Electric vehicle and control method for electric vehicle drive unit

Abstract

When the electric vehicle 1 starts moving from a parked state or during deceleration control, the clutch input member 12 and the clutch output member 13 alternately alternate in a short period of time between an unlocked state in which torque can be transmitted between the clutch input member 12 and the clutch output member 13 and a locked state in which torque cannot be transmitted, preventing the occurrence of a phenomenon in which the clutch input member 12 and the clutch output member 13 rotate intermittently. 13 The direction of the rotation of the clutch input member 12 connected to the drive motor 4 side is the same as the direction of the rotation of the reverse input torque T 13 When the magnitude of the reverse input torque T is within a predetermined range in which the above phenomenon can occur, 13 The braking device 7 generates or increases the braking force so that the magnitude of the force is less than the lower limit of the predetermined range.

Description

[Technical Field]

[0001] The present disclosure relates to an electric vehicle using an electric motor as a drive source, and a control method for a drive device for an electric vehicle. [Background technology]

[0002] In response to the recent trend toward reducing the use of fossil fuels, research into electric vehicles has progressed and some electric vehicles have been put into practical use. For example, Japanese Patent Application Laid-Open No. 2000-10631 describes an electric vehicle equipped with a drive motor for each running wheel.

[0003] The electric vehicle described in JP 2000-10631 A uses an electric motor as the drive motor, which has a parking brake function to prevent the vehicle from moving when parked, regardless of external forces or the inclination angle of the road surface.

[0004] WO 2023 / 085395 describes a reverse input disconnection clutch that can be used as a parking brake. The reverse input disconnection clutch described in WO 2023 / 085395 includes a pressed member, a clutch input member, a clutch output member, and an engagement element.

[0005] In the reverse input cut-off clutch described in WO 2023 / 085395, when rotational torque is input to the clutch input member, the input-side engaging portion of the clutch input member engages with the input-side engaged portion of the engager, causing the engager to move radially inward and engage the output-side engaged portion of the engager with the output-side engaging portion of the clutch output member, thereby transmitting the rotational torque input to the clutch input member to the clutch output member. On the other hand, when rotational torque is reversely input to the clutch output member, the engager moves radially outward, causing a pressing surface of the engager to be pressed against the pressed surface, and the pressing surface frictionally engages with the pressed surface.

[0006] By connecting the clutch input member constituting such a reverse input cutoff clutch to the drive motor side of the electric vehicle described in JP 2000-10631 A and connecting the clutch output member to the wheel side, it is possible to prevent the vehicle from moving when parking, regardless of external forces or the inclination angle of the road surface. In other words, the reverse input cutoff clutch constitutes a parking brake. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-10631 [Patent Document 2] International Publication No. 2023 / 085395 Summary of the Invention [Problem to be solved by the invention]

[0008] However, if the reverse input cut-off clutch described in International Publication No. 2023 / 085395 is applied to the parking brake provided on each running wheel of the electric vehicle described in Patent Publication No. 2000-10631, the behavior of the electric vehicle may become unstable when it starts running or when it decelerates.

[0009] For example, when the vehicle is parked on a slope, a rotational torque in a predetermined direction is input in reverse from the drive wheels to the clutch output member. When rotational torque in the predetermined direction is input from the drive motor to the clutch input member to start traveling downhill from this state, there is a possibility that a phenomenon will occur in which the clutch input member and the clutch output member intermittently rotate in the predetermined direction while alternately repeating in a short period of time an unlocked state in which torque can be transmitted between the clutch input member and the clutch output member and a locked state in which torque cannot be transmitted between the clutch input member and the clutch output member.

[0010] This phenomenon can also occur when deceleration control is being performed to stop an electric vehicle, and an imbalance between the inertial force acting on the drive wheels and the force due to running resistance or the like causes a rotational torque to be input inversely from the drive wheels to the clutch output member.

[0011] When this phenomenon occurs, the rotation of the drive wheels becomes unsmooth, which may cause the behavior of the electric vehicle to become unstable, and the reverse input cutoff clutch may become more susceptible to wear.

[0012] The present disclosure aims to realize a control method for an electric vehicle and a drive unit for an electric vehicle that can prevent the occurrence of a phenomenon in which the clutch input member and the clutch output member rotate intermittently by alternately repeating in a short period of time an unlocked state in which torque can be transmitted and a locked state in which torque cannot be transmitted. [Means for solving the problem]

[0013] The inventors of the present disclosure have conducted extensive research into the conditions under which a reverse input cut-off clutch in a drive unit of an electric vehicle intermittently rotates between an unlocked state in which torque can be transmitted and a locked state in which torque cannot be transmitted, and as a result have discovered that the phenomenon occurs when, in a state in which torque is reversely input to the clutch output member in a predetermined direction, the rotational speed of the clutch input member in the predetermined direction is less than a predetermined threshold (a rotational speed sufficient to prevent the phenomenon from occurring) and the magnitude of the torque reversely input to the clutch output member is within a predetermined range (a range in which the phenomenon can occur).An electric vehicle according to one aspect of the present disclosure and a control method for an electric vehicle drive unit according to one aspect of the present disclosure have been completed based on this finding.

[0014] An electric vehicle according to one aspect of the present disclosure includes a drive unit and a control unit.

[0015] The drive unit includes a drive motor, drive wheels, a reverse input cutoff clutch, and a braking device.

[0016] The reverse input disconnect clutch has a clutch input member connected to the drive motor side and a clutch output member connected to the drive wheels side. The reverse input disconnect clutch transmits torque input to the clutch input member from the drive motor side to the clutch output member, but does not transmit torque reversely input to the clutch output member from the drive wheels side to the clutch input member.

[0017] The braking device is disposed on the drive wheel side of the reverse input cutoff clutch in a torque transmission path from the drive motor to the drive wheels, and applies a braking force to the drive wheels.

[0018] The control device controls the drive motor and the braking device.

[0019] In particular, in an electric vehicle according to one aspect of the present disclosure, when the direction of reverse input torque, which is the rotational torque reversely input from the drive wheel side to the clutch output member, is the same as the rotational direction of the clutch input member connected to the drive motor side, and the magnitude of the reverse input torque is within a predetermined range, the control device generates or increases braking force using the braking device so that the magnitude of the reverse input torque is less than the lower limit of the predetermined range, preferably zero.

[0020] More specifically, in an electric vehicle according to one aspect of the present disclosure, when the electric vehicle starts traveling from a parked state in a direction that rotationally drives the clutch input member in the same direction as the direction of the reverse input torque, which is the rotational torque that is reversely input to the clutch output member, if the magnitude of the reverse input torque is within a predetermined first range, the control device can have a first function of rotating the clutch input member using the drive motor while generating the braking force so that the magnitude of the reverse input torque can be less than the lower limit of the first range, and releasing the braking force when the rotational speed of the clutch input member becomes equal to or greater than a predetermined first threshold value.

[0021] In the electric vehicle according to one aspect of the present disclosure, the braking force can be set to a magnitude that makes the magnitude of the reverse input torque zero.

[0022] In an electric vehicle according to one embodiment of the present disclosure, the control device can have a second function of, when deceleration control is being executed, the rotation speed of the clutch input member is equal to or less than a predetermined second threshold, the direction of the reverse input torque is the same as the rotation direction of the clutch input member, and the magnitude of the reverse input torque is within a predetermined second range, increasing the braking force by an amount that makes the magnitude of the reverse input torque less than the lower limit of the second range, and then continuing the deceleration control.

[0023] In the electric vehicle according to one aspect of the present disclosure, the amount by which the braking force is increased can be set to an amount that makes the magnitude of the reverse input torque zero.

[0024] In the electric vehicle according to one aspect of the present disclosure, the drive motor can be controlled by speed control or position control while the second function is being executed.

[0025] In an electric vehicle according to one embodiment of the present disclosure, the control device can control the drive motor by torque control while executing the second function, and can increase the braking force while simultaneously increasing the magnitude of the rotational torque input to the clutch input member by an amount corresponding to the decrease in the reverse input torque based on the increase in the braking force.

[0026] In an electric vehicle according to one aspect of the present disclosure, The reverse input cutoff clutch is a pressed member having a pressed surface on its inner circumferential surface; the clutch input member having an input side engaging portion arranged radially inside the pressed surface and arranged coaxially with the pressed surface; the clutch output member having an output side engaging portion disposed radially inward of the input side engaging portion on the radially inner side of the pressed surface, the output side engaging portion being disposed coaxially with the pressed surface; an engaging element having a pressing surface facing the pressed surface, an input side engaged portion engageable with the input side engaging portion, and an output side engaged portion engageable with the output side engaging portion, and being disposed so as to be movable in a radial direction; It can be equipped with:

[0027] In this case, when rotational torque is input to the clutch input member, the engaging element moves radially inward based on the engagement of the input side engaging portion with the input side engaged portion, and by engaging the output side engaged portion with the output side engaging portion, the rotational torque input to the clutch input member is transmitted to the clutch output member, whereas when rotational torque is input in the reverse direction to the clutch output member, the output side engaging portion engages with the output side engaged portion, and the pressing surface is pressed against the pressed surface, causing the pressing surface to frictionally engage with the pressed surface.

[0028] In the electric vehicle according to one aspect of the present disclosure, the pressing surface can be configured by two pressing surfaces.

