JPH0210368Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention is a mechanism that applies braking force to a rotating shaft during idling, in order to prevent abnormal noises in a gear transmission for a vehicle. This invention relates to a device that sometimes releases the braking force.

Prior Art As this type of braking force generation mechanism and its release device, various configurations have already been proposed by the same applicant as the present application (for example, the Showa
(See 1958 Utility Model Registration Application No. 27479). To give an overview of the braking force generation mechanism of this earlier application, in a transmission equipped with a synchromesh device on the shaft of a shaft rotating in a neutral state, a shift fork that provides a shift force to the synchromesh device is connected to the fork shaft. A spring made of shape memory alloy (hereinafter abbreviated as "SMEA") that deforms when the oil temperature in the transmission exceeds a certain value is installed on the shaft of this forkshaft so that it can be slid relatively in the shift direction. are placed. As a result, when the oil temperature in the transmission case exceeds a certain value, the SMEA spring deforms to apply a shifting force to the synchronized mesh device, and the synchronized action of this applies braking force to the rotating shaft. It gives.

By the way, when the transmission is shifted, it is necessary to release the braking force on the shaft in order to avoid loss of torque and improve durability. For this reason, the fork shaft (5th-
Other forkshafts (1st-
2nd, 3rd-4th) is shifted,
This shift fork must be pushed back to the neutral position regardless of the function of the SMEA spring. In this case, for example, when the fork shaft for 1st-2nd is operated in the opposite direction to the sliding direction of the fork by the SMEA spring, that is, in the 2nd shift direction, the fork shaft can be easily neutralized using the movement of this fork shaft. Can be pushed back into position. However, for example, 1st−2nd
The fork shaft is in the same direction as the fork slide direction by the SMEA spring, that is, the 1st
When operated in the shift direction, the movement of the forkshaft must be reversed to act on the fork.

As a countermeasure for this, the earlier application mentioned above is
By using the cam surface formed on the outer periphery of each fork shaft for 3rd and 4th use, and the release ball that is built into the shift fork side and is always pressed against the outer periphery of the fork shaft with spring force, these The motion of the fork shaft is inverted and transmitted to the fork. In this case, the force that pushes the fork back to the neutral position against the force of the SMEA spring relies on the component of the spring force acting on the release ball, which makes it difficult to adjust this spring force, and There was a risk that the push-back operation would become uncertain.

Furthermore, since the release ball is always in pressure contact with each forkshaft with a spring force, there is a problem in that there is resistance to the shift operation of these forkshafts or the sliding movement of the fork by the above-mentioned SMEA spring.

Purpose of the invention The purpose of the invention is to prevent the shift fork from shifting when any other forkshaft other than the basic forkshaft is shifted in the same direction as the shift fork by the SMEA spring.
To provide a release device for a braking force generation mechanism that can reliably push back to a neutral position against the elasticity of an SMEA spring, and that can smoothly slide a shift fork and shift each fork shaft using an SMEA spring. It is to be.

Configuration of the Invention In order to achieve the above object, the release device of the braking force generation mechanism for preventing abnormal noise in the present invention is configured as follows.

That is, the synchromesh device is disposed on the shaft that rotates in response to torque transmission from the engine when the transmission is in a neutral state. A shift fork that applies a shifting force to the synchromesh device is supported on the axis of the basic fork shaft so as to be slidable along its axis. This shift fork is caused by the deformation of the shape memory alloy spring when the oil temperature in the transmission exceeds a certain value, and an acting force that causes the shift fork to slide within a predetermined range from the neutral position in the shift direction along the basic fork shaft. It is becoming more and more popular. By sliding the shift fork at this time, the synchromesh device performs a rotation synchronization action.

When the other fork shafts arranged parallel to the basic fork shaft are shifted in the direction opposite to the direction of the force acting on the shift fork due to the deformation of the shape memory alloy spring, It is arranged so as to come into contact with a part of the shift fork and push the shift fork back to the neutral position. Also, other forkshafts other than the basic forkshaft are provided with reversing arms. When the fork shaft is shifted in the same direction as the direction of the force acting on the shift fork due to the deformation of the shape memory alloy spring, this reversing arm comes into contact with a predetermined stationary part and receives rotational movement. , acts to push the shift fork back to the neutral position.

