JP2012149741A - Eccentric rocking type reduction gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin eccentric rocking type reduction gear that can set a transmission torque of each external gear to a desired value.SOLUTION: In the eccentric rocking type reduction gear 1 with an internal gear 21 and first and second external gears 5 and 6 meshing with the internal gear 21, an output pin includes a first output pin 7 coming into contact only with a through-hole 51 of the first external gear 5 and a second output pin 8 coming into contact only with a through-hole 61 of the second external gear 6. The transmission torque is set so as to satisfy an expression KR=CKRwhere C denotes a desired value of a ratio of the transmission torque of the first external gear 5 to the transmission torque of the second external gear 6, Kdenotes a value of first stiffness that is a stiffness of the first output pin 7, Kdenotes a value of second stiffness that is a stiffness of the second output pin 8, Rdenotes a distance between the center of the internal gear 21 and the center of the first output pin, and Rdenotes a distance between the center of the internal gear 21 and the center of the second output pin.

Description

  The present invention relates to an eccentric oscillating speed reducer, and more specifically, an eccentric oscillating type capable of setting a transmission torque acting on an output pin of an eccentric oscillating speed reducer having a plurality of external gears to a desired value. It relates to a reduction gear.

  In order to increase the rigidity of the output pin that takes out the rotation of the external gear to the output shaft and to equalize the load transmitted from the external gear, the conventional technique 1 (for example, using the output pin as a double-supported support) Patent Document 1). Further, in the eccentric oscillating type reduction gear in which the output pin is cantilevered by the output shaft, in order to avoid the load from being concentrated on a part of the output pins, the prior art 2 (for example, patent) Reference 2).

Japanese Utility Model Publication No.59-127951 Japanese Utility Model Publication No. 4-32518

In prior art 1 of Patent Document 1, since a support ring is added and the output pin is supported at both ends, the axial direction of the eccentric oscillating speed reducer is accompanied by an increase in the size of the space in which the support ring is provided in the axial direction. There was a limit to thinning.
Prior art 2 of Patent Document 2 can eliminate load imbalance between output pins contacting the same external gear. However, since the output pin diameter is the same and is cantilevered, the load differs between the output pin contact portion of the external gear close to the output shaft and the output pin contact portion of the remote external gear. This is because the bending rigidity resulting from the bending deformation of the output pin is inversely proportional to the cube of the distance from the output pin support portion to the load application point. For this reason, since the contact portion of the external gear close to the output shaft has high rigidity, a large load is applied, and a small load is applied to the contact portion of the external gear far from the output shaft having low rigidity. Eventually, the transmission torque of the external gear close to the output shaft is large and the transmission torque of the external gear distant from the output shaft is small, and the maximum transmission torque of the reduction gear is regulated by the strength limit of the external gear close to the output shaft.
The present invention has been made in view of the above circumstances, and provides an eccentric oscillating speed reducer that can set a transmission torque of each external gear to a desired value and is thin with respect to the rotation axis direction. For the purpose.

In order to solve the above problems, the invention according to claim 1 is characterized in that an internal gear, first and second external gears meshed with the internal gear, and the first and second external gears are connected to a crankshaft. The crankshaft that is revolved with respect to the central axis of the internal gear by two eccentric cylindrical cam portions arranged at different positions around the axis of the internal gear, and the first and second external gears. A plurality of output pins in contact with a through hole parallel to the central axis of the internal gear, a rotation shaft that holds one end of the output pin and is rotatable with respect to the central axis of the internal gear, and the crankshaft serves as an input shaft. In the eccentric oscillating speed reducer that rotates with the internal gear and the rotating shaft as an output shaft,
The output pin comprises a first output pin that contacts only the through hole of the first external gear, and a second output pin that contacts only the through hole of the second external gear,
The desired value of the ratio of the transmission torque of the first external gear to the transmission torque of the second external gear is C, the first stiffness value that is the stiffness of the first output pin is K ₁ , and the second output pin The value of the second rigidity, which is the rigidity of the first output pin, is K ₂ , the distance from the center axis of the internal gear at the center of the first output pin is R ₁ , and the distance from the center axis of the internal gear at the center of the second output pin is R ₂ is set to satisfy the formula K ₁ · R ₁ ² = C · K ₂ · R ₂ ² ,
The first rigidity is a rigidity between a contact portion of the first output pin with the first external gear in a direction orthogonal to a central axis of the internal gear and an axial center portion of the rotation shaft, and the second The rigidity is a rigidity between a contact portion of the second output pin with the second external gear in a direction orthogonal to a central axis of the internal gear and an axial center portion of the rotary shaft.

