JPH10220208A - Drive control device of suction and exhaust valve for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect peripheral edges of a first and a second flange sections from being engaged with an inner periphery of control ring and kept in locked state. SOLUTION: A cylindrical cam shaft is disposed at the outer periphery of a driving shaft, 21 rotating synchronously with an engine. An annular disk 29 is disposed between a first flange section 27 of a cam shaft and a second flange section 32 fixed on the driving shaft 21. The annular disk 29 is supported rotatably at the periphery with a movable control ring and connected to both of them by a pair of pins 36, 37. Even when the annular disk 29 is in the utmost eccentric position, the loci of the peripheral edges 27a, 32b of each flange are always kept inside of periphery of the annular disk 29 and does never contact with the control ring.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the opening and closing of an intake valve and an exhaust valve according to the operating state of an internal combustion engine by rotating a cylindrical camshaft arranged on the outer periphery of a drive shaft at an unequal speed relative to the drive shaft. The present invention relates to an intake and exhaust valve drive control device that variably controls a timing and an operation angle.

[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.
As described in JP-A-306-306 and JP-A-6-185321, there is one that applies the principle of a non-constant velocity shaft coupling.

FIG. 5 and FIG. 6 show this conventional intake / exhaust valve drive control device.
Is rotatably provided on the outer periphery of the drive shaft 1 and has an intake valve 16.
Is a cam that opens against the spring force of the valve spring 17. The cylindrical cam 2 includes a cam bearing bracket 3 and a flange 5 fixed to the drive shaft 1 via a key 4. Thus, the positioning in the axial direction is performed. A flange 7 having an engaging groove 6 is formed on one side of the cam 2, while an engaging groove 8 is also formed on the flange 5, and an annular ring is formed between the flanges 5 and 7. Disk 9 is interposed. The disc 9 is provided with pins 10 and 11 that engage with the engagement grooves 6 and 8 at opposing positions on both sides, and the outer periphery is rotatably held by a control ring 12. The control ring 12 has a protrusion 12 on the outer periphery.
a is supported by a support hole 13 on the cylinder head side via a, and a gear portion 12b located on the opposite side of the projection 12a is provided with a gear ring 1 on the outer periphery of the rocker shaft 14.
4a.

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. 5, the rotation centers of the drive shaft 1 and the disk 9 coincide with each other, so that the disk 9 is driven through the pin 11 and the engagement groove 8. The cam 2 rotates synchronously with the disk 9 at a constant speed via the pin 10 and the engagement 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, a kind of eccentric shaft coupling is constituted by the disk 9 having the engaging grooves 6 and 8 and the pins 10 and 11, and the cam 2 rotates following the drive shaft 1, but the rotation speeds of both are not. It becomes constant velocity. 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. Accordingly, the cam 2 generates a phase difference with respect to the drive shaft 1 as shown by a broken line or a dashed line in FIG. 7A, and as a result, as shown in FIG.
The valve lift characteristic shown by the solid line can be changed as shown by a broken line or a dashed line. The point P is a point where the rotational phase difference is always kept at zero.

[0006]

However, in the above-described conventional intake and exhaust valve drive control device, the annular disk 9
Are eccentric, the engagement grooves 6,
The movement trajectory of the outer peripheral ends 5 a, 7 a provided with the reference numeral 8 crosses the outer peripheral edge of the annular disk 9. That is, with the rotation of the drive shaft 1, the outer peripheral ends 5a,
7a moves from the inner peripheral side of the outer peripheral end of the annular disk 9 to the outer peripheral side, and conversely, moves from the outer peripheral side to the inner peripheral side. Therefore, if the relative positional relationship between the flange portions 5, 7 and the control ring 12 in the axial direction is not maintained with high accuracy, the outer peripheral ends 5a, 7a of the flange portions 5, 7 move toward the outer peripheral side. In addition, there is a possibility that the outer peripheral ends 5a and 7a and the control ring 12 are engaged with each other, so that a locked state is obtained.

