WO2013061533A1

WO2013061533A1 - Gear transmission device

Info

Publication number: WO2013061533A1
Application number: PCT/JP2012/006577
Authority: WO
Inventors: 義昭牧添; 隆成瀬
Original assignee: ナブテスコ株式会社
Priority date: 2011-10-25
Filing date: 2012-10-15
Publication date: 2013-05-02
Also published as: JP2013092179A; TW201335512A; TWI560380B; DE112012004442T5; JP5798882B2; KR101947216B1; KR20140084239A; DE112012004442B4; CN103890452A; CN103890452B

Abstract

First outer teeth (14a) each have a first machined section (142) at one of the ends thereof, and the tooth surface of the first machined section (142) is machined so that the tooth surface extends inward in the radial direction as the tooth surface extends toward an end thereof in the axial direction. Second teeth (16a) each have a machined section (162) at one of the ends thereof, and the tooth surface of the second machined section (162) is machined so that the tooth surface extends inward in the radial direction as the tooth surface extends toward an end thereof in the axial direction. Inner tooth pins (3) are each provided with: a first reduced diameter section (31) provided at the portion of the inner tooth pin (3) which corresponds in the radial direction to an end of each of the first outer teeth (14a), the end being on the side on which the first machined section (142) is not provided; and a second reduced diameter section (32) provided at the portion of the inner tooth pin (3) which corresponds in the radial direction to an end of each of the second outer teeth (16a), the end being on the side on which the second machined section (162) is not provided.

Description

Gear transmission

The present invention relates to a gear transmission.

Conventionally, an eccentric oscillating type that obtains an output rotation that is decelerated with respect to the input rotational speed by oscillating and rotating an external gear that meshes with an internal tooth pin of an internal gear in conjunction with the eccentric rotation of the eccentric part of the crankshaft. A gear transmission is known (see, for example, Patent Document 1).

The gear transmission described in Patent Document 1 is provided with a plurality of internal teeth pins that mesh with two external gears. Each internal tooth pin has the 1st meshing part, the 2nd meshing part, and the connection part which connects these. Both ends in the axial direction of each meshing portion are subjected to crowning processing (FIGS. 3 and 6 of Patent Document 1). Thereby, the edge stress which arises between the tooth surface of each external gear and the outer peripheral surface of the axial direction both ends in each meshing part of an internal tooth pin is reduced. Moreover, in FIG. 7 of patent document 1, not only an internal tooth pin but the tooth surface of the both ends of each external gear is also crowned. Thereby, the edge stress which arises between the tooth surface of the both ends of each external gear and the outer peripheral surface of the axial direction both ends of each meshing part of an internal tooth pin is further reduced.

However, in the gear transmission shown in FIG. 3 and FIG. 6 of Patent Document 1, both ends of the first meshing portion of each internal tooth pin are crowned, and both ends of the second meshing portion are crowned. Since a process in which the meshing portion is connected by the connecting portion is necessary, there is a problem that the cost is increased. In addition to this, when both ends of each external gear are subjected to crowning as shown in FIG. 7 of Patent Document 1, the number of man-hours required for crowning is further increased and the cost is increased.

JP 2009-293650 A

An object of the present invention is to provide a gear transmission that can suppress an increase in cost while suppressing generation of edge stress between an external gear and an internal tooth pin.

The gear transmission according to the present invention is
An outer cylinder having an inner peripheral surface in which a plurality of pin grooves extending in the axial direction are provided at predetermined intervals in the circumferential direction;
A plurality of internal teeth pins arranged in each of the plurality of pin grooves;
A crankshaft having a first eccentric portion and a second eccentric portion arranged side by side in the axial direction with a predetermined phase difference from each other, and provided to be rotatable around the axis in the outer cylinder;
It has an outer peripheral surface provided with first external teeth, is attached to the first eccentric portion, and swings in conjunction with the eccentric rotation of the first eccentric portion while the first external teeth mesh with the internal tooth pin. A rotating first external gear;
It has an outer peripheral surface provided with second external teeth, is attached to the second eccentric portion, and swings in conjunction with the eccentric rotation of the second eccentric portion while the second external teeth mesh with the internal tooth pin. A rotating second external gear,
A carrier that rotates relative to the outer cylinder by transmitting the swinging rotation of the first external gear and the second external gear.

The first external tooth has a first processed portion at one end in the axial direction. The tooth surface of the first processed portion is processed so as to be located radially inward as it goes toward the axial end of the tooth surface. The second external tooth has a second processed portion at one end portion in the axial direction. The tooth surface of the second processed portion is processed so as to be positioned radially inward as it goes toward the axial end of the tooth surface.

