JP2011102112A - Electric vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric vehicle, immediately shutting off the transmission of power from an electric motor to wheels when the electric motor breaks down. <P>SOLUTION: A one-way clutch 20 is assembled in a power transmission system for transmitting the driving force of the electric motor 10 to the front wheels 2. When the electric motor 10 fails, the one-way clutch 20 is raced to immediately shut off the transmission of power from the electric motor 10 to the front wheels 2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electric vehicle that causes a vehicle to travel only by driving an electric motor mounted on the vehicle.

  In an electric vehicle in which the vehicle is driven only by driving the electric motor, when the electric motor or a control means for controlling the electric motor fails during driving of the vehicle, the driving wheel is locked and suddenly braked, and the steering becomes impossible. It becomes extremely dangerous.

  In order to eliminate such inconvenience, an electric vehicle is provided with a fail-safe function. As an electric vehicle having a fail-safe function, one described in Patent Document 1 has been conventionally known.

  In the electric vehicle described in Patent Document 1, a clutch is incorporated in a power transmission system from an electric motor to wheels, and a determination unit that determines a failure of a control unit that controls the operation of the electric motor is provided. When it is determined that the control means is out of order, the clutch is disengaged by the hydraulic actuator, and power transmission from the electric motor to the wheels is interrupted to avoid sudden braking.

Japanese Patent No. 3747836

  By the way, when a clutch such as a dog clutch is disengaged by an actuator using hydraulic pressure as a drive source as in the conventional electric vehicle described above, a mechanical failure such as seizure of an electric motor or seizure of a support bearing suddenly occurs. In this case, a slight time lag occurs from the occurrence of the failure until the clutch is disengaged, and there is a problem in that the wheels are locked during that time, the steering becomes impossible, and the vehicle suddenly stops.

  In addition, since the clutch is controlled by an actuator that uses hydraulic pressure as a drive source, a hydraulic pump, a hydraulic cylinder, and hydraulic piping are required, resulting in a complicated structure and a large energy loss.

  Here, in a general pure electric vehicle, a multi-stage transmission is not required, and a single-stage or two-stage transmission is used. Therefore, the number of parts is smaller than that of an engine vehicle or a hybrid vehicle. The connection backlash from the motor to the wheel is small.

  Further, the electric motor has a larger torque from the start than the engine, and also has a large inertia moment (inertia) of the rotor of the electric motor.

  For this reason, if you depress the accelerator pedal strongly when the electric vehicle starts at a low speed and then release the depression, the large torsion that occurs in the drive parts when the pedal is depressed is suddenly released, and a back-shake vibration is generated. There is an inconvenience that it is propagated to the driver and gives anxiety to the driver and deteriorates the ride comfort.

  In addition, in an electric vehicle equipped with an anti-lock braking system (ABS), the braking force is applied to and released from the wheel repeatedly in a short time of several milliseconds. In the connected state, the wheel continues to rotate due to the inertia of the rotor having a large inertial force of the electric motor, the followability of the wheel to the ABS control is deteriorated, the braking distance becomes long, the vehicle spins and the running is disabled. The disadvantage of becoming stable arises.

  SUMMARY OF THE INVENTION An object of the present invention is to make it possible to immediately put a power transmission system into a power cut-off state when an electric motor fails or when an ABS is operated in an electric vehicle using only the electric motor as a drive source.

  In order to solve the above problems, in the present invention, in an electric vehicle in which the drive source is only an electric motor and the vehicle is driven by transmitting the driving force of the electric motor to the wheel, the driving force of the electric motor is applied to the wheel. The power transmission system for transmission includes a drive wheel to which a driving force from the electric motor is input and a driven wheel that outputs the driving force transmitted from the driving wheel to the wheel side. An overrunning type that transmits the driving force of the driving wheel to the driven wheel when the rotational speed of the driving wheel is higher than the rotational speed of the driving wheel, and rotates the driving wheel freely when the rotational speed of the driven wheel becomes faster than the rotational speed of the driving wheel. A configuration incorporating a one-way clutch was adopted.

