Drive control device

Abstract

To perform drive control for a plurality of driving axles by driving force according to axle load distribution.SOLUTION: A drive control device 1 of a multiaxial driving electric motor car 2 with a rear-front axle 4 rotation-driven by a first electric motor 6 and a rear-rear axle 5 rotation-driven by a second electric motor 7 comprises: an air suspension control part 10 which performs an axle load distribution change control which changes axle load distribution of the rear-front axle 4 and the rear-rear axle 5; and a drive control part 11 which performs drive control of the first electric motor 6 and the second electric motor 7. The drive control part 11 performs, when the air suspension control part 10 performs the axle load distribution change control, a driving force change control which changes driving force of the first electric motor 6 and the second electric motor 7.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a drive control device for a multi-axle drive electric vehicle having a plurality of drive axles. [Background technology]

[0002] The air suspension vehicle described in Patent Document 1 has front and rear axles to which power is transmitted via an inter-axle differential. When the wheels of the rear axle slip on a slope or bumpy road, this air suspension vehicle improves starting performance by reducing the axle load on the rear axle and locking the inter-axle differential. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2000-006633 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a multi-axle drive electric vehicle having multiple drive axles, each drive axle is driven independently. In other words, a multi-axle drive electric vehicle is not provided with an inter-axle differential like the air suspension vehicle described in Patent Document 1, and the differential of each drive axle is not locked. For this reason, in a multi-axle drive electric vehicle, the driving force of the multiple drive axles does not change even if the axle load distribution of the multiple drive axles changes.

[0005] For example, when the distribution of axle loads among multiple drive axles is changed, the wheels of the drive axles with increased axle loads will have higher ground pressure with the road surface, but the wheels of the drive axles with reduced axle loads will have lower ground pressure with the road surface and will spin at a higher speed. This results in excessive energy loss and worsens the power consumption (fuel economy). In addition, wheel spinning can increase the amount of water splashing up.

[0006] Therefore, an object of the present invention is to provide a drive control device for a multi-axle drive electric vehicle that can drive and control a plurality of drive axles with driving forces according to axle load distribution. [Means for solving the problem]

[0007] The drive control device of the present invention is a drive control device for a multi-axle drive electric vehicle having a first drive axle driven and rotated by a first electric motor and a second drive axle driven and rotated by a second electric motor, and is equipped with an axle load distribution change control unit that performs axle load distribution change control to change the axle load distribution between the first drive axle and the second drive axle, and a drive control unit that drives and controls the first electric motor and the second electric motor, and when the axle load distribution change control unit is performing axle load distribution change control, the drive control unit performs driving force change control to change the driving force of the first electric motor and the second electric motor.

[0008] In this drive control device, the axle load distribution change control unit performs axle load distribution change control to change the axle load distribution between the first drive axle and the second drive axle, thereby increasing the ground contact pressure between the wheels of the drive axle with an increased axle load and the road surface. This makes it possible to suppress slippage of a multi-axle drive electric vehicle on rough road surfaces. Furthermore, when the axle load distribution change control unit performs axle load distribution change control, the drive control unit performs drive force change control to change the drive forces of the first electric motor and the second electric motor, so that the multiple drive axles can be drive-controlled with drive force according to the axle load distribution.

[0009] The axle load distribution change control unit may change the axle load distribution between the first and second drive axles so that the axle load of the second drive axle becomes smaller relative to the first drive axle, as the axle load distribution change control, and the drive control unit may make the drive force of the second electric motor smaller than the drive force of the first electric motor, as the drive force change control.

[0010] In this drive control device, the axle load distribution change control unit changes the axle load distribution between the first and second drive axles so that the axle load of the second drive axle is smaller than that of the first drive axle, thereby increasing the ground contact pressure between the wheels of the first drive axle and the road surface. On the other hand, when the axle load distribution change control unit performs the axle load distribution change control, the ground contact pressure between the wheels of the second drive axle and the road surface decreases. However, the drive control unit makes the driving force of the second motor smaller than the driving force of the first motor as the driving force change control, thereby suppressing the idling of the second drive axle. This reduces energy loss and suppresses deterioration of electricity consumption (fuel economy), and also suppresses splashing of water, etc. due to wheel idling.

