JPH09125923A - Intake/exhaust valve drive control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply to pins a lubricating oil introduced into an annular disk from a drive shaft. SOLUTION: A cylindrical camshaft 22 is placed on the outer periphery of a drive shaft 21 which rotates in synchronization with an engine, and an annular disk 29 is placed between the first flange part 27 of the camshaft 22 and the second flange part 32 of the camshaft which is secured to the drive shaft 21. The annular disk 29 is held by a movable control ring 35 and is connected to the ring 35 by a pair of pins 36, 37. When the annular disk 29 comes to an eccentric position, the camshaft 22 is rotated at nonuniform speed, and a valve lift characteristic is varied. The surfaces 27a, 32a of the flanges make contact with the side faces 29c, 29d of the annular disk 29 so that lubricating oil introduced to the inner periphery of the annular disk 29 from a lubricating oil passage 23 in the drive shaft 21 efficiently flows to the pins 36, 37 through engaging grooves 30, 33.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake / exhaust valve drive control device for variably controlling the opening / closing timing and operating angle of an intake / exhaust valve according to the operating state of an internal combustion engine.

[0002]

2. Description of the Related Art Various types of devices for variably controlling the opening / closing timings and operating angles of intake and exhaust valves have been conventionally provided.
There is one described in Japanese Patent Publication No. 306.

FIGS. 10 and 11 show this conventional intake / exhaust valve drive control device. The outline thereof will be described. In FIG. 10, reference numeral 2 is rotatably provided on the outer periphery of a drive shaft 1, and an intake valve is provided. A cam for opening 16 of the valve spring 17 against the spring force of the valve spring 17, and the cylindrical cam 2 includes a cam bearing bracket 3 and a flange portion 5 fixed to the drive shaft 1 via a key 4. Positioning in the axial direction is performed by and.
Further, the flange portion 7 having the engagement groove 6 on one side portion of the cam 2
On the other hand, the engaging groove 8 is formed in the flange portion 5 as well.
Is formed, and an annular disk 9 is interposed between the flange portions 5 and 7. The disk 9 has pins 10 and 11 which engage with the engaging grooves 6 and 8 at opposite positions on both sides.
Is provided, and the outer periphery is rotatably held by the control ring 12. This control ring 12 has a protrusion 1 on the outer circumference.
A gear portion 12b, which is swingably supported by a support hole 13 on the cylinder head side via 2a, is located on the opposite side of the projection 12a meshes with a gear ring 14a on the outer circumference of the rocker shaft 14.

The control ring 12 includes a gear ring 14a.
The drive mechanism (not shown) swings in one or the other direction depending on the operating state of the engine via the gear unit 12b and the gear unit 12b. That is, when the center C of the disk 9 is at the position shown in FIG. 10, the rotation centers of the drive shaft 1 and the disk 9 coincide with each other, and therefore the disk 9 has the pin 11 and the engaging groove 8
The motor 2 is synchronously rotated at a constant speed with the drive shaft 1, and the cam 2 is synchronously rotated at a constant speed with the disk 9 through the pin 10 and the engaging groove 6.

A rocker shaft 1 that supports a rocker arm 15 by a driving mechanism in accordance with a change in the engine operating state.
When the control ring 4 is rotated, the control ring 12 swings around the protrusion 12a, whereby the center C of the disk 9 is
Eccentric to the center of In this state, the disk 9 having the engaging grooves 6 and 8 and the pins 10 and 11 constitute a kind of eccentric shaft coupling, and the cam 2 rotates following the drive shaft 1, but the rotational speeds of both are not constant. It becomes constant speed. That is,
During one rotation of the drive shaft 1, the rotation phase of the disk 9 changes with respect to the drive shaft 1, and at the same time, the rotation phase of the cam 2 also changes with respect to the disk 9. Therefore, the cam 2 causes a phase difference with respect to the drive shaft 1 as shown by a broken line or a dashed line in FIG. 12A, and as a result, as shown in FIG. 12B, a valve lift characteristic shown by a solid line. Can be changed like a broken line or an alternate long and short dash line. The point P is
This is the point where the rotational phase difference is always kept at zero.

