Reducer, vehicle, and electric vehicle

Abstract

To provide a friction transmission type reducer which has high torque transmission efficiency, suppresses vibration and noise, and realizes deceleration with a high reduction ratio. [Solution] The reducer comprises a case, a sun roller having a rotating shaft coincident with a central axis and rotating around the axis of the rotating shaft relative to the case when rotation is input, a number of intermediate rollers having an outer circumferential surface pressed against the outer circumferential surface of the sun roller and rotating in response to the rotation of the sun roller, a moving mechanism provided in the case, supporting each of the intermediate rollers and moving the intermediate rollers radially relative to the sun roller relative to the central axis of the sun roller, a number of outer rollers having an outer circumferential surface pressed against the outer circumferential surfaces of the multiple intermediate rollers and rotating in response to the rotation of the intermediate rollers, and an outer ring having an inner circumferential surface pressed against the outer circumferential surface of the outer rollers and rotating in response to the rotation of the outer rollers.

Description

[Technical field]

[0001] The present invention relates to a reducer, a vehicle, and an electric vehicle. [Background technology]

[0002] In recent years, motors for electric vehicles (EVs) have become faster, with the target speed being as high as 50,000 revolutions per minute. In such cases, the reducer (drive system) combined with the motor is required to handle the high input revolutions, such as by having a higher reduction ratio than before.

[0003] Friction transmission type reducers are seen as one promising way to deal with such high input rotation speeds. In friction transmission type reducers, there is no change in gear meshing, so there is little torque fluctuation or noise caused by tooth strike. In addition, there is no problem with poor lubrication of the gear base at high rotation speeds, so it is considered to be advantageous for high rotation speeds.

[0004] For example, Patent Document 1 discloses such a friction transmission type continuously variable transmission for a vehicle. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2012-167810 A [Patent Document 2] Special Publication No. 60-5819 [Patent Document 3] Special Publication No. 60-24341 [Patent Document 4] JP 2008-215478 A Summary of the Invention [Problem to be solved by the invention]

[0006] There is a demand for a friction transmission type reducer that can use a high rotation speed motor, has high torque transmission efficiency, suppresses vibration and noise, and achieves a high reduction ratio.

[0007] An object of the present invention is to provide a friction transmission type reducer that has high torque transmission efficiency, suppresses vibration and noise, and achieves a high reduction ratio. [Means for solving the problem]

[0008] A reducer according to one aspect of the present invention includes a case, a sun roller having a rotation axis coinciding with a central axis and rotating about the rotation axis relative to the case when rotation is input, a number of intermediate rollers having an outer circumferential surface pressed against the outer circumferential surface of the sun roller and rotating in response to the rotation of the sun roller, and a movement mechanism provided in the case, supporting each of the intermediate rollers and moving the intermediate rollers relative to the sun roller in a radial direction relative to the central axis of the sun roller. a first roller having an outer circumferential surface pressed against the outer circumferential surface of the intermediate roller and rotating in response to the rotation of the intermediate roller, and a second roller spaced apart in the circumferential direction from the first roller, having an outer circumferential surface pressed against the outer circumferential surface of the same intermediate roller as the intermediate roller against which the outer circumferential surface of the first roller is pressed, and rotating in response to the rotation of the intermediate roller, Multiple outer rollers Department and, a first coupler that connects a rotation shaft of the first roller and a rotation shaft of the second roller of one of the outer roller units, rotates the first roller and the second roller in the same direction in response to the rotation of the intermediate roller, and abuts against or separates from the case; and a second coupler that connects a rotation shaft of the first roller and a rotation shaft of the second roller of another of the outer roller units, rotates the first roller and the second roller in the same direction in response to the rotation of the intermediate roller, and abuts against or separates from the case, and is spaced apart in the circumferential direction from the first coupler; The outer roller Department of The outer circumferential surface of the first roller and the outer circumferential surface of the second roller are connected by the first coupler. Outer surface The outer circumferential surface of the first roller and the outer circumferential surface of the second roller connected by the second coupler the inner peripheral surface being pressed against the outer roller The first roller and the second roller of the and an outer ring which rotates in response to the rotation of the rotor. Effect of the Invention

[0009] According to the present invention, (1) A high pressing load is generated between the friction surfaces when a rotational torque is transmitted from a motor. (2) making the pressing load proportional to the torque when the rotational torque is transmitted from the motor; (3) No speed difference is generated on the friction contact surface when the rotational torque is transmitted from the motor. (4) The case is not subjected to the pressing force of the friction surface when the rotational torque is transmitted from the motor. It is possible to provide a friction transmission type reducer which satisfies the above requirements, has high torque transmission efficiency, suppresses vibration and noise, and achieves a high reduction ratio. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram of an electric vehicle. [Diagram 2] FIG. 2 is a schematic front view of the roller type reducer according to the first embodiment. [Diagram 3] FIG. 3 is a schematic exploded perspective view of the reducer shown in FIG. [Figure 4] FIG. 4 is a schematic diagram showing the operation of the reducer when torque is transmitted to the sun roller of the reducer shown in FIGS. [Diagram 5] FIG. 5 is a schematic exploded perspective view of a roller type reducer according to the second embodiment. [Figure 6] FIG. 6 is a diagram showing the relationship between the case and the intermediate roller support portion shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] An electric vehicle 10 according to an embodiment will be described with reference to FIGS.

[0012] FIG. 1 shows a schematic diagram of a vehicle 10a of an electric vehicle 10 (vehicle for an electric vehicle) according to an embodiment.

