DE10324487A1 - Electro-magnetically opened pole friction clutch has an exciter coil surrounded by a soft magnetic matrerial - Google Patents

Abstract

An electro-magnetically operated pole friction clutch (5) has a permanent magnet (1) that effects a link between an anchor (2) and the poles (3, 4). When activated a coil (6) negates the force between the anchor and clutch, interrupting torque transmission. The exciter coil (6) is enveloped by a soft-magnetic field (7) originating from fixed magnetic housing (8), a moving clutch (5) with poles (3,4) and anchor (2). A permanent magnet (1) is located in the immediate vicinity of the two poles (3, 4) and generates a magnetic flux (13).

Description

Electromagnetically opening Pole friction clutches have the task of torque from a drive to transfer to an output. In order to meet safety requirements, the coupling must Switch off the power or close in the event of a power failure. At the closing the drive is non-positively connected to the output and by friction transfer the input speed to the output. The non-positive connection is generated by permanent magnets, whose magnetic flux is the armature at the magnetic poles under the effect of the magnetic force. As a result of the contact pressure between the poles and the armature is under Influence of the coefficient of friction a torque generates to drive Loads on the output side of the clutch. When turning on the power the magnetic field of the permanent magnet is caused by the electromagnetic field deflected the excitation coil so that the armature lifts off the poles and hence the torque transmission will be annulled.

Permanent magnet, electromagnetic pole friction brakes based on the same physical Principle work has long been known. It is obvious from derive such a clutch, using the same principle is working. The problem is that with the clutch a torque from one rotatable part to a second rotatable part Transfer part is. The pole friction brake has only one rotating part, in usually the anchor on which the braking torque occurs, the Excitation coil and the permanent magnet are arranged stationary. The two rotating parts, the drive part and the driven part the clutch from the excitation system, the stationary one Part, separated by air gaps. These parasitic air gaps weaknesses the magnetic flux in such a way that the coupling is significantly lower Torque than occurs with the brake.

task The innovation is to eliminate this disadvantage by using the permanent magnet in a clutch body is integrated and rotates with the drive or driven side. As a result, the permanent magnet comes into full effect, i.e. the magnetic flux is not caused by parasitic Air gaps weakened. This has a far higher one Coupling torque result.

The functionality of the innovation is based on the 1 to 5 explained.

1 shows the structure with the clutch closed.

The anchor ( 2 ) is used by the Poles ( 3 ) ( 4 ) by the magnetic flux ( 13 ) of the permanent magnet ( 1 ) so that between the drive ( 11 ) and downforce ( 12 ) a torque is transmitted. The rotating coupling body ( 5 ) carries the permanent magnet ( 1 ) and includes the poles ( 3 ) ( 4 ) the magnetic flux ( 13 ) over the anchor ( 2 ) transmits the drive torque to the output due to friction ( 12 ) transmits. The excitation coil ( 6 ) with soft magnetic parts as a magnetic circuit ( 7 ) enclosed. The air gap ( 9 ), ( 10 ) ensure that the excitation coil ( 6 ) and the magnet housing ( 8th ) can be arranged stationary and centrally. If the clutch is set up as a brake, the clutch body ( 5 ) also arranged stationary. In 1 For example, the centering of the magnet housing ( 8th ) from the bearing bush ( 15 ) accepted.

2 shows the clutch open.

The anchor ( 2 ) is used by the Poles ( 3 ) ( 4 ) not attracted, because of positive directional energization of the excitation coil ( 6 ) the magnetic flux ( 13 ) of the permanent magnet ( 1 ) from magnetic flux ( 14 ) the excitation coil ( 6 ) is deflected and not over the anchor ( 2 ) flows. Drive ( 11 ) and downforce ( 12 ) are freely rotatable and cannot transmit any torque because the poles ( 3 ) ( 4 ) and anchor ( 2 ) through the air gap ( 19 ) are spaced.