  In an electric vehicle having the above configuration, if the motor stops due to a failure when the vehicle is running, the one-way clutch automatically overruns when the rotational speed of the driven wheel exceeds the rotational speed of the driving wheel (idle state) ) For this reason, the wheels continue to rotate without being locked, and there is no possibility of being unable to steer or suddenly stopping the vehicle.

  Here, in the electric vehicle equipped with ABS, when braking the wheel by ABS control, the rotation speed of the electric motor is lowered so as to be slower than the minimum value corresponding to the minimum rotation fluctuation of the wheel, or the ABS is stopped by stopping the electric motor. When the control is activated, the one-way clutch is idled and the power transmission system from the electric motor to the wheel is cut off, and the wheel can follow the ABS control well.

  In the electric vehicle according to the present invention, the one-way clutch may be of a roller type, a sprag type, a radial type ratchet type, or an axial type ratchet type.

  The one-way clutch may be incorporated between an electric motor and a transmission that shifts the rotation of the electric motor and transmits the rotation to the wheels, a transmission that shifts the rotation of the electric motor and transmits it to the wheels, and the transmission May be incorporated between the differential that transmits the driving force output from the left and right axles, or between the differential and the axle that transmits the rotation of the electric motor to the left and right axles. Further, it may be incorporated between a pair of left and right axles and wheels connected to each of the axles.

  Here, between the driving wheel and the driven wheel of the one-way clutch, a rotational resistance due to friction is imparted between the driving wheel and the driven wheel when the two wheels rotate relative to each other (at the time of idling). By providing a frictional resistance applying means in which the frictional torque due to the rotational resistance is made smaller than the allowable torque of the one-way clutch, even if the one-way clutch tries to idle due to the deceleration of the motor, the driving wheel and the driven wheel are driven by the frictional resistance applying means. Since constant torque transmission is performed between the two, energy regeneration can be performed using the electric motor as a generator.

  A plurality of outer sides that are axially slidable against the inner periphery of the outer driving wheel located on the outer side of the driving wheel and the driven wheel that are fitted and arranged inside and outside as the frictional resistance applying means. A friction plate and a plurality of axially slidable inner friction plates that are prevented from rotating with respect to the outer periphery of the inner drive wheel are alternately assembled in the axial direction, and both friction plates are brought into elastic contact with each other by pressing of an elastic member. Or an outer cone whose outer peripheral surface is prevented from rotating on the inner periphery of the outer drive wheel and capable of sliding in the axial direction, and whose inner peripheral surface is tapered, and which is prevented from rotating on the outer periphery of the inner drive wheel. And an inner cone whose outer circumferential surface is tapered to match the inner circumferential surface of the outer cone, and the inner cone is urged toward the outer cone by an elastic member. It is possible to adopt things.

  As described above, in the present invention, by incorporating an overrunning type one-way clutch into the power transmission system from the motor to the wheel, the power transmission from the motor to the wheel is immediately interrupted when the motor fails. Can do. For this reason, it is possible to prevent the vehicle from being suddenly stopped due to the wheels being locked and being unable to steer. In addition, the one-way clutch does not require electrical control, so the structure is simple and the cost can be reduced.

  Furthermore, when the wheel is braked by ABS control, the rotation speed of the motor is controlled so that the rotation speed of the motor becomes slower than the minimum value corresponding to the rotation fluctuation of the wheel. Therefore, when the ABS control is activated, the one-way clutch is in the idling state. Thus, the power transmission system from the electric motor to the wheel is cut off, and the wheel can follow the ABS control well.

