Rocking type reduction gear

Abstract

The present invention provides a rocking type reduction gear, which is a reduction gear having a large crossing angle and can be further miniaturized compared with the prior reduction gear. The rocking type reduction gear 1 includes: a main body 10, an input shaft 20 rotatably held by the main body 10, a precession body 30 performing precession motion, a rocking body 40 engaged with the precession body 30 and rocking through precession motion, and an output shaft 50 rotated by the rocking of the rocking body 40. In the present invention, a precession motion annular groove 34 for the precession motion of the precession body 30 and a rocking annular groove 33 for the rocking of the rocking body 40 are provided on the surface of the spherical portion 31. Thus, compared with the case where these grooves are provided on the inner circumferential surface of the member in the prior art, the area where groove machining can be performed can be increased, and the device can be further miniaturized.

Description

Technical Field

[0001] The present invention relates to a reduction gear that, for example, reduces the drive of an input shaft and transmits rotation to an output shaft. In particular, the present invention relates to a rocking type reduction gear that can increase the crossing angle between the input shaft and the output shaft, eliminate the offset volume of the drive mechanism part in a robot arm or the like, and achieve compactness, thereby achieving a rocking type reduction gear similar to the joint drive of humans, animals, etc. Background Art

[0002] As general orthogonal reduction gears, there are gear mechanisms such as bevel gears, hyperboloidal gears, worms, and worm gears. In addition, as these reduction gears, there are those that perform reduction with a single mechanism and those that are combined with a general coaxial rocking type reduction mechanism. These reduction gears are used in many fields, represented by the joint parts of robots.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent Publication No. 3790715

[0006] Patent Document 2: Japanese Patent Publication No. 3711338 Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] Among them, as a reduction gear having a right angle or a crossing angle with intersecting axes, a reduction gear having a bevel gear mechanism can be cited. However, in the case of using a gear mechanism, backlash between the gears is inevitably generated, resulting in a reduction in driving accuracy and the generation of noise.

[0009] In addition, in these gear mechanisms, reduction is performed by the gear ratio between the input side and the output side. Therefore, in order to obtain a large reduction ratio, gears with a large gear ratio are required, and a large space is needed. Moreover, since the gear meshing is performed at a position far from the axis, the number of teeth meshing simultaneously is also small. In addition, there are problems such as a reduction in rotational accuracy or positioning accuracy due to the influence of meshing tolerance or shaft deflection, and noise is likely to be generated during rotation.

[0010] The inventors of the present case proposed a device, which is a rocking type reduction gear with a right angle or a large crossing angle. As shown in Patent Document 1 and Patent Document 2, the input rotation is converted into precession motion via a spherical precession body (the rocking body in each document), and then into the rotational motion of an output shaft with orthogonal axes through an output rocking body that rocks by engaging with a part of the surface of the spherical portion of the precession body.

[0011] In these rocking type reduction gears, since the backlash can be made to approach zero and a relatively large reduction ratio can be achieved structurally, the overall size of the device can be made smaller compared to bevel gear mechanisms and the like.

[0012] In the rocking type reduction gears of these Patent Document 1 and Patent Document 2, it is possible to miniaturize bevel gear mechanisms and the like. However, in recent years, in robot arms and the like, a smaller joint mechanism is desired.

[0013] The inventors of the present case intended to fabricate an original device that is smaller than the previous rocking type reduction gear. However, it was found that in the previous mechanism, it was difficult to form a circulation groove for the orbit that drives the precession body and the output rocking body to rotate the necessary spherical members.

[0014] An object of the present invention is to provide a rocking type reduction gear that has a large crossing angle and can be further miniaturized compared to the previous reduction gears.

[0015] Means for Solving the Problem

[0016] To achieve the above object, the rocking type reduction gear of the present invention is composed of the following members in the X - Y - Z coordinate system:

[0017] An input shaft, which is rotatably supported by the main body around an input axis extending in the X - axis direction.

[0018] A precession body, which has a spherical portion and a pair of precession shaft portions. The pair of precession shaft portions project from both sides along a precession axis passing through the center of the spherical portion. One of the precession shaft portions is held by the input shaft in a manner that allows precession around the X - axis.

[0019] A precession motion support body, which supports the precession body relative to the main body in a manner that allows precession motion and is fixed to the main body.

