JP7380979B2 - Motorized transmission and trolley drive unit - Google Patents

Description

The present invention relates to a motorized transmission and a bogie drive unit having the motorized transmission.

2. Description of the Related Art Conventionally, unmanned transport vehicles have been known that transport objects such as materials in various locations such as factory production lines, hospitals, and offices. The automatic guided vehicle moves the vehicle by rotating the tires by increasing the output torque while decelerating the rotational motion obtained from the electric motor using a speed reducer. A reduction gear used in a conventional automatic guided vehicle is described in, for example, Japanese Patent Application Publication No. 2016-70285.
JP2016-70285A

The speed reduction device disclosed in Japanese Unexamined Patent Publication No. 2016-70285 includes a sun roller, a planetary roller, a carrier pin, a rolling member, a casing member, a wheel member, and a bearing. The sun roller is formed on the shaft of the electric motor. The planetary roller is disposed radially outward of the sun roller, and rotation is transmitted to the planetary roller by contacting the sun roller. The carrier pin rotatably supports the planetary roller. The rolling member rotates the planetary roller and the carrier pin at a reduced rotation speed by surrounding the planetary roller and contacting the planetary roller. The casing member supports the rolling member while surrounding the sun roller and the planetary rollers. The wheel member rotates around the rotation center axis while supporting the carrier pin. The bearing rotatably supports the wheel member relative to the casing member. The tire is held on the outer peripheral surface of the wheel member.

However, in the speed reduction device of the publication, in addition to the dual structure of the wheel member and the casing member, each of which extends in the axial direction on the radially inner side of the tire, there is also a structure for rotatably supporting the wheel member with respect to the casing member. Since bearings are provided, it is necessary to ensure dimensions in the axial direction and radial direction, making miniaturization difficult. Furthermore, there is a possibility that the number of parts will increase and the manufacturing cost of the device will increase. Furthermore, in addition to the tires and wheel members, the planetary rollers revolve around the central axis of rotation and rotate in a complicated manner, so there is a risk that the noise-free characteristics may deteriorate.

An object of the present invention is to provide a structure for a transmission used in an automatic guided vehicle that enables miniaturization, reduces the number of parts to reduce costs, and has excellent silent characteristics.

An exemplary first invention of the present application includes a stationary part, an electric motor having a rotating shaft that rotates about a central axis relative to the stationary part, and a transmission that transmits rotational motion obtained from the electric motor while changing the speed. , the transmission has an outer circumferential surface that extends cylindrically in the axial direction around the central axis, and forms at least a part of the outer circumference of the transmission. a casing, a sun roller fixed around an input part that rotates by power obtained from the electric motor, and rotates together with the input part about the central axis; a plurality of planetary rollers that rotate around an axis of rotation by contacting each other; a carrier that rotatably supports the plurality of planetary rollers via a first bearing; and a radially outer side of at least a portion of the planetary rollers. a ring that extends in an annular shape around the central axis and is indirectly fixed to the casing; each of the plurality of planetary rollers is in contact with the ring; The ring and the casing rotate about the central axis at a rotational speed after the speed change as the plurality of planetary rollers rotate, and the transmission is fixed directly or indirectly to the The first bearing is filled with lubricating oil, and has a through hole that penetrates in the thickness direction on the radially outer side of the central shaft, and into which the lubricating oil enters .
A second exemplary invention of the present application provides an electric motor having a stationary part and a rotating shaft that rotates about a central axis relative to the stationary part, and a transmission that transmits rotational motion obtained from the electric motor while changing the speed. A transmission with an electric motor, wherein the transmission has an outer circumferential surface that extends in a cylindrical shape in the axial direction about the central axis, and a casing that forms at least a part of the outer circumference of the transmission. a sun roller that is fixed around the input section that rotates by power obtained from the electric motor and that rotates together with the input section about the central axis; and a sun roller that is arranged around the sun roller and makes contact with the sun roller. a plurality of planetary rollers that rotate around an axis of rotation; a carrier that rotatably supports the plurality of planetary rollers via a first bearing; a ring that extends in an annular shape around the central axis and is indirectly fixed to the casing; each of the plurality of planetary rollers is in contact with the ring; The ring and the casing rotate about the central axis at a rotational speed after the speed change as the plurality of planetary rollers rotate, and the transmission is fixed directly or indirectly to the The casing is filled with lubricating oil and further includes ribs that protrude radially inward from the inner circumferential surface of the casing, and a plurality of ribs are arranged around the central axis to stir the lubricating oil. Ru.

According to the first exemplary embodiment of the present application, the plurality of planetary rollers are rotatably supported by a carrier fixed to a stationary part of the electric motor. Further, the ring that contacts the plurality of planetary rollers and the casing to which the ring is fixed rotate about the central axis at the speed change speed. Furthermore, the casing forms at least a portion of the outer periphery of the transmission. This makes it possible to reduce the size, reduce the number of parts and reduce costs, and provide a structure with excellent silent characteristics.

