Reduction gear having a self-locking function without a ring gear and self-locking method of the reduction gear

Abstract

The present invention relates to a reduction gear with a self-locking function without a ring gear and a self-locking method for the reduction gear, and in particular, to a first, second and third planetary gears supported at different positions on one side of a carrier, which is the input side, and configured to be able to rotate and revolve, and arranged in n sets, and when either the first sun gear or the second sun gear is fixed and the other sun gear is changed to the input side and rotated, the self-locking function does not increase the speed, and the speed increase ratio becomes 0 (Zero) (a stopped state in which the sun gear used as the input side itself cannot rotate), realizing self-locking in which operation is impossible.

Description

Technical Field

[0001] The present invention relates to a speed reducer having a self-locking function without a ring gear and a self-locking method for the speed reducer. In particular, the first, second, and third planetary gears are supported at different positions on one side of the carrier on the input side and are configured to be rotatable and revolvable, and are arranged in n sets. When either one of the first sun gear or the second sun gear is fixed and the other sun gear is changed to the input side and rotated, it is not speeded up by the self-locking function, and the speed ratio becomes 0 (zero) (the sun gear itself used as the input side cannot rotate and is in a stopped state), and the operation becomes impossible. The present invention relates to a speed reducer having a self-locking function without a ring gear and a self-locking method for the speed reducer.

Background Art

[0002] Generally, driving sources such as engines and motors rotate at high speeds for efficiency reasons. Depending on the device, the rotational speed is reduced at a certain ratio to receive power supply at an appropriate RPM and be used. At this time, the speed reducers generally used combine a large number of gears to achieve speed reduction by the difference in the number of teeth. A planetary gear device is applied as such a speed reducer. The planetary gear speed reducer has a sun gear installed on the central axis, and a plurality of planetary gears that mesh with the sun gear and revolve and rotate around it are arranged. The planetary gears are supported by a carrier and rotate. It is composed of a ring gear that meshes with the outside of the planetary gears.

[0003] Also, in the structure of the speed reducer, in order to achieve a large speed reduction, the connection between the gears must be performed in three or more stages. Therefore, the volume and weight increase due to many gears of large and small diameters and a large number of shafts. Since a larger reduction can be achieved at a lower stage as the diameter difference is larger, it is preferable to increase the diameter difference between the gears.

[0004] However, since a ring gear is provided in a normal planetary gear reduction device, there are problems not only in manufacturing difficulty but also in increased manufacturing cost. In addition, when high-ratio reduction, low-ratio reduction, or speed increase is required, it has to be configured in multiple stages, resulting in problems of increased manufacturing cost and volume.

[0005] Moreover, since there is no self-locking function, in situations where reverse prevention is necessary or when a heavy object has to be lifted and stopped, another braking device has to be used for control, which makes the usage state inconvenient and results in poor controllability.

[0006] On the other hand, when arranging planetary gears around the sun gear, there are difficulties in reducing the number of planetary gears as a constraint related to the number of teeth to reduce manufacturing cost or increasing the number of planetary gears to increase strength.

[0007] An example of such technology is disclosed in Patent Documents 1 to 3 below.

[0008] For example, Patent Document 1 below discloses a reduction device including a housing in which an internal gear is formed and a planetary gear and a sun gear are sequentially engaged in the axial direction thereof, a drive shaft penetrating the housing and coupled to the sun gear, and an output shaft arranged in parallel with the internal gear and coupled to a drive gear having a different number of teeth from the internal gear that meshes with the planetary gear together. Even when a load is applied to the drive shaft, the tooth grooves of the internal gear and the drive gear mesh with the teeth of the planetary gear together, and the drive gear is self-locked by the internal gear fixed to the housing.

[0009] In addition, Patent Document 2 below discloses a speed reducer including a sun gear installed on the rotation shaft of a motor, a plurality of planetary gears arranged around the sun gear so as to mesh with the sun gear, a carrier that is connected to the shafts of the planetary gears and rotates, a fixed internal gear fixed at a certain interval outside the planetary gears, and a rotating internal gear that meshes with and rotates outside the planetary gears and the carrier, and a moving means provided on the fixed internal gear and moving the rotating internal gear forward and backward in the longitudinal direction of the rotation shaft according to the supply and cutoff of power.

[0010] On the other hand, Patent Document 3 below discloses a power transmission device for a hybrid vehicle that can distribute engine output to drive wheels by using a Ravigneaux gear train in which a single pinion planetary gear is integrally formed with a double pinion planetary gear including a carrier in which two pinion gears are combined, or two or more clutches, so as to improve fuel efficiency by realizing two or more types of engine-fixed gear stages.

[0011] In the technology disclosed in Patent Document 1 as described above, when high-ratio deceleration, low-ratio deceleration, or speed increase is required, it has to be configured in multiple stages, and there is a problem that the number of teeth of the gears is restricted.

[0012] In addition, in the technology disclosed in Patent Document 2, by amplifying and transmitting the rotational force of the motor, the responsiveness during braking can be improved, but there is a problem that the number of teeth of the gears is restricted as in Patent Document 1.

[0013] On the other hand, in the technology disclosed in Patent Document 3, although a Ravigneaux gear train in which a single pinion planetary gear and a double pinion planetary gear are integrated and two or more clutches are used, there is a problem that high-ratio deceleration cannot be performed.

[0014] That is, the simple planetary gear, double planetary gear, and Ravigneaux planetary gear systems used in the conventional technologies as described above cannot achieve a high reduction ratio, and the maximum reduction ratio obtained in a single stage is about 1 / 11. When a high reduction ratio is required, there is a problem that a two-stage or more coupling method must be used. In addition, there are manufacturing restrictions that the number of teeth of the ring gear and the planetary gears must be specified as a multiple of the number of sets of planetary gears and arranged accordingly.

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0015] The above-described present invention can realize various gear speed ratios from high reduction ratios to low reduction ratios in a reduction device. The reduction device has no ring gear element and consists only of external gears, eliminating the difficulty of manufacturing, reducing space, and bringing about a manufacturing cost reduction effect. On the other hand, due to the ease of processing, it is suitable for mass production. In addition, the self-locking function can prevent reverse rotation, so it is easy to control and can be used in various ways. An object of the present invention is to provide a reduction device having a self-locking function without a ring gear and a self-locking method of the reduction device.

