JP2016070285A - Speed reducer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a speed reducer capable of reducing load applied to a wheel member added to a frictional member.SOLUTION: A speed reducer 1 is constituted by a sun rolling member 11; two or more planetary rolling members 12; a carrier pin 13 rotatably supporting the planetary rolling members 12; a wheel member 14 rotatably supporting two or more planetary rolling members 12; an annular rolling member 2 outwardly enclosing two or more planetary rolling members 12 so as to cause the planetary rolling members 12 to be rotated around a rotating center axis J1 through contact with the planetary rolling members 12; a casing member 16 outwardly enclosing the sun rolling member 11 and the planetary rolling members 12 to support the rolling members 12; and a bearing 17 for rotatably supporting the wheel member 14 in respect to the casing member 16. The bearing includes the output bearing 17 arranged between an inner peripheral surface of the casing member 16 and a carrier pin supporting part 141; and a wheel bearing 18 arranged between an outer peripheral surface of the casing member 16 and an inner peripheral surface of a cylindrical part 162.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a reduction gear, and more specifically, a solar rolling element, a planetary rolling element, and a wheel member that rotate about a rotation center axis, respectively, and an annular rolling member that surrounds a plurality of planetary rolling elements. The present invention relates to an improvement of a reduction gear provided.

  A reduction gear that decelerates the rotational motion obtained from an electric motor is used to increase the torque and rotate the wheels at a desired speed in a self-propelled vehicle such as an electric wheelchair or AGV (automated guided vehicle) ( For example, Patent Document 1). In addition, there is a wheel-in-drive type wheel drive device in which a reduction mechanism, an electric motor, and an electromagnetic brake are incorporated in a wheel by miniaturizing a power transmission mechanism (for example, Patent Document 2).

JP 2003-28254 A JP 2008-17588 A

  In the conventional speed reducer, since the load applied to the wheel that holds the tire directly acts on the friction member in the speed reducer, the transmission performance of the speed reducer may be reduced. For example, in the friction roller type speed reducer 6 described in Patent Document 1, a load applied to the support cylinder portion 4 of the wheel 1 is directly applied to the outer ring 32 that contacts the guide rollers 37 a and 37 b and the wedge roller 38. For this reason, since the outer ring 32, the guide rollers 37a and 37b, the wedge roller 38, and the shaft between the rotary drive shaft 17 and the friction member are touched, the transmission performance is lowered, and the life of these friction members is shortened.

  Further, in the planetary gear type speed reducer 103 described in Patent Document 2, a load related to the first layer member 41 of the wheel 104 is directly applied to the second internal gear 27 that meshes with the second planetary gear 28. For this reason, the meshing part between the second internal gear 27, the second planetary gear 28, and the second sun gear 26 becomes irregular, which causes vibration and noise.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a speed reducer that can reduce the load applied to the wheel member from being applied to the friction member.

  The reduction gear device according to the present invention is arranged with a solar rolling element that rotates about a rotation center axis and a radially outer side than the solar rolling element, and rotation is transmitted by contact with the solar rolling element 2. The above planetary rolling element, a carrier pin that rotatably supports the planetary rolling element, a wheel member that rotatably supports the two or more planetary rolling elements and rotates about the rotation center axis, and the two or more An annular rolling member that rotates the planetary rolling element around the rotation center axis by surrounding the planetary rolling element and contacting the planetary rolling element, and the solar rolling element and the planetary rolling element. It is comprised by the casing member which encloses and supports the said rolling member, and the bearing which supports the said wheel member rotatably with respect to the said casing member. The wheel member includes a carrier pin supporting portion that supports the carrier pin, a connecting portion that extends radially outward from the carrier pin supporting portion, and an outer edge of the connecting portion along an outer peripheral surface of the casing member. And a cylindrical portion extending. The bearing is an output bearing disposed between the inner peripheral surface of the casing member and the carrier pin support portion, and a wheel disposed between the outer peripheral surface of the casing member and the inner peripheral surface of the cylindrical portion. Including bearings.

  The wheel member is supported by the casing member via the output bearing and the wheel bearing. In particular, the cylindrical portion of the wheel member extends along the outer peripheral surface of the casing member, and is supported by the casing member via a wheel bearing disposed between the outer peripheral surface of the casing member. Moreover, since the rolling member which contacts a planetary rolling element is supported by a casing member, the load concerning a wheel member is not added directly.