[0011] The drive control unit may set the drive force of the second electric motor to zero as the drive force change control. In this drive control device, the drive control unit sets the drive force of the second electric motor to zero as the drive force change control, thereby making it possible to prevent slippage of the second drive axle.

[0012] The drive control unit may control the torque of the first motor and the second motor as the driving force of the first motor and the second motor. In this drive control device, the drive control unit controls the torque of the first motor and the second motor, thereby making it possible to appropriately drive and control the first motor and the second motor.

[0013] The drive control unit may set the first required driving force calculated based on the accelerator opening as a first command driving force for driving and controlling the first electric motor, and the second required driving force calculated based on the accelerator opening as a second command driving force for driving and controlling the second electric motor, and set a value smaller than the second required driving force as the second command driving force as the driving force change control. In this drive control device, the drive control unit drives and controls the first electric motor and the second electric motor using the first required driving force and the second required driving force calculated based on the accelerator opening as the first command driving force and the second command driving force, but by setting a value smaller than the second required driving force as the second command driving force as the driving force change control, it is possible to suppress slippage of the second drive axle.

[0014] The drive control unit may set a value larger than the first required drive force as the first command drive force as the drive force change control. In this drive control device, the drive control unit sets a value larger than the first required drive force as the first command drive force as the drive force change control, thereby suppressing a decrease in drive force of the entire multi-axle drive electric vehicle.

[0015] The drive control device may further include a first inverter connected to the first motor and a second inverter connected to the second motor, and the drive control unit drives and controls the first motor by outputting a first command drive force to the first inverter and drives and controls the second motor by outputting a second command drive force to the second inverter. In this drive control device, the drive control unit outputs the first command drive force and the second command drive force to the first inverter and the second inverter, thereby appropriately controlling the drive of the first motor and the second motor, and appropriately changing the drive forces of the first motor and the second motor when the axle load distribution change control unit changes the axle load distribution.

[0016] The multi-axle drive electric vehicle may have a front axle, a rear front axle arranged rearward of the front axle in the vehicle longitudinal direction, and a rear rear axle arranged rearward of the rear front axle in the vehicle longitudinal direction, and the first drive axle may be the rear front axle and the second drive axle may be the rear rear axle. In this drive control device, the axle load distribution change control unit changes the axle load distribution between the rear front axle and the rear rear axle, thereby appropriately suppressing slippage of the multi-axle drive electric vehicle on rough road surfaces. In addition, the drive control unit changes the drive force of the first electric motor that rotates and drives the rear front axle and the second electric motor that rotates and drives the rear rear axle, thereby appropriately suppressing slippage of the rear rear axles when the axle load distribution change control unit changes the axle load distribution.

[0017] When the axle load distribution change control unit ends the axle load distribution change control, the drive control unit may gradually restore the drive forces of the first and second motors changed by the drive force change control. In this drive control device, when the axle load distribution change control unit ends the axle load distribution change control, the drive control unit gradually restores the drive forces of the first and second motors changed by the drive force change control, thereby suppressing a sudden change in behavior of the multi-axle drive electric vehicle.

