Power transmission device

Abstract

Provided is a power transmission device having a high degree of freedom in layout. A drive unit (10) is provided with a drive motor (20), a chain transmission mechanism (4), a drive unit case (11), a drive sprocket (21a) disposed on a drive shaft (21) of the drive motor (20), a driven sprocket (311a), a power transmission chain (40) wound around the drive sprocket (21a) and the driven sprocket (311a), and a parking gear (61) disposed on the drive shaft (21) of the drive motor (20).

Description

Technical Field

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

[0002] In the past, there is a known power transmission device having a transmission part that winds an endless flexible member such as a chain or a belt around a driving sprocket and a driven sprocket and transmits power via the endless flexible member. In such a power transmission device, it is necessary to set a parking mechanism to avoid the track of the endless flexible member.

[0003] For example, in the remote video head swing mechanism described in Patent Document 1, the following mechanism is arranged inside the chain belt: the mechanism includes a first gear that is always meshed with the sprocket and a second gear that is always meshed with the first gear, and the drive is stopped by interlocking (interlocking) by meshing the second gear with the sprocket when the first gear is meshed with the second gear.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 10-148241 Summary of the invention

[0007] Problems to be solved by the invention

[0008] For example, in order to ensure as wide a space as possible inside the vehicle cabin, it is desired to downsize a power transmission device used in an electric vehicle or the like. Therefore, there is a demand for greater freedom in the arrangement of a parking mechanism.

[0009] The present invention provides a power transmission device with a high degree of layout freedom.

[0010] Solutions to Solve Problems

[0011] The present invention provides a power transmission device, comprising:

[0012] Driving source;

[0013] a transmission unit that changes the speed of the power of the driving source and transmits the power to the driven part; and

[0014] a housing that accommodates the drive source and the speed change unit,

[0015] in,

[0016] The power transmission device further comprises:

[0017] a driving sprocket, which is arranged on the output shaft of the driving source;

[0018] A driven sprocket, which is arranged on the same plane as the driving sprocket;

[0019] an endless flexible member wound around the driving sprocket and the driven sprocket; and

[0020] A parking gear is arranged on the output shaft of the driving source.

[0021] Effects of the Invention

[0022] According to the present invention, the degree of freedom in layout of the parking gear is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] 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.

[0024] 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.

[0025] Figure 3 It is used to illustrate Figure 2 A partially cutaway stereoscopic view of a power transmission path in the drive unit 10.

[0026] Figure 4 yes Figure 2 A skeleton diagram of the reduction device in the drive unit 10.

[0027] Figure 5 It is a perspective view showing the internal structure of the chain chamber 14 .

[0028] Figure 6 It is a side view schematically showing a part of the chain transmission mechanism 4 and the parking mechanism 6 .

[0029] Figure 7 It is a plan view schematically showing a part of the chain transmission mechanism 4 and the parking mechanism 6 .

[0030] Figure 8 It is a schematic diagram of the chain transmission mechanism 4 for explaining an example of arrangement conditions of the control shaft 65 .

[0031] Fig. 9 It is a schematic diagram of the chain transmission mechanism 4 for explaining another example of the arrangement condition of the control shaft 65 .

[0032] Fig.10 It is calculated Fig. 9 FIG. 1 is an explanatory diagram of a calculation formula for the radius of the arc L3 shown.

[0033] Description of reference numerals:

[0034] 4 Chain transmission mechanism (speed change part)

[0035] 10 Drive unit (power transmission device)

[0036] 11 drive unit housing (housing)

[0037] 20 driving motor (driving source)

[0038] 21 drive shaft (output shaft)

[0039] 21a Drive sprocket

[0040] 21ap drive sprocket chain track inner diameter circle

[0041] 40 Power transmission chain (endless flexible parts)

[0042] 61 parking gear

[0043] 62 parking axle

[0044] 63 Parking pawl

[0045] 64 parking lever

[0046] 65 control axis

[0047] 66 stop rod

[0048] 70 Support protrusion

[0049] 311 Input shaft (rotating shaft)

[0050] 311 a driven sprocket

[0051] 311ap driven sprocket chain track inner diameter circle

[0052] L1 external tangent

[0053] L2 parallel line

[0054] L3 arc

[0055] O Axis of rotation. DETAILED DESCRIPTION

[0056] 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.

[0057]

Overall structure of the vehicle

[0058] like Figure 1As shown, the 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 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.

[0059] 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 .

[0060] 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.

