JP2013119806A - Fluid brake device and valve timing adjusting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance durability, and to stabilize brake characteristics.SOLUTION: A seal structure 160 includes: a magnetic flux guide 174 to guide magnetic flux to a brake shaft 131 through a seal gap 176gs formed in a space with respect to the brake shaft 131 so that it communicates with a fluid chamber 114 in which a magnetic viscous fluid 140 is encapsulated; a permanent magnet 173 located adjacent to the outside of a casing of the magnetic flux guide 174 and generating the guide flux acting on the brake shaft 131 from the flux guide 174; a liquid seal member 180 to seal the space with respect to the brake shaft 131 liquid-tightly in a position outside the casing rather than the permanent magnet 173; an intermediate fluid 190 as a liquid of a non-magnetic type to fill an intermediate chamber 178 interposed between the seal gap 176gs and the seal member 180; and a flux stopper 176 located adjacent to the outside of the casing of a flux guide projection part 174p of the magnetic flux guide 174 protruding inward rather than the permanent magnet 173 for restricting flux passage to the intermediate chamber 178 formed in the space with respect to the brake shaft 131.

Description

  The present invention relates to a fluid brake device and a valve timing adjusting device including the fluid brake device.

  2. Description of the Related Art Conventionally, a fluid brake device that variably controls the viscosity of a magnetorheological fluid by passing a magnetic flux through the magnetorheological fluid that is sealed in a fluid chamber inside a housing and is in contact with a brake rotor is known. Since this type of fluid brake device can apply brake torque to the brake rotor with relatively small electric power, for example, the relative phase between the crankshaft and the camshaft that determines the valve timing of the internal combustion engine (hereinafter referred to as “engine phase”). ) Is suitable for a valve timing adjusting device or the like that adjusts according to the brake torque.

  As a type of fluid brake device, Patent Document 1 discloses a device that seals between a brake shaft that penetrates the housing in and out of the brake rotating body in the axial direction and the housing with a seal structure. ing. Specifically, in the fluid brake device of Patent Document 1, a permanent magnet and a magnetic flux guide constituting a seal structure are provided in a form surrounding the outer peripheral side of the brake shaft in the housing. Under such a configuration, the magnetic flux generated by the permanent magnet is guided from the magnetic flux guide to the brake shaft through a seal gap communicating with the fluid chamber between the magnetic flux guide and the brake shaft. As a result, the magnetorheological fluid flowing from the fluid chamber into the seal gap through which the magnetic flux passes is trapped in the form of a film by receiving the magnetic flux and increasing the viscosity.

  The seal film formed in the seal gap in this way exhibits a so-called self-seal function in which the fluid itself suppresses the flow of the magnetorheological fluid from the inside of the housing to the outside of the housing in the axial direction of the brake shaft. obtain. Therefore, it is possible to avoid a change in brake characteristics due to leakage of the magnetorheological fluid from the fluid chamber. Further, according to the seal film made of a magnetorheological fluid, it is possible to improve the durability by reducing the frictional resistance applied to the brake shaft.

JP 2010-121614 A

  However, as a result of the study by the present inventors, it has been found that the fluid brake device of Patent Document 1 may cause a change in brake characteristics due to the following factors. The reason for this is that among the magnetorheological fluids in which magnetic particles are dispersed in a non-magnetic base liquid, the base liquid that is not affected by the magnetic flux in the seal gap has the effect of the pressure rising with the temperature in the fluid chamber. By receiving, it is easy to come out to the outside of the housing. Here, the escape of the base liquid not only leads to the alteration of the magnetorheological fluid itself, but also accelerates the alteration due to the flow involving the magnetic particles in the magnetorheological fluid. Therefore, such alteration of the magnetorheological fluid is undesirable because it reduces the self-sealing function and causes a change in brake characteristics.

  Therefore, the present inventors are sandwiched between a liquid seal member that liquid-tightly seals between the housing and the brake shaft on the outside of the housing from the magnetic flux guide and the permanent magnet, and a seal gap formed by the magnetic flux guide. A prior invention was created to fill the intermediate chamber with an intermediate fluid that is a non-magnetic liquid (Japanese Patent Application No. 2011-212130). In this prior invention, the pressure in the fluid chamber propagates through the base liquid in the magnetorheological fluid in the seal gap and the intermediate fluid in the intermediate chamber, and is received by the liquid seal member. According to such a catching action, it is possible to suppress the base liquid from entraining the magnetic particles and coming out from the seal gap to the intermediate chamber, so that it is difficult for the magnetorheological fluid to be altered due to the removal. At the same time, the intermediate fluid, which is a non-magnetic liquid, is hardly attracted to the seal gap by being magnetically attracted from the intermediate chamber and mixed with the base liquid. Accordingly, it is possible to avoid a decrease in the self-sealing function due to the alteration of the magnetorheological fluid, and hence a change in brake characteristics.

  Moreover, in the prior invention, even if the base liquid entrains the magnetic particles and escapes from the seal gap to the intermediate chamber, the magnetic particles are liquid according to the separation distance between the seal gap and the liquid seal member sandwiching the intermediate chamber. It becomes difficult to reach the seal member. Therefore, even if the surface pressure is reduced at the seal interface between the liquid seal member and the brake shaft, it is possible to avoid the situation where the magnetic particles enter the seal interface and increase the frictional resistance. You can contribute.

  Although it is a prior invention that brings about these effects, the present inventors have discovered that the following improvements exist as a result of further research. The improvement is due to the fact that the radial width of the intermediate chamber is larger than the radial width of the seal gap on the outside of the casing of the protruding portion of the magnetic flux guide protruding from the permanent magnet. The Taylor vortex or turbulence accompanying the rotation of the brake shaft is generated in the intermediate chamber. Such Taylor vortex flow or turbulent flow generates a shearing force that peels off the magnetic particles from the seal film formed by the magnetorheological fluid in the seal gap, and the magnetic particles escape to the intermediate chamber and liquid seal. This is undesirable because it leads to the member.

  The present invention has been made in view of the improvements described above, and an object thereof is to provide a fluid brake device that improves durability and stabilizes brake characteristics, and a valve timing adjustment device including the fluid brake device. It is to provide.

According to the first aspect of the present invention, a magnetic material in which magnetic particles are dispersed in a housing that forms a fluid chamber therein and a non-magnetic base liquid is enclosed in the fluid chamber and the viscosity changes according to the passing magnetic flux. A fluid chamber having viscosity control means for variably controlling the viscosity of the magnetorheological fluid by passing the magnetic flux through the magnetorheological fluid in the fluid chamber and the fluid chamber, and a brake shaft penetrating the housing in and out in the axial direction; A fluid brake device comprising: a brake rotating body to which a brake torque according to the viscosity of the magnetorheological fluid is input by contacting with the magnetorheological fluid; and a seal structure that seals between the housing and the brake shaft. And
The seal structure surrounds the outer peripheral side of the brake shaft in the housing, forms a seal gap communicating with the fluid chamber between the brake shaft, a magnetic flux guide that guides the magnetic flux to the brake shaft through the seal gap, and a magnetic flux in the housing A permanent magnet that surrounds the outer periphery of the brake shaft adjacent to the outside of the housing of the guide and generates magnetic flux that is guided from the magnetic flux guide to the brake shaft by the magnetic pole, and is disposed on the outside of the housing in the housing rather than the permanent magnet A liquid seal member that comes into contact with the brake shaft from the outer peripheral side and seals the space between the brake shaft in a liquid-tight manner, and an intermediate fluid that fills the seal gap and the intermediate chamber sandwiched between the liquid seal members as a nonmagnetic liquid In the case, the outer peripheral side of the brake shaft is formed adjacent to the outer side of the case adjacent to the outer side of the protruding part of the magnetic flux guide that protrudes to the inner peripheral side of the permanent magnet. And a magnetic flux stopper for restricting the passage of magnetic flux that the intermediate chamber has.

