JP2008051093A - Valve timing regulator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a valve timing regulator with high durability. <P>SOLUTION: This valve timing regulator 1 is provided with a rotor 130 imparted with a brake torque in response to viscosity of a magnetic viscous fluid 150, by contacting with the viscosity-variable magnetic viscous fluid 150, a solenoid coil 140 and an electrification control circuit 160 for controlling variably the viscosity of the magnetic viscous fluid 150, and a phase regulation mechanism 8 for regulating a relative phase between a crankshaft of an internal combustion engine and a cam shaft thereof, according to the brake torque input from the rotor 130. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a valve timing adjusting device for an internal combustion engine that adjusts the valve timing of at least one of an intake valve and an exhaust valve whose camshaft opens and closes by torque transmission from a crankshaft.

2. Description of the Related Art Conventionally, there is known a valve timing adjusting device that can adjust a relative phase (hereinafter referred to as “engine phase”) between a crankshaft and a camshaft that determines valve timing in accordance with a brake torque generated by a hysteresis brake. As a hysteresis brake used in such a valve timing adjusting device, a hysteresis member is arranged between a pair of magnetic field generating members, and a brake torque corresponding to the magnetic field between the magnetic field generating members is generated in the hysteresis member. For example, it is disclosed in Patent Document 1.
JP 2004-11537 A

  However, in the hysteresis brake configured as described above, an air gap for generating a magnetic field must be formed between the hysteresis member and the magnetic field generating member. Here, the hysteresis member generates heat due to hysteresis loss. However, since the air in the air gap functions as a heat insulating layer, it is difficult for heat to escape from the hysteresis member. Moreover, in the hysteresis brake used in the valve timing adjusting device, the brake torque is sequentially changed in accordance with the operation of the internal combustion engine, so that hysteresis loss that generates heat is generated almost continuously in the hysteresis member. . From these facts, the hysteresis member is likely to be at a high temperature, so that a decrease in durability is a problem.

  The present invention has been made in view of these problems, and an object thereof is to provide a highly durable valve timing adjusting device.

  According to the first aspect of the present invention, the brake torque input from the rotating body to the phase adjusting mechanism for adjusting the engine phase is applied to the rotating body when the rotating body contacts the functional fluid. Therefore, even if the rotating body generates heat due to the generation of brake torque, etc., it becomes possible to dissipate heat through the functional fluid, so that heat dissipation suppresses thermal deformation and thermal deterioration of the rotating body, thereby improving durability. be able to. Moreover, since the brake torque is applied to the rotating body in accordance with the viscosity of the functional fluid that is variably controlled by the viscosity control means, the engine phase according to the brake torque and thus the valve timing is adjusted with high accuracy by the viscosity control. be able to.

  Magneto-Rheological Fluid, which is a kind of functional fluid, has a large viscosity change rate with respect to an applied magnetic field. Therefore, according to the invention described in claim 2, since the viscosity control means variably controls the viscosity of the magnetorheological fluid by the magnetic field applied to the magnetorheological fluid as the functional fluid, a large brake is applied as the control value of the applied magnetic field increases. Torque can be generated. Therefore, since the contact area required for applying the desired brake torque by bringing the magnetorheological fluid into contact with the rotating body is small, the rotating body can be reduced in size.

  According to the invention described in claim 3, since the magnetorheological fluid is a functional fluid in which magnetic particles are suspended in oil, for example, oil having the same components as the lubricating oil of the internal combustion engine is employed as the base oil. Can give consideration to the global environment. The magnetorheological fluid may be one obtained by suspending magnetic particles in a liquid base material other than oil, or one obtained by mixing magnetic fluid (Magnetic Compound Fluid). .

  According to the fourth aspect of the present invention, since the energization control circuit in the viscosity control means controls the energization current to the solenoid coil that generates the magnetic field applied to the magnetorheological fluid, the applied magnetic field is uniquely defined for the energization current. Can be determined. Therefore, it is possible to accurately control the viscosity of the magnetorheological fluid by applying the magnetic field, and to improve the adjustment accuracy of the valve timing.

  According to the invention described in claim 5, the support body forms a magnetic gap in which the solenoid coil generates a magnetic field between the rotating body and the magnetic field is generated in a state in which the magnetic viscous fluid is interposed in the magnetic gap. It will be realized below. Here, since the shear stress of the magnetorheological fluid that generates the brake torque increases as the size of the space where the magnetorheological fluid exists, the shearing stress increases due to the magnetorheological fluid in the limited magnetic gap between the support and the rotating body. Thus, a large brake torque can be generated. In addition, since the heat generation of the rotating body is reduced by the heat dissipation action through the magnetorheological fluid, it is possible to suppress deformation and deterioration of the support body that rotatably supports the rotating body due to heat transfer from the rotating body.

  In the hysteresis brake as disclosed in Patent Document 1 described above, a magnetic field is generated in an air gap in which air having low permeability is interposed, and therefore the size of the air gap needs to be sufficiently small. Therefore, the manufacturing tolerances of the hysteresis member and the magnetic field generating member that form the air gap must be strictly controlled, and these members must be arranged accurately, making it difficult to increase productivity. . In addition, since the valve timing adjusting device is generally used in a vibration environment such as a vehicle, there is a problem that durability is lowered due to a collision between a hysteresis member sandwiching a small air gap and a magnetic field generating member. On the other hand, according to the invention described in claim 5, a magnetic field is generally generated in the magnetic gap under the condition that a magnetic viscous fluid having a high magnetic permeability and a large viscosity change rate with respect to the applied magnetic field is interposed in the magnetic gap. The size of the magnetic gap can be increased as much as possible. Accordingly, it is possible to reduce the required level regarding the manufacturing tolerance and the placement accuracy of the rotating body and the support body, and to prevent the deterioration of the durability due to the collision of the rotating body and the support body even when used in a vibration environment. be able to.

  According to the sixth aspect of the present invention, since one of the rotating body and the support is accommodated in the other and the magnetorheological fluid is sealed, the magnetorheological fluid is inserted into the magnetic gap between the rotor and the support. It becomes easy to interpose. Therefore, it is possible to suppress thermal deformation and thermal degradation by the magnetorheological fluid without requiring a special cooling mechanism, while suppressing a decrease in brake torque due to insufficient magnetorheological fluid in the magnetic gap.

  There is a possibility that the magnetorheological fluid leaks from the interface between the rotating body and the support. According to the seventh aspect of the present invention, at least one of the rotating body and the support body forms a magnetic pole along the interface between the rotating body and the support body. Can be attracted to the magnetic pole. Therefore, leakage of the magnetorheological fluid can be suppressed.

  According to the invention described in claim 8, since the rotating body is accommodated in the support body, the heat generated by the rotating body is transmitted to the support body through the magnetorheological fluid, and the transmitted heat is radiated from the support body to the outside. Can do. Further, since the rotating body accommodated in the support body is smaller than the support body, it is possible to reduce the rotation inertia of the rotating body and suppress the vibration due to the support backlash of the rotating body.

  According to the ninth aspect of the present invention, the rotating magnetic part housed inside the support in the rotating body, the supporting magnetic parts on both sides of the supporting body sandwiching the rotating magnetic part in the rotation axis direction, and the connection between the supporting magnetic parts are connected. All of the coil holding portions to be formed are made of a magnetic material. Therefore, according to the solenoid coil held by the coil holding part on the outer peripheral side of the rotating magnetic part, a magnetic field that allows the magnetic flux to pass through the magnetic gap between the rotating magnetic part and each supporting magnetic part can be reliably generated. That is, since a magnetic field can be generated in the magnetic gap on both sides in the rotation axis direction of the rotating magnetic part, the rotating magnetic part can be held at a normal position in the rotating axis direction by the generation of the magnetic field.

  According to the tenth aspect of the present invention, both the rotating magnetic part housed in the support body in the rotating body and the coil holding part for holding the solenoid coil in the support body are formed of a magnetic material. Therefore, according to the solenoid coil held by the coil holding part at a position facing the rotating magnetic part across the magnetic gap, the magnetic field through which the magnetic flux passes through the magnetic gap between the rotating magnetic part and the coil holding part. Can be reliably generated.

  In the support body of the invention according to claim 10, the portion located on the opposite side of the coil holding portion with the rotating magnetic portion housed in the inside thereof in the direction of the rotation axis is, for example, between the rotating magnetic portion and the coil holding portion. It can be set as the structure which does not contribute substantially to the magnetic field generation | occurrence | production in a magnetic gap. Therefore, as in the invention described in claim 11, for the heat radiating part of the support body provided on the opposite side of the solenoid coil with the rotating magnetic part sandwiched in the rotation axis direction, for example, heat inside the support body is radiated to the outside. As a configuration suitable for this, the heat radiation action from the rotating magnetic part inside the support can be enhanced.

  The magnetorheological fluid in the state of being interposed in the magnetic gap can apply brake torque to the rotating body by the base viscosity of the fluid itself even when no magnetic field is generated in the magnetic gap. Here, since the base viscosity of the magnetorheological fluid usually increases as the environmental temperature decreases, for example, in a low temperature environment, the brake torque may increase due to the increase in base viscosity, and the valve timing may deviate from the target. There is. Therefore, according to the twelfth aspect of the invention, since the solenoid coil stops generating the magnetic field, the magnetorheological fluid is discharged from the magnetic gap to the fluid reservoir communicating therewith. To be isolated from the magnetic gap. Therefore, when the generation of the magnetic field is stopped, the brake torque applied to the rotating body by the magnetorheological fluid in the magnetic gap can be suppressed even in a low temperature environment. In addition, according to the twelfth aspect of the present invention, when the solenoid coil generates a magnetic field, the magnetorheological fluid is attracted from the fluid reservoir to the magnetic gap. Therefore, when a magnetic field is generated, a desired brake torque can be obtained by controlling the viscosity of the magnetorheological fluid from the generated magnetic field in a state where the magnetorheological fluid is reliably interposed in the magnetic gap. For these reasons, the target valve timing can be accurately realized both when the magnetic field is generated by the solenoid coil and when it is stopped.

  According to the thirteenth aspect of the present invention, since the support forms both a magnetic gap and a fluid reservoir with the internal rotary body, the magnetic gap can be easily provided only by arranging the rotary body inside the support. And a fluid clamp can be formed.

  According to the fourteenth aspect of the present invention, since the magnetorheological fluid is partially filled in the support body that accommodates the rotating body, the magnetic gap is formed between the magnetic gap and the fluid reservoir formed between the support body and the rotating body inside. It is possible to move the magnetorheological fluid with certainty.

  According to the fifteenth aspect of the present invention, since the support body forms a fluid reservoir vertically below the magnetic gap, when the magnetic field is stopped, the support from the magnetic gap to the fluid retainer is caused by the natural gravitational action. The discharge of the magnetorheological fluid can be promoted. Therefore, the configuration for discharging the magnetorheological fluid from the magnetic gap can be simplified.

  According to the sixteenth aspect of the present invention, since the support body forms a fluid reservoir outside the rotation radial direction of the rotating body with respect to the magnetic gap, the centrifugal force that inevitably occurs in the rotating body when the magnetic field is stopped is generated. The action of force can facilitate the discharge of the magnetorheological fluid from the magnetic gap to the fluid retainer. Therefore, the configuration for discharging the magnetorheological fluid from the magnetic gap can be simplified. The fluid reservoir on the outer side in the radial direction of the magnetic gap may be formed in an annular shape extending along the rotational direction of the rotating body as in the invention described in claim 17, for example. A plurality of them may be formed along the rotating direction of the rotating body as in the present invention.

  According to the nineteenth aspect of the present invention, since the support body forms a magnetic pole around the fluid reservoir, while the solenoid coil stops generating the magnetic field, the magnetorheological fluid is attracted to the fluid reservoir so that the magnetorheological fluid is magnetized. Returning to the gap can be prevented.

  According to the twentieth aspect, the strength of the magnetic field generated by the magnetic pole around the fluid reservoir at the communication point between the magnetic gap and the fluid reservoir is lower than the strength of the magnetic field generated by the solenoid coil at the communication point. Therefore, while the solenoid coil stops generating the magnetic field, the magnetorheological fluid is sufficiently attracted and trapped in the fluid reservoir, and conversely, when the solenoid coil generates the magnetic field, the magnetorheological fluid is caused to reach the magnetic gap by the generated magnetic field. Suction can be reliably performed. Therefore, the target valve timing can be more accurately realized both when the magnetic field is generated by the solenoid coil and when it is stopped.

