Power transmission device

Abstract

To suppress manufacturing cost of each component without increasing the degree of precision thereof.SOLUTION: A driven unit 10 includes a drive sprocket 21a, a drive shaft 21 supporting a drive sprocket 21a, a driven sprocket 311a, a rotation shaft 311b supporting a driven sprocket 311a, and a power transmission chain 40 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 movably in an axial direction. The power transmission chain 40 has a guide plate 410 for restricting the movement of at least one of the drive sprocket 21a and the driven sprocket 311a in the axial direction.SELECTED DRAWING: Figure 7

Description

[Technical field]

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

[0002] 2. Description of the Related Art Power transmission devices have been known in the past, in which an endless flexible member such as a chain or a belt is wound around a drive sprocket and a driven sprocket to transmit power via the endless flexible member (see, for example, Patent Documents 1 to 3).

[0003] In such power transmission devices, the drive sprocket and the driven sprocket are generally positioned in the axial direction with high accuracy, and the amount of variation in the axial direction is kept within the width of the endless flexible member. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2007-154913 A [Patent Document 2] JP 2011-236943 A [Patent Document 3] JP 2016-61337 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in order to position the drive sprocket and driven sprocket in the axial direction with high precision, the parts that support them also need to be formed with high precision, which is one of the factors that increase manufacturing costs.

[0006] The present invention provides a power transmission device that can reduce manufacturing costs. [Means for solving the problem]

[0007] The present invention relates to 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; A power transmission device comprising: an endless flexible member wound around the first rotating member and the second rotating member, At least one of the first rotating member and the second rotating member is provided to be movable in an axial direction, The endless flexible member has a restricting portion that restricts movement of at least one of the first rotating member and the second rotating member in the axial direction. Effect of the Invention

[0008] According to the present invention, it is possible to reduce manufacturing costs without increasing the precision of each component. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of a vehicle equipped with a drive unit 10 according to an embodiment of the present invention, viewed from the left. [Diagram 2] FIG. 1 is a perspective view showing a drive unit 10 according to an embodiment of the present invention with a part cut away. [Diagram 3] 3 is a partially cutaway perspective view for explaining a power transmission path in the drive unit 10 of FIG. 2. FIG. [Figure 4] 3 is a skeleton diagram of a reduction gear in the drive unit 10 of FIG. 2. [Diagram 5] 3 is a cross-sectional view illustrating a support structure for a drive shaft 21. FIG. [Figure 6] 2 is an exploded perspective view of a portion of the power transmission chain 40. FIG. [Figure 7] FIG. 2 is a cross-sectional perspective view of the chain transmission mechanism 4. [Figure 8] 10 is an explanatory diagram illustrating a movable width D of a drive shaft 21. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] A vehicle equipped with a drive unit according to an embodiment of the present invention will be described below with reference to the accompanying drawings. The drawings are to be viewed according to the direction of the reference symbols. In this specification and the like, for the sake of simplicity and clarity, the front / rear, left / right, and up / down directions are described according to the direction as seen by the driver of the vehicle, and in the drawings, the front of the vehicle is indicated as Fr, the rear as Rr, the left as L, the right as R, the top as U, and the bottom as D.

[0011] [Overall vehicle configuration] As shown in Fig. 1, a vehicle V of this embodiment has a pair of left and right front wheels FW, a pair of left and right rear wheels RW, and a floor panel FP that constitutes the floor of the vehicle V. The vehicle V is partitioned into a passenger compartment CB and a front room FRM in front of the passenger compartment CB by a dash panel DP that extends in the vertical direction above the floor panel FP. A front seat FS and a rear seat RS are provided in the passenger compartment CB.

[0012] The vehicle V includes a drive unit 10 serving as a drive source, and a battery pack IPU that stores electric power to be supplied to the drive unit 10.

