JP2013127238A - Hydraulic braking device and valve timing adjusting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic braking device that avoids a change in braking characteristics.SOLUTION: A magnetic seal sleeve 162 held in a casing 110 forming a fluid chamber 114 includes: a magnetic flux guide 164 that has an inner periphery 164a that forms a seal gap 185 with a brake shaft 131 therebetween and guides a magnetic flux from the inner periphery 164a to the brake shaft 131 through a seal gap 184; and a magnetic flux stopper 166 that restricts the flow of the magnetic flux from the inner periphery 164a to the casing inner side by shielding the inner periphery 164a of the magnetic flux guide 164 from the casing inner side and forms a communication gap 186 with the brake shaft 131 therebetween, which communicates the fluid chamber 114 with the seal gap 184. The magnetic flux stopper 166 gives the communication gap 186 with a width not larger than that of the seal gap 184 at all over the range between the fluid chamber 114 and the seal gap 184 in the longitudinal section along the axial direction of 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, there has been known a fluid brake device that variably controls the viscosity of the magnetorheological fluid that comes into contact with the brake rotating body by passing a magnetic flux through a fluid chamber in which the magnetorheological fluid is sealed. 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 kind of fluid brake device, Patent Document 1 discloses a device that seals between a case and a brake shaft that penetrates the case in and out of the brake rotating body in the axial direction with a magnetorheological fluid. Has been. Specifically, in the fluid brake device of Patent Document 1, a permanent magnet and a magnetic flux guide that constitute a seal structure are held in a casing so as to surround the outer peripheral side of the brake shaft. With this holding form, 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 that has flowed into the seal gap through which the magnetic flux passes from the fluid chamber is trapped in a film shape 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 fluctuations in the brake characteristics due to leakage of the magnetorheological fluid from the fluid chamber.

JP 2010-121614 A

  However, as a result of intensive studies by the 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 cause is that when magnetic particles dispersed in the base liquid as a constituent component of the magnetorheological fluid are concentrated inside the casing of the magnetic flux guide, the magnetic particles in the magnetorheological fluid trapped in the seal gap are collected. It is pushed out by the influence of particles and leaks to the outside of the housing.

  Specifically, in the case of the fluid brake device of Patent Document 1, among the magnetic flux guides covered from the inside of the housing by the nonmagnetic shield that restricts the passage of magnetic flux, the axial end surface of the inner peripheral portion that forms the seal gap is The fluid chamber is exposed through the inner peripheral side of the nonmagnetic shield. When magnetic particles in the magnetorheological fluid are gathered from the fluid chamber inside the casing in the vicinity of the seal gap due to the leakage magnetic flux from the exposed inner periphery of the magnetic flux guide, magnetic attraction is performed so as to draw the gathered particles into the seal gap. Force is generated. As a result, when the total magnetic attractive force acting on each aggregated particle becomes larger than the total friction force acting between the magnetic flux guide and the magnetic particles or between the magnetic particles in the seal gap, the seal gap into which the aggregated particles are drawn. The magnetic particles that have been trapped in are pushed out of the housing and leak out. Here, leakage of magnetic particles from the seal gap is undesirable because it reduces the self-sealing function and causes fluctuations in brake characteristics.

  The present invention has been made in view of the above-described problems, and the object thereof is to provide a fluid brake device that achieves avoidance of fluctuations in brake characteristics, and a valve timing adjusting device including the fluid brake device. There is to do.

The invention according to claim 1 is a magnetorheological fluid in which a magnetic chamber is formed inside, a magnetic particle dispersed in a base liquid, enclosed in the fluid chamber, and the viscosity changes in accordance with the passing magnetic flux. And a viscosity control means for variably controlling the viscosity of the magnetorheological fluid by allowing magnetic flux to pass through the fluid chamber, and a brake shaft that penetrates the housing in and out in the axial direction, and is in contact with the magnetorheological fluid in the fluid chamber A brake rotating body to which a brake torque according to the viscosity of the magnetorheological fluid is input, and a magnetic seal sleeve that is held by the housing and surrounds the outer periphery of the brake shaft and generates a magnetic flux that guides the brake shaft. A fluid brake device comprising:
The magnetic seal sleeve has an inner peripheral part that forms a seal gap with the brake shaft, a magnetic flux guide that guides the magnetic flux from the inner peripheral part to the brake shaft through the seal gap, and an inner peripheral part of the magnetic flux guide. A magnetic flux stopper that restricts the passage of magnetic flux from the inner periphery to the inside of the housing by covering from the inside of the body, and forms a communication gap between the fluid chamber and the seal gap between the brake shaft and And a magnetic flux stopper that gives the communication gap a width equal to or smaller than the seal gap in a longitudinal section along the axial direction of the brake shaft.

  According to the first aspect of the present invention, the seal gap formed between the inner periphery of the magnetic flux guide of the magnetic seal sleeve and the brake shaft and communicating with the fluid chamber via the communication gap is enclosed in the fluid chamber. Of a magnetorheological fluid. Therefore, the magnetic particles in the magnetorheological fluid filling the seal gap are trapped by the action of the magnetic flux guided from the magnetic flux guide to the brake shaft through the seal gap, thereby forming a seal film. The seal film thus formed in the seal gap can exhibit a self-seal function so that 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. is there.

  Further, in the first aspect of the invention, the inner periphery of the magnetic flux guide in the magnetic seal sleeve is covered from the inside of the housing by the magnetic flux stopper, so that the passage of magnetic flux from the inner periphery to the inside of the housing is restricted. Will be. As a result, magnetic flux leakage from the inner peripheral portion of the magnetic flux guide forming the seal gap to the communication gap formed between the magnetic flux stopper and the brake shaft is reduced, so that the magnetic particles in the magnetorheological fluid are removed from the communication gap. Concentration in the vicinity of the seal gap can be suppressed. In addition, in the communication gap that is given a width that is equal to or smaller than the seal gap in the longitudinal section along the axial direction of the brake shaft, the pressure loss when the magnetic particles flow increases more than the seal gap. Thereby, it can also suppress that the magnetic particle of a fluid chamber reaches | attains a magnetic flux guide inner peripheral part through a communicating gap.

  Therefore, according to these concentration restraining and arrival restraining actions, the total magnetic attraction force that draws each magnetic particle inside the housing into the seal gap is between the magnetic flux guide and the magnetic particles or between the magnetic particles at the seal gap. It can be kept smaller than the working frictional force. This makes it difficult for the magnetic particles to leak to the outside of the housing due to the pulling of the magnetic particles in the seal gap, so that the self-sealing function of the sealing film formed by capturing the magnetic particles is maintained and the brake is applied. It is possible to avoid fluctuations in characteristics.

  According to the second aspect of the present invention, the magnetic flux stopper has an inner peripheral portion that is formed with an inner diameter equal to or smaller than the magnetic flux guide and sandwiches the communication gap with the brake shaft. Since the inner peripheral portion of the magnetic flux stopper according to the present invention is formed to have a relatively small inner diameter that is smaller than the magnetic flux guide, the brake shaft on which the magnetic particles flowing into the communication gap between the inner peripheral portion of the magnetic flux stopper and the brake shaft rotate. The sliding resistance given to can be kept small. Therefore, it is possible to avoid fluctuations in the brake characteristics due to the sliding resistance generated between the particles flowing into the communication gap and the brake shaft.

  According to a third aspect of the present invention, the magnetic flux stopper has an inner peripheral portion which is formed to have the same inner diameter as the magnetic flux guide and which gives the communication gap the same width as the seal gap in the longitudinal section. In this invention, the inner periphery of the magnetic flux stopper having the same inner diameter as that of the magnetic flux guide forms a communication gap having the same width as the seal gap in the longitudinal section, so that the sliding generated between the magnetic particles flowing into the gap and the brake shaft. Any dynamic resistance can be suppressed to an appropriate size. Therefore, it is possible to avoid the brake characteristics from fluctuating due to the sliding resistance generated between the particles flowing into the communication gap and the seal gap and the brake shaft.

  According to the fourth aspect of the present invention, the communication gap is formed across both end faces of the magnetic flux stopper that is thicker than the magnetic flux guide in the axial direction. Since the communication gap of the present invention can be formed as long as possible across both axial end faces of the magnetic flux stopper that is thicker in the axial direction than the magnetic flux guide, it is possible to increase the pressure loss when the magnetic particles flow. Therefore, it is possible to enhance the effect of suppressing the arrival of the magnetic particles to the inner periphery of the magnetic flux guide, and thus the effect of avoiding fluctuations in brake characteristics.

  According to the invention described in claim 5, the magnetic flux stopper forms a labyrinth-like communication gap that meanders between the fluid chamber and the seal gap. Since the communication gap of the present invention is as long as possible between the fluid chamber and the seal gap due to the labyrinth meandering form, the pressure loss during the flow of the magnetic particles can be increased. Therefore, it is possible to enhance the effect of suppressing the arrival of the magnetic particles to the inner periphery of the magnetic flux guide, and thus the effect of avoiding fluctuations in brake characteristics.

  According to the sixth aspect of the present invention, the magnetic flux stopper covers the entire axial end surface of the magnetic flux guide from the inside of the housing. In the magnetic flux guide of the present invention, the axial end surface is covered not only in the inner peripheral portion forming the seal gap but also on the outer peripheral side thereof with the magnetic flux stopper on the inner side of the housing. It is possible to suppress the magnetic particles from being adsorbed to the magnetic flux and changing the magnetic flux passing through the seal gap. As a result, the self-sealing function of the seal film formed according to the magnetic flux passing through the seal gap can be stably exhibited, and the effect of avoiding fluctuations in brake characteristics can be enhanced.

  According to the invention described in claim 7, the brake shaft has an outer peripheral portion that projects toward the inner peripheral portion of the sleeve magnetic flux guide as the magnetic flux guide to form a seal gap with the inner peripheral portion. An axial magnetic flux guide that guides the magnetic flux to the outer peripheral portion through a seal gap, and covering the outer peripheral portion of the axial magnetic flux guide from the inner side of the housing, thereby restricting the passage of magnetic flux from the outer peripheral portion to the inner side of the housing. And an axial magnetic flux stopper that forms a communication gap with the sleeve magnetic flux stopper as the magnetic flux stopper.

