JP2013087881A - Braking device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a braking device which can suppress the quantity of magnetic viscous fluid for use in the braking device to an irreducibly minimum and can provide more stabilized braking force.SOLUTION: The braking device includes: a hollow housing 10; a rotor 30 which is rotatable within the housing 10; a void 90 which is formed between an inner circumferential surface of the housing 10 and an outer circumferential surface of the rotor 30 opposed thereto, and of which the confronted two openings are each closed with a surface crossing the inner circumferential surface of the housing 10; a magnetic viscous fluid 40 to be filled within the void 90; a seal member 50 which prevents the magnetic viscous fluid 40 from leaking from the void 90; and a coil 60 which is disposed within the housing 10 and generates a magnetic field to be applied to the magnetic viscous fluid 40.

Description

  The present invention relates to a braking device using a magnetorheological fluid.

  Conventionally, a non-movable body, a movable body that can rotate outside or inside the non-movable body, a magnetic viscous fluid that is filled between the movable body and the non-movable body, and a magnetic viscous fluid that is applied A braking device having a coil for generating a magnetic field is known.

  This type of braking device uses a magnetic field applied to a magnetorheological fluid to increase the viscosity of the magnetorheological fluid, thereby reducing the rotational speed of the movable body or stopping its rotation. It is. The magnetic field applied to the magnetorheological fluid is generated by passing a current through the coil.

  For example, US Pat. No. 6,186,290 discloses two devices. The first device includes a magnetic pole piece (45) that is a non-movable body, a peripheral wall (26) that is a movable body that is rotatable outside the magnetic pole piece (45), a peripheral wall (26), and a magnetic pole piece (45). A magnetic gap (46) formed between the magnetic viscous fluid (48), and a coil (60) for generating a magnetic field applied to the magnetic viscous fluid (48). Yes. The second device includes a shaft (124) that is a non-movable body, a roller (120) that is a movable body that is rotatable outside the shaft (124), and an outer peripheral surface of the shaft (124) and a roller (120 that faces it). ) Formed between the inner peripheral surface of), a magnetorheological fluid (148) filled in the cavity (146), and a coil for generating a magnetic field applied to the magnetorheological fluid (148) ( 160).

  However, since both devices have a structure in which the magnetorheological fluid is filled up to a space communicating with the gap (46, 146) (that is, a region where shear stress of the magnetorheological fluid does not occur), a large amount of magnetorheological fluid is used. Has been. Since the magnetorheological fluid is expensive, there is a problem that such a structure is expensive to manufacture.

  Japanese Patent Application Laid-Open No. 2008-202744 discloses a case (1) that is a non-movable body, a plate (3) that is a movable body that can rotate inside the case (1), a plate (3), and a case side plate ( 11), a device including a gap formed between the magnetic viscous fluid and the coil (4) for generating a magnetic field applied to the magnetic viscous fluid is disclosed.

  However, this device also has a drawback that a large amount of magnetorheological fluid is required because the magnetorheological fluid is filled up to a space communicating with the gap (that is, a region where shear stress of the magnetorheological fluid does not occur). is there.

  A magnetorheological fluid is a suspension in which ferromagnetic particles are dispersed in a fluid such as synthetic oil, and is a low-viscosity liquid in the absence of a magnetic field. Magnetorheological fluid fills not only the voids to be generated (that is, the region where the shear stress of the magnetorheological fluid is generated) but also the space where the braking force is not substantially generated (that is, the region where the shearing stress of the magnetorheological fluid is not generated) With such a structure, the ferromagnetic particles in the fluid are likely to precipitate, resulting in a problem that the braking force is reduced and the braking characteristics are not stable.

US Pat. No. 6,186,290 JP 2008-202744 A

  The problem to be solved by the present invention is to provide a braking device capable of minimizing the amount of use of a magnetorheological fluid and obtaining a more stable braking force.

In order to solve the above problems, the present invention provides the following braking device.
1. A gap formed between a hollow housing, a rotor rotatable inside the housing, and an inner peripheral surface of the housing and an outer peripheral surface of the rotor facing the housing, and two openings facing each other A gap that is closed by a surface that intersects the inner peripheral surface of the housing, a magnetic viscous fluid that fills the gap, a seal member that prevents leakage of the magnetic viscous fluid from the gap, and the housing And a coil for generating a magnetic field applied to the magnetorheological fluid.
2. 2. The braking device according to 1, wherein the housing and the rotor are formed of high-density iron-based sintered metal.
3. 2. The braking device according to 1, wherein the housing and the rotor are formed of a high-density sintered metal containing pure iron as a main component.
4). The housing has a support portion for supporting the rotor, the density of the support portion is set lower than the density of the portion other than the support portion of the housing, and the support portion is impregnated with lubricating oil The braking device according to 2 or 3.
5. 5. The braking device according to 4, wherein the density of the support portion is less than 7 g / cm ³ and the density of the portion other than the support portion of the housing is 7 g / cm ³ or more.
6). The housing has a support part for supporting the rotor, the rotor has a supported part in contact with the support part, and the density of the supported part is higher than the density of a part other than the supported part of the rotor. 4. The braking device according to 2 or 3, wherein the braking device is set low and the supported portion is impregnated with lubricating oil.
7). 7. The braking device according to 6, wherein the density of the supported portion is less than 7 g / cm ³ and the density of the portion other than the supported portion of the rotor is 7 g / cm ³ or more.

