JP2014019263A - Driving device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driving device for a vehicle which can transmit driving force highly efficiently without using a hypoid gear or the like to drive shafts, can adopt even an electric motor having motor characteristics of high torque and high rotation with excellent space efficiency, and can transmit driving force generated at the electric motor to one drive shaft and the other drive shaft, taking account of driving force distribution and differential between these drive shafts.SOLUTION: A rear-wheel driving part 20 includes: an electric motor 3 composed of a stator 3s fixed to a main case 21 and a rotor 3r rotatably supported in the main case 21; a pair of rotating shafts 22L, 22R protruding from both sides of the rotor 3r in a rotation axis direction, for rotating integrally with the rotor 3r; a pair of drive shafts 24L, 24R which are provided at outer ends of the rotating shafts 22L, 22R respectively on the same axes as the rotating shafts, and can transmit driving force by the electric motor 3; and planetary gear mechanisms 23L, 23R for connecting the rotating shafts 22L, 22R with the drive shafts 24L, 24R respectively.

Description

  The present invention relates to a vehicle drive device that outputs a driving force generated by an electric motor from a pair of drive shafts.

  In recent years, various automobiles (electric automobiles, hybrid cars) that use an electric motor as a drive source have been developed and put into practical use. For example, in Japanese Unexamined Patent Publication No. 2003-63265 (hereinafter referred to as Patent Document 1), in a hybrid vehicle in which front wheels are driven by an engine and rear wheels are driven by an electric motor, a first clutch is provided between the electric motor and the left rear wheel. A hybrid vehicle that includes a second clutch between the electric motor and the right rear wheel to control the driving force distribution between the front and rear shafts and to control the driving force distribution between the left and right wheels of the rear wheel The technology of the driving force distribution device is disclosed.

JP 2003-63265 A

  By the way, as in the hybrid vehicle disclosed in Patent Document 1 described above, when the driving force from the electric motor is transmitted to the left and right rear wheel axles, the rotor shaft of the electric motor and the rotation shafts of the left and right rear wheel axles. Therefore, for example, it is necessary to configure the driving force of the electric motor to be transmitted to the axle via a hypoid gear or the like, which may deteriorate the transmission efficiency of the driving force generated by the electric motor. is there. Since the hypoid gear that transmits such a driving force has a relatively large diameter, the space efficiency also deteriorates. Also, even if an attempt is made to employ a large electric motor with high torque and high rotation at a position away from the axle, the size of the electric motor may be limited by the space of the vehicle, and desired performance may not be obtained. .

  The present invention has been made in view of the above circumstances, and can transmit a driving force with high efficiency without using a hypoid gear or the like on the driving shaft, and even if it is an electric motor having high torque and high rotation motor characteristics, it is a space. It can be used efficiently, and the driving force generated by the electric motor can be transmitted to one driving shaft and the other driving shaft in consideration of the driving force distribution between these driving shafts and the differential. It aims at providing the drive device for vehicles.

  A vehicle drive device according to an embodiment of the present invention includes a stator fixed to a main case, an electric motor including a rotor rotatably supported in the main case, and a rotating shaft direction of the rotor from both sides of the rotor of the electric motor. A pair of rotating shafts that rotate integrally with the rotor, and a pair of shafts that are rotatably supported by the main case on the same axis as the rotating shafts at the outer ends of the rotating shafts and capable of transmitting the driving force of the electric motor. Drive shafts, and a planetary gear mechanism for connecting the respective rotary shafts and the drive shafts.

  According to the vehicle drive device of the present invention, the driving force can be transmitted with high efficiency without using a hypoid gear or the like on the drive shaft, and even an electric motor with high torque and high rotation motor characteristics can be efficiently space-efficient. The drive force generated by the electric motor can be transmitted to one drive shaft and the other drive shaft in consideration of the drive force distribution between these drive shafts and the differential. .

It is a schematic block diagram of the drive system of the vehicle based on one Embodiment of this invention. It is a skeleton figure of the rear-wheel drive part concerning one embodiment of the present invention. It is a section explanatory view of the rear-wheel drive part concerning one embodiment of the present invention. It is the L section enlarged view of FIG. 3 based on one Embodiment of this invention. It is the R section enlarged view of Drawing 3 concerning one embodiment of the present invention. It is a 1st operation explanatory view of the rear-wheel drive part concerning one embodiment of the present invention. It is a 2nd operation explanatory view of the rear-wheel drive part concerning one embodiment of the present invention. It is a 3rd operation explanatory view of the rear-wheel drive part concerning one embodiment of the present invention. It is a 4th operation explanatory view of the rear-wheel drive part concerning one embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In FIG. 1, reference numeral 1 denotes a vehicle. In the present embodiment, the vehicle 1 is a hybrid vehicle in which the front wheels are driven by the driving force generated by the engine 2 and the rear wheels are driven by the driving force generated by the electric motor 3. It is configured.

