft; an oil passage that communicates with the switching valve and is formed within the former rocker; an rd+ passage connecting the passage and the operating system of the control mechanism; the plurality of discharge holes of the switching valve are provided on the same plane perpendicular to the axis of the camshaft, and support the camshaft of the cylinder head; A circumferential groove is provided in the bearing section surrounding the discharge hole of the switching valve, and the circumferential groove and the oil passage in the rocker shaft are linear from the camshaft bearing section of the cylinder head to the rocker shaft bearing section. The structure is such that they are communicated with each other by an oil passage extending between the two.

``Operation'' In the high speed rotation range of the engine, the switching valve connected to the centrifugal governor that rotates together with the camshaft is in an open state, and the pressure Ah from the pressure Ah supply source is transferred to the switching valve built into the camshaft. From there, through an oil passage extending from the camshaft bearing of the cylinder head to the rocker shaft bearing, and an oil passage within the rocker shaft, the oil is guided to the control mechanism drive system within the rocker arm,
A rocker arm that can be switched between activation and deactivation is placed in a valve operable state, and an intake valve or an exhaust valve is driven by a cam via the rocker arm.

When the rotation speed decreases and reaches a predetermined rotation range, the centrifugal cabana turns off the switching valve, pressure oil from the pressure oil supply source is not supplied to the control mechanism drive system in the rocker arm, and the rocker arm enters the valve rest state. , the rotation of the cam is not transmitted to the intake or exhaust valves.

"Example" Hereinafter, an example of the present invention will be described in FIGS. 1 to 6 (A),
This will be explained with reference to (b).

In this embodiment, the present invention is arranged so that one of the two intake valves and one of the two exhaust valves can be switched between an operating state and a rest state, and furthermore, The valves that switch between the active state and the rest state are arranged so that they cross each other when viewed from above.

Fig. 1 is a view of the engine with the cylinder cover removed from above, Fig. 2 is a sectional view taken along the line ■-■ in Fig. 1, and Fig. 3 is a cross-sectional view taken along the line ■-■ in Fig. 1. ) is a cross-sectional view.

In these figures, reference numeral 1 denotes a cylinder head, and 2 a cylinder head cover (see FIGS. 2 and 3). A camshaft 3 is rotatably supported on the cylinder head 1.

The camshaft 3 rotates in conjunction with the rotation of a crankshaft (not shown) via a sprocket 4 and a chain 5 screwed to the camshaft 3.

This engine has two intake valves 6 and two exhaust valves 7, and the camshaft 3 has cams 3a and 3m corresponding to the intake valves 6 and exhaust valves 7, respectively, and a rocker shaft on the exhaust side. 9 are supported by the cylinder head 1 and are provided parallel to the camshaft 3 and located on both sides of the camshaft 3. On the intake side rocker shaft 8, a permanent type rocker arm 10 and a switching type rocker arm II are each swingably supported, while on the exhaust side rocker shaft 9, a permanent type rocker arm 12 and a switching type rocker arm I3 are respectively supported. It is supported so that it can swing freely.

Furthermore, as described above, in this engine, the full-time rocker arm IO on the intake side and the full-time rocker arm 12 on the exhaust side
are arranged so that they cross when viewed from above.

MQ full-time rocker arm 10. +2 is a slipper portion 10a on the cams 3a, 3b of the camshaft 3 as shown in FIG.
,! 2a, and is driven to swing freely around the rocker shaft 8.9 following the cams 3a and 3b, thereby constantly opening and closing the intake valve 6 and the exhaust valve 7.

In FIG. 2, 14 is a valve kite, 15 is a valve spring, and +6 is a valve spring retainer.

The switching type rocker arm IIS+3 is operated by the control mechanism 21 according to the rotational condition of the engine (for example, the number of rotations), and for example, when the engine is in the high speed rotation range, it operates integrally with the full-time type rocker arm 10112 to correspond to the engine speed. On the other hand, when the ennon is in a low speed rotation range, it stops and does not drive the corresponding valve.

The controller tM 21 connects the switching type rocker arm 11.13 via a pin to the permanently acting type rocker arm 10.12.
a drive system 22 that interlocks with or disengages from the
It also includes a hydraulic operation system 23 that operates the drive system 22 according to the rotational speed of the engine.

To explain the control mechanism 21 using the intake side as an example, the full-time rocker arm 10 has a plunger pin 24 that can slide into the cylindrical hole of the switchable rocker arm 11 and is biased in the protruding direction by a spring 25. A return pin 27 that pushes back the plunger pins 2 and 1 under the force of a return spring 26 is housed in the switchable rocker arm II, and is located on the back side of the plunger pin 24 in the full-time rocker arm IO. The hydraulic chamber 28 formed in the rocker shaft 8 communicates with an oil passage 30 in the rocker shaft 8 via an oil passage 29 formed in the normally-acting rocker arm 10.

