JP6208820B2 - Reduction gear - Google Patents

Description

  The present invention relates to a reduction gear including a main bearing interposed between an output member and a fixing member.

  Patent Document 1 discloses a reduction gear including a pair of angular roller bearings using cylindrical rollers as a main bearing interposed between an output member and a fixing member. This angular roller bearing includes a dedicated inner ring and an outer ring that support the cylindrical roller. Of these, the inner ring has a “hook”, and the axial movement of the cylindrical roller is restricted by this “hook” so that the cylindrical roller does not come off the inner ring and the outer ring.

JP 2003-74646 A (paragraph [0012], FIG. 4)

  As disclosed in Patent Document 1, a main bearing having an inner ring or an outer ring provided with a “river” for suppressing the axial movement of the cylindrical roller is a workability of the inner ring or outer ring having the flange. However, because of the high hardness of the material, there is a problem that it is easy to increase the cost.

  The present invention has been made to solve such a conventional problem, and an object of the present invention is to provide a speed reducer in which the workability of the main bearing is high and the cost can be reduced.

The present invention includes a casing, an internal gear, an external gear that is in mesh with the internal gear, an eccentric shaft that swings the external gear, and a flange that supports the eccentric shaft , A reduction gear including a casing and a main bearing that rotatably supports the flange body, wherein the main bearing is disposed between an outer ring and an inner ring, and is a rotation shaft that is inclined with respect to the axis of the internal gear. A plurality of rollers having a plurality of rollers, and retainers that hold the plurality of rollers, wherein the inner ring and the outer ring have no flanges that restrain movement of the rollers in the axial direction, and the retainers contact the casing By doing so, the above-mentioned problems are solved.

  According to the present invention, it is possible to obtain a speed reducer that has high workability of the main bearing and that can reduce costs.

Sectional drawing of the speed reducer which concerns on the reference example of this invention 1 is an enlarged view of the main part of FIG. A perspective view in which a cylindrical roller is incorporated in the retainer Partial enlarged front view of retainer Enlarged view of the main parts near the first and second main bearings FIG. 6 is an enlarged view of a main part in the vicinity of an enlarged view corresponding to FIG. 5 showing a modification of the shape of the first and second main bearings, where FIG. Enlarged view Sectional drawing which shows the example of the speed reducer which concerns on the other reference example of this invention.

  Hereinafter, a reference example of the present invention will be described in detail with reference to the drawings.

  In the following, a simple “cylindrical roller” is used as the rolling element of the main bearing. Rolling elements made of “cylindrical rollers” are less expensive than, for example, tapered rollers, and the rotating shaft and the outer periphery (the surface in contact with the rolling surface) are parallel, so the component force that moves in the axial direction Basically does not occur (even if it occurs due to manufacturing error, assembly error, etc.). Therefore, the retainer is provided with this function by deliberately omitting the formation of a “ridge” for restricting the axial movement of the cylindrical roller in the inner and outer rings. For this reason, the shape of the inner and outer rings of the main bearing can be simplified, extremely good workability can be obtained, and simplification of processing and cost reduction can be realized. Moreover, a rotation loss can be reduced compared with the case where there exists a collar part.

  Moreover, the cylindrical roller in the following description has the rotating shaft inclined with respect to the axis line of an output member. Therefore, both radial and thrust loads can be received. In addition, since the rotating shaft of the cylindrical roller is inclined with respect to the axis of the output member, when the cylindrical roller is disposed between the fixed member and the output member in a state where each cylindrical roller is supported by the retainer, the retainer is cylindrical. In the axial direction of the rotating shaft of the roller, it becomes impossible to move to either the large diameter side or the small diameter side, so that a positioning mechanism for the retainer itself is basically unnecessary. For this reason, it is easy to incorporate the retainer in a state where the cylindrical roller is supported.

  In the following description, “output member” and “fixing member” are relative. For example, when it is applied for joint driving of a robot, the output member and the fixing member are reversed if the member of interest is changed. Further, since the joint of the robot itself is moving, the output member and the fixing member are moving when viewed from the factory base. That is, the fixing member is not necessarily used in the sense that it is absolutely stopped. However, among the members of the speed reducer, the output member rotates at a very slow relative rotational speed and a very large torque with respect to the fixed member. The “main bearing” is interposed between the casing constituting the output member and the fixing member and the flange body, and the relative rotational speed is very low (for example, 100 rpm or less) among the bearings of the speed reducer, but the handled torque is very high. This means a bearing used in a large part (or a part equivalent thereto).