  In the front wheel drive unit 4 of the vehicle 1, the driving force generated by the engine 2 is input from the torque converter 5 to the automatic transmission 6, and the shift output is transmitted to the front differential device 8 via the front drive shaft 7 of the front wheel, It is transmitted to the left and right front wheels 9L, 9R. These torque converter 5, automatic transmission 6, front differential device 8, other gears, shafts and the like are all housed in a single housing 10 at the front of the vehicle body.

  In the rear wheel drive unit 20 of the vehicle 1, the electric motor 3 connected to a battery / battery device (not shown) is fixed at a substantially center in the main case 21.

  As shown in FIGS. 2 to 5, the electric motor 3 has a stator 3 s fixed at substantially the center in the main case 21, the rotor 3 r is rotatably supported, and the rotor 3 r from both sides of the rotor 3 r in the direction of the rotation axis. The left and right rotating shafts 22L and 22R that rotate integrally with each other are projected. The driving force generated by the electric motor 3 is transmitted from the left and right drive shafts 24L, 24R to the left and right rear wheels 25L via the left and right rotating shafts 22L, 22R and the pair of left and right planetary gear mechanisms (planetary gear mechanisms) 23L, 23R. , 25R.

  The main case 21 fixes a stator 3s of the electric motor 3 and supports a rotor 3r rotatably supported via a bearing, and a rotor 3r extending from the center housing 31 in the vehicle width direction. The cylindrical side housing portions 32L and 32R extending left and right along the rotation center axis are integrally formed. The center housing portion 31 and the side housing portion 32L, and the center housing portion 31 and the side housing portion 32R are connected to each other. Partition walls 33L and 33R for partitioning are formed.

  Further, cylindrical portions 34L and 34R extending along the rotation center axis are integrally extended on the partition walls 33L and 33R. An opening 35 that opens to the rear end of the center housing portion 31 is closed by a rear cover 36.

  The left and right side housings 37L and 37R are joined to the outer ends of the side housing portions 32L and 32R of the main case 21, and the shaft through holes 38a are opened at the outer ends of the side housings 37L and 37R, respectively. Side covers 39L and 39R are joined.

  The inner ends of the left and right drive shafts 24L and 24R are rotatably fitted to the outer ends of the left and right rotation shafts 22L and 22R provided integrally on both sides of the rotor 3r of the electric motor 3, respectively. The rotor 3r, the left and right rotating shafts 22L and 22R, and the left and right drive shafts 24L and 24R are arranged on a coaxial core. The drive shafts 24L and 24R pass through the shaft through holes 38a of the side covers 39L and 39R, and are rotatably supported by the side covers 39L and 39R via bearings.

  As shown in FIG. 4, the left rotation shaft 22L from the rotor 3r of the electric motor 3 and the left drive shaft 24L are connected by a planetary gear mechanism 23L so that power can be transmitted, and the rotation shaft 22L and the planetary gear mechanism 23L are connected to each other. A left clutch mechanism 42L as a second clutch means is disposed between the carrier 41 and a left brake mechanism 43L as a first clutch means is provided between the side housing portion 32L of the main case 21 and the carrier 41. Has been placed.

  The planetary gear mechanism 23L is composed of a compound planetary gear without a ring gear, and is formed on the outer periphery of the first sun gear 44 formed on the outer peripheral surface of the left rotation shaft 22L and the inner end of the drive shaft 24L. A second sun gear 45 having a smaller diameter than the first sun gear 44, a first pinion 46 having a smaller diameter than the first sun gear 44 and meshing with the first sun gear 44, and the first pinion 46, and A second pinion 47 having a diameter larger than that of the first pinion 46 and meshing with the second sun gear 45, and the integrally formed first pinion 46 and second pinion 47 are rotatable via a needle bearing 48a. The carrier 41 has a pinion shaft 48 to be supported, and the carrier 41 bears against the left rotation shaft 22L and the left drive shaft 24L. It is rotatably supported through a ring.

  The planetary gear mechanism 23L includes the first and second sun gears 44 and 45 and the number of teeth of the first and second pinions 46 and 47 arranged around the first and second sun gears 44 and 45. It has a differential function by appropriately setting.

  The combined force of the separation load and the tangential load acting on the meshing point of the first sun gear 44 and the first pinion 46 and the gear train and the meshing point of the gear train of the second sun gear 45 and the second pinion 47 is the first. Friction torque is applied to the rotation of the first and second pinions 46 and 47 supported on the pinion shaft 48 by acting on the needle bearing 48a between the first and second pinions 46 and 47 and the pinion shaft 48. Due to this friction torque, the differential between the left rotating shaft 22L and the left drive shaft 24L is limited. That is, the planetary gear mechanism 23L enables differential between the left rotating shaft 22L and the left drive shaft 24L, and limits the differential to transmit torque from the left rotating shaft 22L to the left drive shaft 24L. Dynamic restriction function is provided.

