JP3183059B2 - Differential device for four-wheel drive vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a differential device for a four-wheel drive vehicle capable of selecting two-wheel drive or four-wheel drive.

[0002]

2. Description of the Related Art Conventional 2WD and 4WD can be selected.
In a wheel drive vehicle, on the axle side that is driven only at 4WD, the wheels rotate the drive shaft at 2WD, which is a resistance and is one of the causes of the deterioration of the fuel efficiency performance at 2WD. In order to solve this problem, an axle disconnect mechanism (ADD mechanism) or a freewheel hub mechanism is conventionally known.

[0003] JP-A-56-135320 discloses A
A differential device with a DD mechanism is described. This is a combination of a pinion gear that rotates integrally with the propeller shaft, a ring gear that meshes with the pinion gear and reduces the rotation from the propeller shaft, and a ring gear that appropriately distributes the rotation of the ring gear to the left and right wheels. It has a differential gear. The differential gear is a differential case to which the ring gear is connected,
The differential case carries a pinion mate attached to a pinion mate shaft. The pinion mate meshes with left and right side gears, and left and right stub shafts are splined to each side gear. One of the stub shafts is connected to the drive shaft so as to be able to transmit power at all times, and the other stub shaft is connected to the drive shaft via an ADD mechanism. The ADD mechanism has a spline at an end of the stub shaft facing the drive shaft and an end of the drive shaft facing the stub shaft. A spline line is connected to the spline of the stub shaft so as to be movable in the axial direction. ing. The sleeve is moved in response to a driver's operation, and power is transmitted between the stub shaft and the drive shaft via the sleeve when the sleeve is moving toward the drive shaft. Therefore, in this case, it functions as a normal final reduction gear. Further, when the sleeve moves to the side gear side, the stub shaft and the drive shaft are not connected, so that no power is transmitted between the stub shaft and the drive shaft. This state is the ADD mechanism ON state, and the ADD mechanism is turned off at the time of 2WD.
In the N state, the rotation of the front wheels does not cause the rotation of the propeller shaft, so that the fuel efficiency at the time of 2WD is improved.

When one of the left and right wheels idles, power is not transmitted to the other wheel due to the action of the differential gear, and the running performance is reduced. In order to solve this problem, a differential lock mechanism has been conventionally known. The Pajero New Car Manual (issued by Mitsubishi Motors, January 1991) describes a rear wheel final reduction gear equipped with a differential lock mechanism. It includes a driven cam that rotates integrally with the right side gear and has a dog clutch, a drive cam that faces the driven cam and rotates integrally with the differential case and has a dog clutch, and an actuator that moves the drive cam in the driven cam direction.

[0005] In the free state, there is nothing to prevent the differential between the left and right drive shafts from occurring.
Functions as a normal differential. The actuation of the actuator causes the drive cam to move in the driven cam direction, and is locked when the dog clutch engages. At this time, since the differential case and the right side case are integrated, no differential between the left and right drive shafts can be made. For this reason,
Even if one of the wheels spins, the rotational power is reliably transmitted to the other wheel, so that the running performance is improved.

[0006] Further, in the above-mentioned new vehicle manual, a freewheel hub is described, which prevents manual transmission of power between one wheel and the hub at the time of 2WD. And Japanese Patent Application Laid-Open No. 56-135320.

[0007]

However, in the above-mentioned conventional example, the ADD mechanism and the differential lock mechanism have the effect of improving the fuel consumption performance or the running performance at the time of 2WD, respectively. is not. As for the differential lock mechanism, it may be desirable to provide the differential lock mechanism not only on the rear wheel side but also on the front wheel side in a situation where the driving conditions are further deteriorated. If the above conventional examples are simply combined in order to achieve both of these performances, there is a problem that the structure and operation become complicated.

The present invention realizes a configuration in which the improvement in power performance during four-wheel drive and the improvement in fuel economy during two-wheel drive can be achieved by simple operation.

[0009]

According to a first aspect of the present invention, there is provided a differential device for a four-wheel drive vehicle, which is used in a four-wheel drive vehicle capable of switching between 2WD and 4WD. In a differential device that transmits rotational power from only the propeller shaft to the left and right wheels via drive shafts, an ADD mechanism that inhibits transmission of rotational power between the drive shaft and the propeller shaft during 2WD, A differential lock mechanism for inhibiting transmission of rotational powers having different rotational speeds to the left and right drive shafts is provided.