[0013] As shown in Fig. 1, a vehicle 10a of an electric vehicle 10 includes a battery 12, an inverter 14, a motor 16, and a reducer (a reducer for an electric vehicle) 18. The battery 12 is used as a DC power source. The inverter 14 converts the DC power from the battery 12 into AC power to drive the motor 16, which is driven by AC power. A reducer 18 that can be set to an appropriate reduction ratio is connected to a drive shaft of the motor 16. Then, the power reduced to a predetermined reduction ratio by the reducer 18 is transmitted to wheels 22 via a drive shaft 20.

[0014] The vehicle 10a may be rear-wheel drive, front-wheel drive, or two-wheel drive.

[0015] 1, the drive shaft 20 is used to transmit power reduced by the reduction gear 18 to the wheels 22. The vehicle 10a of the electric vehicle 10 may employ a so-called in-wheel motor system in which the motor 16 and the reduction gear 18 are disposed on each wheel 22 and the wheels are driven directly by the reduction gear 18.

[0016] (First embodiment) The reducer (roller type reducer) 18 according to the first embodiment will be described with reference to FIGS. 2 to 4. FIG.

[0017] Fig. 2 is a schematic front view of the reducer 18 according to the present embodiment. Fig. 3 is a schematic exploded perspective view of the reducer 18 according to the present embodiment.

[0018] As shown in Figures 2 and 3, the reducer 18 includes a case (base) 30, a sun roller 32, multiple intermediate rollers 34, multiple outer rollers 36, multiple outer roller couplers 38, an outer ring 40, multiple swing arm support pins (support pins) 42, and a swing arm 44 as a moving mechanism that moves the intermediate rollers 34 radially relative to the central axis of the sun roller 32.

[0019] The case 30 is formed as an exterior of the reducer 18. Only a portion of the case 30 is shown in Fig. 2 and Fig. 3. For ease of explanation, a portion of the case 30 is formed, for example, in a flat plate shape. In this embodiment, at least a portion of the exterior of the case 30 is formed in a disk shape or a substantially disk shape. Note that the case 30 may be hollowed out, for example, to reduce weight.

[0020] The sun roller 32, the multiple intermediate rollers 34 and the multiple outer rollers 36 are preferably arranged with their central axes (rotation axes) parallel to one another, and are each formed as an approximately cylindrical roller to ensure a sufficient contact area and contact length with each other.

[0021] Rotation (driving force) is input to the sun roller 32 from the motor 16, which is driven by power supplied from the battery 12. The sun roller 32 is supported by bearings (not shown) so as to be rotatable about a predetermined rotation axis that coincides with the central axis of the case 30. Therefore, when rotation is input, the sun roller 32 rotates about the rotation axis relative to the case 30.

[0022] The case 30 is provided with a swing arm support pin 42 that rotatably supports the intermediate roller 34. The swing arm support pin 42 is, for example, fixed and integrated with the case 30. The swing arm support pin 42 is formed in a cylindrical or columnar shape. The swing arm support pin 42 is preferably arranged at a position equidistant from the central axis of the sun roller 32 in the case 30, with the central axis of the swing arm support pin 42 being arranged on a virtual axis parallel to the central axis of the sun roller 32 that passes through the apex of an equilateral triangle. The arrangement of the swing arm support pin 42 may be shifted from the apex of the equilateral triangle in order to reduce noise generated by the reducer 18. In this embodiment, three swing arm support pins 42 are provided on one surface of the flat plate portion of the case 30. The three swing arm support pins 42 are formed to have the same size and shape, for example, in a columnar shape.

[0023] In addition, the rotation axis of the case 30 at the position where the central axis of the sun roller 32 is supported is defined as the central axis of the reducer 18. In other words, the central axis of the sun roller 32 is defined as the central axis of the reducer 18.

[0024] The number of swing arm support pins 42 is preferably four if the number of intermediate rollers 34 is four. If there are four or more swing arm support pins 42, it is preferable that the central axes of the swing arm support pins 42 are disposed on an imaginary axis that is equidistant from the central axis of the sun roller 32 (the central axis of the reducer 18) in the case 30 and is parallel to the central axis of the sun roller 32 that passes through the vertices of a regular polygon. Note that such an arrangement of the swing arm support pins 42 may be shifted from the vertices of the regular polygon to reduce noise generated by the reducer 18.

[0025] A swing arm 44 is supported by the swing arm support pin 42 via a bearing (not shown) so as to be rotatable about an axis whose rotation axis is the central axis of the swing arm support pin 42 .

[0026] The swing arm 44 is provided in a swingable manner on the case 30, and allows radial movement with respect to the central axis of the sun roller 32 and the outer roller 36. The swing arm 44 includes a cylindrical portion 44a through which the swing arm support pin 42 is inserted, a plate 44b on which the cylindrical portion 44a is supported, and an intermediate roller support pin 44c supported by the plate 44b. The central axis of the cylindrical portion 44a and the central axis of the intermediate roller support pin 44c are arranged in parallel. When the swing arm support pin 42 is inserted into the cylindrical portion 44a of the swing arm 44, the central axis of the swing arm support pin 42 and the central axis of the cylindrical portion 44a coincide with each other, and the central axis of the intermediate roller support pin 44c is arranged in parallel with the central axis of the swing arm support pin 42 and the central axis of the cylindrical portion 44a.

[0027] The intermediate roller 34 is supported by the intermediate roller support pin 44c via a bearing (not shown) so as to be rotatable about its axis. At this time, the central axis of the intermediate roller 34 coincides with the central axis of the intermediate roller support pin 44c.

[0028] The three sets of intermediate rollers 34, swing arm support pins 42, and swing arms 44 according to this embodiment are positioned such that the swing arm support pins 42, plates 44b of the swing arms 44, and intermediate rollers 34 are arranged clockwise with respect to the central axis of the sun roller 32. It is preferable that the direction in which the plate 44b of the swing arm 44 extends is perpendicular to the radial direction with respect to the central axis of the sun roller 32. It is also preferable that the direction in which the plate 44b of the swing arm 44 extends is appropriately shifted from the direction perpendicular to the radial direction with respect to the central axis of the sun roller 32.