  In the present embodiment, the left clutch mechanism 42L is configured by hydraulic multi-plate friction engagement means, penetrates through the left cylindrical portion 34L, and passes through a needle bearing on the outer peripheral surface of the left rotating shaft 22L. A clutch drum 52 is provided on a cylindrical base 51 that is rotatably supported. An end of the clutch drum 52 is spline-fitted to the carrier 41 of the planetary gear mechanism 23L so as to be able to transmit power. On the other hand, the clutch hub 53 is arranged by spline fitting at its base end so that power can be transmitted to the rotating shaft 22L.

  A slidable annular piston 54 is fitted between the outer peripheral surface of the base 51 and the inner peripheral surface of the clutch drum 52, and a hydraulic chamber 55 </ b> L is formed between the clutch drum 52 and the piston 54. . On the opposite side of the hydraulic chamber 55L and the piston 54, a retainer 56 is locked to the base 51 by a clip, and a pressing force is urged to the piston 54 by a return spring 57 disposed between the piston 54 and the retainer 56. Yes.

  A plurality of clutch discs 59a whose outer periphery is fitted in spline grooves 58a formed on the inner peripheral surface of the clutch drum 52, and a plurality of clutches whose inner periphery is fitted in spline grooves 53a formed on the outer peripheral surface of the clutch hub 53. Clutch disks 59b are alternately disposed, and a retaining plate 59d is disposed in contact with a snap ring 59c fixed to the clutch drum 52.

  The clutches 59a and 59b are pressed by the control oil pressure supplied to the hydraulic chamber 55L against the retaining plate 59d that contacts the snap ring 59c fixed to the clutch drum 52 via the piston 54, and the clutches frictionally engage with each other. Torque is transmitted between the clutch drum 52 and the clutch hub 53 by the disks 59a and 59b. As a result, the clutch hub 53 transmits power between the left rotating shaft 22 </ b> L with which the spline is engaged and the carrier 41 of the planetary gear mechanism 23 </ b> L coupled to the clutch drum 52. Further, the friction engagement force, that is, the transmission torque of each of the clutch disks 59a and 59b is controlled in accordance with the control hydraulic pressure supplied to the hydraulic chamber 55L. Specifically, a fully engaged state in which the clutch disks 59a and 59b are completely engaged, a released state in which the engagement of the clutch disks 59a and 59b is completely released, and a state in which the clutch disks 59a and 59b are in a slip state The slip engagement state is controlled by friction engagement.

  In the present embodiment, the brake mechanism 43L is constituted by hydraulic multi-plate friction engagement means, and is formed on the inner peripheral surface of the side housing portion 32L of the main case 21 so as to extend in parallel with the rotation center axis. A brake drum 62 is formed in the side housing portion 32L by the plurality of spline grooves 61a, and a plurality of splines 63a are formed on the outer peripheral surface of the clutch drum 52 to form a brake hub 63 that is integral with the clutch drum 52.

  A slidable annular piston 64 is fitted between the inner peripheral surface of the side housing portion 32L and the outer peripheral surface of the cylindrical portion 34L, and a hydraulic chamber 65L is formed between the partition wall 33L and the piston 64. Yes.

  A retainer 66 is locked to the cylindrical portion 34L by a clip on the opposite side between the hydraulic chamber 65L and the piston 64, and a pressing force is applied to the piston 64 by a return spring 67 disposed between the piston 64 and the retainer 66. ing.

  A plurality of brake disks 68a whose outer circumferences are fitted into spline grooves 61a formed on the inner circumference of the brake drum 62, and a plurality of brake disks whose inner circumferences are fitted into spline grooves 63a formed on the outer circumferential surface of the brake hub 63. 68b are alternately arranged, and a retaining plate 68d is arranged in contact with the snap ring 68c fixed to the brake drum 62.

  Each brake disc 68a and 68b is pressed against a retaining plate 68d abutting against a snap ring 68c fixed to the brake drum 62 via a piston 64 by a control hydraulic pressure supplied to the hydraulic chamber 65L, and frictionally engaged with each other. The disks 68a and 68b are configured to suppress the rotation of the brake hub 63 relative to the brake drum 62. Thereby, the rotation of the carrier 41 coupled to the clutch drum 52 in which the brake hub 63 is integrally formed with respect to the side housing portion 32L in which the brake drum 62 is formed is controlled. That is, the friction engagement force of each brake disk 68a and 68b is controlled in accordance with the control hydraulic pressure supplied to the hydraulic chamber 65L, and the brake disk 68a and 68b are completely engaged. It is controlled to a release state in which the engagement with 68b is completely released, and a slip engagement state in which each brake disk 68a and 68b frictionally engages in the slip state.

