JPS6233160Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a gear change operating device for operating a gear change device provided on a vehicle such as an agricultural tractor.

Two shift forks are used to shift a gearshift clutch body such as a shift gear in order to operate a multi-stage transmission device with, for example, four gears. Two shift forks are supported by separate fork shafts. The reason for this is that in a structure in which two shift forks are supported by one fork shaft, when one shift fork is moved to any gear shifting position, the other shift fork may unexpectedly shift gears from its neutral position. This is because it is difficult to provide a mechanism to prevent repeated meshing of gears, etc., from occurring when the gears are moved to a different position.

The purpose of this invention is to provide a mechanism for preventing double meshing with a simple structure that allows two shift forks for shifting a single transmission to be supported by one fork shaft. To provide a new speed change operation device in which two shift forks are actually supported by one fork shaft, and the structure is simplified.

Regarding the illustrated embodiment, the configuration of the gear shift operation device according to the invention will be explained. This embodiment is an example in which the invention is implemented as a gear change operation device for a transmission 1 as shown in FIGS. 1 and 2. Pertains to. The transmission 1 is configured as a main transmission for the traveling system disposed between a drive shaft 3 and a main transmission shaft 4 in a transmission case 2 of an agricultural tractor, and the drive shaft 3 is connected to a transmission input shaft 5 for deceleration. They are interlocked and connected via gears 6 and 7, and the main transmission shaft 4 is interlocked and connected in the direction of the driving wheels via a traveling system sub-transmission device (not shown).

In addition to the gear 7 described above, three gears 8, 9, and 10 are fixedly installed on the drive shaft 3, and four gears 11, 12, 13, and 14 are installed on the main transmission shaft 4. When fitted, the gears 7, 8, 9 on the drive shaft 3 and the gears 11, 12, 13 on the main transmission shaft 4 mesh linearly, respectively, and the gear 10 on the drive shaft 3 and the main transmission shaft The upper gear 14 is meshed with the gear 14 on the transmission case 2 through an idler gear 15 which is freely rotatably supported by a support wall 2a provided upright in the middle of the transmission case 2. On the main transmission shaft 4, there is a space between gears 11 and 12 and a gear 1.
Spline cylinders 16 and 17 having spline claws on the inner and outer circumferential surfaces are fixedly installed between 3 and 14, respectively, and shift collars 18 and 19 are fitted onto each spline cylinder 16 and 17 so that they can only slide freely. It is provided. Gear 1 on main transmission shaft 4
The boss portions 1 and 12 have claws 11a and 12a that can engage spline claws on the inner peripheral surface of the shift collar 18.
However, the boss portions of the gears 13 and 14 on the main transmission shaft 4 are formed with pawls 13a and 14a, respectively, which can engage spline pawls on the inner peripheral surface of the shift collar 19.

As described above, the transmission 1 selectively slides and displaces each of the shift collars 18 and 19 described above, and when the spline pawl of the shift collar 18 engages with the pawl 12a, the gear ratio F ₁ of the first forward speed is achieved, and the shift collar 1
When the spline claw 9 is engaged with the claw 13a, it moves forward 2.
When the spline claw of the shift collar ₁₈ is further engaged with the claw 11a, the gear ratio _F3 is for the third forward speed, and when the spline claw of the shift collar 19 is engaged with the claw 14a, the gear ratio is F3 for the third forward speed. Gear ratio R
The drive shaft 3 and the main transmission shaft 4 are respectively selectively interlocked and connected.

Transmission device 1 equipped with four gear stages as described above
In contrast, the shift operation mechanism of the transmission 1 has only one fork that is fixedly supported by the transmission case 2 and parallel to the main shift shaft 4, as shown in FIG. A shaft 20 is provided. The fork shaft 20 has two shift forks 21 and 22 that are mutually connected, a shift fork 21 engaged with the shift collar 18 and another shift fork 22 engaged with the shift collar 19. They are supported so as to be slidably displaceable at appropriate intervals. As shown in FIG. 5, two operating shafts 23 and 24 are supported on one side wall of the mission case 2 and are rotatably provided in parallel with each other, as shown in FIG. At the inner end of each operating shaft 23, 24, there is an operating arm 25, 2 that engages each shift fork 21, 22.
6, and levers 27 and 28 are fixed to the outer ends of each operating shaft 23 and 24, respectively.