[0006]

In the intake / exhaust valve drive control device of the above-mentioned type, the contact portions between the pins 10 and 11 and the engaging grooves 6 and 8 and the pins 10 and 1 in the disk 9 are formed.
Lubrication of the fitting surface of No. 1 is an important issue. This pin 10,
Although the lubrication of No. 11 is not described in detail in the above publication, generally, the drive shaft 1 is made hollow to form a lubricating oil passage therein, and the lubricating oil is supplied to the inner peripheral surface of the disk 9 from here. Then, the centrifugal force causes the lubricating oil toward the outer peripheral side to flow along the engagement grooves 6 and 8 to flow near the pins 10 and 11.

However, in the above conventional apparatus, as shown in FIG. 11, the disk 9 and the flange 5,
Since there is a gap between the inner peripheral surface of the disk 9 and the engaging grooves 6 and 8 which are not surrounded by the flow path of the lubricating oil, even if the lubricating oil is supplied to the inner peripheral surface of the disk 9, most of the above-mentioned gap is present. Is scattered to the outer peripheral side, and only part of the lubricating oil is supplied to the pins 10 and 11. That is, there was a problem that the pins 10 and 11 were not reliably lubricated.

[0008]

SUMMARY OF THE INVENTION Therefore, according to the present invention, a drive shaft that rotates in synchronism with the rotation of an engine and a cam that is rotatably fitted to the outer periphery of the drive shaft and that drives an intake / exhaust valve. A cylindrical cam shaft having an outer periphery, a first flange portion provided in a flange shape at an end portion of the cam shaft, and having a first engaging groove formed in the radial direction, and the first flange portion. A second flange portion, which is provided on the drive shaft side so as to face each other and has a second engaging groove formed in the radial direction, and an annular disc disposed between the flange portions. A pair of pins projecting from opposite sides of the annular disc in opposite directions and engaged in the engagement grooves of the flanges respectively, and the annular disc rotatably held and along the direction perpendicular to the axis. The control ring that can be moved by In an intake / exhaust valve drive control device for an internal combustion engine, which includes a drive mechanism that moves according to the state, lubricating oil is introduced into the inner periphery of the annular disk through a lubricating oil passage inside the drive shaft, and each flange portion The contact surface between the flange surface and the side surface of the annular disk is formed along both side edges of each engagement groove, and the outer peripheral end of this contact surface is defined by the inside of the pin and the engagement groove when the annular disk is maximally eccentric. It is characterized in that it is extended from the contact point on the peripheral side to the position on the outer peripheral side.

The lubricating oil introduced into the inner circumference of the annular disk through the lubricating oil passage inside the drive shaft tends to move toward the outer peripheral side by the centrifugal force, and therefore flows into each engaging groove and the engaging groove Propagate to the outer circumference. Here, since each engaging groove is surrounded on both sides by the contact surface between the flange surface and the side surface of the annular disk, it is guided to the outer peripheral side without leaking through the gap between them. Since the contact surface extends from the inner peripheral contact point between the pin and the engaging groove to the outer peripheral side, most of the lubricating oil flowing into the engaging groove is reliably supplied to the pin.

According to the invention of claim 2, the pin is rotatably fitted in the holding hole of the annular disk. In this case, it is necessary to lubricate the fitting surface between the pin and the holding hole, but since a large amount of lubricating oil is supplied to the pin through the engaging groove, the lubricating oil also lubricates the fitting surface at the same time.

Further, in the invention of claim 3, the pin is
A cylindrical base portion rotatably fitted in the holding hole, and a tip portion forming a parallel flat surface portion that engages with the engaging groove, and along the fitting surface of the holding hole and the pin. , An oil groove extending in the axial direction is formed. Therefore, as described above, part of the lubricating oil supplied to the pin smoothly flows between the holding hole and the pin through the oil groove, and the fitting surface thereof is reliably lubricated.

