JPS603286Y2 - Internal combustion engine valve train - Google Patents

Description

[Detailed description of the invention] The present invention relates to a valve train for an internal combustion engine, and more specifically, the invention is concerned with a valve train for an internal combustion engine, and more specifically, the timing of opening and closing of intake valves, exhaust valves, etc. is delayed depending on the rotational speed of the internal combustion engine. This is a valve train for internal combustion engines that improves performance such as engine output, fuel efficiency, and efficiency both when rotating and at low speeds, and is installed in engines that are in practical use without major design changes. Regarding possible devices.

The performance of an internal combustion engine, such as output, fuel efficiency, and efficiency, is largely dependent on the characteristics of the cam that opens and closes the engine's on-off valve.

In an engine where one type of cam always rotates in the same phase with respect to the engine crankshaft, if the cam is set for high speed operation, the engine operating characteristics during low speed operation will be sacrificed, and conversely, if the cam is set for low speed operation, the engine operating characteristics will be sacrificed. Engine operating characteristics during high-speed operation are sacrificed.

As a countermeasure for this, for example, U.S. Patent No. 3.262゜435
As described in the specification, a camshaft drive member mechanically connected to the crankshaft of an internal combustion engine is connected to a camshaft for operating an engine opening/closing valve via an elastic member whose deflection increases depending on the load. However, there is a known valve train that delays the opening/closing timing of the engine on-off valve in response to an increase in engine speed; however, according to the results of experiments, this device actually Accordingly, the required driving force of the camshaft does not increase, but decreases slightly, or remains almost constant, and therefore the opening/closing timing of the engine opening/closing valve cannot be delayed as expected in accordance with the increase in engine speed. There was a problem that desired engine operating characteristics could not be obtained.

In order to improve this, the present applicant previously applied for
No. 124735 discloses a camshaft to which a cam that opens and closes an on-off valve of an internal combustion engine is attached via an elastic member that increases the amount of deflection of a camshaft drive member mechanically connected to the crankshaft of an internal combustion engine, depending on the load. In a valve train for an internal combustion engine connected to an internal combustion engine, an engine auxiliary machine whose required driving force increases as the engine speed increases is connected to the camshaft so that the relative delay force of the camshaft increases as the engine speed increases. We proposed a valve train for internal combustion engines that improves engine performance.

The inventor of the present invention arrived at the present invention as a result of further studies in order to be able to easily install the valve train of this invention into a practical engine.

In other words, a camshaft drive member mechanically connected to the crankshaft of the internal combustion engine is connected to a camshaft for operating engine opening/closing valves via an elastic member whose deflection increases depending on the load, and the camshaft drive member is mechanically connected to the crankshaft of the internal combustion engine. In a valve operating system for an internal combustion engine that automatically delays the opening/closing timing of an engine on/off valve, an input shaft is connected to an engine auxiliary equipment whose required driving force increases as the rotational speed increases, and the input shaft is connected to the engine auxiliary equipment via the elastic member. A valve operating device for an internal combustion engine, characterized in that a camshaft driving member is directly connected to a driven member, and the driven member is connected to the camshaft via a band-shaped power transmission element.

By adopting such a configuration of the present invention, the required force for driving the camshaft increases as the engine speed increases, and the opening/closing timing of the engine opening/closing valve is reliably delayed, and the desired engine characteristics can be obtained. It has also become easier to install it in engines.

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

A crank pulley 5 is fixed to a crankshaft 3 of an engine 1, and a timing belt 9 is stretched between the crank pulley 5 and a drive pulley 7, which is a camshaft drive member of the present invention, to mechanically connect the crank pulley 5 to the crankshaft 3 of the engine 1.

The timing belt 9 is preferably a puffer belt to prevent slippage between the pulley and the belt.

An input shaft 11a of an auxiliary machine 11 is positioned coaxially with the drive pulley 7, and a driven pulley 13, which is a driven member of the present invention, is fixed to the input shaft 11a.

An elastic member 15 is provided between the driving pulley 7 and the driven pulley 13 so that the amount of deflection of the elastic member 15 increases depending on the load.

