JP2015206378A - Gear transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a gear transmission device which is high in durability.SOLUTION: A gear transmission device comprises an inner tooth member 6 having an inner tooth gear at an internal periphery, and an outer tooth gear which relatively and eccentrically rotates with respect to the inner tooth gear while being engaged with the inner tooth gear. A plurality of grooves 9 are formed at an internal peripheral face 7 of the inner tooth member 6. A plurality of the grooves 9 extend along an axial line of the gear transmission device. A plurality of the grooves 9 are formed in a circumferential direction of the inner tooth member 6 at equal intervals. The inner tooth gear is formed by inserting columnar members 8 into the grooves 9. End parts of the columnar members 8 in an axial direction are short in lengths in the circumferential direction which contact with the grooves 9 compared with intermediate parts.

Description

  This specification discloses the technique regarding a gear transmission.

  A gear transmission having a structure in which an external gear meshes with an internal gear and rotates eccentrically relative to the internal gear is known. In such a gear transmission, a groove may be formed on the inner peripheral surface of the internal gear member, and a cylindrical member may be inserted into the groove to form an internal gear. Patent Document 1 discloses a gear transmission in which a plurality of grooves are formed on the inner peripheral surface of a case (internal tooth member), and an internal gear is formed by inserting a pin (columnar member) into each groove. Is disclosed.

JP 2006-46596 A

  The columnar member inserted into the groove corresponds to the internal teeth of the internal gear. The cylindrical member rotates inside the groove while meshing with the external gear. This groove is formed in the inner peripheral surface of the case. In the case of the internal gear having such a structure, the lubricant present between the groove and the cylindrical member may be discharged to the outside of the groove as the cylindrical member rotates. Therefore, the oil film may be cut off inside the groove, and the friction between the surface of the groove and the cylindrical member may increase. Alternatively, an oil film break may occur on the surface of the cylindrical member, and friction between the cylindrical member and the external gear may increase. As a result, the durability of the gear transmission can be reduced. This specification solves the said subject and discloses the technique which implement | achieves a highly durable gear transmission.

  The technology disclosed in this specification includes an internal gear member having an internal gear formed on the inner periphery, and an external gear that rotates eccentrically relative to the internal gear while meshing with the internal gear. The present invention relates to a gear transmission. In the gear transmission, a plurality of grooves are provided on the inner peripheral surface of the internal gear member. The plurality of grooves extend along the axis of the gear transmission on the inner peripheral surface of the internal gear member. The plurality of grooves are provided at equal intervals in the circumferential direction on the inner peripheral surface of the internal tooth member. The internal gear is formed by inserting a cylindrical member into the groove. In the gear transmission disclosed in the present specification, the end in the axial direction of the columnar member is shorter in the circumferential direction in contact with the groove than the intermediate portion in the axial direction of the columnar member.

  The columnar member inserted into the groove corresponds to the internal teeth of the internal gear. Hereinafter, in this specification, the groove formed on the inner peripheral surface of the internal tooth member may be referred to as an “insertion groove”. According to the gear transmission, the axial end of the columnar member has a smaller area in contact with the insertion groove than the intermediate portion. In other words, the end portion of the cylindrical member in the axial direction has a larger area exposed from the insertion groove than the intermediate portion. Therefore, the end portion of the columnar member has a large area in contact with the lubricant present outside the insertion groove. The lubricant that has come into contact with the end of the columnar member moves along the outer peripheral surface of the columnar member and moves to the intermediate portion of the columnar member. Lubricant is easily supplied between the insertion groove and the columnar member, and the oil film breakage in the insertion groove and the columnar member can be suppressed.

