JP7287763B2 - power transmission controller - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission control device for a vehicle having wheels, drive shafts for transmitting power from a drive source to the wheels, and brake mechanisms for the wheels. It relates to the technical field for controlling.

For example, as disclosed in Patent Document 1 below, some 4WD vehicles (four-wheel drive vehicles) are capable of switching from 4WD to 2WD (two-wheel drive) in order to improve fuel efficiency (fuel consumption rate). . For example, switching from 4WD to 2WD includes switching from an all-wheel drive state in which all front, rear, left, and right wheels are driven to a front-wheel drive state in which only the front wheels are driven.

When switching from 4WD to the front-wheel drive state, the power transmission between the propeller shaft for transmitting power to the rear wheels and the drive source is disconnected.
However, if the power transmission between the drive source and the propeller shaft is cut off in this way, the drive shaft on the rear wheel side and the rear differential unit (hereinafter abbreviated as "rear differential unit") will not work as the rear wheels rotate. ), and the propeller shaft will be rotated. Since these rotations are accompanied by oil churning resistance and the like, they act as resistance components when the rear wheels rotate. That is, the resistance component increases the running resistance of the vehicle in the front-wheel drive state, and acts as one of the causes of deterioration in fuel consumption.

Therefore, as disclosed in Patent Document 1 below, during 2WD driving, not only is the power transmission between the drive source and the propeller shaft disconnected, but also, for example, two left and right clutches provided in the rear differential unit By disconnecting the power transmission between the rear wheels, the rotation of the gear mechanism and propeller shaft in the rear differential unit is stopped, reducing the running resistance of the rear wheels as described above and further improving fuel efficiency. can be planned.

JP 2016-30477 A

However, in the configuration in which the clutch is provided in the rear differential unit as described above, the drive shafts connected to the rear wheels rotate as the rear wheels rotate even when the clutch is disengaged. In the rear differential unit in this case, of the pair of fastening members (friction plates) in the clutch, the fastening member on the side connected to the drive shaft rotates as the rear wheel rotates. Therefore, in this case, the oil churning resistance in the rear differential unit case accompanying the rotation of the fastening member acts as a rotational resistance component on the rear wheel, and the rotational resistance of the drive shaft also acts as a rotational resistance component. It will be.
That is, these resistance components still act as running resistance of the vehicle during 2WD running, and there is room for improvement in fuel efficiency.

In addition, in the configuration in which the clutch is provided in the rear differential unit as described above, it is necessary to secure a space for arranging the left and right clutches in the rear differential unit, which leads to an increase in the size of the rear differential unit in the left and right direction. become.
If the lateral size of the rear differential unit increases, the length of the drive shaft must be shortened under the assumption that the width of the vehicle is kept constant. However, when the drive shaft is shortened, the movable range of the wheels connected to the drive shaft (mainly the vertical movable range) also tends to be reduced. In the case of designing undercarriage such as a suspension mechanism, there is a possibility that the degree of freedom in design may be reduced.

The present invention has been made in view of the above circumstances. For example, it realizes the extension of the mileage of the vehicle by improving the fuel efficiency, etc., and the improvement of the degree of freedom in the design of the undercarriage of the vehicle, while reducing the number of parts and the cost. intended to

A power transmission control device according to the present invention is a power transmission control device for a vehicle having wheels, a drive shaft for transmitting power input from a drive source through a differential mechanism to the wheels, and a brake mechanism for the wheels. An intermittent mechanism that can intermittently interrupt power transmission from the drive shaft to the wheels; and an intermittent switching mechanism that switches between intermittent power transmission by the intermittent mechanism using brake pressure that operates the brake mechanism as a power source. and

By arranging the intermittent mechanism on the output side (wheel side) of the drive shaft, the drive shaft does not rotate according to the wheel rotation when the intermittent mechanism is disconnected (power transmission is interrupted). Also, by arranging the disconnecting mechanism on the output side of the drive shaft, the differential unit can be made smaller than the conventional example in which the disconnecting mechanism is provided in the differential unit.
Furthermore, by using the brake pressure for power intermittent switching for the wheels, the intermittent mechanism and the intermittent switching mechanism can be easily arranged at positions closer to the wheels. Further, by using the brake pressure for intermittent switching of power to the wheels, it is not necessary to add a new pressure supply source for intermittent switching.

In the power transmission control device according to the present invention described above, the connection/disconnection switching mechanism switches the state of the connection/disconnection mechanism to a state in which the power is transmitted when the brake pressure becomes relatively high, It is possible to adopt a configuration in which the state of the disconnecting mechanism is switched to a state in which the power transmission is disconnected when the pressure becomes relatively low.

When the brake pressure becomes high, the connection/disconnection mechanism is brought into a state of transmitting power to the wheels, that is, the connection/disconnection mechanism is brought into a engaged state, so that it is easy to secure the connection force.

In the power transmission control device according to the present invention described above, the connection/disconnection switching mechanism switches the state of the connection/disconnection mechanism to a state in which the power is transmitted when the brake pressure becomes relatively low, It is possible to adopt a configuration in which the state of the disconnecting mechanism is switched to a state in which the power transmission is disconnected when the pressure becomes relatively high.

As a result, it is possible to eliminate the need to apply brake pressure to the intermittent switching mechanism when bringing the intermittent mechanism into the power transmission state. Therefore, even when the vehicle is in a non-starting state such as when the engine of the vehicle is stopped, the connecting/disconnecting mechanism can be maintained in the power transmission state.

In the power transmission control device according to the present invention described above, the connecting/disconnecting mechanism may be configured by a dry clutch.

This makes it possible to reduce the size of the connecting/disconnecting mechanism (compared to a wet clutch).

In the power transmission control device according to the present invention, the vehicle has at least two drive shaft pairs in the front-rear direction, each of which is a pair of left and right drive shafts. It is possible to have a configuration that

As a result, it is possible to independently control the intermittence of power transmission for each of the wheels spaced apart in the front, rear, left, and right directions.

According to the present invention, it is possible to extend the travelable distance of a vehicle by improving fuel efficiency, etc., and improve the degree of freedom in designing the underbody of the vehicle, while reducing the number of parts and cost.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram illustrating a schematic configuration of a drive system for wheels of a vehicle equipped with a power transmission control device as an embodiment of the present invention; FIG. 10 is an explanatory diagram of a conventional rear differential unit; FIG. 4 is an explanatory diagram of an intermittent mechanism included in the power transmission control device as an embodiment; 1 is a diagram showing a schematic configuration example of a power transmission control device as an embodiment; FIG. 4 is a flowchart showing brake interlock switching processing in the embodiment. 4 is a flow chart showing request torque interlocking switching processing in the embodiment. It is the flowchart which showed the fixed driving|running|working interlocking switching process in embodiment. It is a figure showing an example of outline composition of a power transmission control device as a modification. It is the flowchart which showed the brake interlocking switching process in a modification. 9 is a flow chart showing request torque interlocking switching processing in a modified example. It is the flowchart which showed the fixed driving|running|working interlock switching process in a modification.

