JPH0624887B2 - Axle device for four-wheel drive vehicle - Google Patents

Description

The present invention relates to an axle device for an automobile having a function of switching between four-wheel drive and two-wheel drive.

(Prior Art) In a so-called part-time four-wheel drive vehicle that can temporarily switch from two-wheel drive (2WD) to four-wheel drive (4WD), the rotation of the input shaft to which the engine output is transmitted is
A two-wheel / four-wheel switching mechanism having a pair of output shafts for transmitting to a wheel-to-wheel differential device provided between each of the front and rear wheels and having a hub clutch is provided in the transfer device. I have it.

By the way, in the axle device of this type of vehicle, when two wheels are driven, the ring gear of the inter-wheel differential device provided between the wheels on the idle wheel side is driven by the rotation of the wheels (back drive).
Then, the oil is agitated by the ring gear and driven up to the propeller shaft, resulting in a large mechanical loss. Therefore, in order to reduce the occurrence of such mechanical loss, a so-called free wheel structure in which a clutch for interrupting this transmission is provided on the left and right axle shafts between the wheels on the idler wheels at the time of driving the two wheels described above. It has been known.

In addition, since using two clutches in this way is disadvantageous in terms of cost and space, the clutch is installed only on one of the left and right axle shafts.
Individual pieces are also known (for example, JP-A-56-1).
35320). In this configuration, with respect to the back drive by the idle wheel during two-wheel drive, the side gear of the differential device connected to the axle shaft on the side where the clutch is not installed is back-driven, while the clutch is installed. The side gear connected to the axle shaft on the open side is not back-driven because the clutch is disengaged. Since the torque load is removed from the latter side gear, the former side gear only reversely rotates the latter side gear via the pinion gear and does not rotationally drive the ring gear or the propeller shaft. Therefore, the occurrence of a large mechanical loss can be suppressed.

By the way, in the above-mentioned structure, in the idle wheel during two-wheel drive, the drive side wheel of the clutch is driven through the differential device by the rotation of one wheel as described above, and is rotated in the direction opposite to the rotation direction of the wheel. On the other hand, the driven wheel of the clutch to which the rotation of the other wheel is transmitted is rotated in the rotation direction of this wheel. That is, the drive side wheel and the sub drive wheel of the clutch, which are opposed to each other, are rotated in opposite directions. However,
When switching from two-wheel drive (2WD) to four-wheel drive (4WD), the clutch is engaged, but as described above, the opposite wheels of the clutch rotate in opposite directions and the relative speed becomes extremely high. For this reason, it is difficult to connect the clutch as it is, and it is necessary to carry out the operation after the vehicle is stopped, or a large-scale synchronizing device is required. As a result, there has been a problem that the switching operation to the four-wheel drive becomes inconvenient or the cost becomes high.

(Object of the Invention) The present invention solves the above-mentioned problems of the prior art by using a differential lock mechanism provided in a differential device at the time of switching from two-wheel drive to four-wheel drive. It is an object of the present invention to provide an axle device for a four-wheel drive vehicle that does not require the structure, has a simple structure, and can synchronize easily for clutch connection.

(Structure of the Invention) The present invention provides a transfer device having a pair of output shafts for transmitting the rotation of an input shaft to a wheel-to-wheel differential device provided between front and rear wheels. 4 with mechanism
In an axle device of a wheel drive vehicle, a clutch that cuts off this transmission path is provided on one of the axle shafts to which output is transmitted from the output gear of the wheel-to-wheel differential device on the wheel side that is an idle wheel when driving two wheels. The differential device is provided with a differential lock mechanism, and the differential lock mechanism is operated when the clutch is connected based on a switching command from the two-wheel drive to the four-wheel drive, and the driven side of the clutch and the output gear. It is provided with a differential lock control device for synchronizing the connection side.

With this configuration, when the two-wheel drive is switched to the four-wheel drive, the differential lock mechanism of the differential gear is turned on prior to the clutch connection operation, so that the clutch can be synchronized and the connection can be easily performed. is there.

(Embodiment) FIG. 1 and FIG. 2 show an embodiment of the present invention, in which a transfer device having a two-wheel / four-wheel switching mechanism with a hub clutch built in behind a transmission 1 as an engine output transmission mechanism. The transfer device 2 has a pair of output shafts for transmitting the rotation of its input shaft to inter-wheel differential devices 9 provided between the front and rear wheels, respectively, as will be described later. Propeller shaft 3, 4 on output shaft
Are connected.

The front wheels 5 and 6 are attached to the axle shafts 7 and 8 via a wheel hub (the same applies to the rear wheels (not shown), and an inter-wheel differential device 9 is provided between the front wheels 5 and 6 and between the rear wheels. . Further, in the present embodiment, the front wheels 5 and 6 become idle wheels during two-wheel drive, and one of the axles to which the output is transmitted from the output gear (side gear 19 described later) of the inter-wheel differential device 9 on the front wheel side that becomes the idle wheels. The shaft 8 is provided with a clutch 10 that disconnects this transmission path.