  In the speed reducer according to the present invention, since the load on the rolling member that contacts the planetary rolling element is reduced, the load applied to the wheel member is applied to the friction member constituted by the solar rolling element, the planetary rolling element, and the rolling member. The addition can be reduced.

FIG. 1 is a cross-sectional view of a reduction gear device 10 according to an embodiment. FIG. 2 is an explanatory view of the inside of the reduction gear device 10 as viewed from the output side. FIG. 3 is an explanatory diagram schematically showing an example of a detailed configuration of the reduction gear 10.

  Embodiments of the present invention will be described below with reference to the drawings. In this specification, for the sake of convenience, the direction of the rotation center axis of the solar rolling element will be described as a horizontal direction, but the posture of the reduction gear according to the present invention is not limited. Further, in this specification, the direction of the rotation center axis of the solar rolling element is simply referred to as “axial direction”, and the radial direction and the circumferential direction around the rotation center axis are simply referred to as “radial direction” and “circumferential direction”. .

  FIG. 1 is a cross-sectional view showing a configuration example of a wheel drive device 1 including a speed reduction device 10 according to an embodiment of the present invention, in which a part of the wheel drive device 1 is cut by a plane including a rotation center axis J1. The cut surface of the case is shown. In FIG. 1, a cut surface of the reduction gear device 10 is drawn. In FIG. 1, the planetary roller 12 positioned above the sun roller 11 on the paper surface is drawn without being cut. FIG. 2 is an explanatory view of the inside of the speed reducer 10 as viewed from the output side. The wheel member 14 and the casing member 16 are partially broken, and the sun roller 11, the planetary roller 12, the carrier pin 13, and the internal ring. 15 is shown.

  The wheel driving device 1 is a wheel-in-drive type driving device that rotates a wheel of a self-propelled vehicle, and includes a speed reduction device 10, an electric motor 20, and an electromagnetic brake 30. The electric motor 20 is a motor that outputs torque using electric power. The speed reducer 10 is a speed reducer that decelerates the rotational motion obtained by the electric motor 20. The electromagnetic brake 30 is a braking device that obtains a braking force using the attractive force of the electromagnet, and brakes the rotational motion of the electric motor 20.

  The reduction gear device 10 is disposed on one end side of a shaft (not shown) of the electric motor 20, and the electromagnetic brake 30 is disposed on the other end side of the shaft. For example, the electric motor 20 is an outer rotor type motor having a cylindrical housing.

  The speed reducer 10 is a friction type speed reducer that transmits rotation using frictional force, and includes a wheel cover 4, an input bearing 5, a sun roller 11, a planetary roller 12, a carrier pin 13, a wheel member 14, an internal ring. 15, a casing member 16, an output bearing 17, a wheel bearing 18, an encoder 19, and an urging member 153. Hereinafter, each of these components will be described in detail.

<Sun Roller 11>
The sun roller 11 is a solar rolling element that rotates around the rotation center axis J1. The sun roller 11 is composed of a cylindrical metal member extending in the axial direction, is formed integrally with the shaft of the electric motor 20, and is arranged coaxially with the shaft. The outer peripheral surface of the sun roller 11 is a rolling surface that comes into contact with the planetary roller 12. For example, the sun roller 11 is formed on the shaft of the electric motor 20 itself. The reduction gear 10 may be configured such that the sun roller 11 is formed by a member different from the shaft of the electric motor 20 and is fixed to the shaft.

  The sun roller 11 is rotatably supported with respect to the casing member 16 by the input bearing 5. The input bearing 5 is a bearing that rotatably supports the sun roller 11. For example, the input bearing 5 is a ball bearing.

<Planetary roller 12>
The planetary roller 12 is a planetary rolling element that is disposed radially outward from the sun roller 11 and transmits rotation by contacting the outer peripheral surface of the sun roller 11, and rotates around the rotation axis J2. , Revolving around the rotation center axis J1. The outer peripheral surface of the planetary roller 12 is a rolling surface that contacts the sun roller 11 and the internal ring 15. The planetary roller 12 includes a large diameter part 121 and a small diameter part 122 having different diameters.

  The large diameter portion 121 is made of a disk-shaped metal member centered on the rotation axis J <b> 2 and is in contact with the outer peripheral surface of the sun roller 11. The outer peripheral surface of the large-diameter portion 121 is configured by a cylindrical surface having a diameter larger than that of the small-diameter portion 122 and having a constant diameter in the axial direction.

