JP2004270606A - Valve timing control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maintain constant spacing and facing attitudes between a braking force generating part and a braking force receiving part irrespective of the tip part variation of a camshaft. <P>SOLUTION: An electromagnetic coil 22 is fixed to a non-rotating member, and a braked rotation body 23 is supported to the electromagnetic coil 22 through a bearing 34. The braked rotation body 23 is provided with a projecting piece 35, and an intermediate rotation body 19 of an assembly angle operating mechanism 6 is provided with a columnar protrusion 37 so as to be on the same rotation track as the projecting piece 35. A rubber bush 36 is attached to the projecting piece 35, and the projecting piece 35 with the bush 36 attached is allowed to abut on the columnar protrusion 37 by the rotation of the intermediate rotation body 19. Variation on the intermediate rotation body 19 side is not easily transmitted to the braked rotation body 23 side, and the deflection of the braked rotation body 23 is positively restrained by the bearing 34. <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 device, a housing (drive rotating body) linked to a crankshaft via a timing chain or the like is rotatably assembled to an end of a camshaft, and a movable guide is formed on a radial guide formed on an inner end surface of the housing. A lever shaft (followed rotating body) having a lever protruding outward in the radial direction is bolted to an end of the camshaft, and the movable guide portion and the lever The shaft lever and the shaft are pivotally connected by a link. An intermediate rotating body having a spiral guide is provided at a position facing the radial guide so as to be rotatable relative to the housing and the lever shaft, and is provided at one end of the movable guide portion in the axial direction. A plurality of projecting substantially arc-shaped projections are guided and engaged with the spiral guide. The intermediate rotator is biased by a spring to the side that advances the rotation with respect to the housing, and receives an appropriate force on the side that delays the rotation by an electromagnetic brake.
[0004]
In the case of 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 which meshes with the spiral guide with a ridge is provided. It is maximally displaced radially outward, causing a link to maintain the assembly angle between the housing and the camshaft at the most retarded position or 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 between the housing and the camshaft is changed to the most advanced position or the most retarded position by gradually tilting the link that has been caused so far.
[0005]
In the electromagnetic brake, a braking force generating portion composed of a coil winding and a yoke is fixed to a non-rotating member such as a VTC cover, and an intermediate rotating body facing the end surface of the yoke serves as a braking force receiving portion for directly receiving the braking force. ing.
[0006]
[Patent Document 1]
JP 2001-41013 A
[Problems to be solved by the invention]
However, in the case of the above-described conventional valve timing control device, since the positional relationship between the braking force generating portion of the electromagnetic brake and the braking force receiving portion (intermediate rotating body) is not constrained to each other, the cam is not moved with the engine operation. If the tip of the shaft fluctuates in the bending direction or the rotation direction, the fluctuation may change the distance between the braking force generating unit and the braking force receiving unit and the facing position, and may not be able to obtain a desired braking force.
[0008]
Therefore, the invention of this application enables to always maintain a stable operation performance by maintaining a constant distance or facing position between the braking force generating unit and the braking force receiving unit irrespective of the fluctuation of the tip of the camshaft. It is an object of the present invention to provide a valve timing control device for an internal combustion engine that can perform the above.
[0009]
[Means for Solving the Problems]
As means for solving the above-described problems, the invention of this application is to fix a braking force generating portion of an electromagnetic brake to a non-rotating member and to connect a braking force receiving portion of the electromagnetic brake to the braking force generating portion via a bearing. The braking force receiving part and the intermediate rotating body are provided with contacting parts that come into contact with each other on the same rotation track so that they can be separated from each other, and the two contacting parts are rotated by rotation of the intermediate rotating body. They were brought into contact with each other.
[0010]
In the case of the present invention, since the braking force receiving portion is supported by the braking force generating portion via the bearing, the distance between the two is kept constant regardless of the input of the external force. In addition, the braking force is transmitted from the braking force receiving portion to the intermediate rotating body by contact between the contact portions on the same rotation track, but the braking force receiving portion and the intermediate rotating body are completely restrained from each other. Therefore, the fluctuation torque of the camshaft and the like are less likely to be transmitted to the braking force receiving portion via the intermediate rotating body. Therefore, from these, it is possible to always maintain the distance between the braking force generating unit and the braking force receiving unit and the facing posture constant, and as a result, the operability of the valve timing control device is stabilized.