MEANS FOR SOLVING THE PROBLEMS

[0016] To achieve the above object, a reduction device according to an aspect of the present invention includes a carrier that rotates as an input side, a first sun gear provided concentrically with the carrier, a first planetary gear meshing with the first sun gear, a second planetary gear meshing with the first planetary gear, a third planetary gear meshing with the second planetary gear, and a second sun gear that is concentric with the carrier, provided in parallel with the first sun gear, and meshing with the third planetary gear, the difference between the number of teeth of the first sun gear and the number of teeth of the second sun gear is at least one, and the first, second, and third planetary gears are supported at different positions on one side of the carrier so as to be rotatable and revolvable, and are arranged in n sets, The carrier is on the input side, the first sun gear is on the fixed side, the second sun gear is on the output side. Define Z1 as the number of teeth of the first sun gear and Z2 as the number of teeth of the second sun gear. If Z1 < Z2 and (Z2 - Z1) < Z1, the output of the second sun gear will be a deceleration in the same direction. If Z1 > Z2 and (Z1 - Z2) < Z2, the output of the second sun gear will be a deceleration in the opposite direction. If the second sun gear is changed to the input side and rotated while satisfying only one of the conditions for the deceleration to be executed, it will not be speeded up by the self-locking function, and the speed-up ratio will be 0 (zero) (the sun gear itself used as the input side is in a stopped state where it cannot rotate). This is the characteristic.

[0017] The speed reduction device according to another aspect of the present invention includes a carrier that rotates as an input side, a first sun gear provided concentrically with the carrier, a first planetary gear meshing with the first sun gear, a second planetary gear meshing with the first planetary gear, a third planetary gear meshing with the second planetary gear, and a second sun gear that is concentric with the carrier, provided in parallel with the first sun gear, and meshing with the third planetary gear. The difference between the number of teeth of the first sun gear and the number of teeth of the second sun gear is at least one. The first, second, and third planetary gears are supported at different positions from each other on one side of the carrier and are configured to be rotatable and revolvable, and are arranged in n sets. The carrier is on the input side, the second sun gear is on the fixed side, the first sun gear is on the output side. Define Z1 as the number of teeth of the first sun gear and Z2 as the number of teeth of the second sun gear. If Z1 > Z2 and (Z1 - Z2) < Z2, the output of the first sun gear will be a deceleration in the same direction. If Z1 < Z2 and (Z2 - Z1) < Z1, the output of the first sun gear will be a deceleration in the opposite direction. If the first sun gear is changed to the input side and rotated while satisfying only one of the conditions for the deceleration to be executed, it will not be speeded up by the self-locking function, and the speed-up ratio will be 0 (zero) (the sun gear itself used as the input side is in a stopped state where it cannot rotate). This is the characteristic.

[0018] In the self-locking method of the speed reducer according to the present invention described above, the speed reducer includes a carrier that rotates as an input side, a first sun gear provided concentrically with the carrier, a first planetary gear meshing with the first sun gear, a second planetary gear meshing with the first planetary gear, a third planetary gear meshing with the second planetary gear, and a second sun gear that is concentric with the carrier, provided in parallel with the first sun gear, and meshes with the third planetary gear. The difference between the number of teeth of the first sun gear and the number of teeth of the second sun gear is at least one. The first, second, and third planetary gears are supported at different positions on one side of the carrier so as to be rotatable and revolvable, and are arranged in n sets. The carrier is the input side, the first sun gear is the fixed side, and the second sun gear is the output side. Let Z1 be defined as the number of teeth of the first sun gear and Z2 be defined as the number of teeth of the second sun gear. If Z1 < Z2 and (Z2 < Z1) < Z1, the output of the second sun gear will be a speed reduction in the same direction. If Z1 > Z2 and (Z1 - Z2) < Z2, the output of the second sun gear will be a speed reduction in the reverse direction. If the second sun gear is changed to the input side and rotated while satisfying only one of the conditions for executing the speed reduction, it will not be speeded up due to the self-locking function, and the speed increase ratio will be 0 (zero) (the sun gear itself used as the input side is in a stopped state where it cannot rotate).

[0019] On the other hand, in the self-locking method of the speed reducer according to another aspect of the present invention, the speed reducer includes a carrier that rotates as an input side, a first sun gear provided concentrically with the carrier, a first planetary gear meshing with the first sun gear, a second planetary gear meshing with the first planetary gear, a third planetary gear meshing with the second planetary gear, and a second sun gear that is concentric with the carrier, provided in parallel with the first sun gear, and meshes with the third planetary gear. The difference between the number of teeth of the first sun gear and the number of teeth of the second sun gear is at least one. The first, second, and third planetary gears are supported at different positions from each other on one side of the carrier and are configured to be rotatable and revolvable, and are arranged in n sets. The carrier is the input side, the second sun gear is the fixed side, and the first sun gear is the output side. Let Z1 be defined as the number of teeth of the first sun gear and Z2 be defined as the number of teeth of the second sun gear. If Z1>Z2 and (Z1-Z2)<Z2, the output of the first sun gear will be a speed reduction in the same direction. If Z1<Z2 and (Z2-Z1)<Z1, the output of the first sun gear will be a speed reduction in the reverse direction. If the first sun gear is changed to the input side and rotated while satisfying only one of the conditions for executing the speed reduction, it will not be speeded up due to the self-locking function, and the speed increase ratio will be 0 (zero) (the sun gear itself used as the input side cannot rotate and is in a stopped state).

Effects of the Invention

[0020] As described above, the present invention can realize various gear speed ratios from high ratio speed reduction to low ratio speed reduction in a speed reducer. The element of the ring gear is eliminated, and it consists only of external gears, eliminating the difficulty of manufacturing, reducing the space, and bringing about the effect of reducing the manufacturing cost. At the same time, due to the ease of processing, it is suitable for mass production. In addition, the self-locking function can prevent reverse rotation, so it has the advantages of easy control and can be used in various ways.

Brief Description of the Drawings

[0021]

Figure 1

Figure 2

Figure 3a

Figure 3b

Figure 4a

Figure 4b

Figure 5

Figure 6

Figure 7

Figure 8a

Figure 8b

Figure 8c

Figure 8d

Figure 8e

Figure 8f

Figure 9a

Figure 9b

Mode for Carrying Out the Invention

[0022] The above and other objects and novel features of the present invention will become more apparent from the description of this specification and the accompanying drawings.

[0023] Hereinafter, embodiments according to the present invention will be described with reference to the drawings.

[0024] FIG. 1 is a perspective view of a speed reducer having a self-locking function without a ring gear according to the present invention, and FIG. 2 is a perspective view showing a configuration of a linear tooth portion and n sets of planetary gears according to an embodiment of the present invention.