  In the invention according to claim 7, the seal gap formed between the outer periphery of the shaft magnetic flux guide protruding toward the inner periphery of the sleeve magnetic flux guide and the inner periphery of the brake shaft includes: The magnetorheological fluid sealed in the fluid chamber flows from the communication gap. As a result, the magnetic particles in the magnetorheological fluid flowing into the seal gap are captured by the action of the magnetic flux guided from the inner periphery of the sleeve magnetic flux guide to the outer periphery of the axial magnetic flux guide through the seal gap, so that the self-sealing function Is formed in the seal gap. Here, since the density of the passing magnetic flux is high in the seal gap formed by the protruding axial magnetic flux guide close to the sleeve magnetic flux guide, a seal film having high pressure resistance can be formed.

  Furthermore, in the invention according to claim 7, since the inner periphery of the sleeve magnetic flux guide is covered from the inside of the housing by the sleeve magnetic flux stopper in the magnetic seal sleeve, the passage of magnetic flux from the inner peripheral portion to the inside of the housing is prevented. It will be regulated. Similarly, since the outer periphery of the axial magnetic flux guide is covered from the inner side of the housing by the axial magnetic flux stopper in the brake shaft, the passage of magnetic flux from the inner peripheral portion to the inner side of the housing is restricted. As a result of such restrictions, magnetic flux leakage from the inner peripheral portion of the sleeve magnetic flux guide and the outer peripheral portion of the axial magnetic flux guide forming the seal gap to the communication gap between the magnetic flux stoppers is reduced, so that the magnetic particles in the magnetorheological fluid communicate with each other. Concentration in the vicinity of the seal gap from the gap can be suppressed.

  According to such a concentration suppressing action, a magnetic attraction force that draws magnetic particles inside the housing into the seal gap even under a configuration in which a seal gap having a high passing magnetic flux density is formed by the protruding form of the axial magnetic flux guide. Can be kept small. Therefore, the self-sealing function by the high pressure-resistant sealing film can be maintained, and the effect of avoiding fluctuations in brake characteristics can be enhanced.

  According to the eighth aspect of the present invention, the magnetic seal sleeve further includes a permanent magnet that generates a magnetic flux guided by the magnetic pole from the inner peripheral portion of the magnetic flux guide inside the housing, and the magnetic flux stopper is the permanent magnet. The inner periphery of the magnetic flux guide that guides the generated magnetic flux is covered from the inside of the housing. In the present invention, the magnetic flux generated by the magnetic poles of the permanent magnet is allowed to pass from the inner peripheral part of the magnetic flux guide on the inner side of the casing to the seal gap side as a guide destination, while from the inner peripheral part of the magnetic flux guide to the casing. The passage to the inner side is restricted by the magnetic flux stopper. According to this, the self-sealing function of the sealing film formed according to the magnetic flux passing through the seal gap is maintained by the action of suppressing the arrival of the magnetic particles with respect to the inner peripheral portion of the magnetic flux guide, thereby enhancing the effect of avoiding fluctuations in brake characteristics. Is possible.

  According to the ninth aspect of the present invention, the magnetic flux guide is disposed on the inner side of the casing of the permanent magnet, and the magnetic flux stopper is exposed to the fluid chamber on the inner side of the casing, so that the gap between the fluid chamber and the seal gap is increased. Give the communication gap a width less than the seal gap throughout the entire area. In this invention, since the inner peripheral part of the magnetic flux guide arranged on the inner side of the casing of the permanent magnet is covered from the inner side of the casing by the magnetic flux stopper, the generated magnetic flux of the permanent magnet passes from the inner peripheral part to the inner side of the casing. To be regulated. As a result, the magnetic flux leaks from the inner peripheral portion of the magnetic flux guide forming the seal gap to the communication gap formed between the magnetic flux stopper and the brake shaft on the inner side of the casing that is exposed to the fluid chamber of the magnetic flux stopper. But less. Therefore, it is possible to suppress the magnetic particles in the magnetorheological fluid sealed in the fluid chamber from being collected from the communication gap in the vicinity of the seal gap, and to prevent leakage of the magnetic particles from both the fluid chamber and the seal gap. Moreover, in the communication gap that gives a width equal to or smaller than the seal gap in the longitudinal section in the entire region between the fluid chamber and the seal gap, the pressure loss more than the seal gap when the magnetic particles flow can be reliably obtained, so that the magnetic particles communicate with each other. Reaching the inner periphery of the magnetic flux guide through the gap can also be suppressed. According to the above, it is possible to enhance the effect of avoiding fluctuations in brake characteristics.

  According to the tenth aspect of the present invention, the magnetic flux guide is disposed on the outer side of the casing of the permanent magnet, has an inner peripheral portion that protrudes toward the inner peripheral side of the permanent magnet, and the magnetic flux stopper is an inner portion of the permanent magnet. It arrange | positions at the periphery side and covers the inner peripheral part of a magnetic flux guide from the housing | casing internal side. In this invention, in the magnetic flux guide arranged on the outer side of the casing of the permanent magnet, the inner peripheral portion that protrudes to the inner peripheral side of the permanent magnet is covered from the inner side of the casing by the magnetic flux stopper. Is restricted from passing to the inside of the housing from the inner periphery. As a result, less magnetic flux leaks from the inner periphery of the magnetic flux guide forming the seal gap to the communication gap formed between the magnetic flux stopper and the brake shaft on the inner side of the casing, which is the inner peripheral side of the permanent magnet. Become. Therefore, it is possible to prevent the magnetic particles in the magnetorheological fluid from concentrating from the communication gap to the vicinity of the seal gap, and to prevent the leakage of the magnetic particles from the seal gap, so that it is possible to avoid fluctuations in brake characteristics.

  According to the eleventh aspect of the present invention, the pair of magnetic flux guides arranged on the outer side and the inner side of the permanent magnet have inner peripheral portions that protrude toward the inner peripheral side of the permanent magnet. The magnetic flux stopper is disposed on the inner peripheral side of the permanent magnet, covers the inner peripheral part of the magnetic flux guide on the outer side of the casing from the inner side of the casing, and covers the inner peripheral part of the magnetic flux guide on the inner side of the casing. Cover from the side. According to the present invention, in the pair of magnetic flux guides arranged on the outer side of the casing and the inner side of the permanent magnet, the inner peripheral portions protruding to the inner peripheral side from the permanent magnet are respectively the outer side of the casing and the inner side of the casing. By being covered with a magnetic flux stopper from the side, the magnetic flux generated by the permanent magnet is restricted from being short-circuited through the magnetic particles between the inner peripheral portions. As a result, magnetic flux leakage in the axial direction is suppressed between the magnetic flux guides that respectively form the seal gap, and the concentration of magnetic particles in the vicinity of the seal gap is also suppressed as described above. Leakage of magnetic particles is less likely to occur. Therefore, it is possible to enhance the effect of avoiding fluctuations in brake characteristics.

  According to a twelfth aspect of the present invention, the brake shaft protrudes toward the inner peripheral portion of the sleeve magnetic flux guide as each of the magnetic flux guides, thereby forming an outer peripheral portion that forms a seal gap with the inner peripheral portion. A pair of axial magnetic flux guides that guide the magnetic flux through the seal gap to the outer periphery thereof, and an axial magnetic flux guide on the outside of the housing from the inside of the housing, and an axial magnetic flux guide on the inside of the housing. Covering from the outside of the body has an axial magnetic flux stopper that restricts the passage of magnetic flux from these axial magnetic flux guides and forms a communication gap between the magnetic flux stopper and the sleeve magnetic flux stopper.

  In the invention described in claim 12, the seal formed between the outer peripheral portion of each axial magnetic flux guide protruding toward the inner peripheral portion of each sleeve magnetic flux guide and the inner peripheral portion of the brake shaft. The magnetorheological fluid sealed in the fluid chamber flows into the gap from the communication gap. As a result, the magnetic particles in the magnetorheological fluid flowing into the seal gap are captured under the action of the magnetic flux guided from the inner peripheral portion of each sleeve magnetic flux guide to the outer peripheral portion of each axial magnetic flux guide through the seal gap. A seal film that exhibits a self-sealing function is formed in the seal gap. Here, since the density of the passing magnetic flux is increased in the seal gap formed by the protruding axial magnetic flux guides close to the sleeve magnetic flux guides, a high pressure-resistant seal film can be formed.

  Furthermore, in the invention according to claim 12, since the inner peripheral portion of the sleeve magnetic flux guide on the outer side of the casing is covered from the inner side of the casing by the sleeve magnetic flux stopper in the magnetic seal sleeve, The passage of magnetic flux to is restricted. Similarly, since the axial magnetic flux guide on the outside of the housing is covered from the inside of the housing by the axial magnetic flux stopper in the brake shaft, the passage of magnetic flux from the axial magnetic flux guide to the inside of the housing is restricted. . As a result of such regulation, the magnetic flux leaking from the sleeve magnetic flux guide inner peripheral portion and the axial magnetic flux guide outer peripheral portion forming the seal gap to the communication gap between the magnetic flux stoppers on the inner peripheral side of the permanent magnet is reduced. Therefore, it can suppress that the magnetic particle in a magnetorheological fluid gathers in the seal gap vicinity from a communicating gap.

  According to such a concentration suppressing action, even if the seal gap having a high passing magnetic flux density is formed by the protruding form of the axial magnetic flux guide, the magnet is magnetized from the inside of the casing, which is the inner peripheral side of the permanent magnet, to the seal gap. Magnetic attraction force that attracts particles can be kept small. Therefore, the self-sealing function by the high pressure-resistant sealing film can be maintained, and the effect of avoiding fluctuations in brake characteristics can be enhanced.

  In addition, in the invention according to claim 12, the inner peripheral portion of each sleeve magnetic flux guide that protrudes to the inner peripheral side from the permanent magnet is covered with the sleeve magnetic flux stopper from the outer side and the inner side of the case, respectively. Thus, the short circuit through the magnetic particles of the magnetic flux generated by the permanent magnet is regulated between the inner peripheral portions. Similarly, the magnetic flux guide particles are guided from the magnetic seal sleeve between the axial magnetic flux guides by covering each axial magnetic flux guide with the axial magnetic flux stopper from the outside and inside of the housing. Short circuit through is regulated. As a result, the magnetic flux leakage in the axial direction is suppressed both between the sleeve magnetic flux guide and between the axial magnetic flux guides, and the concentration of magnetic particles in the vicinity of the seal gap is also suppressed as described above. Leakage of magnetic particles from the gap is less likely to occur. Therefore, it is possible to enhance the effect of avoiding fluctuations in brake characteristics.