  According to the twenty-first aspect of the present invention, the width changing portion of the magnetic gap becomes wider in the direction of the gap through which the magnetic flux generated by the solenoid coil passes the closer to the fluid reservoir. According to such a width changing portion, the magnetorheological fluid whose viscosity has been increased by the magnetic field generated by the solenoid coil is clogged in the vicinity of the fluid reservoir of the magnetic gap, and the magnetorheological fluid is unlikely to reach the location away from the fluid reservoir of the magnetic gap. Can be prevented.

  According to the twenty-second aspect of the present invention, since the rotation taper portion of the rotating body faces the support body in the direction of the rotation axis across the width change portion of the magnetic gap, the rotation axis direction substantially coincides with the gap direction of the magnetic gap. . Therefore, it is possible to easily obtain the above widened shape simply by disposing the rotating body inside the support for the width changing portion between the rotating taper portion and the support that is separated from the support toward the outer side in the rotational radial direction. it can.

  According to the twenty-third aspect of the present invention, the support taper portion of the support body faces the rotating body in the direction of the rotation axis across the width change portion of the magnetic gap, and therefore the rotation axis direction substantially coincides with the gap direction of the magnetic gap. . Therefore, with respect to the width change portion between the support taper portion and the rotating body that is separated from the rotating body as it goes outward in the rotational radial direction, the above widened shape can be easily obtained simply by arranging the rotating body inside the support body. it can.

  According to the twenty-fourth aspect of the present invention, an electro-rheological fluid that is a kind of functional fluid has a high viscosity change rate with respect to an applied electric field. Therefore, according to the invention of claim 24, the viscosity control means variably controls the viscosity of the electrorheological fluid by the electric field applied to the electrorheological fluid as the functional fluid. The brake torque can be changed quickly. Therefore, the adjustment response of the valve timing is increased. The electrorheological fluid may be one in which dielectric particles are suspended in a liquid base material (dispersion system), or one consisting of a single dielectric fluid (homogeneous system). Also good.

  According to the invention of claim 25, in the viscosity control means, the energization control circuit controls the energization voltage to the plurality of electrodes that generate the applied electric field to the electrorheological fluid. Can be determined. Therefore, the adjustment accuracy of the valve timing can be improved by accurately controlling the viscosity of the electrorheological fluid by applying the electric field.

  According to the invention of claim 26, the support forms an electrical gap between the rotating body and the electrode that generates an electric field, and the electric field is generated by the electrorheological fluid being interposed in the electrical gap. It will be realized under the condition. Here, since the shear stress of the electrorheological fluid that generates the brake torque increases as the size of the space in which the electrorheological fluid exists, the electrorheological fluid in the limited electrical gap between the support and the rotating body is increased. According to this, a large brake torque can be generated. In addition, since the heat generation of the rotating body is reduced by the heat dissipation action through the electrorheological fluid, it is possible to suppress the support body that rotatably supports the rotating body from being deformed and deteriorated by heat transfer from the rotating body.

  According to the twenty-seventh aspect of the present invention, since one of the rotating body and the support is accommodated in the other and the electrorheological fluid is sealed, the electric viscosity is set in the electric gap between the rotating body and the support. It becomes easy to interpose fluid. Therefore, it is possible to suppress thermal deformation and thermal deterioration by the electrorheological fluid without requiring a special cooling mechanism, while suppressing a decrease in brake torque due to insufficient electrorheological fluid in the electric gap.

  Generally, a low-viscosity electrorheological fluid is likely to leak out from the interface between the rotating body and the support. Therefore, according to the invention as set forth in claim 28, since the seal member seals the interface between the rotating body and the support body, it is possible to stop the electrorheological fluid from leaking out from the interface.

  According to the inventions of claims 29 and 32, since the rotating body is accommodated inside the support body, the heat generated by the rotating body is transmitted to the support body through the electrorheological fluid, and the transmitted heat is radiated from the support body to the outside. can do. Further, since the rotating body accommodated in the support body is smaller than the support body, it is possible to reduce the rotation inertia of the rotating body and suppress the vibration due to the support backlash of the rotating body.

  According to the invention of claim 30, the electrode holding portion of the support body is arranged so that the positive and negative electrodes as the electrodes are arranged in the rotational radial direction of the rotating body at a position facing the rotating body with respect to the rotating shaft direction across the electrical gap. Since they are held alternately, an electric field can be generated in a wide range in the rotational radius direction. Therefore, the physique required to obtain a desired brake torque can be reduced. Further, when both the positive and negative electrodes are held on the support that supports the rotating body, the interface between the rotating body and the support is different from the case where the positive and negative electrodes are respectively distributed to the rotating body and the support. Since it is not necessary to provide an electrical insulating material for preventing discharge, the configuration can be simplified.

  According to the invention of claim 31, since one of the rotating body and the support is accommodated in the other and the electrorheological fluid is completely filled, the electric gap between the rotating body and the support is electrically charged. A viscous fluid can always be interposed. Therefore, it is possible to suppress thermal deformation and thermal degradation by the electrorheological fluid without requiring a special cooling mechanism, while suppressing a decrease in brake torque due to lack of electrorheological fluid in the electric gap, In addition, discharge between the positive and negative electrodes is less likely to occur.

  According to the thirty-second aspect of the present invention, the electrode holding portions of the support that holds the positive and negative electrodes are provided on both sides of the support inside the rotating body in the direction of the rotation axis, and each of the electrodes is electrically connected to the rotating body. A gap is formed. According to this, since the brake torque can be applied to the rotating body from both sides in the rotation axis direction, the brake torque increases.

  In the inside of a support partially filled with a magnetorheological fluid as in the invention described in claim 33, when the pressure in the inside increases or decreases due to expansion or contraction of air due to a change in environmental temperature, the support or the rotating body is deformed. There is a concern that the durability may be reduced by inviting the above. However, according to the invention described in claim 33, the vent hole formed by at least one of the support and the shaft portion of the rotating body that passes through the support and is connected to the phase adjustment mechanism is provided on the support body with which it communicates. The inside and outside of the air can be taken in and out according to the expansion and contraction of the air due to the environmental temperature change. According to this, it is possible to suppress a situation in which durability is lowered due to deformation of the support or the rotating body due to increase or decrease of the pressure inside the support.

  According to the thirty-fourth aspect of the present invention, the rolling bearing of the support body which is exposed inside the support body partially filled with the magnetorheological fluid and supports the shaft portion of the rotating body has an increased pressure inside the support body. There is concern about the intrusion of magnetorheological fluid. However, the function of the air holes makes it difficult for the pressure inside the support to change, so that it is possible to suppress a situation in which the durability of the rolling bearing is reduced due to the penetration of the magnetorheological fluid.

  In the rolling bearing exposed in the inside of the support body as in the 35th aspect of the invention, there is a concern that the lubricating liquid sealed therein leaks out due to a decrease in pressure inside the support body. However, the function of the air holes makes it difficult for the pressure inside the support to change, so that it is possible to suppress a situation where the durability of the rolling bearing is lowered due to leakage of the lubricating liquid.

  The sealing member that seals between the shaft portion of the support and the rotating body as in the invention described in claim 36 needs to increase the contact pressure with respect to the shaft portion as the pressure inside the support increases. Here, when the contact pressure of the seal member with respect to the shaft portion increases, there is a possibility that the valve timing is shifted due to the brake torque caused by the contact pressure acting on the shaft portion in a state where no magnetic field is generated in the magnetic gap. . However, according to the function of the vent hole, an increase in pressure inside the support can be suppressed, and the contact pressure of the seal member on the shaft portion can be reduced as much as possible. According to this, the brake torque which acts on the shaft portion due to the contact pressure of the seal member can be reduced.

  According to the invention of claim 37, since the end portion of the air hole exposed inside the support body is located above the liquid surface of the magnetorheological fluid in the stopped state of the rotating body, It becomes difficult for the magnetorheological fluid inside the support to flow into the end portion. According to this, the situation where the magnetorheological fluid flows out from the inside of the support body to the outside of the support body through the vent hole can be suppressed.

  According to the thirty-eighth aspect of the invention, the end of the vent hole exposed inside the support is provided with a filter that allows passage of gas and rejects passage of liquid. Of the magnetorheological fluid can be prevented. According to this, the situation where the magnetorheological fluid flows out from the inside of the support body to the outside of the support body through the vent hole can be avoided.

  According to the invention of claim 39, the air hole formed in the shaft portion of the rotating body communicates between the inside of the support body and the inside of the phase adjustment mechanism that is the outside of the support body. Difficult to get in. Accordingly, it is possible to avoid a situation in which durability is reduced due to the foreign matter being obstructed by the introduction and removal of air through the vent hole.

  According to the invention of claim 40, the shaft portion of the rotating body has a cylindrical shape in which the vent hole penetrates in the rotation axis direction and the end portion of the vent hole opens on the exposed end surface to the inside of the support body. Formation becomes easy.

  According to the invention of claim 41, a filter that allows passage of gas and rejects passage of liquid is provided at an end portion of a vent hole that opens to an exposed end surface inside the support body in the shaft portion of the rotating body. Therefore, the magnetorheological fluid inside the support can be prevented from flowing into the end portion. According to this, the situation where the magnetorheological fluid flows out from the inside of the support body to the outside of the support body through the vent hole can be avoided. In addition, since the end of the vent hole in which the filter is provided opens to the end surface of the rotating rotating body, the magnetorheological fluid adhering to the filter is blown off by the rotating centrifugal force of the shaft, and the filter of the magnetorheological fluid is filtered. Deterioration can be suppressed. Furthermore, since the filter is provided at the end of the vent hole that opens to the end surface of the shaft portion exposed inside the support and is protected by the support, the filter may be damaged due to the collision of foreign matter outside the support. Can be prevented.

  According to the invention of claim 42, since the shaft portion of the rotating body is cantilevered by the support body on the side connected to the phase adjusting mechanism rather than the end face where the vent hole is opened, the end face is securely provided inside the support body. It is possible to secure an air inlet / outlet port by exposing to air.

  According to the invention of claim 43, since an enlarged gap whose width in the gap direction is larger than that of the magnetic gap is formed between the rotating body and the support body, by flowing a magnetorheological fluid into the enlarged gap, The magnetorheological fluid inside the support can be increased as much as possible within the range of partial filling. According to this, the amount of thermal energy that can be absorbed by the magnetorheological fluid inside the support can be increased, and deterioration of the magnetorheological fluid can be suppressed.

  According to the invention of claim 44, the rolling bearing exposed to the enlarged gap and supporting the shaft portion of the rotating body is separated from the magnetic gap in which the solenoid coil generates a magnetic field. The situation where the viscous fluid is induced and enters the rolling bearing can be suppressed.

  According to the invention described in claim 45, the magnetorheological fluid is increased from the enlarged gap into the parting hole of the rotating body where the enlarged gap is formed, thereby increasing the effect of increasing the magnetorheological fluid in the support. be able to. Further, the presence of the lightening hole can reduce the rotational inertia of the rotating body, thereby improving the responsiveness of the rotating body, and hence the valve timing adjustment responsiveness.

  Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
1 to 3 show a valve timing adjusting device 1 according to a first embodiment of the present invention. The valve timing adjusting device 1 is mounted on a vehicle and provided in a transmission system that transmits engine torque from a crankshaft (not shown) of an internal combustion engine to a camshaft 2. The valve timing adjusting device 1 is a combination of the brake system 4 and the phase adjusting mechanism 8 and the like, and sequentially realizes valve timing suitable for the internal combustion engine by adjusting the engine phase. In the present embodiment, the camshaft 2 opens and closes an intake valve (not shown) of the internal combustion engine, and the valve timing adjusting device 1 adjusts the valve timing of the intake valve.

  First, the brake system 4 will be described. As shown in FIG. 1, the brake system 4 includes a fluid brake 100 and an energization control circuit 160. The fluid brake 100 generates a brake torque to be applied to the rotating body 130 accommodated in the support 110 by the magnetorheological fluid 150 enclosed in the support 110. The fluid brake 100 is provided with a solenoid coil 140 that applies a magnetic field in accordance with the energization current to the magnetorheological fluid 150 in the support 110, and the apparent viscosity of the magnetorheological fluid 150 changes due to the applied magnetic field, Accordingly, the applied brake torque to the rotating body 130 changes. The energization control circuit 160 is composed of a microcomputer or the like, and is disposed outside the fluid brake 100 and is electrically connected to the solenoid coil 140. The energization control circuit 160 controls the energization current to the solenoid coil 140 during operation of the internal combustion engine. Under this control, the fluid brake 100 variably controls the viscosity of the magnetorheological fluid 150 to maintain or increase or decrease the applied brake torque to the rotating body 130.

