JP2013160243A - Gear device including hollow part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To regulate the axial movement of a cylindrical body relative to an outside member more reliably, while enabing retro-fitting of the cylindrical body constituting a hollow part.SOLUTION: A gear device 30 includes a hollow part 31. The hollow part 31 is structured of a cylindrical body 76, and the cylindrical body 76 is axially fixed to a second carrier 42, which is disposed radially outside of the cylindrical body 76, through a ring-like member 80. The cylindrical body 76 and the second carrier 42 respectively include a step part 77 and a step part 42A having shoulder parts 76B, 76C which abut on the ring-like member 80 in the axial direction. In the ring-like member 80, the axial rigidity thereof is higher than the radial rigidity thereof.

Description

  The present invention relates to a gear device having a hollow portion.

  Patent Document 1 discloses a gear device 16 having a hollow portion 14 at the radial center as shown in FIGS. 8 and 9.

  The hollow portion 14 is configured by a cylindrical body 18. The cylindrical body 18 is fixed to a pair of first and second carriers 20 and 22 disposed on the outer side in the radial direction. The first and second carriers 20 and 22 are connected via carrier pins 20A and bolts 21 integrated with the first carrier 20.

  The first carrier 20 has a stepped portion 20B. The cylindrical body 18 is restricted from moving to one side in the axial direction (left side in FIG. 8) by abutting one end side thereof on the stepped portion 20B.

  On the other hand, as shown in FIG. 9, the second carrier 22 has an outer groove 22A formed on the inner peripheral surface thereof. An inner groove 18 </ b> A is formed on the outer peripheral surface of the cylindrical body 18 so as to face the outer groove 22 </ b> A of the second carrier 22. An O-ring 24 is disposed in the outer groove 22A and the inner groove 18A so as to straddle the outer groove 22A and the inner groove 18A. The O-ring 24 restricts the axial movement of the cylindrical body 18 with respect to the second carrier 22 (particularly movement to the other side in the axial direction).

  According to the configuration of Patent Document 1, since the elasticity of the O-ring 24 is used for assembling the cylindrical body 18, the cylindrical body 18 can be assembled by “retrofitting” after each member of the gear device 16 is assembled. In addition, the movement of the cylindrical body 18 in the axial direction can be restricted by the outer groove 22A, the inner groove 18A, and the O-ring 24.

JP 2011-185318 A

  However, since the incorporation of the cylinder 18 in Patent Document 1 utilizes the elastic deformation of the O-ring 24, the O-ring 24 is elastically deformed even after the incorporation, and therefore the cylinder 18 is the cylinder 18. There is a problem that the first carrier 20 and the second carrier 20 and 22 supporting the carrier easily move minutely in the axial direction.

  Furthermore, in the configuration according to Patent Document 1, since it is necessary to incorporate the cylindrical body 18 while elastically deforming the O-ring 24 when the cylindrical body 18 is assembled, the axial direction of the outer groove 22A and the inner groove 18A. In setting the width L1, it is necessary to secure extra deformation allowances δ1 to δ3 of the O-ring 24. For this reason, the O-ring 24 itself moves in the axial direction in the outer groove 22A and the inner groove 18A. As a result, the cylindrical body 18 also becomes easier to move in the axial direction.

  The present invention has been made in order to solve such a conventional problem, and enables the cylinder constituting the hollow portion to be retrofitted and ensures the axial movement of the cylinder relative to the outer member. It is an object of the present invention to provide a gear device having a hollow portion that can be regulated (or to increase the positioning accuracy of the cylinder).

  The present invention is a gear device having a hollow portion, and the hollow portion is constituted by a cylindrical body, and the cylindrical body is fixed in an axial direction via a fixing member to an outer member arranged on the radially outer side thereof. The cylindrical body and the outer member each have a step portion that contacts the fixing member in the axial direction, and the fixing member has a configuration in which the axial rigidity is higher than the radial rigidity. Thus, the above problem is solved.

  In the present invention, when fixing the cylindrical body to the outer member arranged on the outer side in the radial direction, the cylindrical body and the outer member are formed with stepped portions that contact the fixing member in the axial direction, and the fixing member has a diameter. A member having a higher axial rigidity than a directional rigidity is used.

