Power transmission device

Abstract

The invention provides a power transmission device capable of suppressing the manufacturing cost without increasing the precision of each component. The drive unit (10) is provided with a drive sprocket (21a), a drive shaft (21) that supports the drive sprocket (21a), a driven sprocket (311a), a rotating shaft (311b) that supports the driven sprocket (311a), and a power transmission chain (40) that is wound around the drive sprocket (21a) and the driven sprocket (311a). At least one of the drive sprocket (21a) and the driven sprocket (311a) is provided so as to be movable in the axial direction. The power transmission chain (40) has a guide plate (410) that restricts the axial movement of at least one of the drive sprocket (21a) and the driven sprocket (311a).

Description

Technical Field

[0001] The invention relates to a power transmission device. Background Art

[0002] Conventionally, there is known a power transmission device in which an endlessly flexible member such as a chain or a belt is wound around a driving sprocket and a driven sprocket to transmit power via the endlessly flexible member (for example, Patent Documents 1 to 3).

[0003] In such a power transmission device, it is generally configured so that the drive sprocket and the driven sprocket are positioned in the axial direction with high accuracy and the amount of deviation in the axial direction is limited to within the width of the endless flexible member.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2007-154913

[0007] Patent Document 2: Japanese Patent Application Publication No. 2011-236943

[0008] Patent Document 3: Japanese Patent Application Publication No. 2016-61337 Summary of the invention

[0009] Problems to be solved by the invention

[0010] However, in order to position the drive sprocket and the driven sprocket with high accuracy in the axial direction, components supporting the drive sprocket and the driven sprocket also need to be formed with high accuracy, which is a cause of increased manufacturing cost.

[0011] The present invention provides a power transmission device capable of reducing manufacturing costs.

[0012] Solutions to Solve Problems

[0013] The present invention provides a power transmission device, comprising:

[0014] a first rotating member;

[0015] a first rotating shaft supporting the first rotating member;

[0016] a second rotating member;

[0017] a second rotating shaft supporting the second rotating member; and

[0018] an endless flexible member, which is wound around the first rotating member and the second rotating member,

[0019] in,

[0020] At least one of the first rotating member and the second rotating member is arranged to be movable in the axial direction.

[0021] The endless flexible member includes a restriction portion that restricts movement of at least one of the first rotating member and the second rotating member in the axial direction.

[0022] Effects of the Invention

[0023] According to the present invention, it is possible to suppress the manufacturing cost without increasing the accuracy of each component. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of a vehicle equipped with a drive unit 10 according to an embodiment of the present invention, as viewed from the left.

[0025] Figure 2 This is a perspective view showing a partially cutaway view of a drive unit 10 according to an embodiment of the present invention.

[0026] Figure 3 It is used to illustrate Figure 2 A partially cutaway stereoscopic view of a power transmission path in the drive unit 10.

[0027] Figure 4 yes Figure 2 A skeleton diagram of the reduction device in the drive unit 10.

[0028] Figure 5 It is a cross-sectional view for explaining the support structure of the drive shaft 21 .

[0029] Figure 6 It is an exploded perspective view of a part of the power transmission chain 40 .

[0030] Figure 7 It is a cross-sectional perspective view of the chain transmission mechanism 4.

[0031] Figure 8 It is an explanatory diagram for explaining the movable width D of the driving shaft 21 .

[0032] Description of reference numerals:

[0033] 10 Drive unit (power transmission device)

[0034] 20a Motor shaft (output part)

[0035] 20b sliding groove

[0036] 21 driving shaft (first rotating shaft)

[0037] 21a driving sprocket (first rotating member)

[0038] 25 card holder

[0039] 40 Power transmission chain (endless flexible parts)

[0040] 311 Input shaft (input part)

[0041] 311a Driven sprocket (second rotating member)

[0042] 311b Rotation axis (second rotation axis)

[0043] 410 guide plate (limiting part)

[0044] 411 Guidance Department

[0045] L1 width

[0046] L2 width. DETAILED DESCRIPTION

[0047] Hereinafter, a vehicle equipped with a drive unit according to an embodiment of the present invention will be described based on the accompanying drawings. In addition, the accompanying drawings are viewed along the directions indicated by the accompanying drawings. In addition, in this specification, etc., in order to make the description simple and clear, the front and rear, left and right, and up and down directions are described according to the directions observed from the driver of the vehicle. In the accompanying drawings, the front of the vehicle is represented as Fr, the rear is represented as Rr, the left is represented as L, the right is represented as R, the top is represented as U, and the bottom is represented as D.