Further, in the invention of claim 4, the flange surface is formed in the same plane up to the outer peripheral end of each engaging groove, and the axial thickness of the portion of the control ring overlapping the outer peripheral portion of the flange portion. Is thinner than the annular disc. By thinning a part or the whole of the control ring in this way, interference between each flange portion and the control ring at the time of eccentricity can be avoided.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of an intake / exhaust valve drive control device according to the present invention will be described below with reference to FIGS. FIG. 1 shows only a main part of an intake / exhaust valve drive control device according to the present invention. In FIG. 1, reference numeral 21 denotes a drive shaft to which torque is transmitted from an engine crankshaft (not shown) via a sprocket. , 22 are hollow cylindrical camshafts arranged on the outer periphery of the drive shaft 21 so as to be relatively rotatable and provided coaxially with the center of the drive shaft 21. Drive shaft 2
The reference numeral 1 extends in the front-rear direction of the engine and is formed in a hollow shape having a lubricating oil passage 23 in the center. Further, the camshaft 22 is configured to be divided for each cylinder. In the drawing, only the end of the camshaft 22 is shown.

The cam shaft 22 is rotatably supported by a cam bearing (not shown) at the upper end of the cylinder head, and has a cam for opening and closing the intake / exhaust valve at a predetermined position on the outer circumference. Further, the camshaft 22 is divided into a plurality of pieces as described above, and a first flange portion 27 spreading like a flange is provided at one end of each. The divided camshaft 2
2 between the ends of the sleeve 28 and the annular disc 2 respectively.
9 are arranged.

As shown in FIGS. 3 and 5, the first flange portion 27 is provided with an elongated rectangular first engaging groove 30 extending in the radial direction from the hollow portion, and an annular disc 29. Flange surface 27 slidingly contacting one side surface 29c
a. The first engagement groove 30 has a slit-like opening at the flange-shaped portion of the first flange portion 27.

The sleeve 28 is arranged adjacent to the other end of the cam shaft 22 of the adjacent cylinder, and is fitted and fixed to the outer periphery of the drive shaft 21. In addition, a second flange portion 32 facing the first flange portion 27 on the camshaft 22 side is formed at a distal end portion of the sleeve 28. As shown in FIGS. 3 and 5, the second flange portion 32 has an elongated rectangular second engaging groove 33 extending in the radial direction.
And has a flange surface 32a that is in sliding contact with the other side surface 29d of the annular disk 29. The second engagement groove 33 is provided on the camshaft 22 side flange portion 2
7 are arranged on the opposite side from the first engagement groove 30 by 180 °.

The annular disc 29 has a substantially toroidal plate shape and has an inner diameter set so as to maintain a sufficiently large annular gap with the outer peripheral surface of the drive shaft 21.
9a is rotatably held on the inner peripheral surface of the control ring 35 having an annular shape. Further, holding holes 24 and 25 are formed at opposite positions on diameter lines different from each other by 180 °, and the holding holes 24 and 25 have first pins 36, which engage with the engagement grooves 30 and 33, respectively. The second pins 37 are fitted and arranged. The pins 36 and 37 project in opposite directions to each other in the axial direction of the camshaft, and cylindrical bases are rotatably fitted and supported in the holding holes 24 and 25, and project from the surface of the annular disc 29. At the tip end portion, parallel flat surface portions 36a and 37a having a two-face width are formed in surface contact with the inner surfaces of the engaging grooves 30 and 33 facing each other. The axial positioning of the pins 36 and 37 is determined by the steps 36b and 37b and the flange surfaces 27a and 32a formed between the cylindrical surfaces of the pins 36 and 37 and the flat surfaces 36a and 37a in the projecting direction. The pin 3 which penetrates the holding holes 24, 25 by contact with
This is performed by abutting the base end faces of 6, 37 and the flange faces 32a, 27a.

In order to guide the lubricating oil from the lubricating oil passage 23 of the drive shaft 21 to the inner peripheral surface 29b of the annular disc 29, one portion along the radial direction is formed in the portion of the drive shaft 21 which penetrates the annular disc 29. A plurality of oil holes 38 are formed.

The control ring 35 is constructed so as to be movable in the direction of arrow Z along a plane orthogonal to the axial direction of the drive shaft 21, and is driven by a drive mechanism (not shown) such as hydraulic pressure depending on engine operating conditions. And is moved in the direction of arrow Z. In other words, with the movement of the control ring 35, the rotation center Y of the annular disk 29 is eccentric from the rotation center X of the drive shaft 21 and the camshaft 22.