Each internal tooth pin has a first reduced diameter portion and a second reduced diameter portion. The first reduced diameter portion is processed so that the diameter of the portion opposed to the end portion of the first external tooth on the side where the first processed portion is not provided decreases in the axial direction. ing. The second reduced diameter portion is processed so that the diameter of the portion opposed to the end portion of the second external tooth on the side where the second processed portion is not provided decreases in the axial direction. ing.

It is sectional drawing which shows the gear transmission which concerns on 1st Embodiment of this invention. FIG. 2 is a sectional view taken along line II-II in FIG. It is an expanded sectional view which shows the structure of the meshing part vicinity of the internal gear pin and external gear in the gear transmission shown in FIG. It is the expansion perspective view for demonstrating the structure of the meshing part vicinity of the internal gear pin and external gear in the gear transmission shown in FIG. 1, and is the figure which fractured | ruptured a part of the said structure. The gear transmission which concerns on 2nd Embodiment of this invention is shown, It is an expanded sectional view which shows the structure of the meshing part vicinity of an internal gear pin and an external gear.

Hereinafter, the gear transmission 1 according to the embodiment of the present invention will be described in detail with reference to the drawings. The gear transmission 1 is applied as a speed reducer to, for example, a turning unit such as a turning drum or arm joint of a robot, or a turning unit of various machine tools.

<First Embodiment>
(Whole structure of gear transmission)
In the gear transmission 1 according to the first embodiment, the first external gear 14 swings and rotates in conjunction with the first eccentric portion 10a of the crankshaft 10, and in conjunction with the second eccentric portion 10b of the crankshaft 10. By rotating the second external gear 16 in an oscillating manner, an output rotation decelerated from the input rotational speed is obtained.

As shown in FIG. 1, the gear transmission 1 includes an outer cylinder 2, a large number of internal tooth pins 3, a carrier 4, an input shaft 8, a plurality of (for example, three) crankshafts 10, and a first outer shaft. The tooth gear 14, the second external gear 16, and a plurality of (for example, three) transmission gears 20 are provided.

As shown in FIG. 2, the outer cylinder 2 constitutes the outer surface of the gear transmission 1 and has a substantially cylindrical shape. A large number of pin grooves 2 b are formed on the inner peripheral surface of the outer cylinder 2. Each pin groove 2b extends in the axial direction of the outer cylinder 2, and has a semicircular cross-sectional shape in a cross section orthogonal to the axial direction. These pin grooves 2 b are arranged at equal intervals in the circumferential direction on the inner peripheral surface of the outer cylinder 2.

Each internal tooth pin 3 is attached to a corresponding pin groove 2b. Specifically, each internal tooth pin 3 is fitted in the corresponding pin groove 2b. The axial direction of each internal tooth pin 3 extends along the axial direction of the outer cylinder 2. Thereby, the many internal tooth pins 3 are arranged at equal intervals along the circumferential direction of the outer cylinder 2. In the pin groove 2b, each internal tooth pin 3 can rotate around its axis. The first external gear 14 and the second external gear 16 mesh with these internal teeth pins 3. The detailed structure of the internal tooth pin 3 will be described later.

As shown in FIG. 1, the carrier 4 is accommodated in the outer cylinder 2 in a state of being arranged coaxially with the outer cylinder 2. The carrier 4 rotates relative to the outer cylinder 2 around the same axis. Specifically, the carrier 4 is supported so as to be rotatable relative to the outer cylinder 2 by a pair of carrier bearings 6 that are provided apart from each other in the axial direction. In the present embodiment, the carrier 4 includes a base portion 4a, an end plate portion 4b, and a plurality of (for example, three) shaft portions 4c. However, the configuration is not limited to this.

The base portion 4 a is disposed on the one end side in the axial direction of the outer cylinder 2 in the outer cylinder 2. A circular through hole 4d is provided in the central portion of the base portion 4a in the radial direction. Around the through hole 4d, a plurality of (for example, three) crankshaft mounting holes 4e (hereinafter simply referred to as mounting holes 4e) are provided at equal intervals in the circumferential direction.

The end plate portion 4 b is provided to be spaced apart from the base portion 4 a in the axial direction, and is disposed inside the outer cylinder 2 on the other end side in the axial direction of the outer cylinder 2. A through hole 4f is provided at the radial center of the end plate portion 4b. Around the through hole 4f, a plurality of (for example, three) crankshaft mounting holes 4g (hereinafter simply referred to as mounting holes 4g) are provided at positions corresponding to the plurality of mounting holes 4e of the base portion 4a. In the outer cylinder 2, a closed space surrounded by both inner surfaces of the end plate portion 4 b and the base portion 4 a facing each other and the inner peripheral surface of the outer cylinder 2 is formed.

