JP2008121759A - Damper of variable damping force - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a damper of a variable damping force which prevents any bite of magnetic particles in an oil seal of a cylinder, and enhances the durability of a product and reduces the cost and the weight by reducing the filling amount of a magnetic fluid. <P>SOLUTION: A piston 5 is slidably stored in a cylinder 2 filled with a liquid, and the inside of the cylinder 2 is demarcated into two liquid chambers 7, 8. A damping passage 9 through which the liquid is distributed is provided in the piston 5, and a resistance control unit 13 is provided in the middle of the damping passage 9. The resistance control unit 13 comprises: a fluid circulation passage 16 filled with the magnetic fluid; an electromagnetic coil 27 for applying the magnetic field to the magnetic fluid; a rotary fan 21 for converting the flowing energy of the liquid passing through the damping passage 9 into the rotational force; and a rotary blade 17 for allowing the magnetic fluid in the liquid circulation passage 16 to flow interlockingly with the rotary fan 21. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a damper that is used in a vehicle suspension or the like and obtains a damping force by utilizing a flow resistance of a liquid, and more particularly to a variable damping force damper that can arbitrarily adjust a generated damping force.

  In a general damper used for a vehicle suspension, a piston is slidably accommodated in a cylinder filled with liquid, and a liquid chamber defined by the piston communicates with a damping passage. And if a piston and a cylinder operate | move relatively, a liquid will distribute | circulate in the attenuation | damping channel | path and a damping force will be generated in that case.

Further, as this type of damper, there is known a damper in which a generated fluid is variably controlled by filling a cylinder with a magnetic fluid and controlling the viscosity of the magnetic fluid (for example, see Patent Document 1).
Specifically, this variable damping force damper is provided with, for example, an electromagnetic coil for controlling the viscosity of the magnetic fluid in the vicinity of the damping path of the piston, and the damping path is controlled by controlling the magnetic field generated by this electromagnetic coil. The viscosity of the magnetic fluid passing through is adjusted.
Japanese Examined Patent Publication No. 62-18775

  However, since this conventional variable damping force damper is filled with a magnetic fluid containing magnetic particles such as iron powder, the magnetic particles enter the oil seal that prevents liquid leakage between the cylinder and the piston rod. There is a concern that the oil seal is likely to be worn.

  In addition, the magnetic fluid is more expensive than a general damper liquid and has a heavy specific gravity. Therefore, in the conventional variable damping force damper, one of the problems to be solved is an increase in product cost and an increase in weight. It has become.

  Accordingly, the present invention makes it possible to prevent biting of the magnetic particles into the oil seal of the cylinder and to reduce the filling amount of the magnetic fluid, thereby improving the durability of the product, reducing the cost and reducing the weight. An object of the present invention is to provide a variable damping force damper that can perform the above operation.

The invention according to claim 1, which solves the above problem, includes a cylinder filled with a liquid (for example, a cylinder 2 in an embodiment described later) and two cylinders that are slidably accommodated in the cylinder. A piston (e.g., a piston 5 in an embodiment described later) that is separated from a liquid chamber (e.g., an expansion side liquid chamber 7 and a contraction side liquid chamber 8 in an embodiment described later) and the two liquid chambers communicate with each other. A damping passage (for example, a damping passage 9 in an embodiment described later) for imparting resistance to the liquid flowing according to the relative operation of the cylinder and the piston, and resistance control means for variably controlling the resistance imparted to the liquid in the damping passage. (For example, a resistance control unit 13 in an embodiment described later), and a variable damping force damper (for example, a variable damping force damper 1 in an embodiment described later), The control means includes a hydraulic actuator (for example, a rotary fan 21 in an embodiment described later) that operates by receiving the flow energy of the liquid passing through the attenuation passage, and a fluid filling chamber (for example, an implementation described later) filled with magnetic fluid. Fluid circulation passage 16) in the embodiment, resistance generating means (for example, a rotor blade 17 in an embodiment to be described later) driven in conjunction with the hydraulic actuator and driven in the fluid filling chamber, and magnetic fluid in the fluid filling chamber An electromagnetic coil that controls viscosity (for example, an electromagnetic coil 27 in an embodiment described later) is provided.
As a result, when the cylinder and the piston operate relative to each other and the liquid flows through the damping passage, the hydraulic actuator is activated by receiving the flow energy of the liquid, and the resistance generating means interlocking with the hydraulic actuator is provided in the fluid filling chamber. Driven. At this time, the resistance generating means receives an operating resistance by the magnetic fluid in the fluid filling chamber, and this operating resistance is controlled by the viscosity of the magnetic fluid. Therefore, by controlling the viscosity of the magnetic fluid by the electromagnetic coil, the operating resistance of the resistance generating means is adjusted, and as a result, the operating resistance of the hydraulic actuator applied to the liquid flowing through the attenuation passage is adjusted. Further, since the viscosity control by the electromagnetic coil only needs to be performed on the magnetic fluid in the fluid filling chamber, the liquid chamber in the cylinder is filled with a normal damper liquid that does not contain the magnetic fluid.

