JP4321809B2 - Vehicle transmission mechanism - Google Patents

Description

  The present invention relates to a transmission mechanism in a vehicle configured to transmit a driving force from a driving source to a pair of steering wheels and a pair of non-steering wheels.

  In the vehicle configured to transmit a driving force from a driving source to a pair of steered wheels and a pair of non-steered wheels respectively disposed on one side and the other side in the vehicle longitudinal direction, the pair of steered wheels It is well known in the art to connect fixed displacement hydraulic motor units corresponding to each of the two and to connect the pair of fixed displacement hydraulic motor units in parallel to a single variable displacement hydraulic pump unit (the following patents) Reference 1).

Specifically, in the vehicle of Patent Document 1, the pair of fixed displacement hydraulic motor units and the single variable displacement hydraulic pump unit are connected via a fluid (pressure oil) flowing through a flow path arranged in parallel. Power transmission is performed.
In such a vehicle, the hydraulic pump unit and the pair of hydraulic motor units can be connected by a flow path such as a pipe, so that free space can be secured without increasing the size of the vehicle, and the degree of freedom in design It has the advantage that can be improved.
In the vehicle, the fluid power (pressure oil amount) distributed and transmitted from the hydraulic pump unit to each hydraulic motor unit automatically changes according to the load applied to each of the pair of steering wheels.
That is, in the vehicle, more fluid power is transmitted to the steering wheel on the low load side than the steering wheel on the high load side of the pair of steering wheels. There is also an advantage that it is not necessary to separately provide a differential device for differentially transmitting the driving force to the pair of steering wheels.

On the other hand, the vehicle of Patent Document 1 has room for improvement in the following points.
That is, for example, when one of the pair of steered wheels becomes extremely light compared to the other, such as when one of the pair of steered wheels falls into a dent or mud. Since most of the fluid power transmitted from the hydraulic pump unit is distributed to the steering wheel on the low load side, the vehicle cannot be run normally.
Japanese Utility Model Publication No. 54-63330

The present invention has been made in view of the prior art, and transmits a driving force from a driving source to a pair of steering wheels and a pair of non-steering wheels disposed on one side and the other side in the vehicle longitudinal direction. In the transmission mechanism of the vehicle configured to obtain, a free space can be effectively secured in the transmission mechanism from the drive source to the pair of steered wheels, the differential device can be eliminated, and the pair of An object of the present invention is to provide a transmission mechanism having a simple structure capable of forcibly driving both of a pair of steering wheels when one of the steering wheels enters a depression or a swamp.
Further, the present invention provides a vehicle transmission configured to transmit a driving force from a driving source to a pair of steered wheels and a pair of non-steered wheels disposed on one side and the other side of the vehicle longitudinal direction. This mechanism can effectively secure free space in the transmission mechanism from the drive source to the pair of steered wheels, eliminate the need for a differential device, and force both the pair of steered wheels depending on the situation. Another object of the present invention is to provide a transmission mechanism with a simple structure that can be driven at the same time, and that can also prevent excessive high-speed turning while preventing dragging of the steering wheel during turning of the vehicle.

In order to achieve the above-mentioned object, the present invention can transmit a driving force from a driving source to a pair of steered wheels and a pair of non-steered wheels respectively disposed on one side and the other side of the vehicle longitudinal direction. A vehicle transmission mechanism configured as described above, wherein a hydraulic pump unit operatively connected to the drive source, and first and second hydraulic pressures each having a motor shaft operatively connected to one and the other of the pair of steering wheels. A motor unit, a first and a second hydraulic motor unit that are fluidly connected to the hydraulic pump unit in a parallel state, and a steering wheel that houses both the first and second hydraulic motor units so that they face each other. A transmission mechanism is provided that includes a drive axle case and a clutch device housed in the steered wheel drive axle case so as to be positioned between the first and second hydraulic motor units.
At least one of the hydraulic pump unit and the first and second hydraulic motor units is a variable displacement type in which the suction / discharge amount changes depending on the tilt position of the output adjustment member.
The clutch device includes a clutch release state in which the motor shafts of the first and second hydraulic motor units are relatively rotatable about an axis, and a clutch engagement state in which the motor shafts are connected so as not to be relatively rotatable about the axis. being configured to be taken, the difference between the load applied to the pair of steering wheels that are the configured limited slip type to take automatically the clutch engagement exceeds a predetermined range.