[0020] A rocking body, which engages with the surface of the precession body on the side opposite to the precession motion support body side in the Z - axis direction and rocks through the precession motion of the precession body.

[0021] A rocking support that engages with the aforementioned rocking body and supports the rocking of the aforementioned rocking body relative to the aforementioned main body; and

[0022] An output shaft that is rotatably supported by the aforementioned main body about the Z-axis direction, engages with the aforementioned rocking body, and rotates by the rocking of the aforementioned rocking body;

[0023] On the surface of the aforementioned precession motion body on the side of the precession motion support, a precession motion annular groove is provided. The precession motion annular groove is formed by setting the trajectory depicted between the aforementioned precession motion body and the aforementioned precession motion support as a groove during the precession motion of the aforementioned precession motion body. A precession motion sphere that rotates in the aforementioned precession motion annular groove is rotatably held by the aforementioned precession motion support;

[0024] On the surface of the aforementioned precession motion body on the side of the aforementioned rocking body, a rocking annular groove is provided. The rocking annular groove causes the aforementioned rocking body to rock in the circumferential direction and the Z-axis direction about the Z-axis during the precession motion of the aforementioned precession motion body. A rocking sphere that rotates in the aforementioned rocking annular groove is rotatably held on the surface of the aforementioned precession motion body on the side of the aforementioned rocking body;

[0025] On the surface of the aforementioned rocking body on the side of the aforementioned rocking support, a rocking guide groove is provided. The rocking guide groove guides the rocking motion of the aforementioned rocking body. A rocking guide sphere that rotates in the aforementioned rocking guide groove is rotatably held by the aforementioned rocking support;

[0026] On the surface of the aforementioned rocking body on the side of the aforementioned output shaft, a wavy groove is provided over the entire circumference. The wavy groove is formed by a plurality of continuous arc-shaped grooves with an amount corresponding to one cycle of the rocking of the aforementioned rocking body. An output sphere that rotates in the aforementioned wavy groove is rotatably held by the aforementioned output shaft.

[0027] The rocking type reduction gear of the present invention causes the precession motion body to perform precession motion by the rotation of the input shaft, converts the precession motion of the precession motion body into the rocking of the rocking body, and converts the rocking of the rocking body into the rotational motion of the output shaft through the wavy groove and the output sphere. According to this structure, by one rotation of the input shaft, the precession motion body performs one cycle of precession motion, and through this one cycle of precession motion, the rocking body performs one cycle of rocking, and further through this one cycle of rocking, the output shaft rotates only by an amount corresponding to one cycle of arc-shaped grooves, so that a large reduction ratio can be easily obtained.

[0028] In addition, in the rocking reduction gear of the present invention, for smooth operation, precise groove machining of the precession motion annular groove, the rocking annular groove, and the wavy groove is required. In the present invention, the precession motion annular groove and the rocking annular groove are provided on the surface of the spherical precession motion body, and the wavy groove is provided on the surface of the rocking body. In the past, it was difficult to machine these grooves on the inner peripheral surface of the member, and further miniaturization was difficult. In the present invention, compared with such prior devices, groove machining becomes easier, and compared with the prior art, a rocking reduction gear that can be further miniaturized can be realized.

[0029] Furthermore, in the rocking reduction gear of the present invention, the precession motion support body may also include a precession energizing unit. The precession energizing unit is mounted to the main body via an elastic member and energizes the precession motion sphere toward the precession motion annular groove. According to this structure, when the precession motion body performs precession motion, since the precession motion support body energizes the precession motion body through the precession energizing unit, smooth precession motion can be performed.

[0030] In addition, in this structure, the precession motion support body may also be oriented toward the center of the spherical portion and energize the precession motion sphere toward the precession motion annular groove. With this structure, when a load is applied to the precession motion sphere, the load can be evenly distributed.

[0031] Moreover, in the rocking reduction gear of the present invention, the rocking support body may also include a rocking energizing unit. The rocking energizing unit is mounted to the main body via an elastic member and energizes the rocking guide sphere toward the rocking guide groove. According to this structure, when the rocking body rocks, since the rocking support body has a rocking energizing unit that energizes the rocking guide sphere toward the rocking guide groove, smooth rocking can be performed.

[0032] Effects of the Invention

[0033] According to the present invention, a rocking reduction gear can be provided, which is a reduction gear having a large crossing angle and can be further miniaturized compared with prior reduction gears. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 FIG. 1 is a partial cross-sectional view showing the rocking reduction gear of the present embodiment.

