JP6506015B2 - Friction reducer - Google Patents

Description

  The present invention relates to a friction reduction device, and more particularly to a friction reduction device in which two or more reduction gears are arranged in a cylindrical casing.

  In mechanical devices such as precision instruments and OA peripherals, there are many places where the rotational output of a small motor must be decelerated to a desired angular velocity range to transmit power. For example, in a device for driving a blind or a curtain, a multistage reducer is used in order to use a small and light electric motor. A multi-stage reduction gear is a reduction gear in which a plurality of reduction gears are arranged in a cylindrical casing, and decelerates and outputs the rotational force of an electric motor (for example, Patent Document 1).

  The planetary gear reducer described in Patent Document 1 is a reducer in which three stages of planetary gear units P1 to P3 are housed in a housing case 1. The planetary gear units P1 to P3 are configured by the sun gear 9, the planetary gear 5, and the planet carrier 4, and are coaxially arranged in a line. On the inner peripheral surface of the housing case 1, internal teeth common to the three-stage planetary gear units P1 to P3 are formed.

JP 2000-65165 A

  In the conventional multi-stage reduction gear as described above, although the transmission torque is largely different between the high speed rotating input shaft and the low speed rotating output shaft, the reduction gear of each stage has the same shape and size. It consists of Since the torque transmitted through the reduction gear increases as it gets to the latter stage, it is necessary to limit the torque input through the input shaft in order to prevent damage to the output reduction gear. For this reason, in the conventional multistage reducer, it was not possible to load a large torque on the output shaft.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a friction reduction gear capable of applying a large torque to an output shaft.

  The friction reduction gear according to the present invention comprises a cylindrical casing extending along a central axis extending in the vertical direction, two or more reduction gears arranged axially in the casing, and an input rotating about the central axis A shaft and an output shaft, and a pressure device for axially pressing the reduction gear with respect to the casing. The reduction gear is disposed on the outer periphery of the sun rolling element rotating about the central axis and radially outward of the sun rolling element, and is at least two in contact with the rolling surface of the sun rolling element and the inner circumferential surface of the casing. And a carrier rotatably supporting the planetary rolling element and rotating about the central axis. The sun rolling elements of the first stage reduction gear are connected directly or indirectly to the input shaft. The solar rolling element of the n-th gear reduction gear is connected to the carrier of the (n-1) -th gear reduction gear, where n is an integer of 2 or more. The carrier of the final stage reduction gear is connected directly or indirectly to the output shaft. The rolling surface of the sun rolling element is formed of a conical surface whose diameter decreases toward the output side. And the angle which the generatrix of the above-mentioned rolling surface in the n-th reduction gear makes to the above-mentioned central axis is smaller than the (n-1) -th reduction gear.

  Since the sun rolling element of the reduction gear is formed by a conical surface whose diameter decreases as the rolling surface moves toward the output side, the pressing wire of the reduction gear in the central axis direction causes the generatrix of the rolling surface to be reduced. A normal force can be applied to the planetary rolling elements according to the angle made with respect to the central axis. Further, in the n-th reduction gear, the angle formed is smaller than that of the (n−1) -th reduction gear. For this reason, in the n-th stage reduction gear, the sun rolling elements apply greater vertical reaction force to the planetary rolling elements, and can transmit larger torque than the (n-1) -th stage reduction gear.

  Since the friction reduction gear according to the present invention can transmit a larger torque as the reduction gear in the rear stage, it is possible to load a large torque on the output shaft.

FIG. 1 is a cross-sectional view of the friction reduction device 1 according to the first embodiment. FIG. 2 is a diagram showing the _n- th stage reduction gear device D _n and the (n-1) -th stage reduction gear device D _n-1 . FIG. 3 is a view showing the planetary rolling elements 32 of the reduction gear D _k of the k-th stage. FIG. 4 is a cross-sectional view of the friction reduction device 1 according to the second embodiment. FIG. 5 is a cross-sectional view of the friction reduction device 1 according to the third embodiment. FIG. 6 is a cross-sectional view of the friction reduction device 1 according to the fourth embodiment. FIG. 7 is a cross-sectional view of the friction reduction device 1 according to the fifth embodiment. FIG. 8 is a cross-sectional view of the friction reduction device 1 according to the sixth embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present specification, for convenience, the direction of the central axis is described as the vertical direction, but the posture during use of the friction reduction gear according to the present invention is not limited. Further, in the present specification, the direction of the central axis is simply referred to as “axial direction”, and the radial direction and circumferential direction about the central axis are simply referred to as “radial direction” and “circumferential direction”.

Embodiment 1
FIG. 1 is a cross-sectional view showing an example of the configuration of the friction reduction device 1 according to Embodiment 1 of the present invention, showing a cut surface when the friction reduction device 1 is cut by a plane including the central axis J There is. In this figure, the friction reduction gear 1 is drawn with the upper side of the paper surface as the output side and the lower side as the input side. Further, the reduction gear 3, the pressure device 6, the thrust bearing 7, the annular member 8, and the bearings 9 and 10 are drawn without breakage on the left side of the central axis J in FIG.

  The friction reduction gear 1 is a multi-stage reduction gear that decelerates and outputs rotational motion obtained from an electric motor (not shown), and the casing 2, two or more reduction gears 3, and a central axis J as a center It comprises a rotating input shaft 4 and output shaft 5, a pressure device 6, a thrust bearing 7, an annular member 8 and bearings 9 and 10.