In one aspect, the hydraulic pump unit is a variable displacement type, and the first and second hydraulic motor units are a fixed displacement type.
In another aspect, the hydraulic pump unit is a fixed displacement type, and the first and second hydraulic motor units are a variable displacement type.
In the various aspects, a reduction gear mechanism may be provided between each motor shaft of the first and second hydraulic motor units and the corresponding steering wheel.

Preferably, the transmission mechanism according to the various aspects further includes a vehicle state detection device that detects whether the vehicle is in a straight traveling state or a turning state, and a non-steering wheel drive that detects a driving speed of the pair of non-steering wheels. A speed detection device, an output adjustment member actuating device that tilts the output adjustment member, and a control device that controls the operation of the output adjustment member actuating device can be provided.
Based on signals from the vehicle state detection device and the non-steering wheel drive speed detection device, the control device is configured such that when the vehicle is in a straight traveling state, the pair of steering wheels is When the output adjustment member is tilted to the reference position by the output adjustment member actuating device so as to rotate at a reference drive speed of 1 to 1.05 times, and the vehicle is shifted from the straight traveling state to the turning state. Is configured such that the output adjusting member is tilted from the reference position by the output adjusting member actuating device so that the driving speed of the pair of steered wheels is higher than the reference driving speed.

  In the preferred aspect, more preferably, a steered wheel speed detecting device for detecting a driving speed of the pair of steered wheels is further provided, and the control device adjusts the output by a signal from the steered wheel speed detecting device. The member actuator may be configured to feedback control.

In order to achieve the above object, the present invention can transmit a driving force from a driving source to a pair of steered wheels and a pair of non-steered wheels respectively disposed on one side and the other side of the vehicle longitudinal direction. A steered wheel hydraulic pump unit that is operatively connected to the drive source, and each motor shaft is operatively connected to one and the other of the pair of steered wheels. First and second steering wheel hydraulic motor units, wherein the first and second steering wheel hydraulic motor units are fluidly connected to the steering wheel hydraulic pump unit in parallel; The steering wheel drive axle case that houses the second steering wheel hydraulic motor unit so as to face each other, and the first and second steering wheel hydraulic motor units are positioned between the steering wheel driving axle case and the steering wheel driving axle case. Clutch housed in a wheel drive axle case A non-steering wheel hydraulic pump unit operatively connected to the drive source, and a non-steering wheel hydraulic motor unit whose motor shaft is operatively connected to the pair of non-steering wheels, Provided is a transmission mechanism including a steered wheel hydraulic pump unit and a non-steered wheel hydraulic motor unit fluidly connected.
At least one of the steered wheel hydraulic pump unit and the first and second steered wheel hydraulic motor units has a variable displacement type in which a suction / discharge amount varies depending on a tilt position of the steered wheel output adjusting member. It is said.
At least one of the non-steering wheel hydraulic pump unit and the non-steering wheel hydraulic motor unit is a variable displacement type in which the suction / discharge amount changes depending on the tilt position of the non-steering wheel output adjusting member. The
The clutch device includes a clutch release state in which the motor shafts of the first and second steering wheel hydraulic motor units are relatively rotatable about an axis, and a clutch mechanism for connecting the motor shafts so as not to be relatively rotatable about the axis. It is configured to be able to take a combined state.
Further, the transmission mechanism includes a vehicle state detection device that detects whether the vehicle is in a straight traveling state or a turning state, a first operating device that tilts the steering wheel output adjusting member, and the non-steering wheel output adjustment. A second actuator that tilts the member; a controller that controls the operation of the first and second actuators; and the hydraulic motor unit for the non-steering wheel and the non-steering wheel. A multi-stage transmission comprising a multi-stage transmission having a plurality of shift stages including a high-speed stage engaged when the vehicle is in a high-speed traveling state, and a shift stage detection apparatus for detecting a shift stage of the multi-stage transmission. .
The control device operates the second actuator so as to tilt the non-steered wheel output adjusting member according to an operation amount of a speed operation member operated by a driver.
Further, the control device is configured such that when the vehicle is in a straight traveling state, the pair of steered wheels is 1 to 1.05 times the pair of non-steered wheels based on a signal from the vehicle state detection device. When the first actuating device is operated so as to be rotationally driven at the reference driving speed and the vehicle is shifted from the straight traveling state to the turning state, the driving speed of the pair of steering wheels and the pair of steering wheels are The first actuating device and / or the second actuating device is actuated so that the speed difference from the non-steering wheel driving speed increases. The control device is further configured to be able to determine whether or not the vehicle is in a high speed traveling state based on a signal from the gear position detecting device, and the vehicle is shifted from a straight traveling state to a turning state while remaining in the high speed traveling state. Then, the non-steering wheel output adjustment is performed by the second actuator so that the driving speed of the non-steering wheel is reduced while maintaining the tilt position of the steering wheel output adjusting member. Tilt the member.

