JPH06270702A - Transmission for vehicle - Google Patents

Abstract

PURPOSE:To provide a transmission for which seizure of a creep gear shaft due to the thrust, acting to ward the creep gear from a driven gear is prevented, and assembly there of is facilitated by providing the driven gear comprising a helical gear for transmitting the power from a bevel pinion shaft to a front wheel power taking-out shaft and the creep gear shaft, which makes its rotation relatively to the driven gear. CONSTITUTION:A peripheral groove is formed on a front wheel power taking-out shaft 3 located between a driven gear 14 and a creep gear shaft 7, and a half collar 23 for receiving the thrust from the driven gear 14 is fitted to this peripheral groove and a collar 26 for preventing the divided half collar 23 from disengaging from the peripheral groove by disengagedly fitted to the outer periphery of the divided half collar 23 is fitted on the front wheel power taking-out shaft 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle power transmission device such as a traveling system power transmission device for a tractor.

[0002]

2. Description of the Related Art A traveling system power transmission device incorporated in a tractor mission case is equipped with a bevel pinion shaft for inputting power from an engine to a rear wheel differential device. A front wheel power take-off shaft for transmitting power is provided, a pair of front and rear transmission gears are fixed on the bevel pinion shaft, and a pair of front and rear driven gears that always mesh with the front and rear power transmission gears are mounted on the front wheel power take-off shaft. It is fitted so that the front wheels travel at a faster speed than the rear wheels via the front transmission gear and the driven gear, and the front wheels and the rear wheels run at the same speed via the rear transmission gear and the driven gear. In addition to selectively transmitting power via a hydraulic clutch for traveling, power is transmitted from a transmission shaft that transmits power to a bevel pinion shaft via a creep speed change mechanism. That.

The creep speed change mechanism has a first transmission shaft.
A cylindrical shaft-shaped creep gear shaft equipped with a first large-diameter gear that is constantly meshed with a small-diameter gear is rotatably externally fitted to the front wheel power output shaft, and a second small-diameter gear provided on the creep gear shaft is mounted on the bevel pinion shaft. And a second large-diameter gear that selectively engages with the transmission shaft.

[0004]

In the above-mentioned conventional apparatus, since the front driven gear rotates at a relatively high speed, noise is generated in the spur gear. Therefore, the front driven gear and the transmission gear are generated. It is considered to configure the with a helical gear. However, if it is configured with a helical gear, thrust acts on the front or rear of the driven gear, and therefore thrust acts on the creep gear shaft from the driven gear either in reverse or forward,
The collar provided between the two is pressed against the creep gear shaft. Also, while the creep gear shaft rotates at a relatively low speed, when power is transmitted to the bevel pinion shaft without passing through the creep gear shaft, the driven gear rotates at a high speed, and the relative rotation between them is large. Therefore, seizure occurs on the contact surface between the creep gear shaft and the collar that contacts the creep gear shaft.

Therefore, an object of the present invention is to prevent seizure due to the thrust.

[0006]

The technical means taken by the present invention to achieve the above object is to provide a transmission gear 12 on a transmission shaft 2 to which power from an engine is transmitted, and the transmission gear 12 is provided. A power transmission gear 14 that engages with the power transmission shaft 3 is rotatably fitted over the power transmission shaft 3 so that power is transmitted from the power transmission shaft 2 to the power transmission shaft 3 via the power transmission gear 14. The driven gear 14 and the driven gear 14 are helical gears, and another transmission gear body 7 that rotates relative to the driven gear 14 is provided on the side of the driven shaft 3 on which the thrust from the driven gear 14 acts. In a vehicle power transmission device,
A circumferential groove 22 is formed on the driven shaft 3 between the driven gear 14 and another transmission gear body 7, and a half collar 23 for receiving the thrust from the driven gear 14 is fitted into the circumferential groove 22. The detachment preventing collar 26 is fitted on the driven shaft 3 so as to be detachably fitted to the outer periphery of the half-split collar 23 to prevent the half-split collar 23 from coming off the circumferential groove 22.

[0007]

The thrust acting from the driven gear toward the other transmission gear body on the driven shaft is received by the half collar fitted in the circumferential groove formed on the driven shaft, and from here It does not act on the transmission gear body, and seizure of the contact surface between the other transmission gear body and the collar in contact with this is prevented.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side cross-sectional view of a rear portion of a transmission case 1 that constitutes a vehicle body of a tractor. A bevel pinion shaft (transmission shaft) 2 is arranged in the front-rear direction in the middle of the upper and lower parts, and below the bevel pinion shaft 2. A front wheel power takeoff shaft (driven shaft) 3 is arranged in parallel with the bevel pinion shaft 2, and the bevel pinion shaft 2 and the front wheel power takeoff shaft 3 are mounted on the partition walls 1A, 1B, 1C in the mission case 1. It is rotatably supported via.