[0007]

SUMMARY OF THE INVENTION Therefore, the present invention prevents the outer peripheral edge of the flange from crossing the outer peripheral edge of the annular disk. That is, the invention according to claim 1 is a cylindrical shape having a drive shaft that rotates in synchronization with the rotation of the engine, a cam rotatably fitted to the outer periphery of the drive shaft, and a cam for driving the intake and exhaust valves. And a first camshaft provided in a flange shape at an end of the camshaft and extending along the radial direction.
A first flange portion provided with an engagement groove, and a second flange portion provided on the drive shaft side to face the first flange portion and having a second engagement groove formed in a radial direction. A pair of annular discs disposed between the two flange portions, and a pair of annular discs projecting from opposite sides of the annular disc in opposite directions and respectively engaging in the respective engagement grooves of the two flange portions. A pin, a control ring fitted on the outer peripheral edge of the annular disk to rotatably hold the annular disk, and movable along the direction perpendicular to the axis; and a drive for moving the control ring according to the engine operating state. In the intake and exhaust valve drive control device for an internal combustion engine having the mechanism, the movement trajectory of the outer peripheral end where the engagement groove of the first and second flange portions is formed includes the maximum eccentricity of the control ring, Always located on the inner circumference side from the outer circumference of the annular disk It is characterized in Rukoto.

That is, even when the control ring is maximally eccentric, the outer peripheral ends of the first and second flange portions do not protrude to the outer peripheral side from the outer peripheral edge of the annular disk. Contact is avoided.

According to the second aspect of the present invention, the first and the second
The outer peripheral end portion of the flange portion is formed in an arc shape having a radius smaller than the radius of the outer peripheral edge of the annular disk. Accordingly, the length of the engagement groove can be maximized while keeping the outer peripheral ends of the first and second flange portions on the inner peripheral side of the outer peripheral edge of the annular disk.

[0010] In the invention of claim 3, contrary to claim 1,
The movement trajectory of the outer peripheral end where the engagement groove of the first and second flange portions is formed is always included, including the maximum eccentricity of the control ring.
It is characterized by being located on the outer peripheral side of the outer peripheral edge of the annular disk.

In this configuration, each flange portion is always located over both the annular disk and the control ring and does not retreat from the outer peripheral edge of the annular disk to the inner peripheral side. Of the control ring with the control ring is avoided.

Further, in the invention of claim 4, the first and the second
The outer peripheral end portion of the flange portion is formed in an arc shape having a radius larger than the radius of the outer peripheral edge of the annular disk. Thereby, the size of each flange portion can be made as small as possible while keeping the outer peripheral ends of the first and second flange portions on the outer peripheral side from the outer peripheral edge of the annular disk.

[0013]

According to the intake / exhaust valve drive control device for an internal combustion engine according to the present invention, the engagement between the flange portion and the control ring during eccentricity can be reliably prevented. In particular, according to the first aspect, since the flange portion and the control ring do not come into contact with each other, friction can be reduced and wear can be suppressed.
According to the second aspect, the length of the engagement groove can be as large as possible.

According to the third aspect of the present invention, the first and the second
Since the flange portion sandwiches the control ring from both sides, the axial movement of the control ring is regulated by the flange portion, and the contact surface with the annular disk outer peripheral surface is always kept constant,
Its local wear is prevented. And if comprised as Claim 4, the magnitude | size of each flange part can be made as small as possible, and interference with another component can be avoided.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 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. The drive shaft 21 extends in the front-rear direction of the engine and is formed in a hollow shape having a lubricating oil passage 23 at a central portion. 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 camshaft 22 is rotatably supported by a cam bearing at the upper end of a cylinder head (not shown), and has a cam at a predetermined position on the outer periphery for opening and closing an intake / exhaust valve. 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 FIG. 2, the first flange portion 27 is formed with an elongated rectangular first engagement groove 30 extending in the radial direction from the hollow portion.
9 has a flange surface 27a that is in sliding contact with one side surface 29c. The first engagement groove 30 is provided on the first flange portion 27.
The flange-shaped portion has an opening in a slit shape.

The sleeve 28 is disposed adjacent to the other end of the camshaft 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. The second flange portion 32 has a flange surface 32 a that slides on the other side surface 29 d of the annular disk 29, and, like the first flange portion 27, has an elongated rectangular second engagement groove extending in the radial direction. 33 are formed. The second
The engagement groove 33 is provided on the first flange 2 on the camshaft 22 side.
7 are arranged on the opposite side from the first engagement groove 30 by 180 °.

The annular disk 29 has a substantially donut 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. In this embodiment, the control ring 35
Is set slightly larger than the thickness of the annular disk 29. Further, holding holes 24 and 25 are formed through the annular disk 29 at opposing positions on diameter lines different from each other by 180 °, respectively.
25 has a first pin 3 engaging with each of the engagement grooves 30 and 33.
6, the second pins 37 are fitted and arranged. The pins 36 and 37 project in opposite directions to each other in the camshaft axial direction. A cylindrical base is rotatably fitted and supported in the holding holes 24 and 25 and projects from the surface of the annular disk 29. The engaging grooves 30 and 33
And two parallel flat portions 36a and 37a, which are in surface contact with the inner surfaces facing each other. The pin 3
The positioning of the shafts 6 and 37 in the axial direction depends on the protruding direction and the cylindrical surfaces of the pins 36 and 37 and the flat portions 36 a and 37.
a between steps 36b, 37b and flange surface 27
a, 32a, and in the retreat direction,
This is performed by abutment between the base end surfaces of the pins 36 and 37 penetrating the holding holes 24 and 25 and the flange surfaces 32a and 27a.