[0048]

Overall structure of the vehicle

[0049] like Figure 1 As shown, the vehicle V of this embodiment has a pair of left and right front wheels FW and a pair of left and right rear wheels RW, and a bottom panel FP constituting the bottom surface of the vehicle V. The vehicle V is divided into a vehicle compartment CB and a front cabin FRM in front thereof by a front control panel DP extending in the up-down direction above the bottom panel FP. Front seats FS and rear seats RS are provided in the vehicle compartment CB.

[0050] The vehicle V includes a drive unit 10 as a drive source and a battery unit IPU that stores electric power to be supplied to the drive unit 10 .

[0051] The drive unit 10 is arranged below the floor panel FP behind the rear seat RS. The battery pack IPU is arranged below the bottom surface of the vehicle compartment CB below the floor panel FP. The battery pack IPU accommodates a plurality of battery modules in which a plurality of cells are stacked. Each cell is a secondary battery capable of charge and discharge, such as a lithium-ion battery or an all-solid-state battery.

[0052] [Overall structure of the drive unit]

[0053] like Figure 2 and Figure 3As shown, the drive unit 10 includes a drive motor 20, a reduction device 30 that reduces the power output from the drive motor 20 and outputs it to the outside, a chain transmission mechanism 4 that transmits the power output from the drive motor 20 to the reduction device 30, a control device 50 that controls the drive motor 20, and a drive unit housing 11 that accommodates them.

[0054] The drive unit case 11 has a main case 111 , a left side cover 112 covering the left side surface of the main case 111 , and a right side cover 113 covering the right side surface of the main case 111 .

[0055] The drive unit housing 11 has a motor chamber 12 that accommodates the drive motor 20, a gear chamber 13 that accommodates the reduction gear 30, a chain chamber 14 that accommodates the chain transmission mechanism 4, and a controller chamber 15 that accommodates the control device 50. The motor chamber 12 and the gear chamber 13 are arranged in the front-to-back direction in a manner such that the motor chamber 12 is in the front and the gear chamber 13 is in the rear. The chain chamber 14 is formed on the left side of the motor chamber 12 and the gear chamber 13, and is formed by a main housing 111 and a left side cover 112. The controller chamber 15 is formed on the right side of the motor chamber 12 and the gear chamber 13, and is formed by a main housing 111 and a right side cover 113.

[0056] The driving motor 20 is a so-called inner rotor type motor, which includes a motor shaft 20a, a rotor 22 mounted on the motor shaft 20a and rotating integrally with the motor shaft 20a, and a stator 23 arranged to be radially opposed to the rotor 22 with a small gap radially outside the rotor 22.

[0057] In the present embodiment, in the drive unit 10, the drive motor 20 is configured so that the axial direction (i.e., the motor shaft 20a) is horizontally oriented in the left-right direction. Thus, by configuring the motor shaft 20a in a manner oriented in the horizontal direction, the vertical dimensions of the drive unit 10 can be made compact. In addition, in the following description, the extending direction of the motor shaft 20a is referred to as the axial direction.

[0058] The stator 23 includes a stator core 231 and a coil 232 mounted on the stator core 231 and composed of a plurality of windings such as a U-phase, a V-phase, and a W-phase.

[0059] The motor shaft 20a is coupled to the drive shaft 21. The drive shaft 21 is coupled to the motor shaft 20a in a manner that it cannot rotate relative to the motor shaft 20a but can move relative to the motor shaft 20a in the axial direction. Figure 5As shown in the figure, on the outer peripheral surface of one end 21R (the right end in this embodiment) of the drive shaft 21 passing through the inner peripheral portion of the motor shaft 20a, a clip 25 (for example, a C-type clip) is fitted in a clip groove 21b in a manner that cannot move relatively. On the other hand, a sliding groove 20b is provided in the inner peripheral portion of the motor shaft 20a, in which the clip 25 fixed to the drive shaft 21 can slide. Here, the width L2 of the slidable area defined by the drive shaft 21 and the sliding groove 20b of the motor shaft 20a is wider than the width L1 of the clip 25.

[0060] The other end 21L (the left end in the embodiment) of the drive shaft 21 is connected to the front boss 112f (see FIG. Figure 2 ) is supported to be freely rotatable by a cylindrical roller bearing (roller bearing) 77 provided on the inner circumferential surface of the left cover 112. The cylindrical roller bearing 77 has a smaller supporting force against an axial load (axial load) than a ball bearing or a tapered roller bearing. Therefore, the drive shaft 21 is allowed to move axially relative to the motor shaft 20a and the left cover 112 within the width L2 of the slidable area. In addition, the drive shaft 21 rotates integrally with the motor shaft 20a, so in the following description, the drive shaft 21 is sometimes referred to as the drive shaft 21 of the drive motor 20.

