JP6535447B2 - Gear transmission - Google Patents

Description

  The present specification discloses a technology related to a gear transmission.

  A gear transmission comprising: an internal gear member provided with an internal gear on an inner periphery thereof; and an external gear having a number of teeth different from the number of teeth of the internal gear and rotating eccentrically while meshing with the internal gear. Are known. In such a gear transmission, a carrier is used to support an external gear, and an internal gear rotatably supports the carrier. When the external gear is eccentrically rotated while meshing with the internal gear, the external gear and the internal gear rotate relative to each other according to the difference in the number of teeth of the external gear and the internal gear. As a result, the carrier supporting the external gear rotates with respect to the internal gear. Patent Document 1 discloses a gear transmission in which supporting members for supporting the carrier are disposed on both sides of the internal gear member in the rotation axis direction of the carrier. More specifically, support members that double as outer rings of the bearings are fixed to both sides of the internal gear members. In the support member and the internal gear member, bolt holes for passing bolts for fixing the both are formed from the end surface of one support member to the end surface of the other support member through the internal gear member.

JP-A-3-41240

  In the gear transmission of patent document 1, the protrusion part extended toward an internal tooth member is provided in the inner peripheral surface side (radial direction inner side) of a supporting member. Positioning the support member and the internal gear member in the radial direction is performed by bringing the protrusion into contact with the inner circumferential surface of the internal gear member. In the case of the gear transmission of Patent Document 1, when a force is applied from the carrier to the support member, the force is also applied to the internal gear member. Therefore, in the case of the gear transmission of patent document 1, in order to prevent that an internal-tooth member deform | transforms, it is required to thicken the thickness of the radial direction of an internal-tooth member. As a result, the radial size of the gear transmission is increased. This specification solves the above-mentioned subject and discloses art which realizes a compact gear transmission.

The gear transmission disclosed in the present specification includes an internal gear member, an external gear, a carrier, and a support member. An internal gear is provided on the inner periphery of the internal gear member. The external gear has a number of teeth different from the number of teeth of the internal gear, and rotates eccentrically while meshing with the internal gear. The carrier supports the external gear and is rotatable relative to the internal gear. The support members are disposed on both sides of the internal gear member in the rotational axis direction of the carrier. Also, the support member rotatably supports the carrier. In the above-described gear transmission, the internal gear member and the support member are provided with bolt holes through which bolts for fixing the both pass. The bolt holes extend along the rotation axis of the carrier, and a plurality of bolt holes are provided around the rotation axis. Further, positioning portions for positioning the internal tooth members and the support member in the radial direction are provided radially outside the circle connecting the end portions of the bolt holes located on the rotary shaft side of the carrier in the radial direction. . The material of the support member is stronger than the material of the internal tooth member.

  According to the above-described gear transmission, a circle (hereinafter referred to as a reference circle) in which the positioning portions of the support member and the internal tooth member connect the end portions of the bolt holes located on the rotary shaft side of the carrier. Located radially outward of the In other words, the radial positioning portions of the support member and the internal tooth member are not positioned radially inward of a circle (reference circle) connecting the end portions of the plurality of bolt holes located on the rotation shaft side. The support member and the internal gear member are restrained by the bolt passing through the bolt hole. The restraining force acting between the support member and the internal gear increases as it approaches the bolt hole (bolt). Therefore, as the radial positioning portions of the support member and the internal gear member are made closer to the bolt holes, the influence exerted by the carrier on the support member on the internal gear member is reduced. In other words, when the positioning portion is provided at a position close to the rotation axis of the carrier, the restraining force acting between the support member and the internal gear is small, so the force exerted by the carrier on the support member has a greater influence on the internal gear . The above-described gear transmission can suppress the influence exerted by the carrier on the support member from the carrier exerting on the internal gear, so that the radial thickness of the internal gear can be thinner than in the prior art. The size can be reduced.

  The restraining force acting between the support member and the internal tooth member becomes weaker as it goes radially outward from the bolt hole. Therefore, if the positioning portions of the support member and the internal gear member are positioned radially outward of the bolt hole, it may be considered that the force exerted by the carrier on the support member exerts a great influence on the internal gear member. However, the support member and the internal gear member are firmly fixed by bolts at the positions where the bolt holes are formed. Therefore, the force applied to the internal tooth member is dispersed outside the bolt hole in the radial direction. Even if the force applied to the internal gear is not dispersed radially outward of the bolt hole, the support member and the internal gear are firmly fixed at the position where the bolt hole is formed, so that The force applied to the internal gear member at the radially outer side can be prevented from deforming the radially inner portion of the internal gear member relative to the bolt hole. Therefore, the radial direction size of the gear transmission can be reduced by providing the positioning portions of the support member and the internal tooth member radially outside the reference circle.