  The small-diameter portion 122 is configured by a truncated cone-shaped metal member centered on the rotation axis J <b> 2 and contacts the inner peripheral surface of the internal ring 15. The small diameter part 122 is formed on the electric motor 20 side and the opposite side of the electric motor 20 with the large diameter part 121 sandwiched in the axial direction.

  The small-diameter portion 122 on the electric motor 20 side and the small-diameter portion 122 on the opposite side of the electric motor 20 each have an outer peripheral surface whose diameter decreases as the distance from the large-diameter portion 121 increases in the axial direction. That is, the small diameter portion 122 has an outer peripheral surface constituted by an inclined surface having a constant inclination angle. The inclination angle of the outer peripheral surface is, for example, 45 °.

  For example, the speed reducer 10 includes three planetary rollers 12 arranged around the sun roller 11. These planetary rollers 12 are arranged at a substantially constant interval in the circumferential direction. Each planetary roller 12 is arranged with its rotation axis J2 facing the same direction as the rotation center axis J1.

<Wheel member 14>
The wheel member 14 is a carrier member that rotatably supports the three planetary rollers 12 via the carrier pins 13 and rotates about the rotation center axis J1. The carrier pin 13 is a roller shaft that rotatably supports the planetary roller 12. The carrier pin 13 is a cylindrical metal member that extends in the same direction as the rotation center axis J <b> 1 and is held by the wheel member 14.

  One end side of the carrier pin 13 is held by the wheel member 14, and the planetary roller 12 is disposed on the other end side. For example, the planetary roller 12 is supported by the carrier pin 13 via a sliding bearing 123 accommodated in a pin hole penetrating in the axial direction.

  The wheel member 14 has a bottomed cylindrical shape and includes a carrier pin support portion 141, a connecting portion 142, a cylindrical portion 143, and a lid plate portion 144. The carrier pin support part 141, the connecting part 142, and the lid plate part 144 constitute a bottom part 145 of the wheel member 14.

  The carrier pin support part 141 supports the carrier pin 13. The carrier pin support portion 141 is provided for each planetary roller 12. The connecting portion 142 has a shape extending radially outward from the carrier pin support portion 141, connects the carrier pin support portion 141 and the cylindrical portion 143, and connects the three carrier pin support portions 141 to each other.

  The cylindrical portion 143 has a shape extending in the axial direction from the outer edge portion of the connecting portion 142 along the outer peripheral surface of the casing member 16. The cylindrical portion 143 is a wheel that holds the tire 2. The cover plate portion 144 has a disk shape that faces the end face of the sun roller 11, and is disposed radially inward from the carrier pin support portion 141.

<Internal ring 15>
The internal ring 15 is an annular rolling member that surrounds the three planetary rollers 12 and rotates the planetary rollers 12 around the rotation center axis J1 by contacting the planetary rollers 12. Supported. The internal ring 15 has an annular inner peripheral surface, and the inner peripheral surface is brought into contact with the outer peripheral surface of the small diameter portion 122 of the planetary roller 12.

  The internal ring 15 includes an output side ring 151 and an input side ring 152, and is arranged on the electric motor 20 side and the opposite side of the electric motor 20 with respect to the large diameter portion 121 of the planetary roller 12. The output side ring 151 and the input side ring 152 are both opposed to the large diameter portion 121 in the axial direction, and the shape of the cut surface when cut by a plane including the rotation center axis J1 is substantially rectangular.

  The output side ring 151 is an internal ring arranged on the side opposite to the electric motor 20, and is arranged with the annular side surface facing the side surface of the large diameter portion 121. The input side ring 152 is an internal ring disposed on the electric motor 20 side, and is disposed with the annular side surface facing the side surface of the large diameter portion 121.

  The sun roller 11, the planetary roller 12, and the internal ring 15 constitute a friction member. Since the outer peripheral surface of the large diameter portion 121 of the planetary roller 12 has a larger diameter than the outer peripheral surface of the sun roller 11, the rotation of the sun roller 11 is decelerated by the planetary roller 12. Further, since the inner peripheral surface of the internal ring 15 has a larger diameter than the outer peripheral surface of the small diameter portion 122 of the planetary roller 12, the rotation of the planetary roller 12 is further decelerated by the internal ring 15.