<1. Configuration of Power Transmission Control Device as Embodiment>
A power transmission control device as an embodiment according to the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a diagram illustrating a schematic configuration of a drive system for wheels of a vehicle 100 equipped with a power transmission control device as an embodiment.
The vehicle 100 of this example is configured as a four-wheel drive vehicle having a pair of left and right front wheels 50L and 50R as main drive wheels and a pair of left and right rear wheels 50L and 50R as auxiliary drive wheels. Also, the vehicle is provided with an engine 101 as a drive source for the wheels.
In this embodiment, "L" and "R" in the reference numerals respectively mean the left side and the right side with respect to the traveling direction of the vehicle when moving forward.

The vehicle 100 includes a transmission 102, a front differential mechanism 103, drive shafts 104L and 104R, a driving force intermittent portion 105, and a driving force transmission system capable of transmitting the driving force of the engine 101 to the front wheels 50L and 50R and the rear wheels 51L and 51R. It has a propeller shaft 106, a rear differential unit 107, drive shafts 108L and 108R, and clutch mechanisms 30L and 30R.
This driving force transmission system has a four-wheel drive state (hereinafter also referred to as a "4WD state") in which the driving force of the engine 101 is transmitted to the front wheels 50L, 50R and the rear wheels 51L, 51R, and the driving force of the engine 101. can be switched between a two-wheel drive state (hereinafter also referred to as a "2WD state") in which the power is transmitted only to the front wheels 50L and 50R.

The driving force of engine 101 is transmitted to front differential mechanism 103 via transmission 102 . The front differential mechanism 103 has side gears 103L and 103R, a pinion gear 103a, a pinion shaft 103b, and a front differential case 103c, and is arranged between the transmission 102 and the driving force intermittent portion 105. The side gear 103L is connected to the front wheel side drive shaft 104L, and the side gear 103R is connected to the front wheel side drive shaft 104R.

In the front differential mechanism 103, the front differential case 103c rotates as the output shaft of the transmission 102 rotates. The pinion shaft 103b rotates integrally with the front differential case 103c, the pinion gear 103a rotates with the rotation of the pinion shaft 103b, and the rotation is transmitted to the side gears 103L and 103R meshing with the pinion gear 103a. As a result, the driving force of the engine 101 is transmitted to the drive shafts 104L and 104R through the transmission 102 and the front differential mechanism 103, and the front wheels 50L and 50R connected to the drive shafts 104L and 104R are driven.

The driving force interrupting portion 105 includes a first spline tooth portion 105a that rotates integrally with the front differential case 103c, a second spline tooth portion 105b that rotates integrally with the ring gear 105e, the first spline tooth portion 105a, and the second spline tooth portion 105b. and a drive pinion 105f that meshes with the ring gear 105e and rotates integrally with the propeller shaft 106. The ring gear 105e and the drive pinion 105f constitute a gear mechanism 105d on the front wheel side.
The sleeve 105c is moved axially of the first spline tooth portion 105a and the second spline tooth portion 105b by an actuator (not shown) controlled by an ECU (Electronic Control Unit) as a transmission control portion 11 (described later) of the vehicle 100. It is possible to move forward and backward. That is, the driving force intermittent portion 105 can transmit the driving force from the engine 101 to the propeller shaft 106 by connecting the first spline tooth portion 105a and the second spline tooth portion 105b by the sleeve 105c so as not to rotate relative to each other. It is configured to have a dog clutch (meshing clutch) that makes it possible.

The rear differential unit 107 has a pinion gear 107a that rotates together with the propeller shaft 106, a ring gear 107b that meshes with the pinion gear 107a, a rear differential shaft 107c that rotates together with the ring gear 107b, and a rear differential case 107d.
The propeller shaft 106 has a rotation axis substantially in the longitudinal direction of the vehicle 100, while the rear differential shaft 107c has a rotation axis substantially in the lateral direction of the vehicle. The rear differential case 107d accommodates the pinion gear 107a and the ring gear 107b inside, and supports the rear end of the propeller shaft 106 and both left and right ends of the rear differential shaft 107c.

In rear differential unit 107, the rotational force of propeller shaft 106 is transmitted to rear differential shaft 107c via pinion gear 107a and ring gear 107b, and rear differential shaft 107c is rotated.

The right end of the drive shaft 108L is connected to the left end of the rear differential shaft 107c, and the left end of the drive shaft 108R is connected to the right end of the rear differential shaft 107c.

The clutch mechanism 30L is interposed between the drive shaft 108L and the rear wheel 51L, and the clutch mechanism 30R is interposed between the drive shaft 108R and the rear wheel 51R.
The clutch mechanisms 30L and 30R will be explained again.

In the driving force transmission system of the vehicle 100 configured as described above, when 4WD driving is to be performed, the transmission control unit 11 controls the sleeve 105c of the driving force intermittent portion 105 so that the first spline tooth portion 105a and the second spline tooth portion 105a are connected. It is driven to a position where the two spline tooth portions 105b are connected so as not to rotate relative to each other. As a result, a state is realized in which driving force can be transmitted from the engine 101 to the propeller shaft 106 . Further, as will be described later, when 4WD driving is to be performed, control is performed so that the clutch mechanisms 30L and 30R provided on the rear wheel 51 side are engaged. That is, the driving force transmitted from the engine 101 via the propeller shaft 106 can be transmitted to the rear wheels 50L and 50R via the rear differential unit 107 and the left and right drive shafts 108L and 108R.
As a result, a 4WD state in which the front wheels 50L and 50R as main drive wheels and the rear wheels 50L and 50R are rotationally driven by the driving force of the engine 101 is realized.

On the other hand, when 2WD running is to be performed, the sleeve 105c is driven to a position where the first spline tooth portion 105a and the second spline tooth portion 105b are allowed to rotate relative to each other under the control of the transmission control section 11, whereby the engine is driven. Transmission of driving force from 101 to propeller shaft 106 is disabled. Further, when 2WD driving is to be performed, as will be described later, control is performed so that the clutch mechanisms 30L and 30R are not engaged, and the driving force transmitted from the engine 101 via the propeller shaft 106 is transmitted to the rear wheels. 50L and 50R are in a non-transmissible state.
Therefore, a 2WD state in which only the front wheels 50L and 50R as main drive wheels are rotationally driven by the driving force of the engine 101 is realized.

Here, as described above, during 2WD, transmission of driving force from the engine 101 to the propeller shaft 106 is cut off by the driving force intermittence section 105, and transmission of torque from the rear wheels 51L, 51R to the propeller shaft 106 is stopped by the clutch. They are blocked by mechanisms 30L and 30R, respectively. This stops the rotation of propeller shaft 106 even when vehicle 100 is running. Therefore, the rotation of the gear mechanism 105d in the driving force intermittence section 105 and the pinion gear 107a and ring gear 107b in the rear differential unit 107 are also stopped, and the stirring resistance of the lubricating oil in these sections is reduced.

