JP2017078428A - Change gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure of a change gear for improving concentricity between an internal gear and a planetary carrier.SOLUTION: A first rotary assembly 3 comprises a first rotary shaft member 31 and a sub gear 33 which is rotated together with the first rotary shaft member inside of a casing 2. A second rotary assembly 4 comprises: a planetary carrier 42; a plurality of planetary gears 44 disposed in a circumferential direction inside of the casing and radially outside of the sun gear, supported by the planetary carrier to be rotatable around a planetary axis J2 that is directed along a central axis J1, and including outer peripheral teeth being engaged with outer peripheral teeth of the sun gear and inner peripheral teeth of an internal gear 5; and a second rotary shaft member that is connected to the planetary carrier. A second upper bearing 252 is brought into contact with an outer peripheral surface of the planetary carrier and an inner peripheral surface of the internal gear in a radial direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a transmission.

Conventionally, for example, a planetary transmission disclosed in Japanese Patent Application Laid-Open No. 2012-47325 has been used as a speed reducer or a speed increaser. The transmission disclosed in JP 2012-47325 A includes a first sun gear 34, a first planetary gear 32, a first internal gear 33, and a first carrier 31. The front end portion and the rear end portion of the first carrier 31 are rotatably supported by the housing 4 via two bearings. The intermediate bearing 7 that supports the rear end portion of the first carrier 31 is in contact with the axial end surface of the first internal gear 33.
JP 2012-47325 A

  By the way, in the transmission of Japanese Patent Application Laid-Open No. 2012-47325, the intermediate bearing 7 is not in contact with the first internal gear 33 in the radial direction. Therefore, when the transmission is assembled, It is not easy to improve the coaxiality with the one carrier 31.

  The present invention has been made in view of the above problems, and an object thereof is to improve the coaxiality between an internal gear and a planet carrier.

  An exemplary transmission according to the present invention includes a casing, a first rotary assembly that is rotatably supported by the casing about a central axis, and a rotary that is rotatable about the central axis by a bearing via a bearing. A second rotary assembly that is supported and transmits rotational force to and from the first rotary assembly; an annular internal gear that is fixed to the casing at a radially outer side of the second rotary assembly; The first rotating assembly includes a first rotating shaft member having the central axis positioned at the center, and a sun gear that rotates together with the first rotating shaft member in the casing, and the second rotating assembly. The assembly is arranged in the circumferential direction on the outer side in the radial direction of the sun gear in the casing and in the casing, and the planetary key is centered on the planetary axis that faces the direction along the central axis. A plurality of planetary gears that are rotatably supported by the rear and whose outer peripheral teeth engage with the outer peripheral teeth of the sun gear and the inner peripheral teeth of the internal gear, and are connected to the planet carrier and centered on the central axis A second rotary shaft member positioned at a position where the bearing is in radial contact with the outer peripheral surface of the planet carrier and the inner peripheral surface of the internal gear.

  In the present invention, the coaxiality between the internal gear and the planet carrier can be improved.

FIG. 1 is a longitudinal sectional view of a transmission according to an embodiment. FIG. 2 is a longitudinal sectional view of the transmission. FIG. 3 is a plan view of the second casing and the internal gear. FIG. 4 is a plan view of the internal gear.

  FIG. 1 is a longitudinal sectional view showing a configuration of a transmission 1 according to an exemplary embodiment of the present invention. In FIG. 1, the cross section by the surface containing the central axis J1 of the transmission 1 is shown. FIG. 2 is a longitudinal sectional view showing another section of the transmission 1. The right side of the central axis J1 in FIG. 2 shows a cross section passing through the central axis J1 and the central axis of the bolt 23, and the left side of the central axis J1 shows a cross section passing through the central axis J1 and the central axis of the pin 527. FIG. 3 is a plan view showing the first casing 21 and the internal gear 5. FIG. 4 is a plan view showing the internal gear 5. The transmission 1 is used as a speed reducer or a speed increaser in, for example, a precision processing machine or a 3D measuring device.

  The transmission 1 includes a casing 2, a first rotation assembly 3, a second rotation assembly 4, and an internal gear 5. The casing 2 has a substantially cylindrical shape centered on the central axis J1. The first rotation assembly 3, a part of the second rotation assembly 4, and the internal gear 5 are accommodated in the casing 2. The first rotating assembly 3 is supported by the casing 2 so as to be rotatable about the central axis J1. The second rotating assembly 4 is also rotatably supported by the casing 2 around the central axis J1. The internal gear 5 has an annular shape centered on the central axis J1. The internal gear 5 is located outside the second rotating assembly 4 in the radial direction centered on the central axis J1. In the following description, the radial direction around the central axis J1 is simply referred to as “radial direction”. The internal gear 5 is fixed to the casing 2.

  The casing 2 includes a first casing 21 and a second casing 22. The first casing 21 has a substantially cylindrical shape centered on a central axis J1 that faces in the vertical direction in FIG. The second casing 22 has a substantially cylindrical shape centered on the central axis J1. In the following description, for convenience, the first casing 21 side is described as the upper side and the second casing 22 side is the lower side along the central axis J1, but the direction of the central axis J1 does not necessarily coincide with the direction of gravity. In the following description, the vertical direction, which is the direction in which the central axis J1 faces, is also referred to as “axial direction”.

