JP2006283798A - Swing type damping device and belt tensioner device having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase sealability in a sliding clearance between a casing 10 and a swing piston 51 without increasing its dimensional accuracy in a swing type damping device in which a swing piston 51 is disposed in the casing 10 and its internal space 10a is divided into two fluid chambers C1 and C2, these both fluid chambers C1 and C2 are allowed to communicate with each other through a communication passage 55, a magnetic viscous fluid F is filled in these fluid chambers C1 and C2 and the communication passage 55, and a magnetic field is applied to the magnetic viscous fluid F in the communication passage 55 to damp the relative rotation of the swing piston 51 to the casing 10. <P>SOLUTION: This swing type damping device comprises a second magnetic field applying means 60 applying a magnetic field to the magnetic viscous fluid F in the sliding clearance between the casing 10 and the swing piston 51. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a oscillating damping device that changes a damping force with respect to relative rotation between a casing and a oscillating piston using a magnetorheological fluid whose shear stress changes according to an applied magnetic field, In particular, the present invention relates to a measure for improving the sealing performance in the sliding gap between the casing and the swing piston.

  Generally, as a conventional oscillating type damping device using a magnetorheological fluid, one described in Patent Document 1 is known.

  In this case, an oscillating piston composed of a cylindrical element and piston blades is arranged in an inner space of a cylindrical casing to divide the inner space into two fluid chambers, while a cross-sectional circle around the cylindrical element. By disposing the arc-shaped sleeve and the insulating layer integrally with the casing, a communication path composed of a gap having an arc-shaped cross section that communicates between the fluid chambers is formed between the sleeve and the casing. The fluid chamber and the communication path are filled with a magnetorheological fluid.

Then, by applying a magnetic field to the magnetorheological fluid in the communication path, the shear viscosity of the magnetorheological fluid in the communication path is increased to increase the apparent viscosity. Therefore, the relative rotation of the oscillating piston with respect to the casing can be efficiently attenuated with a magnetic force that is small enough to apply a magnetic field only to the communication path.
JP-T-2002-524703 (pages 6-7, FIG. 4)

  By the way, in the above-described oscillating type damping device, since the magnetorheological fluid passes through the sliding gap between the casing and the oscillating piston, the damping force decreases accordingly, and the appropriate magnetic force is reduced. There is a drawback that the viscosity characteristic cannot be obtained.

  For this, it is conceivable to increase the dimensional accuracy of the sliding gap so that the magnetorheological fluid does not pass through the sliding gap. However, in that case, there is a problem that the processing cost of the parts increases. become.

  The present invention has been made in view of such various points, and its main object is to arrange an oscillating piston in a casing to divide the internal space into two fluid chambers, and to connect the two fluid chambers to each other. Oscillations that make the fluid chambers and communication passages filled with a magnetorheological fluid and apply a magnetic field to the magnetorheological fluid in the communication passages to attenuate the relative rotation of the oscillation piston with respect to the casing. In the type damping device, by utilizing the characteristics of the magnetorheological fluid, the sealing performance of the sliding gap between the casing and the swing piston can be improved without increasing the dimensional accuracy. is there.

  In order to achieve the above object, the present invention focuses on the magnetorheological fluid interposed in the sliding gap between the casing and the oscillating piston, and increases the viscosity by applying a magnetic field to the magnetorheological fluid. The sealing performance of the sliding gap was increased.

  Specifically, the present invention includes a casing having an internal space having a generally sectoral cross section formed so as to extend radially outward from the axial center side and expand in the circumferential direction, and the internal space of the casing includes the casing. An oscillating piston that is slidable with respect to the casing while being slidable relative to each other in two rotational directions around the axis and that divides the internal space into two fluid chambers divided in the circumferential direction; One or more communication passages that communicate the two fluid chambers with each other, and a magnetic viscosity that fills the two fluid chambers and one or more communication passages and changes the shear stress in accordance with the applied magnetic field And a magnetic field applying means for applying a magnetic field to the magnetorheological fluid in the one or more communication paths, and applying a magnetic field to the magnetorheological fluid in the at least one communication path by the magnetic field application means. Magnetorheological fluid It assumes oscillating damping apparatus that attenuate the relative rotation of the swing piston relative to the casing by varying the shear stress.

