CN111379800A

CN111379800A - Torque transmitting device

Info

Publication number: CN111379800A
Application number: CN201811628946.7A
Authority: CN
Inventors: 刁桂源; 黄敬修
Original assignee: Logistics and Supply Chain Multitech R&D Centre Ltd
Current assignee: Logistics and Supply Chain Multitech R&D Centre Ltd
Priority date: 2018-12-28
Filing date: 2018-12-28
Publication date: 2020-07-07

Abstract

The invention discloses a torque transmission apparatus, comprising: a fixing member; a movable member movable in a first direction relative to the fixed member; a cavity defined between the fixed member and the movable member for holding a fluid transitionable between a default physical state during which the fluid exerts a force on the movable member in a second direction opposite the first direction and a temporary physical state during which the force exerted on the movable member is reduced in response to the application of a temporary magnetic flux.

Description

Torque transmitting device

Technical Field

The present invention relates generally to a torque transmitting apparatus and, more particularly, although not exclusively, to a torque transmitting apparatus having a movable member movable in a first direction and a fluid exerting a force on the movable member in a second direction opposite the first direction.

Background

Torque transmitting devices, such as brakes and clutches, typically employ relatively rotatable members that are frictionally engaged to absorb and transfer kinetic energy. They generally involve mechanical transmission of the vehicle. For example, when a driver shifts gears to change the speed and power of the vehicle, the clutch is typically used to engage or disengage the mechanical transmission from the engine to the wheels of the vehicle, while the brake is typically used to decelerate or stop the vehicle in an abrupt manner when the driver first depresses a clutch pedal, which then depresses a brake pedal that cuts off the supply of power from the engine to the transmission of the vehicle, from its initial position. However, during braking or operating the clutch, the contacting components are subject to wear, and in the long term, the critical components wear. Therefore, the mechanical transmission device requires frequent maintenance.

Disclosure of Invention

To address or reduce at least some of the disadvantages associated with conventional torque transmitting devices, a torque transmitting device is disclosed that includes a cavity for holding a fluid transitionable between two physical states in response to application of a magnetic flux.

The present invention provides a torque transmitting apparatus comprising: a fixing member; a movable member movable in a first direction relative to the fixed member; a cavity defined between the fixed member and the movable member for holding a fluid transitionable between a default physical state during which the fluid exerts a force on the movable member in a second direction opposite the first direction and a temporary physical state during which the force exerted on the movable member is reduced in response to the application of a temporary magnetic flux.

In one embodiment, the fluid remains in a default physical state in response to a default magnetic flux being applied thereto.

In one embodiment, the torque transmitting device further comprises a magnetic adjustment mechanism for manipulating the default magnetic flux to transition the fluid between the default physical state and the temporary physical state.

In one embodiment, the magnetic adjustment mechanism manipulates the position of the default magnetic flux.

In one embodiment, the magnetic adjustment mechanism manipulates the strength of the default magnetic flux.

In one embodiment, the magnetic adjustment mechanism includes a first magnetic source for applying a default magnetic flux to maintain the fluid in a default physical state.

In one embodiment, the magnetic adjustment mechanism further comprises a second magnetic source for applying the temporary magnetic flux, the default magnetic flux interacting with the temporary magnetic flux to transform the fluid into the temporary physical state.

In one embodiment, the temporary magnetic flux biases the default magnetic flux away from the fluid.

In one embodiment, the default magnetic flux opposes the temporary magnetic flux to cancel the default magnetic flux applied to the fluid.

In one embodiment, the default physical state comprises a solid state.

In one embodiment, the temporary physical state includes one of a liquid state and a gaseous state.

In one embodiment, the first magnetic source comprises a permanent magnet.

In one embodiment, the second magnetic source comprises an electrical coil.

In one embodiment, the viscosity of the fluid is controlled by the magnetic adjustment mechanism.

In one embodiment, the fluid comprises a magnetorheological fluid.

In one embodiment, the stationary member is a stator and the movable member is a rotor rotatable relative to the stator.

Drawings

Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 illustrates a torque transmitting device according to one embodiment of the present invention;

FIG. 2 is a side view of the torque transmitting device of FIG. 1, showing axis A-A, according to one embodiment of the present invention;

FIG. 3 is a top view of the torque transmitting device of FIG. 1 in accordance with one embodiment of the present invention;

FIG. 4 is a bottom view of the torque transmitting device of FIG. 1 in accordance with one embodiment of the present invention;

FIG. 5 is an exploded view of the torque transmitting device of FIG. 1 in accordance with one embodiment of the present invention;

FIG. 6 is a cross-sectional view of the torque transmitting device of FIG. 2 along axis A-A, according to one embodiment of the present invention;

FIG. 7 is an enlarged cross-sectional view of the torque transmitting device of FIG. 6 in accordance with an embodiment of the present invention;

FIG. 8 is a schematic cross-sectional view of a torque transmitting device in response to application of a default magnetic flux in accordance with an embodiment of the present invention; and

FIG. 9 is another schematic cross-sectional view of a torque transmitting device in response to application of a temporary magnetic flux in accordance with an embodiment of the present invention.