[0029] In this case, when the two pressing surfaces are pressed against the pressed surface as the clutch output member rotates, and when the clutch input member rotates in the direction opposite to the rotational direction of the clutch output member, and the input side engaging portion and the input side engaged portion are engaged, the distance between the contact portion between the input side engaging portion and the input side engaged portion and the center of rotation of the clutch input member in a second direction perpendicular to both a first direction in which the pressing surface moves away from the pressed surface and a second direction in which the center of rotation of the clutch input member is perpendicular is smaller than the distance between the contact portion between the output side engaging portion and the output side engaged portion and the center of rotation of the clutch output member in the second direction, When a rotational torque is input in reverse to the clutch output member and the two pressing surfaces are in contact with the pressed surface, the contact portion between the output side engaging portion and the output side engaged portion can be located closer to the center of rotation of the clutch output member in the first direction than an imaginary line connecting the abutment portion between one of the two pressing surfaces and the pressed surface and the center of rotation of the clutch output member.

[0030] In the electric vehicle according to one aspect of the present disclosure, the reverse input disconnection clutch may include a biasing member that elastically biases the engagement element radially outward.

[0031] An electric vehicle drive device that is a target of a control method for an electric vehicle drive device according to one aspect of the present disclosure includes: A drive motor; Drive wheels and a reverse input cutoff clutch having a clutch input member connected to the drive motor side and a clutch output member connected to the drive wheel side, which transmits torque input to the clutch input member from the drive motor side to the clutch output member, but does not transmit torque reversely input to the clutch output member from the drive wheel side to the clutch input member; a braking device that is disposed on the drive wheel side of the reverse input cutoff clutch in a torque transmission path from the drive motor to the drive wheels and that applies a braking force to the drive wheels; Equipped with.

[0032] In one embodiment of the control method for an electric vehicle drive device disclosed herein, when the direction of reverse input torque, which is the rotational torque reversely input from the drive wheel side to the clutch output member, is the same as the rotational direction of the clutch input member connected to the drive motor side, and the magnitude of the reverse input torque is within a predetermined range, the braking device generates or increases braking force so that the magnitude of the reverse input torque is less than the lower limit of the predetermined range, preferably to zero.

[0033] In one aspect of the present disclosure, there is provided a control method for an electric vehicle drive device, comprising: When starting to travel from a parked state in a direction that rotates the clutch input member in the same direction as the direction of the reverse input torque, which is the rotational torque that is reversely input to the clutch output member, if the magnitude of the reverse input torque is within a predetermined first range, the braking force is generated so that the magnitude of the reverse input torque can be made less than the lower limit of the first range, and after the clutch input member is rotationally driven by the drive motor, the braking force is released when the rotation speed of the clutch input member becomes equal to or greater than a predetermined first threshold value.

[0034] In one aspect of the present disclosure, there is provided a control method for an electric vehicle drive device, comprising: During execution of deceleration control, when the rotation speed of the clutch input member is equal to or less than a predetermined second threshold, the direction of the reverse input torque, which is the rotational torque that is reversely input to the clutch output member, is the same as the rotation direction of the clutch input member, and the magnitude of the reverse input torque is within a predetermined second range, the braking force is increased by an amount that makes the magnitude of the reverse input torque less than the lower limit of the second range, and then the deceleration control is continued. [Effects of the Invention]

[0035] According to an electric vehicle according to one aspect of the present disclosure and a control method for an electric vehicle drive device according to one aspect of the present disclosure, it is possible to prevent the occurrence of a phenomenon in which the clutch input member and the clutch output member rotate intermittently by alternately repeating in a short period of time an unlocked state in which torque can be transmitted and a locked state in which torque cannot be transmitted. [Brief explanation of the drawings]

[0036] [Figure 1] FIG. 1 is a plan view schematically showing an electric vehicle according to a first embodiment of the present disclosure. [Figure 2] FIG. 2 is an end view of a reverse input cutoff clutch of a drive unit constituting an electric vehicle, viewed from the clutch output member side. [Figure 3] 3 is a side view seen from the cross section taken along line XX in FIG. 2. FIG. [Figure 4]FIG. 4 is a cross-sectional view taken along line YY of FIG. 3, with the biasing member omitted. [Figure 5] FIG. 5 is a view similar to FIG. 4, showing a state in which rotational torque is input to the clutch input member. [Figure 6] FIG. 6 is a view similar to FIG. 4, showing a state in which a rotational torque is reversely input to the clutch output member. [Figure 7] FIG. 7 is a flowchart showing the operation of the first function. [Figure 8] FIG. 8 is a flowchart showing the operation of the second function. [Figure 9] FIG. 9 shows an example of a region where, when an electric vehicle starts to travel, the clutch input member and the clutch output member intermittently rotate while alternately repeating in a short period of time an unlocked state in which torque can be transmitted and a locked state in which torque cannot be transmitted. [Figure 10] FIG. 10 is a diagram showing an example of a region where the above phenomenon occurs during deceleration of an electric vehicle. [Figure 11] FIG. 11 is a flowchart showing the operation of the second function in the second example of the embodiment of the present disclosure. [Figure 12] FIG. 12 is a plan view schematically illustrating an electric vehicle according to a third example of an embodiment of the present disclosure. [Figure 13] FIG. 13 is a plan view schematically illustrating an electric vehicle according to a fourth example of an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0037] [Example 1] A first example of an embodiment of the present disclosure will be described with reference to FIGS.

[0038] An electric vehicle to which the present disclosure is applicable is a vehicle that uses electricity as an energy source and is driven by an electric motor. The present disclosure can be widely applied to electric vehicles, and can be applied not only to self-driving vehicles but also to electric vehicles operated by humans. Self-driving vehicles include automated guided vehicles and robotic cars used in industrial applications, as well as autonomous buses, taxis, and passenger cars that can be used on public roads and transport passengers. In this example, the present disclosure is installed in an automated guided vehicle that transports goods in a factory, warehouse, or the like.

[0039] <Overall structure of electric vehicle> The electric vehicle 1 includes a drive unit 2 and a control device 3. The drive unit 2 includes a drive motor 4, drive wheels 5, a reverse input cutoff clutch 6, and a braking device 7. The number of drive units 2 is determined appropriately depending on the type of electric vehicle 1, etc. Therefore, the electric vehicle 1 can include one or more drive units 2. The electric vehicle 1 can also include one or more non-drive wheels other than the drive wheels 5. The electric vehicle 1 in this example includes four drive units 2 and no non-drive wheels.

[0040] The drive motor 4 is an element for driving and rotating the drive wheels 5, and is configured by an electric motor that can be controlled by at least one of position control, speed control, and torque control. Examples of such electric motors include a servo motor and a stepping motor.

[0041] The drive wheels 5 are rotationally driven by the drive motor 4 via a reverse input cutoff clutch 6. The drive unit 2 can include one drive wheel 5 or multiple drive wheels 5. That is, the drive unit 2 can be configured to rotate one drive wheel 5 using one drive motor 4. Alternatively, the drive unit 2 can be configured to rotate multiple drive wheels 5 using one drive motor 4. In this example, each of the four drive units 2 includes one drive wheel 5.

[0042] The reverse input cutoff clutch 6 has a clutch input member 12 connected to the drive motor 4 side and a clutch output member 13 connected to the drive wheels 5 side. The reverse input cutoff clutch 6 transmits torque input from the drive motor 4 side to the drive wheels 5 side, but does not transmit torque reversely input from the drive wheels 5 side to the drive motor 4 side. The reverse input cutoff clutch 6 is configured to transmit torque input to the clutch input member 12 to the clutch output member 13, but not to transmit torque reversely input to the clutch output member 13 to the clutch input member 12. In other words, the reverse input cutoff clutch 6 is disposed in the torque transmission path from the drive motor 4 to the drive wheels 5, and the clutch input member 12 is directly or indirectly connected to the drive motor 4 and is rotationally driven by the drive motor 4. The clutch output member 13 is directly or indirectly connected to the drive wheels 5.

[0043] The structure of the reverse input cutoff clutch 6 is arbitrary as long as it is applicable to the parking brake, and a known structure such as the reverse input cutoff clutch described in WO 2023 / 085395 can be adopted.

[0044] The drive units 2 are supported directly or indirectly on the vehicle body 9. In this example, the four drive units 2 are supported at four locations on the front, rear, left and right sides of the vehicle body 9.

[0045] The braking device 7 is disposed on the driving wheel 5 side of the reverse input cutoff clutch 6 in the torque transmission path from the driving motor 4 to the driving wheels 5, and applies braking force to the driving wheels 5. The braking device 7 is configured to be able to adjust the braking force. The braking device 7 generates braking force to slow down the rotation of the driving wheels 5 when the electric vehicle 1 is traveling, but does not generate braking force when the electric vehicle 1 is parking.

[0046] The type of braking device 7 is not particularly limited as long as it is possible to adjust the braking force. The braking device 7 can be configured, for example, by a friction brake such as a disc brake or a drum brake.

[0047] The control device 3 controls the drive motor 4 and the braking device 7. The electric vehicle 1 can be equipped with one control device 3 to control one or more drive devices 2. However, the electric vehicle 1 can also be equipped with two or more control devices 3, with each control device 3 controlling each drive device 2.

[0048] Specifically, the control device 3 controls the direction of travel, driving speed, acceleration, and turning angle of the electric vehicle 1 by adjusting at least one of the rotation direction, rotation speed, and output torque of the drive motor 4 of the drive device 2, as well as the braking force of the brake device 7.

[0049] The drive unit 2 of this example may further include, as an optional component, a reducer 10 arranged in a torque transmission path from the drive motor 4 to the drive wheels 5. The reducer 10 reduces the speed of the output rotation of the drive motor 4 (increases the output torque) and transmits it to the drive wheels 5.

[0050] There are no particular limitations on the type of reducer 10. The reducer 10 can be configured, for example, as a planetary gear reducer, a parallel shaft gear reducer, a friction roller reducer, a multi-speed transmission or a continuously variable transmission that can change the reduction ratio, or the like.