The three shaft portions 4c are integrally provided on the base portion 4a and linearly extend from the base portion 4a to the end plate portion 4b side. The three shaft portions 4c are arranged at equal intervals in the circumferential direction (see FIG. 2). Each shaft portion 4c is fastened to the end plate portion 4b by a bolt 4h (see FIG. 1). Thereby, the base part 4a, the shaft part 4c, and the end plate part 4b are integrated.

The input shaft 8 functions as an input unit to which rotation is input by a drive motor (not shown). The input shaft 8 is inserted into the through hole 4f of the end plate portion 4b and the through hole 4d of the base portion 4a. The input shaft 8 is arranged such that its axis coincides with the axes of the outer cylinder 2 and the carrier 4. The input shaft 8 rotates around that axis. An input gear 8 a is provided on the outer peripheral surface of the distal end portion of the input shaft 8.

The three crankshafts 10 are arranged at equal intervals around the input shaft 8 in the outer cylinder 2 (see FIG. 2). Each crankshaft 10 is attached to the corresponding attachment hole 4e of the base portion 4a and the attachment hole 4g of the end plate portion 4b (see FIG. 1). Specifically, the axially inner portion of each crankshaft 10 by a predetermined length from one axial end is mounted in the mounting hole 4e of the base portion 4a via the first crank bearing 12a. On the other hand, the other axial end portion of each crankshaft 10 is mounted in the mounting hole 4g of the end plate portion 4b via the second crank bearing 12b. Each crankshaft 10 is supported by both crank

bearings

12a and 12b so as to be rotatable about the axis with respect to the carrier 4.

Each crankshaft 10 has a first eccentric portion 10a and a second eccentric portion 10b arranged in the axial direction between portions supported by both crank

bearings

12a and 12b. Each of the first eccentric portion 10a and the second eccentric portion 10b has a cylindrical shape. The first eccentric portion 10a and the second eccentric portion 10b are each eccentric from the axis of the crankshaft 10 by a predetermined amount of eccentricity, and are arranged so as to have a phase difference of a predetermined angle. In addition, a fitted portion 10c to which the transmission gear 20 is attached is provided at one end of the crankshaft 10, that is, a portion on the outer side in the axial direction from a portion attached in the attachment hole 4e of the base 4a.

As shown in FIGS. 1 and 2, the first external gear 14 is disposed in the closed space in the outer cylinder 2. The first external gear 14 is attached to the first eccentric portion 10a of each crankshaft 10 via a first roller bearing 18a. When each crankshaft 10 rotates and the first eccentric portion 10a rotates eccentrically, the first external gear 14 swings and rotates while meshing with the internal pin 3 in conjunction with the eccentric rotation.

The first external gear 14 has a size slightly smaller than the inner diameter of the outer cylinder 2. In the present embodiment, the first external gear 14 includes first external teeth 14a, a central through hole 14b, a plurality of (for example, three) first eccentric portion insertion holes 14c, and a plurality of (for example, three). It has a shaft portion insertion hole 14d. However, the configuration is not limited to this.

As shown in FIG. 2, the central through hole 14 b is provided in the radial center of the first external gear 14. The input shaft 8 is inserted into the central through hole 14b with play.

The three first eccentric portion insertion holes 14c are provided at equal intervals in the circumferential direction around the central through hole 14b in the first external gear 14. The first eccentric portion 10a of the corresponding crankshaft 10 is inserted into each first eccentric portion insertion hole 14c with the first roller bearing 18a interposed.

The three shaft part insertion holes 14d are provided at equal intervals in the circumferential direction around the central part through hole 14b in the first external gear 14. Each shaft portion insertion hole 14d is disposed at a position between the three first eccentric portion insertion holes 14c in the circumferential direction. The corresponding shaft portion 4c is inserted into each shaft portion insertion hole 14d with play. The detailed structure of the first external teeth 14a will be described later.

The second external gear 16 is disposed in the closed space in the outer cylinder 2. The second external gear 16 is attached to the second eccentric portion 10b of each crankshaft 10 via a second roller bearing 18b. The first external gear 14 and the second external gear 16 are provided side by side in the axial direction corresponding to the arrangement of the first eccentric portion 10a and the second eccentric portion 10b. When each crankshaft 10 rotates and the second eccentric portion 10b rotates eccentrically, the second external gear 16 rotates and rotates while meshing with the internal tooth pin 3 in conjunction with the eccentric rotation.

The second external gear 16 has a size slightly smaller than the inner diameter of the outer cylinder 2. In the present embodiment, the second external gear 16 includes the second external teeth 16a, the central through hole 16b, a plurality of (for example, three) second eccentric portion insertion holes 16c, and a plurality of (for example, three) shaft portion insertions. It has a hole 16d. However, the configuration is not limited to this. These have the same structure as the first external teeth 14a, the central through hole 14b, the plurality of first eccentric portion insertion holes 14c, and the plurality of shaft portion insertion holes 14d of the first external gear 14. The second eccentric portion 10b of the corresponding crankshaft 10 is inserted in each second eccentric portion insertion hole 16c with the second roller bearing 18b interposed. The detailed structure of the second external teeth 16a will be described later.

