JP6338906B2 - Torque converter with lock-up clutch - Google Patents

Description

  The present invention relates to a torque converter with a lockup clutch in which a magnetorheological fluid (= MR fluid) is used as a working fluid and the lockup clutch is an MR fluid clutch.

  Conventionally, there is known a torque converter with a lockup clutch in which MR fluid is used as a working fluid instead of oil and the lockup clutch is an MR fluid clutch (see, for example, Patent Document 1).

JP2013-92204A

  However, in the conventional torque converter with a lock-up clutch, the electromagnetic coil is disposed at the radially outer position of the magnetorheological fluid layer that generates a transmission torque in accordance with the viscosity change due to the magnetic field (coil outer peripheral arrangement). . For this reason, there existed a problem that transmission torque became small, power consumption increased, and particle separation of magnetorheological fluid occurred.

  The present invention has been made paying attention to the above problems, and is a torque converter with a lock-up clutch that can achieve both an improvement in transmission torque, a reduction in power consumption, and a suppression of particle separation in a magnetorheological fluid. The purpose is to provide.

In order to achieve the above object, the present invention provides a pump impeller coupled to an input shaft via a converter cover, a turbine runner disposed opposite to the pump impeller and coupled to an output shaft, and a magnet enclosed inside. A viscous fluid. The lock-up clutch is constituted by an MR fluid clutch using a magnetorheological fluid.
A torque converter with a lock-up clutch, comprising: a first disk coupled to the pump impeller; a second disk coupled to the turbine runner; and a disk facing surface of the first disk and the second disk. And an electromagnetic coil that generates a magnetic field by energizing the formed magnetorheological fluid layer.
The electromagnetic coil is disposed at a radially inner position of the magneto-rheological fluid layer that generates a transmission torque according to a viscosity change caused by a magnetic field.
Each of the first disk and the second disk has a multi-layer disk structure having a donut disk shape.
The magnetorheological fluid layer was formed in a plurality of layers so as to extend along a plane orthogonal to the converter rotation axis.

Therefore, the electromagnetic coil is arranged (coil inner circumference arrangement) at the radially inner position of the magnetorheological fluid layer that generates a transmission torque in accordance with the viscosity change caused by the magnetic field.
That is, due to the arrangement of the inner circumference of the coil, the outer diameter of the magnetorheological fluid layer disposed at the radially outer position of the electromagnetic coil does not change even if the cross-sectional area of the electromagnetic coil is increased. For this reason, when the outer diameter dimension of the torque converter is defined, the torque transmission area by the magnetorheological fluid layer is expanded and the transmission torque is improved.
When the desired coil cross-sectional area (magnetomotive force = current × number of turns) is maintained due to the arrangement of the inner circumference of the coil, the overall length of the coil winding is shortened. For this reason, the electrical resistance of an electromagnetic coil reduces and power consumption is suppressed.
Due to the inner circumference arrangement of the coil, a force against the centrifugal force acts on the ferromagnetic particles of the magnetorheological fluid. For this reason, particle separation of the magnetorheological fluid is suppressed.
As a result, it is possible to achieve an improvement in transmission torque, suppression of power consumption, and suppression of particle separation of the magnetorheological fluid. In addition, it is possible to increase the transmission torque capacity of the MR fluid clutch while achieving improved manufacturability and cost reduction when multilayering the magnetorheological fluid layer.

It is sectional drawing which shows the torque converter with a lockup clutch of Example 1. FIG. It is operation | movement explanatory drawing which shows the torque converter with a lockup clutch of the comparative example by coil outer periphery arrangement | positioning. It is operation | movement explanatory drawing which shows the torque converter with a lockup clutch of Example 1 by coil inner peripheral arrangement | positioning. It is sectional drawing which shows the torque converter with a lockup clutch of Example 2. FIG. FIG. 6 is a current-torque characteristic diagram showing the relationship of torque to current from a clutch control circuit of a torque converter with a lockup clutch according to a second embodiment.

  Hereinafter, the best mode for realizing a torque converter with a lock-up clutch according to the present invention will be described based on Example 1 and Example 2 shown in the drawings.