  As a result, the cylindrical body can be retrofitted into the outer member by utilizing the “radial deformability” of the fixing member having low rigidity. Using the “deformability”, the axial positioning with respect to the outer member of the cylinder can be accurately maintained.

  Further, since the deformation of the fixing member when the cylindrical body and the fixing member are incorporated can be performed mainly only by the radial deformation of the fixing member, basically, the deformation allowance of the fixing member is almost secured in the axial direction. There is no need, and in this respect as well, minute movement in the axial direction of the cylinder can be reliably suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, while enabling the retrofit of the cylinder which comprises a hollow part, it can control more reliably the movement of the axial direction with respect to the outer member of a cylinder (or raises the positioning accuracy of a cylinder more). it can.

Sectional drawing of the principal part of the gear apparatus which concerns on an example of embodiment of this invention. In the above embodiment, (A) an enlarged cross-sectional view (including a partial enlarged cross-section in part), and (B) an arrow IIB-IIB line showing a state when the cylindrical body is incorporated into the outer member together with the fixing member. Cross section along (A) Enlarged sectional view (partially including a partially enlarged cross section) showing the state after the cylindrical body is incorporated in the outer member together with the fixing member in the above embodiment, and (B) its arrow IIIB-IIIB line Sectional view along Whole sectional view showing a state in which the gear device is used Right side view of FIG. The partial expanded sectional view concerning an example of other embodiments of the present invention. (A) principal part expanded sectional view of the gear apparatus which concerns on an example of further another embodiment of this invention, (B) The expanded sectional view of the arrow VIVII part, (C) Sectional drawing which shows the modification Sectional drawing which shows an example of the conventional gear apparatus The principal part expanded sectional view of FIG.

  Hereinafter, an example of an embodiment of the present invention will be described in detail based on the drawings.

  FIG. 1 is a cross-sectional view of a main part of a gear device 30 according to an example of an embodiment of the present invention. 4 is an overall cross-sectional view showing a state in which the gear device 30 is used, and FIG. 5 is a right side view of FIG.

  First, the overall configuration of the gear device 30 will be described with reference to FIGS. 1, 4, and 5.

  The gear device 30 is used for driving a joint 33 of an industrial robot (not shown) together with a motor (not shown), and includes a so-called sort-type eccentric oscillating speed reduction mechanism 32. . In this gear device 30, the external gears 38 and 39 are oscillated and rotated by the synchronous rotation of one drive eccentric shaft 34 and two driven eccentric shafts 35 and 36 (see FIG. 5). Internally meshing with the internal gear 40.

  The outline of the power transmission system will be described. An opening 44A for allowing a motor pinion (not shown) to face is formed in the casing cover (= second arm described later) 44. A motor pinion (not shown) is engaged with the input gear 46. The input gear 46 is fixed to the drive eccentric body shaft 34 via a spline 47. Drive eccentric bodies 48 and 49 are formed integrally with the drive eccentric body shaft 34. The drive eccentric bodies 48 and 49 are fitted in the eccentric body holes 38A and 39A of the external gears 38 and 39 via rollers 51 and 52, respectively. In addition, eccentric gear holes 38B, 39B, 38C, and 39C through which the two driven eccentric shafts 35 and 36 pass are formed in the external gears 38 and 39 (see FIG. 5). The driven eccentric body shafts 35 and 36 are integrally formed with driven eccentric bodies 57 and 58 (the driven eccentric body on the driven eccentric body shaft 36 side is not shown).

  The drive eccentric bodies 48 and 49 and the driven eccentric bodies 57 and 58 have different outer diameters, but have the same eccentricity e, and the eccentric bodies 48 and 57 at the same position in the axial direction of the eccentric body shafts 34 to 36. The eccentric phases of each other or the eccentric bodies 49 and 58 are also aligned. As a result, when the drive eccentric body shaft 34 rotates, the external gears 38 and 39 swing, and the driven eccentric body shafts 35 and 36 rotate by this swing. As a result, the external gears 38 and 39 are rotated. Each can be stably swung and rotated while being supported at three locations in the circumferential direction.