[0025] The speed reducer according to the present invention is a speed reducer that realizes a high ratio to a low ratio without a ring gear. As shown in FIGS. 1 and 2, a carrier 200 that rotates as an input side, a first sun gear 300 provided concentrically with the carrier 200, a first planetary gear 500 meshing with the first sun gear 300, a second planetary gear 600 meshing with the first planetary gear 500, a third planetary gear 700 meshing with the second planetary gear 600, and a second sun gear 400 that is concentric with the carrier 200, provided in parallel with the first sun gear 300, and meshes with the third planetary gear 700.

[0026] The difference between the number of teeth of the first sun gear 300 and the number of teeth of the second sun gear 400 is at least one. The first, second, and third planetary gears 500, 600, and 700 are supported at different positions from each other on one side of the carrier 200 and are configured to be rotatable and revolvable, and are arranged in n sets. The tip circle of the second planetary gear 600 is provided separately from the tip circles of the first sun gear 300 and the second sun gear 400. On the other hand, in FIG. 2, a configuration in which three sets of the first, second, and third planetary gears 500, 600, and 700 are provided is shown, but the present invention is not limited thereto, and two sets or four or more sets may be provided.

[0027] In the speed reduction device according to the present invention, as a first type, the carrier 200 may function as an input side, the first sun gear 300 may be fixed, and the second sun gear 400 may be provided so as to function as an output side. Further, in the planetary gear device according to the present invention, as a second type, the carrier 200 may be an input side, the second sun gear 400 may be fixed, and the first sun gear 300 may be provided so as to function as an output side.

[0028] Further, in the speed reduction device according to the present invention, the first and second sun gears 300 and 400 and the first, second, and third planetary gears 500, 600, and 700 may be provided with the same module.

[0029] On the other hand, in the speed reduction device according to the present invention, the first and second sun gears 300 and 400 and the first, second, and third planetary gears 500, 600, and 700 can also be provided in any one form of an involute tooth, a cycloidal tooth, a straight tooth portion, and a helical tooth portion.

[0030] Next, in the speed reduction device according to the present invention, the gear speed ratio and the self-lock function will be described with reference to FIGS. 3 and 4.

[0031] FIG. 3a is a cross-sectional view showing a first type gear speed ratio and a self-lock function according to an embodiment of the present invention, FIG. 3b is a cross-sectional view taken along the V-V line shown in FIG. 3a, FIG. 4a is a cross-sectional view showing a second type gear speed ratio and a self-lock function according to an embodiment of the present invention, and FIG. 4b is a cross-sectional view taken along the I-I line shown in FIG. 4a.

[0032] As shown in FIGS. 3a, 3b, 4a, and 4b, the speed reducer according to the present invention includes a carrier 200, a first sun gear 300, a second sun gear 400, a first planetary gear 500, a second planetary gear 600, and a third planetary gear 700. According to the input, output, and fixed positions of the carrier 200, the first sun gear 300, and the second sun gear 400, it is divided into a first type 800 shown in FIG. 3 and a second type 900 shown in FIG. 4 in terms of gear speed ratios. Different outputs in terms of direction and speed are obtained according to the number of teeth of the first sun gear 300 and the number of teeth of the second sun gear 400.

[0033] In the gear speed ratio of the first type 800, as shown in FIGS. 3a and 3b, when the carrier 200 connected to the input gear 190 rotates, the first planetary gear 500 supported by the carrier 200 rotates around the first sun gear 300 bolted to the fixed housing 101 by bolts 950 while rotating and revolving, and rotates the engaged second planetary gear 600. The second planetary gear 600 rotates the engaged third planetary gear 700, and the third planetary gear 700 rotates the engaged second sun gear 400, so that the shaft 103 rotates output together with the second sun gear 400. On the other hand, in FIG. 3, reference numeral 201 is a carrier rotation support base.

[0034] At this time, since the third planetary gear 700 rotates by the same number of teeth as the first planetary gear 500, when the carrier 200 makes one rotation, the rotation speed of the second sun gear 400 performs a deviation relative rotational motion by the difference in the number of teeth with respect to the fixed first sun gear 300, and the difference in the number of teeth between the first sun gear 300 and the second sun gear 400 becomes the difference in the rotation speeds between the input side and the output side. This is the gear speed ratio of the first type 800.

[0035] When expressing the gear speed ratio of the first type 800 shown in FIG. 3 by an equation, it is as shown in the following equation (1-1).

[0036]

Equation

[0037] (wherein, R1: gear speed ratio of the first type, Z1: number of teeth of the first sun gear, Z2: number of teeth of the second sun gear)

[0038] In the gear speed ratio of the first type 800, when the number of teeth of the second sun gear 400 is more than the number of teeth of the first sun gear 300, and the value obtained by subtracting the number of teeth of the first sun gear 300 from the number of teeth of the second sun gear 400 is less than the number of teeth of the first sun gear 300, the direction and speed of the output are decelerations in the same direction. When the number of teeth of the second sun gear 400 is more than the number of teeth of the first sun gear 300, and the value obtained by subtracting the number of teeth of the second sun gear 400 from the number of teeth of the first sun gear 300 is less than the number of teeth of the second sun gear 400, the direction and the speed of the output are decelerations in the opposite direction.

[0039] Summarizing the above content, When Z1 < Z2 and (Z2 - Z1) < Z1, the output is a deceleration in the same direction When Z1 > Z2 and (Z1 - Z2) < Z2, the output is a deceleration in the opposite direction (where, Z1: number of teeth of the first sun gear, Z2: number of teeth of the second sun gear) As shown in Table 1 below, in Example 1, when the number of teeth of the first sun gear 300 is 49 and the number of teeth of the second sun gear 400 is 50, the gear speed ratio is 50 / (50 - 49) = 50 / 1. When the input carrier 200 rotates 50 times, the output of the second sun gear 400 is 1 rotation, and a high ratio of reduction ratio is obtained, and the direction and speed are decelerations in the same direction.

[0040] Also, in Example 2, when the number of teeth of the first sun gear 300 is 50 and the number of teeth of the second sun gear 400 is 26, the gear speed ratio is 26 / (26 - 50) = (-1.08333). When the input carrier 200 rotates (-1.08333) times, the output of the second sun gear 400 is 1 rotation, and a low ratio of reduction ratio is obtained. (-) means the opposite direction, and the direction and speed are decelerations in the opposite direction.

[0041] When comparing this, it is as shown in Table 1. Table 1 shows the high ratio and low ratio of the first format according to the embodiment of the present invention.