[0029] The reducer 18 according to this embodiment has six outer rollers 36. In this embodiment, the multiple outer rollers 36 are formed in three pairs. That is, the reducer 18 has three outer roller portions 37, with two outer rollers 36 forming one pair. The outer peripheral surfaces of the two outer rollers 36 of one outer roller portion 37 each come into contact with the outer peripheral surface of one intermediate roller 34.

[0030] For this reason, each outer roller portion 37 includes a first roller (outer roller) 36 that is pressed against the outer peripheral surface of the intermediate roller 34 and also against the inner peripheral surface of the outer ring 40, and a second roller (outer roller) 36 that is spaced circumferentially from the first roller 36 and is pressed against the outer peripheral surface of the intermediate roller 34 and also against the inner peripheral surface of the outer ring 40. The first roller 36 and the second roller 36 have the same size and configuration.

[0031] The pair of outer rollers 36 of each outer roller portion 37 are supported by an outer roller connector 38 in a spaced-apart relationship while being adjacent to each other.

[0032] The outer roller connector 38 includes a plate 38a and a pair of support pins 38b provided on the plate 38a.

[0033] The plate 38a is disposed parallel to the flat portion of the case 30 and is supported in contact with or spaced apart from the flat portion of the case 30. The pair of support pins 38b are formed in a cylindrical or columnar shape and are provided spaced apart on one surface of the plate 38a. The pair of support pins 38b are, for example, fixed to one surface of the plate 38a and integrated therewith. The pair of outer rollers (first roller, second roller) 36 are supported by bearings (not shown) on the pair of support pins 38b so as to be rotatable about axes whose rotation axes are the central axes of the pair of support pins 38b. The outer circumferential surfaces of the pair of outer rollers 36 supported in this manner are spaced apart from each other. Therefore, the outer roller coupler 38 couples the rotation axis of the first roller 36 and the rotation axis of the second roller 36 of each outer roller portion 37, and can rotate the first roller 36 and the second roller 36 in the same direction.

[0034] The inner peripheral surface of the outer ring 40 is formed so as to come into contact with the outer peripheral surfaces of all three pairs of outer rollers 36. The central axis of the outer ring 40 is arranged parallel to the central axes of the sun roller 32, the multiple intermediate rollers 34, and the multiple outer rollers 36. The central axis of the outer ring 40 is also arranged so as to coincide with the central axis of the sun roller 32. It is preferable that the inner peripheral surface of the outer ring 40 is formed to have an appropriate height along the central axis in order to ensure a contact area and contact length with the outer rollers 36.

[0035] As shown in FIG. 3, when the reducer 18 is assembled, the sun roller 32, the intermediate roller 34 supported by the swing arm 44, the outer roller portion 37 supported by the outer roller coupler 38, and the outer ring 40 are assembled to the case 30 in an appropriate order. When these parts are formed with appropriate precision, the reducer 18 is formed in an appropriate fitted state simply by arranging the sun roller 32, the intermediate roller 34 supported by the swing arm 44, the outer roller portion 37 supported by the outer roller coupler 38, and the outer ring 40 to the case 30. Therefore, in the reducer 18, the central axis of the sun roller 32 is located at the position of the central axis of the reducer 18, the intermediate roller 34 is located outside the sun roller 32 radially aligned with the central axis of the sun roller 32, the outer roller portion 37 is located outside the intermediate roller 34 radially aligned with the central axis of the sun roller 32, and the outer ring 40 is located outside the outer roller portion 37 radially aligned with the central axis of the sun roller 32.

[0036] At this time, the intermediate roller 34 supported by the swing arm 44 which rotates around the central axis of the swing arm support pin 42 is positioned at an appropriate position while moving radially between the sun roller 32 and the pair of outer rollers 36 relative to the central axis of the sun roller 32.

[0037] At this time, the outer circumferential surface of the sun roller 32 and the outer circumferential surface of the intermediate roller 34, the outer circumferential surface of the intermediate roller 34 and the outer circumferential surface of the outer roller 36, and the outer circumferential surface of the outer roller 36 and the inner circumferential surface of the outer ring 40 are in linear contact parallel to the central axis of the sun roller 32. The central axes of the sun roller 32, the intermediate roller 34, the outer roller 36, and the outer ring 40 are parallel to one another. Also, the central axis (rotation axis) of the sun roller 32 and the central axis (rotation axis) of the outer ring 40 coincide with each other.

[0038] By forming the reducer 18 in this manner, a pressing load can be generated between the inner peripheral surface of the outer ring 40 and the outer peripheral surface of the outer roller 36, between the outer peripheral surface of the outer roller 36 and the outer peripheral surface of the intermediate roller 34, and further between the outer peripheral surface of the intermediate roller 34 and the outer peripheral surface of the sun roller 32, in a line parallel to the central axis of the sun roller 32. Therefore, the inner peripheral surface of the outer ring 40 and the outer peripheral surface of the outer roller 36, the outer peripheral surface of the outer roller 36 and the outer peripheral surface of the intermediate roller 34, and further between the outer peripheral surface of the intermediate roller 34 and the outer peripheral surface of the sun roller 32 are pressed against each other.

[0039] When assembling the reducer 18, the outer ring 40 may be slightly thermally expanded and then shrink-fitted to fit it around the outer roller 36. In this case, an initial pressure can be generated between the inner peripheral surface of the outer ring 40 and the outer peripheral surface of the outer roller 36. A higher pressing load can be generated linearly parallel to the central axis of the sun roller 32 between the inner peripheral surface of the outer ring 40 and the outer peripheral surface of the outer roller 36, between the outer peripheral surface of the outer roller 36 and the outer peripheral surface of the intermediate roller 34, and further between the outer peripheral surface of the intermediate roller 34 and the outer peripheral surface of the sun roller 32.