The central axis J is a central axis of rotation of the reduction gear 3, the input shaft 4 and the output shaft 5, and is represented by a straight line extending in the vertical direction. Each reduction gear 3 is a reduction gear that transmits torque using frictional force, and is axially arranged in the casing 2. For example, when M is an integer of 3 or more, the friction reduction gear 1 is configured by reduction gears D _{1 to} D _M of M stages.

<Casing 2>
The casing 2 is a cylindrical housing extending along the central axis J. For example, the casing 2 is a covered cylindrical member, and includes a cylindrical portion 21, a cover plate 22, and a bottom plate 23. The inner circumferential surface 211 of the cylindrical portion 21 is formed of a cylindrical surface whose central axis is the central axis J.

  The lid plate portion 22 is constituted by a ring-shaped plate member which extends radially inward from the output-side end of the cylindrical portion 21 and which surrounds the output shaft 5. The bearing 10 is disposed radially inward of the inner circumferential surface 221 of the lid plate 22.

  The bottom plate portion 23 is formed of a ring-shaped plate member surrounding the input shaft 4, and is disposed at the input-side end of the cylindrical portion 21. The bottom plate portion 23 has a screw thread formed on the outer peripheral surface, and is fixed to the cylindrical portion 21 by being screwed to the inner peripheral surface of the cylindrical portion 21. A bearing 9 is disposed radially inward of the inner circumferential surface 231 of the bottom plate portion 23.

<Input axis 4 · Output axis 5>
The input shaft 4 is a drive-side rotation shaft directly or indirectly connected to the rotor or shaft of the electric motor. For example, the input shaft 4 is fixed to the shaft of the electric motor. Alternatively, the input shaft 4 is connected to the shaft of the electric motor via a power transmission device such as a gear. The output shaft 5 is a load side rotation shaft connected to a load. While the input shaft 4 rotates relatively at high speed, the output shaft 5 rotates at low speed.

  The bearing 9 is an input side bearing that supports the input shaft 4 rotatably with respect to the bottom plate portion 23. The bearing 10 is an output side bearing that rotatably supports the output shaft 5 with respect to the lid plate 22. For example, the bearings 9 and 10 are each configured by a ball bearing having the central axis J as a central axis. The bearing 9 is fixed to the bottom plate portion 23 by being fitted to the inner circumferential surface 231 from the output side. The bearing 10 is fixed to the lid plate 22 by being fitted to the inner circumferential surface 221 from the input side.

<Speed reduction gear 3>
The reduction gear 3 includes a sun rolling element 31 rotating around a central axis J, two or more planet rolling elements 32 in contact with the rolling surface of the sun rolling element 31 and the inner circumferential surface 211 of the casing 2, and a carrier 33. And two or more carrier pins 34. For example, three planetary rolling elements 32 are arranged at substantially equal intervals on the same circumference centering on the central axis J.

<Solar rolling element 31>
The sun rolling element 31 is a rotating member having an outer peripheral surface inclined with respect to the central axis J as a rolling surface. The rolling surface of the solar rolling element 31 is formed of a conical surface whose diameter decreases toward the output side. The sun rolling element 31 is constituted by a member having a truncated cone shape with the central axis J as a central axis, and the conical surface is a part of the side surface of a straight cone having an apex on the central axis J.

<Planet rolling element 32>
The planetary rolling element 32 is a rotating member having an outer circumferential surface inclined with respect to the central axis of rotation with respect to the carrier 33 as a rolling surface, and is disposed radially outside the solar rolling element 31. The planetary rolling elements 32 rotate on the carrier 33 by the frictional force applied from the sun rolling elements 31, and by the frictional force applied from the cylindrical portion 21 of the casing 2, the sun rolling elements 31 centered on the central axis J Revolve around the world.

<Carrier 33>
The carrier 33 is a support member that rotatably supports the planetary rolling element 32 and rotates around the central axis J. The carrier 33 rotatably supports the planetary rolling element 32 about a rotation center axis inclined with respect to the center axis.

  The carrier pin 34 is a rod-like member whose end on the input side passes through the planetary rolling element 32 and whose end on the output side is disposed in the carrier 33. Each planetary rolling element 32 is rotatably supported by the carrier 33 via the carrier pin 34.

  The output pin of the carrier pin 34 is fixed to the carrier 33. The planetary rolling element 32 rotates about the carrier pin 34. For example, a slide bearing, a needle roller bearing or a liner is disposed between the inner circumferential surface of the planetary rolling element 32 and the carrier pin 34.

Solar rolling elements 31 of the reduction gear D ₁ of the first stage is directly or indirectly connected to the input shaft 4. For example, the sun rolling element 31 of the reduction gear D ₁ is fixed to the input shaft 4. The carrier 33 of the final stage reduction gear device D _M is directly or indirectly coupled to the output shaft 5. For example, the carrier 33 of the reduction gear D _M is connected to the output shaft 5 through the pressure device 6.

Further, the n as any integer of 2 ≦ m ≦ M, solar rolling elements 31 of the reduction gear device D _n of the n stages are connected to the (n-1) reduction gear D _n-1 of the carrier 33 of the stage . For example, sun rolling elements 31 of the reduction gear _{D n} are integrally formed with the carrier 33 of the reduction gear device _{D n-1.} The reduction gears D _{1 to} D _M are each formed of a metal member. Further, a lubricant is filled in the casing 2. The lubricant is used to generate frictional force for transmitting torque between the rolling elements, to prevent wear of each member, and to cool each member.