[0061] [Overall structure of the drive unit]

[0062] like Figure 2 and Figure 3 As 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, a parking mechanism 6, and a drive unit housing 11 that accommodates them.

[0063] 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 .

[0064] The drive unit housing 11 has a motor chamber 12 that accommodates a drive motor 20, a gear chamber 13 that accommodates a reduction gear 30, a chain chamber 14 that accommodates a chain transmission mechanism 4 and a parking mechanism 6, and a controller chamber 15 that accommodates a control device 50. The motor chamber 12 and the gear chamber 13 are arranged in the front-to-back 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 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.

[0065] The driving motor 20 is a so-called inner rotor type motor, which includes a driving shaft 21, a rotor 22 mounted on the driving shaft 21 and rotating integrally with the driving shaft 21, and a stator 23 arranged to be radially opposed to the rotor 22 with a small gap radially outside the rotor 22.

[0066] In this embodiment, the drive motor 20 is arranged in the drive unit 10 with its axial direction (ie, the drive shaft 21) oriented horizontally in the left-right direction. Thus, by arranging the drive shaft 21 oriented horizontally, the vertical dimension of the drive unit 10 can be made compact.

[0067] 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.

[0068] A drive sprocket 21a around which the power transmission chain 40 of the chain transmission mechanism 4 is wound is attached to the left end portion of the drive shaft 21. The drive sprocket 21a rotates integrally with the drive shaft 21.

[0069] The chain transmission mechanism 4 includes a driving sprocket 21a mounted on the driving shaft 21, a driven sprocket 311a mounted on the same plane as the driving sprocket 21a and on an input shaft 311 of a planetary gear mechanism 31 described later, 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.

[0070] 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 .

[0071] 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 .

[0072] 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.

[0073] The input shaft 311 is a hollow shaft, and a left drive shaft 325L described later passes through the inside of the input shaft 311. A driven sprocket 311a around which a power transmission chain 40 of the chain transmission mechanism 4 is wound is mounted at the left end of the input shaft 311. The driven sprocket 311a rotates integrally with the input shaft 311.

[0074] 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.

[0075] 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 .

[0076] 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.

[0077] 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 .

[0078] 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 .

[0079] 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).

[0080] 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.

[0081] The ring gear 317 is an annular internal gear whose inner peripheral surface meshes with each of the second planetary gears 314b. In the present embodiment, the ring gear 317 is fixed to the drive unit case 11, and the ring gear 317 itself does not rotate.

[0082] 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 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.

[0083] 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.

[0084] Next, a power transmission path of the power output from the driving motor 20 will be described.

[0085] The power generated by the driving motor 20 is output from the driving shaft 21, and the driving sprocket 21a installed on the driving shaft 21 rotates integrally with the driving shaft 21. 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 installed 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.

[0086] 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.

[0087] 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.

[0088] 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 .

[0089] 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.

[0090] 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.

[0091] In this way, Figure 3 As 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.

[0092] Next, the chain chamber 14 and the parking mechanism 6 disposed in the chain chamber 14 will be described.

[0093] like Figure 5 As shown, the chain chamber 14 is a space formed by assembling a partition provided on the main housing 111 and a recess provided on the left side cover 112 in a facing manner. In the chain chamber 14, a driving sprocket 21a mounted on the driving shaft 21 is arranged at the front, and a driven sprocket 311a mounted on the input shaft 311 of the planetary gear mechanism 31 is arranged at the rear, and a power transmission chain 40 is wound around the driving sprocket 21a and the driven sprocket 311a.

[0094] The parking mechanism 6 includes a parking gear 61 , a parking shaft 62 , a parking pawl 63 , a parking rod 64 , a control shaft 65 , and a stopper rod 66 .

[0095] The parking gear 61 is disposed on the power transmission path of the drive unit 10, and switches between a locked state in which the parking gear 61 is engaged with the parking pawl 63 to lock the rotation, and an unlocked state in which the parking gear 61 is not engaged with the parking pawl 63 and the rotation is allowed. The parking mechanism 6 is in a parking state in which the power transmission path of the drive unit 10 is braked by putting the parking gear 61 in the locked state, and is in an unlocked state in which the power transmission path of the drive unit 10 is not braked by putting the parking gear 61 in the unlocked state.

[0096] The parking gear 61 is configured to be rotatable integrally with the drive shaft 21 of the drive motor 20. Thus, the layout freedom of the parking gear 61 and the parking mechanism 6 can be improved, and even if there is no space for arranging the parking gear 61 at a position downstream of the drive shaft 21 of the drive motor 20, the parking gear 61 can be arranged in a manner that does not enlarge the drive unit 10.

[0097] In addition, the parking gear 61 is arranged at a position different from the driving sprocket 21a in the direction of the rotation axis of the driving shaft 21 of the driving motor 20. Specifically, the parking gear 61 is arranged on the driving shaft 21 of the driving motor 20 at a position closer to the front end side (left side) of the driving shaft 21 than the driving sprocket 21a. Thus, the parking gear 61 can be prevented from interfering with the driving sprocket 21a and the parking gear 61 can be prevented from interfering with the power transmission chain 40.

[0098] The parking shaft 62 is supported by the drive unit case 11 and has a rotation axis parallel to the rotation axis of the drive shaft 21 of the drive motor 20 .

[0099] The parking pawl 63 is supported to be able to swing around the parking shaft 62 and to swing on the same plane as the parking gear 61. The parking pawl 63 has an engaging claw portion 63a at the front end portion, and switches between an engaged state in which it is engaged with the engaging groove portion 61b of the parking gear 61 and a non-engaged state in which it is not engaged with the engaging groove portion 61b of the parking gear 61. In addition, a pawl spring 67 is arranged between the parking pawl 63 and the drive unit housing 11, and the parking pawl 63 is urged by the pawl spring 67 to be in a non-engaged state.

[0100] The parking rod 64 is supported by the drive unit housing 11 via the parking rod bracket 68 so as to be able to move forward and backward, and moves forward and backward on the same plane as the parking gear 61. The parking rod 64 moves forward and backward between an entry position in which the parking pawl 63 is pressed to put the parking pawl 63 in an engaged state and a retracted position in which the parking pawl 63 is separated from the parking pawl 63 to put the parking pawl 63 in a non-engaged state. In addition, a rod spring 69 is arranged between the parking rod 64 and the parking rod bracket 68, and the parking rod 64 is urged by the rod spring 69 to be located in the retracted position.

[0101] The control shaft 65 has a rotation axis parallel to the rotation axis of the drive shaft 21 of the drive motor 20, and is rotatably supported by the drive unit housing 11 via the support protrusion 70. The control shaft 65 is connected to a parking operation member (not shown) and rotates according to the operation of the parking operation member. In addition, the configuration of the control shaft 65 will be described later.

[0102] The stopper lever 66 is supported so as to be rotatable together with the control shaft 65, and is swung on the same plane as the parking gear 61. The stopper lever 66 swung between a first position for moving the parking lever 64 to the advancing position and a second position for moving the parking lever 64 to the retreating position according to the rotation of the control shaft 65. Thus, the parking mechanism 6 can be switched between the parking state and the non-parking state according to the operation of the parking operating member.

[0103] The stopper lever 66 includes a first extension portion 661 extending from the rotation axis in a direction orthogonal to the rotation axis and connected to the parking lever 64, and a second extension portion 662 extending from the rotation axis in a direction opposite to the first extension portion 661 and engaging with the stopper spring 72. The second extension portion 662 has at least two stopper grooves 662a and 662b arranged along the swinging direction of the stopper lever 66, and the stopper lever 66 is held in the first position by the engagement of the first stopper groove 662a with the stopper spring 72, and the stopper lever 66 is held in the second position by the engagement of the second stopper groove 662b with the stopper spring 72.

[0104] Next, refer to Figures 6 to 10 The arrangement of the control shaft 65 will be further described.

[0105] like Figure 6 As schematically shown, the control shaft 65 is arranged in the power transmission chain 40 when viewed from the rotation axis direction of the drive shaft 21 of the drive motor 20. That is, the control shaft 65 is arranged in the area surrounded by the power transmission chain 40. In this way, the control shaft 65 can be arranged in the power transmission chain 40, which is likely to become a useless space, and the drive unit 10 can be miniaturized.

[0106] However, the power transmission chain 40 is set with a clearance between the sprockets 21a and 311a to allow appropriate swinging in order to perform appropriate power transmission. Therefore, when the control shaft 65 is arranged in the power transmission chain 40, the swinging power transmission chain 40 may contact the support protrusion 70 supporting the control shaft 65. Although it is also considered to arrange the support protrusion 70 in a position that is offset from the power transmission chain 40 in the direction of the rotation axis (left-right direction) so as not to interfere with it, in order to miniaturize the drive unit 10, there is also a possibility that it has to be arranged as Figure 7 As shown, the supporting protrusion 70 on at least one side (the right side in this embodiment) overlaps with the power transmission chain 40 when viewed from above.