  Each external gear 38, 39 is in mesh with the internal gear 40. The internal gear 40 includes an internal gear main body 40A integrated with the casing 70, and an external pin 40B that is rotatably supported by the internal gear main body 40A and forms internal teeth of the internal gear 40. . The number of external teeth of the external gears 38 and 39 is slightly smaller (by 1 in this example) than the number of internal teeth of the internal gear 40 (the number of external pins 40B). Therefore, when the external gears 38 and 39 swing once while being inscribed in the internal gear 40, the external gears 38 and 39 rotate relative to the internal gear 40 by one tooth (rotate). The eccentric shafts 34 to 36 are supported by the pair of first and second carriers 41 and 42 by the relative rotation of the external gears 38 and 39 with respect to the internal gear 40, and around the axis O1 of the gear device 30. Revolve. Revolution of each of the eccentric body shafts 34 to 36 is taken out as the rotation (rotation) of the pair of first and second carriers 41 and 42. The first and second carriers 41 and 42 are axially and circumferentially driven by carrier pins (not shown: equivalent to the carrier pins 20A in the conventional configuration of FIG. 8) passing through the external gears 38 and 39. It is connected. Therefore, the first and second carriers 41 and 42 rotate integrally as a large output body.

  In this embodiment, a casing 70 integrated with an internal gear main body 40A is fixed via a first arm (base member) 72 and a bolt 69 of an industrial robot (the whole is not shown). Further, the second carrier 42 is fixed to the second arm 44 of the industrial robot (integrated with the casing cover) and the bolt 73. Therefore, the second arm 44 can be rotated relative to the first arm 72 by eventually rotating the drive eccentric body shaft 34 by the rotation of the motor.

  Here, the support structure of the cylinder 76 will be described.

  The gear device 30 has a hollow portion 31 for inserting a wire harness 78 for robot control at the center in the radial direction. The hollow portion 31 is configured by a cylindrical body 76. The cylindrical body 76 is fixed in the axial direction via a ring-shaped member (fixing member) 80 to the pair of first and second carriers 41 and 42 (outer member) disposed on the outer side in the radial direction. As described above, the pair of first and second carriers 41 and 42 are integrally connected to each other in the axial direction and the circumferential direction by carrier pins (not shown). For this reason, the pair of first and second carriers 41 and 42 (in the form of two members) jointly support the cylindrical body 76 in this embodiment as “first and second members of the outer member”. It is functioning.

  The first carrier 41 (which is the first member of the outer member) has a step portion 41A perpendicular to the shaft on the inner peripheral side. The cylindrical body 76 is restricted from moving toward one side (left side in FIG. 1) in the axial direction of the cylindrical body 76 by the end portion 76A coming into contact with the stepped portion 41A. The step portion 41A is not “a step portion with which the ring-shaped member (fixing member) 80 abuts”, and therefore does not correspond to the “step portion” described in claim 1. In the present embodiment, the present invention is applied to the movement restriction to the other side in the axial direction described below.

  2 and 3, the second carrier 42 (which is the second member of the outer member) has a stepped portion (shoulder portion) 42A that abuts the side surface of the ring-shaped member 80 in the axial direction. ing. More specifically, the step portion 42 </ b> A includes a single shoulder portion whose surface facing the first carrier 41 side is a contact surface that contacts the ring-shaped member 80. In addition, the cylindrical body 76 includes a stepped portion 77 having a pair of shoulder portions 76B and 76C with which the ring-shaped member 80 abuts on both sides in the axial direction. The pair of shoulder portions 76B and 76C are formed so as to face each other with the ring-shaped member 80 interposed therebetween, and jointly constitute a single recess (the ring-shaped member 80 abuts on both sides in the axial direction). . That is, the stepped portion 77 is constituted by a concave portion into which the ring-shaped member 80 is inserted. Note that, in the stepped portion 77, the shoulder portion 76B actually contributes to the axial movement restriction of the cylindrical body 76.

  The ring-shaped member 80 is made of metal in this embodiment. The ring-shaped member 80 has higher axial rigidity than radial rigidity. In this embodiment, this characteristic is realized by “a shape in which the cross section is rectangular and the slit 82 is partly in the circumferential direction”. That is, the presence of the slit 82 allows the ring-shaped member 80 to be easily elastically deformed in the radial direction. Specifically, the outer diameter and inner diameter of the ring-shaped member 80 are further increased by compressing and compressing the ring-shaped member 80 in the radial direction so as to reduce the distance between the faces 80A and 80B facing each other across the slit 82. Can be small. Conversely, the outer diameter and the inner diameter of the ring-shaped member 80 are made larger by pulling the ring-shaped member 80 in the radial direction and elastically deforming the surfaces 80A and 80B facing each other with the slit 82 therebetween. Can do. However, since the ring-shaped member 80 is made of metal, it does not basically deform in the axial direction (the axial rigidity is higher than the radial rigidity).

  With reference to FIG. 2, the rigidity (or elasticity) characteristics of the ring-shaped member 80 will be described more specifically. In this embodiment, the outer diameter d1 of the bottom 77A of the stepped portion 77 of the cylindrical body 76 is described. Is set so that the relationship that the ring-shaped member 80 is smaller than the inner diameter D1 of the ring-shaped member 80 when the ring-shaped member 80 is contracted to the size of the outer diameter d2 of the cylindrical body 76 is established (for incorporation) As an essential requirement, if the outer diameter d1 of the bottom 77A is smaller than the minimum inner diameter (not shown in FIG. 2) of the ring-shaped member 80 when the ring-shaped member 80 is contracted to the minimum inner diameter D4 of the second carrier 42. Enough). The minimum inner diameter D4 of the second carrier 42 means a portion of the second carrier (outer member) 42 having the minimum inner diameter among the portions through which the ring-shaped member 80 passes when the cylindrical body 76 is assembled. . At the same time, as shown in FIG. 3, the outer diameter (outer diameter of the shoulder portion of the stepped portion 77) d2 of the cylindrical body 76 is larger than the inner diameter D2 when the ring-shaped member 80 is released.

  An inclined portion 42T is formed on the inner periphery in the vicinity of the end portion 42F of the second carrier 42 (which is the second member of the outer member). The maximum inner diameter D3 of the inclined portion 42T is larger than the outer diameter d4 in the released state of the ring-shaped member 80. The inclined portion 42T is linearly inclined so that the maximum inner diameter D3 decreases to the minimum inner diameter D4 of the stepped portion 42A of the second carrier 42 as the gear device 30 moves inward in the axial direction.

  Returning to FIG. 1, an oil seal 84 for sealing the lubricant in the gear device 30 is disposed between the cylinder 76 and the second arm 44 of the industrial robot (also used as a casing cover). Yes. Further, an O-ring 86 is disposed between the first carrier 41 and the cylinder 76.

  Next, the operation of the gear device 30 according to this embodiment will be described.

<Power transmission>
When the input gear 46 rotates due to rotation of a motor (not shown), the drive eccentric body shaft 34 rotates via the spline 47 and the external gears 38 and 39 swing via the drive eccentric bodies 48 and 49. As the external gears 38 and 39 swing, the driven eccentric body shafts 35 and 36 rotate, and as a result, the eccentric body shafts 34 to 36 rotate in synchronization. As a result, the eccentric gears 48 and 57 oscillate the external gear 38 in the same axial position as the eccentric bodies 48 and 57, and the eccentric bodies 49 and 58 are in the same axial position as the eccentric bodies 49 and 58. The external gear 39 is swung.

  Since the number of teeth of the external gears 38 and 39 is one less than the number of teeth of the internal gear 40 (the number of external pins 40B), the external gears 38 and 39 each time the drive eccentric body shaft 34 rotates once. Is shifted in the circumferential direction by one tooth with respect to the internal gear 40 (rotates). Due to the rotation of the external gears 38 and 39, the three eccentric body shafts 34 to 36 revolve around the axis O1 of the gear device 30 and support the eccentric body shafts 34 to 36. The two carriers 41 and 42 rotate integrally. As a result, the second arm 44 fixed to the second carrier 42 can be rotated relative to the first arm 72 of the industrial robot fixed to the casing 70.

