CN100451384C - Eccentric swing type planetary gear device - Google Patents

Abstract

The invention provides eccentric swing type planetary gear device, deformation of bridge sections in an externally toothed gear and of outer teeth is suppressed, and this extends the life of tooth surfaces of external teeth (19), improves vibration characteristics, and drastically increases output torque while preventing a planetary gear device (11) from becoming large in size. To achieve the above, a ratio obtained by dividing the diameter (D) of pins constructing internal teeth (14) by the pitch (P) of the internal teeth (14) is made smaller to an extent where the tooth tops (19a) of the external teeth (19) are radially outside the inner periphery (15a) of an internally toothed gear (15), or alternatively, a meeting point (C) where the lines (S) of action of reaction forces (K) as drive force components meet is moved more radially outward than a conventional position so as to be positioned between a pin circle (P) passing the centers of all the internal teeth (pins) (14) and an outer end passing circle (G) passing radially outer ends of through-holes (22), or further alternatively, the amount (H) of eccentricity of an externally toothed gear (18) relative to an internally toothed gear is set not less than 0.5 times the radius (R) of the internal teeth (pins)(14).

Description

Eccentric oscillating planetary gear unit

technical field

The present invention relates to an eccentric oscillating planetary gear device, which eccentrically oscillates an external gear meshed with an internal gear through a crankshaft.

Background technique

As a conventional eccentric oscillating planetary gear device, for example, a device described in Patent Document 1 is known.

The device is provided with: an internal gear with a plurality of cylindrical rollers arranged at a certain pitch on the inner circumference; an external gear with a plurality of crank shaft holes and through holes, and a trochoid on the outer circumference. The external teeth formed by the tooth shape mesh with the above-mentioned internal teeth and the number of teeth is only one less than the internal teeth; the crankshaft is inserted into each crankshaft hole, and the external gear is eccentrically oscillated by rotation; the support body can rotatably support the above-mentioned The crankshaft also has a plurality of cylinders movably inserted into the through holes.

And, in this device, as shown in FIG. 22 , the external teeth 02 of the externally toothed gears 01 that are in contact with each other respectively apply a drive in a direction perpendicular to the tooth surface to the internal teeth (rollers) 04 of the internal gear 03 at their contact points. At the same time, as its reaction, the internal teeth (rollers) 04 also apply the reaction force K of the above-mentioned driving component to the external teeth 02.

Moreover, as shown in FIG. 23 , the action lines S of the reaction force K of the driving component force applied by each external tooth 101 to the corresponding internal tooth (roller) 102 coincide on a converging point C, and this converging point C is located at, The outer end passing through the outer ends in the radial direction of all the through holes 103 passes through the circle G, and the inner end passing through the inner ends in the radial direction passes between the circle N.

Furthermore, such a planetary gear device is required to increase the output torque.

Here, the above-mentioned output torque is the total value of the product of the component force along the tangential direction of the driving force at each contact point of the external tooth and the internal tooth (roller), and the distance from the center of the internal gear to the above-mentioned contact point, However, according to the requirement of preventing enlargement, the distance from the center of the internal gear to the contact point is constant, so to increase the output torque, it can be considered to increase the component force of the drive component along the tangential direction. In addition, the increase of the component force of the drive component force along the tangential direction can move the above-mentioned line of action to the tangential direction side with respect to the external tooth gear by moving the convergent point where the lines of action of the drive component force overlap to the outside in the radial direction. Tilt to reach.

Patent Document 1: JP-A-7-299791

However, in the above-mentioned planetary gear device, due to the wall thickness of the bridge-like portion 06 on the radially outer side of the through hole 05 on the externally toothed gear 01 (from the radially outer end of the through hole 05 to the dedendum 07 of the external tooth 02 The radial distance between them is the minimum wall thickness) J is much smaller than the wall thickness of other parts, and the bending rigidity is low. Therefore, when the above-mentioned reaction force K generally acts on the bridge 06 in the radial direction, the bridge 06 and the bridge The outer teeth 02 near the shaped portion 06 are elastically deformed, and the outer teeth 02 come into contact with one end of the inner teeth (rollers) 04, which shortens the service life of the tooth surfaces of the outer teeth 02.

Moreover, if the bending rigidity of the bridge portion 06 is low as described above, when the above-mentioned planetary gear device is used in a robot, a machine tool, etc., when there is a torque load, the natural vibration frequency will be low, the vibration characteristics will deteriorate, and the controllability will be reduced. drop problem.

And, since this conventional eccentric oscillating planetary gear device, as mentioned above, the converging point C is located between the outer end passing circle G and the inner end passing circle N, so when the eccentric oscillating rotation of the external tooth gear 104 makes the above converging point When C is located near the center of the through hole 103 , the action line S of each reaction force K generally extends along the normal direction of the through hole 103 . Here, since the bridge portion 105 on the external gear 104 located on the radially outer side of the through hole 103 has a thinner wall thickness than other parts, the rigidity is low. The normal direction of 103 acts on the bridge 105 with low rigidity in a direction substantially perpendicular to the extending direction of the bridge 105, so that the bridge 105 and the external teeth 101 near the bridge 105 are elastic. Deformation causes the external teeth 101 to come into contact with one end of the internal teeth (rollers) 102, and there is a problem that the service life of the tooth surfaces of the external teeth 101 is shortened.

Furthermore, in order to prevent the tooth tops of the external teeth from interfering with the inner circumference of the internal gear, the externally toothed gear is obtained by dividing the position of the above-mentioned converging point (distance in the radial direction from the center of the internal gear) by the number of internal teeth (rollers). The amount of eccentricity relative to the internal gear must be less than 0.5 times the radius of the internal tooth (roller) (about 0.40 to 0.45 times in conventional planetary gear units). There is a limit to the outward movement, and there is a problem that the output torque cannot be sufficiently increased.

Contents of the invention

The object of the present invention is to provide an eccentric oscillating planetary gear device, which can prolong the tooth surface life of the external teeth by suppressing the elastic deformation of the bridge portion of the external tooth gear and the external teeth, and can also improve the vibration characteristics, and can prevent Increased output torque while upsizing.

The first method that can achieve such an object is to reduce the ratio of the diameter D of the rollers constituting the inner teeth divided by the fixed pitch P of the inner teeth to the ratio of the teeth of the outer teeth Interference between the external teeth and the inner circumference of the internal gear is avoided by cutting off at least the external teeth beyond the inner circumference of the internal gear in the radial direction outward of the inner circumference of the internal gear. The eccentric oscillating type planetary gear device has: an internally-toothed gear having a plurality of cylindrical rollers arranged at a constant pitch P on the inner periphery; and an externally-toothed gear formed with at least one crankshaft hole and a plurality of The through hole has an external tooth formed by a trochoidal tooth shape on the outer periphery, which meshes with the above-mentioned internal tooth and has only one less tooth than the internal tooth; the crankshaft is inserted into each crankshaft hole, and the external tooth gear is rotated by rotation. The eccentric swing; the supporting body rotatably supports the above-mentioned crankshaft, and has a plurality of columns inserted into the respective through holes.

The second method is to use the same eccentric oscillating planetary gear device to reduce the ratio of the diameter D of the rollers constituting the internal teeth divided by the fixed pitch P of the internal teeth so that the tooth tips of the external teeth exceed the inner circumference of the internal gear. At the same time, the inner circumference of the inner gear between adjacent inner teeth is cut off to a depth of more than the amount of the outer teeth exceeding the inner circumference, thereby avoiding interference between the outer teeth and the inner circumference of the inner gear.

The third way to achieve it is to make the converging point C where the action lines S of the reaction force K of the driving component force K applied by each external tooth to the corresponding internal tooth overlap in the following eccentric oscillating planetary gear device, located at the point passing through the inner tooth Between the roller circle P at the center of all the rollers and the outer end passage circle G passing through the radial outer ends of all the through holes. The eccentric oscillating planetary gear device has: an internally toothed gear with internal teeth formed by a plurality of cylindrical rollers arranged on the inner periphery; an externally toothed gear formed with at least one crankshaft hole and a plurality of through holes, and It has a plurality of external teeth formed by a trochoidal tooth shape and meshes with the above-mentioned internal teeth; the crankshaft is inserted into each crankshaft hole, and the external tooth gear is eccentrically oscillated by rotation; the support body can rotatably support the above-mentioned crankshaft , and has a plurality of columns inserted into each through hole.

The fourth method is to achieve the following eccentric oscillating type planetary gear device. When the eccentricity of the external gear with respect to the internal gear is H, and the radius of the roller constituting the internal teeth is R, the eccentricity H is within the range of 0.5 to 1.0 times the radius R, and each external tooth is cut off by a predetermined amount from the tooth top to avoid interference between the external tooth and the inner circumference of the internal gear. The eccentric oscillating planetary gear device has: internal teeth The gear has internal teeth formed by a plurality of cylindrical rollers on the inner circumference; the external tooth gear has at least one crankshaft hole and a plurality of through holes, and the outer circumference has a trochoidal tooth shape that is consistent with the above-mentioned inner teeth. The external teeth mesh with one tooth less than the internal teeth; the crank shaft is inserted into each crank shaft hole, and the external tooth gear is eccentrically oscillated by rotation; the support body can rotatably support the above crank shaft, and has a plurality of A columnar body inserted into each through hole.