First, the configuration will be described.
The configuration of the torque converter with a lock-up clutch in the first embodiment will be described by dividing it into [overall configuration] and [MR fluid clutch configuration].

[overall structure]
FIG. 1 shows a torque converter A1 with a lock-up clutch according to a first embodiment applied to an electric vehicle (hybrid vehicle, electric vehicle, etc.). The overall configuration will be described below with reference to FIG.

  As shown in FIG. 1, the torque converter A1 with a lock-up clutch includes a pump impeller 1, a turbine runner 2, a stator 3, a magnetorheological fluid 4 (hereinafter referred to as “MR fluid 4”), and an MR fluid. And a clutch 5.

  The pump impeller 1 is connected to an input shaft 6 via a converter cover 7. The pump impeller 1 is manufactured from an aluminum alloy or the like, and includes a pump outer shell 1a, a plurality of pump blades 1b protruding from the inner surface of the pump outer shell 1a toward the turbine runner 2, and a plurality of pump blades 1b. A pump inner shell 1c connecting the inner ends.

  A rotary shaft 9 is connected to the pump impeller 1 at a position including the output shaft 8, and a slip ring 10 for applying a current to the electromagnetic coil 54 of the MR fluid clutch 5 is provided on the outer peripheral surface of the rotary shaft 9. 10 is provided. The ring contacts 12 and 12 of the coil current application terminal 11 are brought into contact with the slip rings 10 and 10 by spring bias. Here, the slip rings 10, 10 and the electromagnetic coil 54 are connected by a lead wire (not shown) via the pump outer shell 1 a and the converter cover 7. A rotation sensor gear 13 for detecting the rotational speed of the input shaft is fixed to the end surface position of the pump impeller 1 on the drive source side by a bolt (not shown).

  The turbine runner 2 is disposed opposite to the pump impeller 1 and is connected to the output shaft 8 via the output hub 14. The turbine runner 2 is manufactured from an aluminum alloy or the like, and includes a turbine outer shell 2a, a plurality of turbine blades 2b protruding from the inner surface of the turbine outer shell 2a toward the pump impeller 1, and the turbine blade 2b. A turbine inner shell 2c connecting the inner end portions.

  The stator 3 is disposed between the pump impeller 1 and the turbine runner 2 and is disposed in an inner region of the opposed regions of the two and 1, and is provided via a one-way clutch 16 to a case 15 that is a stationary fixing member. It is done. The stator 3 includes a stator inner ring 3a, a plurality of stator blades 3b protruding from the outer surface of the stator inner ring 3a in the outer diameter direction, and a stator outer ring 3c that connects the outer ends of the stator blades 3b. Configured.

  The MR fluid 4 is covered with the pump impeller 1 and the converter cover 7 and is enclosed in a converter space sealed by a first MR fluid seal 17, a second MR fluid seal 18, and a third MR fluid seal 19. Here, the MR fluid 4 is a functional fluid in which ferromagnetic particles such as iron nanoparticles are dispersed in oil, and the viscosity changes according to an external magnetic field. The MR fluid 4 forms a circulating flow in the torus portion where the pump impeller 1, the turbine runner 2, and the stator 3 gather when the torque converter is operated, and is filled in the magnetorheological fluid layer 53 of the MR fluid clutch 5.

  The MR fluid clutch 5 is a lock-up clutch using the MR fluid 4, and is interposed between the converter cover 7 and the turbine runner 2, and performs lock-up fastening, slip lock-up fastening, and lock-up release. At the time of lock-up fastening, the input shaft 6 and the output shaft 8 are directly connected. At the time of slip lockup fastening, the input shaft 6 and the output shaft 8 are fastened while allowing a predetermined differential rotation. When the lockup is released, the input shaft 6 and the output shaft 8 are connected via a torque converter using the MR fluid 4.

[MR fluid clutch configuration]
Hereinafter, the MR fluid clutch configuration will be described with reference to FIG.
As shown in FIG. 1, the MR fluid clutch 5 includes a first disk 51, a second disk 52, a magnetorheological fluid layer 53 (hereinafter referred to as "MR fluid layer 53"), an electromagnetic coil 54, A yoke portion 55 and a clutch control circuit 56 are provided.

