JPS62218653A - Phase adjusting device between different kind of camshafts in internal combustion engine - Google Patents

Abstract

PURPOSE:To enable the simplification in the structure of a fuel injection device by carrying out the spark-advance or -retard control in the fuel injection timing by changing relatively the phases of intake-exhaust cams and a fuel cam. CONSTITUTION:A phase adjusting device Z carries out the spark-advance or -retard control in a fuel injection device by the operating oil being supplied alternatively into the first all chamber 22 or the second oil chamber 23 in response to the operating conditions of an engine. In other words, when the engine reaches a prescribed high speed condition, high-pressure operating oil is introduced into the first oil chamber 22 side by the changeover action of an electromagnetic changeover valve 40, and at the same time the second oil chamber 23 is connected to a tank side 48, and a piston 30 is shifted in the direction of an arrow A by the oil pressure applied on the first pressure receiving surface 33. In this case, the fuel cam 20 on a fuel camshaft 15 is relatively turned by a prescribed angle in the spark-advance direction against both intake and exhaust cams 6, 7 on an intake-exhaust camshaft 1 in accordance with the twisted angle of the second sprine 18 and the fourth sprine 36.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a phase adjustment device between different types of camshafts in an internal combustion engine, and more specifically, to a phase adjustment device for adjusting the phase between different types of camshafts in an internal combustion engine, and more particularly, to This relates to a phase adjustment device between the two.

(Prior art) A composite camshaft in which a cam for driving an intake valve (intake cam), a cam for driving an exhaust valve (exhaust cam), and a cam for driving a fuel injection device (fuel cam) are installed on a single shaft body has already been developed. This conventional composite camshaft has the advantage that the various cams mentioned above are integrally formed on a single shaft, which simplifies the configuration of the camshaft. However, a new problem arises in that it is not possible to mutually adjust the phase between the cams.

In other words, in an internal combustion engine, it is necessary to advance or retard the fuel injection timing (advance or retard) according to changes in rotation speed, but with the above compound camshaft, it is not possible to individually change the phase of only the fuel cam. I couldn't do it.

(Problems to be Solved by the Invention) The present invention provides a composite camshaft equipped with several different types of cams (intake cam, exhaust cam, fuel cam) as described above.
Among these cams, the fuel cam that requires phase adjustment is intended to be detachably separated from other cams so that phase adjustment can be performed independently.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides an intake/exhaust cam shaft that is provided with an intake cam and an exhaust cam and is hollow inside. Further, a fuel cam for driving a fuel injection device is loosely fitted around the outer periphery of the intake/exhaust camshaft at a position overlapping with the window hole so as to be relatively rotatable, while a hollow of the intake/exhaust camshaft is formed. A fuel camshaft for driving the fuel cam is fitted into the part so as to be rotatable relative to the intake/exhaust camshaft, and the fuel camshaft and the fuel cam are inserted into the window hole in the direction of rotation of the fuel camshaft. A cylindrical piston with a helical spline is interposed between the intake/exhaust camshaft and the fuel camshaft so as to be movable in the axial direction. The present invention is characterized in that a hydraulic circuit is provided for selectively applying hydraulic pressure to two opposing pressure receiving surfaces.

(Function) The present invention uses the above means to relatively change the phases of the intake/exhaust cam and the fuel cam, which are located on the same axis, by the hydraulic control means in a composite camshaft equipped with the intake/exhaust cam and the fuel cam. Since the advance/retard operation of the fuel injection timing is performed using the fuel injection device, there is no need to provide a dedicated advance/retard operation device for the fuel injection device, and the structure of the fuel injection device can be simplified.

(Embodiment) Hereinafter, a preferred embodiment of a phase adjustment device between different types of camshafts in an internal combustion engine of the present invention will be described based on FIGS. 1 and 2.

FIG. 1 shows a phase adjusting device Z between different types of camshafts according to an embodiment of the present invention. The symbol X is a composite camshaft which is the main part of the present invention, and this composite camshaft Equipped with intake/exhaust camshaft l and fuel injection device (
fuel cam 20 for driving the unit injector)
．． The fuel camshaft 15 has a fuel camshaft 15 equipped with a fuel camshaft 20.

The intake/exhaust camshaft 1 is formed into a hollow shape with one end open and the other end closed, and a fuel camshaft 15, which will be described in detail later, is fitted into the hollow part 3 so as to be relatively rotatable. be done. The intake/exhaust camshaft 1 has a sparse spline (hereinafter referred to as a first spline) 8 formed at one end of the inner peripheral surface 1a on the opening side.

