JP2004270556A - Valve timing control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately form a radial groove for guiding a movable guide part without causing the sudden rise of a manufacturing cost. <P>SOLUTION: A drive ring 5 is provided with the radial groove 9, and an intermediate rotation body 19 rotationally operated from the outside is provided with a spiral groove 16. The proximal end of a link 12 with the tip parts engaged straddling the radial groove 9 and the spiral groove 16 is connected to a lever 10 of a driven shaft member 3. In such a device, the radial groove 9 is composed of a first block 41 having a radial hole 44 of elongated hole shape, and a second block 43 jointed to the first block 41 to block the bottom part of the radial hole 44. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a valve timing control device for an internal combustion engine that variably controls the opening / closing timing of an intake-side or exhaust-side engine valve of the internal combustion engine in accordance with an operating state.
[0002]
[Prior art]
The following has been devised as this type of valve timing control device (see Patent Document 1).
[0003]
In this valve timing control device, a housing (driving rotating body) linked to a crankshaft via a timing chain or the like is rotatably assembled to an end of a camshaft, and a radial groove formed on an inner end surface of the housing. A movable guide portion is slidably engaged in the radial direction and supported, and a driven shaft member (a driven rotating body) having a lever protruding outward in the radial direction is bolted to an end of the camshaft to be movable. The guide and the lever of the driven shaft member are pivotally connected by a link. An intermediate rotating body having a spiral guide is provided at a position facing the radial groove so as to be relatively rotatable with respect to the housing and the driven shaft member. The guide guide is engaged with the guide. The intermediate rotating body is biased by a spring (torsion spring) as biasing means toward the side that advances rotation with respect to the housing, and appropriately receives a force on the side that delays rotation by an electromagnetic brake as braking means. It has become.
[0004]
In this device, when the electromagnetic brake is in the OFF state, the intermediate rotating body is located at the initial position with respect to the housing under the urging force of the mainspring spring, and the movable guide portion meshing with the spiral guide extends radially outward. It is displaced to the maximum and causes a link to cause the assembling angle between the housing and the driven shaft member to be the angle position of the most retarded phase (hereinafter, referred to as the “most retarded position”) or the angle position of the most advanced phase (hereinafter, referred to as This is called the "most advanced position." Then, when the electromagnetic brake is turned ON from this state, the intermediate rotating body is decelerated and relatively rotates with respect to the delay side with respect to the housing. As a result, the movable guide portion meshing with the spiral guide is displaced radially inward, The assembling angle of the housing and the driven shaft member is changed to the most advanced position or the most retarded position by gradually tilting the link that has been caused up to now.
[0005]
[Patent Document 1]
JP 2002-227616 A
[Problems to be solved by the invention]
However, in this conventional valve timing control device, since the radial groove is formed by forming a groove on the side wall of the plate-shaped housing, it is difficult to increase the dimensional accuracy of the radial groove, and the dimensional accuracy is increased. If this is attempted, there is a problem in that the production cost will rise significantly.
[0007]
Accordingly, an object of the present invention is to provide a valve timing control device for an internal combustion engine that can accurately form a radial groove for guiding a movable guide portion without increasing manufacturing costs. .
[0008]
[Means for Solving the Problems]
As means for solving the above-mentioned problems, the invention of this application is based on a first block having a long hole-shaped radial hole, and a second block which is joined to the first block and closes the bottom of the radial hole. It was made up of blocks.
[0009]
In the case of the present invention, since the radial hole on the first block side completely penetrates the block, the inner surface can be machined with high accuracy without requiring difficult groove machining. Then, since the radial groove only needs to be joined to the first block processed in this way, the second block can be formed accurately without incurring a rise in manufacturing cost.
[0010]
In addition, since the bottom of the radial groove is formed by the second block joined to the first block, the corner of the groove bottom is formed in an arcuate surface as in the conventional one in which the radial groove is formed by groove processing. Never be. Therefore, there is no fear that the movable guide portion which is guided and engaged with the radial groove is caught on the circular arc surface of the corner at the bottom of the groove, which reduces the sliding gap between the movable guide portion and the radial groove, and has a loose play. Occurrence can be suppressed.
[0011]
It is preferable that one of the first and second blocks is fitted to the other. In this case, the displacement of the two blocks in the radial direction can be prevented, so that the assembling work can be easily performed.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of the invention of this application will be described based on the drawings.