In the inter-wheel differential device 9, the drive pinion gear 12 provided at the tip of the drive shaft 11 to which the output is transmitted from the propeller shaft 4, the ring gear 13 meshed with the drive pinion gear 12, and the ring gear 13 are integrally provided. Differential case (differential case)
14, a pinion shaft 15 whose both ends are fixed to the differential case 14, pinion gears 16 and 17 rotatably fitted to the pinion shaft 15, and the pinion gears 16 and 17 mesh with each other and the axle shaft 7 respectively. Umbrella side gears 18, 1 fixed to
It is composed of 9 and the like.

Further, the inter-wheel differential device 9 has a differential lock mechanism (referred to as a differential lock) for stopping its differential function.
20 are provided. That is, this diff lock 20
As is well known, is intended to be used when escaping a car from mud, etc.
A spline 21 formed on the outer peripheral surface of one axle shaft 8, a spline 22 formed on the outer circumference of a hub that is axially adjacent to the spline 21 and fixed to the outer circumference of the differential case 14, and splines on the outer circumference of these splines 21, 22. A sleeve 23 that is engaged with and slidable in the axial direction, a fork 24 that is fitted in the outer circumferential groove of the sleeve 23 and that slides the axially, and the fork 24 is fitted and fixed. It is composed of a shift rod 25 that moves in the direction, an operating lever 26 for driving the shift rod 25, and the like. The diff lock 20 is in the off state in the state shown in FIG. 1 in which the sleeve 23 is engaged only with the spline 21 of the axle shaft 8, and the sleeve 23 slides leftward from the state shown in the figure to form the spline 21. When both splines 22 of the differential case 14 are engaged, the diff case 14 is turned on. When the diff lock 20 is turned on, the diff case 14 and the axle shaft 8 are integrated, so that the differential function of the inter-wheel differential device 9 is stopped, and both axle shafts 7 and 8 are stopped.
Will rotate together.

The inter-wheel differential device 9 and the diff lock 20 are provided in a diff casing 27, and the drive shaft 11 is surrounded by a carrier 28.

The clutch 10 includes a drive wheel 29 provided at the other end of a drive side axle shaft 8a having an output gear side gear 19 fixed to one end of the axle shaft 8, and one end facing the wheel 29. Front wheel 6
Driven wheel 30 provided on the other end of the driven shaft axle 8b, a sleeve 31 engaged with a spline formed on the outer circumferences of these wheels 29, 30, and an outer circumference of this sleeve 31. The fork 32 is fitted in the groove and slidably moves in the axial direction, and the fork 32 is fixed and includes a shift rod 33 for driving the fork 32. The sleeve 31 is engaged only with the spline of the driven wheel 30.
In the illustrated state, the clutch 10 is the axle shaft 8
When the sleeve 31 is in the disengaged state in which the output transmission paths of a and 8b are blocked, and the sleeve 31 slides to the left from the illustrated state and engages with both the driven wheel 30 and the wheel 29,
The clutch 10 is in a state where the output transmission paths of the axle shafts 8a and 8b are connected.

FIG. 3 shows a block configuration for 2-4 wheel drive switching and diff lock control. When a 2-4 switching command S is input to the controller 34, the diff lock actuator for turning on / off the diff lock 20 from the controller 34. Drive signals are output to the clutch actuator 35 for connecting and disconnecting the clutch 35 and the clutch 10, respectively. Then, when the controller 34 connects the clutch 10 based on the switching command from the two-wheel drive to the four-wheel drive, the diff lock 2 is preceded by this.
It includes a differential lock control device for turning on 0 and synchronizing the driven wheel 30 of the clutch 10 and the coupling side of the side gear 19, that is, the drive wheel 29. Further, the operation input D for the purpose of using the normal diff lock is manually input to the diff lock actuator 35. In addition, each actuator 3
Reference numerals 5 and 36 are constituted by negative pressure type or electric type motors, which drive the operating lever 26 of the diff lock 20 and the shift rod 33 of the clutch 10, respectively.

Next, the operation of the above configuration will be described with reference to FIG. Turning on and off the hub clutch of the two-wheel / four-wheel switching mechanism in the transfer device 2 switches between four-wheel and two-wheel drive,
In the case of two wheels, in this embodiment, the rear wheels are driven and the front wheels are idle wheels. This two-wheel drive state (time t − in FIG. 4)
During a period of t ₁ ), the clutch 10 provided on one axle shaft 8 on the idler wheel side is in the disengaged state. As a result, as described above, the back drive by the one front wheel 5 of the idle wheels is performed by the side gear 1 of the inter-wheel differential device 9.
8 to the drive-side axle shaft 8a and the drive-side wheel 29 of the clutch 10 via the pinion gears 16 and 17, and the side gear 19, but not to the drive shaft 11 and the propeller shaft 4 having a large mass, so that mechanical loss occurs. Is suppressed. Back drive by the other front wheel 6 causes the driven shaft axle 8b and the driven wheel 30 of the clutch 10 to rotate, and the opposed wheels 29 and 30 of the clutch 10 rotate in opposite directions at a high relative speed. Has been made.