In this embodiment, the clutch mechanisms 30L and 30R are arranged between the drive shaft 108L and the rear wheel 51L and between the drive shaft 108R and the rear wheel 51R, respectively.
As a result, during 2WD running, that is, during running with the clutch mechanisms 30L and 30R disconnected, the drive shafts 108L and 108R do not rotate according to the rotation of the rear wheels 51L and 51R, thereby reducing friction loss. , fuel efficiency is improved.

Further, by providing the clutch mechanism 30 between the drive shaft 108 and the rear wheel 51, the size of the rear differential unit 107 can be reduced compared to the conventional example in which the clutch mechanism 30 is provided inside the rear differential unit 107.
Conventionally, the clutch mechanism 30 used for switching between 2WD and 4WD was provided in the rear differential unit 107 as disclosed in the above-mentioned Patent Document 1.
FIG. 2 shows an example of a rear differential unit 107' provided with clutch mechanisms 30L and 30R. As is clear from FIG. 2, when the clutch mechanisms 30L and 30R are provided in the rear differential unit 107', the size of the rear differential unit 107' is increased (increased size in the left-right direction).
Further, if the rear differential unit 107' is enlarged, under the premise that the width of the vehicle 100 is kept constant, the length of the drive shafts 108L and 108R must be shortened. When the drive shafts 108L and 108R are shortened, the range of motion (mainly the range of motion in the vertical direction) of the rear wheels 51L and 51R also tends to be reduced, which may lead to a reduction in the degree of freedom in undercarriage design.

According to this embodiment, the size of the rear differential unit 107 can be reduced, and the drive shafts 108L and 108R can be lengthened without increasing the width of the vehicle. can be expanded, and the degree of freedom in designing the chassis of the vehicle 100 can be improved.

In the above description, a so-called horizontal transmission layout in which the transmission 102 is arranged on the side of the engine 101 is illustrated, but a so-called vertical transmission layout in which the transmission 102 is arranged behind the engine 101 is used. Layout can also be adopted. In that case, the front differential mechanism 103 is connected to the output shaft of the transmission 102 via, for example, a propeller shaft for the front wheels.

FIG. 3 is an explanatory diagram of the clutch mechanisms 30L and 30R.
Note that FIG. 3 shows the structure of the clutch mechanism 30R as a representative, and the structure of the clutch mechanism 30L is the same as that of the clutch mechanism 30R, so the explanation by illustration is omitted.
In FIG. 3, only the structure of the main part related to the clutch mechanism 30R is extracted and shown with respect to the structure in the vicinity of the rear wheel 51R. The cross-sectional structure when cut in the vertical direction at a position passing through the rotation axis of the ring 51R is schematically shown. As for the rear wheel 51R, only the wheel 51Rw portion is extracted and shown, excluding the tire portion.

The clutch mechanism 30R has a pressure plate 31 and a clutch plate 32, and is configured as a friction clutch in which power is transmitted by frictional engagement between the pressure plate 31 and the clutch plate 32. As shown in FIG. The pressure plate 31 is spline-fitted to the right end portion 108Ra of the drive shaft 108R, and is displaceable in the rotational axis direction of the right end portion 108Ra.
In addition, the pressure plate 31 is driven in the rotation axis direction by a lever 34 which will be described later.
The clutch mechanism 30R in this example is a dry clutch mechanism that is not lubricated with lubricating oil.

In this example, the pressure plate 31 and the clutch plate 32 in the clutch mechanism 30R are housed inside the hub knuckle 40 . The hub knuckle 40 is a member supported from the vehicle body frame side of the vehicle 100 via a suspension mechanism (not shown) or the like. Although not shown, the hub knuckle 40 is attached with a brake caliper that constitutes a brake mechanism for the rear wheel 51R.
The hub knuckle 40 supports the right end 108Ra of the drive shaft 108R and supports the hub 33 to which the brake rotor 41 is attached as shown. The hub 33 has a left end connected to the clutch plate 32 and rotates together with the clutch plate 32 .

The center of rotation of the brake rotor 41 protrudes rightward, and the tip surface of the protruded portion serves as a mounting surface for the wheel 51Rw. The wheel 51Rw is attached to the brake rotor 41 with a fastening member such as a bolt while the attachment surface provided near the center of rotation and the attachment surface of the brake rotor 41 are in contact with each other.

By providing the clutch mechanism 30R (and the clutch mechanism 30L) as described above, the clutch mechanism 30R (and the clutch mechanism 30L) is brought into a non-engaged state during 2WD running in which only the front wheels 50R and 50L are driven. , the power transmission between the rear wheel 51R (51L) and the drive shaft 108R (108L) is cut off.
As a result, the rotational resistance of the drive shaft 108R (108L) is prevented from acting as running resistance of the vehicle 100 through the rear wheels 51R (51L). Extension of the travelable distance of the vehicle 100 can be achieved.

Here, in this embodiment, switching between engagement/non-engagement of the clutch mechanisms 30L and 30R as described above is performed based on the brake pressure for operating the brake mechanism of the wheel.

FIG. 4 shows a schematic configuration example of the power transmission control device 1 as an embodiment, including the configuration of the brake control system for controlling the wheel brake mechanism.
As illustrated, the power transmission control device 1 includes an intermittent control unit 10, a transmission control unit 11, a brake control unit 12, and a bus 13, each of which is configured as an ECU. A valve 22, a second supply passage R4, a hydraulic chamber 23, a piston 24, and a lever 34 are provided.
The clutch mechanism 30R (and 30L) already described is also one of the elements constituting the power transmission control device 1. As shown in FIG.

First, the configuration of the brake control system will be described.
The brake control system of this example employs a configuration that generates hydraulic pressure from the brake fluid as the brake pressure to be applied to the wheel brake mechanism (brake caliper in this example). Specifically, the brake control system includes a master cylinder 20, which is a hydraulic pressure source that generates a brake fluid pressure corresponding to the force applied to a brake pedal BP provided in the vehicle 100, and a brake fluid pressure generated in the master cylinder 20. an input path R1 to which is input, a hydraulic pressure adjustment unit 21 to which the brake fluid pressure is input via the input path R1, an output path R2 to which the brake fluid pressure output from the fluid pressure adjustment unit 21 is input, and a first supply path R3 for supplying the brake fluid pressure input via the output path R2 to the cylinder of the brake caliper.
Although the first supply path R3 is provided for each wheel (for each brake caliper), here only the first supply path R3 for supplying the brake fluid pressure to the brake caliper provided for the rear wheel 51R is representatively provided. showing.

The hydraulic pressure adjustment unit 21 includes various electromagnetic valves controlled by the brake control unit 12, a pump (electric pump in this example) for pressurizing the brake fluid pressure, and a brake fluid used for releasing the brake fluid pressure. It is configured to have a reservoir or the like, and the brake fluid pressure can be adjusted based on the control of the brake control unit 12 .