  The first disk 51 has a multi-layered disk structure having a donut shape, and is connected to the pump impeller 1 via the converter cover 7. The first disk 51 has an inner peripheral end portion embedded in an outer peripheral surface of a first flange portion 57 extending in the axial direction from the converter cover 7 toward the turbine runner 2. As the first disk 51, three spaces of equal intervals are formed by a total of four disks, two of which are embedded in the outer peripheral surface of the first flange portion 57 and two of which are also used as the yoke portions 55 provided on both sides thereof. It has a multi-layer disc structure. Note that the thickness of the two discs on both sides that also serve as the yoke portion 55 is thicker than the thickness of the two discs arranged inside. The first disk 51 and the yoke portion 55 are made of a ferromagnetic material such as iron, and the first flange portion 57 is made of an aluminum alloy or the like.

  The second disk 52 has a multi-layer disk structure with a donut shape, and is connected to the turbine runner 2. The second disk 52 has an outer peripheral end portion embedded in an inner peripheral surface of a second flange portion 58 extending in the axial direction from the outer peripheral end portion of the turbine runner 2 toward the converter cover 7. The second disk 52 has a three-layered disk structure embedded in the inner peripheral surface of the second flange portion 58 and is arranged at an intermediate position between three equally spaced spaces formed by the first disk 51. The thickness of the three disks is set to the same thickness as the thickness of the two first disks 51 embedded in the outer peripheral surface of the first flange portion 57. The second disk 52 is made of a ferromagnetic material such as iron, and the second flange portion 58 is made of an aluminum alloy or the like.

  The MR fluid layer 53 is formed in a plurality of layers so as to extend along the plane perpendicular to the converter rotation axis CL between the disk-facing surfaces of the first disk 51 and the second disk 52. In the first embodiment, as shown in FIG. 1, six MR fluid layers 53 filled with the MR fluid 4 are formed at equal intervals. The radial direction range in which the MR fluid layer 53 is set is from the position of the core region where the MR fluid 4 stays when the circulating flow is formed in the torus portion in order to suppress an increase in the radial size. The range up to the position of the outer diameter end region is set.

  The electromagnetic coil 54 generates a magnetic field by energizing the MR fluid layer 53, and is disposed at a radially inner position of the six MR fluid layers 53 that generate a transmission torque in accordance with a viscosity change caused by the magnetic field. The electromagnetic coil 54 is disposed at an inner peripheral side position of the first flange portion 57, and an outer peripheral portion excluding the first flange portion 57 is disposed in a cross-sectional right triangle region surrounded by the V-shaped yoke portion 55. . Here, the reason why the electromagnetic coil 54 has a right-angled triangular cross section is that the torque converter T / C with a lock-up clutch using the hydraulic clutch indicated by the phantom line in FIG. This is because the design concept of applying the torque converter A1 with a lock-up clutch using the fluid clutch 5 is applied.

  The yoke portion 55 constitutes a magnetic circuit based on the lines of magnetic force when the electromagnetic coil 54 is energized, and is set in a region of the converter cover 7 where the magnetorheological fluid layer 53 is formed. That is, a part of the converter cover 7 connected to the pump impeller 1 is provided integrally with the converter cover 7 while also serving as the first disk 51.

  The clutch control circuit 56 is a circuit that controls the current applied to the electromagnetic coil 54 in accordance with input information. For example, when the MR fluid clutch 5 is unlocked, the current applied to the electromagnetic coil 54 is zero, and when the MR fluid clutch 5 is locked, transmission torque that does not allow slippage with respect to the input torque (> input torque). Is applied to the electromagnetic coil 54. Further, when the slip lockup of the MR fluid clutch 5 is engaged, a current value determined so as to obtain the target slip amount is applied to the electromagnetic coil 54.

Next, the operation will be described.
The operation of the torque converter A1 with the lockup clutch according to the first embodiment will be described by dividing it into [comparison operation by coil inner arrangement] and [other characteristic operation].

[Comparison effect by coil inner arrangement]
First, a torque converter with a lock-up clutch based on a coil outer peripheral arrangement in which an electromagnetic coil is arranged at the outer peripheral position of the MR fluid clutch is taken as a comparative example (FIG. 2). In the case of this comparative example, since it is coil outer periphery arrangement | positioning, it has the subject enumerated below.