Good Mashiku, the control device, based on a signal from the gear position detecting apparatus, when the vehicle is shifted from the straight state when the low-speed or medium-speed running state other than the high-speed running state to the turning state, the non The steering wheel output adjusting member can be tilted by the first actuating device so that the driving speed of the steering wheel is increased while maintaining the tilting position of the steering wheel output adjusting member. .

According to one aspect of the present invention , a free space can be effectively secured in the transmission mechanism from the drive source to the pair of steering wheels, and the degree of design freedom can be improved. Further, the driving force from the driving source separately there is no need to provide a differential device for the differential transmission to a pair of steering wheels, it is possible to cost reduction in cost. Further, the clutch release state in which each motor shaft of the first and second hydraulic motor units operatively connected to one and the other of the pair of steering wheels is relatively rotatable about the axis, or both the motor shafts are relatively rotated about the axis. A clutch device that can be engaged in a clutch engaged state, and is configured to automatically take the clutch engaged state when a difference in load applied to the pair of steering wheels exceeds a predetermined range. Since a slip-type clutch device is provided, when one of the pair of steered wheels enters a depression or swamp , the driving force can be forcibly transmitted to both of the pair of steered wheels. Therefore, the transmission state suitable for various traveling states can be obtained effectively. Furthermore, the said clutch device for being arranged between the first and second hydraulic motor unit can effectively prevent the upsizing by having the clutch device.

According to another aspect of the present invention, a steered wheel hydraulic pump unit, first and second steered wheel hydraulic motor units operatively connected to one and the other of a pair of steered wheels, A clutch device capable of taking a clutch disengaged state in which each motor shaft of the second steered wheel hydraulic motor unit is relatively rotatable about an axis or a clutch engaged state in which the both motor shafts are connected so as not to be relatively rotatable about an axis; Steering wheel hydraulic pump unit, non-steering wheel hydraulic motor unit whose motor shaft is operatively connected to the pair of non-steering wheels, and a vehicle state detection device for detecting whether the vehicle is in a straight traveling state or a turning state A first actuating device for tilting a steered wheel output adjusting member that changes a suction / discharge amount of at least one of the steered wheel hydraulic pump unit and the first and second steered wheel hydraulic motor units. And said non-operation A second actuating device for tilting a non-steered wheel output adjusting member that changes a suction / discharge amount of at least one of the wheel hydraulic pump unit and the non-steered wheel hydraulic motor unit; A control device that controls the operation of the two actuators, a multi-stage transmission that is disposed between the non-steering wheel hydraulic motor unit and the non-steering wheel, and a shift that detects a shift stage of the multi-stage transmission A step detection device, and when the control device determines that the vehicle is in a high-speed traveling state based on a signal from the gear position detection device, the steering wheel moves when the vehicle moves from a straight traveling state to a turning state. The second adjusting device tilts the non-steering wheel output adjusting member so that the driving speed of the non-steering wheel is reduced while maintaining the tilting position of the output adjusting member. A pair of controls from the drive source. It is possible unnecessary the effectively ensured can and differential free space in the transmission mechanism leading to wheels, it is possible to forcibly drive both of the pair of steerable wheels according to the situation, further, when the vehicle turning It is possible to prevent excessive high-speed turning while preventing the steering wheel from being dragged.

Hereinafter, a transmission mechanism according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a transmission schematic diagram of a vehicle to which a transmission mechanism 1 according to the present embodiment is applied.

The transmission mechanism 1 is configured to be able to transmit the driving force from the driving source 100 to a pair of steering wheels and a pair of non-steering wheels disposed on one side and the other side in the vehicle longitudinal direction.
In the present embodiment, the front wheel 110 is a steered wheel, and the rear wheel 120 is a non-steered wheel.

