CN105452716A - Eccentric rocking-type gear device - Google Patents

Abstract

The eccentric swing type gear device (1) comprises: a crankshaft (20) having an eccentric portion (20a); a swing gear (24) linked with the eccentric portion (20a); The outer cylindrical part (2) of the gear pin (3); the gear carrier (4) supporting the crankshaft (20) as a free rotation; the main bearing that allows relative rotation between the outer cylindrical part (2) and the gear carrier (4) (6); and a transmission gear (18) having an inner hole (18a). The crankshaft (20) is pressed into the inner hole (18a) of the transmission gear (18) to limit the displacement of the transmission gear (18) relative to the crankshaft (20).

Description

Eccentric oscillating gear unit

technical field

The present invention relates to an eccentric oscillating type gear unit.

Background technique

Conventionally, an eccentric oscillating type gear unit as described in Patent Document 1 has been known as a reduction gear capable of obtaining a large reduction ratio. As shown in FIG. 5 , the gear device disclosed in Patent Document 1 transmits the rotational driving force of the motor 61 to the crankshaft 64 via the input shaft 62 and the transmission gear 63 to rotate the crankshaft 64 . The transmission gear 63 is spline-coupled to the end of the crankshaft 64 . Therefore, the transfer gear 63 is restricted from rotating relative to the crankshaft 64 . In addition, a pair of stop rings 65 are attached to the crankshaft 64 so as to sandwich the transmission gear 63 . The transmission gear 63 is restricted by the pair of retaining rings 65 so that the transmission gear 63 does not move axially relative to the crankshaft 64 .

In the gear device described in Patent Document 1, the transmission gear 63 is sandwiched by a pair of retaining rings 65 to restrict the displacement of the transmission gear 63 relative to the crankshaft 64 . Therefore, it is necessary to protrude the crankshaft 64 from the transmission gear 63 . Therefore, as a gear unit, the axial length becomes long. Furthermore, since the transmission gear 63 is spline-coupled to the crankshaft 64, there is play in the axial direction and the rotational direction, which causes wear and vibration.

patent documents

Patent Document 1: Japanese Patent Laid-Open No. 2010-286098

Contents of the invention

It is an object of the present invention to suppress the axial length of the eccentric oscillating gear unit and eliminate play of the transmission gear relative to the crankshaft.

Regarding the present invention, an eccentric oscillating gear device according to a technical solution of the present invention includes: a crankshaft having an eccentric portion; a oscillating gear having teeth and interlocking with the eccentric portion; an outer cylinder portion, the The outer cylindrical portion has internal teeth meshing with the tooth portion of the swing gear; the inner cylindrical portion supports the crankshaft in a rotatable manner; and the main bearing allows the outer cylindrical portion and relative rotation between the inner cylindrical parts; and a transmission gear having an inner hole into which the crankshaft is pressed to limit the movement of the transmission gear relative to the crankshaft displacement.

Description of drawings

FIG. 1 is a diagram showing the configuration of an eccentric oscillation gear device according to an embodiment of the present invention.

Fig. 2 is a diagram for explaining a fixing structure of a transmission gear in the gear device.

FIG. 3 is a diagram showing a main part of an eccentric oscillating gear device according to another embodiment of the present invention.

FIG. 4 is a diagram showing a main part of an eccentric oscillating gear device according to another embodiment of the present invention.

FIG. 5 is a diagram showing the structure of a conventional eccentric oscillation type gear device.

detailed description

Hereinafter, modes for implementing the present invention will be described in detail with reference to the drawings.

The gear device 1 according to the present embodiment is a gear device applied as a reduction gear to, for example, a rotating body of a robot, a rotating part such as a wrist joint, or a rotating part of various machine tools. The gear device 1 is, for example, a gear transmission device provided between a base and a rotating body that rotates relatively thereto, and outputs a driving force having a rotational speed decelerated from an input rotational speed by a predetermined reduction ratio.

As shown in FIG. 1 , the gear device 1 of the present embodiment has an outer cylinder portion 2, an inner gear pin 3, a gear carrier 4 as an inner cylinder portion, a main bearing 6, a crankshaft 20, a crankshaft bearing 22, a swing gear 24, and Transmission gear 18 of crankshaft 20 . In addition, in this embodiment, as will be described later, since a plurality of crankshafts 20 are provided, a plurality of transmission gears 18 are provided.