That is, under a predetermined operating condition of the engine, for example, in a high speed range, as shown in FIGS. 2 and 3, the center Y of the annular disk 29 and the center of the drive shaft 21 are passed through a hydraulic mechanism (not shown). The position of the control ring 35 is controlled so that X matches. In this case, a rotational phase difference does not occur between the annular disc 29 and the drive shaft 21, and since the center of the camshaft 22 and the center of the annular disc 29 also coincide with each other, no rotational phase difference occurs between them. . Therefore, the drive shaft 21, the annular disc 29, and the cam shaft 22 are synchronously rotated at a constant speed via the pins 36 and 37. As a result, a valve lift characteristic that matches the cam lift characteristic can be obtained.

On the other hand, in a low speed region of the engine, for example, the center Y of the annular disk 29 and the center X of the drive shaft 21 are connected via a hydraulic mechanism (not shown) as shown in FIGS. The position of the control ring 35 is controlled so that they are eccentric to each other. In this state, similarly to a kind of non-constant velocity shaft coupling, non-constant speed rotation in which the angular velocity of the annular disk 29 changes is achieved. As a result, the drive shaft 21 and the cam shaft 2
A phase difference corresponding to the amount of eccentricity between the two is given. As a result, the actual valve lift characteristics change. 2 to 5, the drive shaft 21 and the cam shaft 22 are not shown.

Further, in this embodiment, the axial thickness of the control ring 35 is slightly larger than that of the annular disk 29. That is, the side surface of the control ring 35 slightly projects outward from the side surfaces 29c and 29d of the annular disk 29. Therefore, including when the annular disc 29 is eccentric,
In order to prevent the control ring 35 from coming into contact with the first and second flange portions 27, 32, step portions 39, 40 are notched in the outer peripheral side portions of the respective flange portions 27, 32.
Thereby, the flange surface 27 of each of the flange portions 27, 32
Reference characters a and 32a have a substantially annular shape.

On the other hand, each side surface 29 of the annular disk 29 is
c and 29d form a continuous flat surface without unevenness from the inner peripheral edge to the outer peripheral edge of the annular disc 29, and the flange surfaces 27a and 32a are formed on the side surfaces 29c and 29d.
Are in surface contact with each other. The outer peripheral edge of the contact surface is the boundary between the step portions 39 and 40 or the side surface 29.
Although determined by the outer peripheral edges of c and 29d, when the annular disc 29 shown in FIGS.
It is kept on the outer peripheral side from the contact point P (see FIG. 1) on the inner peripheral side with 0, 33. In the state shown in FIGS. 4 and 5, the annular disc 2 is
9 is eccentric to the lower part of the drawing, whereas the second pin 37 is located on the lower part of the drawing, the second pin 37 is separated from the center X of the drive shaft 21. In the state, the step portion 4 serving as the outer peripheral end of the contact surface of the flange surface 32a
The boundary of 0 is located slightly on the outer peripheral side from the contact point on the inner peripheral side of the second pin 37 and overlaps in the range indicated by the symbol L. It should be noted that, if the first pin 36 is located at the lower part of the figure by rotating 180 degrees from the state of FIGS. 4 and 5, the same positional relationship between the first pin 36 and the flange surface 27a is also obtained in this state. Becomes

Next, the lubricating action in the structure of the above embodiment will be described. As described above, the lubricating oil is introduced from the lubricating oil passage 23 formed in the center of the drive shaft 21 through the oil hole 38 into the inner circumference of the annular disk 29. To be done. In addition, FIG.
In FIG. 5, the lubricating oil is indicated by the symbol O.
This lubricating oil tends to move toward the outer peripheral side by the centrifugal force caused by the rotation of the drive shaft 21 and the like, so that the engaging grooves 30, 33 from the inner peripheral surface 29b of the annular disk 29 as shown in FIGS.
Into the engaging grooves 30 and 33 in the radial direction. Here, both side edges of the engaging grooves 30 and 33 are formed on the respective flange surfaces 27a and 32a and the side surfaces 29c of the annular disk 29.
Since it is always in surface contact with 29d, it has a substantially partitioned shape, and most of the lubricating oil is guided into the engagement grooves 30, 33. Moreover, since the contact surfaces on both sides of the engagement grooves 30 and 33 are continuous to the position where the pins 36 and 37 are reached, the lubricating oil is reliably supplied to the pins 36 and 37.