[0018] The multi-axle drive electric vehicle may further include a first air suspension connected to the first drive axle and a body of the multi-axle drive electric vehicle, and a second air suspension connected to the second drive axle and the body, and the axle load distribution change control unit may change the axle load distribution between the first drive axle and the second drive axle by changing the amount of air supplied to and exhausted from the first air suspension and the second air suspension as the axle load distribution change control. In this drive control device, the axle load distribution change control unit can easily change the axle load distribution between the first drive axle and the second drive axle by changing the amount of air supplied to and exhausted from the first air suspension and the second air suspension. Effect of the Invention

[0019] According to the present invention, it is possible to control the drive of a plurality of drive axles with drive forces according to the axle load distribution. [Brief description of the drawings]

[0020] [Figure 1] 1 is a schematic side view showing a multi-axle drive electric vehicle equipped with a drive control device according to an embodiment. [Diagram 2] 2 is a schematic plan view showing a portion of the multi-axle drive electric vehicle shown in FIG. 1. [Diagram 3] FIG. 2 is a block diagram showing the configuration of a drive control device according to the embodiment. [Figure 4] 5 is a flowchart illustrating an example of a processing operation of the drive control device according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the following description, the same or corresponding elements are designated by the same reference numerals, and duplicated description will be omitted.

[0022] FIG. 1 is a schematic side view showing a multi-axle drive electric vehicle equipped with a drive control device according to an embodiment. FIG. 2 is a schematic plan view showing a part of the multi-axle drive electric vehicle shown in FIG. 1. FIG. 3 is a block configuration diagram showing a drive control device according to an embodiment. As shown in FIGS. 1 to 3, a drive control device 1 according to this embodiment is mounted on a multi-axle drive electric vehicle 2 and performs drive control of the multi-axle drive electric vehicle 2. The multi-axle drive electric vehicle 2 is an electric vehicle having a plurality of drive axles. An electric vehicle is a vehicle that can run by driving an electric motor such as a motor with electric power energy. An electric vehicle may also be capable of running by a drive source other than an electric motor such as an engine. Examples of electric vehicles include hybrid vehicles (HEVs: Hybrid Electric Vehicles), plug-in hybrid vehicles (PHEVs: Plug-in Hybrid Electric Vehicles), fuel cell vehicles (FCEVs: Fuel Cell Electric Vehicles), and electric vehicles (BEVs: Battery Electric Vehicles).

[0023] The multi-axle drive electric vehicle 2 includes a front axle 3, a rear front axle 4, a rear axle 5, a first electric motor 6, a second electric motor 7, a first air suspension 8, a second air suspension 9, an air suspension control unit 10, and a drive control unit 11.

[0024] The front axle 3 is a driven axle located at the front Fr portion in the vehicle longitudinal direction D1 of the multi-axle drive electric vehicle 2. Front wheels 12 are coupled to the front axle 3. The front axle 3 also serves as a steering axle for steering the multi-axle drive electric vehicle 2.

[0025] The rear front axle 4 is a drive axle (first drive axle) arranged in a rear Rr portion in the vehicle longitudinal direction D1 of the multi-axle drive electric vehicle 2. The rear front axle 4 is arranged rearward Rr in the vehicle longitudinal direction D1 from the front axle 3. The rear front wheels 13 are coupled to the rear front axle 4.

[0026] The rear axle 5 is a drive axle (second drive axle) arranged at the rear Rr in the vehicle longitudinal direction D1 of the multi-axle drive electric vehicle 2. The rear axle 5 is arranged rearward Rr in the vehicle longitudinal direction D1 from the rear front axle 4. The rear rear wheels 14 are coupled to the rear axle 5.

[0027] The first electric motor 6 is a rotary electric motor such as a motor. The first electric motor 6 is connected to the rear front axle 4 to rotate the rear front axle 4. A first inverter 15 is connected to the first electric motor 6. The first inverter 15 generates a control signal for rotating the first electric motor 6 based on a command signal from the drive control unit 11.

[0028] The second electric motor 7 is a rotary electric motor such as a motor. The second electric motor 7 is connected to the rear axle 5 to rotate the rear axle 5. A second inverter 16 is connected to the second electric motor 7. The second inverter 16 generates a control signal for rotating the second electric motor 7 based on a command signal from the drive control unit 11.