Each transmission gear 20 transmits the rotation of the input gear 8a to the corresponding crankshaft 10. Each transmission gear 20 is externally fitted to a fitted portion 10 c provided at one end of the corresponding crankshaft 10. Each transmission gear 20 rotates integrally with the crankshaft 10 about the same axis as the rotation axis of the crankshaft 10. Each transmission gear 20 has external teeth 20a that mesh with the input gear 8a.

(Internal tooth pin structure)
As shown in FIGS. 2 to 4, each internal tooth pin 3 has a substantially cylindrical shape. Each internal tooth pin 3 is formed by cutting and / or polishing a single bar-shaped metal material. In the present embodiment, the outer peripheral surface of each internal tooth pin 3 is subjected to crowning by cutting and / or polishing. Thereby, the outer diameter of the axial direction both ends of each internal tooth pin 3 is small compared with the outer diameter of the site | part between these. Specifically, it is as follows.

Each internal tooth pin 3 has a first reduced diameter portion 31 located at one end in the axial direction, a second reduced diameter portion 32 located at the other end in the axial direction, and these reduced diameter portions 31. , 32 and a columnar part (intermediate part) 33. In each internal tooth pin 3, the first reduced diameter portion 31, the columnar portion 33, and the second reduced diameter portion 32 are integrally formed side by side in this order in the axial direction. The first reduced diameter portion 31, the second reduced diameter portion 32, and the columnar portion 33 have a circular cross section orthogonal to the axial direction.

The columnar portion 33 has a cylindrical shape, and the outer diameter thereof is constant in the axial direction. The first reduced diameter portion 31 has a tapered shape. The outer diameter of the first reduced diameter portion 31 is gradually reduced toward one end edge in the axial direction. The second reduced diameter portion 32 has a tapered shape. The outer diameter of the second reduced diameter portion 32 is gradually reduced toward the other end edge in the axial direction. Therefore, in each internal tooth pin 3, the outer diameter of the columnar part 33 is the largest. The outer peripheral surface of the first reduced diameter portion 31 and the outer peripheral surface of the second reduced diameter portion 32 are curved surfaces that are convex outward. The outer peripheral surface of the first reduced diameter portion 31 and the outer peripheral surface of the second reduced diameter portion 32 are smoothly curved toward the respective end edges.

The columnar portion 33 is a portion where the first external gear 14 and the second external gear 16 mesh. Specifically, as shown in FIGS. 3 and 4, the portion of the columnar portion 33 on the first reduced diameter portion 31 side from the vicinity of the center in the axial direction is in relation to the first external teeth 14 a of the first external gear 14. The first external teeth 14a mesh with this portion. On the other hand, the portion of the columnar portion 33 on the second reduced diameter portion 32 side from the vicinity of the center in the axial direction is provided at a position facing the second external teeth 16a of the second external gear 16 in the radial direction. The second external teeth 16a mesh with this part.

The first reduced diameter portion 31 is provided at a position facing the axially outer end portion of the first external tooth 14a in the radial direction. The second reduced diameter portion 32 is provided at a position facing the axially outer end portion of the second external tooth 16a in the radial direction.

(External tooth structure)
As shown in FIG. 2, the first external teeth 14 a are provided on the outer peripheral surface of the first external gear 14. The tooth surface of the first external tooth 14a has a wave shape that is smoothly continuous over the entire circumferential direction in a cross section orthogonal to the axial direction (cross section shown in FIG. 2). In other words, the tooth surface of the first external tooth 14a has a crest located on the radially outer side and a trough located on the radially inner side alternately arranged along the circumferential direction.

Each mountain and each valley have a substantially arc shape in a cross section perpendicular to the axial direction. The plurality of peaks and the plurality of valleys form a smooth curved surface as a whole. Here, the boundary between the ridges and valleys adjacent to each other is the tip (peak) of the ridge located on the outermost side and the bottom of the valley located on the innermost side in the radial direction of the first external gear 14. It is the site | part on the tooth surface located in the middle of this.

The number of teeth of the first external teeth 14a is set slightly smaller than the number of internal tooth pins 3. In the present embodiment, the number of teeth of the first external teeth 14 a is set to be one less than the number of internal tooth pins 3. However, the configuration is not limited to this. The second external teeth 16a have the same structure as the first external teeth 14a described above.

As shown in FIGS. 3 and 4, the first external teeth 14 a mesh with a portion of the internal teeth pin 3 on the first reduced diameter portion 31 side of the columnar portion 33. The second external teeth 16 a mesh with the portion of the columnar portion 33 of the internal tooth pin 3 on the second reduced diameter portion 32 side. The first external teeth 14 a include a first external tooth main body portion 141 and a first processing portion 142. The second external teeth 16 a include a second external tooth main body portion 161 and a second processing portion 162.