  By providing the clutch mechanism 42L and the brake mechanism 43L configured as described above, the brake mechanism 43L is released, and the clutch mechanism 42L is brought into a completely engaged state, whereby the left rotation shaft 22L and the carrier 41 of the planetary gear mechanism 23L. Are coupled and rotated at the same speed in the same direction, the first pinion 46 and the second pinion 47 are not planetarily rotated, and the first sun gear 44, the first pinion 46, the second pinion 47, and the second pinion 47 are engaged with each other. The relative rotation with the second sun gear 45 is prevented, and the left rotation shaft 22L and the drive shaft 24L rotate integrally.

  Further, the first pinion 46 and the second pinion 46 integrally formed by completely engaging the brake mechanism 43L to fix the carrier 41 of the planetary gear mechanism 23L to the side housing portion 32L of the main case 21 and releasing the clutch mechanism 42L. The planetary rotation of the pinion 47 becomes possible.

As a result, the drive shaft 24L has the number of teeth of the gear train by the first pinion 46 meshed with the first sun gear 44 formed on the rotation shaft 22L and the first pinion with respect to the rotation speed of the left rotation shaft 22L. The planetary gear mechanism 23L functions as a speed increasing mechanism by increasing the speed according to the number of teeth of the gear train of the second sun gear 45 that meshes with the second pinion 47 integrally formed with 46. That is, the transmission torque by the planetary gear mechanism 23L is transmitted from the rotating shaft 22L to the drive shaft 24L. That is, according to the planetary gear mechanism 23L according to the present embodiment, it is possible to increase the speed without increasing the rotation of the rotating shaft 22L.

  On the other hand, as shown in FIG. 5, the right rotation shaft 22R from the rotor 3r of the electric motor 3 and the right drive shaft 24R are connected by a planetary gear mechanism 23R so that power can be transmitted, and the rotation shaft 22R and the planetary gear mechanism are connected. The right clutch mechanism 42R as the second clutch means is disposed between the carrier 41 of the 23R and the right brake mechanism as the first clutch means between the side housing portion 32R of the main case 21 and the carrier 41. 43R is arranged.

  The planetary gear mechanism 23R, the clutch mechanism 42R, and the brake mechanism 43R have the same configuration as the left planetary gear mechanism 23L, clutch mechanism 42L, and brake mechanism 43L described with reference to FIG. Detailed description of this part is omitted.

  The hydraulic chambers 55L and 55R of the clutch mechanisms 42L and 42R and the hydraulic chambers 65L and 65R of the brake mechanisms 43L and 43R are connected to a hydraulic drive unit (not shown), respectively. The hydraulic pressure for each hydraulic chamber is controlled by a control signal from the control unit 80.

  The vehicle 1 is equipped with a front wheel drive control unit 70 that controls the front wheel drive unit 4 and a rear wheel drive control unit 80 that controls the rear wheel drive unit 20. The front wheel drive control unit 70 and the rear wheel drive control unit are mounted on the vehicle 1. 80 is connected to sensors and switches (not shown) necessary for controlling each drive. Further, the front wheel drive control unit 70 and the rear wheel drive control unit 80 are connected to transmit and receive signals of respective control states.

  For example, the front wheel drive control unit 70 performs fuel injection control and ignition timing for the engine 2 based on vehicle information such as intake air amount, throttle opening, engine water temperature, intake air temperature, oxygen concentration, crank angle, accelerator opening, and the like. The control for the known engine such as the control and the control of the electronically controlled throttle valve is performed, and the front wheel 9L, according to the driving force generated in the rear wheel drive control unit 80, the driving force characteristic set in advance, etc. The driving force to be generated by 9R is controlled.

  The rear wheel drive control unit 80 is provided as a control means, based on the control state of the front wheel drive control unit 70, the traveling state of the vehicle 1 such as the vehicle speed, the accelerator opening, the brake operation state, the battery state, etc. The electric motor 3 calculates the driving force generated in the rear wheels 25L and 25R, outputs the amount of electric power necessary to generate the driving force to the battery / battery device, and supplies the electric power from the battery / battery device to the electric motor 3. On the other hand, the clutch mechanisms 42L and 42R and the brake mechanisms 43L and 43R are actuated in a predetermined manner as needed.

  In addition, the rear wheel drive control unit 80 sets a target yaw moment of the vehicle 1 according to the traveling state and turning state of the vehicle 1 such as the vehicle speed, the steering angle, the lateral acceleration, the yaw rate, and the longitudinal acceleration, for example. The clutch mechanisms 42L and 42R and the brake mechanisms 43L and 43R are actuated in a predetermined manner to control the distribution of driving force between the left and right wheels.