  In the housing of the present invention, the magnetic flux stopper surrounding the outer peripheral side of the brake shaft has a predetermined outer diameter corresponding to the radial thickness adjacent to the outer side of the outer portion of the protruding portion of the magnetic flux guide protruding to the inner peripheral side from the permanent magnet. The radial width of the intermediate chamber formed between the brake shaft and the brake shaft can be reduced. In the intermediate chamber in which the radial width can be reduced in this way, Taylor vortex or turbulence accompanying rotation of the brake shaft is reduced, so that the magnetic particles are peeled off from the seal film formed by the magnetorheological fluid in the seal gap. Generation of such a shearing force is suppressed. In addition, since the magnetic flux stopper can restrict the passage of the magnetic flux from the magnetic flux guide to the intermediate chamber, the magnetic particles are prevented from being drawn into the intermediate chamber by the magnetic flux. According to these, even when the magnetic particles escape to the intermediate chamber and cause the alteration of the magnetorheological fluid forming the seal film, the magnetic particles that have escaped to the intermediate chamber reach the liquid seal member and cause friction at the seal interface. The situation of increasing resistance can also be avoided. Therefore, stabilization of the brake characteristics by avoiding alteration of the magnetorheological fluid can be achieved together with improvement in durability by avoiding an increase in frictional resistance.

  According to the invention of claim 2, the seal structure is disposed between the permanent magnet and the liquid seal member in the housing, surrounds the outer peripheral side of the brake shaft, and protrudes to the inner peripheral side from the permanent magnet. An outer peripheral member that forms an intermediate chamber with the brake shaft is further included. In the housing of the present invention, the outer peripheral member surrounding the outer peripheral side of the brake shaft is between the permanent magnet and the liquid seal member and the brake shaft having a predetermined outer diameter by a protruding height that protrudes inward from the permanent magnet. The radial width of the intermediate chamber formed therebetween can be reduced. In the intermediate chamber in which the radial width can be reduced by the outer peripheral member in this way, the function of reducing the Taylor vortex flow or turbulent flow is enhanced in combination with the radial width reduction action by the magnetic flux stopper. According to this, it is possible to reliably suppress the generation of the shearing force that peels off the magnetic particles from the seal film, thereby achieving both stabilization of the brake characteristics and improvement of durability.

  According to the third aspect of the invention, the magnetic flux stopper has a radial thickness equal to the protruding height of the protruding portion of the magnetic flux guide, thereby forming an intermediate chamber having a radial width equal to the seal gap. The magnetic flux stopper according to the present invention reduces the radial width of the intermediate chamber to a width equal to the seal gap by the radial thickness equal to the protruding height of the protruding portion of the magnetic flux guide, thereby reducing the Taylor vortex flow or turbulent flow. Can increase. According to this, it is possible to reliably suppress the generation of the shearing force that peels off the magnetic particles from the seal film, thereby achieving both stabilization of the brake characteristics and improvement of durability.

  According to invention of Claim 4, a magnetic flux stopper covers the whole area of the axial direction of a permanent magnet from an inner peripheral side. The magnetic flux stopper according to the present invention can reduce the radial width of the intermediate chamber in a long range over the entire axial direction of the permanent magnet covering from the inner peripheral side, so that Taylor vortex flow or turbulent flow in the intermediate chamber is reduced. Function is enhanced. According to this, it is possible to reliably suppress the generation of the shearing force that peels off the magnetic particles from the seal film, thereby achieving both stabilization of the brake characteristics and improvement of durability.

  According to invention of Claim 5, a magnetic flux stopper covers a part of axial direction containing an adjacent edge part with a magnetic flux guide among permanent magnets from an inner peripheral side. The magnetic flux stopper according to the present invention covers the part of the inner peripheral side permanent magnet in the axial direction including the adjacent end portion with the magnetic flux guide, and draws in the magnetic particles by Taylor vortex or turbulent flow in the intermediate chamber. The radial width can be reduced only in the vicinity of the seal gap. According to this, as much as necessary to stabilize the brake characteristics and improve durability, while reducing the Taylor vortex or turbulence reduction function, the material for forming the magnetic flux stopper added for the reduction function is reduced. It becomes possible.

  According to a sixth aspect of the present invention, the seal structure projects to the outer peripheral side toward the sleeve magnetic flux guide as the magnetic flux guide on the brake shaft, thereby forming an axial magnetic flux guide with the sleeve magnetic flux guide. And the passage of the magnetic flux to the intermediate chamber formed between the sleeve magnetic flux stopper and the sleeve magnetic flux stopper disposed on the inner peripheral side of the sleeve magnetic flux stopper adjacent to the outside of the housing of the axial magnetic flux guide on the brake shaft And an axial magnetic flux stopper for regulating In this invention, the radial thickness of the axial magnetic flux stopper adjacent to the outside of the housing of the axial magnetic flux guide protruding toward the outer peripheral side toward the sleeve magnetic flux guide in the brake shaft, and the radial thickness of the sleeve magnetic flux stopper, The radial width of the intermediate chamber between the magnetic flux stoppers can be reduced. In the intermediate chamber in which the radial width can be reduced in this way, Taylor vortex flow or turbulent flow associated with rotation of the brake shaft is reduced, and therefore, from the seal film formed by the magnetorheological fluid at the seal gap between the magnetic flux stoppers. Generation of shearing force that peels off the magnetic particles is suppressed. Moreover, since each magnetic flux stopper can restrict the passage of magnetic flux from the adjacent magnetic flux guide to the intermediate chamber, the magnetic particles are prevented from being drawn into the intermediate chamber by the magnetic flux. According to these, both the situation that causes the alteration of the magnetorheological fluid and the situation that increases the frictional resistance of the seal interface by the liquid seal member are enhanced together with the stabilization of the brake characteristics and the improvement of the durability. It becomes possible.

  According to the invention described in claim 7, the intermediate fluid is a liquid different from the base liquid. In the present invention, the base liquid becomes difficult to mix with the heterogeneous intermediate fluid, and, in combination with the action of receiving the pressure in the fluid chamber, the escape from the seal gap is suppressed. Therefore, it is possible to improve the reliability of the stabilization of the brake characteristics due to the alteration of the magnetorheological fluid.

  According to the invention described in claim 8, the base liquid is one of a polar liquid and a nonpolar liquid, and the intermediate fluid is the other of the polar liquid and the nonpolar liquid. In the present invention, the base liquid that is one of a polar liquid and a nonpolar liquid that generate a repulsive force between each other repels the intermediate fluid that is the other, thereby causing the intermediate fluid to escape from the seal gap. Mixing is suppressed. In other words, the intermediate fluid is repelled from the base liquid and mixed in the seal gap is suppressed. As a result of these mixing suppression effects, stabilization of the brake characteristics due to alteration of the magnetorheological fluid can be achieved with high reliability. In addition, the magnetic particles to which the base liquid adheres in the magnetorheological fluid can be prevented from reaching the liquid seal member due to repulsion with the intermediate fluid in the intermediate chamber, which can contribute to improvement in durability.

  According to the invention described in claim 9, the intermediate fluid is the same liquid as the base liquid. In the seal gap of the present invention, even if the intermediate fluid is mixed with the base liquid as the same liquid, the magnetic viscous fluid is not altered by the mixing itself. Therefore, it is possible to improve the reliability of the stabilization of the brake characteristics due to the alteration of the magnetorheological fluid.

The invention according to claim 10 is a valve timing adjusting device for adjusting a valve timing of a valve that opens and closes a camshaft by torque transmission from a crankshaft in an internal combustion engine,
The fluid brake device according to any one of claims 1 to 9, an engine connected to a brake shaft outside the housing of the fluid brake device, and in accordance with a brake torque input to a brake rotating body of the fluid brake device A phase adjustment mechanism for adjusting the phase.

  According to the seal structure of the fluid brake device provided in the present invention, it is possible to achieve stabilization of the brake characteristics by avoiding the alteration of the magnetorheological fluid and maintain the adjustment accuracy of the engine phase that depends on the characteristics. . Furthermore, in the seal gap in which the seal film of the magnetorheological fluid is formed in the seal structure, the escape of the base liquid entraining the magnetic particles and the escape of the magnetic particles due to Taylor vortex or turbulent flow are suppressed. It is not necessary to increase the density of the passing magnetic flux necessary for capturing particles. Therefore, the seal film formed by the magnetorheological fluid that receives the relatively low density passing magnetic flux has a small frictional resistance applied to the brake shaft, so that not only the durability is improved but also the internal combustion engine due to the frictional resistance. It is also possible to avoid the torcross that causes a reduction in fuel consumption.