The first external tooth main body 141 is a part whose tooth surface is parallel to the axial direction. The first external tooth main body portion 141 extends from the boundary portion with the first processing portion 142 to the edge of the tooth surface opposite to the first processing portion 142 in the axial direction. The first external tooth main body 141 opposes the first reduced diameter portion 31 of the internal tooth pin 3 in the radial direction and opposes a part of the columnar portion 33 of the internal tooth pin 3 in the radial direction. In the axial direction, a part of the first external tooth main body 141 is located on the second external tooth 16 a side with respect to the first reduced diameter portion 31 of the internal tooth pin 3. The axial length of the first external tooth main body 141 is larger than the axial length of the first processed portion 142.

The second external tooth main body 161 is a part whose tooth surface is parallel to the axial direction. The second external tooth main body 161 extends from the boundary portion with the second processed portion 162 to the edge of the tooth surface opposite to the second processed portion 162 in the axial direction. The second external tooth main body 161 is opposed to the second reduced diameter portion 32 of the internal tooth pin 3 in the radial direction, and is opposed to a part of the columnar portion 33 of the internal tooth pin 3 in the radial direction. In the axial direction, a part of the second external tooth main body 161 is located closer to the first external tooth 14 a than the second reduced diameter portion 32 of the internal tooth pin 3. The axial length of the second external tooth main body 161 is larger than the axial length of the second processed portion 162.

The first processing unit 142 and the second processing unit 162 are provided at positions adjacent to each other in the axial direction. The 1st process part 142 and the 2nd process part 162 are each provided in the inner side edge part of the 1st external tooth 14a, and the inner side edge part of the 2nd external tooth 16a. That is, the 1st process part 142 is provided in the edge part by the side of the 2nd external tooth 16a among the both ends of the axial direction in the 1st external tooth 14a. The 2nd process part 162 is provided in the edge part by the side of the 1st external tooth 14a among the axial direction both ends of the 2nd external tooth 16a.

The 1st process part 142 is a site | part processed into the curved shape so that the tooth surface may be located inside radial direction as it goes to the 2nd external tooth 16a side of an axial direction. That is, the tooth surface of the first processed portion 142 is processed so as to be positioned radially inward as it goes toward the axial end of the tooth surface (the edge of the tooth surface). In this embodiment, the 1st process part 142 is provided over the whole circumferential direction of the 1st external tooth 14a. That is, the 1st process part 142 is provided in all the peak parts and trough parts located in a line with the circumferential direction. The first processed portion 142 faces the part of the columnar portion 33 of the internal tooth pin 3 in the radial direction of the internal tooth pin 3.

The 2nd process part 162 is a site | part processed into the curved shape so that the tooth surface may be located in a radial inside as it goes to the 1st external tooth 14a side of an axial direction. That is, the tooth surface of the second processed portion 162 is processed so as to be positioned radially inward as it goes toward the axial end of the tooth surface (the edge of the tooth surface). In this embodiment, the 2nd process part 162 is provided over the whole circumferential direction of the 2nd external tooth 16a. That is, the 2nd process part 162 is provided in all the crests and troughs located in a line with the circumferential direction. The second processed portion 162 faces the part of the columnar portion 33 of the internal tooth pin 3 in the radial direction of the internal tooth pin 3.

The first reduced diameter portion 31, the first processed portion 142, and the second processed portion 162 are not opposed to the radial direction of the internal tooth pin 3. The second reduced diameter portion 32, the first processed portion 142, and the second processed portion 162 are not opposed to the radial direction of the internal tooth pin 3.

In the first processing portion 142 and the second processing portion 162, the processing depth in the peak portion and the processing depth in the trough portion may be similar, but are not limited thereto. For example, the processing depth in the peak portion may be larger than the processing depth in the valley portion.

In addition, the front-end | tip (peak) of the peak part in the 1st external tooth 14a protrudes to a radial direction outer side so that the contact to the internal tooth pin 3 may be suppressed at the time of the rocking | fluctuation rotation of the 1st external gear 14. The amount is preferably adjusted. The same applies to the tip of the peak portion of the second external tooth 16a.

(Operation)
Next, the operation of the gear transmission 1 will be described. First, rotation is input to the input shaft 8 of the gear transmission 1 by driving a motor (not shown), for example. As a result, the input gear 8 a rotates together with the input shaft 8. The rotation of the input gear 8 a is transmitted to each crankshaft 10 via each transmission gear 20.