  A feature of the invention according to claim 2 is that, in the invention according to claim 1, the distance from the support point of the second output pin to the contact point of the second external gear with the through hole is the first output pin. The distance from the support point to the contact point of the first external gear with the through hole is made longer, and the diameter of the second output pin is made larger than the diameter of the first output pin.

  A feature of the invention according to claim 3 is that in the invention according to claim 2, the diameter of the contact portion of the second output pin with the through hole of the second external gear is set to It is to make it smaller than the diameter.

  According to a fourth aspect of the present invention, in the invention according to the third aspect, the diameter of the contact portion of the second output pin with the through hole of the second external gear is the diameter of the first output pin. It is to be the same.

  A feature of the invention according to claim 5 is that, in the invention according to claim 1, the diameters of the first output pin and the second output pin are the same.

A feature of the invention according to claim 6 is that, in the invention according to any one of claims 1 to 5, the contact point between the support point of the second output pin and the through hole of the second external gear. Is longer than the distance from the support point of the first output pin to the contact point with the through hole of the first external gear, and R ₂ is made larger than R ₁ .

  A feature of the invention according to claim 7 is that, in the invention according to any one of claims 1 to 6, the width of the second external gear is made smaller than the width of the first external gear. .

  A feature of the invention according to claim 8 is that, in the invention according to any one of claims 1 to 7, the longitudinal elastic modulus of the material of the first output pin and the longitudinal elastic modulus of the material of the second output pin. Is different.

According to the invention of claim 1, the value C of the ratio of the transmission torque of the first external gear to the transmission torque of the second external gear can be set as desired. For example, when the maximum permissible transmission torque of the first external gear is twice the maximum permissible transmission torque of the second external gear, C = 2 and the equation K ₁ · R ₁ ² = C · K ₂ · R ₂ ² The first stiffness value K ₁ , the second stiffness value K ₂ , the distance R ₁ from the central axis of the internal gear at the center of the first output pin, and the central axis of the internal gear at the center of the second output pin so as to satisfy to set the distance _{R 2.} In this way, the ratio of the transmission torque of the first external gear to the transmission torque of the second external gear is 2, and the sum of the maximum allowable transmission torques of the first and second external gears is set to Maximum transmission torque. Both the first and second external gears can transmit torque without waste. As a result, the transmission torque can be increased or the eccentric oscillating speed reducer can be downsized.

According to the second aspect of the invention, it is easy to make the first stiffness value K ₁ and the second stiffness value K ₂ equal, and the transmission torque of the first external gear and the transmission of the second external gear. Easily realize an eccentric oscillating speed reducer with the same torque.

According to the invention of claim 3, without reducing significantly the value K ₂ of the second rigid, since the through hole diameter of the second external gear can be reduced, the meat of the outer periphery of the through hole of the second external gear The thickness increases, the strength increases, and the transmission torque by the second external gear can be increased.

  According to the invention which concerns on Claim 4, since the through-hole diameter of a 1st, 2nd output pin is the same, the through-hole provided in the 1st, 2nd external gear can be processed with the same tool, and processing time can be shortened.

  According to the invention of claim 5, since the diameters of the first and second output pins are the same, the output pin mounting hole of the rotary shaft and the through hole provided in the first and second external gears can be processed with the same tool. Processing time can be shortened.