  As shown in FIG. 1, the transmission mechanism 1 according to the present embodiment includes a pair of steering wheels (in the present embodiment, front wheels) disposed on one side in the vehicle longitudinal direction. 110) and a pair of non-steering wheels (rear wheels 120 in the present embodiment) disposed on the other side in the vehicle direction. And a non-steering wheel transmission mechanism 300 configured to be able to.

  The steered wheel transmission mechanism 200 includes a hydraulic pump unit 10 operatively connected to the drive source 100, first and second hydraulic motor units 20 and 30 respectively corresponding to the pair of steered wheels 110, and the first The steered wheel drive axle case 40 accommodating the first and second hydraulic motor units 20 and 30 and the steered wheel drive axle case 40 so as to be positioned between the first and second hydraulic motor units 20 and 30. And a clutch device 50 housed in the housing.

The first and second hydraulic motor units 20 and 30 are fluidly connected to the hydraulic pump unit 10 in a parallel relationship.
That is, one of the pair of suction / discharge ports 10a and 10b in the hydraulic pump unit 10 is connected to one of the pair of suction / discharge ports 20a and 20b in the first hydraulic motor unit 20 and the second hydraulic motor unit 30. And the other 10b of the pair of suction / discharge ports 10a, 10b in the hydraulic pump unit 10 is a pair in the first hydraulic motor unit 20. And the other 20 b of the suction / discharge ports 20 a, 20 b and the other 30 b of the pair of suction / discharge ports 30 a, 30 b in the second hydraulic motor unit 30.

Further, at least one of the hydraulic pump unit 10 and the first and second hydraulic motor units 20 and 30 is a variable displacement type.
In the present embodiment, as shown in FIG. 1, the hydraulic pump unit 10 is a variable displacement type, and the first and second hydraulic motor units 20, 30 are a fixed displacement type.
Specifically, the hydraulic pump unit 10 has an output adjustment member 11 such as a swash plate, and the suction / discharge amount (and suction / discharge direction) is changed depending on the tilt position of the output adjustment member 11. Yes.

The hydraulic pump unit 10 is configured to transmit the rotational power input from the driving source 100 to the first and second hydraulic motor units 20 and 30 that are in parallel with each other via a fluid. Yes.
A method for controlling the output adjusting member 11 will be described later.

The first and second hydraulic motor units 20 and 30 have motor shafts 21 and 31 that are operatively connected to corresponding steering wheels 110, respectively.
Specifically, the first hydraulic motor unit 20 includes a first hydraulic motor main body (not shown) fluidly connected to the hydraulic pump unit 10 and a first motor case (not shown) surrounding the first hydraulic motor main body. And the first motor shaft 21 extending in the vehicle width direction so that both end portions protrude outward from the first motor case.
Similarly, the second hydraulic motor unit 30 includes a second hydraulic motor main body (not shown) fluidly connected to the hydraulic pump unit 10 and a second motor case (not shown) surrounding the second hydraulic motor main body. And a second motor shaft 31 extending in the vehicle width direction so that both end portions protrude outward from the second motor case.

Preferably, the first and second motor shafts 21 and 31 are disposed concentrically.
In the present embodiment, as shown in FIG. 1, each of the first and second motor shafts 21 and 31 has a reduction mechanism between the outer end portions and the corresponding steered wheels 110, respectively. A functioning planetary gear unit 95 is provided.

  The clutch device 50 includes a clutch disengaged state in which the first motor shaft 21 of the first hydraulic motor unit 20 and the second motor shaft 31 of the second hydraulic motor unit 30 are relatively rotatable about an axis, and both the motor shafts 21. , 31 can be engaged with a clutch engaged state in which relative rotation about the axis is impossible.

In the present embodiment, the clutch device 50 is a hydraulic clutch that can selectively take a clutch released state and a clutch engaged state by the action of hydraulic pressure.
In such a hydraulic clutch, the clutch release state and the clutch engagement state can be selectively obtained by supplying / shut off the pressure oil based on an external operation by the driver.

  In the present embodiment, the clutch device 50 is configured to switch between the clutch disengaged state and the clutch engaged state based on an external operation by the driver. It is also possible to adopt a limited slip type in which the clutch is automatically switched from the released state to the engaged state when the difference in load applied to the facing wheel 110 exceeds a predetermined range.

Thus, in the transmission mechanism 1 according to the present embodiment, the steered wheel transmission mechanism 200 is configured by the hydraulic pump unit 10 and the first and second hydraulic motor units 20 and 30. Therefore, the free space can be effectively secured as compared with the mechanical transmission mechanism.
Further, since the first and second hydraulic motor units 20 and 30 are fluidly connected to the hydraulic pump unit 10 in a parallel relationship, a driving source is not provided without a differential device such as a differential gear device. Power can be differentially transmitted from 100 to a pair of steering wheels 110.
Further, in the present embodiment, the clutch engagement state in which the motor shafts 21 and 31 of the first and second hydraulic motor units 20 and 30 are connected so as not to be relatively rotatable, and the motor shafts are relatively rotatable. The clutch device 50 capable of selectively taking the clutch engaged state is provided.
According to such a configuration, when one of the pair of steered wheels 110 enters a depression or swamp, power can be forcibly transmitted to the other steered wheel.
Therefore, an optimal transmission state can be obtained according to various traveling environments.

In the present embodiment, as described above, the differential device for the pair of steering wheels 110 can be eliminated.
Accordingly, the clutch device 50 can be disposed between the first and second hydraulic motor units 20 and 30, and the steering wheel drive axle case 40 accommodating them can be prevented from being enlarged.

Next, a method for controlling the output adjusting member 11 (hereinafter referred to as a steering wheel output adjusting member) in the steered wheel transmission mechanism 200 will be described.
The steering wheel output adjusting member 11 is controlled based on the driving speed of the non-steering wheel 120 by the non-steering wheel transmission mechanism 300 and the traveling state of the vehicle.

  Specifically, in addition to the above-described configuration, the transmission mechanism 1 according to the present embodiment includes a vehicle state detection device 60 that detects whether the vehicle is in a straight traveling state or a turning state, and the driving speeds of the pair of non-steering wheels 120. A non-steering wheel drive speed detection device 65 for detecting, a first operating device 70 for tilting the steering wheel output adjusting member 11, and a control device 75 for controlling the operation of the first operating device 70 are provided. Yes.

The vehicle state detection device 60 is, for example, a sensor that detects a steering amount of a steering member 150 such as a steering that swings the pair of steering wheels 110 or a sensor that detects a swing angle of the pair of steering wheels 110. Or it can be set as the sensor etc. which detect the displacement amount of the movable member in a power steering device.
In the illustrated embodiment, a sensor that detects the steering amount of the steering member 150 is used as the vehicle state detection device 60.

The non-steered wheel drive speed detection device 65 includes, for example, a sensor that detects an operation amount of a speed operation member 160 such as a travel pedal, and a non-steered wheel drive axle 130 that is operatively connected to the pair of non-steered wheels 120. A rotational speed sensor for detecting the rotational speed of
In the illustrated embodiment, a sensor that detects the rotational speed of the non-steered wheel drive axle 130 is used as the non-steered wheel drive speed detector 65.

The control device 75 is configured to operate the first operation device 70 based on signals from the vehicle state detection device 60 and the non-steering wheel drive speed detection device 65.
Specifically, when the control device 75 determines that the vehicle is in a straight traveling state based on a signal from the vehicle state detection device 60, the pair of steered wheels 110 causes the non-steered wheel drive speed to move. The first actuating device 70 is operated so as to rotate at a reference driving speed of 1 to 1.05 times the driving speed of the non-steering wheel based on the signal from the detection device 65.
On the other hand, when the control device 75 determines that the vehicle is turning based on the signal from the vehicle state detection device 60, the drive speed of the pair of steering wheels 110 is higher than the reference drive speed. The first operating device 70 is operated so as to increase the speed (for example, 1 to 2 times the non-steering wheel driving speed).

That is, the control device 75 drives the pair of steered wheels 110 at the reference drive speed when the vehicle is in a straight traveling state, and moves the pair of steered wheels 110 when the vehicle is turning. The vehicle is driven at a speed higher than the reference driving speed, and this can prevent problems caused by a difference in turning radius between the pair of steered wheels 110 and the pair of non-steered wheels 120 when the vehicle turns. It is like that.
Note that the rate of acceleration of the pair of steered wheels 110 when the vehicle is turning can be controlled according to the turning radius of the vehicle.