<Pressing device 6>
The pressurizing device 6 is a pressure application device which axially pressurizes the reduction gear 3 to the casing 2. The pressure device 6 is constituted by a face cam that transmits torque and generates a load in the direction of the central axis J according to the transmission torque. For example, the pressure device 6 includes an input side cam ring 61 and an output side cam ring 63 surrounding the output shaft 5 and a plurality of spherical rolling elements 62 disposed between the input side cam ring 61 and the output side cam ring 63. .

Input side cam ring 61 is an annular member having a strip-shaped side is formed having an axial uneven along a circumference around the center axis J, is coupled to the carrier 33 in the speed reducer D _M of the final stage . On the other hand, the output side cam ring 63 is an annular member in which a belt-like side surface having unevenness in the axial direction is formed along a circumference centered on the central axis J, and is connected to the output shaft 5. The input side cam ring 61 and the output side cam ring 63 are disposed such that the belt-like side surfaces face each other.

Input side cam ring 61, by fitting a portion of the carrier 33 of the reduction gear D _M on the inner peripheral surface is fixed to the carrier 33. Carrier 33 of the reduction gear D _M, compared output shaft 5 is movable in the axial direction together with rotatable.

  A locking pin 64 is fixed to the output shaft 5. A distal end portion of the locking pin 64 protrudes from the outer peripheral surface of the output shaft 5 and is accommodated in an axially extending pin groove 65 formed on the inner peripheral surface of the output side cam ring 63. The rotation of the output cam ring 63 with respect to the output shaft 5 is limited by the locking pin 64. The output-side cam ring 63 has its output-side side surface in contact with the inner ring of the bearing 10, whereby the axial movement of the casing 2 is limited.

Input side cam ring 61, if the reduction gear device D _M from the carrier 33 torque is added in the direction of the normal force which is inclined with respect to the circumferential direction to add to the rolling elements 62. The output side cam ring 63 is rotated by the circumferential component of the load applied from the rolling element 62. On the other hand, the pressure device 6, the axial component of the normal force, to press the carrier 33 of the reduction gear D _M in the axial direction the input side.

The normal force that the cylindrical portion 21 of the casing 2 applies to the planetary rolling element 32 is radially inward and does not have an axial component. For this reason, the load F in the axial direction applied to the carrier 33 of the reduction gear device D _M by the pressurizing device 6 is equally applied to the carriers 33 of the other reduction gear devices D _{1 to} D _{M -1} .

<Thrust bearing 7>
The thrust bearing 7 is a bearing for receiving the load F in the axial direction by the pressing device 6 with respect to the casing 2 and can rotate the sun rolling element 31 of the first stage reduction gear D ₁ with respect to the bottom plate portion 23 To support. For example, the thrust bearing 7 is configured of an annular raceway plate surrounding the input shaft 4, a plurality of spherical rolling elements disposed between the raceway plates, and a holding member for holding the rolling bodies. The annular member 8 is a washer disposed between the thrust bearing 7 and the bottom plate portion 23.

FIG. 2 is an explanatory view showing a part of the friction reduction gear 1 of FIG. 1 in an enlarged manner, and an n- _th reduction gear D _n and an (n-1) _-th reduction gear D _n-1 It is shown. In this figure, the reduction gears D _n and D _n-1 are drawn in a state where the central axis J is turned horizontally.

The sun rolling element 31 of the n-th stage reduction gear D _n has an angle θ _n formed by the generatrix of the rolling surface 311 with respect to the central axis J compared to the (n−1) -th stage reduction gear D _n−1 small. In other words, the angle theta _n-1 solar rolling elements 31 of the angle theta _n and deceleration device _{D n-1} solar rolling element 31 of the reduction gear _{D n} satisfies the θ _n <θ _n-1.

Since the inner circumferential surface 211 of the casing 2 is a cylindrical surface extending in the axial direction, the rotation center axis J _k of the planetary rolling element 32 with respect to the carrier 33 is at the center axis J, where _k is an arbitrary integer of 1 or more and M or less. It is inclined against. That is, the carrier pin 34 is disposed to be inclined with respect to the central axis J.

Carrier pin 34 of the reduction gear device _{D n} of the n-stage angle phi _n which respect to the central axis J is the (n-1) is smaller than the reduction gear device _{D n-1} of the stage. That is, the angle phi _n constituting the rotation center axis _{J n} is the central axis J of the planetary rolling elements 32 of the reduction gear device _{D n,} the rotation center axis _{J n-1} of the speed reduction device _{D n-1} of the planetary rolling element 32 The angle φ _n-1 formed with respect to the central axis J satisfies φ _n <φ _n-1 . By configuring in this manner, as shown in the following paragraph 0039, it is possible to easily control the outer diameter shape of the reduction gear D _{1 to} D _M.

  The planetary rolling element 32 has an output side rolling surface 322 in contact with the rolling surface 311 of the sun rolling element 31 and an input side rolling surface 321 in contact with the inner circumferential surface 211 of the casing 2. The output side rolling surface 322 is formed of a conical surface whose diameter decreases toward the output side. On the other hand, the input side rolling surface 321 is formed of a conical surface whose diameter decreases toward the input side.

  Each of the input side rolling surface 321 and the output side rolling surface 322 is a part of a side surface of a right cone having an apex on the rotation center axis of the planetary rolling element 32 with respect to the carrier 33. In addition, the planetary rolling element 32 has a shape in which both cones are integrated by opposing the bottom surface of the conical surface forming the input side rolling surface 321 and the bottom surface of the conical surface forming the output side rolling surface 322.