Also, the intake/exhaust camshaft l is the outer peripheral surface! Intake cam on b 6.6. . . , exhaust cams 7.7, . has been done. The window hole 9 is formed to reach the outer circumferential surface 1b from inside the hollow portion 3 of the intake/exhaust camshaft 1, and a fuel camshaft 15 and each fuel cam 2, which will be described in detail later, are inserted into the window hole 9.
The key member 25 that connects the 0 and 0 is loosely fitted.

The fuel camshaft 15 has an oil passage I7 formed therein and a helical spline (hereinafter referred to as a second spline) having an appropriate twist angle at one end of its outer peripheral surface 15a.
1g is formed. As shown in FIG. 2, the key member 25 attached to the fuel camshaft 15 is inserted into the window hole 9 of the intake/exhaust camshaft 1 by an appropriate length outside the window hole 9. A fuel cam 2 for driving a fuel injection device is provided on a protruding portion of the key member 25.
0 engagement groove 24 is engaged. The fuel cam 20 has a two-part shape (numeral 20A).

20B) and is mounted so as to cover the window hole 9 of the intake/exhaust camshaft I and to be rotatable on the outer peripheral surface Ib of the intake/exhaust camshaft I, and is integrated with bolts 21 and 21. . That is, when the fuel cam shaft 15 rotates relative to the intake/exhaust cam shaft I, the fuel cam 2o is rotated in the same direction via the key member 25.

When the fuel camshaft 15 is fitted into the hollow portion 3 of the intake/exhaust camshaft l, one end side of the composite camshaft
An annular gap 28 for fitting a phase adjustment piston 30, which will be described in detail later, is formed between the inner circumferential surfaces 1a of the piston. The first oil chamber 22 located on one side of 30
and a second oil chamber 23 located on the other side. Further, among the eleventh second oil chambers 22 and 23, the first oil chamber 22 is connected to the oil passage 51 formed in the casing 50 via the oil passage 11 formed in the intake/exhaust camshaft I. The two oil chambers 23 are communicated with an oil passage 52 formed in the casing 50 via the oil passage 17 of the fuel camshaft 15 and the oil passage 12 of the intake/exhaust camshaft I, respectively. The oil passages 51 and 5 of the casing 50
2 is alternatively connected to a hydraulic pump 43 via an electromagnetic switching valve 40.
will be communicated with.

The piston 30 is formed into a cylindrical shape, and its outer peripheral surface 3
A sparse spline (hereinafter referred to as the third spline) that meshes with the first spline 8 of the intake/exhaust camshaft l at 0a.
A helical spline (hereinafter referred to as a fourth spline) 36 that meshes with the second spline 18 of the fuel camshaft 15 is formed on the inner peripheral surface 30b of the fuel camshaft 35 and the inner circumferential surface 30b thereof. The piston 30 is fitted into an annular gap 28 formed between the intake/exhaust cam shaft I and the fuel cam M15. Furthermore, among both end surfaces 33 and 34 of the piston 30,
The surface located in the first oil chamber 22 is the first pressure receiving surface 33, the second pressure receiving surface
The surface located in the oil chamber 23 becomes the second pressure receiving surface 34. In this fitted state of the piston 30, the third spline 35 of the piston 30 and the first spline 8 of the intake/exhaust camshaft 1 are connected, and the fourth spline 36 of the piston 30 and the second spline of the fuel camshaft 15 are connected to each other. The splines I8 are engaged with each other so as to be relatively slidable in the axial direction (arrow AB direction). Therefore, by appropriately switching the electromagnetic switching valve 40 according to the operating state of the engine (engine speed), the hydraulic oil for driving the piston can be selectively supplied to the first oil chamber 22 or the second oil chamber 23 side. When the piston 30 is introduced, the piston 30 is moved in the direction of arrow A-B, and the fuel camshaft 1
5 is rotated relative to the intake/exhaust camshaft l, thereby realizing a mutual phase change between the two shafts.

In this embodiment, when the piston 30 moves in the direction of the arrow, the fuel camshaft 15 rotates relative to the intake/exhaust camshaft l in the advance angle direction, and the piston 30 moves in the direction of the arrow B. The torsional direction of the fourth spline 36 and the second spline 18 of the fuel camshaft 15 is set so that the fuel camshaft 15 rotates relative to the intake/exhaust camshaft I in the retard direction when this occurs.

In addition, in FIG. 1, numerals 13 and 14 are bearing parts, 37 is a stopper of the piston 30, 38 is a shaft plate is a stopper member, 3
9 is a blind lid, 53 is a drain, and in FIG. 2, reference numeral 26 is a bolt insertion hole.