Then, as each crankshaft 10 rotates, the first eccentric portion 10a and the second eccentric portion 10b of each crankshaft 10 rotate eccentrically. Thus, in conjunction with the eccentric rotation of the first eccentric portion 10a, the first external gear 14 oscillates and rotates while meshing with the portion of the columnar portion 33 of the internal tooth pin 3 on the first reduced diameter portion 31 side. In synchronization with the eccentric rotation of the two eccentric portion 10b, the second external gear 16 swings and rotates while meshing with the portion of the columnar portion 33 of the internal tooth pin 3 on the second reduced diameter portion 32 side. The swing rotation of the first external gear 14 and the second external gear 16 is transmitted to the carrier 4 through each crankshaft 10, and the entire carrier 4 is rotated with respect to the outer cylinder 2 at a speed reduced from the input rotation. Relative rotation.

<Second Embodiment>
FIG. 5 shows the gear transmission 1 according to the second embodiment of the present invention, and is an enlarged cross-sectional view showing the structure in the vicinity of the meshing portion between the internal tooth pin 3 and the

external gears

14 and 16. In the following description, components similar to those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and description thereof is omitted.

As shown in FIG. 5, in the second embodiment, each internal tooth pin 3 includes a first reduced diameter portion 34 and a second reduced diameter portion 35 that are located near the center in the axial direction, and a first reduced diameter portion 34. The first columnar portion 36 is positioned at one outer end portion in the axial direction, and the second columnar portion 37 is positioned at the other outer end portion in the axial direction than the second reduced diameter portion 35.

The first columnar portion 36 has a cylindrical shape, and its outer diameter is constant in the axial direction. The second columnar portion 37 has a cylindrical shape, and the outer diameter thereof is constant in the axial direction. The first reduced diameter portion 34 is processed so as to decrease in diameter from the boundary with the first columnar portion 36 toward the second reduced diameter portion 35 in the axial direction. The second reduced diameter portion 35 is processed so as to reduce the diameter from the boundary with the second columnar portion 37 toward the first reduced diameter portion 34 in the axial direction. The outer peripheral surface of the first reduced diameter portion 34 and the outer peripheral surface of the second reduced diameter portion 35 are curved surfaces that are convex outward. The outer peripheral surface of the first reduced diameter portion 34 and the outer peripheral surface of the second reduced diameter portion 35 are smoothly curved toward each other boundary portion. The outer diameter of each internal tooth pin 3 is the smallest at the boundary between the first reduced diameter portion 34 and the second reduced diameter portion 35.

The first processed portion 142 of the first external tooth 14a is provided at an outer end portion located on one outer side in the axial direction of the first external tooth 14a. The 1st process part 142 is a site | part processed so that the tooth surface may be located in a radial inside as it goes to one outer side of an axial direction. That is, the tooth surface of the first processed portion 142 is processed so as to be positioned radially inward as it goes toward the axial end of the tooth surface (the edge of the tooth surface).

The second processed portion 162 of the second external tooth 16a is provided at the outer end located on the other outer side in the axial direction of the second external tooth 16a. The 2nd process part 162 is a site | part processed so that the tooth surface may be located in a radial inside as it goes to the other outer side of an axial direction. That is, the tooth surface of the second processed portion 162 is processed so as to be positioned radially inward as it goes toward the axial end of the tooth surface (the edge of the tooth surface).

The first reduced diameter portion 34, the first processed portion 142, and the second processed portion 162 are not opposed to the radial direction of the internal tooth pin 3. The second reduced diameter portion 35, the first processed portion 142, and the second processed portion 162 are not opposed to the radial direction of the internal tooth pin 3. The first reduced diameter portion 34 is opposed to the end portion (the inner end portion in the axial direction) of the first outer teeth 14a where the first processed portion 142 is not provided in the radial direction of the inner tooth pin 3. . The second reduced diameter portion 35 is opposed to the end portion (the inner end portion in the axial direction) of the second outer teeth 16a where the second processed portion 162 is not provided in the radial direction of the inner tooth pin 3. .

As described above, in the first and second embodiments, the first external tooth 14a is provided with the first processed portion 142 at one end, and the second external tooth 16a has either one. The 2nd process part 162 is provided in the edge part. Each internal tooth pin 3 has a first reduced diameter portion at a portion that is radially opposed to an end portion where the first processed portion 142 is not provided and an end portion where the second processed portion 162 is not provided. 31 (34) and a second reduced diameter portion 32 (35) are provided. That is, in order to suppress the occurrence of edge stress between the first external teeth 14a and the second external teeth 16a and the internal tooth pins 3, the first external teeth 14a, the second external teeth 16a and the internal tooth pins In 3, the minimum necessary part is processed. For example, the first embodiment will be specifically described as an example. In each internal tooth pin 3, only both

end portions

31 and 32 thereof are crowned and the intermediate portion 33 is not crowned. Further, in the first external teeth 14a and the second external teeth 14b, only the end portions adjacent to each other in the axial direction (the inner end portion of the first outer teeth 14a and the inner end portion of the second external teeth 16a) are crowned. Yes. Thereby, the increase in processing cost can be suppressed, suppressing that the edge stress arises between the 1st external tooth 14a and the 2nd external tooth 16a, and each internal tooth pin 3. FIG.