[0013] The drive unit 10 is disposed behind the rear seat RS and below the floor panel FP. The battery pack IPU is disposed under the floor of the vehicle compartment CB below the floor panel FP. The battery pack IPU houses a plurality of battery modules, each of which has a plurality of stacked battery cells. Each battery cell is a chargeable and dischargeable secondary battery, such as a lithium-ion battery or an all-solid-state battery.

[0014] [Overall configuration of drive unit] As shown in Figures 2 and 3, the drive unit 10 includes a drive motor 20, a reduction gear 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 gear 30, a control device 50 that controls the drive motor 20, and a drive unit case 11 that houses these.

[0015] The drive unit case 11 has a main case 111 , a left side cover 112 that covers the left side surface of the main case 111 , and a right side cover 113 that covers the right side surface of the main case 111 .

[0016] The drive unit case 11 has a motor chamber 12 that houses the drive motor 20, a gear chamber 13 that houses the reduction gear 30, a chain chamber 14 that houses the chain transmission mechanism 4, and a controller chamber 15 that houses the control device 50. The motor chamber 12 and the gear chamber 13 are formed side by side in the front-to-rear direction, with the motor chamber 12 at the front and the gear chamber 13 at 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 case 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 the main case 111 and a right side cover 113.

[0017] The drive motor 20 is a so-called inner rotor type motor that includes a motor shaft 20a, a rotor 22 that is attached to the motor shaft 20a and rotates integrally with the motor shaft 20a, and a stator 23 that is arranged radially opposite the rotor 22 with a small gap between them on the radial outside of the rotor 22.

[0018] In this embodiment, in the drive unit 10, the drive motor 20 is arranged so that the axial direction (i.e., the motor shaft 20a) faces horizontally in the left-right direction. By arranging the motor shaft 20a to face horizontally in this way, the vertical dimension of the drive unit 10 can be made compact. In the following description, the extension direction of the motor shaft 20a is referred to as the axial direction.

[0019] The stator 23 includes a stator core 231 and a coil 232 attached to the stator core 231 and configured with a plurality of windings of U-phase, V-phase, and W-phase.

[0020] A drive shaft 21 is coupled to the motor shaft 20a. The drive shaft 21 is coupled to the motor shaft 20a so as to be non-rotatable relative to the motor shaft 20a and movable relative to the motor shaft 20a in the axial direction. More specifically, as shown in FIG. 5, a clip 25 (e.g., a C-shaped clip) is fitted in a clip groove 21b on the outer circumferential surface of one end 21R (the right end in this embodiment) of the drive shaft 21 that passes through the inner circumferential portion of the motor shaft 20a and is immovable relative to the motor shaft 20a. On the other hand, a slide groove 20b is provided on the inner circumferential portion of the motor shaft 20a, in which the clip 25 fixed to the drive shaft 21 can slide. Here, a width L2 of a slidable area defined by the drive shaft 21 and the slide groove 20b of the motor shaft 20a is wider than a width L1 of the clip 25.

[0021] The other end 21L (the left end in this embodiment) of the drive shaft 21 is rotatably supported by a cylindrical roller bearing (roller bearing) 77 provided on the inner circumferential surface of a front boss portion 112f (see FIG. 2) of the left side cover 112. The cylindrical roller bearing 77 has a small support force against an axial load, like a ball bearing or a tapered roller bearing. Therefore, the drive shaft 21 is allowed to move in the axial direction relative to the motor shaft 20a and the left side cover 112 within the range of the width L2 of the slidable area. Since the drive shaft 21 rotates integrally with the motor shaft 20a, in the following description, the drive shaft 21 may be referred to as the drive shaft 21 of the drive motor 20.

[0022] A 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 so as to be unrotatable and unmovable in the axial direction relative to the drive shaft 21. In other words, the drive sprocket 21a is provided so as to be axially movable relative to the motor shaft 20a and the drive unit case 11, and rotates integrally with the drive shaft 21.

