JPH0366959A - Speed reducer - Google Patents

Abstract

PURPOSE:To enhance the speed reducing efficiency and prevent the generation of backlash as in the case of gear transmission by adopting a planetary roller system which is a speed reducing mechanism performed only by rolling friction transmission combined with a differential mechanism. CONSTITUTION:An input shaft, that is, a center roller 5, is rotated by the driving of a motor provided outside, so that a driven roller 6 in contact with the center roller rolls, as well as a supporting member, by which the rotary pivot of the driven roller is fixed, is integrally rotated in the same direction concentrically with the center roller. In other words, the input rotating speed is largely reduced by a planetary roller mechanism that the driven roller is rotated around the center roller while being rotated on its axis, and transmitted onto the output shaft side. A flange member 13 is contact with the driven roller is rotated in the same direction following the rotation of the driven roller, and an output shaft formed coaxially with the flange member is rotated. In this case, the assembling of a pressure ring 18, the driven roller and the flange member forms a differential mechanism by double rolling friction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a planetary roller speed reducer suitable for use in an electric pan head for rotating a photographic camera mounted on a tripod, for example.

[Conventional technology]

An electric camera head automatically performs panning (horizontal rotation) and tilting (up and down movement) of a photographing camera by operating a drive motor, and allows the camera to be remotely controlled for wild bird observation. It is used to do things like.

In such an electric pan head, the rotational speed of the drive motor is drastically reduced via a reduction gear so that an appropriate rotational speed of the photographing camera can be obtained. Traditionally, such reducers have been used that combine a large number of gears to obtain the deceleration speed, but with this gear transmission type reducer, there is backlash between the combined gears, which makes it difficult to photograph. There are problems such as screen shake or large vibrations when the camera starts rotating.Furthermore, there are problems such as large deceleration loss and the need for large equipment including the motor to obtain the necessary reduction ratio. Ta.

On the other hand, a planetary roller speed reducer has also been proposed for use in general equipment, which allows a large speed reduction ratio to be obtained even in the negative stage. In this known planetary roller speed reducer 24 shown in FIG. 5, a center roller 26 as a sun roller is formed at the output end of an input rotating shaft 25, and three rollers are arranged equally in contact with the concentric roller 26. A driven roller 27 as a top-shaped planetary roller is disposed, and the driven roller 27 is rotatably supported by a rotation support shaft 28 via a needle bearing 29, and the rotation support shaft 28 is an output rotation shaft. It is fixed to an output board 31 formed coaxially with 30. Therefore, the driven roller 27 revolves around the center roller 26 while rotating due to the rotation of the manual rotation shaft 25, and transmits the decelerated rotation to the output rotation shaft 30. Furthermore, these mechanisms are housed as one body within the housing 32.

In addition, in this reducer 24, in order to make sufficient contact between the center roller 26 and each driven roller 27, an outer circumferential ring 33 having a box-shaped cross section is provided between the inner wall of the housing 32 and the outer peripheral end of the driven roller 27. Place around this outer puffer fish 33
When the fixing ring 34 and the pressurizing ring 35 are arranged in such a way that they are sandwiched, and the housing 1I36 is applied, as shown in FIG. It is pushed in the X direction, and the bottom part is pushed out in the Y direction to press the driven roller 27 toward the center of the center roller 26.

[Problem to be solved by the invention]

However, in this prior art, the input rotating shaft 2
The three driven rollers 27 that contact the center roller 26 coaxial with the output rotation shaft 30 are each rotatably supported by a concentric rotation support shaft 28. It has a structure fixed to an integrated output board 31. Therefore, the positioning accuracy of the rotation support shaft 28 is 3.
It is necessary to strictly control the dimensional accuracy of the diameter of the pitch circle that passes through the axis of the book rotation support shaft 28. If this dimensional accuracy is poor, poor contact will occur between the center roller 26 and each driven roller 27. There is a problem that abnormal wear of the center roller 26 or the driven roller 27 due to pressurized contact or lack of contact causes vibration or rattling on the driven roller 27 side, resulting in poor uniform rotation and even inability to rotate. There was a problem that the rotation accuracy was poor. Furthermore,
This speed reducer 24 is a mechanism that extracts the output from the output board 31 using only a combination of a center roller 26 and a driven roller 27. There was a demand for a transmission system that could transmit rotation to the engine, generate less vibration, and have a higher reduction ratio.