The outer cylinder portion 2 is a structure that can be fixed to one mating member (for example, a base of a robot), and also functions as a case of the gear unit 1 . The outer cylinder portion 2 is formed in a substantially cylindrical shape having an inner peripheral surface. The outer cylinder part 2 is fastened to the base of the robot by bolts or the like.

A large number of inner tooth pins 3 are arranged at equal intervals in the circumferential direction of the inner peripheral surface of the outer cylinder portion 2 . The internally toothed pin 3 functions as an internal tooth that meshes with a tooth portion of a swing gear 24 formed of an externally toothed gear. The number of teeth of the swing gear 24 is several less than the number of the inner tooth pins 3 . In addition, this embodiment employs a plurality of (for example, two) swing gears 24 .

The gear carrier 4 is configured to be fixable on another mating member (for example, a rotating body of a robot). That is, the carrier 4 is fastened to the revolving body of the robot with bolts (not shown) or the like. The carrier 4 is accommodated in the outer tube part 2 in a state of being arranged coaxially with the outer tube part 2 . The carrier 4 is rotatably supported with respect to the outer cylindrical portion 2 by a pair of main bearings 6 provided in an axially divided manner. Therefore, the carrier 4 relatively rotates around the same axis with respect to the outer cylinder portion 2 . When the carrier 4 rotates relative to the outer tube portion 2 , the rotating body of the robot rotates relative to the base.

In addition, although this embodiment exemplifies the case where the carrier 4 is fastened to the revolving body and rotates, and the outer cylinder part 2 is fixed to the base and does not move, the reverse arrangement is also possible. That is, the outer cylinder part 2 may be fastened to a revolving body, and the carrier 4 may be fastened to a base. In this case, since the outer cylinder part 2 rotates relative to the carrier 4, the rotating body of the robot rotates relative to the base.

The gear carrier 4 includes a base portion 32 and an end plate portion 34 . The base portion 32 has a base plate portion 32a disposed near the end of the outer tube portion 2 in the outer tube portion 2 and a plurality of shaft portions 32b extending from the base plate portion 32a toward the end plate portion 34. extend axially. The shaft portion 32b is fastened to the end plate portion 34 by the bolt 5 . Thereby, the base part 32 and the end plate part 34 are integrated. Furthermore, a storage space 33 for housing the swing gear 24 is formed between the base plate portion 32 a and the end plate portion 34 . In addition, a through hole 4 a penetrating through the base plate portion 32 a and the end plate portion 34 in the axial direction is provided at the center portion in the radial direction of the carrier 4 .

A plurality of crankshafts 20 (for example, three in the present embodiment) are provided, and the crankshafts 20 are arranged at equal intervals in the circumferential direction of the carrier 4 . Each crankshaft 20 is rotatably supported by the carrier 4 via a pair of crank bearings 22 , and is arranged in a posture parallel to the rotation axis of the carrier 4 in this state.

The crankshaft 20 has a shaft main body 20c and a plurality of (two in this embodiment) eccentric portions 20a integrally formed with the shaft main body 20c. The plurality of eccentric portions 20a are arranged along the axial direction at positions between the pair of journal portions 20d on which the crank bearings 22 are mounted, respectively. Each eccentric portion 20a is formed in a columnar shape eccentric from the axis of the shaft main body 20c by a predetermined amount of eccentricity. In addition, the eccentric portions 20a are formed on the crankshaft 20 so as to have a predetermined angle of phase difference from each other. In addition, one or three or more eccentric parts 20a may be provided.

The rocking gear 24 is attached to each eccentric part 20a of the crankshaft 20 via the roller bearing 28a, respectively. The diameter of the swing gear 24 is formed slightly smaller than the inner diameter of the outer cylinder part 2 . The swing gear 24 is coupled with the rotation of the eccentric portion 20 a when the crankshaft 20 rotates, and swings and rotates while its teeth mesh with the internal tooth pins 3 on the inner surface of the outer cylinder portion 2 .