  Then, after the magnetic field applying means is the first magnetic field applying means, a second magnetic field applying means for applying a magnetic field to the magnetorheological fluid in the sliding gap between the casing and the swing piston is provided. Be prepared.

  In the above configuration, the one or more communication passages may be formed by a part of the entire region of the sliding gap, and for the second magnetic field application unit, In addition to the magnetorheological fluid in the sliding gap, it may be configured to apply a magnetic field to the magnetorheological fluid in the two fluid chambers. In these cases, the first magnetic field applying means and the second magnetic field applying means can be constituted by a single magnetic field applying means. It is also possible to provide an electromagnet having a coil portion wound around the outer periphery of the casing and a power supply means for energizing the electromagnet, and the magnetic field applying means can be constituted by the electromagnet and the power supply means.

  Furthermore, it has a fixed part fixed to the fixed side and a pressing part for pressing the belt, and swings between a direction in which the pressing part presses the belt and a direction opposite to the pressing direction. An oscillating portion supported by the fixing portion, an urging means for urging the oscillating portion toward the belt pressing direction with respect to the fixing portion, and an attenuating means for attenuating the rotation of the oscillating portion As the attenuating means in the belt tensioner device provided with the above-mentioned, the oscillating type attenuating device can be used. In this case, the casing of the swing type damping device is connected to one of the fixed portion and the swing portion, and the swing piston of the swing type damping device is connected to the fixed portion and the swing portion. It will be connected to the other of the parts.

  According to the present invention, the oscillating piston is disposed in the internal space of the casing to divide the internal space into two fluid chambers, while forming a communication passage that communicates between the two fluid chambers. The communication path is filled with a magnetorheological fluid, and the magnetic circuit applies a magnetic field to the magnetorheological fluid in the communication path to change the shear stress, thereby reducing the relative rotation of the swing piston with respect to the casing. In the dynamic damping device, at least a part of a gap region generated between the swing piston and the casing is used as the communication path, and the magnetic circuit is further interposed between the swing piston and the swing piston. Compared to the conventional case in which a new clearance is provided in addition to the clearance around the oscillating piston, and the communication path is configured by the clearance, the number of parts and the assembly of the parts are increased. It is possible to contribute to a reduction in manufacturing cost by reducing the degree, it is possible to improve the reliability and durability by reducing the sealing area around the swing piston.

  2 and 3 show the overall configuration of the belt tensioner device according to the embodiment of the present invention. In this belt tensioner device, a part of the output torque of the automobile engine is transmitted through one transmission belt. It is used for applying a predetermined tension to the transmission belt in a belt transmission device having a serpentine layout that is transmitted to the auxiliary machine.

  The belt tensioner device is disposed so as to overlap with the fixed portion 10 fixed to the engine side and the fixed portion 10, and the belt tensioner device swings on the fixed portion 10 in two rotation directions around a predetermined swing axis P. And an oscillating portion 20 supported movably. The swinging part 20 has a tension pulley 30 as a pressing part that presses the transmission belt, and the tension pulley 30 presses the transmission belt between the fixed part 10 and the swinging part 20 ( A torsion coil spring 40 that constantly urges the oscillating portion 20 to rotate (counterclockwise in FIG. 2) and an oscillating damper 50 that attenuates the rotation of the oscillating portion 20 are interposed. .

  An annular peripheral wall 11 protruding toward the swinging part 20 is provided at the periphery of the fixed part 10, and a part of the peripheral wall 11 in the circumferential direction penetrates the peripheral wall 11 in the radial direction and A fixed-side locking portion 12 having a shape opened to the swinging portion 20 side is provided. On the inner peripheral side of the peripheral wall 11, a cylindrical portion 13 having a circular cross section and having the pivot axis P as an axis forms a peripheral groove having a concave cross section with the peripheral wall 11. It is erected. The cylindrical portion 13 includes an axial hole 14 that penetrates the axial center portion of the cylindrical portion 13 in the axial direction, and a substantially fan-shaped internal section that extends radially outward from the axial hole 14 and expands in the circumferential direction. A space 10a is formed.