[0061] The drive sprocket 21a around which the power transmission chain 40 of the chain transmission mechanism 4 is wound is fixed to the left end of the drive shaft 21 in a manner that is non-rotatable relative to the drive shaft 21 and non-movable axially relative to the drive shaft 21. That is, the drive sprocket 21a is provided to be movable axially relative to the motor shaft 20a and the drive unit housing 11 and to rotate integrally with the drive shaft 21.

[0062] The chain transmission mechanism 4 includes a driving sprocket 21a mounted on the driving shaft 21, a driven sprocket 311a mounted on the input shaft 311 of the planetary gear mechanism 31 described later on the same plane as the driving sprocket 21a, and a power transmission chain 40 wound around the driving sprocket 21a and the driven sprocket 311a. The diameter of the driven sprocket 311a is larger than that of the driving sprocket 21a, and the number of teeth of the driven sprocket 311a is greater than that of the driving sprocket 21a.

[0063] like Figure 3 and Figure 4 As shown, the reduction gear device 30 includes a planetary gear mechanism 31 and a differential gear mechanism 32 .

[0064] The planetary gear mechanism 31 includes an input shaft 311 , a sun gear 312 , a plurality of planetary pinion shafts 313 , the same number of stepped pinion gears 314 as the planetary pinion shafts 313 , a planetary carrier 316 , and a ring gear 317 .

[0065] In the present embodiment, the planetary gear mechanism 31 is arranged in the front-to-back direction behind the driving motor 20. The planetary gear mechanism 31 is arranged so that the axial direction (i.e., the input shaft 311) is parallel to the axial direction of the driving motor 20 and faces the left-right direction. In addition, the input shaft 311 of the planetary gear mechanism 31 is arranged at a position at substantially the same height as the driving shaft 21 of the driving motor 20 in the vertical direction. In addition, the outer diameter of the planetary gear mechanism 31 is substantially the same as the outer diameter of the driving motor 20, and the height of the driving unit 10 in the vertical direction is low.

[0066] The input shaft 311 is a hollow shaft, and the left drive shaft 325L described later passes through the inside of the input shaft 311. The rotating shaft 311b of the driven sprocket 311a on which the power transmission chain 40 of the chain transmission mechanism 4 is wound is fixed to the left end of the input shaft 311 in a manner that it cannot rotate relative to the input shaft 311 and cannot move axially relative to the input shaft 311. The driven sprocket 311a is fixed to the rotating shaft 311b in a manner that it cannot rotate relative to the rotating shaft 311b and cannot move axially relative to the rotating shaft 311b. That is, the driven sprocket 311a rotates integrally with the input shaft 311 in a manner that it cannot move axially relative to the input shaft 311 and the drive unit housing 11. In this embodiment, the driven sprocket 311a and the rotating shaft 311b are integrally formed, but not limited to this. As long as the driven sprocket 311a is fixed to the rotating shaft 311b in a manner that it cannot rotate relative to the rotating shaft 311b and cannot move axially relative to the rotating shaft 311b, it can also be formed separately from the rotating shaft 311b.

[0067] The sun gear 312 is an external gear provided on the input shaft 311 , and rotates integrally with the input shaft 311 on the same rotation axis.

[0068] The plurality of pinion shafts 313 are arranged at equal intervals in the circumferential direction and radially outside the sun gear 312 along the outer peripheral surface of the sun gear 312 so as to face the left-right direction in parallel with the input shaft 311 .

[0069] The stepped pinion gear 314 including the first planetary gear 314 a and the second planetary gear 314 b that rotate integrally is supported on each of the planetary pinion shafts 313 so as to be freely rotatable.

[0070] The first planetary gear 314 a is an external gear that is disposed on the outer peripheral surface of the sun gear 312 and meshes with the sun gear 312 .

[0071] The second planetary gear 314 b is an external gear that is disposed on the inner peripheral surface of the ring gear 317 and meshes with the ring gear 317 .

[0072] The planetary carrier 316 is connected to the planetary pinion shaft 313. The planetary carrier 316 and the planetary pinion shaft 313 are integrally rotatable on a rotation axis coaxial with the input shaft 311 (and the sun gear 312).

[0073] Therefore, the stepped pinion 314 having the first planetary gear 314a and the second planetary gear 314b freely rotates about the planetary pinion shaft 313, and freely revolves on a rotation axis coaxial with the input shaft 311 (and the sun gear 312) in an integrated manner with the planetary pinion shaft 313. Furthermore, the planet carrier 316 rotates on a rotation axis coaxial with the input shaft 311 (and the sun gear 312) in an integrated manner with the revolving motion of the stepped pinion 314.