The swing gear 24 has a central portion through hole 24b, a plurality of eccentric portion through holes 24c, and a plurality of shaft portion through holes 24d. The center through hole 24b is formed in the radial center of the swing gear 24 . The central through-hole 24b may be omitted.

The eccentric portion through-holes 24 c are provided around the center portion through-hole 24 b at equal intervals in the circumferential direction in the swing gear 24 . The eccentric portion 20 a of each crankshaft 20 passes through each eccentric portion through-hole 24 c in a state where the roller bearing 28 a is attached.

The shaft through-holes 24 d are provided around the center through-hole 24 b at equal intervals in the circumferential direction in the swing gear 24 . Each shaft portion through-hole 24d is formed at a position between the adjacent eccentric portion through-holes 24c in the circumferential direction. Each shaft portion 32b of the carrier 4 penetrates each shaft portion through-hole 24d with play.

The end portion of the crankshaft 20 on the side of the base plate portion 32 a is formed as a journal portion 20 d on which one crank bearing 22 is attached. On the other hand, the end portion of the crankshaft 20 on the side of the end plate portion 34 is formed as an extension portion 20e extending from the other journal portion 20d on which the other crankshaft bearing 22 is attached. That is, the shaft body 20c of the crankshaft 20 has a pair of journal portions 20d and an extension portion 20e.

In the present embodiment, the extension portion 20 e protrudes outward from the carrier 4 in the axial direction of the carrier 4 . However, the extension part 20e is not limited to the manner in which the extension part 20e protrudes to the outside of the carrier 4, and the extension part 20e may be accommodated in the range of the carrier 4 in the axial direction if the transmission gear 18 does not interfere with the carrier 4. way within.

The transmission gear 18 is attached to the extension part 20e. An inner hole 18a is formed in the transmission gear 18, and the transmission gear 18 is fixed to the extension part 20e in a state where the extension part 20e is inserted into the inner hole 18a.

The transmission gear 18 has a gear main body 18c having external teeth 18b and a protrusion 18d protruding from the gear main body 18c in the axial direction. The gear main body 18c is formed in a disc shape, and external teeth 18b are formed on the outer peripheral portion of the gear main body 18c. The protruding portion 18d is formed in a cylindrical shape concentric with the gear main body 18c so as to protrude from one surface of the gear main body 18c. Furthermore, the inner hole 18a is formed so as to penetrate the transmission gear 18 from the gear main body 18c to the protruding portion 18d. The external teeth 18b of the transmission gear 18 mesh with an input gear not shown in the figure. The transmission gear 18 is rotated by the driving force received from the input gear. The transmission gear 18 transmits the drive force received from the input gear to the crankshaft 20 .

Here, the attachment structure of the transmission gear 18 to the crankshaft 20 will be specifically described.

Also, as shown in FIG. 2, an extension portion 20e that is one end portion of the crankshaft 20 (or the shaft main body 20c) is splined. Thereby, the convex key part 38 which has the several recessed part 38a lined up in the circumferential direction is formed in the extension part 20e. That is, on the outer peripheral surface of the extension portion 20e, a plurality of recesses 38a extending in the axial direction of the crankshaft 20 (or the shaft main body 20c) are formed at intervals in the circumferential direction. Each concave portion 38a is formed by extending a predetermined length from the end surface of the extension portion 20e (or the end surface of the crankshaft 20 or the end surface of the shaft main body 20c).

A slope 38b is formed on the bottom surface of the inner portion (the portion opposite to the end surface of the extension portion 20e) of the axially recessed portion 38a so as to gradually become shallower inward in the axial direction. In other words, the slope 38b slopes outward in the radial direction of the shaft main body 20c as it goes toward the inner side of the convex key portion 38 (towards a direction away from the end surface; toward the left side in FIG. 2 ). As the inclined surface 38b, for example, a hob upward chamfering portion generated when the extension portion 20e is cut by a cutting machine having a hob for spline machining can be used.

In addition, the method of forming the slope 38b is not particularly limited, and other forming methods may be used to form the slope 38b at the bottom of the concave portion 38a. In addition, the structure which omits the slope 38b is also possible. In this case, the depth of the recessed portion 38a may be substantially constant in the axial direction, and the inner end portion of the recessed portion 38a may be substantially vertically erected.

