JPS61171961A - Gear creak prevention mechanism of speed change gear - Google Patents

Abstract

PURPOSE:To prevent gear creak surely by moving a forward step fork rod until action of a synchronous mechanism is finished when a retreat step fork rod is moved to the retreat step side by a shifter having a bracket engaging arm. CONSTITUTION:A shifter 14 is fixed to a striking rod 10 and engaged with a first bracket 16. And a second fork rod 18 is driven to be moved by a bracket engaging arm 14a to change speed of a speed change gear through a synchronous mechanism by a shift fork. As a reverse idler gear is stopped its rotation and engagement with the reverse counter gear is made smoothly during synchronous action, gear creak can surely be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a transmission gear noise prevention mechanism that prevents gear noise that tends to occur when a change lever of a vehicle transmission is shifted to reverse gear.

(Prior art) Conventionally, manual transmissions do not have a synchronizer for the reverse gear, so when shifting the change lever to the reverse gear position, an unpleasant gear noise occurs. was there. Furthermore, in order to prevent this gear noise, proposals have been made in the past to utilize synchronizers for forward gears (for example, Japanese Patent Application Laid-open No. 137747/1982, Japanese Patent Publication No. 14655/1983, Patent No. 3545295
issue).

(Problem to be Solved by the Invention) However, in all of the conventional proposals for preventing gear noise when shifting to reverse gear using a synchronizer for forward gear, the synchronizer for forward gear is operated. Since the structure was such that the operating force to shift the synchronizer is proportional to the repulsive force of the spring supporting the pin, the operating force applied to the synchronizer changes depending on the speed of the shift operation of the change lever. for example,
When quickly shifting to reverse gear with strong force, the operating force necessary for the synchronizer operation cannot be applied, and the rotation of the input side countershaft is not reduced, resulting in a problem in which gear noise cannot be reliably prevented. . On the other hand, when the shift operation is performed slowly, the change lever becomes heavier than necessary, resulting in a problem that requires a large operating force.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to reliably prevent gear noise during a reverse gear shift with a constant operation stroke, regardless of the shift operation speed of the change lever.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the gear noise prevention mechanism for a transmission according to the present invention has a shifter that is driven to each gear position by a shift operation of a change lever and has a bracket engagement arm. a first bracket fixed to the reverse gear fork rod and engageable with the bracket engaging arm; and a first bracket fixed to the forward gear fork rod for shifting the transmission to the forward gear via a synchronization mechanism. a second member engageable with the bracket engagement arm;
a bracket; a contact arm provided on the shifter;
provided on the second bracket, the bracket engaging arm contacts the abutting arm portion when the bracket engaging arm engages with the first bracket, and the forward gear fork rond is in a predetermined position together with the reverse gear fork rod. and a contact member whose contact is released when the contact member is moved a distance.

(Function) By shifting the change lever, the shifter is driven to each gear position, and the bracket engaging arm of the shifter is connected to the second bracket fixed to each forward gear fork rod or the reverse gear fork rod. The first bracket is selectively engaged with a first bracket fixed to the first bracket to perform a gear shifting operation of the transmission.

When the bracket retaining arm engages with the second bracket and drives the forward gear fork rod, this four, OyF
! Through the synchronization mechanism, the mechanical transmission is shifted to the required forward gear. When the bracket engaging arm engages with the first bracket and drives the reverse gear fork rod toward the reverse gear, the abutting arm integrally provided on the shifter engages with the abutting arm supported by the second bracket. In order to come into contact with the contact member, the forward gear fork rod moves together with the reverse gear fork loft via the contact arm, the contact member, and the second bracket. At this time, when the forward gear fork rod moves a predetermined distance, each gear supported by the countershaft of the transmission is braked and stopped by the synchronizing action of the synchronizing mechanism, and the contact arm of the shifter and the second bracket side The contact with the contact member is released. After this, only the reverse gear fork rod continues to move by the shifter's bracket engagement arm, and the reverse idler gear, which has stopped rotating, is quietly engaged with the reverse gear gear, which has also stopped rotating. This makes it possible to reliably prevent gear noise. .

(Example) Hereinafter, an example of the present invention will be described based on the drawings. 1 to 3 are diagrams showing a mechanism for preventing gear noise of a transmission according to an embodiment of the present invention.

In FIGS. 1 and 2, 10 is a strike-in rod that slides and rotates by shifting a change lever (not shown), and this strike-in rod 10 has a pin 1.
2, the shifter 14 is integrally fixed. A bracket engaging arm 1 is located below the right end of the shifter 14 in FIG.
4a, and an abutment arm 14b is formed at the lower left end in the figure. The tip of the bracket engaging arm 14a of the shifter 14 is connected to the first bracket 16.
The first bracket 16 is engaged with the recess 16a of the first bracket 16
is connected and fixed to one end of the second fork rod (fork rod for forward gear) 18 shown in FIG. ing. Contact arm 1 of shifter 14
The tip of the cam lever 4b is in contact with the contact portion 20a of the cam lever (contact member) 20, and this cam lever 20 is in contact with the pin 22.
It is rotatably supported by the second bracket U via the bracket U, and is constantly urged by a spring to rotate in the counterclockwise direction in FIG. 2nd bracket, G2
4 is connected and fixed to one end of the second fork 0.7 door 18 via a pin 2B, and this second bracket 24 also has a bracket engaging arm 14a of the shifter 14 at the same position as the first bracket 6. A recess 24a is formed in which the tip engages.