It is a figure which shows the valve timing adjustment apparatus provided with the fluid brake device by 1st embodiment of this invention, Comprising: It is the II sectional view taken on the line of FIG. It is the II-II sectional view taken on the line of FIG. It is the III-III sectional view taken on the line of FIG. It is a schematic diagram for demonstrating the characteristic of the magnetorheological fluid of FIG. It is sectional drawing which expands and shows the fluid brake device of FIG. It is sectional drawing which expands and shows the seal structure of FIG. It is sectional drawing for demonstrating the characteristic of the seal structure of FIG. In the seal structure of the fluid brake device by 1st-3rd embodiment of this invention, it is a schematic diagram which shows the structural component of the base liquid of a magnetorheological fluid, and an intermediate fluid. It is sectional drawing which expands and shows the fluid brake device by 2nd embodiment of this invention. It is sectional drawing which expands and shows the seal structure of FIG. It is sectional drawing which expands and shows the seal structure of the fluid brake device by the modification of 1st embodiment of this invention. It is sectional drawing which expands and shows the seal structure of the fluid brake device by the modification of 1st embodiment of this invention. It is sectional drawing which expands and shows the fluid brake device by the modification of 1st embodiment of this invention. It is sectional drawing which expands and shows the fluid brake device by the modification of 1st embodiment of this invention. It is sectional drawing which expands and shows the fluid brake device by the modification of 1st embodiment of this invention.

  Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. In addition, the overlapping description may be abbreviate | omitted by attaching | subjecting the same code | symbol to the corresponding component in each embodiment. When only a part of the configuration is described in each embodiment, the configuration of the other embodiment described above can be applied to the other part of the configuration. In addition, not only combinations of configurations explicitly described in the description of each embodiment, but also the configurations of a plurality of embodiments can be partially combined even if they are not explicitly specified unless there is a problem with the combination. .

(First embodiment)
FIG. 1 shows a valve timing adjusting device 1 including a fluid brake device 100 according to a first embodiment of the present invention. A valve timing adjusting device 1 mounted on a vehicle is provided in a transmission system that transmits engine torque from a crankshaft (not shown) of an internal combustion engine to a camshaft 2. Here, the camshaft 2 opens and closes an intake valve (not shown) of the “valve” of the internal combustion engine by transmitting engine torque, and the valve timing adjusting device 1 adjusts the valve timing of the intake valve. .

  As shown in FIGS. 1 to 3, the valve timing adjusting device 1 is a combination of a fluid brake device 100, an energization control circuit 200, a phase adjusting mechanism 300, and the like, and an engine having a relative phase of the camshaft 2 with respect to the crankshaft The desired valve timing is achieved by adjusting the phase.

(Fluid brake device)
The electric fluid brake device 100 shown in FIG. 1 includes a housing 110, a brake rotating body 130, a magnetorheological fluid 140, a solenoid coil 150, and a seal structure 160.

  The hollow casing 110 as a whole has a fixing member 111 and a cover member 112. A fixing member 111 formed in a stepped cylindrical shape by a magnetic material is fixed to a fixing node (not shown) such as a chain case of an internal combustion engine. The cover member 112 formed in a circular dish shape with a magnetic material is disposed on the opposite side of the phase adjustment mechanism 300 with the fixing member 111 sandwiched in the axial direction. The cover member 112 fitted and fixed in a liquid-tight manner to the fixing member 111 forms a space between the fixing member 111 as a fluid chamber 114 inside the housing 110.

  The brake rotating body 130 includes a brake shaft 131 and a brake rotor 132. A columnar brake shaft 131, most of which is made of a magnetic material, is disposed coaxially with the constituent members 111 and 112 of the housing 110. The brake shaft 131 penetrates the fixing member 111 on the phase adjustment mechanism 300 side of the housing 110 inward and outward in the axial direction, so that the axial end protruding to the outside of the housing 110 is connected to the phase adjustment mechanism 300. It is connected. An intermediate portion in the axial direction of the brake shaft 131 is rotatably supported by a bearing 116 provided on the fixed member 111 of the housing 110. With these configurations, the brake rotator 130 rotates in a certain direction (counterclockwise in FIGS. 2 and 3) when engine torque output from the crankshaft is transmitted from the phase adjustment mechanism 300 during operation of the internal combustion engine. To do.

  As shown in FIG. 1, the brake rotor 132 formed in the shape of an annular plate with a magnetic material protrudes from the axial end on the opposite side of the brake shaft 131 to the outer side of the phase adjustment mechanism 300, It is housed in a fluid chamber 114 inside the housing 110. With this housing configuration, the fluid chamber 114 forms a portion sandwiched between the brake rotor 132 and the fixing member 111 in the axial direction as a first magnetic gap 114g1, and a portion sandwiched between the brake rotor 132 and the cover member 112 in the axial direction. The second magnetic gap 114g2 is formed.

  A magnetorheological fluid 140 is sealed in the fluid chamber 114 including the magnetic gaps 114g1 and 114g2. The magnetorheological fluid 140, which is a kind of functional fluid, is formed by dispersing powdery magnetic particles such as carbonyl iron in a non-magnetic base liquid (see FIG. 8) in a suspended state. The magnetorheological fluid 140 has a characteristic that the yield stress increases in proportion to the viscosity when the apparent viscosity rises and changes as shown in FIG. 4 following the density of the magnetic flux passing therethrough.

  As shown in FIG. 1, the solenoid coil 150 is formed by winding a metal wire around a resin bobbin 151 and is coaxially disposed on the outer peripheral side of the brake rotor 132. The solenoid coil 150 is held by the casing 110 while being sandwiched between the fixing member 111 and the cover member 112. By energizing the solenoid coil 150 having such a holding configuration, in this embodiment, a magnetic flux that sequentially passes through the fixing member 111, the first magnetic gap 114g1, the brake rotor 132, the second magnetic gap 114g2, and the cover member 112 is generated. .

  Therefore, when the solenoid coil 150 generates magnetic flux by energization while the brake rotating body 130 is rotating, the generated magnetic flux passes through the magnetorheological fluid 140 in the magnetic gaps 114g1 and 114g2 in the fluid chamber 114. As a result, the brake rotor 132 that contacts the magnetorheological fluid 140 whose viscosity has changed has a brake torque that brakes the brake rotor 130 by the action of viscous resistance in the direction opposite to the rotational direction (clockwise in FIGS. 2 and 3). Given. As described above, in the present embodiment, the energized solenoid coil 150 allows magnetic flux to pass through the magnetorheological fluid 140 in the fluid chamber 114, so that the brake torque corresponding to the viscosity of the fluid 140 can be input to the brake rotating body 130. It has become.

  As shown in FIGS. 1 and 5, the seal structure 160 is provided at a location between the axial fluid chamber 114 and the bearing 116 in the housing 110. The seal structure 160 suppresses leakage of the magnetorheological fluid 140 to the outside of the casing 110 by sealing between the fixing member 111 of the casing 110 and the brake shaft 131 of the brake rotating body 130. .

(Energization control circuit)
An energization control circuit 200 shown in FIG. 1 is mainly composed of a microcomputer, is disposed outside the fluid brake device 100, and is electrically connected to the solenoid coil 150 and the vehicle battery 4. The energization control circuit 200 that receives power from the battery 4 during operation of the internal combustion engine generates a magnetic flux that passes through the magnetorheological fluid 140 by controlling the energization current to the solenoid coil 150. Accordingly, at this time, the viscosity of the magnetorheological fluid 140 is variably controlled, and the brake torque input to the brake rotating body 130 increases or decreases following the energization current to the solenoid coil 150. As described above, in the present embodiment, the energization control circuit 200 and the solenoid coil 150 together constitute “viscosity control means”.

(Phase adjustment mechanism)
As shown in FIGS. 1 to 3, the phase adjustment mechanism 300 includes a drive rotator 10, a driven rotator 20, an assist member 30, a planet carrier 40, and a planetary gear 50.