[0013]
In this embodiment, the valve timing control device according to the invention of this application is applied to a valve train on the intake side of an internal combustion engine. However, the valve timing control device can be similarly applied to a valve train on the exhaust side.
[0014]
The valve timing control device includes a driven shaft member 3 (a driven rotary member) coupled to a front end of a camshaft 1 on the intake side of the internal combustion engine, as shown in FIG. A drive ring 5 (drive rotator) assembled so as to be relatively rotatable and linked to a crankshaft (not shown) via a chain (not shown), and a front side of the drive ring 5 (in FIG. 1) (A left side), an assembling angle operating mechanism 6 for relatively rotating the drive ring 5 and the driven shaft member 3 to operate an assembling angle of both, and an operation for applying an operating force to the assembling angle operating mechanism 6 And a force applying means 7.
[0015]
The drive ring 5 includes a substantially disk-shaped first block 41 having a large-diameter first sprocket 40 on the outer circumference and a substantially cylindrical second block 43 having a small-diameter second sprocket 42 on the rear end circumference. The blocks are connected to each other by screws or the like. As shown in FIGS. 2 and 3, three radial grooves 9 are formed on the front surface of the drive ring 5 (the surface opposite to the camshaft 1). The first sprocket 40 is for inputting power from a crankshaft, and the sprocket 42 on the second block 43 side is for transmitting power to an exhaust camshaft (not shown). .
[0016]
As shown in FIGS. 1 and 4, the first block 41 has three elongated radial holes 44 extending substantially in the radial direction. The front end face of the block 42 is in contact. The front end surface of the second block 42 is formed flat, and closes the bottom surface of each of the radial holes 44 in a state of contacting the back surface of the first block 41. Each radial hole 44 of the first block 41 forms the aforementioned three radial grooves 9 together with the front end face of the second block 42. As shown in FIGS. 1 and 5, a circular recess 45 is formed on the back side of the first block 41, and the front end of the first block 41 is fitted into the recess 45.
[0017]
Further, as shown in FIG. 1, the driven shaft member 3 has an enlarged diameter portion formed on an outer periphery of a base portion which is abutted against a front end portion of the camshaft 1, and has an outer peripheral portion located forward of the enlarged diameter portion. Three levers 10 protruding radially from the surface are integrally formed, and are connected to the camshaft 1 by bolts 11 penetrating the shaft core. A base end of a link 12 is pivotally connected to each lever 10 by a pin 13, and a column-shaped projection 14 slidably engaged with each of the radial grooves 9 is integrally formed at a distal end of each link 12. Is formed.
[0018]
Each link 12 is connected to the driven shaft member 3 via the pin 13 in a state where the protrusions 14 are engaged with the corresponding radial grooves 9. When displaced along 9, the drive ring 5 and the driven shaft member 3 rotate relative to each other by the action of the link 12 in a direction and an angle corresponding to the displacement of the projection 14.
[0019]
A receiving hole 15 is formed at the distal end of each link 12 and opens forward in the axial direction. The receiving hole 15 has an engaging pin 17 that engages with a spiral groove 16 (a spiral guide) described later. And a coil spring 18 for urging the engagement pin 17 forward (toward the spiral groove 16). In the case of this embodiment, a movable guide portion that can be displaced in the radial direction is configured by the projecting portion 14 at the distal end of the link 12, the engagement pin 17, the coil spring 18, and the like.
[0020]
On the other hand, an intermediate rotating body 19 having a disk-shaped flange wall is rotatably supported via a bearing 20 in front of the driven shaft member 3 with respect to the projecting position of the lever 10. The above-described spiral groove 16 having a semicircular cross section is formed on the rear surface side of the flange wall of the intermediate rotating body 19, and the engaging pin 17 at the tip of each link 12 is rotatably guided by the spiral groove 16. Have been combined. The spiral of the spiral groove 16 is formed so that the diameter gradually decreases along the engine rotation direction R. Therefore, when the intermediate rotating body 19 relatively rotates in the delay direction with respect to the drive ring 5 in a state in which the engagement pin 17 at the tip of each link 12 is engaged with the spiral groove 16, the tip of the link 12 becomes the radial groove 9. While being guided by the spiral shape of the spiral groove 16 and moving radially inward, conversely, when the intermediate rotating body 19 is relatively displaced in the advancing direction, it moves radially outward.