[0040] The operation of the reducer 18 according to this embodiment will be described with reference to FIG.

[0041] When a rotational torque is input from the motor 16 to the shaft portion 32a of the sun roller 32 located on the central axis of the sun roller 32, the reducer 18 rotates at that position with the central axis of the sun roller 32 coinciding with the central axis of the reducer 18. Then, the torque is transmitted from the sun roller 32 to the reducer 18, the intermediate roller 34 and the outer roller 36 rotate approximately at that position, and the outer ring 40 rotates around the central axis of the sun roller 32. In this embodiment, the rotation direction of the sun roller 32 and the rotation direction of the outer ring 40 are the same.

[0042] When a rotational torque is input from the motor 16 to the sun roller 32 during torque transmission, a force acts on the outer peripheral surface of the intermediate roller 34 that serves as the friction surface, so as to get between the outer peripheral surface of the sun roller 32 that serves as the friction surface and the outer peripheral surface of the pair of outer rollers 36 that serves as the friction surface, depending on the direction of rotation. At this time, a force continues to act between the outer peripheral surface of the sun roller 32 and the outer peripheral surface of the intermediate roller 34 in the normal direction of the linear contact surface parallel to the central axis of the sun roller 32. At this time, a force continues to act between the outer peripheral surface of the intermediate roller 34 and the outer peripheral surfaces of the pair of outer rollers 36 in the normal direction of the linear contact surface parallel to the central axis of the sun roller 32. At this time, the intermediate roller 34 abuts against the sun roller 32 and the pair of outer rollers 36 at one linear point parallel to the central axis of the sun roller 32. Therefore, the intermediate roller 34 rotates while being supported linearly parallel to the central axis of the sun roller 32 at a total of three points spaced apart from each other by the sun roller 32 and the pair of outer rollers 36. The swing arm 44 rotates within a small range with the central axis of the swing arm support pin 42 as the rotation axis so that the forces in the normal direction between the outer peripheral surface of the sun roller 32 and the outer peripheral surface of the intermediate roller 34 and between the outer peripheral surface of the intermediate roller 34 and the outer peripheral surfaces of the pair of outer rollers 36 are balanced. Therefore, the movement of the intermediate roller 34 can be considered to be along the radial direction with respect to the central axis of the sun roller 32. Therefore, the intermediate roller 34 transmits torque from the sun roller 32 to the pair of outer rollers 36 via the intermediate roller 34 while moving appropriately in the radial direction with respect to the central axis of the sun roller 32. In addition, a force continues to act in the normal direction of the linear contact surface parallel to the central axis of the sun roller 32 between the outer peripheral surfaces of the pair of outer rollers 36 and the inner peripheral surface that serves as the friction surface of the outer ring 40. These three normal directions are parallel to one plane (imaginary plane) parallel to the flat plate-shaped portion of the case 30.

[0043] For this reason, in the reducer 18 according to this embodiment, when a rotational torque is input from the motor 16 to the sun roller 32, the sun roller 32, the intermediate roller 34, and the outer roller 36 are balanced within the outer ring 40. Therefore, when the reducer 18 is operating, the intermediate roller 34 is supported via the swing arm 44, and a large load is prevented from being applied to the swing arm support pin 42 provided on the case 30. For this reason, the reducer 18 according to this embodiment prevents a large load from being applied to the case 30 of the reducer 18.

[0044] Furthermore, according to this embodiment, when rotational torque is input from the motor 16 to the sun roller 32, the reducer 18 can generate a high pressing load on each of the friction surfaces between the outer peripheral surface of the sun roller 32 and the outer peripheral surface of the intermediate roller 34, between the outer peripheral surface of the intermediate roller 34 and the outer peripheral surface of the outer roller 36, and between the outer peripheral surface of the outer roller 36 and the inner peripheral surface of the outer ring 40.

[0045] When a rotational torque is input from the motor 16 to the sun roller 32, the outer peripheral surface of the intermediate roller 34 rotates without slipping relative to the outer peripheral surface of the sun roller 32. Also, the outer peripheral surface of the outer roller 36 rotates without slipping relative to the outer peripheral surface of the intermediate roller 34. And the inner peripheral surface of the outer ring 40 rotates without slipping relative to the outer peripheral surface of the outer roller 36. Therefore, in the speed reducer 18 according to this embodiment, a pressing load proportional to the torque can be generated between the outer peripheral surface of the sun roller 32 and the outer peripheral surface of the intermediate roller 34, between the outer peripheral surface of the intermediate roller 34 and the outer peripheral surfaces of the pair of outer rollers 36 (the outer peripheral surface of the first roller 36 and the outer peripheral surface of the second roller 36), and between the outer peripheral surfaces of the pair of outer rollers 36 (the outer peripheral surface of the first roller 36 and the outer peripheral surface of the second roller 36) and the inner peripheral surface of the outer ring 40. Therefore, by using the reducer 18 according to this embodiment, when rotational torque is input from the motor 16 to the sun roller 32, the pressing load between the sun roller 32 and the intermediate roller 34, the pressing load between the intermediate roller 34 and the outer roller 36, and the pressing load between the outer roller 36 and the outer ring 40 can be transmitted in sequence from the sun roller 32 to the outer ring 40 so that each is proportional to the torque. Therefore, by using the reducer 18 according to this embodiment, the pressing loads can be transmitted in sequence from the sun roller 32 to the outer ring 40 so that each is proportional to the torque when torque is transmitted from the motor 16.

