JPH06213297A - Magnet type ball planetary reduction gear - Google Patents

Abstract

PURPOSE:To provide a magnet type ball planetary reduction gear of which the maintenance and management of friction force of steel balls are easy and the construction is simple. CONSTITUTION:A drive disc 4 made of iron is fixedly secured to a drive shaft 2, and an annular rolling contact surface of steel balls is provided on the outer circumference. A first and a second magnets 5,6 are fixedly secured on both sides of the drive disc 4, and a steel ball 7 train is annularly arranged on the outer circumference of the drive disc 4. A fixed disc 8 which is movable in the axial direction and impossible to relatively rotate, is provided on one side of the drive disc 4, and this is provided with an annular rolling contact surface 8a of the steel ball 7. A driven disc 12 made of iron which is movable in the axial direction and impossible to relatively rotate, is fitted to a driven shaft 3, and this is provided with an annular rolling contact surface 12a of the steel ball 7. The contact position of the fixed disc 8 against the steel ball 7 and the contact position of the driven disc 12 against the steel ball 7 are shifted from each other in the radial direction, and hence the driven shaft 3 is rotated at reduced speed against the drive shaft 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ball planetary speed reducer utilizing the frictional force between a steel ball and an iron disk due to a magnetic force.

[0002]

2. Description of the Related Art Gear type planetary speed reducers that have been used for a long time have many problems in terms of performance in addition to the necessity of refueling and the generation of noise, and various improvements have been studied so far. There is. As one of them, a method utilizing friction of a roller has been proposed, but it has not been put into practical use due to problems such as a pressure contact structure of the roller and abrasion.

[0003]

Therefore, according to the present invention, the frictional force of the steel ball can be easily maintained and controlled, and the structure is simple.
An object of the present invention is to provide a magnetic ball planetary speed reducer that can be downsized.

[0004]

In the present invention, in order to solve the above-mentioned problems, a drive disk 4 made of iron is fixed to the drive shaft 2, and an annular steel ball rolling surface is provided on the outer periphery of the drive disk 4. Also provided, the first and second annular magnets 5 and 6 located on both sides of the drive disk 4 are fixed to each other with their poles facing each other in the axial direction, and can be rolled around the outer circumference of the drive disk 4. 7 rows of steel balls are annularly arranged on one side of the drive disk 4 in the axial direction, and a fixed disk 8 is provided so as to be movable in the axial direction and non-rotatable relative to each other. Is provided with an annular rolling surface 8a rotatably contacting with the driven disk 3 and is located on the other side in the axial direction of the drive disk 4 and is made of an iron material which is movable in the axial direction and cannot rotate relative to the driven shaft 3. The driven disk 12 is attached, and the driven disk 12 is provided with an annular steel ball rolling surface 12a that is in rolling contact with the steel ball 7. Constituted the magnet ball planetary reduction gear and a contact position of the steel ball 7 of the contact position and the driven disc 12 against the steel balls 7 of the stationary disc 8 is shifted in the radial direction.

Further, by mounting a movable ring 9 on the outer periphery of the fixed disk 8 so that the relative position can be changed in the axial direction, and by making an annular edge 9b of the movable ring 9 rollably contact the steel ball 7, The magnetic ball planetary speed reducer is configured so that the reduction ratio can be changed.

[0006]

In the magnetic ball planetary speed reducer of the present invention, when the drive shaft 1 rotates, the steel balls 7 contacting the drive disk 4 are moved.
Is the rolling surfaces 8a, 12a of the fixed disk 8 and the driven disk 12.
It rolls up and revolves in the same direction as the drive shaft 2. Rolling surface 8
Since the contact positions of a and 12a on the steel ball 7 are different from each other in the radial direction, the driven shaft 3 decelerates and rotates with respect to the drive shaft 2. The reduction ratio is changed by moving the movable ring 9 relative to the fixed disk 8 in the axial direction and bringing its annular edge 9b into contact with the steel ball 7.

[0007]

Embodiments of the present invention will be described with reference to the drawings.
1 is a vertical sectional front view of a speed reducer according to the present invention, and FIG.
II-II sectional view in FIG. 3, and FIG. 3 is a longitudinal sectional front view of a part of the reduction gear transmission according to the present invention.

1 and 2, a drive shaft 2 and a driven shaft 3 are rotatably supported on opposite sides of the case 1 so as to face each other. A drive disc 4 made of iron is fixed to the drive shaft 2 in the case 1, and the first and second annular magnets 5 and 6 are located on both sides of the drive disc 4 in the axial direction.
Are fixed with the same poles facing each other in the axial direction.

The steel balls 7 are annularly arranged in a row on the outer periphery of the drive disk 4 so as to be rollable. The drive disk 4 has grooves 4b formed between annular ribs 4a, 4a facing each other on both sides in the axial direction. The steel ball 7 falls into the groove 4b and is restricted from moving in the axial direction. Annular rib 4
The peripheral edges of a and 4a provide rolling surfaces for the steel balls 7.

The fixed disk 8 is provided in the case 1 so as to be movable in the axial direction so as not to rotate relatively. An annular edge of the fixed disk 8 is in rolling contact with the steel ball 7 and constitutes a rolling surface 8a. A movable ring 9 is screwed onto the outer circumference of the fixed disk 8 so as to be movable back and forth in the axial direction. One end side of the movable ring 9 in the axial direction can be rotatably contacted with the steel ball 7, and teeth 9a are formed on the inner circumference of the other end side. An adjustment shaft 20 is rotatably pierced through the lid 1a on one end side of the case 1, and a gear 11 fixed to the tip of the adjustment shaft 20 meshes with teeth 9a on the inner circumference of the movable ring 9. Therefore, by rotating the adjustment shaft 20, the movable ring 9
Can be rotated relative to the drive disk 8 to move the movable ring 9 forward and backward on the drive disk 8 in the axial direction. Thus, a closed magnetic circuit of the magnet 5-fixed disc 8-steel ball 7-driving disc 4-magnet 5 is formed, and the fixed disc 8 and the movable ring 9 are attracted to the steel ball 7.