[0023] The chain transmission mechanism 4 includes a drive sprocket 21a attached to the drive shaft 21, a driven sprocket 311a attached to an input shaft 311 of a planetary gear mechanism 31 (described later) on the same plane as the drive sprocket 21a, and a power transmission chain 40 wound around the drive sprocket 21a and the driven sprocket 311a. The driven sprocket 311a has a larger diameter than the drive sprocket 21a, and the number of teeth of the driven sprocket 311a is greater than the number of teeth of the drive sprocket 21a.

[0024] As shown in FIGS. 3 and 4, the reduction gear 30 includes a planetary gear mechanism 31 and a differential gear mechanism 32.

[0025] The planetary gear mechanism 31 has an input shaft 311 , a sun gear 312 , a plurality of planetary pinion shafts 313 , the same number of stepped pinions 314 as the planetary pinion shafts 313 , a planetary carrier 316 , and a ring gear 317 .

[0026] In this embodiment, the planetary gear mechanism 31 is arranged side by side in the front-rear direction behind the drive motor 20. The planetary gear mechanism 31 is arranged so that its axial direction (i.e., the input shaft 311) faces in the left-right direction parallel to the axial direction of the drive motor 20. The input shaft 311 of the planetary gear mechanism 31 is also arranged at a position at approximately the same height in the up-down direction as the drive shaft 21 of the drive motor 20. Furthermore, the outer diameter dimension of the planetary gear mechanism 31 is approximately the same as the outer diameter dimension of the drive motor 20, and the height of the drive unit 10 in the up-down direction is reduced.

[0027] The input shaft 311 is a hollow shaft, and a left drive shaft 325L described later is inserted inside. A rotating shaft 311b of a driven sprocket 311a, around which a power transmission chain 40 of a chain transmission mechanism 4 is wound, is fixed to the left end of the input shaft 311 so as to be non-rotatable and non-movable in the axial direction. The driven sprocket 311a is fixed to the rotating shaft 311b so as to be non-rotatable and non-movable in the axial direction. That is, the driven sprocket 311a is provided so as to be non-movable in the axial direction with respect to the input shaft 311 and the drive unit case 11, and rotates integrally with the input shaft 311. In this embodiment, the driven sprocket 311a and the rotating shaft 311b are molded integrally, but this is not limited thereto, and the driven sprocket 311a may be formed separately from the rotating shaft 311b as long as the driven sprocket 311a is fixed to the rotating shaft 311b so as to be non-rotatable and non-movable in the axial direction.

[0028] 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.

[0029] The multiple planetary pinion shafts 313 are arranged at equal intervals in the circumferential direction along the outer circumferential surface of sun gear 312 so as to face in the left-right direction in parallel with input shaft 311 on the radially outer side of sun gear 312 .

[0030] A stepped pinion 314 having a first planetary gear 314a and a second planetary gear 314b that rotate integrally with the planetary pinion shaft 313 is rotatably supported on each of the planetary pinion shafts 313.

[0031] First planetary gear 314 a is an external gear that is disposed on the outer circumferential surface of sun gear 312 and meshes with sun gear 312 .

[0032] The second planetary gear 314 b is an external gear that is disposed on the inner circumferential surface of the ring gear 317 and meshes with the ring gear 317 .

[0033] The planetary carrier 316 is connected to the planetary pinion shaft 313. The planetary carrier 316 is integral with the planetary pinion shaft 313 and is rotatable about a rotation axis coaxial with the input shaft 311 (and the sun gear 312).

[0034] Therefore, the stepped pinion 314 having the first planetary gear 314a and the second planetary gear 314b can rotate about the planetary pinion shaft 313 and can revolve together with the planetary pinion shaft 313 on a rotation axis coaxial with the input shaft 311 (and the sun gear 312). The planetary carrier 316 rotates together with the orbital motion of the stepped pinion 314 on a rotation axis coaxial with the input shaft 311 (and the sun gear 312).

[0035] The ring gear 317 is an annular internal gear whose inner circumferential surface meshes with each of the second planetary gears 314b. In this embodiment, the ring gear 317 is fixed to the drive unit case 11, and the ring gear 317 itself does not rotate.

