JP2838646B2 - Power transmission mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission mechanism between an input shaft and an output shaft.

[0002]

2. Description of the Related Art
When power is transmitted from a power source to a load via a shaft, there is a problem that vibrations generated from the power source and the accompanying noise are directly transmitted to the load. An object of the present invention is to provide a power transmission mechanism that makes it difficult for vibration generated from a power source and noise accompanying the vibration to be transmitted to a load, and that can reliably transmit power to a load even when a load torque increases. It is the purpose.

[0003]

In order to achieve the above object, the invention according to claim 1 comprises a magnet provided on an input shaft, a magnet provided on an output shaft and facing the magnet,
A magnetic fluid interposed between the two magnets, and a stopper provided on at least one of the input shaft and the output shaft to engage the input shaft and the output shaft when the input shaft moves by a predetermined displacement, wherein the stopper is provided. The invention described in Item 2 is an electrode provided on the input shaft, an electrode provided on the output shaft and facing the electrode, an electrorheological fluid interposed between the two electrodes, and applying a voltage between the two electrodes. A power supply for applying an electric field to the electrorheological fluid, and a stopper provided on at least one of the input shaft and the output shaft, the stopper engaging the input shaft and the output shaft when the input shaft moves by a predetermined displacement, Claim 3
The described invention provides a magnet and an electrode provided on an input shaft, a magnet and an electrode provided on an output shaft and facing the magnet and the electrode, respectively, and a magnetorheological fluid interposed between the two electrodes and the two magnets. A power source for applying a voltage between the two electrodes to apply an electric field to the magnetic electrorheological fluid, and engaging the input shaft and the output shaft provided on at least one of the input shaft and the output shaft when the input shaft moves by a predetermined displacement. And a stopper for causing the stop.

[0004]

When power is applied from the power source to the input shaft, the power is applied to the input shaft.
According to the invention described in claim 2, in the invention described in claim 2, the attraction between the electrically polarizable particles due to the electric field between the electrodes is performed through the magnetic fluid whose viscosity is increased due to the attraction force between the magnetic particles due to the magnetic field of the magnet. According to the third aspect of the present invention, the viscosity is increased due to the attractive force between the magnetic and electro-polarizable particles due to the magnetic field between the magnets and the electric field between the electrodes via the electrorheological fluid whose viscosity is increased due to the force. Power is transmitted to the output shaft via the enhanced magnetic electrorheological fluid, and the vibration and the accompanying noise generated from the power source and transmitted to the input shaft are absorbed by the magnetic fluid, the electrorheological fluid or the magnetic electrorheological fluid. And is not transmitted to the output shaft.

When the load torque increases, the load torque becomes larger than the attractive force between the magnetic particles, the electropolarizable particles, or the magnetic electropolarizable particles of the magnetic fluid, the electrorheological fluid, or the magnetic electrorheological fluid. Although the relative position between the input shaft and the output shaft changes, the input shaft and the output shaft are engaged by the stopper at the time when the relative position changes to some extent, so that power is reliably transmitted to the output shaft even if the load torque is large.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show an embodiment of the present invention. In the figure, 1 is an input shaft and 2 is an output shaft (FIG. 2).
It is. The input shaft 1 has, for example, two N
The magnet 3 is disposed so that the poles and two south poles are alternately located along the peripheral surface, and stoppers 4 and 4 are provided at positions directly opposite to each other on the peripheral surface. The output shaft 2 also has, for example, 2
The magnet 5 is arranged so that the N poles and the two S poles are alternately located along the peripheral surface, and stoppers 6 and 6 are provided at positions directly opposite to each other on the peripheral surface. As shown in FIG. 2, the magnet 3 and the magnet 5 are opposed to each other.
The end portion of the output shaft 2 is provided on the inner peripheral surface of the cup-shaped portion 7, and the stoppers 6, 6 are provided on this inner peripheral surface. Input shaft 1
Although not shown, a flange is provided near the large diameter portion to form a case in cooperation with the cup-shaped portion 7. Although not shown, the case is configured to have a leakage prevention structure, and the inside is filled with a magnetic fluid 8.

When the input shaft 1 is rotated by a driving source in a state where the magnetic poles of the magnet 3 of the input shaft 1 and the magnet 5 of the output shaft 2 are in a positional relationship as shown in FIG. Since the viscosity is increased by the magnetic field generated by the magnets 3 and 5, when the load torque applied to the output shaft 2 is small, the output shaft 2 rotates following the input shaft 1 in the above positional relationship. When the load torque applied to the output shaft 2 increases and the load torque becomes larger than the attraction force between the magnetic particles of the magnetic fluid 8 due to the magnetic field, the interval between the magnetic particles increases, and the rotation of the output shaft 2 is delayed from the input shaft 1. As shown in FIG. 1B, the stoppers 6 and 6 of the output shaft 2 are
, The output shaft 2 rotates in synchronization with the input shaft 1.