Further, the differential device includes a differential case to which the rotational power from the propeller shaft is transmitted, and a plurality of gears provided in the differential case, which appropriately distribute the rotational power to the differential gear case to the left and right. And a first sleeve spline-coupled to the outer peripheral portion of one of the drive shafts so as to be movable in the axial direction. When the first sleeve is located on the differential gear side (first In the sleeve ON state), the first
One of the drive shaft and one of the plurality of gears of the differential gear is connected via a sleeve so that rotational power can be transmitted, and a second sleeve spline-connected to an outer peripheral portion of the first sleeve so as to be movable in an axial direction. When the second sleeve is located on the differential case side (second sleeve ON state), the second sleeve
The differential case and one of the drive shafts are connected via a sleeve so that rotational power can be transmitted, and the ADD mechanism is turned on when the first sleeve is turned off and the second sleeve is turned off. When the second sleeve is ON, the differential lock state is 4WD, and when the first sleeve is ON and the second sleeve is OFF, the normal 4WD is adopted.

According to another aspect of the present invention, there is provided a differential device for a four-wheel drive vehicle, wherein the plurality of gears of the differential gear are provided in a center of the ring gear in the differential case. A pinion mate shaft fixed perpendicular to the axis, a pinion mate provided rotatably on the pinion mate shaft, and rotatably provided in the differential case coaxially with a ring gear on the left and right of the pinion mate shaft, Left and right side gears meshing with the pinion mate, and a first sleeve spline-connected to an outer peripheral portion of one of the drive shafts so as to be movable in an axial direction, and the first sleeve is a differential gear. Side (when the first sleeve is ON),
One drive shaft and one side gear are connected to each other via the first sleeve so as to transmit rotational power, and a second sleeve is spline-connected to an outer peripheral portion of the first sleeve so as to be movable in an axial direction. When the second sleeve is located on the differential case side (second sleeve ON state), the differential case and one of the drive shafts are connected via the second sleeve so as to be able to transmit rotational power, and the first sleeve is The ADD mechanism is turned on when the second sleeve is turned off and the second sleeve is turned off.
When the sleeve is ON and the second sleeve is ON, the differential lock state is 4WD, and when the first sleeve is ON and the second sleeve is OFF, the normal 4WD is set.

[0012]

According to the above method, in the differential device for a four-wheel drive vehicle according to the first aspect of the present invention, the transmission of rotational power from the drive shaft to the propeller shaft is inhibited by the ADD mechanism at the time of 2WD, and the differential lock is transmitted at the time of 4WD. When the mechanism is actuated, transmission of rotational powers of different rotational speeds to the left and right drive shafts is prohibited, and even in a situation where one wheel idles, power is transmitted to the other wheel, It is possible to achieve both the improvement of the running performance at the time of 4WD and the improvement of the fuel efficiency performance at the time of 2WD.

Further, an ADD mechanism and a differential lock mechanism are constituted by a first sleeve provided on the outer peripheral portion of the drive shaft and a second sleeve provided on the outer peripheral portion of the first sleeve. A by operation
Since the DD mechanism and the differential lock mechanism can be selected, it is possible to achieve both the improvement of the traveling performance at the time of 4WD and the improvement of the fuel efficiency at the time of 2WD with a simple configuration and a simple operation.

According to a second aspect of the present invention, there is provided a differential device for a four-wheel drive vehicle, wherein the differential case includes a differential gear composed of a pinion mate and left and right side gears. A first sleeve provided on the portion,
By the second sleeve provided on the outer peripheral portion of the sleeve, A
Since the DD mechanism and the differential lock mechanism are configured, the ADD mechanism and the differential lock mechanism can be selected by operating the two sleeves.
It is possible to achieve both the improvement of the driving performance at the time of D and the improvement of the fuel efficiency performance at the time of 2WD.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings. Two-wheel drive (hereinafter 2WD) and four-wheel drive (hereinafter 4WD), consisting of a final gear that reduces the rotational power from a propeller shaft (not shown) and a differential gear 3 that transmits to the left and right wheels via a drive shaft, respectively, can be switched. And a front-wheel final reduction gear (differential device) 1 for a four-wheel drive vehicle that constantly drives the rear wheels. The axle disconnect mechanism (hereinafter referred to as an ADD mechanism) for inhibiting transmission of rotational power from the drive shaft to the propeller shaft during 2WD. ) And a differential lock mechanism for inhibiting transmission of rotational powers having different rotational speeds to the left and right drive shafts at the time of 4WD.

The final gear includes a drive pinion that rotates integrally with the propeller shaft, and a ring gear 2 that meshes with the drive pinion. The differential gear 3 includes a differential case 3C integrally coupled to the ring gear 2, a pinion mate shaft 3S fixed in the differential case 3C perpendicular to the center axis of the ring gear 2, and
A pinion mate 3P rotatably provided on the pinion mate shaft 3S, a left side gear 3L rotatably provided in the differential case 3C on the left side of the pinion mate shaft 3S coaxially with the ring gear 2, and meshing with the pinion mate 3P; The right side gear 3R rotatably provided in the right side of the pinion mate shaft 3S in the 3C and coaxial with the ring gear 2 and meshing with the pinion mate 3P.
And, it consists of.