Next, the operation of the phase adjustment device Z between different types of camshafts in the illustrated embodiment will be explained. are connected to each other via a piston 30, and when receiving driving force from the engine through a gear 55 attached to one end of the intake/exhaust camshaft l, both shafts 1 and 15 rotate integrally in synchronization. The intake cams 6.6... control the opening and closing of the intake valves, the exhaust cams 7.7... control the opening and closing of the exhaust valves, and the fuel cams 20.20... drive the fuel injection device (unit injector) to inject the engine into the engine. Supply fuel.

On the other hand, this device Z controls the advance angle and timing of the fuel injection device by means of a working pressure which is selectively supplied into the first oil chamber 22 and the second oil chamber 23 depending on the operating state of the engine (engine speed). Perform retard operation. That is, when the engine reaches a predetermined high rotational state, the switching operation of the electromagnetic switching valve 40 causes the first
High-pressure hydraulic oil is introduced into the oil chamber 22 side, while the second oil chamber 23 is connected to the tank 48 side, and the piston 30 is displaced in the direction of the arrow by the hydraulic pressure acting on its first pressure receiving surface 33. . At this time, the fuel cam 20 of the fuel camshaft 15 is set in a predetermined advance direction relative to the intake/exhaust cam 6.7 of the intake/exhaust camshaft l according to the torsion angle of the second spline I8 and the fourth spline 36. The relative rotation is made by the angle (
advance angle operation).

On the other hand, when the engine is in a low rotational state and it becomes necessary to retard the fuel injection timing (retard operation), the electromagnetic switching valve 40 is operated to change the timing, contrary to the advance operation. 2
While high-pressure hydraulic oil is introduced into the oil chamber 23, the first oil chamber 22 is connected to the tank 48 side, and the piston 30 is displaced in the direction of arrow B by the hydraulic pressure acting on its second pressure receiving surface 34. . At this time, the second spline! 8 and the fourth spline 36, the fuel cam 20 of the fuel camshaft 15 is rotated by a predetermined angle in the retard direction relative to the intake/exhaust cam 6.7 of the intake/exhaust camshaft l. (
retard operation).

In both the advance and retard operations described above, since the key 25 is loosely fitted into the window hole 9, the intake/exhaust camshaft 1 and the fuel camshaft 15 can be rotated relative to each other.

(Effects of the Invention) As is already clear from the above description, the present invention provides a composite camshaft in which an intake/exhaust camshaft and a fuel camshaft are coaxially connected, and in which the Since both shafts can be rotated relative to each other, it is possible to change the phase of only the fuel cam (advance or retard operation) even with a composite camshaft such as the one described above, which improves the camshaft structure. This has the effect of simplifying the structure of the fuel injection device (omitting the timer device) as well as simplifying the structure of the fuel injection device.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part of a phase adjustment device between different camshafts in an internal combustion engine according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view of the main part of FIG. 1...Intake/exhaust cam shaft la...Inner peripheral surface of intake/exhaust cam shaft 3...Hollow part 6...Intake cam 7...Exhaust cam 8 ...First spline 9 ... Window hole L5 ... Fuel camshaft 15a ... Outer peripheral surface of fuel camshaft ■8 ... Second spline 20 ... Fuel Cam 25...Key member 30...Piston 33.34...Pressure surface 35...Third spline 36...Fourth spline

Claims (1)

[Claims] 1. A window hole (9) extending from the hollow part (3) to the outer circumferential surface (1b) is provided in the intake/exhaust cam shaft (1), which is equipped with an intake cam (6) and an exhaust cam (7) and is hollow inside. The intake/exhaust camshaft (
A fuel cam (20) for driving a fuel injection device is loosely fitted on the outer periphery of the fuel injection device so as to be relatively rotatable, while the intake/exhaust cam shaft (1)
) A fuel camshaft (15) for driving the fuel cam (20) is fitted into the hollow part (3) so as to be rotatable relative to the intake/exhaust camshaft (1). (15) and the fuel cam (20) are coupled by a key member (25) loosely fitted into the window hole (9) so as to be freely displaceable in the direction of rotation of the fuel cam shaft, and the intake/exhaust cam shaft ( A cylindrical piston (30) with a helical spline (36) is disposed between the fuel camshaft (15) and the fuel camshaft (15) so as to be freely displaceable in the axial direction, and the piston (30) receives two opposing pressures in the axial direction. surface(
33) A phase adjusting device between different types of camshafts in an internal combustion engine, characterized in that a hydraulic circuit for selectively applying hydraulic pressure is provided in (33) and (34).