  According to the braking device of the present invention, the magnetorheological fluid is a gap formed between the inner peripheral surface of the housing and the outer peripheral surface of the rotor facing the housing, and two openings facing each other are provided in the housing. A seal member is provided that fills a gap that is closed by a surface that intersects the inner peripheral surface, and prevents leakage of the magnetorheological fluid from the gap. Accordingly, since the magnetorheological fluid is filled only in the gap where the braking force is substantially generated (that is, the region where the shearing stress of the magnetorheological fluid is generated), the amount of use of the magnetorheological fluid is minimized. It becomes possible to suppress to. In addition, the space in which the braking force is not substantially generated (that is, the region where the shear stress of the magnetorheological fluid is not generated) is not filled with the magnetorheological fluid. As a result, the braking characteristic can be further stabilized.

FIG. 1 is a perspective view showing a braking device according to first and second embodiments of the present invention. FIG. 2 is a cross-sectional view illustrating the internal structure of the braking apparatus according to the first embodiment of the present invention. FIG. 3 is a partially enlarged view of the internal structure of the braking system related to Embodiment 1 of the present invention. FIG. 4 is a cross-sectional view showing the internal structure of the braking system related to Example 2 of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the technical scope of the present invention is not limited to the contents of the following description.

  1 is a perspective view showing a braking device according to a first embodiment of the present invention, FIG. 2 is a sectional view showing an internal structure of the braking device according to the first embodiment of the present invention, and FIG. 3 is an embodiment of the present invention. 1 is a partially enlarged view of an internal structure of a braking device according to FIG.

  The braking device according to the present embodiment includes a housing 10, a plug 20, a rotor 30, a magnetorheological fluid 40, a seal member 50, and a coil 60 (see FIGS. 1 to 3).

  The housing 10 is hollow and has a cylindrical first peripheral wall portion 11, a cylindrical second peripheral wall portion 12 having an inner diameter larger than the inner diameter of the first peripheral wall portion 11, and a bottom that covers the end portions of the first peripheral wall portion 11. A wall portion 14 is provided (see FIGS. 1 and 2). The 1st surrounding wall part 11 has the hole part 17 which penetrates the flange part 16 and the 1st surrounding wall part 11 which protrude from the outer peripheral surface of the 1st surrounding wall part 11 (refer FIG. 1). The flange portion 16 is used for fixing the housing 10. The hole 17 is a hole for drawing the lead wire 80 into the housing 10. Between the 1st surrounding wall part 11 and the 2nd surrounding wall part 12, the seat part 13 orthogonal to the 1st surrounding wall part 11 is interposing (refer FIG. 2). In the center of the bottom wall portion 14, a shaft-like support portion 15 protruding from the inner surface of the bottom wall portion 14 is provided (see FIG. 2). The support portion 15 is provided to support the rotor 30.

  The plug 20 is a disc, and is attached to the housing 10 by caulking the end portion 12a of the second peripheral wall portion 12 after the inner surface of the plug 20 is disposed so as to contact the inner surface of the seat portion 13. (See FIG. 2). A hole 21 that penetrates the plug 20 is formed in the center of the plug 20, and the shaft portion 31 of the rotor 30 is inserted into the hole 21 (see FIG. 2).

  The rotor 30 includes a shaft portion 31 and a disc portion 32 (see FIG. 2). The shaft portion 31 has a concave supported portion 33 into which the tip of the support portion 15 is fitted (see FIG. 2). The rotor 30 is rotatably supported on the outer peripheral surfaces of the supported portion 33 and the shaft portion 31 by a support portion 15 provided in the housing 10 and a hole portion 21 provided in the plug 20 (see FIG. 2). The disc part 32 has an outer diameter smaller than the inner diameter of the first peripheral wall part 11. In the housing 10, the first surface 32 b of the disk part 32 intersecting the outer peripheral surface 32 a of the disk part 32 is in contact with the inner surface of the plug 20 and intersects the outer peripheral surface 32 a of the disk part 32. The second surface 32c (the surface opposite to the first surface 32b) of the disk portion 32 is disposed so as to contact the outer surface of the coil bobbin 70 (see FIG. 3).

