JPH035719Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The invention applies braking force to the shaft rotating within the gear transmission during idling, and releases this braking force when the transmission is shifted. The present invention relates to an abnormal noise prevention device for a gear transmission equipped with a braking force release mechanism.

(Prior Art) This type of abnormal noise prevention device has already been provided by the present applicant in various configurations (for example, see Japanese Utility Model Application No. 60-59853). To give an overview of this prior technology, in a transmission equipped with a synchromesh device on the shaft rotating in a neutral state, a shape memory alloy is used that deforms when the oil temperature inside the transmission case exceeds a certain value. The action of the spring (hereinafter referred to as "SMEA spring") causes the shift fork of the synchronized mesh device to slide in the shifting direction, and the synchronized rotation of the synchronized mesh device causes the rotating shaft to shift. It is designed to provide braking force to the

When the transmission is operated to any shift state, the loss of engine driving force is avoided and
In addition, in order to improve the durability of the transmission, it is provided with a braking force release mechanism that functions to release the braking force on the shaft. This braking force release mechanism operates when a fork shaft for a shift fork that is different from the above-mentioned shift fork is shifted.
The shift fork of the synchronized mesh device
Regardless of the function of the SMEA spring, it acts to push it back to the neutral position. That is, the operating direction of the forkshaft to be shifted is
The shift operation of the forkshaft is reversed directly when the acting direction is opposite to that of the SMEA spring, or through a reversing arm that rotates in conjunction with the acting direction when the acting direction is the same as that of the SMEA spring. The shift fork is pushed back to the neutral position to release the above braking force.

(Problems to be Solved by the Invention) In the above configuration, the release stroke of the brake force release mechanism may become excessive due to variations in the dimensional tolerances of each member constituting the brake force release mechanism. Particularly when the reversing arm is a component of the release action transmission path, variations in dimensional tolerances and dimensional errors are likely to occur due to its configuration. This excessive stroke of the release operation not only applies unnecessary loads to each component of the braking force release mechanism, but also causes problems such as a shift stopper occurring in the action transmission path of the release mechanism.

In addition, it may be possible to take into account variations in the dimensional tolerances of each component of the above-mentioned braking force release mechanism and take precautions in advance so that the release action does not have an excessive stroke, but this may conversely result in an insufficient release action stroke. In this case, even when the braking force is released, the synchronized mesh device cannot return to the proper neutral position, and the synchronized mesh device constantly generates friction torque, which significantly reduces its durability. Become. Therefore, it is actually extremely difficult to set the dimensional tolerances of the various constituent members so that the release stroke of the braking force release mechanism is just right.

(Means for Solving the Problems) The present invention, as shown in FIG.
An elastic body 28 is incorporated which exerts a larger reaction force against the force of the SMEA spring 20 acting on the shift fork 14.

(Function) According to the above configuration, the excessive stroke of the braking force release mechanism 22 can be absorbed by the elastic deformation of the elastic body 28 incorporated in the release action transmission path. Therefore, it is possible to avoid unnecessary loads from being applied to the various constituent members of the braking force release mechanism 22, and it is also possible to prevent a shift stopper from occurring in the braking force release mechanism 22.

(Example) Hereinafter, an example of the present invention will be specifically described based on the drawings.

In FIG. 1, which is a cross-sectional view of a part of the inside of the gear transmission, and FIG. 2, which is a cross-sectional view taken along the line - in FIG. A foot 3 is rotatably supported.
The countershaft 2 rotates in response to torque transmission from an engine (not shown) even when the transmission is in neutral and idling with a clutch (not shown) engaged. This countershaft 2
A large-diameter gear 4 for the 5th gear rotatably supported on the axis of the output shaft 3 is constantly meshed with a small-diameter gear 5 for the 5th gear supported on the axis of the output shaft 3 so as to rotate together with the shaft 3. .
Further, a 5th synchronizing mesh device (hereinafter simply referred to as a "synchronizing device") 6 is also disposed adjacent to the 5th large diameter gear 4 on the axis of the countershaft 2.