When the output shaft 2 approaches the positional relationship as shown in FIG. 1B, the N and S poles of the magnet 3 of the input shaft 1 and the N and S poles of the magnet 5 of the output shaft 2 respectively. The repulsive force increases due to an increase in the opposing area of the stopper 6, and the repulsive force and the attractive force acting between the N pole of the magnet 3 of the input shaft 1 and the S pole of the magnet 5 of the output shaft 2 cause the stopper 6, Shock at the time of engagement between the stopper 6 and the stoppers 4, 4 is reduced.

When the load torque is reduced, the attraction between the N pole of the magnet 3 of the input shaft 1 and the S pole of the magnet 5 of the output shaft 2 causes the positional relationship between the magnetic poles of the magnets 3 and 5 shown in FIG. The output shaft 2 returns to the state shown in FIG. 1A even when the input shaft 1 stops.

In the embodiment shown in FIGS. 1 and 2, the magnet 3 of the input shaft 1 and the magnet 5 of the output shaft 2 each have four magnetic poles.
When the input shaft 1 and the output shaft 2 are stopped, the stopper 6 has a phase angle of 90 ° with respect to the stopper 4, but the number of magnetic poles of the magnets 3 and 5 is increased, and the phase of the stoppers 4 and 6 is increased. It is preferable to reduce the angle.

FIG. 3 shows an input shaft 1 for transmitting power in the axial direction.
And another embodiment of the present invention applied to the output shaft 2.
A cylindrical magnet 3 is disposed at the tip of the input shaft 1 so that N poles and S poles are alternately arranged in the axial direction, and the tip of the output shaft 2 is opposed to the magnet 3 via a gap. The cylindrical magnet 5 is disposed so that the north pole and the south pole alternate in the axial direction. The cylindrical magnet 5 and the large-diameter portion 9 of the output shaft 2 supporting the cylindrical magnet 5 A magnetic fluid 8 is placed in a case formed by a disc-shaped lid member 10 attached to the other end of the magnet 5.
Is filled. The penetrating part of the disc-shaped lid member 10 of the input shaft 1 is configured so that the magnetic fluid 8 does not leak.

In the state where no power is applied to the input shaft 1 in the direction of, for example, the output shaft 2, the state is as shown. When the power is applied to the input shaft 1 in the direction of the output shaft 2, the magnets 3 and 5 are used. Since the viscosity is increased by the magnetic field, the output shaft 2
When the load torque applied to the input shaft 1 is small, the output shaft 2 follows the input shaft 1 and moves in the same direction. When the load torque applied to the output shaft 2 increases, the input shaft 1 comes into contact with the stopper 11 of the output shaft 2, and thereafter, the output shaft 2 moves together with the input shaft 1. As the output shaft 2 approaches the stopper 11, the area of the S magnetic pole and the N magnetic pole of the magnet 3 facing the S magnetic pole and the N magnetic pole of the magnet 5 increases and the repulsive force increases. Shock at the time of engagement between the input shaft and the stopper 11 is reduced by the attraction force acting between the N and S magnetic poles of the magnet 3 and the S and N magnetic poles of the magnet 5 of the output shaft 2 respectively. When the load torque is reduced and when the power to the input shaft 1 is lost, the input shaft 1 and the output shaft 2 return to the illustrated state.

When power is applied to the input shaft 1 in a direction opposite to the previous direction, and the load torque applied to the output shaft 2 increases, the input shaft 1 hits the stopper 11a of the output shaft 2.

FIG. 4 shows an embodiment of the second aspect of the present invention. In the figure, a pair of electrodes 13, 13 and a pair of stoppers 14, 14 are provided on a peripheral surface of a large diameter portion 12 of the input shaft 1, and an inner peripheral surface of a bowl-shaped portion 15 of the output shaft 2 is provided. A pair of electrodes 16, 16 is provided, and an electrorheological fluid 18 is filled in a case formed by a flange portion 17 and a bowl-shaped portion 15 provided on the input shaft 1.

The electrorheological fluid 18 is a well-known one, and disperses, in an insulating oil, electro-polarizable particles in which a polymer core such as an acrylic polymer is provided with a surface layer of a substance having a large dielectric constant such as a tin oxide. A dispersed electrorheological fluid or a liquid crystal type electrorheological fluid.