The fifth method is to achieve the same eccentric oscillating type planetary gear device, when the eccentric amount of the external tooth gear relative to the internal gear is H, and the radius of the roller constituting the internal teeth is R, the above eccentric The amount H is within the range of 0.5 to 1.0 times the radius R, and the inner circumference of the internal gear between adjacent internal teeth is cut only to a predetermined depth, thereby avoiding interference between the external teeth and the inner circumference of the internal gear.

In the inventions pertaining to the above aspects 1 and 2, since the ratio of the diameter D of the roller constituting the internal teeth divided by the fixed pitch P of the internal teeth is reduced to such a degree that the addendum of the external teeth exceeds the radial direction outer side of the inner circumference of the internal gear Therefore, the diameter D of the above-mentioned internal teeth (rollers) is smaller than the conventional diameter, thereby, the dedendum of the external teeth of the external tooth gear moves outward in the radial direction, and as a result, the The wall thickness (minimum wall thickness) is thicker than before, and the bending rigidity is improved. As a result, the elastic deformation of the bridge portion and the external teeth can be suppressed when the reaction force of the driving component acts substantially in the radial direction, the service life of the tooth surface of the external teeth can be prolonged, and the natural vibration frequency can be increased, and the vibration characteristics and controllability can be improved. .

Here, in the configuration as described above, the external teeth interfere with the inner circumference of the internal gear, but in the invention according to aspect 1, at least the external teeth at a portion exceeding the inner circumference of the internal gear are removed, and in the invention according to aspect 2 The inner circumference of the internal gear between adjacent internal teeth is cut off only to a depth equal to or greater than the amount the external teeth exceed the inner circumference, thereby avoiding interference between the external teeth and the inner circumference of the internal gear.

Furthermore, according to the configuration of mode 3, the reduction of the transmission torque can be suppressed by leaving the inflection point which contributes the most to the transmission torque, and the noise and heat generation can be reduced by leaving the part where there is little slip between the external teeth and the internal teeth.

Furthermore, according to the configuration described in aspect 4, the Hertzian stress at the contact point between the internal teeth and the external teeth can be kept at a low value, and the tooth surface life of the external teeth can be further extended.

Furthermore, according to the configuration described in aspect 5, it is possible to prevent a sharp portion from being generated on the tooth surface, and it is also possible to increase the output torque.

In addition, if it is the configuration described in mode 6, since the action lines S of the reaction force K of the driving component force K applied by each external tooth to the corresponding internal tooth overlap, the converging point C is located outside the radial direction passing through all the through holes. The outer end of the end passes through the outside of the radial direction of the circle G, so when the converging point C is located on the radial direction line passing through the center of the through hole, the action line S of all the reaction forces K is inclined to the tangential direction side relative to the through hole than before, Close to the direction of extension of the bridge. As a result, elastic deformation of the thin and low-rigidity bridge portion and the external teeth in the vicinity of the bridge portion is suppressed, and the tooth surface life of the external teeth is extended.

Moreover, when the above-mentioned converging point C is located outside the radial direction of the outer end passing circle G as described above, since it is not the hollow part of the through hole but the bridge-shaped part with high rigidity in the tangential direction, the tangential direction of the above-mentioned respective reaction forces K is borne. force, and thus can suppress the deformation of the through hole. However, if the above-mentioned converging point C is located on the radially outer side of the roller circle P passing through the centers of all the rollers constituting the internal teeth, the above-mentioned converging point C must be located at the outer end passing Between circle G and roller circle P.

Here, when the above-mentioned converging point C is located between the roller circle P and the dedendum circle M, part of the reaction force K acts on the external tooth gear substantially in the tangential direction, and as a result, such reaction force K may cause the external teeth to bend and deform , However, if the convergence point C is located between the dedendum circle M and the outer end passing circle G as described in the mode 7, this situation can be prevented.

In addition, according to the configuration described in the eighth aspect, compared with the case where the difference in the number of teeth is 2 or more, a higher speed reduction ratio can be realized, and the processing cost can be reduced.

In the invention according to form 9, since the eccentricity H is set to be 0.5 times or more of the radius R, the radius between the center O of the internal gear and the converging point C can be obtained by multiplying the eccentricity H by the number of teeth Z of the internal teeth The directional distance L is larger than before, that is, the convergent point C can be greatly moved outward in the radial direction. As a result, the line of action S of the driving component force K' is greatly inclined to the tangential direction side with respect to the external tooth gear, and the tangential direction component force of the driving component force K' is increased. The output torque is increased with the number of meshing teeth.

Here, when the eccentricity H is set to be 0.5 times or more the radius R as described above, although the addendums of the external teeth interfere with the inner circumference of the internal gear, such a problem can be avoided by cutting each of the external teeth from the addendums by a predetermined amount. Interference between the external teeth and the inner circumference of the internal gear. On the other hand, in the invention according to claim 10 , the inner circumference of the internal gear between adjacent internal teeth is cut to a predetermined depth, thereby avoiding interference between the external teeth and the inner circumference of the internal gear. In addition, when the above-mentioned eccentricity H exceeds 1.0 times of the radius R, the eccentric swinging rotation of the external tooth gear in all the above cases will produce a rotational position where the external teeth and the internal teeth interfere, so the eccentricity H must be within the radius R 1.0 times or less.

In addition, according to the configuration described in aspect 11, it is possible to prevent a sharp portion from being generated on the tooth surface, and to significantly increase the output torque.

Furthermore, according to the configuration described in aspect 12, the bending rigidity of the external teeth can be improved, and the machining of the external teeth can be facilitated.

Description of drawings

Fig. 1 shows a side sectional view of Embodiment 1 of the present invention

Figure 2 I-I arrow sectional view of Figure 1

Figure 3 is an explanatory diagram showing the reaction force K acting on the external teeth and its line of action S

Figure 4 Enlarged view of the U part of Figure 3

Fig. 5 is a graph showing the relationship between the diameter D of the internal tooth (roller) and the Hertzian stress ratio

Fig. 6 is a graph showing the relationship between the value of L/R and the load ratio

Fig. 7 shows the same sectional view as Fig. 1 of Embodiment 2 of the present invention

Fig. 8 shows the same sectional view as Fig. 2 of Embodiment 2 of the present invention

Fig. 9 shows a side sectional view of Embodiment 3 of the present invention

Figure 10 Figure 9 II-II arrow sectional view

Fig. 11 is the same sectional view as Fig. 10 showing the meshing state of internal teeth and external teeth

Fig. 12 is an explanatory diagram illustrating a state where the action lines S of the driving component force (reaction force K) converge at the convergence point C

Figure 13 is a graph showing the relationship between load ratio and L/Q value

Fig. 14 shows a side sectional view of Embodiment 4 of the present invention

Figure 15 Figure 14 III-III cross-sectional view

Fig. 16 is the same sectional view as Fig. 15 showing the meshing state of internal teeth and external teeth

Fig. 17 is an explanatory diagram showing the driving component force K' acting on the internal teeth and its line of action S

Figure 18 is a graph showing the relationship between the L/Q value and the load ratio

Fig. 19 is a graph showing the relationship between the diameter D of the internal tooth (roller) and the Hertzian stress ratio

Fig. 20 shows the same sectional view as Fig. 14 of Embodiment 5 of the present invention

Fig. 21 shows the same sectional view as Fig. 15 of Embodiment 5 of the present invention

Fig. 22 is a cross-sectional view similar to Fig. 2 showing an example of the background art

FIG. 23 is an explanatory diagram illustrating a state where the action lines S of the drive component force (reaction force K) converge at the converging point C described in the background art.

Detailed ways

Embodiments of the present invention are described below.

Example 1

Embodiment 1 of the present invention will be described below with reference to the drawings.

In Fig. 1 and Fig. 2, 11 is an eccentric oscillating type planetary gear device for use in robots, etc., and this planetary gear device 11 has, for example, an approximately cylindrical rotating shaft attached to an arm or hand of a robot not shown in the figure. shell12. A plurality of roller (pin) grooves 13 having a semicircular cross-section at the central portion in the axial direction are formed on the inner periphery of the rotating housing 12. These roller grooves 13 extend in the axial direction and are separated at equal distances in the circumferential direction. It is arranged separately with a certain tooth pitch P. 14 is an internal tooth composed of a plurality of cylindrical rollers (the same number as the roller grooves 13), and approximately half of these internal teeth (rollers) 14 are inserted into the roller groove 13, so that Equidistant (certain tooth pitch P) is provided on the inner periphery of the rotating housing 12 .

Here, the above-mentioned constant pitch P is a value obtained by dividing the circumference of the roller circle V passing through the centers of all the rollers constituting the internal teeth 14 by the number of internal teeth (rollers) 14, in other words, by a circular arc line segment. The length of the arc connecting the centers of any two adjacent internal teeth (rollers) 14. The above-mentioned rotary housing 12 and internal teeth (rollers) 14 constitute an internal gear 15 in which internal teeth 14 composed of a plurality of cylindrical rollers are provided on an inner periphery 15a as a whole. As a result, the inner periphery 15 a of the internal gear 15 (rotary housing 12 ) is located on the above-mentioned roller circle V or at least near the roller circle V capable of holding the internal teeth (rollers) 14 .