[0029] The first air suspension 8 is connected to the rear front axle 4 and the vehicle body 2A of the multi-axle drive electric vehicle 2. The first air suspension 8 uses air pressure to support the vehicle body 2A relative to the rear front axle 4 and to cushion impacts from the road surface input to the vehicle body 2A from the rear front axle 4. The first air suspension 8 is also capable of adjusting the height of the vehicle body 2A relative to the rear front axle 4 by supplying and exhausting (supplying and discharging) air. The first air suspension 8 includes, for example, a first air pack (not shown) and a first air supply and exhaust device (not shown) that supplies and exhausts air to and from the first air pack. The first air supply and exhaust device supplies and exhausts air to and from the first air pack based on a command signal from the air suspension control unit 10. The first air supply and exhaust device is, for example, an air pump.

[0030] The second air suspension 9 is connected to the rear axle 5 and the vehicle body 2A of the multi-axle drive electric vehicle 2. The second air suspension 9 uses air pressure to support the vehicle body 2A relative to the rear axle 5 and to cushion shocks from the road surface input to the vehicle body 2A from the rear axle 5. The second air suspension 9 is also capable of adjusting the height of the vehicle body 2A relative to the rear axle 5 by supplying and exhausting (supplying and discharging) air. The second air suspension 9 includes, for example, a second air pack (not shown) and a second air supply and exhaust device (not shown) that supplies and exhausts (supplies and discharges) air to the second air pack. The second air supply and exhaust device draws in and exhausts air to the second air pack based on a command signal from the air suspension control unit 10. The second air supply and exhaust device is, for example, an air pump.

[0031] The air suspension control unit 10 is an electronic control unit (ECU) having a CPU, ROM, RAM, etc. The air suspension control unit 10 performs various controls by loading programs stored in the ROM into the RAM and executing them with the CPU. The air suspension control unit 10 may be composed of a single electronic control unit, or may be composed of multiple electronic control units. Furthermore, the air suspension control unit 10 may be an electronic control unit shared with other control units.

[0032] The air suspension control unit 10 drives and controls the first air suspension 8 and the second air suspension 9. The air suspension control unit 10 performs axle load distribution change control to change the axle load distribution between the rear front axle 4 and the rear rear axle 5. Therefore, the air suspension control unit 10 also functions as an axle load distribution change control that performs axle load distribution change control. The axle load distribution change control is a control for suppressing slippage of the multi-axle drive electric vehicle 2 on an uneven road surface, for example. In other words, when the axle load distribution between the rear front axle 4 and the rear rear axle 5 is changed by the axle load distribution change control, the ground contact pressure between the wheels of the drive axle with the increased axle load and the road surface increases, suppressing slippage of the multi-axle drive electric vehicle 2 on an uneven road surface. In this embodiment, the air suspension control unit 10 performs axle load distribution change control so that the axle load of the rear rear axle 5 is smaller than that of the rear front axle 4. The axle load distribution change control is started, for example, by operating the axle load distribution change control switch 17 provided on the multi-axle drive electric vehicle 2, and is ended by releasing the operation of the axle load distribution change control switch 17.

[0033] The air suspension control unit 10 performs the axle load distribution change control, for example, by controlling the driving of the first air suspension 8 and the second air suspension 9. To explain in detail, when the amount of air intake and exhaust changes between the first air suspension 8 and the second air suspension 9, the length of the first air pack and the second air pack in the vehicle vertical direction D2 changes, and the axle load distribution between the rear front axle 4 and the rear rear axle 5 changes. For this reason, the air suspension control unit 10 performs the axle load distribution change control by changing the amount of air intake and exhaust between the first air suspension 8 and the second air suspension 9. In this embodiment, the air suspension control unit 10 reduces the axle load of the rear rear axle 5 relative to the rear front axle 4 by discharging air from the second air suspension 9 as the axle load distribution change control. Note that the air suspension control unit 10 may also reduce the axle load of the rear rear axle 5 relative to the rear front axle 4 by supplying air to the first air suspension 8 as the axle load distribution change control. In addition, the air suspension control unit 10 may reduce the axle load of the rear rear axle 5 relative to the rear front axle 4 by discharging air from the second air suspension 9 and supplying air to the first air suspension 8 .