[0051] In this example, the reducer 10 can be arranged in the torque transmission path from the drive motor 4 to the drive wheels 5, between the drive motor 4 and the reverse input cutoff clutch 6, or between the reverse input cutoff clutch 6 and the drive wheels 5. The electric vehicle 1 in this example is equipped with the reducer 10, and the reducer 10 is arranged between the reverse input cutoff clutch 6 and the drive wheels 5.

[0052] <Function to prevent the occurrence of a phenomenon in which the clutch input member and the clutch output member rotate intermittently in a reverse input disconnect clutch> The electric vehicle 1 has a function to prevent the occurrence of a phenomenon that may occur due to the provision of the reverse input cut-off clutch 6, in which the clutch input member 12 and the clutch output member 13 intermittently rotate while alternately repeating in a short period of time an unlocked state in which torque can be transmitted between the clutch input member 12 and the clutch output member 13 and a locked state in which torque cannot be transmitted when starting to travel downhill from a state in which the electric vehicle is parked on a slope or when decelerating to stop.

[0053] In the electric vehicle 1, as one of such functions, the control device 3 controls the reverse input torque T 13 The direction of the rotation of the clutch input member 12 connected to the drive motor 4 side is the same as the direction of the rotation of the reverse input torque T 13 When the magnitude of the reverse input torque T 13 The braking device 7 generates or increases the braking force so that the magnitude of the force is less than the lower limit of the predetermined range, preferably to zero.

[0054] The predetermined range is a range in which the above phenomenon can occur in the reverse input cutoff clutch 6. The lower limit of the predetermined range can be determined by experiment, calculation, simulation, or the like.

[0055] More specifically, as a first function, the control device 3 controls the clutch input member 12 from the parking state to rotate in a reverse input torque T 13 When starting to move in the direction of rotation, the reverse input torque T 13 When the magnitude of the reverse input torque T is within a predetermined first range, the brake device 7 13 With braking force F generated so that the magnitude of braking force F can be made less than the lower limit of the first range, clutch input member 12 is driven to rotate by drive motor 4, and when the rotation speed of clutch input member 12 reaches or exceeds a predetermined first threshold, the braking force applied by braking device 7 is released.

[0056] As an additional or alternative second function, the control device 3 is configured to: 13 The direction of the rotation of the clutch input member 12 is the same as the direction of the rotation of the reverse input torque T 13 When the magnitude of the reverse input torque T is within a predetermined second range, the braking force by the braking device 7 is 13 is increased by an amount that can make it less than the lower limit of the second range, and then the deceleration control is continued.

[0057] In the electric vehicle 1, the control device 3 can have either the first function or the second function, or both the first function and the second function.

[0058] (First function) The first function is to reduce the rotational torque (reverse input torque) T 13 The first function is executed when the direction of rotation of the electric vehicle 1 coincides with the direction of the rotational torque input to the clutch input member 12 when the drive motor 4 is started to start the electric vehicle 1 so as to start traveling down the slope. That is, the first function is executed when the clutch input member 12 is rotationally driven by the drive motor 4 so as to start traveling down the slope from a state in which the electric vehicle 1 is parked on the slope.

[0059] The rotational torque (reverse input torque) T that is reversely input to the clutch output member 13 in the parking state 13 This can be obtained by measuring parameters such as the inclination and weight of the electric vehicle 1 in a parked state using sensors for acquiring these parameters, and estimating the direction and magnitude of the rotational moment acting on the drive wheels 5.

[0060] The predetermined first threshold value is a rotation speed of the clutch input member 12 that is sufficient to prevent the occurrence of the above phenomenon in the reverse input cutoff clutch 6. In other words, when the rotation speed of the clutch input member 12 is equal to or greater than the first threshold value, the rotation speed of the clutch output member 13 and the rotational torque (reverse input torque) T13 The first threshold value is determined in advance by experiment, calculation, simulation, or the like.

[0061] The predetermined first range is a range of the magnitude of the reverse input torque of the clutch output member 13 in which the above phenomenon can occur in the reverse input cutoff clutch 6. In other words, the rotational torque (reverse input torque) T 13 If the magnitude of is outside the first range, the above phenomenon does not occur regardless of the rotation speed or rotational torque of clutch input member 12 or the rotation speed of clutch output member 13. The first range varies depending on the structure of reverse input disconnection clutch 6, and the dimensions and shapes of the elements that make up reverse input disconnection clutch 6, including clutch input member 12 and clutch output member 13. The first range is determined in advance by experiment, calculation, simulation, etc.

[0062] The first range can be determined experimentally, for example, as follows: A first electric motor is connected to clutch input member 12, and a second electric motor is connected to clutch output member 13. A rotational torque of a predetermined magnitude is applied to clutch output member 13 in a predetermined direction by the second electric motor. In this state, the first electric motor starts to rotate clutch input member 12 in the predetermined direction at a predetermined rotational acceleration, and it is visually observed whether the above-mentioned phenomenon occurs in reverse input disconnect clutch 6.

[0063] Such an experiment is carried out multiple times while changing the rotational acceleration of the clutch input member 12 and the magnitude of the rotational torque applied to the clutch output member 13. By carrying out such an experiment, it is possible to determine the reverse input torque T 13 The first range of magnitude (T min ≦T 13 ≦T max ), i.e., the lower bound T min and upper bound T max Ask for.

[0064] FIG. 9 shows the rotational torque [Nm] applied to the clutch output member 13 on the horizontal axis, and the rotational acceleration [rps 2 An example of a region where the above phenomenon occurs is shown on a graph with the vertical axis representing [value].

[0065] While not limited to this, an example of the operation of the first function executed when the electric vehicle 1 starts traveling from a parked state, i.e., a state in which the rotation of the drive wheels 5 is locked by the reverse input cut-off clutch 6, will be described in more detail below with reference to FIG. 7.

[0066] First, in S1-1, the reverse input torque T 13 Get the direction and magnitude of the

[0067] Reverse input torque T 13 There is no particular limitation on the method for obtaining the direction and magnitude of the reverse input torque T 13 The direction and magnitude of the reverse input torque T can be determined based on output signals from various sensors mounted on the vehicle body 9. The sensors detect the physical conditions inside and outside the vehicle, convert them into electrical signals, and send them to the control device 3. Examples of sensors include, but are not limited to, a gyro sensor for detecting the inclination angle of the vehicle body 9, a weight sensor for detecting the weight of a transported object, and a torque sensor for measuring the rotational torque of the clutch output member 13 or a member disposed between the clutch output member 13 and the drive wheels 5. In other words, the inclination angle of the road surface determined based on the output signal of the gyro sensor and the direction and magnitude of the rotational moment acting on the drive wheels 5 can be estimated based on the output signal of the weight sensor. 13 Alternatively, the driving device 2 can obtain the direction and magnitude of the reverse input torque T based on the output of the torque sensor. 13 The direction and magnitude of the

[0068] Next, in S1-2, the reverse input torque T 13is the same as the direction in which the clutch input member 12 should be rotationally driven to make the electric vehicle 1 travel in a desired direction. Specifically, when the electric vehicle 1 is parked on a slope and starts to move down the slope, the reverse input torque T 13 The direction of rotation of the clutch input member 12 is the same as the direction in which the clutch input member 12 is to be rotationally driven.

[0069] In S1-2, the reverse input torque T 13 If it is determined that the direction in which the clutch input member 12 should be rotationally driven is different from the direction in which the reverse input cutoff clutch 6 should be rotationally driven, there is no possibility that the above phenomenon will occur in the reverse input cutoff clutch 6, so the process proceeds to S1-8, the drive motor 4 is started, and the clutch input member 12 is rotationally driven in the desired direction, thereby starting the electric vehicle 1 to travel, and then the operation of the first function is terminated.

[0070] In S1-2, the reverse input torque T 13 If it is determined that the direction of rotation of the clutch input member 12 is the same as the direction in which the clutch input member 12 should be rotated, the process proceeds to S1-3, and the reverse input torque T 13 The size of is within a predetermined range (T min ≦T 13 ≦T max ) is determined.

[0071] In S1-3, the reverse input torque T 13 The magnitude of the reverse input torque T is outside the specified range. 13 The size of the lower limit T min smaller than (T 13 <T min ), or greater than the upper limit (T 13 >T max ), there is no possibility that the above phenomenon will occur in the reverse input cutoff clutch 6, so the process proceeds to S1-8, the drive motor 4 is started, and the clutch input member 12 is rotationally driven in the desired direction, causing the electric vehicle 1 to start traveling, and then the operation of the first function is terminated.

[0072] In S1-3, the reverse input torque T 13The magnitude of is within a predetermined range (T min ≦T 13 ≦T max ) is determined, proceed to S1-4.

[0073] In S1-4, the brake device 7 applies a reverse input torque T 13 The magnitude of the first range is the lower limit T min In this example, the braking device 7 exerts a braking force F so that the reverse input torque T 13 0. As a result, the clutch output member 13 exerts a braking force F of a magnitude that can reduce the magnitude of the reverse input torque T 13 The magnitude of is less than the lower limit of the first range, preferably 0.

[0074] Next, in S1-5, the drive motor 4 is started to rotate the clutch input member 12, and the rotational speed (rotational velocity) of the drive motor 4 is increased to increase the rotational speed of the clutch input member 12, thereby causing the electric vehicle 1 to start running, and the process proceeds to S1-6.

[0075] In S1-6, the rotation speed R of the clutch input member 12 in is a given threshold R j That's all (R in ≧R j ) is determined. in can be obtained based on the output of a rotation sensor that measures the rotation speed of the clutch input member 12 or a member disposed between the clutch input member 12 and the drive motor 4.

[0076] In S1-6, the rotation speed R of the clutch input member 12 in is a given threshold R j is smaller than (R in <R j ), the rotation speeds of the drive motor 4 and the clutch input member 12 are further increased, and then the process returns to S1-6.

