JPH0826906B2 - Magnetic particle type electromagnetic coupling device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic particle type electromagnetic coupling device that magnetizes magnetic particles to link a drive member and a driven member in a chain shape.

[Prior Art] FIG. 2 is a sectional view showing an example of a conventional magnetic particle type electromagnetic coupling device, in which (1) is a stator and (2).
Is an exciting coil built in this stator (1), (3)
Is a first bracket supported on the stator (1),
Also, the drive rotary shaft (6) is rotatably supported via the second bearings (4) and (5). (7) is a drive member which is fixed to the drive rotating shaft (6) and constitutes a first connecting main body provided inside the stator (1) with a predetermined gap, and (8) is a drive member (7). A plate fixed to the end of the drive member, (9) a driven member that constitutes a second connecting main body provided inside the drive member (7) via a predetermined radial annular gap, and (10) an annular gap Magnetic particles filled inside (11) are driven members (9)
And a driven rotary shaft fixed to the stator (1), the driven rotary shaft (11) fixed to the stator (1) is rotatably supported via third and fourth bearings (13) and (14). Second
It is a bracket.

(20) is the central axis of the drive rotary shaft (6), (21),
(22) is the first and second magnetic layers made of a high magnetic permeability soft magnetic material fixed on the outer peripheral surface of the drive rotating shaft (6),
The first magnetic layer (21) is formed in a counterclockwise direction of 45 ° and the second magnetic layer (22) is formed in a clockwise direction of 45 ° with respect to the central axis (20). (23) is a coil bobbin disposed inside the first bracket (3), and (24), (2
5) is the first and second detection coils wound around this coil bobbin (23), and (27) and (28) are provided around the first and second detection coils (24) and (25). The first and second magnetic flux concentrating layers are made of a high magnetic permeability magnetic material. (29)
Is a detection circuit connected to the first and second detection coils (24) and (25), and the detection circuit (29) is a well-known inductance differential amplifier circuit.

Next, the operation will be described. When the drive rotary shaft (6) coupled to a drive source (not shown) is rotated and the drive member (7) rotates integrally with the drive rotary shaft (6), an exciting coil built in the stator (1). When a current is applied to (2), a magnetic flux (Φ) is generated as shown by the dotted line in the figure. The magnetic particles (10) that are a part of the magnetic path are connected in a chain between the rotating drive member (7) and the stationary driven member (9), and the driven member (9) rotates. Then, the driven shaft (11) coupled to the load side (not shown) is rotated integrally with the driven member (9). Then, when the current of the exciting coil (2) is cut off, the magnetic flux (Φ)
Disappears, the chain-like connection of the magnetic particles (10) is broken, and the driven member (9) becomes free. The transmitted torque value is almost linearly proportional to the value of the current flowing through the exciting coil (2).

Here, in the state in which power is transmitted, torque for power transmission is applied to the drive rotating shaft (6), and one of the first and second magnetic layers (21) and (22) is applied. A tensile force is generated and a compressive force is generated on the other side, which causes strain. When this distortion occurs, the magnetic permeability changes, and the magnetic permeability changes in the opposite direction between the tensile force and the compressive force. The first and second detection coils (24) and (25) detect this change in permeability as a change in magnetic impedance, and a detection circuit (29).
Outputs differentially amplified outputs of the first and second detection coils (24) and (25) and outputs a detection voltage according to the amount of distortion of the drive rotation shaft (6), that is, the torque.

[Problems to be Solved by the Invention] In the magnetic particle type electromagnetic coupling device configured as described above, the drive rotating shaft (6) is made of carbon steel, and the magnetic flux (Φ) generated by the exciting coil (2) is generated. ′) Passes through the drive rotation shaft (6) as shown in the figure, so that its magnetic flux (Φ ′) passes through the first magnetic layer (21) and the second magnetic layer (22), There is a problem that the magnetic operating points of the first magnetic layer (21) and the second magnetic layer (22) move to cause a large error in the torque detection output.

The first invention and the second invention of the present invention have been made to solve the above problems, and an object thereof is to obtain a magnetic particle type electromagnetic coupling device capable of performing highly accurate and stable torque detection. .

[Means for Solving the Problems] A first invention according to the present invention comprises a rotating shaft provided with a magnetic layer made of a non-magnetic material.

According to a second aspect of the present invention, the rotating shaft provided with the magnetic layer is made of a material having a thermal expansion coefficient substantially equal to that of the magnetic layer.

[Operation] In the first aspect of the present invention, since the rotating shaft is made of a non-magnetic material, the magnetic flux generated by the exciting coil does not affect the magnetic layer.