  The “bolt for fixing the internal gear member and the support member” may be a bolt for fixing only the internal gear member and the support member to each other, or both of the internal gear member and the support member may be a counterpart member It may be a bolt for fixing the gear transmission to a member fixed to the gear transmission or a member driven by the gear transmission.

The cross section of the gear transmission of the 1st example is shown. The expanded sectional view of the part enclosed with broken line II of FIG. 1 is shown. The figure which looked at the gear transmission of 1st Example in the arrow A 1 direction of FIG. 1 is shown. Sectional drawing of the gear transmission of 2nd Example is shown. The expanded sectional view of the part enclosed with the broken line V of FIG. 4 is shown.

  The following describes some of the technical features of the gear transmission disclosed herein. The items described below each have technical usefulness alone.

  The gear transmission may comprise an external gear and an internal gear having a number of teeth different from the number of teeth of the external gear. The external gear may eccentrically rotate around the axis of the gear transmission while meshing with the internal gear. The external gear may have a crankshaft including an eccentric to eccentrically rotate the external gear. The external gear may be supported by a carrier that rotates relative to the internal gear. The crankshaft may be supported by the carrier, and the external gear may be supported by the carrier via the crankshaft.

  The internal gear may include an internal tooth member having a plurality of grooves provided on the inner periphery thereof and an internal tooth pin disposed in the groove. More specifically, the internal gear member constitutes a part of the case and is provided with a plurality of grooves along the axis of the gear transmission on the inner peripheral surface, and cylindrical pins are arranged in the plurality of grooves. By doing this, the internal gear may be configured. Support members may be arranged on both sides of the internal gear in the axial direction of the gear transmission. The support member may be part of the case. The internal gear members and the support member may be fixed by bolts. Both the internal tooth member and the support member may be provided with through holes from the end of one support member to the end of the other support member. The through hole may be a bolt hole for fixing the internal gear member and the support member. A plurality of bolt holes may be provided in the circumferential direction of the gear transmission.

  At least one of the internal gear member and the support member may be provided with a positioning portion for positioning the both in the radial direction. The positioning portion may be a protrusion extending from the radial end of the internal tooth member toward the support member, or a protrusion extending from the radial end of the support member toward the internal tooth member. The positioning portion may be provided radially outside (the side away from the rotation axis of the carrier) from a circle connecting the end portions of the bolt holes located on the inside in the radial direction (the rotation axis side of the carrier). Also, the positioning portion may be provided at the radial end of the internal tooth member or the support member. More specifically, the radial end of the internal tooth member is located outside the radial end of the support member, and extends toward the support member while supporting the radial end of the internal tooth member toward the support member A projection may be provided which contacts the radial end of the member. Alternatively, the radial end of the support member is located outside the radial end of the internal tooth member, extends toward the internal tooth member at the radial end of the support member, and the diameter of the internal tooth member A projection may be provided which contacts the directional end. When the radial end of the support member is provided with a protrusion, the material of the support member may be a material of higher strength than the material of the internal tooth member.

(First embodiment)
The basic structure of the gear transmission 100 will be described with reference to FIGS. 1 to 3. FIG. 1 shows a longitudinal sectional view of the gear transmission 100 (a sectional view along the axis 34 of the gear transmission 100). The gear transmission 100 includes an internal gear 24, a carrier 6, a crankshaft 14 and two external gears 18. The internal gear 24 includes an internal gear 22 and an internal pin 20. A plurality of grooves extending along the axis 34 are provided on the inner peripheral surface of the internal gear member 22. The grooves are equally spaced about the axis 34. The internal gear 24 is formed by arranging the internal tooth pins 20 in the grooves. The internal tooth pin 20 is cylindrical and corresponds to the teeth of the internal gear 24. The internal tooth member 22 is provided with a through hole 22a (see FIG. 2). The internal gear member 22 is a part of the case of the gear transmission 100.

  Support members 26 and 28 are disposed on both sides of the internal gear member 22 in the direction of the axis 34. A through hole 26 a is provided in the support member 26, and a through hole 28 a is provided in the support member 28. The support members 26, 28 are part of the case. The through holes 22a, 26a and 28a communicate with each other. The through holes 22a, 26a and 28a are bolt holes, through which bolts (not shown) for fixing the internal tooth member 22 and the support members 26 and 28 to the other members pass. The internal tooth member 22 and the support members 26, 28 are fixed by bolts passing through the through holes 22a, 26a and 28a. By fixing the internal tooth member 22 and the support members 26, 28, the case of the gear transmission 100 is completed.

  The outer diameter of the internal tooth member 22 is larger than the outer diameter of the support members 26, 28. Further, protrusions 22 b and 22 c extending in the direction of the axis 34 are provided at radial end portions of the internal gear member 22. The protrusion 22 b extends so as to surround a part of the support member 26 and is in contact with the outer peripheral surface of the support member 26. The protrusion 22 b contacts the outer peripheral surface of the support member 26 to position the internal tooth member 22 and the support member 26. The protrusion 22 c extends so as to surround a part of the support member 28 and is in contact with the outer peripheral surface of the support member 28. The protruding portion 22 c contacts the outer peripheral surface of the support member 28 to position the internal tooth member 22 and the support member 28. The protrusions 22 b and 22 c are an example of a positioning unit.

  The carrier 6 is rotatably supported by the support members (cases) 26 and 28 by a pair of bearings 4 (4a and 4b). The pair of bearings 4 restricts the movement of the carrier 6 in the axial direction and the radial direction with respect to the support members 26 and 28. In the gear transmission 100, angular ball bearings are used as the pair of bearings 4. Each of the support members 26 and 28 doubles as an outer race of the bearing 4. Specifically, a protrusion 26 b protruding toward the axis 34 is provided on the inner peripheral surface of the support member 26, and a protrusion 28 b protruding toward the axis 34 is provided on the inner peripheral surface of the support member 28. It is provided. By providing the protruding portions 26 b and 28 b, the support members 26 and 28 function as an outer race of the bearing 4.

  The protrusions 26 b and 28 b are provided at the end on the internal tooth member 22 side in the direction of the axis 34. Further, the projecting portions 26 b and 28 b make one round around the axis 34. An internal tooth pin 20 is disposed between the protrusions 26b and 28b. In other words, the protrusions 26 b and 28 b (the outer races of the pair of bearings 4) restrict the movement of the internal tooth pin 20 in the direction of the axis 34. The protrusions 26 b and 28 b are located radially outward of the end near the axis 34 of the internal tooth pin 20 (inward in the radial direction). More specifically, the radially inner end surfaces of the protrusions 26 b and 28 b are the first circle in contact with the end near the axis 34 of the internal tooth pin 20 and the side far from the axis 34 of the internal tooth pin 20 It is located between the 2nd circle which touches an end. Thereby, the protrusions 26 b and 28 b (support members 26 and 28) can be prevented from contacting the surface 18 a of the external gear 18. Such a configuration can prevent the support members 26 and 28 from obstructing the operation of the external gear 18.

  The carrier 6 includes a first plate 6a and a second plate 6c. The first plate 6a and the second plate 6c are disposed to face each other at an interval. The first plate 6a includes a columnar portion 6b. The columnar portion 6 b extends from the first plate 6 a to the second plate 6 c and is fixed to the second plate 6 c. A support member 26 is disposed to surround the outside of the first plate 6 a in the radial direction (direction orthogonal to the axis 34). Moreover, the protrusion part which protrudes toward the supporting member 26 is provided in the radial direction edge part of the 1st plate 6a. The first plate 6a doubles as an inner race of the bearing 4a. A support member 28 is disposed so as to surround the radially outer side of the second plate 6c. Moreover, the protrusion part which protrudes toward the supporting member 28 is provided in the radial direction edge part of the 2nd plate 6c. The second plate 6c doubles as an inner race of the bearing 4b.

  A ball (rolling element) 5a is disposed between the support member 26 and the first plate 6a. The bearing 4a is constituted by the support member 26, the first plate 6a and the ball 5a. A ball 5 b is disposed between the support member 28 and the second plate 6 c. The bearing 4b is comprised by the supporting member 28, the 2nd plate 6c, and the ball 5b. As described above, the support members 26 and 28 are fixed and constitute a part of the case. In addition, the first plate 6 a and the second plate 6 c are fixed to constitute the carrier 6. Therefore, it can be said that the carrier 8 is rotatably supported on the case by the pair of bearings 4 (4a, 4b). The oil seal 2a is disposed between the support member 26 and the first plate 6a. In addition, an oil seal 2b is disposed between the support member 28 and the second plate 6c. The oil seal 2 (2a, 2b) prevents the lubricant in the gear transmission 100 from leaking to the outside of the gear transmission 100.