  Next, the phase adjustment mechanism 8 will be described. The phase adjusting mechanism 8 includes a driving side rotating body 10, a driven side rotating body 20, a biasing member 30, a planet carrier 40, and a planetary gear 50.

  As shown in FIG. 1, the drive-side rotating body 10 is formed by screwing a gear member 12 and a sprocket 13 that are both formed in a cylindrical shape on the same axis. An inner peripheral portion of the gear member 12 forms a drive side internal gear portion 14. The sprocket 13 is provided with a plurality of teeth 16 that protrude outward in the radial direction. The sprocket 13 is connected to the crankshaft by winding an annular timing chain between the teeth 16 and the plurality of teeth of the crankshaft. Therefore, when the engine torque output from the crankshaft is input to the sprocket 13 through the timing chain, the drive-side rotator 10 rotates while maintaining a relative phase with respect to the crankshaft in conjunction with the crankshaft. At this time, the rotation direction of the drive side rotator 10 is the counterclockwise direction of FIGS.

  As shown in FIGS. 1 and 3, the driven-side rotator 20 is formed in a bottomed cylindrical shape and is concentrically disposed on the inner peripheral side of the sprocket 13. The peripheral wall portion of the driven side rotating body 20 forms a driven side internal gear portion 22. The number of teeth of the driven side internal gear portion 22 is set to be larger than the number of teeth of the driving side internal gear portion 14 (see FIG. 2). The driven-side internal gear portion 22 is fitted to the inner peripheral side of the sprocket 13 in a form adjacent to the drive-side internal gear portion 14 while being displaced in the rotational axis direction.

  As shown in FIG. 1, the bottom wall portion of the driven-side rotator 20 forms a connecting portion 24 that is connected to the camshaft 2 by being coaxially bolted and connected. With this connection, the driven-side rotator 20 can rotate while maintaining a relative phase with respect to the camshaft 2 in conjunction with the camshaft 2 and can rotate relative to the drive-side rotator 10. . The relative rotational direction in which the driven-side rotator 20 advances with respect to the drive-side rotator 10 is the direction X in FIGS. 2 and 3, and the driven-side rotator 20 is retarded with respect to the drive-side rotator 10. The relative rotation direction is the direction Y in FIGS.

  As shown in FIG. 1, the urging member 30 is formed of a torsion coil spring and is disposed concentrically on the inner peripheral side of the sprocket 13. One end 31 of the biasing member 30 is locked by the sprocket 13, and the other end 32 of the biasing member 30 is locked by the connecting portion 24. The urging member 30 urges the driven-side rotator 20 toward the retard side with respect to the drive-side rotator 10 (that is, the direction Y in FIGS. 2 and 3) by these connections.

  As shown in FIGS. 1 to 3, the planetary carrier 40 is formed in a cylindrical shape, and an input portion 41 to which brake torque is input from the rotating body 130 of the fluid brake 100 is formed by the inner peripheral portion. A plurality of grooves 42 are opened in the input portion 41 concentric with the rotating bodies 10, 20 and the rotating body 130, and the planetary carrier 40 is connected to the rotating body 130 via a joint 43 fitted to the grooves 42. It is connected to the shaft part 131. By this connection, the planetary carrier 40 can rotate integrally with the rotating body 130 and can rotate relative to the driving-side rotating body 10.

  The planetary carrier 40 has an eccentric portion 44 that is eccentric with respect to the gear portions 14 and 22 formed by the outer peripheral portion. The eccentric portion 44 is fitted on the inner peripheral side of the center hole portion 51 of the planetary gear 50 via a bearing 45. By this fitting, the planetary gear 50 can realize a planetary motion that revolves around the eccentric center of the eccentric portion 44 and revolves in the rotation direction of the eccentric portion 44.

  The planetary gear 50 is formed in a two-stepped cylindrical shape and is concentrically arranged with respect to the eccentric portion 44. That is, the planetary gear 50 is arranged eccentrically with respect to the gear portions 14 and 22. In the planetary gear 50, a driving-side external gear portion 52 and a driven-side external gear portion 54 are formed by a small diameter portion and a large diameter portion, respectively. The number of teeth of the driving side external gear portion 52 is set to be a predetermined number N less than the number of teeth of the driving side internal gear portion 14, and the number of teeth of the driven side external gear portion 54 is a predetermined number N than that of the driven side internal gear portion 22. Less is set. Therefore, the number of teeth of the driven side external gear part 54 is larger than the number of teeth of the driving side external gear part 52. 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 gear portion 14, and the driven-side external gear portion 54 is on the inner peripheral side of the driven-side internal gear portion 22. It is arranged and meshes with the gear part 22.

  With the above configuration, the differential gear portion 60 is formed that transmits the planetary carrier 40 by decelerating and transmitting the rotation of the planetary carrier 40 to the camshaft 2 by the planetary gear 50 meshing with the gear portions 14 and 22 performing planetary motion. The phase adjusting mechanism 8 including the differential gear portion 60 includes the brake torque applied to the planet carrier 40, the bias torque of the bias member 30 transmitted to the planet carrier 40 through the differential gear portion 60, and the cam shaft. The phase adjustment operation is performed in accordance with the magnitude relationship between the fluctuation torque of 2 and the average torque. The fluctuation torque of the camshaft 2 is a torque transmitted to the phase adjusting mechanism 8 as the internal combustion engine is operated, and the driven-side rotator 20 is driven by the average torque in the present embodiment. Is urged toward the retarded side (ie, the direction Y in FIGS. 2 and 3).

  Specifically, as the phase adjustment operation, when the planetary carrier 40 does not rotate relative to the drive-side rotator 10 due to maintenance of brake torque applied to the rotator 130, the planetary gear 50 is connected to the gear parts 14 and 22. It rotates integrally with the rotating bodies 10 and 20 while maintaining the meshing position. Therefore, the engine phase does not change, and as a result, the valve timing is kept constant.

  When the planetary carrier 40 rotates relative to the drive-side rotator 10 in the direction Y due to an increase in brake torque applied to the rotator 130, the planetary gear 50 changes the meshing position with the gear portions 14 and 22. Due to the planetary motion, the driven side rotator 20 rotates relative to the drive side rotator 10 in the direction X. Therefore, the engine phase changes to the advance side, and as a result, the valve timing advances.

  When the planetary carrier 40 rotates relative to the drive-side rotator 10 in the direction X due to a decrease in brake torque applied to the rotator 130, the planetary gear 50 changes the meshing position with the gear portions 14 and 22. Due to the planetary motion, the driven-side rotator 20 rotates relative to the drive-side rotator 10 in the direction Y. Therefore, the engine phase changes to the retard side, and as a result, the valve timing is retarded.

  Next, the characteristic part of the brake system 4 will be described in detail. As shown in FIG. 4, the rotating body 130 has a shaft portion 131 and a rotor portion 132. In this embodiment, the shaft portion 131 and the rotor portion 132 are integrally formed of a ferromagnetic material such as iron. For example, the shaft portion 131 and the rotor portion 132 are separated and at least the rotor portion 132 is included. May be formed of a ferromagnetic material. The shaft portion 131 has a shaft shape, and is connected to the input portion 41 (see FIG. 1) of the phase adjustment mechanism 8 at one end thereof. The rotor part 132 has an annular plate shape and is provided concentrically on the outer peripheral side of the axially intermediate part of the shaft part 131. The outer peripheral part 134 of the rotor part 132 is formed thicker than the inner peripheral side.

  The support 110 includes a fixed member 111, a cover member 112, and bearings 113 and 114, and has a hollow shape as a whole. In the present embodiment, both the fixing member 111 and the cover member 112 are formed of a ferromagnetic material such as iron. The fixing member 111 is fixed to an internal combustion engine that is a fixing node via a stay (not shown). The fixing member 111 is formed in a cup shape, and the shaft portion 131 passes through the bottom wall portion 115 thereof. A bearing 113 is provided on the bottom wall 115 of the fixing member 111. The bearing 113 rotatably supports the shaft portion 131 on the phase adjustment mechanism 8 side with respect to the rotor portion 132. The cover member 112 is formed in a cup shape, and the peripheral wall portion 116 thereof is liquid-tightly joined to the peripheral wall portion 117 of the fixing member 111. As a result, the peripheral wall portion 116 of the cover member 112 has a shape in which the bottom wall portion 115 of the fixing member 111 and the bottom wall portion 118 of the cover member 112 are connected. The peripheral wall 116 of the cover member 112 holds the solenoid coil 140 by its inner peripheral surface. A bearing 114 is provided on the bottom wall portion 118 of the cover member 112. The bearing 114 rotatably supports the shaft portion 131 on the side opposite to the phase adjustment mechanism 8 with the rotor portion 132 interposed therebetween.

  With the above configuration, the rotor portion 132 is accommodated in the internal space 119 of the support 110, and the outer peripheral portion 134 of the rotor portion 132 and the bottom walls on both sides of the members 111 and 112 sandwiching the outer peripheral portion 134 in the rotation axis direction. Magnetic gaps 120 and 121 are formed between the portions 115 and 118. Here, the magnetic gap 120 is a portion of the internal space 119 sandwiched between one end surface of the outer peripheral portion 134 of the rotor portion 132 and the inner surface of the bottom wall portion 115 of the fixing member 111. The magnetic gap 121 is a portion of the internal space 119 sandwiched between the other end surface of the outer peripheral portion 134 of the rotor portion 132 and the inner surface of the bottom wall portion 118 of the cover member 112. The gap directions of the magnetic gaps 120 and 121 substantially coincide with the rotation axis direction of the rotor portion 132, and the widths of the magnetic gaps 120 and 121 in the gap direction are constant.

  A magnetorheological fluid 150 is sealed in the internal space 119 of the support 110 in a completely filled state. Accordingly, the magnetic viscous fluid 150 is always interposed in the magnetic gaps 120 and 121 formed between the support 110 and the rotating body 130. Here, the magnetorheological fluid 150 is a kind of “functional fluid”, and is formed by suspending magnetic particles in a liquid base material. As the base material of the magnetorheological fluid 150, for example, 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. In general, since the lubricating oil is a component that is friendly to the global environment, the use of the same type of oil as that can contribute to the suppression of environmental pollution. As magnetic particles of the magnetorheological fluid 150, for example, a powdery magnetic material such as carbonyl iron is used. In the magnetorheological fluid 150 having such a component structure, the apparent viscosity increases as shown in FIG. 5 following the strength of the applied magnetic field, and is proportional to the viscosity and the size of the space where the magnetorheological fluid 150 exists. The characteristic that the shear stress increases in inverse proportion to the above appears.

  As shown in FIG. 4, the solenoid coil 140 is concentrically held on the outer peripheral side of the rotor portion 132 by the peripheral wall portion 116 of the cover member 112. When the solenoid coil 140 having such a holding configuration is energized, the magnetic flux passes through the fixing member 111, the magnetic gap 120, the outer peripheral portion 134 of the rotor portion 132, the magnetic gap 121, and the cover member 112 in order as indicated by the broken line arrows in FIG. In addition, a magnetic field is generated. As a result, since the magnetic field generated by the solenoid coil 140 is applied to the magnetorheological fluid 150 in the magnetic gaps 120 and 121, the magnetorheological fluid 150 is in a viscosity state corresponding to the intensity of the generated magnetic field. Therefore, between the elements 110 and 132 facing each other with the magnetic gaps 120 and 121 interposed therebetween, a direction in which the rotor portion 132 is braked against the support 110 by a shear stress proportional to the fluid viscosity (for example, during operation of the internal combustion engine, FIG. Brake torque can be generated in the second and third directions Y). As described above, in the present embodiment, as shown in FIG. 6, the brake torque that changes following the energization current to the solenoid coil 140 can be applied to the rotating body 130.