  According to the invention of claim 6, when the transmission torque of the first external gear and the transmission torque of the second external gear are equal, the value of the second rigidity can be made smaller than the value of the first rigidity. The degree of making the diameter of the second output pin larger than the diameter of the first output pin can be reduced. For this reason, the outer diameter of the eccentric oscillation type reduction gear can be made small.

According to the invention of claim 7, since the allowable transmission torque than the allowable transmission torque of the first external gear second external gear is reduced, it is possible to reduce the K ₂ · R ₂ ² relating to the second external gear, The outer diameter of the eccentric oscillating speed reducer can be reduced.

  According to the eighth aspect of the present invention, the first and second stiffness values are determined by two factors, the difference in shape between the first and second output pins and the difference in the longitudinal elastic modulus of the material of the first and second output pins. It can be set, and the setting range of the rigidity value becomes wide. Further, if the longitudinal elastic modulus of the second output pin is made larger than that of the first output pin, an increase in the diameter of the second output pin can be reduced. As a result, an increase in the outer diameter of the external gear can be reduced, and the outer diameter of the eccentric oscillating speed reducer can be reduced.

It is sectional drawing of the eccentric rocking | fluctuation type reduction gear of 1st Embodiment (CC cross section of FIG. 2). It is AA sectional drawing of FIG. It is BB sectional drawing of FIG. It is a figure which shows the relationship between the position of an output pin, and transmission torque. It is a conceptual diagram which shows the displacement of the output pin 7 (DD cross section of FIG. 4). 3 is a conceptual diagram showing displacement of an output pin 8. FIG. It is sectional drawing of the eccentric rocking | swiveling type reduction gear of 2nd Embodiment. It is sectional drawing of the eccentric rocking | swiveling type reduction gear of 3rd Embodiment.

Hereinafter, a first embodiment of the present invention will be described based on FIGS. 1 to 5 with an example in which an internal gear is fixed and a rotary shaft is an output shaft.
As shown in FIG. 1, the eccentric oscillating speed reducer 1 includes a rotating shaft 4 that is rotatably supported by a bearing 13 held by a housing 2. At the center of the housing 2, there is provided a crankshaft 3 rotatably supported at both ends via a bearing 12 held by the rotary shaft 4 and a bearing 9 held by the housing 2. The crankshaft 3 includes cylindrical eccentric cam portions 31 and 32 at the center, and the eccentric cam portions 31 and 32 have an eccentricity amount e with respect to the rotational axis a of the crankshaft 3 and are substantially 180 degrees out of phase with each other. . An external gear 5 that is a first external gear rotatably supported on the outer periphery of the eccentric cam portion 31 via the bearing 11 is provided, and is rotatably supported on the outer periphery of the eccentric cam portion 32 via the bearing 10. An external gear 6 that is a second external gear is provided. A plurality of output pins 7 as first output pins are press-fitted and held on the rotary shaft 4 so that the axis is parallel to the rotary axis a at the concentric circumferential position of the rotary axis a. The output pin 7 is inscribed in a through hole 51 provided in the external gear 5. A plurality of output pins 8 that are second output pins are arranged at a concentric circumferential position of the rotation axis a so that the axis is parallel to the rotation axis a, and one end of the output pin 8 is press-fitted and held on the rotation shaft 4. Yes. The output pin 8 penetrates through the hole 52 provided in the external gear 5 in a non-contact manner, and the contact portion 81 having a smaller diameter than the press-fit portion provided at the other end of the output pin 8 is provided in the external gear 6. Inscribed in the hole 61.
Here, the rotation axis a coincides with the center line of the internal gear 21 provided on the inner peripheral surface of the housing 2, and the tooth shapes of the internal gear 21 and the external gears 5 and 6 are involute tooth shapes.