As is well known, the synchronizer 6 is supported such that its clutch hub 7 can rotate integrally with the countershaft 2.
A hub sleeve 8 is spline-slidingly fitted to the outer periphery of the hub sleeve 8 so as to be slidable in the axial direction. Further, a 5th shift fork 14 having a shape shown in FIG. 2 is engaged with a fork engaging groove 8a formed on the outer periphery of the hub sleeve 8. Therefore, if a shift operation to 5th gear is performed, the hub sleeve 8 of the synchronizer 6 will be shifted from the position shown in FIG. 1 to the large diameter gear 4 through the shift fork 14. A slide operation is performed towards the target. Along with this, friction occurs between the side of the member (synchronizer ring, etc.) that rotates together with the clutch hub 7, hub sleeve 8, etc., and the side of the large diameter gear 4 that is constantly meshed with the small diameter gear 5 on the output shaft 3. Torque is generated, and based on this torque, a rotational synchronization effect is achieved between the countershaft 2 and the large-diameter gear 4 on the shaft. When the engine is idling, a braking force is applied to the countershaft 2, which is rotating in response to torque transmission from the engine, by the rotation synchronization effect as described above.

Now, as is clear from FIG. 2 and FIG. 3, which is a cross-sectional view taken along the line - in FIG.
The forkshaft 12 for 5th-reverse and the forkshaft 13 for 5th-reverse are parallel to each other and are arranged so as to slide in the axial direction by shift operations for each. As is clear from FIG. 3, on the shaft of the 5th reverse fork shaft 13, the boss portion 14a of the 5th shift fork 14 is connected via a flanged bush 15.
are assembled so as to slide relatively in the axial direction. A normal coil pull 19 is assembled between the flange of the flanged bush 15 and the boss 14a of the shift fork 14.
Also, the flange bushing 15 on the right side of Fig. 3
A flanged sleeve 16 is fixed to the outer periphery of the flanged sleeve 16, and a spring 20 manufactured by SMEA is assembled between the flanged portion of the flanged sleeve 16 and the boss portion 14a of the shift fork 14.

The SMEA spring 20 described above is in the most contracted state shown in the drawings unless the temperature of the lubricating oil in the transmission case 1 reaches a preset value. In this state, the shift fork 14 is held at the neutral position shown in the figure by the elasticity of the normal coil spring 19. Therefore,
When the temperature of the lubricating oil rises and exceeds a predetermined set value, the SMEA spring 20 described above stretches, and the shift fork 14 overcomes the elasticity of the normal coil spring 19 and shifts to 5th gear. It will slide to. As a result, the synchronizer 6 is operated in the shift direction,
Due to the rotation synchronization effect, a braking force is applied to the countershaft 2 as described above.

Next, in order to release the braking force applied to the countershaft 2, that is, SMEA
The release mechanism 22 for pushing the shift fork 14, which has been moved in the shift direction by the spring 20, back to the neutral position will be explained. First, among the operation transmission paths of this braking force release mechanism 22,
5th - The other forkshafts 11 and 12 except the forkshaft 13 for reverse shift to 2nd (2nd speed) or 4th gear, which is opposite to the shift direction to 5th (5th speed).
Regarding the movement transmission path when a shift operation is performed in the shift direction (rightward in FIG. 3) to (fourth speed), the overhanging portion 23 formed on the fifth shift fork 14 is connected to each fork shaft 11 ,1
The shift fork 14 is pushed back to its neutral position by receiving a pressing force when the shift fork 14 is shifted to the right in FIG. On the other hand, the forkshaft 11 for 1st-2nd and the forkshaft 12 for 3rd-4th shift in the same direction as the shift direction to 5th (5th gear).
The structure of the release operation transmission path when a shift operation is performed in the direction of shifting to 1st (1st speed) or 3rd (3rd speed) (to the left in Figure 3) is based on the shafts of these forkshafts 11 and 12. The release heads 24 are each fixed on the top with bolts 25, and one end of a reversing arm 26 formed in a curved shape is rotated with a pin 27 relative to each release head 24 as shown in FIG. Installed as possible. As a result, fork shaft 1 for 1st-2nd
When either of the fork shafts 12 for 1 and 3rs-4th is shifted to the left in FIG. is pressed against a stationary part of the shift fork 14 and rotates, and the movement in the shift direction at that time is reversed and transmitted to the shift fork 14,
In this case as well, the shift fork 14 is pushed back to the neutral position.