  As shown in FIGS. 1 and 2, the drive rotator 10 is formed of a metal in a cylindrical shape. The peripheral wall portion of the drive rotator 10 forms a drive-side internal gear portion 14 having a tip circle with a diameter smaller than the root circle, and a plurality of sprocket teeth 16 projecting to the outer peripheral side. The drive rotator 10 is linked to the crankshaft by spanning a timing chain (not shown) between the sprocket teeth 16 and the crankshaft teeth. During the operation of the internal combustion engine in this connection mode, the engine torque output from the crankshaft is transmitted, so that the drive rotor 10 is linked to the crankshaft in a certain direction (counterclockwise in FIGS. 2 and 3). Rotate.

  As shown in FIGS. 1 and 3, the driven rotator 20 is formed of a metal in a bottomed cylindrical shape and is coaxially disposed on the inner peripheral side of the drive rotator 10. The peripheral wall portion of the driven rotor 20 forms a driven side internal gear portion 22 having a tooth tip circle having a smaller diameter than the root circle. The bottom wall portion of the driven rotor 20 is coaxially connected to the cam shaft 2. With this connection form, the driven rotor 20 during operation of the internal combustion engine can rotate relative to the drive rotor 10 while rotating in a fixed direction (counterclockwise in FIGS. 2 and 3) in conjunction with the camshaft 2. It has become.

  As shown in FIG. 1, the assist member 30 made of a metal torsion coil spring is coaxially disposed on the inner peripheral side of the drive rotating body 10. The assist member 30 biases the driven rotating body 20 toward the retard side with respect to the driving rotating body 10 by being torsionally deformed between both end portions 31 and 32 respectively engaged with the rotating bodies 10 and 20.

  As shown in FIGS. 1 to 3, the planet carrier 40 is formed of a metal in a cylindrical shape, and is coaxially connected to the brake shaft 131 of the brake rotating body 130 via a joint 43. The planetary carrier 40 during operation of the internal combustion engine can rotate relative to the drive rotating body 10 while rotating in a fixed direction (counterclockwise direction in FIGS. 2 and 3) integrally with the brake rotating body 130 by this connection form. ing.

  The peripheral wall portion of the planetary carrier 40 forms a bearing portion 46 for bearing the planetary gear 50. A cylindrical surface-shaped bearing portion 46 that is eccentrically arranged with respect to the rotary bodies 10 and 20 and the brake shaft 131 is coaxially fitted in the center hole 51 of the planetary gear 50 via the planetary bearing 48. The planetary gear 50 is capable of planetary movement by such a fitting form. Here, the planetary motion refers to a motion in which the planetary gear 50 revolves around the eccentric center line of the bearing portion 46 with respect to the brake shaft 131 and revolves in the rotational direction of the planetary carrier 40. Accordingly, when the planetary carrier 40 rotates relative to the drive rotor 10 in the revolving direction of the planetary gear 50, the planetary gear 50 performs planetary motion.

  The planetary gear 50 is formed of a metal in a stepped cylindrical shape. The peripheral wall portion of the planetary gear 50 forms external gear portions 52 and 54 having tooth tip circles larger in diameter than the root circle. The drive side external gear portion 52 is disposed on the inner peripheral side of the drive side internal gear portion 14 and meshes with the internal gear portion 14. The driven-side external gear portion 54 is disposed on the inner peripheral side of the driven-side internal gear portion 22 and meshes with the internal gear portion 22.

  With the above configuration, the phase adjustment mechanism 300 changes the engine phase in accordance with the brake torque input to the brake rotator 130 and the assist torque of the assist member 30 that acts on the brake rotator 130 in the direction opposite to the brake torque. adjust. Specifically, when the brake rotator 130 realizes rotation at the same speed as the drive rotator 10 by holding brake torque or the like, the planet carrier 40 does not rotate relative to the rotator 10. As a result, the planetary gear 50 rotates with the rotating bodies 10 and 20 without planetary motion, so that the engine phase is maintained. On the other hand, when the brake rotator 130 realizes rotation at a lower speed than the drive rotator 10 against the assist torque due to an increase in brake torque or the like, the planetary carrier 40 rotates relative to the retard side with respect to the rotator 10. . As a result, the planetary gear 50 moves in a planetary motion and the driven rotator 20 rotates relative to the drive rotator 10 toward the advance side, so that the engine phase advances. On the other hand, when the brake rotating body 130 receives the assist torque and realizes rotation at a speed higher than that of the driving rotating body 10 due to a decrease in brake torque or the like, the planetary carrier 40 relatively rotates toward the advance side with respect to the rotating body 10. . As a result, the planetary gear 50 moves in a planetary motion and the driven rotator 20 rotates relative to the drive rotator 10 toward the retard side, so that the engine phase is retarded.

(Seal structure)
Hereinafter, details of the seal structure 160 will be described. In the following description, the inside of the casing 110 forming the fluid chamber 114 is simply referred to as “inside the casing”, and the outside of the casing 110 in which the phase adjustment mechanism 300 is disposed is simply referred to as “outside the casing”. And In the following description, the common axial direction, radial direction, and rotational direction of the casing 110 and the brake shaft 131 are simply referred to as “radial direction”, “axial direction”, and “rotational direction”, respectively.

  As shown in FIGS. 1 and 5, the seal structure 160 for isolating the fluid chamber 114 in which the magnetorheological fluid 140 is sealed inside the casing from the outside of the casing includes a magnetic seal shaft 162, a magnetic seal sleeve 170, The liquid seal member 180 and the intermediate fluid 190 are included.

  As shown in FIGS. 5 and 6, the magnetic seal shaft 162 provided on the brake shaft 131 has a pair of shaft magnetic flux guides 164 and 165, a shaft magnetic flux stopper 166 and a shaft extra stopper 167.

  The axial magnetic flux guides 164 and 165 are formed in substantially the same annular plate shape by a magnetic material such as the same steel as the columnar shaft main body 133 of the brake shaft 131. Each of the axial magnetic flux guides 164 and 165 protrudes further from the outer peripheral portion 133o of the shaft main body 133 to the outer peripheral side, with one 164 positioned on the outside of the housing with respect to the other 165. Here, the axial magnetic flux guides 164 and 165 coaxial with the shaft main body 133 have a substantially constant outer diameter φshg in the axial direction and the rotational direction.

  The axial magnetic flux stopper 166 is formed in a cylindrical shape by a nonmagnetic material such as austenitic stainless steel that can restrict the passage of magnetic flux. The shaft magnetic flux stopper 166 is coaxially fitted and fixed to the outer peripheral portion 133 o of the shaft main body 133 between the shaft magnetic flux guides 164 and 165. In this embodiment, in particular, the axial magnetic flux stopper 166 is sandwiched between the axial magnetic flux guides 164 and 165 in the axial direction, so that the outer side of the axial magnetic flux guide 164 and the inner side of the axial magnetic flux guide 165 are adjacent to each other. Thus, the shaft main body 133 is covered from the outer peripheral side. Here, in the axial magnetic flux stopper 166, the radial thickness Tshs substantially constant in the axial direction and the rotational direction is set to be substantially equal to the protruding height Hshg of the axial magnetic flux guides 164 and 165. With this setting, the outer diameter φshs of the axial magnetic flux stopper 166 is substantially constant in the axial direction and the rotational direction.

  The shaft extra stopper 167 is formed in an annular plate shape by a nonmagnetic material such as austenitic stainless steel capable of restricting the passage of magnetic flux. The shaft extra stopper 167 is coaxially fitted and fixed to the outer peripheral portion 133 o of the shaft main body 133 on the outer side of the housing than the shaft magnetic flux guide 165. In this embodiment, in particular, the shaft extra stopper 167 is sandwiched in the axial direction between the shaft magnetic flux guide 165 and the liquid seal member 180, so that the housing outer side of the shaft magnetic flux guide 165 and the housing of the liquid seal member 180. The shaft main body 133 is covered from the outer peripheral side adjacent to the inner side. Here, in the shaft extra stopper 167, the radial thickness Tsh substantially constant in the axial direction and the rotational direction is set to be substantially equal to the protruding height Hshg of the axial magnetic flux guide 165. With this setting, the outer diameter φsh of the shaft extra stopper 167 is substantially constant in the axial direction and the rotational direction.