As shown in FIGS. 2 and 3, the external gears 5 and 6 have a gear pitch circle diameter that meshes with the internal gear 21 at one location. As the crankshaft 3 rotates, the external gears 5 and 6 revolve with the radius of the eccentric amount e of the crankshaft 3 while meshing with the internal gear 21. As shown in FIG. 2, the hole diameter d ₁ of the through hole 51 of the external gear 5 is set to d ₁ = 2 · e + D ₁ when the outer diameter of the output pin 7 is D _1. The pin 7 always rotates in contact with the outer periphery. As shown in FIG. 3, the hole diameter d ₂ of the through hole 61 of the external gear 6 is set to the outer diameter of the contact portion 81 of the output pin 8 to _{d 2 = 2 · e + D} 2 When D _2, through The hole 61 always rotates in contact with the outer periphery of the contact portion 81.

Hereinafter, the operation of the external gear 5 of the eccentric oscillating speed reducer 1 will be described with reference to FIGS. 1 and 2.
As shown in FIG. 2, when the crankshaft 3 rotates around the rotation axis a, the external gear 5 revolves while meshing with an internal gear 21 provided on the inner peripheral surface of the housing 2. At this time, if the number of teeth of the external gear 5 is Z ₁ and the number of teeth of the internal gear 21 is Z ₂ , the external gear 5 rotates relative to the number of teeth of Z ₂ −Z ₁ per one rotation of the crankshaft 3. To do. That is, the external gear 5 performs one revolution revolution with the eccentricity e as a radius with respect to the housing 2 and a rotation (Z ₂ −Z ₁ ) / Z ₂ revolution. This rotation motion is transmitted to the rotating shaft 4 shown in FIG. 1 as an output shaft through the contact portions of the four through holes 51 and the four output pins 7.
Similarly, as shown in FIG. 3, the rotation of the external gear 6 is also an output shaft through the contact portions 81 of the four through holes 61 and the four output pins 8. Is transmitted to.

Hereinafter, the transmission torque in the case where the four output pins 7 are provided on the circumference equally will be described.
In FIG. 4, the external gear 5 meshes with the internal gear 21 at a point P, and an angle ∠QaP formed by the center Q of the output pin 7 a and the rotational axis a of the crankshaft 3 and the point P is 90 °. Here, when the transmission torque T ₁ in the external gear 5 act in clockwise, relative motion of the output pin 7c and the external gear 5 at the contact portion between the external gear 5 of the output pin 7c becomes away, the output pins Since the relative movement between the output pins 7b and 7d and the external gear 5 at the contact portions of the external gear 5 and 7b and 7d is tangential, no torque is transmitted.
The torque T ₁ transmitted to the rotating shaft 4 through the output pin 7a in the external gear 5 acts on the contact portion between the center of the output pin 7a and the rotating axis a R ₁ , and the output pin 7a and the through hole 51a. When the normal force to be performed is F ₁ , T ₁ = F ₁ · R ₁ .
Similarly, in the external gear 6, the torque T ₂ transmitted to the rotary shaft 4 via the output pin 8 is R ₂ , and the distance between the center of the output pin 8 and the rotary axis a is R ₂ . When the normal force acting on the contact portion is F ₂ , T ₂ = F ₂ · R ₂ .

Next, the relationship between the rigidity of the output pin 7 and the normal force will be described by replacing the distributed load at the contact portion with a concentrated load applied to one point for simplification.
In FIG. 5, the normal force F in the direction perpendicular to the axis of the output pin 7 is at the position of the contact portion between the through hole 51 of the external gear 5 and the output pin 7 whose distance from the press-fitting portion of the output pin 7 is L _{1 1} acts as a load, the rigidity of the load acting point and K _1, produces a displacement [delta] ₁ of the formula [delta] _{1 =} F 1 _/ K ₁ of the following load application point. That is, the normal force F ₁ = δ ₁ · K ₁ is generated as a reaction force by the displacement δ ₁ .
Here, the displacement δ ₁ is a circumferential displacement of a circle around the rotational axis a of the crankshaft 3 of the output pin 7, and the relative angular displacement of the external gear 5 and the rotational shaft 4 in the rotational direction is φ Then, δ ₁ = φ · R ₁ . Further, since the external gears 5 and 6 are meshed with the internal gear 21 and are simultaneously rotated by the crankshaft 3, the rotation speed is the same, so the relative angle of the external gears 5 and 6 and the rotation shaft 4 in the rotation direction. The displacement φ is the same.