[0074] The ring gear 317 is an annular internal gear whose inner circumference meshes with each second planetary gear 314b. In the present embodiment, the ring gear 317 is fixed to the drive unit housing 11, and the ring gear 317 itself does not rotate. The differential gear mechanism 32 includes a differential case 321, a differential pinion shaft 322 supported by the differential case 321, a first bevel gear 323a and a second bevel gear 323b supported by the differential pinion shaft 322 so as to be freely rotatable, a left side gear 324L and a right side gear 324R meshed with the first bevel gear 323a and the second bevel gear 323b, and a left drive shaft 325L and a right drive shaft 325R.

[0075] The differential case 321 is formed integrally with the carrier 316 of the planetary gear mechanism 31. Therefore, the differential case 321 rotates integrally with the carrier 316 of the planetary gear mechanism 31 on a rotation axis coaxial with the input shaft 311.

[0076] Next, a power transmission path of the power output from the driving motor 20 will be described.

[0077] The power generated by the driving motor 20 is output from the motor shaft 20a, and the driving shaft 21 and the driving sprocket 21a mounted on the driving shaft 21 rotate integrally with the motor shaft 20a. Moreover, when the driving sprocket 21a rotates, the driven sprocket 311a rotates due to the power transmission chain 40 wound on the driving sprocket 21a and the driven sprocket 311a mounted on the input shaft 311 of the planetary gear mechanism 31. Moreover, the input shaft 311 of the planetary gear mechanism 31 rotates integrally with the driven sprocket 311a. At this time, the number of teeth of the driven sprocket 311a is greater than the number of teeth of the driving sprocket 21a, so the rotation of the driving shaft 21 is decelerated via the driving sprocket 21a, the power transmission chain 40 and the driven sprocket 311a, and is input to the input shaft 311 of the planetary gear mechanism 31 via the rotating shaft 311b.

[0078] In the planetary gear mechanism 31, the power input to the input shaft 311 is transmitted to the stepped pinion 314 via the sun gear 312. And, the stepped pinion 314 rotates while revolving. And, the planet carrier 316 rotates integrally with the revolving of the stepped pinion 314. In the planetary gear mechanism 31, since the ring gear 317 is fixed, the rotation of the input shaft 311 is decelerated at a predetermined reduction ratio and transmitted to the planet carrier 316.

[0079] In the differential gear mechanism 32, the differential case 321 is formed integrally with the planetary carrier 316 of the planetary gear mechanism 31, and thus rotates integrally with the rotation of the planetary carrier 316. Therefore, the power input to the input shaft 311 of the planetary gear mechanism 31 is reduced in speed at a predetermined reduction ratio and input to the differential case 321 via the planetary carrier 316.

[0080] Therefore, the power output from the drive shaft 21 is input to the differential case 321 of the differential gear mechanism 32 via the power transmission chain 40 and the planetary gear mechanism 31 , and the differential pinion shaft 322 revolves together with the differential case 321 about the rotation axis of the differential case 321 .

[0081] When the vehicle V is traveling straight, there is no rotation difference between the left and right rear wheels RW, so the left side gear 324L and the right side gear 324R meshing with the first bevel gear 323a and the second bevel gear 323b rotate in accordance with the rotation of the differential pinion shaft 322. In addition, the left drive shaft 325L rotates integrally with the rotation of the left side gear 324L, thereby rotating the left rear wheel RW, and the right drive shaft 325R rotates integrally with the rotation of the right side gear 324R, thereby rotating the right rear wheel RW.

[0082] When the vehicle V turns, the differential pinion shaft 322 revolves, and the first bevel gear 323a and the second bevel gear 323b rotate to slow down the rotation speed of the rear wheel RW on the inner side of the turn and speed up the rotation speed of the rear wheel RW on the outer side of the turn, and the left side gear 324L and the right side gear 324R meshing with the first bevel gear 323a and the second bevel gear 323b rotate at different rotation speeds to slow down the rotation speed of the rear wheel RW on the inner side of the turn and speed up the rotation speed of the rear wheel RW on the outer side of the turn. Moreover, the left drive shaft 325L rotates integrally with the rotation of the left side gear 324L, thereby rotating the rear wheel RW on the left side, and the right drive shaft 325R rotates integrally with the rotation of the right side gear 324R, thereby rotating the rear wheel RW on the right side. Therefore, when the vehicle V turns, the left drive shaft 325L and the right drive shaft 325R rotate in a manner that slows down the rotation speed of the rear wheel RW on the inner side of the turn and speeds up the rotation speed of the rear wheel RW on the outer side of the turn.