Here, the plunger bin 24, pin 27, and springs 25, 26 constitute a drive system 22 of the control mechanism.

On the other hand, to explain the control mechanism operation system 23, reference numeral 31 in FIG. 3 is an oil passage provided in the Schilling spatula Z cover 2. The tip side extends to the camshaft bearing portion 32, where it communicates with a circumferential groove 33 formed along the outer circumference of the camshaft 3. At locations facing the circumferential groove 33, four holes 34 extending in the radial direction are provided every 90 degrees in the circumferential direction.

A governor shaft (switching valve) 35 is disposed within the camshaft 3 so as to be rotatable relative to the camshaft 3.

Go f banner race 7 to 3CI+ end 1 piece is 1 piece: 1
゛, A governor 36 is installed in series. This centrifugal governor 36
The arm 36a is engaged with a notch 35a formed at the end of the governor shaft 35, as shown in FIG.
When the governor weight 3Gb attached to the arm 3Ga moves outward due to centrifugal force, the governor shaft 35
Rotate.

A circumferential groove 37 is formed on the outer periphery of the governor shaft 35 at a position facing the hole 34 of the camshaft 3 as shown in FIG. Four vertical grooves 38 extending in the circumferential direction are provided every 90 holes, and holes 39 extending in the radial direction are provided between the longitudinal grooves 38, and further, the governor shaft 3
A return oil passage 40 that communicates with the hole 39 is provided inside the camshaft 3. A hole in the return oil passage 40 is formed between the hollow hole 3C of the camshaft 3 and the cams 3a and 3b. It is guided to the outside of the camshaft 3 through the hole 3d, and lubricates a predetermined sliding movement rl in the engine (see FIG. 3).

The camshaft 3 has a hole (a discharge hole) extending in the radial direction at the same circumferential position as the hole 34 (located at η position) facing the three holes of the governor shaft 35.
The holes 4I are arranged on the same plane perpendicular to the axis of the camshaft 3. A circumferential groove 42 is formed in the camshaft bearing portion 32 of the cylinder head 1 so as to surround the hole 41.

As shown in FIGS. 1 and 2, the norinda head F'l is provided with an oil passage 44 extending linearly from the camshaft bearing 32 to the rocker bearing 43, and this I11 passage 4
4, the circumferential groove 12 communicates with an oil passage 30 in the rocker shaft 8.

The control gl1 is controlled by the oil passage 30, 31, 44, governor shaft 35, centrifugal governor 36, etc. described below.
A mechanism operation system 23 is also configured.

Note that the control mechanism on the exhaust side differs from that on the intake side in the arrangement of the plunger pin 24, return pin 27, and associated springs 25 and 26 between the full-time rocker arm and the switchable rocker arm. However, the basic configuration is the same as that of the intake side, and here the same components on the intake side as in Part B are given the same reference numerals and their explanations will be omitted.

Further, as shown in FIG. 2, one end of a temporary spring 51 is fixed by a bolt 52 to the inner surface of the cylinder head cover 2 at a location facing the switching type rocker arms 11 and I3. By this temporary spring 51, the rocker arm II
, 13 are biased so that their actuating parts abut against the valve stem end.

Further, a stopper 53 for preventing the leaf spring 51 from springing up is provided integrally with the cylinder head cover 2 on the inner surface of the cylinder head cover 2 facing the other end side of the temporary spring 51. Note that this stopper 53 does not need to be provided integrally with the cylinder cover 2, and may be integrally attached to the cylinder cover 2 using a separate fixing means such as a screw. Further, the material thereof is not limited to metal, but may be a non-metallic material such as hard nylon.

Next, the operation of the above-mentioned valve train will be explained.

When the engine is in a low rotational speed range, the switchable rocker arm I+, 13 is at rest.

That is, the centrifugal governor 36 rotates integrally with the camshaft 3.
is in a closed state because its rotation is low, and the governor weight 35 is shifted by one vertical position where the vertical groove 38 communicates with the holes 34 and 41, as shown in FIG. 6(b). The oil passage 3 in the rocker shaft 8.9 is closed by blocking the holes 34 and 41.
0 is the oil passage 14 and the circumference of the camshaft bearing portion 32 riIy4
2. Through the hole 41 and the hole 39 of the governor weight 35 which is connected to the hole 11, the governor
It communicates with the return oil passage IIO in 35.

Therefore, the original music from an oil pump (not shown) is not supplied to the hydraulic chamber 28 of the full-time rocker arm 10 on the intake side (switchable rocker arm 13 on the exhaust side), and
Due to the pressure being ravaged, no hydraulic pressure acts on the back of the planter pin 24. Therefore, the plunger bin 24 is pushed back by the return pin 27 and the permanent rocker arm l
0112 and the switchable type rocker arms 11 and 13 are engaged with each other, since the movement of the full-time rocker arm l0112, which swings and rotates following the cams 3a and 3b, is not transmitted to the switchable rocker arms II and 13. The intake valve 6 and the exhaust valve 7 are kept in an idle state, that is, in a valve inactive state.