  According to such a first embodiment, by controlling the energization current to the solenoid coil 140 by the energization control circuit 160, the brake torque in the rotating body 130 can be uniquely determined according to the correlation of FIG. Therefore, by precisely controlling the energization current to the solenoid coil 140, it is possible to improve the adjustment accuracy of the engine phase according to the brake torque, and thus the adjustment accuracy of the valve timing.

  In addition, according to the first embodiment, a magnetic field can be generated through the magnetic gaps 120 and 121 formed on both sides in the rotation axis direction of the rotor part 132 so that the magnetic flux passes in the gap direction as indicated by the broken line arrows in FIG. it can. Therefore, if the rotor part 132 and the support body 110 are magnetized along the magnetic flux of the generated magnetic field, the rotor part 132 is magnetically held at a normal position in the rotation axis direction. The width of the gaps 120 and 121 is stabilized regardless of vehicle vibration or the like. As a result, an error is less likely to occur in the shear stress of the magnetorheological fluid 150 that correlates with the width of the magnetic gaps 120 and 121, so that the target valve timing can be accurately achieved.

  Further, in the first embodiment, since the magnetorheological fluid 150 having a large viscosity change rate with respect to the applied magnetic field is used, both end surfaces of the outer peripheral portion 134 of the rotor portion 132 that contributes to generation of brake torque by contact with the magnetorheological fluid 150 are used. A large brake torque can be generated while reducing the area. In addition, since the shear stress of the magnetorheological fluid 150 is inversely proportional to the size of the space where the fluid 150 exists, a large brake torque can be generated even by the magnetorheological fluid 150 in the magnetic gaps 120 and 121 with limited width. it can. From these things, the physique of the fluid brake 100 required in order to obtain a desired brake torque can be made small.

  Furthermore, according to the first embodiment, a magnetorheological fluid 150 having higher heat conductivity than air is enclosed in the support body 110 in which the rotor part 132 is accommodated. Therefore, even if the rotor portion 132 generates heat due to generation of brake torque or the like, heat can be radiated from the support 110 to the outside via the magnetorheological fluid 150. Therefore, the durability of the fluid brake 100 can be improved by suppressing thermal deformation and thermal deterioration of the rotating body 130 having the rotor portion 132 and the support body 110 thereof. Moreover, such a function of suppressing thermal deformation and thermal degradation is realized by using the magnetorheological fluid 150 for generating the brake torque without using a special cooling mechanism, so that the fluid brake 100 is enlarged and complicated. Is not accompanied.

  In addition, according to the first embodiment, the magnetorheological fluid 150 naturally has a high permeability in addition to a large viscosity change rate with respect to the applied magnetic field. Therefore, the width of the magnetic gaps 120 and 121 through which the magnetorheological fluid 150 is interposed can be increased as long as a desired brake torque is obtained. Therefore, not only can the required level of manufacturing tolerances and placement accuracy of the support 110 and the rotating body 130 be reduced, but the support 110 and the rotating body 130 can be connected to the magnetic gap 120 even in a vibration environment of a vehicle. , 121 can be prevented from colliding with each other, and durability can be enhanced.

  In the first embodiment described so far, the solenoid coil 140 and the energization control circuit 160 collectively constitute a “viscosity control unit”, and the rotor portion 132 corresponds to a “rotational magnetic portion”. The bottom wall portions 115 and 118 of the cover member 112 correspond to “support magnetic portions”, and the peripheral wall portion 116 of the cover member 112 corresponds to “coil holding portions”.

(Second embodiment)
As shown in FIG. 7, the second embodiment of the present invention is a modification of the first embodiment. In the rotating body 200 of the second embodiment, the inner peripheral portion 204 of the rotor portion 202 made of a ferromagnetic material is magnetized in advance to form a magnetic pole. This magnetic pole is formed along the contact interface between the bearing 113 through which the shaft portion 131 penetrates in the support 110 and the inner peripheral portion 204 of the rotor portion 202. In FIG. 7, the magnetized portion 206 of the rotor portion 202 that forms the magnetic pole is schematically shown by shading.

  According to such a second embodiment, the magnetorheological fluid 150 entering the contact interface between the rotor unit 202 and the bearing 113 can be attracted by the magnetic pole of the magnetized unit 206 and trapped. According to this, it becomes difficult for the magnetorheological fluid 150 to leak from the contact interface between the rotor portion 202 and the bearing 113 through the contact interface between the shaft portion 131 and the bearing 113 to the outside. A situation where the magnetic viscous fluid 150 is reduced and the brake torque is reduced can be avoided.

  In the second embodiment described so far, the rotor unit 202 corresponds to a “rotational magnetic unit”.

(Third embodiment)
As shown in FIG. 8, the third embodiment of the present invention is a modification of the first embodiment. In the third embodiment, the rotor portion 252 of the rotating body 250 is formed in a ring plate shape having a constant thickness. The fixing member 261 of the support 260 is formed in an annular plate shape, and the peripheral wall portion 264 of the cover member 262 is joined in a liquid-tight manner to the outer peripheral edge portion thereof. The solenoid coil 140 is held by the inner wall portion 266 of the fixing member 261 that forms the inner space 268 of the support 110. In this embodiment, the solenoid coil 140 is concentrically embedded in the inner wall portion 266, and the inner surface of the inner wall portion 266 and one end surface of the solenoid coil 140 are substantially flush with each other. Thus, a magnetic gap 270 is formed between the inner surface of the inner wall portion 266 and one end surface of the solenoid coil 140 with one end surface of the rotor portion 252. Accordingly, the magnetic flux generated by the solenoid coil 140 passes through the fixing member 261, the magnetic gap 270, the rotor portion 252 and the magnetic gap 270 in this order as indicated by the broken line arrows in FIG. In the third embodiment, since the magnetic gap 270 forms a part of the internal space 268 of the support 260, the magnetorheological fluid 150 completely filled in the internal space 268 is always interposed in the magnetic gap 270. Become.

  According to such a third embodiment, the cover member having the bottom wall portion 269 on the opposite side of the fixing member 261 with the rotor portion 252 sandwiched in the rotation axis direction and the peripheral wall portion 264 on the outer peripheral side of the rotor portion 252. 262 can be configured not to substantially contribute to the generation of a magnetic field in the magnetic gap 270. In this case, for example, the cover member 262 is formed of a non-magnetic material or the like, or the cover member 262 is formed in a thin shape that is easily magnetically saturated by press molding, thereby reducing weight and cost.

  In the third embodiment described so far, the rotor portion 252 corresponds to a “rotating magnetic portion”. Further, as shown in FIG. 8, the inner wall portion 266 of the fixing member 261 has a shape in which the solenoid coil 140 is held at a location facing the rotor portion 252 in the rotation axis direction with the magnetic gap 270 interposed therebetween. 266 corresponds to the “coil holder”.

(Fourth embodiment)
As shown in FIGS. 9 and 10, the fourth embodiment of the present invention is a modification of the third embodiment. In the third embodiment, the cover member 302 of the support body 300 is formed of a nonmagnetic material such as aluminum and has a plurality of heat radiation fins 304. Each radiating fin 304 has a flat plate shape that protrudes outward from the bottom wall portion 306 of the cover member 302 and is provided in parallel to each other at equal intervals.

  According to the fourth embodiment, heat transmitted from the rotating body 250 inside the support 300 to the bottom wall portion 306 of the cover member 302 through the magnetorheological fluid 150 is radiated from the plurality of radiating fins 304 to the outside. Can do. Here, according to the plurality of heat dissipating fins 304, the air cooling effect of the cover member 302 is enhanced, so that the amount of heat dissipated to the outside can be increased to further improve the durability.

  In the fourth embodiment described so far, the bottom wall portion 306 and the heat radiation fins 304 of the cover member 302 correspond to “heat radiation portions”.

(Fifth embodiment)
As shown in FIGS. 11 and 12, the fifth embodiment of the present invention is a modification of the third embodiment. In the fifth embodiment, the outer peripheral portion 354 of the rotor portion 352 of the rotating body 350 is formed so as to be thinner than a flat plate portion on the inner peripheral side and gradually become thinner toward the outer side in the rotational radial direction. As a result, the outer peripheral portion 354 of the rotor portion 352 has a tapered shape that gradually separates from the inner wall portion 362 of the fixing member 361 of the support 360 as it goes outward in the rotational radial direction. An outer peripheral portion 364 on the inner wall portion 362 of the fixing member 361 on the outer peripheral side of the holding portion of the solenoid coil 140 faces the outer peripheral portion 354 of the rotor portion 352 in the rotation axis direction. The outer peripheral portion 364 of the fixing member 361 is formed so as to gradually become thicker toward the outer side in the rotational radial direction. Thus, the outer peripheral portion 364 of the fixing member 361 has a taper that gradually separates from the rotor portion 352 of the rotating body 350 as it goes outward in the rotational radial direction. Here, the outer peripheral portion 364 of the fixing member 361 is formed such that its taper angle is larger than the taper angle of the outer peripheral portion 354 of the rotor portion 352.

  Thus, the magnetic gap 370 formed between the one end surface of the rotor portion 352 and the inner surface of the inner wall portion 362 of the fixing member 361 and the one end surface of the solenoid coil 140 is the outer peripheral portion 354 of the rotor portion 352 and the fixing member 361. In a portion sandwiched between 364, a width changing portion 372 is formed that widens in the gap direction toward the outer side in the rotational radial direction. Here, in the magnetic gap 370, the width changing portion 372 is formed in an annular shape along the rotation direction of the rotor portion 352, and further, a constant width portion 374 having a constant width in the gap direction is formed on the inner peripheral side thereof. . Accordingly, the magnetic flux generated by the solenoid coil 140 passes through the fixing member 361, the constant width portion 374 of the magnetic gap 370, the rotor portion 352, and the width changing portion 372 of the magnetic gap 370 in order as indicated by the broken line arrows in FIG. To be.

  As shown in FIGS. 11 and 12, the bottom wall portion 366 of the cover member 365 of the support 360 has a groove portion 367 at a location facing the outer peripheral portion 364 of the fixing member 361 in the axial direction on the outer peripheral side of the rotor portion 352. ing. The groove portion 367 is formed in an annular shape extending along the rotation direction of the rotor portion 352 and opens on the inner surface of the bottom wall portion 366 of the cover member 365. As a result, the groove portion 367 cooperates with the peripheral wall portion 368 of the cover member 365 and the outer peripheral portion 364 of the fixing member 361 so that the fluid reservoir 376 communicating with the width changing portion 372 of the magnetic gap 370 is outside the rotor portion 352 in the radial direction. Is formed. Here, the fluid reservoir 376 forms a part of the internal space 369 of the support 360 together with the magnetic gap 370, and has a larger volume than the width changing portion 372 as an annular space along the rotation direction of the rotor portion 352. Yes. In particular, in this embodiment, the magnetorheological fluid 150 is sealed in the interior space 369 of the support 360 in a partially filled state, and the magnetorheological fluid 150 is movable between the magnetic gap 370 and the fluid reservoir 376. .

  Therefore, hereinafter, the movement of the magnetorheological fluid 150 between the magnetic gap 370 and the fluid reservoir 376 will be described in detail with reference to FIG. Note that the vertical direction in FIG. 13 substantially matches the actual vertical direction.

  When the solenoid coil 140 generates a magnetic field by energization with the magnetorheological fluid 150 trapped in the fluid reservoir 376 as shown in FIG. 13B, the magnetic gap 370 is moved in the gap direction as shown in FIG. The rotor portion 352 and the fixing member 361 are magnetized along the magnetic flux passing therethrough. As a result, the magnetorheological fluid 150 in the fluid reservoir 376 is attracted to the magnetic gap 370 side between the rotor portion 352 and the fixed member 361, and the fluid 150 is attracted from the width changing portion 372 side as shown in FIG. Suctioned into 370. The magnetorheological fluid 150 sucked in this way has a viscosity corresponding to the generated magnetic field, so that brake torque can be applied to the rotor portion 352.