Next, the operation of switching from the two-wheel drive to the four-wheel drive will be described. When the switching command S from the two-wheel drive to the four-wheel drive (2-4WD) is input to the controller 34 at time t ₁ , first, The diff lock 20 is turned on via the diff lock actuator 35, and after a short delay, the time t
₂ , the clutch 10 is connected via the clutch actuator 36, and then the hub clutch of the two-wheel / four-wheel switching mechanism is turned on. Clutch 1 like this
By operating the diff lock 20 prior to the connection of 0, the rotation of the side gear 18 due to the back drive of the front wheels 5 is directly transmitted to the side gear 19 via the diff case 14 and the pinion gears 16 and 17, and thus is connected to the side gear 19. The drive side wheel 29 of the clutch 10 is driven to rotate in the same direction as the rotation of the sub drive side wheel 30 which is opposed to this and is back-driven by the front wheels 6, and the vehicle is not traveling in a curve or the like.
If the vehicle is traveling straight, the rotation speeds of both are synchronized. Since the clutch 10 is connected in this state, a synchronizing (synchronizing) device is not required for connecting the clutch, or
There is no need to stop the car each time. Incidentally, the process proceeds to a four-wheel drive by turning on the hub clutch at time t _3, then at time t _4, off the differential lock 20, a conventional four-wheel drive cars.

Next, describing the operation of switching from the four-wheel drive to two-wheel drive, at time t _5, when a two-wheel driving (2WD) command is input to the controller 34, firstly, the hub clutch is turned off, then the time t _{At 6} , the clutch 10 is disengaged, and normal two-wheel drive traveling is started.

In general, the diff lock 20 is operated by a manual operation input D in order to escape from a muddy or the like, and is originally manufactured to be used when the rotational speed is relatively different. Therefore, as described above, there is no support for using the clutch 10 at the time of 2-4WD switching and before connecting the clutch 10.

Further, in the above-described embodiment, the case where the front wheel becomes the idle wheel at the time of driving the two wheels has been described. Conversely, when the rear wheel becomes the idle wheel, the rear wheel side may be provided with the same configuration as above. .

(Effects of the Invention) As described above, according to the present invention, the output is transmitted from the output gear of the inter-wheel differential device on the wheel side, which is equipped with the two-wheel / four-wheel switching mechanism and becomes the idle wheel during two-wheel drive. A clutch is provided on one side of the axle shaft, and a differential lock mechanism is provided in the differential device, and the differential lock mechanism is actuated when the clutch is engaged based on a command for switching from two-wheel drive to four-wheel drive, and the clutch is operated. Since it is designed to synchronize the driven side of the above with the output gear connecting side, there is no need to use a special synchronizing device for clutch connection as in the conventional case, and the structure can be simplified and space is saved. It can greatly contribute to cost reduction.

[Brief description of drawings]

FIG. 1 is a plan sectional view of an essential part of an axle device for a four-wheel drive vehicle according to an embodiment of the present invention, FIG. 2 is a plan view of the axle device, and FIG. 3 is a block diagram of a control device for the axle device. FIG. 4 is a time chart for explaining the operation of the axle device. 1 ... Transmission, 2 ... Transfer device (built-in hub clutch), 5, 6 ... Front wheels, 7, 8 ... Axle shaft, 8a ... Drive side axle shaft, 8
b ... Axle shaft on driven side, 9 ... Actuator between wheels, 10 ... Clutch, 19 ... Side gear, 20 ...
Differential lock mechanism (differential lock), 34 ...
controller.

Claims (1)

[Claims] 1. A transfer device having a pair of output shafts for transmitting the rotation of an input shaft to a wheel-to-wheel differential device provided between each of front and rear wheels, comprising a two-wheel / four-wheel switching mechanism. In the axle device of a four-wheel drive vehicle, a clutch that cuts off this transmission path is provided on one of the axle shafts to which output is transmitted from the output gear of the wheel-to-wheel differential device on the wheel side that is an idle wheel when driving two wheels. , A differential lock mechanism is provided in the differential device, and the differential lock mechanism is operated when the clutch is connected based on a switching command from two-wheel drive to four-wheel drive, and the differential drive mechanism and the output of the clutch are output. An axle device for a four-wheel drive vehicle comprising a differential lock control device for synchronizing with a gear connection side.