  The crankshaft 14 is rotatably supported on the carrier 6 by a pair of tapered roller bearings 8. The crankshaft 14 comprises an input gear 32 and two eccentrics 12. The eccentric direction of each of the two eccentric bodies 12 is symmetrical with respect to the rotation axis 30 of the crankshaft 14. The two eccentric bodies 12 are disposed between the pair of tapered roller bearings 8. The input gear 32 is disposed outside the pair of tapered roller bearings 8. As shown in FIG. 3, the gear transmission 100 includes three crankshafts 14. Each crankshaft 14 is equally spaced about an axis 34.

  An external gear 18 is engaged with each eccentric 12 via cylindrical roller bearings 16. The external gear 18 eccentrically rotates around the axis 34 as the crankshaft 14 rotates. Each external gear 18 is eccentrically symmetrical with respect to the axis 34. At the radial direction end of the external gear 18, the total thickness (length in the direction of the axis 34) of the two external gears 18 is thicker than the axial length of the internal tooth pin 20.

  An output gear 36 of a motor (not shown) meshes with the input gear 32. When the torque of the motor is transmitted to the input gear 32, the crankshaft 14 rotates around the rotation axis 30. When the crankshaft 14 rotates, the eccentric body 12 eccentrically rotates around the rotation shaft 30. With the eccentric rotation of the eccentric body 12, the external gear 18 is eccentrically rotated while meshing with the internal gear 24. The external gear 18 eccentrically rotates around an axis 34. The number of teeth of the external gear 18 and the number of teeth of the internal gear 24 (the number of internal tooth pins 20) are different. Therefore, when the external gear 18 rotates eccentrically, the internal gear 24 rotates on the external gear 18 according to the difference in the number of teeth of the external gear 18 and the internal gear 24.

  The external gear 18 is supported by the carrier 6 via a crankshaft 14. Further, the internal gear 24 is formed on the inner periphery of the internal gear member (part of the case) 22. Therefore, when the external gear 18 eccentrically rotates, the carrier 6 rotates relative to the case. When the carrier 6 constitutes the output of the gear transmission 100, the carrier 6 rotates around the axis 34. When the support member (case) 26 constitutes the output of the gear transmission 100, the case rotates about the axis 34. That is, the axis 34 is also the rotational axis of the carrier 6 and the rotational axis of the case.

  The advantages of the gear transmission 100 will be described. As described above, the positioning portions 22b and 22c are provided radially outward of the bolt holes (the through holes 26a, 22a and 28a). Therefore, the force applied from the carrier 6 to the support members 26 and 28 does not easily act on the internal tooth member 22 inside the bolt hole. Inside the bolt hole of the internal gear member 22 is a portion constituting the internal gear 24. When the force applied from the carrier 6 to the support members 26 and 28 directly acts on the inner portion of the internal gear member 22, it is necessary to increase the thickness of the internal gear member 22 in order to prevent the deformation of the internal gear 24. is there. In the gear transmission 100, since the force applied from the carrier 6 to the support members 26, 28 does not act directly on the inner portion of the internal gear member 22, the thickness of the internal gear member 22 can be reduced, and the radial size is reduced. can do.

  Other advantages of the gear transmission 100 will be described. As shown in FIGS. 1 and 2, the axial length of the internal tooth pin 20 is equal to the axial length of the internal tooth member 22. For example, when the projection is provided on the inner periphery of the support member as in the above-described conventional gear transmission and the projection is brought into contact with the inner periphery of the internal gear to position the support and the internal gear, the internal gear It is necessary to make the axial length of the pin shorter than the axial length of the internal gear member. Further, in the conventional gear transmission, the thickness of the external gear becomes thinner as the axial length of the internal tooth pin becomes shorter. In the gear transmission 100, since it is not necessary to make the axial length of the internal tooth pin 20 shorter than the axial length of the internal tooth member 22, the thickness of the external gear 18 can be increased. By thickening the thickness of the external gear 18, the meshing area of the external gear 19 and the internal gear 24 becomes large, and a large torque can be output.

Second Embodiment
The gear transmission 200 will be described with reference to FIGS. 4 and 5. The gear transmission 200 is a modification of the gear transmission 100. The description of the gear transmission 200 may be omitted by assigning the same reference numeral or the same reference numeral to the lower two digits to the same component as the gear transmission 100. The gear transmission 200 differs from the gear transmission 100 in the structure of the positioning portion.

  The gear transmission 200 includes a support member 226 having a through hole 226a, an internal tooth member 222 having a through hole 222a and constituting an internal gear 224, and a support member 228 having a through hole 228a. That is, the gear transmission 200 differs from the gear transmission 100 in the structure of the case. The through holes 226a, 222a and 228a are in communication. In the gear transmission 200, no oil seal is disposed between the support member 228 and the second plate 6c (see also FIGS. 1 and 2).