The brake control unit 12 implements ABS (Antilock Brake System) control by controlling the hydraulic pressure adjustment unit 21 . Specifically, the brake control unit 12 performs opening/closing control of a predetermined electromagnetic valve in the fluid pressure adjustment unit 21, thereby switching relatively quickly between the state in which the brake fluid pressure is released to the reservoir and the state in which the brake fluid pressure is not released. repeat. As a result, brake fluid pressure increases/decreases in the cylinder of the brake caliper are repeated at a relatively high speed, thereby implementing brake control as ABS control for preventing wheels from locking.
Further, the brake control unit 12 can operate the above-described pump in the hydraulic pressure adjustment unit 21 to generate brake hydraulic pressure. At this time, it is possible to adjust the generated brake fluid pressure by controlling the rotation speed of the motor that drives the pump.
Since the hydraulic pressure adjusting unit 21 can generate brake hydraulic pressure by the pump in this way, the brake hydraulic pressure can be generated without depending on the operation of the brake pedal BP, and the front wheels 50L and 50R, the rear wheels 51L, It is possible to generate a braking force at 51R.

The intermittent control unit 10 is capable of mutual data communication with the transmission control unit 11 and the brake control unit 12 via the bus 13 .
The connection/disconnection control unit 10 controls at least the control valve 22 to switch engagement/non-engagement of the clutch mechanism 30R, that is, switch connection/disconnection of power transmission between the drive shaft 108R and the hub 33 .

As shown, control valve 22 is interposed between output line R2 and first supply valve R3. The control valve 22 is configured, for example, as a spool-type solenoid valve (eg, solenoid valve), and has an input port 22a, a first output port 22b, and a second output port 22c. The input port 22a is connected to the output line R2, and the first output port 22b is connected to the first supply line R3. The second output port 22c is connected to the second supply path R4 for driving the clutch mechanism 30R.
As shown in the figure, the end of the second supply path R4 on the side opposite to the connection end with the second output port 22c of the control valve 22 forms a fluid pressure chamber 23 for applying brake fluid pressure to the piston 24. are communicated.

The lever 34 is rotatable around a rotation shaft 34a, and has one end in contact with the tip of the piston 24 and the other end facing the rear surface of the pressure plate 31 (clutch plate 32) in the clutch mechanism 30R. The surface located on the opposite side of the frictional engagement surface of the In this example, when the brake hydraulic pressure increases in the hydraulic pressure chamber 23 , the piston 24 is pushed leftward, and the tip pushes one end of the lever 34 . As a result, the lever 34 is rotated counterclockwise in the drawing, and the other end of the lever 34 presses the pressure plate 31 toward the clutch plate 32 . As a result, a state in which the pressure plate 31 is frictionally engaged with the clutch plate 32, that is, a state in which the clutch mechanism 30R is engaged is obtained.
On the other hand, when the brake fluid pressure in the fluid pressure chamber 23 decreases, the pressing force on the piston 24 decreases and the pressing force on the lever 34 also decreases. Therefore, the pressing force of the pressure plate 31 by the lever 34 is also reduced, and the frictional engagement state between the pressure plate 31 and the clutch plate 32 is released. That is, the clutch mechanism 30R will be in a non-engagement state.
In this example, the pressure plate 31 is biased away from the clutch plate 32 by a biasing member (not shown). At the time of frictional engagement with the clutch plate 32, the pressing force of the lever 34 drives the pressure plate 31 toward the clutch plate 32 against the biasing force of the biasing member.

In FIG. 4, only the clutch mechanism 30R is representatively shown as the clutch mechanism 30. In response to the fact that the clutch mechanism 30R is represented as the clutch mechanism 30, the structure (the control valve 22, the second Although only the configuration corresponding to the clutch mechanism 30R is shown for the second supply path R4, the hydraulic pressure chamber 23, the piston 24, and the lever 34), a similar configuration is also provided on the clutch mechanism 30L side. Specifically, a control valve 22, a second supply passage R4, a hydraulic pressure chamber 23, a piston 24, and a lever 34 corresponding to the clutch mechanism 30L are provided.

Here, the control valve 22 is configured to be able to switch communication/non-communication between the input port 22a and the first output port 22b and between the input port 22a and the second output port 22c. Specifically, the control valve 22 has the following first states to It is possible to switch between the third states.
"first state"
A state in which both the input port 22a and the first output port 22b and the input port 22a and the second output port 22c are in communication. That is, a state in which both the first supply path R3 and the second supply path R4 are communicated with the output path R2.
"second state"
A state in which the input port 22a and the first output port 22b are in communication, and the input port 22a and the second output port 22c are not in communication. That is, a state in which only the first supply path R3 is communicated with the output path R2. In addition, in the second state, there is no communication between the first output port 22b and the second output port 22c.
"Third State"
A state in which the input port 22a and the first output port 22b are not in communication, and the input port 22a and the second output port 22c are in communication. That is, a state in which only the second supply path R4 is communicated with the output path R2. In addition, in the third state, there is no communication between the first output port 22b and the second output port 22c.

The intermittent control unit 10 of the present embodiment controls the actuator in the control valve 22 (including the control valve 22 corresponding to the clutch mechanism 30L), so that any state among the above first to third states It is possible to switch to

Here, the intermittence control unit 10 of the present embodiment performs intermittence control of power transmission in the clutch mechanisms 30L and 30R according to the running state of the vehicle 100. FIG.
Specifically, when the vehicle 100 is in a decelerating state with the brakes turned on (the brake pedal BP is stepped on) during 2WD running, the intermittent control unit 10 puts the clutch mechanisms 30L and 30R into the engaged state. control to allow This control is intended to increase the number of wheels to which engine braking is applied during deceleration.
Hereinafter, such control will be referred to as "brake interlock switching control".

Further, when the driver desires to accelerate the vehicle 100 relatively greatly during 2WD running, that is, when the required torque is relatively large, the intermittent control unit 10 engages the clutch mechanisms 30L and 30R. Perform control to set the state. This is intended to obtain a greater acceleration force by increasing the number of drive wheels, and to stabilize the behavior of the vehicle 100 during acceleration, such as preventing wheel slipping.
Hereinafter, such control will be referred to as "requested torque interlocking switching control".

Further, the intermittent control unit 10 determines that the vehicle 100 is cruising in a constant speed range (for example, the running state in the constant speed range has continued for a predetermined time or longer) during 4WD running, and is in a constant running state. In this case, as control in consideration of fuel consumption, control for disengaging the clutch mechanisms 30L and 30R is performed.
Hereinafter, such control will be referred to as "constant running interlock switching control".

Here, in the vehicle 100 of this example, when the clutch mechanisms 30L and 30R are brought into the engaged state by the brake interlocking switching control or the demand torque interlocking switching control as described above, the transmission control unit 11 switches from 2WD to 4WD. control for That is, the control is to drive the sleeve 105c in the driving force intermittence section 105 and transition to a state in which power transmission from the engine 101 to the propeller shaft 106 is possible.
Further, in the vehicle 100 of this example, when the clutch mechanisms 30L and 30R are brought into the non-engagement state by the above-described constant driving interlocking switching control, the transmission control unit 11 performs control for switching from 4WD to 2WD (that is, , drive the sleeve 105c to make a transition to a state in which power transmission from the engine 101 to the propeller shaft 106 is disabled).