  According to a second aspect of the present invention, in the variable damping force damper according to the first aspect, the resistance generating means is constituted by a rotary blade that rotates in the fluid filling chamber.

According to a third aspect of the present invention, in the variable damping force damper according to the first or second aspect, the hydraulic actuator faces the damping passage and corresponds to the flow velocity of the liquid passing through the damping passage. It is characterized by comprising a rotating fan (for example, a rotating fan 21 in an embodiment described later) that rotates.
As a result, when the liquid flows through the attenuation passage with the relative operation of the cylinder and the piston, the rotating fan rotates according to the flow velocity of the liquid flowing through the attenuation passage, and the rotational force of the rotating fan causes the inside of the fluid filling chamber to rotate. The resistance generating means is driven.

According to a fourth aspect of the present invention, in the variable damping force damper according to the first or second aspect, the hydraulic actuator is configured by a liquid-tight hydraulic motor (for example, a hydraulic motor 42 in an embodiment described later), The hydraulic motor is interposed in series in the damping passage.
As a result, when the liquid flows through the damping passage with the relative operation of the cylinder and the piston, the hydraulic motor is operated by the hydraulic energy of the liquid flowing through the damping passage, and the rotational force of the hydraulic motor causes the hydraulic motor to move inside the fluid filling chamber. The resistance generating means is driven.

According to a fifth aspect of the present invention, in the variable damping force damper according to any one of the first to fourth aspects, a fluid circulation passage (for example, a fluid in an embodiment described later) in which a magnetic fluid flows in the fluid filling chamber. A circulation passage 16) is provided, and the electromagnetic coil is arranged close to a part of the fluid circulation passage.
As a result, when the fluid flows through the attenuation passage and the hydraulic actuator is actuated, the resistance generating means is driven in conjunction with the hydraulic actuator, and the magnetic fluid flows in the fluid circulation passage. Thus, when the magnetic fluid flows in the fluid circulation passage, the viscosity of the magnetic fluid passing through the position close to the electromagnetic coil is affected by the electromagnetic coil, and the flow resistance in the fluid circulation passage is controlled by the electromagnetic coil. Become. As a result, the operating resistance of the resistance generating means is controlled by the electromagnetic coil.

  According to the first aspect of the present invention, the flow energy of the fluid passing through the attenuation passage is converted into the drive of the resistance generating means in the fluid filling chamber via the hydraulic actuator, and the viscosity of the magnetic fluid in the fluid filling chamber is changed. Since it can be controlled by an electromagnetic coil, the liquid chamber in the cylinder can be filled with a normal damper liquid that does not contain magnetic fluid, and the magnetic particles can be reliably prevented from biting into the oil seal of the cylinder. The filling amount of the magnetic fluid can be greatly reduced. Therefore, according to the present invention, the durability of the damper can be improved by eliminating the biting of the magnetic fluid into the oil seal, and the manufacturing cost of the damper can be reduced by reducing the amount of the magnetic fluid used. Weight reduction can be achieved.

  According to the second aspect of the present invention, since the resistance generating means is constituted by the rotor blades, the manufacturing cost can be reduced by simplifying the structure of the resistance generating means.

  According to the third aspect of the present invention, since the resistance generating means is driven by the rotational force of the rotating fan that rotates in accordance with the flow velocity of the liquid flowing in the attenuation passage, the manufacturing cost is reduced by simplifying the structure. be able to.