  The “external gear that rotates eccentrically relative to the internal gear” is not limited to the form in which the external gear rotates eccentrically with respect to the axis of the gear transmission, but the internal gear A form that rotates eccentrically with respect to the axis is also included. That is, “an external gear that rotates eccentrically relative to the internal gear” means that one of the internal gear and the external gear rotates eccentrically with respect to the axis of the gear transmission, and the internal gear and the external gear. It means that the gear rotates relatively eccentrically. In addition, the “end in the axial direction of the columnar member” includes both a form that is one end in the axial direction and a form that is both ends in the axial direction. The phrase “the length in the circumferential direction in contact with the groove is short” includes a form in which the end portion in the axial direction of the cylindrical member is not in contact with the insertion groove at all. That is, “the length in the circumferential direction in contact with the groove is short” includes a form in which a gap is provided between the inner peripheral surface of the internal tooth member and the columnar member.

Sectional drawing of the gear transmission of 1st Example is shown. FIG. 2 shows a cross-sectional view along the line II-II in FIG. 1. The partial expanded sectional view (partial enlarged view of FIG. 1) of an internal tooth member is shown. The figure for demonstrating the characteristic of 1st Example is shown. The figure for demonstrating the characteristic of 2nd Example is shown. The figure for demonstrating the characteristic of 3rd Example is shown. The figure for demonstrating the characteristic of 4th Example is shown.

  Hereinafter, some technical features of the gear transmission disclosed in this specification will be described. The items described below have technical usefulness independently.

  The gear transmission may include an internal gear and an external gear. The internal gear and the external gear may rotate relatively eccentrically while meshing with each other. That is, the external gear may rotate eccentrically while meshing with the internal gear. Alternatively, the internal gear may rotate eccentrically while meshing with the external gear. The internal gear may be formed on the inner peripheral surface of the ring-shaped internal gear member. The internal gear may be formed by a plurality of grooves (insertion grooves) formed on the inner peripheral surface of the internal tooth member and a cylindrical member inserted into the insertion groove. When the external gear rotates eccentrically, a carrier that supports the external gear may be provided. The carrier may be supported by the internal gear member via a pair of bearings (main bearings).

  When the external gear is of a type that rotates eccentrically, the internal gear member may also serve as the case of the gear transmission. That is, the internal gear may be formed on the inner periphery of the case. In this case, a carrier, a crankshaft, and an external gear may be arranged inside the case. The crankshaft may be rotatably supported by the carrier. The crankshaft may include an eccentric body. The external gear may engage with the eccentric body of the crankshaft and rotate eccentrically as the crankshaft rotates. The internal gear meshes with the external gear, and may have a number of teeth different from the number of teeth of the external gear.

  The cylindrical member inserted into the insertion groove may function as the teeth of the internal gear. In this case, the inner peripheral surface between adjacent insertion grooves among the inner peripheral surfaces of the internal gear member may function as a tooth groove of the internal gear. In the cross section orthogonal to the axis of the gear transmission, the shape of each insertion groove may be an arc. The plurality of insertion grooves may extend along the axis of the gear transmission. In this case, each insertion groove may be provided at equal intervals in the circumferential direction of the internal tooth member. In the case of an arc-shaped insertion groove, the center of the virtual circle including the surface of the insertion groove and the rotation axis of the cylindrical member are coaxial, and the diameter of the virtual circle and the diameter of the cylindrical member may be substantially equal. The columnar member may rotate in the insertion groove and function as a sliding bearing between the external gear and the insertion groove.

  The end in the axial direction of the columnar member may be shorter in the circumferential direction in contact with the insertion groove than the intermediate portion in the axial direction. That is, the end portion of the cylindrical member in the axial direction may have a larger area exposed from the insertion groove than the intermediate portion. One end portion in the axial direction may have a larger area exposed from the insertion groove than the intermediate portion. Or the area which the both ends of an axial direction expose from the insertion groove may be large compared with an intermediate part. Moreover, the edge part of the axial direction of a cylindrical member may be separated from the internal peripheral surface (insertion groove) of an internal gear member over the perimeter of the circumferential direction. The movement of the columnar member in the axial direction may be restricted by the race of the main bearing described above.