  According to the invention of claim 13, the brake shaft protrudes toward the inner peripheral portion of each sleeve magnetic flux guide as each of the magnetic flux guides, thereby forming an outer periphery that forms a seal gap with the inner peripheral portion. And a pair of axial magnetic flux guides in which the magnetic flux is guided through a seal gap on the outer periphery thereof, and the sleeve magnetic flux stopper enters between the axial magnetic flux guides and communicates with the axial magnetic flux guides. Create a gap.

  In the invention described in claim 13, the seal formed between the outer peripheral portion of each axial magnetic flux guide protruding toward the inner peripheral portion of each sleeve magnetic flux guide and the inner peripheral portion of the brake shaft. The magnetorheological fluid sealed in the fluid chamber flows into the gap from the communication gap. As a result, the magnetic particles in the magnetorheological fluid flowing into the seal gap are captured under the action of the magnetic flux guided from the inner peripheral portion of each sleeve magnetic flux guide to the outer peripheral portion of each axial magnetic flux guide through the seal gap. A seal film that exhibits a self-sealing function is formed in the seal gap. Here, since the density of the passing magnetic flux is increased in the seal gap formed by the protruding axial magnetic flux guides close to the sleeve magnetic flux guides, a high pressure-resistant seal film can be formed.

  Furthermore, in the invention described in claim 13, the sleeve magnetic flux stopper is inserted between a pair of axial magnetic flux guides on the outer side of the casing and the inner side of the casing, so that the magnetic seal sleeve is interposed between the axial magnetic flux guides. The short circuit through the magnetic particles of the magnetic flux guided from is controlled. As a result, the leakage of the magnetic flux in the axial direction is suppressed both between the sleeve magnetic flux guide and between the axial magnetic flux guides, and the concentration of magnetic particles in the vicinity of the seal gap is also suppressed as described above. Leakage of magnetic particles from the liquid is less likely to occur. Therefore, it is possible to enhance the effect of avoiding fluctuations in brake characteristics.

  A fourteenth aspect of the invention 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. And a phase adjustment mechanism that is linked to the brake shaft outside the housing of the fluid brake device and adjusts the engine phase in accordance with the brake torque input to the brake rotating body of the fluid brake device. .

  In such an invention according to claim 14, the fluid brake device according to any one of claims 1 to 13 avoids fluctuations in brake characteristics and increases the adjustment accuracy of the engine phase affected by the brake characteristics. High accuracy can be maintained. Furthermore, according to the seal film formed of the magnetorheological fluid in the fluid brake device, the sliding resistance applied to the rotating brake shaft can be reduced, and hence the fuel consumption of the internal combustion engine is reduced due to the sliding resistance. This also makes it possible to avoid Torcross.

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 a schematic diagram for demonstrating the seal structure of FIG. It is sectional drawing which expands and shows the seal structure of the fluid brake device by 2nd embodiment of this invention. It is sectional drawing which expands and shows the seal structure of the fluid brake device by 3rd embodiment of this invention. It is sectional drawing which expands and shows the fluid brake device by 4th 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 5th embodiment of this invention. It is sectional drawing which expands and shows the seal structure of the fluid brake device by 6th embodiment of this invention. It is sectional drawing which expands and shows the seal structure of the fluid brake device by 7th embodiment of this invention. It is sectional drawing which expands and shows the seal structure of the fluid brake device by 8th embodiment of this invention. It is sectional drawing which expands and shows the seal structure of the fluid brake device by 9th 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 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 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 3rd 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 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 4th embodiment of this invention. It is sectional drawing which expands and shows the seal structure of the fluid brake device by the modification of 5th embodiment of this invention. It is sectional drawing which expands and shows the seal structure of the fluid brake device by the modification of 5th embodiment of this invention. It is sectional drawing which expands and shows the seal structure of the fluid brake device by the modification of 6th embodiment of this invention. It is sectional drawing which expands and shows the seal structure of the fluid brake device by the modification of 8th embodiment of this invention. It is sectional drawing which expands and shows the seal structure of the fluid brake device by the modification of 9th 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 of a magnetic material in a stepped cylindrical shape 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 projecting to the outside of the housing 110 becomes 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. The fluid chamber 114 has a portion sandwiched between the brake rotor 132 and the fixing member 111 in the axial direction as the first magnetic gap 114a, and a portion sandwiched between the brake rotor 132 and the cover member 112 in the axial direction is the second magnetic gap. The gap 114b is provided.

  A magnetorheological fluid 140 is sealed in advance in the fluid chamber 114 including the magnetic gaps 114a and 114b. The magnetorheological fluid 140, which is a kind of functional fluid, is obtained by dispersing powdery magnetic particles in a suspension in a non-magnetic base liquid. As the base liquid of the magnetorheological fluid 140, a liquid non-magnetic material such as oil is used, and more preferably, the same kind of oil as the lubricating oil of the internal combustion engine is used. As the magnetic particles of the magnetorheological fluid 140, a powdery magnetic material such as carbonyl iron is used. In the magnetorheological fluid 140 having such a component structure, the apparent viscosity increases as shown in FIG. 4 as the magnetic particles gather together following the density of the passing magnetic flux, and the yield stress increases in proportion to the viscosity. It has the characteristic to do.

  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. In this embodiment, when the solenoid coil 150 having such a holding configuration is energized, the magnetic flux passes through the fixing member 111, the first magnetic gap 114a, the brake rotor 132, the second magnetic gap 114b, and the cover member 112 sequentially. Occur.

  Therefore, when the solenoid coil 150 is energized and generates magnetic flux during operation of the internal combustion engine in which the brake rotator 130 rotates counterclockwise in FIGS. 2 and 3, the magnetic gaps 114 a and 114 b in the fluid chamber 114 are generated. The generated magnetic flux passes through the magnetorheological fluid 140. As a result, between the elements 110 and 130 that are in contact with the magnetorheological fluid 140 whose viscosity has changed, the brake torque that brakes the brake rotator 130 (brake rotor 132) by the action of viscous resistance is the rotation direction of the brake rotator 130. It occurs in the reverse direction (clockwise in FIGS. 2 and 3). As described above, in the present embodiment, the solenoid coil 150 that is energized passes the magnetic flux through the magnetorheological fluid 140 in the fluid chamber 114, so that a brake torque corresponding to the viscosity of the fluid 140 can be input to the brake rotor 130. It has become.

  As shown in FIG. 1, 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 axial direction, radial direction, and rotational direction common to the casing 110 and the brake shaft 131 are simply referred to as “axial direction”, “radial direction”, and “rotational direction”, respectively.

  As shown in FIG. 5, the seal structure 160 for isolating the fluid chamber 114 filled with the magnetorheological fluid 140 inside the housing from the outside of the housing is an inner peripheral portion of the fixing member 111 in the housing 110. A magnetic seal sleeve 162 held on the substrate. The magnetic seal sleeve 162 is a combination of a permanent magnet 163, sleeve magnetic flux guides 164 and 165, and a sleeve magnetic flux stopper 166, and is arranged coaxially with the brake shaft 131.

  As shown in FIGS. 5 and 6, the permanent magnet 163 is formed in an annular flat plate shape by a ferrite magnet or the like and surrounds the outer peripheral side of the brake shaft 131. The permanent magnet 163 has magnetic poles N and S having opposite polarities at both ends in the axial direction, and generates a magnetic flux MF constantly between the magnetic poles N and S.

  The pair of sleeve magnetic flux guides 164 and 165 is formed in an annular flat plate shape by a magnetic material such as carbon steel, and surrounds the outer peripheral side of the brake shaft 131 with the permanent magnet 163 sandwiched therebetween in the axial direction. The axial thickness Tslg of each of the sleeve magnetic flux guides 164 and 165 is set to be thinner than the axial thickness Tslm of the permanent magnet 163. Further, the inner diameter φslg of each of the sleeve magnetic flux guides 164 and 165 is set smaller than the inner diameter φslm of the permanent magnet 163. The sleeve magnetic flux guides 164 and 165 having these settings form inner peripheral portions 164 a and 165 a that protrude from the permanent magnet 163 toward the brake shaft 131 on the inner peripheral side.

  The sleeve magnetic flux stopper 166 is formed in a bottomed cylindrical shape by a nonmagnetic material such as austenitic stainless steel capable of restricting the passage of the magnetic flux MF, and surrounds the outer peripheral side of the brake shaft 131. The sleeve magnetic flux stopper 166 directs the opening portion of the peripheral wall portion 167 and the bottom wall portion 168 to the housing outer side and the housing inner side in the axial direction, respectively. The axial thickness Tslp of the cylindrical peripheral wall portion 167 of the sleeve magnetic flux stopper 166 is set to be thicker than the total thickness 2Tslg + Tslm of the elements 164, 163, and 165. Further, the inner diameter φslp of the peripheral wall portion 167 is set to be substantially the same as the common outer diameter φslc of the elements 164, 163, 165. With these settings, the peripheral wall portion 167 is fitted to the outer peripheral portions 164c, 163c, 165c of the elements 164, 163, 165.

  On the other hand, the axial thickness Tslb of the annular flat plate bottom wall portion 168 of the sleeve magnetic flux stopper 166 is set to be thicker than the axial thickness Tslg of the sleeve magnetic flux guide 164 on the inside of the housing with respect to the permanent magnet 163. ing. Further, the inner diameter φslb of the inner peripheral portion 168 a of the bottom wall portion 168 is set to be substantially the same as the inner diameter φslg of the sleeve magnetic flux guide 164. With these settings, the axial end surface 168b on the outside of the housing of the bottom wall 168 is in surface contact with the axial end surface 164b on the inside of the housing of the sleeve magnetic flux guide 164 in the entire radial and rotational directions. That is, the bottom wall portion 168 covers the entire end surface 164b of the sleeve magnetic flux guide 164 from the inner peripheral portion 164a to the outer peripheral portion 164c from the inside of the housing.

  In addition to the magnetic seal sleeve 162 having such a configuration, the seal structure 160 of this embodiment shown in FIG. 5 further includes axial magnetic flux guides 134 and 135 and an axial magnetic flux stopper 136 provided on the brake shaft 131.

  As shown in FIGS. 5 and 6, the pair of axial magnetic flux guides 134 and 135 are formed of a magnetic material such as carbon steel in an annular flat plate integrated with the columnar shaft main body 133 of the brake shaft 131. It is enclosed from the outer peripheral side by the sleeve magnetic flux guides 164 and 165. The axial thickness Tshg of each axial magnetic flux guide 134, 135 is set to be substantially the same as the axial thickness Tslg of each sleeve magnetic flux guide 164, 165. Further, the outer diameter φshg of each of the magnetic flux guides 134 and 135 is set smaller than the inner diameter φslg of each of the sleeve magnetic flux guides 164 and 165.