Now, the reversing arm 2 is a component of one of the motion transmission paths in the braking force release mechanism 22.
In this embodiment, the retainer 21 of the ball bearing 17 that pivotally supports the output shaft 3 is used as the stationary portion that the rear surface 26a of the output shaft 3 comes into contact with (see FIG. 1). The portion of the retainer 21 that contacts the back surface 26a of the reversing arm 26 is configured as an elastic body 28 that is slightly lifted from the inner wall surface of the transmission case 1 and has a spring force. In other words, this retainer 21
The elastic body 28, which is formed by a part of the reversing arm 26, exerts a spring force that opposes the contact force of the reversing arm 26. The spring force of the elastic body 28 that acts on the shift fork 14 through the reversing arm 26 is set to be larger than the force of the SMEA spring 20 that also acts on the shift fork 14.

In the above configuration, if the oil temperature in the transmission case 1 rises above a certain value,
The SMEA spring 20 stretches, thereby pushing the shift fork 14 with a constant stroke in the direction of shifting to 5th gear, as described above. As a result, the synchronizer 6 performs a rotational synchronization effect, and a braking force is applied to the countershaft 2, which is rotating even during idling. Further, when the oil temperature in the transmission case 1 drops to a predetermined value or less, the SMEA spring 20 contracts to the original state shown in the drawing, or if the spring 20 has a one-way characteristic, The pressing load will be reduced. As a result, shift fork 14
is pushed back to the neutral position by the normal coil spring 19, and the synchronizer 6 is naturally returned to the neutral position, thereby releasing the braking force on the countershaft 2. As a result, when the temperature of the lubricating oil in the transmission case 1 is low and its viscous resistance is large, the braking force applied to the countershaft 2 by the synchronizer 6 is released and the torque transmission efficiency of the transmission, shift feeling, and synchronizer are improved. This avoids situations that would have a negative impact on the durability of 6.

Now, let's talk about the action of the braking force release mechanism 22 when each shift operation is performed in a state where the oil temperature in the transmission case 1 is above a certain value and the above-mentioned braking force is applied to the countershaft 2. explain. First, either the 1st-2nd forkshaft 11 or the 3rd-4th forkshaft 12 is moved toward the right in Figure 3 (2nd or 4th
When the shift operation is performed in the shift direction), as described above, the end of this fork shaft 11 or 12 comes into contact with the overhanging portion 23 of the shift fork 14, causing the shift fork 14 to
Push it back to the neutral position against the elasticity of the SMEA spring 20. As a result, the synchronizer 6 is also pushed back to the neutral position, and the braking force on the countershaft 2 is released.

Also, when either the 1st-2nd forkshaft 11 or the 3rd-4th forkshaft 12 is shifted to the left in Fig. 3,
Along with this, the pin 27, which is the rotation fulcrum of the reversing arm 26, moves in the same direction together with the shift fork 11 or 12, so the reversing arm 2
The back surface 26a of the retainer 21 is strongly pressed against the elastic body 28 formed in a part of the retainer 21 as described above. As a result, the elastic body 28 is slightly bent from the state shown by the imaginary line in FIG. 4 to the state shown by the solid line, but the reversing arm 26 is
6a is supported by the elastic body 28 and rotates about the pin 27 from the state shown by the imaginary line in FIG. push. At this time, since the elastic body 28 is set to have a larger spring force than the SMEA spring 20,
The reversing arm 26 moves the shift fork 14 to SMEA
It rotates against the elasticity of the spring 20 until it is pushed back to the neutral position. As a result, the synchronizer 6 is returned to the neutral position and the braking force on the countershaft 2 is released, as in the case described above.

Here, the above 1st-2nd fork shaft 11
Alternatively, the movement stroke (release operation stroke) of the reversing arm 26 accompanying the shift operation of the 3rd-4th fork shaft 12 is the same as that of the reversing arm 26.
If the size is excessive due to variations in manufacturing dimensional tolerances or assembly dimensional tolerances, the reversing arm 26 rotates as shown by the solid line in FIG.
After pushing the shift fork 14 back to the neutral position,
Furthermore, a force acts to move the reversing arm 26 further downward in FIG. 4. In this case, an elastic body 28 formed using a part of the retainer 21
However, as shown in FIG. 5, it is elastically deformed until it comes into contact with the inner surface of the transmission case 1, absorbing the excessive stroke at this time. As a result, due to the excessive stroke of the braking force releasing operation, the braking force releasing mechanism 2
It is possible to avoid unnecessary loads from being applied to the reversing arm 26 etc. that constitute the reversing arm 26, etc.
The reversing arm 26 acts as a shift stopper for the shift operation of each forkshaft 11, 12 equipped with the forklift shaft 11, 12, thereby preventing any hindrance to proper shift operation.

