JPH0755407Y2 - Shift fork drop prevention jaw - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a shift fork dropout preventing jaw for improving the assembling property of a tubular transmission case or the like.

<Prior Art> In large vehicles such as trucks and buses, generally, a transmission gear unit is housed in a transmission case body, which is an upper opening, and control-related parts such as a shift fork and a shift rail are held on the upper surface thereof. The method of placing the lower case made of aluminum alloy was adopted. However, this method has a drawback in that noise associated with gear meshing is likely to be transmitted to the outside from the lower case or the like, and the rigidity tends to be insufficient. In addition, since the number of tightening bolts is large and it is difficult to form a transmission gear unit, a shift fork, or the like into a sub-assembly, the number of assembling steps is large.

Therefore, there has been proposed a so-called tubular transmission case in which a transmission case main body and an upper case are integrated as shown in FIG. In the illustrated example, the gear unit 3 including the main shaft 1, the counter shaft 2 and the like, the shift fork 4, the shift rail 5 and the like are housed in a cast iron integral transmission case 6 in which the forward gear is 5 forwards and the reverse gear is 1 stage.

In the figure, 7 is an upper case for accommodating the gear shift sliding lever 8 and the like.
It is mounted directly on the upper surface of. The front surface of the transmission case 6 is closed by a clutch housing 9. Therefore, when assembling,
As shown in the figure, a method is adopted in which the gear unit 3, the shift fork 4 and the shift rail 5 are used as a sub-assembly, and the transmission case 6 is inserted from the front side.

<Problems to be Solved by the Invention> Normally, in the main shaft 1, the reverse gear 10 is formed in front of the first gear 11 due to processing problems and the like. The movement of the shift rail 5 needs to be inverted and transmitted due to a problem in the shift pattern. In the above-mentioned transmission, this is performed by using the swing type shift fork 12 instead of the general reversing lever and the slide type shift fork.

As shown in FIG. 6 (enlarged sectional view taken along the line AA in FIG. 4), the swing type shift fork 12 has the upper end 12a fitted into the notch 13 formed in the shift rail 5, and the transmission case 6 An inversion pin 14 press-fitted to the left and right of the rotatably supports the center in the up-down direction so as to be rotatable. Therefore,
If the shift rail 5 moves forward, the swing type shift fork 12
On the contrary, the lower end of moves backward.

By the way, in the assembly shown in FIG. 5, the reversing pin 14 is inserted into the swing type shift fork 12 after the gear unit 3 and the like, which are sub-assembled in process, are inserted into the transmission case 6. . However, until the reversing pin 14 is inserted, the swing type shift fork
Since 12 moves relatively freely, the upper end 12a often comes off from the notch 13, that is, falls off, as shown in FIGS. 6 and 7 (viewed by arrow B in FIG. 6). Has happened. As a result, when the reversing pin 14 is inserted, the hole position may be displaced, which may make assembly difficult.

<Means for Solving the Problem> In order to solve this problem, therefore, in the present invention, both side surfaces are rotatably supported by reversing pins while being engaged and driven by a shift rail. A jaw for preventing the shift fork from falling off from the shift rail, which proposes a jaw for preventing shift fork drop-off, which is characterized in that the rocking type shift fork is surrounded by the shift rail. Is.

<Operation> Since the swing type shift fork is fixed in the state of being engaged with the shift rail by the shift fork dropout preventing jaw, the assembly is smoothly performed.

<Embodiment> An embodiment of the present invention will be specifically described with reference to the drawings. In the description of the embodiments, the same members as those in the above-described conventional example are designated by the same reference numerals, and the duplicated description will be omitted.

FIG. 1 shows a cross-sectional view of a tubular transmission equipped with a shift fork dropout prevention jaw according to the present invention, FIG. 2 shows a view taken along arrow C in FIG. 1, and FIG. 3 shows a shift fork dropout. As shown in FIG. 1 and FIG. 2, which are perspective views of the prevention jaw, in the transmission according to the present embodiment, the shift rail 5 adjacent to the shift rail 5 engaged with the swing type shift fork 12 is adjacent to the shift rail 5. A shift fork dropout preventing jaw 15 that surrounds the upper end portion 12a of the swingable shift fork 12 is attached between and. As shown in FIG. 3, the shift fork slip-out preventing jaw 15 has a substantially ∝-shaped outer shape, and includes notches 15a into which the upper end 12a of the swing-type shift fork 12 is fitted, and the shift rail 5 respectively. 15b and semicircle 1 where
Have 5c and. Therefore, the swing type shift fork
The upper end 12a of 12 is fixed at a predetermined position, and the shift fork dropout preventing jaw 15 itself does not drop off during assembly.

In the present embodiment, since the shift fork dropout preventing jaw 15 is used to position the swing type shift fork 12 at the time of assembling, the transmission can be assembled smoothly.

Although the description of the specific embodiment is completed above, the present invention is not limited to this embodiment. For example, in the above-described embodiment, the shift fork dropout preventing jaw 15 is adjacent to the shift rail 5.
Although it is also fitted to the shift rail 5, it may be fitted only to the shift rail 5 with which the swingable shift fork 12 is engaged.

<Effect of the Invention> According to the present invention, the swing fork is prevented from falling off from the shift rail by surrounding the swingable shift fork with the shift rail by the shift fork fall prevention jaw. There is an effect such that the assembly of can be performed smoothly.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a tubular transmission equipped with a shift fork dropout prevention jaw according to the present invention, FIG. 2 is a view in the direction of arrow C in FIG. 1, and FIG. 3 is a shift fork dropout prevention. FIG. 3 is a perspective view of a simple jaw. 4 is a longitudinal sectional view of the tubular transmission, FIG. 5 is a perspective view showing the assembling process thereof, and FIG. 6 is A in FIG.
FIG. 7 is a sectional view taken along line A-A, and FIG. 7 is a view taken in the direction of arrow B in FIG. In the drawing, 3 is a gear assembly, 4 is a shift fork, 5 is a shift rail, 6 is a transmission case, 12 is an oscillating shift fork, 13 is a notch, 14 is a reversing pin, and 15 is a shift fork fallout prevention jaw. Is.

Claims (1)

[Scope of utility model registration request] 1. A jaw for rotatably supporting both side surfaces by reversing pins, while preventing a swing type shift fork engaged and driven by a shift rail from falling off from the shift rail. A jaw for preventing the shift fork from falling, characterized in that the swing type shift fork is surrounded by the shift rail.