  When the solenoid coil 140 stops generating a magnetic field by stopping energization while the magnetorheological fluid 150 is attracted into the magnetic gap 370 as shown in FIG. 13A, the magnetization of the rotor portion 352 and the fixing member 361 It will be solved. As a result, the magnetorheological fluid 150 in the magnetic gap 370 is subjected to the action of gravity, and is dropped and discharged to a position below the magnetic gap 370 in the fluid reservoir 376 in the vertical direction. At this time, when the rotating body 350 rotates with the sprocket 13 (see FIG. 1) due to the operation of the internal combustion engine, the magnetorheological fluid 150 is lowered below the fluid reservoir 376 in the vertical direction by the action of centrifugal force. It is discharged to places other than the side. However, since the axial direction of the annular fluid reservoir 376 is substantially horizontal as shown in FIG. 13B, the fluid finally flows into the lower portion of the fluid reservoir 376 in the vertical direction. Since the magnetorheological fluid 150 discharged to the fluid reservoir 376 as described above is trapped in the fluid reservoir 376 and isolated from the magnetic gap 370 until the next magnetic field is generated, the brake torque is reduced by the base viscosity of the rotor. No part 352 is given.

  According to the fifth embodiment, only when the solenoid coil 140 stops generating the magnetic field, the generation of the brake torque can be restricted by isolating the magnetorheological fluid 150 from the magnetic gap 370. Therefore, even if the base viscosity of the magnetorheological fluid 150 increases as shown in FIG. 14 in a low temperature environment, the target valve timing is accurately realized by restricting the generation of the brake torque when the magnetic field generation is stopped. Can do. Further, the brake torque can be reduced to substantially zero, for example, by the regulation of its generation. Therefore, when the generation of the magnetic field is stopped, the driven-side rotator 20 can be quickly retarded with respect to the drive-side rotator 10 by the average torque of the urging torque of the urging member 30 and the fluctuation torque of the camshaft 2. Increases the lag response of the valve timing.

  Further, according to the fifth embodiment, when the generation of the magnetic field is stopped, the magnetorheological fluid 150 is discharged from the magnetic gap 270 to the fluid retainer 376 by using a natural gravity action or an inevitable centrifugal force action during the operation of the internal combustion engine. I am letting. Therefore, since it is not necessary to add a new device that promotes the discharging action of the magnetorheological fluid 150, the configuration can be simplified.

  Further, according to the fifth embodiment, the width changing portion 372 of the magnetic gap 370 is widened in the gap direction toward the outer side in the rotational radial direction of the rotor portion 352, that is, closer to the fluid reservoir 376. For this reason, in the width changing portion 372, the flow resistance at the time of suction of the magnetorheological fluid 150 becomes smaller as it approaches the fluid reservoir 376, and the strength of the magnetic field applied to the magnetorheological fluid 150 becomes weaker as it approaches the fluid reservoir 376. . According to such characteristics, it is possible to prevent the magnetorheological fluid 150 from increasing in viscosity due to the magnetic field and being clogged in the vicinity of the fluid reservoir 376 of the width changing portion 372. The fluid 150 can be distributed. Therefore, it is possible to avoid a situation in which the brake torque is reduced due to insufficient magnetorheological fluid 150 in the magnetic gap 370. In addition, since the strength of the magnetic field applied to the magnetorheological fluid 150 is increased at the location where the width changing portion 372 is separated from the fluid reservoir 376, a desired brake torque can be reliably generated. From these facts, the target valve timing can be accurately realized when the magnetic field is generated.

  Furthermore, according to the fifth embodiment, as shown in FIG. 11, the support 360 has a shape in which both a magnetic gap 370 and a fluid reservoir 376 are formed between the support 360 and the rotor portion 352 therein. According to this, the magnetic gap 370 and the fluid retaining 376 can be easily formed simply by disposing the rotor portion 352 inside the support 360, so that productivity is improved.

  In the fifth embodiment described so far, the rotor portion 352 corresponds to a “rotating magnetic portion”, and the outer peripheral portion 354 of the rotor portion 352 corresponds to a “rotating taper portion”. Further, the inner wall portion 362 of the fixing member 361 corresponds to a “coil holding portion”, and the outer peripheral portion 364 of the inner wall portion 362 of the fixing member 361 corresponds to a “support taper portion”.

(Sixth embodiment)
As shown in FIGS. 15 and 16, the sixth embodiment of the present invention is a modification of the fifth embodiment. In the sixth embodiment, the outer peripheral portion 404 of the fixing member 401 of the support body 400 is formed so that the taper angle thereof coincides with the taper angle of the outer peripheral portion 354 of the rotor portion 352 and faces the outer peripheral portion 354 in parallel. ing. As a result, the magnetic gap 410 formed between the one end surface of the rotor portion 352 and the inner surface of the inner wall portion 403 of the fixing member 401 and the one end surface of the solenoid coil 140 forms the outer peripheral portions 354 of the rotor portion 352 and the fixing member 401. A constant width portion 412 having a constant width in the gap direction and wider than the constant width portion 374 on the inner peripheral side is formed at a portion sandwiched between 404.

  Further, in the sixth embodiment, the bottom wall portion 406 of the cover member 405 of the support body 400 has a plurality of groove portions 407 at locations that face the outer peripheral portion 404 of the fixing member 401 on the outer peripheral side of the rotor portion 352 in the axial direction. ing. The groove portions 407 are arranged at equal intervals along the rotation direction of the rotor portion 352 and open to the inner surface of the bottom wall portion 406 of the cover member 405. In the present embodiment, each groove portion 407 has an arc shape along the rotation direction of the rotor portion 352, and has two portions in the vertical direction (substantially up and down direction in FIG. 16) and two in the horizontal direction (substantially left and right direction in FIG. 16). It is arranged at each location. As a result, each groove portion 407 cooperates with the peripheral wall portion 408 of the cover member 405 and the outer peripheral portion 404 of the fixing member 401 so that the fluid reservoir 416 communicated with the constant width portion 412 of the magnetic gap 410 in the rotational radial direction of the rotor portion 352. A plurality are formed on the outside. Here, each fluid reservoir 416 forms a part of the internal space 409 of the support body 400 together with the magnetic gap 410, and the total volume is larger than the volume of the constant width portion 412 as a plurality of spaces arranged in the rotation direction of the rotor portion 352. Is also set larger. Also in this embodiment, the magnetorheological fluid 150 is sealed in the interior space 409 of the support 400 in a partially filled state, and the magnetorheological fluid 150 can move between the magnet gap 410 and the fluid reservoirs 416. Yes.

  In the sixth embodiment, when the magnetorheological fluid 150 is trapped in each fluid reservoir 406 and the solenoid coil 140 generates a magnetic field as shown in FIG. Be attracted to. Therefore, the magnetorheological fluid 150 is attracted from the constant width portion 412 side into the magnetic gap 410 and has a viscosity corresponding to the generated magnetic field, so that brake torque is applied to the rotor portion 352.

  Further, when the solenoid coil 140 stops generating the magnetic field under the attracting state of the magnetorheological fluid 150 into the magnet gap 410, the magnetorheological fluid 150 is more vertical than the magnet gap 410 due to the action of gravity, as shown in FIG. It is discharged to the fluid reservoir 416 on the lower side in the direction. At this time, when the internal combustion engine is in operation, the magnetorheological fluid 150 is also discharged to fluid reservoirs 416 other than the vertically lower side by the action of centrifugal force. However, as shown in FIG. Outflow to the other fluid reservoir 416 is restricted by the both ends of the liquid. Thus, the magnetorheological fluid 150 discharged to each fluid reservoir 416 is trapped in each fluid reservoir 416 and isolated from the magnetic gap 410. That is, since the trap volume of the magnetorheological fluid 150 is increased, when the generation of the magnetic field is stopped, it is possible to sufficiently suppress the generation of the brake torque and to avoid the valve timing deviating from the target.

  In the sixth embodiment described so far, the inner wall portion 403 of the fixing member 401 corresponds to a “coil holding portion”, and the outer peripheral portion 404 of the inner wall portion 403 of the fixing member 401 corresponds to a “support taper portion”.

(Seventh embodiment)
As shown in FIGS. 17 and 18, the seventh embodiment of the present invention is a modification of the sixth embodiment. In the sixth embodiment, a permanent magnet 454 is embedded in the bottom wall portion 452 of the cover member 451 of the support body 450. The permanent magnet 454 is preliminarily magnetized with a ferromagnetic material. The permanent magnet 454 of the support 450 is formed in an annular shape having a smaller diameter than the groove 407 and is concentrically disposed on the inner peripheral side of the fluid reservoir 416. The permanent magnet 454 forms a magnetic pole on the outer peripheral surface side around the fluid reservoir 416. The strength of the magnetic field generated by the magnetic poles of the permanent magnet 454 at the communication location of the magnetic gap 410 and the fluid reservoir 416 is set to be weaker than the strength of the magnetic field generated by the solenoid coil 140 at the communication location. .

  In the seventh embodiment, the magnetorheological fluid 150 discharged to the fluid reservoirs 416 when the solenoid coil 140 stops generating the magnetic field is attracted to the magnetic poles of the permanent magnets 454 to enter the fluid reservoirs 416. It is surely trapped. Moreover, when the solenoid coil 140 generates a magnetic field, the magnetorheological fluid 150 can be reliably attracted to the magnetic gap 410 against the magnetic force of the permanent magnet 454 by setting the magnetic pole position and the magnetic field strength described above. According to the above, it is possible to suppress the generation of the brake torque when the generation of the magnetic field is stopped, and conversely generate the desired brake torque when the magnetic field is generated, thereby realizing more accurate valve timing adjustment.

(Eighth embodiment)
As shown in FIG. 19, the eighth embodiment of the present invention is a modification of the fifth embodiment. In the eighth embodiment, the cover member 501 of the support 500 is formed in a plate shape, and the inner wall portion 502 has a configuration similar to the bottom wall portion 366 of the cover member 365 of the fifth embodiment. The fixing member 503 is formed in a cup shape, and the peripheral wall portion 504 thereof is liquid-tightly joined to the outer peripheral edge portion of the cover member 501. The peripheral wall portion 504 of the fixing member 503 has a shape in which the bottom wall portion 505 of the fixing member 503 and the inner wall portion 502 of the cover member 501 are connected. The solenoid coil 140 is connected to the outer periphery of the rotor portion 352 by the inner peripheral surface thereof. Holding on the side. The bottom wall portion 505 opposite to the cover member 501 across the rotor portion 352 in the fixing member 503 is configured similarly to the inner wall portion 362 of the fixing member 361 of the fifth embodiment, except that the solenoid coil 140 is not embedded. have.

  With the above configuration, a magnetic gap 370 having a width changing portion 372 and a constant width portion 374 is formed between one end surface of the rotor portion 352 and the inner surface of the bottom wall portion 505 of the fixing member 503. In addition, a magnetic gap 510 having a constant width is formed between the other end surface of the rotor portion 352 and the inner surface of the inner wall portion 502 of the cover member 501. Furthermore, a fluid reservoir 376 communicating with the magnetic gaps 370 and 510 is formed by the joint of the groove portion 367 of the inner wall portion 502 of the cover member 501, the inner peripheral portion of the solenoid coil 140 and the outer peripheral portion 364 of the fixing member 503. Accordingly, the magnetic flux generated by the solenoid coil 140 passes through the fixing member 503, the magnetic gap 370, the rotor portion 352, the magnetic gap 510, and the cover member 501 in this order as indicated by the broken arrows in FIG.

  In the eighth embodiment, when the magnetic field is generated and stopped by the solenoid coil 140, the movement of the magnetorheological fluid 150 between the magnetic gap 370 and the fluid reservoir 376 forming the internal space 508 of the support 500 is the fifth. It occurs as in the embodiment. Also, the magnetic viscous fluid 150 moves between the magnetic gap 510 and the fluid reservoir 376 as the magnetic field of the solenoid coil 140 is generated and stopped. Therefore, when the magnetic field is generated, a desired brake torque is generated by the magnetorheological fluid 150 in the magnetic gaps 370 and 510, and conversely, the generation of the brake torque is suppressed when the generation of the magnetic field is stopped. Can be realized.

  In the eighth embodiment described so far, the inner wall portion 502 of the cover member 501 and the bottom wall portion 505 of the fixing member 503 correspond to “support magnetic portions”, respectively, and the peripheral wall portion 504 of the fixing member 503 is “coil holding”. Part.