With reference to FIGS. 2 and 3, the input shaft 11a of the auxiliary equipment 11
A cylindrical transmission member 16 is fixed in parallel with the driven pulley 13, and the drive pulley 7 is provided coaxially with the transmission member 16 so as to be rotatable therewith, and an elastic force is provided between the drive pulley 7 and the transmission member 16. A spring serving as a member 15 is stretched.

In addition to the above-mentioned structure, the elastic coupling mechanism is disclosed in U.S. Patent No. 3.
It may be similar to that described in No. 262.435.

Referring again to FIG. 1, a cam pulley 19 is fixed to the camshaft 17 in alignment with the driven pulley 13, and a band-shaped power transmission element such as a timing belt 21 preferably made of a cog belt is installed between the driven pulley 13 and the cam pulley 19. Stretch the
The rotation of the driven pulley 13 is transmitted to the camshaft 17 via the cam pulley 19.

The camshaft 17 extends in the longitudinal direction of the upper part of the engine 1, is rotatably supported by a bearing 23, and opens and closes the intake valve and exhaust valve (both not shown) of each cylinder of the engine on the camshaft 17. The operating intake valve opening/closing cam 25 and exhaust valve opening/closing cam 27 are fixed.

As shown in Fig. 4, the aforementioned auxiliary equipment 11 is used for pumps conventionally installed near the engine, such as air pumps, oil pumps, power steering pumps, and air conditioner pumps, whose required driving force increases as the rotation speed increases. Represented.

A generator can also be used as an engine auxiliary machine.

The engine auxiliary equipment 11 may be of any type as long as the required driving force increases as the rotational speed increases, but in particular, impeller-type pumps have a constant torque during one rotation, and vibrations occur on the camshafts 17, 25, and 27. It is preferable because it does not cause

Alternatively, the engine auxiliary equipment 11 may be provided with a relief valve for preventing excessive pressure, so that the characteristics as shown by the chain line in FIG. 4 may be obtained.

The present invention having the above configuration can be installed in a conventional engine with only a slight design change, and with this configuration, the camshaft driving force required for the present invention device increases as the engine speed increases, as shown by the solid line A in Fig. 5. increases as shown in .

As a result, as the rotational speed of the engine increases, the amount of deflection of the elastic member increases, and the driven pulley lags behind the driving pulley, causing the phase to lag from the solid line I to the dashed-dotted line ■, and further as shown by the dashed-dotted line ■ in FIG.

Therefore, performance such as output, fuel efficiency, and efficiency of the engine can be improved both when the engine rotates at high speed and when it rotates at low speed.

In FIG. 5, the dashed line B and the broken line C are the required force diagrams for driving the camshaft in a conventional valve train, and are shown in U.S. Patent No. 3.
The conventional device described in No. 262.435 was unable to retard the cam phase as the engine speed increased as in the present invention.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of the device of the present invention, Fig. 2 is a front view of the elastic coupling mechanism shown in Fig. 1, Fig. 3 is a side view of Fig. 2, and Fig. 4 is the required drive of the auxiliary equipment shown in Fig. 1. FIG. 5 is a diagram of the force required to drive the camshaft in FIG. 1, and FIG. 6 is a diagram of the cam lift amount. 1... Engine, 3--- Crankshaft, 5.
... Crank pulley, 7 ... Drive pulley (camshaft drive member), 9 ... Timing belt, 11 ... Auxiliary machine, 11a ...・Input shaft,
13... Driven pulley (driven member), 15...
... Spring (elastic member), 17 ... Camshaft, 2
1... Timing belt (band-shaped power transmission element)
.

Claims (1)

[Scope of Claim for Utility Model Registration] ■ A camshaft drive member mechanically connected to the crankshaft of an internal combustion engine is connected to a camshaft for operating an engine opening/closing valve via an elastic member that increases the amount of deflection according to the load. In a valve operating system for an internal combustion engine that automatically delays the opening/closing timing of an engine on-off valve according to an increase in engine speed, the input shaft of an engine auxiliary machine whose required driving force increases as the engine speed increases. A valve operating device for an internal combustion engine, characterized in that the camshaft drive member is directly connected to a driven member via the elastic member, and the driven member is connected to the camshaft via a band-shaped power transmission element. 2. The valve operating system for an internal combustion engine according to claim 1, wherein the engine auxiliary equipment is an impeller-type pump.