The planetary rolling elements 32 of the n-th stage reduction gear device D _{n have} the width TR _n of the output side rolling surface 322 in contact with the sun rolling elements 31 be the planets of the (n-1) -th stage reduction gear D _{n -1} . Larger than rolling element 32. That is, the output side rolling surface 322 of the output-side rolling surface 322 and the speed reduction device _{D n-1} of the planetary rolling elements 32 of the planetary rolling elements 32 of the reduction gear _{D n is} met _{TR n>} TR _n-1 There is. The width TR _n of the output side rolling surface 322 is the length of the conical surface in the generatrix direction.

The width TF _n of the input side rolling surface 321 in contact with the inner circumferential surface 211 of the casing 2 is also similar to the width TR _n of the output side rolling surface 322. That is, the input side rolling surface 321 of the input-side rolling surface 321 and the speed reduction device _{D n-1} of the planetary rolling elements 32 of the planetary rolling elements 32 of the reduction gear _{D n is} met _{TF n>} TF _n-1 There is. The width TF _n of the input side rolling surface 321 is the length of the conical surface in the generatrix direction. Further, the width TF _k of the input side rolling surface 321 is smaller than the width TR _k of the output side rolling surface 322.

FIG. 3 is an explanatory view showing a part of the friction reduction device 1 of FIG. 1 in an enlarged manner, in which the planetary rolling elements 32 of the _k-th reduction gear D _k are shown. In this figure, the reduction gear _Dk is drawn in a state where the central axis J is turned horizontally.

Since the load F in the axial direction by the pressure device 6 is common to the reduction gears D _{1 to} D _M in the planetary rolling element 32 of the reduction gear D _k of the k-th stage, the normal force corresponding to the angle θ _k Q _k is added from the solar rolling element 31. Further, the deceleration device _{D n} of the n-stage, since the angle theta _n is smaller than the reduction gear device _{D n-1} of the (n-1) stages, the planetary rolling elements 32 of the reduction gear _{D n} is decelerating device A normal force Q _n greater than D _{n -1} is added.

The normal force _Qk and the normal force _Pk are applied to the planetary rolling elements 32 of the reduction gear _Dk of the k-th stage. The normal force Q _k is a normal force applied from the sun rolling element 31 to the output side rolling surface 322 of the planetary rolling element 32. On the other hand, the normal reaction force P _k is a normal force applied from the cylindrical portion 21 of the casing 2 to the input side rolling surface 321 of the planetary rolling element 32.

In this friction reduction gear 1, one or both of the action line of the normal reaction force P _{k and} the action line of the normal reaction force Q _k are the rotation center axis J _k of the planetary rolling element 32 with respect to the carrier 33 and the planetary rolling element 32. Cross inside. In particular, the line of action of the normal force Q _k and the line of action of the normal force P _k is, so as to intersect on the rotation center axis J _k, it is desirable to configure the planetary rolling element 32.

  Each component which comprises the friction reduction gear 1 by this Embodiment is as having mentioned above. In the following, the relationship between these parts and the effects produced thereby will be described in detail.

(1) Increase in Load Torque In the friction reduction gear 1 according to the present embodiment, since the rolling surface 311 of the solar rolling element 31 is formed of a conical surface that decreases in diameter toward the output side, By pressing the device D _k in the axial direction, a normal reaction force Q _k can be applied to the planetary rolling element 32 according to the angle θ _k formed by the generatrix of the rolling surface 311 with respect to the central axis J.

Further, the n-th gear reduction device D _n has an angle θ _n smaller than that of the (n−1) _-th gear reduction device D _n−1 . Therefore, reduction gear D _n of the n-stage, will be the sun rolling element 31 adds a larger normal force Q _n to the planetary rolling element 32, than the (n-1) reduction gear D _n-1 of the stage Can also transmit a large torque. Therefore, the friction reduction gear 1 can load the output shaft 5 with a large torque.

(2) Reduction of noise and vibration In the friction reduction device 1 according to the present embodiment, each reduction gear 3 transmits torque using frictional force, so vibration due to backlash and a reduction gear as compared to a gear reduction device Noise can be reduced.

  In the friction reduction gear 1, the planetary rolling element 32 rotates about the carrier pin 34. For this reason, the friction reduction gear 1 can suppress rattling and vibration of the planetary rolling element 32 as compared to a gear type reduction gear.

(3) Pressurization According to Load Torque In the friction gear 1 according to the present embodiment, the pressure device 6 is configured of a face cam that generates an axial load F according to the transmission torque. For this reason, the friction reduction gear 1 can press the reduction gears D _{1 to} D _M using a large transmission torque on the output side.

(4) Durability Improvement In the friction gear 1 according to the present embodiment, the width TR _k of the output-side rolling surface 322 of the planetary rolling element 32 increases as the transmission torque increases from the input side to the output side. For this reason, the friction reduction gear 1 can maintain the contact surface pressure between the sun rolling element 31 and the planetary rolling element 32 constant in each reduction gear 3. Therefore, the life of the reduction gear 3 on the output side can be prevented from being shortened due to wear or the like, and the durability of the friction reduction gear 1 can be improved.