  According to the fourth aspect of the present invention, the hydraulic pressure energy of the liquid flowing in the attenuation passage can be almost reversibly converted into the operation of the resistance generating means via the liquid-tight hydraulic motor. Even when the relative operation speed of the cylinder and the piston is low, effective damping force control by the electromagnetic coil can be performed.

  According to the fifth aspect of the present invention, the flow of the magnetic fluid is caused to flow in the fluid circulation passage by the resistance generating means interlocked with the hydraulic actuator, and the influence of the viscosity control by the electromagnetic coil is generated through the fluid circulation passage. Since it can be made to act on a means, efficient damping force control by an electromagnetic coil is realizable, without causing the enlargement of an electromagnetic coil and the increase in power consumption.

Embodiments of the present invention will be described below with reference to the drawings. First, the first embodiment shown in FIGS. 1 to 4 will be described.
FIG. 1 is a longitudinal sectional view of a variable damping force damper 1 according to the present invention. The variable damping force damper 1 is a so-called single tube type damper used for a vehicle suspension. The cylinder 2 is filled with a liquid L ₁ (a general damper liquid not including a magnetic fluid) and a piston. A piston 5 connected to the rod 4 is slidably accommodated in the cylinder 2.

The piston rod 4 is slidably supported on the end portion of the bottomed cylindrical cylinder 2 via a rod guide 6, and the piston 5 extends inside the cylinder 2 with an extension side liquid chamber 7 and a contraction side liquid chamber 8. It is divided into. The piston 5 is provided with an attenuation passage 9 that allows the expansion side liquid chamber 7 and the contraction side liquid chamber 8 in the cylinder 2 to communicate with each other. When the cylinder 2 and the piston 5 move relative to each other, the liquid L ₁ passes through the attenuation passage 9. It has come to pass. In the variable damping force damper 1, the vibration and impact applied between the cylinder 2 and the piston rod 4 are damped by the flow resistance of the liquid L ₁ passing through the damping passage 9. In the figure, 30 is an oil seal provided at the inner peripheral edge of the rod guide 6 inside the cylinder 2, and 31 is a dust seal provided at the outer peripheral edge of the cylinder 2 of the rod guide 6. .

  A free piston 10 is slidably accommodated on the bottom side of the cylinder 2, and the interior of the cylinder 2 is divided into a liquid chamber (contraction side liquid chamber 8 and expansion side liquid chamber 7) and a gas chamber 11. Yes. The free piston 10 moves in the cylinder 2 in accordance with the increase / decrease in the volume of the piston rod 4 with respect to the cylinder 2, thereby allowing the piston rod 4 to freely move back and forth.

As shown in FIGS. 2 to 4, the piston 5 includes a substantially cylindrical piston body 12 that is slidably fitted to the cylinder 2, and a liquid that is attached to the piston body 12 and flows through the damping passage 9. A resistance control unit 13 (resistance control means) that variably controls the resistance applied to L ₁ is provided, and the end of the piston rod 6 is connected to the piston body 12 via the resistance control unit 13.

  The piston body 12 has a recess 14 for attaching the resistance control unit 13 to the end face facing the contraction-side liquid chamber 8, and extends through the piston body 12 in the axial direction at the outer peripheral edge of the recess 14. The attenuation passage 9 that communicates the side liquid chamber 7 and the contraction side liquid chamber 8 is formed. The damping passage 9 is provided with an annular region coaxial with the outer peripheral surface of the piston body 12 in the vicinity of a substantially intermediate portion in the axial direction of the piston body 12.

The resistance control unit 13 includes a substantially cylindrical unit case 15 having a smaller diameter than the piston main body 12, and a fluid circulation passage 16 (fluid filling chamber) to be described later in which the magnetic fluid L ₂ is filled in the unit case 15. A rotary blade 17 (resistance generating means) that is formed and crosses the fluid circulation passage 16 is rotatably installed in the shaft core portion. One end of the rotor blade 17 is supported in the unit case 15 via the bearing 18 </ b> A, and the other end is supported by the rotating shaft 19 that penetrates the wall of the unit case 15. The plurality of blade portions 20 are rotated, thereby causing the magnetic fluid L ₂ in the fluid circulation passage 16 to flow. An oil seal (not shown) is interposed between the wall of the unit case 15 and the rotary shaft 19 that passes through the wall. 2 is an oil seal interposed between the rotary shaft 19 and the wall of the unit case 15 on the bearing 18A side.