Definition:

Positive directional energization: through the excitation coil ( 6 ) becomes a magnetic flux ( 14 ) which generates the magnetic flux ( 13 ) of the permanent magnet ( 1 ) from the Poles ( 3 ) ( 4 ) leads away.

Negative directional energization: Through the excitation coil ( 6 ) becomes a magnetic flux ( 14 ) which, together with the magnetic flux ( 13 ) of the permanent magnet ( 1 ) over the poles ( 3 ), ( 4 ) flows through the anchor.

3 shows the closed clutch, with the excitation coil ( 6 ) is energized in the negative direction to amplify the torque.

In the poles ( 3 ) ( 4 ) and anchor ( 2 ) the magnetic fluxes add up ( 13 ) and ( 14 ) so that a greater pull force on the anchor ( 2 ) acts and thereby the torque is increased. The anchor ( 2 ) is via the preloaded spring device ( 16 ) for example with axially movable leaf springs on the hub ( 17 ) attached, for torsionally stiff transmission of the coupling torque from the drive ( 11 ) on the downforce ( 12 ).

4 shows the attachment of the anchor ( 2 ) with the hub ( 17 ) via the spring device ( 16 ) through the rivets ( 18 ). In this exemplary case, the spring device ( 16 ) made of preloaded and axially movable leaf springs. To transmit the torque without play, the leaf springs are arranged tangentially to the direction of rotation. Is the preload ( 20 ) the spring device ( 16 ) selected greater than the magnetic force generated by the magnetic flux ( 13 ) of the permanent magnet ( 1 ) with the clutch open, then four switching states can be realized with the clutch, as from 5 seen.

5 shows the four switching states 1. to 4. of the clutch, the torque ( 21 ) the coupling via the current of the excitation coil ( 6 ) is applied. The four switching states are described in detail in claim 8.

It is irrelevant whether the speed of the drive ( 11 ) in the downforce ( 12 ) is initiated or vice versa. The functions are not affected by this. It is conceivable, on or between the friction surfaces of the poles ( 3 ) and ( 4 ) Arrange friction linings to improve the friction properties of the clutch.

The permanently excited, electromagnetic pole friction clutch can be regarded as a special case of a brake. The innovation can therefore also be used as a permanently excited, electromagnetic pole friction brake if the clutch body ( 5 ) together with the magnet housing ( 8th ) is stationary. The brake is used to stop and hold static and dynamic loads, via the anchor ( 2 ) with the output ( 12 ) is axially movable but non-rotatably connected. In this case, the output ( 12 ) to drive ( 11 ).

Definition:

Positive directional energization: through the excitation coil ( 6 ) becomes a magnetic flux ( 14 ) which generates the magnetic flux ( 13 ) of the permanent magnet ( 1 ) from the Poles ( 3 ) ( 4 ) repressed.

Negative directional energization: Through the excitation coil ( 6 ) becomes a magnetic flux ( 14 ) which, together with the magnetic flux ( 13 ) of the permanent magnet ( 1 ) over the poles ( 3 ), ( 4 ) flows through the anchor.

1

permanent magnet

2

anchor

3

pole (Outer pole)

4

pole (Inner pole)

5

clutch body

6

excitation coil

7

magnetic circuit

8th

magnet housing

9

air gap (Outside)

10

air gap (Inside)

11

drive

12

output

13

magnetic flux (Permanent magnet)

14

magnetic flux (Exciting coil)

15

bearing bush

16

spring means (Leaf spring)

17

hub

18

rivet

19

Air gap between anchor ( 2 ) and Pole ( 3 ) ( 4 )

20

preload force the spring device

21

Anchor force ( 2 ) to the poles ( 3 ) ( 4 ) or torque of the clutch as a function of the current

F

Magnetic force, spring force

I

electricity

I _N

current

M

torque the clutch

M _N

rated torque the clutch

Claims (8)