Further, in the second aspect of the present invention, since the rotating shaft is made of a material having a coefficient of thermal expansion substantially equal to that of the magnetic layer, stress does not occur between the two due to temperature change.

Embodiment An embodiment of the present invention will be described below with reference to the drawings. First
The drawings show an embodiment of the first invention and the second invention of the present invention, and the same or corresponding parts as in FIG. 2 are denoted by the same reference numerals, and the description thereof will be omitted.

In the figure, (30) is a drive rotating shaft made of a non-magnetic material, for example, made of Hastelloy of Ni-base superalloy, and the thermal expansion coefficient of the drive rotating shaft (30) is made of amorphous first and second magnetic layers ( 21) and (22) are almost equal to the coefficient of thermal expansion
It is about 10-12 × 10 ^-6 .

In the magnetic particle type electromagnetic coupling device configured as described above, since the drive rotating shaft (30) is made of a non-magnetic material, the magnetic flux generated in the exciting coil (2) causes the drive rotating shaft (30) to rotate.
There is no adverse effect on the first and second magnetic layers (21) and (22) through the.

Further, there is almost no difference in thermal expansion between the drive rotation shaft (30) made of Hastelloy and the first and second magnetic layers (21) and (22) made of amorphous, and both (3
There is no stress between 0), (21) and (22).

In the above embodiment, the magnetic particle type electromagnetic continuous device in which the first magnetic layer (21) and the second magnetic layer are fixed to the drive rotating shaft (30) has been described. The magnetic layer (21) and the second magnetic layer (22) may be fixed.

In this case, the driven rotary shaft is made of Hastelloy.

Further, the present invention can also be applied to one in which the first magnetic layer is fixed to the drive rotation shaft and the second magnetic layer is fixed to the driven rotation shaft.

Further, although the invention applied to the magnetic particle type electromagnetic coupling device having the clutch function has been described in the above embodiment, the present invention provides a braking function which the driven rotary shaft does not have because the rotation of the drive rotary shaft is blocked by the driven member. It can also be applied to the magnetic particle type electromagnetic coupling device provided.

Furthermore, the drive rotary shaft (6) may be made of Inconel, for example.

[Effects of the Invention] As described above, according to the magnetic particle type electromagnetic coupling device of the first invention of the present invention, since the rotating shaft provided with the magnetic layer is made of a non-magnetic material, The magnetic layer is not affected by the generated magnetic flux,
Due to the influence, the magnetic operating point of the magnetic layer does not move, and it is possible to perform highly accurate and stable torque detection.

Further, according to the magnetic particle type electromagnetic coupling device of the second invention of the present invention, since the rotating shaft is made of a material having substantially the same thermal expansion coefficient as that of the magnetic layer, stress is not generated between them due to temperature change. Therefore, there is an effect that stable and highly accurate torque detection can be performed.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG. 2 is a sectional view showing an example of a conventional magnetic particle type electromagnetic coupling device. In the figure, (2) is an exciting coil, (7) is a drive member, (9) is a driven member, (10) is magnetic particles,
(11) is the driven rotary shaft, (21) is the first magnetic layer, (22)
Is a second magnetic layer, (24) is a first detection coil, (25) is a second detection coil, and (30) is a drive rotating shaft. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (2)

[Claims] 1. A drive member fixed to a driving rotary shaft, a driven member fixed to a driven rotary shaft, magnetic particles filled between the driven member and the drive member, and the magnetic particles. An exciting coil that is magnetized to connect the drive member and the driven member in a chain shape, a magnetic layer provided on an outer peripheral surface of at least one of the drive rotation shaft and the driven rotation shaft, and the magnetic layer. A magnetic particle type electromagnetic coupling device including a detection coil provided around the magnetic particle type electromagnetic coupling device, wherein a rotating shaft provided with the magnetic layer is made of a non-magnetic material. 2. A drive member fixed to a driving rotary shaft, a driven member fixed to a driven rotary shaft, magnetic particles filled between the driven member and the drive member, and the magnetic particles. An exciting coil that is magnetized to connect the drive member and the driven member in a chain shape, a magnetic layer provided on an outer peripheral surface of at least one of the drive rotation shaft and the driven rotation shaft, and the magnetic layer. In a magnetic particle type electromagnetic coupling device including a detection coil provided around the magnetic particle, the rotating shaft provided with the magnetic layer is made of a material having a thermal expansion coefficient substantially equal to that of the magnetic layer. Type electromagnetic coupling device.