(5) Simplification of Casing In the friction reduction gear 1 according to the present embodiment, the inner circumferential surface 211 of the casing 2 is formed of a cylindrical surface, and the input rolling is performed with the planetary rolling element 32 tilted with respect to the rotation center axis J _k It comprises the dynamic surface 321 and the output side rolling surface 322. For this reason, the friction reduction gear 1 can arrange the multistage reduction gear 3 in the casing 2 without complicating the configuration of the casing 2.

(6) Reduction of Transmission Loss In the friction gear 1 according to the present embodiment, since the action line of the normal reaction force P _{k and} the action line of the perpendicular reaction force Q _k intersect on the rotation center axis J _k , the planetary rolling elements The moments due to the normal forces P _k and Q _k applied to 32 are canceled out. For this reason, the friction reduction gear 1 can prevent an unnecessary load from being applied to a member for supporting the planetary rolling element 32, and the transmission loss is reduced.

  In the friction reduction gear 1, the planetary rolling element 32 rotates about the carrier pin 34. For this reason, as compared with the case where the carrier pin 34 is fixed to the planetary rolling element 32, the friction reduction device 1 can prevent the carrier pin 34 and the carrier 33 from being subjected to an extra load, and the transmission loss is reduced.

(7) Miniaturization of the friction reduction gear 1 In the friction reduction gear 1 according to the present embodiment, a large torque can be transmitted even if the reduction gear 3 on the output side has the same size as the reduction gear 3 on the input side. it can. For this reason, the friction reduction gear 1 can be miniaturized.

Further, in the friction reduction gear 1, the width TF _k of the input side rolling surface 321 is smaller than the width TR _k of the output side rolling surface 322. The contact range with the inner circumferential surface 211 of the casing 2 is wider in the circumferential direction than the contact range with the sun rolling element 31. Therefore, the input-side rolling surface 321, even if the width TF _k axial smaller than the output-side rolling surface 322, can be an output-side rolling surface 322 to obtain a contact pressure of the same degree. For this reason, the friction reduction gear 1 can reduce the size of the planetary rolling element 32 in the axial direction.

  In the present embodiment, although an example in which the pressure device 6 is disposed on the output side has been described, the present invention does not limit the arrangement of the pressure device 6 to this. For example, the pressure device 6 may be disposed on the input side.

Second Embodiment
In the first embodiment, an example in which all the reduction gears D _{1 to} D _M are formed of a metal member has been described. On the other hand, in this embodiment, s is an integer of 1 or more and (M-1) or less, and a case where the planetary rolling element 32 is formed of engineering plastic up to the reduction gear Ds of the sth stage will be described.

FIG. 4 is a cross-sectional view showing an example of the configuration of the friction reduction device 1 according to Embodiment 2 of the present invention, showing a cut surface when the friction reduction device 1 is cut by a plane including the central axis J There is. Compared with the friction reduction gear 1 of FIG. 1, this friction reduction gear 1 is provided with a partition 11 in the casing 2, and the planet rolling elements 32 of the _first reduction gear D1 are made of engineering plastic. It is different.

Engineering plastics are resins that have excellent mechanical strength and have enhanced specific functions such as heat resistance and abrasion resistance. Engineering plastics can transmit large torques without lubricants because they have a large coefficient of friction compared to metals. Planetary rolling elements 32 of the reduction gear device _D 2 to D _M of the second and subsequent stages is composed of a metallic member.

The partition wall 11 is a partition member for dividing the space in the casing 2 so that the lubricant does not move to the front side, and is constituted by the O-ring 111, the side plate 112, and the oil seal 113. Partition wall 11 is disposed between the reduction gear apparatuses D ₁ and reduction gear D _2, lubricant filled in the casing 2 is prevented from moving to the reduction apparatuses D ₁ side.

The side plate 112 is an annular member extending radially inward from the inner circumferential surface 211 of the cylindrical portion 21. The O-ring 111 is a seal member disposed between the inner circumferential surface 211 of the cylindrical portion 21 and the outer circumferential surface of the side plate 112. The oil seal 113 is a seal member disposed between the outer peripheral surface of the connecting portion 35 and the inner peripheral surface of the side plate 112. Connecting portion 35 is a cylindrical portion which connects the sun rolling elements 31 of the reduction gear D ₂ and the carrier 33 of the reduction gear D _1.

In the friction reduction gear 1 according to the present embodiment, the first speed reduction gear D ₁ does not require a lubricant. For this reason, since the friction reduction gear 1 can reduce the normal force Q with respect to the same load torque, the rolling resistance can be reduced, and the transmission loss can be reduced.

Third Embodiment
In the first embodiment, an example in which the casing 2 has a substantially equal diameter in the axial direction has been described. On the other hand, in the present embodiment, the case where two or more reduction gears 3 are disposed in the casing 2 whose diameter changes in the middle in the axial direction will be described.

FIG. 5 is a cross-sectional view showing an example of a configuration of the friction reduction device 1 according to Embodiment 3 of the present invention, in which a cut surface when the friction reduction device 1 is cut by a plane including the central axis J is shown There is. The friction reducer 1, if compared to the friction reducer 1 in FIG. 1, a reduced diameter between the cylindrical portion 21 of the casing 2 between the reduction gear D ₂ of the second stage and a deceleration device D ₁ of the first stage Differ in that they

The cylindrical portion 21 of the casing 2 is configured of a large diameter portion 213 and a small diameter portion 212 having mutually different diameters. The large diameter portion 213 has a larger inner diameter than the small diameter portion 212. The reduction gear D ₁ is disposed radially inward of the small diameter portion 212. The reduction gear devices D _{2 to} D _{M in} the second and subsequent stages are disposed radially inward of the large diameter portion 213, and the size thereof is increased.