[0107] In the drive unit 10 of the present embodiment, when the control shaft 65 is arranged in the power transmission chain 40, in order to prevent the swinging power transmission chain 40 from contacting the support projection 70 that supports the control shaft 65, the arrangement conditions of the control shaft 65 (support projection 70) are set. First, based on Figure 8 An example of the arrangement conditions will be described, based on Fig. 9 And Fig.10 Another example of the arrangement conditions will be described. Figure 8 And Fig. 9 The dashed lines of

[0108] represent the state where the power transmission chain 40 swings upward to the innermost side.

[0109] In an example of the arrangement conditions, as conditions to be satisfied simultaneously, the first condition and the second condition are included.

[0109] The first condition means that, as Figure 8 shown, when the diameter of the support projection 70 of the control shaft 65 is set to D, the axial distance between the drive sprocket 21a (drive shaft 21 of the drive motor 20) and the driven sprocket 311a (input shaft 311 of the planetary gear mechanism 31) is set to X, the diameter of the drive sprocket 21a is set to d1, and the diameter of the driven sprocket 311a is set to d2,

[0110] the relationship D < X - (d1 + d2) / 2 is satisfied.

[0111] By satisfying the first condition, the support projection 70 can be arranged between the drive sprocket 21a and the driven sprocket 311a in a manner that does not interfere with the drive sprocket 21a and the driven sprocket 311a. In addition, the axial distance refers to the distance between the centers of the axes, and the diameters of the sprockets 21a and 311a refer to the distances from the center of the axis to the outermost peripheral surface.

[0112] In addition, the second condition means that, as Figure 8 shown, when the swing amplitude of the power transmission chain 40 is set to A, the rotation axis O of the control shaft 65 is arranged in a region farther than D / 2 + A from the outer tangent line L1 of the innermost diameter circle 21ap (circle with a diameter of dp1) of the chain track connecting the drive sprocket 21a and the innermost diameter circle 311ap (circle with a diameter of dp2) of the chain track of the driven sprocket 311a. In addition, the innermost diameter circles 21ap and 311ap of the chain track are lines (circles) connecting the innermost diameter portions of the power transmission chain 40 engaged with the respective sprockets 21a and 311a.

[0113] By satisfying the second condition, even if the power transmission chain 40 swings and passes through the inner side to the maximum extent, it is possible to avoid the power transmission chain 40 from contacting the support projection 70.

[0114] On the other hand, in another example of the configuration conditions, the conditions to be satisfied simultaneously include the first condition described above and a third condition different from the second condition described above.

[0115] The third condition is that Fig. 9 As shown, when the swing amplitude of the power transmission chain 40 is set to A, the rotation axis O of the control shaft 65 is arranged in a region farther than D / 2 from the arc L3 connecting the parallel line L2, the innermost diameter circle 21ap of the chain track of the driving sprocket 21a, and the innermost diameter circle 311ap2 of the chain track of the driven sprocket 311a, and the parallel line L2 is separated by A toward the support protrusion 70 with respect to the circumferential line L1 shared by the innermost diameter circle 21ap of the chain track of the driving sprocket 21a and the innermost diameter circle 311ap of the chain track of the driven sprocket 311a. The arc L3 is substantially equal to the trajectory of the power transmission chain 40 swinging to the innermost side.

[0116] In addition, the radius r of the arc L3 can be calculated using the following formula. Fig.10 As shown, when the distance between the tangent points of the common external tangent line L1 of the chain track innermost circle 21ap of the driving sprocket 21a and the chain track innermost circle 311ap of the driven sprocket 311a is denoted as B, the following formula (1) holds.

[0117] r 2 =(rA) 2 +(B / 2) 2 (1)

[0118] When this formula is expanded, the following formula (2) is obtained, which is used to calculate the radius r of the arc L3 from the swing amplitude A and the distance B between the tangent points of the external tangent line L1. The swing amplitude A and the distance B between the tangent points of the external tangent line L1 are values ​​determined by the diameters of the drive sprocket 21a and the driven sprocket 311a, the distance between the axes of the drive sprocket 21a and the driven sprocket 311a, and the length and properties of the power transmission chain 40.

[0119] r=(A / 2)+(B 2 / 8A) (2)

[0120] By satisfying the third condition, even if the power transmission chain 40 swings and passes the inner side as far as possible, it is possible to avoid the power transmission chain 40 from contacting the support protrusions 70 .