[0077] In S1-6, the rotation speed R of the clutch input member 12in is a given threshold R j That's all (R in ≧R j ), the process proceeds to S1-7, the braking force F by the braking device 7 is released, and the operation of the first function is terminated.

[0078] Thereafter, the electric vehicle 1 accelerates by increasing the rotation speed of the drive motor 4 according to the target speed, and when the running speed of the electric vehicle 1 reaches the target speed, the rotation speed of the drive motor 4 is kept constant and the electric vehicle continues running.

[0079] The steps (S1-1 to S1-8) shown in FIG. 7 can be interchanged in order or performed simultaneously, as long as no contradiction occurs.

[0080] In the electric vehicle 1 of this example, the rotational torque (reverse input torque) T 13 When the direction of the reverse input torque T coincides with the direction of the rotational torque input to the clutch input member 12 by starting the drive motor 4 to start the electric vehicle 1 running, the brake device 7 generates a reverse input torque T 17 The magnitude of the torque is set to the lower limit T of the first range, which is the torque range in which the phenomenon can occur. min The drive motor 4 is driven to rotate and increase the rotation speed of the clutch input member 12 in a state where braking force F is exerted so that the braking force F is less than or equal to the rotation speed of the clutch input member 12. This makes it possible to reliably prevent the above-mentioned phenomenon from occurring in the reverse input cutoff clutch 6 when the electric vehicle 1 starts to travel downhill from a state where it is parked on a slope. This makes it possible to prevent the behavior of the electric vehicle 1 from becoming unstable and the reverse input cutoff clutch 6 from becoming more susceptible to wear.

[0081] (Second function) Additionally or alternatively, the electric vehicle 1 can have a second function for preventing the occurrence of the above phenomenon during execution of deceleration control of the electric vehicle 1. The second function is to prevent the occurrence of the above phenomenon during execution of deceleration control for decelerating the electric vehicle 1 in order to stop the electric vehicle 1, by preventing a rotational torque (reverse input torque) T 13 The second function is executed when the direction of rotation of the clutch input member 12 matches the direction of rotation of the clutch input member 12. The second function can be executed in either an electric vehicle 1 in which the drive motor 4 is controlled by speed control or position control, or an electric vehicle 1 in which the drive motor 4 is controlled by torque control.

[0082] When the drive motor 4 is controlled by speed control or position control, increasing the braking force of the brake device 7 causes the rotational speed (rotational velocity) of the drive motor 4 to suddenly decrease, and if the rotational speed becomes smaller than the target rotational speed or if the deviation of the rotational angle of the output shaft of the drive motor 4 from the target position increases, the output torque of the drive motor 4 also increases as the rotational speed of the drive motor 4 increases in order to correct the deviation of the rotational speed or rotational angle. This prevents the electric vehicle 1 from suddenly decelerating unintentionally. Thereafter, the rotational speed of the drive motor 4 is reduced according to the target rotational speed or the rotational angle of the output shaft of the drive motor 4 is controlled according to the target position, thereby decelerating and stopping the electric vehicle 1.

[0083] When the drive motor 4 is controlled by torque control, if the braking force by the brake device 7 is increased, the number of rotations (rotational speed) of the drive motor 4 will decrease rapidly if left as is. Therefore, when the drive motor 4 is controlled by torque control, the braking force by the brake device 7 is increased, and at the same time, the magnitude of the rotational torque input to the clutch input member 12 by the drive motor 4 is adjusted to the reverse input torque T 13This prevents the electric vehicle 1 from suddenly decelerating unintentionally. Thereafter, the output torque of the drive motor 4 is reduced in accordance with the target torque, thereby decelerating the electric vehicle 1 and bringing it to a stop.

[0084] The rotational torque (reverse input torque) T that is reversely input to the clutch output member 13 during execution of deceleration control to decelerate the electric vehicle 1. 13 can be obtained by measuring and determining parameters such as the running speed and acceleration of the electric vehicle 1, the inertia torque and running resistance acting on the drive wheels 5, or the rotational torque of the clutch output member 13 using sensors or the like for obtaining these parameters.

[0085] The predetermined second threshold value is a rotation speed of the clutch input member 12 that is sufficient to prevent the occurrence of the above phenomenon in the reverse input disconnection clutch 6. In other words, when the rotation speed of the clutch input member 12 is equal to or greater than the second threshold value, the rotation speed of the clutch output member 13 and the rotational torque (reverse input torque) T 13 The second threshold is determined in advance by experiment, calculation, simulation, etc. The second threshold can be the same as the first threshold, or can be different from the first threshold.

[0086] The second predetermined range is a range of the magnitude of the reverse input torque of the clutch output member 13 in which the above phenomenon can occur in the reverse input cutoff clutch 6. In other words, the rotational torque (reverse input torque) T 13 If the magnitude of is outside the second range, the above phenomenon does not occur regardless of the rotation speed or rotational torque of clutch input member 12 or the rotation speed of clutch output member 13. The second range varies depending on the structure of reverse input disconnection clutch 6, and the dimensions and shapes of the elements that make up reverse input disconnection clutch 6, including clutch input member 12 and clutch output member 13. The second range is determined in advance by experiment, calculation, simulation, etc.

[0087] The second range can be determined experimentally, for example, as follows: A first electric motor is connected to the clutch input member 12, and a second electric motor is connected to the clutch output member 13. The first electric motor rotates the clutch input member 12 in a predetermined direction at a rotation speed that exceeds a predetermined second threshold, and the second electric motor applies a rotational torque of a predetermined magnitude in a predetermined direction to the clutch output member 13. From this state, the first electric motor decelerates the clutch input member 12 at a predetermined rotational deceleration rate, and the reverse input disconnect clutch 6 is visually observed to determine whether the above-mentioned phenomenon occurs.

[0088] Such an experiment is carried out multiple times while changing the rotational deceleration of the clutch input member 12 and the rotational torque applied to the clutch output member 13. By carrying out such an experiment, it is possible to determine the reverse input torque T 13 The second range of magnitude (T min ≦T 13 ≦T max ), i.e., the lower limit T min and upper limit T max Ask for.

[0089] FIG. 10 shows the rotational torque [Nm] applied to the clutch output member 13 on the horizontal axis, and the rotational deceleration [rps 2 An example of a region where the above phenomenon occurs is shown on a graph with the vertical axis representing [value].

[0090] The second range can be the same as the first range or can be different from the first range.

[0091] In this example, the control device 3 has both the first function and the second function, and controls the drive motor 4 by speed control or position control. In this example, the first threshold value and the second threshold value are the same threshold value R j and the first range and the second range are the same range (T min ≦T 13 ≦T max )

[0092] Hereinafter, one example of the operation of the second function that is executed during execution of deceleration control for stopping the electric vehicle 1 will be described in more detail with reference to FIG. 8, although the example is not limited to this.

[0093] First, in S2-1, the rotation speed R of the clutch input member 12 is in is a given threshold R j is less than (R in <R j ) or not.

[0094] In S2-1, the rotation speed R of the clutch input member 12 in is a given threshold R j That's all (R in ≧R j ), the rotation speeds of the drive motor 4 and the clutch input member 12 are further reduced, and then the process returns to S2-1.

[0095] In S2-1, the rotation speed R of the clutch input member 12 in is a given threshold R j is less than (R in <R j ), the process proceeds to S2-2, and the reverse input torque T 13 Get the direction and magnitude of the

[0096] Reverse input torque T 13 There is no particular limitation on the method for obtaining the direction and magnitude of the reverse input torque T 13 The direction and magnitude of the reverse input torque T are calculated by calculating the inertia torque and running resistance acting on the drive wheels 5 based on the running speed and acceleration of the electric vehicle 1 and output signals from a gyro sensor, weight sensor, etc., mounted on the vehicle body 9. 13 can be obtained.

[0097] To calculate the running resistance, the rolling resistance coefficient between the tread of the drive wheel 5 and the road surface is required. The rolling resistance coefficient can be estimated, for example, by estimating the running resistance based on the magnitude of the torque exerted by the drive motor 4 while the electric vehicle 1 is running steadily, and then subtracting the gradient resistance and the like from the running resistance to calculate the rolling resistance. Alternatively, in the case of an automated guided vehicle that transports goods in a factory or the like, the conditions of the road surface on which the vehicle runs are almost constant. In such cases, a predetermined value can be used as the rolling resistance coefficient.

[0098] Alternatively, if the drive unit 2 is provided with a torque sensor that measures the rotational torque of the clutch output member 13 or a member disposed between the clutch output member 13 and the drive wheels 5, the reverse input torque T 13 The direction and magnitude of the

[0099] Next, in S2-3, the reverse input torque T 13 is the same as the rotation direction of the clutch input member 12. During deceleration of the electric vehicle 1, an inertial torque acts on the drive wheels 5, so that the reverse input torque T 13 The direction of rotation is the same as the direction of rotation of the clutch input member 12.

[0100] In S2-3, the reverse input torque T 13 If it is determined that the direction of rotation of the drive motor 4 and the direction in which the clutch input member 12 should be rotationally driven are different directions, there is no possibility that the above phenomenon will occur in the reverse input cutoff clutch 6, so the process proceeds to S2-6, the rotation speed of the drive motor 4 is reduced, the electric vehicle 1 is stopped, and the operation of the second function is terminated.

[0101] In S2-3, the reverse input torque T 13 If it is determined that the direction of rotation of the clutch input member 12 is the same as the direction in which the clutch input member 12 should be rotated, the process proceeds to S2-4, and the reverse input torque T 13 The size of is within a predetermined range (T min ≦T 13≦T max ) is determined.