Thereafter, when the engine rotational speed reaches a certain value, the governor weight 36b of the centrifugal governor 36 moves outward, and the arm 36a rotates the governor shaft 35 by a predetermined angle by the notch 35a of the governor shaft 35. The longitudinal groove 38 of the shaft 35 communicates with the holes 34, 41 formed in the camshaft 3, as shown in FIG. 6(A). Therefore, the original oil supplied from the main pump to the oil passage 31 has a circumferential groove 33, a hole 34, a circumferential groove 37, and a vertical groove 3, as shown in FIG.
8. Hole 41. It is supplied via the circumferential drain 742 to the oil channel 44 and from there to the hydraulic chamber 28 via the oil channels 30 and 29 in the rocker shaft 8.9.

Note that the leak hole 39 is shifted to a position that does not allow the hole 41 of the shaft 3 and the return oil passage 40 to communicate with each other.

As a result, on the intake side, the planter pin 24 protrudes into the switchable rocker arm 11 (and vice versa on the exhaust side), so that the full-time rocker arm and the switchable rocker arm engage with each other. For this reason, the cams 3a, 3b
As a result, the switching type rocker arms II, +3 are oscillated together with the permanent type rocker arm 10.12, which oscillates, and all the intake valves 6 and exhaust valves 7 are driven.

Although the embodiment is a single-cylinder four-valve engine, it can also be applied as a mechanism for stopping cylinders in a multi-cylinder engine.

``Effects of the Invention'' As explained above, according to the present invention, the control mechanism drive system is switched and the switching valve is operated by a centrifugal governor, making it difficult to switch between valve operation and rest, which was previously considered difficult. This can be done by mechanical means, which makes it possible to reduce the number of parts and reduce costs.

In addition, a switching valve is built into the camshaft, and the switching valve pressure oil discharge hole of the force 11 shaft and the oil passage in the rocker shaft are communicated through an oil passage that linearly connects their bearings. It is possible to obtain the operating system oil passage of the control mechanism in the shortest distance, and realize switching with excellent responsiveness.

In addition, the operating system oil passage for the surface control mechanism is secured by combining the shaft and its bearing, which are engine components, without using special parts such as tubes, so in this sense, costs can be reduced. , and the effects such as easier parts management can be obtained.

[Brief explanation of drawings]

Figures 1 to 6 (A) and (B) show one embodiment of the present invention; Figure 1 is a plan view of the front panel with the front cover removed, and Figure 2 is a diagram showing ■-■ in Figure 1. Sectional view along line, 3rd
The figure is a sectional view taken along line [II-[ in FIG. 1. Figure 4 is a side view of the centrifugal governor, Figure 5 is a perspective view of the governor shaft, and Figures 6 (a) and 6 (b) are cross-sectional views taken along the line Vl-Vl in Figure 3. FIG. l... cylinder head, 3... camshaft, 6... intake valve, 7... exhaust valve, 8... intake side Rocker shaft, 9...Exhaust side rocker shaft, 10, +2...Full-time rocker arm, 11.13
...Switchable rocker arm, 2I...Control mechanism, 22...Control mechanism drive system, 23...Control mechanism operation system 1. 31), 31, 4 0 ・-,,,-,l
Nora g8.35... Governor shaft (switching valve), 36. Centrifugal force, 33.37.42... Circumferential groove, 41... Hole (oil flavor outlet).

Claims (1)

[Claims] This is a so-called SOHC type internal combustion engine in which only one camshaft for one cylinder is placed at the top of the cylinder head, and a rocker shaft is provided on both sides of the top of the camshaft, and a rocker arm is attached to the rocker shaft. A hydraulically operated control mechanism is provided which is swingably supported and which brings some or all of the rocker arms to a rest state depending on the operating status of the engine. an oil supply source; a switching valve operated by a centrifugal governor, the switching valve communicating with the pressure oil supply source and being incorporated inside the camshaft;
It is constituted by an oil passage communicating with the switching valve and formed in the rocker shaft, and an oil passage connecting the oil passage and the operating system of the control mechanism, and the plurality of discharge holes of the switching valve are connected to the camshaft. A bearing part that supports the camshaft of the cylinder head is provided on the same plane perpendicular to the axis of the cylinder head, and a circumferential groove is provided so as to surround the discharge hole of the switching valve. A valve train with a stop function for an internal combustion engine, characterized in that the oil passage is communicated by an oil passage extending linearly from a camshaft bearing part of a cylinder head to a rocker shaft bearing part.