JPH11303950A - Transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To constitute a small-sized transmission having high efficiency by coaxially providing two planetary gears to be provided in the transmission and making the diameters of respective planetary gears different from each other. SOLUTION: The transmission having a planetary gear mechanism between an input shaft and an output shaft which are coaxially arranged is provided with first planetary gears 3a, 4a and 5a to be rotated and revolved around the outer periphery of a sun gear provided on one shaft, and second planetary gears 3b, 4b and 5b to be revolted while being rotated in an internal gear provided on the other shaft. The first planetary gears and the second planetary gears are coaxially connected to one another, and the pitch circle diameters of the first planetary gears and the second planetary gears are different from one another.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission using a planetary gear mechanism suitable for reducing or increasing speed, and more particularly, two planetary gears provided in a transmission are provided coaxially. The present invention relates to a transmission that can be reduced in size by making the diameters of the respective planetary gears different.

[0002]

2. Description of the Related Art Conventionally, a transmission using a planetary gear mechanism is well known. Referring to the drawings, a typical transmission will be described. FIG. 4 is a schematic front view and side view of the transmission. In the figure, reference numeral 51 denotes an input shaft. An external gear (sun gear) 52 is fixed to the input shaft 51. The external gear 52 has three planetary gears 53, 54, 55 having the same diameter and the same number of teeth. Are engaged. The three planetary gears 53, 54, 55 mesh with a fixed internal gear 56 that is in contact with their outer circumferences, respectively.
Are formed on the fixed body 57.

[0003] Rotating shafts 58, 59, 60 are fixed to the center of the three planetary gears 53, 54, 55, and the respective rotating shafts 58, 59, 60 are trifurcated at equal intervals. The carrier 61 is rotatably supported at the distal end thereof. The carrier 61 is provided with a bearing serving as an output shaft 62 at the center thereof, and the input shaft 51 described above is rotatably supported on the bearing. Have been. In this transmission, when the input shaft 51 rotates, the external gear 52 rotates, and the three planetary gears 53, 54, and 55 meshing with the external gear 52 rotate inside the fixed internal gear 56 while rotating. The carrier 61 is also rotated by the rotation of the three planetary gears 53, 54, 55, and the rotation of the carrier 61 is taken out from the output shaft 2.

[0004]

In the above transmission, the rotational speed of the input shaft is N1, the rotational speed of the output shaft 62 is N2, the pitch diameter of the external gear 52 is D1, and the pitch of the planetary gears 53, 54, 55 is Assuming that the circle diameter is D2, the relationship between the number of revolutions and the pitch circle diameter is as follows. N2 / N1 = D1 / 2 (D1 + D2) Therefore, in the above-described transmission, the pitch diameter of the planetary gears 53, 54, and 55 is set to D2 to increase the reduction ratio.
Therefore, there is a problem that the transmission itself becomes large. Also, when trying to reduce the size of the transmission, the number of teeth is reduced and the pitch of the reduction ratio is large, so that an intermediate setting cannot be made. Further, when gears having slightly different numbers of teeth are engaged with the same planetary gear to reduce the speed, there is a problem that efficiency may be deteriorated.

Therefore, the present invention provides a planetary gear comprising the above-mentioned transmission, which is constituted by two gears: a first planetary gear meshing with a fixed gear and a second planetary gear meshing with an internal gear provided on an output shaft. The pitch circle diameter of the first planetary gear meshing with the fixed gear is made larger, the pitch circle diameter of the second planetary gear meshing with the internal gear is made slightly smaller, and the tooth shapes of the two gears are all standard. Accordingly, it is an object of the present invention to configure a transmission having a large speed ratio and capable of being reduced in size, and to solve the above problems.

[0006]

For this reason, the technical solution adopted by the present invention is a transmission having a planetary gear mechanism between an input shaft and an output shaft arranged coaxially, wherein the planetary gear mechanism is A first planetary gear that rotates and revolves around the outer periphery of a sun gear provided on one of the shafts, and a second planetary gear that revolves while revolving within internal teeth provided on the other shaft, wherein the first planetary gear is provided. The transmission is characterized in that the gear and the second planetary gear are coaxially coupled, and the pitch diameters of the first and second planetary gears are different from each other.