  The second casing 22 is located below the first casing 21 and faces the first casing 21 in the axial direction. The first casing 21 and the second casing 22 are connected by a plurality of bolts 23. The plurality of bolts 23 are arranged at substantially equal angular intervals in the circumferential direction around the central axis J1. Each bolt 23 extends substantially parallel to the axial direction. Each bolt 23 is a connecting member facing in the axial direction that connects the first casing 21 and the second casing 22. In FIG. 2, only one bolt 23 among the plurality of bolts 23 is illustrated. In the following description, the circumferential direction around the central axis J1 is simply referred to as “circumferential direction”.

  The 1st casing 21 accommodates the 1st rotation assembly 3 in an inside, and supports it rotatably. The 2nd casing 22 accommodates the 2nd rotation assembly 4 inside, and supports it rotatably. The second casing 22 also houses the internal gear 5 inside.

  The internal gear 5 includes a gear part 51 and a bearing support part 52. The gear portion 51 has a substantially annular shape centered on the central axis J1. The bearing support portion 52 is also substantially annular with the central axis J1 as the center. The gear portion 51 is located below the bearing support portion 52. The gear portion 51 and the bearing support portion 52 are a single member. The bearing support portion 52 is not necessarily annular, and may be a discontinuous portion in the circumferential direction in which a plurality of cutout portions are provided intermittently in the circumferential direction, for example. In other words, the bearing support portion 52 may be a set of a plurality of support element portions arranged intermittently in the circumferential direction.

  The outer peripheral surface of the gear portion 51 has a substantially cylindrical shape centered on the central axis J1. The outer peripheral surface of the gear portion 51 is in contact with the inner peripheral surface of the second casing 22 of the casing 2. Thereby, the internal gear 5 is fixed to the second casing 22. The internal gear 5 is fixed to the second casing 22 by, for example, intermediate fitting. In other words, in a state where the internal gear 5 and the second casing 22 are in contact with each other before the internal gear 5 is fixed to the second casing 22, the diameter of the outer peripheral surface of the internal gear 5 is the second casing. The diameter of the inner peripheral surface 22 is substantially the same.

  The inner peripheral surface of the gear portion 51 is substantially cylindrical with the central axis J1 as the center. A plurality of teeth arranged in the circumferential direction are provided on the inner peripheral surface of the gear portion 51. In the following description, the plurality of teeth on the inner peripheral surface of the gear portion 51 are referred to as “inner peripheral teeth”. The inner peripheral surface of the bearing support portion 52 has a substantially cylindrical shape centered on the central axis J1. The upper end surface of the bearing support portion 52 that is the axial end surface of the internal gear 5 is positioned slightly below the upper end surface that is the axial end surface of the second casing 22. For example, the upper end surface of the bearing support portion 52 is positioned about 0.5 mm to 1 mm below the upper end surface of the second casing 22.

  The outer peripheral surface of the bearing support portion 52 includes a cylindrical surface portion 521, a convex surface portion 522, and a flat surface portion 523. The cylindrical surface portion 521 is a part of a cylindrical surface centered on the central axis J1. The convex surface portion 522 protrudes outward in the radial direction from the cylindrical surface portion 521. In the example illustrated in FIG. 4, the outer peripheral surface of the bearing support portion 52 includes four cylindrical surface portions 521, four convex surface portions 522, and four flat surface portions 523. On the outer peripheral surface of the bearing support portion 52, the cylindrical surface portion 521, the convex surface portion 522, and the flat surface portion 523 are arranged in this order in the clockwise direction in FIG.

  A radially inner portion of each cylindrical surface portion 521 of the bearing support portion 52 is a support convex portion 525 that protrudes radially outward from the outer peripheral surface of the gear portion 51. The support convex portion 525 is in contact with the second casing 22 in the axial direction. The contact portion between the support convex portion 525 and the second casing 22 is provided with a rotation prevention portion 526 that is a concave portion and a convex portion that face in the axial direction and engages with each other. In other words, the rotation preventing part 526 is located on the radially inner side of the convex surface part 522. In the example illustrated in FIG. 4, the four support convex portions 525 and the four rotation prevention portions 526 are arranged at substantially equal angular intervals in the circumferential direction. The circumferential position of each rotation prevention unit 526 is different from the circumferential position of each bolt 23 described above. As shown in FIG. 3, each bolt 23 is located on the radially outer side of the cylindrical surface portion 521 of the bearing support portion 52.