<2. Example of intermittent control processing>
Processing to be executed by the intermittent control unit 10 to implement the above-described brake interlocking switching control, requested torque interlocking switching control, and constant running interlocking switching control will be described with reference to the flowcharts of FIGS. 5 to 7 .

FIG. 5 is a flowchart showing a brake interlocking switching process for realizing brake interlocking switching control. The processing shown in FIG. 5 is started under the condition that the vehicle 100 is running in 2WD.
First, the intermittent control unit 10 waits until the brake is turned on (step S101). Whether or not the brake is ON can be determined based on a detection signal of a brake switch (not shown) that is turned ON/OFF depending on whether or not the brake pedal BP is operated.
When the brake is turned ON, the intermittent control unit 10 performs control to bring the control valve 22 into the above-described first state (step S102). That is, the control valve 22 is controlled so that both the input port 22a and the first output port 22b and the input port 22a and the second output port 22c are in communication.
As a result, both the first supply channel R3 and the second supply channel R4 are in communication with the output channel R2 of the hydraulic pressure adjusting unit 21, and the brake hydraulic pressure generated in response to the brake ON is applied to the brake caliper and the hydraulic pressure chamber 23. supplied to both That is, while braking force is applied to the front wheels 50L, 50R and the rear wheels 51L, 51R, the clutch mechanisms 30L, 30R are engaged to apply engine braking to the rear wheels 51L, 51R. status is obtained.

In response to controlling the control valve 22 to the first state as described above, the intermittent control unit 10 waits until the brake is turned off (step S103). When the brake is turned off, the intermittent control unit 10 returns to step S101.
When the brake is turned off, that is, when the force applied to the brake pedal BP is removed, the pressure in the hydraulic pressure chamber 23 is released, and the clutch mechanisms 30L and 30R are switched to the non-engagement state. That is, the state is switched from 4WD to 2WD.
Note that, when it is confirmed in step S103 that the brake is OFF, the control valve 22 may be shifted to the second state (the state in which only the first supply passage R3 is communicated with the output passage R2).

In the above example, the clutch mechanisms 30L and 30R are engaged using only the force applied to the brake pedal BP. In this case, the intermittent control unit 10 sets the control valve 22 to the first state in step S102, and then drives the above-described pump in the fluid pressure adjustment unit 21 to pressurize the brake fluid pressure. At this time, the pressurization instruction is given to the brake control unit 12 .

FIG. 6 is a flow chart showing a request torque interlocking switching process for realizing the request torque interlocking switching control.
Note that the processing shown in FIG. 6 is started on the condition that the value of the required torque (the required torque of the engine 101) becomes equal to or greater than a predetermined value during 2WD running. Whether or not to start the processing shown in FIG. 6 may be determined by the intermittent control unit 10 itself acquiring the value of the required torque. Alternatively, in the present embodiment, the transmission control unit 11 performs 2WD→4WD switching control targeting the driving force intermittence unit 105 during the requested torque interlocking switching control. The intermittent control unit 10 may also start the processing shown in FIG. can.

First, the intermittent control unit 10 performs control to bring the control valve 22 into the third state (step S201). As a result, the brake fluid pressure can be supplied to the second supply path R4 communicating with the hydraulic pressure chamber 23, while the brake fluid pressure can be supplied to the first supply path R3 communicating with the cylinder of the brake caliper. is switched to a disabled state.

Next, the intermittent control unit 10 instructs the brake control unit 12 to turn on the brake pressure. In response to this ON instruction, the brake control unit 12 drives the pump in the fluid pressure adjustment unit 21 to generate brake fluid pressure.
The brake fluid pressure thus generated is supplied to the fluid pressure chamber 23 via the output path R2 and the second supply path R4, and the clutch mechanisms 30L and 30R are switched to the engaged state.

In response to the ON instruction, the intermittent control unit 10 waits until the brake is turned ON or until constant running is detected (steps S203 and S204). That is, the system waits until it is confirmed that the brake pedal BP is stepped on or the above-described constant running state is detected. Whether or not the vehicle is in a constant running state is determined, for example, based on a detection signal from a vehicle speed sensor (not shown), by determining whether or not the vehicle has been running in a constant speed range for a predetermined time or longer. It should be noted that such determination of the constant running state can also be performed by the transmission control unit 11 side. A process for determining whether or not a notification has been received is performed depending on the situation.

When it is confirmed that the brake is ON, the intermittent control unit 10 instructs the brake control unit 12 to stop driving the pump in the hydraulic pressure adjustment unit 21 as an instruction to release the brake pressure ON. move on. As a result, the control valve 22 is switched to the first state when the brake is turned on after the clutch mechanisms 30L and 30R are switched to the engaged state in response to the large required torque. That is, the brake caliper is supplied with hydraulic pressure and the hydraulic pressure is supplied to the hydraulic pressure chamber 23 by the force applied to the brake pedal BP. Braking of the wheels takes place.

On the other hand, when the detection of constant running (detection of constant running state) is confirmed in step S204, the intermittent control unit 10 instructs to release the brake pressure ON (step S206), and the constant running interlocking switching process described below is performed. transition to

FIG. 7 is a flowchart showing a constant-running-linked switching process for realizing constant-running-linked switching control.
Note that the processing shown in FIG. 6 is started in response to detection of a constant running state during 4WD running. As described above, the detection of the constant running state during 4WD running can also be performed by the transmission control unit 11 side. The processing shown in FIG. 6 is started according to the reception of the notification to be performed.

In FIG. 7, the intermittent control unit 10 performs control to put the control valve 22 in the third state (state in which only the second supply path R4 is communicated with the output path R2) (step S301). Since the brake is OFF in the constant running state, there is no need to enable the hydraulic pressure supply to the first supply path R3 side (brake caliper side). Therefore, in this example, the control valve 22 is controlled to the third state in step S301.

During 4WD running, if the brake is not in the ON state, the hydraulic pressure generation state by the hydraulic pressure adjustment unit 21 is maintained by the processing of step S202 or the like. In the constant running state, the brake is OFF (the force applied to the brake pedal BP is OFF), and when the constant running state is detected, the hydraulic pressure generation state by the hydraulic pressure adjustment unit 21 is canceled (processing of step S206, etc.). . Therefore, by setting the output path R2 and the second supply path R4 to communicate with each other in step S301, the hydraulic pressure in the hydraulic pressure chamber 23 decreases when the constant running state is detected. The clutch mechanisms 30L and 30R are switched to the non-engaged state.

The intermittent control unit 10 waits until the brake is turned ON or until the detection of the large demand torque state is confirmed in response to the above-described control to set the control valve 22 to the third state (step S302). and S303). That is, it waits until it is confirmed that the brake pedal BP is stepped on or that the required torque is equal to or greater than a predetermined value. It should be noted that it is also possible for the transmission control unit 11 to determine whether or not the condition that the value of the required torque is equal to or greater than the predetermined value is satisfied. As a result of the above determination, the transmission control unit 11 performs a process of determining whether or not notification is received when the above conditions are satisfied.

When it is confirmed that the brake is ON, the intermittent control unit 10 proceeds to step S102 in FIG. As a result, when the brake is turned on in a constant running state in 2WD, 4WD running is performed while the brake is turned on.

On the other hand, when it is confirmed in step S303 that the requested torque is large (required torque≧predetermined value), the intermittent control unit 10 proceeds to the requested torque interlocking switching process shown in FIG. That is, when a large required torque state is detected in a constant running state in 2WD, the vehicle is switched to 4WD running.

<3. Variation>
Here, in the above description, the clutch mechanisms 30L and 30R are in the engaged state in response to an increase in the brake pressure in the hydraulic pressure chamber 23. As described above, it is also possible to employ a configuration in which the clutch mechanisms 30L and 30R are brought into the engaged state in response to a decrease in the hydraulic pressure in the hydraulic pressure chamber 23. FIG.
In the following description, parts that are the same as those already explained are assigned the same reference numerals, and explanations thereof are omitted.

In the power transmission control device 1A shown in FIG. 8, an intermittent control section 10A replaces the intermittent control section 10, a hydraulic pressure adjusting section 21A replaces the hydraulic pressure adjusting section 21, and a clutch mechanism 30RA replaces the clutch mechanism 30R. It is different from the power transmission control device 1 in that a depressurization valve 25 and a depressurization passage R5 are added.
Also in this case, the illustration of the configuration for intermittent power transmission corresponding to the rear wheel 51L side is omitted. R4, pressure release valve 25, pressure release passage R5, hydraulic pressure chamber 23, piston 24, lever 34, and clutch mechanism 30LA similar to clutch mechanism 30RA are provided.

In this case, the piston 24, the tip of which abuts the one end of the lever 34, advances rightward of the vehicle 100 as the hydraulic pressure in the hydraulic pressure chamber 23 increases. In this case, the other end of the lever 34 is in contact with the front surface of the pressure plate 31 in the clutch mechanism 30RA (the surface on the same side as the frictional engagement surface with the clutch plate 32), so that the piston 24 advances in the above direction. It rotates in the clockwise direction around the rotation shaft 34a in response to the rotation.

In the clutch mechanism 30RA, a biasing member 35 is provided for the pressure plate 31, and the pressure plate 31 is biased toward the clutch plate 32 by the biasing member 35. As shown in FIG. That is, when there is no pressing force from the lever 34, the pressure plate 31 and the clutch plate 32 are engaged and the clutch mechanism 30RA is engaged. In other words, when the hydraulic pressure in the hydraulic chamber 23 increases and the pressing force of the piston 24 acts on the pressure plate 31 via the lever 34, the pressure plate 31 resists the urging force of the urging member 35 so that the pressure plate 31 becomes the clutch plate. 32, and the clutch mechanism 30RA is switched to the non-engaged state.

The depressurization valve 25 is inserted between the second supply path R4 and the hydraulic pressure chamber 23, and configured as, for example, a spool type electromagnetic valve (eg, solenoid valve).
The pressure release valve 25 has an input port 25a, a first output port 25b, and a second output port 25c, the input port 25a is connected to the second supply path R4, and the first output port 25b is connected to the hydraulic chamber 23. , and the second output port 25c is connected to the depressurization passage R5.

The depressurization valve 25 provides communication between the input port 25a and the first output port 25b, between the input port 25a and the second output port 25c, and between the first output port 25b and the second output port 25c. Non-communication is configured to be switchable. Specifically, the depressurization valve 25 is capable of switching between at least the following first state and second state as the state of communication/non-communication between these ports.
"first state"
The input port 25a and the first output port 25b and the input port 25a and the second output port 25c are disconnected, while the first output port 25b and the second output port 25c are connected. situation. That is, the second supply path R4 and the hydraulic pressure chamber 23 and the second supply path R4 and the pressure relief path R5 are not communicated with each other, while the fluid pressure chamber 23 and the pressure relief path R5 are communicated with each other.
"second state"
A state in which the input port 25a and the second output port 25c and the first output port 25b and the second output port 25c are not communicated, while the input port 25a and the first output port 25b are communicated. . That is, the second supply path R4 and the pressure relief path R5 and the pressure relief path R5 and the hydraulic pressure chamber 23 are not communicated with each other, while the second supply path R4 and the hydraulic pressure chamber 23 are communicated with each other.

The hydraulic pressure adjustment portion 21A is configured to release the hydraulic pressure input through the pressure release passage R5. Specifically, the hydraulic pressure adjustment unit 21A releases the hydraulic pressure input via the pressure relief path R5 to the above-described reservoir via a predetermined solenoid valve (hereinafter referred to as "pressure relief solenoid valve"). is configured as The hydraulic pressure adjusting section 21A of the present embodiment is configured such that the hydraulic pressure input through the pressure relief path R5 is released to the reservoir by opening the pressure relief electromagnetic valve.

The connection/disconnection control unit 10A controls the control valve 22 and the depressurization valve 25, and controls the hydraulic pressure adjustment unit 21A through the brake control unit 12, thereby switching the connection/disconnection of power transmission in the clutch mechanism 30RA (and 30LA). come true.

Processing to be executed by the intermittent control unit 10A to realize the brake interlocking switching control, the required torque interlocking switching control, and the constant running interlocking switching control will be described with reference to the flowcharts of FIGS. 9 to 11 .

FIG. 9 is a flowchart showing brake interlocking switching processing for realizing brake interlocking switching control in a modified example.
First, the intermittent control unit 10 waits until the brake is turned on (step S401), and when it is confirmed that the brake is turned on, it instructs the brake control unit 12 to release the brake pressure (step S402). ). The brake interlock switching process is started during 2WD running, and in a modified example, during 2WD running, i.e., when the clutch mechanisms 30LA and 30RA are not engaged, the hydraulic pressure adjustment unit is operated to increase the hydraulic pressure in the hydraulic pressure chamber 23. 21A uses a pump to generate brake fluid pressure. In step S402, first, an instruction to release the brake pressure ON is issued to the brake control unit 12 in order to switch from 2WD to 4WD.

Next, the intermittent control unit 10A performs control to set the control valve 22 to the second state (step S403) and control to set the depressurization valve 25 to the first state (that is, the fluid pressure chamber 23 and the depressurization passage R5 are communicated). control) is performed (step S404), and a depressurization ON instruction is given to the brake control unit 12 (step S405). In response to this depressurization ON instruction, the brake control unit 12 controls the above-described depressurization electromagnetic valve in the hydraulic pressure adjustment unit 21A to open. As a result, the hydraulic pressure in the hydraulic pressure chamber 23 is released to the reservoir in the hydraulic pressure adjustment section 21A through the pressure release passage R5. That is, the hydraulic pressure in the hydraulic pressure chamber 23 decreases, and the clutch mechanisms 30LA and 30RA are switched to the engaged state.