  An inclined portion that makes a round in the circumferential direction of the internal tooth member may be provided on the internal peripheral surface of the internal tooth member at a position facing the end in the axial direction of the columnar member. By providing the inclined portion, the thickness of the side wall defining the insertion groove may be thinner at the end portion in the radial direction of the gear transmission as compared with the intermediate portion of the insertion groove. When the gear transmission is viewed in plan (observed from the axial direction of the gear transmission), the end (outer edge) on the large-diameter side of the inclined portion is located outside the insertion groove in the radial direction of the gear transmission. You can do it. In this case, the end of the insertion groove may be located in the inclined portion in the axial direction of the gear transmission. In other words, the cylindrical member may be located in the inclined portion when observed from the axial direction of the gear transmission.

  The large-diameter side of the inclined portion may be located on the outer side in the axial direction of the gear transmission than the small-diameter side of the inclined portion. That is, in the portion where the inclined portion is provided, the thickness of the internal gear member in the radial direction of the gear transmission may increase from the end portion of the internal gear member in the axial direction of the gear transmission toward the central portion. . The inclined portion may be provided locally at the end of the insertion groove in the axial direction of the gear transmission. In this case, the inclined portion does not go round in the circumferential direction of the internal tooth member, and may be provided at equal intervals in the circumferential direction.

  The depth of the insertion groove may be deeper than the position facing the axial middle portion of the columnar member at the position facing the axial end of the columnar member. In other words, in the axial direction of the gear transmission, an insertion groove (first insertion groove) that contacts the columnar member and an insertion groove (second insertion groove) that does not contact the columnar member are continuously provided. The second insertion groove may be provided at a position facing the axial end of the columnar member. The center of the first virtual circle including the surface of the first insertion groove and the center of the second virtual circle including the surface of the second insertion groove may be located on the same axis. The diameter of the second virtual circle may be larger than the diameter of the first virtual circle.

(First embodiment)
With reference to FIG.1 and FIG.2, the basic structure of the gear transmission 100 is demonstrated. FIG. 1 shows a longitudinal sectional view of the gear transmission 100 (a sectional view along the axis 12 of the gear transmission 100). FIG. 2 shows a cross-sectional view of the gear transmission 100 (cross-sectional view along a line perpendicular to the axis 12 of the gear transmission 100). The gear transmission 100 includes an internal gear 10, a carrier 4, a crankshaft 14, and an external gear 28. The internal gear 10 is formed by arranging a plurality of internal gear pins 8 on the inner periphery of the case 6. The internal tooth pin 8 has a cylindrical shape and is inserted into an insertion groove 9 formed on the inner peripheral surface 7 of the case 6. The case 6 is an example of an internal tooth member, and the internal tooth pin 8 is an example of a columnar member.

  The carrier 4 is rotatably supported by the case 6 by a pair of bearings 22 (hereinafter sometimes referred to as main bearings 22). The main bearing 22 restricts the carrier 4 from moving in the axial direction and the radial direction with respect to the case 6. In the gear transmission 100, an angular ball bearing is used as the main bearing 22. The outer race 24 of the main bearing 22 covers the axial end surface of the internal tooth pin 8. In other words, the internal tooth pin 8 is disposed between the outer races 24 of the main bearing 22. The inner tooth pin 8 is restricted from moving in the axial direction by the outer race 24.

  The carrier 4 includes a first plate 4a and a second plate 4c. The first plate 4a includes a columnar portion 4b. The columnar portion 4b extends from the first plate 4a toward the second plate 4c, and is fixed to the second plate 4c by bolts. The bolt 34 passes through the second plate 4c and is fastened to a bolt groove 34a provided in the columnar portion 4b. An oil seal 18 is disposed between the case 6 and the first plate 4a. A positioning pin (not shown) for positioning in the circumferential direction is inserted into the columnar part 4b and the second plate 4c. FIG. 2 shows a pin hole 36 provided in the columnar portion 4b. The second plate 4c is also provided with pin holes (not shown). The positioning pin passes through the pin hole of the second plate 4 c and is inserted into the pin hole 36.