[0036] 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 rotatably supported on the differential pinion shaft 322, a left side gear 324L and a right side gear 324R meshing with the first bevel gear 323a and the second bevel gear 323b, and a left drive shaft 325L and a right drive shaft 325R.

[0037] The differential case 321 is formed integrally with the planetary carrier 316 of the planetary gear mechanism 31. Therefore, the differential case 321 rotates integrally with the planetary carrier 316 of the planetary gear mechanism 31 on a rotation axis coaxial with the input shaft 311.

[0038] Next, a power transmission path of the power output from the drive motor 20 will be described.

[0039] Power generated by the driving motor 20 is output from the motor shaft 20a, and the drive shaft 21 and the drive sprocket 21a attached to the drive shaft 21 rotate together with the motor shaft 20a. When the drive sprocket 21a rotates, the driven sprocket 311a rotates by the power transmission chain 40 wound around the drive sprocket 21a and the driven sprocket 311a attached to the input shaft 311 of the planetary gear mechanism 31. The input shaft 311 of the planetary gear mechanism 31 rotates together with the driven sprocket 311a. At this time, since the number of teeth of the driven sprocket 311a is greater than the number of teeth of the drive sprocket 21a, the rotation of the drive shaft 21 is decelerated through the drive 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.

[0040] In the planetary gear mechanism 31, power input to the input shaft 311 is transmitted to the stepped pinion 314 via the sun gear 312. The stepped pinion 314 rotates and revolves around its axis. The planetary carrier 316 rotates integrally with the revolution 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 reduced in speed at a predetermined reduction ratio and transmitted to the planetary carrier 316.

[0041] 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 therefore 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 at a predetermined reduction ratio and input to the differential case 321 via the planetary carrier 316.

[0042] 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 around the rotation axis of the differential case 321.

[0043] When the vehicle V is moving straight, there is no difference in rotation 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 response to the rotation of the differential pinion shaft 322. The left drive shaft 325L rotates together with the rotation of the left side gear 324L, causing the left rear wheel RW to rotate, and the right drive shaft 325R rotates together with the rotation of the right side gear 324R, causing the right rear wheel RW to rotate.

[0044] When the vehicle V is turning, the differential pinion shaft 322 revolves and the first bevel gear 323a and the second bevel gear 323b rotate so that the rotation speed of the rear wheel RW on the inside of the turn slows down and the rotation speed of the rear wheel RW on the outside of the turn increases, while 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 so that the rotation speed of the rear wheel RW on the inside of the turn slows down and the rotation speed of the rear wheel RW on the outside of the turn increases. Then, the left drive shaft 325L rotates together with the rotation of the left side gear 324L to rotate the left rear wheel RW, and the right drive shaft 325R rotates together with the rotation of the right side gear 324R to rotate the right rear wheel RW. Therefore, when the vehicle V is turning, the left drive shaft 325L and the right drive shaft 325R rotate so that the rotational speed of the rear wheel RW on the inside of the turn slows down and the rotational speed of the rear wheel RW on the outside of the turn increases.

[0045] In this manner, as shown by the arrows in FIG. 3, the power output from the drive motor 20 is decelerated via the drive sprocket 21a, the driven sprocket 311a, and the power transmission chain 40, and input to the reduction gear 30, where it is 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.

[0046] Next, the structure of the power transmission chain 40 will be described with reference to FIGS. In the power transmission chain 40, a plurality of ring plates 401 are arranged in a circular manner in the traveling direction, and are arranged in a plurality of rows in the axial direction, and the ring plates 401 arranged in a circular manner in the plurality of rows are connected by pins 403 penetrating in the axial direction. More specifically, each ring plate 401 is formed with two through holes 401a and 401b penetrating in the axial direction so as to be aligned in the traveling direction, and the pins 403 penetrate the through holes 401a and 401b different from those of the ring plates 401 in the rows adjacent in the axial direction. That is, when one pin 403 is focused on, the pin 403 penetrates the through hole 401a of the ring plate 401 and the through hole 401b of the ring plate 401 alternately along the axial direction. The pins 403 are arranged in all the through holes 401a and 401b.

