JPH0647760U - Reducer - Google Patents

Abstract

(57) [Summary] [Purpose] (1) To provide a reduction gear having an extremely large reduction gear ratio. (2) To provide a small and inexpensive speed reducer (power booster). (3) To provide a speed reducer suitable for fine adjustment of measuring instruments and the like. [Structure] A speed reducer configured to generate a rotational force due to a difference in peripheral length between an inner surface of a cylinder and an outer surface of the cylinder which are partially in contact with each other by a frictional force.

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] [Industrial field of application] One of the objects of the present invention is that a reduction ratio suitable for manipulator operation using a microscope or feedback control using a magnet scale is extremely large. It is to provide a speed reducer having no backlash.

Still another object is to provide a small and inexpensive speed reducer (power booster) for controlling a ball valve or the like with an electric motor.

Still another object is to provide an extremely small and backlash-free speed reducer suitable for fine adjustment of measuring instruments and the like.

 [0002] [Prior Art] (1), a reduction gear device (harmonic drive) using an elliptical elastic gear.

(2), worm wheel speed reducer.

(3), a speed reducer using a planetary gear.

(4), Reduction gear with external spur gear.

(5) A general friction transmission device.

 [0003] [Problems to be solved by the invention] (1) To provide a reduction gear having an extremely large reduction ratio and no backlash.

(2) To provide a compact and inexpensive speed reducer (power booster).

(3) An extremely small and backlash-free speed reducer is provided.

 [Means for Solving the Problems] The outer ring of the rolling bearing is a thin-walled cylindrical member (3), and the outer circumference of the shaft is not a perfect circle to keep the rolling bearing radially deformed (compressed and expanded). A state in which the shaft is directly connected to the input shaft (1) and the cylindrical member (4) having an inner peripheral length slightly longer than the outer peripheral length of the thin cylindrical member (3) is elastically deformed in the radial direction. And is arranged outside the thin-walled cylindrical member (3).

 [Operation] When the input shaft (1) is rotated, the inner ring (8) of the rolling bearing directly connected to the input shaft (1) rotates. At this time, when the thin-walled cylindrical member (3) is fixed, the cylindrical member (4) rotates normally, and when the cylindrical member (4) is fixed, the thin-walled cylindrical member (3) reverses. The reduction ratio is a value obtained by dividing the difference between the inner peripheral length of the cylindrical member (4) and the outer peripheral length of the thin-walled cylindrical member (3) by the peripheral length of the fixed cylindrical member.

Details will be described in the example section.

 [0006] [Embodiment] A description will be given below with reference to the drawings.

1 is an axial sectional view of the present invention, which is connected to an output shaft (2) through a thin portion so as to transmit a rotational force while elastically deforming a cylindrical member (4) in a radial direction. A thin-walled cylindrical member (3) corresponding to the outer ring of the rolling bearing is attached to the fixed housing (5) so as to be radially deformable.

A shaft (9) having a non-circular cross section is driven into the inner ring (8) of the rolling bearing so as to keep the radially deformed state. This shaft is directly connected to the input shaft (1).

Between the thin cylindrical member (3) and the inner ring (8), balls (10) of a ball bearing and the like are supported and attached to a retainer (not shown).

According to the dimensional relationship of the structure in the present invention, the elastic deformation state of the cylindrical member (4) is maintained in the radial direction, and the repulsive force of this elastic deformation causes the inner peripheral surface of the cylindrical member (4) and the thin-walled cylindrical member ( The outer peripheral surface of 3) is partially brought into pressure contact.

Next, the driving operation will be described.

When the input shaft (1) rotates, the inner ring (8) of the rolling bearing rotates, and with this rotation, the radial deformation of the thin-walled cylindrical member (3) fixed to the housing rotates (sequential deformation). . The elastic deformation of the cylindrical member (4) also rotates according to the deformation of the thin-walled cylindrical member (3). At this time, the outer peripheral surface of the thin-walled cylindrical member (3) and the inner peripheral surface of the cylindrical member (4) are pressed against each other by the repulsive force of the elastic deformation of the cylindrical member (4), and static friction is generated between them. . This static friction force does not cause slippage between the two, and the difference between the outer circumference of the thin-walled cylindrical member (3) and the inner circumference of the cylindrical member (4) must be absorbed by the rotation of the cylindrical member (4). Instead, the cylindrical member (4) will rotate.

For example, assuming that the outer diameter of the thin-walled cylindrical member (3) and the inner diameter of the cylindrical member (4) are 100 mm and 100 + 0.01 mm, respectively, in a perfect circle, the cylindrical member (4) (output shaft) is 1 / 10,000 per rotation of the input shaft. It will rotate.