[0034] The drive control unit 11 is an electronic control unit (ECU) having a CPU, a ROM, a RAM, etc. In the drive control unit 11, a program stored in the ROM is loaded into the RAM and executed by the CPU, thereby executing various controls. The drive control unit 11 may be configured by a single electronic control unit, or may be configured by multiple electronic control units. Furthermore, the drive control unit 11 may be an electronic control unit shared with other control units.

[0035] The drive control unit 11 controls the drive of the rear front axle 4 and the rear rear axle 5. When the air suspension control unit 10 is performing the axle load distribution change control, the drive control unit 11 performs the drive force change control to change the drive forces of the first electric motor 6 and the second electric motor 7. In this embodiment, as the drive force change control, the drive force of the second electric motor 7 is made smaller than the drive force of the first electric motor 6. Note that the drive control unit 11 may set the drive force of the second electric motor 7 to zero as the drive force change control. When the air suspension control unit 10 ends the axle load distribution change control, the drive control unit 11 may restore the drive forces of the first electric motor 6 and the second electric motor 7 changed by the drive force change control all at once, but it is preferable to gradually restore the drive forces of the first electric motor 6 and the second electric motor 7 changed by the drive force change control. In this case, for example, the drive forces of the first electric motor 6 and the second electric motor 7 may be gradually restored at a constant rate, or the drive forces of the first electric motor 6 and the second electric motor 7 may be gradually restored at a variable rate.

[0036] The driving forces of the first electric motor 6 and the second electric motor 7 can be expressed by the torque of the first electric motor 6 and the second electric motor 7, or the rotation speeds of the first electric motor 6 and the second electric motor 7. In this embodiment, the drive control unit 11 controls the torque of the first electric motor 6 and the second electric motor 7 as the driving forces of the first electric motor 6 and the second electric motor 7.

[0037] The drive control unit 11, for example, outputs a first command torque (first command driving force) for driving and controlling the first electric motor 6 to the first inverter 15, and outputs a second command torque (second command driving force) for driving and controlling the second electric motor 7 to the second inverter 16, thereby controlling the driving of the first electric motor 6 and the second electric motor 7. To explain in detail, the drive control unit 11 calculates a first required torque (first required driving force) corresponding to the first electric motor 6 and a second required torque (second required driving force) corresponding to the second electric motor 7 based on the accelerator opening of the multi-shaft drive electric vehicle 2. The drive control unit 11, for example, calculates a required torque of the entire multi-shaft drive electric vehicle 2 based on the accelerator opening of the multi-shaft drive electric vehicle 2, and sets half the value of the required torque of the entire multi-shaft drive electric vehicle 2 as each of the first required torque and the second required torque. The required torque of the entire multi-shaft drive electric vehicle 2 based on the accelerator opening of the multi-shaft drive electric vehicle 2 can be calculated by various known methods. The first required torque and the second required torque may be calculated based not only on the accelerator opening of the multi-axle drive electric vehicle 2 but also on other information such as the rotation speed of the first electric motor 6 and the rotation speed of the second electric motor 7.

[0038] When the air suspension control unit 10 is not performing axle load distribution change control, the drive control unit 11 outputs the calculated first required torque as a first command torque to the first inverter 15, and outputs the calculated second required torque as a second command torque to the second inverter 16. As a result, a control signal corresponding to the first command torque is output from the first inverter 15 to the first electric motor 6, so that the first electric motor 6 is driven to rotate to obtain the first command torque. Also, a control signal corresponding to the second command torque is output from the second inverter 16 to the second electric motor 7, so that the second electric motor 7 is driven to rotate to obtain the second command torque.