Schematic plan view showing an embodiment of an electric vehicle according to the present invention (A) is a longitudinal front view of the one-way clutch incorporated in the electric vehicle of FIG. 1, (b) is a sectional view taken along line II-II of (a). Sectional drawing which shows the other example of a one-way clutch Sectional drawing which shows another example of a one-way clutch Sectional drawing which shows another example of a one-way clutch (C) is a front view of the outer ring shown in FIG. 5, (d) is a longitudinal side view of (c). (E) is a front view of the cam plate shown in FIG. 5, and (f) is a plan view of (e). (G) is a development view showing a state where the engaging claw of the cam plate is engaged with the protrusion, and (h) is a development view showing a state where the engagement claw of the cam plate is released from the protrusion. Longitudinal front view of a one-way clutch incorporating frictional resistance applying means Longitudinal front view showing another example of frictional resistance applying means (I) thru | or (k) is a schematic plan view which shows the other example of a one-way clutch incorporating.

  Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, a pair of left and right front wheels 2 is provided at the front of a vehicle body 1 in an electric vehicle, and a pair of left and right rear wheels 3 is provided at the rear.

  An electric motor 10 is mounted on the front of the vehicle body 1, and the rotation of the electric motor 10 is changed by the transmission 11. The rotation of the output shaft of the transmission 11 is transmitted from the front differential 12 to the pair of left and right axles 4. The front wheel 2 rotates.

  Here, the transmission 11 is configured to shift the rotation of the electric motor 10 to one stage. However, a transmission configured to shift to two stages may be employed.

  Between the electric motor 10 and the transmission 11, a one-way clutch 20 that incorporates driving force transmission from the electric motor 10 to the transmission 11 and switching between interruptions is incorporated.

  As shown in FIGS. 2A and 2B, the one-way clutch 20 is a driving wheel in which the rotation from the electric motor 10 is input inside the outer wheel 21 as a driven wheel that outputs rotational torque to the transmission 11. The inner ring 22 is incorporated and supported by a pair of bearings 23 so as to be relatively rotatable. On the outer periphery of the inner ring 22, a wedge space is formed between the inner ring 22 and a cylindrical surface 24 formed on the inner periphery of the outer ring 21. A plurality of cam surfaces 25 are provided at intervals in the circumferential direction, and a roller 26 as an engaging member is provided between each cam surface 25 and the cylindrical surface 24, and the roller 26 is engaged with both the cylindrical surface 24 and the cam surface 25. It is made of an overrunning roller type incorporating an elastic member 27 that urges in the direction of movement.

  The one-way clutch 20 is incorporated so that the roller 26 engages with the cylindrical surface 24 of the outer ring 21 and the cam surface 25 of the inner ring 22 when the electric motor 10 rotates in the direction in which the vehicle travels forward.

  The electric vehicle shown in the embodiment has the above-described structure. Now, when the electric motor 10 is driven, the rotation of the electric motor 10 is transmitted to the inner ring 22, and the inner ring 22 rotates in the direction indicated by the arrow in FIG. The roller 26 is engaged with the cylindrical surface 24 of the outer ring 21 and the cam surface 25 of the inner ring 22, and the one-way clutch 20 is engaged.

  Therefore, the rotation of the inner ring 22 is transmitted to the outer ring 21 via the roller 26, the rotation of the outer ring 21 is changed by the transmission 11, and the rotation output from the transmission 11 is transferred from the front differential 12 to the pair of left and right axles 4. Is transmitted to the front wheel 2 and the vehicle travels forward.

  In general, the vehicle is started at a low speed, but the accelerator pedal may be accidentally depressed strongly, and the depression of the pedal may be released immediately due to the surprise caused by the sudden start. At this time, various driving parts of the power transmission system from the electric motor 10 to the front wheels 2 are greatly twisted by the acceleration torque.

  In particular, the rotor of the electric motor 10 has a large inertial force, and a large twist occurs in the output shaft connected to the rotor, and then the twist is abruptly released.

  At this time, the inner ring 22 connected to the output shaft of the electric motor 10 is rotated in the direction opposite to the arrow shown in FIG. 2B, the roller 26 is displaced to the disengagement position, and the one-way clutch 20 is idled. By the idling, the twist of the output shaft of the electric motor 10 is released, and the vibration of shaking back is suppressed.