  The crankshaft 14 is rotatably supported by the carrier 4 by a pair of bearings 20. The pair of bearings 20 restricts the crankshaft 14 from moving in the axial direction and the radial direction with respect to the carrier 4. In the gear transmission 100, tapered roller bearings are used as the pair of bearings 20. The crankshaft 14 includes an input gear 32 and two eccentric bodies 30. The eccentric body 30 is disposed between the pair of bearings 22. The eccentric body 30 is engaged with the external gear 28 via the cylindrical roller bearing 26. The external gear 28 is supported by the carrier 4 via the crankshaft 14. The input gear 32 is disposed outside the pair of bearings 20.

  In the gear transmission 100, torque of a motor (not shown) is transmitted to the input gear 32. When the torque of the motor is transmitted to the input gear 32, the eccentric body 30 rotates eccentrically as the crankshaft 14 rotates. As the eccentric body 30 rotates eccentrically, the external gear 28 rotates eccentrically while meshing with the internal gear 10. The external gear 28 rotates eccentrically around the axis 12. The two eccentric bodies 30 are eccentrically symmetrical to each other. Therefore, the two external gears 28 eccentrically rotate symmetrically around the axis 12. The number of teeth of the external gear 28 and the number of teeth of the internal gear 10 (number of internal pins 8) are different (see FIG. 2). Therefore, when the external gear 28 rotates eccentrically, the carrier 4 supporting the external gear 28 rotates relative to the case 6 according to the difference in the number of teeth between the external gear 28 and the internal gear 10. The axis 12 can also be referred to as the rotation axis of the carrier 4.

  The characteristics of the case 6 will be described with reference to FIGS. FIG. 4 schematically shows the characteristics of the case 6 and does not accurately show the actual size. In FIG. 3, the internal tooth pin 8 and the external gear 28 are indicated by a one-dot chain line, and in FIG. 4, the internal tooth pin 8 is indicated by a broken line. The inner peripheral surface 7 of the intermediate portion 6a of the case 6 protrudes toward the axis 12 as compared with the end portion 6b. In other words, the inner diameter of the intermediate portion 6a is smaller than the inner diameter of the end portion 6b. Flat portions 11 are provided at both ends of the intermediate portion 6a (both ends in the direction of the axis 12). The outer race 24 of the main bearing 22 is positioned by the flat portion 11 (see also FIG. 1). The flat part 11 restricts the movement of the main bearing 22 in the direction of the axis 12. Thereby, the preload of the carrier 4 with respect to the case 6 can be adjusted. The flat part 11 can also be called a race support part. The intermediate portion 6a is provided with an insertion groove 9 and an inclined portion 9a. As shown in FIG. 2, the inclined portion 9 a makes a round in the circumferential direction of the case 6. In the radial direction of the gear transmission 100 (direction perpendicular to the axis 12), the outer periphery of the inclined portion 9 a is located outside the insertion groove 9. That is, the end portion (outer edge) on the large diameter side of the inclined portion 9 a is located outside the bottom of the insertion groove 9.

