JP2017201192A - Deceleration device and optical equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a deceleration device having a wide width of a usable temperature.SOLUTION: A deceleration device 1 includes: a first rotating body 10 rotating about a first axis A1; a plurality of second rotating bodies 20 each disposed around the first rotating body 10, revolving about the first axis A1 through rotation of the first rotating body 10 and rotating about a second axis A2 that is an axis of each of the second rotating bodies; a third rotating body 30 having holding sections 31A, 31B with insertion holes 301, 311 into which rotating sections 23A, 23B each rotating along the second axis A2 in the second rotating bodies 20 are inserted, and rotating about the first axis A1 through the revolution of the second rotating bodies 20; and cylindrical members 304, 314 disposed between inner peripheries of the insertion holes 301, 311 and outer peripheries of the rotating sections 23 and each having a linear expansion coefficient different from those of the holding sections 31A, 31B and the rotating sections 23.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a reduction gear and an optical apparatus.

  Conventionally, in a traction drive type speed reducer that transmits a rotational force by a frictional force, for example, Patent Document 1 proposes a configuration for preventing a decrease in transmission efficiency of a rotational force due to a slip during rotation of a planetary roller.

JP 2000-35097 A

The speed reducer according to the present invention is arranged around a first rotating body that rotates around a first axis, and revolves around the first axis by the rotation of the first rotating body. In addition, there are provided a plurality of second rotating bodies that rotate about the second axis that is each axis, and an insertion hole into which the rotating part that rotates along the second axis of the second rotating body is inserted. A holding portion that is disposed between a third rotating body that rotates about the first axis by the revolution of the second rotating body, and an inner periphery of the insertion hole and an outer periphery of the rotating portion; And a cylindrical member having a linear expansion coefficient different from that of the rotating part.
An optical apparatus of the present invention includes an actuator that generates a driving force and a driving unit that transmits the driving force to a lens and drives the lens, and the reduction device described above is interposed between the driving unit and the actuator. It was set as the structure provided.

It is a schematic sectional drawing of the speed reducer of 1st Embodiment. It is an enlarged view of area | region S1 of FIG. It is an enlarged view of area | region S2 of FIG. It is the schematic of BB sectional drawing of FIG. It is CC sectional drawing of FIG. It is AA sectional drawing of FIG. It is a schematic sectional drawing of the speed reducer of 2nd Embodiment. It is a figure explaining the camera using the reduction gear of this embodiment.

Hereinafter, embodiments will be described with reference to the drawings and the like.
FIG. 1 is a schematic cross-sectional view of a speed reducer 1 according to an embodiment. FIG. 2 is an enlarged view of the region S1 in FIG. FIG. 3 is an enlarged view of the region S2 in FIG.

As illustrated, the speed reduction device 1 includes a sun roller 10, a plurality of planetary rollers 20 disposed around the sun roller 10, and an output shaft 30 connected to the planetary roller 20.
Further, the speed reduction device 1 is a bottomed cylindrical shape that covers the outer periphery of the sun roller 10 and the planetary roller 20, and includes an outer shell portion 40 provided with an output shaft insertion hole 41 through which the output shaft 30 is inserted, and an outer shell portion. And a lid 50 provided with a sun roller insertion hole 58 through which the sun roller 10 is inserted.
In this specification, the lid 50 side in FIG. 1 will be described as the upper side, and the bottom 44 side of the outer shell 40 will be described as the lower side.

The sun roller 10 is a cylindrical member that can rotate around an axis (sun axis A1), and an upper end is connected to an output shaft of an actuator (not shown) and is driven to rotate by rotation of the output shaft of the actuator.
The sun roller 10 is inserted through the sun roller insertion hole 58 of the lid 50 as described above.
The sun roller 10 is supported by a first bearing 54 attached to the outer periphery of the sun roller insertion hole 58 in the upper part of the lid 50 so as to be rotatable about the sun axis A1 and immovable in the radial direction.

The sun roller 10 has a flange 11, and a rotating roll 52 is sandwiched between the upper surface of the flange 11 and the lower surface of the lid 50.
The collar portion 11 of the sun roller 10 is pressurized in the thrust direction with the rotary roll 52 sandwiched by a spring force of the lid portion 50 described later, and can be rotated by the rotary roll 52.
In addition, the structure which can rotate the sun roller 10 with respect to the cover part 50, and pressurizes it in a thrust direction is not limited to the rotating roll 52 of embodiment, For example, a sliding system may be sufficient.