Part of the outer surface of the portion formed as the convex portion 38c between the adjacent concave portions 38a, 38a in the extension portion 20e is cut away. For this reason, in the convex portion 38c, the portion on the end portion side of the extension portion 20e is one step lower than the portion on the inner side in the axial direction. And, the portion on the lower end side of the outer surface is not in close contact with the inner peripheral surface of the inner hole 18a of the transmission gear 18, but a gap is formed between the inner peripheral surface of the inner hole 18a and the outer surface of the extension portion 20e. A little gap. This gap is formed at least in the range including the portion corresponding to the gear main body 18c in the inner hole 18a.

In addition, although a one-stage lower portion is formed on the convex portion 38c, it is not necessary to have a step. It does not matter if there is no step, or, contrary to the present embodiment, the outer peripheral surface 20f of the crankshaft 20 may be formed one step lower in the axial direction than the end portion side of the extension portion 20e.

The inner peripheral surface of the part located in the gear main body 18c in the inner hole 18a of the transmission gear 18 is given a spline cutting process. As a result, the concave key portion 40 having the plurality of convex portions 40 a arranged in the circumferential direction is formed on the inner peripheral surface of the portion of the inner hole 18 a. That is, a plurality of protrusions 40 a extending in the axial direction (or thickness direction) of the transmission gear 18 are formed at intervals in the circumferential direction on the inner peripheral surface of the inner hole 18 a. Each convex portion 40 a is formed in a shape matching the concave portion 38 a of the convex key portion 38 . Also, the convex portion 40 a of the concave key portion 40 is inserted into the concave portion 38 a of the convex key portion 38 . In this state, the transfer gear 18 cannot rotate around the axis of the crankshaft 20, and displacement in the direction of rotation around the axis is restricted. That is, the convex portion 40 a of the key and concave portion 40 functions as a locking portion that locks the transmission gear 18 with respect to the crankshaft 20 in the rotational direction of the crankshaft 20 .

The inner peripheral surface 18e of the inner hole 18a of the transmission gear 18 located inside the protruding portion 18d is in close contact with the outer peripheral surface 20f of the axially inner portion of the extension portion 20e. That is, the extension portion 20e is press-fitted into the inner hole 18a of the transmission gear 18 in such a manner as to be caught at the protruding portion 18d. Accordingly, displacement of the transmission gear 18 in the axial direction and in the rotational direction with respect to the crankshaft 20 is restricted. In the inner hole 18 a of the transmission gear 18 , unlike the portion where the crankshaft 20 is press-fitted to be in close contact with the outer peripheral surface 20 f of the crankshaft 20 , a lock for restricting the rotation of the transmission gear 18 in the rotation direction of the crankshaft 20 is provided. part (convex part 40a).

In addition, since a slight gap is formed between the end portion side of the extension part 20e and the inner peripheral surface 18e of the inner hole 18a, when the extension part 20e is pressed into the inner hole 18a, it can be pushed with a relatively weak force. into the bore 18a.

The transmission gear 18 is attached to the crankshaft 20 in a state where the end surface of the extension portion 20 e is substantially flush with one surface of the transmission gear 18 . That is, when pressing in, by abutting against the one surface of the transmission gear 18 with a jig other than the one shown in the figure in the form of a flat plate, it is possible to prevent the top end of the crankshaft 20 (extended portion 20e) from protruding from the inner hole 18a. . In doing so, the axial positioning of the transmission gear 18 can be performed.

In addition, although the edge on the front end side of the crankshaft 20 (that is, the edge of the convex portion 38 c of the key portion 38 ) is chamfered in the present embodiment, it is not limited thereto, and may not be chamfered.

Next, the operation of the gear device 1 according to the present embodiment will be described.

When each transmission gear 18 is driven by an input gear not shown in the figure, each crankshaft 20 rotates about its own axis. That is, driving force for rotating the crankshaft 20 is input to the transmission gear 18 . Then, the eccentric portion 20 a of the crankshaft 20 rotates eccentrically with the rotation of each crankshaft 20 . Thereby, the swing gear 24 swings and rotates while meshing with the inner tooth pin 3 on the inner surface of the outer cylinder part 2 in conjunction with the eccentric rotation of the eccentric part 20 a. In the present embodiment, since the outer cylinder part 2 is fixed on the base and does not move, the gear holder 4 rotates around the axis by the swinging rotation of the swinging gear 24 . As a result, the carrier 4 and the revolving body rotate relative to the outer cylinder portion 2 and the base at a rotational speed obtained by decelerating the input rotation.