[0035] FIG. 2(A) is Figure 1 an exploded view of the rocking reduction gear, and FIG. 2(B) is an enlarged cross-sectional view taken along line B-B of FIG. 2(A).

[0036] Fig. 3(A) is an explanatory diagram showing the rocking annular groove on the upper surface side of the spherical portion of the precession body, and Fig. 3(B) is an explanatory diagram showing the precession motion annular groove on the lower surface side of the spherical portion.

[0037] Figure 4 It is an exploded view of the components above the precession body in the rocking type reduction gear located at Figure 1 .

[0038] Figures 5(A) to 5(C) It is an explanatory diagram showing the structure of the rocking body of this embodiment.

[0039] Figure 6 It is a cross-sectional view for explaining the structure of the precession motion annular groove of the precession body.

[0040] Figure 7 It is an explanatory diagram showing the relationship between the precession motion annular groove on the lower surface side of the spherical portion and the precession motion sphere.

[0041] Figure 8 It is an explanatory diagram showing the relationship between the rocking annular groove on the upper surface side of the spherical portion and the rocking sphere.

[0042] Figure 9 It is an explanatory diagram showing the relationship between the wavy groove on the upper surface of the rocking portion and the output sphere.

[0043] Figure 10 It is an explanatory diagram showing a modified example of the precession motion support body.

[0044] Symbol Explanation

[0045] 1, 1a: Rocking type reduction gear

[0046] 10, 10a: Body

[0047] 11: Front plate

[0048] 12: Rear plate

[0049] 13, 13b: Bottom plate

[0050] 14: Top plate

[0051] 15: Input bearing

[0052] 16: Precession motion support body

[0053] 16a: Recess

[0054] 16b: Precession motion sphere

[0055] 16d: Leaf spring

[0056] 17: Rocking support body

[0057] 17b: Shaking guide sphere

[0058] 17c: Fixed member

[0059] 17d: Leaf spring

[0060] 20: Input shaft

[0061] 20A: Input axis center

[0062] 21: Shaft portion

[0063] 22: Centrifugal portion

[0064] 23: Precession bearing

[0065] 24: Centrifugal bearing

[0066] 30: Precession body

[0067] 30A: Precession axis center

[0068] 31: Spherical portion

[0069] 31c: Center

[0070] 32: Precession shaft portion

[0071] 33: Shaking annular groove

[0072] 34: Precession movement annular groove

[0073] 40: Shaking body

[0074] 40A: Shaking axis center

[0075] 40a: Concave portion

[0076] 40b: Shaking sphere

[0077] 41: Support portion

[0078] 41a: Shaking guide groove

[0079] 42: Guide portion

[0080] 42a: Wavy groove

[0081] 42b: Arc-shaped groove

[0082] 50: Output shaft

[0083] 50A: Output axis center

[0084] 51: Output support body

[0085] 51a: Concave portion

[0086] 51b: Output sphere Detailed Embodiments

[0087] Next, a rocking reduction gear as an example of an embodiment of the present invention will be described with reference to Figures 1 to 10 the following.

[0088] As Figure 1 shown, in the X - Y - Z coordinate system, the rocking reduction gear 1 of the present embodiment includes: a main body 10 surrounding the entire device, an input shaft 20 rotatably held by the main body 10 about an input axis 20A, a precession body 30 that performs precession movement by the rotation of the input shaft 20, a rocking body 40 that engages with the precession body 30 above the precession body 30 in the Z - axis direction and rocks by precession movement, and an output shaft 50 that rotates about the Z - axis by the rocking of the rocking body 40.

[0089] As Figure 1 and FIG. 2 show, the main body 10 has: a front plate 11 rotatably supporting the input shaft 20, a rear plate 12 provided on the opposite side of the input shaft 20, a bottom plate 13 provided on the bottom surface, and a top plate 14 provided on the top surface. The main body 10 can be appropriately changed in shape according to the machine applied, such as the joint portion of a robot arm.