[0011]
Further, in the case of the present invention, it is necessary to specially connect the braking force receiving portion and the intermediate rotating body only by arranging the contact portion between the braking force receiving portion and the intermediate rotating body so as to be located on the same rotation track. Therefore, there is an advantage that the assembling work is facilitated.
[0012]
In addition, it is preferable that the abutting portion on at least one side of the braking force receiving portion and the intermediate rotating body is formed of a plane extending in the radial direction and the axial direction. In this case, since at least one contact portion is formed of a plane orthogonal to the rotation direction, it is possible to reliably transmit the braking force between the two.
[0013]
An elastic body may be provided at a contact portion of at least one of the braking force receiving portion and the intermediate rotating body. In this case, it is possible to buffer the vibration and the shock caused by the sudden contact between the contact portions by the elastic body.
[0014]
Further, it is preferable that the elastic body is provided so as to cover both front and rear surfaces in the rotational direction of the contact portion. In this case, the one contact portion is rotated back and forth in the rotational direction with respect to the other contact portion. No matter from which side, the cushioning action of the elastic body works reliably. Therefore, generation of fluttering sound due to contact between the contact portions can be reliably suppressed.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of the invention of this application will be described based on the drawings.
[0016]
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.
[0017]
The valve timing control device includes a driven shaft member 3 (driven rotating body) coupled to a front end of a camshaft on the intake side of the internal combustion engine, as shown in FIG. A drive ring 5 (drive rotator) that is rotatably assembled and linked to a crankshaft (not shown) via a chain (not shown), and a front side (left side in FIG. 1) of the drive ring 5 ), 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 the both, and an operating force for applying an operating force to the assembling angle operating mechanism 6 Application means 7.
[0018]
The drive ring 5 has a drive input sprocket 4 formed on the outer periphery thereof, and three radial grooves 9 formed on its front side (opposite side to the camshaft) as shown in FIGS. ing.
[0019]
As shown in FIG. 1, the driven shaft member 3 has a large-diameter portion formed on an outer periphery on a base side that abuts on a front end portion of a camshaft (not shown). Also, three levers 10 protruding radially are formed integrally on the outer peripheral surface on the front side, and are connected to the camshaft 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.
[0020]
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.
[0021]
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.
[0022]
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.
[0023]
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.
[0024]
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.
[0025]
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.
[0026]
The hysteresis brake 2 includes an electromagnetic coil 22 serving as a braking force generator supported and fixed to a VTC cover (not shown), which is a non-rotating member, and a braked rotating body 23 (braking force) that receives a braking force generated by a magnetic field generated by the electromagnetic coil 22. The braked rotating body 23 is linked to the intermediate rotating body 19 via a contact mechanism described later.
[0027]
The electromagnetic coil 22 includes a coil winding 26 that generates a magnetic field when energized, and a yoke 27 that is arranged around the coil winding 26 and induces a magnetic flux. The inner pole teeth 29 and the outer pole teeth 30 that are arranged to face each other with the. 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, 30 are arranged offset from each other in the circumferential direction, and when the coil winding 26 is energized, the tooth surfaces of the bipolar teeth 29, 30 have an offset positional relationship with each other. A heading magnetic field is generated.
[0028]
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.
[0029]
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.
[0030]
Meanwhile, as shown in FIGS. 4 to 7, a pair of protruding pieces 35, 35 protruding toward the intermediate rotating body 19 are formed on the plate-shaped member 33 by cutting and raising. These protruding pieces 35 are symmetrically arranged at positions 180 ° apart from each other in the circumferential direction, and are formed such that the flat cut-and-raised surface of each protruding piece 35 extends in the radial direction and the axial direction. A substantially fan-shaped rubber bush 36 (elastic body) is fitted and fixed to these protruding pieces 35. The front and rear surfaces of the rubber bush 36 in the rotational direction are flat surfaces, and are formed to extend in the radial and axial directions similarly to the protruding pieces 35.