The sun roller 10 has a large-diameter portion 10a including a portion to which the flange portion 11 is attached, and a small-diameter portion 10b having a smaller diameter than the large-diameter portion 10a provided in the lower portion.
Between the large-diameter portion 10a and the small-diameter portion 10b, an inclined surface (taper) whose diameter gradually changes is provided. In the cross section shown in FIGS. 1 and 2, the slope is a straight line inclined at a predetermined angle with respect to the sun axis A <b> 1 and serves as a solar side contact portion 12 that contacts the planetary roller 20.

Three planetary rollers 20 are arranged on the outer periphery of the lower portion of the sun roller 10 with an interval of 120 ° from each other. However, the number of planetary rollers 20 and the angle of arrangement are not limited thereto. Since FIG. 1 is a cross-sectional view in the DD direction of FIG. 6 described later, two planetary rollers 20 are illustrated. However, in the radial cross-sectional view, the number of planetary rollers 20 is one.
As shown in FIG. 1, the planetary roller 20 includes a T-shaped portion 24 having a T-shaped cross section, a planetary rotation shaft upper portion 23 </ b> A projecting upward along the central axis of the T-shaped portion 24, and projecting downward. The planetary rotating shaft lower portion 23B is integrated.
The T-shaped portion 24 of the planetary roller 20 includes a large ring portion 21 and a small ring portion 22 provided at a lower portion of the large ring portion 21.

  As shown in FIG. 2, the outer periphery of the large ring portion 21 of the planetary roller 20 is a planetary first contact portion 21a, and the cross section is formed in a curved shape such as a perfect circle or an elliptical arc. However, the shape is not limited to a perfect circle or an elliptical arc shape, and may be a rounded shape having no corners.

  As shown in FIG. 3, the lower end of the outer periphery of the small ring portion 22 of the planetary roller 20 is a planetary second contact portion 22a. Like the planetary first contact portion 21a, the cross section is a perfect circle, an elliptical arc shape, or the like. It is formed in the shape of a curve. However, similarly to the planetary side first contact portion 21a, the shape is not limited to a perfect circle or an elliptical arc shape, and may be any round shape having no corners.

  As described above, the outer shell portion 40 has a bottomed cylindrical shape that covers the outer periphery of the sun roller 10 and the planetary roller 20, and includes the cylindrical portion 43 and the bottom portion 44 provided at the lower end of the cylindrical portion 43.

  As described above, the circular output shaft insertion hole 41 through which the output shaft 30 passes is provided at the center of the bottom portion 44. A second bearing 47 is disposed around the output shaft insertion hole 41 on the outer surface of the bottom portion 44.

  The cylindrical portion 43 is thin so that the inner diameter is enlarged within a predetermined length from the upper end, and a step 45 is provided on the inner diameter side.

An annular member 60 is attached by screws 62 at the corners of the bottom 44 and the cylindrical portion 43 inside the outer shell 40.
In the cross section shown in FIG. 1, the annular member 60 has a pentagonal shape in which rectangular corners are obliquely cut, and the outer periphery is in contact with the inner periphery of the cylindrical portion 43 of the outer shell portion 40. .
The upper corner on the inner diameter side of the annular member 60 is a slope (taper) so as to be a straight line inclined at a predetermined angle with respect to the sun axis A1 in the cross section shown in FIG. 1 and FIG. The outer shell side contact portion 61 is in contact with the portion 22a.

  The lid portion 50 includes a cylindrical portion 43 of the outer shell portion 40, a lid cylindrical portion 51 having the same inner diameter and outer diameter, and an upper plate portion 53 that covers the upper end of the lid cylindrical portion 51.

  A stepped portion 55 having a predetermined length is formed on the inner diameter side of the lower end of the lid portion cylindrical portion 51. The step portion 55 engages with the step portion 45 described above.

The upper plate portion 53 is made of a spring member. Further, as described above, the first bearing 54 is disposed around the sun roller insertion hole 58.
A hole 57 for inserting a screw 56 is provided in the vicinity of the edge of the lid 50. When the lid 50 is attached to the outer shell 40, the lid 50 is engaged by engaging the step portions 45 and 55. And a screw 56 is inserted into the hole 57.
A screw hole 46 is provided in an upper portion of the outer shell portion 40, and the lid portion 50 is fixed to the outer shell portion 40 by screwing a screw 56 into the screw hole 46.
In the present embodiment, the upper plate portion 53 is manufactured by a spring member and applied with pressure when the speed reducer 1 is assembled. However, the structure for generating the pressure is not limited to this, and the planetary roller 20, You may implement | achieve by installing the coil spring for thrust pressurization in the planetary roller holding | maintenance part 31 or the sun roller 10. FIG.
It is preferable that any of the applied pressures has a structure that works by fastening the lid 50.