<Casing member 16>
The casing member 16 is a rolling member support member that surrounds the sun roller 11 and the planetary roller 12 and supports the internal ring 15, and is fixed to the housing of the electric motor 20. The casing member 16 has a cylindrical shape with a lid, and includes a lid plate portion 161, a cylindrical portion 162, and a bearing housing portion 163.

  The lid plate portion 161 is constituted by a disc-like lid member having a through hole for accommodating the input bearing 5 in the central portion with the rotation center axis J1 as the center. The lid plate portion 161 is attached to the housing of the electric motor 20. The cylindrical portion 162 has a shape extending in the axial direction from the outer edge portion of the lid plate portion 161 and accommodates the internal ring 15. The bearing accommodating portion 163 has a shape extending radially inward from the cylindrical portion 162 on the opening side of the casing member 16 and accommodates the output bearing 17.

<Output bearing 17 / wheel bearing 18>
The output bearing 17 and the wheel bearing 18 are bearings that rotatably support the wheel member 14 with respect to the casing member 16. The output bearing 17 is a bearing that rotatably supports the bottom portion 145 of the wheel member 14, and is disposed between the inner peripheral surface of the casing member 16 and the carrier pin support portion 141. The output bearing 17 is, for example, a ball bearing, and is disposed between the inner peripheral surface of the bearing housing portion 163 and the outer peripheral surface of the carrier pin support portion 141.

  The wheel bearing 18 is a bearing that rotatably supports the cylindrical portion 143 of the wheel member 14, and is disposed between the outer peripheral surface of the casing member 16 and the inner peripheral surface of the cylindrical portion 143. The wheel bearing 18 is a bearing having a larger diameter and a greater load resistance than the output bearing 17, and is disposed on the opening side of the wheel member 14. The wheel bearing 18 is, for example, a ball bearing. The speed reducer 10 may be configured to use a rolling bearing other than a ball bearing, for example, a roller bearing, for the output bearing 17 and the wheel bearing 18.

<Biasing member 153>
The biasing member 153 is a pressure member that biases the internal ring 15 in the axial direction with respect to the casing member 16 in order to adjust the frictional force between the friction members, and the output side ring 151 of the internal ring 15. Alternatively, the input side ring 152 is biased toward the large diameter portion 121 of the planetary roller 12.

  The biasing member 153 is configured using an elastic material, and is disposed on the outer edge portion of the lid plate portion 161 of the casing member 16 to bias the input side ring 152. For example, the urging member 153 is configured by a coil spring having a central axis extending in the axial direction. There may be a plurality of urging members 153. Two or more urging members 153 are used in the speed reduction device 10.

  The cover plate portion 161 and the bearing housing portion 163 of the casing member 16 restrict the internal ring 15 from moving in the axial direction. Further, the inclination of the outer peripheral surface of the small diameter portion 122 is such that the radial force that presses the large diameter portion 121 against the sun roller 11 is increased by urging the input side ring 152 of the internal ring 15 in the axial direction. Works. The frictional force between the friction members is adjusted by controlling the biasing force of the biasing member 153.

<Encoder 19>
The encoder 19 is a detection device that detects the rotation of the wheel member 14. For example, the encoder 19 is a transmissive optical rotary encoder that optically detects the rotation of the wheel member 14, and includes a sensor unit 191 and a slit plate 192.

  The sensor unit 191 is fixed to the casing member 16 and generates a detection signal indicating the rotation speed of the wheel member 14 by reading the slit plate 192. The sensor unit 191 includes a light projecting / receiving unit 194 including a light projecting unit that generates detection light and a light receiving unit that receives the detection light through the slit 193 of the slit plate 192 and generates the detection signal. And it is attached to the outer edge part of the bearing accommodating part 163 of the casing part 16. That is, the sensor portion 191 is disposed on the bottom portion 145 side of the wheel member 14 and on the outer side in the radial direction from the output bearing 17. The sensor unit 191 is arranged with the optical axis of the detection light directed in the axial direction.

  The slit plate 192 is an identifier that is fixed to the wheel member 14 and arranged in the circumferential direction around the rotation center axis J1. The slit plate 192 is formed of an annular plate member in which a plurality of slits 193 extending radially outward from the inner edge is formed, and is disposed at the outer edge portion of the connecting portion 142 of the wheel member 14.

  The slits 193 are formed by through holes or notches that penetrate the slit plate 192, and are arranged at a constant pitch in the circumferential direction. Further, the slit 193 has a radial length longer than a circumferential width. The light projecting / receiving unit 194 of the sensor unit 191 is disposed to face the inner edge of the slit plate 192 in the axial direction.