<Incorporation of cylinder 76>
At the center in the radial direction of the first and second carriers 41, 42, a hollow portion 31 constituted by a cylindrical body 76 is formed. For this reason, the wire harness 78 for industrial robot control can be inserted into the hollow portion 31. The cylindrical body 76 is arranged on the radially outer side (corresponding to the first and second members of the outer member) with the ring-shaped member (fixing member) 80 fitted therein, the first and second carriers 41, 42 will be incorporated later. Hereinafter, this operation will be described.

  The ring-shaped member 80 according to the present embodiment is formed of a metal member having a rectangular cross section and a slit 82 provided in a part of the circumferential direction. Therefore, the ring-shaped member 80 can be easily deformed in the radial direction.

  More specifically, in the present embodiment, as shown in FIG. 2, the ring-shaped member 80 is replaced with the outer diameters of the shoulder portions 76 </ b> B and 76 </ b> C of the stepped portion 77 of the cylindrical body 76 (= the outer diameter of the cylindrical body 76). The bottom portion 77A of the step portion 77 (formed by the pair of shoulder portions 76B and 76C) of the cylindrical body 76 when the inner diameter of the ring-shaped member 80 when radially contracted to a diameter smaller than d2 is D1. The outer diameter d1 is set to be smaller than the inner diameter D1. Furthermore, the outer diameter d2 of the shoulder portions 76B and 76C of the cylindrical body 76 is set to be larger than the inner diameter D2 when the ring-shaped member 80 is released. Therefore, the cylindrical body 76 can be retrofitted by the following procedure.

  First, by expanding the ring-shaped member 80 in the radial direction, the inner diameter of the ring-shaped member 80 is made larger than the outer diameter d2 of the cylindrical body 76, and the ring-shaped member 80 is fitted into the stepped portion 77 of the cylindrical body 76. Then, the entire cylindrical body 76 is incorporated into the second carrier 42 from the right side of FIG. 2 while the ring-shaped member 80 is fitted in the stepped portion 77.

  In FIG. 2, the operator presses the ring-shaped member 80 from the outside in the radial direction to reduce the diameter until the outer diameter matches the outer diameter of the cylindrical body 76 (outer diameters of the shoulder portions 76B and 76C) d2. Further, the state in which the cylinder 76 is assembled into the second carrier 42 is shown. However, in the present embodiment, as shown in FIG. 3, an inclined portion 42 </ b> T is formed in the vicinity of the end portion 42 </ b> F of the second carrier 42. The inclined portion 42T has an inner diameter D3 larger than the outer diameter d4 when the ring-shaped member 80 is released at the end portion 42F, and the step portion 42A of the stepped portion 42A progresses inward in the axial direction of the gear device 30 from the end portion 42F. It inclines so that it may become small to the minimum internal diameter D4. Therefore, since the ring-shaped member 80 is automatically reduced in diameter from the released state only by moving the cylindrical body 76 with the ring-shaped member 80 in the axial direction along the inclined portion 42T, such a worker It is not always necessary to reduce the diameter in advance (in other words, in the case where the inclined portion 42T is not formed, the cylinder 76 with the operator intentionally reducing the diameter of the ring-shaped member 80). Need to be incorporated).

  Eventually, when the ring-shaped member 80 fitted into the cylindrical body 76 exceeds the stepped portion 42A of the second carrier 42, as shown in FIG. At the same time, the reduced diameter of the ring-shaped member 80 is released. As a result, the outer diameter of the ring-shaped member 80 becomes larger than the minimum inner diameter D4 of the step portion 42A of the second carrier 42. In the present embodiment, even when the ring-shaped member 80 is released, the inner diameter D2 when the ring-shaped member 80 is released is smaller than the outer diameter d2 of the cylindrical body 76. .

<Restriction of axial movement of cylinder 76>
When the assembly of the cylindrical body 76 into the first and second carriers 41 and 42 is completed in this way, first, the end portion 76A of the cylindrical body 76 comes into contact with the stepped portion 41A of the first carrier 41. As a result, the movement of the cylindrical body 76 to one side in the axial direction (left side in FIG. 1) is restricted.

  Second, the second carrier 42 has a stepped portion 42A with which the ring-shaped member 80 abuts. The stepped portion 42A is integrated with the cylindrical body 76 and the stepped portion 77 in the axial direction. In addition, when the ring-shaped member 80 "that hardly deforms in the axial direction (high rigidity) abuts, the movement of the cylindrical body 76 to the other side in the axial direction (the right side in FIG. 1) is restricted (this embodiment). Peculiar action).