The output shaft 30 is a rotating member centered on the output axis A3. The planetary roller holding portion 31 disposed inside the outer shell portion 40, and the output shaft insertion hole 41 from the center lower surface of the planetary roller holding portion 31. And an output part 32 extending downward.
The output unit 32 is coupled to a transmission mechanism that transmits a rotational driving force from an actuator (not shown) coupled to the sun roller 10. The transmission mechanism transmits the rotational driving force as a straight driving force, and is used, for example, to drive the lens group linearly.

  As shown in FIG. 1, the planetary roller holding unit 31 includes an upper planetary roller holding unit 31A and a lower planetary roller holding unit 31B.

  4 is a cross-sectional view taken along the line BB of FIG. The upper planetary roller holding portion 31A is a disk member, and includes three planetary rotation shaft upper insertion holes 301 through which the planetary rotation shaft upper portion 23A is inserted, one solar roller insertion hole 302 through which the sun roller 10 is inserted, There are provided three connected cylindrical upper insertion holes 303 through which the upper ends of the connected cylindrical members 305 that connect the upper planetary roller holding part 31A and the lower planetary roller holding part 31B are inserted.

Three planetary rotation shaft upper insertion holes 301 are equally provided around the axis A1 at intervals of 120 °. Three connecting cylinder upper insertion holes 303 are equally provided between the planetary rotation shaft upper insertion holes 301 at intervals of 120 ° around the axis A1. The sun roller insertion hole 302 is provided at the center of the disk member.
Four or more planetary rollers 20 and connecting cylindrical members 305 may be provided. For example, when n planetary rollers 20 or connecting cylindrical members 305 are provided, the arrangement interval around the axis A1 can be evenly arranged at an angle of (360 ° / n). The same applies to the planetary rotating shaft upper insertion hole 301 and the connecting cylinder upper insertion hole 303 provided correspondingly.

  A gap is provided between the inner surface of the sun roller insertion hole 302 and the sun roller 10, and the sun roller 10 and the upper planetary roller holding portion 31A are not in contact with each other.

A first cylindrical member 304 (bush liner) is disposed between the inner surface of the planetary rotating shaft upper portion insertion hole 301 and the outer surface of the planetary rotating shaft upper portion 23A.
Here, the first cylindrical member 304 is a sliding bearing, and the friction coefficient between the inner surface of the first cylindrical member 304 and the outer surface of the planetary rotating shaft upper portion 23A is small. Therefore, the planetary roller 20 is restricted from moving in the radial direction by the first cylindrical member 304, but the internal rotation of the first cylindrical member 304 is performed smoothly.
Further, the diameter increases from the portion of the planetary rotation shaft upper portion 23A inserted through the planetary rotation shaft upper insertion hole 301 downward, so that the first cylindrical member 304 does not fall downward.

Further, the coefficient of friction between the outer surface of the first cylindrical member 304 and the inner surface of the planetary rotating shaft upper insertion hole 301 of the upper planetary roller holding portion 31A may be reduced.
In this case, the radial movement of the planetary roller 20 in a state where the first cylindrical member 304 is extrapolated is limited by the inner surface of the planetary rotation shaft upper insertion hole 301, but inside the planetary rotation shaft upper insertion hole 301. The rotation of the planetary roller 20 in a state where the first cylindrical member 304 is extrapolated is smoothly performed.

5 is a cross-sectional view taken along the line CC of FIG. The lower planetary roller holding portion 31B is a disk member, and connects the three planetary rotary shaft lower insertion holes 311 through which the planetary rotary shaft lower portion 23B is inserted, and the upper planetary roller holding portion 31A and the lower planetary roller holding portion 31B. There are provided three connecting column lower insertion holes 313 through which the lower ends of the connecting column members 305 to be inserted are inserted.
The three planetary rotation shaft lower insertion holes 311 are equally provided around the output axis A3 at intervals of 120 °. Three connecting column lower insertion holes 313 are equally provided between the planetary rotation shaft lower insertion holes 311 around the axis A1 at intervals of 120 °.
A second cylindrical member 314 (bush liner) is disposed between the inner surface of the planetary rotating shaft lower portion insertion hole 311 and the outer surface of the planetary rotating shaft lower portion 23B.
Here, the second cylindrical member 314 is a sliding bearing, and the coefficient of friction between the inner surface of the second cylindrical member 314 and the outer surface of the planetary rotating shaft lower portion 23B is small. Therefore, the planetary roller 20 is restricted from moving in the radial direction by the second cylindrical member 314, but the internal rotation of the second cylindrical member 314 is smoothly performed.
The second cylindrical member 314 does not fall downward from the planetary rotating shaft lower insertion hole 311 of the lower planetary roller holding portion 31B, for example, by providing a protrusion for holding the lower portion of the second cylindrical member 314 on the lower planetary rotating shaft portion 23B. It is preferable that such a mechanism is provided.