The inner peripheral surface 29b of the annular disk 29
To guide the lubricating oil from the lubricating oil passage 23 of the drive shaft 21 to the portion passing through the annular disc 29 of the drive shaft 21,
One or a plurality of oil holes 38 are formed along the radial direction.

The control ring 35 is configured to be movable in the direction of arrow Z along a plane perpendicular to the axial direction of the drive shaft 21, and is driven by a drive mechanism such as a hydraulic pressure (not shown) according to 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 predetermined operating conditions of the engine, for example, in a high-speed region, the center Y of the annular disk 29 and the drive shaft 2 are driven through a hydraulic mechanism (not shown) as shown in FIG.
The position of the control ring 35 is controlled such that the center X of one coincides with the center X. In this case, the annular disk 29 and the drive shaft 21
And the center of the camshaft 22 coincides with the center of the annular disk 29, so that there is no rotational phase difference between them. Therefore, the drive shaft 21,
The annular disk 29 and the camshaft 22 rotate synchronously at constant speed via the pins 36 and 37. As a result,
Valve lift characteristics in accordance with the cam lift characteristics 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 eccentric via a hydraulic mechanism (not shown) as shown in FIG. The position of the control ring 35 is controlled so as to be in the state. In this state, the angular velocity of the annular disc 29 changes at a non-uniform speed, similar to a type of non-uniform speed joint. Thus, a phase difference is provided between the drive shaft 21 and the camshaft 22 according to the amount of eccentricity between the two. As a result, the actual valve lift characteristics change.

In this embodiment, the maximum radial dimension of each of the flange portions 27 and 32 is the same as that of the annular disk 2.
9, the movement trajectory S1 of the outer peripheral ends 27b, 32b in the forming direction of the engagement grooves 30, 33 of the first and second flange portions 27, 32 is set to be relatively small. Including the maximum eccentricity of the control ring 35,
The annular disk 29 is always located on the inner peripheral side of the outer peripheral edge. And the first and second flange portions 2
The outer peripheral end portions 27b and 32b of the 7, 32 are formed in an arc shape having a radius smaller than the radius of the outer peripheral edge of the annular disk 29, specifically, in an arc shape along the movement locus S1.

Therefore, in the configuration of the above embodiment, even when the control ring 35 is maximally eccentric, the first and second
The outer peripheral ends 27b and 32b of the flange portions 27 and 32 do not protrude to the outer peripheral side than the outer peripheral surface 29a of the annular disk 29, and there is no possibility of contact with the control ring 35. Therefore, engagement between the inner peripheral surface of the control ring 35 and each of the flange portions 27 and 32 can be avoided. Moreover, the side of the control ring 35 and the flange 2
Since there is no contact with 7, 32, friction and abrasion due to contact between the two can be suppressed.

Since the outer peripheral ends 27b and 32b of the first and second flange portions 27 and 32 are formed in an arc shape along the movement locus S1, the first and second flange portions 27 and 32 are formed.
The length of the engagement grooves 30, 33 can be maximized while keeping the outer peripheral ends 27b, 32b of the 32 closer to the inner peripheral side than the outer peripheral edge of the annular disk 29.

Next, FIGS. 3 and 4 show different embodiments of the present invention. In this embodiment, the axial thickness of the annular disc 29 and the axial thickness of the control ring 35 are set to be equal to each other.
9c, 29d, 35a, and 35b are designed to have the same plane. In this embodiment, the maximum radial dimension of each of the flange portions 27 and 32 is set to be larger than the radius of the annular disk 29 in consideration of the maximum eccentric stroke of the annular disk 29. The movement trajectory S2 of the outer peripheral ends 27b and 32b in the direction in which the engagement grooves 30 and 33 are formed in the second flange portions 27 and 32 always indicates that the annular disc 29 is inclusive of the maximum eccentricity of the control ring 35.
It is located on the outer peripheral side of the outer peripheral edge. The outer peripheral end portions 27b and 32b of the first and second flange portions 27 and 32 are formed in an arc shape having a radius larger than the radius of the outer peripheral edge of the annular disk 29, specifically, along the movement locus S2. It is formed in an arc shape.