In response to the depressurization ON instruction, the intermittent control unit 10A waits until the brake is turned off (step S406). (step S407). This is the control of the control valve 22 for making it possible to supply the hydraulic pressure to the hydraulic pressure chamber 23 via the second supply path R4.

Next, the intermittent control unit 10A instructs the brake control unit 12 to turn on the brake pressure (step S408), and controls the depressurization valve 25 to the second state (communicating the second supply path R4 and the hydraulic pressure chamber 23). control) and returns to step S401.
When the brake is turned off by the above process, the brake fluid pressure generated by the fluid pressure adjustment unit 21A in response to the ON instruction in step S408 is supplied to the fluid pressure chamber 23 via the output path R2 and the second supply path R4. , and the hydraulic pressure in the hydraulic chamber 23 increases, thereby switching the clutch mechanisms 30LA and 30RA to the non-engagement state.

FIG. 10 is a flow chart showing a request torque interlocking switching process for realizing the request torque interlocking switching control in the modification.
First, the intermittent control unit 10A issues a brake pressure ON release instruction to the brake control unit 12 (step S501). As described above, in the modified example, during 2WD running (when the clutch mechanisms 30LA and 30RA are not engaged), the hydraulic pressure in the hydraulic pressure chamber 23 is increased by the brake hydraulic pressure generated by the hydraulic pressure adjustment section 21A. First, in step S501, the brake hydraulic pressure generation state by the hydraulic pressure adjusting section 21A is released.

Next, the intermittent control unit 10A performs control to bring the control valve 22 into the third state (step S502). It should be noted that the reason why the control valve 22 is set to the third state (the state in which only the second supply line R4 is communicated with the output line R2) in step S502 is that the required torque interlocking switching process is during acceleration and the brake is OFF. It corresponds to being

Further, the intermittent control unit 10A controls the pressure release valve 25 to be in the first state (step S503), and then instructs the brake control unit 12 to turn pressure release on (step S504). As a result, the hydraulic pressure in the hydraulic pressure chamber 23 is released to the reservoir in the hydraulic pressure adjustment portion 21A through the pressure release passage R5, the hydraulic pressure in the hydraulic pressure chamber 23 decreases, and the clutch mechanisms 30LA and 30RA enter the engaged state. can be switched.

In response to the depressurization ON instruction, the intermittent control unit 10A waits until the brake is turned ON or until constant running is detected (steps S505 and S506). The processes of steps S505 and S506 are the same as the processes of steps S203 and S204 shown in FIG.

When it is confirmed that the brake is ON, the intermittent control unit 10A proceeds to step S406 shown in FIG. That is, after switching the clutch mechanisms 30LA and 30RA to the engaged state in response to a large required torque, when the brake is turned on, the engaged state is maintained and the brake is turned off. be made to When the brakes are turned off, the processes from step S407 onward are executed, and the clutch mechanisms 30LA and 30RA are switched to the non-engagement state (that is, the vehicle is shifted to the 2WD running state).

On the other hand, when the detection of constant running is confirmed in step S506, the intermittent control unit 10A shifts to the constant running linked switching process described below.

FIG. 11 is a flowchart showing a constant-running-linked switching process for realizing constant-running-linked switching control in a modified example.
In FIG. 11, the intermittent control unit 10A performs control to put the control valve 22 in the third state (step S601), then instructs the brake control unit 12 to turn on the brake pressure (step S602), and releases the pressure. Control is performed to set the valve 25 to the second state (step S603). As a result, the hydraulic pressure in the hydraulic pressure chamber 23 increases, and the clutch mechanisms 30LA and 30RA are switched to the non-engaged state.

In response to the above-described control to put the depressurization valve 25 in the second state, the intermittent control unit 10A waits until the brake is turned ON or until it is confirmed that the required torque is large (step S604). and S605). These processes are the same as the processes of steps S302 and S303 shown in FIG.

When it is confirmed that the brake is ON, the intermittent control unit 10A proceeds to step S402 in FIG. As a result, when the brake is turned on in a constant running state in 2WD, 4WD running is performed while the brake is turned on.

On the other hand, when it is confirmed in step S605 that the high demand torque state has been detected, the intermittence control unit 10A proceeds to the demand torque interlocking switching process shown in FIG. That is, when a large required torque state is detected in a constant running state in 2WD, the vehicle is switched to 4WD running.

Here, in the above description, the clutch mechanisms 30L, 30R (30LA, 30RA) are provided for the rear wheels 51L, 51R. It can also be provided for the front wheels 51L and 51R. This makes it possible to switch between 2WD running and 4WD running by rear wheel drive.

In the above description, the vehicle 100 is a four-wheeled vehicle, but the present invention can be widely and suitably applied to vehicles having wheels. For example, for a vehicle having three rows of left and right wheel pairs in the front-rear direction, it is conceivable to provide clutch mechanisms 30L, 30R (30LA, 30RA) only for the two rear wheel pairs.

In addition, in a vehicle having at least two pairs of drive shafts in the longitudinal direction, such as the vehicle 100 of this embodiment, the clutch mechanisms 30L, 30R (30LA, 30RA) are provided for each drive shaft. can also be set to
As a result, it is possible to independently control the intermittence of power transmission for each of the wheels spaced apart in the front, rear, left, and right directions.
Therefore, it is possible to independently control each wheel spaced in the front, rear, right, and left directions as to whether or not the rotational resistance generated in the drive system of the wheels, such as engine braking, is applied to the wheels.
For example, as the running stability control of the vehicle 100, when the vehicle 100 is cornering, it is possible to realize control such as setting the disconnection mechanism on the outer wheel side to the power transmission state and setting the disconnection mechanism on the inner wheel side to the power non-transmitting state. As a result, it is possible to further improve the turning performance of the vehicle.

Further, in the above description, the clutch mechanisms 30L, 30R (30LA, 30RA) are configured to transmit power by frictional engagement. , and is not limited to a configuration in which power is transmitted by frictional engagement.

In the above description, the vehicle 100 having the engine 101 as the drive source for the wheels is illustrated, but the present invention can also be suitably applied to a vehicle that does not have the engine 101 and has a motor as the drive source for the wheels. Alternatively, the present invention can be suitably applied to a vehicle (hybrid vehicle) having both the engine 101 and the motor as drive sources for the wheels.

In the above description, the brake control system uses hydraulic pressure as brake pressure, but it is also possible to use gas pressure as brake pressure. That is, the brake pressure in the present invention is not limited to hydraulic pressure.

<4. Summary of Embodiments>
As described above, the power transmission control device (same 1 or 1A) of the embodiment transmits power from the wheels (front wheels 50L, 50R, rear wheels 51L, 51R) and the drive source (engine 101) to the wheels. A power transmission control device for a vehicle having a drive shaft (108L, 108R, etc.) and a wheel brake mechanism, wherein the intermittent mechanism (clutch mechanism 30L, 30R) is capable of intermittently interrupting power transmission from the drive shaft to the wheel. , 30LA, 30RA) and an intermittent switching mechanism (control valve 22, second supply passage R4, hydraulic pressure chamber 23, piston 24, lever 34, a depressurization valve 25, and a depressurization passage R5).