Similarly, in FIG. 6, the position of the contact portion 81 of the through hole 61 and the output pin 8 of the external gear 6 Distance from the press-fitting portion of the L ₂ output pins 8, a direction perpendicular to the axis of the output pin 8 When the normal force F ₂ acts as a load and the rigidity of the load application point is K ₂ , the normal force F ₂ = δ ₂ · K ₂ is generated as a reaction force due to the displacement δ ₂ .

When the transmission torque _{T 1} of the external gear 5 is used the distance _{R 1} of the center and the rotation axis a of the stiffness _{K 1} and the relative angular displacement φ and the output pin 7 of the output pin _{7, T 1 = δ 1 ·} K 1 · R ₁ = φ · K ₁ · R ₁ ² When the transmission torque _{T 2} of the external gear 6 uses the distance _{R 2} of the center and the rotation axis a of the stiffness _{K 2} and the relative angular displacement φ and the output pin 8 of the output pin _{8, T 2 = δ 2 ·} K 2 · R ₂ = φ · K ₂ · R ₂ ²

In the above description, the case where the angle QaP formed by the center Q of the output pin 7a, the rotation axis a of the crankshaft 3, the external gears 5 and 6, and the meshing point P of the internal gear 21 is 90 ° will be described. However, in the case of other angles, a normal force corresponding to the angle acts on the two output pins. The sum of the two transmission torques based on this normal force is the same as described above, and T ₁ = φ · K ₁ · R ₁ ² and T ₂ = φ · K ₂ · R ₂ ² are other angles. It holds true.

Since the output pins 7 and 8 are cantilevered, most of the displacement between the contact portion between the output pins 7 and 8 and the external gears 5 and 6 and the shaft center portion of the rotary shaft 4 is the output pins 7 and 8. This is accounted for by the deflection displacement due to bending. Therefore, the stiffnesses K ₁ and K ₂ can be easily set to desired values by changing the bending stiffness of the output pins 7 and 8. It is known that the deflection displacement δt caused by bending is δt = F · L ³ / (3EI). Here, F is the load, L is the distance from the support point to the load application point, E is the longitudinal elastic modulus of the output pin, I is the cross-sectional secondary moment of the output pin, and the cross-sectional secondary moment I is the diameter of the output pin The longitudinal elastic modulus E is determined by the material. Even if L is constant, I and E can be changed by changing the diameter of the output pin and the material of the output pin. As a result, the stiffnesses K ₁ and K ₂ can be set to desired values.

Eccentrically oscillating speed reducer 1 in FIG. 1, for the transmission torque T ₂ of the transmission torque T ₁ and the external gear 6 of the external gear 5 on the same short output pins of the distance from the support point to the load action point 7, the diameter of the output pin 8 having a long distance from the support point to the load application point is increased to K ₁ = K ₂ and R ₁ = R _2, and K ₁ · R ₁ ² = K ₂ · R ₂ ² is an example.
In the eccentric oscillating speed reducer 1, since the external gears 5 and 6 have the same width, the allowable transmission torque of the external gears 5 and 6 is the same. Therefore, when the transmission torque is the same (C = 1), Allowable transmission torque is maximized and service life is extended. Since the diameter of the contact portion 81 of the output pin 8 circumscribing the through-hole 61 of the external gear 6 is made smaller than the diameter of the press-fit portion of the output pin 8 press-fitted and held on the rotary shaft 4, The thickness of the outer periphery can be increased, and the strength of the external gear 6 can be ensured.
Further, the diameter of the contact portion 81 of the output pin 8 may be the same as the diameter of the output pin 7. Since the external gear 5 and the external gear 6 can be made the same, the cost of the eccentric oscillating speed reducer is reduced.