  FIG. 1 is a cross-sectional view of a reduction device for a robot precision control machine to which an example of a reference example of the present invention is applied, and FIG. 2 is an enlarged view of a main part thereof.

  The speed reduction device 2 is used for controlling the robot, for example, backlash of 15 minutes (15/60 degrees) to 2 minutes (2/60 degrees), and 2 minutes (2/60 degrees) when the precision is higher. ) Used for precision machines of about 0.3 minutes (0.3 / 60 degrees), the speed reducing mechanism 5 having a parallel shaft gear structure that receives the driving force from the motor 4 in the front stage, and the intermeshing planet in the rear stage A reduction mechanism 6 having a gear structure is provided. The speed reduction device 2 is disposed between a first member 8 and a second member 10 of a robot (the whole is not shown), and drives the second member 10 to rotate relative to the first member 8. Accordingly, in this reference example, first and second flange bodies 12 and 14 described later correspond to a fixing member, and the casing 16 corresponds to an output member. That is, it is a so-called frame rotation type reduction device.

  A specific configuration will be described in detail below.

  The motor 4 is fixed to the first member 8 of the robot via bolts 22. A joint 26 is connected to the motor shaft 24 of the motor 4. A pinion 28 is formed at the tip of the joint 26. The pinion 28 meshes simultaneously with the three sorting gears 30A to 30C. 1 and 2, only the sorting gear 30A among the three sorting gears 30A to 30C is depicted.

  Each of the sorting gears 30A to 30C is incorporated in three eccentric body shafts 32A to 32C (only the eccentric body shaft 32A is depicted in FIGS. 1 and 2).

  The eccentric body shafts 32A to 32C are supported by the first and second flange bodies 12 and 14 via tapered roller bearings 34 and 36, respectively. Eccentric bodies 40A to 40C and 42A to 42C are integrally formed with the eccentric body shafts 32A to 32C (only the eccentric bodies 40A and 42A of the eccentric body shaft 32A are depicted in FIGS. 1 and 2). The eccentric bodies incorporated in the same eccentric body shaft, for example, the eccentric bodies 40A and 42A incorporated in the eccentric body shaft 32A have an eccentric phase of 180 degrees. The eccentric bodies at the same position in the axial direction of the eccentric body shafts 32A to 32C, for example, the eccentric body 40A of the eccentric body shaft 32A, the eccentric body 40B of the eccentric body shaft 32B, and the eccentric body 40C of the eccentric body shaft 32C are the same. Built in with an eccentric phase of. The eccentric body 42A of the eccentric body shaft 32A, the eccentric body 42B of the eccentric body shaft 32B, and the eccentric body 42C of the eccentric body shaft 32C are also incorporated with the same eccentric phase.

  With these configurations, each of the eccentric body shafts 32A to 32C can be rotated integrally with the respective sorting gears 30A to 30C in the same direction at the same speed, and the eccentric body shafts 32A to 32C can be rotated by the rotation of the eccentric body shafts 32A to 32C. 40A, 40B, and 40C rotate in the same phase as a set, and similarly, the set of eccentric bodies 42A, 42B, and 42C rotate in the same phase. The eccentric phase of the set of eccentric bodies 40A, 40B, and 40C and the eccentric phase of the set of eccentric bodies 42A, 42B, and 42C are shifted from each other by 180 degrees.

  On the other hand, the reduction gear 2 includes two external gears 44 and 46 and an internal gear 48 in which the external gears 44 and 46 are in mesh with each other. The external gear 44 includes eccentric body shaft holes 44A, 44B, 44C corresponding to the eccentric body shafts 32A to 32C (FIGS. 1 and 2 show only the eccentric body shaft hole 44A corresponding to the eccentric body shaft 32A. Similarly, the external gear 46 also includes eccentric body shaft holes 46A, 46B, 46C corresponding to the eccentric body shafts 32A to 32C (FIGS. 1 and 2 show the eccentric body shaft corresponding to the eccentric body shaft 32A). Only the hole 46A is shown).

  The eccentric bodies 40A, 40B, and 40C of the eccentric body shafts 32A to 32C are fitted into the eccentric body shaft holes 44A, 44B, and 44C of the external gear 44 through rollers 48A to 48C (only the roller 48A is illustrated). . The eccentric bodies 42A, 42B, 42C of the eccentric body shafts 32A-32C are fitted into the eccentric body shaft holes 46A, 46B, 46C of the external gear 46 via rollers 50A-50C (only the roller 50A is shown). .