Here, the number of internal teeth (rollers) 14 is about 25 to 100, preferably 30 to 80. The reason is that if the number of internal teeth (rollers) 14 is within the above range, the external gears 40, 42 described later are provided at the stage before the external gear 18 described later meshes with the internal gear 15. The spur gear reduction mechanism with a reduction ratio of 1/1 to 1/7 can easily obtain a high reduction ratio by combining the reduction ratios of the previous stage and the subsequent stage, and can also form a natural vibration frequency. High planetary gear with high reduction ratio.

The internal gear 15 accommodates a plurality of (here two) ring-shaped external gears 18 side by side along the axial direction. A plurality of external teeth 19 formed of a peritrochoid tooth shape. In addition, the number Z of the external teeth 19 of the externally toothed gear 18 is one less than the number Z of the internal teeth (rollers) 14 (the difference in the number of teeth is 1). The reason why the difference in the number of internal teeth (rollers) 14 and external teeth 19 is 1 is because the reduction ratio can be increased and the processing cost can be reduced compared with the case where the difference in the number of teeth is 2 or more.

Here, an external gear having a value G with a difference in the number of teeth of 2 or more is obtained by dividing the outer profile of the trochoidal external gear in the circumferential direction by the pitch of the external teeth 19 divided by the G value, and dividing these An externally toothed gear is taken out as a tooth profile in which G contour portions shifted in the circumferential direction overlap (see JP-A-3-181641). In addition, the external teeth 19 mesh with the internal teeth (rollers) 14 in a state where these external gears 18 and the internal gear 15 are inscribed, but the phases of the maximum meshing positions (deepest meshing positions) of the two external gears 18 are shifted. 180°.

Each externally toothed gear 18 is formed with at least one, here, three crankshaft holes 21 penetrating in the axial direction. equidistant. 22 is a plurality of (the same as the number of crank shaft holes 21, 3) through holes formed on each externally toothed gear 18, these through holes 22 are alternately arranged with the crank shaft holes 21 along the circumferential direction, and are spaced apart Open equidistant configuration. Then, the above-mentioned through hole 22 has a substantially pedestal shape in which the width in the circumferential direction becomes wider toward the radially outer side.

25 is a supporting body (support) that is embedded in the rotating housing 12 and installed on the fixed robot parts not shown in the figure. The end plates 26, 27, and one end are integrated with the end plate 26, and the other end is detachably connected to the end plate 27 by a plurality of bolts 28 (the same as the number of through holes 22, which is 3) columnar Body 29 constitutes. Moreover, the columnar body 29 connecting the above-mentioned end plates 26 and 27 extends along the axial direction, and is inserted (loosely fitted) into the through hole 22 of the external gear 18 with a certain gap.

Because the columnar body 29 is so loosely embedded in the through hole 22, the externally toothed gear 18 positioned at the radial direction outside of the through hole 22 constitutes an unsupported bridge portion 30 inside, and the wall thickness of the bridge portion 30 ( The radial distance from the radially outer end of the through hole 22 to the dedendum 19b of the external tooth 19 of the externally toothed gear 18 is the minimum wall thickness) J much smaller than the wall thickness of other parts, and the bending rigidity is low.

31 is a pair of bearings installed between the above-mentioned supporting body 25, specifically the outer peripheries of the end plates 26, 27 and the inner peripheries of both ends of the rotating housing 12 in the axial direction, and the supporting body 25 can rotatably support the internal teeth through these bearings 31. The gears 15.35 are at least one crankshaft (the same number as the crankshaft holes 21, 3) arranged at equal angles along the circumferential direction. These crankshafts 35 are externally embedded on one end of the axial direction The tapered roller bearing 36 and the tapered roller bearing 37 embedded in the other end in the axial direction can be rotatably supported by the support body 25, specifically the end plates 26 and 27.

The crankshaft 35 has two eccentric cams 38 equidistant from the central axis of the crankshaft 35 at the center in the axial direction, and the phases of these eccentric cams 38 are shifted by 180°. Here, the eccentric cams 38 of the above-mentioned crankshaft 35 are fitted in the crankshaft holes 21 of the externally toothed gear 18 respectively, and a needle roller bearing 39 is installed between them. As a result, the above-mentioned externally toothed gear 18 and the crankshaft 35 Relative rotation is allowed. Furthermore, external gears 40 are fixed to one axial end of each crankshaft 35, and these external gears 40 mesh with external gears 42 provided at one end of an output shaft 41 of a drive motor (not shown).

And, when the drive motor operates to rotate the externally toothed gear 40, the crankshaft 35 rotates around its central axis. The gear 18 eccentrically swings and rotates in the direction of the arrow. At this time, on the contact points of the intermeshing internal teeth (rollers) 14 and external teeth 19, as shown in Figures 2, 3 and 4, the external teeth 19 are applied to the corresponding internal teeth (rollers) 14 respectively. The drive component force along the action line S direction, and, as its reaction force, the reaction force K of the drive component force applied by the inner teeth (rollers) 14 to the outer teeth 19 along the action line S direction, respectively.

Here, the action lines S of the above-mentioned reaction forces K are located on a line perpendicular to the tooth surface where the above-mentioned contact point is located. Consisting of a trochoidal tooth shape, they converge (cross) at one point on the externally toothed gear 18 , that is, the converging point C. Then, the resultant force of the tangential direction component force of the above-mentioned driving component force acts on the internal gear 15 as a rotational driving force.

In addition, part of the reaction force K of the driving component force acts on the bridge portion 30 with low bending rigidity, and this reaction force K causes the bridge portion 30 and the external teeth 19 in the vicinity of the bridge portion 30 to elastically deform. If the external teeth 19 are in contact with one end of the internal teeth (roller) 14, the service life of the tooth surfaces of the external teeth 19 may be shortened, or the natural vibration frequency may be reduced, resulting in reduced vibration characteristics and controllability.

For this reason, in this embodiment 1, the ratio B of the diameter D of the roller constituting the internal teeth 14 divided by a certain pitch P of the internal teeth 14 is reduced so that the tooth crests 19a indicated by the imaginary lines of the external teeth 19 exceed the inner teeth 19a. The radial direction outer side of the inner periphery 15a of the gear 15, for example, when the number of teeth of the internal teeth (rollers) 14 is 40, it is about 0.55 in the past, and it is reduced to about 0.32, thereby making the above-mentioned internal teeth (rollers) The diameter D of ) 14 is smaller than conventional ones, and the dedendum 19 b of the external teeth 19 of the external tooth gear 18 is moved outward in the radial direction.

And, when the dedendum 19b of the external tooth 19 is moved radially outward as described above, the radial distance from the radially outer end of the through hole 22 to the dedendum 19b of the external tooth 19, that is, the wall of the bridge portion 30 The thickness J is thicker than before, and the bending rigidity is increased. As a result, the elastic deformation of the bridge portion 30 and the external teeth 19 is suppressed when the reaction force K is applied, and the tooth surface life of the external teeth 19 can be extended. It is also possible to increase the natural vibration frequency even in the case of low vibration, and to improve vibration characteristics and controllability.

Here, when the diameter D of the internal teeth (rollers) 14 is reduced as described above, both tooth surfaces come into contact with the adjacent internal teeth (rollers) 14 respectively (rotational front side tooth surfaces and rear side tooth surfaces) The tooth thickness and tooth height of the outer teeth 19 are increased, but if the ratio B is reduced so that the tooth top 19a exceeds the radial direction outside of the inner circumference 15a as described above, the outer teeth 19 with increased tooth heights interfere with the inner circumference 15a . For this reason, by cutting off at least the portion where the external teeth 19 exceed the inner circumference 15 a of the internal gear 15 , the interference of the external teeth 19 with the inner circumference 15 a of the internal gear 15 is avoided.

In this first embodiment, the maximum meshing position between the internal gear 15 and the external gear 18 is carried out so that only a slight gap is generated between the tips of the external teeth 19 after removal and the inner periphery 15a of the internal gear 15. Cut off, thereby avoiding the interference of the external teeth 19 with the inner periphery 15 a of the internal gear 15 . In addition, when the distance between the front side edge 44a in the rotation direction and the rear side edge 44b in the rotation direction of the external teeth 19 thus cut away is A, it is preferable to make the diameter D of the roller constituting the internal teeth 14 to be greater than the distance A Small.

Here, it is preferable to make the cutting position on the external teeth 19 of the above-mentioned externally toothed gear 18 the radius of the line M connecting the inflection points H of the two tooth surfaces of the external teeth 19 (the front tooth surface and the rear tooth surface in the rotation direction). Therefore, the diameter D of the rollers constituting the above-mentioned internal teeth 14 is the straight-line distance Y between the centers of two adjacent rollers constituting the internal teeth 14, minus the external teeth 19 cut along the connecting line M The difference in distance F between the front edge 45a in the rotation direction and the rear edge 45b in the rotation direction is greater than or equal to the difference. The reason is that, as described above, the inflection point H that contributes most to the transmission torque (the contact pressure with the internal teeth 14 is at a maximum value) can be kept without cutting off, and a decrease in the transmission torque can be suppressed. Here, the above-mentioned connecting line M is an arc line passing through the two inflection points H with the center axis of the externally toothed gear 18 as the center of curvature.