[0102] In S2-4, the reverse input torque T 13 The magnitude of the reverse input torque T is outside the specified range. 13 The magnitude of is the lower limit T min smaller than (T 13 <T min ), or greater than the upper limit (T 13 >T max ), there is no possibility that the above phenomenon will occur in the reverse input cutoff clutch 6, so the process proceeds to S2-6, the rotation speed of the drive motor 4 is reduced, the electric vehicle 1 is stopped, and the operation of the second function is terminated.

[0103] In S2-4, the reverse input torque T 13 The magnitude of is within a predetermined range (T min ≦T 13 ≦T max ) is determined, proceed to S2-5.

[0104] In S2-5, the braking force F exerted by the braking device 7 is calculated as the reverse input torque T 13 The size of the second range is the lower limit T min In this example, the braking force F is increased by an amount (ΔF) that can be less than the reverse input torque T 13 This makes it possible to make the magnitude of the reverse input torque T 13 Set to 0.

[0105] In this example, the drive motor 4 is controlled by speed control or position control. Therefore, in S2-5, when the braking force F is increased, the drive motor 4 increases its rotational speed and output torque so that the rotational speed (rotational velocity) of the drive motor 4 does not become smaller than the target rotational speed or the deviation of the rotational angle of the output shaft of the drive motor 4 from the target position does not increase. Specifically, when the rotational torque input to the clutch input member 12 is increased by the reverse input torque T 13The output torque of the drive motor 4 increases by the amount that the magnitude of the torque decreases, thereby preventing the electric vehicle 1 from suddenly decelerating unintentionally.

[0106] Next, the process proceeds to S2-6, where the rotation speed of the drive motor 4 is reduced to 0, thereby bringing the electric vehicle 1 to a halt and ending the operation of the second function.

[0107] After the electric vehicle 1 has come to a stop, the reverse input cutoff clutch 6 functions as a parking brake and the drive wheels 5 are locked, so that the braking force F applied by the braking device 7 can be released.

[0108] In the electric vehicle 1 of this example, while deceleration control is being performed to stop the vehicle, the rotational torque (reverse input torque) T 13 The direction of rotation of the clutch input member 12 coincides with the direction of rotation of the clutch input member 12, and the rotation speed of the clutch input member 12 is greater than or equal to a predetermined threshold value R j If the reverse input torque T 13 The magnitude of the torque is set to the lower limit T of the second range, which is the torque range in which the above phenomenon can occur. min The braking force F by the brake device 7 is increased so that the braking force F can be less than 1 / 2 s. Therefore, during execution of deceleration control to decelerate the electric vehicle 1 in order to stop the electric vehicle 1, it is possible to reliably prevent the occurrence of a phenomenon in which the clutch input member 12 and the clutch output member 13 intermittently rotate while the reverse input cutoff clutch 6 alternates in a short period between an unlocked state in which torque can be transmitted between the clutch input member 12 and the clutch output member 13 and a locked state in which torque cannot be transmitted. This makes it possible to prevent the behavior of the electric vehicle 1 from becoming unstable and the reverse input cutoff clutch 6 from becoming more susceptible to wear.

[0109] <Structure of the reverse input cut-off clutch> The following describes in more detail an example of the reverse input cutoff clutch 6 that can be suitably applied to the drive device 2 of this embodiment. The reverse input cutoff clutch 6 includes a clutch input member 12, a clutch output member 13, a pressed member 11, and an engaging element 14.

[0110] In the description of the reverse input cutoff clutch 6 of this example, the axial, radial, and circumferential directions of the reverse input cutoff clutch 6 coincide with the axial, radial, and circumferential directions of the clutch input member 12, coincide with the axial, radial, and circumferential directions of the pressed surface 15, and coincide with the axial, radial, and circumferential directions of the clutch output member 13. Furthermore, one axial side refers to the clutch input member 12 side (the right side in FIG. 3), and the other axial side refers to the clutch output member 13 side (the left side in FIG. 3).

[0111] The pressed member 11 is supported and fixed to a fixed portion that does not rotate even when the electric vehicle 1 is running, or is provided integrally with the fixed portion, and its rotation is restricted.

[0112] The pressed member 11 has a pressed surface 15 on its inner circumferential surface. The pressed surface 15 constitutes a surface that comes into contact with the pressing surface 26 of the engaging element 14 when the engaging element 14 moves radially outward, that is, in a direction approaching the pressed surface 15. The shape of the pressed member 11 is not limited as long as it is configured to have the pressed surface 15 on its inner circumferential surface. The pressed surface 15 has an annular shape when viewed in the axial direction, and in this example, has a cylindrical shape whose inner diameter does not change in the axial direction, although this is not limited to this.

[0113] The input side engaging portion 16 of the clutch input member 12 and the output side engaging portion 22 of the clutch output member 13 are arranged radially inside the pressed surface 15. The input side engaging portion 16, the output side engaging portion 22, and the engaging element 14 are able to rotate around the central axis of the pressed surface 15 radially inside the pressed surface 15.

[0114] The clutch input member 12 is disposed coaxially with the pressed surface 15, and is connected to the drive motor 4 side, for example, to the output shaft of the drive motor 4, or, if the reducer 10 is disposed between the drive motor 4 and the reverse input cutoff clutch 6, to the output shaft of the reducer 10. In other words, the clutch input member 12 is rotatably supported by the fixed portion, and is rotationally driven by the drive motor 4. In this example, the clutch input member 12 is connected to the output shaft of the drive motor 4.

[0115] The clutch input member 12 has an input-side engaging portion 16 arranged radially inward of the pressed surface 15. The input-side engaging portion 16 is provided in a portion radially outwardly displaced from the rotation center O of the clutch input member 12, and has a portion that engages with the input-side engaged portion 27 of the engager 14. The input-side engaging portion 16 is configured so that its radially inner surface 19 engages (contacts) with the radially inner surface 29 of the input-side engaged portion 27 as the clutch input member 12 or the engager 14 rotates. That is, in this example, the radially inner surface 19 of the input-side engaging portion 16 forms the portion that engages with the input-side engaged portion 27.

[0116] The structure of the clutch input member 12 is arbitrary as long as it has an input-side engaging portion 16 that can engage with the input-side engaged portion 27 of the engager 14, is connected to the drive motor 4, and can input rotational torque from the drive motor 4. In this example, the clutch input member 12 has a base portion 17 and an input shaft portion 18 in addition to the input-side engaging portion 16.

[0117] The substrate portion 17 has a substantially circular end face shape when viewed in the axial direction.

[0118] The input shaft portion 18 protrudes axially from the center of one axial side surface of the base portion 17. The input shaft portion 18 is connected to the output shaft of the drive motor 4 so as to be able to transmit torque, or is integral with the output shaft of the drive motor 4.

[0119] The input side engaging portion 16 protrudes from a portion of the side surface of the base plate portion 17 on the other axial side, the portion being radially outwardly spaced from the rotation center O, toward the other axial side.

[0120] The shape of the input side engaging portion 16 is not limited as long as it is configured to engage with the input side engaged portion 27 of the engaging element 14. Furthermore, the number of input side engaging portions 16 is determined according to the number of engaging elements 14, and when the engaging element 14 is configured with a plurality of engaging elements 14, the input side engaging portion 16 is also configured with a plurality of input side engaging portions 16.

[0121] In the reverse input cutoff clutch 6 of this example, the engaging elements 14 are configured with two engaging elements 14. Therefore, the input side engaging portion 16 is configured with two input side engaging portions 16 to match the number of engaging elements 14. The two input side engaging portions 16 are arranged at two radially opposite positions on the other axial side surface of the base plate portion 17, and are spaced apart from each other in the radial direction of the clutch input member 12. Furthermore, each input side engaging portion 16 has a shape that is symmetrical in the circumferential direction.

[0122] In this example, each input-side engaging portion 16 has an end face shape that is generally fan-shaped or trapezoidal, with its circumferential width increasing radially outward when viewed from the axial direction. The radially inner surfaces 19 of the two input-side engaging portions 16 are formed by flat surfaces that are parallel to each other, and the radially outer surface 20 of each input-side engaging portion 16 has the same cylindrical contour shape as the outer circumferential surface of the base portion 17. The two circumferential side surfaces 21 of each input-side engaging portion 16 are formed by flat surfaces that slope away from each other radially outward.

[0123] The clutch output member 13 has an output-side engaging portion 22 that is located radially inward of the input-side engaging portion 16 on the radially inner side of the pressed surface 15, and is arranged coaxially with the pressed surface 15. That is, the clutch output member 13 is also arranged coaxially with the clutch input member 12. The clutch output member 13 is rotatably supported by the pressed member 11 or the fixed portion, and is connected to the drive wheels 5 side, for example, the drive shaft of the drive wheels 5, or, if a reducer 10 is arranged between the reverse input cutoff clutch 6 and the drive wheels 5, is connected to the input shaft of the reducer 10. That is, the clutch output member 13 is configured to output rotational torque to the drive wheels 5 side as it rotates. In this example, the clutch output member 13 is connected to the input shaft of the reducer 10.

[0124] The output side engaging portion 22 is located radially inward of the input side engaging portion 16, and forms a portion that engages with the output side engaged portion 28 as the clutch output member 13 or the engaging element 14 rotates, i.e., is positioned so that a portion of it can engage with the output side engaged portion 28 of the engaging element 14.

[0125] The structure of the clutch output member 13 is arbitrary as long as it has an output side engaging portion 22 that can engage with the output side engaged portion 28 of the engager 14, is connected to the drive wheels 5, and is capable of outputting rotational torque to the drive wheels 5. In this example, the clutch output member 13 has an output shaft portion 23 in addition to the output side engaging portion 22.