  The convex portion of the rotation preventing portion 526 is, for example, a pin 527 that protrudes upward from a surface substantially perpendicular to the axial direction of the second casing 22. As the pin 527, for example, a spring pin having a substantially C-shaped cross section is used. The concave portion of the rotation preventing portion 526 is, for example, a hole provided on the lower surface of the support convex portion 525 of the internal gear 5. Moreover, the convex part of the rotation prevention part 526 may be a pin 527 that protrudes downward from the lower surface of the support convex part 525 of the internal gear 5. In this case, the recess of the rotation prevention unit 526 is, for example, a hole provided on a surface substantially perpendicular to the axial direction of the second casing 22. By inserting the pin 527 into the above-described hole, the relative movement of the internal gear 5 in the circumferential direction with respect to the casing 2, that is, the circumferential shift of the internal gear 5 is prevented.

  The first rotating assembly 3 includes a first rotating shaft member 31 and a sun gear 33. The first rotating shaft member 31 has a substantially cylindrical shape or a substantially columnar shape with the central axis J1 positioned at the center. The sun gear 33 has a substantially cylindrical shape or a substantially columnar shape with the central axis J1 positioned at the center. In other words, the first rotating shaft member 31 and the sun gear 33 are located on the same axis. A plurality of teeth arranged in the circumferential direction are provided on the outer peripheral surface of the sun gear 33. In the following description, the plurality of teeth on the outer peripheral surface of the sun gear 33 are referred to as “outer peripheral teeth”.

  The first rotating shaft member 31 is located inside the first casing 21. The sun gear 33 is connected to the lower end portion of the first rotating shaft member 31 protruding downward from the first casing 21. The sun gear 33 is located inside the second casing 22. The sun gear 33 rotates with the first rotating shaft member 31 in the casing 2. The sun gear 33 may be indirectly connected to the first rotating shaft member 31 via another member, or may be a member connected to the first rotating shaft member 31.

  A first bearing 24 is provided between the outer peripheral surface of the first rotating shaft member 31 and the inner peripheral surface of the first casing 21. The first bearing 24 has a substantially cylindrical shape centered on the central axis J1. The first bearing 24 is located outside the first rotating shaft member 31 in the radial direction. The first rotating assembly 3 is rotatably supported by the first casing 21 of the casing 2 around the central axis J1 via the first bearing 24. The first bearing 24 is, for example, a ball bearing. Various bearings other than a ball bearing may be used as the first bearing 24.

  The second rotating assembly 4 includes a second rotating shaft member 41, a planet carrier 42, a plurality of planet shaft members 43, and a plurality of planet gears 44. The second rotating shaft member 41 has a substantially cylindrical shape or a substantially columnar shape with the central axis J1 positioned at the center. The second rotating shaft member 41 protrudes outward from the casing 2 downward from the lower surface of the second casing 22. The planet carrier 42, the plurality of planet shaft members 43, and the plurality of planet gears 44 are located in the second casing 22.

  The planet carrier 42 includes a carrier shaft part 421 and a planet support part 422. The carrier shaft portion 421 is located below the planet support portion 422. The carrier shaft portion 421 and the planet support portion 422 are a single member. The carrier shaft portion 421 has a substantially cylindrical shape or a substantially columnar shape with the central axis J1 positioned at the center. The planetary support portion 422 has a bottomed and covered substantially cylindrical shape with the central axis J1 positioned at the center. The second rotating shaft member 41 is connected to the lower end portion of the carrier shaft portion 421. The second rotating shaft member 41 and the planet carrier 42 are coaxially positioned with the central axis J1 as the center.

  The planetary support portion 422 includes a support lower surface portion 423, a support side surface portion 424, and a support upper surface portion 425. The support lower surface portion 423 has a substantially disk shape centered on the central axis J1. The support side surface portion 424 has a substantially cylindrical shape centered on the central axis J1. The support upper surface portion 425 has a substantially annular plate shape centered on the central axis J1. The support side surface portion 424 extends upward from the outer peripheral portion of the support lower surface portion 423. The support upper surface portion 425 extends radially inward from the upper end portion of the support side surface portion 424. The support upper surface portion 425 is located at approximately the same position in the axial direction as the bearing support portion 52 of the internal gear 5. The lower end portion of the first rotating shaft member 31 is located in the central opening of the support upper surface portion 425. The sun gear 33 is located inside the planetary support 422. In other words, the sun gear 33 is located on the radially inner side of the support side surface portion 424 between the support lower surface portion 423 and the support upper surface portion 425.

  Each of the plurality of planetary shaft members 43 has a substantially cylindrical shape facing the direction along the central axis J1. The plurality of planetary shaft members 43 have the same shape and the same size. In the following description, the central axis of each planetary shaft member 43 is referred to as “planetary axis J2”. The above-mentioned “direction along the central axis J1” means a direction approximately parallel to the axial direction to which the central axis J1 faces, and does not have to be strictly parallel to the axial direction. That is, the planetary axis J2 of each planetary shaft member 43 may be parallel to the central axis J1, or may be inclined by a small angle with respect to the central axis J1.

  The lower end portion and the upper end portion of each planetary shaft member 43 are fixed to the support lower surface portion 423 and the support upper surface portion 425, respectively. Thereby, each planetary shaft member 43 is fixed to the planet support portion 422 so as not to rotate. The plurality of planetary shaft members 43 are positioned at substantially equal angular intervals in the circumferential direction on the radially outer side of the sun gear 33. In the example shown in FIG. 1, three planetary shaft members 43 are arranged at 120 ° intervals in the circumferential direction. In FIG. 1, only one planetary shaft member 43 among the plurality of planetary shaft members 43 is illustrated. The same applies to the planetary gear 44.