In view of these circumstances, the purpose of the present invention is to provide high deceleration efficiency, no backlash, smooth start and stop of rotation, less vibration, and improved positional accuracy of the rotation axis of each driven roller. To provide a planetary roller type speed reducer in which each driven roller is forcefully and evenly brought into contact with a center roller, and the rotational accuracy of the entire speed reducer can be maintained for a long period of time without particularly strictly regulating the speed.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a center roller formed coaxially with an input rotating shaft, a driven roller that contacts the center roller and revolves while rotating, and a driven roller that contacts the driven roller from the input side in the axial direction. a pressure ring having a tapered surface on the inner periphery; and an annular protrusion provided on the periphery of the flange with a tapered surface that is formed coaxially with the output rotating shaft and contacts the driven roller from the output side in the axial direction opposite to the pressure ring. and a pressurizing means for pressurizing the pressurizing ring in the axial direction from the input side, the rotary support shaft of the driven roller being rotatably eccentric. The present invention proposes a speed reducer characterized in that it is structured by a central shaft fitted with a bush, or by a freely rotatable eccentric shaft.

[Effect]

The input rotation shaft and the center roller are rotated by the drive of an externally attached motor, the driven roller that is in contact with the center roller is transferred, and the support member that fixes the rotation support shaft of the driven roller is integrally rotated. Rotates concentrically and in the same direction as the center roller. That is, the driven roller greatly decelerates the input rotation speed and transmits it to the output rotation shaft side by a planetary roller mechanism in which the driven roller revolves around the center roller while rotating. Furthermore, the flange member that is in contact with the rotating driven roller rotates in the same direction as the driven roller rotates, and the output rotating shaft formed coaxially with the flange member rotates. In other words, the difference in taper between the tapered surface on the inner periphery of the pressure ring and the tapered surface on the inner periphery of the annular protrusion on the periphery of the flange member appears as a difference in the contact area between the pressure ring of the driven roller and the flange member, and therefore the rotational speed The combination of the pressure ring, driven roller, and flange member forms a differential mechanism based on double rolling friction.

In addition, the pressure means using a spring body or the like biases the pressure ring toward the flange member, and brings each driven roller into contact with the pressure ring and the opposing tapered surfaces of the inner periphery of the flange member to urge it toward the center roller. to strengthen

Furthermore, even if there is a possibility that the contact between the driven rollers and the center roller may be uneven due to poor positioning accuracy of the rotation support shaft supported by the support member, that is, poor precision of the pitch circle, the rotation of each driven roller The support shaft is composed of six shafts fitted with eccentric bushings so as to be rotatable, so that the rotary support shaft automatically rotates under the pressure of the above-mentioned pressure means, and each driven roller and the center roller are evenly spaced. Correct the eccentric position so that they make contact with a suitable contact pressure. Note that the same objective can be achieved even if the rotational support shaft is not fitted with an eccentric bush, but instead is constructed of a freely rotatable eccentric shaft.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a side sectional view of the first embodiment of the reduction gear of the present invention, FIG. 2 is a sectional view taken along the line ff-ff in FIG.
Figures C) and (0) are partial cross-sectional views illustrating how to correct the malposition of the rotation support shaft in the reducer shown in Figure 1.

The speed reducer 1 of the present invention is housed integrally in a housing 2.

An input rotating shaft 3 connected to a drive motor (not shown) has a central roller 5 coaxially provided with a groove 4 around the periphery. Three spherical driven rollers 6 are arranged on the outer periphery of the center roller 5 so as to be in equal contact with the groove 4, and the rotational support shafts 7 forming the six axes of the driven rollers 6 are rotatably mounted. The eccentric bush 8 is fitted, and the needle bearing 9 is fitted around the bush 8 so that the driven roller 6 can freely rotate. In addition, eccentric bushing 8 and needle bearing 9
Place a retaining ring I on the end so that it does not come out.
O is alms. Both ends of the rotary support shaft 7 are fixed to support members 11, and the support members 11 are rotatable about the center roller 5 together with the driven roller 6. Further, on the output side of the support member 11 of the driven roller 6, a flange member 13 having an output rotating shaft 12 on its back is arranged.