[0090] The input shaft 20 includes: a shaft portion 21 held by the front plate 11 of the main body 10 via an input bearing 15, and an eccentric portion 22 rotatably holding one precession shaft portion 32 of the precession body 30 at a position eccentric from the input axis 20A extending in the X - axis direction. In the eccentric portion 22, the front end portion of the precession shaft portion 32 is rotatably held by a precession bearing 23. When the input shaft 20 rotates, the eccentric portion 22 integrated with the shaft portion 21 also rotates, and the precession shaft portion 32 is eccentric and rotates, thereby enabling the precession body 30 to perform precession movement.

[0091] The precession body 30 includes: a spherical portion 31 formed in a spherical shape, and a pair of precession shaft portions 32 protruding on both sides along a precession axis 30A passing through the center 31c of the spherical portion 31. The precession axis 30A is an axis extending in the X - axis direction and having an eccentric angle of α in the front - rear direction. In the present embodiment, the angle α is set to 10°.

[0092] Figure 1 The left - hand precession shaft portion 32 in Figure 1 is supported by a precession bearing 23 provided in the eccentric portion 22 of the input shaft 20.

[0093] As shown in Fig. 3(A), on the surface of the spherical portion 31, a rocking annular groove 33 is formed on the upper surface thereof. The rocking annular groove 33 is a groove that guides the rocking body 40 to rock in the circumferential direction and the Z-axis direction with the output axis 50A in the Z-axis direction as the center during the precession motion of the precession motion body 30. In the present embodiment, eight rocking annular grooves 33 are formed on the upper surface of the spherical portion 31. In addition, in this case, in the partial drawing, in order to show the shape of the groove such as the rocking annular groove 33, a plurality of thin lines are used.

[0094] In addition, as shown in Fig. 3(B), below the spherical portion 31, a precession motion annular groove 34 is formed. The precession motion annular groove 34 is a groove formed along the locus depicted between the surface of the spherical portion 31 and a later-described precession motion support 16 when the precession motion of the precession motion body 30 is presented. In the present embodiment, six precession motion annular grooves 34 are formed on the lower surface of the spherical portion 31.

[0095] Refer to Figure 1 and Fig. 2(A), below the spherical portion 31, the precession motion support 16 that supports the precession motion body 30 is fixed to the bottom plate 13. In the present embodiment, the precession motion support 16 is provided with two in the X-axis direction and two on each of the left and right (Y-direction) in accordance with the position of the precession motion annular groove 34, for a total of six (refer to Fig. 2(A)).

[0096] The precession motion support 16 has a shape obtained by obliquely cutting a cylindrical member, and a concave portion 16a is provided on its inclined surface. A precession motion sphere 16b made of metal is rotatably held in the concave portion 16a. The precession motion sphere 16b rotates while abutting against the precession motion annular groove 34 during the precession motion of the precession motion body 30.

[0097] In addition, as Figure 1 shown, the precession motion support 16 is mounted on a fixed member 16c via a leaf spring 16d that serves as a precession energizing unit, and the fixed member 16c is fixed to a through hole in the bottom plate 13. With this structure, the precession motion support 16 is configured such that the precession motion sphere 16b is energized to the precession motion annular groove 34 of the precession motion body 30 by the elastic force of the leaf spring 16d that serves as an elastic member.

[0098] In addition, the precession motion support 16 is similar to a later-described rocking support 17 (refer to Figure 4 ), and the outer peripheral surface on the side fixed to the fixed member 16c is processed into a D shape, and rotation is prevented by a guide plate 13a fixed to the surface of the bottom plate 13.

[0099] As Figure 4As shown in FIG. 5, the entire shaking body 40 is formed in a dome shape. As shown in FIG. 5(B), hemispherical recesses 40a are provided on its inner peripheral surface. In the present embodiment, eight recesses 40a are provided, and the shaking spherical body 40b is rotatably held in the recesses 40a.

[0100] In addition, on the upper surface side of the shaking body 40, there are formed: a support portion 41 supported by the shaking support body 17, and a guiding portion 42 against which the output support body 51 of the output shaft 50 abuts via the output spherical body 51b. A shaking guiding groove 41a for guiding the shaking of the shaking body 40 is formed in the support portion 41. A wave-shaped groove 42a for converting the shaking of the shaking body 40 into the rotational movement of the output shaft 50 is formed in the guiding portion 42.

[0101] As Figures 5(A) to 5(C) shown, the shaking guiding groove 41a provided in the support portion 41 of the shaking body 40 is longitudinally elongated in the Z-axis direction. The shaking of the shaking body 40 is guided by the shaking guiding spherical body 17b held by the shaking support body 17 abutting against the shaking guiding groove 41a.