[0047] As a result, the ring plates 401 arranged in a ring shape are connected in both the axial direction and the traveling direction to form an endless ring. Groove portions 401c that mesh with the teeth of the sprockets 21a and 311a are formed between the through holes 401a and 401b in each ring plate 401. As a result, the rotation of the drive sprocket 21a is transmitted to the driven sprocket 311a via the power transmission chain 40.

[0048] The pins 403 protrude on both axial sides from the ring plate 401 on one axial end side and the ring plate 401 on the other axial end side.

[0049] A pair of left and right guide plates 410 are arranged on the outside of the ring plate 401 on one axial end side and the ring plate 401 on the other axial end side. The guide plates 410 are formed so that through holes 410a, 410b are aligned in the direction of travel, and the protruding portion of the pin 403 is press-fitted into them.

[0050] The guide plate 410 has guide portions 411 that overlap with the teeth of the sprockets 21a, 311a when viewed in the axial direction. That is, the guide plate 410 does not have the groove portions 401c of the ring plate 401 formed therein.

[0051] 7, a distance L3 between the pair of left and right guide plates 410 is longer than an axial length L4 of the sprockets 21a, 311a. That is, the sprockets 21a, 311a and the power transmission chain 40 are configured to be relatively movable in the axial direction.

[0052] As described above, in this embodiment, since the drive shaft 21 is allowed to move in the axial direction, there is no need to set the positional accuracy of the drive shaft 21 and the input shaft 311 to high accuracy. That is, a thrust load (axial load) is input to the driven sprocket 311a supported by the input shaft 311 due to meshing between the sun gear 312 and the first planetary gear 314a of the stepped pinion 314. In contrast, since there is no reduction mechanism between the drive motor 20 and the drive sprocket 21a, no thrust load is applied. Therefore, it is possible to provide the drive shaft 21 with a degree of freedom in the axial direction.

[0053] By utilizing this, the drive shaft 21 is supported so as to allow its axial movement, so that even if there is variation in the axial position of the driven sprocket 311a, the guide plate 410 of the power transmission chain 40 comes into contact with the outer end face of the sprocket 21a, and the sprocket 21a can move in accordance with the oscillation of the power transmission chain 40. In this way, in the drive unit 10, the movement of the drive shaft 21 can absorb variation in the axial direction, so there is no need to manage the drive shaft 21 and the input shaft 311 with high precision.

[0054] Next, the movable width of drive shaft 21 (hereinafter referred to as the movable width of drive sprocket 21a) will be described with reference to FIG.

[0055] Figure 8 shows a chain transmission mechanism 4 in which the drive sprocket 21a is movable in the axial direction and the driven sprocket 311a is immovable in the axial direction. The upper diagram shows the positional relationship when there is no axial positional variation in the driven sprocket 311a, and the lower diagram shows the positional relationship when there is a degree of axial positional variation in the driven sprocket 311a.

[0056] In Figure 8, the DR axis indicates the axis of the drive sprocket 21a (drive shaft 21), the DN axis indicates the axis of the driven sprocket 311a (input shaft 311), and the reference position is a reference line passing through the axial center of the drive sprocket 21a and the axial center of the driven sprocket 311a when there is no axial positional variation in the driven sprocket 311a.

[0057] If the inner width of the power transmission chain 40 is A, the width of the drive sprocket 21a is B, the width of the driven sprocket 311a is C, the movable width of the drive sprocket 21a is D1, and the positional variation width of the driven sprocket 311a is E1, then the movable width D of the drive sprocket 21a is expressed by the following equation (1), as shown in Figure 8.

[0058] D1=E1+C / 2+B / 2-A (1)

[0059] That is, in the drive unit 10, the positional variation width E1 of the driven sprocket 311a can be tolerated, and in that case, the drive sprocket 21a can be set to move by the movable width D1. In other words, if the support structure of the drive sprocket 21a (drive shaft 21) is given the movable width D1, the support structure of the driven sprocket 311a (input shaft 311) can be tolerated by the positional variation width E1.