[0083] In this way, Figure 3As shown by the arrow, the power output from the driving motor 20 is decelerated and input into the reduction device 30 via the driving sprocket 21a, the driven sprocket 311a and the power transmission chain 40, further decelerated by the planetary gear mechanism 31, and the power is appropriately distributed and transmitted to the left and right rear wheels RW by the differential gear mechanism 32.

[0084] Next, refer to Figure 6 and Figure 7 The structure of the power transmission chain 40 will be described.

[0085] The power transmission chain 40 is axially arranged with a plurality of ring plates 401 arranged in a ring shape in the traveling direction in a plurality of rows, and the ring plates 401 arranged in a ring shape in a plurality of rows are connected by pins 403 penetrating in the axial direction. More specifically, on each ring plate 401, two through holes 401a and 401b penetrating in the axial direction are formed in a manner arranged in the traveling direction, and the pin 403 penetrates through holes 401a and 401b different from those of the ring plates 401 in the rows adjacent in the axial direction. That is, when focusing on one pin 403, the pin 403 penetrates through the through hole 401a of the ring plate 401 and the through hole 401b of the ring plate 401 alternately in the axial direction. The pin 403 is arranged in all the through holes 401a and 401b.

[0086] Thus, the multiple rows of ring plates 401 configured in an annular shape are connected in the axial direction and the traveling direction, forming an endless (jointless) ring shape. A groove portion 401c is formed between the through holes 401a and 401b on each ring plate 401 to mesh with the teeth of the sprockets 21a and 311a. Thus, the rotation of the driving sprocket 21a is transmitted to the driven sprocket 311a via the power transmission chain 40.

[0087] Furthermore, the pins 403 protrude from the ring plate 401 on one axial end side and the ring plate 401 on the other axial end side to both sides in the axial direction.

[0088] A pair of left and right guide plates 410 are arranged outside the ring plate 401 at one axial end and the ring plate 401 at the other axial end. The guide plates 410 are formed so that through holes 410a and 410b are arranged in the running direction and the protrusions of the pins 403 are pressed into the through holes.

[0089] The guide plate 410 has a guide portion 411 that overlaps with the teeth of the sprockets 21 a and 311 a when viewed from the axial direction. That is, the groove portion 401 c of the ring plate 401 is not formed on the guide plate 410 .

[0090] Here, if Figure 7 As shown, the distance L3 between the pair of left and right guide plates 410 is longer than the axial length L4 of the sprockets 21a and 311a. That is, the sprockets 21a and 311a and the power transmission chain 40 are configured to be relatively movable in the axial direction.

[0091] As described above, in this embodiment, the axial movement of the drive shaft 21 is allowed, so it is not necessary to set the position accuracy of the drive shaft 21 and the input shaft 311 with high precision. That is, the driven sprocket 311a supported by the input shaft 311 is input with a thrust load (axial load) through the meshing of the sun gear 312 and the first planetary gear 314a of the stepped pinion 314. In contrast, there is no speed reduction mechanism between the drive motor 20 and the drive sprocket 21a, so no thrust load is generated. Therefore, the drive shaft 21 can have axial freedom.

[0092] By utilizing this, the drive shaft 21 is supported in a manner that allows the axial movement of the drive shaft 21, so that even when there is an axial positional deviation of the driven sprocket 311a, the guide plate 410 of the power transmission chain 40 abuts against the outer end surface of the sprocket 21a, and the sprocket 21a can move with the swing of the power transmission chain 40. In this way, in the drive unit 10, the axial deviation can be absorbed by the movement of the drive shaft 21, so it is not necessary to manage the drive shaft 21 and the input shaft 311 with high precision.

[0093] Next, refer to Figure 8 The movable width of the drive shaft 21 (hereinafter referred to as the movable width of the drive sprocket 21 a ) will be described.

[0094] exist Figure 8 In the chain transmission mechanism 4 in which the driving sprocket 21a can move axially and the driven sprocket 311a cannot move axially, the upper figure shows the positional relationship when the driven sprocket 311a has no axial position deviation, and the lower figure shows the positional relationship when the driven sprocket 311a has an axial position deviation width.

[0095] exist Figure 8 In the figure, the DR axis represents the axis center of the driving sprocket 21a (driving shaft 21), the DN axis represents the axis center of the driven sprocket 311a (input shaft 311), and the reference position is a reference line passing through the axial center of the driving sprocket 21a and the axial center of the driven sprocket 311a when there is no axial position deviation of the driven sprocket 311a.

[0096] When the inner width of the power transmission chain 40 is set to A, the width of the driving sprocket 21a is set to B, the width of the driven sprocket 311a is set to C, the movable width of the driving sprocket 21a is set to D1, and the position deviation width of the driven sprocket 311a is set to E1, as shown in FIG. Figure 8 As shown, the movable width D of the driving sprocket 21a is expressed by the following formula (1).