As described above, in the present embodiment, when the transmission gear 18 rotates to rotate the crankshaft 20 , the swing gear 24 swings and rotates in conjunction with the rotation of the eccentric portion 20 a. At this time, since the swing gear 24 swings and rotates while its outer teeth mesh with the inner tooth pins 3 of the outer cylinder 2 , relative rotation occurs between the gear holder 4 and the outer cylinder 2 in conjunction with this. At this time, the transmission gear 18 does not shake relative to the crankshaft 20 . That is, by pressing the crankshaft 20 into the inner hole 18 a of the transmission gear 18 , the displacement of the transmission gear 18 relative to the crankshaft 20 is restricted. For this reason, the transmission gear 18 does not rattle relative to the crankshaft 20 . Therefore, it is possible to suppress abrasion of the portion of the transmission gear 18 in contact with the crankshaft 20 , and also to suppress vibration of the transmission gear 18 . In addition, since it is not necessary to install a stop ring for restricting the axial movement of the transmission gear 18 on the crankshaft 20 , it is not necessary to protrude the crankshaft 20 from the transmission gear 18 . For this reason, the axial length of the gear unit 1 can be shortened by a corresponding amount.

In addition, in this embodiment, the transmission gear 18 is fixed relative to the crankshaft 20 by press-fitting the crankshaft 20 into the inner hole 18a of the transmission gear 18, and the portion where the crankshaft 20 is in close contact with the outer peripheral surface 20f of the crankshaft 20 by press-fitting At other locations, a convex portion 40 a for locking the transmission gear 18 with respect to the crankshaft 20 in the rotational direction is formed in the inner hole 18 a of the transmission gear 18 . For this reason, even if a torque for transmitting a driving force from the transmission gear 18 to the crankshaft 20 is generated, it is possible to prevent a situation in which the transmission gear 18 is displaced in the rotational direction with respect to the crankshaft 20 . Therefore, irrespective of whether the crankshaft 20 is pressed into the inner hole 18a of the transmission gear 18, it is possible to more reliably prevent the transmission gear 18 from being rotated in the rotational direction due to the action of the rotational torque.

Moreover, in this embodiment, the transmission gear 18 has the gear main body 18c and the protrusion part 18d, and the convex part 40a is formed in the part located in the gear main body 18c in the inner hole 18a. Therefore, when the external teeth 18b of the gear main body 18c receive a torque that rotates the transmission gear 18 , the convex portion 40a located in the gear main body 18c in the inner hole 18a is engaged with the crankshaft 20 . Therefore, the force which rotates the transmission gear 18 by a rotation torque can be reliably received by the convex part 40a. In addition, since the crankshaft 20 is press-fitted into at least the protruding portion 18d of the inner hole 18a, the area of the portion that is in close contact with the outer peripheral surface 20f of the crankshaft 20 by the press-fitting can be enlarged. Therefore, the effect of preventing rattling by pressing can be further manifested.

In addition, this invention is not limited to the said embodiment, Various changes, improvements, etc. are possible in the range which does not deviate from the summary. For example, in the embodiment described above, when assembling the transmission gear 18 to the crankshaft 20 , the transmission gear 18 is positioned at a predetermined position on the crankshaft 20 using a jig (not shown). Instead of such a configuration, as shown in FIG. 3 , a positioning member 42 for positioning the transmission gear 18 at a predetermined position on the crankshaft 20 may be provided.

Specifically, the positioning member 42 is fitted outside the extension portion 20 e of the crankshaft 20 and then sandwiched between one crankshaft bearing 22 and the transmission gear 18 . Since the crank bearing 22 is in contact with the washer 44 provided at a position adjacent to the eccentric portion 20a, the position of the crank bearing 22 is determined at a predetermined position. In addition, the positioning member 42 abutting on the crank bearing 22 is also fixed at a predetermined position, so the transmission gear 18 is fixed at a predetermined position by abutting against the positioning member 42 . Therefore, the axial position of the transfer gear 18 relative to the crankshaft 20 can be accurately positioned.