In a transmission having a planetary roller mechanism between an input shaft and an output shaft arranged coaxially, the planetary roller mechanism rotates and revolves around the outer periphery of a sun roller provided on one of the shafts. A planetary roller, and a second planetary roller which revolves while rotating inside an inner roller provided on the other shaft,
The transmission is characterized in that the first planetary roller and the second planetary roller are coaxially connected, and the diameters of the first planetary roller and the second planetary roller are slightly changed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a front view and a side sectional view of a transmission according to a first embodiment.

In FIG. 1, reference numeral 1 denotes an input shaft, and an external gear (sun gear) 2 is fixed to the input shaft 1. The external gear 2 has three first planetary gears having the same diameter and the same number of teeth. 3a, 4a,
5a are engaged. Three first planetary gears 3a, 4
The fixed gear 6a is formed on the fixed body 6 with the fixed internal gear 6a in contact with the outer circumference thereof. Also, three first planetary gears 3a, 4a, 5
Rotating shafts 8, 9, and 10 are fixed to the center of a, and the respective rotating shafts 8, 9, and 10 are rotatably supported by a ring-shaped carrier 11 (rotating shafts 8, 9 and 9). , 1
The axis of 0 is on a circle of diameter D).

The first planetary gears 3a, 4a, and 5a are integrally provided with second planetary gears 3b, 4b, and 5b coaxially, and the three second planetary gears 3b, 4b, and 5b are the first planetary gears. The gears 3a, 4a, and 5a have a pitch circle diameter α · d slightly smaller than the pitch circle diameter d. Also, the three second planetary gears 3b, 4b, 5b have a rotating shaft 2 at the center thereof.
1, 22, 23 are fixed, and the respective rotating shafts 21,
The shafts 22 and 23 are rotatably supported by a ring-shaped carrier 24.

[0011] The three second planetary gears 3b, 4b, 5b
It meshes with an internal gear 29a formed on the output shaft 29 and also meshes with a backup gear 25. The backup gear 25 is supported by a bearing 26 on a shaft 27 integral with the external gear 2. The shaft 27 is rotatably supported by a bearing 28 provided on an output shaft 29. In this transmission, when the input shaft 1 rotates, the external gear 2 rotates, and the three first planetary gears 3 a, 4
a and 5a revolve in the fixed internal gear 6 while being united by the carrier 11 while rotating. By the revolution of the three first planetary gears 3a, 4a, 5a, the first planetary gears 3a,
The second planetary gears 3b, 4b, 5b integral with 4a, 5a also revolve while rotating inside the internal gear of the output shaft 29 by the carrier 24 while rotating, and the output shaft 29 rotates with the speed reduced in accordance with this. Then, the rotation of the output shaft 29 is taken out as an output.

The operation of the transmission will now be described. The transmission comprises two gears, a first planetary gear meshing with a fixed gear and a second planetary gear meshing with an internal gear provided on an output shaft. The pitch circle diameter of the first planetary gear meshing with the fixed gear is set to a large diameter d, and the pitch circle diameter of the second planetary gear meshing with the internal gear is set to a slightly smaller diameter α · d,
Further, since all the tooth profiles of the two gears are formed as standard, the circumference of the first planetary gear 3a meshing with the fixed gear is rotated once, and the second planetary gear 3b coaxial with the circumference L1.
2 is reduced as shown in FIG. 2, and the output shaft is decelerated by the difference L3.

The reduction theory will be further described. The rotation shafts 8, 9, 10 of the first planetary gear and the rotation shaft 2 of the second planetary gear 2
D is the diameter of the carrier that supports the axes of 1, 22, and 23, and three first planetary gears 3a that mesh with the fixed gear 6a.
The pitch circle diameter of 4a, 5a is d (= m · zm is a module, z is the number of teeth), and the pitch circle diameter of the second planetary gears 3b, 4b, 5b meshing with the internal gear 29a provided on the output shaft is α · d
When d> α · d, the reduction ratio γ is the pitch circle diameter of the external gear 2 of the input shaft 1: d1 = D−d (1) The pitch circle diameter of the internal gear 29 a of the output shaft 29: d2 = D + α · d (2) The pitch circle diameter of the fixed gear 6a of the fixed body 6: d6 = D + d (3) Assuming that the rotation speed of the planetary gear is N, the rotation speed of the carrier 11: Nc = N · d / (D + d) ( 4) Number of rotations of input shaft 1: N1 = N · d / (D−d) + Nc (5) Number of rotations of output shaft 29: N2 = Nc−N · α · d / (D + α · d) (6) ( Solving from 1) to (6) with γ = N2 / N1 gives γ = (D−d) · (1−α) / [2 · (D + α · d)]. Therefore, in the above-described transmission, if the pitch circle diameter of the planetary gear meshing with the fixed gear is set to the large diameter d, and the pitch circle diameter of the gear meshing with the internal gear is set to a slightly smaller diameter α · d, if the transmission is small, A large reduction ratio can be obtained.