[0039] On the other hand, when the air suspension control unit 10 is performing axle load distribution change control, the drive control unit 11 outputs the calculated first required torque as a first command torque to the first inverter 15 and outputs a value smaller than the calculated second required torque as a second command torque to the second inverter 16 as a driving force change control. For example, the drive control unit 11 may set a value smaller than the calculated second required torque as a second limited required torque and output the second limited required torque as the second command torque to the second inverter 16. Note that the drive control unit 11 may set the second command torque to zero as the driving force change control. Then, when the air suspension control unit 10 ends the axle load distribution change control, the drive control unit 11 gradually increases the second command torque output to the second inverter 16 back to the second required torque.

[0040] Next, an example of the processing operation of the drive control device 1 according to the embodiment will be described. Fig. 4 is a flowchart showing an example of the processing operation of the drive control device according to the embodiment. The processing operation shown in Fig. 4 is started, for example, by starting the system of the multi-axle drive electric vehicle 2 when the key is turned ON, and ends when the system of the multi-axle drive electric vehicle 2 is turned off when the key is turned OFF.

[0041] 4, the drive control device 1 first calculates a first required torque corresponding to the first electric motor 6 and a second required torque corresponding to the second electric motor 7 based on the accelerator opening, the rotation speed of the first electric motor 6, the rotation speed of the second electric motor 7, etc. of the multi-axle drive electric vehicle 2 (step S1). Then, the drive control device 1 determines whether the air suspension control unit 10 is executing axle load distribution change control (step S2).

[0042] When it is determined that the air suspension control unit 10 is executing the axle load distribution change control (step S2: YES), the drive control unit 1 sets a value smaller than the second required torque calculated in step S1 as the second limited required torque as the driving force change control (step S3). The second limited required torque is, for example, zero. Next, the drive control unit 1 substitutes the first required torque calculated in step S1 for the first command torque and substitutes the second limited required torque for the second command torque (step S4). Next, the drive control unit 1 transmits the first command torque to the first inverter 15 and transmits the second command torque to the second inverter 16 (step S5). As a result, the first electric motor 6 is driven to rotate so as to achieve the first required torque, and the second electric motor 7 is driven to rotate so as to achieve the second limited required torque. Then, the drive control unit 1 returns to step S1 and repeats the above process.

[0043] In the above step S2, when it is determined that the air suspension control unit 10 has not executed the axle load distribution change control (step S2: NO), the drive control unit 1 determines whether or not the air suspension control unit 10 has previously executed the axle load distribution change control and the second limit required torque has not returned to the second required torque (step S6). When it is determined that the air suspension control unit 10 has previously executed the axle load distribution change control and the second limit required torque has not returned to the second required torque (step S6: YES), the drive control unit 1 gradually returns the second limit required torque to the second required torque calculated in step S1. Next, the drive control unit 1 substitutes the first required torque calculated in step S1 for the first command torque and substitutes the second limit required torque for the second command torque (step S4). Next, the drive control unit 1 transmits the first command torque to the first inverter 15 and transmits the second command torque to the second inverter 16 (step S5). As a result, the first electric motor 6 is driven to rotate at the first required torque, and the second electric motor 7 is driven to rotate at the second limited required torque which is gradually returned to the second required torque. Then, the drive control device 1 returns to step S1 and repeats the above process.

[0044] In the above step S6, if it is determined that the air suspension control unit 10 has not previously executed the axle load distribution change control or that the second limit required torque has returned to the second required torque (step S6: NO), the drive control unit 1 substitutes the first required torque calculated in step S1 for the first command torque and substitutes the second required torque calculated in step S1 for the second command torque (step S7). Next, the drive control unit 1 transmits the first command torque to the first inverter 15 and transmits the second command torque to the second inverter 16 (step S5). As a result, the first electric motor 6 is driven to rotate so as to achieve the first required torque, and the second electric motor 7 is driven to rotate so as to achieve the second required torque. Then, the drive control unit 1 returns to step S1 and repeats the above process.