[0042]

Table 1

[0043] In Table 1 above, the "-" sign means that the output with respect to the input rotation direction is reverse rotation. From Table 1, it can be easily understood that even if the number of teeth of the gear is slightly different, various gear ratios of high ratio reduction and low ratio reduction can be obtained. Here, when the second sun gear 400 is changed to the input side and rotated, the third planet gear 700 meshed with the second sun gear 400 rotates, and the third planet gear 700 rotates the second planet gear 600 that is meshed therewith, and the second planet gear 600 rotates the first planet gear 500 that is meshed therewith, and the first planet gear 500 rotates the first sun gear 300 that is meshed therewith.

[0044] At this time, since the first sun gear 300 is fixed and cannot be rotated, the first planet gear 500 tries to disengage from the meshing with the first sun gear 300, and a phenomenon occurs in which it tries to disengage from the support point supported by the carrier 200.

[0045] However, such a phenomenon cannot cause the first planet gear 500 to disengage from the support point of the carrier 200 and cannot disengage from the meshing with the first sun gear 300, so the rotation stops with the fixed first sun gear 300, and it is impossible to rotate by changing to the input side of the second sun gear 400, resulting in a self-locking function for reverse prevention where the speed increase ratio is 0 (zero) in a state where the speed increase of the stopped rotation 0 (zero) is impossible.

[0046] More specifically, when either one of the first or second sun gears is changed to the input side, even if a rotational input is applied to the sun gear, it will be in a stopped state where it cannot rotate.

[0047] Here, the specific reasons why the first planetary gear 500 does not rotate and power is not transmitted to the input of the second sun gear 400 are as follows.

[0048] The principle of the lever of the rotation of the self-rotation and revolution of a general planetary gear set is as shown in Fig. 9a.

[0049] In Fig. 9a, F represents force, W represents the point of action, A represents the fulcrum, and r1 and r2 represent distances respectively. The relational expression of the principle of the three levers is W×r1 = F×r2.

[0050] Here, the rotation of the carrier of a general planetary gear set is as shown in Fig. 9b.

[0051] In the general planetary gear set of Fig. 9b, when the ring gear is fixed and the sun gear is rotated clockwise, the F point in Fig. 9b moves to the right. The movement of the F point causes the planetary gear to rotate (counterclockwise) and decelerate while revolving clockwise concentrically around the ring gear.

[0052] The revolution of the planetary gear is as shown in Fig. 9b. The carrier supported by the planetary gear rotates. The revolution rotation of the planetary gear can be found from the principle of the second kind of lever. The instantaneous rotation center of the planetary gear in Fig. 9b is point A, which is the same as the fulcrum a in the second kind of lever. The F point of the planetary gear in Fig. 9b is the same as the force point F in the second kind of lever, and the W point of the planetary gear in Fig. 9b is the same as the point of action W in the second kind of lever.

[0053] As the force point F moves, the point of action W moves, and the continuous movement of the point of action becomes the rotation of the carrier. At this time, when calculating the force F, since the point of action W is the center of the planetary gear according to the relational expression of the principle of the second kind of lever, the force F becomes twice as large. Therefore, the revolution of the carrier can be smoothly rotated with a small force F.

[0054] On the other hand, when changing the carrier to the input side to increase the speed, by applying the principle of the third kind of lever, the center of the carrier becomes the force F, point A becomes the fulcrum, and the meshing part of the planetary gear and the sun gear becomes the action point W. It can be seen that the force F moving the action point W becomes twice as large. Comparing the cases of deceleration and acceleration, it can be seen that the rotational force F in the case of acceleration is even larger than in the case of deceleration, and the action point W is smaller.

[0055] Applying the interpretation of the rotation of self-rotation and revolution in a general reduction gear to the present invention, as shown in FIG. 5, when the first sun gear 300 of the present invention is on the fixed side and the second sun gear 400 is changed to the input side for self-rotation (clockwise direction), as shown in FIG. 5, the third planetary gear 700 and the first planetary gear 500 rotate counterclockwise. The counterclockwise self-rotation of the first planetary gear 500 revolves around the first sun gear 300, so that the supported carrier 200 also rotates counterclockwise.

[0056] However, in the content of the gear speed ratio of the first type 800 of the present invention, with the carrier 200 on the input side, the first sun gear 300 on the fixed side, and the second sun gear 400 on the output side, defining Z1 as the number of teeth of the first sun gear 300 and Z2 as the number of teeth of the second sun gear 400, if Z1 < Z2 and (Z2 - Z1) < Z1, the output of the second sun gear is a reduction in the same direction. Therefore, the clockwise rotation of the carrier 200 becomes the clockwise rotation of the second sun gear 400.

[0057] The principle interpretation of the self-lock of the present invention is as shown in FIG. 6 of the accompanying drawings. When the second sun gear 400 is fixed, as the first sun gear 300 rotates, the first planetary gear 500 tries to rotate. Since the second sun gear 400 is fixed, the meshing part of the first planetary gear 500 and the second sun gear 400 becomes the instantaneous rotation center A. The direction of the tangential force of the first planetary gear 500 has a separating tangential force F1 that rotates with respect to the instantaneous rotation center A and a rotational tangential force F2 that meshes with the second planetary gear 600.

[0058] For example, when calculating the rotational speed of each planetary gear, Let the number of teeth of the first sun gear 300 be Z1, Let the number of teeth of the second sun gear 400 be Z2, Let the number of teeth of the first planetary gear 500 be Z5, Let the number of teeth of the second planetary gear 600 be Z6, Let the number of teeth of the third planetary gear 700 be Z7, and when the carrier 200 rotates once as the input side and Z1 = 50, Z2 = 45, Z5 = 15, Z6 = 15, Z7 = 15, the rotational speed of the first planetary gear 500 is 1+(Z2 / Z5), which is 4 rotations, the rotational speed of the second planetary gear 600 is 1-(Z2 / Z6), which is 2 rotations, the rotational speed of the third planetary gear 700 is 1+(Z2 / Z7), which is 4 rotations, the rotational speed of the first sun gear 300 is 1-(Z2 / Z1), which is 1 / 10 rotation.

[0059] Here, when the first sun gear 300 is rotated in the opposite direction, the rotation of the first planetary gear 500 is 40 rotations, which is a speed increase, the rotation of the second planetary gear 600 is (-)20 rotations, which is a speed increase, the rotation of the third planetary gear 700 is 40 rotations and attempts to be speeded up.