  The detection signal output from the sensor unit 191 is used to control the rotation of the wheel member 14. The detection signal detects slippage between the friction members and adjusts the rotation speed of the electric motor 20, or outputs a warning signal for notifying the user of an abnormality by detecting a rotation failure from the increase in slippage. Alternatively, it can be used to output a stop signal for detecting the rotation failure and stopping the electric motor 20. The sensor portion 191 is fixed to the bearing housing portion 163 using a fastening component 6 such as a screw.

  The wiring cable 7 extending from the sensor unit 191 is a transmission line for supplying electric power to the sensor unit 191 and outputting a detection signal from the sensor unit 191, and is used for wiring formed in the cylindrical unit 162 of the casing member 16. Is pulled out of the speed reducer 10 through the groove 164. The groove 164 is formed on the outer peripheral surface of the cylindrical portion 162 and extends substantially in the axial direction and accommodates the wiring cable 7.

  A sensor attachment hole 146 for attaching / detaching the encoder 19 is formed in the bottom portion 145 of the wheel member 14. The sensor attachment hole 146 is a through hole that penetrates the bottom portion 145 and is disposed on the outer edge portion of the connecting portion 142. The sensor portion 191 of the encoder 19 is exposed through the sensor mounting hole 146 of the wheel member 14.

  An assembling method for attaching the sensor portion 191 of the encoder 19 to the casing member 16 is as follows. First, in the first procedure, the input cable 5, the sun roller 11, the planetary roller 12, the carrier is accommodated in a state where the wiring cable 7 is accommodated in the groove 164 and the sensor portion 191 is pulled out from the sensor mounting hole 146 of the wheel member 14. A pin 13, a wheel member 14, an internal ring 15, a casing member 16, an output bearing 17, a wheel bearing 18, a biasing member 153, and a slit plate 192 are disposed.

  Next, in the second procedure, after the sensor portion 191 is accommodated in the sensor mounting hole 146 of the wheel member 14, the sensor portion 191 is slid radially outward along the surface of the slit plate 192. The light projecting / receiving unit 194 of the sensor unit 191 is disposed at the inner edge of the slit plate 192. The sensor unit 191 is fixed to the casing member 16 in this state. In the third procedure, by attaching the wheel cover 4 to the wheel member 14, the sensor attachment hole 146 is sealed, and the speed reduction device 10 is completed.

<Wheel cover 4>
The wheel cover 4 is a disk-shaped member, and has a convex portion protruding toward the electric motor 20 at the center. The wheel cover 4 is attached to the wheel member 14 by inserting the convex portion into a concave portion formed in the bottom portion 145 of the wheel member 14. The concave portion of the bottom portion 145 is formed by disposing the cover plate portion 144 closer to the end face side of the sun roller 11 in the axial direction than the connecting portion 142.

  The wheel cover 4 is fixed to the bottom 145 using a fastening part 3 such as a screw. The fastening component 3 is disposed on the outer edge portion of the wheel cover 4. The sensor mounting hole 146 can be closed by the wheel cover 4 by attaching the wheel cover 4 to the bottom 145 of the wheel member 14.

  FIG. 3 is an explanatory view schematically showing an example of the detailed configuration of the speed reducer 10, in which the friction member, the wheel member 14, the casing member 16, the output bearing 17 and the wheel bearing 18 are shown enlarged. FIG. 3 shows a part of the cut surface when the speed reducer 10 is cut along a plane including the rotation center axis J1.

  The cylindrical portion 162 of the casing member 16 restricts the internal ring 15 from moving outward in the radial direction. For this reason, by accommodating the planetary roller 12 between the cylindrical portion 162 and the sun roller 11, between the internal ring 15 and the small diameter portion 122 of the planetary roller 12, the large diameter portion 121 of the planetary roller 12 and the sun. A constant contact pressure can be ensured with the roller 11.

  If the part where the sun roller 11 and the planetary roller 12 are in contact is referred to as a contact part 8, the wheel bearing 18 overlaps at least a part of the contact part 8 in the axial direction. That is, when viewed from the radial direction, the wheel bearing 18 and the contact portion 8 overlap in the axial direction. Further, the output bearing 17 is disposed on one side in the axial direction with respect to the axial center position of the contact portion 8, that is, on the side opposite to the electric motor 20, whereas the wheel bearing 18 is disposed on the shaft of the contact portion 8. It is arrange | positioned in the other side of an axial direction rather than the center position of a direction, ie, the electric motor 20 side.