  The support member 226 and the support member 228 have the same outer diameter. The outer diameter of the support members 226, 228 is larger than the outer diameter of the internal gear member 222. Further, at the radial direction end of the support members 226, 228, first protrusions 226b, 228b extending toward the axis 34 are provided. Furthermore, second protrusions 226 c and 228 c extending along the axis 34 are provided at the end of the support members 226 and 228 in the direction of the axis 34. The second protrusions 226 c and 228 c surround both ends in the direction of the axis 34 of the internal gear member 222, and are in contact with the outer peripheral surface of the internal gear member 222. That is, both ends of the internal gear member 222 are supported by the second protrusions 226 c and 228 c. The second protrusions 226 b and 228 c are an example of a positioning unit. In the case of the gear transmission 200, even when a force is applied from the carrier 6 in the radial direction of the support members 226, 228, the force can be suppressed from being applied to the outer peripheral side of the internal gear member 222.

  As described above, the gear transmissions 100 and 200 are provided with positioning portions (protrusions 22 b, 22 c, 226 c and 228 c) at radial end portions. However, the technology disclosed in the present specification can also be applied to a gear transmission in which the positioning portion is provided at a position other than the radial end. With reference to FIG. 3, the position where the positioning portion can be provided will be described.

  As described above, FIG. 3 shows the second plate 6c observed in the arrow A1 direction. The imaginary line 50 indicates a circle in contact with the end on the side (radially inner side) close to the axis 34 of the through hole (bolt hole) 28 a. The positioning portions of the support member and the internal tooth member can be provided at any position as long as they are radially outside of the imaginary line 50. For example, when the positioning portion is provided between the through holes 28a and 28a, a protrusion extending toward the support members 26 and 28 is provided on the end face 22 of the internal tooth member in the direction of the axis 34, and the support member 26 corresponding to the protrusion , 28 may be provided with a groove, and the protrusion may be inserted into the groove. Further, a protrusion extending toward the inner tooth member 22 is provided on the end face of the support members 26 and 28 in the direction of the axis 34, a groove is provided on the end face of the inner tooth member corresponding to the protrusion, and the protrusion is provided in the groove You may insert it.

  In addition, in order to prevent that a lubricant etc. flow out from the inside of a gear transmission, you may apply a sealing agent to the surface which a support member and an internal gear member contact. In addition, an O-ring groove may be formed on the inner side of the imaginary line 50 for arranging the O-ring on the support member and / or the internal tooth member. By disposing the O-ring between the support member and the internal tooth member inside the bolt hole 28a (the imaginary line 50), the outflow of the lubricant and the like can be more reliably prevented.

  As mentioned above, although the specific example of this invention was described in detail, these are only an illustration and do not limit a claim. The art set forth in the claims includes various variations and modifications of the specific examples illustrated above. The technical elements described in the present specification or the drawings exhibit technical usefulness singly or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the techniques illustrated in the present specification or the drawings simultaneously achieve a plurality of purposes, and achieving one of the purposes itself has technical utility.

6: Carrier 18: External gear 22: Internal tooth member 22a: Bolt hole 22b: Positioning portion 22c: Positioning portion 24: Internal gear 26: Support member 26a: Bolt hole 28: Support member 28a: Bolt hole 34: Rotation axis 100: Gear transmission

Claims (3)

An internal gear member provided with an internal gear on its inner periphery;
An external gear having a number of teeth different from the number of teeth of the internal gear and meshing with the internal gear,
A carrier that supports an external gear and can rotate relative to the internal gear;
And a support member disposed on both sides of the internal gear member in the rotational axis direction of the carrier and rotatably supporting the carrier.
The internal tooth member and the support member are provided with bolt holes through which the bolts securing them pass.
The bolt holes extend along the rotation axis, and a plurality of bolt holes are provided around the rotation axis,
A positioning portion for positioning in the radial direction between the internal tooth member and the support member is provided outside the radial direction with respect to a circle connecting the end portions of the bolt holes located on the rotary shaft side in the radial direction.
A gear transmission in which the material of the support member is stronger than the material of the internal gear member.   The gear transmission according to claim 1, wherein the positioning portion is provided at a radial end of the internal gear member. The radial end of the internal gear member is located outside the radial end of the support member,
The gear transmission according to claim 2, wherein the radial end of the internal gear member is provided with a protrusion which extends toward the support member and contacts the end of the support member.

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