By arranging the intermittent mechanism on the output side (wheel side) of the drive shaft, the drive shaft does not rotate according to the wheel rotation when the intermittent mechanism is disconnected (power transmission is interrupted).
Therefore, it is possible to reduce friction loss, improve fuel efficiency in vehicles equipped with an engine as a drive source for wheels, and improve power consumption rate (drivable distance per unit power consumption) in vehicles equipped with a motor as a drive source. ) can be improved, and the travelable distance of the vehicle can be extended.
Also, by arranging the connecting/disconnecting mechanism on the output side of the drive shaft, the differential unit can be made smaller than the conventional example in which the connecting/disconnecting mechanism is provided in the differential unit.
Therefore, the drive shaft can be lengthened without increasing the vehicle width, the movable range of the wheels can be expanded, and the degree of freedom in designing the undercarriage of the vehicle can be improved.
Furthermore, by using the brake pressure for power intermittent switching for the wheels, the intermittent mechanism and the intermittent switching mechanism can be easily arranged at positions closer to the wheels. Since there is a brake pressure pipe for supplying brake pressure to the brake mechanism of the wheel near the wheel, the brake pressure can be supplied to the on/off switching mechanism by a branch pipe from the brake pressure pipe. The pipe length for supplying brake pressure to the switching mechanism can be shortened. In this respect, the use of brake pressure therefore has an advantage.
Further, by using the brake pressure for intermittent switching of power to the wheels, it is not necessary to add a new pressure supply source for intermittent switching.
Therefore, it is possible to reduce the number of parts and the cost for implementing intermittent switching.

In addition, in the power transmission control device (same 1) of the embodiment, the intermittent switching mechanism switches the state of the intermittent mechanism to the state in which power is transmitted when the brake pressure becomes relatively high. When the pressure becomes relatively low, the state of the intermittent mechanism is switched to the state in which power transmission is interrupted.

When the brake pressure becomes high, the connection/disconnection mechanism is brought into a state of transmitting power to the wheels, that is, the connection/disconnection mechanism is brought into a engaged state, so that it is easy to secure the connection force. Specifically, it becomes easier to secure the fastening force by increasing the pressure receiving area of the pressure receiving portion, such as a piston, which receives pressure for fastening.
In addition, when switching the intermittent mechanism to the power transmission state, it is not necessary to release the brake pressure from the intermittent switching mechanism. Therefore, additional structures such as piping and control valves necessary for releasing the brake pressure are not required, and the number of parts and costs can be reduced.

Further, in the power transmission control device (same 1A) of the embodiment, the connection/disconnection switching mechanism switches the state of the connection/disconnection mechanism to a state in which power is transmitted when the brake pressure becomes relatively low. When the pressure becomes relatively high, the state of the intermittent mechanism is switched to the state in which power transmission is interrupted.

As a result, it is possible to eliminate the need to apply brake pressure to the intermittent switching mechanism when bringing the intermittent mechanism into the power transmission state. Therefore, even when the vehicle is in a non-starting state such as when the engine of the vehicle is stopped, the connecting/disconnecting mechanism can be maintained in the power transmission state.
Therefore, in a configuration in which a set of an intermittent mechanism and an intermittent switching mechanism is provided for a plurality of wheels, when applying the parking brake to those wheels, it is possible to provide a common parking brake mechanism for each wheel on the drive source side of the intermittent mechanism. can. In other words, since there is no need to provide a parking brake mechanism for each wheel, it is possible to simplify the configuration of the hub portion that rotatably supports the wheels, reduce the number of parts, and reduce costs.

Furthermore, in the power transmission control device of the embodiment, the connecting/disconnecting mechanism is composed of a dry clutch.

This makes it possible to reduce the size of the connecting/disconnecting mechanism (compared to a wet clutch).
Since the disconnecting mechanism according to the present invention is inserted in the space between the drive shaft and the wheels, which has relatively little free space, the miniaturization of the disconnecting mechanism facilitates the design of the undercarriage of the vehicle.

Further, in the power transmission control device of the embodiment, the vehicle has at least two drive shaft pairs formed of a pair of left and right drive shafts in the front-rear direction, and the disconnecting mechanism is provided for each drive shaft.

As a result, it is possible to independently control the intermittence of power transmission for each of the wheels spaced apart in the front, rear, left, and right directions.
Therefore, it is possible to independently control each wheel spaced in the front, rear, right, and left directions as to whether or not the rotational resistance generated in the drive system of the wheels, such as engine braking, is applied to the wheels.

Reference Signs List 1, 1A power transmission control device 10, 10A intermittent control unit 11 transmission control unit 12 brake control unit 21, 21A hydraulic pressure adjustment unit 22 control valve 22a input port 22b first output port 22c second Output port 23 Hydraulic pressure chamber 24 Piston 25 Depressurization valve 25a Input port 25b First output port 25c Second output port R4 Second supply passage R5 Depressurization passage 30L, 30R, 30RA Clutch mechanism , 31 pressure plate, 32 clutch plate, 33 hub, 34 lever, 34a rotating shaft, 40 hub knuckle, 41 brake rotor, 50L, 50R front wheels, 51L, 51R rear wheels, 51Rw wheel, 100 vehicle, 106 propeller shaft, 107 Rear differential unit, 108L, 108R drive shaft

Claims (5)

A power transmission control device for a vehicle having wheels, a drive shaft for transmitting power input from a drive source through a differential mechanism to the wheels, and a brake mechanism for the wheels,
an interrupting mechanism capable of interrupting power transmission from the drive shaft to the wheel;
A power transmission control device, comprising: an intermittent switching mechanism that switches intermittence of the power transmission by the intermittent mechanism using brake pressure that operates the brake mechanism as a power source. The intermittent switching mechanism is
When the brake pressure becomes relatively high, the state of the intermittent mechanism is switched to the state in which the power is transmitted, and when the brake pressure becomes relatively low, the state of the intermittent mechanism is switched to the power transmission. 2. The power transmission control device according to claim 1, wherein the power transmission control device switches to a state in which transmission is cut off. The intermittent switching mechanism is
When the brake pressure becomes relatively low, the state of the intermittent mechanism is switched to the state in which the power is transmitted, and when the brake pressure becomes relatively high, the state of the intermittent mechanism is switched to the power transmission. 2. The power transmission control device according to claim 1, wherein the power transmission control device switches to a state in which transmission is cut off. The power transmission control device according to any one of claims 1 to 3, wherein the connecting/disconnecting mechanism comprises a dry clutch. The vehicle is
having at least two drive shaft pairs in the front-rear direction, each of which is a pair of left and right drive shafts;
The power transmission control device according to any one of claims 1 to 4, wherein the connecting/disconnecting mechanism is provided for each drive shaft.

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