Embodiments Hereinafter, the configuration of the present invention will be explained using embodiments shown in the drawings.

In FIG. 1, which shows a cross section of a part of the inside of a gear transmission, and FIG. 2, which shows a cross section taken along the line - in FIG. 1, a transmission case (transaxle case) 1
A counter shaft 2 and an output shaft 3 are rotatably supported inside. 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. A large diameter gear 4 for the 5th gear rotatably supported on the axis of the countershaft 2 is connected to a small diameter gear 5 for the 5th gear supported on the axis of the output shaft 3 so as to rotate together with this shaft 3. They are always engaged. 5th
The synchronized mesh device (hereinafter referred to as "synchronized device") 6 is also connected to the countershaft 2.
The large-diameter gear 4 is arranged adjacent to the large-diameter gear 4 on the axis of the gear.

As is well known, this synchronizing device 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 as shown in FIG. 2 is engaged with a fork engaging groove 8a formed on the outer periphery of the hub sleeve 8. Assuming that a shift operation to 5th is now performed, the hub sleeve 8 of the synchronizer 6 is slid from the position shown in FIG. 1 toward the large diameter gear 4 through the shift fork 14. Accordingly, the inner tapered cone surface 10a of the synchronizer ring 10 is pressed against the outer tapered cone surface 4a of the large diameter gear 4 through the shifting key 9 that moves together with the hub sleeve 8. As a result, the synchronizer ring 10 rotates together with the clutch hub 7, hub sleeve 8, etc., and the large diameter gear 4 which is constantly engaged with the small diameter gear 5 (not rotating during idling) on the output shaft 3.
Frictional torque is generated between the mutually tapered cone surfaces 10a and 4a, and based on this, a rotational synchronization effect is achieved between the countershaft 2 and the large diameter gear 4 on the shaft. Therefore, when the engine is idling, a braking force is applied to the rotating countershaft 2 by the above-mentioned synchronous action.

After the above-mentioned synchronizing action, as the hub sleeve 8 is further slid, a final synchronizing action due to pressure contact between the channel of the internal spline teeth of the hub sleeve 8 and the channel of the synchronizer ring 10 is performed. The internal spline teeth of the hub sleeve 8 mesh with the spline teeth 4b formed integrally with the radial gear 4, completing the shift to 5th.

Now, as is clear from FIG. 2 and FIG. 3, which is a cross-sectional view taken along the line - in FIG.
Folkshaft 12 for 3rd-4th and 5th-
The fork shafts 13 for REV are parallel to each other,
Moreover, they are disposed so as to be slidable in the axial direction by a shift operation for each.

Here, forkshaft 13 for 5th-REV
is called the "basic forkshaft" to distinguish it from the other two forkshafts 11 and 12.As is clear from FIG. Boss portion 14a of the aforementioned shift fork 14 for 5th
are assembled so that they can slide relative to each other in the axial direction. Also, this flange button 1
A flanged sleeve 16 is assembled on the outer periphery of the fork shaft 5, and the bush 15 and the sleeve 16 are both axially positioned with respect to the basic fork shaft 13 by a clip 18, as shown in FIG. ing.

A normal coil spring 19 is interposed between the flange of the flanged bush 15 and the boss 14a of the shift fork 14. In addition, the flange portion of the flanged sleeve 16 and the boss portion 14 of the shift fork 14
A spring 20 made by SMEA is interposed between the a and the a. This SMEA spring 20 is in its most contracted state 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 the set value, the SMEA spring 20 stretches, and the shift fork 14 overcomes the force of the normal coil spring 19.
It will slide in the shift direction.