FIG. 1 is a longitudinal sectional view of a truck drive unit according to a first embodiment. FIG. 2 is a cross-sectional view of the truck drive unit according to the first embodiment. FIG. 3 is a partial vertical sectional view of the truck drive unit according to the first embodiment. FIG. 4 is a diagram of the planetary roller, carrier, and block bearing according to the first embodiment viewed from the outside in the radial direction. FIG. 5 is a cross-sectional view of the truck drive unit according to the first embodiment. FIG. 6 is a longitudinal cross-sectional view of the truck drive unit according to the second embodiment. FIG. 7 is a partial vertical sectional view of a truck drive unit according to a modification. FIG. 8 is a diagram of a planetary roller, a carrier, and a block bearing according to a modified example, viewed from the outside in the radial direction. FIG. 9 is a longitudinal sectional view of a truck drive unit according to a modification.

Hereinafter, exemplary embodiments of the present application will be described with reference to the drawings. In this application, the direction parallel to the central axis of the reducer is referred to as the "axial direction," the direction perpendicular to the central axis of the reducer is referred to as the "radial direction," and the direction along the arc centered on the central axis of the reducer is referred to as the "axial direction." "circumferential direction". In addition, in this application, in FIGS. 1, 3, 4, 6, 7, 8, and 9, the axial direction is defined as the left-right direction, and the right side is "one axial side" and the left side is "the other axial side. ”, the shape and positional relationship of each part will be explained. However, this definition of the left and right direction is not intended to limit the direction in use of the bogie drive unit according to the present invention. Furthermore, in this application, "parallel directions" include substantially parallel directions. Furthermore, in the present application, "orthogonal directions" include substantially orthogonal directions.

<1. First embodiment>
Below, the configuration of the truck drive unit 1 according to the first embodiment of the present invention will be described. FIG. 1 is a longitudinal cross-sectional view of a truck drive unit 1 according to the first embodiment. FIG. 2 is a cross-sectional view of the truck drive unit 1 when viewed from the AA position in FIG.

The cart drive unit 1 of the present invention is an unmanned transport cart that moves a cart frame 5 on which objects to be transported, such as materials and parts, are placed, in various places such as a factory production line, a hospital, and an office. be. As shown in FIG. 1, the truck drive unit 1 includes a transmission with a motor to which an electric motor 2 and a transmission are connected, tires 4, and a truck frame 5. The truck drive unit 1 transmits rotational motion obtained from the electric motor 2 while changing the speed using a transmission, and rotates the tires 4 to move the truck frame 5. Further, the electric motor 2 has a stationary part including a stator, and a rotating part that rotates around a central axis 20 extending in a horizontal direction (left-right direction in FIG. 1) with respect to the stationary part. The rotating shaft 21, which is a part of the rotating section, passes through the truck frame 5 in the axial direction and is exposed to the outside of the truck frame 5. Note that the transmission of this embodiment is a reduction gear 3 that decelerates the rotational motion obtained from the electric motor 2 to increase output torque. In the following, it is assumed that the central axis 20 of the electric motor 2 and the central axis 9 of the reduction gear 3 coincide with each other.

Next, the detailed configuration of the reduction gear 3 will be explained. As shown in FIGS. 1 and 2, the reducer 3 includes an input section 31, a sun roller 32, a plurality of planetary rollers 33, a carrier 34, a block bearing 35, a casing 36, a support bearing 37, a ring 38, and a first pressing member. 39, a second pressing member 40, and a rib 41.

The input unit 31 is a member that extends in a cylindrical shape in the axial direction centering on the central axis 9 that extends in the horizontal direction (the left-right direction in FIG. 1). The input unit 31 is configured to insert the rotary shaft 21 of the electric motor 2 into the shaft joint 22 located on one side in the axial direction and tighten a screw (not shown), so that the input section 31 receives power in the axial direction via the rotary shaft 21 and the shaft joint 22. Connected. Thereby, the input unit 31 rotates together with the rotating shaft 21 about the central axis 9 at the rotation speed N1 before deceleration by the power obtained from the electric motor 2. In this way, by using the shaft coupling 22 for inserting the rotating shaft, the input section 31 can be connected to various types of electric motors 2. Further, there is no need for a separate joint component, and the axial dimension can be reduced. Note that the rotating shaft 21 and the input section 31 may be formed as an integral structure without using the shaft coupling 22.

The sun roller 32 is a cylindrical member arranged coaxially with the central axis 9. The sun roller 32 is fixed around the input section 31. Therefore, the sun roller 32 rotates together with the input section 31 about the central axis 9 at the rotation speed N1 before deceleration. Note that the input section 31 and the sun roller 32 may be formed from a single member. Further, an oil seal 321 is arranged between the outer circumferential surface of the sun roller 32 near one end in the axial direction and the inner circumferential surface of the carrier 34 in the radial direction. This prevents the lubricating oil filled inside the reducer 3 from leaking to the outside of the reducer 3 through the space near the shaft coupling 22, as described later. Note that the oil seal 321 does not prevent the rotation of the sun roller 32 with respect to the carrier 34.