  With this configuration, the set of eccentric bodies 40A, 40B, and 40C of the eccentric body shafts 32A to 32C and the set of eccentric bodies 42A, 42B, and 42C are rotated in the same direction at the same speed, respectively. The toothed gears 44 and 46 are configured to swing eccentrically with a phase difference of 180 degrees.

  The two external gears 44 and 46 are in mesh with the internal gear 48. The internal gear 48 is integrated with the casing 16. The casing 16 is fixed to the second member 10 of the robot via a bolt 56 and functions as an “output member”. The internal teeth of the internal gear 48 are constituted by a cylindrical outer pin 52. The number of teeth of the external gears 44 and 46 is N, and the number of teeth of the internal gear 48 (the number of external pins 52) is N + 1. That is, the number of teeth of the internal gear 48 is one more than the number of teeth of the external gears 44 and 46.

  Here, each eccentric body axis | shaft 32A-32C is rotatably supported by the 1st, 2nd flange bodies 12 and 14 via the tapered roller bearings 34 and 36. As shown in FIG. The first and second flange bodies 12 and 14 are connected by a bolt 58. A first main bearing 18 is provided between the first flange body 12 and the casing 16. A second main bearing 20 is provided between the second flange body 14 and the casing 16.

  The first and second main bearings 18 and 20 are arranged on the outer periphery of the first and second flange bodies (fixing members) 12 and 14, and the casing (output member) 16 is connected to the first and second flange bodies 12 and 14. On the other hand, among the members in the speed reducer 2, it is supported so as to be rotatable at the slowest relative rotational speed (for example, 100 rpm or less) and with the largest torque. In this reference example, both the first and second flange bodies 12 and 14 are integrally fixed to the first member 8 of the robot as fixed members. For this reason, when the casing 16 rotates relative to the first and second flange bodies 12 and 14, as a result, the first member 8 of the robot integrated with the first and second flange bodies 12 and 14 is used. Thus, the second member 10 of the robot integrated with the casing 16 rotates relatively.

  Next, the configuration in the vicinity of the first and second main bearings 18 and 20 will be described in detail with reference to FIGS.

  The 1st, 2nd main bearings 18 and 20 are provided with a pair of cylindrical roller rows 60 and 61 incorporated in the back combination as the rolling element. Each cylindrical roller row 60, 61 is composed of a plurality of cylindrical rollers 60A, 61A arranged so as to have rotational axes O2, O3 inclined by 45 degrees with respect to the axis O1 of the first and second flange bodies 12, 14. Has been. As these cylindrical rollers 60A and 61A, cylindrical rollers having the same diameter and height (axial length) used for so-called cross roller bearings can be diverted. That is, since the cross roller can be shared, further cost reduction can be achieved.

  Unlike the tapered rollers, the cylindrical rollers 60A and 61A are basically parallel to the rotating shaft and the outer periphery (the contact lines on the casing 16 side and the contact lines on the first and second flange bodies 12 and 14 side). No thrust force component is generated during operation. Focusing on this point, in this reference example, the inner rings 64 and 66 and the outer rings 68 and 70 of the first and second main bearings 18 and 20 are made to have an isosceles cross section perpendicular to the circumferential direction (of the inner and outer rings). The triangular shape is omitted, and so-called “ridges” for restricting the axial movement of the cylindrical rollers 60A and 61A are omitted. In addition, the retainers 74 and 76 suppress the axial movement of the cylindrical rollers 60A and 61A that may actually occur due to reasons such as manufacturing errors and assembly errors.

  The first main bearing 18 and the second main bearing 20 are incorporated symmetrically, and are basically the same in configuration including the inner rings 64 and 66, the outer rings 68 and 70, and the retainers 74 and 76. Therefore, for the sake of convenience, the following description will be made in detail with a focus on the second main bearing 20 side, and redundant description of the first main bearing 18 will be omitted.

  The retainer 76 according to the second main bearing 20 of this reference example is made of resin. It may be made of iron or steel.