In addition, it is preferable that the cutting position of the external teeth 19 of the external tooth gear 18 is radially inward of the boundary N (the height position of 1/2 of the tooth height) between the addendum and the dedendum of the external teeth 19, thereby making the structure The diameter D of the roller of the internal tooth 14 is obtained by subtracting the distance E between the front edge 46a in the rotation direction and the rear edge 46b in the rotation direction of the external tooth 19 after cutting off the boundary N from the linear distance Y between the centers. Below the difference. The reason is that a large slip occurs when the external teeth 19 on the radially outer side of the boundary N mesh with the internal teeth (rollers) 14. Columns) 14 where the sliding is small, thereby reducing noise and heat generation.

Due to the above reasons, when the above-mentioned external teeth 19 are removed along the line M connecting the inflection points H of the two tooth surfaces, the distance between the front edge 45a in the rotation direction of the external teeth 19 and the rear edge 45b in the rotation direction is set to F, In addition, when the above-mentioned external tooth 19 is cut along the boundary N between the addendum and the dedendum, when the distance between the front edge 46a in the rotation direction and the rear edge 46b in the rotation direction of the external tooth 19 is E, it is preferably within the radius of the connecting line M The external teeth 19 are cut outside in the radial direction of the boundary N, so that the diameter D of the roller constituting the internal teeth 14 is equal to or greater than the difference between the straight-line distance Y between the centers minus the distance F, and less than the difference between the straight-line distance Y minus the distance E between the aforementioned centers.

Moreover, when the radius of the roller circle V is represented by R and the number of teeth of the external teeth 19 of the externally toothed gear 18 is represented by Z, it is preferable to make the diameter D of the rollers constituting the above-mentioned internal teeth 14 within 2R/Z±1.5mm. within range. The reason is that, when the diameter D is within the above range, as can be seen from the graph shown in FIG. A low value inside the point can prolong the tooth surface life of the external tooth 19 .

In addition, the graph shown in this FIG. 5 was calculated|required by performing simulation using the following each factor. That is, assuming that the number (number) of internal teeth (rollers) of each planetary gear device is 40, the radius R of the roller circle V is 120 mm, the number of external teeth is 39, and the ratio of the external gear 18 to the internal gear 15 is The eccentricity Q was a predetermined value of 2.7 mm, and the Hertzian stress at the contact point between the external teeth 19 and the internal teeth (rollers) 14 was obtained while changing the diameter D of the internal teeth (rollers) 14 . Here, FIG. 5 shows that the Hertzian stress value is exponent 1 when the diameter D is equal to 2R/Z.

Furthermore, as a method of moving the dedendum 19b of the external tooth 19 outward in the radial direction as the diameter D becomes smaller as described above, there is a method of keeping the eccentricity Q of the external gear 18 relative to the internal gear 15 constant, as follows: fixed value, increasing the diameter of the dedendum circles passing through all the dedendums 19b of the externally toothed gear 18; making the above-mentioned dedendum circles constant and constant, increasing the eccentricity Q; and increasing the dedendum at the same time However, in the first embodiment, the dedendum circle is kept constant and the eccentricity Q is increased.

When the eccentricity Q is increased in this way, the distance L from the center O of the internal gear 15 to the converging point C (which can be obtained by multiplying the eccentricity Q by the number of teeth of the internal teeth 14) is larger than before, that is, the converging point C can be made larger. The position moves outward in the radial direction, but at this time, it is preferable that the ratio of the distance L to the radius R of the roller circle V, that is, the value of L/R, be in the range of 0.86 to 1.00.

The reason is that if the value of L/R is set to 0.86 or more, the line of action S is inclined tangentially with respect to the externally toothed gear 18, and as a result, the wall thickness of the bridge-shaped portion 30 subjected to the above-mentioned reaction force K can be increased, effectively The elastic deformation generated by the bridge portion 30 is suppressed, and as can be seen from FIG. 6 , since the load ratio is substantially constant and the same torque is obtained, the load related to the transmitted torque acting on the external teeth 19 can be substantially constant. , and is the minimum value. However, when the value of the above-mentioned ratio L/R exceeds 1.00, sharp spots will be formed on the tooth surface when the external teeth 19 are produced, so the value of L/R is preferably 1.00 or less.

Here, the above-mentioned curve is obtained by simulation using the following factors. That is, assuming that the number of internal teeth (rollers) of each planetary gear device is 40, the diameter D of the rollers is 10 mm, the radius R of the roller circle V is 120 mm, and the number of external teeth is a fixed value of 39, The value of L/R is varied within the range of 0.5 to 1.0, and the component force in the tangential direction of the resultant force of the driving component force acting on the converging point C is obtained. Here, FIG. 6 shows a curve when the component load ratio in the above-mentioned tangential direction is an index of 1 when the value of L/R is 0.75.

In addition, if each external tooth 19 is cut off from the tooth top 19a by a predetermined amount as described above, the internal teeth (rollers) 14 and the external teeth 19 are only partially formed, and when the above-mentioned value of L/R is 1.0, only about 1/3 , Only about 3/4 meshes in the present embodiment 1, so the remaining about 1/4 internal teeth (rollers) 14 do not contact with the external teeth 19, and will come out of the roller groove 13. Therefore, in the present embodiment 1, as shown in FIG. 1, two insertion holes 49 formed with both ends of the internal teeth (rollers) 14 are inserted between the bearing 31 and the external tooth gear 18 as a control. The roller press ring 50 of the mechanism, and these two roller press rings 50 are fixed to the internal gear 15 in a non-rotatable manner, and the movement of the above-mentioned internal teeth (rollers) 14 is restricted.

In addition, as the above-mentioned control mechanism, it is also possible to use insertion holes formed on the inner end surface of the bearing outer ring of the bearing 31 into which the two ends of the above-mentioned internal teeth (roller) 14 are inserted, or the bearing outer ring of the bearing 31. A circumferential groove having the same width as the diameter of the internal tooth (roller) 14 is formed on the inner end surface.

Next, the operation of Embodiment 1 of the present invention will be described.

Now, the drive motor operates, and the crankshaft 35 rotates. At this time, the eccentric cam 38 of the crankshaft 35 rotates eccentrically in the crankshaft hole 21 of the externally toothed gear 18, causing the externally toothed gear 18 to swing and rotate eccentrically. ) 14 is only one less, so the rotating housing 12 and the robot arm etc. are rotated at a low speed due to the eccentric swinging rotation of the externally toothed gear 18.

Here, since the ratio B of dividing the diameter D of the internal teeth (rollers) 14 by a certain pitch P is reduced to as described above, the tooth tips 19a of the external teeth 19 exceed the radial direction outside of the inner circumference 15a of the internal gear 15 Therefore, the diameter D of the above-mentioned internal teeth (rollers) 14 is smaller than before, thereby, the dedendum 19b of the external teeth 19 of the external gear 18 moves outward in the radial direction, and as a result, the wall thickness J of the bridge portion 30 (minimum Wall thickness) is thicker than before, and the bending rigidity is enhanced.

Thus, the elastic deformation of the bridge portion 30 and the external teeth 19 under the reaction force K of the driving component is suppressed, the service life of the tooth surface of the external teeth 19 can be prolonged, and the natural vibration frequency is increased, which can improve vibration characteristics and controllability. Here, in the above configuration, the external teeth 19 interfere with the inner circumference 15a of the internal gear 15, but by cutting off at least the portion of the external teeth 19 that exceeds the inner circumference 15a of the internal gear 15, such interference between the external teeth 19 and the internal gear 15 is avoided. Interference of the inner periphery 15a of the internal gear 15.

Example 2

7 and 8 are diagrams showing Embodiment 2 of the present invention. In this second embodiment, the outer teeth 19 are not removed as in the first embodiment, but the inner circumference of the internal gear 15 (rotary casing 12) between adjacent internal teeth (rollers) 14 and the inner circumference of each The inner circumference around the inner teeth (roller) 14 is cut off to a depth greater than the amount by which the outer teeth 19 exceed the inner circumference. This avoids interference between the external teeth 19 and the inner periphery 15a of the internal gear 15 (rotary casing 12) after removal.

As a result, the radially outer end of each internal tooth (roller) 14 is in line contact with the inner periphery 15a of the internal gear 15 after removal, whereby the rotating housing 12 receives the driving force component acting on each internal tooth (roller) 14 The force component in the radial direction of . At this time, since there is no roller groove 13 , each internal tooth (roller) 14 can move freely, but the movement of the internal tooth (roller) 14 is restricted by the roller retainer 50 as described above. In addition, other structures and functions are the same as those of the first embodiment described above.