[0126] The output shaft portion 23 is provided in a portion adjacent to the other axial side of the output side engagement portion 22, and is connected to the drive wheel 5 side (input shaft of the reducer 10) so as to be able to transmit torque, or is formed integrally with the input shaft of the reducer 10.

[0127] The output side engaging portion 22 protrudes from the center of a side surface on one axial side of the output shaft portion 23 toward one axial side.

[0128] The shape of the output side engaging portion 22 is not limited as long as it is configured to have a portion that engages with the output side engaged portion 28. Furthermore, the number of portions of the output side engaging portion 22 that engage with the output side engaged portion 28 is determined according to the number of engaging elements 14, and when the engaging element 14 is configured with a plurality of engaging elements 14, the output side engaging portion 22 is also configured to have a plurality of the engaging portions. Note that even when the engaging element is configured with a single engaging element, the output side engaging portion can have a plurality of the engaging portions.

[0129] In this example, the output side engaging portion 22 is configured to have portions that engage with two output side engaged portions 28, in accordance with the number of the engaging pieces 14.

[0130] In this example, the output side engaging portion 22 has a substantially rectangular or oval end face shape when viewed in the axial direction, and protrudes toward one axial side from the center of one axial end face of the output shaft portion 23. In other words, the distance from the rotation center O of the clutch output member 13 to the outer circumferential surface of the output side engaging portion 22, which is the portion that engages with the output side engaged portion 28, is not constant in the circumferential direction. Therefore, the output side engaging portion 22 has a cam function.

[0131] More specifically, the outer peripheral surface of the output side engaging portion 22 is made up of two parallel flat surfaces 24 and two partially cylindrical convex surfaces 25. Therefore, the distance from the rotation center O of the clutch output member 13 to the outer peripheral surface of the output side engaging portion 22 is not constant in the circumferential direction. Each of the two convex surfaces 25 is made up of a partially cylindrical surface with the rotation center O of the clutch output member 13 as its center.

[0132] The output side engaging portion 22 is plane-symmetrical with respect to an imaginary plane that passes through the rotation center O of the clutch output member 13 and is perpendicular to the flat surface 24. Furthermore, the output side engaging portion 22 is plane-symmetrical with respect to an imaginary plane that passes through the rotation center O of the clutch output member 13 and is parallel to the flat surface 24.

[0133] In this example, the output side engaging portion 22 is disposed between the output side engaged portions 28 of the two engaging elements 14 in the portion between the two input side engaging portions 16.

[0134] The engaging element 14 has a pressing surface 26 facing the pressed surface 15, an input side engaged portion 27 engageable with the input side engaging portion 16, and an output side engaged portion 28 engageable with the output side engaging portion 22, and is arranged so as to be able to move in a first direction, which is the direction towards or away from the pressed surface 15 of the pressing surface 26.

[0135] The engaging element 14 may be configured by one engaging element 14 or by two or more engaging elements 14.

[0136] In this example, the engaging element 14 is made up of two engaging elements 14. Each engaging element 14 has the function of an engaging element 14. The configuration of each engaging element 14 will be described below.

[0137] The radial direction with respect to the engaging element 14 is the direction of approach or distance between the pressing surface 26 and the pressed surface 15, and corresponds to the direction indicated by arrow A in Fig. 4. The width direction with respect to the engaging element 14 is the direction perpendicular to both the direction of approach or distance between the pressing surface 26 and the pressed surface 15 and the axial direction of the clutch input member 12, and corresponds to the direction indicated by arrow B in Fig. 4. In this example, the radial direction with respect to the engaging element 14 is referred to as the first direction, and the width direction with respect to the engaging element 14 is referred to as the second direction.

[0138] The engaging element 14 has a substantially semicircular end face shape when viewed from the axial direction, and has a shape that is symmetrical with respect to the width direction.

[0139] The pressing surface 26 is provided on the radially outer surface of the engaging element 14 facing the pressed surface 15. The pressing surface 26 is configured as a partially cylindrical convex curved surface having a radius of curvature equal to or smaller than the radius of curvature of the pressed surface 15, preferably smaller than the radius of curvature of the pressed surface 15. The pressing surface 26 can be provided at one location (including the entirety) or at two or more locations on the radially outer surface of the engaging element 14. In this example, the pressing surface 26 is configured as two pressing surfaces 26 provided at two locations on the radially outer surface of the engaging element 14 that are spaced apart from each other in the circumferential direction. Each pressing surface 26 is configured as a partially cylindrical convex curved surface having a radius of curvature smaller than the radius of curvature of the pressed surface 15.

[0140] When viewed from the axial direction, the portion of the radially outer surface of the engaging element 14 that is circumferentially deviated from the two pressing surfaces 26 is located radially inward of an imaginary circle that is centered on the central axis of the clutch input member 12 and is tangent to the two pressing surfaces 26. In other words, when the two pressing surfaces 26 are in contact with the pressed surface 15, the portion that is circumferentially deviated from the two pressing surfaces 26 does not come into contact with the pressed surface 15.

[0141] The pressing surface 26 preferably has a surface property that has a higher coefficient of friction with the pressed surface 15 than the other parts of the engaging part 14. The pressing surface 26 can be formed integrally with the other parts of the engaging part 14, or can be formed by the surface of a friction material fixed to the other parts of the engaging part 14 by sticking, bonding, or the like.

[0142] The input side engaged portion 27 has any structure that can engage with the input side engaging portion 16 as the clutch input member 12 or the engaging element 14 rotates, and is disposed at any position that can engage with the input side engaging portion 16. In this example, the input side engaged portion 27 is provided at a radially intermediate portion of the widthwise center of the engaging element 14. More specifically, although not limited thereto, the input side engaged portion 27 has a substantially arch-shaped outline when viewed in the axial direction, and is configured by a through-hole that axially passes through a radially intermediate portion of the widthwise center of the engaging element 14.

[0143] The input side engaged portion 27 has a size that allows the input side engaging portion 16 to be loosely inserted therein. Therefore, with the input side engaging portion 16 inserted inside the input side engaged portion 27, there is a gap between the input side engaging portion 16 and the inner surface of the input side engaged portion 27 in both the width direction and the radial direction of the engaging element 14. Therefore, the input side engaging portion 16 can be displaced relative to the input side engaged portion 27 in the rotational direction of the clutch input member 12, and the input side engaged portion 27 can be displaced relative to the input side engaging portion 16 in the radial direction of the engaging element 14.

[0144] In this example, of the inner surfaces of the input side engaged portion 27, the radially inner surface 29 facing radially outward is composed of a flat surface perpendicular to the first direction, and the radially outer surface 30 of the inner surfaces of the input side engaged portion 27 facing radially inward is composed of a curved surface having an approximately arc-shaped contour when viewed from the axial direction.

[0145] The output side engaged portion 28 has any structure that can engage with the output side engaging portion 22 as the clutch output member 13 or the engaging element 14 rotates, and is disposed at any position that can engage with the output side engaging portion 22. In this example, the output side engaged portion 28 is provided on the radially inner surface of the engaging element 14, in the center in the width direction.

[0146] In this example, the engaging element 14 has, on its radially inner surface, a flat surface portion 31 that is perpendicular to the radial direction of the engaging element 14, and the flat surface portion 31 has two protrusions 32 that protrude radially inward at two positions in the width direction of the engaging element 14. The output-side engaged portion 28 is formed by a portion of the flat surface portion 31 that is located between the two protrusions 32 in the width direction. In this example, the width dimension of the output-side engaged portion 28, i.e., the distance between the two protrusions 32, is larger than the width dimension of the flat surface 24 of the output-side engaging portion 22.

[0147] In the reverse input cutoff clutch 6 of this example, the pressing surfaces 26 of the two engaging elements 14 are oriented radially opposite to each other, and the flat surface portions 31 are opposed to each other. Each engaging element 14 is disposed radially inside the pressed member 11 so as to be movable in a first direction, which is the radial direction of each engaging element 14 and corresponds to the direction in which the pressing surfaces 26 move toward and away from the pressed surface 15. Furthermore, the two input-side engaging portions 16 of the clutch input member 12 disposed on one axial side are axially inserted into the input-side engaged portions 27 of the two engaging elements 14, and the output-side engaging portion 22 of the clutch output member 13 disposed on the other axial side is axially inserted between the output-side engaged portions 28 of the two engaging elements 14. In other words, the two engaging elements 14 are disposed so that the output-side engaging portions 22 are sandwiched from the radially outer side by the output-side engaged portions 28.

[0148] The inner diameter dimension of the pressed member 11 and the radial dimension of the engaging elements 14 are regulated so that when the two engaging elements 14 are positioned radially inside the pressed member 11, there is a gap in at least one of the areas between the pressed surface 15 and the two pressing surfaces 26, and between the tip surfaces of the two combinations of protrusions 32 formed by the two protrusions 32 of the two engaging elements 14 facing each other.

[0149] The reverse input cutoff clutch 6 of this example further includes, as an optional component, a biasing member 33 that elastically biases the engaging elements 14 radially outward, which is a direction in which the engaging elements 14 approach the pressed surface 15. The biasing member 33 can be made of a spring such as a leaf spring, a coil spring, or a disc spring, or an elastic material such as rubber, elastomer, or synthetic resin. The number of biasing members 33 is not particularly limited and is determined appropriately depending on the number of engaging elements 14.

[0150] In this example, the biasing member 33 is composed of two biasing members 33 arranged at two positions in the width direction between the radially inner surfaces of the two engaging pieces 14, and each biasing member 33 is composed of a compression coil spring. A protrusion 32 is inserted into the inside of each biasing member 33 at both ends in the extension direction. This prevents each biasing member 33 from falling off from between the two engaging pieces 14.