  Further, the rear wheel drive control unit 80, when coasting in which the driver travels with the accelerator opened or during deceleration traveling, rotates the rotor 3r of the electric motor 3 by the rotation of the rear wheels 25L and 25R.・ Energize the battery device to regenerate energy.

  Next, the operation of the above configuration will be described. In the front wheel drive unit 4 of the vehicle 1, the driving force generated by the engine 2 is input from the torque converter 5 to the automatic transmission 6, and the shift output is transmitted to the front differential device 8 via the front drive shaft 7 of the front wheel, It is transmitted to the left and right front wheels 9L, 9R.

  During normal straight traveling, the rear wheel drive control unit 80 causes the rear wheel drive unit 20 to execute the normal straight traveling mode, and the brake mechanisms 43L and 43R of the planetary gear mechanisms 23L and 23R are operated as shown in FIG. While being released together, the control hydraulic pressure set in advance is supplied to the hydraulic chambers 55L and 55R of the clutch mechanisms 42L and 42R. The driving force generated in the electric motor 3 according to the engagement state of the clutch mechanisms 42L and 42R accompanying the supply of the control hydraulic pressure is transmitted to the drive shaft 24L from the left rotation shaft 22L (the broken line in FIG. 6). DL) and drive torque (broken line DR in FIG. 6) transmitted from the right rotation shaft 22R to the drive shaft 24R.

  Here, when the left clutch mechanism 42L is in a fully engaged state, the left clutch mechanism 42L is completely engaged, whereby the rotary shaft 22L and the carrier 41 of the planetary gear mechanism 23L are completely coupled so as to be able to transmit power, so that the first clutch mechanism 42L is fully engaged. The pinion 46 and the second pinion 47 of the first and second pinions 47 stop rotating on a planetary axis, and the first sun gear 44 and the first pinion 46, and the second pinion 47 and the second sun gear 45, which are meshed with each other, are prevented from rotating relative to each other. 22L and the drive shaft 24L rotate integrally to transmit a driving force to the left rear wheel 25L.

  Similarly, the right rotating shaft 22R and the carrier 41 of the planetary gear mechanism 23R are coupled to each other so that the first pinion 46 and the second pinion 47 do not planetarily rotate, and the first sun gear 44 and the first pinion 46, which mesh with each other, The relative rotation between the second pinion 47 and the second sun gear 45 is prevented, and the rotation shaft 22R and the drive shaft 24R rotate integrally to transmit the driving force to the right rear wheel 25R. As described above, in a normal straight traveling state, the driving force generated by the electric motor 3 is equally distributed to the left and right drive shafts 24L and 24R, and good straight traveling performance can be ensured.

  The rear-wheel drive control unit 80 causes the rear-wheel drive unit 20 to execute a speed-up / straight-running travel mode during straight travel at the time of speed increase, and as shown in FIG. 7, each clutch mechanism 42L of the planetary gear mechanisms 23L and 23R. , 42R are both released, and a preset control hydraulic pressure is supplied to the hydraulic chambers 65L, 65R of the brake mechanisms 43L, 43R. Each carrier 41 of the planetary gear mechanisms 23L, 23R is fixed to the main case 21 in accordance with the engagement state of the brake mechanisms 43L, 43R accompanying the supply of the control hydraulic pressure.

  Then, power is transmitted from the first sun gear 44 formed on the left rotation shaft 22L to the first pinion 46 that is supported by the pinion shaft 48 and meshes with the first sun gear 44, and is integrally formed with the first pinion 46. Power is transmitted to the second sun gear 45 that meshes with the second pinion 47 that has been made. As a result, the drive shaft 24L follows the number of teeth of the first sun gear 44 and the first pinion 46 and the number of teeth of the second pinion 47 and the second sun gear 45 with respect to the rotational speed of the left rotation shaft 22L. While rotating at an increased speed, a transmission torque by the planetary gear mechanism 23L is transmitted (broken line DL in FIG. 7).

  Similarly, power is transmitted from the first sun gear 44 formed on the right rotation shaft 22 </ b> R to the first pinion 46 that is supported by the pinion shaft 48 and meshes with the first sun gear 44, and is integrated with the first pinion 46. Power is transmitted to the second sun gear 45 that meshes with the formed second pinion 47. As a result, the drive shaft 24R follows the number of teeth of the first sun gear 44 and the first pinion 46 and the number of teeth of the second pinion 47 and the second sun gear 45 with respect to the rotational speed of the right rotation shaft 22R. While rotating at an increased speed, the transmission torque by the planetary gear mechanism 23R is transmitted (broken line DR in FIG. 7). Thus, according to the present embodiment, the brake mechanisms 43L and 43R are controlled to engage with each other without increasing the rotation speed of the electric motor 3, and the clutch mechanisms 42L and 42R are released. By controlling, it is possible to secure high-speed straight running performance by distributing torque to the left and right. For this reason, even an electric motor with a small output can be adopted, and the number of revolutions of the electric motor 3 can be suppressed to easily set power saving travel.

