JPH11217027A - Transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate specification change of a two-wheel drive type and a four wheel drive type after assembling of a transmission. SOLUTION: A transmission comprises a casing 10, an input shaft 20 supported in the casing 10, and operationally connected to a driving source, an output shaft 40 supported in the casing 10, and transmitting driving force from the input shaft 20 to a pair of right and left rear shafts, and a power extracting gear 42 for a front wheel driving dis-rotatably supported relatively to the output shaft 40. In addition, a through-hole 13 is formed on a front wall 10a of the casing 10. At least a teeth top of the power take-off gear 42 faces to the through hole 13 to mesh with a driving gear 51 when one end of a front wheel driving shaft 52, which supports at its one end the driving gear 51, is inserted in the through-hole 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission for a vehicle such as a tractor, and more particularly, to a transmission that can easily change specifications between a two-wheel drive type and a four-wheel drive type after the transmission is assembled.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. Hei 9-93679 discloses that a transmission for transmitting driving force from a driving source to a pair of left and right rear axles is provided with a front wheel driving unit for extracting front wheel driving force. As is known in the art, such a conventional transmission has been manufactured on different manufacturing lines for the two-wheel drive type and the four-wheel drive type.

That is, in the conventional transmission, it is necessary to select whether or not the front wheel drive unit is housed in a casing according to the specification of the two-wheel drive type or the four-wheel drive type at the time of assembling the transmission. Because of the configuration, it was necessary to manufacture both types on separate lines, and it was difficult to improve transmission assembly efficiency and inventory management efficiency.

In such a configuration, if there is a request to change the specifications between the two-wheel drive type and the four-wheel drive type after assembling the transmission, disassemble the transmission itself and then mount or remove the front wheel drive unit. It is not easy to make such a specification change after the vehicle is shipped, since it is necessary to make such a change.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is possible to manufacture both a four-wheel drive type and a two-wheel drive type transmission on the same manufacturing line. It is an object of the present invention to provide a transmission capable of easily changing specifications between types.

[0006]

In order to achieve the above object, the present invention provides a casing, an input shaft supported in the casing and operatively connected to a driving source, and supported in the casing. An output shaft that transmits the driving force transmitted from the input shaft to the pair of left and right rear axles, and a power take-out gear that is non-rotatably supported on the output shaft so that front-wheel drive power can be taken out. A through hole is formed in the casing front wall, and the power take-out gear is connected to the transmission gear when the one end of the front wheel drive shaft supporting the transmission gear at one end is inserted into the through hole. A transmission is provided in which at least the tooth tips face the through holes so that they can engage.

Preferably, the input shaft is disposed along the longitudinal direction of the vehicle at a position displaced to one side in the casing width direction, and the casing has a bulging portion projecting to the other side in the casing width direction. And the through hole may be formed at a position in front of the bulging portion.

A front wheel drive unit having a transmission gear meshing with the power take-out gear and a front wheel drive shaft supporting the transmission gear is detachably provided, and the transmission gear has an outer diameter smaller than the through hole. And the front wheel drive shaft is
A rear end may be supported by the rear wall of the bulging portion.

Preferably, the front wheel drive unit may have a clutch between the front wheel drive shaft and the transmission gear that allows the front wheel drive shaft to rotate faster than the transmission gear. .

[0010] The casing front wall may be formed by a clutch housing rear wall located in front of the transmission in a vehicle longitudinal direction.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a transmission according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a diagram schematically showing a four-wheel drive type vehicle equipped with a transmission according to the present embodiment, FIG. 2 is a plan sectional view of the transmission according to the present embodiment, and FIG. It is an enlarged view of a unit part.

Transmission 1 according to the present embodiment
As shown in FIG. 1, is located immediately behind the clutch 110 that connects or disconnects the driving force from the engine 100 in the vehicle longitudinal direction. In the figure, 130 is a front wheel, 140 is a rear wheel, and 120 is a propeller shaft for transmitting a driving force from a transmission to a front wheel.

As shown in FIG. 2, the transmission 1 includes a casing 10 and an input shaft 20 housed in the casing on one side in the vehicle width direction and along the vehicle longitudinal direction.
And an intermediate shaft 30 and an output shaft 40 arranged substantially in parallel from the input shaft 20 to the other side in the vehicle width direction.

The casing 10 has a main body 11 for accommodating the input shaft 20, the intermediate shaft 30, and the output shaft 40, and a bulging portion 12 bulging from the main body 11 to the other side in the vehicle width direction. I have. The bulging portion 12 is formed on the rear wall 1 rising outward from the front end of the other side wall 11 a in the width direction of the main body 11.
2a and a side wall 12b rising forward from an outer end of the rear wall. Both the body 11 and the bulging portion 12 of the casing are open at the front.