The driven disk 12 is mounted in the case 1 so as not to rotate relative to the driven shaft 3 but movable in the axial direction. The annular edge of the driven disk 12 contacts the steel ball 7 to form the rolling surface 12a. This contact point is located radially outside the contact point of the fixed disk 8 with the steel ball 7. Then, the magnet 6-the driven disk 12-the steel ball 7
-Drive disk 4-A closed magnetic circuit of the magnet 6 is formed and the driven disk 12 is attracted to the steel ball 7.

In the illustrated embodiment, magnets 13 and 14 are fitted in the groove 4b of the drive disk 8 to reinforce the attraction force of the steel ball 7 to the drive disk 8.

In the speed reducer configured as described above, the rotation of the drive shaft 2 is transmitted to the drive disk 4, and the steel ball 7 contacting the outer periphery of the drive disk 4 contacts the fixed disk 8 and rotates around the axis. Revolve around. The steel ball 7 rotates the driven disk 12, and this rotation is taken out from the driven shaft 3. Then,
The reduction ratio η1 of the reduction gear transmission in the state where the edge of the fixed disk 8 is in contact with the steel ball 7 is obtained as follows with reference to FIG. In the figure, P0 is a contact point between the drive disk 4 and the steel ball 7, P1 is a contact point between the fixed disk 8 and the steel ball 7, and P2.
Is a contact point between the driven disk 12 and the steel ball 7.

[Equation 1] Further, the speed reduction ratio η2 of this speed reducer in a state where the edge of the movable ring 9 is in contact with the steel ball 7 is obtained as follows with reference to FIG. In the figure, P1 'is a contact point between the movable ring 9 and the steel ball 7.

[Equation 2]

Further, this embodiment has the following features. (1) Since steel balls for bearings that are extremely hard, highly accurate, and inexpensive can be used as steel balls, a structure having a simple structure and high performance can be manufactured. (2) It does not require refueling and has low noise. (3) When the load exceeds the design allowable transmission force, slippage occurs between the disk and the steel ball, so there is no risk of failure due to overload. (4) Since the rotation transmitting force of the steel ball is secured only by the strong magnetic force of the small magnet, it is easy to reduce the size and weight.

[0015]

As described above, in the present invention, the iron drive disc 4 is fixed to the drive shaft 2, the annular disc rolling surface is provided on the outer periphery of the drive disc 4, and the drive disc 4 is provided. The first and second annular magnets 5 and 6 located on both sides of the drive disk 4 are fixed to each other with their poles facing each other in the axial direction, and seven rows of steel balls are rotatably mounted on the outer circumference of the drive disk 4. It is arranged in an annular shape, and a fixed disk 8 is provided on one side of the drive disk 4 in the axial direction so as to be movable in the axial direction and non-rotatable relative to the fixed disk 8.
An annular rolling surface 8a that rotatably contacts the steel ball 7 is provided, and it is located on the other side of the drive disk 4 in the axial direction.
A driven disk 12 made of iron is attached to the driven disk 12 such that the driven disk 12 is movable in the axial direction and cannot rotate relative to the steel ball 7.
An annular steel ball rolling surface 12a is provided so as to be freely rollable, and the contact position of the fixed disk 8 with respect to the steel ball 7 and the contact position of the driven disk 12 with respect to the steel ball 7 are displaced in the radial direction to decelerate the magnetic ball planet. Since the device is configured, there is no need to refuel,
It is possible to provide a ball planetary speed reducer that can easily maintain and manage the frictional force of a steel ball, has a simple structure, and can be downsized.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view of a speed reducer according to the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is an explanatory diagram of a speed reducer according to the present invention.

[Explanation of symbols]

 2 drive shaft 3 driven shaft 4 drive disk 5 first magnet 6 second magnet 7 steel ball 8 fixed disk 8a rolling surface 9 movable ring 12 driven disk 12a rolling surface

Claims (2)

[Claims] 1. A drive shaft and a driven shaft which are arranged so as to be rotatable relative to each other on a common shaft center, an iron drive disc which is fixed to the drive shaft, and is provided with an annular steel ball rolling surface on the outer periphery, First and second annular magnets, which are located on both sides of the drive disc in the axial direction and have the same poles facing each other in the axial direction, and are fixed to the drive shaft, and are annularly arranged on the outer periphery of the drive disc so as to be rollable. A plurality of steel balls, and an annular rolling surface provided on one side in the axial direction of the drive disk so as to be movable in the axial direction and non-rotatable relative to each other, and in rolling contact with the steel balls. A fixed disk and an annular rolling surface located on the other side in the axial direction of the drive disk and rollingly contacting the steel ball, the driven disk being movable in the axial direction and not relatively rotatable. A driven disk made of iron attached to the shaft, and a contact position of the fixed disk with a steel ball, A magnetic ball planetary speed reducer characterized in that a position of contact of the driven disk with the steel ball is displaced in the radial direction. 2. A movable ring is attached to the outer circumference of the fixed disk so that the relative position can be changed in the axial direction, and the reduction ratio is set by bringing the annular edge of the movable ring into rolling contact with the steel ball. The magnet type ball planetary speed reducer according to claim 1, wherein the magnet type ball planetary speed reducer is configured to be changeable.