  Here, the shaft magnetic flux guide 134 on the inner side of the housing protrudes from the outer peripheral portion 133a of the shaft main body 133 toward the sleeve magnetic flux guide 164 on the inner side of the housing. With such a protruding form, the outer circumferential portion 134a of the axial magnetic flux guide 134 has a radial width Wse in a longitudinal section along the axial direction (for example, the section shown in FIGS. 5 and 6 and hereinafter also simply referred to as “longitudinal section”). An annular seal gap 184 that is substantially constant in the axial direction and the rotational direction is formed between the inner peripheral portion 164 a of the sleeve magnetic flux guide 164. Further, the axial magnetic flux guide 135 on the outer side of the casing protrudes from the outer peripheral portion 133a of the shaft main body 133 toward the sleeve magnetic flux guide 165 on the outer side of the casing. With such a protruding form, the outer peripheral portion 135a of the axial magnetic flux guide 135 has an annular seal gap 185 in which the radial width Wse in the longitudinal section is substantially constant in the axial direction and the rotational direction, and the inner peripheral portion 165a of the sleeve magnetic flux guide 165. Formed between.

  The shaft magnetic flux stopper 136 is formed in an annular flat plate shape using a nonmagnetic material such as austenitic stainless steel that can restrict the passage of the magnetic flux MF, and is attached to the outer peripheral portion 133a of the shaft main body 133 of the brake shaft 131 to be sleeve magnetic flux. It is surrounded from the outer peripheral side by a stopper 166. The axial thickness Tshs of the axial magnetic flux stopper 136 is thicker than the axial thickness Tshg of the axial magnetic flux guide 134 on the inner side of the housing with respect to the permanent magnet 163, and in the present embodiment, in particular, of the sleeve magnetic flux stopper 166. It is set to be substantially the same as the axial thickness Tslb of the bottom wall portion 168. At the same time, the outer diameter φshs of the shaft magnetic flux stopper 136 is smaller than the inner diameter φslb of the bottom wall portion 168 of the sleeve magnetic flux stopper 166. In particular, in this embodiment, the outer diameter φshg of the shaft magnetic flux guide 134 is set to be substantially the same. ing.

  With these settings, the axial end surface 136b on the outside of the housing of the axial magnetic flux stopper 136 is in surface contact with the axial end surface 134b on the inside of the housing of the axial magnetic flux guide 134 in the entire radial direction and rotational direction. That is, the axial magnetic flux stopper 136 is configured to cover the entire end surface 134b of the axial magnetic flux guide 134 from the outer peripheral portion 134a to the inner peripheral portion 134c from the inside of the housing. In addition, the outer peripheral portion 136a of the axial magnetic flux stopper 136 is configured as described above so that the radial width Wco in the longitudinal section is substantially the same as the radial width Wse of the seal gap 185 and substantially constant in the axial direction and the rotational direction. 186 is formed between the inner peripheral portion 168 a of the sleeve magnetic flux stopper 166. Here, the communication gap 186 extends over both the axial end faces 136b and 136c of the axial magnetic flux stopper 136 and the axial end faces 168b and 168c of the bottom wall portion 168 of the sleeve magnetic flux stopper 166. For this reason, in the present embodiment, the communication gap 186 having an axial length Lco longer than the axial length Lse of the seal gap 184 communicates the entire region between the fluid chamber 114 and the seal gap 184. It is.

  In the seal structure 160 having the configuration described above, as shown schematically in FIG. 5, the magnetic flux MF generated by the permanent magnet 163 passes through the sleeve magnetic flux guides 164 and 165 through the seal gaps 184 and 185 on the inner peripheral side. Guides 134 and 135 are guided. Here, the sleeve magnetic flux guides 164 and 165 and the axial magnetic flux guides 134 and 135 protrude toward the inner peripheral side and the outer peripheral side, respectively, and are close to each other, so that the magnetic flux MF is concentrated and guided to the seal gaps 184 and 185, respectively. Is possible.

  As shown in FIG. 7, the seal gaps 184 and 185 through which the magnetic flux MF passes at a high density by such guiding action are preliminarily shown by the magnetorheological fluid 140 introduced from the fluid chamber 114 communicating via the communication gap 186. be satisfied. Therefore, the magnetic particles 140a (see FIG. 7) in the magnetorheological fluid 140 satisfying the seal gaps 184 and 185 are trapped by the action of the magnetic flux MF passing through the gaps 184 and 185, thereby having high pressure resistance. A seal film is formed. Therefore, the seal film formed in each of the seal gaps 184 and 185 in this way exhibits a self-sealing function that suppresses the flow of the magnetorheological fluid 140 in the axial direction from the inside of the housing to the outside of the housing by the fluid itself. It can be done.

  Here, since the sleeve magnetic flux guide 164 inside the housing is covered from the inside of the housing by the sleeve magnetic flux stopper 166, the passage of the magnetic flux MF from the inner peripheral portion 164a is allowed to the seal gap 184 side. On the other hand, the inside of the housing in the axial direction is restricted. Similarly, since the axial magnetic flux guide 134 on the inner side of the casing is covered from the inner side of the casing by the axial magnetic flux stopper 136, the passage of the magnetic flux MF is allowed from the seal gap 184 side to the outer peripheral portion 134a. The inner side of the casing in the axial direction is restricted. As a result of such regulation, a case where the magnetic flux stoppers 166 and 136 are exposed to the fluid chamber 114 as shown in FIG. 6 from the inner peripheral portion 164a or the outer peripheral portion 134a of the magnetic flux guides 164 and 134 forming the seal gap 184. The magnetic flux MF leaking to the communication gap 186 between the magnetic flux stoppers 166 and 136 on the inner side is reduced. Therefore, it is possible to suppress the magnetic particles 140a from being collected from the communication gap 186 in the vicinity of the seal gap 184.

  Further, the communication gap 186 is longer than the seal gap 184 across the axial end faces 168b, 136b and the axial end faces 168c, 136c of the magnetic flux stoppers 166, 136 that are thicker in the axial direction than the magnetic flux guides 164, 134. It is formed in the direction length Lco. Therefore, in the communication gap 186 having substantially the same width Wco as the seal gap 184 in the entire axial direction from the fluid chamber 114 to the seal gap 184, the pressure loss during the flow of the magnetic particles 140a is increased to be greater than the seal gap 184. Will do. Therefore, the magnetic particles 140a in the fluid chamber 114 can also be prevented from reaching the inner peripheral portion 164a or the outer peripheral portion 134a of the magnetic flux guides 164 and 134 through the communication gap 186.

  According to the concentration suppressing action and the arrival suppressing action described so far, the sum of the magnetic attractive force Fm (see FIG. 5) for drawing each magnetic particle 140a on the inside of the housing into the seal gap 184 is determined by the seal gap 184. The sum of frictional forces Ff (see FIG. 7) acting between the magnetic flux guides 164 and 134 and the magnetic particles 140a or between the magnetic particles 140a can be suppressed to be smaller. Thereby, in the seal gap 184, it is difficult for leakage of the magnetic particles 140a to the outside of the housing due to the drawing of the magnetic particles 140a from the inside of the housing. Therefore, it is possible to maintain the self-sealing function of the high pressure-resistant sealing film formed by capturing the magnetic particles 140a and to avoid fluctuations in brake characteristics.

  In addition, in the seal structure 160, the communication gap 186 having substantially the same width Wco as the seal gap 184 is formed in the entire region between the elements 114 and 184 by the inner peripheral portion 168 a having an inner diameter φslb substantially equal to the sleeve magnetic flux guide 164 of the sleeve magnetic flux stopper 166. Is formed. Accordingly, any sliding resistance generated between the magnetic particles 140a flowing into the gaps 186 and 184 and the rotating brake shaft 131 can be suppressed to an appropriate magnitude. Therefore, it is possible to avoid the brake characteristics from fluctuating due to the sliding resistance generated between the inflowing particles 140a into the gaps 186 and 184 and the brake shaft 131.

  In addition, in the seal structure 160, the axial end face 164 b is not limited to the inner peripheral portion 164 a forming the seal gap 184 of the sleeve magnetic flux guide 164 but also on the outer peripheral side thereof by the sleeve magnetic flux stopper 166 on the inner side of the housing. Covered. According to this, it can suppress that the magnetic particle 140a is adsorb | sucked to the arbitrary locations of the axial direction end surface 164b, and the passage magnetic flux MF of the seal gap 184 changes. Similarly, the axial end face 134b is covered with the axial magnetic flux stopper 136 on the inner side of the housing not only on the outer peripheral portion 134a forming the seal gap 184 of the axial magnetic flux guide 134 but also on the outer peripheral side thereof. According to this, it is possible to prevent the magnetic particles 140a from being adsorbed at an arbitrary position on the axial end face 134b and the passing magnetic flux MF of the seal gap 184 from changing. Therefore, according to such a magnetic flux change suppressing action, it is possible to stably exhibit the self-sealing function of the seal film formed according to the passing magnetic flux MF of the seal gap 184, and to enhance the effect of avoiding fluctuations in brake characteristics. It becomes.

  As described above, in the valve timing adjusting device 1, it is possible to avoid the fluctuation of the brake characteristic by the fluid brake device 100 and maintain the adjustment accuracy of the engine phase influenced by the brake characteristic with high accuracy. Furthermore, according to the seal film formed by the magnetorheological fluid 140 in the fluid brake device 100, the sliding resistance applied to the rotating brake shaft 131 can be reduced, so that the fuel consumption of the internal combustion engine is caused by the sliding resistance. It is possible to avoid the torcross that causes a decrease.

(Second embodiment)
As shown in FIG. 8, the second embodiment of the present invention is a modification of the first embodiment. In the second embodiment, the bottom wall portion 2168 of the sleeve magnetic flux stopper 2166 has an inner diameter φslb2 smaller than the inner diameter φslg in addition to the inner diameter φslb1 substantially the same as the inner diameter φslg of the sleeve magnetic flux guide 164. With this setting, the bottom wall portion 2168 has a flat stepped surface 2168d between the inner peripheral portion 2168a1 having the inner diameter φslb1 and the inner peripheral portion 2168a2 having the inner diameter φslb2 on the inner side of the housing. Connected in the direction.