An eccentric oscillating speed reducer 100 of the second embodiment is shown in FIG. The eccentric oscillating speed reducer 100 has the same diameter as that of the output pin 108 and the output pin 7 as the second output pin with respect to the eccentric oscillating speed reducer 1, and the distance R from the rotation axis a of the output pin 7. ₁ smaller, since the same configuration as the first embodiment except that a larger distance R ₂ from the axis of rotation a of the output pins 108 (FIG. 1), description thereof is omitted.
In the eccentric oscillating speed reducer 100, since the diameters of the output pins 7 and 108 are the same, K ₁ > K ₂ , and the relationship between R ₁ and R ₂ is the formula R ₁ ² = K ₂ · R ₂ ² / K _1. Is set to satisfy. Therefore, the eccentric oscillating type speed reducer 100, the transmission torque T ₂ of the transmission torque T ₁ and the external gear 6 of the external gear 5 are the same.
In the eccentric oscillating speed reducer 100, since the widths of the external gears 5 and 6 are equal, the allowable transmission torques of the external gears 5 and 6 are the same. Therefore, if the transmission torques are the same, the total allowable transmission torque is maximum. And the service life will be longer. Further, since the diameters of the output pins 7 and 108 are the same, the press-fitting holes of the output pins 7 and 108 of the rotary shaft 104 have the same dimensions and can be machined with the same tool. It is possible in the same process.

An eccentric oscillating speed reducer 200 of the third embodiment is shown in FIG. The eccentric oscillating speed reducer 200 has a width of the external gear 206 that is the second external gear smaller than that of the external gear 5 with respect to the eccentric oscillating speed reducer 1, and the housing 202 and the crank correspondingly. Since the configuration of the shaft 203 is the same as that of the first embodiment (FIG. 1) except that the axial dimension of the shaft 203 is reduced and the diameters of the output pin 208 and the output pin 7 as the second output pin are the same, the description is omitted. To do.
When the width of the external gear 5 of the eccentric rocking reduction gear 200 is C times larger than that of the external gear 206, the ratio of the allowable transmission torque of the external gear 5 to the allowable transmission torque of the external gear 206 is also C times. Further, since the diameters of the output pins 7 and 208 are the same, K ₁ > K ₂ , and the relationship between R ₁ and R ₂ satisfies the formula R ₁ ² = C · K ₂ · R ₂ ² / K _1. Is set. Therefore, the eccentric oscillating speed reducer 200, the ratio transmitted torque T ₂ of the external gear 206 of the transmission torque T ₁ of the external gear 5 is C times.
In the eccentric oscillating speed reducer 200, the ratio of the allowable transmission torque of the external gear 5 to the allowable transmission torque of the external gear 206 is C. Therefore, the transmission torque of the external gear 5 to the transmission torque of the external gear 206 is When the ratio is C, the total allowable transmission torque is maximized and the service life is extended. Further, since the diameters of the output pins 7 and 208 are the same, the press-fitting holes of the output pins 7 and 208 of the rotating shaft 204 have the same dimensions and can be machined with the same tool. It is possible in the same process. Furthermore, by using a combination of two types of external gears with different widths, three types of eccentric oscillating speed reducers can be manufactured. Therefore, the allowable transmission torque of the eccentric oscillating speed reducer while suppressing an increase in the number of parts. The number of types can be increased.

  In any of the eccentric oscillating speed reducers 1, 100, and 200, the output pin 7 is made of an iron alloy, and the output pins 8, 108, and 208 are made of a material having a large longitudinal elastic coefficient such as a cemented carbide. An increase in the diameter of the output pins 8, 108, 208 can be reduced. As a result, an increase in the outer diameter of the external gear can be reduced, and the outer diameters of the eccentric oscillating speed reducers 1, 100, 200 can be reduced.