[0151] The two biasing members 33 elastically bias the two engaging elements 14 in a direction that brings them closer to the pressed surface 15 by the force of elastic restoration. As a result, when no torque is applied to either the clutch input member 12 or the clutch output member 13, the pressing surfaces 26 of the two engaging elements 14 are in contact with the pressed surface 15.

[0152] The biasing member 33 can also be disposed between the clutch output member 13 and the engaging element 14. For example, if the biasing member 33 is formed of a leaf spring, the biasing member 33 can be sandwiched between the output side engaging portion 22 and the output side engaged portion 28.

[0153] By keeping the pressing surface 26 in contact with the pressed surface 15 when no torque is applied to either the clutch input member 12 or the clutch output member 13, when rotational torque is reversely input to the clutch output member 13, it is possible to quickly increase the surface pressure at the contact point between the pressing surface 26 and the pressed surface 15 without having to reduce the gap between them. In other words, the reverse input cutoff clutch 6 can be quickly switched to the locked mode.

[0154] <Reverse input cutoff clutch operation> When rotational torque is input from the drive motor 4 to the clutch input member 12, the input side engaging portion 16 engages with the input side engaged portion 27, causing the engager 14 to move in a direction away from the pressed surface 15 and causing the output side engaged portion 28 to engage with the output side engaging portion 22. This causes the reverse input cutoff clutch 6 to switch to an unlock mode in which the rotational torque input to the clutch input member 12 is transmitted to the clutch output member 13.

[0155] Specifically, when rotational torque is input from the drive motor 4 to the clutch input member 12, the engaging element 14 moves in a direction away from the pressed surface 15, regardless of the rotational direction of the clutch input member 12. More specifically, as shown in Figure 5, the input side engaging portion 16 rotates inside the input side engaged portion 27 in the rotational direction of the clutch input member 12 (counterclockwise in the example of Figure 5).

[0156] This reduces the gap between the radial inner surface 19 of the input side engaging portion 16 and the radial inner surface 29 of the input side engaged portion 27, and brings the radial inner surface 19 of the input side engaging portion 16, or the connection portion between the radial inner surface 19 and the circumferential side surface 21, into contact with the radial inner surface 29 of the input side engaged portion 27.

[0157] When the clutch input member 12 rotates further from this state, the radially inner surface 19 of the input-side engaging portion 16 or the connecting portion presses the radially inner surface 29 of the input-side engaged portion 27 radially inward, causing the engager 14 to move in a direction away from the pressed surface 15. That is, the engager 14 moves radially inward based on engagement with the clutch input member 12, and the output-side engaged portion 28 of the engager 14 engages with the output-side engaging portion 22 of the clutch output member 13. In this example, the two engagers 14 move radially inward, that is, in directions approaching each other, based on engagement with the clutch input member 12, so that the radially inner surfaces of the two engagers 14 approach each other, and the output-side engaged portions 28 of the two engagers 14 clamp the output-side engaging portion 22 of the clutch output member 13 from both radial sides.

[0158] In this example, the clutch output member 13 is rotated so that the flat surface 24 of the output side engaging portion 22 is parallel to the flat surface portion 31 of the engager 14, and the output side engaging portion 22 and the output side engaged portion 28 of the engager 14 are engaged without rattle. Due to the engagement between the output side engaging portion 22 and the output side engaged portion 28, the rotational torque input to the clutch input member 12 is transmitted to the clutch output member 13 via the engager 14.

[0159] In contrast, when a rotational torque is reversely input to the clutch output member 13 from the drive wheel 5 side, the engaging element 14 moves in a direction approaching the pressed surface 15, causing the pressing surface 26 to frictionally engage with the pressed surface 15. As a result, the reverse input cutoff clutch 6 switches to a lock mode in which the rotation of the clutch output member 13 is prevented.

[0160] Specifically, when a rotational torque is input in reverse from the input shaft of the reducer 10 to the clutch output member 13, the engaging element 14 moves in a direction approaching the pressed surface 15, regardless of the rotational direction of the clutch output member 13. More specifically, as shown in Fig. 6 , the output-side engaging portion 22 rotates radially inside the output-side engaged portion 28 of the engaging element 14 in the rotational direction of the clutch output member 13 (clockwise in the example of Fig. 6 ). A part of the output-side engaging portion 22, in this example, the connection portion (corner portion) between the flat surface 24 and the convex curved surface 25 of the outer circumferential surface of the output-side engaging portion 22, presses the output-side engaged portion 28 radially outward, and the engaging element 14 moves in a direction approaching the pressed surface 15.

[0161] That is, based on the engagement with the clutch output member 13, the engaging element 14 moves radially outward, i.e., in a direction away from each other, and the pressing surface 26 of the engaging element 14 comes into contact with the pressed surface 15 and frictionally engages with the pressed surface 15. As a result, the engaging element 14 is stretched (sandwiched) between the output side engaging portion 22 and the pressed member 11, and the rotational torque reversely input to the clutch output member 13 is completely blocked and is no longer transmitted to the clutch input member 12.

[0162] In order to enable the above operation, the size of the gap between each component of the reverse input cutoff clutch 6 is adjusted. In particular, when the pressing surface 26 of the engaging element 14 is in contact with the pressed surface 15, a gap is set to exist between the radially inner surface 19 of the input side engaging portion 16 and the radially inner surface 29 of the input side engaged portion 27.

[0163] Furthermore, in this example, the dimensions and shapes of the pressed member 11, the clutch input member 12, the clutch output member 13, and the two engaging elements 14 are regulated so as to satisfy the following relationships.

[0164] As the clutch output member 13 rotates in a predetermined direction (for example, the clockwise direction in FIG. 4), the two pressing surfaces 26 are pressed against the pressed surfaces 15, and as the clutch input member 12 rotates in a direction opposite to the predetermined direction (for example, the counterclockwise direction in FIG. 4), the input side engaging portion 16 and the input side engaged portion 27 are engaged (a part of the input side engaging portion 16 is in contact with the input side engaged portion 27). In this state, the contact portion P in and the rotation center O of the clutch input member 12 in the second direction, the first distance D1 is the distance between the contact point P out is set to be smaller than the second distance D2 in the second direction between the rotation center O of the clutch output member 13 and the clutch output member 13 (D1 <D2)。

[0165] Also, as shown in Figure 6, when a rotational torque is input in reverse to the clutch output member 13 and the two pressing surfaces 26 of the engaging element 14 are in contact with the pressed surface 15 in a locked state, the contact portion C1 between the output side engaging portion 22 and the output side engaged portion 28 is located closer to the center of rotation O of the clutch output member 13 in the first direction (lower side in Figure 6) than the virtual straight line L connecting the center of rotation O of the clutch output member 13 and the abutment portion C2 between the pressing surface 26 of one of the two pressing surfaces 26 (the side closer to the contact portion C1 than the center of rotation O of the clutch output member 13 in the second direction) and the pressed surface 15.

[0166] However, when implementing the present disclosure, the magnitude relationship between the first distance D1 and the second distance D2 and the positional relationship of the contact portion C1 with respect to the imaginary line L are not limited to those in this example and can be set arbitrarily. For example, the first distance D1 can be set greater than the second distance D2, and the contact portion C1 can be configured to be located closer to the rotation center of the output member than the imaginary line L. Alternatively, the contact portion C1 can be configured to be located farther from the rotation center of the output member than the imaginary line L.

[0167] In addition, when the reverse input cutoff clutch 6 comprises a clutch input member 12, a clutch output member 13, a pressed member 11, and an engaging element 14, the predetermined first range in the first function and the predetermined second range in the second function vary depending on the dimensions and shapes of each part of the pressed member 11, the clutch input member 12, the clutch output member 13, and the two engaging elements 14.Furthermore, when the reverse input cutoff clutch comprises a biasing member 33, the first range and the second range also vary depending on the elasticity of the biasing member 33, etc.

[0168] [Example 2] A second example of the embodiment of the present disclosure will be described with reference to Fig. 11. This example differs from the first example in that the drive motor 4 is controlled by torque control.

[0169] In this example, during execution of deceleration control to stop the electric vehicle 1, the reverse input cutoff clutch 6 alternates between an unlocked state in which torque can be transmitted between the clutch input member 12 and the clutch output member 13 and a locked state in which torque cannot be transmitted, and while the second function is being executed to prevent the occurrence of a phenomenon in which the clutch input member 12 and the clutch output member 13 rotate intermittently, in S2-5, the braking force F by the brake device 7 is controlled by the reverse input torque T 13 The size of the second range is the lower limit T min Preferably, the reverse input torque T 13 After increasing the magnitude of the parameter by the amount (ΔF) that can make the magnitude of the parameter zero, the process proceeds to S2-5'.

[0170] In S2-5', the magnitude of the rotational torque applied to the clutch input member 12 by the drive motor 4 is adjusted based on the increase in the braking force F. 13 In this example, the reverse input torque T 13 This prevents the electric vehicle 1 from suddenly decelerating unintentionally.

[0171] That is, when the drive motor 4 is controlled by torque control with the magnitude of the output torque as a target value, increasing the braking force F by the braking device 7 will result in a sudden decrease in the rotational torque of the drive wheels 5. In this example, by increasing the output torque of the drive motor 4 to compensate for the decrease in the rotational torque of the drive wheels 5 that occurs as the braking force F increases, the decrease in the rotational torque of the drive wheels 5 is suppressed, and a sudden deceleration of the electric vehicle 1 is prevented.

[0172] After increasing the output torque of the drive motor 4 in S2-5', the process proceeds to S2-6, where the rotation speed of the drive motor 4 is reduced, the electric vehicle 1 is stopped, and the operation of the second function is terminated.

[0173] The configuration and effects of other parts of the second example are the same as those of the first example.

[0174] [Example 3] A third example of the embodiment of the present disclosure will be described with reference to FIG.