  Each of the plurality of planetary gears 44 is supported by the planetary support portion 422 of the planetary carrier 42 via the plurality of planetary shaft members 43 in the casing 2. That is, the plurality of planetary gears 44 are arranged in the circumferential direction on the radially outer side of the sun gear 33 in the casing 2. In the example shown in FIG. 1, three planetary gears 44 are supported by the planet carrier 42 via three planetary shaft members 43. The plurality of planetary gears 44 are located at approximately the same position in the axial direction as the sun gear 33 and the gear portion 51 of the internal gear 5. In addition, the number and arrangement of the planetary gear 44 and the planetary shaft member 43 may be changed as appropriate.

  Each planetary gear 44 has a substantially cylindrical shape located around the planetary shaft member 43. A plurality of teeth arranged in the circumferential direction are provided on the outer peripheral surface of each planetary gear 44. In the following description, the plurality of teeth on the outer peripheral surface of the planetary gear 44 are referred to as “outer peripheral teeth”. The plurality of planetary gears 44 have the same shape and the same size. A part of the outer peripheral teeth of each planetary gear 44 protrudes outward in the radial direction from a side opening provided in the support side surface portion 424. In other words, a part of the outer peripheral teeth of each planetary gear 44 is located on the radially outer side of the planetary support portion 422. The outer peripheral teeth of the plurality of planetary gears 44 are engaged with the outer peripheral teeth of the sun gear 33 and the inner peripheral teeth of the internal gear 5.

  A planetary bearing 45 is provided between the inner peripheral surface of each planetary gear 44 and the outer peripheral surface of the planetary shaft member 43. The planetary bearing 45 is, for example, a needle bearing. As the planetary bearing 45, various bearings other than the needle bearing may be used. Each planetary gear 44 is rotatably supported by the planetary shaft member 43 around the planetary shaft member 43 via the planetary bearing 45. In other words, each of the plurality of planetary gears 44 is rotatably supported by the planetary carrier 42 around the planetary axis J2 facing the direction along the central axis J1.

  A second lower bearing 251 is provided between the outer peripheral surface of the carrier shaft portion 421 and the inner peripheral surface of the second casing 22. The second lower bearing 251 has a substantially cylindrical shape with the central axis J1 as the center. The second lower bearing 251 is located on the radially outer side of the carrier shaft portion 421. The inner peripheral surface of the second lower bearing 251 is in contact with the outer peripheral surface of the carrier shaft portion 421 in the radial direction. The outer peripheral surface of the second lower bearing 251 is in contact with the inner peripheral surface of the second casing 22 in the radial direction. Thereby, the planet carrier 42 is rotatably supported by the second casing 22 via the second lower bearing 251. The lower end surface of the second lower bearing 251 is in contact with the surface substantially perpendicular to the central axis J1 of the second casing 22 in the axial direction. Thereby, the planet carrier 42 is positioned with respect to the second casing 22 in the axial direction.

  A second upper bearing 252 is provided between the outer peripheral surface of the support upper surface portion 425 of the planetary support portion 422 and the inner peripheral surface of the bearing support portion 52 of the internal gear 5. The second upper bearing 252 has a substantially cylindrical shape centered on the central axis J1. The second upper bearing 252 is located on the radially outer side of the support upper surface portion 425. The inner peripheral surface of the second upper bearing 252 is in contact with the outer peripheral surface of the support upper surface portion 425 of the planet carrier 42 in the radial direction. The outer peripheral surface of the second upper bearing 252 is in contact with the inner peripheral surface of the bearing support portion 52 of the internal gear 5 in the radial direction. Thereby, the planet carrier 42 is rotatably supported by the internal gear 5 via the second upper bearing 252. As described above, since the internal gear 5 is fixed to the second casing 22, the planet carrier 42 is rotatably supported by the second casing 22 via the second upper bearing 252.

  That is, the second rotating assembly 4 is rotatably supported by the casing 2 about the central axis J1 via the second upper bearing 252 and the second lower bearing 251. The second upper bearing 252 and the second lower bearing 251 are, for example, ball bearings. Various bearings other than ball bearings may be used as the second upper bearing 252 and the second lower bearing 251.

  In the example shown in FIG. 1, the upper portion of the second upper bearing 252 protrudes upward from the upper end surface of the planet carrier 42 and the upper end surface of the internal gear 5. The upper outer peripheral surface of the second upper bearing 252 is in contact with the inner peripheral surface of the first casing 21 in the radial direction. The lower end surface that is the axial end surface of the first casing 21 and the upper end surface of the second casing 22 are in contact with each other in the axial direction on the radially outer side of the second upper bearing 252. In the following description, a contact portion between the lower end surface of the first casing 21 and the upper end surface of the second casing 22 is referred to as a “casing boundary portion 26”. At the casing boundary portion 26, the lower end surface of the first casing 21 and the upper end surface of the second casing 22 are in close contact with each other by a fitting structure.