  That is, as a result, the movement of the cylindrical body 76 is reliably restrained by the first and second carriers 41 and 42 which are outer members on either side in the axial direction.

<Operations and effects obtained by restraining the axial movement of the cylinder 76>
In the present embodiment, an oil seal 84 is interposed between the cylinder 76 and the second carrier 42. An O-ring 86 is interposed between the first carrier 41 and the cylindrical body 76.

  The oil seal 84 is designed in consideration of a corresponding life with respect to sliding in the rotational direction. However, if axial sliding is added in addition to sliding in the rotational direction, it tends to cause early deterioration. The O-ring 86 is a sealing member that is used when there is no relative rotation or relative movement between the two members (in this example, the first carrier 41 and the cylindrical body 76). If 41 and the cylinder 76 move relative to each other in the axial direction, there is a risk that lubricant leakage will occur earlier than expected.

  However, in the present embodiment, the axial relative movement (small displacement) between the cylinder 76 and the first and second carriers 41 and 42 is suppressed to a minimum as compared with the conventional case. Early deterioration (early lubricant leakage) of the ring 86 can be reliably prevented.

  In this type of gear device 30, depending on the design, an encoder, a positioning sensor (not shown), or the like may be incorporated in the cylinder 76, and in this case, the cylinder 76 particularly has the second carrier 42. On the other hand, being immovable in the axial direction also leads to stable operation of the sensors.

<Other effects>
Furthermore, for example, when the stepped portions of the cylindrical body 76 and the second carrier 42 are both recessed portions having a pair of shoulder portions, the second carrier 42 and the cylindrical body 76 cannot be disassembled during maintenance. However, in this embodiment, since the step portion 42A on the second carrier 42 side is a single shoulder portion, the cylindrical body 76 is disassembled when the second carrier 42 is disassembled when the gear device 30 is disassembled for maintenance. Both the second carrier 42 and the first carrier 41 can be disassembled, ensuring ease of maintenance and completeness.

  Next, FIG. 6 shows an example of another embodiment that further considers the merit of disassembly during maintenance.

  In the embodiment shown in FIG. 6, both of the “stepped portion in contact with the fixing member in the axial direction” formed in the outer member and the cylindrical body are configured by a single shoulder portion. That is, the difference from the previous embodiment is that the step 90A of the cylindrical body 90 is not a recess. Specifically, it is constituted by a single shoulder portion facing in the direction facing the step portion 42A on the second carrier 42 side.

  The ring-shaped member 91 is sandwiched between the step portion 90A of the cylindrical body 90 and the step portion 42A of the second carrier 42, thereby positioning the cylindrical body 90 in the axial direction with respect to the first and second carrier bodies 41 and 42. Do. Even in this case, it is possible to incorporate the cylindrical body 90 by retrofitting by utilizing the elastic deformation in the radial direction of the ring-shaped member 91, and the cylindrical body 90 is pivoted due to the axial rigidity of the ring-shaped member 91. The predetermined effect of the present invention can be obtained in that it hardly moves in the direction. Then, according to the configuration according to this embodiment, the cylindrical body 90 is attached to either the first carrier 41 or the second carrier 42 only by disassembling one of the first carrier 41 and the second carrier 42. Can be disassembled.

  In the embodiment of FIG. 6, the degree to which the minute movement of the cylinder 90 in the axial direction can be suppressed depends on the manufacturing error of the entire apparatus including the cylinder 90. Therefore, in order to implement this configuration more practically, for example, a plurality of ring-shaped members 91 having slightly different axial lengths are prepared in advance, and the gear device (30) is assembled when the cylindrical body 90 is assembled. The ring-shaped member 91 having the optimum axial length may be selected from the plurality of prepared ring-shaped members 91. Thereby, acquisition of the effect of this invention and the flexibility of manufacture can be made compatible.

  The shape of the fixing member in the present invention is not limited to the shape as in the above embodiment. The material does not necessarily need to be a metal.

  FIG. 7 shows another configuration example of the fixing member.