The front opening of the casing is closed by a housing rear wall 111 of the clutch, and the input shaft 20, the intermediate shaft 30, and the output shaft 40 are connected to the clutch housing rear wall 111 and the casing rear wall 1 respectively.
0b so as to be rotatable. That is, the rear wall 111 of the clutch housing is
a. A through hole 13 is formed in a portion of the clutch housing rear wall 111 facing the bulging portion 12.

The input shaft 20 has a fourth-gear to fifth-gear gear pair 21.
Are supported rotatably and non-slidably in the axial direction. On the other hand, the intermediate shaft 30 has a reverse-first gear pair 31 and 2
A third-speed gear pair 32 is supported rotatably and non-slidably in the axial direction. Each gear pair is provided with a shifter between the gears. The shifter is supported so as not to rotate relative to each shaft and to be slidable in the axial direction.

The input shaft 20 has a reverse-1 speed gear pair 3
A gear that constantly meshes with the 1st and 2nd and 3rd gear pairs 32 and a gear that constantly meshes with the 4th and 5th gear pairs 21 are provided on the intermediate shaft 30 so as to be relatively non-rotatable. Therefore, the desired rotation of the intermediate shaft 30 can be obtained by sliding the shifter in any one of the gear trains to one side and rotating the one gear synchronously with the shifter.

The intermediate shaft 30 is connected to an output shaft 40 via a gear. An output gear 41 is provided at the rear end of the output shaft 40 so as not to rotate relatively. The output gear 41 meshes with an input gear of a differential gear 60 that transmits driving force to a pair of left and right axles 70. On the other hand, at the front end of the output shaft 40, a power take-out gear 42 for taking out the power for driving the front wheels is supported so as not to rotate relatively. As shown in FIGS. 2 and 3, the power take-out gear 42 has at least a tooth tip at a clutch housing rear wall 111, that is,
It is arranged so as to face the through hole 13 of the casing front wall 10a.

A swelling portion 12 of the casing has a transmission gear 51 meshed with the power take-out gear 42, and a transmission gear 51
And a front wheel drive unit 50 having a front wheel drive shaft 52 for supporting the front wheel drive shaft. The front wheel drive unit 50 is fixed to the casing 10 by a mounting member 53 that supports the front wheel drive shaft 52 as a bearing. The transmission gear 51 has an outer diameter smaller than the through hole 13 of the casing. The rear end of the front wheel drive shaft 52 is rotatably supported by the bulging portion rear wall 12a via a bearing. Further, the front wheel drive unit 50 includes a clutch between the transmission gear 51 and the front wheel drive shaft 52 that allows the front wheel drive shaft 52 to rotate faster than the transmission gear 51. As shown in FIGS. 2 and 3, the clutch is preferably a dual type including a clutch 54 that operates at the time of forward movement and a clutch 55 that operates at the time of reverse movement.

According to the transmission according to the present embodiment, the following effects can be obtained.

That is, a through hole 13 is formed in the front wall 10a of the transmission casing, and a power take-out gear 42 that rotates synchronously with the rear wheel drive system is provided so that at least the tooth tip faces the through hole 13. Since the outer diameter of the transmission gear meshing with the power take-out gear 42 is smaller than that of the through hole 13, the specification change between the four-wheel drive type and the two-wheel drive type while the engine and the transmission are mounted on the vehicle body. Can be easily performed. That is, in this embodiment, as shown in FIG. 4, by attaching the through hole closing plate 90 instead of the front wheel drive unit 50, a two-wheel drive type can be easily achieved.

According to such a configuration, only a two-wheel drive type transmission is prepared at the factory, and if a four-wheel drive type is desired, the front wheel drive unit is mounted on the two-wheel drive type transmission. This makes it possible to improve the efficiency of the transmission assembling work and the efficiency of inventory management, and reduce the cost by sharing the casing and the like.

In the present embodiment, clutches 54 and 55 are provided between the transmission gear 51 and the front wheel drive shaft 52 to allow the front wheel drive shaft 52 to rotate faster than the transmission gear 51. Since the vehicle is interposed, it is possible to effectively prevent the front wheel from being roughened by the front wheels and the front wheels from being worn due to a difference in turning radius when the vehicle turns.

That is, during turning of the vehicle, a difference in rotation occurs between the front wheel and the rear wheel located on the same side due to a difference in turning radius. Therefore, if the output shaft and the front wheel drive shaft are connected so as to always rotate in the same manner, the front wheels slip during turning of the vehicle, thereby causing roughening of the ground contact surface and wear of the front wheels.

On the other hand, in the present embodiment, since a clutch that allows the front wheel drive shaft to rotate faster than the output shaft is interposed between the transmission gear and the front wheel drive shaft, the vehicle turns. At times, the front wheels may rotate faster than the rear wheels. Accordingly, slip of the front wheels during turning of the vehicle is effectively prevented, and thereby, it is possible to effectively prevent the front wheels from being roughened by the front wheels and the front wheels from being worn.

Further, in the present embodiment, since the front wheel drive unit 50 is disposed in the casing bulging portion 12, the entire casing width does not need to be large enough to accommodate the front wheel drive unit. In addition, the size of the four-wheel / two-wheel drive transmission can be reduced.

Since the input shaft 20 is disposed on one side in the vehicle width direction and the casing bulge 12 is provided on the other side in the vehicle width direction, the transmission height does not increase due to the attachment of the front wheel drive unit 50. . Therefore, in the four-wheel drive specification, the position of the center of gravity of the vehicle does not move upward, so that the running stability does not deteriorate. Further, the rear end of the front wheel drive shaft 52 is connected to the bulging portion rear wall 1.
Since it is supported by 2a, power transmission from the output shaft 40 to the front wheel drive shaft 51 can be performed stably.

[0028]

According to the transmission of the present invention, the power take-off gear for driving the front wheel, which is non-rotatably supported on the output shaft, is configured so that at least the tooth tip faces the through hole provided in the front wall of the casing. After the transmission is assembled, the specifications can be easily changed from the two-wheel drive type to the four-wheel drive type. Therefore, a single transmission can be used for both the two-wheel drive type and the four-wheel drive type, thereby improving the assembly workability and increasing the efficiency of inventory management.

If the input shaft is arranged on one side in the width direction of the casing and the through hole is formed in a portion opposed to a bulge formed to protrude on the other side in the width direction of the casing, the entire width of the transmission can be used as a front wheel drive unit. It is not necessary to have a width that can be accommodated, and the transmission can be made compact. In addition, even when the front wheel driving force take-out unit is attached, the transmission height does not increase, so that the running stability does not deteriorate due to the increase in the center of gravity of the vehicle in the four-wheel drive specification.

A transmission gear having a diameter smaller than that of the through hole;
If the front wheel drive unit having the front wheel drive shaft supporting the transmission gear is detachably provided, the specification change from the four-wheel drive type to the two-wheel drive type can be easily performed. Further, if the rear end of the front wheel drive shaft is supported by the rear wall of the bulging portion, power transmission from the output shaft to the front wheel drive shaft can be performed stably.

Further, if a clutch is provided between the front wheel drive shaft and the transmission gear to allow the front wheel drive shaft to rotate faster than the transmission gear, the front wheels will be higher than the rear wheels when turning the vehicle. As a result, it is possible to effectively prevent the front wheels from slipping, thereby effectively preventing the ground contact surface from being roughened due to the front wheels slipping and the front wheels from being worn.

If the casing front wall is constituted by the clutch housing rear wall, the manufacturing cost of the casing can be reduced and the overall length of the vehicle can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a four-wheel drive type vehicle equipped with a transmission according to a first embodiment.

FIG. 2 is a cross-sectional plan view of the transmission according to the first embodiment.

FIG. 3 is an enlarged view of a front wheel drive unit of the transmission shown in FIG. 2;

FIG. 4 is a schematic view of a vehicle when the transmission shown in FIG. 2 is modified for two-wheel drive.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transmission 10 Casing 10a Casing front wall 11 Casing main body part 12 Casing bulging part 13 Through-hole 20 Input shaft 40 Output shaft 42 Power take-out gear 50 Front wheel drive unit 51 Transmission gear 52 Front wheel drive shaft 110 Clutch housing

Claims (5)

[Claims] 1. A casing, an input shaft supported in the casing and operatively connected to a drive source, and a pair of right and left rear axles supported in the casing and transmitted from the input shaft. An output shaft for transmitting the power for front wheel drive, and a power take-out gear that is supported by the output shaft so as to be relatively non-rotatable, and a through hole is formed in the front wall of the casing. The power take-off gear has at least a tooth tip facing the through-hole so that when the one end of the front wheel drive shaft supporting the transmission gear at one end is inserted into the through-hole, it can mesh with the transmission gear. Transmission. 2. The input shaft is disposed along a longitudinal direction of the vehicle at a position displaced to one side in a casing width direction, and the casing has a bulging portion projecting to the other side in the casing width direction. The transmission according to claim 1, wherein the through hole is formed at a position in front of the bulging portion. 3. A front wheel drive unit having a transmission gear meshing with the power take-out gear and a front wheel drive shaft supporting the transmission gear is detachably provided, and the transmission gear has an outer diameter larger than that of the through hole. 3. The transmission according to claim 2, wherein the rear end of the front wheel drive shaft is supported by the rear wall of the bulging portion. 4. 4. The front wheel drive unit further includes a clutch between the front wheel drive shaft and the transmission gear that allows the front wheel drive shaft to rotate faster than the transmission gear. A transmission according to claim 3. 5. The front wall of the casing is formed by a rear wall of a clutch housing located forward of the transmission.
The transmission according to any one of claims 1 to 4.