  When the rotor support bearing of the motor 10 generating a large amount of heat is burned due to poor lubrication, the battery power is lost, or there is an electrical short circuit when the vehicle is traveling at high speed, the motor 10 decelerates rapidly, or May lock.

  At this time, the one-way clutch 20 is in an overrunning state in which the outer ring 21 to which the rotational torque from the front wheel 2 is transmitted rotates rapidly with respect to the inner ring 22, and the outer ring 21 rotates freely with respect to the inner ring 22.

  For this reason, even if the electric motor 10 decelerates suddenly or locks, the vehicle will continue to coast and will not become unsteerable. In addition, the vehicle does not stop suddenly, and the driver can perform an operation such as stopping the vehicle without his own panic.

  Here, when the ABS is mounted on the electric vehicle, the rotational speed of the electric motor 10 is controlled so that the rotational speed of the electric motor 10 is slower than the average speed of the front wheels 2 when the ABS is operated. Alternatively, the electric motor 10 is stopped. Due to the speed control of the electric motor 10, the outer ring 21 of the one-way clutch 20 rotates faster with respect to the inner ring 22, so that the one-way clutch 20 is in an idling state and power transmission from the electric motor 10 to the front wheel 2 is interrupted. Thus, the front wheel 2 can be accurately ABS controlled. Also, no abnormal noise is generated.

  In the one-way clutch 20 shown in FIG. 2, the cylindrical surface 24 is formed on the inner periphery of the outer ring 21, and the cam surface 25 is provided on the outer periphery of the inner ring 22, but the cam surface is provided on the inner periphery of the outer ring 21. A cylindrical surface may be formed on the outer periphery. Further, although the inner wheel 22 is a driving wheel and the outer wheel 21 is a driven wheel, the outer wheel 21 may be a driving wheel and the inner wheel 22 may be a driven wheel.

  In FIG. 2, the one-way clutch 20 is a roller type, but the one-way clutch 20 is not limited to this. 3 to 8 show other examples of the one-way clutch 20.

  FIG. 3 shows a sprag type one-way clutch 20. In the sprag type one-way clutch 20, cylindrical surfaces 33 and 34 are formed on the inner periphery of the outer ring 31 and the outer periphery of the inner ring 32, and two retainers 35 and 36 having different outer diameters are provided between the cylindrical surfaces 33 and 34. Built-in, a plurality of pockets 37, 38 that are radially opposed to the cages 35, 36 are provided at intervals in the circumferential direction, and a sprag as an engaging element is provided so as to straddle the pockets 37, 38 that are opposed in the radial direction 39, and a pair of cam surfaces 40 and 41 are formed at both ends of the sprag 39 so that the distance between the opposing surfaces increases as the sprag 39 tilts toward one side in the circumferential direction. An elastic member 42 is incorporated in the inner wall 38 to urge the sprag 39 in a direction in which the cam surfaces 40, 41 of the sprag 39 engage with the cylindrical surfaces 33, 34.

  In the one-way clutch 20, when the rotation of the electric motor 10 is transmitted to the inner ring 32 and the inner ring 32 rotates in the direction indicated by the arrow in FIG. 3, the cam surfaces 40 and 41 of the sprag 39 are connected to the outer ring side cylindrical surface 33 and the inner ring. The rotation of the inner ring 32 is transmitted to the outer ring 31 via the sprag 39, and the outer ring 31 rotates in the same direction as the inner ring 32.

  When the rotation speed of the outer ring 31 exceeds the rotation speed of the inner ring 32, the sprag 39 is disengaged and the outer ring 31 rotates freely with respect to the inner ring 32.

  In FIG. 3, the inner ring 32 is a driving wheel and the outer ring 31 is a driven wheel, but the inner ring 32 may be a driven wheel and the outer ring 31 may be a driving wheel.