As a result of the above, the lever 27 is rotated and the operating shaft 2 is rotated.
3 and the shift fork 21 via the actuation arm 25
By slidingly displacing the shift collar 18 on the forkshaft 20, sliding displacement of the shift collar 18 can be obtained, and by rotationally displacing the lever 28, the operating shaft 24
It is also possible to obtain the sliding displacement of the shift collar 19 by slidingly displacing the shift fork 22 on the fork shaft 20 via the operating arm 26, but both shift forks 2
1 and 22 are simultaneously displaced to the shift action position, resulting in so-called multiple meshing, that is, the shift collar 18 is slidably displaced by the shift fork 21.
is simultaneously moved to a position where it meshes with the pawl 11a or 12a, and the shift collar 19, which is slid by the shift fork 22, is simultaneously displaced to a position where it meshes with the pawl 13a or 14a, resulting in two-row gear shifting. In order to prevent a situation in which the gear trains are operated at the same time, the following mechanism is provided.

That is, as shown in FIGS. 2 and 3, the fork shaft 20 has two shift forks 21 and 22.
A through hole 29 is formed along the direction transverse to the fork shaft 20, and as shown in FIGS. The extending portions 21a and 22a located opposite to each other are formed so that the width along the circumferential direction of the fork shaft 20 becomes smaller toward the extending end thereof. Each shift fork 21, 22 has a slot 30, 31 on the inner surface of the extension portion 21a, 22a, and each shift fork 21, 22 has a neutral position shown in FIG. 3, that is, each shift collar 18, 19. Claw 1 shown in Figure 1
1a, 12a or pawls 13a, 14a, when the respective slots 30, 31 are in the through hole 2 of the fork shaft 20.
9 and are formed so as to face each other.

The above-mentioned through hole 2 formed in the fork shaft 20
A pin 32 is slidably fitted in 9, and the length of this pin 32 is set as follows. That is, FIG. 6a shows a state in which the shift fork 21 has been moved to the third forward speed position _F3 , that is, a position where the shift collar 18 is engaged with the pawl 11a, and FIG. 6b shows a state in which the shift fork 22 is moved forward. 2nd gear position
F ₂ , that is, the state in which the shift collar 19 is moved to the position where it is to be engaged with the pawl 13a, is shown in each figure, but as shown in FIG. 29, each shift fork 21, 22 is allowed to slide on the fork shaft 20, whereas as can be understood from FIGS. 6a and 6b, one shift fork 21 or When the slot 30 or 31 of the shift fork 22 is removed from the position of the through hole 29, the pin 32 is pushed by the inner surface of the extension part 21a or 22 of the shift fork 21 or 22 of the other shift fork 2.
The length of the pin 32 is set so that it protrudes into the slot 31 or 30 of the other shift fork 22 or 21, making sliding displacement of the other shift fork 22 or 21 impossible. Therefore, when the shift fork ₂₁ is moved from the neutral state illustrated in _FIG . Furthermore, when the shift fork 22 is moved from the neutral state shown in _FIG . Thus, the above-mentioned double meshing is prevented.

Six annular grooves 33F ₃ , 33N, 33F ₁ , 33F ₂ , 33 are provided on the circumferential surface of the fork shaft 20 in correspondence with the respective positions taken by the shift forks 21 and 22.
N', 33R are formed, and each shift fork 21, 22 has a spring 34, 35 and an annular groove 33F ₃ , 33N or 3
3F ₁ and balls 36 and 37 that enter 33F ₂ , 33N' or 33R are housed inside to form a conventional detent mechanism.

Although not shown, the levers 27 and 28 shown in FIG. 5 are connected by a link to a single gear shift lever supported rotatably along one direction and the other direction orthogonal to each other, By rotating the gear shift lever in one direction, either lever 2
By engaging the gear shift lever with the link connected to 7 or 28, and then rotating the same gear shift lever in the other direction, the lever 27 or 28 can be rotated, and the desired gear shift can be performed. It is something that can be achieved.