[0045] As described above, in the drive control device 1 according to this embodiment, the air suspension control unit 10 performs axle load distribution change control to change the axle load distribution between the rear-front axles 4 and the rear-rear axles 5, thereby increasing the ground contact pressure between the wheels of the drive axle with an increased axle load and the road surface. This makes it possible to suppress slippage of the multi-axle drive electric vehicle 2 on rough road surfaces. When the air suspension control unit 10 performs axle load distribution change control, the drive control unit 11 performs drive force change control to change the drive forces of the first electric motor 6 and the second electric motor 7, so that the multiple drive axles can be drive-controlled with drive force according to the axle load distribution.

[0046] In the drive control device 1, the air suspension control unit 10 performs axle load distribution change control to change the axle load distribution between the rear front axle 4 and the rear rear axle 5 so that the axle load of the rear rear axle 5 is smaller than that of the rear front axle 4, thereby increasing the ground contact pressure between the rear front wheels 13 and the road surface. On the other hand, when the air suspension control unit 10 performs axle load distribution change control, the ground contact pressure between the rear rear wheels 14 and the road surface decreases. However, the drive control unit 11 performs driving force change control to make the driving force of the second electric motor 7 smaller than the driving force of the first electric motor 6, thereby suppressing the idling of the rear rear axle 5. This reduces energy loss and suppresses deterioration of electricity consumption (fuel economy), and also suppresses splashing of water, etc. due to the idling of the rear rear wheels 14.

[0047] Furthermore, in the drive control device 1, the drive control section 11 sets the drive force of the second electric motor 7 to zero as drive force change control, thereby making it possible to prevent the rear axle 5 from spinning.

[0048] Moreover, in the drive control device 1, the drive control section 11 controls the torque of the first electric motor 6 and the second electric motor , so that the first electric motor 6 and the second electric motor can be appropriately controlled.

[0049] Furthermore, in the drive control device 1, the drive control unit 11 drives and controls the first electric motor 6 and the second electric motor 7 using the first required torque (first required driving force) and the second required torque (second required driving force) calculated based on the accelerator opening as the first command torque (first command driving force) and the second command torque (second command driving force), but by setting the second command torque to a value smaller than the second required torque as a driving force change control, it is possible to suppress spinning of the rear axle 5.

[0050] Furthermore, in the drive control device 1, the drive control section 11 sets a value larger than the first required torque as the first command torque as the drive force change control, so that a decrease in the drive force of the entire multi-axle drive electric vehicle 2 can be suppressed.

[0051] Furthermore, in the drive control device 1, the drive control unit 11 outputs a first command torque and a second command torque to the first inverter 15 and the second inverter 16, thereby enabling the first electric motor 6 and the second electric motor 7 to be appropriately driven and controlled, and when the air suspension control unit 10 changes the axle load distribution, the drive forces of the first electric motor 6 and the second electric motor 7 can be appropriately changed.

[0052] Furthermore, in the drive control device 1, the air suspension control unit 10 changes the axle load distribution between the rear-front axle 4 and the rear-rear axle 5, thereby making it possible to appropriately suppress slippage of the multi-axle drive electric vehicle 2 on rough road surfaces. Furthermore, the drive control unit 11 changes the driving forces of the first electric motor 6 that rotates and drives the rear-front axle 4 and the second electric motor 7 that rotates and drives the rear-rear axle 5, thereby making it possible to appropriately suppress spinning of the rear-rear axle 5 when the air suspension control unit 10 changes the axle load distribution.

[0053] In addition, in the drive control device 1, when the air suspension control unit 10 ends the axle load distribution change control, the drive control unit 11 gradually restores the driving forces of the first electric motor 6 and the second electric motor 7 that have changed due to the driving force change control, thereby suppressing sudden changes in the behavior of the multi-axle drive electric vehicle 2.