The plurality of planetary rollers 33 are arranged around the sun roller 32 along respective rotational axes 90 parallel to the central axis 9 . As shown in FIG. 2, in this embodiment, three planetary rollers 33 are arranged at intervals of 120 degrees in the circumferential direction about the central axis 9. However, the number of planetary rollers 33 may be two or four or more. Each of the planetary rollers 33 has a large diameter portion 331, a small diameter portion 332, and a column portion 333. The large diameter portion 331, the small diameter portion 332, and the column portion 333 are formed as one continuous piece. Furthermore, the large diameter portion 331, the small diameter portion 332, and the columnar portion 333 each coaxially expand into a perfect circular shape around the rotation axis 90 when viewed in the axial direction.

The large diameter portion 331 is located at the center of each planetary roller 33 in the axial direction. The outer diameter of the large diameter portion 331 is larger than the outer diameter of the small diameter portion 332 and the outer diameter of the column portion 333. A portion of the large diameter portion 331 is located radially innermost among the planetary rollers 33, contacts the outer circumferential surface of the sun roller 32, and receives frictional force. Here, as will be described in detail later, the carrier 34 holding the three planetary rollers 33 does not rotate about the central axis 9. As a result, the planetary rollers 33 including the large diameter portion 331 rotate about the rotation axis 90 at a rotation speed N2 in a direction opposite to the rotation direction of the sun roller 32 due to the frictional force.

FIG. 3 is a partial vertical sectional view of the truck drive unit 1 according to the first embodiment. As shown in FIG. 3, the small diameter portion 332 includes a first small diameter portion 61 and a second small diameter portion 62. The first small diameter portion 61 is adjacent to the large diameter portion 331 on one side in the axial direction. Further, the first small diameter portion 61 has a truncated conical three-dimensional shape whose diameter decreases toward one side in the axial direction. The second small diameter portion 62 is adjacent to the other axial side of the large diameter portion 331 . Further, the second small diameter portion 62 has a truncated conical three-dimensional shape whose diameter decreases toward the other side in the axial direction. Further, the second small diameter portion 62 has a contact surface 620 that contacts the ring 38 on the outer peripheral surface. However, a contact surface 620 that contacts the ring 38 may be formed on the outer peripheral surface of the first small diameter portion 61.

The column portion 333 includes a first column portion 63 and a second column portion 64. The first column portion 63 is adjacent to one axial side of the first small diameter portion 61 and extends along the rotation axis 90 on one axial side. The second pillar portion 64 is adjacent to the second small diameter portion 62 on the other axial side and extends along the rotation axis 90 on the other axial side.

The carrier 34 is a member that supports the plurality of planetary rollers 33 around the central axis 9 and outside the sun roller 32 in the radial direction. One end of the carrier 34 in the axial direction is directly fixed to the truck frame 5 by screwing, welding, gluing, or the like. A housing including a stationary portion of the electric motor 2 is fixed to the truck frame 5. Thereby, the carrier 34 remains stationary without rotating about the central axis 9. Note that the carrier 34 may be directly fixed to the casing of the electric motor 2 without using the trolley frame 5. Further, the carrier 34 may be indirectly fixed to the truck frame 5 via another member.

FIG. 4 is a diagram of the planetary roller 33, carrier 34, and block bearing 35 according to the first embodiment viewed from the outside in the radial direction. As shown in FIG. 4, the carrier 34 is recessed radially inward from the outer peripheral surface (parallel to the radial direction) at two locations (first position P1, second position P2) that are spaced apart from each other in the axial direction. (extending) slit. The slits include three first slits 341 and three second slits 342. The three first slits 341 are provided at an interval of 120 degrees from each other in the circumferential direction about the central axis 9 at the first position P1 in the axial direction. Further, the three first slits 341 overlap with at least a portion of the first column portions 63 of the three planetary rollers 33, respectively. The three second slits 342 are provided at a distance of 120 degrees from each other in the circumferential direction about the central axis 9 at a second position P2 located on the other axial side of the first position P1. Further, the three second slits 342 overlap with at least a portion of the second column portions 64 of the three planetary rollers 33, respectively.

A block bearing 35 (first block bearing 351) is arranged in each of the three first slits 341. The first block bearing 351 supports the first column portion 63 of the planetary roller 33 so as to be rotatable about the rotation axis 90 . A block bearing 35 (second block bearing 352) is arranged in each of the three second slits 342. The second block bearing 352 supports the second column portion 64 of the planetary roller 33 so as to be rotatable about the rotation axis 90 . For the first block bearing 351 and the second block bearing 352, for example, a sliding bearing having a substantially cubic outer shape is used. When manufacturing the reducer 3, the first block bearing 351 is arranged so as to be movable in the radial direction along the first slit 341. At the same time, the second block bearing 352 is arranged so as to be movable in the radial direction along the second slit 342. Thereby, the three planetary rollers 33 are rotatably supported by the carrier 34 via the block bearings 35, respectively, while being slightly movable in the radial direction. Note that instead of the sliding bearings, other types of bearings such as ball bearings may be used for the first block bearing 351 and the second block bearing 352.