Next, the factors that select each component when implementing the present invention will be described.

It is necessary that the thin-walled cylindrical member (3) has low resistance to radial deformation and does not deform (dent) against pressure contact with balls of the rolling bearing. Therefore, a thin cylinder made by pressing a stainless steel plate or the like is suitable. For the cylindrical member (4), a material with a large elasticity and a high elastic limit, that is, a steel material that can be heat-treated (quenched) is suitable because it requires a repulsive force when elastically deformed in the radial direction. . Also, as a matter of course, both cylindrical members are required to have strength to withstand the transmission force of the output shaft.

Next, the energy loss in the speed reducer of the present invention will be described. Most of the energy loss occurs as the temperature rises due to repeated radial elastic deformation of the cylindrical member (4), which is similar to the energy loss due to the vibration of the leaf spring. Therefore, in order to improve the transmission efficiency, it is necessary to increase the elastic modulus of the cylindrical member (4), that is, increase the rigidity, that is, increase the wall thickness. In this case, stable transmission force is required. In order to obtain high precision, it is necessary to improve the processing accuracy of parts. However, there is a case where stable control, miniaturization, and low price are required even if the transmission efficiency is sacrificed, which is not the only factor in the world where transmission efficiency is required. In such a case, the present invention exerts a great effect.

 [Advantage of Invention] In the present invention, the reduction ratio becomes larger as the difference between the inner peripheral distance of the cylinder of the cylindrical member (4) and the outer peripheral distance of the cylinder of the thin-walled cylindrical member (3) becomes smaller. Therefore, the difference in the circumferential distance can be reduced to the extent that the machining accuracy of the cylindrical surface is allowable, and thus the reduction gear ratio can be increased. For example, when the difference between the circumferential distances is 0.03 mm and the circumferential distance of the cylinder is 300 mm, the reduction ratio is 1/10000.

This corresponds to 100 times that of the conventional speed reducer.

Next, in the conventional general gear transmission and friction transmission, the ratio of the large wheel to the small wheel, which is the reduction ratio, inevitably results in a large wheel diameter when trying to obtain a large reduction ratio. It becomes so large that miniaturization is impossible. On the other hand, in the case of the present invention, the difference in the circumferential distance between the inner surface of the cylinder and the outer surface of the cylinder which are in contact with each other is the main factor that determines the reduction gear ratio, and it is possible to reduce the size regardless of the reduction gear ratio.

Next, in the present invention, the holding force of the output shaft against the fluctuation of the external force applied to the output shaft is generated by the frictional force between the adjacent cylindrical surfaces, which is the same as the maximum allowable transmission force of the reduction gear. . Therefore, in the present invention, there is no backlash, and even if the input shaft is opened, the output shaft is held with the maximum allowable transmission force. This is an important factor that enables stable control when controlling extremely small displacements.

Next, in the present invention, since the contact pressure between the contacting cylindrical surfaces for generating the transmission force is obtained by elastically deforming the cylindrical member (4), precise processing accuracy is required. It is possible to obtain a stable transmission force without using. This is also a factor that the present invention exerts a great effect in terms of downsizing and cost reduction.

Next, the fine adjustment mechanism of the measuring instrument will be described. The thin cylindrical member (3) is fixed to the housing by frictional force such as fluororesin, and when the thin cylindrical member (3) itself is rotated, 1: 1 rotation is transmitted to the cylindrical member (4) and the input shaft is rotated. When (1) is rotated, the thin-walled cylindrical member (3) is fixed to the housing by the frictional force of the fluororesin, and extremely decelerated rotation is transmitted to the cylindrical member (4). Therefore, conventional rapid feed and fine adjustment can be performed with the same mechanism.

[Brief description of drawings]

FIG. 1 is an axial sectional view of the present invention. FIG. 2 is a sectional view of the present invention perpendicular to the axis. [Explanation of Codes] (1) is an input shaft. (2) is the output shaft. (3) is a thin-walled cylindrical member. (4) is a cylindrical member. (5) is a housing. (6) is a bearing. (7) is a bearing. (8) is the inner ring of the rolling bearing.
(9) is an axis whose cross section is not a perfect circle. (10) is a ball bearing ball (steel ball).

Claims (1)

[Scope of utility model registration request] The outer ring of the rolling bearing is a thin-walled cylindrical member. To keep the rolling bearing radially deformed (compressed and expanded), a shaft with an outer circumference different from the true circle is driven and this shaft is directly connected to the input shaft. A cylindrical member having an inner peripheral length slightly longer than the outer peripheral length of the outer ring (thin-walled cylindrical member) is elastically deformed in the radial direction, and is arranged outside the outer ring (thin-walled cylindrical member) of the rolling bearing. Speed reducer.