[0031]
On the other hand, the intermediate rotating body 19 is integrally formed with a pair of columnar projections 37 extending in the direction of the plate-like member 33 and having a substantially fan-shaped cross section. These columnar projections 37 are provided symmetrically at positions spaced apart by 180 ° in the circumferential direction, and are arranged on the same rotation path as the two projecting pieces 35 of the plate-shaped member 33. Therefore, when the intermediate rotating body 19 rotates following the drive ring 5, the columnar projection 37 contacts the protruding piece 35 via the rubber bush 36, and the intermediate rotating body 19 and the braked rotating body 23 are brought into contact with each other. Rotate them together. The columnar protrusion 37, the protrusion 35 and the rubber bush 36 constitute the above-mentioned contact mechanism. In this specification, the phrase “arranged on the same rotational trajectory” does not necessarily mean that the rotational trajectories at the centers of the two completely coincide with each other. We use it in the sense that we do. In this embodiment, the protruding piece 35 and the columnar protrusion 37 constitute each contact portion in the present invention.
[0032]
Since this valve timing control device is configured as described above, when changing the rotation phase of the crankshaft and the camshaft (opening / closing timing of the engine valve) to the most advanced side, an appropriate current is supplied to the hysteresis brake 2. By doing so, a braking force against the force of the mainspring spring 21 is transmitted from the braked rotating body 23 to the intermediate rotating body 19 via the contact portion between the projecting piece 35 and the columnar projection 37. 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.
[0033]
When the rotation phase of the crankshaft and the camshaft (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 rotated. It is rotated in the engine rotation direction by the force of the spring 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.
[0034]
By the way, in this valve timing control device, since the braked rotating body 23 receiving the braking force of the hysteresis brake 2 is rotatably supported by the yoke 27 of the electromagnetic coil 22 via the bearing 34, the pole teeth of the electromagnetic coil 22 The gaps and postures between the hysteresis rings 31 and 29, 30 are always kept constant. Since the braked rotating body 23 is linked to the intermediate rotating body 19 through the abutting portion of the protruding piece 35 and the columnar projection 37, the fluctuation torque and the swing of the camshaft are reduced by the braked rotating body 23 side. Is hardly transmitted to That is, since the protruding piece 35 (accurately, the rubber bush 36 portion) and the columnar protrusion 37 are linked only by abutment on a plane orthogonal to the rotation direction, torque in the anti-braking direction, vibration in the radial direction, and vibration Motion and the like are prevented from being transmitted between the abutting portions. Therefore, the hysteresis brake 2 can always generate a stable braking torque.
[0035]
In this apparatus, since the rubber bush 36 is fitted to the projection 35 and the projection 35 is brought into contact with the columnar projection 37 via the rubber bush 36, the projection 35 and the columnar projection 37 are in contact with each other. The impact and vibration can be buffered by the rubber bush 36. Further, since the rubber bush 36 covers the front and rear surfaces of the protruding piece 35 in the rotation direction, and can reduce the collision impact from both front and rear sides, the rubber bush 36 is not suitable for the case where the braked rotating body 23 is fluttered in the front and rear directions in the rotation direction. However, generation of fluttering sound can be reliably suppressed.
[0036]
Further, in the case of this device, the projecting piece 35 and the columnar projection 37 are arranged on the same rotation track, and the projecting piece 35 and the columnar projection 37 are brought into contact with each other by the rotation of the intermediate rotating body 19. As compared with the case where the intermediate member 23 and the intermediate rotating body 19 are connected in a constrained state, there is an advantage that the assembling becomes easier and the manufacturing cost can be reduced.
[0037]
Further, in the case of this embodiment, since the protruding piece 35 (rubber bush 36) and the columnar protrusion 37 abut on each other in a plane perpendicular to the rotation direction, the braking torque can be reliably transmitted between the abutting surfaces. There is an advantage that the contact surface pressure between the two can be reduced. However, a certain effect can be obtained even if only one of the protruding piece 35 (rubber bush 36) and the columnar protrusion 37 is formed on a plane perpendicular to the rotation direction.
[0038]
Furthermore, in this embodiment, two projections 35 and two columnar projections 37 are provided, but one or three or more may be provided. However, providing a plurality of each of them makes it possible to further narrow the fluttering range in the rotation direction of the braked rotating body 23 and to improve the operation responsiveness of the device.