Further, the first block bearing 351 and the second block bearing 352 each have a bearing through hole 350. The bearing through hole 350 penetrates the first block bearing 351 and the second block bearing 352 in the thickness direction on the radially outer side of the central shaft 9. When manufacturing the reducer 3, after assembling each member, the inside of the reducer 3 is filled with lubricating oil. At this time, when lubricating oil is applied from the outer peripheral surface of the planetary roller 33, the lubricating oil enters the bearing through hole 350 and lubricates between the column part 333 of the planetary roller 33 and the block bearing 35 (around the rotating shaft 90). Oil spreads easily. As a result, the planetary roller 33 can more smoothly rotate relative to the carrier 34 via the block bearing 35.

The casing 36 includes the input section 31, the sun roller 32, a plurality of planetary rollers 33, a portion of the carrier 34 excluding the vicinity of one end in the axial direction, a block bearing 35, a support bearing 37, a ring 38, a first pressing member 39, This is a member that accommodates the second pressing member 40 and the rib 41 inside. The casing 36 has an outer circumferential surface that extends cylindrically in the axial direction with the central axis 9 as the center. The casing 36 forms at least a part of the outer circumference of the speed reducer 3. As shown in FIG. 3, the casing 36 includes a cup-shaped first casing 361 and a plate-shaped second casing 362. The first casing 361 is located on one side in the axial direction than the second casing 362. When manufacturing the reducer 3, for example, after each component is assembled inside the first casing 361, the opening on the other axial side of the first casing 361 is covered with the second casing 362. Then, the first casing 361 and the second casing 362 are fixed in the axial direction using screws 363. Thereby, the entire reduction gear 3 can be easily assembled. However, the configuration of the casing 36 is not limited to this.

As shown in FIG. 1, two support bearings 37 are arranged on the inner peripheral surface of the casing 36 and are spaced apart from each other in the axial direction. The support bearing 37 includes a first support bearing 371 and a second support bearing 372. The first support bearing 371 is located on one side in the axial direction than the second support bearing 372. Further, the first support bearing 371 and the second support bearing 372 have the same structure. As shown in FIG. 3, the support bearing 37 includes an inner ring 91, a plurality of balls 92, and an outer ring 93. The inner ring 91 is fixed to the outer peripheral surface of the carrier 34. The plurality of balls 92 are interposed between the inner ring 91 and the outer ring 93. The outer ring 93 is fixed to the inner peripheral surface of the casing 36. Thereby, the casing 36 is rotatably supported by the carrier 34 via the support bearing 37 about the central axis 9 . In this way, a ball bearing is used for the support bearing 37. However, instead of ball bearings, other types of bearings such as roller bearings may be used. Further, the number of support bearings 37 is not limited to two.

FIG. 5 is a cross-sectional view of the truck drive unit 1 when viewed from the BB position in FIG. As shown in FIGS. 1, 3, and 5, the ring 38 expands in an annular shape around the central axis 9 on the radially outer side of at least a portion of the second small diameter portion 62 of the planetary roller 33. As shown in FIGS. A ring through hole 380 is provided at at least one location in the circumferential direction of the ring 38 . The ring through hole 380 is a through hole that passes through the ring 38 in the axial direction. A fixing pin 368 extending in the axial direction from the second casing 362 is inserted into the ring through hole 380 . This prevents the ring 38 from rotating relative to the second casing 362 in the circumferential direction. That is, the ring 38 is indirectly fixed to the second casing 362 in the circumferential direction using the fixing pin 368. Note that the ring 38 is slightly movable in the axial direction along the fixed pin 368.

The inner peripheral surface of the ring 38 contacts the contact surface 620 of the second small diameter portion 62 of the planetary roller 33 and receives a frictional force. Thereby, the ring 38 and the casing 36 rotate about the central axis 9 due to the frictional force. Here, as described above, the three planetary rollers 33 each rotate around the rotation axis 90 at the rotation speed N2 in a direction opposite to the rotation direction of the sun roller 32. Therefore, as the three planetary rollers 33 rotate, the ring 38 and the casing 36 rotate in the same direction as the rotational direction of the three planetary rollers 33, that is, in the opposite direction to the rotational direction of the sun roller 32. It rotates by the number N3.