(a ′) Due to the outer circumference arrangement of the coil in which the transmission torque is reduced, as shown in FIG. 2, the outer diameter L1 ′ of the MR fluid clutch 5 ′ arranged at the radially inner position of the electromagnetic coil 54 ′ becomes the electromagnetic coil 54 ′. The larger the cross-sectional area, the shorter. For this reason, when the outer diameter dimension of the torque converter is defined as L, the torque transmission area by the MR fluid clutch 5 ′ is reduced.

(b ′) Due to the arrangement of the outer periphery of the coil that increases power consumption, as shown in FIG. 2, when the desired coil cross-sectional area (magnetomotive force = current × number of turns) is maintained, the total length of the coil winding becomes long. For this reason, the electrical resistance of the electromagnetic coil 54 'increases and the power consumption increases.

(c ′) Due to the arrangement of the outer circumference of the coil in which particle separation of the MR fluid occurs, the same force in the outer diameter direction as the centrifugal force acts on the ferromagnetic particles of the MR fluid. For this reason, the ferromagnetic particles of the MR fluid are separated.

  In contrast, the first embodiment employs a configuration in which the electromagnetic coil 54 is disposed at the radially inner position of the MR fluid layer 53 that generates a transmission torque in accordance with a change in viscosity due to a magnetic field (coil inner circumferential arrangement) (see FIG. 3). For this reason, as described below, it is possible to achieve an improvement in transmission torque, suppression of power consumption, and suppression of particle separation of the MR fluid 4 in combination.

(a) Improvement of transmission torque Due to the arrangement of the inner circumference of the coil, the outer diameter L1 of the MR fluid layer 53 arranged at the radially outer position of the electromagnetic coil 54 increases the cross-sectional area of the electromagnetic coil 54 as shown in FIG. However, it can be secured longer than the outer diameter L1 ′ of the comparative example without changing. For this reason, when the outer diameter dimension of the torque converter is defined as L, the torque transmission area by the MR fluid layer 53 is expanded, and the transmission torque is improved.
Further, since the MR fluid layer 53 is arranged on the radially outer side, even if the MR fluid layer 53 has the same radial width, the torque transmission area can be increased, and the MR fluid layer 53 is also away from the converter rotation axis CL. Therefore, even if the shear force of the MR fluid 4 is the same, the transmitted torque can be increased.

(b) Suppression of power consumption As shown in FIG. 3, when the desired coil cross-sectional area (magnetomotive force = current × number of turns) is maintained, the total length of the coil winding is shortened as shown in FIG. For this reason, the electrical resistance of the electromagnetic coil 54 decreases, and power consumption is suppressed.
The magnetic field generated by the electromagnetic coil 54 is determined by the coil current and its cross section, but when the cross section is the same, the circumferential length of the electromagnetic coil 54 is shortened by arranging it radially inward. The volume can be reduced. Further, the material of the electromagnetic coil 54 is often a metal having a heavy specific gravity such as copper, but even in such a case, by disposing it in the radial direction, the inertia can be reduced and the controllability can be improved. .

(c) Due to the arrangement of the inner periphery of the particle separation suppressing coil of the MR fluid 4, a force (force in the inner diameter direction) against the centrifugal force acts on the ferromagnetic particles of the MR fluid 4. For this reason, particle separation of the MR fluid 4 is suppressed.
That is, as in the comparative example, when particle separation of the MR fluid occurs, the radial transmission torque distribution in the torque transmission area by the MR fluid layer becomes a non-uniform distribution such that the lower the torque is on the inner diameter side, the total transmission Torque decreases or varies.
On the other hand, when the particle separation of the MR fluid 4 is suppressed, the radial transmission torque distribution in the torque transmission area by the MR fluid layer 53 becomes a uniform distribution in which the torque change from the inner diameter side to the outer diameter side is suppressed. The total transmission torque is stably secured.