In addition, the transmission gear 18 may be positioned at a predetermined position with respect to the crankshaft 20 by the concave key portion 40 formed in the inner hole 18 a of the transmission gear 18 and the convex key portion 38 of the crankshaft 20 . As described above, the bottom surface of the inner portion of the recessed portion 38a of the extension portion 20e (the portion opposite to the end surface of the extension portion 20e) forms the slope 38b so as to gradually become shallower inward in the axial direction. For this reason, as shown in FIG. 4, since the end of the convex portion 40a of the concave key portion 40 abuts against the slope 38b of the bottom surface of the concave portion 38a of the convex key portion 38, the transmission gear 18 is fixed at a predetermined position with respect to the crankshaft 20. Location. That is to say, the so-called wedge effect can be obtained by forcing the inclined surface 38b onto the convex portion 40a of the concave key portion 40 to generate a large frictional force at its contact surface, so that the transmission gear 18 bites into the crankshaft The state of 20 is bound to the crankshaft 20 .

In this form, the transmission gear 18 is bound to the crankshaft 20 by fitting the convex portion 40a of the concave key portion 40 into the slope 38b formed in the concave portion 38a of the convex key portion 38 . Therefore, axial positioning of the transmission gear 18 can be performed by using the inclined surface 38 b formed in the concave portion 38 a of the convex key portion 38 .

In the above-described embodiment, the configuration in which the convex portion 40a of the key-and-derivative portion 40 is provided as the locking portion that locks the transmission gear 18 with respect to the crankshaft 20 in the rotational direction has been described. Instead of such a structure, a key groove may be formed in the inner hole 18a of the transmission gear 18, and the convex portion 38c of the convex key portion 38 may be engaged with the key groove. In this case, the side surfaces of the key groove function as locking portions.

In the embodiment described above, the crankshaft 20 has the extension portion 20e protruding toward the end plate portion 34, and the transmission gear 18 is disposed on the end plate portion 34 side. Instead of such a configuration, a configuration may be employed in which the extension portion 20e of the crankshaft 20 is disposed on the side of the base plate portion 32a, and the transmission gear 18 is disposed on the side of the base plate portion 32a.

In the above-mentioned embodiment, the structure provided with the two swing gears 24 and 24 was adopted, but it is not limited to this. For example, one swing gear 24 may be provided, or three or more swing gears 24 may be provided.

In the above-mentioned embodiment, the structure in which the plurality of crankshafts 20 are arranged around the central through-hole 4 a is adopted, but the present invention is not limited thereto. For example, a center crank type in which one crankshaft 20 is arranged at the center of the carrier 4 may be used.

Here, the above-mentioned embodiment will be summarized.

(1) In the above-described embodiment, when the crankshaft rotates due to the rotation of the transmission gear, the swing gear performs swing rotation in conjunction with the rotation of the eccentric portion. At this time, since the oscillating gear oscillatingly rotates while its tooth portion meshes with the inner teeth of the outer cylinder portion, relative rotation occurs between the inner cylinder portion and the outer cylinder portion in conjunction with this. At this time, the transmission gear will not shake relative to the crankshaft. That is, by pressing the crankshaft into the inner hole of the transmission gear, the displacement of the transmission gear relative to the crankshaft is limited. For this reason, the transmission gear does not play with respect to the crankshaft. Therefore, it is possible to suppress wear of the transmission gear at the portion in contact with the crankshaft, and furthermore, it is possible to suppress vibration of the transmission gear. In addition, since it is not necessary to install a stop ring for restricting the axial movement of the transmission gear on the crankshaft, it is not necessary to protrude the crankshaft from the transmission gear. For this reason, the axial length of the gear unit can be shortened by a corresponding amount.

(2) In other than the portion of the inner hole that is in close contact with the outer surface of the crankshaft by press-fitting, there may be formed a groove for rotating the transmission gear with respect to the crankshaft in the direction of rotation. Locking locking part.