  Furthermore, in the brake shaft 2131 of the second embodiment, the outer diameter φshs of the outer peripheral portion 136a of the shaft magnetic flux stopper 2136 is larger than the inner diameter φslb2 of the inner peripheral portion 2168a2 of the bottom wall portion 2168, and the outer periphery 133a of the shaft main body 133 is outside. The diameter φshb is set smaller than the inner diameter φslb2. In the brake shaft 2131, the axial thickness Tshs of the axial magnetic flux stopper 2136 is set to be thicker than the axial thickness Tshg of the axial magnetic flux guide 134, but thinner than the axial thickness Tslb of the bottom wall portion 168. . With these settings, the communication gap 2186 is stepped between the outer peripheral portion 136 a and the inner peripheral portion 2168 a 1, between the outer peripheral portion 133 a and the inner peripheral portion 2168 a 2, and the axial end surface 2136 c on the inner side of the casing of the axial magnetic flux stopper 2136. It is formed between the surface 2168d.

  Here, between the outer peripheral portion 136a and the inner peripheral portion 2168a1, the radial width Wco1 in the longitudinal section of the communication gap 2186 is substantially the same as the radial width Wse of the seal gap 184 and substantially constant in the axial direction and the rotational direction. It has become. Further, between the outer peripheral portion 133a and the inner peripheral portion 2168a2, the radial width Wco2 in the longitudinal section of the communication gap 2186 is substantially the same as the radial width Wse of the seal gap 184 and substantially constant in the axial direction and the rotational direction. ing. Further, between the axial end surface 2136c and the stepped surface 2168d, the axial width Wco3 in the longitudinal section of the communication gap 2186 is substantially the same as the radial width Wse of the seal gap 184 and substantially constant in the radial direction and the rotational direction. ing.

  As described above, in the second embodiment, the labyrinth-like communication gap 2186 meandering the entire region between the fluid chamber 114 and the seal gap 184 across the both end faces 168b and 168c of the bottom wall portion 2168 is the axial length of the seal gap 184. It is formed in the full length longer than Lse. Therefore, also in the second embodiment, the same concentration suppression and arrival suppression action as in the first embodiment can be obtained, so that it is possible to maintain the self-sealing function of the high pressure-resistant sealing film and avoid the fluctuation of the brake characteristics. .

  Furthermore, since the communication gap 2186 of the second embodiment is as long as possible between the fluid chamber 114 and the seal gap 184 due to the labyrinth-like meandering form, the pressure loss during the flow of the magnetic particles can be increased. Therefore, it is possible to enhance the effect of suppressing the arrival of the magnetic particles 140a with respect to the inner peripheral portion 164a or the outer peripheral portion 134a of each of the magnetic flux guides 164 and 134, and hence the effect of avoiding fluctuations in brake characteristics.

  In addition, the inner peripheral portions 2168a1 and 2168a2 of the sleeve magnetic flux stopper 2166 forming the communication gap 2186 in the second embodiment are formed to have relatively small inner diameters φslb1 and φslb2 below the sleeve magnetic flux guide 164. According to this, since the sliding resistance given to the rotating brake shaft 131 by the magnetic particles 140a flowing into the communication gap 2186 can be kept small, it is possible to avoid fluctuations in brake characteristics due to the sliding resistance. It is.

(Third embodiment)
As shown in FIG. 9, the third embodiment of the present invention is a modification of the second embodiment. In the third embodiment, the bottom wall portion 3168 of the sleeve magnetic flux stopper 3166 is provided with a plurality of inner peripheral portions 2168a1 having an inner diameter φslb1 and a plurality of inner peripheral portions 2168a2 having an inner diameter φslb2 in the axial direction. They are connected to each other by 2168d. In addition, axial magnetic flux stoppers 2136 are individually provided at a plurality of locations on the inner peripheral side of each inner peripheral portion 2168a2 in the brake shaft 3131. With these configurations, the communication gap 3186 is provided between the outer peripheral portion 136a and each inner peripheral portion 2168a1 of each axial magnetic flux stopper 2136, between the outer peripheral portion 133a and each inner peripheral portion 2168a2 of the shaft main body 133, and each axial magnetic flux stopper. 2136 is formed between the axial end surfaces 2136c and 136b and the stepped surfaces 2168d.

  As described above, in the third embodiment, the labyrinth-like communication gap 3186 meandering the entire area between the fluid chamber 114 and the seal gap 184 across the both end faces 168b and 168c of the bottom wall portion 3168 is the axial length of the seal gap 184. The total length is sufficiently longer than Lse. Therefore, according to the third embodiment, the pressure loss at the time of magnetic particle flow is remarkably increased by the communication gap 3186, and the arrival suppressing action of the magnetic particles 140a on the inner peripheral portion 164a or the outer peripheral portion 134a of each magnetic flux guide 164, 134 As a result, it is possible to enhance the effect of avoiding fluctuations in brake characteristics.

(Fourth embodiment)
As shown in FIGS. 10 and 11, the fourth embodiment of the present invention is a modification of the first embodiment. The magnetic seal sleeve 4162 of the fourth embodiment further includes a sleeve magnetic flux stopper 4166 different from the sleeve magnetic flux stopper 166. The cylindrical sleeve magnetic flux stopper 4166 is disposed on the inner peripheral side of the permanent magnet 163 between the sleeve magnetic flux guides 164 and 165 disposed on the inner side and the outer side of the permanent magnet 163, and the magnet 163. The inner peripheral portion 163a is coaxially mounted to surround the outer peripheral side of the shaft main body 133. The axial thickness Tsls of the sleeve magnetic flux stopper 4166 is set to be thicker than the axial thickness Tslg of each of the sleeve magnetic flux guides 164 and 165. In particular, in the present embodiment, it is substantially the same as the axial thickness Tslm of the permanent magnet 163. Is set. At the same time, the inner diameter φsls of the inner peripheral portion 4166a of the sleeve magnetic flux stopper 4166 is set to be substantially the same as the inner diameter φslg of the inner peripheral portions 164a and 165a of the sleeve magnetic flux guides 164 and 165.

  With these settings, the axial end surface 4166c of the sleeve magnetic flux stopper 4166 on the inner side of the housing is radially aligned with the axial end surface 164d on the outer side of the housing of the portion 164a that protrudes from the permanent magnet 163 in the sleeve magnetic flux guide 164. In addition, surface contact is made in the entire rotation direction. That is, the sleeve magnetic flux stopper 4166 covers the entire inner peripheral portion 164a as a protruding portion of the sleeve magnetic flux guide 164 from the outside of the housing. Further, the axial end surface 4166b of the sleeve magnetic flux stopper 4166 on the outer side of the housing is radially and in the rotational direction of the axial end surface 165b on the inner side of the housing of the portion 165a protruding from the permanent magnet 163 in the sleeve magnetic flux guide 165. The surface is in contact with the whole area. That is, the sleeve magnetic flux stopper 4166 is configured to cover the entire inner peripheral portion 165a as a protruding portion of the sleeve magnetic flux guide 165 from the inside of the housing.

  The brake shaft 4131 of the fourth embodiment further includes an axial magnetic flux stopper 4136 different from the axial magnetic flux stopper 136. A cylindrical shaft magnetic flux stopper 4136 is mounted on the shaft main body 133 between the shaft magnetic flux guides 134 and 135 protruding toward the sleeve magnetic flux guides 164 and 165, and is surrounded from the outer peripheral side by the coaxial sleeve magnetic flux stopper 4166. ing. The axial thickness Tshs of the axial magnetic flux stopper 4136 is thicker than the axial thickness Tshg of the axial magnetic flux guides 134 and 135. In particular, in this embodiment, the axial thickness Tslm of the permanent magnet 163 and the sleeve magnetic flux stopper 4166 It is set to be substantially the same as the axial thickness Tsls. At the same time, the outer diameter φshs of the outer peripheral portion 4136a of the axial magnetic flux stopper 4136 is smaller than the inner diameter φslb of the inner peripheral portion 4166a of the sleeve magnetic flux stopper 4166. In particular, in this embodiment, the outer peripheral portions 134a, It is set to be substantially the same as the outer diameter φshg of 135a.

  With these settings, the axial end surface 4136c inside the housing of the axial magnetic flux stopper 4136 is in surface contact with the axial end surface 134d outside the housing of the axial magnetic flux guide 134 in the entire radial and rotational directions. That is, the axial magnetic flux stopper 4136 covers the entire end surface 134d of the axial magnetic flux guide 134 from the outer peripheral portion 134a to the inner peripheral portion 134c from the outside of the housing. The axial end surface 4136b of the axial magnetic flux stopper 4136 on the outer side of the housing is in surface contact with the axial end surface 135b of the axial magnetic flux guide 135 on the inner side of the housing in the entire radial direction and rotational direction. That is, the axial magnetic flux stopper 4136 covers the entire end surface 135b of the axial magnetic flux guide 135 from the outer peripheral portion 135a to the inner peripheral portion 135c from the inside of the housing.

  With the configuration described so far, the communication gap 4186 between the outer peripheral portion 4136a of the axial magnetic flux stopper 4136 and the inner peripheral portion 4166a of the sleeve magnetic flux stopper 4166 has a radial width Wco in the longitudinal section of the radial gap Wse of the seal gap 185. And a substantially cylindrical shape that is substantially the same in the axial direction and the rotational direction. Here, the communication gap 4186 extends over both the axial end faces 4136b and 4136c of the axial magnetic flux stopper 4136 and the axial end faces 4166b and 4166c of the sleeve magnetic flux stopper 166. For this reason, the communication gap 4186 having an axial length Lco that is longer than the axial length Lse of the seal gap 185 on the outside of the casing is formed between the seal gap 185 and the fluid chamber 114 inside the casing. It communicates via gaps 186 and 184 on the part side.

  As described above, in the fourth embodiment, the inner peripheral portion 165a protruding from the permanent magnet 163 in the sleeve magnetic flux guide 165 on the outer side of the casing is covered with the sleeve magnetic flux stopper 4166 from the inner side of the casing. The passage of magnetic flux MF from 165a to the inside of the housing is restricted. Similarly, since the axial magnetic flux guide 135 protruding from the shaft main body 133 on the outside of the housing is covered from the inside of the housing by the axial magnetic flux stopper 4136, the magnetic flux MF from the axial magnetic flux guide 135 to the inside of the housing is the same. Will be restricted. As a result of such restriction, the inner periphery 165a of the sleeve magnetic flux guide 165 and the outer peripheral portion 135a of the axial magnetic flux guide 135 that form the seal gap 185 are spaced between the magnetic flux stoppers 4166 and 4136 on the inner peripheral side of the permanent magnet 163. The magnetic flux MF that leaks into the communication gap 4186 of the first is reduced. Therefore, it is possible to suppress the magnetic particles 140a in the magnetorheological fluid 140 from being concentrated in the vicinity of the seal gap 185 from the communication gap 4186. At the same time, in the fourth embodiment, similarly to the first embodiment, it is possible to suppress the magnetic particles 140a in the magnetorheological fluid 140 from reaching the vicinity of the seal gap 184 from the communication gap 186 and collecting them.