[Other features]
In the first embodiment, each of the first disk 51 and the second disk 52 has a multi-layer disk structure having a donut disk shape, and the MR fluid layer 53 has a plurality of layers extending along a plane orthogonal to the converter rotation axis CL. The structure to be formed was adopted.
For example, in the case of an MR fluid clutch having a cylindrical MR fluid layer, if a plurality of MR fluid layers are to be formed, gap management is required to equalize the plurality of uniform gaps, making it difficult to make multilayers in manufacturing. .
On the other hand, since the MR fluid layer 53 serving as a torque transmission surface is extended in the radial direction, when the MR fluid layer 53 is multilayered, the axial gap between the first disk 51 and the second disk 52 having a multilayer disk structure is used. It is possible to improve manufacturability simply by managing the above. The torque transmission surface is increased by increasing the number of MR fluid layers 53, and the demand for increasing the transmission torque capacity of the MR fluid clutch 5 can be met.
As described above, when the MR fluid layer 53 is multi-layered, the transmission torque capacity of the MR fluid clutch 5 can be increased while improving the manufacturability and reducing the cost.

In the first embodiment, the inner peripheral end portion of the first disk 51 is provided on the outer peripheral surface of the first flange portion 57 extending in the axial direction from the converter cover 7 toward the turbine runner 2. The configuration in which the outer peripheral end of the second disk 52 is provided on the inner peripheral surface of the second flange portion 58 extending in the axial direction from the outer peripheral end of the pump impeller 2 toward the converter cover 7 is employed.
For example, if the second disk is connected to the outer peripheral end of the pump impeller as it is, the second disk will extend radially outward, and further, the first disk connecting portion will be provided outside the second disk. As a result, the overall size of the apparatus increases and the vehicle mountability deteriorates.
On the other hand, the attachment range of the first disc 51 and the second disc 52 is defined as the range of the first flange portion 57 and the second flange portion 58 radially inward from the outer peripheral end portion of the pump impeller 2. That is, the outer peripheral end of the second disk 52 is prevented from projecting radially outward from the outer peripheral end of the pump impeller 2.
Therefore, an increase in the radial size of the entire device of the torque converter A1 with the lock-up clutch is avoided, and good vehicle mountability can be ensured.

In the first embodiment, the region of the converter cover 7 where the MR fluid layer is formed is a yoke portion 55 that constitutes a magnetic circuit using magnetic field lines. And the structure which has arrange | positioned the electromagnetic coil 54 in the position which is the inner peripheral side position of the 1st flange part 57, Comprising: The outer peripheral part except the 1st flange part 57 is surrounded.
For example, when the electromagnetic coil surrounded by the yoke portion is formed separately and provided on the inner surface of the converter cover, the converter cover protrudes in the axial direction.
On the other hand, by providing the yoke portion 55 serving as a cover integrally with a part of the converter cover 7, the converter cover 7 is prevented from protruding in the axial direction while the electromagnetic coil 54 is surrounded by the yoke portion 55. Is done.
Therefore, an increase in the axial size of the torque converter A1 with the lockup clutch as a whole can be avoided, and good vehicle mountability can be ensured.

In the first embodiment, slip rings 10 and 10 for applying a current to the electromagnetic coil 54 are provided in the rotary shaft portion 9 of the pump impeller 1 including the output shaft 8, and the electromagnetic coil 54 is connected to the pump impeller 1. The structure provided in the cover 7 was adopted.
For example, when an electromagnetic coil is provided on the turbine liner side, the turbine liner is contained in a torque converter cover that rotates with the pump impeller, so two sets of slip rings are provided so that current can be passed even when there is relative rotation. There must be.
On the other hand, since the slip rings 10 and 10 are provided in the rotating shaft part 9 of the pump impeller 1 and the electromagnetic coil 54 is provided on the same pump impeller 1 side, the pair of slip rings 10 and 10 and the electromagnetic coil 54 are provided. Direct electrical connection is possible.
Therefore, the slip rings 10 and 10 and the electromagnetic coil 54 can be electrically connected with a simple configuration in which only one set of slip rings 10 and 10 is provided.

Next, the effect will be described.
In the torque converter A1 with the lock-up clutch according to the first embodiment, the following effects can be obtained.