This flange member 13 has an annular protrusion 1 on the input side of the periphery.
3a, and the inner circumferential surface of the annular protrusion 13a is
A tapered surface 14 that can make point contact with the outer surface of the driven roller 6
It's Toshide. In addition, the flange member 13 has a concentric output rotating shaft 12 extending to the output side on the back as described above with the pin 1.
5, and this output rotating shaft 12 is pivotally supported by the housing 2 with a ball bearing 16. The flange member 13 is in contact with the driven roller 6 and is rotatable with a thrust bearing 17 interposed in relation to the housing 2 on the back side. A pressure ring 18 is arranged on the input side of the driven roller 6;
8 has a tapered surface 19 on the inner circumference of the ring, and is slidably fitted into the inner wall of the housing 2, so that the tapered surface 19 makes point contact with the outer surface of the three driven rollers 6, respectively. Further, a ring-shaped spring body 20 is disposed on the input side of the pressure ring 18, and a housing cover 21 is attached to cover the spring body 20, thereby using the spring body 20 as a means for pressurizing the pressure ring 18. It can be used as a. In addition, the manual rotation shaft 3 is connected to the housing lid 2.
1 through a ball bearing 22.

In the embodiment shown above, the pressure ring 18 is biased toward the output side in the axial direction by the spring body 20 within the housing 2, and its tapered surface 19 makes point contact with each of the three driven rollers 6. 6 further makes point contact with the tapered surface 14 of the opposing flange member 13, so that each driven roller 6 is pressed toward the center roller by a vertical component force at the contact point, and also pushes the flange member 13 by a horizontal component force. Pressure is applied in the axial direction. Therefore, when the manual rotating shaft 3 is rotated by a motor (not shown), the center roller 5 formed coaxially rotates, and the three driven rollers 6 that are in contact with the groove 4 of the center roller 5 roll. Due to friction,
Each rotates around the rotation support shaft 7 in a direction opposite to that of the center roller 5, and also revolves concentrically and in the same direction as the center roller 5.

As a result, the flange member 13 in contact with the driven roller 6 also rotates in the opposite direction due to rolling friction and transmits the rotation to the output rotating shaft 12.

In this case, as mentioned above, the three driven rollers 6 are pressed against the center roller 5, but the support member 11 only supports the rotation support shaft 7 of the driven rollers 6 and is not directly connected to other members. are not restrained, and the positions are adjusted so that the three driven rollers 6 are in equal contact with the center roller 5 to maintain balance.

However, in preparation for the case where the pitch accuracy of the rotation support shaft 7 of the driven roller 6 cannot be achieved sufficiently due to component manufacturing, resulting in excessive contact or insufficient contact between the driven roller 6 and the center roller 5, in the present invention, the above-mentioned Characteristically, the driven roller 6
An eccentric bush 8 and a needle bearing 9 are rotatably fitted onto the outer periphery of the rotation support shaft 7. That is, as seen in FIGS. 2 and 3 <4>, (El), each of the three eccentric bushes 8 is configured to have an eccentric amount 8a. Therefore, as shown in FIG.
Even if a gap 8b is created between the center roller 5 and some of the driven rollers 6 due to a deviation from the center roller 5, as long as the gap 8b is within twice the eccentricity 8a of the eccentric bushing 8, the eccentric bushing 8 Automatic correction based on angular displacement can reduce the gap. In other words, the eccentric bush 8 having an eccentric amount 8a is rotatably inserted into the rotation support shaft 7, and
As mentioned above, the driven roller 6 is always urged in the direction of the center roller 5 by the pressure ring 18 and the flange member 13, and the balance between the three driven rollers 6 is maintained by the support member 11. In the process of rotation and revolution of the driven roller 6, as shown in FIG. It becomes like this.

Also, contrary to what is shown in FIGS. 3(A) and 3(II), -
Similarly, if the distance between the driven roller 6 and the center roller 5 is negative, and the two are strongly pressurized against each other, resulting in poor rotation or abnormal wear of the contact area, the eccentric bushing 8 should be Automatic correction by angular displacement is performed.

Furthermore, in the reducer of the present invention, the rotational input from the input rotating shaft is caused by rolling and friction transmission due to the point contact of the driven roller with the pressure member, and the extraction of rotational output from the driven roller is achieved by point contact with the flange member. Since this is done by rolling friction transmission, the reduction ratio can be increased, including the differential mechanism, and since only rolling friction transmission is used to transmit rotation from the input rotating shaft to the output rotating shaft, the reduction efficiency can be improved. transmission is improved, transmission becomes smoother, and vibration is reduced.