  More preferably, the transmission mechanism 1 further includes a steering wheel speed detection device 80 that detects a driving speed of the pair of steering wheels 110, and the control device 75 controls the steering wheel speed detection device 80. The first actuator 70 can be feedback-controlled by a signal from

Hereinafter, the non-steering wheel transmission mechanism 300 will be described.
The non-steering wheel transmission mechanism 300 is configured to drive the pair of non-steering wheels 120 at a driving speed based on the operation amount of the speed operation member 160.
In the present embodiment, the non-steering wheel transmission mechanism 300 includes a non-steering wheel hydraulic pump unit 310 that is operatively driven by the drive source 100, and a fluid connection with the non-steering wheel hydraulic pump unit 310. The non-steering wheel hydraulic motor unit 320 is provided.

At least one of the non-steering wheel hydraulic pump unit 310 and the non-steering wheel hydraulic motor unit 320 has an output adjusting member 311 (hereinafter referred to as an “non-steering wheel output adjusting member”). The variable volume type in which the suction / discharge amount (and suction / discharge direction) changes depending on the tilt position of the output adjusting member 311 for use.
In this embodiment, as shown in FIG. 1, the non-steering wheel hydraulic pump unit 310 is a variable displacement type, and the non-steering wheel hydraulic motor unit 320 is a fixed displacement type.

The non-steering wheel output adjustment member 311 tilts in conjunction with the operation of the speed operation member 160.
Specifically, in addition to the above configuration, the transmission mechanism 1 according to the present embodiment includes a speed operation detection device 85 that detects an operation amount of the speed operation member 160 and the output adjustment member 311 for non-steering wheels. And a second actuating device 90 for tilting.
The speed operation detection device 85 transmits a signal indicating the operation amount of the speed operation member 160 to the control device 75.
Then, the control device 75 operates the second operation device 90 based on the signal from the speed operation detection device 85, and operates the non-steered wheel output adjustment member 311 with the operation amount of the speed operation member 160. It is designed to be positioned at a tilt position according to the above.

Thus, in the present embodiment, the control device 75 not only controls the tilt position of the steering wheel output adjustment member 11 but also tilts the non-steering wheel output adjustment member 311. The position is also controlled.
In such an embodiment, it is preferable that two modes of transmission control in the vehicle turning state can be prepared according to the vehicle traveling speed.

That is, when the vehicle is turned in a state where the vehicle is traveling straight at a medium speed or less (hereinafter referred to as a medium / low speed state), the control device 75 performs the control as described above.
That is, the control device 75 causes the first steering device 70 to drive the steering wheel so that the pair of steering wheels 110 are driven at a speed higher than the reference driving speed when turning in a medium / low speed state. The output adjusting member 11 is tilted.
Such a medium / low speed control mode is shown in FIGS.
FIG. 2 shows changes in the driving speed of the steered wheel 110 and the non-steered wheel 120 with respect to the manipulated variable of the speed manipulating member 160 divided into a vehicle straight traveling state and a vehicle turning state.
FIG. 3 shows the steering wheel 110 and the non-steering when the steering member 150 is operated while the speed operation member 160 is fixed at a predetermined position in the medium / low speed state (constant speed traveling state). The change of the driving speed of the wheel 120 is shown.
As shown in FIG. 3, the rate at which the steered wheel 110 is accelerated can be proportional to the steering amount of the steering member 150.

On the other hand, when the vehicle is turned in a state where the vehicle is traveling straight ahead at a high speed (hereinafter referred to as a high speed state), the control device 75 maintains the tilt position of the steering wheel output adjusting member 11. In this state, the non-steering wheel output adjusting member 311 can be controlled to tilt so that the driving speed of the non-steering wheel 120 is reduced.
Such a high-speed control mode is shown in FIG.
FIG. 4 shows a change in driving speed of the steered wheel 110 and the non-steered wheel 120 when the steering member 150 is operated while the speed operation member 160 is fixed at a predetermined position in the high speed state. Is shown.
As shown in FIG. 4, when the vehicle is turned when the vehicle is traveling straight at a high speed, the control device 75 maintains the driving speed of the pair of steering wheels 110 as it is, and the first device The two actuators 90 may be configured to decelerate the driving speed of the pair of non-steering wheels 120 from the reference driving speed.