[0039]
The embodiments of the invention of this application are not limited to those described above. For example, a friction contact type brake may be used instead of the hysteresis brake 2 for the electromagnetic brake. Also, as the assembling angle operating mechanism 6, various other mechanisms can be adopted as long as the driving rotator and the driven rotator are relatively rotated by the rotation operation of the intermediate rotator 19.
[0040]
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.
[0041]
(B) The valve timing control device for an internal combustion engine according to any one of claims 1 to 4, wherein a plurality of contact portions between the braking force receiving portion and the intermediate rotating body are provided on the same rotation path.
[0042]
In this case, the fluctuation range of the contact portion of one member is restricted by the two adjacent contact portions of the other member, so that the relative rotation fluctuation range of the braking force receiving portion and the intermediate rotating body is reduced, and Responsiveness can be improved.
[0043]
(B) The internal combustion engine according to any one of (1) to (4), wherein the abutment portion on the braking force receiving portion side and the abutment portion on the intermediate rotating body side abut against each other. Valve timing control device.
[0044]
In this case, the braking force can be reliably transmitted between the braking force receiving portion and the intermediate rotating body, and the surface pressure of the contact portion is reduced, so that the durability of the component can be improved.
[0045]
(C) an assembling angle operating mechanism is provided on a radial guide provided on one of the driving rotary body and the driven rotary body, and is provided so as to be rotatable relative to the driving rotary body and the driven rotary body; An intermediate rotator having a spiral guide on the surface facing the radial guide, a movable guide portion displaceably engaged with the radial guide and the spiral guide, the driving rotator and the driven rotator 5. A structure comprising a portion of one of the other members separated from the center of rotation and a link for swingably connecting the movable guide portion. (B) The valve timing control device for an internal combustion engine according to any of (b).
[0046]
In this case, by setting the inclination of the spiral of the spiral guide to be gentle, it is possible to prevent the intermediate rotating body from rotating in response to a torque input from the driven shaft member side. Therefore, it is possible to eliminate the problem that rattling occurs between the intermediate rotating body and the braking force receiving portion due to the fluctuation torque of the camshaft.
[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 of the plate-shaped member of the embodiment.
FIG. 5 is a perspective view of the plate-like member of the embodiment as viewed from the rear side.
FIG. 6 is a front view of the plate-shaped member of the embodiment.
FIG. 7 is a sectional view of the same embodiment, taken along line BB of FIG. 6;
[Explanation of symbols]
2. Hysteresis brake (electromagnetic brake)
3: driven shaft member (driven rotator)
5. Drive ring (drive rotator)
6 ... Assembly angle operating mechanism 19 ... Intermediate rotor 22 ... Electromagnetic coil (braking force generator)
23 ... Braked rotating body (braking force receiving unit)
34 ... bearing 35 ... protruding piece (contact part)
36 ... Rubber bush (elastic body)
37 ... columnar projection (contact part)

Claims (4)

A driving rotor that is rotationally driven by a crankshaft of an internal combustion engine, a driven rotor composed of a camshaft or a separate member coupled to the same shaft, and is rotatable relative to the driving rotor and the driven rotor. An assembling angle operation mechanism for changing an assembling angle between the driving rotator and the driven rotator by rotating the intermediate rotator; and rotating the rotator to the intermediate rotator. An electromagnetic brake for applying a braking force to perform a dynamic operation, and a valve timing control device for an internal combustion engine comprising:
The braking force generating portion of the electromagnetic brake is fixed to a non-rotating member, and the braking force receiving portion of the electromagnetic brake is relatively rotatably supported by the braking force generating portion via a bearing. A valve timing control device for an internal combustion engine, characterized in that contact portions that come into contact with each other on the same rotational path are provided so as to be able to come and go, and the two contact portions come into contact with each other by rotation of an intermediate rotating body. . The valve timing control device for an internal combustion engine according to claim 1, wherein the contact portion on at least one side of the braking force receiving portion and the intermediate rotating body is formed by a plane extending in a radial direction and an axial direction. 3. The valve timing control device for an internal combustion engine according to claim 1, wherein an elastic body is provided at a contact portion of at least one of the braking force receiving portion and the intermediate rotating body. 4. The valve timing control device for an internal combustion engine according to claim 3, wherein the elastic body is provided so as to cover both front and rear surfaces of the contact portion in the rotational direction.

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