(1) A pump impeller 1 connected to the input shaft 6 via a converter cover 7, a turbine runner 2 disposed opposite to the pump impeller 1 and connected to the output shaft 8, and a magnetorheological fluid sealed inside (MR fluid 4) and a torque converter with a lockup clutch in which the lockup clutch is constituted by an MR fluid clutch 5 using a magnetorheological fluid (MR fluid 4),
A first disk 51 connected to the pump impeller 1;
A second disk 52 connected to the turbine runner 2;
An electromagnetic coil 54 that generates a magnetic field by energizing a magneto-rheological fluid layer (MR fluid layer 53) formed between the disk-facing surfaces of the first disk 51 and the second disk 52;
The electromagnetic coil 54 is disposed at a radially inner position of the magnetorheological fluid layer (MR fluid layer 53) that generates a transmission torque according to a change in viscosity due to a magnetic field.
For this reason, improvement of transmission torque, suppression of power consumption, and particle separation suppression of the magnetorheological fluid (MR fluid 4) can be achieved together.

(2) Each of the first disk 51 and the second disk 52 has a multi-layer disk structure having a donut shape,
The magnetorheological fluid layer (MR fluid layer 53) was formed in a plurality of layers so as to extend along a plane orthogonal to the converter rotation axis CL.
For this reason, in addition to the effect of (1), when the magnetorheological fluid layer (MR fluid layer 53) is multi-layered, the transmission torque capacity of the MR fluid clutch 5 is increased while improving the manufacturability and reducing the cost. Can be planned.

(3) An inner peripheral end portion of the first disk 51 is provided on an outer peripheral surface of a first flange portion 57 extending in the axial direction from the converter cover 7 toward the turbine runner 2,
The outer peripheral end portion of the second disk 52 is provided on the inner peripheral surface of the second flange portion 58 that extends in the axial direction from the outer peripheral end portion of the pump impeller 1 toward the converter cover 7.
For this reason, in addition to the effect (2), an increase in the radial size of the entire device of the torque converter A1 with the lock-up clutch can be avoided, and good vehicle mountability can be ensured.

(4) A region of the converter cover 7 in which the magnetoviscous fluid layer (MR fluid layer 53) is formed is a yoke portion 55 that constitutes a magnetic circuit using a line of magnetic force,
The electromagnetic coil 54 is disposed at a position on the inner peripheral side of the first flange portion 57 and an outer peripheral portion excluding the first flange portion 57 is surrounded by the yoke portion 55.
For this reason, in addition to the effects (1) to (3), an increase in the axial size of the torque converter A1 with the lockup clutch as a whole can be avoided, and good vehicle mountability can be ensured.

(5) Slip rings 10 and 10 for applying a current to the electromagnetic coil 54 are provided on the rotary shaft portion 9 of the pump impeller 1 including the output shaft 8;
The electromagnetic coil 54 is provided on the converter cover 7 connected to the pump impeller 1.
Therefore, in addition to the effects (1) to (4), the slip rings 10 and 10 and the electromagnetic coil 54 can be electrically connected with a simple configuration in which only one set of slip rings 10 and 10 is provided. .

  The second embodiment is an example of a normally closed MR fluid clutch that is in a lock-up fastening state when the energization of the electromagnetic coil is cut off.

First, the configuration will be described.
FIG. 4 shows a torque converter A2 with a lock-up clutch according to the second embodiment. The overall configuration will be described below with reference to FIG.
As shown in FIG. 4, the torque converter A2 with a lockup clutch includes a pump impeller 1, a turbine runner 2, a stator 3, an MR fluid 4, an MR fluid clutch 5, a permanent magnet 59, and a clutch control circuit. 60.

  The permanent magnet 59 generates a predetermined magnetic field with respect to the MR fluid layer 53 by a magnetic force line in a direction determined by the relationship between the N pole and the S pole, and as shown in FIG. Placed in position. That is, the permanent magnet 59 is disposed at a position radially inside the MR fluid layer 53 and sandwiched between the first flange portion 57 and the electromagnetic coil 54.