Even in such a high-speed control mode, a difference in driving speed between the pair of steered wheels 110 and the pair of non-steered wheels 120 can be ensured when the vehicle turns.
Accordingly, it is possible to effectively prevent inconveniences such as dragging of the pair of steering wheels 110 when the vehicle turns.
Further, in the high-speed control mode, instead of increasing the drive speed of the pair of steered wheels 110, the drive speed of the pair of non-steer wheels 120 is decelerated, so Since the relative speed difference between the steered wheels 120 is ensured, the vehicle posture can be stabilized when turning at high speed.

Note that the determination of whether the vehicle is in a medium or low speed state or a high speed state can be made based on the traveling speed of the vehicle, but the following configuration is adopted in the present embodiment.
That is, the transmission mechanism 1 according to the present embodiment is disposed between the non-steering wheel hydraulic motor unit 320 and the non-steering wheel 120 in addition to the above-described configuration, as shown in FIG. The multi-stage transmission 350 and a shift stage detection device 355 for detecting the shift stage of the multi-stage transmission 350 are provided.
The multi-stage transmission 350 has a plurality of shift stages including a high-speed stage 350H that is engaged when the vehicle is in a high-speed traveling state.
In the present embodiment, the multi-stage transmission 350 has a medium speed stage 350M and a low speed stage 350L in addition to the high speed stage 350H.

In a vehicle equipped with the multi-stage transmission 350, the multi-stage transmission 350 is engaged with the medium speed stage 350M or the low speed stage 350L when the vehicle is in a working state, and when traveling on a paved road or the like. Is engaged with the high speed stage 350H.
Accordingly, the control device 75 determines that the multi-stage transmission device 350 is in the high speed state when the multi-stage transmission device 350 is engaged with the high speed stage 350H based on the signal from the gear stage detection device 355, and the multi-stage gear stage. When the transmission 350 is engaged with a speed stage other than the high speed stage (in the illustrated form, the medium speed stage 350M or the low speed stage 350L), it can be determined that the vehicle is in the medium / low speed state.

FIG. 1 is a transmission schematic diagram of a vehicle to which a transmission mechanism according to an embodiment of the present invention is applied. FIG. 2 is a graph showing the “change ratio of the driving speed of the steered wheels and non-steered wheels with respect to the operation amount of the speed operation member” in the vehicle shown in FIG. 1 separately for the vehicle straight traveling state and the vehicle turning state. . FIG. 3 is a graph showing “change rate of driving speed of steered wheels and non-steered wheels with respect to the operation amount of the steering member” when the vehicle shown in FIG. 1 is traveling at a constant speed in a medium / low speed state. FIG. 4 is a graph showing “change rate of driving speed of steered wheels and non-steered wheels with respect to an operation amount of a steering member” when the vehicle shown in FIG. 1 is traveling at a constant speed in a high speed state.

DESCRIPTION OF SYMBOLS 1 Transmission mechanism 10 Steering wheel hydraulic pump unit 11 Steering wheel output adjustment member 20 Steering wheel first hydraulic motor unit 30 Steering wheel second hydraulic motor unit 40 Steering wheel drive axle case 50 Clutch device 60 Vehicle state detection device 65 Non-steering wheel drive speed detection device 70 Steering wheel output adjusting member actuating device 75 Controller 80 Steering wheel driving speed detecting device 90 Non-steering wheel output adjusting member actuating device 95 Reduction gear Mechanism 310 Non-steering wheel hydraulic pump unit 311 Non-steering wheel output adjusting member 320 Non-steering wheel hydraulic motor unit 350 Multi-stage transmission 355 Shift stage detection apparatus

Claims (3)