  According to such a concentration suppressing action, even if the seal gaps 184 and 185 have a high passing magnetic flux density due to the protrusions of the axial magnetic flux guides 134 and 135, the magnetic particles on the inner side of the permanent magnet 163 are arranged on the inner side of the casing. The magnetic attractive force Fm (see FIG. 10) that pulls in 140a can be kept small. Therefore, the self-sealing function by the high pressure-resistant sealing film can be maintained, and the effect of avoiding fluctuations in brake characteristics can be enhanced.

  In addition, since the inner peripheral portions 164a and 165a of the sleeve magnetic flux guides 164 and 165 are covered with the sleeve magnetic flux stopper 4166 from the outer side of the casing and the inner side of the casing, respectively, between the inner peripheral portions 164a and 165a. The short circuit of the magnetic flux MF through the magnetic particles 140a is restricted. Similarly, since the axial magnetic flux guides 134 and 135 are respectively covered with 4136 from the outside of the housing and the inside of the housing, the magnetic flux MF through the magnetic particles 140a between the axial magnetic flux guides 134 and 135 is covered. Is short circuited. As a result, the magnetic flux leakage in the axial direction is suppressed between the sleeve magnetic flux guides 164 and 165 and between the axial magnetic flux guides 134 and 135, and as described above, the magnetic particles 140a are concentrated near the seal gaps 184 and 185. Therefore, the leakage of the magnetic particles 140a from the gaps 184 and 185 is difficult to occur. Therefore, it is possible to enhance the effect of avoiding fluctuations in brake characteristics.

(Fifth embodiment)
As shown in FIG. 12, the fifth embodiment of the present invention is a modification of the fourth embodiment. In the fifth embodiment, the inner diameter φsls of the inner peripheral portion 5166a of the sleeve magnetic flux stopper 5166 is smaller than the inner diameter φslg of the inner peripheral portions 164a, 165a of the sleeve magnetic flux guides 164, 165, and the outer peripheral portions of the axial magnetic flux guides 134, 135. It is set to be larger than the outer diameter φshg of 134a, 135a. With this setting, the communication gap 5186 between the inner peripheral portion 5166a of the sleeve magnetic flux stopper 5166 and the outer peripheral portion 4136a of the axial magnetic flux stopper 4136 has a radial width Wco in the longitudinal section smaller than the radial width Wse of the seal gap 185. Further, it is formed in a cylindrical shape that is substantially constant in the axial direction and the rotational direction.

  According to the fifth embodiment, in addition to the concentration suppressing action described in the fourth embodiment, a high arrival suppressing action by the communication gap 5186 having a narrow radial width Wco is obtained. Therefore, it becomes possible to maintain the self-sealing function of the high pressure-resistant sealing film and enhance the effect of avoiding fluctuations in brake characteristics.

(Sixth embodiment)
As shown in FIG. 13, the sixth embodiment of the present invention is a modification of the fourth embodiment. In the sixth embodiment, the stepped cylindrical sleeve magnetic flux stopper 6166 is a rush portion 6168 that protrudes from the main body portion 6167 to the inner peripheral side with respect to the main body portion 6167 having substantially the same configuration as the sleeve magnetic flux stopper 4166 of the fourth embodiment. A combination of The axial thickness Tsls1 of the intrusion portion 6168 is set to be thinner than the axial thickness Tsls2 of the main body portion 6167. At the same time, the inner diameter φsls of the inner peripheral portion 6168a of the rush portion 6168 is set smaller than the outer diameter φshg of the outer peripheral portions 134a, 135a of the axial magnetic flux guides 134, 135. With these settings, the rush portion 6168 has a shape that pierces between the magnetic flux guides 134 and 135.

  In the sixth embodiment, the cylindrical shaft magnetic flux stopper 6136 is set such that the outer diameter φshs of the outer peripheral portion 6136a is smaller than the inner diameter φsls of the inner peripheral portion 6168a of the protruding portion 6168 and the outer diameter φshg of the axial magnetic flux guides 134 and 135. The configuration is substantially the same as the axial magnetic flux stopper 4136 of the fourth embodiment. With this setting, the axial end surface 6136c on the inner side of the casing of the axial magnetic flux stopper 6136 is in surface contact with the axial end face 134d on the outer side of the casing of the axial magnetic flux guide 134 in a part of the radial direction and in the entire rotation direction. Yes. That is, the axial magnetic flux stopper 6136 is configured to cover an inner peripheral portion of the end surface 134d of the axial magnetic flux guide 134 with respect to the outer peripheral portion 134a from the outside of the housing. The axial end surface 6136b of the axial magnetic flux stopper 6136 on the outer side of the housing is in surface contact with the axial end surface 135b of the axial magnetic flux guide 135 on the inner side of the housing in a part of the radial direction and in the entire rotation direction. That is, the axial magnetic flux stopper 6136 is configured to cover an inner peripheral side portion of the end surface 135b of the axial magnetic flux guide 135 with respect to the outer peripheral portion 135a from the inside of the housing.

  Under the configuration described so far, the communication gap 6186 is formed between the axial end surface 134d and the axial end surface 6168c on the housing inner side of the protrusion 6168, between the outer peripheral portion 6136a and the inner peripheral portion 6168a, and the axial end surface. It is formed between 135b and the axial end surface 6168b on the outside of the housing of the entry portion 6168. Specifically, between the axial end faces 134d and 6168c, the axial width Wco1 in the longitudinal section of the communication gap 6186 is smaller than the radial width Wse of the seal gap 185 and substantially constant in the radial direction and the rotational direction. It has become. Between the outer peripheral portion 6136a and the inner peripheral portion 6168a, the radial width Wco2 in the longitudinal section of the communication gap 6186 is smaller than the radial width Wse of the seal gap 185 and substantially constant in the axial direction and the rotational direction. . Between the axial end faces 135b and 6168b, the axial width Wco3 in the longitudinal section of the communication gap 6186 is smaller than the radial width Wse of the seal gap 185 and substantially constant in the radial direction and the rotational direction.

  As described above, in the sixth embodiment, the labyrinth communication gap 6186 meandering across the both end faces 4166b and 4166c of the main body portion 6167 of the sleeve magnetic flux stopper 6166 is provided between the fluid chamber 114 and the seal gap 185 from the seal gap 185. Is also formed long. Therefore, also in the sixth embodiment, since the concentration suppressing action and the arrival suppressing action described in the fourth embodiment are obtained, it is possible to maintain the self-sealing function of the high pressure-resistant sealing film and avoid the fluctuation of the brake characteristics. .

  In addition, in the sixth embodiment, when the sleeve magnetic flux stopper 6166 enters between the axial magnetic flux guides 134 and 135, the short circuit of the magnetic flux MF through the magnetic particles 140a is regulated between the axial magnetic flux guides 134 and 135. . As a result, the leakage of the magnetic flux in the axial direction is suppressed both between the sleeve magnetic flux guides 164 and 165 and between the axial magnetic flux guides 134 and 135, and the seal gap of the magnetic particles 140a as described in the fourth embodiment. Concentration in the vicinity of 185 is also suppressed. According to such a suppressing action, it is difficult for leakage of the magnetic particles 140a from the seal gaps 184 and 185, so that it is possible to increase the effect of avoiding fluctuations in brake characteristics.

(Seventh embodiment)
As shown in FIG. 14, the seventh embodiment of the present invention is a modification of the sixth embodiment. In the seventh embodiment, the sleeve magnetic flux stopper 7166 has an inner diameter φsls2 that is substantially the same as the inner diameter φslg of the sleeve magnetic flux guides 164 and 165, in addition to the inner diameter φsls1 smaller than the outer diameter φshg of the axial magnetic flux guides 134 and 135. Has been. With this setting, in the sleeve magnetic flux stopper 7166, the space between the inner peripheral portion 7168a of the intrusion portion 7168 having the inner diameter φsls1 and the inner peripheral portion 6167a of the main body portion 6167 having the inner diameter φsls2 on the outside of the housing is flat. They are connected in the radial direction by a planar stepped surface 7168d.

  In the seventh embodiment, the axial magnetic flux stopper 7136 has an outer diameter φshs2 larger than the outer diameter φshg of each axial magnetic flux guide 134, 135 in addition to the outer diameter φshs1 smaller than the outer diameter φshg of each axial magnetic flux guide 134, 135. Is set. With this setting, the axial magnetic flux stopper 7136 has a flat stepped surface 7136d between the outer peripheral portion 7136a1 having the outer diameter φshs1 and the outer peripheral portion 7136a2 having the outer diameter φshs2 on the outside of the housing. Connected in the direction. At the same time, the axial end surface 7136b on the outside of the housing of the axial magnetic flux stopper 7136 is in surface contact with the axial end surface 135b on the inside of the housing of the axial magnetic flux guide 135 in the entire radial and rotational directions. That is, the axial magnetic flux stopper 7136 covers the entire end surface 135b from the outer peripheral portion 135a to the inner peripheral portion 135c of the axial magnetic flux guide 135 from the inside of the housing.

  Under the configuration described so far, the communication gap 7186 is formed between the axial end surface 134d and the axial end surface 6168c of the protruding portion 7168, between the outer peripheral portion 7136a1 and the inner peripheral portion 7168a, between the step surfaces 7168d and 7136d, and It is formed between the outer peripheral part 7136a2 and the inner peripheral part 6167a. Specifically, between the axial end faces 134d and 6168c, the axial width Wco1 in the longitudinal section of the communication gap 7186 is smaller than the radial width Wse of the seal gap 185 and substantially constant in the radial direction and the rotational direction. It has become. Between the outer peripheral portion 7136a1 and the inner peripheral portion 7168a, the radial width Wco2 in the longitudinal section of the communication gap 7186 is smaller than the radial width Wse of the seal gap 185 and substantially constant in the axial direction and the rotational direction. . Between the step surfaces 7168d and 7136d, the axial width Wco3 in the longitudinal section of the communication gap 7186 is smaller than the radial width Wse of the seal gap 185 and substantially constant in the radial direction and the rotational direction. Between the outer peripheral portion 7136a2 and the inner peripheral portion 6167a, the radial width Wco4 in the longitudinal section of the communication gap 7186 is smaller than the radial width Wse of the seal gap 185 and substantially constant in the axial direction and the rotational direction. .

