JPS5886858A - Decelerating mechanism by stepping-motor - Google Patents

Abstract

PURPOSE:To remove the backlash of a gear in case of standstill by disposing two pinions separately connected to the two stepping-motors severally installed to one gear or rack at predetermined mounting angles. CONSTITUTION:The decelerating mechanism is formed in such a manner that the pinions 3, 4 are each mounted to the output shafts of the two stepping- motors 5, 6, which are electrically connected in parallel, are turned in the same direction and have the same specification, and the pinions 3, 4 are engaged with separate positions of one gear 1(or rack). Here, the two stepping-motors 5, 6 are installed so that the mounting angles in the direction of rotation to the center lines of the pinions 3, 4 are mutually displaced in the opposite direction from a magnetically balanced point, and torque generated at positions where several stepping-motor 5, 6 is mutually displaced at the prescribed angles in the opposite direction from the magnetically balanced point is balanced when standstill.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a speed reduction mechanism that uses a stepping motor as a prime mover.

SUMMARY OF THE INVENTION An object of the present invention is to provide a speed reduction mechanism that has a simple configuration and is capable of eliminating gear backlash when stationary.

Generally, a rolling motion reduction mechanism consisting of a combination of a pinion and a gear, or a linear reduction mechanism consisting of a combination of a pinion and a rack are basic mechanical elements. However, these mechanical elements have problems due to backlash when used for purposes that require bidirectional drive and high positioning accuracy, and various countermeasures have been devised heretofore.

The present invention is capable of eliminating backlash during quiet operation and enabling high-precision positioning in such a speed reduction mechanism that uses a stepping motor as a prime mover.

The speed reduction mechanism according to the present invention will be explained below with reference to the drawings. With the speed reduction mechanism of this invention, two stepping motors with the same specifications are electrically connected in parallel and rotate in the same direction.
Two binions are attached to each output shaft of the motor, and different locations of one gear or rack are driven by the two binions. FIG. 1 shows an embodiment of the reduction mechanism according to the present invention when a binion and a gear are combined.
In Figure 5, gear +1111. Binion (3) and
The stepping motors (5) and (6) (a 4-phase motor is shown in Fig. 1) that drive the shafts 1, 1, and binions (3) and (4), respectively, are connected to the drive excitation circuit ()). All terminals are electrically connected in parallel.

Although not shown here, the same effect can be achieved even if all the corresponding windings of two stepping motors are connected in series and connected to the drive excitation circuit1.Of course, even with this configuration, all the positional phases If the relationships are set exactly the same, two binions will act exactly the same as one binion, and backlash will exist.

However, as shown in FIG. 2, the stepping motor has a static torque even when it is stationary, and generates a static torque that attempts to deviate the magnetic equilibrium point and restore it to zero. In stepping motors that use all permanent magnets, such as hybrid PM motors, even in the non-excited state, the permanent magnet generates what is called detent torque.
It has some static torque. Also.

All stepping motors can generate such static torque 7 by continuing to energize the windings of one or more phases even when the stepping motor is at rest.

Therefore, when assembling the device of this invention, one stepping motor (5) is maintained at a fully magnetic equilibrium point, and after its binion (3) gear (11%) is assembled in the correct rank, the other one is assembled. The stepping motor (61 and its pinion (4) are assembled by intentionally deviating 2δ from the magnetic equilibrium point with respect to the gear (+) or rack described above to generate a restoring force due to static torque. In this way. If you do that.

When the frictional force in this system is small, as a result, the static torques of the respective stepping motors (5) and +61 are balanced and balanced at positions deviated by δ in opposite directions from the magnetic equilibrium point. do. At this time.

If the gear (1) or the rack described above is pressed or pulled by a force corresponding to the static torque T8, the puncture crash can be eliminated.

During operation, two stepping motors (51
, (61 are driven together in the same direction, so during acceleration, deceleration, and constant load operation, the two binions (31
, 141 come into contact with gear (1) or rack teeth in the same rotational direction, resulting in a dynamic crash.
Backlash does not occur during no-load constant speed operation, just as when the motor is stationary.

that's all,! ! Therefore, it is possible to obtain a deceleration mechanism without crash by using the device of the present invention.

This has the effect of ensuring high positional accuracy even when driving in both directions.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the invention in which a pinion and a gear are combined, and FIG. 2 is a graph diagram showing the relationship between static torque and magnetic position of a stepping motor. (1)...gear, (2)...gear output shaft, 13
) L41...-binion, +51 +61... stepping motor, (7)... drive excitation circuit. Shin Kuzuno - Figure 1 Figure 2

Claims (1)

[Claims] (l) Two binions are arranged on one gear or rack, and the two stepping motors are electrically connected to operate in parallel so that they rotate in the same direction. , the two stepping motors are separately mechanically connected to the two binions, and the mounting angle of the two stepping motors in the rotational direction with respect to the center line of the binions is at a magnetic equilibrium point. In a stepping motor, the two stepping motors are mounted so as to have deviations in opposite directions from each other, and the two stepping motors generate static torque in opposite directions when stationary to eliminate backlash. Yoru reduction mechanism. (2) A permanent magnet type stepping motor is used as the stepping motor, and the detent torque generated by the permanent magnet generates a restoring static torque when it is deviated from the magnetic equilibrium point. A speed reduction mechanism using a stepping motor according to claim 1.