A first sleeve S1 is spline-connected to the outer periphery of the right drive shaft 4R so as to be movable in the axial direction. A dog clutch S1C is formed at an end of the first sleeve S1 on the differential gear 3 side, and when the first sleeve S1 is located on the differential gear 3 side (first sleeve ON state), the right side gear 3R. The dog sleeve 3RC and the dog clutch S1C formed on the first sleeve S1
1, the right drive shaft 4R and the right side gear 3R are connected so as to be able to transmit rotational power.

Further, a second sleeve S spline-connected to the outer peripheral portion of the first sleeve S1 so as to be movable in the axial direction.
Two. A dog clutch S2C is formed at an end of the second sleeve S2 on the differential case 3C side, and
When the sleeve S2 is located on the differential case 3C side (second sleeve ON state), the dog clutch 3CC and the dog clutch S2C formed on the differential case 3C are engaged with each other, so that the differential case 3C and the right drive are driven via the second sleeve S2. The shaft 4R is connected so as to be able to transmit rotational power.

Here, the first sleeve is in the OFF state and the second sleeve is in the second state.
The ADD mechanism is turned on when the sleeve is turned off
State, the first sleeve ON state and the second sleeve O
In the N state, the differential lock state becomes 4WD, and when the first sleeve is in the ON state and the second sleeve is in the OFF state, it becomes a normal 4WD. Also, when the first sleeve S1 is located on the wheel side (first sleeve OFF state), the right drive shaft 4R and the right side gear 3R are not connected, and the rotational power cannot be transmitted, and When the second sleeve S2 is located on the wheel side (the second sleeve O
In the FF state), the differential case and the right drive shaft 4R are not connected so as to be able to transmit rotational power.

A left drive shaft 4L is connected to the left side gear 3L so as to be always rotatable.
Grooves S1M and S2M are formed in the first sleeve S1 and the second sleeve S2, respectively, and shift forks (not shown) are engaged with the grooves S1M and S2M, respectively.
The shift fork is linked to a shift lever operated by the driver. For this reason, selection of an ADD mechanism and a differential lock mechanism is attained by a driver operating in a cab.

The operation will be described below. Each mechanism operates according to the state of each sleeve as shown in FIG. In the case of 2WD, the first sleeve is off and the second sleeve is off.
When this state occurs, the ADD mechanism is turned on, and the rotational power from the front wheels is not transmitted to the propeller shaft by the following operation. In the ADD mechanism ON state, since the right drive shaft 4R and the right side gear 3R are not connected, the rotational power from the right wheel is transmitted only to the right drive shaft 4R. Since the left drive shaft 4L is always connected to the left side gear 3L, the rotational power from the left wheel is supplied to the left drive shaft 4L.
Up to L is transmitted. Here, since the right side gear 3R rotates according to the rotation of the pinion mate 3P meshing therewith, the right side gear 3R tries to rotate in the opposite direction to the left side gear 3L according to the pinion mate 3P rotated by the rotation of the left side gear 3L. Here, since the right side gear 3R and the right drive shaft 4R are not connected, rotation in the opposite direction to the left side gear 3L is possible. Therefore, the pinion mate shaft 3S does not rotate and the ring gear 2 remains stopped.

Therefore, the propeller shaft is not rotated at the time of 2WD, so that the fuel efficiency at the time of 2WD is improved. In the case of 4WD, normal 4WD and 4WD in a differential lock state can be selected. When the first sleeve is ON and the second sleeve is ON, the differential lock state is 4WD, and when the first sleeve is ON and the second sleeve is OFF, the normal 4WD is obtained.

When the differential lock mechanism is ON, the rotation of the ring gear 2 is transmitted directly to the right drive shaft 4R. Therefore, since the right side gear 3R always rotates integrally with the ring gear 2, the pinion mate 3P does not rotate, and the left side gear 3L also rotates at the same rotation speed as the right side gear 3R. For this reason, even if one of the wheels spins, the power is reliably transmitted to the other wheel, and the traveling performance on a rough road is improved.

When the normal 4WD is selected,
Since the right drive shaft 4R and the right side gear 3R are connected, the same operation as that of the conventional differential gear is performed. As described above, in the above-described embodiment, AD
2WD by using D mechanism and differential lock mechanism together
The improvement of the fuel consumption performance at the time and the improvement of the traveling performance at the time of 4WD can be compatible. Further, since the ADD mechanism and the differential lock mechanism are configured by the first sleeve S1 and the second sleeve provided on the drive shaft, the configuration is simple, and the selection between the ADD mechanism and the differential lock mechanism can be performed by a simple operation. Can be.