[0046] In addition, when rotation is input to the sun roller 32 during torque transmission from the motor 16, the moving speed (circumferential speed) of the outer peripheral surface of the sun roller 32 and the moving speed (circumferential speed) of the outer peripheral surface of the intermediate roller 34 match or approximately match, the moving speed (circumferential speed) of the outer peripheral surface of the intermediate roller 34 match or approximately match, and the moving speed (circumferential speed) of the outer peripheral surface of the outer roller 36 (the outer peripheral surface of the first roller 36 and the outer peripheral surface of the second roller 36) match or approximately match, and the moving speed (circumferential speed) of the outer peripheral surface of the outer roller 36 (the outer peripheral surface of the first roller 36 and the outer peripheral surface of the second roller 36) match or approximately match. Therefore, in the reducer 18 according to this embodiment, there is no or almost no speed difference in the peripheral speeds of the outer circumferential surface of the sun roller 32, the outer circumferential surface of the intermediate roller 34, the outer circumferential surface of the outer roller 36 (the outer circumferential surface of the first roller 36 and the outer circumferential surface of the second roller 36), and the inner circumferential surface of the outer ring 40. Therefore, in the reducer 18 according to this embodiment, the peripheral speed of the outer circumferential surface of the sun roller 32 and the peripheral speed of the inner circumferential surface of the outer ring 40 are equal, so that the outer ring 40 is slowed down relative to the sun roller 32 by the diameter ratio between them.

[0047] These contents are the same not only when the sun roller 32 receives driving force from the motor 16 and rotates in the direction shown in Fig. 4, but also when it rotates in the opposite direction to the direction shown in Fig. 4. In this case, the outer ring 40 rotates in the opposite direction to the direction shown in Fig. 4 due to the transmission of power.

[0048] Therefore, according to this embodiment, (1) A high pressing load is generated between each friction surface in the reducer 18 when a rotational torque is transmitted from the motor 16 to the reducer 18, (2) making the pressing load proportional to the torque when the rotational torque is transmitted from the motor 16 to the reducer 18; (3) No speed difference is generated within the friction contact surface when the rotational torque is transmitted from the motor 16 to the reducer 18. (4) When the rotational torque is transmitted from the motor 16 to the reducer 18, the case 30 is not subjected to the pressing force of the friction surface. As a result, according to this embodiment, it is possible to provide a friction transmission type reducer 18 that uses, for example, a high rotation speed motor 16, and that achieves high torque transmission efficiency, low vibration and noise, and high reduction ratio deceleration.

[0049] Second embodiment A reducer (roller type reducer) 18 according to the second embodiment will be described with reference to Figures 5 and 6. This embodiment is a modification of the first embodiment, and the same members as those described in the first embodiment are given the same reference numerals, and detailed descriptions will be omitted as much as possible.

[0050] FIG. 5 is a schematic exploded perspective view of the reducer 18 according to the present embodiment.

[0051] As shown in FIG. 5, in this embodiment, the reducer 18 does not include the swing arm support pin 42 provided on the case 30 and the swing arm 44 supported by the swing arm support pin 42.

[0052] The reducer 18 according to this embodiment includes a case (base) 30, a sun roller 32, a plurality of intermediate rollers 34, a plurality of outer rollers 36, a plurality of outer roller couplers 38, an outer ring 40, and a plurality of intermediate roller support portions 52.

[0053] In this embodiment, the case 30 is formed with a plurality of grooves 31 that allow the intermediate roller support portion 52, which supports the intermediate roller 34, to move within a predetermined range in the radial direction relative to the central axis of the sun roller 32.

[0054] FIG. 6 shows the positional relationship between the groove 31 of the case 30 and a slider 54 of an intermediate roller support portion 52, which will be described later.

[0055] 5 and 6, the grooves 31 are formed of a pair of straight line portions 31a and a pair of semicircular portions 31b whose outer edges are parallel to each other, like a track at an athletics stadium, as an example. An imaginary line R extending in a radial direction relative to the central axis of the sun roller 32 intersects with the center of each of the pair of semicircular portions 31b of the grooves 31. Therefore, the grooves 31 extend in a radial direction relative to the central axis of the sun roller 32.

[0056] It is preferable that the groove 31 is formed as a concave groove, but it may be a through groove. When the groove 31 is a through groove, the movement of the slider 54 in the thickness direction of the case 30 is restricted. That is, here, the slider 54 moves parallel to the flat portion of the case 30, and the movement in the thickness direction of the case 30 is ignored.

[0057] The intermediate roller support portion 52 has a slider 54 and an intermediate roller support pin 56 provided on the slider 54 .

[0058] The slider 54 is provided in the case 30 and is used as a moving mechanism for moving the intermediate roller 34 in a radial direction relative to the central axis of the sun roller 32. The slider 54 is, by way of example, formed in a shape and size that fits into the groove portion 31. The slider 54 has a pair of straight portions 54a and a pair of semicircular portions 54b whose outer edges are parallel to each other, like a track in an athletics stadium, for example.

[0059] A distance D1 between the pair of straight portions 31a of the groove 31 is equal to or slightly larger than a distance D2 between the pair of straight portions 54a of the slider 54. In addition, a length L1 of the pair of straight portions 31a of the groove 31 is longer than a length L2 of the pair of straight portions 54a of the slider 54.

[0060] Further, the diameter of the pair of semicircular portions 31b of the groove 31 is equal to or slightly larger than the diameter of the pair of semicircular portions 54b of the slider 54.

[0061] Therefore, the slider 54 disposed in the groove 31 is movable within a predetermined range within the groove 31 along the imaginary line R, which is the longitudinal direction of the groove 31. At this time, the slider 54 allows movement in the radial direction relative to the central axis of the sun roller 32, but restricts movement in the circumferential direction relative to the central axis of the sun roller 32. In other words, the slider 54 is formed to a size relative to the groove 31 that allows movement in the radial direction relative to the central axis of the sun roller 32, but restricts movement in the circumferential direction relative to the central axis of the sun roller 32.