In addition, in the first embodiment described above, a plurality of (three) crankshaft holes 21 are formed in the externally toothed gear 18, and the crankshaft 35 rotating at a constant speed in the same direction is inserted into each crankshaft hole 21, so that the external teeth The gear 18 swings and rotates eccentrically. However, in the present invention, an eccentric cam of one crankshaft may be inserted into a crankshaft hole formed on the center shaft of the externally toothed gear 18, and the externally toothed gear may be rotated by the rotation of the crankshaft. Eccentric swing rotation. At this time, it is necessary for the columnar body of the support to be in contact with the inner circumference of the through hole.

Furthermore, in the first embodiment described above, the support body 25 is fixed and the internal gear 15 is rotated at a low speed, but in the present invention, the internal gear may be fixed and the support body is rotated at a low speed. Moreover, in the planetary gear device 11 of the original diameter without reducing the diameter D of the rollers constituting the internal teeth 14, the external teeth 19 can also be cut off at a position slightly outside the radial direction on the line M connecting the inflection point H, Suppresses reduction in transmitted torque while reducing heat generation and noise.

Example 3

Embodiment 3 of the present invention will be described below with reference to the drawings.

In Figs. 9, 10, and 11, 111 is an eccentric oscillating planetary gear device for use in robots, etc., and this planetary gear device 111 has a substantially cylindrical shape mounted on, for example, an arm, hand, etc. of a robot not shown in the figure. The housing 112 is rotated. A plurality of roller grooves 113 having a semicircular cross-section at the central portion in the axial direction are formed on the inner periphery of the rotary housing 112 , and the roller grooves 113 extend in the axial direction and are arranged at equal distances in the circumferential direction. 114 is an internal tooth composed of a plurality (the same number as the roller groove 113) of cylindrical rollers, and about half of these internal teeth (rollers) 114 are inserted into the roller groove 113, so they are spaced apart in the circumferential direction, etc. The distance is set on the inner circumference of the rotary housing 112 . The above-mentioned rotary housing 112 and internal teeth (rollers) 114 as a whole constitute an internal gear 115 in which internal teeth 114 composed of a plurality of cylindrical rollers are provided on the inner periphery. Here, about 25 to 100 internal teeth (rollers) 114 are arranged, but preferably within a range of 30 to 80 internal teeth (rollers). The reason is that if the number of internal teeth (rollers) 114 is within the above-mentioned range, and by assembling external gears 140, 142 described later, the necessary speed ratio can be easily obtained, and the natural vibration frequency can also be constituted. High planetary gear with high reduction ratio.

The internal gear 115 accommodates a plurality of (here two) ring-shaped external gears 118 side by side along the axial direction. A plurality of external teeth 119 formed in a scalloped shape. In addition, the number of teeth of the external teeth 119 of the externally toothed gear 118 is one less than the number of teeth of the internal teeth (rollers) 114 (the difference in the number of teeth is 1). The reason why the difference in the number of teeth between the internal teeth (rollers) 114 and the external teeth 119 is 1 is because compared with the value R where the difference in the number of teeth is 2 or more, a high reduction ratio can be easily achieved and the machining can be reduced. cost.

Here, the external tooth gear whose tooth number difference is a value R equal to or greater than 2 is an angle obtained by dividing the outer profile of the trochoidal external tooth gear by the pitch of the external teeth 119 in the circumferential direction by the R value, and dividing these An externally toothed gear is taken out as a tooth profile in which the overlapped R pieces of outer contour portions are shifted in direction (see JP-A-3-181641). In addition, the external teeth 119 mesh with the internal teeth (rollers) 114 in a state where the external gears 118 and the internal gear 115 are inscribed, but the phases of the maximum meshing portions (deepest meshing portions) of the two external gears 118 are shifted. 180°.

Each externally toothed gear 118 is formed with at least one, here, three crank shaft holes 121 penetrating in the axial direction. spaced an equal distance apart. 122 is a plurality of through holes (the same number as the crank shaft holes 121 ) formed on each externally toothed gear 118, and these through holes 122 are alternately arranged with the crank shaft holes 121 along the circumferential direction, and are spaced apart from each other by an equal distance in the circumferential direction. . Furthermore, the above-mentioned through hole 122 has a substantially pedestal shape in which the width in the circumferential direction becomes wider toward the outer side in the radial direction.

125 is a supporting body that is embedded in the rotating housing 112 and installed on the fixed robot parts not shown in the figure. , 127, and one end is integrated with the end plate 126, and the other end is made of a plurality of (the same as the number of through holes 122) columns 129 that can be detachably connected on the end plate 127 by a plurality of bolts 128. Moreover, the columnar body 129 connecting the above-mentioned end plates 126 , 127 extends along the axial direction, and is inserted (loosely fitted) into the through hole 122 of the external gear 118 with a certain gap.

131 is a bearing installed between the support body 125, specifically the outer circumference of the end plates 126, 127 and the inner circumference of both ends of the rotating housing 112 in the axial direction. The support body 125 can rotatably support the internal gear 115 through these bearings 131. 135 is at least one (the same as the number of crankshaft holes 121) crankshafts arranged at equal angles along the circumferential direction, and these crankshafts 135, through a tapered roller bearing 136 and The tapered roller bearing 137 fitted on the other end in the axial direction can be rotatably supported by the support body 125 , specifically the end plates 126 , 127 .

The crankshaft 135 has two eccentric cams 138 equidistant from the central axis of the crankshaft 135 at the center in the axial direction, and the phases of these eccentric cams 138 are shifted by 180°. Here, the eccentric cams 138 of the above-mentioned crankshaft 135 are fitted in the crankshaft hole 121 of the external gear 118 respectively, and a needle roller bearing 139 is installed between them. As a result, the above-mentioned external gear 118 and the crankshaft 135 Relative rotation is allowed. In addition, external gears 140 are fixed to one axial end of each crankshaft 135, and these external gears 140 mesh with external gears 142 provided on one end of an output shaft 141 of a drive motor (not shown).

And, when the drive motor operates to rotate the externally toothed gear 140, the crankshaft 135 rotates around its central axis. The gear 118 swings and rotates eccentrically. At this time, on the contact points of the intermeshing internal teeth (rollers) 114 and external teeth 119, the driving force components along the action line S direction applied by the external teeth 119 to the corresponding internal teeth (rollers) 114 act respectively. .

Here, the action lines S of the reaction forces K of the above-mentioned driving components are located on a line perpendicular to the tooth surface where the above-mentioned contact point is located as shown in FIG. The rollers) 114 have a cylindrical shape, and the external teeth 119 have a trochoidal tooth shape, so they converge (cross) at a point of convergence C on the external gear 118 . Then, the resultant force of the tangential direction components of the above-mentioned driving component forces acts on the internal gear 115 as a rotational driving force.

Here, if the converging point C is located between the outer end passing circle G and the inner end passing circle N (refer to FIG. 23 ), as explained in the above-mentioned background technology, due to part of the driving force component (near the maximum meshing position) The reaction force K acts on the bridge 105 with low rigidity in a direction substantially perpendicular to the extending direction of the bridge 105, so the bridge 105 and the external teeth 101 near the bridge 105 are elastically deformed, and the outer teeth 101 The tooth 101 is in contact with one end of the inner tooth (roller) 102, and the life of the tooth surface of the outer tooth 101 is shortened.

However, in this third embodiment, the above-mentioned converging point C is moved radially outward compared to the conventional one, and is positioned radially outside the above-mentioned outer end passing circle G. Therefore, when the converging point C is located on the radial line passing through the center of the through hole 122 as shown in FIG. The extending direction of the shaped portion 118a. As a result, elastic deformation of the thin and low-rigidity bridge portion 118 a and the external teeth 119 near the bridge portion 118 a is suppressed, and the tooth surface life of the external teeth 119 is prolonged.

Moreover, when the above-mentioned converging point C is located on the radially outer side of the outer end passing circle G as described above, the tangential line of the above-mentioned reaction force K is received by the bridge-like portion 118a with high rigidity in the tangential direction instead of the hollow portion of the through hole 122. The component force in the direction can suppress the deformation of the through hole 122 . However, when the above-mentioned converging point C is located on the radially outer side of the roller circle P passing through the centers of all the rollers constituting the internal teeth 114, sharp spots will be formed on the tooth surfaces of the external teeth 119. Therefore, the above-mentioned converging point C must be located at The outer end passes between the circle G and the roller circle P.

Here, due to the radial distance L from the center O of the internal gear 115 to the converging point C, the eccentricity H of the external gear 118 relative to the internal gear 115 can be multiplied by the internal teeth (rollers) 114 of the internal gear 115 In order to make the distance L larger than the conventional distance L shown in FIG. 23, one or both of the eccentricity H and the number of teeth can be made larger than before. Furthermore, although the eccentric amount H was increased in order to increase the distance L in the third embodiment, the outer diameter of the internal teeth (rollers) 114 is made smaller than conventional ones in order to further increase the eccentric amount H.