Therefore, the pins 36 and 37 and the first and second engagement grooves 30 and 33 are always lubricated well. Also,
Part of the lubricating oil is the pins 36 and 37 and the holding holes 24 and 25.
It is also supplied to the mating surface with and the mating surface is surely lubricated.

In the above embodiment, the engaging grooves 30, 33 are used.
In addition to the both side edges, the flange surfaces 27a and 32a and the side surfaces 29c and 29d of the annular disk 29 are in wide annular contact, but this contact surface is at least engaged for guiding the lubricating oil. It suffices if they are on both sides of the mating grooves 30, 33.

Next, FIGS. 6 and 7 show different embodiments of the present invention. In this embodiment, the axial thickness T1 of the control ring 35 that rotatably holds the annular disc 29 is slightly smaller than the thickness T2 of the annular disc 29. Therefore, the step portions 39 and 40 of the respective flange portions 27 and 32 in the above-described embodiment are not provided in this embodiment, and the side surfaces 29c and 2 of the annular disk 29 are not provided.
The flange surfaces 27a and 32a that are in surface contact with 9d are continuous as the same plane up to the outer peripheral ends of the engagement grooves 30 and 33.

Therefore, as is apparent from FIGS. 6 and 7, even when the annular disk 29 is maximally eccentric, the flange surface 27 is extended to reach the pins 36 and 37.
Thus, a, 32a and the side surfaces 29c, 29d of the annular disk 29 make wide surface contact. Therefore, according to this embodiment, a larger eccentricity can be secured as compared with the above-mentioned embodiments. The control ring 35 includes the flange portion 27,
It suffices that only the inner peripheral side portion that overlaps 32 be made thin.

Next, FIGS. 8 and 9 show a further different embodiment of the present invention. In this example,
Oil grooves 41, 42 extending in the axial direction are formed along the fitting surfaces of the pins 36, 37 and the holding holes 24, 25.
Specifically, on the side surface of each of the pins 36 and 37, a flat surface portion along the surface orthogonal to the pair of flat surface portions 36a and 37a is formed over the entire length of the pins 36 and 37. Oil grooves 41, 42 are formed between the inner peripheral surfaces of the holding holes 24, 25.
Is configured. In particular, the oil grooves 41, 42 are provided in the direction toward the inner peripheral side of the annular disc 29 where the surface pressure of the fitting surface is low. In addition, in order to eliminate the directionality when assembling the pins 36 and 37 and to improve the workability, the flat portions serving as the oil grooves 41 and 42 may be formed at two places.

According to this embodiment, as described above, a part of the lubricating oil supplied to the pins 36 and 37 through the engagement grooves 30 and 33 is generated between the pins 36 and 37 and the holding holes 24 and 25. It is more smoothly guided in the space, and the fitting surface is surely lubricated.

In addition, the oil grooves 41 and 42 are provided in the holding oil 2
It is also possible to process the inner peripheral surface of 4,25.

Although not shown, the oil grooves 41,
An oil groove may be further formed along the radial direction on the side surfaces 29c and 29d of the annular disc 29 so as to connect the inner peripheral surface of the annular disc 29 with the inner periphery of the annular disc 29. Specifically, the oil groove reaching the oil groove 41 of the first pin 36 is on the side surface 29 d along the base end surface of the first pin 36, and the oil groove reaching the oil groove 42 of the second pin 37 is the second pin 37. Is formed on each of the side surfaces 29c along the base end surface of the.

[0033]

As is apparent from the above description, according to the intake / exhaust valve drive control device for an internal combustion engine according to the present invention, most of the lubricating oil introduced into the inner circumference of the annular disk is efficiently distributed to each pin. It can be supplied, and the space between the pin and the engagement groove can be reliably lubricated.

Further, when the pin is fitted in the holding hole as in the second aspect, the fitting surface is also lubricated at the same time.