[0062] The slider 54 is provided with an intermediate roller support pin 56. The intermediate roller support pin 56 is formed in a cylindrical or columnar shape.

[0063] The intermediate roller 34 is supported by a bearing (not shown) on the intermediate roller support pin 56 so as to be rotatable about its axis. At this time, the central axis of the intermediate roller 34 coincides with the central axis of the intermediate roller support pin 56.

[0064] As shown in FIG. 5, when the reducer 18 is assembled, the sun roller 32, the intermediate roller 34 supported by the intermediate roller support portion 52, the outer roller portion 37 supported by the outer roller coupler 38, and the outer ring 40 are assembled to the case 30 in an appropriate order. When these parts are formed with appropriate precision, the reducer 18 is formed in an appropriate fitted state simply by arranging the sun roller 32, the intermediate roller 34 supported by the intermediate roller support portion 52, the outer roller portion 37 supported by the outer roller coupler 38, and the outer ring 40 to the case 30. For this reason, the reducer 18 is arranged such that the central axis of the sun roller 32 is located at the position of the central axis of the reducer 18, the intermediate roller 34 is located outside the sun roller 32 radially aligned with the central axis of the sun roller 32, the outer roller portion 37 is located outside the intermediate roller 34 radially aligned with the central axis of the sun roller 32, and the outer ring 40 is located outside the outer roller portion 37 radially aligned with the central axis of the sun roller 32.

[0065] At this time, the slider 54 of the intermediate roller support part 52 is disposed at an appropriate position while appropriately moving in the longitudinal direction (direction along the imaginary line R) of the groove part 31 of the case 30. Therefore, the intermediate roller 34 supported by the intermediate roller support part 52 is disposed at an appropriate position while appropriately moving in the radial direction with respect to the central axis of the sun roller 32 between the sun roller 32 and the pair of outer rollers 36.

[0066] At this time, the outer circumferential surface of the sun roller 32 and the outer circumferential surface of the intermediate roller 34, the outer circumferential surface of the intermediate roller 34 and the outer circumferential surface of the outer roller 36, and the outer circumferential surface of the outer roller 36 and the inner circumferential surface of the outer ring 40 are in linear contact parallel to the central axis of the sun roller 32. The central axes of the sun roller 32, the intermediate roller 34, the outer roller 36, and the outer ring 40 are parallel to one another. Also, the central axis (rotation axis) of the sun roller 32 and the central axis (rotation axis) of the outer ring 40 coincide with each other.

[0067] By forming the reducer 18 in this manner, a pressing load can be generated between the inner peripheral surface of the outer ring 40 and the outer peripheral surface of the outer roller 36, between the outer peripheral surface of the outer roller 36 and the outer peripheral surface of the intermediate roller 34, and further between the outer peripheral surface of the intermediate roller 34 and the outer peripheral surface of the sun roller 32, in a line parallel to the central axis of the sun roller 32. Therefore, the inner peripheral surface of the outer ring 40 and the outer peripheral surface of the outer roller 36, the outer peripheral surface of the outer roller 36 and the outer peripheral surface of the intermediate roller 34, and further between the outer peripheral surface of the intermediate roller 34 and the outer peripheral surface of the sun roller 32 are pressed against each other.

[0068] The operation of the reducer 18 according to this embodiment will be described.

[0069] The operation of the reducer 18 is basically the same as that shown in Fig. 4. When a rotational torque is input from the motor 16 to the shaft portion 32a of the sun roller 32 located on the central axis of the sun roller 32, the reducer 18 rotates at that position with the central axis of the sun roller 32 coinciding with the central axis of the reducer 18. In addition, the reducer 18 receives torque from the sun roller 32, the intermediate roller 34 and the outer roller 36 rotate approximately at that position, and the outer ring 40 rotates around the central axis of the sun roller 32. In this embodiment, the rotation direction of the sun roller 32 and the rotation direction of the outer ring 40 are the same.

[0070] When a rotational torque is input from the motor 16 to the sun roller 32 during torque transmission, a force acts on the outer peripheral surface of the intermediate roller 34 that serves as the friction surface, so as to get between the outer peripheral surface of the sun roller 32 that serves as the friction surface and the outer peripheral surface of the pair of outer rollers 36 that serves as the friction surface, depending on the direction of rotation. At this time, a force continues to act between the outer peripheral surface of the sun roller 32 and the outer peripheral surface of the intermediate roller 34 in the normal direction of the linear contact surface parallel to the central axis of the sun roller 32. At this time, a force continues to act between the outer peripheral surface of the intermediate roller 34 and the outer peripheral surface of the pair of outer rollers 36 in the normal direction of the linear contact surface parallel to the central axis of the sun roller 32. At this time, the outer peripheral surface of the intermediate roller 34 abuts against the outer peripheral surface of the sun roller 32 and the outer peripheral surface of the pair of outer rollers 36 at one linear point parallel to the central axis of the sun roller 32. Therefore, the intermediate roller 34 rotates while being supported linearly parallel to the central axis of the sun roller 32 at a total of three points spaced apart from each other by the sun roller 32 and the pair of outer rollers 36. Then, the slider 54 of the intermediate roller support part 52 that supports the intermediate roller 34 with respect to the groove part 31 of the case 30 moves in a small range in the radial direction (direction along the virtual line R) with respect to the central axis of the sun roller 32 so that the forces in the normal direction between the outer peripheral surface of the sun roller 32 and the outer peripheral surface of the intermediate roller 34 and between the outer peripheral surface of the intermediate roller 34 and the outer peripheral surface of the pair of outer rollers 36 are balanced. Therefore, the intermediate roller 34 transmits torque from the sun roller 32 to the pair of outer rollers 36 via the intermediate roller 34 while moving appropriately in the radial direction with respect to the central axis of the sun roller 32. In addition, a force continues to act in the normal direction of the linear contact surface between the outer peripheral surfaces of the pair of outer rollers 36 and the inner peripheral surface of the outer ring 40, which is parallel to the central axis of the sun roller 32. These three normal directions are parallel to one plane (virtual plane) parallel to the flat plate part of the case 30.