Moreover, in 1st and 2nd embodiment, compared with the gear transmission described in FIG. 7 of patent document 1, in addition to the advantage that a processing location is reduced by half, there is an advantage that processing dimension management is simplified. is there. Specifically, it is as follows.

In order to obtain the effect of the crowning process, the amount of correction (the amount of swelling or the amount of relief in the direction of the tooth trace) needs to be within the tolerance. In the gear transmission described in FIG. 7 of Patent Document 1, the crowning position of the inner tooth pin and the crowning position of the outer tooth are opposed to each other in the radial direction. Thus, when it has the processing part which mutually opposes to radial direction, the processing tolerance of 1/2 of the tolerance of the said modification amount is calculated | required at each processing part. That is, in the case of having machining portions that are opposed to each other in the radial direction, each machining portion is required to have a machining tolerance that is 1/2 of the machining tolerance that is required for the crowning machining portion in the present embodiment. If machining with a machining tolerance of 1/2 of the correction amount tolerance is impossible, it is necessary to widen the tolerance range of the crowning amount, which may reduce the effect of crowning.

On the other hand, in the first and second embodiments, the crowning position of the inner tooth pin and the crowning position of the outer tooth are not opposed in the radial direction. Therefore, the processing tolerances of the first reduced diameter portion 31 (34) and the second reduced diameter portion 32 (35) in the internal tooth pin may be the above-described adjustment amount tolerance. Further, since the processing tolerance is wide, it is not necessary to widen the tolerance range of the crowning amount. Thus, in 1st and 2nd embodiment, there exists an advantage that process management of a process becomes easy compared with the gear transmission described in FIG.

In 1st Embodiment, the 1st process part 142 is provided in the edge part by the side of the 2nd external tooth 16a among the axial direction both ends in the 1st external tooth 14a, and the 2nd process part 162 is a 2nd external tooth. The first reduced-diameter portion 31 is provided at one end portion in the axial direction of each internal tooth pin 3 and is provided at the end portion on the first outer tooth 14a side of both axial ends of 16a. 32 is provided at the other axial end of each internal tooth pin 3.

In this configuration, the diameter-reduced

portions

31 and 32 are provided at both axial ends of each internal tooth pin 3, and compared with the case where the diameter-reduced

portions

34 and 35 are provided at the axially intermediate portion as in the second embodiment. Processing becomes easier. Thereby, processing cost can be reduced more effectively.

As mentioned above, although embodiment of this invention was described, this invention is not limited to these embodiment, A various change, improvement, etc. are possible in the range which does not deviate from the meaning.

For example, in the above embodiment, the case where the outer peripheral surfaces (tooth surfaces) of the first reduced diameter portion and the second reduced diameter portion are curved outwardly convex is illustrated, but the present invention is not limited thereto. The outer peripheral surfaces of the first reduced diameter portion and the second reduced diameter portion may have a truncated cone shape, for example.

Moreover, in the said embodiment, the case where it was the site | part processed into the curved shape so that the tooth surface of the 1st process part 142 and the 2nd process part 162 may be located inside radial direction as it goes to an axial direction edge part was illustrated. However, it is not limited to this. The tooth surfaces of the first processing unit 142 and the second processing unit 162 are, for example, inclined surfaces that are inclined at, for example, an acute angle with respect to the axial direction in the cross section shown in FIG. 3 (a cross section parallel to the axial direction). Also good.

In the above embodiment, the case where the input shaft 8 is provided at the center in the radial direction is illustrated, but the present invention is not limited to this. The input shaft 8 may be provided at a position shifted in the radial direction from the center.

In the above-described embodiment, a case where a plurality of (for example, three) crankshafts are provided is illustrated. However, for example, one crankshaft may be provided at a radial center. In this case, it is also possible to adopt a configuration in which a cylinder is fitted into the through hole 4d, the through hole 4f, the through hole 14b, and the through hole 16b. For example, a cable or the like is disposed in the cylinder.

In the above embodiment, the carrier rotates relative to the outer cylinder. In other words, the carrier may be fixed and the outer cylinder may be rotated relative to the carrier, or the outer cylinder may be fixed and the carrier may be rotated relative to the outer cylinder. .

The specific embodiment described above will be outlined.