The first pressing member 39 is an elastic body that extends along the central axis 9 on the other axial side of at least a portion of the circumferential direction of the ring 38 . For the first pressing member 39, a coil spring, a leaf spring, rubber, or the like is used, for example. The other axial end of the first pressing member 39 is directly fixed to the second casing 362 . However, the other axial end of the first pressing member 39 may be indirectly fixed to the second casing 362 via another member. Further, one end of the first pressing member 39 in the axial direction contacts the ring 38 . Therefore, a biasing force directed toward one side in the axial direction is applied to the ring 38 from the first pressing member 39 . Here, as described above, the second small diameter portion 62 of the planetary roller 33 that comes into contact with the ring 38 is a truncated cone-shaped solid whose diameter decreases toward the other side in the axial direction (the diameter expands toward the one side in the axial direction). It has a shape. Therefore, the ring 38 comes into more secure contact with the contact surface 620 of the second small diameter portion 62, and the planetary roller 33 is pressed radially inward by the urging force received from the ring 38. As a result, the planetary roller 33 firmly contacts the sun roller 32.

However, the configurations of the ring 38 and the first pressing member 39 are not limited to this. For example, the ring 38 may be arranged radially outward of at least a portion of the first small diameter portion 61 of the planetary roller 33 so as to expand in an annular shape around the central axis 9. The first pressing member 39 may be arranged to extend along the central axis 9 on one axial side of at least a portion of the circumferential direction of the ring 38 . One end of the first pressing member 39 in the axial direction is directly or indirectly fixed to the first casing 361, and the other end of the first pressing member 39 in the axial direction contacts the ring 38. You may. Even in such a configuration, the first pressing member 39 applies a biasing force toward the other side in the axial direction to the ring 38, so that the ring 38 more firmly contacts the contact surface of the first small diameter portion 61, and the planetary roller 33 can be brought into firm contact with the sun roller 32.

The second pressing member 40 is located on one axial side of the large diameter portion 331 of the planetary roller 33 and radially outward of at least a portion of the first small diameter portion 61 . The second pressing member 40 has a fixed ring 401, a movable ring 402, and a sphere 403. The fixed ring 401 and the movable ring 402 each extend in an annular shape around the central axis 9. Furthermore, the fixed ring 401 is located on one side of the movable ring 402 in the axial direction. Fixing ring 401 is fixed to first casing 361. The movable ring 402 is indirectly fixed to the first casing 361 via the fixed ring 401.

The second pressing member 40 is constituted by a pressure regulating cam that converts rotational torque about the central shaft 9 into force directed toward the other side in the axial direction. Specifically, when the second pressing member 40 receives rotational torque about the central axis 9, the sphere 403 rides on a plurality of inclined surfaces provided in the circumferential direction of the fixed ring 401 and the movable ring 402. As a result, the movable ring 402 is pressed toward the other side in the axial direction with respect to the fixed ring 401. Here, with the fixed ring 401 fixed to the first casing 361, the inner peripheral surface of the movable ring 402 contacts the first small diameter portion 61. By pressing the movable ring 402 to the other side in the axial direction in this way, the movable ring 402 contacts the contact surface of the first small diameter portion 61 more firmly, and the second pressing member 40 contacts the first small diameter portion 61. A biasing force directed toward the other side in the axial direction is applied in proportion to the rotational torque.

Here, as described above, the first small diameter portion 61 of the planetary roller 33 that comes into contact with the movable ring 402 has a truncated conical shape that decreases in diameter toward one side in the axial direction (increases in diameter toward the other side in the axial direction). It has a three-dimensional shape. Therefore, the planetary roller 33 is pressed radially inward by the urging force received from the movable ring 402. As a result, the planetary roller 33 firmly contacts the sun roller 32. However, the configuration of the second pressing member 40 is not limited to this. For example, the second pressing member 40 is arranged in an annular shape around the central axis 9 on the other axial side of the large diameter portion 331 of the planetary roller 33 and on the radial outer side of at least a portion of the second small diameter portion 62. They may be arranged so as to spread out. The inner peripheral surface of the movable ring 402 may contact the second small diameter portion 62 of the planetary roller 33. Furthermore, the speed reducer 3 may have a plurality of first pressing members 39 or a plurality of second pressing members 40. Further, the speed reducer 3 may include only one of the first pressing member 39 and the second pressing member 40.

As shown in FIGS. 2 and 5, the ribs 41 protrude radially inward from the inner peripheral surface of the casing 36. As shown in FIGS. When the trolley drive unit 1 is in use, the rib 41 rotates about the central axis 9 together with the casing 36 and the ring 38 . As a result, the lubricating oil filled inside the reducer 3 is agitated and easily spreads inside the casing 36. Note that in this embodiment, eight ribs 41 are provided. However, the number of ribs 41 may be seven or less, or nine or more.

As described above, when the trolley drive unit 1 is used, the input section 31 and the sun roller 32 first rotate about the central axis 9 at the rotation speed N1. Then, each of the three planetary rollers 33 rotates about the rotation axis 90 at a rotation speed N2 due to the frictional force between the large diameter portion 331 and the sun roller 32. The rotational speed N2 of the planetary roller 33 is determined by "N2=N1×D1/D2" using "outer diameter D1 of the sun roller 32" and "outer diameter D2 of the large diameter portion 331 of the planetary roller 33". Calculated using the formula.