  FIG. 3 is a perspective view showing a state in which the cylindrical roller 61A is incorporated (only some of the cylindrical rollers are removed). FIG. 4 is an enlarged view of a part of the retainer 76 in a state in which the cylindrical roller 61A is removed. It is the shown front view. The retainer 76 is formed with a plurality of pockets 76A (as many as the number of cylindrical rollers) for assembling the cylindrical rollers 61A, and a recess (engagement) for rotatably holding the cylindrical rollers 61A on the inner periphery of each pocket 76A. Stop part) 76B is formed. The cylindrical roller 61A is incorporated into the pocket 76A so as to be pushed in by utilizing the elasticity of the resin (elastic deformation around the pocket 76A). The cylindrical roller 61A once incorporated in each pocket 76A is supported by the recess 76B on the inner periphery of the pocket and can freely rotate. By incorporating all the cylindrical rollers 61 </ b> A into the retainer 76, the rolling element assembly 80 is formed as if the collar is also one part (the whole is substantially in the shape of a truncated cone).

  FIG. 5 is an enlarged view of a main part in the vicinity of the second main bearing 20 of FIGS. 1 and 2. The inner ring 66 and the outer ring 70 of the second main bearing 20 have a cross section perpendicular to the circumferential direction of the inner and outer rings of a substantially right isosceles triangle, and a flange for restricting the movement of the cylindrical roller 61A in the axial direction is particularly provided. It is not done. The hypotenuses of right angled isosceles triangles in the cross section of the inner ring 66 and the outer ring 70 constitute rolling surfaces 66A and 70A of the cylindrical roller 61A. The axial lengths L1 and L2 of the rolling surfaces 66A and 70A are substantially the same as the axial length L0 of the cylindrical rollers 61A.

  When the outer ring 70 is assembled into the casing 16 from the axial direction (right side in this example), a pressed portion 70B (perpendicular to the shaft) that serves as a pressure receiving surface when assembled is formed. . Further, when the inner ring 66 is assembled into the second flange body 14 from the axial direction (left side in this example), a pressed portion 66B (perpendicular to the axis) that serves as a pressure receiving surface when assembled. Is formed.

  The outer ring 70 restricts the axial movement of the outer pin 52 that constitutes the inner teeth of the internal gear 48 at the axial inner side surface 70C thereof. Further, the movement of the external gears 44 and 46 in the axial direction is also restricted (also serves as movement restriction means for the external pin 52 and the external gears 44 and 46).

  Since the entire rolling element assembly 80 is substantially in the shape of a truncated cone, the entire rolling element assembly 80 is basically formed of the cylindrical roller 61A without the support (movement restraint) of the retainer 76 in the axial direction. It cannot move in the axial direction (cannot move). Therefore, in this reference example, a configuration for restricting the movement of the retainer 76 in the axial direction is not particularly employed.

  In this reference example, the flat surfaces 66C and 70C are formed not only on the pressed surfaces 66B and 70B but also on the side end on the opposite side of the rolling surface. (There is no need for pressing), and the width may be narrower than the pressed surfaces 66B and 70B. In this case, further downsizing can be achieved.

  In addition, since the first and second main bearings 18 and 20 have a contact angle set to 45 °, the operating point span can be increased and the load acting on the bearing can be reduced. Longer life is possible.

  For example, a configuration as shown in FIGS. 6A and 6B can be adopted as a shape modification of the second (same as the first) main bearing. As shown in FIG. 6A, the axial lengths L3 and L4 of the rolling surfaces 84A and 86A of the inner ring 84 and the outer ring 86 of the second main bearing 82 are formed shorter than the axial length L0 of the cylindrical roller 61A. You may make it do. When the axial lengths L3 and L4 of the rolling surfaces 84A and 86A of the inner ring 84 and the outer ring 86 are formed to be shorter than the axial length Lo of the cylindrical roller 61A, coupled with the absence of the flange, further rotation loss The inner ring 84 and the outer ring 86 can be made more compact, and the overall size of the second main bearing 82 can be further reduced.

  6B corresponds to an example of the embodiment of the present invention. In the example of the second main bearing 91, a pressed surface 92A having a cross section perpendicular to the circumferential direction of the inner ring 92 and the outer ring 94, The inner ring 92 and the outer ring 94 are minimized by eliminating 94A. That is, the cross section is a right isosceles triangle. A part of the retainer 90 is in contact with the casing 16 and the external gear 46, respectively. In such a configuration, the second main bearing 91 can be further reduced in size, and the axial movement of the retainer 90 can also be restrained by the contact, so that the cylindrical roller 61A is placed in the retainer 90. The internal stress (compressed or pulled) generated in the retainer 90 when attempting to move in the axial direction can be further reduced.

  These configurations are also possible on the first main bearing 18 side.

  Next, the operation of the speed reducer 2 will be described.