An auxiliary transmission shaft 4 of an auxiliary transmission mechanism is arranged in front of the bevel pinion shaft 2 so that rotational power from the engine can be transmitted to the auxiliary transmission mechanism via a clutch, a main transmission mechanism and the like. Has become. The main speed change mechanism (or the sub speed change mechanism or the like) is configured to rotate the rotational power forward and backward so that the tractor can move forward and backward. Power is transmitted from the auxiliary transmission shaft 4 to the bevel pinion shaft 2 via a creep transmission mechanism 5. The creep transmission mechanism 5 is spline-fitted to the rear end side of the auxiliary transmission shaft 4, and a first small-diameter gear 6, which is constantly meshed with the first small-diameter gear 6 and is rotatable on the front part of the front wheel power take-off shaft 3. The first large diameter gear 8 spline-fitted to the front portion of the creep gear shaft (transmission gear body) 7 fitted externally, the second small diameter gear 9 integrally formed on the rear portion of the creep gear shaft 7, and the front of the bevel pinion shaft 2. 2nd large diameter provided with a fitting portion 10 which is spline-fitted in the axial direction so as to be slidable in the axial direction, engages with the second small-diameter gear 9 in a disengageable manner, and which is spline-fitted in the rear end portion of the auxiliary transmission shaft 4 It is composed of a gear 11.

Therefore, the creep gear shaft 7 is constantly rotating at a low speed. Further, as shown in FIG. 1, when the fitting portion 10 is spline-fitted to the rear end portion of the auxiliary transmission shaft 4, power is transmitted to the bevel pinion shaft 2 at the same speed, and the second large-diameter gear is moved to the second gear.
When the small diameter gear 9 is engaged, the power is transmitted to the bevel pinion shaft 2 through the first small diameter gear 6, the first large diameter gear 8, the second small diameter gear 9 and the second large diameter gear, and the speed is reduced. Then, power is transmitted from the bevel pinion shaft 2 to the rear wheels via the rear wheel differential device.

A pair of front and rear transmission gears 12 and 13 are spline-fitted and fixed to the rear portion of the bevel pinion shaft 2, and the front and rear transmission gears 12 and 13 are always attached to the rear portion of the front wheel power take-off shaft 3. A pair of front and rear driven gears that engage with each other,
15 is loosely fitted, and a hydraulic clutch 16 is arranged between the front and rear driven gears 14, 15. The hydraulic clutch 16 includes a drive plate that rotates integrally with the clutch body 17, a clutch disk that rotates integrally with the front and rear driven gears 14 and 15, on both front and rear sides of a clutch body 17 key-connected to the front wheel power output shaft 3. It comprises hydraulic packs 18 and 19 composed of hydraulic pistons and the like for pressing them into contact with each other, and by selectively connecting them with the front and rear driven gears 14 and 15, the rotational power of the bevel pinion shaft 2 is transferred to the front transmission gear 12.
Alternatively, the rear transmission gear 13 transmits the power to the front wheel power output shaft 3, and the power is transmitted from the front wheel power output shaft 3 to the front wheels via the propulsion shaft, the front wheel differential device, and the like.

When power is transmitted from the rear transmission gear 13, the front and rear wheels travel at substantially the same speed, and the front transmission gear 1
The diameter of the rear transmission gear 13 is larger than that of the rear transmission gear 13 so that the front wheels can travel at a higher speed than the rear wheels when the tractor turns. Therefore, vibration noise is large in the spur gear, and therefore the front transmission gear 12 and the front transmission gear 1
Both 4 are composed of helical gears. Further, as a result, thrust acts on the front wheel power take-off shaft 3 before and after the front driven gear 14. Here, when the power is transmitted to the forward side, it acts backward, and when the power is transmitted to the reverse side, it acts forward. Further, when power is transmitted to the bevel pinion shaft 2 without passing through the creep gear shaft 7, the front driven gear 14 (and a component that rotates together with the front driven gear 14) and the creep gear shaft 7 make a large relative rotation.

On the other hand, the rear driven gear 15 is fitted onto the front wheel power take-off shaft 3 via the inner race 20 and the needle bearing 21, and the length of the inner race 20 in the front-rear direction is the fitting portion of the rear driven gear 15. The inner race 20 has a front wheel power take-off shaft 3
Is engaged in the clutch body 17 and the rear driven gear 15 by the thrust from the front driven gear 14.
The friction coefficient between and does not become large.

Further, as shown in detail in FIG. 2, the front wheel power take-off shaft 3 between the front driven gear 14 and the creep gear shaft 7 is provided.
A peripheral groove 22 is formed in the outer peripheral portion, and a half collar 23 (a collar divided into two in the radial direction) is fitted on the peripheral groove 22. This half collar 23 and front driven gear 1
4, a collar 24 and a ring collar 25 are provided so that the thrust from the front driven gear 14 can be received by the half collar 23 via the collar 24 and the ring collar 25. Thrust does not act on.

Between the half collar 23 and the creep gear shaft 7, a separation preventing collar 26 for preventing the half collar 23 from separating from the circumferential groove 22 is fitted. On the outer peripheral side of the rear end portion of the detachment prevention collar 26, a cylindrical fitting portion 27 which is fitted on the half-divided collar 23 is provided in a rearward projecting shape. A small gap 28 (about 0.5 mm) is provided between the front end face and the front end face so that the half collar 23 can reliably receive thrust. The separation prevention collar 26 is in contact with the creep gear shaft 7 via a ring collar 29.