  FIG. 4 shows a radial type ratchet type one-way clutch 20. In the one-way clutch 20, an inner ring 72 is incorporated inside the outer ring 71, and a plurality of notches 73 are formed in the inner circumference of the outer ring 71 at intervals in the circumferential direction, while a plurality of pockets are formed on the outer circumference of the inner ring 72. 74 is provided at intervals in the circumferential direction, and an engaging claw 75 that can swing in each pocket 74 and an elastic member 76 that urges the engaging claw 75 in a direction to engage with the notch 73 are incorporated. Yes.

  In the one-way clutch 20 configured as described above, one of the outer ring 71 and the inner ring 72 is used as a drive wheel to which power from the electric motor 10 is transmitted, and the other is used to output the driving force transmitted from the drive wheel to the wheel 2 side. Used as a driven wheel. When the inner ring 72 is used as a driving wheel, when the inner ring 72 is rotated in the direction indicated by the arrow in FIG. 4 by driving the electric motor 10, the engaging claw 75 is engaged with the notch 73, and the rotation of the inner ring 72 is transmitted to the outer ring 71. Then, the outer ring 71 rotates in the same direction as the inner ring 72.

  When the rotation speed of the outer ring 71 exceeds the rotation speed of the inner ring 72 in the state of transmission of rotation from the inner ring 72 to the outer ring 71, the engagement claw 75 is disengaged and the outer ring 71 rotates freely with respect to the inner ring 72.

  Here, when the number of the notches 73 is made larger than the number of the engaging claws 75 and the formation pitch of the notches 73 is made different from the mounting pitch of the engaging claws 75, one of the plurality of engaging claws 75 is selected. Since the engagement claw 75 is held in a state of being engaged with the notch 73, there is no play in the rotation direction, and the outer ring 71 can be rotated simultaneously with the rotation of the inner ring 72.

  In FIG. 4, the engaging claw 75 is held by the inner ring 72 and the notch 73 is formed on the inner periphery of the outer ring 71, but the engaging claw 75 is held by forming a pocket on the inner periphery of the outer ring 71. A notch 73 may be formed on the outer periphery.

  5 to 8 show an axial type ratchet type one-way clutch 20. In this one-way clutch 20, an inner ring 82 is incorporated inside the outer ring 81, an inward flange 83 is provided at one end of the outer ring 81, and the other end of the inner ring 82 is outward facing the inward flange 83 in the axial direction. A flange 84 is provided, and the inward flange 83 is provided with a plurality of protrusions 85 having cam surfaces 86 on the outer surface facing the outward flange 84 at equal intervals in the circumferential direction, and the inward flange 83 and the outward flange are provided. A plurality of engaging claws 88 that can be engaged with the protrusions 85 are provided at equal intervals in the circumferential direction on the outer periphery of an annular cam plate 87 incorporated between the opposing surfaces of the protrusions 85. The cam plate 87 is urged by an elastic member 89 made of a wave spring in a direction in which the cam plate 87 is engaged.

  Here, the cam surface 86 formed on the outer periphery of the protrusion 85 is inclined so as to incline with an upward slope in the circumferential direction, as shown in FIGS. 6 (c) and 6 (d) and FIGS. 8 (g) and 8 (h). It comprises a surface 86a, a flat surface 86b connected to the high end edge of the inclined surface 86a, and a step surface 86c connected to the edge of the flat surface 86b. The cam surface 86 is inclined outwardly in the radial direction with a downward gradient, and the inclination angle θ is about 4 °.

  In addition, the engaging claws 88 provided on the outer periphery of the cam plate 87 are inclined with respect to both the front and back surfaces of the cam plate 87 as shown in FIGS. It can be engaged with the surface 86c.

  In the one-way clutch 20 configured as described above, one of the outer ring 81 and the inner ring 82 is used as a driving wheel to which power from the electric motor 10 is transmitted, and the other is used to output the driving force transmitted from the driving wheel to the wheel 2 side. Used as a driven wheel. When the inner ring 82 is used as a driving wheel, when the inner ring 82 rotates in one direction by driving the electric motor 10, the engaging claw 88 engages with the step surface 86 c of the protrusion 85, and the rotation of the inner ring 82 is transmitted to the outer ring 81. Then, the outer ring 81 rotates in the same direction as the inner ring 82.