  On the other hand, a shaft member 21 arranged so as to extend along the swing axis P is provided at the shaft center portion of the swing portion 20 so as to swing toward the fixed portion 10 so as to protrude integrally. Yes. The shaft member 21 is fitted and held in the shaft hole 14 of the fixed portion 10 so as to be rotatable about the swing axis P, so that the swing portion 20 can swing about the swing axis P. Is supported by the fixing portion 10. An annular peripheral wall 22 that protrudes toward the fixed portion 10 is provided at the periphery of the swinging portion 20. A part of the circumferential wall 22 in the circumferential direction is provided with a rocking side locking portion 23 having a shape that penetrates the circumferential wall 22 in the radial direction and is opened to the fixed portion 10 side. Further, the swinging portion 20 has an arm 24 provided so as to protrude outward in the radial direction. A pivot portion 25 is provided at the tip of the arm 24, and the tension pulley 30 is supported by the pivot portion 25 so as to be rotatable about an axis Q parallel to the swing axis P.

  The torsion coil spring 40 has a cylindrical coil portion 41 and two tangs 42 and 43 on the fixed side and the swing side that protrude outwardly in the radial direction from both coil ends, although not shown. . One of the coil ends is housed in a circumferential groove between the peripheral wall 11 and the cylindrical portion 13 in the fixed portion 10, and the fixed-side tongue 42 extending from the coil end is fixed by the fixed-side locking portion 12. It is locked so as not to move in the circumferential direction. The other of the coil ends is disposed along the peripheral wall 22 on the inner peripheral side of the peripheral wall 22 of the swing part 20, and the swing side tongue 43 extending from the coil end has a swing side locking part. 23 is locked so as not to move in the circumferential direction. The torsion coil spring 40 is wound between the fixed portion 10 and the oscillating portion 20 in a state of being wound in the direction of the left-hand screw and having a reduced diameter. On the other hand, it is always urged toward the belt pressing direction (counterclockwise direction in FIG. 2).

  The oscillating damper 50 is disposed in the internal space 10a of the fixed portion 10 as a casing, and divides the internal space 10a into first and second fluid chambers C1 and C2 divided in the circumferential direction. Has a swinging piston 51. The swinging piston 51 is provided integrally with the shaft portion 52 that is a portion of the shaft member 21 located in the internal space 10a and swings integrally with the shaft portion 52, and is radially outward from the shaft portion 52. It consists of the substantially rectangular partition part 53 formed so that it may extend toward the direction. Here, it is assumed that the first fluid chamber C1 is positioned on the belt pressing direction side and the second fluid chamber C2 is positioned on the anti-belt pressing direction side.

  The inner wall surface around the oscillation axis P in the internal space 10a is centered on the oscillation axis P and has a radius such that a clearance having an arcuate cross section is formed between the inner wall 10a and the outer peripheral surface of the axis portion 52. Is formed in a circular arc shape that is slightly larger than the radius of the axial center portion 52. The gap having an arcuate cross section serves as a communication passage 55 that allows the two fluid chambers C1 and C2 to communicate with each other. The clearance between the partition 53 of the swing piston 51 and the inner wall surface of the internal space 10 a is a sliding clearance that allows the partition 53 to slide with the rotation of the swing piston 51 relative to the fixed portion 10. Has been.

  The two fluid chambers C1 and C2 and the communication path 55 are filled with a magnetorheological fluid F that changes viscosity (shear stress) in accordance with an applied magnetic field. The magnetorheological fluid F has a smaller volume in the first fluid chamber C1 and a larger volume in the second fluid chamber C2 when the swinging portion 20 rotates in the belt pressing direction (counterclockwise direction in FIG. 2). Therefore, when moving from the first fluid chamber C1 to the second fluid chamber C2 via the communication passage 55, while the swinging portion 20 rotates in the anti-belt pressing direction (clockwise direction in the figure), Since the volume of the second fluid chamber C2 decreases and the volume of the first fluid chamber C1 increases, the second fluid chamber C2 moves from the second fluid chamber C2 to the first fluid chamber C1 via the communication path 55.

  Here, the “magnetorheological fluid” is obtained by dispersing and containing magnetic particles having a particle size of 0.5 to 100 μm in a solvent such as hydrocarbon or silicone. The properties are different from those of “magnetic fluid”, which is obtained by dispersing and incorporating magnetic particles having a relatively small particle size of 1 to 100 nm in a solvent, and the fields of application are also different.