[0102] As Figure 4 shown, the shaking support body 17 is formed in a shape obtained by obliquely cutting a cylindrical member, and a recess 17a is provided on the inclined surface. The shaking guiding spherical body 17b is rotatably held in the recess 17a.

[0103] In addition, as shown in FIG. 2(B), the shaking support body 17 is mounted on the fixed member 17c via a leaf spring 17d as a shaking energizing unit, and the fixed member 17c is fixed to the through-hole of the top plate 14. With this structure, the shaking support body 17 is in a state of energizing the shaking guiding spherical body 17b to the shaking guiding groove 41a of the shaking body 40 via the elastic force of the leaf spring 17d as an elastic member.

[0104] As shown in FIG. 5(A), the wave-shaped groove 42a provided in the guiding portion 42 of the shaking body 40 continuously forms nine arc-shaped grooves 42b that move the output spherical body 51b in the circumferential direction by an amount corresponding to one cycle of the shaking of the shaking body 40. The output spherical body 51b rotatably held in the recess 51a provided in the output support body 51 of the output shaft 50 abuts against the wave-shaped groove 42a.

[0105] As shown in FIG. 5(A), in the present embodiment, nine arc-shaped grooves 42b corresponding to one cycle amount are provided over the entire circumference in the guiding portion 42. As Figure 4As shown in FIG. 5(C), eight output supports 51 mounted on the output shaft 50 abut against the corrugated groove 42a via output spheres 51b. The output support 51 has a shape obtained by obliquely cutting a cylindrical member, and a recess 51a is provided on this inclined surface. The output sphere 51b is rotatably held in the recess 51a.

[0106] Next, with reference to Figure 6 and Figure 7 , the relationship between the precession motion annular groove 34 and the precession motion sphere 16b when the precession motion body 30 performs precession motion will be described. Figure 6 In the state of Figure 7 , the left precession shaft portion 32 is at the lowermost part in the Z-axis direction. If this state is set as the initial position, the positional relationship between the precession motion annular groove 34 and the precession motion sphere 16b at this time is as shown in

[0107] The precession motion annular groove 34 is the locus of a certain fixed point (in this case, the precession motion sphere 16b) on the surface of the spherical portion 31 of the precession motion body 30 when it rotates at an angle α of the precession axis 30A with respect to the input axis 20A of the input shaft 20.

[0108] Specifically, if the coordinate position when the input shaft 20 rotates by an angle θ (°) from the initial position on the surface of the spherical portion 31 is set as P1, and the position obtained by coordinate conversion of P1 around the precession axis 30A is set as P2, then their coordinates are expressed by the following equations.

[0109] P1 = P o ·E 20A·θ (1)

[0110] P2 = P1·E 30A(-θ) (2)

[0111] In the above equations (1) and (2), E is the transformation matrix for the rotation θ about the input axis 20A of the input shaft 20. If the surface of the spherical portion 31 is machined along the locus represented by this equation using a tool having the same shape as the precession motion sphere 16b, the precession motion annular groove 34 is formed.

[0112] Next, with reference to Figure 8 , the rocking annular groove 33 of the spherical portion 31 of the precession motion body 30 will be described. The rocking annular groove 33 has a locus for causing the rocking body 40 to rock via the rocking sphere 40b rotatably held in the recess 40a of the rocking body 40 by the precession motion of the precession motion body 30.

[0113] As shown in Figure 8 , there are eight rocking annular grooves 33, each having a different shape. First, Figure 8The state shown is taken as the initial position, the position when the input shaft 20 is rotated by an angle θ (°) is calculated, and the trajectory is obtained by calculating the position obtained by coordinate conversion of this position through the wobbling axis 40A (refer to Fig. 5(C)) of the wobbling body 40. This trajectory is actually an intermediate imaginary trajectory that does not show a shape on the finished product and is a circular trajectory.

[0114] Furthermore, the trajectory of the wobbling annular groove 33 of the precession body 30 is obtained by deriving the precession motion of the precession body from this imaginary trajectory. For the calculation of the above trajectory, the transformation matrix is used in the same order as the calculation of the aforementioned precession motion annular groove 34, and the calculation of coordinates is repeated to calculate the trajectory of one cycle amount. Since the specific method is the same as the method in Patent Document 1, the detailed description is omitted here.