[0060] However, in FIG. 6, with respect to the instantaneous rotation center A as a reference, the force F1 for the first planetary gear 500 to try to separate from the support base of the carrier is large, while the tangential force of F2 becomes a very small rotational force due to the speed increase.

[0061] Therefore, the first planetary gear 500 cannot rotate and stops. Since there is a phenomenon that the support point of the carrier 200 moves away from the center, it cannot rotate and remains in a stopped state, and the self-locking function is performed.

[0062] As shown in FIGS. 4A and 4B, when the carrier 200 rotates as the input side, the second planetary gear 600 that meshes rotates around the second sun gear 400 bolted to the housing cover 102 with the third planetary gear 700 supported by the carrier 200 fixed thereto, while rotating and revolving around the second sun gear 400. The second planetary gear 600 rotates the first planetary gear 500 that meshes therewith, and the first planetary gear 500 rotates the first sun gear 300 that meshes therewith. As a result, the shaft 103 rotates output together with the first sun gear 300.

[0063] At this time, since the first planetary gear 500 rotates by the same number of teeth as the third planetary gear 700, when the carrier 200 makes one revolution, the rotation speed of the first sun gear 300 makes a relative rotational movement deviation by the difference in the number of teeth with respect to the fixed second sun gear 400, and the difference in the number of teeth between the first sun gear 300 and the second sun gear 400 becomes the difference in the rotation speeds of the input and output. This is the gear speed ratio of the second type 900.

[0064] When the gear speed ratio of the second type 900 is expressed by an equation, it is as shown in the following equation (1-2).

[0065]

Number

[0066] (Here, R2: Gear speed ratio of the second type, Z1: Number of teeth of the first sun gear, Z2: Number of teeth of the second sun gear)

[0067] In the gear ratio of the second form 900, when the number of teeth of the first sun gear 300 is more than the number of teeth of the second sun gear 400, and the value obtained by subtracting the number of teeth of the second sun gear 400 from the number of teeth of the first sun gear 300 is less than the number of teeth of the second sun gear 400, the output direction and speed are decelerated in the same direction. When the number of teeth of the second sun gear 400 is more than the number of teeth of the first sun gear 300, and the value obtained by subtracting the number of teeth of the first sun gear 300 from the number of teeth of the second sun gear 400 is less than the number of teeth of the first sun gear 300, the output direction and speed are decelerated in the reverse direction. Summarizing the above content, When Z1 > Z2 and (Z1 - Z2) < Z2, the output is decelerated in the same direction When Z1 < Z2 and (Z2 - Z1) < Z1, the output is decelerated in the reverse direction (Here, Z1: the number of teeth of the first sun gear, Z2: the number of teeth of the second sun gear) For example, as shown in Table 2 below, in Example 5, when the number of teeth of the first sun gear 300 is 100 and the number of teeth of the second sun gear 400 is 99, the gear ratio is 100 / (100 - 99) = 100 / 1. When the input carrier 200 rotates 100 times, the output of the first sun gear 300 rotates 1 time, obtaining a high-ratio reduction ratio, and the direction and speed are decelerated in the same direction.

[0068] Also, in Example 6, when the number of teeth of the first sun gear 300 is 51 and the number of teeth of the second sun gear 400 is 100, the gear ratio is 51 / (51 - 100) = (-1.0408). When the input carrier 200 rotates (-1.0408) times, the output of the first sun gear 300 rotates 1 time, obtaining a low-ratio reduction ratio, and (-) means the reverse direction, and the direction and speed are decelerated in the reverse direction.

[0069] Comparing this, it is as shown in Table 2. Table 2 shows examples of high ratios and low ratios of the second form according to the embodiment of the present invention

[0070]

Table 2

[0071] In Table 2 above, the "-" sign means that the output with respect to the input rotation direction is reverse rotation.

[0072] From Table 2 above, it can be easily seen that even if the number of teeth of the gear is slightly different, high-ratio deceleration and low-ratio deceleration can be achieved.

[0073] Here, when the first sun gear 300 is changed to the input side and rotated, the first planet gear 500 meshing with the first sun gear 300 starts to rotate. The first planet gear 500 rotates the second planet gear 600 with which it is meshing, and the second planet gear 600 rotates the third planet gear 700 with which it is meshing. The third planet gear 700 rotates the second sun gear 400 with which it is meshing.

[0074] At this time, since the second sun gear 400 is fixed and cannot be rotated, the third planet gear 700 tries to disengage from the meshing with the second sun gear 400 and tries to separate from the support point supported by the carrier 200.

[0075] However, such a phenomenon cannot cause the third planet gear 700 to disengage from the support point of the carrier 200 or from the meshing with the second sun gear 400. Therefore, the rotation stops at the fixed second sun gear 400, and it is impossible to change the first sun gear 300 to the input side and rotate it. This results in a reverse prevention self-lock function where the speed increase ratio is 0 (zero) (the sun gear itself used as the input side is in a non-rotating stopped state) in a state where it is impossible to increase the speed from the stopped rotation of 0.

[0076] More specifically, when either one of the first or second sun gears is changed to the input side, even if a rotational input is applied to the sun gear, it will be in a non-rotating stopped state.

[0077] Here, since the reverse prevention self-locking function in which the third planet gear 700 does not rotate and power is not transmitted to the input of the first sun gear 300 is as shown in FIG. 6, it will be omitted without specific mention.

[0078] In the planetary gear device according to the present invention, the above-described gears 300, 400, 500, 600, 700 can adjust the center distance and can be manufactured without any restrictive conditions for either standard gears or modified gears, and since it consists only of external gears, it shows that any ordinary technician can easily manufacture it. That is, the number of teeth of each gear can be selected to manufacture the gears, and it is possible to select the number of sets of the first, second, and third planet gears 500, 600, 700 and their equally spaced arrangement. In the speed reduction device according to the present invention, not only is the gear speed ratio determined according to the number of teeth of the first sun gear 300 and the number of teeth of the second sun gear 400, but there is also a correlation with the equally spaced arrangement of the number of sets of planet gears. Therefore, if the value obtained by subtracting the number of teeth of the second sun gear 400 from the number of teeth of the first sun gear 300 is specified as a multiple of the number of sets n of planet gears, the number of teeth of the first sun gear 300 and the number of teeth of the second sun gear 400 can be determined as shown in the following formula (1-3).