  The casing boundary portion 26 overlaps with the second upper bearing 252 in the radial direction. The axial position of the casing boundary 26 is different from the axial position of the central portion of the second upper bearing 252 in the axial direction. In the casing boundary portion 26, the radially inner end edge overlaps the second upper bearing 252 in the radial direction, and the axial position of the radially inner end edge is the axis of the axial center portion of the second upper bearing 252. It only has to be different from the position in the direction. For example, the radially outer end edge of the casing boundary portion 26 does not necessarily overlap the second upper bearing 252 in the radial direction.

  The ratio of the axial distance between the lower end surface of the second upper bearing 252 and the radially inner end edge of the casing boundary portion 26 with respect to the axial length of the second upper bearing 252 is, for example, 20% or more and 80 % Or less. In the example shown in FIG. 1, the casing boundary portion 26 is located above the central portion in the axial direction of the second upper bearing 252. The ratio of the axial distance between the lower end surface of the second upper bearing 252 and the radially inner end edge of the casing boundary portion 26 with respect to the axial length of the second upper bearing 252 is about 70%.

  The second upper bearing 252 also overlaps the upper end surface that is the axial end surface of the planet carrier 42 in the radial direction. The axial position of the upper end surface of the planet carrier 42 is different from the axial position of the central portion of the second upper bearing 252 in the axial direction. The axial end surface of the planet carrier 42 described above is an axial end surface of a portion of the planet carrier 42 that is in contact with the outer peripheral surface of the second upper bearing 252 in the radial direction. However, the upper end surface of the radially inner portion does not necessarily overlap the second upper bearing 252 in the radial direction.

  The ratio of the axial distance between the lower end surface of the second upper bearing 252 and the axial end surface of the planet carrier 42 with respect to the axial length of the second upper bearing 252 is, for example, 20% or more and 80% or less. It is. In the example shown in FIG. 1, the axial end surface of the planet carrier 42 is positioned above the central portion in the axial direction of the second upper bearing 252. The ratio of the axial distance between the lower end surface of the second upper bearing 252 and the axial end surface of the planet carrier 42 to the axial length of the second upper bearing 252 is about 55%.

  For example, the lower end surface of the second upper bearing 252 is in contact with a surface substantially perpendicular to the central axis J1 of the second casing 22 in the axial direction. Further, the lower end surface of the second upper bearing 252 is in contact with the surface substantially perpendicular to the central axis J1 of the internal gear 5 in the axial direction. A slight gap due to tolerance or the like may exist between the lower end surface of the second upper bearing 252 and the surface of the second casing 22 and the surface of the internal gear 5. For example, the upper end surface of the second upper bearing 252 is in contact with a surface substantially perpendicular to the central axis J1 of the first casing 21 in the axial direction. A slight gap due to tolerance or the like may exist between the upper end surface of the second upper bearing 252 and the surface of the first casing 21.

  The above-described rotation prevention unit 526 is located on the radially outer side than the second upper bearing 252. Further, the rotation preventing unit 526 overlaps the second upper bearing 252 in the radial direction. In the example shown in FIG. 2, a part of the rotation preventing portion 526 in the axial direction overlaps the second upper bearing 252 in the radial direction. In other words, a part of the rotation preventing unit 526 is located at the same position as the second upper bearing 252 in the axial direction. For example, the upper part of the rotation preventing part 526, that is, the upper part of the pin 527 and the upper part of the hole of the internal gear 5 overlap with the second upper bearing 252 in the radial direction.

  When the transmission 1 is used as a speed reducer, the sun gear 33 rotates around the central axis J1 together with the first rotary shaft member 31 that is a high-speed shaft. In other words, the first rotating assembly 3 rotates around the central axis J1. Due to the rotation of the sun gear 33, each planetary gear 44 engaged with the sun gear 33 rotates about the planetary axis J2. As described above, since each planetary gear 44 is also engaged with the internal gear 5 fixed to the casing 2, the plurality of planetary gears 44 rotates around the central axis J1.

  In the following description, the rotation of each planetary gear 44 around the planet axis J2 is referred to as “spinning”, and the rotation of the plurality of planetary gears 44 around the center axis J1 is referred to as “revolution”. As described above, the planet carrier 42 is connected to the plurality of planet gears 44 via the plurality of planet shaft members 43, and the second rotating shaft member 41, which is a low speed shaft, is connected to the planet carrier 42. For this reason, with the revolution of the plurality of planetary gears 44, the planet carrier 42 and the second rotating shaft member 41 also rotate around the central axis J1. That is, the second rotating assembly 4 rotates around the central axis J1.

  When the transmission 1 is used as a speed increaser, the second rotating shaft member 41, the planet carrier 42 and the plurality of planetary gears 44 of the second rotating assembly 4 are opposite to the case where the transmission 1 is used as a speed reducer. It rotates around the central axis J1. Since each planetary gear 44 is engaged with the internal gear 5 as described above, it rotates around the planetary axis J2. Due to the rotation of each planetary gear 44, the sun gear 33 that engages with each planetary gear 44 rotates about the central axis J <b> 1 together with the first rotation shaft member 31.