  In addition, when switching the speed by such clutch mechanisms 42L and 42R and brake mechanisms 43L and 43R, in order to avoid a sudden change in speed, it is synchronized with the driving force control (speed control) by the front wheel drive control unit 70. In order to avoid a sudden change in speed, it is desirable to control the engagement and release of the clutch mechanisms 42L and 42R and the brake mechanisms 43L and 43R using slip engagement.

  Further, the rear wheel drive control unit 80 causes the rear wheel drive unit 20 to execute the left and right wheel drive force control mode during winding travel. For example, when turning left, the rear wheel drive unit 20 controls left turn drive force control. Controlled by mode. FIG. 8 is an operation explanatory diagram showing a driving force transmission path in the left turning driving force control mode by an arrow DR.

  In the left turning driving force control mode, the left brake mechanism 43L that is inside the turn is released and the left clutch mechanism 42L is released, while the right brake mechanism 43R that is outside the turn is fully engaged. The carrier 41 of the right planetary gear mechanism 23R is fixed to the main case 21, and the clutch mechanism 42R is released.

  Thus, the driving force generated by the electric motor 3 is transmitted from the first sun gear 47 formed on the right rotation shaft 22R to the first pinion 46 that meshes with the first sun gear 47, and the first Power is transmitted to a second sun gear 45 that meshes with a second pinion 47 formed integrally with the first pinion 46. In this way, the drive shaft 24R follows the number of teeth of the first sun gear 47 and the first pinion 46 and the number of teeth of the second pinion 47 and the second sun gear 46 with respect to the rotational speed of the right rotation shaft 22R. While rotating at a higher speed, the transmission torque by the planetary gear mechanism 23R is transmitted.

  On the other hand, the drive torque obtained by reducing the drive torque transmitted to the right drive shaft 24R is distributed to the left rotation shaft 22L and transmitted to the left drive shaft 24L via the planetary gear mechanism 23L. As a result, the right drive shaft 24R on the outer side of the turning is driven to rotate at an increased speed with respect to the left drive shaft 24L on the inner side of the turning, and the right rear wheel 25R having a larger turning radius than that of the left rear wheel 25L Thus, the loss of the driving torque of the left rear wheel 25L is eliminated, and the driving torque is positively distributed to the right rear wheel 25R side so that the left turning traveling can be easily performed and the turning performance is improved.

  In this turning traveling, the left planetary gear mechanism 23L disposed between the left rotation shaft 22L and the drive shaft 24L is provided with a gear train of the first sun gear 44 and the first pinion 46 formed on the rotation shaft 22L. And the differential rotation between the rotation shaft 22L and the drive shaft 24L is allowed by the gear train of the second sun gear 45 formed on the second pinion 47 and the drive shaft 24L, and the left rear wheel 25L and the right rear wheel 25R. The braking phenomenon due to the difference in rotation can be avoided. That is, the left planetary gear mechanism 23L functions as a differential mechanism.

  Further, when the left clutch mechanism 42L is controlled to be in a slip engagement state according to a preset steering angle or the like, the transmission torque to the left drive shaft 24L is controlled via the planetary gear mechanism 23L, and the left drive shaft 24L is controlled. A part of the drive torque on the side flows to the right drive shaft 24R side, and the torque distribution ratio to the left and right drive shafts 24L, 24R is controlled to further improve the turning performance. Further, by controlling the clutch mechanisms 42L and 42R to the slip engagement state, the occurrence of a tight corner braking phenomenon due to the difference in rotational radius between the front wheels 9L and 9R and the rear wheels 25L and 25R is avoided, and the turning traveling performance is improved. It can be secured.

  Further, the left brake mechanism 43L is precisely controlled from the released state to the slip state in accordance with the left turn traveling state to control the rotational speed of the left drive shaft 24L, and the right side drive in accordance with the slip state of the brake mechanism 43L. The turning performance can be further improved by flowing a part of the driving torque of the shaft 24L toward the left driving shaft 24L to precisely control the torque distribution ratio.

  Further, the rear wheel drive control unit 80 controls the rear wheel drive unit 20 to the differential mode during low-speed turning traveling. For example, at the time of low speed left turn, the rear wheel drive unit 20 is controlled to the left turn differential control mode. FIG. 9 is an operation explanatory view showing the driving force transmission path in the left turn differential control mode by an arrow DR.