Detailed Description

Without being bound by theory, the inventors have devised, through their own experiments and experiments: although Magnetorheological (MR) fluids are suitable for mechanical transmission applications, such active braking systems are triggered by an electric current induced magnetic field and are therefore somewhat unsafe when the power supply is unstable.

Referring initially to fig. 1-9, a torque transmitting device 100 is provided, including: a fixed member 10, a movable member 30 movable in a first direction relative to the fixed member 10; a cavity 40 defined between the stationary member 10 and the movable member 30 for holding the fluid 42 transitionable between a default physical state during which the fluid 42 exerts a force on the movable member 30 in a second direction opposite to the first direction and a temporary physical state during which the force exerted on the movable member 30 is reduced in response to the application of the temporary magnetic flux 55.

The torque transmitting device 100 may be integrated as a brake or a clutch. Referring to fig. 1-9, in the present invention, the torque transmitting device is embodied as a brake 100. However, without departing from the concept of the invention, it will be understood by those skilled in the art that the following description and embodiments may be applied in any other application, for example in a clutch with minor modifications.

Referring to fig. 1-4, a brake 100 is provided that may be used with a movable device or apparatus, such as a vehicle, boat, or airplane, for example. The brake 100 includes: a stationary housing 110 defined by a housing cover 112 and a housing main body 114; and a rotatable shaft 20 housed within the housing 110, preferably in the center of the housing 110. The shaft 20 may extend through the housing cover 112 along the rotational axis 22 and may be connected to a wheel (not shown) of the vehicle such that varying the movement of the shaft 20 may in turn vary the movement of the wheel.

Turning now to fig. 5-7 with respect to the detailed internal structure, brake 100 further includes: a fixing member 10 forming a part of the housing 110; the movable member 30 is movable relative to the fixed member 10, wherein the movable member 30 is actuated by the shaft 20; and a cavity 40 is defined between the fixed member 10 and the movable member 30 for retaining a fluid 42 therein.

In one embodiment, the stationary member 10 may be an additional member surrounded by the housing 110 serving as a stator, and the movable member 30 may be positioned within the stationary member 10, the stationary member 10 serving as a rotor rotatable with respect to the stator 10. The movable member 30 may include a disc 32 and a drum 34 for receiving mechanical transmission from the shaft 20. The shaft 20 may be connected to the rotor 30 via a shaft key 36, by which shaft key 36 the shaft 20 may actuate the rotor 30 in response to actuation of the engine.

In one embodiment, brake 100 is further provided with a magnetic adjustment mechanism 50, preferably adjacent fluid 42 held in cavity 40, for adjusting the magnetic flux interacting with fluid 42. The magnetic adjustment mechanism 50 may include two magnetic sources, the cooperation of which may selectively apply magnetic flux to the fluid 42 during different phases. In the illustrated embodiment, the two magnetic sources may include a permanent magnet 52 and an electrical coil 54. Both the permanent magnets 52 and the electrical coils 54 are preferably annular and arranged within the rotor 30 such that the permanent magnets 52 and the electrical coils 54 are positioned annularly around the rotor 30.

In one exemplary embodiment, permanent magnet 52 is shown having a larger diameter than electrical coil 54, such that permanent magnet 52 is positioned between fluid 42 and electrical coil 54, and is positioned closer to fluid 42 than electrical coil 54. The illustrated permanent magnet 52 has a shorter height than the electrical coil 54 in order to provide a magnetic flux 53 of suitable strength. Alternatively, permanent magnets 52 having different heights or sizes may be utilized depending on the desired strength of the magnetic flux 53 to be applied to the fluid 42, as understood by those skilled in the art.

For a detailed description of the working principle of the magnetic adjustment mechanism 50, finally with reference to fig. 8 and 9, the fluid 42 held in the cavity 40 can be switched between two physical states: between the first default physical state and the second physical state, in the first default physical state, high friction is applied between the stator 10 and the rotor 30, and in the second physical state, if no friction is applied between the stator 10 and the rotor 30, there is almost minimal friction.