  Further, in the present embodiment, the upper planetary roller holding portion 31A and the lower planetary roller holding portion 31B are made of a member having a large thermal expansion coefficient, for example, a resin. On the other hand, the second cylindrical member 314 and the planetary roller 20 are made of a member having a small coefficient of thermal expansion, such as a metal. The second cylindrical member 314 and the planetary roller 20 are preferably made of a material having an equivalent thermal expansion coefficient.

  An output part 32 extends downward in the lower part of the central part of the lower planetary roller holding part 31B. The output part 32 is inserted through the output shaft insertion hole 41, is supported by the second bearing 47 so as to be rotatable and immovable in the radial direction, and is attached to a driven part (not shown).

  In addition, it is preferable to cover the surface of the static friction drive transmission portion of each roller with traction oil or grease.

Here, as described above, the sun-side contact portion 12 has a linear shape inclined at a predetermined angle with respect to the solar axis A1 as shown in FIG.
And in the contact part (planet side 1st contact part 21a) which the planetary roller 20 contacts with the solar roller 10, since the tangent L1 which contact | connects the contact part follows the sun side contact part 12, the tangent L1 is solar axis A1. Will lean against.
The curvature of the planetary first contact portion 21a of the large ring portion 21 of the planetary roller 20 is preferably smaller than r12 (illustrated in FIG. 1) corresponding to the deflection radius by the spring portion. As a result, due to the deflection that occurs in the portion corresponding to r12, it is easy to suppress the drift of the reduction ratio and the fluctuation in the cycle that occur when the positions of the planetary first contact portion 21a and the sun side contact portion 12 are shifted.
Furthermore, it is preferable that the direction of the tangent line in contact with the planet-side first contact portion 21 a of the large ring portion 21 of the planetary roller 20 is parallel to the sun-side contact portion 12 of the counterpart sun roller 10.

Further, the upper corner on the inner diameter side of the annular member 60 is a straight line inclined at a predetermined angle with respect to the sun axis A1 in the cross section shown in FIGS.
And in the contact part (planet side 2nd contact part 22a) with respect to the annular member 60 of the planetary roller 20, since the tangent L2 which contact | connects the contact part follows the outer shell side negotiation part 61, it inclines with respect to the solar axis A1. ing.
Further, the curvature of the planetary roller side second contact portion 22a of the small ring portion 22 of the planetary roller 20 of the roller portion corresponding to the inner teeth of the planetary roller 20 is smaller than r24 (illustrated in FIG. 1) corresponding to the deflection radius by the spring portion. Is preferred. As a result, due to the deflection occurring in the portion corresponding to r24, it becomes easier to suppress the drift of the reduction ratio and the fluctuation within the cycle caused by the positions of the planetary second contact portion 22a and the small ring portion 22 being shifted.
Further, it is preferable that the direction of the tangent line in contact with the planetary second contact portion 22 a of the small ring portion 22 of the planetary roller 20 is parallel to the outer shell side contact portion 61 of the counterpart annular member 60.

The design formulas for the diameters and reduction ratios of the sun roller 10 and the planetary roller 20 of the reduction gear 1 are the same as those of the reduction gear mechanism of the planetary roller 20 with the internal tooth equivalent roller portion (sun roller) as a mechanical ground. Based on the principle of static friction transmission between rollers (the transmission circumferential length of the rollers in contact with each other becomes equal), the following is obtained as shown in FIG.
r1: distance from the solar axis A1 of the solar side contact portion 12 of the sun roller 10 r2: distance from the planetary axis A2 of the planetary first contact portion 21a of the planetary roller 20 r2 ′: planetary second contact of the planetary roller 20 The distance from the planet axis A2 of the portion 22a r4: The distance from the sun axis A1 of the outer shell side contact portion 61 of the planetary roller 20 θ1: The rotation angle of the sun roller 10 about the sun axis A1 θ2: The planetary roller 20 Rotational rotation angle about the planetary axis A2 θ4: Revolutional rotation angle about the solar axis A1 of the planetary roller 20

For example, as deceleration example 1,
When r1 = 0.2 mm, r2 = 0.8 mm, r2 ′ = 0.2 mm, r4 = 1.2 mm, reduction ratio: θ4 / θ1 = 0.2 / 0.8 * 0.2 / 1.2 = 1/24.

For example, as deceleration example 2,
When r1 = 0.4 mm, r2 = 1.2 mm, r2 ′ = 0.2 mm, r4 = 1.8 mm, the reduction ratio: θ4 / θ1 = 0.4 / 1.2 * 0.2 / 1.8 = 1/3 * 1/9 = 1/27.