A third bracket 30 having a recess 30a similar to the first bracket 16 and the second bracket 24.
The third bracket 30 is connected and fixed to one end of a third fork rod (not shown) disposed between the second fork rod 18 and the first fore rod. By shifting the change lever, the bracket engaging arm 14a of the shifter 14 is selectively connected to the recesses 16a, S24a, and 30a of the first bracket 16, the second bracket U, and the third bracket (part) via the striking loft 10. engage with. Second
The fork rond 18 is driven and moved by the bracket engaging arm 14a of the shifter 14 in the leftward or rightward direction in FIG. is shifted to the first or second gear. Third bracket 30
The third fork rod to which is fixed is similarly driven and moved by the bracket engaging arm 14a in the leftward or rightward direction in the figure, thereby shifting the transmission to the third or fourth gear through the synchronization mechanism. let The first fork rod to which the first bracket 16 is fixed is similarly driven and moved in the left direction in the figure by the bracket engaging arm 14a, thereby shifting the transmission to the reverse gear without using a synchronization mechanism. ing.

Next, the effect will be explained. By shifting the change lever, the bracket engaging arm 14a of the shifter 14 is selectively connected to the recesses 24a, 30a, and 16a of the second bracket 24, third bracket 30, and first bracket 16 via the striking rod 10. is engaged to shift the transmission to the first to fourth gears or the reverse gear as described above. As shown in FIG. 2, the placket engagement @14a of the shifter 14 engages with the recess 16a of the first bracket I6! When the shifter 14 is in the aligned position, the abutment arm 14b of the shifter 14 abuts the abutment part 20a of the cam lever 20, as shown in FIG. Therefore, when the bracket engaging arm 14a moves the first fork rond to the reverse gear side via the first bracket 1-16, the second Move Forkrond 18 together.

Since the abutting arm 14b moves by pushing the abutting part 20a without rotating around the axis of the striking rod 10, the shifter 14 rotates by a predetermined angle θ in the clockwise direction in the drawing, as shown in FIG. Then, the second bracket 24
moves a predetermined distance l, the abutting arm 14b and the abutting part 20
The contact with a is released. The second bracket 24, that is, the second fork rond 18 is moved at a predetermined distance like this! When moving, the synchronization mechanism (not shown) becomes balk-like (ends the synchronization action).
The countershaft of the transmission, which had been rotating due to inertia, synchronized with the output shaft (main shaft) of the transmission, which had stopped rotating due to road resistance from the wheels.
A braking force is applied to the countershaft and its rotation is stopped. After this, the second fork rod 18 stops and only the first fork rod continues to move, but at this time, since the reverse idler gear supported by the reverse countershaft has also stopped its rotation, the first fork rod Since the reverse idler gear and the reverse counter gear engage with each other quietly and smoothly due to movement, gear noise can be reliably prevented. Further, the synchronizing action of the synchronizing mechanism depends only on the movement of the second fork rond 18 by a predetermined distance l, and is not affected by its moving speed, and its operating force is always constant. Contact arm portion 14b and contact portion 2
After the contact with 0a is released, the second fork rond 18
is returned to its original neutral position as shown in FIG. 1 by means of a suitable restoring means such as a spring (not shown). When the bracket engagement arm 14a returns to the original neutral position after the shift to the reverse gear by the first fork rond, the tip of the contact arm 14b contacts the upper surface of the contact portion 20a during the process. However, at this time, the cam lever 20 rotates in the clockwise direction in FIG. It can be reliably returned to the original neutral position as shown in the figure. After the abutment arm 14b has passed in this manner, the cam lever 20 is returned to its original position as shown in FIG. 1 by the biasing force of the spring.

In the embodiment, a case where the number of gears is the fourth gear has been described, but a fifth gear may be provided on the opposite side to the reverse gear.

(Effects of the Invention) As explained above, according to the present invention, when the shifter moves the reverse gear fork rod to the reverse gear side, the synchronizing action of the synchronization mechanism also ends for the forward gear fork rod. By moving the gears together until the shift lever is shifted, it is possible to reliably prevent gear noise during a reverse gear shift with a constant operation stroke regardless of the shift operation speed of the change lever.

[Brief explanation of the drawing]

The drawings show a gear noise prevention mechanism for a transmission according to an embodiment of the present invention, and FIG. 1 is a side view thereof, FIG. 2 is a sectional view taken along the line nn in FIG. 1, and FIG. is a side view showing its action. 14------Shifter, 14a---Bracket engaging arm, 14b-
-1.-Abutting arm part, 16--1 first bracket, 18--2nd fork rod (forward gear fork rod), 20------cam lever (abutting member) , 24-・-
-Second bracket.

Claims (1)

[Claims] A shifter that is driven to each gear position by a shift operation of a change lever and has a bracket engaging arm, a first bracket that is fixed to a reverse gear fork rod and can be engaged with the bracket engaging arm, and a synchronizing mechanism. a second bracket that is fixed to a forward gear fork rod that shifts the transmission to a forward gear and is engageable with the bracket engagement arm;
an abutment arm provided on the shifter; and an abutment arm provided on the second bracket that abuts the abutment arm when the bracket engagement arm engages with the first bracket, A gear noise prevention mechanism for a transmission, comprising: a contact member that releases the contact when a fork rod moves a predetermined distance together with the reverse gear fork rod.