  7A and 7B show a resin U-shaped ring (ring-shaped member) 92 that can function as a fixing member of the present invention. The U-shaped ring 92 includes a stepped portion (concave portion) 95 including a pair of shoulder portions 94A and 94B of the cylindrical body 94 and a stepped portion (concave portion) including a pair of shoulder portions 96A and 96B of the second carrier 96. No. 97 is the axial dimension that just fits and abuts.

  As shown in FIG. 7B, the U-shaped ring 92 has a substantially U-shaped cross section with one side in the axial direction being an open end and the other side being a closed end. is there. The outer diameter d5 on the open end side of the U-shaped ring 92 is larger than the outer diameter d6 on the closed end side, and the outer diameter is substantially linear from d5 to d6 from the position P1 slightly shifted from the open end toward the closed end side. It is getting smaller. Further, the inner diameter D5 on the open end side is smaller than the inner diameter D6 on the closed end side. That is, the open end side has a larger outer diameter (d5> d6) and a smaller inner diameter (D5 <D6) than the closed end side. Further, the inner side of the U-shape of the U-shaped ring 92 has a shape in which a cylindrical hollow portion 92A and a conical hollow portion 92B are continuous from the opening end side.

  In addition, the portions of the U-shaped ring 92 that are in contact with the shoulder portions 94A and 94B of the cylindrical body 94 and the shoulder portions 96A and 96B of the second carrier 96 at both ends in the axial direction of the U-shape are planes 92C perpendicular to the axis. 92D and planes 92E, 92F, and a large contact area with the shoulder portions 94A, 94B, 96A, 96B is secured.

  With this configuration, the U-shaped ring 92 compresses the outer diameter (d5) on the opening end side by crushing the opening end side from the radial direction (the opening dimension L5 on the opening end side is reduced to the outside on the closing end side). As a result, the diameter can be reduced to the minimum inner diameter of the shoulder 96B (low in elasticity in the radial direction). Therefore, coupled with the presence of the inclined portion 96T, the cylindrical body 94 can be incorporated into the second carrier 96 later.

  Further, since the U-shaped ring 92 is made of resin and hardly deforms with respect to a compressive load, the U-shaped ring 92 has high axial rigidity and minimal axial deformation (diameter The axial stiffness is higher than the directional stiffness). Therefore, even with such a U-shaped ring (ring-shaped member) 92, it is possible to obtain the predetermined effects of the present invention such that the second carrier 96 and the cylindrical body 94 do not slightly move in the axial direction.

  FIG. 7C shows still another modification of the U-shaped ring.

  This U-shaped ring 98 is also formed of resin. The U-shaped ring 98 has a cylindrical hollow portion 98A and a conical hollow portion 98B equivalent to the U-shaped ring 92 of FIG. 7A, but the outer shape is different from the U-shaped ring 92.

  Specifically, the U-shaped ring 98 has large arc-shaped chamfered portions 98A to 98D on the inner periphery and outer periphery on the opening end side and on the inner periphery and outer periphery on the closed end side. As for the radius of curvature of the chamfer, the radius of curvature of the chamfered portions 98A and 98B on the open end side of the U-shape is slightly smaller than the radius of curvature of the chamfered portions 98C and 98D on the closed end side. The U-shaped ring 98 also has flat surfaces 98E to 98H that are perpendicular to the shafts that abut the shoulder portions 94A and 94B of the cylindrical body 94 and the shoulder portions 96A and 96B of the second carrier 96 at both ends in the axial direction. ing. Further, the U-shaped ring portion 98 includes a plane 98J parallel to an axis contacting the bottom surface 95A of the step portion (recess portion) 95 of the cylindrical body 94, and a bottom surface 97A of the step portion (recess portion) 97 of the second carrier 96. It also has a flat surface 98K parallel to the abutting axis.

  Thus, when the cylinder 94 is about to move in the axial direction with respect to the second carrier 96, the U-shaped ring 98 has the shoulder portions 94 A and 94 B and the bottom surface 95 A of the cylinder 94 and the shoulder of the second carrier 96. The reaction force can be effectively received from the portions 96A and 96B and the bottom surface 97A, and as a result, the characteristic that the axial deformation is difficult (the axial rigidity is higher than the radial direction) is obtained.