For example, as deceleration example 3,
When r1 = 0.6 mm, r2 = 1.8 mm, r2 ′ = 0.4 mm, r4 = 2.8 mm, the reduction ratio: θ4 / θ1 = 0.6 / 1.8 * 0.4 / 2.8 = 1/3 * 1/7 = 1/21.

For example, as deceleration example 4,
When r1 = 0.4 mm, r2 = 1.6 mm, r2 ′ = 0.4 mm, r4 = 2.4 mm, the reduction ratio is θ4 / θ1 = 1/24.

Next, an assembling method of the reduction gear 1 will be described.
(1) First, the planetary rotating shaft lower portion 23B of the planetary roller 20 is inserted into the planetary rotating shaft lower portion insertion hole 311 provided in the lower planetary roller holding portion 31B. At this time, the second cylindrical member 314 is disposed between the inner surface of the planetary rotating shaft lower portion insertion hole 311 and the outer surface of the planetary rotating shaft lower portion 23B.

  Since the planetary rotation shaft lower insertion holes 311 are equally provided around the output axis A3 at intervals of 120 °, the planetary rollers 20 are evenly arranged around the output axis A3 at intervals of 120 °. The Then, the connecting column member 305 is inserted into the connecting column lower insertion hole 313.

Next, the upper planetary roller holding portion 31 </ b> A is disposed from above the planetary roller 20. At this time, the upper ends of the planetary rotating shaft upper part 23A and the connecting cylindrical member 305 are inserted into the planetary rotating shaft upper insertion hole 301 and the connecting cylinder upper inserting hole 303.
Here, the first cylindrical member 304 is disposed between the inner surface of the planetary rotation shaft upper portion insertion hole 301 and the outer surface of the planetary rotation shaft upper portion 23A.

  Thereby, the planetary rotating shaft upper portion 23A of the planetary roller 20 is held in a state where the cylindrical member 304 is interposed in the planetary rotating shaft upper insertion hole 301 of the upper planetary roller holding portion 31A, and the planetary roller 20 has a lower planetary rotating shaft lower portion. 23B is held in a state where the cylindrical member 314 is interposed in the planetary rotating shaft lower insertion hole 311 of the lower planetary roller holding portion 31B.

(2) The output shaft 30 holding the planetary roller 20 is inserted into the outer shell portion 40 to which the lid portion 50 is not attached, and the end of the output shaft 30 is inserted into the output shaft provided on the bottom portion 44. Take it out from the hole 41.
Then, the planetary second contact portion 22 a of the planetary roller 20 comes into contact with the outer shell side contact portion 61 of the annular member 60.
The output shaft 30 is rotatably supported by the bottom portion 44 of the outer shell portion 40 by the second bearing 47, and the output axis A <b> 3 of the output shaft 30 is disposed at the center of the outer shell portion 40.
At this time, the outer shell side contact portion 61 is a linear slope inclined at a predetermined angle with respect to the solar axis A1, and the planetary second contact portion 22a has a circular cross section, a circular shape, or the like having a circular cross section. Since it is formed in a curved shape, the outer shell side contact portion 61 and the planetary side second contact portion 22a do not make surface contact but make point contact.

(3) From the inside of the lid part 50, the large diameter part 10a side of the sun roller 10 is inserted, and the end part on the large diameter part 10a side is taken out from the sun roller insertion hole 58 of the lid part 50.
The sun roller 10 is rotatably held on the lid 50 by the first bearing 54. Further, the flange portion 11 and the lid portion 50 of the sun roller 10 are disposed to face each other with the rotary roll 52 interposed therebetween.

(4) In this state, the lid 50 is disposed on the outer shell 40. The step portion 55 of the lid portion 50 engages with the step portion 45 of the cylindrical portion 43 of the outer shell portion 40, the lid portion 50 is positioned with respect to the outer shell portion 40, and the sun roller 10 is positioned with respect to the outer shell portion 40. Centered. Thereby, output axis A3 and solar axis A1 correspond.
In the present embodiment, the step portions 45 and 55 are provided on the inner side of the outer shell portion 40 and the lid portion 50. However, the present invention is not limited to this, and for example, an end portion may be provided on the outer side.

  When the lid portion 50 is fixed to the outer shell portion 40 with a screw 56, the flange portion 11 is pressed with the ball sandwiched by the spring force of the upper plate portion 53.

And the sun side contact part 12 contacts with the planetary side 1st contact part 21a.
At this time, the solar side contact portion 12 is a linear slope inclined at a predetermined angle with respect to the solar axis A1, and the planetary side first contact portion 21a is a curved line such as an arc having a perfect circle or an ellipse. Therefore, the sun-side contact portion 12 and the planetary-side first contact portion 21a do not make surface contact but make point contact.