  The magnetic seal sleeve 170 provided in the housing 110 includes a magnetic shield 172, a permanent magnet 173, a pair of sleeve magnetic flux guides 174 and 175, a sleeve magnetic flux stopper 176, and a sleeve extra stopper 177.

  The magnetic shield 172 is formed in a bottomed cylindrical shape by a nonmagnetic material such as austenitic stainless steel that can restrict the passage of magnetic flux. The magnetic shield 172 is arranged coaxially with the brake shaft 131, and surrounds the outer peripheral side of the magnetic seal shaft 162 provided on the shaft 131 along the rotation direction. The magnetic shield 172 has an inner peripheral portion of the fixing member 111 in the housing 110 in a state where the opening of the annular wall portion 172r and the bottom wall portion 172b are directed to the housing outer side and the housing inner side in the axial direction, respectively. 111i is fitted and fixed.

  The permanent magnet 173 is formed in a cylindrical shape by, for example, a ferrite magnet. The permanent magnet 173 is coaxially fitted and fixed to the annular wall portion 172r of the magnetic shield 172 so as to surround the outer peripheral side of the axial magnetic flux stopper 166 of the magnetic seal shaft 162 of the brake shaft 131 along the rotation direction. Yes. The permanent magnet 173 has magnetic poles N and S having opposite polarities at both ends in the axial direction, and generates a magnetic flux MF between the magnetic poles N and S as schematically shown in FIG.

  As shown in FIGS. 5 and 6, the pair of sleeve magnetic flux guides 174 and 175 are formed in a substantially identical annular plate shape by a magnetic material such as carbon steel. The sleeve magnetic flux guides 174 and 175 are coaxially fitted and fixed to the annular wall portion 172r of the magnetic shield 172 so that the outer peripheral sides of the corresponding magnetic flux guides 164 and 165 of the magnetic seal shaft 162 are rotated in the rotational direction. Surrounding along. Particularly in the present embodiment, the sleeve magnetic flux guides 174 and 175 holding the permanent magnets 173 in the axial direction respectively form projecting portions 174p and 175p that protrude to the inner peripheral side of the permanent magnet 173. ing. Here, in the protruding portions 174p and 175p of the sleeve magnetic flux guides 174 and 175, the substantially constant inner diameter φslg in the axial direction and the rotational direction is set larger than the outer diameter φshg of the corresponding axial magnetic flux guides 164 and 165, respectively. .

  With such a configuration, the sleeve magnetic flux guide 174 as a “magnetic flux guide” in which the permanent magnet 173 is adjacent to the outside of the housing has a seal gap 176 gs whose radial width Wgs is substantially constant in the axial direction and the rotational direction. It is formed between the axial magnetic flux guide 164. Here, the seal gap 176gs communicates with the fluid chamber 114 inside the housing in the axial direction, and is filled with the magnetorheological fluid 140 in advance. Further, a sleeve magnetic flux guide 175 as an “outer peripheral member” adjacent to the outer side of the casing of the permanent magnet 173 has a trap gap 178 gt having a substantially constant radial width Wgt in the axial direction and the rotational direction, and an axial magnetic flux on the inner peripheral side. It is formed between the guide 165. Here, the trap gap 178gt in which the radial width Wgt is substantially equal to the radial width Wgs of the seal gap 176gs is filled in advance with the intermediate fluid 190 as a part of the intermediate chamber 178 of the present embodiment.

  The sleeve magnetic flux stopper 176 is formed in a cylindrical shape by a nonmagnetic material such as austenitic stainless steel that can restrict the passage of magnetic flux. The sleeve magnetic flux stopper 176 is coaxially fitted and fixed to the inner peripheral portion 173 i of the permanent magnet 173 so as to surround the outer peripheral side of the axial magnetic flux stopper 166 of the magnetic seal shaft 162 along the rotation direction. In this embodiment, in particular, the sleeve magnetic flux stopper 176 is sandwiched in the axial direction between the projecting portions 174p and 175p of the sleeve magnetic flux guides 174 and 175, so that the housing outer side of the projecting portion 174p and the housing inner portion of the projecting portion 175p. Adjacent to the side. Here, in the sleeve magnetic flux stopper 176, the radial thickness Tsls substantially constant in the axial direction and the rotational direction is set to be substantially equal to the protrusion height Hslg of the protrusions 174p and 175p. Therefore, in the sleeve magnetic flux stopper 176 having such a setting, the substantially constant inner diameter φsls in the axial direction and the rotational direction is larger than the outer diameter φshs of the axial magnetic flux stopper 166.

  With such a configuration, the sleeve magnetic flux stopper 176 as a “magnetic flux stopper” that covers the entire axial direction of the permanent magnet 173 from the inner peripheral side has a communication gap 178 gc having a radial width Wgc substantially constant in the axial direction and the rotational direction. It is formed between the stopper 166. Here, the communication gap 178gc in which the radial width Wgs is substantially equal to the radial width Wgs of the seal gap 176gs is also filled in advance with the intermediate fluid 190 as a part of the intermediate chamber 178 of this embodiment.

  The sleeve extra stopper 177 is formed in an annular plate shape by a nonmagnetic material such as austenitic stainless steel that can restrict the passage of magnetic flux. The sleeve extra stopper 177 is coaxially fitted and fixed to the annular wall portion 172r of the magnetic shield 172 on the outer side of the casing with respect to the sleeve magnetic flux guide 175, so that the outer side of the shaft extra stopper 167 of the magnetic seal shaft 162 is fixed. Is enclosed along the direction of rotation. In this embodiment, in particular, the sleeve extra stopper 177 is sandwiched in the axial direction between the sleeve magnetic flux guide 175 and the liquid seal member 180, so that the housing outer side of the sleeve magnetic flux guide 175 and the housing of the liquid seal member 180. Adjacent to the internal side. Here, the protruding height Hsle of the protruding portion 177p of the sleeve extra stopper 177 that protrudes to the inner peripheral side from the permanent magnet 173 is set to be substantially equal to the protruding height Hslg of the protruding portion 175p. . With this setting, the inner diameter φsle that is substantially constant in the axial direction and the rotational direction in the sleeve extra stopper 177 is larger than the outer diameter φshe of the shaft extra stopper 167.

  With such a configuration, the sleeve extra stopper 177 as an “outer peripheral member” spanning the entire region in the axial direction between the elements 175 and 180 has an extra gap 178ge whose radial width Wge is substantially constant in the axial direction and the rotational direction. 167. Here, the extra gap 178ge in which the radial width Wge is substantially equal to the radial width Wgs of the seal gap 176gs is also filled with the intermediate fluid 190 in advance as a part of the intermediate chamber 178 of this embodiment.

  The liquid seal member 180 is a so-called oil seal formed by attaching a synthetic rubber seal lip 182 to a metal ring 181. The liquid seal member 180 is disposed coaxially with the brake shaft 131 on the outer side of the housing with respect to the magnetic seal sleeve 170, so that the shaft main body 133 of the shaft 131 has an outer side of the housing with respect to the magnetic seal shaft 162. The part which becomes becomes is enclosed from the outer peripheral side along the rotation direction. The seal lip 182 slidably in contact with the outer peripheral portion 133 o of the shaft main body 133 in the liquid seal member 180 is fitted and fixed to the inner peripheral portion 111 i of the fixing member 111 of the housing 110, and each extra stopper 167. , 177 is axially adjacent. Thus, the seal lip 182 extends between the brake shaft 131 and the brake shaft 131 in the rotational direction while the sleeve extra stopper 177 and the sleeve magnetic flux guide 175 as the “outer peripheral member” are held between the permanent magnet 173 in the axial direction. It is liquid-tightly sealed.

  With the above configuration, the gaps 178gc, 178gt, 178ge having substantially the same radial width Wgc, Wgt, Wge are continuous in the axial direction, whereby the intermediate chamber 178 sandwiched between the seal gap 176gs and the liquid seal member 180 is formed. It is formed in a cylindrical shape. As an intermediate fluid 190 pre-enclosed in the intermediate chamber 178 as shown in FIG. 5, in this embodiment, as shown in FIG. 8, a non-magnetic liquid that can maintain a liquid phase under the use environment of the internal combustion engine is used. Of these, a liquid different from the base liquid of the magnetorheological fluid 140 is used.