(Ninth embodiment)
As shown in FIG. 20, the ninth embodiment of the present invention is a modification of the first embodiment. In the ninth embodiment, the solenoid coil 140 is not provided, but a pair of electrode plates 600 and 601 is provided instead. The electrode plates 600 and 601 are respectively embedded in the bottom wall portions 613 and 614 of the members 611 and 612 of the support 610 on both sides of the outer peripheral portion 664 of the rotor portion 662 of the rotating body 660 in the rotation axis direction. Thus, electrical gaps 620 and 621 are formed between the outer peripheral portion 664 of the rotor portion 662 and the electrode plates 600 and 601. Here, the electrical gap 620 is a portion of the internal space 615 of the support 610 sandwiched between one end surface of the outer peripheral portion 664 of the rotor portion 662 and the plate surface of the electrode plate 600 on the fixing member 611 side. The electrical gap 621 is a portion of the internal space 615 of the support 610 that is sandwiched between one end surface of the outer peripheral portion 664 of the rotor portion 662 and the plate surface of the electrode plate 601 on the cover member 612 side. The gap directions of these electrical gaps 620 and 621 substantially coincide with the rotation axis direction of the rotor portion 662, and the width of each electrical gap 620 and 621 in the gap direction is constant.

The internal space 615 of the support 610 including the electrical gaps 620 and 621 is filled with the electrorheological fluid 630 instead of the magnetorheological fluid 150 in a completely filled state, and the electrical gaps 620 and 621 are electrically charged. A viscous fluid 630 is always present. Here, the electrorheological fluid 630 is a kind of “functional fluid”, and is formed by suspending dielectric particles in a liquid base material. As the base material of the electrorheological fluid 630, a material such as oil similar to the case of the magnetic viscous fluid 150 of the first embodiment is used. As the dielectric particles of the electrorheological fluid 630, for example, a powdery dielectric material such as TiO ₂ or barium titanate is used. In the electrorheological fluid 630 having such a component structure, the apparent viscosity increases following the strength of the applied electric field, and the shear stress is proportional to the viscosity and inversely proportional to the size of the space where the electrorheological fluid 630 exists. Reveals increasing characteristics. In the ninth embodiment, the rotating body 660 penetrates through the support 610 in order to suppress leakage of the electrorheological fluid 630 having a relatively low base viscosity when no electric field is applied to the outside of the support 610. An O-ring-shaped seal member 640 is interposed at the contact interface between the bearing 113 and the rotating body 130.

  Each electrode plate 600, 601 is formed by holding a positive electrode 604 and a negative electrode 605 on a base material 603 forming a part of a support 610, as shown in FIG. 21 (the figure shows an example of the electrode plate 600). . Here, the base material 603 is formed of an electrical insulating material such as tetrafluoroethylene resin (PTFE). The positive electrode 604 and the negative electrode 605 are formed of metal or the like in an arc shape along the rotation direction of the rotor portion 132 and are alternately arranged at equal intervals in the rotation diameter direction of the rotor portion 662. In the form, they are connected in a skewer shape at the same potential. Further, the positive electrode 604 and the negative electrode 605 are electrically connected to an energization control circuit 650 that controls the energization voltage to the electrodes 604 and 605. As for the internal / external relationship between the positive electrode 604 and the negative electrode 605 in one electrode plate, as shown in FIG. 21, the positive electrode 604 is disposed on the innermost peripheral side and the negative electrode 605 is disposed on the outermost peripheral side. Although not shown, the negative electrode 605 may be disposed on the innermost peripheral side and the positive electrode 604 may be disposed on the outermost peripheral side.

  When a voltage is applied from the energization control circuit 650, an electric field passing through the electrorheological fluid 630 in the electrical gap 620 is generated between the electrodes 604 and 605 of the electrode plate 600, and the electrorheological fluid is generated in the gap 620. 630 becomes a viscosity state corresponding to the generated electric field. Similarly, an electric field passing through the electrorheological fluid 630 in the electric gap 621 is generated between the electrodes 604 and 605 of the electrode plate 601 by application of a voltage from the energization control circuit 650, and the electrorheological property in the gap 621. The fluid 630 enters a viscosity state corresponding to the generated electric field. As a result, between the elements 610 and 662 facing in the rotational axis direction with the electrical gaps 620 and 621 interposed therebetween, the braking torque in the direction in which the rotor portion 662 is braked against the support 610 by shear stress proportional to the fluid viscosity. Can be generated. As described above, in the present embodiment, it is possible to apply to the rotating body 660 a brake torque that changes following the energized voltages to the electrode plates 600 and 601.

  According to such a ninth embodiment, the energization control circuit 650 controls the energization voltage to the electrode plates 600 and 601 to variably control the viscosity of the electrorheological fluid 630 in contact with the rotor portion 662 to rotate. The brake torque in the body 660 can be uniquely determined. Therefore, the precision of adjusting the engine phase according to the brake torque, and hence the precision of adjusting the valve timing, can be improved by precise control of the energization voltages to the electrode plates 600 and 601.

  Further, according to the ninth embodiment, since the brake torque is generated by the electrorheological fluid 630 having a high viscosity changing speed with respect to the applied electric field, the adjustment response of the valve timing can be improved.

  Further, according to the ninth embodiment, since the shear stress of the electrorheological fluid 630 is inversely proportional to the size of the space where the fluid 630 exists, the shearing stress of the electrorheological fluid 630 in the electrical gaps 620 and 621 having limited widths is large. Brake torque can be generated. In addition, electrode plates 600 and 601 are provided inside the support 610 on both sides of the rotor portion 662 sandwiched in the rotation axis direction, and electrical gaps 620 and 621 are provided between the rotor portion 662 and the electrode plates 600 and 601. Is formed. As a result, brake torque can be applied to the rotor portion 662 from both sides in the rotation axis direction, so that the brake torque can be increased while effectively using the internal space 615 of the support 610. In addition, since the base material 603 of each electrode plate 600, 601 holds the electrodes 604, 605 alternately in the rotational radial direction of the rotor portion 662, an electric field can be generated in a wide range in the rotational radial direction. . Therefore, this also makes it possible to increase and stabilize the brake torque while effectively using the internal space 615 of the support 610. From the above, the physique required to obtain a desired brake torque can be reduced.

  Further, according to the ninth embodiment, since the electrodes 604 and 605 are held only in the latter of the rotating body 660 and the support body 610, it is necessary to provide an insulating material for preventing discharge at the interface between these elements 660 and 610. Absent. In addition, since the electrorheological fluid 630 is completely filled in the internal space 615 of the support 610, the electrical gaps 620 and 621 are always filled with the electrorheological fluid 630. According to this, it becomes difficult to generate discharge between the electrodes 604 and 605.

  In addition, according to the ninth embodiment, the support body 610 in which the rotor portion 662 is accommodated encloses a fluid 630 having higher heat conductivity than air, so that the rotating body is the same as in the first embodiment. Durability can be enhanced by suppressing thermal deformation and thermal degradation of 660 and its support 610. In addition, such a function of suppressing thermal deformation and thermal deterioration is realized by using the electrorheological fluid 630 for generating brake torque without using a special cooling mechanism, which may involve an increase in size and complexity. Absent.

  In addition, in the ninth embodiment, it is not necessary to configure a magnetic circuit through which magnetic flux passes for each member 611, 612 and rotating body 660 of the support 610 as in the first to eighth embodiments. The degree of freedom can be increased and the configuration can be simplified.

  In the ninth embodiment described so far, the electrodes 604 and 605 and the energization control circuit 650 together constitute a “viscosity control means”, and the base material 603 of each electrode plate 600 and 601 is an “electrode holding portion”. It corresponds to.

(Tenth embodiment)
As shown in FIG. 22, the tenth embodiment of the present invention is a modification of the first embodiment. In the tenth embodiment, the rotor portion 701 of the rotating body 700 is formed in an annular plate shape having a constant thickness, and the end of the shaft portion 702 that is connected to the input portion 41 of the phase adjustment mechanism 8 is opposite to the mechanism 8. It is provided concentrically in the part. Thus, the shaft portion 702 protrudes from the rotor portion 701 on the side connected to the phase adjustment mechanism 8, but does not protrude on the opposite side of the mechanism 8.

  The fixing member 711 of the support 710 is formed in a substantially ring plate shape in which the shaft portion 702 penetrates concentrically. The fixed member 711 is provided with a bearing 713 that is exposed in the internal space 712 of the support body 710, and the shaft portion 702 is rotatably supported by the bearing 713 on the phase adjustment mechanism 8 side relative to the rotor portion 701. Has been. Here, the bearing 713 is a radial type rolling bearing, and a lubricating liquid such as grease is pre-enclosed therein.

  The cover member 714 of the support body 710 is formed in a substantially cup shape. As described above, in this embodiment in which the shaft portion 702 does not protrude on the opposite side of the phase adjustment mechanism 8 with respect to the rotor portion 701, no bearing is provided on the bottom wall portion 717 of the cover member 714. Therefore, the support body 710 has a shape in which the shaft portion 702 is cantilevered on the side connected to the mechanism 8 rather than the end face 703 opposite to the phase adjustment mechanism 8.

  The peripheral wall portion 715 of the cover member 714 is liquid-tightly joined to the outer peripheral edge portion of the fixing member 711. As a result, the peripheral wall portion 715 of the cover member 714 has a shape in which the bottom wall portion 717 of the cover member 714 and the inner wall portion 716 of the fixing member 711 are connected. In this embodiment, the inner surface of the bottom wall 717 of the cover member 714 and the inner surface of the inner wall 716 of the fixing member 711 together with the inner surface of the peripheral wall 715 of the cover member 714, the bobbin 720 of the solenoid coil 140, the rotor 701. It is held on the outer peripheral side of the.

  The inner surface of the bottom wall portion 717 of the cover member 714 and the inner surface of the inner wall portion 716 of the fixing member 711 form magnetic gaps 730 and 731 having a constant width with the outer peripheral portion 704 of the rotor portion 701, respectively. Accordingly, the magnetic flux generated by the solenoid coil 140 passes through the fixing member 711, the magnetic gap 731, the outer peripheral portion 704 of the rotor portion 701, the magnetic gap 730, and the cover member 714 in this order as indicated by broken line arrows in FIG.

  As shown in FIG. 22, recesses 718 and 719 are formed on the inner peripheral side portion 705 of the outer peripheral portion 704 of the rotor portion 701 on the inner surface of the bottom wall portion 717 of the cover member 714 and the inner surface of the inner wall portion 716 of the fixing member 711. It is provided in the form which opposes. Each of the recesses 718 and 719 is recessed with a circular cross section concentric with the walls 717 and 716, and expanded gaps 732 and 733 whose width in the gap direction is larger than the magnetic gaps 730 and 731, respectively, between the rotor portion 701. Forming. Thus, the magnetic gaps 730 and 731 communicate with the outer peripheral portions of the respective enlarged gaps 732 and 733, and the bearing 713 is provided on the inner peripheral portion of the enlarged gap 733 closer to the phase adjustment mechanism 8 than the rotor portion 701. It is exposed.

  As shown in FIGS. 22 and 24, a plurality of (three in this embodiment) lightening holes 706 are provided at equal intervals in the rotation direction in a portion 705 forming the enlarged gaps 732 and 733 in the rotor portion 701. Yes. Each lightening hole 706 passes through the rotor portion 701 in the direction of the rotation axis, thereby communicating between the enlarged gaps 732 and 733. Therefore, each of the lightening holes 706 constitutes an internal space 712 of the support 710 together with the enlarged gaps 732 and 733 and the magnetic gaps 730 and 731 communicating with the gaps 732 and 733.

  In such an internal space 712 of the support 710, as shown in FIGS. 22 and 23, the magnetorheological fluid 150 is sealed in a partially filled state. Here, in the stopped state of the rotating body 700 as shown in FIG. 22, the magnetorheological fluid 150 is in addition to the lower part in the vertical direction than the shaft part 702 of the magnetic gaps 730 and 731, and more than the shaft part 702 of the enlarged gaps 732 and 733. It will be in the state which also flowed into the vertical direction lower part and the lightening hole 706 located in the perpendicular direction lower side rather than the axial part 702. FIG. Further, when the solenoid coil 140 generates a magnetic field by energization while the rotating body 700 is rotating, the members 711 and 714 of the support 710 and the members 711 and 714 of the support 710 along the magnetic flux passing through the magnetic gaps 730 and 731 as shown in FIG. The rotor part 701 of the rotating body 700 is magnetized. As a result, the magnetorheological fluid 150 flows through the magnetic gaps 730 and 731 while flowing out of the lightening holes 706 and the enlarged gaps 732 and 733, and generates brake torque to be applied to the rotor unit 701. At this time, since the magnetorheological fluid 150 is difficult to be guided to the inner peripheral portion of the enlarged gap 733 away from the magnetic gap 731, the intrusion of the magnetorheological fluid 150 into the bearing 713 exposed at the inner peripheral portion is suppressed. It is done.