Electromagnetically opening friction clutch created by the magnetic force generated by a permanent magnet ( 1 ), a frictional connection between an anchor ( 2 ) and the Poles ( 3 ) and ( 4 ) of the coupling body ( 5 ) generated for the transmission of a torque by friction and with positive directional energization of an excitation coil ( 6 ) the magnetic force between armature ( 2 ) and the coupling body ( 5 ), whereby the torque transmission is interrupted, characterized in that an excitation coil ( 6 ) of a soft magnetic material as a magnetic circuit ( 7 ) is enclosed, which consists of a stationary magnet housing ( 8th ), a rotating coupling body ( 5 ) with the Poles ( 3 ) and ( 4 ), an axially movable and with the output ( 12 ) positively connected anchors ( 2 ) exists between and in the immediate vicinity of the two poles ( 3 ) and ( 4 ) a permanent magnet ( 1 ) is arranged in the direction of magnetization, which is a magnetic flux ( 13 ) generated. Electromagnetically opening pole friction clutch according to claim 1, characterized in that the permanent magnet ( 1 ) in the rotating coupling body ( 5 ) is integrated. Electromagnetically opening pole friction clutch according to claim 1 and 2, characterized in that a rotatable coupling body ( 5 ) from the fixed magnet housing ( 8th ) due to air gaps ( 9 ) ( 10 ) is separated. Electromagnetically opening pole friction clutch according to claim 1 to 3, that the load moments to be transmitted by the coupling on an anchor ( 2 ) or coupling body ( 5 ) via an output ( 12 ) or drive ( 11 ) or vice versa. Electromagnetically opening pole friction clutch according to claim 1 to 4, characterized in that a clutch body ( 5 ) and magnetic housing ( 8th ) is constructed and arranged in such a way that when the excitation coil is energized ( 6 ) with negatively directed current the magnetic flux ( 14 ) the excitation coil ( 6 ) and that of the permanent magnet ( 1 ) together over the poles ( 3 ) ( 4 ) and anchor ( 2 ) flow. Electromagnetically opening pole friction clutch according to claim 1 to 5, characterized in that a clutch body ( 5 ) and magnetic housing ( 8th ) is constructed and arranged in such a way that when the excitation coil is energized ( 6 ) with positively directed current the magnetic flux ( 14 ) the excitation coil ( 6 ) and the magnetic flux ( 13 ) of the permanent magnet ( 1 ) together via the permanent magnet ( 1 ) and the magnet housing ( 8th ) flow. Electromagnetically opening pole friction clutch according to claim 1 to 6, characterized in that a clutch body ( 5 ) and magnetic housing ( 8th ) is arranged such that when the excitation coil is de-energized ( 6 ) the magnetic flux ( 13 ) of the permanent magnet ( 1 ) essentially over the poles ( 3 ) ( 4 ) and the anchor ( 2 ) flows. Electromagnetically opening pole friction clutch according to claim 1 to 7, characterized in that the biasing force of the spring device ( 16 ) is greater than the magnetic force generated by the magnetic flux ( 13 ) of the permanent magnet ( 1 ) with the clutch open to generate four switching states, namely: - a first, de-energized state, in which the spring device ( 16 ) the anchor ( 2 ) spaced from the poles ( 3 ) ( 4 ) holds, - a second one, in the case of negative directional energization with an adequately dimensioned nominal current I _{N, can} be energized so that the air gap ( 19 ) is overcome, - a third party, in which the energization of the excitation coil ( 6 ) is switched off and the force of the permanent magnet ( 1 ) the anchor at the poles ( 3 ) ( 4 ) against the force of the spring device ( 16 ) holds, and - a fourth which, when the excitation coil is energized briefly for a short time ( 6 ) arises so that the anchor ( 2 ) again from the Poles ( 3 ) ( 4 ) against the force of the permanent magnet ( 1 ) and supportive by the force of the spring device ( 16 ) returned to its rest position.