  The center-to-center distance A is the distance between the axial center of the output bearing 17 and the axial center of the contact portion 8 and is generally determined by the arrangement of the friction members. On the other hand, the contact pressure between the large-diameter portion 121 of the planetary roller 12 and the sun roller 11 is the contact between the output-side ring 151 of the internal ring 15 and the small-diameter portion 122 of the planetary roller 12 and the input of the internal ring 15. It is desirable to evenly distribute the contact between the side ring 152 and the small diameter portion 122 of the planetary roller 12.

  In order to distribute the load applied to the wheel member 14 to the output bearing 17 and the wheel bearing 18, it is desirable to dispose the output bearing 17 and the wheel bearing 18 as far as possible. The distance B between the axial center of the wheel bearing 18 and the axial center of the contact portion 8 is determined in consideration of these circumstances.

  Each component constituting the reduction gear device 10 according to the present embodiment is as described above. Below, the relationship between these components and the effect produced by it are demonstrated in detail.

(1) Reduction of load applied to friction member In the reduction gear device 10 according to the present embodiment, the wheel member 14 is supported by the casing member 16 via the output bearing 17 and the wheel bearing 18. In particular, the cylindrical portion 143 of the wheel member 14 extends along the outer peripheral surface of the casing member 16 and is supported by the casing member 16 via a wheel bearing 18 disposed between the outer peripheral surface of the casing member 16. Further, since the internal ring 15 that contacts the planetary roller 12 is supported by the casing member 16, the load applied to the wheel member 14 is not directly applied. For this reason, the speed reducer 10 can reduce the load applied to the wheel member 14 from being applied to the friction member.

  Further, in the speed reduction device 10, the output bearing 17 is arranged on one side in the axial direction with respect to the axial center position of the contact part 8, and the wheel bearing 18 is on the other side in the axial direction with respect to the axial center position of the contact part 8. Placed on the side. For this reason, since the load concerning the wheel member 14 is disperse | distributed to the output bearing 17 and the wheel bearing 18, the reduction gear 10 can further reduce that a load is added to a friction member.

(2) Reduction of vibration and noise In the reduction gear device 10 according to the present embodiment, the friction member is constituted by the sun roller 11, the planetary roller 12, and the internal ring 15, and rotates using the frictional force between the peripheral surfaces. Communicated. For this reason, rattling and angular velocity changes due to backlash such as gears are eliminated, and the speed reduction device 10 can reduce vibration and noise when transmitting rotation.

(3) Simplification of Structure In the reduction gear device 10 according to the present embodiment, the cylindrical portion 143 of the wheel member 14 is a wheel that holds the tire 2. For this reason, since the reduction gear 10 has the sun roller 11, the planetary roller 12, and the wheel member 14 as a one-stage reduction mechanism, the number of parts is reduced, and the structure of the reduction gear 10 can be simplified. 10 can be reduced in size.

(4) Reduction in thickness of reduction gear 10 In the reduction gear 10 according to the present embodiment, the position of the wheel bearing 18 and the position of the contact portion 8 overlap in the axial direction. For this reason, the reduction gear 10 can be reduced in thickness because the axial size of the casing member 16 is shortened.

  In the speed reduction device 10, the planetary roller 12 has a large diameter portion 121 and a small diameter portion 122, the large diameter portion 121 is in contact with the outer peripheral surface of the sun roller 11, and the small diameter portion 122 is the inner peripheral surface of the internal ring 15. Contact with. Therefore, the reduction gear device 10 can increase the reduction ratio of the wheel member 14 to the sun roller 11. For this reason, for example, a two-stage reduction ratio can be achieved by a one-stage reduction mechanism, and the reduction gear 10 can be further reduced in thickness. The reduction ratio is a ratio of the rotational speeds of the sun roller 11 and the wheel member 14.

  In the reduction gear device 10, the internal ring 15 faces the large diameter portion 121 of the planetary roller 12 in the axial direction. For this reason, since the size of the planetary roller 12 and the internal ring 15 in the axial direction is shortened, the speed reducer 10 can be further reduced in thickness.