[0021]
The assembling angle operating mechanism 6 includes the radial groove 9, the link 12, the protrusion 14, the engaging pin 17, the lever 10, the intermediate rotating body 19, the spiral groove 16, and the like of the drive ring 5 described above. When the relative rotation operation force with respect to the drive ring 5 is input to the intermediate rotating body 19 from the operation force applying means 7 described later, the assembly angle operation mechanism 6 applies the operation force to the spiral groove 16 and the engagement pin. The distal end of the link 12 is displaced in the radial direction through the engaging portion 17, and at this time, the link 12 swings, and the drive ring 5 and the driven shaft member 3 are relatively rotated according to the swing amount.
[0022]
On the other hand, the operating force applying means 7 includes a mainspring 21 serving as an urging means for urging the intermediate rotating body 19 against the drive ring 5 in the engine rotation direction R, and an A hysteresis brake 2 as an electromagnetic brake for relatively rotating in a direction opposite to the rotation direction R, such that the intermediate rotating body 19 is rotated by the balance between the urging force of the mainspring 21 and the braking force of the hysteresis brake 2. Has become.
[0023]
The mainspring 21 has an outer peripheral end coupled to the cylindrical member 8 fixed to the drive ring 5, and an inner peripheral end coupled to a cylindrical base of the intermediate rotating body 19.
[0024]
The hysteresis brake 2 includes an electromagnetic coil 22 as a braking force generator supported and fixed to a VTC cover (not shown) that is a non-rotating member, and a braked rotating body 23 that receives a braking force generated by a magnetic field generated by the electromagnetic coil 22. The braked rotating body 23 is connected to the intermediate rotating body 19 via a rubber bush 24 and a connecting pin 25.
[0025]
The electromagnetic coil 22 has a coil block 26 whose main element is a coil winding that generates a magnetic field when energized, and a yoke 27 that is arranged around the coil block 26 and induces magnetic flux. Are provided with inner pole teeth 29 and outer pole teeth 30 which are arranged to face each other with an annular gap therebetween. A plurality of tooth surfaces are arranged on these pole teeth 29, 30 along the circumferential direction. The tooth surfaces of the bipolar teeth 29 and 30 are arranged offset from each other in the circumferential direction, and when the coil winding of the coil block 26 is energized, the mating electrodes having the offset positional relationship between the bipolar teeth 29 and 30 are arranged. A magnetic field directed toward the tooth surface is generated.
[0026]
The braked rotating body 23 has a cylindrical hysteresis ring 31 inserted and disposed between the pole teeth 29 and 30 in a non-contact state, and an outer peripheral end portion integrally connected to the hysteresis ring 31, A disk-shaped plate-shaped member 33 having a shaft end 32 connected to the peripheral end thereof. The shaft 32 connected to the plate-shaped member 33 is rotatably supported by the yoke 27 via a bearing 34. I have. Therefore, the braked rotating body 23 is always supported by the electromagnetic coil 22, thereby suppressing swinging and radial vibration during rotation.
[0027]
The hysteresis ring 31 is made of a hysteresis material having a magnetic hysteresis characteristic. A shift is caused. The hysteresis brake 2 generates a braking force due to this shift.
[0028]
Since the valve timing control device is configured as described above, when changing the rotation phase of the crankshaft and the camshaft 1 (opening / closing timing of the engine valve) to the most advanced side, an appropriate current is applied to the hysteresis brake 2. By energizing, a braking force against the force of the mainspring 21 is transmitted from the plate member 33 to the intermediate rotating body 19 via the rubber bush 24 and the connecting pin 25. As a result, the intermediate rotating body 19 rotates in the opposite direction with respect to the drive ring 5, whereby the engaging pin 17 at the tip of the link 12 is guided to the spiral groove 16, and the tip of the link 12 is displaced radially inward. At this time, as shown in FIG. 3, the operation angle of the link 12 changes the assembly angle between the drive ring 5 and the driven shaft member 3 to the most advanced position.
[0029]
When the rotation phase of the crankshaft and the camshaft 1 (opening / closing timing of the engine valve) is changed to the most retarded side, the energizing current of the hysteresis brake 2 is turned off or weakened, so that the intermediate rotating body 19 is turned off. It is rotated in the engine rotation direction by the force of the mainspring 21. Then, the leading end of the link 12 is displaced radially outward by the guide of the engaging pin 17 by the spiral groove 16, and at this time, the combination of the drive ring 5 and the driven shaft member 3 by the action of the link 12 as shown in FIG. The angle is changed to the most retarded position.