  In the left turn differential control mode, both the left and right brake mechanisms 43L and 43R are released, the right clutch mechanism 42R is completely engaged according to the turning angle and the like, and the left clutch mechanism 42L is released. By the complete engagement of the right clutch mechanism 42R, the right rotation shaft 22R and the carrier 41 of the planetary gear mechanism 23R are coupled, so that the first pinion 46 and the second pinion 47 are not planetarily rotated and mesh with each other. Relative rotation between the sun gear 44 and the first pinion 46 and the second pinion 47 and the second sun gear 45 is prevented, and the rotation shaft 22R and the drive shaft 24R rotate integrally, and drive torque is applied to the right rear wheel 25R. Communicated.

  On the other hand, the drive torque obtained by reducing the drive torque transmitted to the right drive shaft 24R is distributed to the left rotation shaft 22L and transmitted to the left drive shaft 24L via the planetary gear mechanism 23L.

  At this time, the left planetary gear mechanism 23L disposed between the left rotation shaft 22L and the drive shaft 24L has a gear train of the first sun gear 44 and the first pinion 46 formed on the rotation shaft 22L and the second pinion 46. The differential rotation between the rotation shaft 22L and the drive shaft 24L is allowed by the gear train of the second sun gear 45 formed on the pinion 47 and the drive shaft 24L, and the inner wheel 25L and the outer wheel 25R are turned. The braking phenomenon due to the rotation difference can be avoided. That is, the planetary gear mechanism 23L performs a differential function.

  Further, the rear wheel drive control unit 80 controls the left clutch mechanism 42L to a slip state during low-μ road traveling, thereby limiting the differential between the rotation shaft 22L and the carrier 41 between the planetary gear mechanism 23L and the planetary gear mechanism 23L. The transmission torque to the drive shaft 24L is increased by limiting the differential between the rotary shaft 22L and the drive shaft 24L. By increasing the driving torque on the drive shaft 24L side, it is possible to prevent the vehicle from slipping, prevent the driving force from being secured, or to prevent the tail from swinging, and improve the running performance. In addition, the vehicle attitude control with respect to the accelerator operation is improved. That is, the clutch mechanism 42L has an LSD function that suppresses the differential between the left and right drive shafts 24L and 24R to ensure running performance.

  As described above, according to the rear wheel drive unit 20 according to the embodiment of the present invention, the rotor 3r protrudes from both sides of the rotor 3r of the electric motor 3 fixed to the approximate center of the main case 21 in the rotational axis direction of the rotor 3r. The planetary gear mechanisms 23L and 23R are disposed between the pair of rotating shafts 22L and 22R that rotate integrally with the left and right drive shafts 24L and 24R, and are disposed between the respective carriers 41 of the planetary gear mechanisms 23L and 23R and the main case 21. By engaging and controlling the brake mechanisms 43L and 43R, and the clutch mechanisms 42L and 42R disposed between the respective carriers 41 and the rotary shafts 22L and 22R, according to the traveling state, by the rear wheel drive control unit 80. The differential function and differential limiting function of the left and right rear wheels 25L, 25R are obtained. For this reason, the configuration is greatly simplified as compared with the conventional differential device in which the differential mechanism portion and the driving force distribution mechanism portion are individually arranged. Along with the simplification of this configuration, the rear wheel drive unit 20 can be reduced in size and weight, and the in-vehicle performance of the rear wheel drive unit 20 can be improved.

  Furthermore, various drive force distribution ratios to the left and right rear wheels 25L and 25R can be easily obtained by changing the gear specifications of the planetary gear mechanisms 23L and 23R and controlling the engagement of the brake mechanisms 43L and 43R and the clutch mechanisms 42L and 42R. The degree of freedom in design of the driving force distribution control by the rear wheel drive unit 20 is large, and excellent turning traveling performance and running performance by the LSD function can be improved.

  Further, by integrally forming the clutch drums of the clutch mechanisms 42L and 42R and the brake hubs 63 of the brake mechanisms 43L and 43R, the clutch drum and the brake hub can be shared, and the configuration can be simplified. . In particular, by disposing the brake hub 63 on the outer periphery of the clutch drum 52, the brake mechanisms 43L and 43R are disposed on the coaxial core on the outer periphery of the clutch mechanisms 42L and 42R, and the clutch mechanisms 42L and 42R and the brake mechanisms 43L and 43R are installed. Shortening in the left-right direction of the main case 21 to be accommodated is obtained, and miniaturization and weight reduction are ensured.

  And according to the rear-wheel drive part 20 by embodiment of this invention, with the conventional differential apparatus, the differential gear of the space in which the differential gear was provided was abolished, and the electric motor 3 is arrange | positioned in this vacant space. In addition, since the hypoid gear that transmits the driving force to the differential device can be omitted, the driving force generated by the electric motor 3 can be output as it is without causing a decrease in efficiency due to the hypoid gear or the like, and the high-efficiency rear wheel drive unit 20 can be output. It can be.