The clutch control circuit 60 is connected to the electromagnetic coil 54 and controls the flow direction of the coil current and the magnitude of the coil current with respect to the electromagnetic coil 54 based on input information. Here, the direction in which the coil current flows is defined as (+) on the side where the magnetic lines of force in the same direction as the direction of the magnetic lines of force by the permanent magnet 59 is formed, and (−) on the side of forming the magnetic lines of force in the direction opposite to the direction of magnetic lines of force by the permanent magnet 59. And
Since other configurations are the same as those in FIG. 1 of the first embodiment, the same reference numerals are given to the drawings and description thereof is omitted.

Next, the torque transmission capacity control action of the MR fluid clutch 5 by the clutch control circuit 60 of the second embodiment will be described with reference to FIG.
First, when energization to the electromagnetic coil 54 is made zero, a predetermined magnetic field is generated by a magnetic field line in a direction determined by the relationship between the N pole and the S pole of the permanent magnet 59, and MR is generated according to the magnetic field generated by the permanent magnet 59. Torque is transmitted through the MR fluid clutch 5 by changing the viscosity of the fluid layer 53 (normally closed).
Therefore, torque transmission through the MR fluid clutch 5 is ensured even if the electrical system to the electromagnetic coil 54 is broken.

Then, when the (+) side energization to the electromagnetic coil 54 is gradually increased, the magnetic field lines by the electromagnetic coil 54 are added to the magnetic field lines by the permanent magnet 59, and the MR fluid layer according to the magnetic field generated by the added magnetic field lines. As the viscosity of 53 increases, the torque transmitted via the MR fluid clutch 5 also increases.
Therefore, if the (+) side energization to the electromagnetic coil 54 is gradually increased, the torque transmission capacity via the MR fluid clutch 5 can be increased (torque addition section in FIG. 5).

Furthermore, when the (−) side energization to the electromagnetic coil 54 is gradually increased, the magnetic lines of force generated by the electromagnetic coil 54 are generated in a direction opposite to the magnetic lines of force of the permanent magnet 59, and the magnetic field generated by the subtracted magnetic lines of force is generated. Accordingly, the torque transmitted through the MR fluid clutch 5 also decreases as the viscosity of the MR fluid layer 53 decreases. When the (−) side energization is performed so that the absolute value of the magnetic field lines generated by the electromagnetic coil 54 coincides with the magnetic field lines generated by the permanent magnet 59, the two magnetic field lines cancel each other, and the MR fluid clutch 5 enters the lockup release state.
Accordingly, if the (−) side energization to the electromagnetic coil 54 is gradually increased, the torque transmission capacity via the MR fluid clutch 5 can be reduced (torque reduction section in FIG. 5), and the MR fluid clutch. 5 can be a lock-up release.
Since other operations are the same as those of the first embodiment, description thereof is omitted.

Next, the effect will be described.
In the torque converter A2 with the lock-up clutch of the second embodiment, the following effects can be obtained in addition to the effects (1) to (5) of the first embodiment.

(6) A permanent magnet 59 that generates a predetermined magnetic field with respect to the magnetorheological fluid layer (MR fluid layer 53) at a radially inner position of the magnetorheological fluid layer (MR fluid layer 53) together with the electromagnetic coil 54. Arranged.
For this reason, even if energization to the electromagnetic coil 54 is made zero, the normally closed MR fluid clutch 5 that ensures torque transmission via the MR fluid clutch 5 can be obtained.

(7) A clutch control circuit 60 for controlling the flow direction of the coil current and the magnitude of the coil current is connected to the electromagnetic coil 54.
For this reason, in addition to the effect of (6), it is possible to obtain a lockup release function by the MR fluid clutch 5, and to achieve an increase function and a decrease function of the torque transmission capacity via the MR fluid clutch 5.

  As mentioned above, although the torque converter with a lockup clutch of this invention has been demonstrated based on Example 1 and Example 2, it is not restricted to these Examples about a concrete structure, Each of Claims Design changes and additions are permitted without departing from the scope of the claimed invention.

  In the first and second embodiments, the MR fluid clutch 53 extends as six layers along the plane orthogonal to the converter rotation axis CL as the MR fluid clutch 5. However, the MR fluid clutch may be an example in which the MR fluid layer extends other than 6 layers (1 to 5 layers, 7 layers or more) along a plane orthogonal to the converter rotation axis. Further, the MR fluid layer may be a single layer or a multilayer extending along a cylindrical surface centering on the converter rotation axis.