[0079] [Number]

[0080] (Here, Z1: number of teeth of the first sun gear, Z2: number of teeth of the second sun gear, n: number of sets of planet gears)

[0081] Generally, in order to arrange the planet gears at equal intervals in n (1, 2, 3, 4, 5) sets, the number of teeth Z1 of the first sun gear 300 is set to an arbitrary value, the number of sets of planet gears is made a multiple of n, and an approximate value of the target gear ratio is searched and selected. Then, the number of teeth Z2 of the second sun gear 400 is determined by formula (1-3), and the number of teeth of the first, second, and third planet gears 500, 600, 700 can be freely selected to have the same number of teeth so that the sets do not overlap.

[0082] For example, as in the embodiment shown in FIG. 7, when the number of sets of planetary gears is set to n = 3, the number of teeth of the first sun gear 300 is arbitrarily set to 50 and the number of teeth of the second sun gear 400 is selected, according to the formula (1-3), n has positive multiples such as 3, 6, 9, 12, and negative multiples such as -3, -6, -9, -12, etc. FIG. 7 is a front view showing the arrangement of n sets of planetary gears arranged at equal intervals according to an embodiment of the present invention.

[0083] Therefore, if the number of teeth of the second sun gear 400 is selected based on positive multiples, there are 53, 56, 59, 62, etc., and if selected based on negative multiples, there are 47, 44, 41, 38, etc. From these, the number of teeth that matches the approximate value of the target gear ratio may be selected.

[0084] In the embodiment as shown in FIG. 7, the number of teeth of the second sun gear 400 is selected to be 41, and the number of teeth of the first, second, and third planetary gears 500, 600, 700 of the first set are arbitrarily selected to be 15, 15, and 21 respectively. Since the number of teeth of the first, second, and third planetary gears 500, 600, 700 of the second set must be the same as those of the planetary gears 500, 600, 700 of the first set, they are selected to be 15, 15, and 21 respectively, and the number of teeth of the first, second, and third planetary gears 500, 600, 700 of the third set may also be 15, 15, and 21 respectively. Here, the number of teeth of the planetary gears can be freely selected arbitrarily, such as 12, 13, 14, 15, ···, 20, 21, ···, 32, 33, etc., but it must be manufactured without problems such as gear tooth overlap and meshing with other parts in parts not shown in the embodiment. This is an obvious content for any ordinary engineer in the same field, so it is omitted without specific mention.

[0085] Furthermore, for example, assuming the number of sets of the first, second, and third planetary gears 500, 600, and 700 is n = 5, arbitrarily setting the number of teeth of the second sun gear 400 to 51, and selecting the number of teeth of the first sun gear 300, according to the formula (1-3), the positive multiples of the number of sets 5 are 5, 10, 15, etc., and the negative multiples are -5, -10, -15, etc. Therefore, if the positive multiple is applied to select the number of teeth of the first sun gear 300, it will be 56, 61, 66, ···, etc., and if the negative multiple is applied to select the number of teeth of the first sun gear 300, it will be 46, 41, 36, ···, etc. Then, the number of teeth that matches the approximate value of the target gear ratio can be selected from these. Here too, the number of teeth of the planetary gear can be freely selected as described above.

[0086] Next, with reference to FIG. 8, the meshing of the gear teeth according to the number of sets of planetary gears will be described.

[0087] FIG. 8a is a front view showing the arrangement of n sets of planetary gears after the change of the included angle according to an embodiment of the present invention, FIG. 8b is a front view showing the impossibility of gear tooth meshing before the change of the included angle according to an embodiment of the present invention, FIG. 8c is a side view showing the side surface according to FIG. 8a, FIG. 8d is a cross-sectional view shown by cutting along the W-W line according to FIG. 8c, and FIG. 8f is a front view showing the position of the included angle according to an embodiment of the present invention. Also, in FIG. 8, A indicates the normal position of gear tooth meshing, B indicates the impossible position of gear tooth meshing, and C indicates the impossible position of gear tooth meshing.

[0088] In the embodiment shown in FIG. 8a, it shows that the number of teeth of the first sun gear 300 is 50, the number of teeth of the second sun gear 400 is 49, and the number of sets of planetary gears n = 3, indicating accurate gear tooth meshing between the gears.

[0089] Since the difference in the number of teeth between the first sun gear 300 and the second sun gear 400 is one, one set of planetary gears must be arranged according to the formula (1-3). However, as shown in FIGS. 8b to 8f, when three sets are arranged at equal intervals, as shown in FIG. 8b, there is no problem with the meshing of the gear teeth only at the A position of the first set, and problems occur at the B position of the second set and the C position of the third set where the meshing of the gear teeth is impossible and assembly cannot be carried out.

[0090] Also, when the difference in the number of teeth of the sun gear is one as described above, even though the gear speed ratio is maximized, when only one set of planetary gears is arranged, there is no problem at low speeds, but at high speeds, excessive vibration occurs and durability decreases, resulting in problems.

[0091] Therefore, in order to solve such problems, as in the embodiment shown in FIG. 8f, the "included angle change" of the straight line connecting the centers of the gears in the carrier 200 is used to determine the number of sets of planetary gears n that is not related to the conditions of the formula (1-3), which will be described below.

[0092] First, the "included angle change" is, as shown in FIG. 8f, to change the angle sandwiched between the straight lines connecting the centers of the gears at the first set position or the second set position or the third set position in the carrier 200. Taking the second planetary gear 600 at the first set position as a reference, for example, it is to change the angle A03 sandwiched between the straight line connecting the center of the first planetary gear 500 to the center of the second planetary gear and the straight line connecting the center of the third planetary gear to the center of the second planetary gear.

[0093] As shown in Fig. 8f, there are four positions A01, A02, A03, and A04 at the first set position for the "included angle", and there are also four positions B01, B02, B03, and B04 at the second set position, and there are four positions C01, C02, and C03 at the third set position. In Fig. 8f, A01 indicates the included angle between the straight line connecting from the center of the third planetary gear at the first set position to the center of the carrier and the straight line connecting from the center of the first planetary gear to the center of the carrier; A02 indicates the included angle between the straight line connecting from the center of the carrier at the first set position to the center of the first planetary gear and the straight line connecting from the center of the first planetary gear to the center of the carrier; A03 indicates the included angle between the straight line connecting from the center of the first planetary gear at the first set position to the center of the second planetary gear and the straight line connecting from the center of the third planetary gear to the center of the second planetary gear; A4 indicates the included angle between the straight line connecting from the center of the carrier at the first set position to the center of the third planetary gear and the straight line connecting from the center of the second planetary gear to the center of the third planetary gear.