(5) Facilitation of friction force adjustment The speed reduction device 10 according to the present embodiment includes a biasing member 153 that biases the internal ring 15 against the casing member 16 in the axial direction. For this reason, the frictional force between the sun roller 11, the planetary roller 12 and the internal ring 15 can be easily adjusted by the biasing member 153.

(6) Reduction of transmission loss In the reduction gear device 10 according to the present embodiment, the connecting portion 142 of the wheel member 14 connects the carrier pin support portions 141 provided for each planetary roller 12 to each other. For this reason, the speed reducer 10 can directly rotate and drive the wheel that holds the tire 2, and can reduce the transmission loss of rotational energy.

(7) Failure Prevention of Encoder 19 In the reduction gear device 10 according to the present embodiment, the encoder 19 is disposed in a closed space that is blocked from the outside by the wheel member 14, the casing member 16, the output bearing 17, and the wheel bearing 18. For this reason, the speed reducer 10 can prevent the encoder 19 from being damaged due to the influence of dust, water, lubricating oil, and the like.

  In the reduction gear device 10, the encoder 19 is disposed between the wheel member 14 and the casing member 16. For this reason, the speed reducer 10 can suppress the encoder 19 from being affected by the lubricating oil and grease filled in the casing member 16.

(8) Easy attachment / detachment of the encoder 19 In the reduction gear device 10 according to the present embodiment, the sensor mounting hole 146 for exposing the sensor portion 191 of the encoder 19 is formed in the bottom plate portion 145 of the wheel member 14. For this reason, the speed reducer 10 can access the casing member 16 via the sensor mounting hole 146 of the wheel member 14, and can easily attach and detach the sensor unit 191. For example, even when the wheel member 14 is mounted on the casing member 16, the sensor unit 191 can be attached to the casing member 16 or the sensor unit 191 can be detached from the casing member 16.

(9) Simplification of the mounting structure of the encoder 19 In the reduction gear device 10 according to the present embodiment, the sensor portion 191 of the encoder 19 is disposed on the outer side in the radial direction than the output bearing 17. For this reason, the reduction gear device 10 can simplify the structure of the casing member 16 to which the sensor unit 191 is attached.

(10) Increasing the reduction gear ratio of the reduction gear 10 In the reduction gear device 10 according to the present embodiment, the friction member includes the sun roller 11, the planetary roller 12, and the internal ring 15, and uses the friction force between the peripheral surfaces. The rotation is transmitted. For this reason, since the contact area between the sun roller 11 and the planetary roller 12 becomes large, the sun roller 11 can be reduced in diameter and the reduction ratio can be increased.

  For example, a reduction ratio of 1/10 is a limit in a gear transmission type reduction device in which a friction member is composed of a sun gear, a planetary gear, and an internal gear that mesh with each other. On the other hand, the reduction gear 10 can achieve a reduction ratio of 1/20, and can cover the range of the reduction ratio of 1/4 to 1/20.

  In the present embodiment, an example in which the friction member is configured by the sun roller 11, the planetary roller 12, and the internal ring 15 has been described. However, the present invention does not limit the configuration of the friction member. Absent. For example, the present invention can also be applied to a gear transmission type speed reduction device in which a friction member is composed of a sun gear, a planetary gear, and an internal gear that mesh with each other.

  The sun gear is a solar rolling element that rotates about a rotation center axis J1. The planetary gear is a planetary rolling element that is disposed radially outward from the sun gear and to which rotation is transmitted by meshing with the sun gear. The internal gear is an annular rolling member that surrounds two or more planetary gears and meshes with the planetary gears to rotate the planetary gears about the rotation center axis J1.

  In the present embodiment, an example in which a one-stage reduction mechanism is configured by the sun roller 11, the planetary roller 12, and the wheel member 14 has been described. However, the present invention is a reduction apparatus having two or more reduction mechanisms. It can also be applied to.

  In the present embodiment, an example in which the encoder 19 is a transmissive optical rotary encoder has been described. However, the present invention does not limit the configuration of the encoder 19. For example, the encoder 19 may be a reflective optical rotary encoder that receives reflected light from an identifier and generates a detection signal. In the reflective optical rotary encoder, the identifier is configured by arranging a plurality of objects having different reflectances in the circumferential direction. The light receiving unit of the sensor unit receives the detection light emitted from the light projecting unit and reflected by the identifier.

  The encoder 19 may be a magnetic encoder that detects a change in the magnetic field due to the identifier and generates a detection signal. In a magnetic encoder, an identifier is configured by arranging a plurality of magnets in the circumferential direction. The sensor unit is a magnetic sensor that detects a change in the magnetic field, for example, a Hall element.