A vehicle transmission mechanism configured to transmit a driving force from a driving source to a pair of steered wheels and a pair of non-steered wheels respectively disposed on one side and the other side of the vehicle longitudinal direction,
A hydraulic pump unit operatively connected to the drive source;
First and second hydraulic motor units each having a motor shaft operatively connected to one and the other of the pair of steering wheels, wherein the first and second hydraulic fluid units are fluidly connected to the hydraulic pump unit in a parallel state. A motor unit;
A steered wheel drive axle case that houses the first and second hydraulic motor units so that they face each other;
A clutch device housed in the steered wheel drive axle case so as to be positioned between the first and second hydraulic motor units;
At least one of the hydraulic pump unit and the first and second hydraulic motor units is a variable displacement type in which the suction / discharge amount changes depending on the tilt position of the output adjustment member,
The clutch device includes a clutch release state in which the motor shafts of the first and second hydraulic motor units are relatively rotatable about an axis, and a clutch engagement state in which the motor shafts are connected so as not to be relatively rotatable about the axis. The limited slip type is configured to automatically take the clutch engaged state when a difference in load applied to the pair of steering wheels exceeds a predetermined range. Characteristic vehicle transmission mechanism. A vehicle transmission mechanism configured to transmit a driving force from a driving source to a pair of steered wheels and a pair of non-steered wheels respectively disposed on one side and the other side of the vehicle longitudinal direction,
A steering wheel hydraulic pump unit operatively connected to the drive source;
A hydraulic motor unit for first and second steering wheels, each motor shaft being operatively connected to one and the other of the pair of steering wheels, and fluidly connected to the steering wheel hydraulic pump unit in parallel. Hydraulic motor units for the first and second steering wheels,
A steered wheel drive axle case that houses the first and second steered wheel hydraulic motor units so that they face each other;
A clutch device housed in the steered wheel drive axle case so as to be positioned between the first and second steered wheel hydraulic motor units;
A non-steering wheel hydraulic pump unit operatively connected to the drive source;
A non-steering wheel hydraulic motor unit operatively coupled to the pair of non-steering wheels, the non-steering wheel hydraulic motor unit fluidly connected to the non-steering wheel hydraulic pump unit; With
At least one of the steered wheel hydraulic pump unit and the first and second steered wheel hydraulic motor units has a variable displacement type in which a suction / discharge amount varies depending on a tilt position of the steered wheel output adjusting member. And
At least one of the non-steering wheel hydraulic pump unit and the non-steering wheel hydraulic motor unit is a variable displacement type in which the suction / discharge amount changes depending on the tilt position of the non-steering wheel output adjusting member. And
The clutch device includes a clutch release state in which the motor shafts of the first and second steering wheel hydraulic motor units are relatively rotatable about an axis, and a clutch mechanism for connecting the motor shafts so as not to be relatively rotatable about the axis. It is configured to be able to take a combined state,
The transmission mechanism further includes:
A vehicle state detection device for detecting whether the vehicle is traveling straight or turning,
A first actuator for tilting the steering wheel output adjusting member;
A second actuating device for tilting the non-steering wheel output adjusting member;
A control device for operating the first and second actuators ;
A multi-stage transmission device disposed between the non-steering wheel hydraulic motor unit and the non-steering wheel, wherein a plurality of shift stages including a high-speed stage that is engaged when the vehicle is in a high-speed traveling state. A multi-stage transmission having
A shift speed detection device for detecting a shift speed of the multi-speed transmission ,
The control device operates the second operating device to tilt the non-steered wheel output adjusting member according to an operation amount of a speed operating member operated by a driver, and the vehicle state detecting device Based on the signal from the vehicle, when the vehicle is traveling straight, the pair of steered wheels are rotationally driven at a reference drive speed of 1 to 1.05 times the pair of non-steered wheels When the first actuating device is operated and the vehicle is shifted from the straight traveling state to the turning state, the speed difference between the driving speed of the pair of steering wheels and the driving speed of the pair of non-steering wheels Actuating the first actuator and / or the second actuator so that
The control device is further configured to be able to determine whether or not the vehicle is in a high speed traveling state based on a signal from the gear position detecting device, and the vehicle is shifted from a straight traveling state to a turning state while remaining in the high speed traveling state. Then, the non-steering wheel output adjustment is performed by the second actuator so that the driving speed of the non-steering wheel is reduced while maintaining the tilt position of the steering wheel output adjusting member. vehicle transmission mechanism, characterized in Rukoto is tilting the member. Based on the signal from the gear position detection device, the control device outputs the non-steered wheel output when the vehicle is shifted from a straight traveling state to a turning state when the vehicle is in a low speed or medium speed traveling state other than the high speed traveling state. while maintaining the tilt position of the adjustment member, wherein, characterized in that tilting the steering wheel output adjusting member by said first actuator such that the driving speed of the steering wheel is accelerated Item 3. The vehicle transmission mechanism according to Item 2 .

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