  In the friction reduction gear 1 according to the present embodiment, the reduction gear 3 in the rear stage can be upsized by using the casing 2 whose inner diameter has changed. If the size of the reduction gear 3 is increased, a larger torque can be transmitted, so the friction reduction gear 1 can load the output shaft 5 with a larger torque.

  In Embodiments 1 to 3, an example in which the pressing device for pressing the reduction gear 3 in the axial direction with respect to the casing 2 is configured by the face cam has been described. On the other hand, in the following fourth and fifth embodiments, the case where the decelerating device 3 is axially pressed using the biasing force of the elastic body will be described. Further, in the sixth embodiment, the case where the reduction gear 3 is axially pressurized using the magnetic bias of the electric motor will be described.

Fourth Embodiment
FIG. 6 is a cross-sectional view showing one configuration example of the friction reduction device 1 according to the fourth embodiment of the present invention, and shows a cut surface when the friction reduction device 1 is cut by a plane including the central axis J There is. In this friction reduction gear 1, as compared with the friction reduction gear 1 of FIG. 1, the pressurizing device is constituted by the coil spring 12 and the inner circumferential surface 214 where the cylindrical portion 21 of the casing 2 is inclined with respect to the central axis J Furthermore, it differs in that the planetary rolling elements 32 of the reduction gear device D _M of the final stage have a rolling surface parallel to the central axis of rotation with respect to the carrier 33.

The coil spring 12 urges the solar rolling element 31 of the first stage reduction gear device D ₁ to the axial direction output side, whereby the reduction gear devices D _{2 to} D _M of the _{second and} subsequent stages are axially directed to the casing 2. Is a pressure device that applies pressure to the The coil spring 12 is an elastic body that generates a biasing force in the direction of the central axis J according to the amount of deformation, and is constituted by a helical spring surrounding the input shaft 4. Coil spring 12 is disposed between the solar rolling element 31 and the bearing 9 of the reduction gear D _1.

The inner peripheral surface 214 of the cylindrical portion 21 is an inner peripheral surface in contact with the rolling surface of the planetary rolling elements 32 in the speed reducer D _M of the final stage, constituted by the conical surface whose diameter is reduced toward the output side. That is, the inner circumferential surface 214 has a central axis J as a central axis, and is constituted by a part of the side surface of a right cone having an apex on the central axis J.

Planetary rolling elements 32 of the reduction gear D _M of the final stage, has an outer peripheral surface parallel to the central axis of rotation relative to the carrier 33 as a rolling surface, with the rolling surface is in contact with the solar rolling element 31, the cylindrical portion 21 In contact with the inner circumferential surface 214 of the That is, the rolling surface of the planetary rolling elements 32 of the reduction gear D _M is constituted by a cylindrical surface whose central axis coincides with the rotation center axis relative to the carrier 33.

Angle between the rotation center axis relative to the central axis J relative to the carrier 33 of the planetary rolling elements 32 of the reduction gear D _M is the generating line of the sun rolling elements 31 of the reduction gear D _M coincides with an angle formed with respect to the central axis J . Therefore, the inner circumferential surface 214 and the rolling surface of the solar rolling elements 31 of the reduction gear D _M of the cylindrical portion 21, are parallel to each other.

Planetary rolling elements 32 of the reduction gear device other than the final stage D ₁ ~D _M-1 has a peripheral surface which is inclined with respect to the central axis of rotation relative to the carrier 33 as the rolling surface. The carrier 33 of the reduction gear D _M of the last stage is coupled to the output shaft 5 via a key or serrations. That is, the carrier 33 of the reduction gear D _M, to the output shaft 5, while the rotation in the circumferential direction is restricted is movable in the axial direction.

In the friction reduction gear 1 according to the present embodiment, it is possible to simplify the pressure device for axially pressing the reduction gear 3 with respect to the casing 2. Moreover, the load that is added to the speed reduction device 3 by the pressure device, is received in the inner peripheral surface 214 of the casing 2 is in contact with the reduction gear D _M of the final stage. For this reason, the friction reduction gear 1 can suppress that the load of the direction of the central axis J acts on the output shaft 5 and the bearing 10 which supports the output shaft 5, and a transmission loss reduces.

  In the present embodiment, an example in which the pressing device for pressing the reduction gear 3 in the axial direction with respect to the casing 2 is configured by the coil spring 12 has been described, but the present invention relates to the pressing device. It is not limited to For example, in place of the coil spring 12, the friction reduction device 1 biases the reduction gear 3 in the axial direction using a disc spring or a plate spring, or uses the elastic force of rubber to axially reduce the reduction gear 3. It may be configured to be biased.

Moreover, although the example in the case where the coiled spring 12 is arrange | positioned at the input side was demonstrated in this Embodiment, this invention does not limit arrangement | positioning of elastic bodies, such as a coiled spring, to this. For example, the friction reducer 1 is placed on the output side of the elastic body, the carrier 33 of the reduction gear D _M of the final stage may be configured to bias the axial direction the input side.

Embodiment 5
FIG. 7 is a cross-sectional view showing one configuration example of the friction reduction device 1 according to the fifth embodiment of the present invention, and shows a cut surface when the friction reduction device 1 is cut by a plane including the central axis J There is. The friction reducer 1, if compared to the friction reducer 1 in FIG. 1, the pressurizing device 13 is constituted by an annular member 131 and the coil spring 132, the planetary rolling elements 32 of the reduction gear D _M at the final stage carrier 33 And the rolling surface parallel to the rotation center axis.