Here, it is preferable that the value of the ratio (L/Q) of the distance L in the radial direction to the radius Q of the roller circle P is within a range of 0.86 to 1.00. The reason is that if the value of the above-mentioned ratio L/Q is 0.86 or more, as shown in FIG. 13 , since the load ratio is substantially constant, the same torque can be obtained. Therefore, the transmission torque acting on the external teeth 119 can The relevant load (the tangential direction component of the drive component force) is substantially constant and the minimum value, but if it is less than 0.86, the change in the load ratio increases, and the load related to the transmission torque acting on the external teeth 119 increases. When the value of the ratio L/Q exceeds 1.00, sharp spots will be formed on the tooth surface when the external teeth 119 are generated.

Here, the above-mentioned curves are obtained by performing simulation under the following factors. That is, assuming that the number Z (number) of internal teeth (rollers) of each planetary gear unit is 40, the diameter of the internal teeth (rollers) is 10 mm, the radius Q of the roller circle P is 120 mm, and the number of external teeth is Set the value to 39, make the value of L/Q fluctuate in the range of 0.5 to 1.0, and obtain the component force in the tangential direction of the resultant force of the reaction force K acting on the convergent point C.

Here, FIG. 13 shows a curve when the load ratio of the above-mentioned tangential direction component force is exponent 1 when the value of L/Q is 0.75.

As described above, if the outer diameter of the internal teeth (rollers) 114 is made smaller than conventional ones, and the eccentricity H is made larger than conventional ones, the external teeth 119 whose both tooth surfaces are in contact with the internal teeth (rollers) 114 become larger. , that is, both tooth thickness and tooth height increase. However, since the inner periphery of the rotary housing 112 is generally located substantially on the above-mentioned roller circle P, if the external teeth 119 are enlarged, the external teeth 119 interfere with the inner periphery of the rotary housing 112 . Therefore, in this embodiment 3, only the tooth tops of the above-mentioned external teeth 119 (the positions indicated by imaginary lines in FIG. 11 ) are cut off by a predetermined amount along a circle whose center of curvature is the center of the external tooth gear 118, so as to prevent the external teeth 119 from colliding with the external teeth 119. The interference of the inner periphery of the rotating housing 112 . In addition, instead of cutting the tops of the outer teeth 119, the above-mentioned interference can be prevented by cutting the inner periphery of the rotary housing 112 between adjacent inner teeth (rollers) 114 to a predetermined depth.

Here, it is preferable that the above-mentioned converging point C be located between the dedendum circle M passing through the dedendums of all the external teeth 119 and the above-mentioned outer end passing circle G. The reason is that when the converging point C is located between the roller circle P and the dedendum circle M, part of the reaction force K acts on the external tooth gear 118 in a direction approximately tangential, and as a result, this reaction force K may make the outer tooth gear 118 The teeth 119 are bent and deformed; however, if the converging point C is located between the dedendum circle M and the outer end passing circle G as described above, this can be prevented.

And, if the tooth crest of each external tooth 119 is cut off as mentioned above, then the internal tooth (roller) 114 is only partly meshed with the external tooth 119, and only about 3/4 of it is meshed here, so the remaining approximately 1/4 of the internal tooth The teeth (rollers) 114 do not come into contact with the outer teeth 119 and come out of the roller grooves 113 . Therefore, in this third embodiment, insertion holes 131b into which both ends of the above-mentioned internal teeth (rollers) 114 are inserted are formed on the inner end surface of the bearing outer ring 131a of the above-mentioned bearing 131, thereby preventing the internal teeth (rollers) from 114 escapes from roller groove 113. And, at this time, the external teeth 119 transmit the driving force to the internal teeth (rollers) 114 within a range of about 3/8.

The above-mentioned insertion hole 131b as a whole constitutes a control mechanism 143 for preventing the internal teeth (rollers) 114 from falling out of the roller grooves 113 without contacting the external teeth 119 . In addition, as the above-mentioned control mechanism 143, instead of the insertion hole 131b, a circumferential groove formed on the inner end surface of the bearing outer ring 131a of the bearing 131 and having the same width as the diameter of the internal teeth (roller) 114 can be used; Between the two externally toothed gears 118, a roller press ring whose outer circumference contacts all the internal teeth (rollers) 114; and it is also possible to use a roller press ring arranged between the bearing 131 and the externally toothed gear 118 and formed with internal teeth (Roller) 114 Two roller retaining rings for inserting holes and circumferential grooves at both ends.

The function of Embodiment 3 of the present invention will be described below.

Now, the drive motor operates, and the crankshaft 135 rotates around its central axis in the same direction at the same speed. At this time, the eccentric cam 138 of the crankshaft 135 rotates eccentrically in the crankshaft hole 121 of the externally toothed gear 118, causing the externally toothed gear 118 to swing and rotate eccentrically. ) 114 has only one less tooth number, so the rotating housing 112 and the arm of the robot etc. rotate at a low speed due to the eccentric swinging rotation of the externally toothed gear 118 .

Here, since the line of action S of the driving component force (reaction force K) applied by each external tooth 119 of the external tooth gear 118 to the corresponding internal tooth (roller) 114 coincides, the converging point C is located through all the internal teeth. (Roller) Between the roller circle P at the center of the 114 and the outer end passing through the circle G passing through the radially outer ends of all the through holes 122, when the converging point C is located on the radial direction line passing through the center of the through hole 122, All the lines of action S of the reaction forces K are inclined tangentially to the through hole 122 , thereby suppressing elastic deformation of the bridge 118 a and the external teeth 119 near the bridge 118 a.

In addition, in the third embodiment described above, a plurality of (three) crankshaft holes 121 are formed on the externally toothed gear 118, and the crankshaft 135 rotating at a constant speed in the same direction is inserted into each crankshaft hole 121, so that the outer The toothed gear 118 swings and rotates eccentrically. However, in the present invention, one crankshaft may be inserted into a crankshaft hole formed on the center shaft of the externally toothed gear 118, and the externally toothed gear may be rotated eccentrically by the rotation of the crankshaft. . At this time, it is necessary for the columnar body of the support to be in contact with the inner circumference of the through hole.

Furthermore, in the third embodiment described above, the support body 125 is fixed and the internal gear 115 is rotated at a low speed, but in the present invention, the internal gear may be fixed and the support body is rotated at a low speed. Furthermore, in the present invention, a spur gear reduction mechanism with a reduction ratio smaller than 1/7 (approximately 1/1) may be provided in the previous stage of the above-mentioned planetary gear unit 111, and the reduction may be performed in two stages. In this way, a gear unit with a high reduction ratio and a high natural vibration frequency can be obtained.

Example 4

Embodiment 4 of the present invention will be described below with reference to the drawings.

In FIGS. 14, 15, and 16, 211 is an eccentric oscillating type planetary gear device for use in robots, etc., and this eccentric oscillating type planetary gear device 211 has an approximate cylinder mounted on, for example, a robot arm or hand not shown in the drawings. Shaped rotating housing 212 . A plurality of roller grooves 213 having a semicircular cross-section at the central portion in the axial direction are formed on the inner periphery of the rotary housing 212 , and the roller grooves 213 extend in the axial direction and are arranged equidistantly in the circumferential direction.

214 is an internal tooth composed of a plurality of cylindrical rollers (the same number as the roller groove 213). These internal teeth (rollers) 214 are approximately half inserted into the roller groove 213, thereby extending equidistantly along the circumferential direction. It is provided on the inner periphery of the rotating housing 212 . The above-mentioned rotary housing 212 and internal teeth (rollers) 214 as a whole constitute an internal gear 215 in which internal teeth 214 composed of a plurality of cylindrical rollers are provided on an inner periphery 215a. As a result, the inner periphery 215a of the internal gear 215 (rotary housing 212) is located on or very close to the roller circle P passing through the centers of all the rollers constituting the internal teeth 214. Here, about 25 to 100 internal teeth (rollers) 214 are arranged, but preferably within a range of 30 to 80. The reason is that if the number of internal teeth (rollers) 214 is within the above range, the speed reduction ratio is set to 1/1 to 1 by the stage before the meshing of the external gear 218 and the internal gear 215 described later. The /7 spur gear reduction mechanism can easily obtain a high reduction ratio by combining the reduction ratio of the previous stage and the subsequent stage, and can also constitute a planetary gear device with a high reduction ratio and a high natural vibration frequency.

The internal gear 215 accommodates a plurality of (here two) ring-shaped external gears 218 side by side along the axial direction. A plurality of external teeth 219 formed in a scalloped shape. In addition, the number of teeth of the external teeth 219 of the externally toothed gear 218 is one less than the number of teeth of the internal teeth (rollers) 214 (the difference in the number of teeth is 1). The reason why the difference in the number of internal teeth (rollers) 214 and external teeth 219 is 1 is because a higher speed reduction ratio can be achieved and the processing cost can be reduced compared to the value G where the difference in the number of teeth is 2 or more.

Here, the external tooth gear whose tooth number difference is a value G of 2 or more is such that the outer profile of the trochoidal external tooth gear is shifted in the circumferential direction by the distance of dividing the pitch of the external teeth 219 by the G value, and these are divided along the An externally toothed gear is taken out as a tooth profile in which G contour portions shifted in the circumferential direction overlap (see JP-A-3-181641). Furthermore, the external teeth 219 mesh with the internal teeth (rollers) 214 in a state where the external gears 218 and the internal gear 215 are inscribed, but the phases of the maximum meshing portions (deepest meshing portions) of the two external gears 218 are shifted. 180°.