  The movements of the first member 8 and the second member 10 of the robot are relative, but for the sake of convenience, it is assumed that the first member 8 is in a fixed state, and the operation of the reduction gear 2 is performed. explain.

  When the motor shaft 24 of the motor 4 rotates, the joint 26 connected to the motor shaft 24 rotates, and the pinion 28 formed at the tip of the joint 26 rotates. When the pinion 28 rotates, the sorting gears 30A to 30C meshing with the pinion 28 rotate, and the eccentric body shafts 32A to 32C rotate in the same direction at the same rotational speed. When the eccentric body shafts 32A to 32C are rotated, the external gear 44 is eccentrically oscillated through the eccentric bodies 40A to 40C and the cylindrical rollers 48A to 48C, and the external gears 44A to 42C and the cylindrical rollers 50A to 50C are externally moved. The toothed gear 46 swings eccentrically.

  In this configuration example, the eccentric body shafts 32A to 32C pass through the eccentric body shaft holes 44A to 44C of the external gear 44 and the eccentric body shaft holes 46A to 46C of the external gear 46, respectively. Further, the eccentric body shafts 32A to 32C can be rotated (spinned) by the tapered roller bearings 34 and 36, but the assembling positions with respect to the first and second flange bodies 12 and 14 are fixed. Therefore, the external gears 44 and 46 through which the eccentric body shafts 32A to 32C pass are constrained to rotate and only swing by the rotation of the eccentric body shafts 32A to 32C. And the meshing position will shift sequentially. As a result, each time the external gears 44 and 46 are swung once, the internal gear 48 is phase-shifted with respect to the external gears 44 and 46 by the difference in the number of teeth “1 / (N + 1)” from the external gears 44 and 46. Shifts (rotates). The rotation of the internal gear 48 appears as the rotation of the casing 16 integrated with the internal gear 48, and the second member 10 of the robot (with respect to the first member 8 of the robot) is connected via the bolt 56. Rotate). Note that this (relative) rotation speed is at most 100 rpm in the case of the robot drive speed reduction device 2 as in this configuration example, for example. With such a rotational speed, “cylindrical rollers” can be sufficiently practical. In other words, if the speed is higher than this, the difference in speed between the inner ring side and the outer ring side becomes large, and there is a possibility that the grease may dry due to heat generation and eventually damage may occur, which is not preferable.

  Here, since the cylindrical rollers 60A and 61A of the first and second main bearings 18 and 20 are simple “cylindrical rollers”, the cost is low, and the rotation shafts O2 and O3 are parallel to the outer periphery. There is basically no component force to move in the axial direction. Therefore, the axial movement of each cylindrical roller 60A, 61A can be sufficiently restricted only by supporting the cylindrical rollers 60A, 61A by the retainers 74, 76.

  Therefore, the inner rings 64 and 66 and the outer rings 68 and 70 do not need to form so-called flanges for restricting the axial movements of the cylindrical rollers 60A and 61A, and a simple shape having a substantially right-angled isosceles triangle. Thus, the processing man-hours and processing costs, and thus the cost of the reduction gear can be greatly reduced. Furthermore, rotation loss can be reduced.

  Further, both the inner rings 64 and 66 and the outer rings 68 and 70 are assembled when the inner rings 64 and 66 or the outer rings 68 and 70 are assembled into the casing 16 or the first and second flange bodies 12 and 14 from the axial direction. Since the pressed portions 66B and 70B (in the case of the second main bearing 20) serving as the pressure receiving surfaces are formed, the cross section perpendicular to the circumferential direction of the inner and outer rings has a basic shape. Despite being a right-angled isosceles triangle, assembly can be performed easily and reliably.

  Further, such a plurality of cylindrical rollers 60A, 61A have rotating shafts O2, O3 inclined by 45 degrees with respect to the axis O1 of the casing 16 as an output member, and “a pair of cylindrical roller rows 60 aligned on the back surface,” 61 ”, it is possible to receive both radial and thrust loads well over a wide operating span, and to properly receive the torsional load when the first and second members of the robot rotate relative to each other. it can. Further, the cylindrical rollers 60A and 61A are in line contact with the rolling surfaces 66A and 70A (in the case of the second main bearing 20) of the inner and outer rings, so that the load resistance is large and the backlash is small.

  In the present invention, the specific configuration of the reduction gear is not particularly limited. The configuration for inputting power from the motor to the reduction gear is not particularly limited to the above configuration example. Further, for example, a simple planetary gear mechanism may be adopted as the reduction mechanism, or a reduction gear mechanism of an internally meshed planetary gear structure of a so-called center crank type as shown in FIG. You may have.