  Here, as the base liquid of the magnetorheological fluid 140, for example, a nonpolar liquid (hydrophobic liquid) such as oil of the same kind or different kind from the lubricating oil of the internal combustion engine is used. Accordingly, as the intermediate fluid 190, for example, those based on polyethylene glycol monoether having a boiling point of 140 ° C. or higher, or 1-octyl-3-methylimidazolium which is an ionic liquid having a freezing point of −30 ° C. or lower. Polar liquids (hydrophilic liquids) such as bis (trifluoromethylsulfonyl) amide and water will be used.

  In the seal structure 160 as described so far, as schematically shown in FIG. 7, the magnetic flux MF generated by the permanent magnet 173 passes from the sleeve magnetic flux guides 174, 175 to the axial magnetic flux guides through the inner gaps 176gs, 178gt. 164,165. Here, since the sleeve magnetic flux guides 174 and 175 and the axial magnetic flux guides 164 and 165 are brought close to each other by the protruding form toward the inner peripheral side and the outer peripheral side, respectively, the magnetic flux MF to the gaps 176gs and 178gt Centralized guidance is possible.

  Of the gaps 176gs and 178gt through which the magnetic flux MF passes at a high density due to such a guiding action, the magnetorheological fluid 140 in the fluid chamber 114 is magnetically applied to the magnetic particles in the seal gap 176gs communicating with the fluid chamber 114. Easy to flow in by suction. Therefore, in the seal gap 176gs, when the magnetic particles subjected to the action of the passing magnetic flux MF are captured, the viscosity of the magnetorheological fluid 140 increases, and a seal film with high pressure resistance is formed. Therefore, according to the sealing film formed in this way, the self-sealing function that suppresses the flow of the magnetorheological fluid 140 from the inside of the housing to the outside of the housing by the fluid 140 itself can be exhibited.

  Further, in the seal structure 160, the liquid seal member 180 outside the housing with respect to the sleeve magnetic flux guide 174 is in liquid-tight contact with the brake shaft 131 with respect to the intermediate fluid 190 in the intermediate chamber 178 sandwiched between the seal gaps 176gs. The sealing function can be demonstrated. As a result, the intermediate chamber 178 is always filled with the intermediate fluid 190, so that the pressure in the fluid chamber 114 propagates through the base liquid in the magnetorheological fluid 140 and the intermediate fluid 190 in the intermediate chamber 178 in the seal gap 176gs. Thus, the liquid seal member 180 is received. According to this receiving action, the phenomenon in which the base liquid entrains the magnetic particles and escapes from the seal gap 176gs to the intermediate chamber 178 is suppressed. At the same time, the base liquid that is a non-polar liquid that is different from the intermediate fluid 190 that is a polar liquid is repelled by repulsive force, thereby suppressing mixing into the intermediate fluid 190 that may cause the seal liquid to escape from the seal gap 176gs. Is done. In addition, the non-magnetic intermediate fluid 190 is restrained from mixing with the base liquid due to magnetic attraction from the intermediate chamber 178 to the seal gap 176gs in combination with the repulsive action with the base liquid. From these facts, it is possible to avoid the alteration of the magnetorheological fluid 140 due to slipping or mixing at the seal gap 176gs.

  Further, in the seal structure 160, the magnetic particles to which the nonpolar base liquid adheres in the magnetorheological fluid 140 repels the polar intermediate fluid 190, so that the magnetic particles are prevented from coming out to the intermediate chamber 178 by being caught in the base liquid. Also, reaching the liquid seal member 180 is suppressed. In addition, even if the magnetic particles escape to the intermediate chamber 178, the magnetic particles hardly reach the liquid seal member 180 according to the separation distance between the seal gap 176gs and the liquid seal member 180 sandwiching the intermediate chamber 178. Here, in particular, the communication gap 178gc forming the intermediate chamber 178 extends in accordance with the axial length of the permanent magnet 173, so that the magnetic particles need to reach the liquid seal member 180 through the intermediate chamber 178. The distance can be secured as long as possible. Moreover, even if the magnetic particles escape to the intermediate chamber 178, the magnetic particles are captured by the trap gap 178gt formed by the sleeve magnetic flux guide 175 in the intermediate chamber 178 to guide the magnetic flux MF. According to such a trapping function, the magnetic particles are prevented from reaching the liquid seal member 180 through the intermediate chamber 178 including the trap gap 178gt. For these reasons, even if the surface pressure (that is, the tightening force of the oil seal) is reduced at the seal interface 184 where the liquid seal member 180 and the brake shaft 131 are in contact as shown in FIGS. It is possible to avoid a situation where the frictional resistance is increased by entering 184.

  Further, in the seal structure 160, a sleeve magnetic flux stopper 176 is adjacent to a protruding portion 174p of the sleeve magnetic flux guide 174 that protrudes to the inner peripheral side of the permanent magnet 173. A magnetic flux stopper 166 is adjacent. Accordingly, the communication gap between the elements 176 and 166 is equal to the radial thickness Tsls of the sleeve magnetic flux stopper 176 adjacent to the protrusion 174p and the radial thickness Tshs of the axial magnetic flux stopper 166 adjacent to the axial magnetic flux guide 164. The radial width Wgc of 178 gc can be reduced. In the intermediate chamber 178 including the communication gap 178gc in which the radial width Wgc can be reduced in this way, Taylor vortex flow or turbulent flow is reduced. Here, particularly in this embodiment, the radial width Wgc of the communication gap 178gc can be reduced in a long range over the entire axial direction of the permanent magnet 173 covering from the inner peripheral side. Has a high ability to reduce turbulence. Therefore, generation | occurrence | production of the shear force which peels off a magnetic particle from the sealing film formed with the magnetorheological fluid 140 in the seal gap 176gs between the magnetic flux guides 174 and 164 is suppressed. In addition, the magnetic flux stoppers 176 and 166 can regulate the passage of the magnetic flux MF from the adjacent magnetic flux guides 174 and 164 to the intermediate chamber 178, so that the magnetic particles are transferred to the communication gap 178gc near the seal gap 176gs by the magnetic flux MF. It is suppressed that it is drawn. According to these, even when the magnetic particles escape to the intermediate chamber 178 and cause the alteration of the magnetorheological fluid 140, the magnetic particles that have escaped to the intermediate chamber 178 reach the liquid seal member 180 and cause friction at the seal interface 184. The situation of increasing resistance can also be avoided.

  In addition, in the seal structure 160, both the sleeve magnetic flux guide 175 and the sleeve extra stopper 177 disposed between the permanent magnet 173 and the liquid seal member 180 project the projecting portions 175 p and 177 p toward the inner peripheral side from the permanent magnet 173. I am letting. Thus, the radial width Wgt of the gaps 178gt, 178ge between the protrusions 175p, 177p and the elements 165, 177 of the predetermined outer diameters φshg, φsh by the protrusion heights Hslg, Hsle of the protrusions 175p, 177p. Wge can be reduced. In the intermediate chamber 178 including the gaps 178gt and 178ge in which the radial widths Wgt and Wge can be reduced by the elements 175 and 177 in this way, combined with the reduction action of the radial width Wgc by the magnetic flux stoppers 176 and 166, Taylor vortex flow or The function of reducing turbulence is enhanced. According to this, generation of shearing force that peels off the magnetic particles from the seal film can be reliably suppressed, and alteration of the magnetorheological fluid 140 can be avoided and frictional resistance of the seal interface 184 can be avoided.

  In addition, as described above, in the seal structure 160, the radial widths Wgc, Wgt, Wge of the gaps 178gc, 178gt, 178ge forming the intermediate chamber 178 can be reduced to a width Wgs substantially equal to the seal gap 176gs. Yes. Therefore, this also enhances the function of reducing Taylor vortex flow or turbulence, so that the generation of shear force that peels off the magnetic particles from the sealing film is reliably suppressed, alteration of the magnetorheological fluid 140 is prevented, and frictional resistance is increased. Avoidance can be realized.