[0121] 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.

[0122] 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.

[0123] 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 thereto.

[0124] (1) A power transmission device (drive unit 10) comprising:

[0125] Driving source (driving motor 20);

[0126] A speed change unit (chain transmission mechanism 4) that changes the speed of the power of the driving source and transmits it to the driven part; and

[0127] a housing (drive unit housing 11) that accommodates the drive source and the speed change unit,

[0128] in,

[0129] The power transmission device further comprises:

[0130] A drive sprocket (drive sprocket 21a) disposed on the output shaft (drive shaft 21) of the drive source;

[0131] A driven sprocket (driven sprocket 311a), which is arranged on the same plane as the driving sprocket;

[0132] an endlessly flexible member (power transmission chain 40) wound around the driving sprocket and the driven sprocket; and

[0133] A parking gear (parking gear 61 ) is disposed on the output shaft of the driving source.

[0134] According to (1), the degree of freedom in layout of the parking gear is improved.

[0135] (2) The power transmission device according to (1), wherein:

[0136] The parking gear is arranged at a position different from that of the driving sprocket in the rotation axis direction of the output shaft of the driving source.

[0137] According to (2), interference with the drive sprocket can be prevented.

[0138] (3) The power transmission device according to (1), wherein:

[0139] The power transmission device further comprises:

[0140] a parking shaft (parking shaft 62) having a rotation axis parallel to the rotation axis of the output shaft of the drive source; and

[0141] a parking pawl (parking pawl 63) supported by the parking shaft and capable of swinging on the same plane as the parking gear,

[0142] The parking pawl switches between an engaged state in which the parking pawl is engaged with the parking gear and a non-engaged state in which the parking pawl is not engaged with the parking gear, and is urged to enter the non-engaged state.

[0143] According to (3), the driven part can be maintained in the parking state by engaging the parking pawl with the parking gear.

[0144] (4) The power transmission device according to (3), wherein:

[0145] The power transmission device further includes a parking rod (parking rod 64) that can move forward and backward on the same plane as the parking gear.

[0146] The parking rod moves between an entry position capable of pressing the parking pawl and a retreat position separated from the parking pawl, and is urged to be located at the retreat position.

[0147] According to (4), the position of the parking pawl can be controlled by the parking rod.

[0148] (5) The power transmission device according to (4), wherein:

[0149] The power transmission device further comprises:

[0150] a control shaft (control shaft 65) having a rotation axis parallel to the rotation axis of the output shaft of the drive source; and

[0151] a stopper lever (stopper lever 66) supported by the control shaft and capable of swinging on the same plane as the parking gear,

[0152] The detent lever swings between a first position for moving the parking lever to the entry position and a second position for moving the parking lever to the retreat position, and is urged to be located at the second position.

[0153] According to (5), the position of the parking rod can be controlled by the detent rod.

[0154] (6) The power transmission device according to (5), wherein,

[0155] When viewed from the direction of the rotation axis of the output shaft of the drive source, the control shaft is disposed in the endless flexible member.

[0156] According to (6), by disposing the control shaft in the endless flexible member that is likely to become an unused space, the drive device can be miniaturized.

[0157] (7) The power transmission device according to (6), wherein,

[0158] The power transmission device further includes a support projection (support projection 70) that is provided on the housing and supports the control shaft.

[0159] When the diameter of the support projection of the control shaft is D, the axial distance between the output shaft of the drive source and the rotation shaft (input shaft 311) of the driven sprocket is X, the diameter of the drive sprocket is d1, and the diameter of the driven sprocket is d2, the relationship D < X - (d1 + d2) / 2 is satisfied, and,

[0160] When the swing amplitude of the endless flexible member is A, the rotation axis (rotation axis O) of the control shaft is disposed in a region farther than D / 2 + A from the common outer tangent line (outer tangent line L1) of the innermost diameter circle (innermost diameter circle 21ap of the chain track) of the drive sprocket and the innermost diameter circle (innermost diameter circle 311ap of the chain track) of the driven sprocket.

[0161] According to (7), even if the control shaft is disposed in the endless flexible member, it is possible to prevent the endless flexible member from touching the support projection that supports the control shaft.

[0162] (8) The power transmission device according to (6), wherein,

[0163] The power transmission device further includes a support projection (support projection 70) that is provided on the housing and supports the control shaft.