  As described above, in the configuration in which the magnetorheological fluid 150 is partially filled in the internal space 712 of the support 710, the pressure of the internal space 712 is easily increased or decreased by the expansion and contraction of the air due to the change in the environmental temperature. . Such increase / decrease in pressure is desirably suppressed because there is a concern that the support 710 and the rotating body 700 may be deformed to reduce durability. Therefore, as shown in FIGS. 22 and 24, in this embodiment, a vent hole 740 is provided that communicates between the internal space 712 of the support 710 and the inside of the phase adjustment mechanism 8 that is the outside of the support 710. .

  Specifically, the air hole 740 is formed in a form penetrating the shaft portion 702 in the rotation axis direction by an inner peripheral surface of the shaft portion 702 having a cylindrical shape. One end portion 741 of the air hole 740 opens to one end surface 707 of the shaft portion 702 located on the inner peripheral side of the input portion 41 of the phase adjustment mechanism 8. On the other hand, the other end portion 742 of the vent hole 740 is the other end surface 703 of the shaft portion 702 that is positioned vertically above the liquid surface 743 of the magnetorheological fluid 150 in the enlarged gap 732 when the rotating body 700 is stopped. 22).

  With such a configuration, the filter 750 is held via the holder 752 at the end 742 of the vent hole 740 exposed in the internal space 712 of the support 710, and the filter 750 and the holder 752 are connected to the shaft portion. It can be rotated together with 702. Here, the filter 750 is a breathable liquid filter formed thinly from, for example, a composite film of a fluororesin and a urethane resin, and has a characteristic of allowing passage of gas but rejecting passage of liquid. The filter 750 together with the rubber holder 752 covers the end portion 742 of the vent hole 740 in a liquid-tight manner so that the magnetorheological fluid 150 in the inner space 712 flows into the end portion 742 of the vent hole 740. Blocking.

  According to the tenth embodiment described above, the air hole 740 formed by the shaft portion 702 allows the air to flow in and out between the internal space 712 of the support 710 and the inner peripheral side of the input portion 41 due to changes in environmental temperature. It is possible according to the expansion and contraction. That is, when the air in the internal space 712 expands, the air is discharged to the inner peripheral side of the input unit 41 through the vent hole 740. On the other hand, when the air in the internal space 712 contracts, the input unit 41 The outside air on the inner peripheral side of the air is sucked into the internal space 712 through the vent hole 740 without taking in foreign matter into the vent hole 740. According to such a function of the air hole 740, increase / decrease in the pressure of the internal space 712 can be suppressed, so that it is difficult for the durability to decrease due to the deformation of the support 710 and the rotating body 700. In addition, as a result of the pressure increase / decrease in the internal space 712 being suppressed, the bearing 713 exposed in the internal space 712 is less likely to be deteriorated in durability due to the ingress of the magnetorheological fluid 150 or the leakage of the enclosed lubricating liquid.

  Further, the end portion 742 of the air hole 740 that brings about such an effect is exposed to the internal space 712 in which the magnetorheological fluid 150 is sealed, but the liquid surface of the magnetorheological fluid 150 in the stopped state of the rotating body 700. The breathable liquid filter 750 is held above the position 743. Accordingly, it is possible to avoid a situation in which the magnetorheological fluid 150 flows into the vent hole 740 and flows out to the inner peripheral side of the input unit 41. Further, the magnetic viscous fluid 150 attached to the filter 750 by preventing the filter 750 from flowing into the vent hole 740 can be blown away by not only gravity but also the rotational centrifugal force of the shaft portion 702 that rotates together with the filter 750. Therefore, the deterioration of the filter 750 due to the adhesion of the magnetorheological fluid 150 is suppressed. Furthermore, since the filter 750 is provided at the end portion 742 of the air hole 740 exposed to the internal space 712, the filter 750 is protected by the support 710, so that foreign matter outside the support 710 collides with it. It is possible to prevent the filter 750 from being damaged.

  In addition, according to the tenth embodiment, in addition to the magnetic gaps 730 and 731, the enlarged gaps 732 and 733 and the lightening hole 706 are formed as the internal space 712 of the support 710, so that the space 712 is partially filled. The magnetorheological fluid 150 can be increased as much as possible. According to this, the amount of heat energy that can be absorbed by the magnetorheological fluid 150 can be increased, and deterioration of the magnetorheological fluid 150 can be suppressed. Further, according to the lightening hole 706 that passes through the rotor portion 701 in the rotation axis direction and communicates between the enlarged gaps 732 and 733, the fluidity of the magnetorheological fluid 150 between the gaps 732 and 733 is improved. Therefore, local deterioration of the magnetorheological fluid 150 can be suppressed. Furthermore, if the rotor portion 701 is provided with a plurality of lightening holes 706, the rotational inertia of the rotating body 700 is greatly reduced, and therefore the valve timing adjustment responsiveness can be improved. is there.

  In the tenth embodiment described so far, the rotor portion 701 corresponds to a “rotating magnetic portion”, and the inner wall portion 716 of the fixing member 711 and the bottom wall portion 717 of the cover member 714 respectively correspond to “supporting magnetic portions”. The peripheral wall portion 715 of the cover member 714 corresponds to a “coil holding portion”.

(Eleventh embodiment)
As shown in FIG. 25, the eleventh embodiment of the present invention is a modification of the tenth embodiment. In the eleventh embodiment, an oil seal 800 is interposed between the shaft portion 702 of the rotating body 700 and the inner wall portion 716 of the support body 710.

  Specifically, the oil seal 800 is formed of rubber or the like, and has a cylindrical portion 801 and a tapered cylindrical portion 802 on the same axis. The inner peripheral surface of the cylindrical portion 801 is slidably in contact with the outer peripheral surface of the shaft portion 702. The end surface on the large diameter side of the tapered cylindrical portion 802 that is the end surface on the side opposite to the cylindrical portion 801 is in contact with the inner surface of the inner wall portion 716 of the support 710 on the outer peripheral side of the bearing 713. With these configurations, the oil seal 800 provides a liquid-tight seal between the support 710 including the bearing 713 and the shaft portion 702.

  Also in the eleventh embodiment, since the pressure increase / decrease in the internal space 712 of the support 710 is suppressed by the action of the vent hole 740, the oil seal 800 has the cylindrical portion 801 with respect to the shaft portion 702. The contact pressure can be reduced as much as possible. Therefore, when the solenoid coil 140 stops generating the magnetic field, it is possible to suppress a situation in which the brake torque caused by the contact pressure of the oil seal 800 acts on the shaft portion 702 and the valve timing adjustment accuracy deteriorates.

  In the eleventh embodiment described so far, the oil seal 800 corresponds to a “seal member (claim 36)”.

(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 can be applied to various embodiments without departing from the scope of the present invention. it can.

  For example, in the first to ninth embodiments, the rotating bodies 130, 200, 250, 350, and 660 linked to the phase adjustment mechanism 8 are accommodated inside the supports 110, 260, 300, 360, 400, 450, 500, and 610. By reducing the size, the rotational inertia of the rotating bodies 130, 200, 250, 350, and 660 is reduced, but the supporting body can also be accommodated inside the rotating body linked to the phase adjustment mechanism 8. Further, as the phase adjusting mechanism 8 in the first to eleventh embodiments, in addition to the one provided with the differential gear portion 60 in which the planetary carrier 40 is an input rotating body for brake torque as described above, As long as the effect can be obtained, various configurations of mechanisms can be employed.

  In the second embodiment, instead of forming the magnetic pole by the rotor part 202 magnetized in advance, the magnetic pole may be formed by a permanent magnet embedded in the rotor part 202. In any case of forming the magnetic poles, the magnetorheological fluid 150 from the contact interface is formed by forming the magnetic poles on the shaft portion 131, the bearing 113, or the like instead of or in addition to the rotor portion 202. May be prevented from leaking. Further, in the third to eighth, tenth and eleventh embodiments, the magnetic viscous fluid 150 may be prevented from leaking by forming a magnetic pole according to the second embodiment or the above-described modification.

  In the third and fourth embodiments, the cover members 262 and 302 may be formed of a magnetic material, and the cover members 262 and 302 may contribute to the generation of a magnetic field in the magnetic gap 270. Moreover, in 1st, 5th-11th embodiment, you may provide the radiation fin 304 in the cover members 112, 365,405,451,501,612,714 according to 4th embodiment or the said modification. .

  In the sixth and seventh embodiments, a width changing portion 372 according to the fifth embodiment may be formed instead of the constant width portion 412. In the sixth and seventh embodiments, instead of the plurality of fluid reservoirs 416 arranged along the rotation direction of the rotor portion 352, an annular fluid that extends along the rotation direction of the rotor portion 352 according to the sixth embodiment. A reservoir 376 may be formed.

  In the seventh embodiment, instead of forming the magnetic pole by the permanent magnet 454 embedded in the cover member 451, the magnetic pole may be formed by the cover member 451 magnetized in advance. Further, in any case of forming the magnetic pole, the magnetic pole may be formed on the outer peripheral side of the fluid reservoir 416. Further, in the fifth and eighth embodiments, the magnetic viscous fluid 150 is surely trapped in the fluid reservoir 376 by forming magnetic poles in the cover members 365 and 501 according to the seventh embodiment or the above-described modification. Also good.

  In the eighth embodiment, a constant width part 412 according to the sixth embodiment may be formed instead of the width changing part 372. In the eighth embodiment, instead of the annular fluid reservoir 376 extending along the rotational direction of the rotor portion 352, a plurality of fluid reservoirs 416 arranged along the rotational direction of the rotor portion 352 according to the sixth embodiment are provided. It may be formed.

  In the ninth embodiment, a homogeneous electrorheological fluid composed of a single fluid may be used instead of the dispersed electrorheological fluid 630 in which dielectric particles are suspended in a liquid base material. In the ninth embodiment, one of the electrode plates 600 and 601 may be omitted. Furthermore, in the ninth embodiment, the sealing member 640 may not be provided at the contact interface between the support body 610 and the rotating body 660, and deterioration of the characteristics of the electrorheological fluid 630 due to wear powder of the sealing member 640 may be prevented.

  In the tenth and eleventh embodiments, the solenoid coil 140 is embedded in the inner wall 716 of the fixing member 711 of the support 710 according to the third embodiment, and the magnetic gap is provided only on the phase adjustment mechanism 8 side of the rotor 701. 731 may be formed. In the tenth and eleventh embodiments, a configuration according to any of the fifth to eighth embodiments may be adopted. Further, in the tenth and eleventh embodiments, in addition to or instead of providing the vent hole 740 in the shaft portion 702, a vent hole communicating between the inside and the outside of the support body 710 is provided in the support body 710. In that case, it is desirable to provide a breathable liquid filter 750 in the vent hole of the support 710. Furthermore, in the tenth and eleventh embodiments, a plurality of bearings 713 that cantilever-support the shaft portion 702 may be provided on the fixing member 711 to improve the supportability of the shaft portion 702. In addition, in the tenth and eleventh embodiments, the shaft portion 702 that protrudes to the opposite side of the phase adjustment mechanism 8 with respect to the rotor portion 701 is supported by a bearing provided on the cover member 714 to support the shaft portion 702. In such a case, the air-permeable liquid filter 750 may be provided in such a manner that the air holes 740 are opened at a plurality of locations on the outer peripheral surface of the shaft portion 702 and the openings are covered. Good.

  In addition to the device for adjusting the valve timing of the intake valve as in the first to eleventh embodiments, the present invention provides a device for adjusting the valve timing of the exhaust valve, and valve timings of both the intake valve and the exhaust valve. It can be applied to a device for adjusting.