Therefore, in the configuration of the above embodiment, even when the control ring 35 is maximally eccentric, the first and second
The flange portions 27 and 32 are always located over both the annular disk 29 and the control ring 35, and the outer peripheral ends 27b and 32b do not retreat from the outer peripheral edge of the annular disk 29 to the inner peripheral side. Therefore, the outer peripheral ends 27b and 32b are
The engagement between the inner peripheral surface of the control ring 35 and each of the flange portions 27 and 32 caused by crossing the outer peripheral surface 29a can be avoided. Moreover, in this embodiment, the control ring 35 is
7 and 32, the movement in the axial direction is restricted, so that the contact surface between the outer peripheral surface 29 a of the annular disk 29 and the inner peripheral surface of the control ring 35 is always kept constant, and its local wear is reduced. Is prevented.

Since the outer peripheral ends 27b and 32b of the first and second flange portions 27 and 32 are formed in an arc shape along the movement locus S2, the first and second flange portions 27 and 32 are formed.
32, while keeping the outer peripheral ends 27b, 32b of the flanges 27, 32b outside the outer peripheral edge of the annular disk 29 at all times.
Can be made as small as possible, and interference with other components can be avoided.

[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 front view when the annular disk is at a maximum eccentric position.

FIG. 3 is a sectional view of a main part showing a different embodiment of the present invention.

FIG. 4 is a front view when the annular disk is at a maximum eccentric position.

FIG. 5 is a sectional view of a conventional intake and exhaust valve drive control device.

FIG. 6 is a sectional view taken along line DD of FIG. 5;

FIG. 7 is a characteristic diagram showing a rotational phase difference characteristic and a valve lift characteristic of this type of intake / exhaust valve drive control device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 ... Drive shaft 22 ... Camshaft 24, 25 ... Holding hole 27 ... 1st flange part 32 ... 2nd flange part 29 ... Annular disk 30 ... 1st engagement groove 33 ... 2nd engagement groove 35 ... Control ring 36 ... 1st pin 37 ... 2nd pin

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masaharu Saito 1370 Onna, Atsugi-shi, Kanagawa Prefecture

Claims (4)

[Claims] A drive shaft that rotates in synchronization with the rotation of the engine; and a cylindrical camshaft that is rotatably fitted to the outer periphery of the drive shaft and has a cam that drives a suction 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 engagement groove formed in a radial direction; and a first flange portion facing the first flange portion on the drive shaft side. A second flange portion provided with a second engagement groove along the radial direction, an annular disk disposed between the two flange portions, and opposite sides of the annular disk in opposite directions. A pair of pins that are protruded and respectively engage in the respective engagement grooves of the two flange portions, and are fitted to the outer peripheral edge of the annular disk to rotatably hold the annular disk, and in a direction perpendicular to the axis. A control ring that can move along A drive mechanism that moves in accordance with an operating state; and a drive control device for an intake and exhaust valve of an internal combustion engine, comprising: Always including the maximum eccentricity of the ring,
An intake / exhaust valve drive control device for an internal combustion engine, which is located on an inner peripheral side of an outer peripheral edge of an annular disk. 2. The internal combustion engine according to claim 1, wherein the outer peripheral end portions of the first and second flange portions are formed in an arc shape having a radius smaller than a radius of an outer peripheral edge of the annular disk. Engine intake and exhaust valve drive control device. 3. A drive shaft that rotates in synchronization with rotation of the engine, and a cylindrical camshaft that is fitted to the outer periphery of the drive shaft so as to be relatively rotatable and has a cam that drives a suction 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 engagement groove formed in a radial direction; and a first flange portion facing the first flange portion on the drive shaft side. A second flange portion provided with a second engagement groove along the radial direction, an annular disk disposed between the two flange portions, and opposite sides of the annular disk in opposite directions. A pair of pins that are protruded and respectively engage in the respective engagement grooves of the two flange portions, and are fitted to the outer peripheral edge of the annular disk to rotatably hold the annular disk, and in a direction perpendicular to the axis. A control ring that can move along A drive mechanism that moves in accordance with an operating state; and a drive control device for an intake and exhaust valve of an internal combustion engine, comprising: Always including the maximum eccentricity of the ring,
An intake / exhaust valve drive control device for an internal combustion engine, which is located on an outer peripheral side of an outer peripheral edge of an annular disk. 4. The internal combustion engine according to claim 1, wherein the outer peripheral end portions of the first and second flange portions are formed in an arc shape having a radius larger than the radius of the outer peripheral edge of the annular disk. Engine intake and exhaust valve drive control device.