[0115] Next, with reference to Figure 9 , the relationship between the wavy groove 42a of the wobbling body 40 and the output sphere 51b is described. Figure 9 The position of the output sphere 51b of Figure 1 represents the initial position of the precession body 30 in the state shown in Figure 9 . In this state, among the 9 arc-shaped grooves 42b of the wavy groove 42a, 1 of the 8 output spheres 51b is located at the intersection point 42b1 of the 2 arc-shaped grooves 42b at the left end.

[0116] As shown in Figure 9 , since the number of output spheres 51b is 1 less than the number of arc-shaped grooves 42b, the position of the output sphere 51b becomes a position that shifts as it moves to the right. Here, when the input shaft 20 is rotated once from the state of Figure 9 , the wobbling body 40 will wobble once, the output sphere 51b rotates through the arc-shaped groove 42b, and the output sphere 51b at the left end moves to the intersection point 42b2 of the arc-shaped groove 42b above and to its right. If the input shaft 20 is further rotated, the above actions are performed in sequence. When the input shaft 20 is rotated 9 times, which is the same as the number of arc-shaped grooves 42b, it returns to the initial position shown in Figure 9 .

[0117] As described above, the number of arc-shaped grooves 42b in the wavy groove 42a becomes the reduction ratio of the output shaft 50 with respect to the input shaft 20. Therefore, in the case of wanting to increase the reduction ratio, the number of arc-shaped grooves 42b can be increased. In addition, regarding the method of forming this wavy groove 42a, since it is the same as the method in Patent Document 1, the detailed description is omitted here.

[0118] The wobble-type reduction gear 1 of the present embodiment causes the precession body 30 to perform precession motion by the rotation of the input shaft 20, and causes the wobble body 40 engaged with the precession body 30 to wobble. Further, the wobbling motion of the wobble body 40 is converted into the rotational motion of the output shaft 50 by the mechanism of the wave-shaped groove 42a, the output sphere 51b, and the output support 51.

[0119] With this structure, since the wobble-type reduction gear 1 of the present embodiment does not use gears or the like when reducing the input rotation, the device can be miniaturized and the backlash can be extremely reduced.

[0120] In addition, in the wobble-type reduction gear 1 of the present embodiment, both the wobbling annular groove 33 and the precession motion annular groove 34 that require high machining accuracy are formed on the surface of the spherical portion 31 of the precession body 30. When forming such grooves, if it is the surface of the spherical portion 31, machining with a machining tool of an automatic machining machine can be easily performed.

[0121] In addition, even when the diameter of the spherical portion 31 is reduced, machining with a machining tool of an automatic machining machine can be easily performed. For example, when machining such grooves on the inner peripheral surface of the wobble body 40, since the machining is performed within the range where the tool does not interfere with the wobble body 40, the machining area becomes narrow, and there may be a case where machining is difficult when miniaturizing. In the present embodiment, by machining the grooves on the surface of the spherical portion 31, precise machining can be performed even in the case of miniaturization.

[0122] On the other hand, by providing grooves on the surface of the spherical portion 31, energization caused by an elastic body may occur in the wobble sphere 40b and the precession motion sphere 16b that come into contact with these grooves. The precession body 30 is supported by the precession motion support 16 and the precession motion sphere 16b mounted on the bottom plate 13 via the leaf spring 16d. In addition, the wobble body 40 is supported by the wobble support 17 and the wobble guide sphere 17b mounted on the top plate 14 via the leaf spring 17d.

[0123] Therefore, even when a high load is applied to the wobble-type reduction gear 1 and high loads are applied to the respective members, since the loads generated in the precession body 30 and the wobble body 40 are absorbed by the leaf spring 17d and the leaf spring 16d, respectively, the influence on the respective members can be minimized. Therefore, it is possible to improve the load resistance and durability of the wobble-type reduction gear 1.

[0124] Next, with reference to Figure 10 , a modification of the wobble-type reduction gear of the present embodiment will be described. Figure 10 FIG. is a diagram showing the precession motion support 16e of the wobble-type reduction gear 1a as a modification. Figure 10The precession motion support body 16e in [it] is a cylindrical member that extends from the bottom plate 13b of the main body 10a toward the center 31c of the spherical portion 31 of the precession motion body 30. In addition, in the description of the modified example, members having the same structure as those in the above-described embodiment are given the same reference numerals and detailed descriptions thereof are omitted.