  As described above, the movement of the inner tooth pin 8 in the direction of the axis 12 is restricted by the outer race 24. As shown in FIG. 3, the internal tooth pin 8 extends to substantially the same position as the flat portion 11. In other words, the end of the internal tooth pin 8 extends to a position where the inclined portion 9a is provided. Further, the external gear 28 is configured to contact the entire direction of the axis 12 of the internal tooth pin 8. Therefore, a part of the tooth surface of the external gear 28 (a part of the tooth surface in the direction of the axis 12) faces the inclined portion 9a in the radial direction (a direction orthogonal to the axis 12). As shown in FIG. 4, the end of the insertion groove 9 is located in the inclined portion 9a. That is, the insertion groove 9 does not extend to the flat portion 11. Therefore, the end portion of the internal tooth pin 8 protrudes from the insertion groove 9. In other words, the end of the internal tooth pin 8 is not in contact with the inner peripheral surface 7 of the case 6. The end portion of the internal tooth pin 8 is separated from the inner peripheral surface 7 of the case 6 over the entire circumference in the circumferential direction. Since the end portion of the internal tooth pin 8 is exposed from the insertion groove 9, it is easy to come into contact with the lubricant. Moreover, the depth of the insertion groove 9 in the inclined portion 9a is deeper than the other portions. Therefore, a gap is provided between the insertion groove 9 and the internal tooth pin 8 in the inclined portion 9a. Lubricant is easily held in this gap. As is clear from FIGS. 3 and 4, the radial thickness of the side wall (case 6) defining the insertion groove 9 is thinner at the end than the intermediate part of the insertion groove 9.

  A manufacturing process of the case 6 will be briefly described. Here, the process of the inner part of the case 6 will be described. First, both sides of the inner peripheral surface of the case 6 are scraped, and the inner diameters of both end portions 6b of the case 6 are made larger than those of the intermediate portion 6a. Thereby, the flat part 11 is formed in the axial direction edge part of the intermediate part 6a. Next, the corner portion of the intermediate portion 6a (the end portion on the axis 12 side of the flat portion 11) is cut so as to make a round in the circumferential direction of the case 6 (see also FIG. 1). In the case 6, the corners on both sides of the intermediate portion 6a are cut off. Thereby, the inclined part 9a is formed in the intermediate part 6a. Thereafter, along the axis 12, the intermediate portion 6 a is scraped to form the insertion groove 9. At this time, the tool for forming the insertion groove 9 first comes into contact with the inclined portion 9a. That is, the tool for forming the insertion groove 9 cuts the inner side (axis 12 side) from the large-diameter end of the inclined portion 9a.

  The advantages of the gear transmission 100 will be described. As described above, the internal tooth pin 8 constitutes the internal gear 10 and is inserted into the insertion groove 9. At the intermediate portion of the internal tooth pin 8, the surface of the internal tooth pin 8 is in contact with the insertion groove 9, and it is difficult to contact the lubricant outside the insertion groove 9. However, in the gear transmission 100, the end portion of the internal tooth pin 8 is not in contact with the inner peripheral surface 7 (insertion groove 9) of the case 6, so that it can be in contact with the lubricant outside the insertion groove 9. Further, the lubricant can be held in the gap between the insertion groove 9 and the internal tooth pin 8 at the position where the inclined portion 9a is formed. Therefore, the lubricant can move from the end portion of the internal tooth pin 8 to the intermediate portion along the outer periphery of the internal tooth pin 8. As a result, the oil film breakage between the internal tooth pin 8 and the insertion groove 9 can be suppressed. Moreover, the oil film breakage between the internal tooth pin 8 and the external gear 28 can be suppressed. That is, by providing the inclined portion 9a, the friction between the internal tooth pin 8 and the insertion groove 9 and / or between the internal tooth pin 8 and the external gear 28 can be reduced.

  The internal tooth pin 8 needs to be inserted into the insertion groove 9 along the direction in which the insertion groove 9 extends (the direction of the axis 12). For example, when the inclined portion 9 a is not provided, it is necessary to insert the internal tooth pin 8 into the insertion groove 9 while keeping the internal tooth pin 8 parallel to the axis 12. As described above, the internal tooth pin 8 functions as a sliding bearing with respect to the insertion groove 9. Therefore, the size of the insertion groove 9 (diameter of the virtual circle) and the size of the internal tooth pin 8 (outer diameter) are substantially equal. That is, there is almost no gap between the internal tooth pin 8 and the insertion groove 9. The operation of inserting the internal tooth pin 8 into the insertion groove 9 having almost no gap while keeping the internal tooth pin 8 parallel to the axis 12 is complicated. By providing the inclined portion 9a as in the gear transmission 100, when the internal tooth pin 8 is inserted into the insertion groove 9, it can be inserted along the inclined portion 9a. That is, when inserting the internal tooth pin 8 into the insertion groove 9, it is not necessary to keep the internal tooth pin 8 parallel to the axis 12. The manufacturing process (the process of inserting the internal tooth pin 8 into the insertion groove 9) of the gear transmission 100 can be simplified.