  As described above, in the seventh embodiment, the labyrinth-like communication gap 7186 meandering across the both end faces 4166b and 4166c of the main body portion 6167 of the sleeve magnetic flux stopper 7166 is provided between the fluid chamber 114 and the seal gap 185 from the seal gap 185. Is also formed long. Therefore, also in the seventh embodiment, the same operation as in the sixth embodiment can be obtained, so that it is possible to maintain the self-sealing function of the high pressure-resistant sealing film and enhance the effect of avoiding fluctuations in brake characteristics.

(Eighth embodiment)
As shown in FIG. 15, the eighth embodiment of the present invention is a modification of the seventh embodiment. In the sleeve magnetic flux stopper 8166 of the eighth embodiment, the axial thickness Tsls2 of the main body 8167 is thicker than the axial thickness Tslg of the sleeve magnetic flux guides 164 and 165, but is larger than the axial thickness Tslm of the permanent magnet 163. It is set thinly. Further, according to such setting, the main body 8167 covers the inner peripheral portion 165a of the sleeve magnetic flux guide 165 from the inner side of the housing, but from the inner peripheral portion 164a of the sleeve magnetic flux guide 164 to the axial direction inside the housing. The end surface 8166c is separated to the outside of the housing.

  In the eighth embodiment, the axial thickness Tshs of the axial magnetic flux stopper 8136 is set to be thicker than the axial thickness Tslg of the axial magnetic flux guides 134 and 135, but thinner than the axial thickness Tslm of the permanent magnet 163. Yes. Further, the axial magnetic flux stopper 8136 covers the axial magnetic flux guide 134 from the outside of the housing in accordance with such setting, but the axial end surface 8136b on the outside of the housing is formed from the axial magnetic flux guide 135 and the sleeve magnetic flux stopper 8166. It is separated from the inside of the housing. Further, the axial magnetic flux stopper 8136 is configured such that the outer diameter φshs2 of the outer peripheral portion 7136a2 is set larger than the inner diameter φslg of the inner peripheral portions 164a and 165a of the sleeve magnetic flux guides 164 and 165. It has a rushed form.

  In the configuration described so far, the communication gap 8186 is formed between the axial end surface 164d and the stepped surface 7136d, between the outer peripheral portion 7136a2 and the inner peripheral portion 163a, between the axial end surfaces 8136b and 8166c, and the inner peripheral portion 7168a. It is formed between the outer peripheral portion 133a and between the step surface 7168d and the axial end surface 135b. Specifically, between the axial end surface 164d and the stepped surface 7136d, the axial width Wco1 in the longitudinal section of the communication gap 8186 is smaller than the radial width Wse of the seal gap 185 and in the radial direction and the rotational direction. It is virtually constant. Between the outer peripheral portion 7136a2 and the inner peripheral portion 163a, the radial width Wco2 in the longitudinal section of the communication gap 8186 is smaller than the radial width Wse of the seal gap 185 and substantially constant in the axial direction and the rotational direction. . Between the axial end faces 8136b and 8166c, the axial width Wco3 in the longitudinal section of the communication gap 8186 is smaller than the radial width Wse of the seal gap 185 and substantially constant in the radial direction and the rotational direction. Between the inner peripheral portion 7168a and the outer peripheral portion 133a, the radial width Wco4 in the longitudinal section of the communication gap 8186 is smaller than the radial width Wse of the seal gap 185 and substantially constant in the axial direction and the rotational direction. . Between the step surface 7168d and the axial end surface 135b, the axial width Wco5 in the longitudinal section of the communication gap 8186 is smaller than the radial width Wse of the seal gap 185 and substantially constant in the radial direction and the rotational direction. .

  As described above, in the eighth embodiment, the labyrinth communication gap 8186 meandering between the fluid chamber 114 and the seal gap 185 is formed longer than the seal gap 185. Therefore, according to the eighth embodiment, the same operation as that of the sixth embodiment can be obtained. Therefore, it is possible to maintain the self-sealing function of the high pressure-resistant sealing film and enhance the effect of avoiding fluctuations in brake characteristics.

(Ninth embodiment)
As shown in FIG. 16, the ninth embodiment of the present invention is a modification of the sixth embodiment. The brake shaft 9131 of the ninth embodiment is not provided with an axial magnetic flux stopper 6136. Accordingly, the communication gap 9186 is formed between the inner peripheral portion 6168a of the nonmagnetic rubber stopper 9166 and the outer peripheral portion 133a of the shaft main body 133 in addition to between the axial end surfaces 134d and 6168c and between the axial end surfaces 135b and 6168b. Is formed between. Here, between the outer peripheral portion 133a and the inner peripheral portion 6168a, the radial width Wco2 in the longitudinal section of the communication gap 9186 is smaller than the radial width Wse of the seal gap 185 and substantially constant in the axial direction and the rotational direction. It has become.

  Therefore, in the ninth embodiment, a labyrinth communication gap 9186 meandering across the both end surfaces 4166b and 4166c of the body portion 6167 of the sleeve magnetic flux stopper 9166 between the fluid chamber 114 and the seal gap 185, It is longer than the seal gap 185. Therefore, according to the ninth embodiment, the same action as in the sixth embodiment can be obtained except for the action by the axial magnetic flux stopper 4136 described in the fourth embodiment, so that the self-sealing function of the high pressure-resistant sealing film is maintained. It is possible to increase the effect of avoiding fluctuations in 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, the sleeve magnetic flux stoppers 166, 2166, and 3166 of the first to third embodiments may be formed only from the bottom wall portions 168, 2168, and 3168 without providing the peripheral wall portion 167.

  As shown in a modified example in FIG. 17, in the first embodiment, instead of providing the axial magnetic flux stopper 136, the radial width Wco is set between the inner peripheral portion 168 a of the sleeve magnetic flux stopper 166 and the outer peripheral portion 133 a of the shaft main body 133. A cylindrical communication gap 186 may be formed, and an annular communication gap 186 having an axial width Wco may be formed between the axial magnetic flux guide 134 thinner than the sleeve magnetic flux guide 164 and the sleeve magnetic flux stopper 166. .

  As shown in a modified example in FIG. 18, in the first embodiment, instead of providing the axial magnetic flux stopper 136 and the axial magnetic flux guides 134 and 135, the inner peripheral portions 164 a and 165 a of the sleeve magnetic flux guides 164 and 165 and the outer periphery of the shaft main body 133. Annular seal gaps 184 and 185 having a radial width Wse are formed between the portion 133a and a cylindrical member having a radial width Wco between the inner peripheral portion 168a of the sleeve magnetic flux stopper 166 and the outer peripheral portion 133a of the shaft main body 133. A continuous communication gap 186 may be formed. In addition, about the structure of this modification, the same structure is employ | adopted also in FIG. 26 mentioned later.

  19 and 20, in the first embodiment, a tapered communication gap 186 having a radial width Wco is provided between the inner peripheral portion 168a of the sleeve magnetic flux stopper 166 and the outer peripheral portion 136a of the axial magnetic flux stopper 136. May be formed. In this case, as shown in FIG. 19, by reducing the inner diameter φslb of the inner peripheral portion 168a of the sleeve magnetic flux stopper 166 and the outer diameter φshs of the outer peripheral portion 136a of the axial magnetic flux stopper 136 toward the inside of the housing, a tapered shape is obtained. A communication gap 186 may be formed. Alternatively, as shown in FIG. 20, by increasing the inner diameter φslb of the inner peripheral portion 168a of the sleeve magnetic flux stopper 166 and the outer diameter φshs of the outer peripheral portion 136a of the axial magnetic flux stopper 136 toward the inner side of the housing, a tapered communication gap is obtained. 186 may be formed.

  As shown in a modified example in FIG. 21, in the third embodiment, the outer diameter φshs of the outer peripheral portion 136a is set as the axial magnetic flux for at least one of the plurality of axial magnetic flux stoppers 2136 excluding the axial magnetic flux stopper 2136 on the outermost side of the housing. A radial width Wco1 between the inner peripheral portion 3168a3 formed with the inner diameter φslb3 of the bottom wall portion 3168 of the sleeve magnetic flux stopper 3166 and the outer peripheral portion 136a is larger than the outer diameter φshg of the outer peripheral portion 134a of the guide 134. A cylindrical communication gap 3186 may be formed.

  22 and 23, in the first embodiment, a communication gap 186 having a radial width Wco that is smaller than the radial width Wse of the seal gap 185 in the longitudinal section may be formed. In this case, as shown in FIG. 22, the inner diameter φslb of the bottom wall portion 168 of the sleeve magnetic flux stopper 166 is smaller than the inner diameter φslg of the sleeve magnetic flux guide 164 in a range larger than the outer diameter φshs of the axial magnetic flux stopper 136. By setting, the radial width Wco of the communication gap 186 may be smaller than the radial width Wse of the seal gap 185. Alternatively, as shown in FIG. 23, the outer diameter φshs of the axial magnetic flux stopper 136 is set larger than the outer diameter φshg of the axial magnetic flux guide 134 in a range smaller than the inner diameter φslb of the bottom wall portion 168 of the sleeve magnetic flux stopper 166. By doing so, the radial width Wco of the communication gap 186 may be smaller than the radial width Wse of the seal gap 185.

  In the second and third embodiments and the modified examples other than FIGS. 22 and 23, the widths Wco, Wco1, Wco2, which are smaller than the radial width Wse of the seal gap 185, according to the modified examples of FIGS. Communication gaps 186, 2186, 3186 of Wco3 may be formed.

  24, in the fourth to ninth embodiments (FIG. 24 is an example of the fourth embodiment), the inner peripheral portion 168a of the bottom wall portion 168 has an inner diameter φslb of the inner peripheral portion 164a of the sleeve magnetic flux guide 164. A configuration in which the communication gap 186 is not formed may be employed by employing the sleeve magnetic flux stopper 166 that is larger than the inner diameter φslg. Alternatively, in the fourth to ninth embodiments, a configuration in which the sleeve magnetic flux stopper 2166 of the second embodiment, the sleeve magnetic flux stopper 3166 of the third embodiment, or the above modification of those embodiments is provided instead of the sleeve magnetic flux stopper 166, or the sleeve A configuration in which the magnetic flux stopper 166 itself is not provided may be employed.