FIG. 4 is a sectional view of a main part of a second embodiment of the present invention, in which a rotation support shaft 7' of a driven roller 6' is formed as an eccentric shaft, and a needle bearing 9' is provided on the outer periphery of the driven roller 6'. This is different from the first embodiment in that the rotary support shaft 7', which is an eccentric shaft, is supported at both ends by the support member 11' via ball bearings 23.

In the case of this second embodiment as well, there is an effect of automatically correcting the position of the driven roller, as in the case of the rotary support shaft of the first embodiment using the eccentric bushing.

In addition, in the above reduction gear, if the motor is attached to the output rotation shaft side and rotation is input to the output rotation shaft, accelerated rotation will be obtained on the input rotation shaft, and the reduction gear of the present invention It can also be used as a machine.

The speed reducer of the present invention can be used not only as a speed reducer for an electric pan head, but also as a speed reducer or speed increaser for equipment that requires low rotational unevenness, low vibration, or low noise.

[Effects of the invention] As is clear from the above explanation, according to the invention, the deceleration mechanism uses only rolling friction transmission and uses a planetary roller system that also incorporates a differential mechanism, so the deceleration efficiency is high. , there is no backlash like in the case of gear transmission, and a reduction gear that can smoothly start and stop rotation is obtained, and the rotation support shaft of each driven roller is a 6-shaft or eccentric shaft fitted with an eccentric bushing. Because of this structure, even if there is a slight deviation in the positional accuracy of the rotation support shaft, the contact pressure of each driven roller with respect to the center roller is automatically corrected to be equal, and the rotational accuracy of the entire reducer is maintained. Moreover, due to this effect, it is no longer necessary to strictly regulate the positional accuracy of the rotation axis of each driven roller as before, and the production efficiency is improved.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of the first embodiment of the reduction gear of the present invention, and the second embodiment of the reduction gear of the present invention.
The figure is a cross-sectional view taken along the line ■-■ in Figure 1, and Figure 3 (<) (
a) is a partial sectional view illustrating how to correct the malposition of the rotary support shaft in the reducer shown in FIG. 1; FIG. 4 is a sectional view of main parts in the second embodiment of the reducer of the present invention; FIG. 6 is a side sectional view of a conventional reduction gear, and FIG. 6 is a partial sectional view illustrating the action of the outer peripheral ring in the reduction gear in FIG. 5. 1...Reducer 2...Housing 3...
・Input rotation axis 5...Center roller 6.6'...
- Followed rollers 7, 7'...Rotation support shaft 8...Eccentric bushing 9.9'...Needle bearing 11.11'...Support member 12...Output rotation shaft 13...Flange member 1
3a...Annular protrusion 14...Tapered surface 18...
・Pressure ring 19...Tapered surface 20...Spring body 21...Housing lid Figure 2 Figure 3 (A) (B) 7. Contents of amendment (1) Page 5, No. 18 of the specification Correct the line "unreasonably" to "reasonably." (2) "For the rotation support shaft 7" on page 12, line 16 of the specification.
is corrected to "the rotation support shaft 7". (3) "[Effects of the invention]" on page 15, line 7 of the specification is corrected to "[Effects of the invention]." (4) "The present invention" on page 15, line 8 of the specification is corrected to "the present invention." (5) "Hirokazu Kitazawa" on page 17, line 2 of the specification is corrected to "Swaraknos Ltd." Procedural amendment (voluntary) 1゜2゜3゜4゜Indication of the case 1999 patent application No. 202159 Name of the invention Reduction device Relationship to the case Patent applicant address 2545 Shiga, Suwa City, Nagano Prefecture name
Swaraknos Co., Ltd.

Claims (2)

[Claims] (1) It has a center roller formed coaxially with the input rotating shaft, a driven roller that contacts the center roller and revolves while rotating, and a tapered surface that contacts the driven roller from the axial input side on the inner periphery. a pressure ring, and a receiving plate formed coaxially with the output rotating shaft and having a tapered surface on the periphery of the flange that contacts the driven roller from the output side in the axial direction opposite to the pressure ring, on the inner periphery of an annular protrusion. A reduction gear comprising a flange member having a shape, and a pressurizing means for pressurizing the pressurizing ring in the axial direction from the input side, the rotary support shaft of the driven roller being a center shaft in which an eccentric bush is fitted rotatably. A speed reducer characterized by comprising: (2) Claim (2) characterized in that the rotation support shaft of the driven roller is constituted by a freely rotatable eccentric shaft (
1) The speed reducer described.