  When the rotation speed of the outer ring 81 exceeds the rotation speed of the inner ring 82 in the state of transmission of rotation from the inner ring 82 to the outer ring 81, the engaging claw 88 moves in the circumferential direction along the cam surface 86, and the outer ring 81 becomes the inner ring 82. In contrast, it rotates freely.

  Here, when the number of the protrusions 85 is made larger than the number of the engaging claws 88 and the formation pitch of the protrusions 85 is different from the formation pitch of the engagement claws 88, among the plurality of engagement claws 88, Since one engaging claw 88 is disposed at a position that is in contact with or close to the step surface 86 c of the protrusion 85, there is little play in the rotation direction, and the outer ring 81 can be rotated simultaneously with the rotation of the inner ring 82.

  5 to 8, the protrusion 85 is provided on the inward flange 83 of the outer ring 81. However, the protrusion is provided on the outward flange 84 of the inner ring 82, and the cam plate 87 is directed toward the outward flange 84 by the elastic member 89. May be energized.

  9 shows a large-diameter hole 45 formed at the open end of the outer ring 21 in the roller type one-way clutch 20 shown in FIG. 2, and the inner ring 22 has a large-diameter shaft at a position facing the large-diameter hole 45. A portion 46 is provided, and a frictional resistance imparting means 50 is provided between the large diameter shaft portion 46 and the inner diameter surface of the large diameter hole portion 45.

  Here, as the frictional resistance applying means 50, a plurality of outer side friction plates 51 and a plurality of inner side friction plates 52 are alternately assembled in the axial direction, and the outer side friction plates 51 are attached to the inner diameter surface of the large-diameter hole 45. Thus, the inner side friction plate 52 is prevented from rotating on the inner ring 22 as a fitting by the spline 54 with respect to the large-diameter shaft portion 46. The friction plates 51 and 52 are made to be slidable in the axial direction and are brought into elastic contact with each other by the pressing of an elastic member 55 made of a disc spring, so that the outer friction plate 51 and the inner friction plate 52 are contacted with each other. A rotational resistance due to friction is applied between the outer ring 21 and the inner ring 22. Reference numeral 56 denotes a retaining ring for retaining the elastic member 55.

  As described above, by providing the friction resistance applying means 50 including the plurality of friction plates 51 and 52 between the outer ring 21 and the inner ring 22, the friction plate 51, even if the one-way clutch 20 idles due to the decelerated rotation of the electric motor 10. Since 52 groups transmit the rotational torque by friction, the electric motor 10 functions as a generator and can regenerate energy.

  The rotational torque due to the friction of the friction plates 51 and 52 at the time of energy regeneration is set to be smaller than the driving torque of the electric motor 10, that is, the transmittable torque of the one-way clutch 20, and the outer friction plate 51 at the time of fail-safe when the electric motor 10 fails. And the inner friction plate 52 is set to slip.

  Further, by providing the frictional resistance imparting means 50, when the acceleration is started and the acceleration pedal is released and the acceleration is stopped, the driving parts such as the output shaft of the motor that has been twisted by the acceleration torque as described above are provided. The vibration of shaking back is started, but the vibration can be effectively suppressed by the slipping of the one-way clutch 20 and the resistance caused by the friction of the friction plates 51 and 52.

  Further, the resistance caused by the friction of the friction plates 51 and 52 can act as a braking force when the ABS is operated.

  In FIG. 9, the frictional resistance applying unit 50 includes a plurality of friction plates 51 and 52, but the frictional resistance applying unit 50 is not limited to this. For example, as shown in FIG. 10, an outer cone 60 in which an inner peripheral surface 61 is tapered between a large-diameter hole portion 45 and a large-diameter shaft portion 46, and an outer peripheral surface 63 is a tapered inner peripheral surface of the outer cone 60. An inner cone 62 having a tapered shape that fits 61 is incorporated, and the outer cone 60 is fitted to the large-diameter hole 45 by a spline 53 to prevent the outer ring 21 from rotating, and the inner cone 62 is slidable in the axial direction. The nakone 62 is fitted to the large-diameter shaft portion 46 by the spline 54 so as to be prevented from rotating on the inner ring 22 and slidable in the axial direction, and the inner cone 62 is urged toward the outer cone 60 by the pressing of the elastic member 64. It may be as described above.