  In the present embodiment, the oscillating damper 50 includes the magnetorheological fluid F in the communication path 55, the magnetorheological fluid F in each of the fluid chambers C1 and C2, and the fixed portion as schematically shown in FIG. 10 and an electromagnet 60 that applies a magnetic field to all of the magnetorheological fluid F in the sliding gap between the partition portion 53 of the swing piston 51. In addition, the virtual line of the figure has shown the magnetic force line by the electromagnet 60 typically.

  The electromagnet 60 has an electromagnetic coil 61 in which a conductive wire is wound around the outer periphery of the cylindrical portion 13 in the fixed portion 10, and the two lead wires drawn from the electromagnetic coil 61 are connected to the power supply portion 62. Has been. In the present embodiment, the electromagnet 60 constitutes the first magnetic field applying means and the second magnetic field applying means in the present invention.

  Next, the operation of the swinging damper 50 in the belt tensioner device configured as described above will be described.

  In the communication path 55 of the oscillating damper 50, since the magnetic viscosity fluid F in the communication path 55 is applied with a magnetic field and the apparent viscosity is increased, the oscillating piston 51 is relatively rotated. The passage resistance with respect to the magnetorheological fluid F trying to pass through the communication path 55 is large. Therefore, the relative rotation of the oscillating piston 51 is attenuated by the passage resistance in the communication path 55 with respect to the magnetorheological fluid F.

  At this time, in the sliding gap between the fixed portion 10 and the oscillating piston 51, the magnetic viscosity of the fluid chamber C <b> 1 (or C <b> 2) on the front side in the rotational direction of the oscillating piston 51 as the oscillating piston 51 rotates. The fluid F tries to move to the fluid chamber C2 (or C1) on the rear side in the rotation direction via the sliding gap.

  On the other hand, the magnetic field of the electromagnet 60 is applied not only to the magnetorheological fluid F in the communication path 55 but also to the magnetorheological fluid F in the sliding gap. The passage resistance to F increases. Thereby, since the sealing performance in the sliding gap is increased, the passage of the magnetorheological fluid F between the two fluid chambers C1 and C2 performed via the sliding gap is restricted. A situation in which the damping force due to the magnetorheological property of the magnetorheological fluid F is impaired due to the insufficient sealing performance of the sliding gap is suppressed.

  Therefore, according to the present embodiment, the oscillating portion 20 is urged to rotate by the torsion coil spring 40 in the direction in which the tension pulley 30 presses the transmission belt with respect to the fixed portion 10, and is oscillated by the oscillating damper 50. In the belt tensioner device in which the rotation of the portion 20 is damped, the swinging piston 51 connected integrally with the swinging portion 20 is disposed in the internal space 10a of the fixed portion 10 as the swinging damper 50. Then, the internal space 10a is divided into two fluid chambers C1 and C2 divided in the swinging direction, and the fluid chambers C1 and C2 are formed with communication passages 55 communicating with each other. C1, C2 and the communication path 55 are filled with the magnetorheological fluid F, and a magnetic field is applied to the magnetorheological fluid F in the communication path 55 to change the shear stress to rotate the swing piston 51 with respect to the fixed portion 10. When it is made to decay, the electromagnet 60 formed by winding the electromagnetic coil 61 on the cylindrical portion 13 of the fixed portion 10 is energized to generate the magnetorheological fluid F in the sliding gap between the fixed portion 10 and the swinging piston 51. Since the magnetic field is also applied, the movement of the magnetorheological fluid F between the fluid chambers C1 and C2 performed via such a sliding gap can be regulated. A decrease in damping force due to such movement of the magnetorheological fluid F can be suppressed without incurring a processing cost for increasing the dimensional accuracy.

  Moreover, since the means for applying a magnetic field to the magnetorheological fluid F in the communication passage 55 and the means for applying a magnetic field to the magnetorheological fluid F in the sliding gap are made common, each means is provided individually. Compared with the case where it does, it can suppress the increase in a number of parts and a man-hour.

  In the above-described embodiment, the communication path 55 is configured by using a part of the gap area around the axial center portion 52 of the swing piston 51. In the case where the center portion 52 is not provided, the communication passage 55 may be configured using a gap region around the portion close to the swing axis P. In addition, the communication path 55 may be configured by at least a part of an arbitrary gap region among all the gaps around the swing piston 51 regardless of the presence or absence of the axial center portion 52.