  As described above, when the insertion groove 9 is formed on the inner peripheral surface 7 of the case 6, the tool for forming the insertion groove 9 first comes into contact with the inclined portion 9a. When the tool first comes into contact with the inclined portion 9a, it is possible to suppress the occurrence of burrs at the end of the insertion groove 9 as compared with the case where the insertion groove is formed in the case where the inclined portion 9a is not provided. . By providing the inclined portion 9a, it is possible to simplify the process of removing the burr after the insertion groove 9 is formed. That is, the manufacturing process (deburring process) of the gear transmission 100 can be simplified.

  Moreover, since a tool contacts the inclined part 9a when forming the insertion groove 9, the load added to the tool which forms the insertion groove 9 can be reduced. Therefore, since the rotation speed and / or movement speed of the tool can be increased, the processing time of the insertion groove 9 can be shortened. In addition, the gear transmission 100 increases the process of forming the inclined part 9a compared with the conventional gear transmission which is not provided with the inclined part. However, since the inclined portion 9a goes around the inner peripheral surface 7 of the case 6, the inclined portion 9a can be formed in one process per one side. Compared with the step of removing burrs generated in each insertion groove 9, the manufacturing time can be greatly shortened.

(Second embodiment)
FIG. 5 shows a part of the gear transmission of the second embodiment. Specifically, the shape of the case 206 is different from the case 6 of the gear transmission 100. The other structure is substantially the same as that of the gear transmission 100. The same parts as those of the gear transmission 100 may be denoted by the same reference numerals or the same last two digits, and the description thereof may be omitted. FIG. 5 shows a portion corresponding to FIG. 4 describing the gear transmission 100.

  As shown in FIG. 5, the large-diameter side end portion of the inclined portion 209 a is located radially inward from the bottom of the insertion groove 209. In other words, the diameter of the large diameter side end portion of the inclined portion 209a is smaller than the inclined portion 9a. In the case 206, the area of the flat portion 211 is larger than that in the case 6. Therefore, the contact area between the outer race 24 of the bearing 22 (see also FIG. 1) and the case 206 is increased, and the bearing 22 can be supported more reliably. In the case of the case 206, when the insertion groove 209 is formed on the inner peripheral surface, the tool first contacts both the flat portion 211 and the inclined portion 209a.

  In the case of the case 206, the end portion of the internal tooth pin 8 has a smaller area in contact with the insertion groove 209 than the central portion. Therefore, the end portion of the internal tooth pin 8 is likely to come into contact with the lubricant present outside the insertion groove 209. The lubricant adhering to the end portion of the internal tooth pin 8 moves to the intermediate portion of the internal tooth pin 8 and between the internal tooth pin 8 and the insertion groove 9 and / or between the internal tooth pin 8 and the external gear 28. Oil film breakage can be suppressed (see also FIG. 2).

(Third embodiment)
FIG. 6 shows a part of the gear transmission of the third embodiment. Specifically, the shape of the case 306 is different from that of the case 6 of the gear transmission 100. The other structure is substantially the same as that of the gear transmission 100. The same parts as the gear transmission 100 may be denoted by the same reference numerals or the same last two digits, and the description thereof may be omitted. FIG. 6 shows a portion corresponding to FIG. 4 describing the gear transmission 100.