  Since the flange portion 11 of the solar roller 10 is pressed downward by the spring force of the plate portion 53, the sun-side contact portion 12 pressurizes the planet-side first contact portion 21a and the planet-side second contact portion 22a. Pressurizes the outer shell side contact portion 61. That is, the planetary roller 20 is held in a state where pressure is applied between the sun roller 10 and the annular member 60.

(Operation)
When the sun roller 10 is rotated by a driving device (not shown), this rotational force is transmitted to the planetary roller 20.
The planetary roller 20 revolves around the sun axis A1 of the sun roller 10 while rotating around the planetary axis A2 of the sun roller 10 to the upper planetary roller holding part 31A and the lower planetary roller holding part 31B.
At this time, the planetary roller 20 revolves together with the upper planetary roller holding portion 31A and the lower planetary roller holding portion 31B while rotating in the planetary rotary shaft upper insertion hole 301 and the planetary rotation shaft lower insertion hole 311.

  Here, the friction coefficient between the inner surface of the first cylindrical member 304 and the outer surface of the planetary rotating shaft upper portion 23A is small. Further, the friction coefficient between the inner surface of the second cylindrical member 314 and the outer surface of the planetary rotating shaft lower portion 23B is small. Therefore, the planetary roller 20 can rotate smoothly with respect to the upper planetary roller holding portion 31A and the lower planetary roller holding portion 31B.

  The upper planetary roller holding portion 31A and the lower planetary roller holding portion 31B are fixed by a connecting cylindrical member 305. For this reason, the upper planetary roller holding portion 31A and the lower planetary roller holding portion 31B are integrated, rotate at a predetermined reduction ratio by rotation around the sun axis A1 of the planetary roller 20, and are integrated with the lower plate. The output shaft 30 also rotates at a predetermined reduction ratio.

(effect)
(1) According to this embodiment, for example, at a low temperature, the resinous upper planetary roller holding portion 31A and the lower planetary roller holding portion 31B contract. Then, the diameters of the planetary rotation shaft upper insertion hole 301 and the planetary rotation shaft lower insertion hole 311 of the upper planetary roller holding portion 31A and the lower planetary roller holding portion 31B are reduced.

  According to the present embodiment, the first cylindrical member 304 and the second cylindrical member 314 are arranged inside the planetary rotation shaft upper insertion hole 301 and the planetary rotation shaft lower insertion hole 311. When the diameters of the planetary rotation shaft upper insertion hole 301 and the planetary rotation shaft lower insertion hole 311 are reduced, the first cylindrical member 304 and the second cylindrical member 314 are tightened from the outer peripheral side.

  However, the first cylindrical member 304 and the second cylindrical member 314 are made of metal and have a small linear expansion coefficient. In the first cylindrical member 304 and the second cylindrical member 314, the contraction force in the radial direction is converted into a compressive force in the circumferential direction, and the contraction in the radial direction of the inner diameter of the first cylindrical member 304 and the second cylindrical member 314 is avoided. can do.

  Therefore, the first cylindrical member 304 and the second cylindrical member 314 do not tighten the planetary rotating shaft upper part 23A and the planetary rotating shaft lower part 23B, and even at a low temperature, the upper planetary roller holding part 31A and the lower planetary roller holding part The rotation of the planetary roller 20 relative to 31B is not hindered.

  On the other hand, as a comparative form, for example, the first cylindrical member 304 and the second cylinder are inserted into the planetary rotation shaft upper insertion hole 301 and the planetary rotation shaft lower insertion hole 311 of the upper planetary roller holding portion 31A and the lower planetary roller holding portion 31B. A case where the member 314 is not disposed will be described. In the case of this comparative form, when the temperature becomes low and the diameters of the planetary rotation shaft upper insertion hole 301 and the planetary rotation shaft lower insertion hole 311 are reduced, the planetary rotation shaft upper portion 23A and the planetary rotation shaft lower portion 23B are directly tightened. When the planetary rotating shaft upper part 23A and the planetary rotating shaft lower part 23B are tightened, the planetary roller 20 cannot rotate.

  However, according to the present embodiment, the first cylindrical member 304 and the second cylindrical member 314 do not fasten the planetary rotating shaft upper portion 23A and the planetary rotating shaft lower portion 23B, and even at a low temperature, the upper planetary roller holding portion 31A. And the rotation of the planetary roller 20 with respect to the lower planetary roller holding part 31B is not hindered.