The electrodes 13, 13 and 16, 16 are connected to one terminal and the other terminal of a power source (not shown), respectively.
An electric field is applied to 8. Electrorheological fluid 18 to which an electric field is applied
Since the viscosity of is increased, when the input shaft 1 is rotated by the power source, the output shaft 2 is rotated via the electrorheological fluid 18. While the load torque applied to the output shaft 2 is small, FIG.
The input shaft 1 and the output shaft 2 rotate in the state shown in FIG.
When the load torque applied to the output shaft 2 increases and becomes larger than the electrostatic absorption force acting between the electro-polarizable particles of the electrorheological fluid 18, the distance between the particles widens, and the rotation of the output shaft 2 rotates from the input shaft 1. The output shaft 2 is connected to the stopper 14 of the input shaft 1
The output shaft 2 rotates in synchronization with the input shaft 1 thereafter.

When the load torque decreases, the relative position shown in FIG. 4A is generated by electrostatic attraction acting between particles of the electrorheological fluid 18 interposed between the electrode 13 of the input shaft 1 and the electrode 16 of the output shaft 2. Then, the output shaft 2 returns. The same situation occurs when the input shaft 1 stops.

Also in this embodiment, the electrode 1 of the input shaft 1
It is preferable that the number of the electrodes 3 and the number of the electrodes 16 of the output shaft 2 be increased to reduce the distance between the stopper 14 and the electrodes 16 when the load torque is small.

The invention described in claim 2 can be applied to transmission of power by an input shaft and an output shaft that move in the axial direction as shown in FIG.

In FIG. 4, an electrorheological fluid 1
8 is replaced with an insulating oil having magnetic and electrically polarizable particles in which a polymer core such as an acrylic polymer is provided with a surface layer of a substance having magnetic properties and a large dielectric constant such as ferrite. A dispersion type magnetic electrorheological fluid dispersed therein is used, and iron-based alloy magnets are used for the electrodes 13 and 16, and the magnetic poles of the magnets are arranged as shown in FIG. May be added at the same time. The electric and magnetic fields can be generated by separate electrodes and magnets.

[0021]

According to the present invention, the vibrations generated from the power source and the accompanying noise are hardly transmitted from the power source to the load via the drive shaft. Further, there is an effect that power can be reliably transmitted to the load even when the load torque increases.

[Brief description of the drawings]

FIGS. 1 (A) and 1 (B) are operation explanatory diagrams of an embodiment according to the first aspect of the present invention; FIGS.

FIG. 2 is a partially omitted perspective view of the embodiment of the invention.

FIG. 3 is a sectional view of another embodiment of the above invention.

4A and 4B are a sectional view of the invention according to claim 2 and a sectional view taken along line BB in FIG. 4A.

[Explanation of symbols]

 1 Input shaft 2 Output shaft 3 Magnet 4 Stopper 5 Magnet 6 Stopper 8 Magnetic fluid 11, 11a Stopper 13 Electrode 14 Stopper 16 Electrode 18 Electro-rheological fluid

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-1730 (JP, A) JP-A-2-102928 (JP, A) Jikku Sho 29-15910 (JP, Y1) Jiko Sho 29- 15909 (JP, Y1) (58) Field surveyed (Int. Cl. ⁶ , DB name) F16D 35/00 F16D 7/02 F16D 37/02 H02K 49/10

Claims (3)

(57) [Claims] 1. A magnet provided on an input shaft, a magnet provided on an output shaft and facing the magnet, a magnetic fluid interposed between the two magnets, and provided on at least one of an input shaft and an output shaft. A power transmission mechanism comprising a stopper for engaging the input shaft and the output shaft when the input shaft moves by a predetermined displacement. 2. An electrode provided on an input shaft, an electrode provided on an output shaft and facing the electrode, an electrorheological fluid interposed between the two electrodes, and a voltage applied between the two electrodes. A power supply for applying an electric field to the electrorheological fluid; and a stopper provided on at least one of the input shaft and the output shaft for engaging the input shaft and the output shaft when the input shaft moves by a predetermined displacement. mechanism. 3. A magnet and an electrode provided on the input shaft, a magnet and an electrode provided on the output shaft and facing the magnet and the electrode, respectively, and a magnetorheological fluid interposed between the two electrodes and the two magnets. A power source for applying a voltage between the two electrodes to apply an electric field to the magnetic electrorheological fluid, and engaging the input shaft and the output shaft provided on at least one of the input shaft and the output shaft when the input shaft moves by a predetermined displacement. A power transmission mechanism comprising: