JP2007244014A - Noncontact gear by magnetism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mechanism for transmitting power under completely noncontact state in which the reduction ratio can be increased. <P>SOLUTION: In the noncontact gear where gears having teeth magnetized with the same polarity by a magnetic body or an electromagnet located in the vicinity thereof are arranged on the drive side and the driven side, a gap is provided between the teeth of drive side gear and the teeth of driven side gear, and rotational movement is transmitted by magnetic repulsion under noncontact state, the number of teeth is different between the driven side gear and the drive side gear. A means for putting the gear made of steel material between ring magnets can be employed for magnetizing the gear. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a non-contact gear in which a pair of gears transmits torque in a non-contact manner by magnetic force, and more specifically, a non-contact gear in which the number of teeth of the pair of gears is different and torque can be transmitted in an accelerating / decelerating manner. About.

In a gear pair that transmits torque, many gears require lubricating oil to prevent wear and the like. However, food processing machines, precision equipment, equipment operating in a vacuum state, and the like have been demanding non-lubricated gears that do not have to worry about scattering of lubricating oil.
Further, a normal gear transmits torque by contact of the tooth portion of the gear pair with or without lubricating oil. For this reason, there are problems such as a decrease in transmission efficiency due to frictional resistance, a decrease in life due to wear, and generation of contact noise. For this reason, attempts have been made to drive the gear pair in a non-contact manner, and in particular, many reports have been made that use magnetic force for the non-contact means.

JP 2002-218735 A JP 2005-233326 A JP 2005-253292 A

  As shown in FIG. 4 or 5, the gears described in Patent Documents 1 and 2 are configured such that magnets are alternately arranged on the outer periphery of the gears in N poles and S poles, and the gears are driven by magnetic attraction between the N poles and the S poles. It is. For this reason, there is a problem that the installation of the magnet is complicated and the manufacturing cost is high. Further, as shown in FIG. 6, the gear described in Patent Document 3 magnetizes the gear by sandwiching a gear made of a steel material having a high magnetic permeability with magnets from both sides. For this reason, there is an advantage that the magnet can be installed at a relatively low cost. Further, the present invention is characterized in that the gear pair is driven in a non-contact manner by using a magnetic repulsive force (so-called repulsive force) instead of using a magnetic attractive force. However, transmission of higher torque is desired.

  Therefore, an object of the present invention is to provide a gear to which a speed reduction mechanism that realizes transmission of high torque is added.

  In the invention according to claim 1, a gear having teeth magnetized with the same polarity by a magnetic body or an electromagnet arranged in the vicinity is arranged on the driving side and the driven side, and between the teeth of the driving side gear and the driven side teeth. In a non-contact gear having a clearance and transmitting a rotational motion in a non-contact manner by magnetic repulsion, the number of teeth of the driven gear and the drive gear is different.

  The invention according to claim 2 is the non-contact gear according to claim 1, wherein the number of teeth of the driven gear is larger than the number of teeth of the driving gear.

  The invention according to claim 3 is the non-contact gear according to claim 1, wherein the number of teeth of the driven side gear is smaller than the number of teeth of the driving side gear.

  The invention according to claim 4 is the non-contact gear according to any one of claims 1 to 3, wherein the driven-side and / or driving-side gears are sandwiched between magnetic bodies or electromagnets.

  The invention according to claim 5 is the non-contact gear according to any one of claims 1 to 4, wherein a side view shape of a tooth end of the driven side and / or driving side gear is an arc shape.

  The invention according to claim 6 is the non-contact gear according to any one of claims 1 to 5, wherein the shape of the side view of the tooth bottom between the teeth on the driven side and / or the drive side is an arc shape. .

  The invention according to claim 7 is the non-contact gear according to any one of claims 1 to 6, wherein a plurality of non-contact gears are installed in the direction of the rotation axis of the gear.

  The invention according to claim 8 is a planetary gear mechanism characterized in that the non-contact gear according to any one of claims 1 to 7 is included in its configuration.