  As described above, even when the transmission 1 is used as a speed reducer or a speed increaser, torque is transmitted between the first rotating assembly 3 and the second rotating assembly 4. Done.

  When the transmission 1 is assembled, first, the internal gear 5 is attached to the second casing 22. The internal gear 5 is attached to the second casing 22 by, for example, an intermediate fit as described above. A plurality of planetary gears 44 are attached to the planet carrier 42 by a plurality of planetary shaft members 43. Further, the second rotating shaft member 41 is connected to the planet carrier 42. Thereby, the 2nd rotation assembly 4 is formed.

  Subsequently, the second upper bearing 252 and the second lower bearing 251 are attached to the upper and lower portions of the planet carrier 42. The second upper bearing 252 is attached to the planet carrier 42 by, for example, press-fitting the second upper bearing 252 into the support upper surface portion 425. The second lower bearing 251 is attached to the planet carrier 42 by, for example, press-fitting the second lower bearing 251 into the carrier shaft portion 421.

  Next, the second rotating assembly 4 to which the second upper bearing 252 and the second lower bearing 251 are fixed is inserted and attached into the second casing 22 to which the internal gear 5 is fixed. At this time, the second lower bearing 251 is fixed to the second casing 22 by the outer peripheral surface of the second lower bearing 251 being in contact with the inner peripheral surface of the second casing 22. The second lower bearing 251 is fixed to the second casing 22 by, for example, shrink fitting.

  The second upper bearing 252 is fixed to the internal gear 5 by the outer peripheral surface of the second upper bearing 252 being in contact with the inner peripheral surface of the bearing support portion 52 of the internal gear 5. The second upper bearing 252 is fixed to the internal gear 5 by, for example, an intermediate fit. In other words, in a state where the inner peripheral surface of the internal gear 5 and the outer peripheral surface of the second upper bearing 252 are in contact with each other before the second upper bearing 252 is fixed to the internal gear 5, the second upper bearing The diameter of the outer peripheral surface of 252 is substantially the same as the diameter of the inner peripheral surface of the internal gear 5.

  In parallel with the attachment of the second rotary assembly 4 to the second casing 22, the sun gear 33 is attached to the first rotary shaft member 31 to form the first rotary assembly 3. A first bearing 24 is attached to the first rotating assembly 3. The first bearing 24 is attached to the first rotating assembly 3 by, for example, press-fitting the first bearing 24 into the first rotating shaft member 31.

  Subsequently, the first rotating assembly 3 to which the first bearing 24 is fixed is inserted into the first casing 21 and attached. At this time, the first bearing 24 is fixed to the first casing 21 by the outer peripheral surface of the first bearing 24 being in contact with the inner peripheral surface of the first casing 21. The first bearing 24 is fixed to the first casing 21 by, for example, shrink fitting.

  Thereafter, the first casing 21 is attached to the second casing 22. When the first casing 21 is attached to the second casing 22, the sun gear 33 protruding downward from the first casing 21 is inserted into the planetary support portion 422 from the central opening of the support upper surface portion 425 of the planetary carrier 42. The Further, the first casing 21 is fixed to the second upper bearing 252 by the inner peripheral surface of the lower end portion of the first casing 21 being in contact with the outer peripheral surface of the second upper bearing 252. The first casing 21 is fixed to the second upper bearing 252 by, for example, an intermediate fit. The first casing 21 and the second casing 22 are attached to each other by a fitting structure via the second upper bearing 252. Then, the 1st casing 21 and the 2nd casing 22 are mutually fixed with the volt | bolt 23, and the transmission 1 is formed.

  As described above, the transmission 1 includes the casing 2, the first rotation assembly 3, the second rotation assembly 4, and the annular internal gear 5. The first rotating assembly 3 is supported by the casing 2 so as to be rotatable about the central axis J1. The second rotating assembly 4 is rotatably supported by the casing 2 via the second upper bearing 252 around the central axis J1 and transmits rotational force to and from the first rotating assembly 3. The internal gear 5 is fixed to the casing 2 on the radially outer side of the second rotary assembly 4. The first rotating assembly 3 includes a first rotating shaft member 31 and a sun gear 33. In the first rotating shaft member 31, the central axis J1 is located at the center. The sun gear 33 rotates with the first rotating shaft member 31 in the casing 2.

  The second rotating assembly 4 includes a planet carrier 42, a plurality of planet gears 44, and a second rotating shaft member 41. The plurality of planetary gears 44 are arranged in the circumferential direction on the radially outer side of the sun gear 33 in the casing 2. The plurality of planetary gears 44 are rotatably supported by the planetary carrier 42 around the planetary axis J2 that faces the direction along the central axis J1. The outer peripheral teeth of the plurality of planetary gears 44 engage with the outer peripheral teeth of the sun gear 33 and the inner peripheral teeth of the internal gear 5. In the second rotating shaft member 41, the central axis J1 is located at the center. The second rotating shaft member 41 is connected to the planet carrier 42. The second upper bearing 252 is in contact with the outer peripheral surface of the planet carrier 42 and the inner peripheral surface of the internal gear 5 in the radial direction. Thereby, when the transmission 1 is assembled, the coaxiality between the planet carrier 42 and the internal gear 5 can be easily improved.