  7 includes an input shaft 102, eccentric bodies 104 and 106 formed integrally with the input shaft 102, and swings on the outer periphery of the eccentric bodies 104 and 106 via rollers 108 and 110. External gears 112 and 114 that are rotatably incorporated, and an internal gear 116 in which the external gears 112 and 114 mesh with each other.

  The external gears 112 and 114 and the internal gear 116 have a slight difference in the number of teeth (for example, 1).

  The internal gear 116 is integrated and fixed with the casing 118. Further, the rotation components of the external gears 112 and 114 are taken out from the first and second flange bodies 122 and 124 integral with the inner pin 120 through the inner pin 120. The input shaft 102 is supported by the first and second flange bodies 122 and 124 via a pair of bearings 126 and 128.

  Even in the speed reducer having such a configuration, the first and second main bearings 18 and 20 having the same configuration as in the above configuration example can be applied and incorporated as they are, and the same operation and effect can be obtained.

  In the above configuration example, the cylindrical roller is set to be incorporated so as to be inclined by 45 degrees with respect to the axis lines of the first and second flange bodies. However, in the present invention, the cylindrical roller is set with respect to the axis line of the cylindrical roller. The inclination is not limited to 45 degrees. In this regard, in the above configuration example, the shape of the cross section perpendicular to the circumferential direction of the inner and outer rings is formed into a substantially right angled isosceles triangle, but it is not necessarily required to be a right angled isosceles triangle.

  In the above configuration example, when the inner ring or the outer ring is assembled into the casing (output member) or the first and second flange bodies (fixing member) from the axial direction in the inner ring and the outer ring of the first and second main bearings. The pressed portion perpendicular to the axis serving as the pressure receiving surface at the time of assembling is formed, but the pressed portion is not necessarily formed.

  In addition, you may give a crowning process to the axial direction both ends of the cylindrical roller which is a rolling element. In this case, when the crowning portion at the axially outer end portion is formed larger than the crowning amount at the crowning portion at the axially inner end portion of the speed reducer 2, torsional displacement occurs on the inner ring side and the outer ring side of the main bearing. In this case, it is possible to satisfactorily cope with a phenomenon in which the displacement is larger on the outer side in the axial direction and the edge load is likely to stand. Of course, it is good also as a crowning part of the same magnitude | size, a crowning part may be formed only in an axial direction outer side end, and it is not necessary to form at all.

  Further, in the above configuration example, the external gears 44 and 46 are pressed by the outer rings 68 and 70, but the pressed surface of the inner ring is extended in the axial direction of the reduction gear so as to press the external gear. Also good. Conversely, the outer ring or the inner ring may be configured not to have such a pressing function.

  It is particularly useful as a speed reducer for driving precision control machines such as robots and machine tools.

DESCRIPTION OF SYMBOLS 2 ... Deceleration apparatus 4 ... Motor 5 ... Deceleration mechanism of parallel shaft gear structure 6 ... Deceleration mechanism of internal meshing planetary gear structure 8 ... 1st member of robot 10 ... 2nd member of robot 12 ... 1st flange body 14 ... 1st 2 flange body 16 ... casing 32 ... input shaft 60, 61 ... cylindrical roller train 60A, 61A ... cylindrical roller 64, 66 ... inner ring 68, 70 ... outer ring 74, 76 ... retainer

Claims (3)

A casing, an internal gear, an external gear that meshes internally with the internal gear, an eccentric shaft that swings the external gear, a flange that supports the eccentric shaft , the casing, and the casing In a speed reducer including a main bearing that supports a flange body in a relatively rotatable manner,
The main bearing has a plurality of rollers disposed between an outer ring and an inner ring and having a rotation shaft inclined with respect to the axis of the internal gear, and a retainer that holds the plurality of rollers.
The inner ring and the outer ring do not have a flange portion that restricts the axial movement of the rollers,
The reduction device according to claim 1, wherein the retainer is in contact with the casing. In claim 1,
The internal gear is constituted by an outer pin incorporated in the casing, and the movement of the outer pin in the axial direction of the internal gear is regulated by the outer ring. In claim 1 or 2,
An eccentric bearing for supporting the eccentric body shaft on the flange body;
The speed reducing device, wherein the main bearing and the eccentric body bearing overlap each other when viewed from the radial direction.

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