As is clear from the above description, the gear shift operation device of this invention is capable of slidingly displacing two shift forks 21 and 22 into one fork shaft 20 for shifting gears of a single transmission device 1. A through hole 29 is formed in the fork shaft 20 along a direction across the fork shaft 20 between the two shift forks 21 and 22, and the fork shaft 20 extends in the direction of the through hole 29. The extension parts 2 are located opposite to each other across the
Both shift forks 21, 1a and 22a described above,
22, and groove holes 30, 31 are formed in each shift fork 21, 22 on the inner surface of the extension parts 21a, 22a, facing the through hole 29 in the neutral position of each shift fork 21, 22. In addition, a pin 32 that is slidably fitted into the through hole 29 is provided, and when the slots 30 and 31 of both the shift forks 21 and 22 both face the through hole 29, the pin 32 is inserted into the through hole 29. Sliding displacement of the shift forks 21 and 22 is allowed, but when the slot 30 or 31 of one of the shift forks 21 or 22 is removed from the position of the through hole 29, the extension of the one shift fork 21 or 22 is allowed. The protruding portion 21a or 22a is pushed by the inner surface and plunges into the slot 30 or 31 of the other shift fork 22 or 21, making sliding displacement of the other shift fork 22 or 21 impossible. This structure is characterized by being formed into a pin having a set length, and has the following advantages.

That is, the speed change operation device of this invention is based on the above-described configuration, and has two shift forks 21 and 22.
When one of the shift forks 21 or 22 is moved from the neutral position to the shift operating position, the other shift fork 22 or 21 is restrained in the neutral position so that it cannot slide. Therefore, the system is designed to prevent both shift forks 21 and 22 from being moved to the shift action position at the same time and causing the above-mentioned repeated meshing. The mechanism includes a short pin 32 fitted into a through hole 29 drilled in the fork shaft 20 and each shift fork 21, 2.
The mechanism is said to have an extremely simple structure, consisting of extension parts 21a and 22a provided in the inner surface of the extension part 2 and having slots 30 and 31 formed on the inner surface. It is assumed that no inconvenience will occur even if two shift forks 21 and 22 are supported by one fork shaft 20, and in fact
The proposed device, which has only one fork shaft 20 for each of the shift forks 21 and 22, has a simpler structure and is less expensive than the conventional device, which has two fork shafts as explained at the beginning. It is said that it will be produced in

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional side view of the main parts of an agricultural tractor equipped with an embodiment of this invention, Fig. 2 is a longitudinal sectional front view of the main parts of the same tractor, and Fig. 3 is a longitudinal sectional side view of the main parts of the same embodiment. Fig. 4 is a plan view of only the main parts of the same embodiment, Fig. 5 is a side view of a part of the same embodiment, and Figs. 6 a and b are longitudinal cross-sectional side views of only the main parts of the same embodiment. It is a diagram. 1... Transmission device, 18, 19... Shift collar, 20... Folkshaft, 21, 22...
Shift fork, 21a, 22a... extension part, 2
3, 24... Operating shaft, 25, 26... Operating arm, 29... Through hole, 30, 31... Slot hole, 32
……pin.

Claims (1)

[Scope of utility model registration request] Two shift forks for operating a single transmission are slidably supported by one fork shaft, and the fork shaft is moved across the fork shaft between the two shift forks. While forming a through hole along the direction,
Extension portions extending in the direction of the through hole and positioned opposite to each other across the fork shaft are provided on both of the shift forks described above, and each shift fork is provided with an extension portion on the inner surface of the extension portion, and a neutral portion of each shift fork is provided on the inner surface of the extension portion. A slotted hole is formed at a position facing the through hole, and a pin is provided to slidably fit into the through hole, and the pin is inserted so that the slotted holes of both of the shift forks both face the through hole. In this state, sliding displacement of each shift fork is allowed, but when the slot of one shift fork is removed from the above-mentioned through-hole position, it is pushed by the inner surface of the extension of the other shift fork, and the above of the other shift fork is pushed. A speed change operating device characterized in that it is formed in a pin having a length set so as to penetrate into a slot and disable sliding displacement of the other shift fork.