In the above-described embodiment, the case where the first cylindrical member 304, the second cylindrical member 314, and the planetary roller 20 are metal and the planetary roller holding portions 31A and 31B are resin has been described. However, the present invention is not limited to this, and the materials other than the planetary roller 20 may be made of opposite materials, that is, the first cylindrical member 304 and the second cylindrical member 314 may be made of resin, and the planetary roller holding portions 31A and 31B may be made of metal.
For example, when assembling, the planetary rotating shaft lower portion 23B of the planetary roller 20 is inserted into the planetary rotating shaft lower insertion hole 311 of the lower planetary roller holding portion 31B, and the lower planetary roller holding portion 31B is attached to the planetary rotating shaft lower portion 23B. In the case where all are metal members, etc., if the fitting accuracy is severe, there is a possibility that they cannot be assembled due to contact frictional force or member interference.
However, when the first cylindrical member 304 and the second cylindrical member 314 are thin resin members, the resin has a smaller elastic modulus than that of the metal, and therefore can be assembled even when the fitting accuracy is severe. That is, even when the fitting accuracy is severe, the assembly failure can be reduced by reducing the contact friction force and component interference by elastic deformation of the thin resin member.

(2) According to this embodiment, the sun roller 10 is pressed downward by the spring force of the upper plate portion 53 of the lid portion 50. Thereby, the sun side contact part 12 of the sun roller 10 pressurizes the planetary side 1st contact part 21a below. At this time, the tangent at the contact point between the sun side contact portion 12 and the planetary side first contact portion 21a is oblique with respect to the sun axis A1.
Accordingly, the downward pressing force generates a component force that pushes the planetary roller 20 in a direction perpendicular to the sun axis A1 and the planet axis A2.
Thereby, when the sun roller 10 rotates, the planetary roller 20 can be rotated by a frictional force.
Since the pressing force for rotating the planetary roller 20 can be adjusted by adjusting the vertical pressing force, the configuration for applying the pressing force for rotating the planetary roller 20 can be made compact. .

(3) Since a planetary mechanism is used, it is possible to obtain a high reduction ratio with a compact structure that is coaxial with or parallel to the motor as compared with a conventional gear module.

(4) Since a high reduction ratio can be obtained, the drive transmission direction can be limited only to the actual deceleration direction. Therefore, when applied to an AF motor module, it becomes possible to give a holding force at rest.

(5) Since a high reduction ratio can be obtained, the drive transmission direction can be limited only to the actual deceleration direction. As a result, it is an alternative to the lead screw method that provides one-way output, and can be significantly more compact in the lead direction than the lead screw method.

(6) Since the drive transmission surface can be made of a metal material or a metal oxide material (ceramics), the transmission efficiency is much higher than that of the rubber roller type, and the durability is also high.

(7) According to the present embodiment, since the gear is not used, there is no backlash. Therefore, there is no impact during reciprocating drive.

(8) Unlike the gear structure, there is almost no noise because of the static friction transmission drive.

(9) According to this embodiment, point contact is between the solar side contact portion 12 and the planetary side first contact portion 21a, and between the planetary side second contact portion 22a and the outer shell side contact portion 61.
In the case of surface contact, since the pressure becomes small, there is a possibility that the rotational force is not transmitted well due to slipping etc., but according to this embodiment, since it is a point contact, the applied pressure is concentrated and the surface pressure becomes large. Easy to transmit power.

(10) In the case of surface contact, in the case of point contact, it is easy to apply force evenly between the three planetary rollers.

(11) Further, since the contact is not a surface contact but a point contact, the contact area between the contact portions is reduced, so that the contact portions are prevented from adhering.

(12) Since the planetary rollers 20 around the sun roller 10 are arranged at three positions of 120 °, the sun roller 10 is stable and the sun roller 10 can be centered.

(13) Since the planetary roller 20 bears a thrust burden at the planetary first contact portion 21a, a thrust bearing may not be disposed on the planetary roller 20.

(Second Embodiment)
FIG. 7 is a diagram illustrating a reduction gear device 100 according to the second embodiment. The speed reduction device 100 is different from the speed reduction device 1 in that a coil spring 102 is disposed on the sun roller 101. Since other configurations are the same as those of the reduction gear 1 of the first embodiment, description thereof is omitted.

  The speed reducer 100 is separated into an upper part 101a and a lower part 101b under the flange part 11 of the large diameter part 10a. The upper part 101 a includes an extension part 103 that extends below the flange part 11. The lower part 101b includes an insertion hole 104 into which the extending part 103 can be inserted. A coil spring 102 is attached to the outer periphery of the extension portion 103, and the extension portion 103 is held in the insertion hole 104 in this state.