Next, a second embodiment of the present invention will be described with reference to FIG. The second embodiment is characterized in that a planetary roller (friction wheel) is used instead of the planetary gear used in the first embodiment. In the figure, 31
Is an input shaft. An outer roller (sun roller) 32 is fixed to the input shaft 31. A plurality of (eight in this example) first planetary rollers 33a having the same diameter mesh with the outer roller 32. ing. The first planetary rollers 33a are frictionally joined to fixed inner rollers 36a that are in contact with their outer circumferences, respectively. The fixed inner rollers 36a are formed on the fixed body 36. The center of the first planetary roller 33a is on a circle having a diameter D).

The first planetary roller 33a is coaxially provided with a second planetary roller 33b having a diameter α · d slightly smaller than the diameter d of the first planetary roller 33a. The second planetary roller 33b is frictionally connected to the inner roller 34 formed on the output shaft 40 and frictionally connected to the backup roller 35.
The shaft is supported by a shaft 38 integral with the outer roller 32. The shaft 38 is rotatably supported by a bearing 39 provided on an output shaft 40. In this transmission, when the input shaft 31 rotates, the outer roller 32 rotates, and the first planetary roller 33a frictionally joined to the outer roller 32 revolves within the fixed inner roller 36a while rotating. First planetary roller 33a
, The second planetary roller 33b also rotates by friction within the inner roller 34 of the output shaft 40 while rotating, and the output shaft 40 rotates in a decelerated state with the rotation.
Is taken as output.

The speed reduction theory of the speed reducer according to the second embodiment is as follows.
The description is omitted because it is similar to that of the first embodiment.
Therefore, in the transmission according to the second embodiment, the diameter of the first planetary roller frictionally joined to the fixed inner roller 36a is set to the large diameter d, and the diameter of the second planetary roller frictionally joined to the output shaft 40 to the inner roller 34. Is slightly smaller than α · d, a large reduction ratio can be obtained if the size is small. In the first and second embodiments, by setting the input shaft as the output shaft and the output shaft as the input shaft, the transmission can be a gearbox.

[0017]

As described in detail above, according to the present invention,
The planetary gear (planet roller) provided in the transmission is
By providing the planetary gears (planet rollers) with different diameters, it is possible to achieve an excellent effect that an efficient and small transmission can be configured.

[Brief description of the drawings]

FIG. 1 is a front view and a side sectional view of a transmission according to a first embodiment of the present invention.

FIG. 2 is an operation explanatory view of a planetary gear of the transmission according to the first embodiment of the present invention.

FIG. 3 is a front view and a side sectional view of a transmission according to a second embodiment of the present invention.

FIG. 4 is a front view and a side sectional view of a conventional transmission.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Input shaft 2 External gear 3a-5a 1st planetary gear 3b-5b 2nd planetary gear 6 Fixed body 6a Fixed gear 8-10 Rotating shaft 11 Carrier 21-23 Rotating shaft 24 Carrier 25 Backup gear 26, 28 Bearing 27 Shaft 29 Output shaft 31 Input shaft 32 Outer roller 33a First planetary roller 33b Second planetary roller 36 Fixed body 36a Fixed inner roller 37 Bearing 40 Output shaft

Claims (2)

[Claims] 1. A transmission having a planetary gear mechanism between an input shaft and an output shaft disposed coaxially, wherein the planetary gear mechanism rotates around the outer periphery of a sun gear provided on one of the shafts.
A first planetary gear 3a, 4a, 5a that revolves, and a second planetary gear 3b that revolves while rotating inside an internal tooth provided on the other shaft,
4b and 5b, wherein the first planetary gear and the second planetary gear are coaxially coupled, and the first planetary gear and the second planetary gear have different pitch circle diameters from each other. Transmission. 2. A transmission having a planetary roller mechanism between an input shaft and an output shaft arranged coaxially, wherein the planetary roller mechanism rotates and revolves around the outer periphery of a sun roller 32 provided on one of the shafts. And a second planetary roller 33b that revolves while rotating inside an inner roller 34 provided on the other shaft. The first planetary roller and the second planetary roller are coaxially coupled. A transmission wherein the roller diameters of the first planetary roller and the second planetary roller are slightly changed.