The annular member 131, the planetary rolling elements 32 of the reduction gear D _M and the outer circumference, a internal ring having a peripheral surface 133 inner inclined relative to the central axis J. The inner peripheral surface 133 of the annular member 131 is an inner peripheral surface in contact with the rolling surface of the planetary rolling elements 32 in the speed reducer D _M, constituted by a conical surface whose diameter is reduced toward the output side. That is, the inner circumferential surface 133 has a central axis J as a central axis, and is constituted by a part of the side surface of a right cone having an apex on the central axis J.

The inner circumferential surface 133 and the rolling surface of the solar rolling elements 31 of the reduction gear D _M of the annular member 131, are parallel to each other. The annular member 131 is accommodated in the cylindrical portion 21 of the casing 2 and is movable in the axial direction. In addition, the rotation of the annular member 131 with respect to the casing 2 is limited by a rotation preventing member such as a spline or a key.

Coil spring 132, by urging the annular member 131 in the axial direction the input side, to the casing 2, pressurizing the reduction gear _D 1 to D _M in the axial direction. The coil spring 132 is an elastic member that generates a biasing force in the direction of the central axis J in accordance with the deformation amount, constituted by helical spring surrounding the carrier 33 of the reduction gear D _M. The coil spring 132 is disposed between the lid plate 22 of the casing 2 and the annular member 131.

With planetary rolling elements 32 of the reduction gear D _M of the final stage, has an outer peripheral surface parallel to the central axis of rotation relative to the carrier 33 as a rolling surface, the rolling surface is in contact with the solar rolling element 31, the annular member 131 Contact the inner circumferential surface 133 of the Planetary rolling elements 32 of the reduction gear device other than the final stage D ₁ ~D _M-1 has a peripheral surface which is inclined with respect to the central axis of rotation relative to the carrier 33 as the rolling surface. The carrier 33 of the reduction gear D _M of the final stage is fixed to the output shaft 5.

  The friction reduction gear 1 according to the present embodiment can generate a larger load F than the friction reduction gear 1 of FIG. 6, so that a large load torque can be transmitted.

Sixth Embodiment
FIG. 8 is a cross-sectional view showing one configuration example of the friction reduction device 1 according to the sixth embodiment of the present invention, showing a cut surface when the friction reduction device 1 is cut by a plane including the central axis J There is. Compared with the friction reduction gear 1 of FIG. 1, the friction reduction gear 1 is constituted by the electric motor 14 that generates a magnetic bias in the axial direction, and the cylindrical portion 21 of the casing 2 with respect to the central axis J has an inner peripheral surface 214 which is inclined Te, further, it differs in that the planetary rolling elements 32 of the reduction gear D _M of the final stage has a parallel rolling surface to the rotation center axis relative to the carrier 33.

  The electric motor 14 is an inner rotor type electric motor including a shaft 141, a rotor 142, a stator 143 and a housing 144. The rotor 142 is fixed to the shaft 141 and rotates with the shaft 141 about the central axis J. The stator 143 encloses the rotor 142 and is fixed to the housing 144.

  The housing 144 accommodates the shaft 141, the rotor 142, the stator 143, the housing 144 and the radial bearing 145. The radial bearing 145 is a bearing for receiving a radial load, and rotatably supports the shaft 141 with respect to the housing 144. The radial bearing 145 is disposed below the rotor 142. The shaft 141 is axially movable with respect to the radial bearing 145.

  The electric motor 14 is attached to the casing 2 by fitting the upper end portion of the housing 144 into the inner peripheral surface 211 of the cylindrical portion 21 of the casing 2. Accordingly, the stator 143 is fixed to the casing 2 via the housing 144. The input shaft 4 is connected to the shaft 141 directly or indirectly. For example, the input shaft 4 is integrally formed with the shaft 141. The rotor 142 is coupled to the input shaft 4.

In the electric motor 14, the rotor 142 is arranged to be shifted from the stator 143 in the direction opposite to the reduction gears D _{1 to} D _M in the direction of the central axis J. That is, in the electric motor 14, the central portion in the axial direction of the rotor 142 is located axially lower than the central portion in the axial direction of the stator 143. For this reason, the electric motor 14 generates an electromagnetic force which is an electromagnetic force acting on the rotor 142 from the stator 143 and which has a component directed upward in the axial direction as a magnetic bias. The magnetic bias changes according to the position of the rotor 142 in the direction of the central axis J. Therefore, the electric motor 14 generates an axial magnetic bias according to the position of the rotor 142 in the direction of the central axis J.

  In the friction reduction gear 1 according to the present embodiment, since the reduction gear 3 is axially pressurized using the magnetic bias of the electric motor 14, it is not necessary to separately provide a pressure device.

In the first to sixth embodiments, an example has been described of the case where the solar rolling element 31 of the reduction gear device D _n is decelerated device D _n-1 of the carrier 33 formed integrally with, the present invention is the reduction gear transmission The configuration of D _k is not limited to this. For example, the sun rolling elements 31 of the reduction gear device _{D n} is formed by a separate member from the speed reduction device _{D n-1} of the carrier 33, the sun rolling elements 31 of the reduction gear device _{D n} and the carrier 33 of the reduction gear device _{D n-1} It may be configured to be connected.