  In view of the above, in the valve timing adjusting device 1, the fluid brake device 100 includes the seal structure 160, thereby stabilizing the brake characteristics by avoiding alteration of the magnetorheological fluid 140 and improving durability by avoiding an increase in frictional resistance. Achievable with. Here, in particular, stabilization of the brake characteristic makes it possible to maintain the adjustment accuracy of the engine phase that depends on the characteristic. In addition, the seal gap 176gs of the seal structure 160 suppresses the removal of the base liquid in which the magnetic particles are entrained and the magnetic particles due to the Taylor vortex or turbulent flow, which is necessary for capturing the magnetic particles. It is not necessary to increase the density of the passing magnetic flux MF. Therefore, the seal film formed by the magnetorheological fluid 140 that receives the relatively low-density passing magnetic flux MF has a small frictional resistance applied to the brake shaft 131. Therefore, not only the durability is improved but also the frictional resistance is caused. Thus, it is possible to avoid torcross that causes a reduction in fuel consumption of the internal combustion engine.

(Second embodiment)
As shown in FIGS. 9 and 10, the second embodiment of the present invention is a modification of the first embodiment. The axial magnetic flux stopper 2166 of the second embodiment covers a part of the outer peripheral portion 133o of the shaft main body 133 in the axial direction from the outer peripheral side. Here, a part in the axial direction covered with the axial magnetic flux stopper 2166 in the outer peripheral portion 133o shown in FIG. 10 is an end portion 2133o1 of the axial magnetic flux guide 164 connected to the outside of the housing, and the inside of the axial magnetic flux guide 165 inside the housing. This is a portion that does not reach the end 2133o2 connected to the side. Thus, the axial magnetic flux stopper 2166 is adjacent to the outside of the housing of the axial magnetic flux guide 164 but is separated from the axial magnetic flux guide 165 to the inside of the housing.

  9 and 10, the sleeve magnetic flux stopper 2176 of the second embodiment covers a part of the inner peripheral portion 173i of the permanent magnet 173 in the axial direction from the inner peripheral side. Here, a part in the axial direction covered with the sleeve magnetic flux stopper 2176 in the inner peripheral portion 173i shown in FIG. 10 is the housing of the sleeve magnetic flux guide 175 from the end portion 2173i1 adjacent to the outside of the housing of the sleeve magnetic flux guide 174. It is a portion that does not reach the end 2173i2 adjacent to the inside of the body. As a result, the sleeve magnetic flux stopper 2176 is adjacent to the outside of the housing of the sleeve magnetic flux guide 174, but is spaced from the sleeve magnetic flux guide 175 to the inside of the housing in the radial width between the sleeve magnetic flux stopper 2176 and the axial magnetic flux stopper 2166. A communication gap 2178 gc of Wgc is formed. At the same time, on the side of the magnetic flux guides 175 and 165 with respect to the magnetic flux stoppers 2176 and 2166, the gap between the inner peripheral portion 173 i of the permanent magnet 173 and the outer peripheral portion 133 o of the shaft body 133 is larger than the radial width Wgs of the seal gap 176 gs. A volume gap 2178gv1 having a large radial width Wgv1 is formed.

  Further, as shown in FIGS. 9 and 10, the extra stoppers 167 and 177 are not provided in the second embodiment. Thus, a volume gap 2178gv2 having a radial width Wgv2 larger than the radial width Wgs of the seal gap 176gs as shown in FIG. 10 is formed between the annular wall portion 172r of the magnetic shield 172 and the outer peripheral portion 133o of the shaft body 133. It is formed.

  In the second embodiment as well, as shown in FIG. 8, the nonpolar liquid and the polar liquid similar to those in the first embodiment are used as the base liquid and the intermediate fluid 190 of the magnetorheological fluid 140, respectively.

  As described above, the intermediate chamber 2178 of the second embodiment is formed by combining the gaps 2178 gc and 178 gt of the widths Wgc and Wgt substantially equal to the radial width Wgs of the seal gap 176 gs with the gaps 2178 gv 1 and 2178 gv 2 of the larger widths Wgv 1 and Wgv 2. ing. In the second embodiment, the radial width of the intermediate chamber 2178 is increased by the magnetic flux stoppers 2166 and 2176 that cover the portions of the elements 133 and 173 including the adjacent ends 2133o1 and 1173i1 of the magnetic flux guides 164 and 174. The reduced portion is limited to the communication gap 2178gc. Here, since the communication gap 2178gc is provided in the vicinity of the seal gap 176gs, which is a destination of the magnetic particles drawn by Taylor vortex or turbulent flow, the reduced portion of the intermediate chamber 2178 in the radial width is in the vicinity. It is limited. According to this, formation of magnetic flux stoppers 2166 and 2176 added for the reduction function while obtaining the Taylor vortex flow or turbulence reduction function as much as necessary for stabilizing the brake characteristics and improving the durability. The material can be reduced.

(Third embodiment)
The third embodiment of the present invention is a modification of the first embodiment. In the third embodiment, as the non-magnetic base liquid of the magnetorheological fluid 140, as shown in FIG. 8, for example, a liquid based on polyethylene glycol monoether or 1-octyl-3-methylimidazolium which is an ionic liquid Polar liquids (hydrophilic liquids) such as bis (trifluoromethylsulfonyl) amide and water are used. On the other hand, the non-magnetic intermediate fluid 190 of the third embodiment uses a nonpolar liquid (hydrophobic liquid) such as an oil of the same type or a different type from the lubricating oil of the internal combustion engine.

  In such a seal structure 160 of the third embodiment, the base liquid that is a different polar liquid with respect to the intermediate fluid 190 that is a nonpolar liquid is repelled by repulsive force, thereby causing the gap to escape from the seal gap 176gs. Mixing into the intermediate fluid 190 is suppressed. In addition, the non-magnetic and non-polar intermediate fluid 190 is mixed with the base liquid by being magnetically attracted from the intermediate chamber 178 to the seal gap 176gs together with the repulsive action with the polar base liquid. Is suppressed. Therefore, as in the first embodiment, it is possible to avoid the alteration of the magnetorheological fluid 140 and achieve stabilization of the brake characteristics.

  Further, in the seal structure 160 of the third embodiment, the magnetic particles to which the polar base liquid adheres in the magnetorheological fluid 140 repels against the nonpolar intermediate fluid 190, so that it escapes to the intermediate chamber 178 and the liquid seal. Reaching the member 180 is suppressed. Therefore, as in the first embodiment, it is possible to contribute to the improvement of durability by reducing the surface pressure at the seal interface 184 of the liquid seal member 180 and the brake shaft 131.

(Fourth embodiment)
The fourth embodiment of the present invention is a modification of the first embodiment. In the fourth embodiment, as the nonmagnetic base liquid of the magnetorheological fluid 140, as shown in FIG. 8, a nonpolar liquid such as oil similar to that in the first embodiment is used. In addition, in the fourth embodiment, as the nonmagnetic intermediate fluid 190, the same liquid as the base liquid of the magnetorheological fluid 140, that is, a nonpolar liquid such as oil is used.

  In such a seal structure 160 of the fourth embodiment, since the same intermediate fluid 190 as the base liquid of the magnetorheological fluid 140 is used, an increase in cost due to the adoption of the fluid 190 can be reduced. In addition, the non-magnetic intermediate fluid 190 is not only suppressed from being magnetically attracted from the intermediate chamber 178 to the seal gap 176gs and mixed with the base liquid, but even if it is temporarily mixed with the base liquid as the same liquid. There is no. Therefore, according to the first embodiment, it is possible to avoid the alteration of the magnetorheological fluid 140 and achieve stabilization of the brake characteristics.

(Other embodiments)
Although a plurality of embodiments of the present invention have been described above, the present invention is not construed as being limited to these embodiments, and various embodiments and combinations can be made without departing from the scope of the present invention. Can be applied.

  Specifically, in the first to fourth embodiments, as shown in FIG. 11 as a modification (the modification is a modification of the first embodiment), the outer diameter φshs of the axial magnetic flux stopper 166 is increased and the sleeve magnetic flux stopper 176 is expanded. The radial width Wgc of the communication gap 178gc may be set to be narrower than the radial width Wgs of the seal gap 176gs by at least one of the reduction of the inner diameter φsls (in the figure, a modification example in which only the reduction of the inner diameter φsls is performed). . Alternatively, as shown in FIG. 12 as a modification (the figure is a modification of the first embodiment), at least one of the reduction of the outer diameter φshs of the axial magnetic flux stopper 166 and the increase of the inner diameter φsls of the sleeve magnetic flux stopper 176 ( In the drawing, the radial width Wgc of the communication gap 178gc is larger than the radial width Wgs of the seal gap 176gs within a range in which the function of reducing the Taylor vortex flow or turbulent flow can be obtained by a modification example in which the inner diameter φsls is only enlarged. It may be set widely.