[0097] D1=E1+C / 2+B / 2-A(1)

[0098] That is, in the drive unit 10, the position deviation width E1 of the driven sprocket 311a can be allowed. In this case, the driving sprocket 21a can be set to be movable with a movable width D1. In other words, if the support structure of the driving sprocket 21a (driving shaft 21) has a movable width D1, the support structure of the driven sprocket 311a (input shaft 311) can be allowed to have a position deviation width E1.

[0099] The movable width D1 of the drive sprocket 21a for preventing the power transmission chain 40 and the drive sprocket 21a from interfering with each other in the axial direction even when there is a positional deviation width E1 of the driven sprocket 311a is expressed by the following formula (2).

[0100] D1>E1+C / 2+B / 2-A(2)

[0101] By setting the movable width D1 of the drive sprocket 21 a so as to satisfy the above-mentioned formula (2), it is possible to avoid contact between the power transmission chain 40 and the drive sprocket 21 a.

[0102] In addition, in the above-mentioned embodiment, the clamp 25 is fixed to the outer peripheral surface of the drive shaft 21 passing through the inner peripheral portion of the motor shaft 20a, and the sliding groove 20b in which the clamp 25 can slide is provided on the inner peripheral portion of the motor shaft 20a, so that the motor shaft 20a and the drive shaft 21 can move relative to each other in the axial direction, but the present invention is not limited thereto. That is, the clamp 25 may be fixed to the inner peripheral surface of the motor shaft 20a, and the sliding groove in which the clamp 25 can slide is provided on the outer peripheral surface of the drive shaft 21, so that the motor shaft 20a and the drive shaft 21 can move relative to each other in the axial direction.

[0103] In addition, in the above-mentioned embodiment, the drive shaft 21 supporting the drive sprocket 21a is coupled to the motor shaft 20a in a manner that is non-rotatable relative to the motor shaft 20a and can move relative to the motor shaft 20a in the axial direction, and the rotating shaft 311b supporting the driven sprocket 311a is coupled to the input shaft 311 in a manner that is non-rotatable relative to the input shaft 311 and cannot move relative to the input shaft 311 in the axial direction. In other words, the drive sprocket 21a can move in the axial direction, and the driven sprocket 311a cannot move. However, the present invention is not limited to this, and the drive shaft 21 supporting the drive sprocket 21a may be coupled to the motor shaft 20a in a manner that is non-rotatable relative to the motor shaft 20a and cannot move relative to the motor shaft 20a in the axial direction, and the rotating shaft 311b supporting the driven sprocket 311a may be coupled to the input shaft 311 in a manner that is non-rotatable relative to the input shaft 311 and can move relative to the input shaft 311 in the axial direction. In other words, the drive sprocket 21a may be non-movable in the axial direction, and the driven sprocket 311a may move.

[0104] In this case, when the inner width of the power transmission chain 40 is set to A, the width of the driving sprocket 21a is set to B, the width of the driven sprocket 311a is set to C, the movable width of the driven sprocket 311a is set to D2, and the position deviation width of the driving sprocket 21a is set to E2, the contact between the power transmission chain 40 and the driven sprocket 311a can be avoided by setting the movable width D2 of the driven sprocket 311a in a manner that satisfies the following formula (3). Regarding this situation, the illustration is omitted.

[0105] D2>E2+C / 2+B / 2-A(3)

[0106] In addition, in this case, the structure can be such that a clamp 25 is fixed on the outer peripheral surface of the input shaft 311 passing through the inner peripheral portion of the rotating shaft 311b, and a sliding groove with a width wider than the width of the clamp 25 and capable of sliding the clamp 25 is provided on the inner peripheral portion of the rotating shaft 311b, and the rotating shaft 311b and the input shaft 311 can move relative to each other in the axial direction. The structure can also be such that a clamp 25 is fixed on the inner peripheral surface of the rotating shaft 311b, and a sliding groove with a width wider than the width of the clamp 25 and capable of sliding the clamp 25 is provided on the outer peripheral surface of the input shaft 311, and the rotating shaft 311b and the input shaft 311 can move relative to each other in the axial direction.

[0107] Furthermore, the drive shaft 21 supporting the drive sprocket 21a may be coupled to the motor shaft 20a in a manner that is non-rotatable relative to the motor shaft 20a and movable relative to the motor shaft 20a in the axial direction, and the rotating shaft 311b supporting the driven sprocket 311a may be coupled to the input shaft 311 in a manner that is non-rotatable relative to the input shaft 311 and movable relative to the input shaft 311 in the axial direction. In other words, the drive sprocket 21a may be movable in the axial direction, and the driven sprocket 311a may be movable.