  7A and 7B, unlike the previous embodiment, the pair of shoulder portions 94A and 94B of the cylindrical body 94 that abuts the U-shaped rings 92 and 98, and the second carrier 96. The pair of shoulder portions 96A and 96B constitute step portions (recess portions) 95 and 97 into which the U-shaped rings 92 and 98 are just inserted. For this reason, even if the first carrier 41 or the second carrier 96 is disassembled during maintenance, the cylinder 94 cannot be separated from the second carrier 96 as it is because of the presence of the (U-shaped ring 92 or 98). However, since the U-shaped rings 92 and 98 of the embodiment of FIG. 7 are formed of “resin”, if necessary, by applying a strong axial impact force to the cylinder 94, the cylinder 94 and Only the U-shaped rings 92 and 98 can be broken without damaging the second carrier 96, whereby the cylindrical body 94 and the second carrier 96 can be disassembled. When reassembling the cylinder 94, the broken U-shaped ring (92, 98) may be removed from the recesses 95, 97 to prepare a (new) U-shaped ring 92, 98.

  Other configurations are the same as those of the embodiment already described, and thus redundant description is omitted.

  In this way, the fixing member having higher axial rigidity than radial rigidity can be realized by devising its shape with a material such as metal or resin, and is limited to the configuration examples listed here. Not. For example, the ring-shaped member 80 may be formed of resin, and the U-shaped rings 92 and 98 may be formed of metal. Moreover, it is not necessarily formed of a single material, and for example, a combination of metal and resin may be used. Alternatively, a combination of metal or resin and an elastic member such as rubber may be used. Further, the dimensional relationship between the fixing member and the cylindrical body may be appropriately set, for example, whether or not there is an inclined portion, the depth of the stepped portion, the radial gap between the cylindrical body and the outer member, etc. It is not limited to the configuration example of the form.

  In the present invention, it is not always possible to separate the outer member and the cylindrical body at the time of disassembly.

DESCRIPTION OF SYMBOLS 41 ... 1st carrier 42 ... 2nd carrier 42A ... Step part 76 ... Cylindrical body 76B, 76C ... Shoulder part 77 ... Step part 80 ... Ring-shaped member 82 ... Slit

Claims (8)

A gear device having a hollow part,
The hollow portion is constituted by a cylindrical body,
The cylindrical body is fixed in an axial direction via a fixing member to an outer member arranged on the outer side in the radial direction,
The hollow body and the outer member each have a step portion that abuts the fixing member in the axial direction, and the fixing member has higher axial rigidity than radial rigidity. Gear device having a portion. In claim 1,
The gear member having a hollow portion, wherein the fixing member is a ring-shaped member having a rectangular cross section and a slit in a part of the circumferential direction. In claim 1 or 2,
The outer diameter of the bottom of the step portion of the cylindrical body is smaller than the inner diameter of the fixing member when the outer diameter of the fixing member is contracted in the radial direction to the innermost inner diameter of the outer member,
A gear device having a hollow portion, wherein an outer diameter of a shoulder portion of the step portion of the cylindrical body is larger than an inner diameter when the fixing member is released. In claim 1,
The gear member having a hollow portion, wherein the fixing member is a ring-shaped member having an open end in an axial direction and having a U-shaped cross section. In claim 4,
An opening end side of the U-shape has a larger outer diameter and a smaller inner diameter than the closed end side. In claim 4 or 5,
The gear device having a hollow portion, characterized in that portions of the U-shaped axially opposite ends contacting the stepped portions are flat. In any one of Claims 1-6,
The outer member is constituted by a pair of first and second members connected in the axial direction,
One end of the cylindrical body is fixed in the axial direction by the first member,
The step portion of the cylindrical body is constituted by a concave portion into which the fixing member is inserted,
The step portion of the outer member has a single shoulder portion formed on the second member and facing the first member side. A gear device having a hollow portion. In any one of Claims 1-7,
In the vicinity of the inner peripheral end of the outer member,
A hollow portion characterized in that an inner diameter is larger than an outer diameter at the time of releasing the fixing member, and an inclined portion is formed so that the inner diameter becomes smaller as it advances inward in the axial direction of the gear device. Gear device.

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