[0071] For this reason, in the reducer 18 according to this embodiment, when rotational torque is input from the motor 16 to the sun roller 32, the sun roller 32, the intermediate rollers 34, and the outer rollers 36 are balanced within the outer ring 40. Therefore, when the reducer 18 is operating, the intermediate roller support parts 52 that support the intermediate rollers prevent a large load from being applied to the groove parts 31 of the case 30. For this reason, the reducer 18 according to this embodiment prevents a large load from being applied to the case 30 of the reducer 18.

[0072] Furthermore, according to this embodiment, when rotational torque is input from the motor 16 to the sun roller 32, the reducer 18 can generate a high pressing load on each of the friction surfaces between the outer peripheral surface of the sun roller 32 and the outer peripheral surface of the intermediate roller 34, between the outer peripheral surface of the intermediate roller 34 and the outer peripheral surface of the outer roller 36, and between the outer peripheral surface of the outer roller 36 and the inner peripheral surface of the outer ring 40.

[0073] When a rotational torque is input from the motor 16 to the sun roller 32, the outer peripheral surface of the intermediate roller 34 rotates without slipping relative to the outer peripheral surface of the sun roller 32. Also, the outer peripheral surface of the outer roller 36 rotates without slipping relative to the outer peripheral surface of the intermediate roller 34. And the inner peripheral surface of the outer ring 40 rotates without slipping relative to the outer peripheral surface of the outer roller 36. Therefore, in the speed reducer 18 according to this embodiment, a pressing load proportional to the torque can be generated between the outer peripheral surface of the sun roller 32 and the outer peripheral surface of the intermediate roller 34, between the outer peripheral surface of the intermediate roller 34 and the outer peripheral surfaces of the pair of outer rollers 36 (the outer peripheral surface of the first roller 36 and the outer peripheral surface of the second roller 36), and between the outer peripheral surfaces of the pair of outer rollers 36 (the outer peripheral surface of the first roller 36 and the outer peripheral surface of the second roller 36) and the inner peripheral surface of the outer ring 40. Therefore, by using the reducer 18 according to this embodiment, when rotational torque is input from the motor 16 to the sun roller 32, the pressing load between the sun roller 32 and the intermediate roller 34, the pressing load between the intermediate roller 34 and the outer roller 36, and the pressing load between the outer roller 36 and the outer ring 40 can be transmitted in sequence from the sun roller 32 to the outer ring 40 so that each is proportional to the torque. Therefore, by using the reducer 18 according to this embodiment, the pressing loads can be transmitted in sequence from the sun roller 32 to the outer ring 40 so that each is proportional to the torque when torque is transmitted from the motor 16.

[0074] In addition, when rotation is input to the sun roller 32 during torque transmission from the motor 16, the moving speed (circumferential speed) of the outer peripheral surface of the sun roller 32 and the moving speed (circumferential speed) of the outer peripheral surface of the intermediate roller 34 match or approximately match, the moving speed (circumferential speed) of the outer peripheral surface of the intermediate roller 34 match or approximately match, and the moving speed (circumferential speed) of the outer peripheral surface of the outer roller 36 (the outer peripheral surface of the first roller 36 and the outer peripheral surface of the second roller 36) match or approximately match, and the moving speed (circumferential speed) of the outer peripheral surface of the outer roller 36 (the outer peripheral surface of the first roller 36 and the outer peripheral surface of the second roller 36) match or approximately match. Therefore, in the reducer 18 according to this embodiment, there is no or almost no speed difference in the peripheral speeds of the outer circumferential surface of the sun roller 32, the outer circumferential surface of the intermediate roller 34, the outer circumferential surface of the outer roller 36 (the outer circumferential surface of the first roller 36 and the outer circumferential surface of the second roller 36), and the inner circumferential surface of the outer ring 40. Therefore, in the reducer 18 according to this embodiment, the peripheral speed of the outer circumferential surface of the sun roller 32 and the peripheral speed of the inner circumferential surface of the outer ring 40 are equal, so that the outer ring 40 is slowed down relative to the sun roller 32 by the diameter ratio between them.

[0075] These contents are the same not only when the sun roller 32 receives driving force from the motor 16 and rotates in the direction shown in Fig. 4, but also when it rotates in the opposite direction to the direction shown in Fig. 4. In this case, the outer ring 40 rotates in the opposite direction to the direction shown in Fig. 4 due to the transmission of power.

[0076] Therefore, according to this embodiment, (1) A high pressing load is generated between each friction surface in the reducer 18 when a rotational torque is transmitted from the motor 16 to the reducer 18, (2) making the pressing load proportional to the torque when the rotational torque is transmitted from the motor 16 to the reducer 18; (3) No speed difference is generated within the friction contact surface when the rotational torque is transmitted from the motor 16 to the reducer 18. (4) When the rotational torque is transmitted from the motor 16 to the reducer 18, the case 30 is not subjected to the pressing force of the friction surface. As a result, according to this embodiment, it is possible to provide a friction transmission type reducer 18 that uses, for example, a high rotation speed motor 16, and that achieves high torque transmission efficiency, low vibration and noise, and high reduction ratio deceleration.