DESCRIPTION OF SYMBOLS 1 Wheel drive device 10 Deceleration device 11 Sun roller 12 Planetary roller 121 Large diameter part 122 Small diameter part 13 Carrier pin 14 Wheel member 141 Carrier pin support part 142 Connection part 143 Cylindrical part 145 Bottom part 146 Sensor mounting hole 15 Internal ring 151 Output side Ring 152 Input side ring 153 Energizing member 16 Casing member 161 Cover plate portion 162 Cylindrical portion 163 Bearing housing portion 164 Groove 17 Output bearing 18 Wheel bearing 19 Encoder 191 Sensor portion 192 Slit plate 20 Electric motor 30 Electromagnetic brake 2 Tire 4 Wheel cover 5 Input bearing 7 Wiring cable 8 Contact part J1 Rotation center axis J2 Rotation axis

Claims (11)

A solar rolling element that rotates about a rotation center axis;
Two or more planetary rolling elements that are arranged radially outward from the solar rolling element and to which rotation is transmitted by contact with the solar rolling element;
A carrier pin that rotatably supports the planetary rolling element;
A wheel member that rotatably supports the two or more planetary rolling elements and rotates about the rotation center axis;
An annular rolling member that surrounds the two or more planetary rolling elements and rotates the planetary rolling elements about the rotation center axis by contacting the planetary rolling elements;
A casing member that surrounds the solar rolling element and the planetary rolling element and supports the rolling member;
A bearing that rotatably supports the wheel member with respect to the casing member;
The wheel member is
A carrier pin support part for supporting the carrier pin;
A connecting portion extending radially outward from the carrier pin support;
A cylindrical portion extending along an outer peripheral surface of the casing member from an outer edge portion of the connecting portion;
The bearing is
An output bearing disposed between the inner peripheral surface of the casing member and the carrier pin support;
A speed reducer comprising a wheel bearing disposed between an outer peripheral surface of the casing member and an inner peripheral surface of the cylindrical portion. The solar rolling element is a solar roller,
The planetary rolling element is a planetary roller in contact with the outer peripheral surface of the sun roller,
The reduction gear according to claim 1, wherein the rolling member is an internal ring having an inner peripheral surface that contacts an outer peripheral surface of the planetary roller.   The speed reducer according to claim 2, wherein the cylindrical portion of the wheel member is a wheel that holds a tire.   The speed reduction device according to claim 2, wherein the wheel bearing has an axial position overlapping at least a part of a contact portion where the sun roller and the planetary roller are in contact with each other. The output bearing is arranged on one side in the axial direction with respect to the axial center position of the contact portion where the sun roller and the planetary roller are in contact with each other.
The speed reduction device according to any one of claims 2 to 4, wherein the wheel bearing is disposed on the other side in the axial direction with respect to the axial center position of the contact portion. The planetary roller has a large diameter portion and a small diameter portion having different diameters,
The large diameter portion is in contact with the outer peripheral surface of the sun roller,
The speed reducer according to any one of claims 2 to 5, wherein the small diameter portion is in contact with an inner peripheral surface of the internal ring. A biasing member for biasing the internal ring in the axial direction with respect to the casing member;
The reduction gear according to claim 6, wherein the internal ring is opposed to the large-diameter portion of the planetary roller in the axial direction.   The speed reduction device according to any one of claims 1 to 7, wherein the connection portion of the wheel member connects the carrier pin support portions provided for each planetary rolling element to each other. An encoder that detects rotation of the wheel member;
The wheel member has a bottomed cylindrical shape, and a bottom portion is constituted by the carrier pin support portion and the connection portion,
The wheel bearing is disposed on the opening side of the wheel member,
The encoder is
An identifier fixed to the wheel member and arranged in a circumferential direction around the rotation center axis;
The speed reducer according to claim 1, further comprising: a sensor unit that is fixed to the casing member and that generates a detection signal indicating a rotation speed of the wheel member by reading the identifier. . The sensor part of the encoder is disposed on the bottom side of the wheel member,
The speed reduction device according to claim 9, wherein the wheel member has a sensor attachment hole that exposes the sensor portion of the encoder at an outer edge portion of the bottom portion.   The speed reducer according to claim 9, wherein the sensor unit of the encoder is disposed on a radially outer side than the output bearing.

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