[0175] In the electric vehicle 1a of this example, the number of drive units 2 is changed from that of the electric vehicle of the first example. The electric vehicle 1a of this example is equipped with two drive units 2. The two drive units 2 are supported at two locations on the left and right sides of the vehicle body 9. Although not limited to this, in this example, each drive unit 2 is configured to rotate and drive one drive wheel 5 using one drive motor 4 via a reverse input cutoff clutch 6 and a reducer 10.

[0176] The electric vehicle 1a of this example includes, as an optional component, a non-driven wheel 34 that is not driven by an electric motor. The non-driven wheel 34 is configured as a single non-driven wheel 34 supported via a fork in the center of the vehicle body 9 in the left-right direction, at a position offset in the front-rear direction from the portion of the vehicle body 9 where the two drive units 2 are supported. The fork is a member for supporting the non-driven wheel 34 and includes a top mount supported on the vehicle body 9 so as to be rotatable about a pivot shaft extending in the up-down direction, and two blades bent downward from both sides of the top mount in the width direction. The non-driven wheel 34 is disposed to extend horizontally and is supported so as to be rotatable about an axis whose ends are supported by the two blades.

[0177] The other configurations and effects of the third example are the same as those of the first example.

[0178] [Example 4] A fourth example of the embodiment of the present disclosure will be described with reference to FIG.

[0179] The electric vehicle 1b of this example is provided with one drive unit 2a, which is provided at one location in the front-rear direction of the vehicle body 9.

[0180] In this example, the drive unit 2a is configured so that one drive motor 4 drives two drive wheels 5a to rotate.

[0181] The two drive wheels 5a extend in the left-right direction and are connected to both axial ends of a drive shaft 35 that is rotatably supported on the vehicle body 9 so as to be able to transmit torque.

[0182] The drive shaft 35 is configured to be rotatable by the drive motor 4 via the reverse input cutoff clutch 6 and the reducer 10. That is, the drive device 2a includes the reverse input cutoff clutch 6 and the reducer 10 in the torque transmission path from the drive motor 4 to the drive shaft 35.

[0183] The drive unit 2a also includes two brake units 7 for braking the two drive wheels 5a, respectively.

[0184] The configuration and effects of other parts of the fourth example are the same as those of the first example.

[0185] The first to fourth examples of the embodiment of the present disclosure can be combined as appropriate as long as no contradiction occurs. [Explanation of symbols]

[0186] 1, 1a, 1b electric vehicles 2, 2a Drive unit 3. Control device 4 Drive motor 5, 5a Drive wheels 6 Reverse input cutoff clutch 7 Braking device 9. Body 10 Reducer 11 Pressed member 12 Clutch input member 13 Clutch output member 14 Engagement element 15 Pressed surface 16 Input side engagement portion 17 Circuit board section 18 Input shaft 19 Radial inner surface 20 Radial outer surface 21 Circumferential side 22 Output side engagement portion 23 Output shaft 24 Flat surface 25 Convex curved surface 26 Pressing surface 27 Input side engaged portion 28 Output side engaged part 29 Radial inner surface 30 Radial outer surface 31 Flat surface part 32 Convex part 33 biasing member 34 Non-driving wheels 35 drive shaft

Claims

1. A drive system comprising a drive motor, a drive wheel, a clutch input member connected to the drive motor, and a clutch output member connected to the drive wheel, wherein a reverse input blocking clutch transmits torque input from the drive motor to the clutch input member to the clutch output member, but does not transmit torque input in reverse from the drive wheel to the clutch output member to the clutch input member, and a braking device positioned on the drive wheel side of the torque transmission path from the drive motor to the drive wheel, and applying braking force to the drive wheel, A control device that controls the drive motor and the braking device, An electric vehicle equipped with, The control device is When the direction of the reverse input torque, which is the rotational torque reversed from the drive wheel side to the clutch output member, is the same as the direction of rotation of the clutch input member connected to the drive motor side, and the magnitude of the reverse input torque is within a predetermined range, the braking device generates or increases braking force so that the magnitude of the reverse input torque is less than the lower limit of the predetermined range. Electric vehicle.

2. The electric vehicle according to claim 1, wherein the control device, when starting to travel from a parked state in a direction that rotates the clutch input member in the same direction as the reverse input torque, which is a rotational torque reversed input to the clutch output member, generates a braking force so that the magnitude of the reverse input torque is less than the lower limit of the first range when the magnitude of the reverse input torque is within a predetermined first range, rotates the clutch input member with the drive motor, and releases the braking force when the rotational speed of the clutch input member reaches or exceeds a predetermined first threshold.

3. The braking force is such that the magnitude of the reverse input torque can be reduced to zero. The electric vehicle according to claim 2.

4. The electric vehicle according to claim 1, which has a second function that, while deceleration control is being performed, when the rotational speed of the clutch input member is below a predetermined second threshold, the direction of the reverse input torque is the same as the rotational direction of the clutch input member, and the magnitude of the reverse input torque is within a predetermined second range, increases the braking force by an amount that allows the magnitude of the reverse input torque to be below the lower limit of the second range, and then continues the deceleration control.

5. The amount by which the braking force is increased is such that the magnitude of the reverse input torque can be reduced to zero. The electric vehicle according to claim 4.

6. The control device controls the drive motor by speed control or position control while the second function is being performed. The electric vehicle according to claim 4.

7. While the control device is performing the second function, it controls the drive motor by torque control and increases the braking force, and at the same time increases the magnitude of the rotational torque input to the clutch input member by the amount by which the reverse input torque has decreased based on the increase in the braking force. The electric vehicle according to claim 4.

8. The aforementioned reverse input blocking clutch is A member to be pressed having a surface to be pressed on its inner circumferential surface, The clutch input member has an input-side engaging portion located radially inward of the pressed surface and is arranged coaxially with the pressed surface, The clutch output member has an output engagement portion located radially inward from the input engagement portion on the radially inward side of the pressed surface, and is arranged coaxially with the pressed surface, An engaging element having a pressing surface facing the pressed surface, an input-side engaged portion that can engage with the input-side engaging portion, and an output-side engaged portion that can engage with the output-side engaging portion, and arranged to be movable in the radial direction, Equipped with, When rotational torque is input to the clutch input member, the engaging element moves radially inward based on the input-side engaging portion engaging with the input-side engaged portion, and transmits the rotational torque input to the clutch input member to the clutch output member by engaging the output-side engaged portion with the output-side engaging portion. Conversely, when rotational torque is input in reverse to the clutch output member, the engaging element presses the pressing surface against the pressed surface based on the output-side engaging portion engaging with the output-side engaged portion, thereby frictionally engaging the pressing surface with the pressed surface. An electric vehicle according to any one of claims 1 to 7.

9. The aforementioned pressing surface is composed of two pressing surfaces, As the clutch output member rotates, the two pressing surfaces are pressed against the pressed surface, and as the clutch input member rotates in the opposite direction to the rotation direction of the clutch output member, the input side engaging portion and the input side engaged portion are engaged. In this state, the distance between the contact portion of the input side engaging portion and the input side engaged portion and the rotation center of the clutch input member is smaller than the distance between the contact portion of the output side engaging portion and the output side engaged portion and the rotation center of the clutch output member in the second direction, with respect to both the first direction, which is the near-far direction of the pressing surface relative to the pressed surface, and the rotation center of the clutch input member. When rotational torque is input in reverse to the clutch output member, and the two pressing surfaces are in contact with the pressed surface, the contact portion between the output-side engaging portion and the output-side engaged portion is located closer to the rotation center of the clutch output member with respect to the first direction than the imaginary line connecting the contact portion between one of the two pressing surfaces and the pressed surface and the rotation center of the clutch output member. The electric vehicle according to claim 8.

10. The electric vehicle according to claim 9, wherein the reverse input blocking clutch comprises a biasing member that elastically biases the engaging element radially outward.

11. The drive motor and Drive wheels and, A reverse input blocking clutch having a clutch input member connected to the drive motor side and a clutch output member connected to the drive wheel side, which transmits torque input from the drive motor side to the clutch input member to the clutch output member, but does not transmit torque input in reverse from the drive wheel side to the clutch output member to the clutch input member, A braking device is positioned on the drive wheel side of the torque transmission path from the drive motor to the drive wheel, and applies braking force to the drive wheel, A control method for an electric vehicle drive system, comprising: When the direction of the reverse input torque, which is the rotational torque reversed from the drive wheel side to the clutch output member, is the same as the direction of rotation of the clutch input member connected to the drive motor side, and the magnitude of the reverse input torque is within a predetermined range, the braking device generates or increases braking force so that the magnitude of the reverse input torque is less than the lower limit of the predetermined range. A control method for the drive system of an electric vehicle.

12. A control method for an electric vehicle drive device according to claim 11, wherein, when starting to drive from a parked state in a direction that rotates the clutch input member in the same direction as the reverse input torque, which is a rotational torque reversed input to the clutch output member, if the magnitude of the reverse input torque is within a predetermined first range, the braking force is generated so that the magnitude of the reverse input torque can be reduced to less than the lower limit of the first range, and after the clutch input member is rotationally driven by the drive motor, the braking force is released when the rotational speed of the clutch input member reaches or exceeds a predetermined first threshold.

13. A control method for an electric vehicle drive system according to claim 11 or 12, wherein, while deceleration control is being performed, the rotational speed of the clutch input member is less than or equal to a predetermined second threshold, the direction of the reverse input torque, which is the rotational torque reversed and input to the clutch output member, is the same as the rotational direction of the clutch input member, and the magnitude of the reverse input torque is within a predetermined second range, the braking force is increased by an amount that allows the magnitude of the reverse input torque to be less than the lower limit of the second range, and then the deceleration control is continued.

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