  As shown in FIG. 6, the case 306 does not include an inclined portion. The case 306 is provided with two insertion grooves (a first insertion groove 309 and a second insertion groove 309a) having different diameters. The center of the first virtual circle including the surface of the first insertion groove 309 and the center of the second virtual circle including the surface of the second insertion groove 309a are located on the same axis. Further, the diameter of the second virtual circle is larger than the diameter of the first virtual circle. That is, the second insertion groove 309a is deeper than the first insertion groove 309. The first insertion groove 309 faces the axial intermediate portion of the internal tooth pin 8, and the second insertion groove 309 a faces the axial end portion of the internal tooth pin 8. The first insertion groove 309 and the second insertion groove 309a communicate with each other. The internal tooth pin 8 contacts the surface of the first insertion groove 309 and does not contact the surface of the second insertion groove 309a. Therefore, a gap is provided between the inner tooth pin 8 and the case 306 on the end side of the inner tooth pin 8. A lubricant is held between the second insertion groove 309a and the internal tooth pin 8, and the lubricant can move to an intermediate portion of the internal tooth pin 8 (a portion inserted into the first insertion groove 309).

  The case 306 has a larger area of the flat portion 311 than the case 6. Therefore, the contact area between the outer race 24 of the bearing 22 and the case 306 can be increased. In the case of the case 306, the internal tooth pin 8 is inserted into the first insertion groove 309 through the second insertion groove 309a. Since the diameter of the second insertion groove 309 a is larger than the diameter of the internal tooth pin 8, the work can be facilitated as compared with the form in which the internal tooth pin 8 is directly inserted into the first insertion groove 309.

(Fourth embodiment)
FIG. 7 shows a part of the gear transmission of the fourth embodiment. Specifically, the shape of the case 406 is different from that of the case 6 of the gear transmission 100. The other structure is substantially the same as that of the gear transmission 100. The same parts as the gear transmission 100 may be denoted by the same reference numerals or the same last two digits, and the description thereof may be omitted. FIG. 7 shows a portion corresponding to FIG. 4 describing the gear transmission 100.

  Like the case 306, the case 406 does not include an inclined portion. In the case of the case 406, the diameter of the second insertion groove 409a decreases as it approaches the first insertion groove 409. In other words, the case 406 includes a plurality of inclined portions (second insertion grooves) 409 a in the circumferential direction of the case 406. Therefore, it is easy to insert the internal tooth pin 8 into the first insertion groove 409, and the lubricant can be stored at the end of the internal tooth pin 8. Further, a large area of the support portion 411 can be secured. Furthermore, since the tool for forming the first insertion groove 409 is first in contact with the inclined portion (second insertion groove) 409a, the deburring process can be simplified.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

6: Internal tooth member 7: Inner peripheral surface 8: Columnar member 9: Groove 10: Internal gear 28: External gear 100: Gear transmission

Claims (4)

A gear transmission comprising: an internal gear member having an internal gear formed on the inner periphery; and an external gear rotating eccentrically relative to the internal gear while meshing with the internal gear;
A plurality of grooves extend along the axis of the gear transmission on the inner peripheral surface of the internal gear member, and are provided at equal intervals in the circumferential direction.
The internal gear is formed by inserting a cylindrical member into the groove,
An end portion in the axial direction of the columnar member is a gear transmission having a short circumferential length in contact with the groove as compared with an intermediate portion in the axial direction of the columnar member.   The gear transmission according to claim 1, wherein an inclined portion that makes a round in the circumferential direction of the internal gear member is provided on the internal peripheral surface of the internal gear member at a position facing the axial end of the columnar member.   The gear transmission according to claim 2, wherein when viewed from the axial direction of the gear transmission, the end portion on the large-diameter side of the inclined portion is located outside the groove.   The gear transmission according to any one of claims 1 to 3, wherein a depth of the groove is deeper than a position facing an axial intermediate portion of the columnar member at a position facing the axial end portion of the columnar member. apparatus.

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