[0094] Also, B01 indicates the included angle between the straight line connecting from the center of the third planetary gear at the second set position to the center of the carrier and the straight line connecting from the center of the first planetary gear to the center of the carrier; B02 indicates the included angle between the straight line connecting from the center of the carrier at the second set position to the center of the first planetary gear and the straight line connecting from the center of the first planetary gear to the center of the carrier; B03 indicates the included angle between the straight line connecting from the center of the first planetary gear at the second set position to the center of the second planetary gear and the straight line connecting from the center of the third planetary gear to the center of the second planetary gear; B04 indicates the included angle between the straight line connecting from the center of the carrier at the second set position to the center of the third planetary gear and the straight line connecting from the center of the second planetary gear to the center of the third planetary gear.

[0095] Further, C01 represents the included angle between the straight line connecting the center of the third planetary gear at the third set position to the center of the carrier and the straight line connecting the center of the first planetary gear to the center of the carrier; C02 represents the included angle between the straight line connecting the center of the carrier at the third set position to the center of the first planetary gear and the straight line connecting the center of the first planetary gear to the center of the carrier; C03 represents the included angle between the straight line connecting the center of the first planetary gear at the third set position to the center of the second planetary gear and the straight line connecting the center of the third planetary gear to the center of the second planetary gear; C04 represents the included angle between the straight line connecting the center of the carrier at the third set position to the center of the third planetary gear and the straight line connecting the center of the second planetary gear to the center of the third planetary gear.

[0096] Among these set positions, in a set where the gear teeth cannot mesh, if one of the four included angles is changed, the problem of impossible gear tooth meshing can be solved. Also, regardless of the number of teeth of the first sun gear 300 and the second sun gear 400 in the formula (1-3), the number of sets of planetary gears can be increased or decreased.

[0097] For example, as shown in the embodiment of FIG. 8b, the portions where the gear teeth cannot mesh are the B portion at the second set position and the C portion at the third set position. Therefore, for the B portion at the second set position, one of the included angles of B01, B02, B03, or B04 at the second set position in FIG. 8f can be changed; for the C portion at the third set position in FIG. 8b, one of the included angles of C01, C02, C03, or C04 at the third set position in FIG. 8f can be changed.

[0098] To give a more specific example of the C part in the third set position, when the center of the second planetary gear 600 at the third set position supported by the carrier 200 is moved in the direction opposite to the center of the carrier 200, while the included angle (C03) between the straight line connecting the center of the first planetary gear 500 to the center of the second planetary gear 600 and the straight line connecting the center of the third planetary gear 700 to the center of the second planetary gear 600 is changed, the second planetary gear 600 rotates around the first planetary gear 500, and the engaged third planetary gear 700 also rotates. By rotating and moving only the tooth thickness part where gear tooth engagement was impossible, it meshes to fit into the tooth space of the mating gear.

[0099] In the "included angle change", if the number of sets of planetary gears is n, only the interference occurrence part of the gear teeth is changed in the remaining set number except for one set where the meshing is accurately performed. The part that requires the "included angle change" is at most n - 1. Here, as mentioned in the above explanation, at the first, second, and third set positions, four included angles are formed respectively, and only one of the four included angles for each set needs to be changed.

[0100] This is because when one included angle is determined or changed by "trigonometric functions" and "the second cosine theorem", the remaining included angles are automatically determined or changed.

[0101] In the embodiments shown in FIGS. 8b and 8e, for the non - meshing parts of the gear teeth in the B part and the C part, the interference problem of gear tooth meshing is solved by changing the included angle between B02 and C02 in FIG. 8f. The included angle of B02 is changed from 97 degrees before the change to 95.4 degrees after the change, and the included angle of C02 is changed from 97 degrees before the change to 98.6 degrees after the change. It can be confirmed that the problem of impossible gear tooth meshing can be solved by the "included angle change", and the number of sets of planetary gears can be increased or decreased.

[0102] As an embodiment, not only the angle change between the B02 and the C02, but also the 97 degrees before the angle change, 98.6 degrees and 95.4 degrees after the angle change are not values limited to the values of the embodiment. Since they are values that change according to the increase or decrease in the number of teeth of the sun gear and the number of sets of planetary gears, and the change in the position of the planetary gears, they are not limited to the embodiment.

[0103] Summarizing the technology of the present invention, it is a speed reduction device with a self-locking function realized from a high ratio to a low ratio without a ring gear, including a carrier that rotates as an input side, a first sun gear provided concentrically with the carrier, a first planetary gear meshing with the first sun gear, a second planetary gear meshing with the first planetary gear, a third planetary gear meshing with the second planetary gear, and a second sun gear that is concentric with the carrier, provided in parallel with the first sun gear, and meshing with the third planetary gear. The difference between the number of teeth of the first sun gear and the number of teeth of the second sun gear is at least one. The first, second, and third planetary gears are supported at different positions from each other on one side of the carrier and are configured to be rotatable and revolvable, and are arranged in n sets. When either one of the first sun gear or the second sun gear is fixed and the remaining one sun gear is changed to the input side, it is not speeded up by the self-locking function, and the speed increase ratio becomes 0 (zero).

[0104] To realize the self-locking function, the carrier is the input side, the first sun gear is the fixed side, the second sun gear is the output side. Define Z1 as the number of teeth of the first sun gear and Z2 as the number of teeth of the second sun gear. If Z1 < Z2 and (Z2 - Z1) < Z1, the output of the second sun gear is decelerated in the same direction. If Z1 > Z2 and (Z1 - Z2) < Z2, the output of the second sun gear is decelerated in the reverse direction. While satisfying only one of the conditions for executing the deceleration, when the second sun gear is changed to the input side and rotated, it is not speeded up by the self-locking function, and the speed increase ratio becomes 0 (zero).

[0105] Also, the carrier is on the input side, the second sun gear is on the fixed side, and the first sun gear is on the output side. Define Z1 as the number of teeth of the first sun gear and Z2 as the number of teeth of the second sun gear. If Z1>Z2 and (Z1-Z2)<Z2, the output of the first sun gear is a reduction in the same direction. If Z1<Z2 and (Z2-Z1)<Z1, the output of the first sun gear is a reduction in the reverse direction. If the first sun gear is changed to the input side and rotated while satisfying only one of the conditions for the reduction to be executed, it will not be speeded up by the Self-Locking function, and the speed-up ratio will be 0 (Zero).

[0106] Therefore, in the speed reducer with the structure where the reduction of the present invention is performed, if the output side is changed to the input side and used, it will not be speeded up by the Self-Locking function, and the speed-up ratio will be 0 (Zero), that is, it will become an inoperable device.