[0164] When the diameter of the support projection of the control shaft is D, the axial distance between the output shaft of the drive source and the rotation shaft (input shaft 311) of the driven sprocket is X, the diameter of the drive sprocket is d1, and the diameter of the driven sprocket is d2, the relationship D < X - (d1 + d2) / 2 is satisfied, and,

[0165] When the swing amplitude of the endless flexible component is set to A, the rotation axis of the control shaft (rotation axis O) is arranged in an area farther than D / 2 from the arc (arc L3) connected by three lines: a parallel line (parallel line L2), the innermost diameter circle of the chain track of the driving sprocket, and the innermost diameter circle of the chain track of the driven sprocket. The parallel line leaves A toward the support protrusion side relative to the common tangent line of the chain track innermost diameter circle of the driving sprocket (chain track innermost diameter circle 21ap) and the chain track innermost diameter circle of the driven sprocket (chain track innermost diameter circle 311ap).

[0166] According to (8), even if the control shaft is arranged in the endless flexible member, it is possible to avoid the endless flexible member from contacting the supporting protrusion that supports the control shaft.

Claims

1. A power transmission device, comprising: A drive source; A speed change unit that changes the speed of the power of the drive source and transmits it to the driven unit; and A housing that houses the drive source and the speed change unit, wherein The power transmission device further comprises: A drive sprocket disposed on the output shaft of the drive source; A driven sprocket disposed on the same plane as the drive sprocket; An endless flexible member wound around the drive sprocket and the driven sprocket; and A parking gear disposed on the output shaft of the drive source.

2. The power transmission device according to claim 1, wherein The parking gear is disposed at a position different from that of the drive sprocket in the rotational axis direction of the output shaft of the drive source.

3. The power transmission device according to claim 1, wherein The power transmission device further comprises: A parking shaft having a rotational axis parallel to the rotational axis of the output shaft of the drive source; and A parking pawl supported by the parking shaft and capable of swinging on the same plane as the parking gear, The parking pawl is switched between an engaged state of engaging with the parking gear and a non-engaged state of not engaging with the parking gear, and is biased to be in the non-engaged state.

4. The power transmission device according to claim 3, wherein The power transmission device further comprises a parking lever that can move forward and backward on the same plane as the parking gear, The parking lever moves between an entering position where it can press the parking pawl and a retracted position where it is separated from the parking pawl, and is biased to be in the retracted position.

5. The power transmission device according to claim 4, wherein The power transmission device further comprises: A control shaft having a rotational axis parallel to the rotational axis of the output shaft of the drive source; and A stop lever supported by the control shaft and capable of swinging on the same plane as the parking gear, The stop lever swings between a first position that moves the parking lever to the entering position and a second position that moves the parking lever to the retracted position, and is biased to be in the second position.

6. The power transmission device according to claim 5, wherein When viewed from the rotational axis direction of the output shaft of the drive source, the control shaft is disposed in the endless flexible member.

7. The power transmission device according to claim 6, wherein The power transmission device further comprises a support projection provided on the housing and supporting the control shaft, When the diameter of the support projection of the control shaft is set as D, the axial distance between the output shaft of the drive source and the rotational shaft of the driven sprocket is set as X, the diameter of the drive sprocket is set as d1, and the diameter of the driven sprocket is set as d2, the relationship D < X - (d1 + d2) / 2 is satisfied, and When the swing amplitude of the endless flexible member is set as A, the rotational axis of the control shaft is disposed in a region farther than D / 2 + A from the outer tangent line common to the innermost diameter circle of the chain track of the drive sprocket and the innermost diameter circle of the chain track of the driven sprocket.

8. The power transmission device according to claim 6, wherein, the power transmission device further includes a support projection that is provided on the housing and supports the control shaft, when the diameter of the support projection of the control shaft is set as D, the axial distance between the output shaft of the drive source and the rotation shaft of the driven sprocket is set as X, the diameter of the drive sprocket is set as d1, and the diameter of the driven sprocket is set as d2, the relationship D < X - (d1 + d2) / 2 is satisfied, and, when the swing amplitude of the endless flexible member is set as A, the rotation axis line of the control shaft is arranged in a region farther than D / 2 from an arc that is in contact with three lines, i.e., a parallel line, the innermost diameter circle of the chain track of the drive sprocket, and the innermost diameter circle of the chain track of the driven sprocket, and this parallel line is separated by A from the common outer tangent line of the innermost diameter circle of the chain track of the drive sprocket and the innermost diameter circle of the chain track of the driven sprocket toward the support projection side.

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