  According to the present invention, in a non-contact gear using magnetic repulsion, the number of teeth on the driving side and the driven side can be made different, so that the reduction ratio can be increased, and the number of teeth on the driving side and the driven side is the same. In comparison, the transmission torque can be increased. Further, the present invention has an advantage that can be suitably applied to a planetary gear mechanism including a sun gear, a planetary gear, and an internal gear.

  Embodiments of the present invention will be described below with reference to the drawings. Note that the present invention is not limited thereby.

FIG. 1 shows dimensions and shapes of the designed sun gear and planetary gear. The sun gear 1 has 9 teeth and the planetary gear 2 has 13 teeth. The sun gear 1, the planetary gear 2, and the internal gear (not shown) were each magnetized to the north pole by a ring magnet, but there was a problem that magnetic attraction was generated between the tooth tips. The cause of the magnetic attractive force despite the same polarity is considered to be one of the causes of the difference in the tooth surface magnetic flux density of the gear pair that applies the magnetic repulsive force.
In other words, in the case of gears having different numbers of large and small teeth, the outer diameter of the ring magnet to be attached becomes larger with the large gear than with the small gear, so it is considered that the magnetic pole of the large gear tooth tip has changed to the S pole. Therefore, if the magnetic flux density generated from the gear teeth of the small and large gears is equal, the magnetic repulsion spur gear pair having a reduction gear ratio does not change the magnetic poles and generates a magnetic repulsion between the gears, thereby enabling non-contact torque transmission. FIG. 2 shows the attachment state of the gear and the ring magnet. A gear made of steel 3 is sandwiched between ring magnets. At this time, the ring magnet was arranged such that the N pole side 4n was on the steel material 3 side and the S pole side 4s was on the outside.

  In addition, three-dimensional static magnetic field analysis of the sun gear and the planetary gear was performed. Table 1 shows the analysis conditions. The tooth tip magnetic flux density when the outer diameter of the ring magnet was increased every 0.5 mm was calculated. The analysis was performed by dividing a three-dimensional solid model created by Solid works into tetrahedral elements and using COMOS EMS. Moreover, the air model created the model which covers the whole model shown in FIG. The air model was 60 mm × 60 mm × 40 mm on the sun gear side, and 80 mm × 80 mm × 40 mm on the planetary gear side. The number of elements was 80570 to 334365 and the number of nodes was 14191 to 57520 although it was different depending on the analysis model. The element reference size was set to 1 mm for the sun gear, 2 mm for the ring magnet for the sun gear and the air model, and 4 mm for the ring magnet for the planetary gear and the air model due to the limitation of the memory of the computer.

  FIG. 3 shows the analysis results. The vertical axis represents the product of the magnetic flux density B generated from the tooth tip of the analytical model with the ring magnet attached to the gear and the correction value (L / (D−d)). L is the total thickness of the gear and the magnet, D is the diameter of the tooth tip circle of the gear, and d is the inner diameter of the gear. The horizontal axis is the distance X between the tooth tip and the ring magnet shown in FIG. The solid line in FIG. 3 is a straight line represented by the least square approximation (lnBL / (D−d) = − 4.78lnX + 16.51), and the correlation coefficient with the analysis value group is 0.91. From this least square approximation, the magnetic flux density B is expressed as a function of the tooth tip-to-magnet distance X, and it can be said that the tooth tip magnetic flux density B decreases as the tooth tip-to-magnet distance X increases. If this least square approximation is used, the outer diameter of the ring magnet for equalizing the tooth surface magnetic flux density can be obtained. For example, in the case of Example 1, if a ring magnet having an outer diameter ratio corresponding to the gear ratio is used and sandwiched between both sides of the large and small gears, the meshing tooth tip magnetic flux density can be made equivalent.

  In the non-contact gear of the above embodiment, the number of teeth of the driven side and the driving side gear is different, so that the rotational speed can be made different between the driven side and the driving side gear.