[0060] In addition, even if there is a positional variation width E1 of the driven sprocket 311a, the movable width D1 of the drive sprocket 21a to prevent the power transmission chain 40 and the drive sprocket 21a from interfering with each other in the axial direction is expressed by the following equation (2).

[0061] D1>E1+C / 2+B / 2-A (2)

[0062] By setting the movable width D1 of the drive sprocket 21a so as to satisfy the above formula (2), it is possible to avoid contact between the power transmission chain 40 and the drive sprocket 21a.

[0063] In the above embodiment, the clip 25 is fixed to the outer peripheral surface of the drive shaft 21 that passes through the inner peripheral portion of the motor shaft 20a, and the inner peripheral portion of the motor shaft 20a is provided with a sliding groove 20b along which the clip 25 can slide, allowing the motor shaft 20a and the drive shaft 21 to move relatively in the axial direction, but this is not limited to the above. That is, the clip 25 may be fixed to the inner peripheral surface of the motor shaft 20a, and the outer peripheral surface of the drive shaft 21 may be provided with a sliding groove along which the clip 25 can slide, allowing the motor shaft 20a and the drive shaft 21 to move relatively in the axial direction.

[0064] In the above embodiment, the drive shaft 21 supporting the drive sprocket 21a is connected to the motor shaft 20a so as to be non-rotatable relative to the motor shaft 20a and to be movable in the axial direction, and the rotating shaft 311b supporting the driven sprocket 311a is connected to the input shaft 311 so as to be non-rotatable relative to the motor shaft 20a and to be movable in the axial direction. In other words, the drive sprocket 21a is movable in the axial direction, and the driven sprocket 311a is immovable. However, the present invention is not limited to this, and the drive shaft 21 supporting the drive sprocket 21a may be connected to the motor shaft 20a so as to be non-rotatable relative to the motor shaft 20a and to be immovable in the axial direction, and the rotating shaft 311b supporting the driven sprocket 311a may be connected to the input shaft 311 so as to be non-rotatable relative to the motor shaft 20a and to be movable in the axial direction. In other words, the drive sprocket 21a may be immovable in the axial direction, and the driven sprocket 311a may be movable.

[0065] In this case, although not shown in the figure, if the inner width of the power transmission chain 40 is A, the width of the drive sprocket 21a is B, the width of the driven sprocket 311a is C, the movable width of the driven sprocket 311a is D2, and the positional variation width of the drive sprocket 21a is E2, 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 to satisfy the following equation (3).

[0066] D2>E2+C / 2+B / 2-A (3)

[0067] In this case, clip 25 may be fixed to the outer peripheral surface of input shaft 311, which passes through the inner peripheral portion of rotating shaft 311b, and a sliding groove having a width wider than the width of clip 25, through which clip 25 can slide, may be provided on the inner peripheral portion of rotating shaft 311b, so that rotating shaft 311b and input shaft 311 can move relative to each other in the axial direction; alternatively, clip 25 may be fixed to the inner peripheral surface of rotating shaft 311b, and a sliding groove having a width wider than the width of clip 25, through which clip 25 can slide, may be provided on the outer peripheral surface of input shaft 311, so that rotating shaft 311b and input shaft 311 can move relative to each other in the axial direction.

[0068] Furthermore, the drive shaft 21 supporting the drive sprocket 21a may be coupled to the motor shaft 20a so as to be non-rotatable relative to the motor shaft 20a but movable axially relative to the motor shaft 20a, and the rotating shaft 311b supporting the driven sprocket 311a may be coupled to the input shaft 311 so as to be non-rotatable relative to the motor shaft 20a but movable axially relative to the motor shaft 20a. In other words, the drive sprocket 21a may be movable axially, and the driven sprocket 311a may be movable.