Also, in the first to sixth embodiments, an example in which the friction reduction gear 1 is configured by the reduction gear 3 of three or more stages has been described, but in the present invention, the friction reduction gear 1 is a two-stage reduction gear It can apply also to what is comprised. Further, the present invention than the deceleration device D _M of the final stage can be applied to the friction reducer having a planetary gear type reduction gear to a subsequent stage.

1 Friction reduction gear 2 casing 21 cylindrical portion 211, 214 inner peripheral surface 22 the cover plate 23 the bottom plate _{3, D k, D 1 ~D} M reduction gear 31 sun rolling element 32 planetary rolling element 321 input side rolling surface 322 Output Side rolling surface 33 Carrier 34 Carrier pin 35 Coupling part 4 Input shaft 5 Output shaft 6 Pressure device 61 Input side cam ring 62 Rolling element 63 Output side cam ring 64 Locking pin 65 Pin groove 7 Thrust bearing 8 Annular member 9, 10 Bearing 11 of the partition wall 111 O-ring 112 side plate 113 oil seal 12 coil spring 13 pressing device 131 annular member 132 coil spring 14 electric motor 141 shaft 142 rotor 143 stator 144 housing 145 radial bearing J central axis _J k, _{J n} planetary rolling elements 32 Central axis of rotation P _k , Q _k normal force

Claims (13)

A cylindrical casing extending along a central axis extending in the vertical direction, two or more reduction gears axially arranged in the casing, an input shaft and an output shaft rotating about the central axis, and the casing And a pressing device for pressing the reduction gear in the axial direction, wherein the reduction gear is disposed radially outside of the sun rolling element rotating around the central axis, and the solar rolling element. There are two or more planet rolling elements in contact with the rolling surface of the sun rolling element and the inner circumferential surface of the casing, and a carrier that rotatably supports the planetary rolling elements and rotates around the central axis. The solar rolling element of the first stage reduction gear is directly or indirectly connected to the input shaft, and the solar rolling element of the nth stage reduction gear (n is an integer of 2 or more) is (N – 1) -speed reduction gear The carrier of the final stage reduction gear is connected directly or indirectly to the output shaft, and the rolling surface of the solar rolling element is a conical surface whose diameter decreases toward the output side. A friction reduction gear, wherein the angle formed by the generatrix of the rolling surface in the n-th gear reduction device is smaller than that of the (n-1) -th gear reduction device. The planetary rolling elements of the n-th stage reduction gear are characterized in that the width in the generatrix direction of the rolling surface in contact with the sun rolling elements is larger than the planetary rolling elements of the (n-1) -th stage reduction gear The friction reducer according to claim 1. The planetary rolling elements of the reduction gear at least other than the final stage have an output side rolling surface in contact with the rolling surface of the sun rolling element and an input side rolling surface in contact with the inner peripheral surface of the casing. The output side rolling surface is composed of a conical surface whose diameter decreases toward the output side, and the input side rolling surface is composed of a conical surface whose diameter decreases toward the input side. A friction reduction gear according to claim 1 or 2. Either or both of the action line of the normal force applied from the sun rolling element to the output side rolling surface and the action line of the normal force applied from the casing to the input side rolling surface are the carrier The friction reduction gear according to claim 3, wherein a rotation center axis of the planetary rolling element with respect to and intersects in the planetary rolling element. The action line of the normal force applied from the sun rolling element to the output side rolling face and the action line of the normal force applied from the casing to the input side rolling face correspond to those of the planetary rolling element with respect to the carrier. The friction reducer according to claim 4, wherein the friction reducer intersects on the rotation center axis. The reduction gear has two or more carrier pins whose output side end is disposed in the carrier and whose input side end penetrates the planetary rolling element, and the carrier pin is relative to the central axis The carrier pin of the n-th stage reduction gear, which is disposed inclined, is characterized in that the angle formed with respect to the central axis is smaller than that of the (n-1) -th stage reduction gear. Friction reducer according to any one of. The friction reduction gear according to claim 6, wherein the carrier pin has an output end fixed to the carrier, and the planetary rolling element rotates about the carrier pin. The casing has an inner circumferential surface that is in contact with the rolling surface of the planetary rolling element in the final stage reduction gear and has an inner circumferential surface configured by a conical surface whose diameter decreases toward the output side. The friction reduction gear in any one of Claims 1-7. The friction reducer according to any one of claims 1 to 8, wherein the pressurizing device is constituted by a face cam that transmits a torque and generates a load in the central axis direction according to the transmission torque. . The friction reducer according to claim 9, wherein the pressure device has an input side cam ring connected to the carrier in a final stage reduction gear, and an output side cam ring connected to the output shaft. The friction reduction gear according to any one of claims 1 to 8, wherein the pressure device is formed of an elastic body that generates an urging force in the central axis direction according to a deformation amount. The stator has an electric motor fixed directly or indirectly to the casing and a rotor connected to the input shaft, the rotor being axially central with respect to the axial central portion of the stator Are disposed on the opposite side of the reduction gear in the axial direction, and the pressure device is constituted by the electric motor generating a magnetic bias in the central axis direction according to the position of the rotor in the central axis direction. The friction reducer according to any one of claims 1 to 8, characterized in that: It has an annular member having an inner circumferential surface which is an inner circumferential surface in contact with the rolling surface of the planetary rolling element in the final stage reduction gear and which is formed of a conical surface whose diameter decreases toward the output side, The friction reduction gear according to any one of claims 1 to 7 , wherein the pressing device is configured by a biasing member that biases the annular member toward the input side in the central axis direction.

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