It is sectional drawing which shows the valve timing adjustment apparatus of 1st embodiment. 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 sectional drawing which shows the fluid brake of 1st embodiment. It is a characteristic view showing the correlation between the magnetic field applied to the magnetorheological fluid and the viscosity of the magnetorheological fluid. It is a schematic diagram which shows the correlation of the energization current to a solenoid coil, and a brake torque. It is sectional drawing which expands and shows the principal part of the fluid brake of 2nd embodiment. It is sectional drawing which shows the fluid brake of 3rd embodiment. It is sectional drawing which shows the fluid brake of 4th embodiment. FIG. 10 is a view on arrow X in FIG. 9. It is sectional drawing which shows the fluid brake of 5th embodiment. It is the XII-XII sectional view taken on the line of FIG. It is sectional drawing for demonstrating the characteristic of 5th embodiment. It is a characteristic view which shows the correlation with environmental temperature and the base viscosity of a magnetorheological fluid. It is sectional drawing which shows the fluid brake of 6th embodiment. It is the XVI-XVI sectional view taken on the line of FIG. It is sectional drawing which shows the fluid brake of 7th embodiment. It is the XVIII-XVIII sectional view taken on the line of FIG. It is sectional drawing which shows the fluid brake of 8th embodiment. It is sectional drawing which shows the fluid brake of 9th embodiment. It is a front view which shows the electrode plate of FIG. It is sectional drawing which shows the fluid brake of 10th embodiment. It is sectional drawing for demonstrating the characteristic of 10th embodiment. It is a front view which shows the rotary body of FIG. It is sectional drawing which shows the fluid brake of 11th embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Valve timing adjustment device, 2 cam shaft, 4 brake system, 8 phase adjustment mechanism, 60 differential gear part, 100 fluid brake, 110,260,300,360,400,450,500,610,710 support body, 111 , 261, 361, 401, 503, 611, 711 Fixing member, 112, 262, 302, 365, 405, 451, 501, 612, 714 Cover member, 113, 114 Bearing, 115, 118, 505, 717 Bottom wall (Support magnetic part), 116, 504, 715 peripheral wall part (coil holding part), 117 peripheral wall part, 119, 268, 369, 409, 508, 615, 712 internal space, 120, 121, 270, 370, 410, 510 , 730, 731 Magnetic gap, 130, 200, 250, 350, 660, 700 Rotating body, 131, 702 Shaft, 132, 202, 252, 352, 701 Rotor (rotating magnetic part), 134, 704 Outer part, 140 Solenoid coil (viscosity control means), 150 Magnetorheological fluid, 160, 650 Control circuit (viscosity control means), 204 inner peripheral part, 206 magnetized part, 264, 368, 408 peripheral wall part, 266, 362, 403 inner wall part (coil holding part), 269, 366, 406, 452, 613, 614 Bottom wall portion, 304 Radiation fin (heat radiation portion), 306 Bottom wall portion (heat radiation portion), 354 Outer peripheral portion (rotating taper portion), 364, 404 Outer peripheral portion (support taper portion), 367, 407 Groove portion, 372 Width changing portion 374, 412 Constant width part, 376, 416 Fluid reservoir, 454 Permanent magnet, 502, 716 Inner wall part (supporting magnetic part), 600, 6 01 Electrode plate, 603 Base material (electrode holding part), 604 Positive electrode (electrode / viscosity control means), 605 Negative electrode (electrode / viscosity control means), 620, 621 Electrical gap, 630 Electroviscous fluid, 640 Seal member , 662 Rotor part, 664 Outer part, 703 End face, 705 part, 706 Thickening hole, 713 Bearing (rolling bearing), 718, 719 Recessed part, 720 Bobbin, 732, 733 Expansion gap, 740 Vent hole, 742 End part, 743 Liquid level, 750 filter, 752 holder, 800 oil seal (seal member), 801 cylindrical part, 802 tapered cylinder part

Claims (45)

A valve timing adjustment device for an internal combustion engine that adjusts the valve timing of at least one of an intake valve and an exhaust valve whose camshaft opens and closes by torque transmission from a crankshaft,
A rotating body to which a brake torque according to the viscosity of the functional fluid is applied by contacting the functional fluid having a variable viscosity;
Viscosity control means for variably controlling the viscosity of the functional fluid;
A valve timing adjusting device comprising: a phase adjusting mechanism that adjusts a relative phase between the crankshaft and the camshaft in accordance with the brake torque input from the rotating body. The functional fluid is a magnetorheological fluid;
2. The valve timing adjusting device according to claim 1, wherein the viscosity control means variably controls the viscosity of the magnetorheological fluid by a magnetic field applied to the magnetorheological fluid.   The valve timing adjusting device according to claim 2, wherein the magnetorheological fluid is obtained by suspending magnetic particles in oil.   4. The valve according to claim 2, wherein the viscosity control means includes a solenoid coil that generates a magnetic field to be applied to the magnetorheological fluid, and an energization control circuit that controls an energization current to the solenoid coil. Timing adjustment device. A support body that rotatably supports the rotating body and that forms a magnetic gap between which the solenoid coil generates a magnetic field;
5. The valve timing adjusting device according to claim 4, wherein the solenoid coil generates a magnetic field in a state where the magnetorheological fluid is interposed in the magnetic gap.   6. The valve timing adjusting device according to claim 5, wherein one of the rotating body and the support is accommodated in the other and the magnetorheological fluid is sealed therein.   The valve timing adjusting device according to claim 6, wherein at least one of the rotating body and the support body forms a magnetic pole along an interface between the rotating body and the support body.   The valve timing adjusting device according to claim 6 or 7, wherein the rotating body is accommodated in the support body. The rotating body is formed of a magnetic material, and has a rotating magnetic part that is accommodated inside the support body.
The support is made of a magnetic material, provided on both sides of the rotating magnetic portion in the direction of the rotation axis, and formed of a supporting magnetic portion that forms the magnetic gap between the rotating body and the magnetic material. 9. The valve timing adjusting device according to claim 8, further comprising a coil holding portion that connects the support magnetic portions and holds the solenoid coil on an outer peripheral side of the rotating magnetic portion. The rotating body is formed of a magnetic material, and has a rotating magnetic part that is accommodated inside the support body.
The said support body is formed with a magnetic material, and has a coil holding | maintenance part which hold | maintains the said solenoid coil in the location which faces the said rotation magnetic part and a rotating shaft direction on both sides of the said magnetic gap. Valve timing adjustment device.   The said support body is provided in the opposite side to the said coil holding | maintenance part on both sides of the said rotation magnetic part in the rotating shaft direction, and has a thermal radiation part which radiates | emits an internal heat | fever outside. Valve timing adjustment device. The support communicates with the magnetic gap and forms a fluid reservoir for trapping the magnetorheological fluid;
When the solenoid coil stops generating a magnetic field, the magnetorheological fluid is discharged from the magnetic gap to the fluid reservoir, and when the solenoid coil generates a magnetic field, the magnetorheological fluid is discharged from the fluid reservoir to the magnetic gap. The valve timing adjusting device according to any one of claims 8 to 11, wherein the valve timing adjusting device is sucked into the valve.   The valve timing adjusting device according to claim 12, wherein the fluid reservoir is formed between the support and the rotating body.   The valve timing adjusting device according to claim 13, wherein the magnetorheological fluid is partially filled in the support.   The valve timing adjusting device according to any one of claims 12 to 14, wherein the support forms the fluid reservoir on a lower side in a vertical direction with respect to the magnetic gap.   The valve timing adjusting device according to any one of claims 12 to 15, wherein the support body forms the fluid reservoir outside the rotational gap of the rotating body with respect to the magnetic gap.   The valve timing adjusting device according to claim 16, wherein the support forms the fluid reservoir in an annular shape extending along a rotation direction of the rotating body.   The valve timing adjusting device according to claim 16, wherein the support body forms a plurality of fluid reservoirs along a rotation direction of the rotating body.   The valve timing adjusting device according to any one of claims 12 to 18, wherein the support forms a magnetic pole around the fluid reservoir.   The magnetic field intensity generated by a magnetic pole around the fluid reservoir at a communication location between the magnetic gap and the fluid reservoir is weaker than the magnetic field strength generated by the solenoid coil at the communication location. 20. The valve timing adjusting device according to 19. Magnetic flux generated by the solenoid coil passes through the magnetic gap in the gap direction,
The valve timing adjusting device according to any one of claims 12 to 20, wherein the magnetic gap has a width changing portion that widens in the gap direction as it is closer to the fluid reservoir.   The rotary body has a rotating taper portion that is spaced apart from the support body toward the outer side in the radial direction of rotation at a location facing the support body in the rotation axis direction across the width changing portion. The valve timing adjusting device according to claim 21.   The said support body has a support taper part which is spaced apart from the said rotary body in the part which faces the said rotary body in the rotation axis direction on both sides of the said width change part, so that it goes to the outer side of a rotation radial direction. The valve timing adjusting device according to 21 or 22. The functional fluid is an electrorheological fluid;
The valve timing adjusting device according to claim 1, wherein the viscosity control unit variably controls the viscosity of the electrorheological fluid by an electric field applied to the electrorheological fluid.   25. The valve timing adjusting apparatus according to claim 24, wherein the viscosity control means includes a plurality of electrodes that generate an electric field between each other and an energization control circuit that controls an energization voltage to each of the electrodes. A support body that rotatably supports the rotating body and that forms an electrical gap between the rotating body and the electrode that generates an electric field;
26. The valve timing adjusting apparatus according to claim 25, wherein the electrode generates an electric field in a state where the electrorheological fluid is interposed in the electrical gap.   27. The valve timing adjusting device according to claim 26, wherein the electrorheological fluid is enclosed in one of the rotating body and the support body while the other is accommodated.   28. The valve timing adjusting device according to claim 27, further comprising a seal member that seals an interface between the rotating body and the support.   The valve timing adjusting device according to claim 27 or 28, wherein the rotating body is accommodated in the support body.   The support has electrode holding portions that alternately hold positive and negative electrodes as the electrodes in the rotational radial direction of the rotating body at locations facing the rotating body in the rotation axis direction across the electrical gap. 30. The valve timing adjusting device according to any one of claims 26 to 29, comprising:   31. The valve timing adjusting device according to claim 30, wherein one of the rotating body and the support is accommodated in the other and the electrorheological fluid is completely filled therein. The rotating body is housed inside the support;
32. The valve timing according to claim 30 or 31, wherein the electrode holding portions are provided on both sides sandwiching the rotating body in a rotation axis direction, and form the electrical gap between the rotating bodies. Adjustment device. The magnetorheological fluid is partially filled inside the support;
The rotating body has a shaft portion that penetrates the support body and is linked to the phase adjustment mechanism,
The valve timing according to any one of claims 8 to 23, wherein at least one of the support body and the shaft portion forms a vent hole communicating between the inside and the outside of the support body. Adjustment device.   The valve timing adjusting device according to claim 33, wherein the support includes a rolling bearing that is exposed to the inside of the support and supports the shaft portion.   The valve timing adjusting apparatus according to claim 34, wherein a lubricating liquid is sealed in the rolling bearing. The valve timing adjusting device according to any one of claims 33 to 35, further comprising a seal member that seals between the support and the shaft portion.
  37. The end of the vent hole exposed to the inside of the support body is positioned above the liquid surface of the magnetorheological fluid in the vertical direction when the rotating body is stopped. The valve timing adjusting device according to any one of claims.   38. The filter according to any one of claims 33 to 37, wherein a filter that allows passage of gas and rejects passage of liquid is provided at an end of the vent hole exposed inside the support. Valve timing adjustment device.   The said vent hole is formed in the said shaft part, and connects between the inside of the said support body, and the inside of the said phase adjustment mechanism used as the exterior of the said support body, The any one of Claims 33-38 characterized by the above-mentioned. The valve timing adjusting device according to one item.   The shaft portion has a cylindrical shape in which the vent hole penetrates in a rotation axis direction, and an end portion of the vent hole is opened at an end surface of the shaft portion exposed to the inside of the support body. Item 40. The valve timing adjustment device according to Item 39.   41. The valve timing adjusting device according to claim 40, wherein a filter that allows passage of gas and rejects passage of liquid is provided at an end of the vent hole that opens to the end face.   42. The valve timing adjusting device according to claim 40 or 41, wherein the shaft portion is cantilevered by the support body on a side closer to the phase adjusting mechanism than the end face. The magnetorheological fluid is partially filled inside the support;
9. The rotating body is formed with an enlarged gap between the support body and an enlarged gap in which the width of the magnetic gap in the gap direction is larger than that of the magnetic gap and into which the magnetorheological fluid flows. The valve timing adjusting device according to any one of? 23, 33-42.   44. The valve timing adjusting device according to claim 43, wherein the support body has a rolling bearing that is exposed to the enlarged gap and supports the shaft portion.   45. The valve timing adjusting device according to claim 43, wherein the rotating body has a lightening hole in a portion where the enlarged gap is formed.

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