The half collar 23 and the front driven gear 14
A radial ball bearing 30 is fixed on the collar 24 between and. The bearing 30 is inserted into an insertion hole 31 formed in the partition wall 1B of the mission case 1, and a slight gap is provided between the inner surface of the insertion hole 31 and the outer peripheral surface of the bearing 30.
The front wheel power take-off shaft 3 with the bearing 30 only when the
To support. As a result, even if the front wheel power take-off shaft 3 bends, the front wheel power take-off shaft 3 will not be broken from the portion where the circumferential groove 22 is formed.

In the above structure, when assembling the parts on the front wheel power take-off shaft 3, the front wheel power take-off shaft 3 is inserted into the mission case 1 from one end side in the axial direction while each part is taken from the one end side in the axial direction. It will be fitted out. At this time, the half collar 23 is fitted with the parts between the creep gear shaft 7 and the rear driven gear 15 and then the separation preventing collar 26 is fitted into the circumferential groove 22.
The position is shifted further to the front side, and in that state, the half-split collar 23 is fitted onto the circumferential groove 22, and then the separation preventing collar 26 is moved backward to fit the fitting portion 27 to the half-split collar 23. After that, they are supported by the partition walls 1A and 1C via bearings.

In FIGS. 3 and 4, a hydraulic device 32 for raising and lowering the working machine is mounted on the rear portion of the mission case 1. A torsion bar mount 33 is fixed to the rear surface of the case of the hydraulic device 32, and the torsion bar 34 is supported on both sides by the mount 33. One end of the torsion bar 34 is penetrated by the mount 33 and the torsion bar 34. It is non-rotatably fixed via a pin 35. In addition, the top link mount 3 is provided between the support portions of the torsion bar 34.
The front upper part of 6 is externally fitted, and the other end side of the torsion bar 34 is fixed to this mounting base 36 via a pin 37 penetrating both. The pins 35 and 37 are induction hardened, and quenching collars 40 and 41 are tightly fitted in the pin insertion holes 38 and 39 of the mounting bases 33 and 36, respectively.

[0019]

According to the present invention, by forming a circumferential groove on the driven shaft and providing a half collar to be fitted in the circumferential groove, another gear on the driven shaft can be transmitted from the driven gear. The thrust acting toward the gear body is received and does not act on the other transmission gear body from here, and therefore seizure of the contact surface between the other transmission gear body and the collar in contact with this can be prevented.

Also, the peripheral groove is not a half collar,
It is possible to receive the thrust even if the C-shaped circlip is fitted, but it is difficult to assemble the parts to be assembled on the driven shaft unless the collar is inserted at the end for assembly. That is, at the time of assembly, parts such as gears and collars are externally fitted while the driven shaft is inserted into the transmission case from one end side. It is necessary to move the circlip rearward in the inserting direction in order to fit the above-mentioned parts to the outside, which is difficult and time-consuming to assemble. On the other hand, according to the present invention, in particular, the stopper for receiving the thrust is composed of the half-split collar, and the stopper is detachably fitted to the outer periphery of the half-split collar to prevent the half-split collar from coming off the circumferential groove. By adopting a structure in which the collar is externally fitted to the driven shaft, the stopper that receives the thrust can be incorporated at the end, and there is an advantage that the assembly is easy.

[Brief description of drawings]

FIG. 1 is a side sectional view of a rear portion of a mission case.

FIG. 2 is a side sectional view of a main part.

FIG. 3 is a side view of a rear upper portion of a mission case.

FIG. 4 is a sectional view taken along the line AA of FIG.

[Explanation of symbols]

 2 Bevel pinion shaft (transmission shaft) 3 Front wheel power take-off shaft (transmission shaft) 7 Creep gear shaft (other transmission gear body) 12 Transmission gear 14 Driven gear 22 Circumferential groove 23 Half collar 26 Separation prevention collar

Claims (1)

[Claims] 1. A transmission gear (12) is provided on a transmission shaft (2) to which power from an engine is transmitted, and the transmission gear (1)
The driven gear (14) that engages with 2) is rotatably fitted onto the driven shaft (3), and the driven shaft (2) is transferred to the driven shaft (3) through the driven gear (14). The power is transmitted, the transmission gear (12) and the driven gear (14) are constituted by helical gears, and thrust from the driven gear (14) on the driven shaft (3) acts. On the side,
A power transmission device for a vehicle, comprising another transmission gear body (7) which rotates relative to a transmission gear (14), comprising a transmission between the transmission gear (14) and another transmission gear body (7). A peripheral groove (22) is formed on the shaft (3), and a half collar (23) for receiving the thrust from the driven gear (14) is fitted into the peripheral groove (22), and the driven shaft (3). above,
It is characterized in that a separation preventing collar (26) is fitted on the outer periphery of the half-split collar (23) so as to be detachably fitted to prevent the half-split collar (23) from coming off the circumferential groove (22). Vehicle power transmission device.