Each externally toothed gear 218 is formed with at least one, here, three crank shaft holes 221 penetrating in the axial direction. spaced an equal distance apart. 222 is a plurality of through holes (the same number as the crankshaft holes 221 ) formed on each externally toothed gear 218, and these through holes 222 are alternately arranged with the crankshaft holes 221 along the circumferential direction, and are spaced at equal distances along the circumferential direction. . Furthermore, the above-mentioned through hole 222 has a substantially pedestal shape in which the width in the circumferential direction becomes wider toward the outer side in the radial direction.

225 is a supporting body (support) that is embedded in the rotating housing 212 and installed on the fixed robot parts not shown in the figure. The end plates 226, 227, and one end are integrated with the end plate 226, and the other end is detachably connected to the end plate 227 by a plurality of bolts 228 (the same as the number of through holes 222, which is 3) columnar Body 229 constitutes. Moreover, the columnar body 229 connecting the above-mentioned end plates 226 , 227 extends along the axial direction, and is inserted (loosely fitted) into the through hole 222 of the external gear 218 with a certain gap.

231 is a pair of bearings installed between the above-mentioned support body 225, specifically the outer circumference of the end plates 226, 227 and the inner circumference of both ends of the axis direction of the rotating housing 212, through these bearings 231 the support body 225 can rotatably support the internal teeth The gears 215 and 235 are at least one crankshaft (the same number as the crankshaft holes 221, 3) arranged at equal angles along the circumferential direction. The tapered roller bearing 236 and the tapered roller bearing 237 embedded in the other end in the axial direction are rotatably supported by the support body 225, specifically the end plates 226 and 227.

The crankshaft 235 has two eccentric cams 238 equidistant from the central axis of the crankshaft 235 at the center in the axial direction, and the phases of these eccentric cams 238 are shifted by 180°. Here, the eccentric cams 238 of the above-mentioned crankshaft 235 are fitted in the crankshaft hole 221 of the external gear 218 respectively, and a needle roller bearing 239 is installed between them. As a result, the above-mentioned external gear 218 and the crankshaft 235 Relative rotation is allowed. In addition, external gears 240 are fixed to one axial end of each crankshaft 235, and these external gears 240 mesh with external gears 242 provided on one end of an output shaft 241 of a drive motor (not shown).

And, when the drive motor works to rotate the externally toothed gear 240, the crankshaft 235 rotates around its central axis. 218 eccentric swing rotations. At this time, on the contact points of the internal teeth (rollers) 214 and the external teeth 219 that mesh with each other, as shown in FIG. The driving force component K' in the S direction.

Here, the action lines S of the above-mentioned driving component forces K' are located on a line perpendicular to the tooth surface where the above-mentioned contact point is located. The external teeth 219 have a trochoidal tooth shape, and thus converge (cross) at a point of convergence C that is one point on the external tooth gear 218 . Then, the output torque output from the internal gear 215 of such a planetary gear device 211 to the arm of the robot, etc. is the component of the drive component force K' at the contact points of the external teeth 219 and the internal teeth (rollers) 214 along the tangential direction. The force is the total of the product of the distance from the center O of the internal gear 215 to the above-mentioned contact point.

In addition, in this embodiment, in order to increase the above-mentioned output torque, the eccentricity H of the externally toothed gear 218 relative to the internal gear 215 is set to 0.5 times the radius R of the rollers constituting the internally toothed 214 beyond the conventional limit. above. If the eccentricity H is 0.5 times or more of the radius R, the radial distance L from the center O of the internal gear 215 to the converging point C (obtained by multiplying the eccentricity H by the number of teeth Z of the internal teeth (rollers) 214) is compared to It is conventionally large, that is, the position of the convergence point C can be largely moved outward in the radial direction.

As a result, the above-mentioned line of action S is inclined to the tangential direction side with respect to the externally toothed gear 218, and the tangential direction component of the driving component force K' is increased. , can increase the output torque. However, when the above-mentioned eccentricity H exceeds 1.0 times of the radius R, the position where the external teeth 219 interfere with the internal teeth (rollers) 214 occurs when the external tooth gear 218 eccentrically rotates, so the above-mentioned eccentricity H must be 0.5 times the radius R. times to 1.0 times.

In addition, assuming that the radial distance from the center O of the internal gear 215 to the converging point C (obtained by multiplying the eccentricity H by the number of teeth Z of the internal teeth (rollers) 214) is L as described above, it is assumed that the above-mentioned internal teeth 214 are formed by When the radius of the roller circle P at the center of all the rollers is Q, it is preferable that their ratio L/Q is in the range of 0.86 to 1.00.

The reason is that if the value of the above-mentioned ratio L/Q is 0.86 or more, as shown in FIG. 18 , since the load ratio is substantially constant, the same torque can be obtained. Therefore, the transmission torque acting on the external teeth 219 can The relevant load is generally constant and is the minimum value. If it is less than 0.86, the change in the load ratio will increase, and the load related to the transmission torque acting on the external teeth 219 will increase. When the value of the above ratio L/Q When the value exceeds 1.00, sharp spots will be formed on the tooth surface when the external teeth 219 are produced.

Here, the above-mentioned curve is obtained by simulation using the following factors. That is, assuming that the number Z (number) of internal teeth (rollers) of each planetary gear unit is 40, the diameter D of internal teeth (rollers) is 10 mm, the radius Q of the roller circle P is 120 mm, and the number of external teeth Let the constant value be 39, change the value of L/Q in the range of 0.5 to 1.0, and obtain the tangential direction component force of the resultant force of the driving component force K' acting on the converging point C. Here, FIG. 18 shows a curve when the load ratio of the above-mentioned tangential direction component force is exponent 1 when the value of L/Q is 0.75.

Also, when the value of L/Q is in the range of 0.86 to 1.00 as described above, the diameter D (radius R×2) of the internal teeth (roller) 214 is preferably within the diameter M (radius Q×2) of the roller circle P. 2) Except for the quotient of the number of teeth U of the outer teeth 219, that is, near the value of M/U, specifically within the range of M/U±2mm. The reason for this is that when the diameter D is near the value of M/U, the Hertzian stress that can be maintained at the contact point between the inner tooth (roller) 214 and the outer tooth 219 starts to increase rapidly as can be seen from the graph of FIG. 19 . A low value inside a large point can prolong the tooth surface life of the external teeth 219 .

In addition, in order to make the Hertzian stress a substantially constant minimum value, the diameter D is preferably within the range of M/U±0.75 mm as seen from FIG. 19 . In the curve shown in FIG. 19, except that the eccentricity H is 2.7 mm, the same conditions as the above-mentioned curve in FIG. The Hertzian stress at the point of contact with the internal tooth (roller) 14, the value of the Hertzian stress when the diameter D is equal to M/U is expressed as an index 1.

In addition, if the eccentricity H is set to 0.5 times or more the radius R as described above, the external teeth 219 in contact with the internal teeth (rollers) 214 on both tooth surfaces become larger, that is, the tooth thickness and tooth height are increased, Therefore, the external teeth 219 go beyond the inner circumference 215a of the internal gear 215 (rotary housing 12 ) located substantially on the roller circle P and enter, interfering with each other. Therefore, in this embodiment 4, the outer teeth 219 are cut off only a predetermined amount from the tooth top along the circle whose center of curvature is the center of the outer teeth gear 218 (only the part indicated by the dotted line in FIG. 16 ) to prevent the outer teeth from 219 interferes with the inner circumference 215a of the internal gear 215. In addition, it is preferable to cut off the amount of these external teeth 219 such that only a slight gap is generated between the top end of the cut external teeth 219 and the inner circumference 215a of the internal gear 215 at the maximum meshing position of the internal gear 215 and the external gear 218. degree of clearance.

In addition, as described above, when each external tooth 219 is partially cut off, when the distance between the front edge 219 a in the rotation direction and the rear edge 219 b in the rotation direction of one of the outer teeth 219 after removal is E, When F is the distance between the front edge 219 a in the rotation direction and the rear edge 219 b in the rotation direction of two adjacent external teeth 219 , it is preferable to make the distance E larger than the distance F . The reason is that, in this way, the bending rigidity of the external teeth 219 is increased, and the machining of the external teeth can be facilitated.

In addition, if each external tooth 219 is cut off by a predetermined amount from the top of the tooth as described above, since the internal teeth (rollers) 214 and the external teeth 219 are only partially meshed, the above-mentioned value of L/Q is about 1/3 when the value of L/Q is 1.0. In Embodiment 4, about 3/4 meshes, so the remaining about 1/4 internal teeth (rollers) 214 are not in contact with the external teeth 219 and will come out of the roller grooves 213 . Therefore, in Embodiment 4, insertion holes 231b into which both ends of the above-mentioned internal teeth (rollers) 214 are inserted are formed on the inner end surface of the bearing outer ring 231a of the above-mentioned bearing 231, thereby preventing the internal teeth (rollers) from Column) 214 escapes from the roller groove 213. And, at this time, the external teeth 219 transmit the driving force to the internal teeth (rollers) 214 within a range of about 3/8.