[0077] The present invention is not limited to the above-mentioned embodiment, and can be modified in various ways without departing from the gist of the present invention. The embodiments may be combined as appropriate, and in that case, the combined effect can be obtained. Furthermore, the above-mentioned embodiment includes various inventions, and various inventions can be extracted by combinations selected from the multiple components disclosed. For example, if the problem can be solved and the effect can be obtained even if some components are deleted from all the components shown in the embodiment, the configuration from which the components are deleted can be extracted as an invention. The following is a summary of the claims of this application as filed. [Appendix 1] Case and a sun roller having a rotation axis that coincides with the central axis and that rotates around the axis of the rotation axis relative to the case when rotation is input; a plurality of intermediate rollers each having an outer circumferential surface pressed against the outer circumferential surface of the sun roller and rotating in response to the rotation of the sun roller; a moving mechanism supported by the case, rotatably supporting each of the intermediate rollers, and moving the intermediate rollers relative to the sun roller in a radial direction with respect to the central axis of the sun roller; a plurality of outer rollers each having an outer circumferential surface pressed against an outer circumferential surface of the plurality of intermediate rollers and rotating in response to the rotation of the intermediate rollers; an outer ring having an inner circumferential surface pressed against an outer circumferential surface of the outer roller and rotating in response to the rotation of the outer roller; A reducer having [Appendix 2] the moving mechanism includes a swing arm that is swingably mounted on the case and moves the intermediate roller in a radial direction relative to the central axis of the sun roller with respect to the sun roller and the outer roller. 2. A reducer as defined in claim 1. [Appendix 3] the moving mechanism includes a slider that is movable relative to the case in a radial direction relative to the central axis of the sun roller and that moves the intermediate roller relative to the sun roller and the outer roller in the radial direction relative to the central axis of the sun roller. 2. A reducer as defined in claim 1. [Appendix 4] Each of the outer rollers is a first roller that is pressed against an outer circumferential surface of the intermediate roller and against an inner circumferential surface of the outer ring; a second roller that is spaced apart from the first roller in a circumferential direction and is pressed against an outer circumferential surface of the intermediate roller and against an inner circumferential surface of the outer ring; Equipped with The reducer has a coupler that connects a rotation shaft of the first roller and a rotation shaft of the second roller and rotates the first roller and the second roller in the same direction. 4. The reducer according to claim 1, [Appendix 5] A reducer according to any one of Supplementary Note 1 to Supplementary Note 3; a motor for inputting a driving force to the sun roller of the reduction gear; a battery that supplies power to drive the motor; A vehicle having the above configuration. [Appendix 6] 1. An electric vehicle comprising the vehicle according to appended claim 5. [Explanation of symbols]

[0078] 10...electric vehicle, 10a...vehicle, 12...battery, 14...inverter, 16...motor, 18...reduction gear, 20...drive shaft, 22...wheel, 30...case, 31...groove portion, 31a...straight portion, 31b...semicircular portion, 32...sun roller, 32a...shaft portion, 34...intermediate roller, 36...outer roller, 37...outer roller portion, 38...outer roller coupler, 38a...plate, 38b...support pin, 40...outer ring, 42...swing arm support pin, 44...swing arm, 44a...cylindrical portion, 44b...plate, 44c...intermediate roller support pin, 52...intermediate roller support portion, 54...slider, 54a...straight portion, 54b...semicircular portion, 56...intermediate roller support pin.

Claims

1. Case and a sun roller having a rotation axis that coincides with the central axis and that rotates around the axis of the rotation axis relative to the case when rotation is input; a plurality of intermediate rollers each having an outer circumferential surface pressed against the outer circumferential surface of the sun roller and rotating in response to the rotation of the sun roller; a moving mechanism supported by the case, rotatably supporting each of the intermediate rollers, and moving the intermediate rollers relative to the sun roller in a radial direction with respect to the central axis of the sun roller; a first roller having an outer circumferential surface pressed against an outer circumferential surface of the intermediate roller and rotating in response to the rotation of the intermediate roller; and a second roller that is spaced apart from the first roller in the circumferential direction, has an outer circumferential surface that is pressed against the outer circumferential surface of the intermediate roller that is the same as the outer circumferential surface of the first roller, and rotates in response to the rotation of the intermediate roller; A plurality of outer roller portions each having a first coupler that couples a rotation shaft of the first roller and a rotation shaft of the second roller of one of the outer roller units, rotates the first roller and the second roller in the same direction in response to the rotation of the intermediate roller, and abuts against or separates from the case; and a second coupler that connects a rotation shaft of the first roller and a rotation shaft of the second roller of another one of the plurality of outer roller units, rotates the first roller and the second roller in the same direction in response to the rotation of the intermediate roller, and abuts against or is separated from the case, and is spaced apart in the circumferential direction from the first coupler; an outer ring having an outer circumferential surface that is pressed against the outer circumferential surface of the first roller and the outer circumferential surface of the second roller that are connected by the first coupler of the outer roller part, and the outer circumferential surface of the first roller and the outer circumferential surface of the second roller that are connected by the second coupler, and which rotates in response to rotation of the first roller and the second roller of the outer roller part; A reducer having

2. the moving mechanism includes a swing arm that is swingably mounted on the case and moves the intermediate roller in a radial direction relative to the central axis of the sun roller with respect to the sun roller and the outer roller portion. The reducer according to claim 1 .

3. the moving mechanism is provided with a slider that is movable in a radial direction with respect to the central axis of the sun roller with respect to the case, and that moves the intermediate roller in the radial direction with respect to the central axis of the sun roller with respect to the sun roller and the outer roller portion. The reducer according to claim 1 .

4. The first coupler and the second coupler each include: A plate that comes into contact with or is spaced from the case; a pair of support pins provided on one surface side of the plate at a distance from each other and rotatably supporting an outer circumferential surface of the first roller and an outer circumferential surface of the second roller in a spaced-apart state; The reducer according to claim 1 , further comprising:

5. A reducer according to any one of claims 1 to 3; a motor for inputting a driving force to the sun roller of the reduction gear; a battery that supplies power to drive the motor; A vehicle having the above configuration.

6. An electric vehicle comprising the vehicle according to claim 5.

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