[0108] Above, the embodiments of the present invention have been described with reference to the accompanying drawings, but the present invention is certainly not limited to the embodiments. Obviously, those skilled in the art can think of various variations or modifications within the scope of the technical solution, and it should be understood that these variations and modifications also belong to the technical scope of the present invention. In addition, the various constituent elements in the above-mentioned embodiments may also be arbitrarily combined within the scope of the gist of the invention.

[0109] For example, the power transmission chain 40 is exemplified as the endless flexible member, but the present invention is not limited thereto and may be a belt.

[0110] In this specification, at least the following matters are described. In addition, although the corresponding components and the like in the above-mentioned embodiment are shown in brackets, the present invention is not limited to these.

[0111] (1) A power transmission device (drive unit 10) comprising:

[0112] A first rotating member (driving sprocket 21a);

[0113] a first rotating shaft (driving shaft 21 ) supporting the first rotating member;

[0114] A second rotating member (driven sprocket 311a);

[0115] a second rotating shaft (rotating shaft 311 b ) that supports the second rotating member; and

[0116] An endless flexible member (power transmission chain 40) is wound around the first rotating member and the second rotating member.

[0117] in,

[0118] At least one of the first rotating member and the second rotating member is arranged to be movable in the axial direction.

[0119] The endless flexible member includes a restricting portion (a guide plate 410 ) that restricts movement of at least one of the first rotating member and the second rotating member in the axial direction.

[0120] According to (1), by enabling the first rotating member and / or the second rotating member to move axially, the axial position of the first rotating member and / or the second rotating member naturally follows the movement of the endlessly flexible member, thereby reducing the manufacturing cost without increasing the accuracy of each component.

[0121] (2) The power transmission device according to (1), wherein:

[0122] The first rotating member is fixed to the first rotating shaft in a manner that is non-rotatable relative to the first rotating shaft and non-movable relative to the first rotating shaft in the axial direction.

[0123] The second rotating member is fixed to the second rotating shaft so as to be non-rotatable relative to the second rotating shaft and non-movable relative to the second rotating shaft in the axial direction.

[0124] According to (2), the rotating shaft and the rotating member are fixed in both the axial direction and the circumferential direction, so whether the rotating shaft can move in the axial direction can be managed by the supporting method of the rotating shaft.

[0125] (3) The power transmission device according to (1), wherein:

[0126] The first rotating shaft is coupled to the output portion (motor shaft 20a) in a manner that it cannot rotate relative to the output portion on the drive source side but can move relative to the output portion in the axial direction, and a clip (clip 25) is fixed to either the first rotating shaft or the output portion.

[0127] A sliding groove (sliding groove 20b) for sliding the clip is provided on the other of the first rotating shaft and the output portion.

[0128] The width (width L2) of a slidable region defined by the first rotating shaft and the sliding groove is wider than the width (width L1) of the clip, whereby the first rotating shaft can move relative to the output portion in the axial direction.

[0129] According to (3), the amount of movement of the first rotating member in the axial direction can be managed by the relationship between the width of the clip and the width of the slidable region.

[0130] (4) The power transmission device according to (1), wherein:

[0131] The second rotating shaft is coupled to the input part (input shaft 311) on the driven part side so as to be non-rotatable relative to the input part and movable relative to the input part in the axial direction.

[0132] A clip (clip 25) is fixed to either the second rotating shaft or the input portion.

[0133] A sliding groove (sliding groove 20b) for sliding the clip is provided on the other of the second rotating shaft and the input portion.

[0134] The width (width L2) of a slidable region defined by the second rotation shaft and the slide groove is wider than the width (width L1) of the clip, whereby the second rotation shaft can move relative to the input portion in the axial direction.

[0135] According to (4), the amount of movement of the second rotating member in the axial direction can be managed by the relationship between the width of the clip and the width of the slidable region.

[0136] (5) The power transmission device according to (1), wherein:

[0137] The first rotating component is a driving sprocket,

[0138] The second rotating component is a driven sprocket,

[0139] The endless flexible component is a chain.

[0140] According to (5), it is applicable to a chain transmission.

[0141] (6) The power transmission device according to (5), wherein:

[0142] The limiting portion of the endless flexible member is a guide plate arranged on both side surfaces of the chain.

[0143] According to (6), the axial movement of the first rotating member and / or the second rotating member can be restricted by the guide plates arranged on both side surfaces of the chain.

[0144] (7) The power transmission device according to (6), wherein:

[0145] In the case where the driving sprocket can move in the axial direction and the driven sprocket cannot move in the axial direction,

[0146] When the width of the inner surface of the guide plate of the chain is set to A,

[0147] The width of the teeth of the drive sprocket is set to B,

[0148] The width of the teeth of the driven sprocket is set to C,

[0149] When the distance that the driving sprocket can move in the axial direction is D1 and the position deviation amount of the driven sprocket is E1,

[0150] The relationship is D1>E1+(B+C) / 2-A.