[0025]

As described above, in the differential device for a four-wheel drive vehicle according to the first aspect of the present invention, the transmission of rotational power from the drive shaft to the propeller shaft is inhibited during 2WD by the ADD mechanism. When the differential lock mechanism is operated, transmission of rotational powers having different rotational speeds to the left and right drive shafts is prohibited, and power is transmitted to the other wheel even in a situation where one wheel idles. . For this reason, it is possible to achieve both improvement of the traveling performance at the time of 4WD and improvement of the fuel efficiency performance at the time of 2WD. In addition, when the present invention is combined with the present invention using a differential lock mechanism conventionally used on the rear wheel side, differential lock can be performed on the front and rear wheels, and traveling performance in a situation where traveling conditions are worse is improved.

Further, an ADD mechanism and a differential lock mechanism are constituted by a first sleeve provided on the outer peripheral portion of the drive shaft and a second sleeve provided on the outer peripheral portion of the first sleeve. A by operation
Since the DD mechanism and the differential lock mechanism can be selected, it is possible to achieve both the improvement of the traveling performance at the time of 4WD and the improvement of the fuel efficiency at the time of 2WD with a simple configuration and a simple operation.

According to a second aspect of the present invention, there is provided a differential device for a four-wheel drive vehicle, wherein a differential case comprising a pinion mate and left and right side gears in a differential case is provided. A first sleeve provided on the portion,
By the second sleeve provided on the outer peripheral portion of the sleeve, A
Since the DD mechanism and the differential lock mechanism are configured, the ADD mechanism and the differential lock mechanism can be selected by operating the two sleeves.
It is possible to achieve both the improvement of the driving performance at the time of D and the improvement of the fuel efficiency performance at the time of 2WD.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention.

FIG. 2 is an operation explanatory view of an embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Front wheel final reduction gear, 2 ... Ring gear, 3 ... Differential gear 3C ... Differential case, 3R ... Right side gear, 4R ... Right drive shaft S1 ... 1st sleeve, S2 ... 2nd sleeve

Claims (2)

(57) [Claims] The present invention is used in a four-wheel drive vehicle capable of switching between two-wheel drive (hereinafter, 2WD) and four-wheel drive (hereinafter, 4WD). Only in 4WD, the rotational power from the propeller shaft is applied to the left and right wheels, respectively. An axle disconnect mechanism (hereinafter referred to as an ADD mechanism) for inhibiting transmission of rotational power between the drive shaft and the propeller shaft during 2WD, and a different drive mechanism for the left and right drive shafts during 4WD. A differential lock mechanism for inhibiting transmission of rotational power of the rotational speed; a differential device for the four-wheel drive vehicle; a differential case for transmitting rotational power from the propeller shaft; and a differential gear provided in the differential case, Distribute the rotational power transmitted to the case to the left and right as appropriate A differential gear composed of a number of gears, and a first sleeve spline-coupled to an outer peripheral portion of one of the drive shafts so as to be movable in the axial direction, and the first sleeve is positioned on the differential gear side. At this time (when the first sleeve is ON), one of the drive shafts and one of the plurality of gears of the differential gear is connected via the first sleeve so as to be able to transmit rotational power, and an outer periphery of the first sleeve is provided. A second sleeve spline-connected to the portion so as to be movable in the axial direction. When the second sleeve is located on the differential case side (second sleeve ON state), the second sleeve is connected to the second sleeve via the second sleeve. The differential case and one of the drive shafts are connected so as to be able to transmit rotational power. When the sleeve is turned off, the ADD mechanism is turned on. When the first sleeve is turned on and the second sleeve is turned on, the differential lock state becomes 4WD. When the first sleeve is turned on and the second sleeve is turned off, the normal operation is performed. A differential device for a four-wheel drive vehicle, wherein the differential device is 4WD. 2. The differential gear according to claim 1, wherein the plurality of gears of the differential gear are rotatably provided on the pinion mate shaft fixed vertically to a center axis of the ring gear in the differential case, and rotatably provided on the pinion mate shaft. A pinion mate, and left and right side gears rotatably provided in the differential case on the left and right sides of the pinion mate shaft and coaxial with the ring gear and meshing with the pinion mate. A first sleeve spline-coupled to the outer peripheral portion so as to be movable in the axial direction is provided. When the first sleeve is located on the differential gear side (first sleeve ON state), the first sleeve is connected to the first sleeve via the first sleeve. The drive shaft and one of the side gears are connected so as to be capable of transmitting rotational power. A second sleeve which is axially movable spline-coupled to the outer peripheral portion of the first sleeve, when the second sleeve is positioned on the differential case side (second
In the sleeve ON state), the differential case and one of the drive shafts are connected via the second sleeve so as to be capable of transmitting rotational power, and the ADD mechanism is turned on by being in the first sleeve OFF state and the second sleeve OFF state. 2. A differential lock 4WD in the first sleeve ON state and the second sleeve ON state, and a normal 4WD in the first sleeve ON state and the second sleeve OFF state. A differential device for a four-wheel drive vehicle according to claim 1.