When a default magnetic flux 53 is applied to the fluid 42 by the permanent magnets 52, the fluid 42 remains in a default physical state, causing the fluid 42 to exert a significant force on the rotor 30 in a direction opposite the direction of rotation of the rotor 30, as shown in fig. 8. Thus, if the vehicle is currently being driven by the engine, the wheels of the vehicle remain stationary or slow down.

When electrical coils 54 apply a temporary magnetic flux 55 to fluid 42, as shown in FIG. 9, fluid 42 is transformed into a temporary physical state, thereby at least reducing the amount of force exerted on rotor 30, or reducing the force to a negligible amount, i.e., no friction.

To manipulate the physical state of fluid 42, a default magnetic flux 53 is maintained by permanent magnet 52, while a temporary magnetic flux 55 is selectively generated by electrical coil 54. Preferably, the fluid 42 is a magnetorheological fluid containing a suspension of magnetizable particles in a carrier 42. When subjected to the default magnetic flux 53 generated by the permanent magnet 52, the magnetorheological fluid 42 increases its apparent viscosity and becomes a viscoelastic solid. By varying the magnetic field strength, the yield stress of the fluid 42 can be precisely controlled so that engagement and disengagement between the stator 10 and the rotor 30 can occur gradually.

The default flux 53 is manipulated by the permanent magnet 52; the temporary magnetic flux 55 is manipulated by an electric coil 54. Permanent magnet 52 is positioned between fluid 42 and electrical coil 54, creating a default magnetic flux 53 that in turn transforms fluid 42 into a solid state in a default state, without current passing through electrical coil 54. When an electrical current is passed through electrical coil 54 (i.e., when power is supplied to brake 100), a temporary magnetic flux 55 is generated, which in turn converts fluid 42 into a liquid or gas state in a temporary state.

In other words, in a default state where no power is supplied to brake 100, electrical coil 54, fluid 42 are thus maintained in a solid state, and brake 100 acts as a means of inhibiting movement of the moving system (e.g., a vehicle) so that the moving system is stationary. When the motion system needs to be moved, the user may power the brake 100, for example, by depressing a pedal, thereby converting the fluid 42 into a liquid or gas and disabling the braking function.

As shown in fig. 8, magnetic field lines of the default magnetic flux 53 are generated by the permanent magnet 52. The default magnetic flux 53 has an effect on the physical state of the fluid 42 held in the cavity 40, thereby changing the physical state of the fluid 42 and maintaining the fluid 42 in a solid state. However, as shown in FIG. 9, when an electrical current is supplied to electrical coil 54, temporary magnetic flux 55 has an effect on the physical state of fluid 42 held in cavity 40, thereby temporarily changing the physical state of fluid 42 and converting fluid 42 into a liquid or gaseous state.

In one embodiment, the permanent magnet 52 and the electric coil 54 manipulate the position of the default magnetic flux 53. The induced current creates a temporary magnetic field 55 that changes the position of the default magnetic flux 53 by moving the default magnetic flux 53 away from the fluid 42. Thus, the default magnetic flux 53 no longer interacts with the fluid 42, and the fluid 42 is thus converted to a liquid or gaseous state.

In an alternative embodiment, the permanent magnet 52 and the electric coil 54 manipulate the strength of the default magnetic flux. When an electric current is passed through the electric coil 54, the temporary magnetic flux 55 generated by the electric coil 54 generally has a greater intensity than the intensity of the default magnetic flux 53 generated by the permanent magnet 52. Thus, the weaker default magnetic flux 53 opposes the stronger temporary magnetic flux 55, thereby eliminating the default magnetic flux 53 exerted on the fluid 42. Thus, the effect of the fluid 42 is produced. The default magnetic flux 53 on the fluid 42 is masked by the influence of the stronger temporary magnetic flux 55, so that the fluid 42 in the solid state becomes liquid or gaseous when power is supplied to the electrical coil 54.

In yet another embodiment, the torque transmitting device 100 may be embodied as a clutch (not shown) that may be used in an engine as an automotive clutch to separate a driveshaft (i.e., the flywheel of the engine) from a driveshaft in a vehicle. The clutch plays a crucial role in decoupling the engine from the mechanical transmission, so that no torque is transmitted and the driver can shift gears easily. The clutch may also be used as a brake or as a reduction on the drive shaft by fixing the drive shaft against rotation.

In this embodiment, the principle of operation of the clutch is very similar to that of the brake 100 described above. In the clutch mechanism, two rotating shafts are provided, one of which is a driving shaft and the other of which is a driven shaft. The clutch allows selective coupling and decoupling of the two shafts by positioning one shaft adjacent the other shaft separated by the MR fluid containment cavity. The shafts may be coupled together to rotate at the same speed, partially coupled to rotate at different speeds, or completely decoupled, depending on the state of the fluid located between the shafts.