[0151] According to (7), the positional deviation of the driven sprocket can be absorbed by the amount of movement of the drive sprocket in the axial direction.

[0152] (8) The power transmission device according to (6), wherein:

[0153] In the case where the driving sprocket cannot move in the axial direction and the driven sprocket can move in the axial direction,

[0154] When the width of the inner surface of the guide plate of the chain is set to A,

[0155] The width of the teeth of the drive sprocket is set to B,

[0156] The width of the teeth of the driven sprocket is set to C,

[0157] The movable width of the driven sprocket along the axial direction is set to D2,

[0158] When the position deviation of the driving sprocket is set to E2,

[0159] The relationship is D2>E2+(B+C) / 2-A.

[0160] According to (8), the positional deviation of the driving sprocket can be absorbed by the amount of movement of the driven sprocket in the axial direction.

[0161] (9) The power transmission device according to (6), wherein:

[0162] The guide plate has a guide portion (guide portion 411 ) that overlaps with the teeth of the drive sprocket and the teeth of the driven sprocket when viewed from the axial direction.

[0163] According to (9), the axial movement of the first rotating member and / or the second rotating member can be restricted by the guide portion of the guide plate.

Claims

1. A power transmission device comprising: a first rotating member; a first rotating shaft supporting the first rotating member; a second rotating member; a second rotating shaft supporting the second rotating member; and an endless flexible member, which is wound around the first rotating member and the second rotating member, in, At least one of the first rotating member and the second rotating member is arranged to be movable in the axial direction. The endless flexible member includes a restriction portion that restricts movement of at least one of the first rotating member and the second rotating member in the axial direction.

2. The power transmission device according to claim 1, wherein: The first rotating member is fixed to the first rotating shaft in a manner that is non-rotatable relative to the first rotating shaft and non-movable relative to the first rotating shaft in the axial direction. The second rotating member is fixed to the second rotating shaft so as to be non-rotatable relative to the second rotating shaft and non-movable relative to the second rotating shaft in the axial direction.

3. The power transmission device according to claim 1, wherein: The first rotating shaft is coupled to the output portion in a manner that it cannot rotate relative to the output portion on the driving source side and can move relative to the output portion in the axial direction. A clip is fixed to either the first rotating shaft or the output portion. A sliding groove for sliding the clip is provided on the other of the first rotating shaft and the output portion. The width of a slidable region defined by the first rotating shaft and the sliding groove is wider than a width of the clip, whereby the first rotating shaft can move relative to the output portion in the axial direction.

4. The power transmission device according to claim 1, wherein: The second rotating shaft is coupled to the input part in a manner that it cannot rotate relative to the input part on the driven part side and is movable relative to the input part in the axial direction. A clip is fixed to either the second rotating shaft or the input portion. A sliding groove for sliding the clip is provided on the other of the second rotating shaft and the input portion. The width of a slidable region defined by the second rotation shaft and the slide groove is wider than a width of the clip, whereby the second rotation shaft can move relative to the input portion in the axial direction.

5. The power transmission device according to claim 1, wherein: The first rotating component is a driving sprocket, The second rotating component is a driven sprocket, The endless flexible component is a chain.

6. The power transmission device according to claim 5, wherein: The limiting portion of the endless flexible member is a guide plate arranged on both side surfaces of the chain.

7. The power transmission device according to claim 6, wherein: In the case where the driving sprocket can move in the axial direction and the driven sprocket cannot move in the axial direction, When the width of the inner surface of the guide plate of the chain is set to A, The width of the teeth of the drive sprocket is set to B, The width of the teeth of the driven sprocket is set to C, The distance that the driving sprocket can move along the axial direction is set to D1, When the position deviation of the driven sprocket is set to E1, The relationship is D1>E1+(B+C) / 2-A.

8. The power transmission device according to claim 6, wherein: In the case where the driving sprocket cannot move in the axial direction and the driven sprocket can move in the axial direction, When the width of the inner surface of the guide plate of the chain is set to A, The width of the teeth of the drive sprocket is set to B, The width of the teeth of the driven sprocket is set to C, The movable width of the driven sprocket along the axial direction is set to D2, When the position deviation of the driving sprocket is set to E2, The relationship is D2>E2+(B+C) / 2-A.

9. The power transmission device according to claim 6, wherein: The guide plate has a guide portion that overlaps with the teeth of the drive sprocket and the teeth of the driven sprocket when viewed from the axial direction.

Images