The gear transmission is
An outer cylinder having an inner peripheral surface in which a plurality of pin grooves extending in the axial direction are provided at predetermined intervals in the circumferential direction;
A plurality of internal teeth pins arranged in each of the plurality of pin grooves;
A crankshaft having a first eccentric portion and a second eccentric portion arranged side by side in the axial direction with a predetermined phase difference from each other, and provided to be rotatable around the axis in the outer cylinder;
It has an outer peripheral surface provided with first external teeth, is attached to the first eccentric portion, and swings in conjunction with the eccentric rotation of the first eccentric portion while the first external teeth mesh with the internal tooth pin. A rotating first external gear;
It has an outer peripheral surface provided with second external teeth, is attached to the second eccentric portion, and swings in conjunction with the eccentric rotation of the second eccentric portion while the second external teeth mesh with the internal tooth pin. A rotating second external gear,
A carrier that rotates relative to the outer cylinder by transmitting the swinging rotation of the first external gear and the second external gear.

In this configuration, the first processed portion is provided at any one end of the first external teeth, and the second processed portion is provided at any one end of the second external teeth. Each internal tooth pin has a first reduced diameter portion and a second reduced diameter portion at a portion that is radially opposed to an end portion where the first processed portion is not provided and an end portion where the second processed portion is not provided. Each of the reduced diameter portions is provided. That is, in order to suppress the occurrence of edge stress between the first external tooth and the second external tooth and each internal tooth pin, the minimum necessary amount in each of the first external tooth, the second external tooth, and each internal tooth pin. Processing is applied to the limited part. Thereby, increase in processing cost can be suppressed, suppressing that an edge stress arises between the 1st external tooth and the 2nd external tooth, and each internal tooth pin.

In the gear transmission, the first processed portion is provided at an end of the first external tooth on the second external tooth side, and the second processed portion is the first external tooth of the second external tooth. The first reduced diameter portion is provided at one end portion in the axial direction of each internal tooth pin, and the second reduced diameter portion is the other end portion in the axial direction of each internal tooth pin. It is preferable to be provided in the part.

In this configuration, a reduced diameter portion is provided at each axial end of each internal tooth pin. In this configuration, the machining becomes easier as compared with the case where the reduced diameter portion is provided in the axially intermediate portion of the internal tooth pin, so that the machining cost can be reduced more effectively.

DESCRIPTION OF SYMBOLS 1 Gear transmission 2 Outer cylinder 2b Pin groove 3

Inner tooth pin

31,34 1st

diameter reduction part

32,35 2nd diameter reduction part 33 Columnar part 36 1st columnar part 37 2nd columnar part 4 Carrier 10 Crankshaft 10a 1st 1 eccentric part 10b 2nd eccentric part 14 1st external gear 14a 1st external tooth 141 1st external tooth main-body part 142 1st process part 16 2nd external gear 16a 2nd external tooth 161 2nd external tooth main part 162 Second processing unit 20 Transmission gear

Claims

An outer cylinder having an inner peripheral surface in which a plurality of pin grooves extending in the axial direction are provided at predetermined intervals in the circumferential direction;
An internal tooth pin disposed in each of the plurality of pin grooves;
A crankshaft having a first eccentric portion and a second eccentric portion arranged side by side in the axial direction with a predetermined phase difference from each other, and provided to be rotatable around the axis in the outer cylinder;
It has an outer peripheral surface provided with first external teeth, is attached to the first eccentric portion, and swings in conjunction with the eccentric rotation of the first eccentric portion while the first external teeth mesh with the internal tooth pin. A rotating first external gear;
It has an outer peripheral surface provided with second external teeth, is attached to the second eccentric portion, and swings in conjunction with the eccentric rotation of the second eccentric portion while the second external teeth mesh with the internal tooth pin. A rotating second external gear,
A carrier that rotates relative to the outer cylinder by transmitting the swing rotation of the first external gear and the second external gear;
The first external tooth has a first processed portion at one end in the axial direction,
The tooth surface of the first processed portion is processed so as to be positioned radially inward as it goes toward the axial end of the tooth surface,
The second external tooth has a second processed portion at one end in the axial direction,
The tooth surface of the second processed portion is processed so as to be located radially inward as it goes toward the axial end of the tooth surface,
Each internal tooth pin has a first reduced diameter portion and a second reduced diameter portion,
The first reduced diameter portion is processed so that the diameter of the portion opposed to the end portion of the first external tooth on the side where the first processed portion is not provided decreases in the axial direction. And
The second reduced diameter portion is processed so that the diameter of the portion opposed to the end portion of the second external tooth on the side where the second processed portion is not provided decreases in the axial direction. The gear transmission.
The first processed portion is provided at an end of the first external tooth on the second external tooth side,
The second processed portion is provided at an end of the second external tooth on the first external tooth side,
The first reduced diameter portion is provided at one end in the axial direction of each internal tooth pin,
The gear transmission according to claim 1, wherein the second reduced diameter portion is provided at the other end portion in the axial direction of each internal tooth pin.