  In the embodiment shown in FIG. 1, the one-way clutch 20 is incorporated between the electric motor 10 and the transmission 11, but the assembling position of the one-way clutch 20 is not limited to this.

  FIGS. 11I to 11K show other examples of incorporating the one-way clutch 20. In (i), a one-way clutch 20 is incorporated between the transmission 11 and the front differential 12.

  (J) incorporates a one-way clutch 20 between each of the pair of left and right axles 4 and the front differential 12.

  In (k), a one-way clutch 20 is incorporated between each of the pair of left and right axles 4 and the front wheel 2.

2 Front wheels
4 Axle 10 Electric motor 11 Transmission 12 Front differential (differential)
20 One-way clutch 21 Outer ring 22 Inner ring 24 Cylindrical surface 25 Cam surface 26 Roller (engagement element)
27 elastic member 31 outer ring 32 inner ring 33 cylindrical surface 34 cylindrical surface 35 cage 36 cage 37 pocket 38 pocket 39 sprag 40 cam surface 41 cam surface 42 elastic member 50 friction resistance applying means 51 outer side friction plate 52 inner side friction plate 60 Outer cone 61 Inner peripheral surface 62 Inner cone 63 Outer peripheral surface 71 Outer ring 72 Inner ring 73 Notch 74 Pocket 75 Engaging claw 76 Elastic member 81 Outer ring 82 Inner ring 83 Inward flange 84 Outward flange 85 Projection 86 Cam surface 86a Inclined surface 86b Flat surface 86c Stepped surface 87 Cam plate 88 Engaging claw 89 Elastic member

Claims (16)