In addition, the resistance control unit 13 includes a rotating fan 21 (hydraulic actuator) that rotates by receiving the flow energy of the liquid L ₁ that flows in the attenuation passage 9, and the rotating fan 21 is a wall at the end of the unit case 15. The shaft 19 is pivotally supported so as to be integrally rotatable. Therefore, the rotary blade 17 in the unit case 15 rotates integrally with the rotary fan 21. The rotating fan 21 has a short-axis cylindrical body 22 having substantially the same outer diameter as that of the unit case 15, and is provided on the outer peripheral surface of the body 22 so as to protrude from the damping passage 9 (near the center of the piston body 12 in the axial direction). A plurality of fins 23 facing the annular region). The plurality of fins 23 are installed on the body 22 so as to be inclined with respect to the axis of the piston body 12. Further, the end of the rotating shaft 19 protruding from the rotating fan 21 is supported by the piston body 12 via a bearing 18B.

  By the way, the rotary blade 17 is accommodated in a circular accommodating chamber 24 provided in the unit case 15, and at two positions spaced in the circumferential direction of the accommodating chamber 24, two of the fluid circulation passages 16 are formed. Supply / discharge ports 25a and 25b are provided.

  Here, the fluid circulation passage 16 will be described. As shown in FIGS. 2 to 4, the passage 16 includes an annular passage 26 a extending cylindrically in the unit case 15 along the axial direction, and the annular passage. An end passage 26b extending radially inward from the end on the piston rod 4 side of 26a and extending in the axial direction of the unit case 15 from the vicinity of the radially inner end of the end passage 26b The straight passage 26c, the one supply / discharge port 25a connected to the end of the straight passage 26c on the rotary fan 21 side, the storage chamber 24 of the rotary blade 17 facing the one supply / discharge port 25a, and the other The supply / exhaust port 25b, and the other supply / exhaust port 25b and a plurality of branch passages 26d connecting the ends of the annular passage 26a on the rotary fan 21 side are configured.

Then, on the inner wall of the annular passage 26a in the unit case 15, the electromagnetic coil 27 is provided for controlling the viscosity by applying a magnetic field to the magnetic fluid L ₂ passing through the annular passage 26a. The energization cable 28 of the electromagnetic coil 27 is drawn to the outside along the axial center portion of the piston rod 4, and the energization control of the electromagnetic coil 27 is performed by an external controller (not shown).

In the above configuration, the variable damping force damper 1 receives an input of vibration or impact, and when the piston rod 4 and the cylinder 2 are relatively operated in the axial direction, the expansion side liquid chamber 7 and the contraction side liquid chamber 8 are passed through the damping passage 9. distribution of the liquid L ₁ occurs between. When the liquid L ₁ passes through the attenuation passage 9, the liquid L ₁ hits the rotation fan 21 in the attenuation passage 9 and rotates the rotation fan 21 with a force corresponding to the flow rate of the liquid L ₁ . Thus when the rotary fan 21 rotates, rotor blades 17 of the resistance control unit 13 is rotated in conjunction, flowing the magnetic fluid L ₂ in the fluid circulation passage 16. In this case, the magnetic fluid L ₂ flowing an annular passage 26a portion of the fluid circulation passage 16 is controlled viscosity by magnetic field generated by the electromagnetic coil 27, as a result, rotor blade 17 is subjected to rotational resistance. This rotational resistance acts as a flow resistance on the liquid L ₁ passing through the attenuation passage 9 through the rotary fan 21.

The variable damping force damper 1, As described above, the flow energy of the liquid L ₁ passing through the damping passage 9, and converts the rotation of the rotary blade 17 of the resistance control unit 13 through the rotary fan 21, the since that is the viscosity of the magnetic fluid L ₂ flowing in the fluid circulation passage 16 by the operation of the rotary blade 17 so as to control the electromagnetic coil 27, the liquid to be filled into the liquid chamber 7, 8 of the larger cylinder 2 volumes while using conventional damper fluid not containing magnetic particles as L _1, it is possible to arbitrarily control the generated damping force by the electromagnetic coil 27.

Therefore, in the case of using the variable damping force damper 1 includes a cylinder 2 and the oil seal 30 for sealing between the piston rod 4 there is no fear that the magnetic particles of the magnetic fluid L ₂ from biting, durability of the oil seal 30 sex and it is possible to reliably improve, moreover, since the cost can be greatly reduced usage of heavy magnetic fluid L ₂ of high specific gravity, it is possible to also reduce the weight of the product cost.

In the variable damping force damper 1, the rotary fan 21 having a simple structure is used as a hydraulic actuator that converts the flow energy of the liquid L ₁ passing through the damping passage 9 into the rotation of the rotor blades. The manufacturing cost can be further reduced. In particular, in this embodiment, since the fins 23 of the rotary fan 21 are inclined with respect to the axial direction, even if the rotary fan 21 stops, the liquid in the attenuation passage 9 is circulated. Can be compensated.

In the variable damping force damper 1 of this embodiment, the magnetic fluid L ₂ in the fluid circulation passage 16 to flow by the rotary blade 17 rotates integrally with the rotary fan 21, the magnetic fluid L ₂ is in the fluid circulation passage 16 when passing through the vicinity of the electromagnetic coil 27, since the magnetic fluid L ₂ changes the magnetic field influence greatly received by viscous resistance of the electromagnetic coil 27, without increasing the size and power consumption of the electromagnetic coil 27, Efficient damping force control by the electromagnetic coil 27 can be performed.

  Next, a second embodiment of the present invention shown in FIGS. 5 and 6 will be described. The variable damping force damper 101 of this embodiment is different from that of the first embodiment only in the configuration of the piston 105, and other parts are the same as those of the first embodiment. Therefore, only the piston 105 will be described below, and description of the other parts will be omitted. In addition, about a common part with 1st Embodiment, FIGS. 1-4 shall be referred suitably.

The piston 105 of the variable damping force damper 101 is assembled with a unit case 15 similar to the resistance control unit of the first embodiment on one end side of the piston body 112 in the axial direction, and the other end of the piston body 112 in the axial direction. A circular pump housing hole 40 is formed on the side, and the end surface on the pump housing hole 40 side is sealed with a disk-shaped piston cover 41. Internal structure of the unit case 15 is the same as the first embodiment, as to cause the flow in the magnetic fluid L ₂ in the fluid circulation passage 16 (see FIG. 2) by the rotation of the rotary blade 17 (see FIG. 2) It has become.

  The rotary shaft 17 that pivotally supports the rotary blade 17 (see FIG. 2) passes through the axial center of the unit case 15 and the piston main body 112 and protrudes into the pump housing hole 40. On the other hand, the pump accommodation hole 40 is provided eccentrically with respect to the axis of the piston main body 112, and a vane rotor 43 constituting the vane type hydraulic motor 42 is accommodated in the pump accommodation hole 40. A plurality of vane slots 44 are provided radially on the outer periphery of the vane rotor 43, and vanes 46 spring-biased radially outward by springs 45 are accommodated in the vane slots 44 so as to freely advance and retract. The tip of each vane 46 is slidably in contact with the inner peripheral surface of the circular pump housing hole 40, and two supply / discharge ports 47 a and 47 b are provided at two spaced positions on the outer peripheral wall of the pump housing hole 40. It has been.

  The piston cover 41 is formed with a first communication hole 48 that communicates one supply / discharge port 47a of the hydraulic motor 42 and the extension side working chamber 7 (see FIG. 1). A second communication hole 49 is formed to communicate the supply / discharge port 47b and the contraction side working chamber 8 (see FIG. 1). The first and second communication holes 48 and 49, together with the two supply / discharge ports 47 a and 47 b and the pump accommodation hole 40, form an attenuation passage 109 that allows the liquid to flow between the liquid chambers 7 and 8 (see FIG. 1). It is composed. That is, in this embodiment, a sealed hydraulic motor 42 is interposed in series in the middle of the attenuation passage 109.

  In the variable damping force damper 101, since the piston 105 is configured as described above, when the piston 105 and the cylinder are relatively operated by the input of vibration or shock, one of the first and second communication holes 48 and 49 is selected. The liquid that has flowed in from the rotation rotates the hydraulic motor 42, and the entire amount that has flowed in is discharged to the other side. Specifically, the liquid flowing into one communication hole 48 or 49 rotates the vane rotor 43 in one direction while expanding the volume of the working chamber between the adjacent vanes 46 and 46, and the other rotation of the vane rotor 43 causes the other. Are discharged into the communication hole 49 or 48.

Thus the hydraulic motor 42 is rotated, the flow of magnetic fluid L ₂ in the rotary blade 17 in the unit case 15 in the same manner fluid circulation passage 16 (see FIG. 2) is rotated (see FIG. 2) in the first embodiment As a result, the hydraulic motor 42 receives rotational resistance corresponding to the magnetic field control by the electromagnetic coil 27 (see FIG. 2). The rotational resistance of the hydraulic motor 42 becomes the operating resistance of the liquid in the damping passage 109, and the generated damping force by the variable damping force damper 101 is arbitrarily controlled according to the control of the electromagnetic coil 27 (see FIG. 2). It will be.

  The variable damping force damper 101 of this embodiment can obtain substantially the same effect as that of the first embodiment, and almost all of the liquid flowing through the damping passage 109 of the piston 105 contributes to the operation of the hydraulic motor 42. Therefore, even when the relative operation speed between the piston 105 and the cylinder is low, the hydraulic motor 42 operates and the control of the electromagnetic coil 27 can be reliably reflected in the generated damping force.

  In addition, this invention is not limited to said embodiment, A various design change is possible in the range which does not deviate from the summary. For example, the above-described embodiment is a so-called single tube type variable damping force damper, but it can also be applied to a so-called twin tube type variable damping force damper in which cylinders forming a liquid chamber are doubled. It is. In this case, the attenuation passage and the resistance control unit may be provided in the base valve.

1 is a longitudinal sectional view of a variable damping force damper according to a first embodiment of the present invention. The fragmentary sectional perspective view of the piston of the embodiment. Sectional drawing corresponding to the AA cross section of FIG. 2 of the embodiment. Sectional drawing corresponding to the BB cross section of FIG. 2 of the embodiment. The partial cross section perspective view of the piston of 2nd Embodiment of this invention. The top view which removed the cover of the piston of the embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,101 ... Variable damping force damper 2 ... Cylinder 5,105 ... Piston 7 ... Elongation side liquid chamber (liquid chamber)
8 ... Contraction side liquid chamber (liquid chamber)
9, 109 ... damping path 13 ... resistance control unit (resistance control means)
16 ... Fluid circulation passage (fluid filling chamber)
17 ... Rotating blade (resistance generating means)
21 ... Rotary fan (hydraulic actuator)
27 ... electromagnetic coil 42 ... hydraulic motor L 1 _... liquid L 2 _... ferrofluid

Claims (5)

A cylinder filled with liquid,
A piston that is slidably accommodated in the cylinder and separates the inside of the cylinder into two liquid chambers;
A damping passage communicating between the two liquid chambers and imparting resistance to the liquid flowing in accordance with the relative operation of the cylinder and the piston;
Resistance control means for variably controlling the resistance applied to the liquid in the attenuation passage;
In a variable damping force damper having
The resistance control means;
A hydraulic actuator that operates in response to the flow energy of the liquid passing through the damping passage;
A fluid filling chamber filled with magnetic fluid;
A resistance generating means that operates in conjunction with the hydraulic actuator and is driven in the fluid filling chamber;
An electromagnetic coil for controlling the viscosity of the magnetic fluid in the fluid filling chamber;
A variable damping force damper characterized by having a configuration including   The variable damping force damper according to claim 1, wherein the resistance generating means is constituted by a rotary blade that rotates in the fluid filling chamber.   3. The variable damping force damper according to claim 1, wherein the hydraulic actuator is configured by a rotary fan that faces the damping passage and rotates in accordance with a flow velocity of the liquid passing through the damping passage. .   3. The variable damping force damper according to claim 1, wherein the hydraulic actuator is configured by a liquid-tight hydraulic motor, and the hydraulic motor is interposed in series in the damping passage. Providing a fluid circulation passage through which the magnetic fluid flows in the fluid filling chamber;
The variable damping force damper according to claim 1, wherein the electromagnetic coil is disposed close to a part of the fluid circulation passage.

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