When the three planetary rollers 33 rotate, the ring 38 and the casing 36 rotate around the central axis 9 at a rotation speed N3 due to the frictional force between the ring 38 and the second small diameter portion 62 of the three planetary rollers 33. do. The rotation speed N3 of the ring 38 and the casing 36 is calculated using the formula "N3 = N2 x D3/D4" using the "outer diameter D3 of the second small diameter portion 62" and the "inner diameter D4 of the ring 38". be done. Furthermore, from the above, the reduction ratio "N3/N1" of the speed reducer 3 is calculated using the formula "N3/N1=(D1×D3)/(D2×D4)." Here, as described above, the planetary roller 33 has the large diameter portion 331 and the second small diameter portion 62. In this embodiment, "the outer diameter D3 of the second small diameter section 62" is smaller than the "outer diameter D2 of the large diameter section 331." As a result, the reduction ratio "N3/N1" of the reduction gear 3 becomes smaller, so that the rotational motion can be further decelerated and a higher output torque can be obtained.

Furthermore, the tire 4 is directly fixed to the outer peripheral surface of the casing 36. When the trolley drive unit 1 is used, the tire 4 together with the casing 36 rotates about the central shaft 9 at a rotational speed N3 after shifting. As a result, the truck frame 5 moves in the horizontal direction (the front or depth direction in FIG. 1). Note that the tire 4 may be indirectly fixed to the outer peripheral surface of the casing 36 via another member.

As described above, the bogie drive unit 1 of the present embodiment has a configuration in which the tires 4 are fixed to the outer peripheral surface of the casing 36 itself, which rotates around the central axis 9 as the planetary rollers 33 rotate (rotate). For this reason, compared to the conventional structure which has a wheel member that holds the tire in addition to the carrier pin that holds the planetary roller and rotates with the rotation of the planetary roller, the entire bogie drive unit 1 is moved in the axial direction. and can be downsized in the radial direction. Moreover, the number of parts can be suppressed and the manufacturing cost of the truck drive unit 1 can be reduced. Furthermore, in the truck drive unit 1 of this embodiment, the three planetary rollers 33 only rotate around the rotation axis 90 and do not rotate (revolution) around the central axis 9. Therefore, since the number of rotating elements in the truck drive unit 1 is limited, the quietness characteristics can be improved. As a result, the trolley drive unit 1 can be utilized even in places such as hospitals or offices where higher quietness characteristics are required.

<2. Second embodiment>
Next, a second embodiment of the present invention will be described. FIG. 6 is a longitudinal cross-sectional view of a truck drive unit 1B according to the second embodiment. Note that the following description will focus on the differences from the first embodiment, and redundant description of portions that are equivalent to the first embodiment will be omitted.

As shown in FIG. 6, the truck drive unit 1B includes a transmission with an electric motor to which an electric motor 2B and a reduction gear 3B are connected, tires 4B, a truck frame 5B, and wheels 7B. The reducer 3B includes an input section 31B, a sun roller 32B, a plurality of planetary rollers 33B, a carrier 34B, a block bearing 35B, a casing 36B, a support bearing 37B, a ring 38B, a first pressing member 39B, a second pressing member 40B, and ribs. has. The sun roller 32B, the plurality of planetary rollers 33B, the carrier 34B, the block bearing 35B, the casing 36B, the support bearing 37B, the ring 38B, the first pressing member 39B, the second pressing member 40B, and the ribs are the same as the sun of the first embodiment. Since it has the same configuration as the roller 32, the plurality of planetary rollers 33, the carrier 34, the block bearing 35, the casing 36, the support bearing 37, the ring 38, the first pressing member 39, the second pressing member 40, and the rib 41, there is no overlap. The explanation will be omitted.

The input section 31B is a member that extends in a cylindrical shape in the axial direction centering on the central axis 9B. The input section 31B of this embodiment is rotatably supported by the carrier 34B via a support bearing 311B. For example, a ball bearing is used for the support bearing 311B. However, instead of ball bearings, other types of bearings such as roller bearings and sliding bearings may be used.

The wheel 7B has a tire support part 71B and a connection part 72B. The tire support portion 71B has an outer circumferential surface that extends cylindrically in the axial direction around the central axis 9B on the radially outer side of the casing 36B. Casing 36B and ring 38B are arranged radially inside tire support section 71B. The tire 4B is fixed to the outer peripheral surface of the tire support portion 71B. The connecting portion 72B is a portion that extends radially inward from the other axial end of the tire support portion 71B. A portion of the connecting portion 72B including the radially inner end portion is connected to the casing 36B by screwing or the like. Note that the wheel 7B and the casing 36B may be formed from a single member. Thereby, the number of parts of the truck drive unit 1B can be suppressed, and manufacturing costs can be reduced.

When the trolley drive unit 1B is used, the casing 36B, the wheels 7B and the tires 4B rotate about the central axis 9B. As a result, the truck frame 5B moves in the horizontal direction (the front or depth direction in FIG. 6). By providing the wheels 7B in this manner, the diameter of the tires 4B can be freely selected depending on the location or method of use of the bogie drive unit 1B.