In an electric vehicle in which the drive source is only an electric motor and the vehicle is driven by transmitting the driving force of the electric motor to wheels,
In the power transmission system that transmits the driving force of the electric motor to the wheel, the driving wheel that receives the driving force from the electric motor and the driven wheel that outputs the driving force transmitted from the driving wheel to the wheel side, When the rotational speed of the driving wheel is faster than the rotational speed of the driven wheel, the driving force of the driving wheel is transmitted to the driven wheel, and when the rotational speed of the driven wheel becomes faster than the rotational speed of the driving wheel, the driving wheel An electric vehicle that incorporates an overrunning one-way clutch that rotates the wheel freely.   The one-way clutch is provided with a plurality of cam surfaces that form a cylindrical surface on one side of the inner periphery of the outer ring and the outer periphery of the inner ring that is incorporated inside the outer ring, and on the other side, a wedge space that forms a wedge space. A roller type that incorporates a roller between a cam surface and a cylindrical surface and an elastic member that urges the roller in a direction to engage both the cylindrical surface and the cam surface. One of the outer ring and the inner ring is a driving wheel. The electric vehicle according to claim 1, wherein the other is a driven wheel.   The one-way clutch forms a cylindrical surface on the inner periphery of the outer ring and the outer periphery of the inner ring incorporated inside, and forms a plurality of pockets in the circumferential direction of the cage assembled between the outer ring cylindrical surface and the inner ring cylindrical surface. The sprag is of a sprag type that incorporates a sprag in each pocket and an elastic member that urges the sprag in a direction to engage both the outer ring cylindrical surface and the inner ring cylindrical surface. One of the outer ring and the inner ring is a drive wheel. The electric vehicle according to claim 1, wherein the other is a driven wheel.   The one-way clutch is formed with a plurality of pockets spaced in the circumferential direction on one of the inner periphery of the outer ring and the outer periphery of the inner ring incorporated therein, and a plurality of notches provided in the circumferential direction on the other. A radial ratchet type incorporating an engaging claw swingable in the pocket and an elastic member that urges the engaging claw in a direction to engage the notch, and the outer ring and the inner ring The electric vehicle according to claim 1, wherein one is a driving wheel and the other is a driven wheel.   The electric vehicle according to claim 4, wherein the number of the notches is made larger than the number of the engaging claws, and the notch forming pitch is different from the mounting pitch of the engaging claws.   The one-way clutch is provided with an inward flange at one end of the outer ring, and an outward flange that is axially opposed to the inward flange is formed at the other end of the inner ring incorporated inside the outer ring. And a cam surface in which a flat surface is connected to the edge of the inclined surface inclined upwardly in the circumferential direction, and a step surface is connected to the edge of the flat surface. A plurality of protrusions having an outer periphery are provided in the circumferential direction, and the cam surface of each protrusion is inclined downwardly in the radial direction and is incorporated between the facing portions of the inward flange and the outward flange. An axial type in which a plurality of engaging claws that can be engaged with the stepped surface are formed on the outer periphery of the cam plate, and the cam plate is urged toward the flange on the side where the protrusion is formed by an elastic member. Is it a ratchet type? Becomes, and the outer ring and one of the driving wheels of the inner ring, an electric vehicle according to claim 1 in which the other is a driven wheel.   The electric vehicle according to claim 6, wherein the number of the protrusions is greater than the number of the engaging claws, and the formation pitch of the protrusions is different from the formation pitch of the engagement claws.   Friction resistance imparting means for imparting rotational resistance due to friction between the driving wheel and the driven wheel between the driving wheel and the driven wheel of the one-way clutch in the radial direction is provided, The electric vehicle according to any one of claims 1 to 7, wherein a friction torque of the frictional resistance applying means is smaller than an allowable torque of the one-way clutch.   The frictional resistance applying means includes a plurality of outer side friction plates slidable in the axial direction that are prevented from rotating with respect to an inner periphery of an outer driving wheel located on the outer side of the driving wheel and the driven wheel, and the inner side A plurality of axially slidable inner friction plates that are prevented from rotating with respect to the outer periphery of the drive wheel are alternately assembled in the axial direction, and the friction plates are in elastic contact with each other by pressing of an elastic member. Item 9. The electric vehicle according to Item 8.   Outer cone in which the frictional resistance imparting means is prevented from rotating on the inner periphery of the outer driving wheel located on the outer side of the driving wheel and the driven wheel and is slidable in the axial direction, and the inner peripheral surface is tapered. And an inner cone whose outer periphery is prevented from rotating on the outer periphery of the inner drive wheel and is axially slidable and whose outer peripheral surface is tapered to match the tapered inner peripheral surface of the outer cone, and the inner cone is used as the outer cone. The electric vehicle according to claim 8, comprising an elastic member that presses toward the electric vehicle.   The electric vehicle according to any one of claims 8 to 10, wherein a regenerative braking force when the electric motor operates as a generator is smaller than a rotational resistance caused by friction of the frictional resistance applying means.   The electric vehicle according to any one of claims 1 to 11, wherein the one-way clutch is incorporated between the electric motor and a transmission that shifts the rotation of the electric motor and transmits it to a wheel.   12. The one-way clutch is incorporated between a transmission that shifts the rotation of the electric motor and transmits it to a wheel, and a differential that transmits a driving force output from the transmission to left and right axles. The electric vehicle according to any one of the items.   The electric vehicle according to any one of claims 1 to 11, wherein the way clutch is incorporated between a differential for transmitting rotation of the electric motor to left and right axles and the axle.   The electric vehicle according to any one of claims 1 to 11, wherein the one-way clutch is incorporated between a pair of left and right axles and a wheel connected to each of the axles.   16. The motor according to claim 1, wherein when the wheel is braked by ABS control, the rotation speed of the motor is controlled so that the rotation speed of the motor becomes slower than the minimum value corresponding to the minimum rotation fluctuation of the wheel. Electric car.

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