[0125] The basic shape of the precession motion support body 16e in this modified example is cylindrical, and a precession motion sphere 16b is rotatably held at its front end. The precession motion support body 16e is, as in the above-described embodiment, mounted on the bottom plate 13b via a leaf spring and is mounted on the bottom plate 13b so as to be movable in the axial direction. Alternatively, the precession motion support body 16e can be energized to the precession motion annular groove 34 by other energizing units such as a coil spring.

[0126] Since the precession motion support body 16e in this modified example has the above-described structure, even when a strong load is applied to the precession motion body 30 from the output shaft 50, the load on the precession motion body 30 can be evenly dispersed and absorbed by each precession motion support body 16e and the energizing unit.

[0127] In addition, in each of the above-described embodiments, the angle α between the input axis 20A of the input shaft 20 and the precession axis 30A of the precession motion body 30 is set to 10°, but it is not limited thereto. As long as it is in the range of 0° < α ≤ 20°, various changes can be made according to the size of the entire device or the reduction ratio.

[0128] Further, the crossing angle between the input axis 20A and the output axis 50A is set to 90° in the above-described embodiment, but it is not limited thereto. The crossing angle can be changed within the range of plus or minus 20°. In addition, the number and shape of the rocking annular groove 33 and the precession motion annular groove 34 provided on the surface of the spherical portion 31 of the precession motion body 30 can also be appropriately changed according to the size of the spherical portion 31 and the like.

Claims

1. A rocking type reduction gear device, characterized in that, In the X-Y-Z coordinate system, it is composed of the following components: An input shaft, which is rotatably supported on the main body with the input axis extending in the X-axis direction as the center; A precession body, having a spherical portion and a pair of precession axis portions. The pair of precession axis portions protrude from both sides along the precession axis passing through the center of the spherical portion. One of the precession axis portions is held on the input shaft in a manner capable of performing precession movement with the X-axis as the center; A precession movement support body, which supports the precession body in a precession movement-free manner relative to the main body and is fixed to the main body; A rocking body, in the Z-axis direction, is engaged with the surface of the precession body on the side opposite to the precession movement support body side, and rocks through the precession movement of the precession body; A rocking support body, which is engaged with the rocking body and supports the rocking of the rocking body relative to the main body; and An output shaft, with the Z-axis direction as the axis, is rotatably supported on the main body, is engaged with the rocking body, and rotates through the rocking of the rocking body; On the surface of the precession body on the precession movement support body side, a precession movement annular groove is provided. The precession movement annular groove is formed by setting the trajectory depicted between the precession body and the precession movement support body during the precession movement of the precession body as a groove. A precession movement sphere rotating freely in the precession movement annular groove is rotatably held on the precession movement support body; On the surface of the precession body on the rocking body side, a rocking annular groove is provided. The rocking annular groove rocks the rocking body in the circumferential direction and the Z-axis direction with the Z-axis as the center during the precession movement of the precession body. A rocking sphere rotating freely in the rocking annular groove is rotatably held on the surface of the precession body on the rocking body side; On the surface of the rocking body on the rocking support body side, a rocking guide groove is provided. The rocking guide groove guides the rocking movement of the rocking body. A rocking guide sphere rotating freely in the rocking guide groove is rotatably held on the rocking support body; On the surface of the rocking body on the output shaft side, a wave-shaped groove is provided over the entire circumference. The wave-shaped groove is formed by a plurality of continuous arc-shaped grooves with an amount corresponding to one cycle of the rocking of the rocking body. An output sphere rotating freely in the wave-shaped groove is rotatably held on the output shaft.

2. The rocking type reduction gear according to claim 1, characterized in that The precession movement support body is provided with a precession energy-giving unit, and the precession energy-giving unit is installed on the main body via an elastic member to give energy to the precession movement sphere toward the precession movement annular groove.

3. The rocking type reduction gear according to claim 2, characterized in that The precession movement support body faces the center of the spherical portion and gives energy to the precession movement sphere toward the precession movement annular groove.

4. The rocking type reduction gear according to any one of claims 1 to 3, characterized in that The rocking support body is provided with a rocking energy-giving unit, and the rocking energy-giving unit is installed on the main body via an elastic member to give energy to the rocking guide sphere toward the rocking guide groove.

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