The present invention includes various embodiments in addition to the above examples.
Non-contact gears with more gears on the driven side than the gears on the drive side have fewer teeth on the drive side than the gears on the drive side. Rotation can be decelerated.

  Non-contact gears with less gear teeth on the driven side than the gears on the drive side have more teeth on the drive side than the gears on the driven side. Can rotate a lot.

  In the non-contact gear in which the driven side and / or the driving side gear is sandwiched between magnetic bodies or electromagnets, magnetic bodies or electromagnets are installed on both sides of the gear as means for magnetizing the gears. For example, a cylindrical ring magnet having a hole in the center can be installed on both sides of the gear. At this time, the rotation shaft of the gear can be passed through the hole of the ring magnet.

  The non-contact gear in which the side view shape of the tooth end of the driven side and / or the drive side gear has an arc shape is obtained by making the side view shape of the tooth end (so-called tooth tip portion) of the gear into an arc shape, Compared to rectangular tooth profiles and involute tooth profiles with sharp vertices, the magnetic flux is made uniform. For this reason, the magnetic repulsive force between gears can be made to act suitably, and a transmission force can be improved.

  A non-contact gear in which the side view of the root between the teeth on the driven side and / or the drive side has an arc shape has an acute angle with the side view of the root between the teeth having an arc shape. By eliminating the apex, the influence of interference between adjacent magnetic fluxes is reduced. For this reason, the magnetic repulsive force between gears can be made to act suitably, and a transmission force can be improved.

  A plurality of non-contact gears installed in the direction of the rotation axis of the gear can increase the transmission torque by installing a plurality of gears on the same axis of the gear.

Moreover, this invention is a planetary gear mechanism characterized by including the non-contact gear in any one of said above in a structure.
The planetary gear mechanism of the present invention is a power transmission mechanism using the present non-contact gear for any or all of the planetary gear, the sun gear, and the internal gear constituting the planetary gear mechanism, which causes a problem in the conventional planetary gear mechanism. Since there is no excessive meshing between the planetary gear and the internal gear, vibration and noise can be prevented, and torque can be transmitted quietly and with high efficiency.

It is the dimension shape of the gearwheel which shows an Example. It is a figure which shows the attachment state of the ring magnet in the gearwheel which shows an Example. It is a graph which shows the result of having performed magnetic field analysis about the gear of an example. It is a figure which shows the example of the conventional non-contact gear. It is a figure which shows the example of the conventional non-contact gear. It is a figure which shows the example of the conventional non-contact gear.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Sun gear, 2 ... Planetary gear, 3 ... Steel material, 4s ... Ring magnet (S pole side)
4n Ring magnet (N pole side)

Claims (8)

  A gear having teeth magnetized to the same polarity by a magnetic body or an electromagnet arranged in the vicinity is arranged on the driving side and the driven side, and a gap is provided between the teeth of the driving side gear and the driven side, so that the non-magnetic A non-contact gear that transmits rotational motion by contact, wherein the number of teeth of a driven gear and a drive gear is different.   The non-contact gear according to claim 1, wherein the number of teeth of the driven gear is larger than the number of teeth of the driving gear.   The non-contact gear according to claim 1, wherein the number of teeth of the driven gear is smaller than the number of teeth of the driving gear.   The non-contact gear according to any one of claims 1 to 3, wherein the driven-side and / or driving-side gears are sandwiched between magnetic bodies or electromagnets.   The non-contact gear according to any one of claims 1 to 4, wherein a side view shape of a tooth end of the driven side and / or the driving side gear is an arc shape.   The non-contact gear according to any one of claims 1 to 5, wherein a side view shape of a tooth bottom between teeth on the driven side and / or the driving side is an arc shape.   The non-contact gear according to any one of claims 1 to 6, wherein a plurality of non-contact gears are installed in a rotation axis direction of the gear. A planetary gear mechanism comprising the non-contact gear according to any one of claims 1 to 7 in its configuration.

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