  The magnetorheological fluid 40 is a suspension in which ferromagnetic particles are dispersed in a fluid such as synthetic oil. The magnetorheological fluid 40 is a low-viscosity liquid in the absence of a magnetic field. They are linked to form a cross-linked structure, and have the property that the apparent viscosity increases according to the magnetic field strength. In this embodiment, the magnetorheological fluid 40 is formed between the inner peripheral surface 11a of the first peripheral wall portion 11 that is the inner peripheral surface of the housing 10 and the outer peripheral surface 32a of the disk portion 32 that is the outer peripheral surface of the rotor 30 that faces the inner peripheral surface. The inner surface of the plug 20 and the coil bobbin are two gaps that are formed on the inner surface of the housing 10 (the inner peripheral surface 11a of the first peripheral wall portion 11). The gap 90 is filled by the outer surface of the 70.

  In order to prevent leakage of the magnetorheological fluid 40 from the gap 90, the seal member 50 is provided between the inner surface of the plug 20 and the inner surface of the seat portion 13, the first surface 32 b of the disc portion 32, and the inner surface of the plug 20. Between the second surface 32c of the disc portion 32 and the outer surface of the coil bobbin 70, and between the inner peripheral surface 11a of the first peripheral wall portion 11 and the end surface of the coil bobbin 70 (see FIG. 3). .

  The coil 60 is wound around a coil bobbin 70 disposed around the support portion 15, and a lead wire 80 is connected to the coil 60 (see FIG. 2).

The housing 10 and the rotor 30 described above are preferably formed of a high-density iron-based sintered metal. This is because the iron-based sintered metal has a higher magnetic permeability than other sintered metals. As another forming material of the housing 10 and the rotor 30, a high-density sintered metal mainly composed of pure iron is preferable. This is because a sintered metal containing pure iron as a main component has a higher magnetic permeability than other iron-based sintered metals. When the housing 10 and the rotor 30 are formed of sintered metal, their density is preferably 6 g / cm ³ or more. If it is less than 6 g / cm ^3, there is a high possibility that the magnetorheological fluid 40 leaks to the outside through the housing 10 or the rotor 30. In order to reliably prevent leakage of the magnetorheological fluid 40 to the outside, the density thereof is preferably 7 g / cm ³ or more.

When the housing 10 is formed of sintered metal, the density of the support portion 15 is set to a portion other than the support portion 15 (that is, the first peripheral wall portion 11, the second peripheral wall portion 12, the seat portion 13 and the bottom wall portion 14). It is preferable to set the density lower than the density and impregnate the support portion 15 with the lubricating oil. In this case, the density of the support portion 15 is less than 7 g / cm ³ in order to impregnate the lubricating oil, and the density of portions other than the support portion 15 is 7 g / cm ³ or more in order to prevent leakage of the magnetorheological fluid 40. It is preferable that In this example, the density of the support portion 15 was set to 6.5 to 6.9 g / cm ³ . Accordingly, the rotor 30 can be smoothly rotated without installing a bearing member, and the wear resistance of the support portion 15 and the supported portion 33 can be improved. Moreover, in the present Example, the density of parts other than the support part 15 was 7.2 g / cm < ³ > or more. As a result, leakage of the magnetorheological fluid 40 could be reliably prevented.

  The braking device configured as described above generates a magnetic field by supplying a current to the coil 60 via the lead wire 80, and this magnetic field fills the gap 90 over the entire area of the gap 90. The applied magnetorheological fluid 40 is applied. Since the magnetorheological fluid 40 has the property that the apparent viscosity increases according to the magnetic field strength, the shear stress of the magnetorheological fluid 40 increases as the magnetic field strength increases. Therefore, the braking force for decelerating the rotation speed of the rotating rotor 30 or stopping the rotation of the rotor 30 also increases as the magnetic field strength increases.

  According to the braking device of the present embodiment, the magnetorheological fluid 40 is filled only in the gap 90 where the braking force is substantially generated (that is, the region where the shearing stress of the magnetorheological fluid 40 is generated). Therefore, the amount of use of the magnetorheological fluid 40 can be minimized. Further, since the structure is not filled with the magnetorheological fluid 40 in the space where the braking force is not substantially generated (that is, the region where the shearing stress of the magnetorheological fluid 40 is not generated), the ferromagnetic particles in the fluid are precipitated. As a result, the braking characteristics can be made more stable.

  FIG. 1 is a perspective view illustrating a braking device according to a second embodiment of the present invention, and FIG. 4 is a cross-sectional view illustrating an internal structure of the braking device according to the second embodiment of the present invention.

  The braking device according to the present embodiment is different from the braking device according to the first embodiment in the structure of the housing 10 and the rotor 30.

  That is, in this embodiment, the support portion 15 provided on the bottom wall portion 14 of the housing 10 has the hole portion 18 (see FIG. 4). The hole portion 18 is formed so as to penetrate the support portion 15 and the bottom wall portion 14. In the present embodiment, the shaft portion 31 of the rotor 30 has a shaft-shaped supported portion 33 inserted through the hole portion 18 (see FIG. 4).

The housing 10 and the rotor 30 described above are preferably formed of a high-density iron-based sintered metal as in the first embodiment. Moreover, as another forming material of the housing 10 and the rotor 30, a high-density sintered metal mainly composed of pure iron is preferable. Furthermore, when the housing 10 and the rotor 30 are formed of sintered metal, their density is preferably 6 g / cm ³ or more, and in order to reliably prevent leakage of the magnetorheological fluid 40 to the outside, Their density is preferably 7 g / cm ³ or more.

When the rotor 30 is formed of a sintered metal, the density of the supported part 33 is set lower than the density of the parts other than the supported part 33 (that is, the shaft part 31 and the disk part 32) and is supported. It is preferable to impregnate the part 33 with lubricating oil. In this case, the density of the supported portion 33 is less than 7 g / cm ³ in order to impregnate the lubricating oil, and the density of the portion other than the supported portion 33 is 7 g / cm ³ in order to prevent leakage of the magnetorheological fluid 40. It is preferable to set it to ³ or more. In the present embodiment, the density of the supported portion 33 is set to 6.5 to 6.9 g / cm ³ . Accordingly, the rotor 30 can be smoothly rotated without installing a bearing member, and the wear resistance of the support portion 15 and the supported portion 33 can be improved. In the present embodiment, the density of the portion other than the supported portion 33 is set to 7.2 g / cm ³ or more. As a result, leakage of the magnetorheological fluid 40 could be reliably prevented.

  In the braking device according to this embodiment, the gap 90 filled with the magnetorheological fluid 40 is configured in the same manner as in the first embodiment. Therefore, the amount of use of the magnetorheological fluid 40 can be minimized. Further, since the structure in which the magnetic viscous fluid 40 is not filled in the space where the braking force is not substantially generated (the region where the shear stress of the magnetic viscous fluid 40 is not generated), the ferromagnetic particles in the fluid are difficult to precipitate, As a result, the braking characteristic can be further stabilized.

DESCRIPTION OF SYMBOLS 10 Housing 11 1st surrounding wall part 12 2nd surrounding wall part 13 Seat part 14 Bottom wall part 15 Support part 16 Flange part 17 Hole part 18 Hole part 20 Plug 21 Hole part 30 Rotor 31 Shaft part 32 Disc part 33 Supported part 40 Magnetorheological fluid 50 Seal member 60 Coil 70 Coil bobbin 80 Lead wire 90 Air gap

Claims (7)

A hollow housing;
A rotor rotatable within the housing;
A gap formed between the inner peripheral surface of the housing and the outer peripheral surface of the rotor facing the housing, and two openings facing each other are closed by a surface intersecting the inner peripheral surface of the housing. Gaps,
A magnetorheological fluid filling the gap;
A seal member for preventing leakage of the magnetorheological fluid from the gap;
A braking device comprising: a coil disposed inside the housing and generating a magnetic field applied to the magnetorheological fluid.   The braking device according to claim 1, wherein the housing and the rotor are formed of a high-density iron-based sintered metal.   The braking device according to claim 1, wherein the housing and the rotor are formed of a high-density sintered metal containing pure iron as a main component.   The housing has a support portion for supporting the rotor, the density of the support portion is set lower than the density of a portion other than the support portion of the housing, and the support portion is impregnated with lubricating oil. Item 4. The braking device according to item 2 or 3. The braking device according to claim 4, wherein the density of the support portion is less than 7 g / cm ³ , and the density of the portion other than the support portion of the housing is 7 g / cm ³ or more.   The housing has a support part for supporting the rotor, the rotor has a supported part in contact with the support part, and the density of the supported part is higher than the density of a part other than the supported part of the rotor. The braking device according to claim 2 or 3, wherein the braking device is set low and the supported portion is impregnated with lubricating oil. The braking device according to claim 6, wherein the density of the supported portion is less than 7 g / cm ³ , and the density of the portion other than the supported portion of the rotor is 7 g / cm ³ or more.

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