  The second upper bearing 252 is in contact with the planet carrier 42 and the internal gear 5 in the axial direction. Thereby, the position in the axial direction of the second upper bearing 252 with respect to the planet carrier 42 and the internal gear 5 can be determined with high accuracy.

  As described above, the casing 2 includes the first casing 21 and the second casing 22. The first casing 21 accommodates and supports the first rotary assembly 3 therein. The second casing 22 faces the first casing 21 in the axial direction. The second casing 22 accommodates the second rotating assembly 4 inside and supports the second rotating assembly 4 via the second upper bearing 252. The casing boundary portion 26 where the axial end surface of the first casing 21 and the axial end surface of the second casing 22 are in contact with the second upper bearing 252 in the radial direction. The axial position of the casing boundary 26 is different from the axial position of the central portion of the second upper bearing 252 in the axial direction. Thereby, it can suppress that the 2nd upper bearing 252 deform | transforms or breaks by the stress which arises in the casing 2. FIG. As a result, the life of the second upper bearing 252 can be extended.

  The casing 2 further includes a bolt 23 that is a connecting member facing in the axial direction. The bolt 23 connects the first casing 21 and the second casing 22. Thereby, the 1st casing 21 and the 2nd casing 22 can be firmly fixed by a low-cost and simple method.

  As described above, the end surface of the planet carrier 42 in the axial direction overlaps the second upper bearing 252 in the radial direction. The axial position of the end surface in the axial direction of the planet carrier 42 is different from the axial position of the central portion of the second upper bearing 252 in the axial direction. Thereby, it is possible to suppress the second upper bearing 252 from being deformed or damaged by the load from the planet carrier 42. As a result, the life of the second upper bearing 252 can be extended.

  As described above, the transmission 1 further includes the rotation prevention unit 526. The rotation preventing portion 526 is a concave portion and a convex portion facing in the axial direction at the contact portion between the internal gear 5 and the casing 2, and engages with each other. The rotation preventing unit 526 is located on the radially outer side than the second upper bearing 252. Thereby, the rotation prevention part 526 can be arrange | positioned in the position away from the central axis J1. As a result, relative rotation of the internal gear 5 with respect to the casing 2 can be prevented.

  Further, the rotation preventing unit 526 overlaps the second upper bearing 252 in the radial direction. Thereby, the casing 2 can be reduced in size in the axial direction. Or the freedom degree of design in the site | part of the rotation prevention part 526 vicinity of the casing 2 can be improved. As described above, the circumferential position of the rotation preventing portion 526 is different from the circumferential position of the bolt 23 that is the connecting member. Thereby, the transmission 1 can be reduced in size in the radial direction.

  The outer peripheral surface of the internal gear 5 includes a cylindrical surface portion 521 and a convex surface portion 522. The cylindrical surface portion 521 is a part of a cylindrical surface centered on the central axis J1. The convex surface portion 522 protrudes outward in the radial direction from the cylindrical surface portion 521. The rotation preventing part 526 is located on the radially inner side of the convex surface part 522. The bolt 23 that is the connecting member described above is located on the radially outer side of the cylindrical surface portion 521. Thereby, the transmission 1 can be reduced in size in the radial direction.

  As described above, the outer peripheral surface of the second upper bearing 252 is in contact with the inner peripheral surface of the internal gear 5. Further, the diameter of the outer peripheral surface of the second upper bearing 252 is the same as the diameter of the inner peripheral surface of the internal gear 5 before the second upper bearing 252 is fixed to the internal gear 5. Accordingly, the internal gear 5 and the second upper bearing 252 are suitably fixed to each other while suppressing the load at the time of fixing the internal gear 5 and the second upper bearing 252 from adversely affecting the second upper bearing 252. Can do.

  Various changes can be made in the transmission 1 described above.

  For example, the axial position of the casing boundary 26 may be the same as the axial position of the central portion of the second upper bearing 252 in the axial direction. Further, the axial position of the end surface in the axial direction of the planet carrier 42 may be the same as the axial position of the central portion of the second upper bearing 252 in the axial direction.

  The first casing 21 and the second casing 22 may be connected by various connection members other than the bolts 23. Moreover, the casing 2 does not necessarily need to be formed by connecting the two members of the first casing 21 and the second casing 22, and may be a single member, for example.

  For example, the rotation preventing unit 526 may be located at substantially the same position as the second upper bearing 252 in the radial direction. In addition, the rotation prevention unit 526 may be positioned at substantially the same position as the connection member described above in the circumferential direction, for example.

  In the transmission 1, the second lower bearing 251 may be omitted. In this case, for example, a cross gear bearing is used as the second upper bearing 252. The second upper bearing 252 does not necessarily overlap the casing boundary portion 26 in the radial direction. For example, the second upper bearing 252 may be in contact with the outer peripheral surface of the planet carrier 42 and the inner peripheral surface of the internal gear 5 in the radial direction below the gear portion 51 and the planetary gear 44 of the internal gear 5.