  In addition, since the electric motor 3 is provided in a space where the conventional differential gear is provided, the electric motor 3 is excellent in space efficiency. Further, since the electric motor 3 having a large motor diameter can be employed, the motor torque can be amplified. is there.

  Furthermore, according to the rear wheel drive unit 20 according to the present embodiment, the drive shafts 24L and 24R are connected to the left and right of the electric motor 3 via the planetary gear mechanisms 23L and 23R, so that the planetary gear mechanisms 23L and 23R are connected. By controlling as described above, the above-described differential function, differential limiting function, and driving force distribution function can be obtained, and excellent running performance can be obtained.

  Further, as described above, according to the rear wheel drive unit 20 according to the present embodiment, the clutch mechanism is controlled by controlling the brake mechanisms 43L and 43R to be engaged without particularly increasing the rotational speed of the electric motor 3. By controlling 42L and 42R in the direction of releasing, it is possible to secure high-speed straight traveling performance with right and left equal torque distribution. For this reason, even an electric motor with a small output can be adopted without depending on the motor diameter, and the number of revolutions of the electric motor 3 can be suppressed to easily set the power saving travel.

  In the embodiment of the present invention, the example in which the front wheels are driven by the driving force generated by the engine 2 and the rear wheels are driven by the driving force generated by the electric motor 3 is used in the rear wheel driving unit 20 of the hybrid vehicle. However, it goes without saying that it can also be adopted for the front wheels, and if the driving device according to the present embodiment is adopted for the front wheels and the rear wheels, an all-wheel drive electric vehicle can be easily realized. Further, the present invention can be applied to a hybrid vehicle in which the front wheels are driven by the driving force generated by the electric motor 3 and a vehicle in which the rear wheels are driven by the driving force generated by the engine.

  Further, in the embodiment of the present invention, the electric motor 3 is provided between the left and right wheels, and the drive device that drives the left wheel and the right wheel has been described as an example. However, the electric motor 3 is provided between the front and rear shafts, The present invention can also be applied to a drive device that drives the rear shaft.

  Furthermore, in the embodiment of the present invention, an example is adopted in which the front wheels are driven by the driving force generated by the engine 2 and the rear wheels are driven by the rear wheel driving unit 20 driven by the driving force generated by the electric motor 3. Although demonstrated, it is applicable also to the vehicle which does not have the drive device by the engine 2. FIG.

1 Vehicle 2 Engine 3 Electric motor (electric motor)
3s Stator 3r Rotor 4 Front wheel drive unit 9L, 9R Front wheel 20 Rear wheel drive unit 21 Main case 22L, 22R Rotating shaft 23L, 23R Planetary gear mechanism (planetary gear mechanism)
24L, 24R Drive shaft 25L, 25R Rear wheel 41 Carrier 42L, 42R Clutch mechanism (second clutch means)
43L, 43R Brake mechanism (first clutch means)
44 first sun gear 45 second sun gear 46 first pinion 47 second pinion 70 front wheel drive control unit 80 rear wheel drive control unit (control means)

Claims (4)

An electric motor comprising a stator fixed to the main case and a rotor rotatably supported in the main case;
A pair of rotating shafts protruding from both sides of the rotor of the electric motor in the rotating shaft direction of the rotor and rotating integrally with the rotor;
A pair of drive shafts rotatably supported by the main case on the same axis as the rotation shafts at the outer ends of the respective rotation shafts, and capable of transmitting the driving force by the electric motor;
A planetary gear mechanism that connects between each of the rotating shafts and the drive shaft;
A vehicle drive device comprising:   In each of the planetary gear mechanisms, a first sun gear is provided at an outer end of the rotating shaft, a second sun gear having a smaller diameter than the first sun gear is provided at an inner end of the drive shaft, A first pinion having a smaller diameter than the first sun gear meshing with the first sun gear, and a second pinion integrally formed with the first pinion and having a larger diameter than the first pinion and meshing with the second sun gear. 2. The vehicle drive device according to claim 1, further comprising a pinion and a carrier that rotatably supports the first pinion and the second pinion.   Each of the planetary gear mechanisms includes first clutch means between the carrier and the main case, and second clutch means between the carrier and the rotating shaft, so that the vehicle travels. 3. The vehicle drive device according to claim 2, further comprising control means for controlling engagement of the first clutch means and the second clutch means according to a state.   The pair of drive shafts is characterized in that one drive shaft transmits driving force to the left wheel of the vehicle and the other drive shaft transmits driving force to the right wheel of the vehicle. The vehicle drive device according to any one of claims 1 to 3.

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