In the embodiment shown in FIG. 6, instead of the elastic body 28 using a part of the retainer 21, the transmission case 1
Rod 3 installed so that it can slide against the inner wall of
0, elastic body 3 using a coil spring
8, and the flange-like end surface 3 of this rod 30.
The spring force of the elastic body 38 is applied to the back surface 26a of the reversing arm 26 through 0a.

In the embodiment shown in FIG. 7, an elastic body 38 having the same structure as the embodiment shown in FIG. 6 is provided in the portion 14b of the fifth shift fork 14 that the reversing arm 26 comes into contact with.

In each of the embodiments described above, the elastic body 28 or 38 is provided only in the path provided with the reversing arm 26 among the movement transmission paths of the braking force release mechanism 22. On the other hand, the embodiment shown in FIG.
An elastic body 48 is provided in the motion transmission path when the 2nd forkshaft 11 or the 3rd-4th forkshaft 12 is shifted to the right in FIG. That is, in the embodiment shown in FIG. 8, a cap 40 is slidably attached to the end of each fork shaft 11, 12 that comes into contact with the overhanging portion 23 of the 5th shift fork 14, and the inner surface of this cap 40 and each Folkshaft 1
An elastic body 48 made of a coil spring is incorporated between the end faces 1 and 12.

In this way, the elastic bodies 28, 3 of each configuration described above
As long as 8 and 48 are operation transmission paths of the braking force release mechanism 22, they can perform their functions even if they are provided between any of the members that make up the brake force release mechanism 22.

(Effect of the invention) As described above, the present invention has a part of the release action transmission path of the braking force release mechanism that is larger than the acting force of the SMEA spring acting on the shift fork of the synchromesh device. By incorporating an elastic body that exerts a reaction force, there is no problem with the function of the braking force release mechanism, and the excessive stroke of the braking force release operation due to variations in dimensional tolerances of the various components that make up the mechanism. can be absorbed by the spring force of the elastic body, and unnecessary loads can be avoided from being applied to the components of the braking force release mechanism due to the excessive stroke. Such situations can also be prevented. Moreover, the excessive stroke of the braking force release mechanism can be absorbed by setting the stroke of this mechanism slightly larger in consideration of variations in the dimensional tolerances of each component. This can also eliminate the fear that this may occur.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention; FIG. 1 is a sectional view showing a part of the inside of a gear transmission, FIG. 2 is a sectional view taken along the line - - in FIG. 1, and FIG.
4 and 5 are enlarged plan views showing different states of movement in the main part of FIG. 1, and FIGS. 6 and 7 are diagrams showing the second and third embodiments, respectively. A partially broken plan view corresponding to FIG. 4, and FIG. 8 shows the fourth embodiment as the third embodiment.
FIG. 3 is a cross-sectional view corresponding to a part of the figure. 1...Transmission case, 2...Countershaft, 6...Synchronized mesh device, 11, 12...
...Forkshaft, 14...Shift fork,
20... Shape memory alloy spring, 22... Braking force release mechanism, 26... Reversing arm, 28,3
8,48...Elastic body.

Claims (1)

[Scope of utility model registration request] When the oil temperature in the transmission case exceeds a certain value, a shape-memory alloy spring that deforms causes the shift fork of the synchro-mesh device to slide from its neutral position in the shift direction, causing the synchro-mesh device to rotate accordingly. The synchronous action applies braking force to the shaft that rotates in response to torque transmission from the engine in the neutral state of the transmission, and when the fork shaft for the shift fork, which is different from the shift fork described above, is shifted. By reversing the shift operation of the forkshaft through a reversing arm that rotates directly when the direction is opposite to the acting direction of the shape memory alloy spring, or in conjunction with this when the direction is the same,
In either case, an abnormal noise prevention device for a gear transmission is provided with a braking force release mechanism that pushes the shift fork of the synchronized mesh device back to a neutral position to release the braking force, wherein the braking force release mechanism An elastic body is incorporated in a part of the release action transmission path to exert a larger reaction force against the force of the shape memory alloy spring acting on the shift fork of the synchromesh device. Abnormal noise prevention device for gear transmissions.