  In the transmission 1, the shape of each component such as the internal gear 5 and the planet carrier 42 may be variously changed. Attachment of each component of the transmission 1 may be performed by various methods other than those described above. Moreover, attachment of each structure may be performed directly and may be performed via another member.

  The transmission 1 shown in FIG. 1 includes only one planetary gear group, which is a set of a plurality of planetary gears 44 arranged in the circumferential direction at the same position in the axial direction. It may include a plurality of planetary gear groups arranged in a group.

  The configurations in the above-described embodiments and modifications may be combined as appropriate as long as they do not contradict each other.

  The transmission according to the present invention can be used as a speed reducer or speed increaser in various devices such as precision processing machines and 3D measuring devices. The transmission according to the present invention can also be used for other applications.

DESCRIPTION OF SYMBOLS 1 Transmission 2 Casing 3 1st rotation assembly 4 2nd rotation assembly 5 Internal gear 21 1st casing 22 2nd casing 23 Bolt 26 Casing boundary part 31 1st rotating shaft member 33 Sun gear 41 2nd rotating shaft member 42 Planet carrier 44 Planet gear 252 Second upper bearing 521 Cylindrical surface portion 522 Convex surface portion 526 Anti-rotation portion J1 Central axis J2 Planetary axis

Claims (10)

A casing,
A first rotating assembly that is rotatably supported by the casing about a central axis;
A second rotating assembly that is rotatably supported by the casing via a bearing around the central axis, and that transmits rotational force to and from the first rotating assembly;
An annular internal gear fixed to the casing on the radially outer side of the second rotating assembly;
With
The first rotating assembly includes:
A first rotating shaft member having the central axis positioned at the center;
A sun gear that rotates with the first rotating shaft member in the casing;
With
The second rotating assembly includes:
With planetary carriers,
In the casing, it is arranged in the circumferential direction outside the sun gear in the radial direction, and is supported rotatably by the planet carrier about a planetary axis that faces the direction along the central axis, and each outer peripheral tooth is A plurality of planetary gears engaged with the outer peripheral teeth of the sun gear and the inner peripheral teeth of the internal gear;
A second rotating shaft member connected to the planet carrier and centered on the central axis;
With
A transmission in which the bearing is in radial contact with an outer peripheral surface of the planet carrier and an inner peripheral surface of the internal gear.   The transmission according to claim 1, wherein the bearing is in axial contact with the planet carrier and the internal gear. The casing is
A first casing that accommodates and supports the first rotating assembly;
A second casing that faces the first casing in the axial direction, accommodates the second rotating assembly inside, and supports the bearing through the bearing;
With
A casing boundary portion where the axial end surface of the first casing and the axial end surface of the second casing are in contact with each other in the radial direction overlaps the bearing, and the axial position of the casing boundary portion is the axial center of the bearing. The transmission according to claim 1, wherein the transmission is different from an axial position of the portion. The casing is
A first casing that accommodates and supports the first rotating assembly;
A second casing that faces the first casing in the axial direction, accommodates the second rotating assembly inside, and supports the bearing through the bearing;
A connecting member facing in the axial direction connecting the first casing and the second casing;
The transmission according to claim 1, comprising:   The axial end surface of the planet carrier overlaps with the bearing in the radial direction, and the axial position of the axial end surface of the planet carrier is different from the axial position of the axial central portion of the bearing. The transmission in any one of thru | or 4. A concave portion and a convex portion facing in the axial direction at the contact portion between the internal gear and the casing, further comprising a rotation preventing portion that engages with each other;
The transmission according to any one of claims 1 to 5, wherein the rotation preventing portion is located radially outside the bearing.   The transmission according to claim 6, wherein the rotation preventing portion overlaps the bearing in a radial direction. A concave portion and a convex portion facing in the axial direction at the contact portion between the internal gear and the casing, further comprising a rotation preventing portion that engages with each other;
The casing is
A first casing that accommodates and supports the first rotating assembly;
A second casing that faces the first casing in the axial direction, accommodates the second rotating assembly inside, and supports the bearing through the bearing;
A connecting member facing in the axial direction connecting the first casing and the second casing;
With
The transmission according to claim 1 or 2, wherein a circumferential position of the rotation preventing portion is different from a circumferential position of the connection member. The outer peripheral surface of the internal gear is
A cylindrical surface portion that is a part of the cylindrical surface centered on the central axis;
A convex surface portion projecting radially outward from the cylindrical surface portion;
With
The anti-rotation portion is located radially inside the convex surface portion;
The transmission according to claim 8, wherein the connection member is located on a radially outer side of the cylindrical surface portion. An outer peripheral surface of the bearing is in contact with the inner peripheral surface of the internal gear;
The diameter of the said outer peripheral surface of the said bearing is the same as the diameter of the said inner peripheral surface of the said internal gear in the state before the said bearing is fixed to the said internal gear. Gearbox.

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