In this form, the transmission gear is fixed relative to the crankshaft by pressing the crankshaft into the inner hole of the transmission gear. A locking portion that locks the transmission gear with respect to the crankshaft in the rotational direction is formed. For this reason, even if a torque of driving force is transmitted from the transmission gear to the crankshaft, it is possible to reliably prevent the transmission gear from being displaced in the rotational direction with respect to the crankshaft. Therefore, irrespective of whether or not the crankshaft is pressed into the inner hole of the transmission gear, it is possible to more reliably avoid a situation in which the transmission gear is rotated in the rotational direction by receiving the rotational torque.

(3) The transmission gear may have a gear main body and a protrusion, the gear main body has external teeth, and the protrusion protrudes from the gear main body in the axial direction. Alternatively, the crankshaft may be press-fitted into the inner hole at least at a portion located at the protruding portion. It is also possible that the locking portion is formed in a part of the inner hole located on the gear main body.

In this form, when a torque that rotates the transmission gear is received on the outer teeth of the gear body, the locking portion located in the gear body in the inner hole is locked by the crankshaft. Therefore, the force that rotates the transmission gear due to the rotational torque can be reliably received by the locking portion. In addition, since the crankshaft is press-fitted into at least the protruding portion of the inner hole, it is possible to increase the area of the portion that is in close contact with the outer surface of the crankshaft by press-fitting. Therefore, the effect of preventing rattling by pressing can be further manifested.

(4) A crankshaft bearing may be externally fitted on the crankshaft. In this case, a positioning member interposed between the transmission gear and the crank bearing may be provided.

In this form, the position of the transmission gear with respect to the crankshaft is determined by bringing the transmission gear into contact with the positioning member. Therefore, the axial position of the transfer gear relative to the crankshaft can be accurately positioned.

(5) A convex key portion for spline coupling the transmission gear may be formed at an end portion of the crankshaft. Alternatively, a concave key portion having a shape corresponding to the shape of the convex key portion may be formed in the inner hole. The convex part of the said concave key part may be fitted with the slope formed in the concave part of the said convex key part.

In this form, the transmission gear is bound to the crankshaft by fitting the convex portion of the concave key portion with the slope formed in the concave portion of the convex key portion. Therefore, the axial positioning of the transmission gear can be performed using the slope formed in the concave portion of the convex key portion.

As described above, according to the above-mentioned embodiment, the eccentric oscillating gear unit can suppress the length in the axial direction and eliminate the rattling of the transmission gear with respect to the crankshaft.

Claims (5)

1. an Eccentrically swinging gear device, wherein, it comprises:

Bent axle, this bent axle has eccentric part;

Wobble gear, this wobble gear has teeth portion and links with described eccentric part;

Outer cylindrical portion, this outer cylindrical portion has the internal tooth be meshed with the described teeth portion of described wobble gear;

Inner cylinder portion, described crankshaft support is rotatable by this inner cylinder portion;

Main bearing, this main bearing allows the relative rotation between described outer cylindrical portion with described inner cylinder portion; And

Transmit gear, this transmission gear has endoporus,

Described bent axle is pressed into the described endoporus of described transmission gear, to limit the displacement of described transmission gear relative to described bent axle.

2. Eccentrically swinging gear device as described in claim 1, wherein,

Position beyond the position closely sealed with the outer surface of described bent axle because of press-in in described endoporus, is formed for by engaging portion locking in a rotational direction relative to described bent axle for described transmission gear.

3. Eccentrically swinging gear device as described in claim 2, wherein,

Described transmission gear has gear body and protuberance, and described gear body has external tooth, and described protuberance is axially given prominence to from described gear body,

Described bent axle is pressed into the position being at least positioned at described protuberance in described endoporus,

Described engaging portion is formed in the position being positioned at described gear body in described endoporus.

4. as the Eccentrically swinging gear device in claims 1 to 3 as described in any one, wherein,

Be nested with crankshaft bearing outside described bent axle, and be provided with the align member be sandwiched between described transmission gear and described crankshaft bearing.

5. as the Eccentrically swinging gear device in claims 1 to 3 as described in any one, wherein,

The end of described bent axle is formed with the convex key portion carrying out spline with described transmission gear and be combined,

The recessed key portion that shape is corresponding with the shape in described convex key portion is formed in described endoporus,

The protuberance in described recessed key portion and the inclined plane embedding of recess being formed at described convex key portion.