  According to the present embodiment, only by attaching the lid 50, the spring force of the coil spring 102 allows the planetary side second contact part 22a and the outer shell side to be located between the sun side contact part 12 and the planetary side first contact part 21a. A pressing force can be applied between the contact portion 61 and the contact portion 61. Therefore, the configuration for applying the pressurizing force becomes compact and the pressurizing force adjustment becomes simple.

  Also in this embodiment, the effects (1) to (13) described in the first embodiment can be obtained as in the first embodiment.

Note that the embodiment and the modification can be used in appropriate combination, but detailed description thereof is omitted.
For example, in this embodiment, although the structure using the sun roller 10 and the planetary roller 20 was demonstrated, the structure using not only this but a sun gear and a planetary gear may be sufficient.

FIG. 8 is a diagram illustrating a camera 201 using the speed reduction device 1 of the present embodiment.
The camera 201 includes a camera body 203 having an image sensor 202 and a lens barrel 204 having a lens group.

The lens barrel 204 is an interchangeable lens that can be attached to and detached from the camera body 203, but may be a lens barrel that is integral with the camera body 203. The lens barrel 204 includes a lens holding frame 205, a cam barrel 206, a gear 207, the speed reduction device 1, a motor 208, and the like.
The motor 208 uses an actuator such as an ultrasonic motor or a stepping motor, and is used as a drive source for driving the lens holding frame 205 during the focus adjustment operation of the camera 201. The rotating shaft of the motor 208 is connected to the sun roller 10 of the reduction gear 1, and a gear 207 is attached to the output shaft 30 of the reduction gear 1. The gear 207 meshes with an external gear provided on the outer periphery of the cam cylinder 206.

The lens holding frame 205 holds the lens group 205a, and a cam follower 205b is provided on the outer periphery. The cam follower 205b is engaged with a cam groove 206a provided in the cam cylinder 206, and the lens holding frame 205 is held by the cam cylinder 206 and rotated in the optical axis direction (shown in FIG. 8). It can move in the direction of arrow O).
With the configuration described above, the rotational driving force obtained from the motor 208 is transmitted to the cam barrel 206 via the reduction gear 1 and the gear 207, and the lens holding frame 205 is moved in the direction of the arrow O as the cam barrel 206 rotates. Move to. In this way, the lens group 205a also moves in the direction of the arrow O, and the focus adjustment operation is performed.

  In FIG. 8, a subject image is formed on the imaging surface of the imaging element 202 provided in the camera body 203 by the lens group 205 a provided in the lens barrel 204. The imaged subject image is converted into an electrical signal by the image sensor 202, and image data is obtained by A / D converting the signal.

  A1: Sun axis, A2: Planetary axis, A3: Output axis, 1: Reduction gear, 10: Sun roller, 20: Planetary roller, 23A: Planetary rotating shaft upper part, 23B: Planetary rotating shaft lower part, 30: Output shaft, 31 : Planetary roller holding part, 31A: upper planetary roller holding part, 31B: lower planetary roller holding part, 32: output shaft, 33: shaft holding hole, 34A: upper planetary roller holding part, 34B: lower planetary roller holding part, 201 : Camera, 202: Image sensor, 203: Camera body, 204: Lens barrel, 301: Planetary rotating shaft upper insertion hole, 302: Sun roller insertion hole, 303: Connecting cylinder upper insertion hole, 304: First cylindrical member, 305: Connection column member, 311: Planetary rotating shaft lower insertion hole, 313: Connection column lower insertion hole, 314: Cylindrical member, 314: Second cylinder member

Claims (5)

A first rotating body that rotates about a first axis;
A plurality of second rotating bodies that are arranged around the first rotating body and revolve around the first axis as a result of the rotation of the first rotating body and that rotate around the second axis that is the respective axis. When,
A holding portion provided with an insertion hole into which a rotating portion rotating along the second axis in the second rotating body is inserted, and rotates around the first axis by the revolution of the second rotating body. A third rotating body;
A cylindrical member disposed between the inner periphery of the insertion hole and the outer periphery of the rotating portion, and having a linear expansion coefficient different from that of the holding portion and the rotating portion;
A reduction gear comprising: The speed reducer according to claim 1,
The linear expansion coefficient of the cylindrical member is a reduction device that is smaller than the linear expansion coefficients of the holding unit and the rotating unit. The speed reducer according to claim 2,
The speed reducing device, wherein the cylindrical member is metal, and the holding part and the rotating part are resin. The speed reducer according to claim 1,
A reduction device in which the elastic modulus of the cylindrical member is larger than the elastic modulus of the holding portion and the rotating portion. An actuator for generating a driving force;
A driving unit that transmits the driving force to the lens and drives the lens,
An optical apparatus comprising the speed reduction device according to any one of claims 1 to 4 between the drive unit and the actuator.

Images