  As shown in a modified example in FIG. 25, in the fourth and fifth embodiments (FIG. 25 is an example of the fifth embodiment), the axial magnetic flux stopper 4136 is not provided, and the axial magnetic flux guides 134 and 135 are arranged in the axial direction. You may employ | adopt the structure which provided the axial magnetic flux guide 138 formed by connection. In this case, annular seal gaps 184 and 185 having a radial width Wse are formed between the inner peripheral portions 164a and 165a of the sleeve magnetic flux guides 164 and 165 and the outer peripheral portion 138a of the axial magnetic flux guide 138, and the sleeve magnetic flux stopper 4166 is formed. , 5166 is formed with cylindrical communication gaps 4186, 5186 having a radial width Wco equal to or less than the radial width Wse between the inner peripheral portions 4166a, 5166a of the axial magnetic flux guide 138. it can.

  As shown in FIG. 26, in the fourth and fifth embodiments (FIG. 26 is an example of the fifth embodiment), a configuration in which the axial magnetic flux stopper 4136 and the axial magnetic flux guides 134 and 135 are not provided may be adopted. Good. In this case, annular seal gaps 184 and 185 having a radial width Wse are formed between the inner peripheral portions 164a and 165a of the sleeve magnetic flux guides 164 and 165 and the outer peripheral portion 133a of the shaft main body 133, and sleeve magnetic flux stoppers 4166, A configuration in which cylindrical communication gaps 4186 and 5186 having a radial width Wco equal to or less than the radial width Wse can be formed between the inner peripheral portions 4166a and 5166a of the 5166 and the outer peripheral portion 133a of the shaft main body 133 can be employed.

  As shown in FIG. 27, in the sixth to ninth embodiments and the above-described modified examples of these embodiments (FIG. 27 is an example of the sixth embodiment), the communication gap 6186 is similar to the fourth embodiment. The width of 7186, 8186, 9186 (Wco1, Wco2, Wco3 in the example of FIG. 27) may be set to be substantially the same as the width Wse of the seal gap 185.

  As shown in a modified example in FIG. 28, the eighth embodiment has a configuration in which the inside of the housing and the outside of the housing are reversed with respect to the magnetic flux stoppers 8166 and 8136 (that is, the left and right are reversed with respect to FIG. 15). , May be adopted.

  29, in the fourth to ninth embodiments (FIG. 29 is an example of the ninth embodiment), at least one opening toward the communication gap 4186, 5186, 6186, 7186, 8186, 9186 is shown. A slit 188 may be provided in the sleeve magnetic flux stoppers 4166, 5166, 6166, 7166, 8166, 9166 and / or the axial magnetic flux stoppers 4136, 6136, 7136, 8136.

  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”, 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, 114 fluid chamber, 130 brake rotating body, 131, 1311, 3131, 4131, 9131 brake shaft, 133 shaft body, 133a, 134a, 135a, 136a, 138a, 163c, 164c, 165c, 4136a, 4166d, 6136a, 7136a1, 7136a2 outer peripheral part, 134, 135, 138 axial magnetic flux guide, 134b, 134d, 135b, 136b, 136c, 164b, 164d, 165b, 168b, 168c , 2136c, 4136b, 4136c, 4166b, 4166c, 6136b, 6136c, 6168b, 6168c, 7136b, 8136b, 8166c end face, 134c, 135c, 163a, 164 a, 165a, 168a, 2168a1, 2168a2, 3168a3, 4166a, 5166a, 6167a, 6168a, 7168a Inner circumference, 136, 2136, 4136, 6136, 7136, 8136 Axial magnetic flux stopper, 140 Magnetorheological fluid, 140a Magnetic particle, 150 Solenoid coil (viscosity control means), 160 Seal structure, 162, 4162 Magnetic seal sleeve, 163 Permanent magnet, 164, 165 Sleeve magnetic flux guide, 166, 2166, 3166, 4166, 5166, 6166, 7166, 8166, 9166 Sleeve magnetic flux stopper , 184,185 Seal gap, 186, 2186, 3186, 4186, 5186, 6186, 7186, 8186, 9186 Communication gap, 188 slit, 200 Electric control circuit (viscosity control means), 300 phase adjustment mechanism, 2168d, 7136d, 7168d stepped surface, 6167, 8167 main body, 6168, 7168 rush, Ff friction force, Fm magnetic attraction force, MF magnetic flux, N, S magnetic pole , Tslb, Tslg, Tslm, Tslp, Tsls, Tsls1, Tsls2, Tshg, Tshs Axial thickness, Wco, Wco1, Wco2, Wco3, Wco4, Wco5, Wse width, φshb, φshg, φshs, shs1, sh Diameter, φslb, φslb1, φslb2, φslb3, φslg, φslm, φslp, φsls, φsls1, φsls2

Claims (14)

A housing that forms a fluid chamber therein;
A magnetorheological fluid in which magnetic particles are dispersed in a base liquid, enclosed in the fluid chamber, and the viscosity changes according to the magnetic flux passing through;
Viscosity control means for variably controlling the viscosity of the magnetorheological fluid by passing magnetic flux through the fluid chamber;
A brake rotating body having a brake shaft that penetrates the housing in and out in the axial direction, to which a brake torque according to the viscosity of the magnetorheological fluid is input by contacting the magnetorheological fluid in the fluid chamber;
A fluid brake device comprising: a magnetic seal sleeve that is held by the housing and surrounds an outer peripheral side of the brake shaft and generates a magnetic flux that guides the brake shaft;
The magnetic seal sleeve is
A magnetic flux guide that has an inner peripheral portion that forms the seal gap between the brake shaft and guides the magnetic flux from the inner peripheral portion to the brake shaft through the seal gap;
Covering the inner peripheral portion of the magnetic flux guide from the inside of the housing to restrict the passage of magnetic flux from the inner peripheral portion to the inside of the housing, and a communication gap for communicating the fluid chamber with the seal gap A fluid brake having a magnetic flux stopper formed between the brake shaft and a magnetic flux stopper that gives the communication gap a width equal to or smaller than the seal gap in a longitudinal section along the axial direction of the brake shaft. apparatus.   2. The fluid brake device according to claim 1, wherein the magnetic flux stopper has an inner peripheral portion that is formed with an inner diameter equal to or smaller than the magnetic flux guide and sandwiches the communication gap with the brake shaft.   3. The fluid brake according to claim 2, wherein the magnetic flux stopper has an inner peripheral portion that is formed to have the same inner diameter as the magnetic flux guide and that gives the communication gap the same width as the seal gap in the longitudinal section. apparatus.   The fluid brake device according to any one of claims 1 to 3, wherein the communication gap is formed across both end faces of the magnetic flux stopper that is thicker than the magnetic flux guide in the axial direction.   The fluid brake device according to any one of claims 1 to 4, wherein the magnetic flux stopper forms the communication gap in a labyrinth shape meandering between the fluid chamber and the seal gap.   The fluid brake device according to any one of claims 1 to 5, wherein the magnetic flux stopper covers the entire end surface of the magnetic flux guide in the axial direction from the inside of the housing. The brake shaft is
A sleeve magnetic flux guide serving as the magnetic flux guide protrudes toward the inner peripheral portion of the sleeve, and has an outer peripheral portion that forms the seal gap with the inner peripheral portion, and the magnetic flux is guided to the outer peripheral portion through the seal gap. An axial flux guide,
Covering the outer peripheral portion of the axial magnetic flux guide from the inside of the housing to restrict the passage of magnetic flux from the outer peripheral portion to the inside of the housing, and the communication gap between the sleeve magnetic flux stopper and the sleeve magnetic flux stopper The fluid brake device according to claim 1, further comprising: an axial magnetic flux stopper that forms The magnetic seal sleeve further includes a permanent magnet that generates a magnetic flux guided from an inner peripheral portion of the magnetic flux guide on the inner side of the housing by a magnetic pole,
The fluid brake according to any one of claims 1 to 7, wherein the magnetic flux stopper covers an inner peripheral portion of the magnetic flux guide that guides the magnetic flux generated by the permanent magnet from the inside of the housing. apparatus. The magnetic flux guide is disposed on the inside of the housing of the permanent magnet,
The magnetic flux stopper is exposed to the fluid chamber on the inner side of the housing to give the communication gap a width equal to or smaller than the seal gap in the entire area between the fluid chamber and the seal gap. The fluid brake device according to claim 8. The magnetic flux guide is disposed on the outer side of the casing of the permanent magnet, and has an inner peripheral portion that protrudes toward the inner peripheral side of the permanent magnet.
10. The fluid brake device according to claim 8, wherein the magnetic flux stopper is disposed on an inner peripheral side of the permanent magnet, and covers an inner peripheral portion of the magnetic flux guide from an inner side of the housing. The pair of magnetic flux guides arranged on the outer side and the inner side of the permanent magnet each have an inner peripheral portion that protrudes to the inner peripheral side from the permanent magnet,
The magnetic flux stopper is disposed on the inner peripheral side of the permanent magnet, covers the inner peripheral portion of the magnetic flux guide on the outer side of the casing from the inner side of the casing, and is arranged on the inner side of the magnetic flux guide on the inner side of the casing. The fluid brake device according to claim 10, wherein a peripheral portion is covered from the outside of the housing. The brake shaft is
Each sleeve magnetic flux guide as the magnetic flux guide protrudes toward the inner peripheral portion of each sleeve, thereby having an outer peripheral portion that forms the seal gap with the inner peripheral portion, and through the seal gap to the outer peripheral portion. A pair of axial flux guides through which the magnetic flux is guided;
The axial magnetic flux guide on the outer side of the casing is covered from the inner side of the casing, and the axial magnetic flux guide on the inner side of the casing is covered from the outer side of the casing. The fluid brake device according to claim 11, further comprising an axial magnetic flux stopper that restricts passage of magnetic flux to a side and forms the communication gap with a sleeve magnetic flux stopper as the magnetic flux stopper. The brake shaft has outer peripheral portions that form the seal gap with the inner peripheral portion by projecting toward the inner peripheral portion of the sleeve magnetic flux guide as each of the magnetic flux guides. Having a pair of axial flux guides through which the magnetic flux is guided through the seal gap;
The fluid brake device according to claim 11 or 12, wherein the sleeve magnetic flux stopper is inserted between the axial magnetic flux guides, and the communication gap is formed between the axial magnetic flux guides. 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 13,
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.

Images