  Further, in the above embodiment, means for applying a magnetic field to the magnetorheological fluid F in the communication passage 55 and means for applying a magnetic field to the magnetorheological fluid F in the sliding gap between the fixed portion 10 and the swinging piston 51. However, each means may be provided individually.

  In the above embodiment, the electromagnet 60 is used as the magnetic force generating means. However, for example, when a constant magnetic field is always applied, a permanent magnet may be used as the magnetic force generating means.

  In the above embodiment, the fixed portion 10 of the belt tensioner device is a casing, and the swinging piston 51 disposed in the casing is connected to the swinging portion 20 integrally with the swinging portion. While the casing is set on the 20 side, the swing piston 51 may be coupled to the fixed portion 10.

  Further, in the above embodiment, the case of the belt tensioner device in which the swing type damping device according to the present invention is incorporated is described. However, the present invention is a swing type damping device in various other devices. Of course, it can be used.

It is a perspective view showing typically the whole composition of the oscillation type damper in the belt tensioner device concerning the embodiment of the present invention. It is a cross-sectional view which shows the whole structure of a belt tensioner apparatus. It is a longitudinal cross-sectional view which shows the whole structure of a belt tensioner apparatus.

Explanation of symbols

10 Fixed part (casing)
10a Internal space 20 Oscillating part 30 Tension pulley (pressing part)
40 Torsion coil spring (biasing means)
50 Oscillating damper (Oscillating damping device)
51 oscillating piston 55 communication path 60 electromagnet (first magnetic field applying means, second magnetic field applying means)
C1 First fluid chamber (fluid chamber)
C2 Second fluid chamber (fluid chamber)
F Magnetorheological fluid

Claims (6)

A casing having an internal space having a substantially sectoral cross section formed so as to extend radially outward from the axial side and expand in the circumferential direction;
The inner space of the casing is slidable with respect to the casing and is disposed so as to be relatively swingable in two rotation directions around the axis, and the inner space is divided into two fluid chambers divided in the circumferential direction. An oscillating piston;
One or more communication passages communicating the two fluid chambers with each other;
A magnetorheological fluid that fills the two fluid chambers and the one or more communication paths and changes a shear stress in response to an applied magnetic field;
Magnetic field applying means for applying a magnetic field to the magnetorheological fluid in the one or more communication paths,
By applying a magnetic field to the magnetorheological fluid in the at least one communication path by the magnetic field applying means to change the shear stress of the magnetorheological fluid, the relative rotation of the swing piston with respect to the casing is attenuated. An oscillating damping device,
The magnetic field applying means is a first magnetic field applying means,
An oscillating type damping device comprising a second magnetic field applying means for applying a magnetic field to a magnetorheological fluid in a sliding gap between the casing and the oscillating piston. The oscillating damping device according to claim 1,
The one or more communication paths are formed by a part of the whole area of the sliding gap. The oscillating damping device according to claim 1,
The oscillating type damping device, wherein the second magnetic field applying means is configured to apply a magnetic field to the magnetorheological fluid in the two fluid chambers in addition to the magnetorheological fluid in the sliding gap. The oscillating damping device according to claim 1,
The first magnetic field applying means and the second magnetic field applying means are constituted by a single magnetic field applying means. The oscillating damping device according to claim 4,
An electromagnet having a coil portion wound around the outer periphery of the casing;
Power supply means for energizing the electromagnet,
The magnetic field applying means is constituted by the electromagnet and the power feeding means. A fixed part fixed to the fixed side;
A swing part supported by the fixed part so as to be swingable between a direction in which the pressing part presses the belt and a direction opposite to the pressing direction;
A belt tensioner device comprising: an urging unit that urges the oscillating unit toward the belt pressing direction with respect to the fixing unit; and an attenuating unit that attenuates the rotation of the oscillating unit.
The damping means is constituted by the swing type damping device according to any one of claims 1, 2, 3, 4, and 5,
The casing of the swing type damping device is connected to one of the fixed part and the swing part,
The belt tensioner device, wherein the swing piston of the swing type damping device is connected to the other of the fixed portion and the swing portion.

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