<3. Modified example>
Although exemplary embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments.

FIG. 7 is a partial vertical cross-sectional view of a truck drive unit 1C according to a modified example. In the example of FIG. 7, the planetary rollers 33C each have a large diameter portion 331C, a small diameter portion 332C, and a column portion 333C. The small diameter portion 332C includes a first small diameter portion 61C and a second small diameter portion 62C. Further, the first small diameter portion 61C has a truncated conical three-dimensional shape whose diameter decreases toward one side in the axial direction. Further, the outer diameter of the other axial end of the first small diameter portion 61C is approximately the same as the outer diameter of the one axial end of the large diameter portion 331C. The second small diameter portion 62C has a truncated conical three-dimensional shape whose diameter decreases toward the other side in the axial direction. Further, the outer diameter of the second small diameter portion 62C at one end in the axial direction is approximately the same as the outer diameter of the other end of the large diameter portion 331C in the axial direction. Here, similarly to the first embodiment, the reduction ratio of the speed reducer 3C is calculated using "the outer diameter D2 of the large diameter section 331C" and "the outer diameter D3 of the second small diameter section 62C". As in this modification, various speed reduction ratios can be obtained by changing the ratio between "the outer diameter D2 of the large diameter section 331C" and "the outer diameter D3 of the second small diameter section 62C."

FIG. 8 is a diagram of a planetary roller 33D, a carrier 34D, and a block bearing 35D according to another modification as viewed from the outside in the radial direction. In the example of FIG. 8, the block bearing 35D includes a first block bearing 351D and a second block bearing 352D. The first block bearing 351D is located on one side in the axial direction than the second block bearing 352D. Moreover, the first block bearing 351D and the second block bearing 352D have a bearing through-slit 350D. The bearing penetration slit 350D is a slit-shaped through hole that penetrates the first block bearing 351D and the second block bearing 352D in the thickness direction over the entire axial direction. When lubricating oil is applied from the outer peripheral surface of the planetary roller 33D during manufacturing of the reducer, the lubricating oil enters the bearing penetration slit 350D, and the lubricating oil is spread between the planetary roller 33D and the block bearing 35D (around the rotation axis 90D). becomes easier to spread. As a result, the planetary roller 33D can more smoothly rotate relative to the carrier 34D via the block bearing 35D.

FIG. 9 is a longitudinal cross-sectional view of a truck drive unit 1E according to another modification. In the example of FIG. 9, one end of the carrier 34E in the axial direction is fixed to the casing of the electric motor 2E with a screw 82E via a mounting plate 81E. The other end of the carrier 34E in the axial direction is fixed to the truck frame 5E using a screw 83E. Furthermore, the truck frame 5E of this modification covers a portion of the other axial side and the upper side of the reducer 3E including the tires 4E. Therefore, it is possible to suppress objects to be transported such as materials and parts placed on the truck frame 5E, or workers from coming into contact with the speed reducer 3E including the tires 4E.

Further, the detailed shape of the bogie drive unit including the motorized transmission may be different from the shape shown in each figure of the present application. Furthermore, the elements appearing in the above-described embodiments and modifications may be combined as appropriate to the extent that no contradiction occurs.

INDUSTRIAL APPLICATION This invention can be utilized for the transmission with an electric motor, and the trolley|bogie drive unit which has a transmission with an electric motor.

1, 1B, 1C, 1E Bogie drive unit 2, 2B, 2E Electric motor 3, 3B, 3C, 3E Reducer 4, 4B, 4E Tire 5, 5B, 5E Bogie frame 7B Wheel 9, 9B Center shaft 20 Center shaft 21 Rotation Shaft 22 Shaft coupling 31, 31B Input section 32, 32B Sun roller 33, 33B, 33C, 33D Planetary roller 34, 34B, 34D, 34E Carrier 35, 35B, 35D Block bearing 36, 36B, 36D Casing 37, 37B Support bearing 38 , 38B Ring 39, 39B First pressing member 40, 40B Second pressing member 41 Rib 61, 61C First small diameter part 62, 62C Second small diameter part 63 First pillar part 64 Second pillar part 90, 90D Rotation shaft 331, 331C Large diameter section 332, 332C Small diameter section 333, 333C Column section 341 First slit 342 Second slit 351, 351D First block bearing 352, 352D Second block bearing 350 Bearing through hole 350D Bearing through slit 368 Fixing pin 401 Fixing ring 402 Movable ring 403 Sphere 620 Contact surface