[0069] Although the embodiment of the present invention has been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such an embodiment. It is clear that a person skilled in the art can come up with various modified or amended examples within the scope of the claims, and it is understood that these also naturally belong to the technical scope of the present invention. In addition, the components in the above embodiment may be arbitrarily combined within the scope of the invention.

[0070] For example, although the power transmission chain 40 is exemplified as an endless flexible member, the present invention is not limited to this and may be a belt.

[0071] This specification describes at least the following items. Note that, in parentheses, components corresponding to those in the above-mentioned embodiment are shown, but the present invention is not limited to these.

[0072] (1) a first rotating member (drive sprocket 21a); A first rotating shaft (drive shaft 21) that supports the first rotating member; A second rotating member (driven sprocket 311a), A second rotating shaft (rotating shaft 311b) that supports the second rotating member; A power transmission device (drive unit 10) including an endless flexible member (power transmission chain 40) wound around the first rotating member and the second rotating member, At least one of the first rotating member and the second rotating member is provided to be movable in an axial direction, The endless flexible member has a restricting portion (guide plate 410) that restricts movement of at least one of the first rotating member and the second rotating member in the axial direction.

[0073] 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 endless flexible member, thereby making it possible to reduce manufacturing costs without increasing the accuracy of each component.

[0074] (2) A power transmission device according to (1), the first rotating member is fixed to the first rotating shaft so as to be unable to rotate relative to the first rotating shaft and to be unable to move 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 unrotatable relative to the second rotating shaft and unmovable relative to the second rotating shaft in the axial direction, in this power transmission device.

[0075] According to (2), since the rotating shaft and the rotating member are fixed both in the axial and circumferential directions, the possibility of axial movement can be controlled by the method of supporting the rotating shaft.

[0076] (3) A power transmission device according to (1), The first rotating shaft is coupled to an output portion (motor shaft 20a) on the driving source side so as to be non-rotatable relative to the output portion and to be movable relative to the output portion in the axial direction. A clip (clip 25) is fixed to either the first rotating shaft or the output portion, The other of the first rotating shaft and the output portion is provided with a slide groove (slide groove 20b) along which the clip slides, A power transmission device in which the width (width L2) of the sliding area defined by the first rotating shaft and the sliding groove is wider than the width (width L1) of the clip, thereby allowing the first rotating shaft to move relative to the output section in the axial direction.

[0077] According to (3), the amount of axial movement of the first rotating member can be controlled by the relationship between the width of the clip and the width of the slidable area.

[0078] (4) A power transmission device according to (1), The second rotating shaft is coupled to an input portion (input shaft 311) on the driven portion side so as to be non-rotatable relative to the input portion and to be movable relative to the input portion in the axial direction. A clip (clip 25) is fixed to either the second rotation shaft or the input portion, The other of the second rotation shaft and the input portion is provided with a slide groove (slide groove 20b) along which the clip slides, A power transmission device in which the width (width L2) of the sliding area defined by the second rotating shaft and the sliding groove is wider than the width (width L1) of the clip, thereby allowing the second rotating shaft to move relative to the input portion in the axial direction.

[0079] According to (4), the amount of axial movement of the second rotating member can be controlled by the relationship between the width of the clip and the width of the slidable area.

[0080] (5) A power transmission device according to (1), the first rotating member is a drive sprocket; the second rotating member is a driven sprocket, The power transmission device, wherein the endless flexible member is a chain.

[0081] According to (5), it can be applied to a chain transmission.

[0082] (6) The power transmission device according to (5), A power transmission device, wherein the regulating portion of the endless flexible member is a guide plate arranged on both sides of the chain.

[0083] 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 sides of the chain.

[0084] (7) A power transmission device according to (6), When the drive sprocket is movable in the axial direction and the driven sprocket is immovable in the axial direction, The width of the inner surface of the guide plate of the chain is A, The width of the teeth of the drive sprocket is B, The width of the teeth of the driven sprocket is C, The distance that the drive sprocket can move in the axial direction is D1. When the positional variation of the driven sprocket is E1, D1>E1+(B+C) / 2-A A power transmission device having the following relationship.