[0054] In addition, in the drive control device 1, the air suspension control unit 10 can easily change the axle load distribution between the rear front axle 4 and the rear rear axle 5 by changing the amount of air supplied to and exhausted from the first air suspension 8 and the second air suspension 9.

[0055] Although an embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and may be modified or applied to other things without departing from the gist of the claims.

[0056] For example, in the above embodiment, the multi-axle drive electric vehicle has been described as having one driven axle and two drive axles, but the number of driven axles and drive axles is not particularly limited as long as it has two or more drive axles. [Explanation of symbols]

[0057] 1...drive control device, 2...multi-axle drive electric vehicle, 2A...vehicle body, 3...front axle, 4...rear front axle, 5...rear rear axle, 6...first electric motor, 7...second electric motor, 8...first air suspension, 9...second air suspension, 10...air suspension control unit (axle load distribution change control unit), 11...drive control unit, 12...front wheel, 13...rear front wheel, 14...rear rear wheel, 15...first inverter, 16...second inverter, 17...axle load distribution change control switch, D1...fore-and-aft direction of vehicle, D2...up-and-down direction of vehicle.

Claims

1. 1. A drive control device for a multi-axle drive electric vehicle including a first drive axle that is rotationally driven by a first electric motor and a second drive axle that is rotationally driven by a second electric motor, an axle load distribution change control unit that performs an axle load distribution change control to change an axle load distribution between the first driving axle and the second driving axle; a drive control unit that controls the drive of the first electric motor and the second electric motor, The drive control unit performs a driving force change control to change the driving forces of the first electric motor and the second electric motor when the axle load distribution change control unit performs the axle load distribution change control. Drive control device.

2. The axle load distribution change control unit changes an axle load distribution between the first drive axle and the second drive axle so that an axle load of the second drive axle is smaller than that of the first drive axle, The drive control unit, as the driving force change control, makes the driving force of the second electric motor smaller than the driving force of the first electric motor. The drive control device according to claim 1.

3. The drive control unit sets the drive force of the second electric motor to zero as the drive force change control. The drive control device according to claim 2.

4. The drive control unit controls torque of the first motor and the second motor as driving forces of the first motor and the second motor. The drive control device according to claim 2 or 3.

5. The drive control unit is a first required driving force calculated based on an accelerator opening degree is a first command driving force for driving and controlling the first electric motor, and a second required driving force calculated based on the accelerator opening degree is a second command driving force for driving and controlling the second electric motor, In the driving force change control, a value smaller than the second requested driving force is set as the second command driving force. The drive control device according to any one of claims 2 to 4.

6. The drive control unit sets the first command drive force to a value greater than the first requested drive force as the drive force change control. The drive control device according to claim 5.

7. a first inverter connected to the first motor; A second inverter connected to the second motor, The drive control unit drives and controls the first electric motor by outputting the first command drive force to the first inverter, and drives and controls the second electric motor by outputting the second command drive force to the second inverter. The drive control device according to claim 5 or 6.

8. the multi-axle drive electric vehicle includes a front axle, a rear front axle arranged rearward of the front axle in a vehicle longitudinal direction, and a rear rear axle arranged rearward of the rear front axle in the vehicle longitudinal direction, the first drive axle is the rear front axle; The second drive axle is the rear axle. The drive control device according to any one of claims 2 to 7.

9. When the axle load distribution change control unit ends the axle load distribution change control, the drive control unit gradually restores the drive forces of the first electric motor and the second electric motor that have been changed by the drive force change control. The drive control device according to any one of claims 1 to 8.

10. a first air suspension connected to the first drive axle and a body of the multi-axle drive electric vehicle; a second air suspension coupled to the second drive axle and the vehicle body; The axle load distribution change control unit changes the axle load distribution between the first driving axle and the second driving axle by changing the amount of air supplied to and exhausted from the first air suspension and the second air suspension as the axle load distribution change control. The drive control device according to any one of claims 1 to 9.

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