The above-mentioned insertion hole 231 b as a whole constitutes a control mechanism 243 that prevents the internal teeth (rollers) 214 from falling out of the roller grooves 213 without contacting the external teeth 219 . In addition, as the above-mentioned control mechanism 243, instead of the insertion hole 231b, a circumferential groove formed on the inner end surface of the bearing outer ring 231a and having the same width as the diameter of the internal teeth (roller) 214 may be used, or a circumferential groove arranged between the above two teeth (roller) 214 may be used. One roller press ring that is in contact with all the internal teeth (rollers) 214 on the outer periphery between the external teeth gears 218 .

The function of Embodiment 4 of the present invention will be described below.

Now, the drive motor operates, and the crankshaft 235 rotates around its central axis in the same direction at the same speed. At this time, the eccentric cam 238 of the crankshaft 235 rotates eccentrically in the crankshaft hole 221 of the externally toothed gear 218, causing the externally toothed gear 218 to swing and rotate eccentrically. ) 214 has only one less tooth number, so the rotating case 212 and the arm of the robot etc. rotate at a low speed due to the eccentric swinging rotation of the externally toothed gear 218 .

Here, since the eccentricity H is set to be 0.5 times or more the radius R as described above, the distance L from the center O of the internal gear 15 to the converging point C is larger than before, that is, the position of the converging point C can be made radially outward. As a result, the line of action S is inclined to the tangential direction side larger than before with respect to the externally toothed gear 218, and the tangential direction component of the drive component force K' increases, thereby increasing the output torque.

Example 5

20 and 21 are diagrams showing Embodiment 5 of the present invention. In this fifth embodiment, the outer teeth 219 are not removed as in the fourth embodiment, but the inner circumference 215a and The inner circumference 215a around each internal tooth (roller) 214 is cut off to a predetermined depth, here, the depth is substantially equal to the radius R of the internal tooth (roller) 214, so as to avoid the external teeth 219 from colliding with the internal gear 215. The interference of the inner periphery 215a of (the rotating housing 212). Here, the cutting amount of the inner circumference 215a can be appropriately determined according to the above-mentioned penetration amount of the outer teeth 219 .

As a result, the radially outer end of each internal tooth (roller) 214 is in line contact with the inner periphery 215a of the cut internal gear 215, whereby the rotating housing 212 receives the driving force component acting on each internal tooth (roller) 214. The radial direction component of K'. At this time, since the roller groove 213 does not exist, each internal tooth (roller) 214 can move freely. Therefore, in this fifth embodiment, two roller press rings as a control mechanism are installed between the bearing 231 and the externally toothed gear 218. 246, and the two roller pressure rings 246 are non-rotatably fixed on the internal gear 215 to limit the movement of the above-mentioned internal teeth (rollers) 214. In addition, other configurations and functions are the same as those of the fourth embodiment described above.

In addition, in the above-mentioned Embodiment 4, a plurality of (three) crankshaft holes 221 are formed in the externally toothed gear 218, and the crankshaft 235 rotating at a constant speed in the same direction is inserted into each crankshaft hole 221, so that the outer The toothed gear 218 swings and rotates eccentrically. However, in the present invention, one crankshaft may be inserted into a crankshaft hole formed on the center shaft of the externally toothed gear 218, and the externally toothed gear may be rotated eccentrically by the rotation of the crankshaft. . At this time, it is necessary for the columnar body of the support to be in contact with the inner circumference of the through hole.

Furthermore, in the above-mentioned fourth embodiment, the support body 225 is fixed and the internal gear 215 is rotated at a low speed, but in the present invention, the internal gear may be fixed and the support body is rotated at a low speed. Furthermore, in the present invention, a spur gear reduction mechanism with a reduction ratio smaller than 1/7 (approximately 1/1) may be provided in the preceding stage of the above-mentioned planetary gear unit 211, and the reduction may be performed in two stages. In this way, a gear unit with a high reduction ratio and a high natural vibration frequency can be obtained. In addition, in the above-mentioned fourth embodiment, only the external teeth 219 are removed by a predetermined amount from the tooth tips, and in the fifth embodiment, the inner circumference 215a of the internal gear 215 (rotary housing 212 ) between the internal teeth (rollers) 214 is cut Only a predetermined depth is cut off, but the present invention can also cut off the inner circumference of the external teeth and the internal gear at the same time.

Industrial Utilization Possibility

The present invention can be used in an eccentrically oscillating planetary gear unit in which an externally toothed gear meshing with an internal gear is eccentrically oscillated by a crankshaft.

Explanation of symbols

11, 111, 211... planetary gear unit

14, 114, 214...Internal teeth (roller)

15, 115, 215...internal gear

15a...inner circumference

18, 118, 218...external teeth gear

19, 119, 219...External teeth

21, 121, 221...crank shaft hole

22, 122, 222...through hole

25, 125, 225...support body

29, 129, 229... column

35, 135, 235... crankshaft

45a...front edge in direction of rotation

45b...Rear side edge in direction of rotation

46a...front edge in direction of rotation

46b...Rear side edge in direction of rotation

P...Roller circle

G... the outer end passes through the circle

M...Root circle

C...convergence point

S...line of action

K...reaction force of drive component

H...Eccentricity

K′...Drive component

R...Roller radius

Q...Roller circle radius

E...distance

F...distance

Claims (5)

1. eccentric oscillating-type planetary gear device, have: internal-gear is provided with the internal tooth that is made of a plurality of cylindric rollers at interior Zhou Yiyi constant pitch P; External tooth gear is formed with at least one crank axis hole and a plurality of through hole, have on the periphery constitute by the trochoid profile of tooth, with the external tooth of few 1 of the engagement of above-mentioned internal tooth and this internal tooth of gear ratio; Crankshaft inserts in each crank axis hole, makes the external tooth gear eccentric swing by rotation; Supporting body can be supported above-mentioned crankshaft rotatably, and has a plurality of Cylindrical objects that are inserted in each through hole; It is characterized in that:

The tooth top that the diameter D that makes the roller that constitutes internal tooth is decreased to external tooth divided by the ratio of a constant pitch P of internal tooth surpasses the interior week of internal-gear to the radial direction outside, and excision is avoided the interference in the interior week of external tooth and internal-gear thus above the external tooth at the position in the interior week of internal gear at least.

2. eccentric oscillating-type planetary gear device, have: internal-gear is provided with the internal tooth that is made of a plurality of cylindric rollers at interior Zhou Yiyi constant pitch P; External tooth gear is formed with at least one crank axis hole and a plurality of through hole, have on the periphery constitute by the trochoid profile of tooth, with the external tooth of few 1 of the engagement of above-mentioned internal tooth and this internal tooth of gear ratio; Crankshaft inserts in each crank axis hole, makes the external tooth gear eccentric swing by rotation; Supporting body can be supported above-mentioned crankshaft rotatably, and has a plurality of Cylindrical objects that are inserted in each through hole; It is characterized in that:

The tooth top that the diameter D that makes the roller that constitutes internal tooth is decreased to external tooth divided by the ratio of a constant pitch P of internal tooth surpasses the interior week of internal-gear to the radial direction outside, and the interior week excision aforementioned external teeth of the internal-gear between the adjacent internal tooth surpassed the above degree of depth of amount in interior week, avoid the interference in the interior week of external tooth and internal-gear thus.

3. eccentric oscillating-type planetary gear device as claimed in claim 1, when being made as F along the sense of rotation forward edge of the external tooth after the excision of the line M between the flex point H of the sense of rotation front side flank of tooth of aforementioned external teeth and the rear side flank of tooth aforementioned external teeth and the distance between the sense of rotation posterior edges, and will be when the sense of rotation forward edge of the external tooth after the boundary N excision aforementioned external teeth of the tooth top of aforementioned external teeth and tooth root and the distance between the sense of rotation posterior edges be made as E, by than line M near the radial direction outside and than boundary N near the inboard place's excision of radial direction aforementioned external teeth, make the diameter D of the roller that constitutes above-mentioned internal tooth, more than the crow flight distance Y between the center of the adjacent roller that constitutes internal tooth deducts difference apart from F, and below the crow flight distance Y between the above-mentioned center deducts difference apart from E.

4. eccentric oscillating-type planetary gear device as claimed in claim 1 or 2, when the radius of the roller circle V at the center of all rollers that will be by constituting above-mentioned internal tooth is made as R, and when the number of teeth of the external tooth of external tooth gear was made as Z, the diameter D that makes the roller that constitutes above-mentioned internal tooth was in the scope of 2R/Z ± 1.5mm.

5. eccentric oscillating-type planetary gear device as claimed in claim 1 or 2, when the radius of the roller circle V at the center of all rollers that will be by constituting above-mentioned internal tooth is made as R, and when the radial direction distance till the convergent point C that the line of action S of reaction force K that will impose on the driving component of corresponding internal tooth from the center O of above-mentioned internal-gear to external tooth overlaps is made as L, make above-mentioned radial direction distance L in 0.86～1.00 times scope of above-mentioned radius R.

Images