Further, according to the structure of claim 3, the space between the pin and the holding hole is more surely lubricated.

Further, according to the structure of claim 4, it becomes easy to increase the eccentric amount of the annular disk while ensuring the reliable lubrication of the pin.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a main part of an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a main part when the annular disc is in a concentric position.

FIG. 3 is a front view when the annular disc is in the concentric position.

FIG. 4 is a sectional view of a main part when the annular disc is at the maximum eccentric position.

FIG. 5 is a front view when the annular disc is at the maximum eccentric position.

FIG. 6 is a cross-sectional view of a main part when the annular disc is at the maximum eccentric position, showing a different embodiment of the present invention.

FIG. 7 is a front view when the annular disc is at the maximum eccentric position.

FIG. 8 is a cross-sectional view of the main part when the annular disc is at the maximum eccentric position, showing a still further embodiment of the present invention.

FIG. 9 is a front view when the annular disc is at the maximum eccentric position.

FIG. 10 is a sectional view of a conventional intake / exhaust valve drive control device.

11 is a sectional view taken along the line DD of FIG.

FIG. 12 is a characteristic diagram showing a rotational phase difference characteristic and a valve lift characteristic of a conventional intake / exhaust valve drive control device.

[Explanation of symbols]

 21 ... Drive shaft 22 ... Cam shaft 24, 25 ... Holding hole 27 ... First flange part 32 ... Second flange part 29 ... Annular disk 30 ... First engaging groove 33 ... Second engaging groove 35 ... Control ring 36 ... First pin 37 ... Second pin 23 ... Lubricating oil passage

Front Page Continuation (72) Inventor Naofumi Ujuku 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Nissan Motor Co., Ltd. (72) Toshiji Yamada 2nd Takara-cho, Kanagawa-ku, Yokohama, Kanagawa Nissan Motor Co., Ltd. (72) Invention Akira Hidaka 1370 Onna, Atsugi City, Kanagawa Prefecture, within Unisia Jecs Co., Ltd.

Claims (4)

[Claims] 1. A drive shaft that rotates in synchronism with the rotation of an engine, and a cylindrical camshaft that has a cam that fits relative to the outer periphery of the drive shaft and that drives an intake and exhaust valve on the outer periphery. A first flange portion provided in a flange shape at an end portion of the camshaft and having a first engaging groove formed in the radial direction, and a first flange portion on the drive shaft side so as to face the first flange portion. A second flange portion which is provided and in which a second engaging groove is formed in the radial direction, an annular disc disposed between the flange portions, and opposite sides of the annular disc in opposite directions. A pair of pins protrudingly engaged in the respective engagement grooves of the flanges, a control ring for rotatably holding the annular disc and movable along the axis-perpendicular direction; Drive that moves the ring according to engine operating conditions In the intake / exhaust valve drive control device for an internal combustion engine, the structure is provided with lubricating oil introduced into the inner circumference of the annular disk through a lubricating oil passage inside the drive shaft, and the flange surface of each flange portion and the annular disk side surface. Contact surfaces with the engaging grooves are formed along both side edges of the engaging grooves, and the outer peripheral ends of the contact surfaces are closer to the outer peripheral side than the inner peripheral contact point between the pin and the engaging groove when the annular disc is maximally eccentric. An intake / exhaust valve drive control device for an internal combustion engine, which is extended to a position where 2. The intake / exhaust valve drive control device for an internal combustion engine according to claim 1, wherein the pin is rotatably fitted in a holding hole of an annular disk. 3. The pin comprises a cylindrical base portion that is rotatably fitted in the holding hole, and a tip portion that forms a parallel flat surface portion that engages with the engaging groove, and the holding hole. The intake / exhaust valve drive control device for an internal combustion engine according to claim 2, wherein an oil groove extending in the axial direction is formed along a fitting surface between the pin and the pin. 4. The flange surface is formed in the same plane up to the outer peripheral end of each engaging groove, and the axial thickness of the portion of the control ring that overlaps the outer peripheral portion of the flange portion is larger than that of the annular disc. The intake / exhaust valve drive control device for an internal combustion engine according to claim 1, wherein the intake / exhaust valve drive control device is formed thin.