Claims (15)

an electric motor having a stationary part and a rotating shaft that rotates about a central axis with respect to the stationary part;
a transmission that transmits the rotational motion obtained from the electric motor while changing the speed;
A transmission with an electric motor,
The transmission is
a casing having an outer circumferential surface extending in a cylindrical shape in the axial direction about the central axis, and forming at least a part of the outer circumference of the transmission;
a sun roller fixed around an input section that rotates by power obtained from the electric motor, and that rotates together with the input section about the central axis;
a plurality of planetary rollers that are arranged around the sun roller and rotate about their rotational axis by respectively contacting the sun roller;
a carrier that rotatably supports the plurality of planetary rollers via a first bearing;
a ring that extends in an annular shape around the central axis at a radially outer side of at least a portion of the planetary roller and is indirectly fixed to the casing;
has
Each of the plurality of planetary rollers is in contact with the ring,
The carrier is directly or indirectly fixed to the stationary part of the electric motor,
The ring and the casing rotate about the central axis at a rotation speed after the speed change as the plurality of planetary rollers rotate,
The transmission is filled with lubricating oil,
The first bearing is a transmission with an electric motor, and the first bearing is a through hole that penetrates in the thickness direction on the outside in the radial direction of the central shaft, and has a bearing through hole through which the lubricating oil enters . The electric motorized transmission according to claim 1,
A transmission with an electric motor, further comprising a rib protruding radially inward from an inner circumferential surface of the casing. an electric motor having a stationary part and a rotating shaft that rotates about a central axis with respect to the stationary part;
a transmission that transmits the rotational motion obtained from the electric motor while changing the speed;
A transmission with an electric motor,
The transmission is
a casing having an outer circumferential surface extending in a cylindrical shape in the axial direction about the central axis, and forming at least a part of the outer circumference of the transmission;
a sun roller fixed around an input section that rotates by power obtained from the electric motor, and that rotates together with the input section about the central axis;
a plurality of planetary rollers that are arranged around the sun roller and rotate about their rotational axis by respectively contacting the sun roller;
a carrier that rotatably supports the plurality of planetary rollers via a first bearing;
a ring that extends in an annular shape around the central axis at a radially outer side of at least a portion of the planetary roller and is indirectly fixed to the casing;
has
Each of the plurality of planetary rollers is in contact with the ring,
The carrier is directly or indirectly fixed to the stationary part of the electric motor,
The ring and the casing rotate about the central axis at a rotation speed after the speed change as the plurality of planetary rollers rotate,
The transmission is filled with lubricating oil,
further comprising a rib protruding radially inward from the inner circumferential surface of the casing,
A transmission with an electric motor, wherein a plurality of ribs are arranged around the central axis and stir the lubricating oil . A transmission with an electric motor according to any one of claims 1 to 3,
The rotation axis is arranged parallel to the central axis,
Each of the plurality of planetary rollers has a large diameter portion that contacts the sun roller;
a small diameter portion having a contact surface that contacts the ring on one axial side of the large diameter portion;
has
The small diameter portion has a truncated conical shape whose diameter decreases toward one side in the axial direction,
The transmission is
A transmission with an electric motor, further comprising a pressing member that applies a force toward the other side in the axial direction to the ring to bring the ring into contact with the contact surface. The electric motor-equipped transmission according to any one of claims 1 to 4,
The carrier has a slit extending in the radial direction,
A transmission with an electric motor, wherein the first bearing is movable in a radial direction along the slit. The electric motorized transmission according to claim 4,
The pressing member is an elastic body having one axial end fixed directly or indirectly to the casing and the other axial end contacting the ring. The electric motorized transmission according to claim 4,
The pressing member is constituted by a pressure regulating cam that extends in an annular shape around the central axis on one axial side of the ring and converts rotational torque around the central axis into force directed toward the other axial side. Transmission with electric motor. The electric motor-equipped transmission according to any one of claims 1 to 7,
The ring is fixed to an inner circumferential surface of the casing. A transmission with an electric motor according to any one of claims 1 to 8,
The input section is a transmission with an electric motor, and the input section is axially connected to a rotating shaft of the electric motor via a shaft coupling. The electric motorized transmission according to claim 9,
The input section is a transmission with an electric motor, and the input section is connected in the axial direction via the shaft coupling into which the rotating shaft is inserted, which is located on one side of the input section in the axial direction. The electric motorized transmission according to claim 4,
The large diameter portion has a cylindrical shape extending around the rotation axis,
An electric motor-equipped transmission, wherein an outer diameter of the other end of the small diameter portion in the axial direction is substantially the same as an outer diameter of the end of the large diameter portion on the one side in the axial direction. A truck drive unit that drives a truck frame,
A transmission with an electric motor according to any one of claims 1 to 11,
a tire that is directly or indirectly fixed to the outer peripheral surface of the casing, at least a portion of which is located below the truck frame, and rotates together with the casing about the central axis;
has
A truck drive unit, wherein the truck frame is directly or indirectly fixed to the carrier. The truck drive unit according to claim 12,
further comprising a wheel connected to the casing and having an outer circumferential surface extending cylindrically in the axial direction around the central axis on the radially outer side of the casing;
The tire is a bogie drive unit fixed to the outer peripheral surface of the wheel. The truck drive unit according to claim 13,
The ring is a bogie drive unit arranged radially inside the wheel. The truck drive unit according to claim 13 or 14,
A truck drive unit, wherein the wheel and the casing are formed from a single piece.

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