  In the first and second embodiments, the first disk 51 of the MR fluid clutch 5 is provided in the first flange portion 57, and the second disk 52 of the MR fluid clutch 5 is provided in the second flange portion 58, thereby increasing the size in the radial direction. An example to avoid this is shown. However, when the increase in the radial size is not required, the MR fluid clutch may be an example of setting the outer diameter position of the pump impeller or the turbine runner.

  In the first and second embodiments, an example in which the yoke portion 55 is provided integrally with a part of the converter cover 7 is shown. However, the converter cover and the yoke portion may be provided separately.

  In the first embodiment, an example in which the torque converter with a lock-up clutch of the present invention is applied to an electric vehicle (hybrid vehicle, electric vehicle, etc.) having no hydraulic system has been shown. However, the torque converter with a lock-up clutch of the present invention can be applied not only to an electric vehicle but also to other vehicles such as an engine vehicle.

A1, A2 Torque converter 1 with lock-up clutch 1 Pump impeller 2 Turbine runner 3 Stator 4 MR fluid (magnetic viscous fluid)
5 MR fluid clutch 51 First disk 52 Second disk 53 MR fluid layer (magnetoviscous fluid layer)
54 Electromagnetic coil 55 Yoke part 56 Clutch control circuit 57 First flange part 58 Second flange part 59 Permanent magnet 60 Clutch control circuit

Claims (6)

A lock-up clutch having a pump impeller coupled to an input shaft via a converter cover, a turbine runner disposed opposite to the pump impeller and coupled to an output shaft, and a magnetorheological fluid sealed inside Is a torque converter with a lock-up clutch configured by an MR fluid clutch using a magnetorheological fluid,
A first disk coupled to the pump impeller;
A second disk coupled to the turbine runner;
An electromagnetic coil that generates a magnetic field by energizing a magnetorheological fluid layer formed between the disk-facing surfaces of the first disk and the second disk;
The electromagnetic coil is disposed at a radially inner position of the magneto-rheological fluid layer that generates a transmission torque according to a viscosity change caused by a magnetic field ,
Each of the first disk and the second disk has a multi-layer disk structure with a donut shape,
A torque converter with a lock-up clutch, wherein the magnetorheological fluid layer is formed in a plurality of layers so as to extend along a plane orthogonal to the converter rotation axis . The torque converter with a lock-up clutch according to claim 1 ,
An inner peripheral end portion of the first disk is provided on an outer peripheral surface of a first flange portion extending in the axial direction from the converter cover toward the turbine runner,
With the lock-up clutch, the outer peripheral end portion of the second disk is provided on the inner peripheral surface of the second flange portion extending in the axial direction from the outer peripheral end portion of the pump impeller toward the converter cover. Torque converter. The torque converter with a lock-up clutch according to claim 2 ,
A region of the converter cover in which the magneto-rheological fluid layer is formed is a yoke part that constitutes a magnetic circuit by a magnetic force line path,
The torque converter with a lockup clutch, wherein the electromagnetic coil is disposed at an inner peripheral side position of the first flange portion, and an outer peripheral portion excluding the first flange portion is surrounded by the yoke portion. . In the torque converter with a lock-up clutch according to any one of claims 1 to 3 ,
A slip ring for applying a current to the electromagnetic coil is provided on a rotary shaft portion of the pump impeller including the output shaft,
A torque converter with a lock-up clutch, wherein the electromagnetic coil is provided in the converter cover connected to the pump impeller. In the torque converter with a lock-up clutch according to any one of claims 1 to 4 ,
A torque converter with a lock-up clutch, wherein a permanent magnet that generates a predetermined magnetic field with respect to the magnetorheological fluid layer is disposed together with the electromagnetic coil at a radially inner position of the magnetorheological fluid layer. The torque converter with a lock-up clutch according to claim 5 ,
A torque converter with a lockup clutch, wherein a clutch control circuit for controlling a flow direction of the coil current and a magnitude of the coil current is connected to the electromagnetic coil.