  As described above, according to the present invention, the allowable transmission torque of the eccentric oscillating speed reducer that is thin with the output pin as a cantilever support is maximized, and the life is also increased. In addition, parts can be shared, and the cost of the eccentric oscillating speed reducer is reduced. Furthermore, by using a combination of two types of external gears with different widths, three types of eccentric oscillating speed reducers can be manufactured. Therefore, the allowable transmission torque of the eccentric oscillating speed reducer while suppressing an increase in the number of parts. The number of types can be increased.

  In each embodiment, the tooth shapes of the external gears 5, 6, 206 and the internal gear 21 are involute tooth shapes, but other tooth shapes such as a cycloid tooth shape may be used.

1: eccentrically oscillating speed reducer 3: crankshaft 5,6: external gear 7,8: Output Pin 21: internal gear 31: the cylindrical cam 51 and 61: through hole R _{1, R 2:} Output pin Distance from the center of the center internal gear

Claims (8)

Two eccentric cylinders in which the internal gear, the first and second external gears meshed with the internal gear, and the first and second external gears are arranged at different positions around the axis of the crankshaft. A crankshaft supported by a cam portion so as to be capable of revolving with respect to the central axis of the internal gear; and a plurality of output pins in contact with through holes parallel to the central axis of the internal gear provided in the first and second external gears; A rotary shaft that holds one end of the output pin and is rotatable with respect to a central axis of the internal gear, and rotates the crankshaft as an input shaft and either the internal gear or the rotary shaft as an output shaft. In the eccentric oscillating speed reducer,
The output pin comprises a first output pin that contacts only the through hole of the first external gear, and a second output pin that contacts only the through hole of the second external gear,
The desired value of the ratio of the transmission torque of the first external gear to the transmission torque of the second external gear is C, the first stiffness value that is the stiffness of the first output pin is K ₁ , and the second output pin The value of the second rigidity, which is the rigidity of the first output pin, is K ₂ , the distance from the center axis of the internal gear at the center of the first output pin is R ₁ , and the distance from the center axis of the internal gear at the center of the second output pin is R ₂ is set to satisfy the formula K ₁ · R ₁ ² = C · K ₂ · R ₂ ² ,
The first rigidity is a rigidity between a contact portion of the first output pin with the first external gear in a direction orthogonal to a central axis of the internal gear and an axial center portion of the rotation shaft, and the second An eccentric oscillating speed reducer having rigidity between the contact portion of the second output pin with the second external gear and the axial center portion of the rotary shaft in a direction perpendicular to the central axis of the internal gear. .   The distance from the support point of the second output pin to the contact point with the through hole of the second external gear is the contact point of the support point of the first output pin with the through hole of the first external gear. The eccentric oscillating speed reducer according to claim 1, wherein the second output pin has a diameter greater than that of the first output pin.   The eccentric oscillating speed reducer according to claim 2, wherein a diameter of a contact portion of the second output pin with the through hole of the second external gear is made smaller than a diameter of the holding portion by the rotating shaft.   The eccentric oscillating speed reducer according to claim 3, wherein the diameter of the contact portion of the second output pin with the through hole of the second external gear is the same as the diameter of the first output pin.   The eccentric oscillating speed reducer according to claim 1, wherein the first output pin and the second output pin have the same diameter. The distance from the support point of the second output pin to the contact point with the through hole of the second external gear is the contact point of the support point of the first output pin with the through hole of the first external gear. 6. The eccentric oscillating speed reducer according to claim ₁ , wherein the R ₂ is longer than the distance up to R _{1 and} is larger than the R ₁ .   The eccentric oscillating speed reducer according to any one of claims 1 to 6, wherein a width of the second external gear is made smaller than a width of the first external gear.   The eccentric oscillation speed reducer according to any one of claims 1 to 7, wherein a longitudinal elastic coefficient of a material of the first output pin is different from a longitudinal elastic coefficient of a material of the second output pin.

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