In a default state where no current is applied to the clutch, the fluid in the cavity between the two shafts is in a default physical state (i.e., solid state) due to the presence of a default magnetic flux generated by the permanent magnet. When the two shafts are brought into contact with each other by the coagulated MR fluid, they rotate as a single unit, so that the rotational motion of the drive shaft is transmitted to the driven shaft.

Before the driver shifts gears, he initially depresses the pedal and induces an electric current to generate a temporary magnetic flux via the electric coil, manipulating the default magnetic flux to interact with the temporary magnetic flux generated by the electric coil, thereby temporarily changing the physical state of the fluid from a solid state to a liquid or gaseous state. This in turn disengages the mechanical transmission of the two shafts so that the driven shaft does not rotate with the drive shaft, thereby allowing the gears to move to change the speed and power of the vehicle.

When the driver is satisfied with the speed and/or power of the vehicle and does not want to further change the transmission ratio, the driver can release the pedal and interrupt the current applied to the clutch, thereby restoring the default magnetic flux, and thus restoring the physical state of the fluid from a temporary liquid or gas state to a solid state. As a result, the driven shaft will rotate with the drive shaft and engage the mechanical transmission of the two shafts.

As described above, the present invention provides a torque transmitting device 100 (e.g., a brake or clutch) that has safer operation than conventional torque transmitting devices that function when powered. This is particularly useful when experiencing a fault or insufficient power in a moving system (e.g., a vehicle). In the case of using a conventional electromagnetic brake, when a driver wants to decelerate or stop the vehicle by applying current to the brake, the vehicle to which the brake is connected may continue to move. This is dangerous, especially when the vehicle is on an inclined slope. On the other hand, as described herein, the present torque transmitting device may still function normally to prevent movement of the vehicle as needed in the presence of power shortages and no current applied to the brakes.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Unless otherwise indicated, any reference to prior art contained herein is not to be taken as an admission that the information is common general knowledge.

Claims

1. A torque transmitting device comprising:

a fixing member;

a movable member movable in a first direction relative to the fixed member;

a cavity defined between the stationary member and the movable member for holding a fluid transitionable between a default physical state during which the fluid exerts a force on the movable member in a second direction opposite the first direction and a temporary physical state during which the force exerted on the movable member is reduced in response to the application of a temporary magnetic flux.

2. The torque transmitting device as recited in claim 1 wherein the fluid remains in the default physical state in response to a default magnetic flux being applied thereto.

3. The torque transmitting device as recited in claim 2 further comprising a magnetic adjustment mechanism for manipulating said default magnetic flux to transition said fluid between said default physical state and said temporary physical state.

4. The torque transmitting apparatus as recited in claim 3 wherein the magnetic adjustment mechanism manipulates the position of a default magnetic flux.

5. The torque transmitting device as claimed in claim 3, wherein the magnetic adjustment mechanism manipulates the strength of the default magnetic flux.

6. The torque transmitting apparatus as recited in claim 3 wherein said magnetic adjustment mechanism includes a first magnetic source for applying said default magnetic flux to thereby maintain said fluid in said default physical state.

7. The torque transmitting apparatus as recited in claim 6 wherein said magnetic adjustment mechanism further comprises a second magnetic source for applying said temporary magnetic flux, said default magnetic flux interacting with said temporary magnetic flux to thereby transform said fluid into said temporary physical state.

8. The torque transmitting device as recited in claim 7 wherein the temporary magnetic flux biases the default magnetic flux away from the fluid.

9. The torque transfer apparatus as claimed in claim 7 wherein the default magnetic flux opposes the temporary magnetic flux to cancel the default magnetic flux applied to the fluid.

10. The torque transmitting device as recited in claim 1 wherein the default physical state comprises a solid state.

11. The torque transmitting device as recited in claim 1, wherein the temporary physical state comprises one of a liquid state and a gaseous state.

12. The torque transmitting apparatus as set forth in claim 6, wherein said first magnetic source comprises a permanent magnet.

13. The torque transmitting apparatus as claimed in claim 7 wherein the second magnetic source comprises an electrical coil.

14. The torque transmitting apparatus as set forth in claim 3, wherein the viscosity of said fluid is controlled by said magnetic adjustment mechanism.

15. The torque transmitting device as recited in claim 1, wherein the fluid comprises a magnetorheological fluid.

16. The torque transmitting apparatus as claimed in claim 1, wherein the fixed member is a stator and the movable member is a rotor rotatable relative to the stator.