  In the first to fourth embodiments, the components 164, 166, 165, and 167 of the magnetic seal shaft 162 are not provided, as shown in FIG. 13 as a modified example (the figure is a modified example of the first embodiment). Further, the seal gap 176gs and the intermediate chambers 178 and 2178 may be formed between the components 174, 176, 175, and 177 of the magnetic seal sleeve 170 and the shaft main body 133 of the brake shaft 131. Furthermore, in 1st-4th embodiment, it is good also as a structure which does not provide the magnetic flux guides 165,175 of a housing | casing outside so that a modification (the figure is a modification of 1st embodiment) is shown in FIG. Further, in the first, third and fourth embodiments, as shown in FIGS. 14 and 15, which are modified examples (the modified example of the first embodiment), the extra stoppers 167 and 177 are similar to the second embodiment. The volume gap 2178gv2 having the radial width Wgv2 larger than the radial width Wgs of the seal gap 176gs may be formed.

  In addition, as the intermediate fluid 190 of the first and second embodiments, a non-polar liquid such as a non-polar base liquid may be used as long as it is a non-magnetic liquid that is different from the base liquid of the magnetorheological fluid 140. May use silicon oil which is difficult to dissolve. In addition, as the base liquid of the magnetorheological fluid 140 of the third embodiment, a non-polar liquid other than the intermediate fluid 190, such as silicon oil, may be used as long as it is a non-magnetic liquid. Good. In addition, if the base liquid and the intermediate fluid 190 of the magnetorheological fluid 140 of the fourth embodiment are the same liquid, the intermediate fluid 190 of the first and second embodiments can be used instead of the nonpolar liquid. A polar liquid similar to the base liquid of the magnetorheological fluid 140 of the third embodiment may be used. In addition, the fluids 140 and 190 described in the third or fourth embodiment may be used in a configuration according to the second embodiment.

  In addition to the device that adjusts the valve timing of the intake valve as the “valve”, the present invention also includes a device that adjusts the valve timing of the exhaust valve as the “valve” and both the intake valve and the exhaust valve. In addition to a device that adjusts the valve timing, it can be applied to various devices that use brake torque.

1 valve timing adjusting device, 2 cam shaft, 100 fluid brake device, 110 housing, 111 fixing member, 112 cover member, 130 brake rotating body, 131 brake shaft, 133 shaft main body, 133o outer peripheral portion, 150 solenoid coil (viscosity control Means), 160 seal structure, 162 magnetic seal shaft, 164 axis magnetic flux guide (axial magnetic flux guide with an axial magnetic flux stopper adjacent to the outside of the housing), 165 axial magnetic flux guide, 166, 2166 axial magnetic flux stopper, 167 axial extra stopper, 170 Magnetic seal sleeve, 173 Permanent magnet, 173i Inner circumference, 174 Sleeve flux guide (flux guide / sleeve flux guide with permanent magnet adjacent to the outside of the housing), 175 Sleeve flux guide (outer member), 174p, 175p, 177p protrusion, 176 , 2176 Sleeve magnetic flux stopper (magnetic flux stopper), 176gs Seal gap, 177 Sleeve extra stopper (outer peripheral member), 178, 2178 Intermediate chamber, 178gc, 2178gc Communication gap, 178ge Extra gap, 178gt Trap gap, 180 Liquid seal member, 182 Seal Lip, 184 seal interface, 190 intermediate fluid, 200 energization control circuit (viscosity control means), 300 phase adjustment mechanism, 2133o1, 1233o2, 2173i1, 2173i2 end, 2178gv1, 2178gv2 volume gap, MF magnetic flux, N, S magnetic pole, Wgc , Wge, Wgs, Wgt, Wgv1, Wgv2 radial width, φsle, φslg, φsls

Claims (10)

A housing that forms a fluid chamber therein;
A magnetorheological fluid in which magnetic particles are dispersed in a non-magnetic base liquid, enclosed in the fluid chamber, and the viscosity changes according to the passing magnetic flux;
Viscosity control means for variably controlling the viscosity of the magnetorheological fluid by passing magnetic flux through the magnetorheological fluid in the fluid chamber;
A brake rotor that has a brake shaft that penetrates the housing in and out in the axial direction, and that receives a brake torque according to the viscosity of the magnetorheological fluid by contacting the magnetorheological fluid in the fluid chamber; ,
A fluid brake device comprising: a seal structure that seals between the housing and the brake shaft;
The seal structure is
A magnetic flux guide that surrounds the outer periphery of the brake shaft in the housing, forms a seal gap communicating with the fluid chamber, and the brake shaft, and guides the magnetic flux to the brake shaft through the seal gap;
A permanent magnet that surrounds the outer peripheral side of the brake shaft adjacent to the outside of the housing of the magnetic flux guide in the housing and generates magnetic flux guided from the magnetic flux guide to the brake shaft by magnetic poles;
A liquid seal member that is disposed on the outer side of the casing with respect to the permanent magnet in the casing, contacts the brake shaft from the outer peripheral side, and seals between the brake shaft in a liquid-tight manner;
An intermediate fluid filling the intermediate chamber sandwiched between the seal gap and the liquid seal member as a non-magnetic liquid;
In the case, the outer peripheral side of the brake shaft is formed adjacent to the outer side of the case adjacent to the outer side of the protrusion of the magnetic flux guide that protrudes inward from the permanent magnet. And a magnetic flux stopper for restricting the passage of magnetic flux to the intermediate chamber.   The seal structure is disposed between the permanent magnet and the liquid seal member in the housing, surrounds the outer peripheral side of the brake shaft, and protrudes to the inner peripheral side from the permanent magnet. The fluid brake device according to claim 1, further comprising an outer peripheral member that forms the intermediate chamber therebetween.   The said magnetic flux stopper forms the said intermediate chamber of the radial direction width equal to the said seal gap by having radial direction thickness equal to the protrusion height of the said protrusion part of the said magnetic flux guide. 2. The fluid brake device according to 2.   The fluid brake device according to any one of claims 1 to 3, wherein the magnetic flux stopper covers the entire area of the permanent magnet in the axial direction from the inner peripheral side.   The said magnetic flux stopper covers a part of axial direction including the adjacent edge part with the said magnetic flux guide among the said permanent magnet from the inner peripheral side, The Claim 1 characterized by the above-mentioned. Fluid brake device. The seal structure is
An axial magnetic flux guide that forms the seal gap with the sleeve magnetic flux guide by projecting to the outer peripheral side toward the sleeve magnetic flux guide as the magnetic flux guide in the brake shaft;
In the brake shaft, adjacent to the outside of the housing of the shaft magnetic flux guide, is arranged on the inner peripheral side of a sleeve magnetic flux stopper as the magnetic flux stopper, and is connected to the intermediate chamber formed between the sleeve magnetic flux stopper. The fluid brake device according to any one of claims 1 to 5, further comprising an axial magnetic flux stopper that restricts passage of magnetic flux.   The fluid brake device according to any one of claims 1 to 6, wherein the intermediate fluid is a liquid different from the base liquid. The base liquid is one of a polar liquid and a nonpolar liquid,
The fluid brake device according to claim 7, wherein the intermediate fluid is the other of the polar liquid and the nonpolar liquid.   The fluid brake device according to claim 1, wherein the intermediate fluid is the same liquid as the base liquid. A valve timing adjusting device for adjusting a valve timing of a valve that opens and closes a camshaft by torque transmission from a crankshaft in an internal combustion engine,
The fluid brake device according to any one of claims 1 to 9,
The relative phase between the crankshaft and the camshaft is linked to the brake shaft outside the housing of the fluid brake device, and the crankshaft and the camshaft are adjusted according to the brake torque input to the brake rotating body of the fluid brake device. A valve timing adjusting device comprising: a phase adjusting mechanism that performs the same.

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