[0030]
In this valve timing control device, the radial groove 9 for guiding the projecting portion 14 at the tip of the link 12 is closed by the first block 41 having the radial hole 44 and the bottom of the radial hole 44 of the first block 41. With the second block 43, the radial groove 9 can be easily and accurately formed. In other words, the radial hole 44 of the first block 41 is a hole that completely penetrates the wall, and it is not necessary to control the processing depth or the like as in the case of processing a groove. Work can be easily carried out. The bottom surface of the radial groove 9 is formed with high accuracy when the first block 41 and the second block 43 are joined together by processing the front end surface of the second block 43 with high precision. Therefore, in this device, low-cost manufacturing can be realized without lowering the function.
[0031]
Further, in the case of this device, since the bottom surface of the radial groove 9 is formed by the front end face of the second block 43 as described above, the connecting corner between the side wall and the bottom surface of the radial groove 9 can be formed substantially at a right angle. It is not possible to form an arcuate surface in the connecting corner as in the case of performing groove processing. Therefore, there is no fear that the projecting portion 14 at the tip of the link 12 is caught on the circular arc surface, so that the sliding gap between the projecting portion 14 and the radial groove 9 is sufficiently narrowed, and the occurrence of dulling at this portion is reliably suppressed. be able to.
[0032]
Furthermore, in the device of this embodiment, a circular concave portion 45 is formed on the back surface of the first block 41, and the front end of the second block 43 is fitted into the concave portion 45. At the time of connection, the displacement of the two in the radial direction can be reliably prevented. Therefore, the joining operation of the two blocks 41 and 43 can be performed efficiently.
[0033]
Next, inventions other than those described in the claims that can be understood from the above embodiments will be described below together with their operational effects.
[0034]
(A) The valve timing control device for an internal combustion engine according to claim 1 or 2, wherein a sprocket is formed in the first block.
[0035]
In this case, it is necessary to form the entire first block with a hard material in order to reliably transmit power with the sprocket. Therefore, if the entire first block is formed with a hard material, the strength of the inner surface of the radial hole is reduced. And the movable guide member can be guided stably for a long period of time.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention.
FIG. 2 is an exemplary sectional view of the same embodiment taken along line AA of FIG. 1;
FIG. 3 is an exemplary sectional view corresponding to FIG. 2 showing an operation state of the embodiment;
FIG. 4 is an exploded perspective view showing the same embodiment.
FIG. 5 is a rear view showing the embodiment.
[Explanation of symbols]
1: camshaft 3: driven shaft member (driven rotator)
5. Drive ring (drive rotator)
7 Operating force applying means 9 Radial groove 12 Link 14 Projection (movable guide)
16: spiral groove (spiral guide)
17 ... engagement pin (movable guide)
18 ... Coil spring (movable guide)
19 intermediate rotating body 41 first block 43 second block 44 radial hole

Claims (2)

A driven rotating body that is rotationally driven by a crankshaft of an internal combustion engine, a camshaft or a separate member coupled to the shaft, and a driven rotating body to which power is transmitted from the driven rotating body; A radial groove provided on any one of the rotating bodies, and an intermediate part provided with a spiral guide on a surface facing the radial groove and provided rotatably with respect to the driving rotating body and the driven rotating body. A rotator, a movable guide portion displaceably engaged with the radial groove and the spiral guide, a portion separated from a rotation center of one of the driving rotator and the driven rotator, and the movable guide. And a link that swingably connects the unit and an operating force applying unit that applies a relative rotational operating force to the intermediate rotating body with respect to a driving rotating body and a driven rotating body,
By rotating the intermediate rotating body with respect to the driving rotating body and the driven rotating body by the operating force applying means, the movable guide portion engaged with the spiral guide is radially displaced along the radial groove. A valve timing control device for an internal combustion engine that converts the displacement into a relative rotation between a driving rotor and a driven rotor via the link,
The internal combustion engine, wherein the radial groove is constituted by a first block having a long hole-shaped radial hole and a second block joined to the first block to close a bottom of the radial hole. Valve timing control device. The valve timing control device for an internal combustion engine according to claim 1, wherein one of the first and second blocks is fitted to the other.

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