[0085] According to (7), positional variation of the driven sprocket can be absorbed by the amount of axial movement of the drive sprocket.

[0086] (8) A power transmission device according to (6), When the drive sprocket cannot move in the axial direction and the driven sprocket can move in the axial direction, The width of the inner surface of the guide plate of the chain is A, The width of the teeth of the drive sprocket is B, The width of the teeth of the driven sprocket is C, The movable width of the driven sprocket in the axial direction is D2, When the positional variation of the drive sprocket is E2, D2>E2+(B+C) / 2-A A power transmission device having the following relationship.

[0087] According to (8), the positional variation of the drive sprocket can be absorbed by the axial movement of the driven sprocket.

[0088] (9) The power transmission device according to (6), The power transmission device, wherein the guide plate has a guide portion (guide portion 411) that overlaps with teeth of the drive sprocket and teeth of the driven sprocket when viewed in the axial direction.

[0089] 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. [Explanation of symbols]

[0090] 10 Drive unit (power transmission device) 20a Motor shaft (output section) 20b Sliding groove 21 Drive shaft (first rotating shaft) 21a Drive sprocket (first rotating member) 25 clips 40 Power transmission chain (endless flexible member) 311 Input shaft (input part) 311a Driven sprocket (second rotating member) 311b Rotation axis (second rotation axis) 410 Guide plate (regulating part) 411 Guide part L1 width L2 width

Claims

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

2. 2. The power transmission device according to claim 1, The first rotating member is fixed to the first rotating shaft so as to be unable to rotate relative to the first rotating shaft and to be unable to move 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 unrotatable relative to the second rotating shaft and unmovable relative to the second rotating shaft in the axial direction.

3. 2. The power transmission device according to claim 1, The first rotating shaft is coupled to an output portion on a drive source side so as to be non-rotatable relative to the output portion and to be movable relative to the output portion in the axial direction. A clip is fixed to either the first rotation shaft or the output portion, The other of the first rotating shaft and the output portion is provided with a slide groove along which the clip slides, A power transmission device in which a width of a slidable area defined by the first rotating shaft and the sliding groove is wider than a width of the clip, such that the first rotating shaft is movable relative to the output portion in the axial direction.

4. 2. The power transmission device according to claim 1, The second rotating shaft is coupled to an input portion on a driven portion side so as to be non-rotatable relative to the input portion and to be movable relative to the input portion in the axial direction. a clip is fixed to either the second rotation shaft or the input portion, The other of the second rotation shaft and the input portion is provided with a slide groove along which the clip slides, A power transmission device in which a width of a slidable area defined by the second rotating shaft and the sliding groove is wider than a width of the clip, such that the second rotating shaft is movable relative to the input portion in the axial direction.

5. 2. The power transmission device according to claim 1, the first rotating member is a drive sprocket; the second rotating member is a driven sprocket, The power transmission device, wherein the endless flexible member is a chain.

6. 6. The power transmission device according to claim 5, A power transmission device, wherein the regulating portion of the endless flexible member is a guide plate arranged on both sides of the chain.

7. 7. The power transmission device according to claim 6, When the drive sprocket is movable in the axial direction and the driven sprocket is immovable in the axial direction, The width of the inner surface of the guide plate of the chain is A, The width of the teeth of the drive sprocket is B, The width of the teeth of the driven sprocket is C, The distance that the drive sprocket can move in the axial direction is D1. When the amount of positional variation of the driven sprocket is E1, D1>E1+(B+C) / 2-A A power transmission device having the following relationship.

8. 7. The power transmission device according to claim 6, When the drive sprocket cannot move in the axial direction and the driven sprocket can move in the axial direction, The width of the inner surface of the guide plate of the chain is A, The width of the teeth of the drive sprocket is B, The width of the teeth of the driven sprocket is C, The movable width of the driven sprocket in the axial direction is D2, When the positional variation of the drive sprocket is E2, D2>E2+(B+C) / 2-A A power transmission device having the following relationship.

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

Images