[0107] As described above, the present invention can realize various gear speed ratios from high ratio reduction to low ratio reduction in a speed reduction device. The ring gear element is eliminated, and it consists only of external gears, eliminating the difficulty of manufacturing, reducing space, and bringing about the effect of reducing manufacturing costs. On the other hand, due to the ease of processing, it is suitable for mass production. Also, since reverse rotation can be prevented by the Self-Locking function, the advantage is that control is easy and it can be utilized in various ways.

[0108] As described above, it can be seen that the basic technical idea of the present invention is to provide a speed reduction device with a Self-Locking function that is realized from a high ratio to a low ratio without a ring gear. Of course, many other modifications are possible for those with ordinary knowledge in the technical field within the scope of such a basic idea of the present invention.

Explanation of Reference Numerals

[0109] 101 Fixed housing 102 Fixed housing cover 150 Bearing 200 carriers 201 carrier rotation support stand 300 first sun gear 400 second sun gear 500 first planetary gear 600 second planetary gear 700 third planetary gear 800 first type gear ratio 900 second type gear ratio 950 bolt

Claims

1. A self-locking method for a speed reduction device, comprising: a carrier rotating as an input side, a first sun gear provided concentrically with the carrier, a first planetary gear meshing with the first sun gear, a second planetary gear meshing with the first planetary gear, a third planetary gear meshing with the second planetary gear, and a second sun gear that is concentric with the carrier, provided in parallel with the first sun gear, and meshing with the third planetary gear; the difference between the number of teeth of the first sun gear and the number of teeth of the second sun gear is at least one, and the first, second, and third planetary gears are supported at different positions on one side of the carrier so as to be rotatable and revolvable, and are arranged in n sets; the carrier is the input side, the first sun gear is the fixed side, the second sun gear is the output side, Z1 is defined as the number of teeth of the first sun gear, and Z2 is defined as the number of teeth of the second sun gear; if Z1 < Z2 and (Z2 - Z1) < Z1, the output of the second sun gear is a speed reduction in the same direction; if Z1 > Z2 and (Z1 - Z2) < Z2, the output of the second sun gear is a speed reduction in the reverse direction; If the second sun gear is changed to the input side and rotated while satisfying only one of the conditions for executing the speed reduction, the speed is not increased by the self-locking function, and the speed increase ratio becomes 0 (zero) (the sun gear itself used as the input side cannot rotate and is in a stopped state). A self-locking method for a speed reduction device without a ring gear, characterized in that.

2. A self-locking method for a speed reduction device, comprising: a carrier rotating as an input side, a first sun gear provided concentrically with the carrier, a first planetary gear meshing with the first sun gear, a second planetary gear meshing with the first planetary gear, a third planetary gear meshing with the second planetary gear, and a second sun gear that is concentric with the carrier, provided in parallel with the first sun gear, and meshing with the third planetary gear; the difference between the number of teeth of the first sun gear and the number of teeth of the second sun gear is at least one, and the first, second, and third planetary gears are supported at different positions on one side of the carrier so as to be rotatable and revolvable, and are arranged in n sets. The carrier is the input side, the second sun gear is the fixed side, the first sun gear is the output side, Z1 is defined as the number of teeth of the first sun gear, and Z2 is defined as the number of teeth of the second sun gear; If Z1 > Z2 and (Z1 - Z2) < Z2, the output of the first sun gear will be decelerated in the same direction. If Z1 < Z2 and (Z2 - Z1) < Z1, the output of the first sun gear will be decelerated in the reverse direction. A self-locking method for a reduction gear without a ring gear, characterized in that if the first sun gear is changed to the input side and rotated while satisfying only one of the conditions for executing the deceleration, it will not be speeded up by the self-locking function, and the speed-up ratio will be 0 (Zero) (a stopped state where the sun gear used as the input side itself cannot rotate).

3. A reduction gear, including a carrier rotating as the input side, a first sun gear provided concentrically with the carrier, a first planetary gear meshing with the first sun gear, a second planetary gear meshing with the first planetary gear, a third planetary gear meshing with the second planetary gear, and a second sun gear that is concentric with the carrier, provided in parallel with the first sun gear, and meshing with the third planetary gear. The difference between the number of teeth of the first sun gear and the number of teeth of the second sun gear is at least one, and the first, second, and third planetary gears are supported at different positions on one side of the carrier so as to be rotatable and revolvable, and are arranged in n sets. The carrier is the input side, the first sun gear is the fixed side, the second sun gear is the output side, Z1 is defined as the number of teeth of the first sun gear, and Z2 is defined as the number of teeth of the second sun gear. If Z1 < Z2 and (Z2 - Z1) < Z1, the output of the second sun gear will be decelerated in the same direction. If Z1 > Z2 and (Z1 - Z2) < Z2, the output of the second sun gear will be decelerated in the reverse direction. A reduction gear having a self-locking function without a ring gear, characterized in that if the second sun gear is changed to the input side and rotated while satisfying only one of the conditions for executing the deceleration, it will not be speeded up by the self-locking (Self-Locking) function, and the speed-up ratio will be 0 (Zero) (a stopped state where the sun gear used as the input side itself cannot rotate).

4. A reduction gear, including a carrier rotating as the input side, a first sun gear provided concentrically with the carrier, a first planetary gear meshing with the first sun gear, a second planetary gear meshing with the first planetary gear, a third planetary gear meshing with the second planetary gear, and a second sun gear that is concentric with the carrier, provided in parallel with the first sun gear, and meshing with the third planetary gear. The difference between the number of teeth of the first sun gear and the number of teeth of the second sun gear is at least one, and the first, second, and third planetary gears are supported at different positions on one side of the carrier so as to be rotatable and revolvable, and are arranged in n sets. The carrier is the input side, the second sun gear is the fixed side, the first sun gear is the output side, Z1 is defined as the number of teeth of the first sun gear, and Z2 is defined as the number of teeth of the second sun gear. If Z1 > Z2 and (Z1 - Z2) < Z2, the output of the first sun gear will be a reduction in the same direction. If Z1 < Z2 and (Z2 - Z1) < Z1, the output of the first sun gear will be a reduction in the reverse direction. A speed reduction device having a self-locking function without a ring gear, characterized in that if the first sun gear is changed to the input side and rotated while satisfying only one of the conditions for executing the speed reduction, it will not be speeded up by the self-locking function, and the speed increase ratio will be 0 (zero) (a stopped state where the sun gear used as the input side itself cannot rotate).

Images