In addition, the shift fork 14 includes a 1st-2nd fork shaft 11 and a 3rd-4th fork shaft 12 other than the basic fork shaft 13.
An overhanging portion 23 that can come into contact with each end face of is integrally formed. That is, this projecting portion 23 is attached to a forkshaft 1 other than the basic forkshaft 13.
When 1 and 12 are shifted in the 2nd or 4th shift direction (rightward in Figure 3), which is opposite to the 5th shift direction, these forkshafts 1
1 and 12.

On the other hand, release heads 24 are fixed on the axes of the forkshafts 11 and 12 other than the basic forkshaft 13 by bolts 25, respectively, as is clear from FIG. As is clear from FIGS. 1 and 5, these release heads 24 have a reversing arm 2 formed in a curved shape.
6 are each rotatably attached to one end by a pin 27. The arcuate back surface 26a of each of these reversing arms 26 lightly contacts the bearing retainer 21, which is a stationary portion within the transmission case 1, as shown in FIG. This contact is not actively made when the forkshafts 11 and 12 are in the neutral position, but if the reversing arm 26 freely rotates in this state, problems such as the reversing arm 26 may occur. The reversing arm 2 is
It is also possible to make the back surface 26a of 6 actively abut against the bearing retainer 21.

In FIG. 3, reference numeral 17 indicates an interlock mechanism, and as is well known, when any one of the aforementioned forkshafts 11, 12, 13 is shifted, the remaining two fork shafts are shifted. It functions to lock the forkshaft in a neutral position.

In the above configuration, if the oil temperature in the transmission case 1 rises above a certain value while the engine is currently idling, the spring 20 manufactured by SMEA will expand, thereby causing the shift fork to shift as described above. 14 is pushed in the direction of shift to 5th with a constant stroke. As a result, the synchronizer 6 shown in FIG. 1 performs a rotation synchronizing action, and a braking force is applied to two rotations of the countershaft. As a result, fluctuations in engine rotation during idling are absorbed, and due to the backlash of each gear located on the axis of countershaft 2 and the gears (including gears 4 and 5 for 5th gear) that are constantly meshed with these gears. Abnormal noise can be suppressed.

When the oil temperature in the transmission case 1 decreases to below a predetermined value, the SMEA spring 20 contracts to its original state, or if the spring 20 has one-way characteristics, the pressing load on the shift fork 14 decreases. For this reason, shift fork 1
4 is pushed back to the illustrated neutral position by a normal coil spring 19, the synchronizer 6 also becomes neutral, and the braking force on the countershaft 2 is released. In this way, transmission case 1
When the viscous resistance of the lubricating oil is high (the oil temperature is below a certain value) and there is no risk of abnormal noise, the braking action on the countershaft 2 is released to improve the torque transmission efficiency of the transmission, the shift feeling, and the synchronizer 6. Care has been taken to ensure that the durability of the product is not adversely affected.

Now, the case where each shift operation is performed in a state where the oil temperature in the transmission case 1 is above a certain value and the braking force is applied to the countershaft 2 as described above will be described. First, it is assumed that either the 1st-2nd forkshaft 11 or the 3rd-4th forkshaft 12 is shifted to the left in FIG. 3 (shifting direction to 1st or 3rd). As a result, the release head 24 moves together with the forkshaft 11 or 12, and as a result, the pin 27, which is the rotational fulcrum of the reversing arm 26, moves in the same direction. At this time, since the back surface 26a of the reversing arm 26 is in contact with the bearing retainer 21 as described above, the reversing arm 26 rotates from the state shown by the solid line in FIG. 1 to the state shown by the imaginary line as the pin 27 moves. . That is, the tip of the reversing arm 26 moves in a direction opposite to the direction in which the pin 27 moves, and the tip of the reversing arm 26 moves toward the shift fork 14.
This fork 14 is brought into contact with a part 14b of the
Push it back from the shift position (the position that applies braking force to the countershaft 2) to the neutral position shown in the figure against the elasticity of the SMEA spring 20. As a result,
The braking force on the countershaft 2 is reliably released by utilizing the rotation of the reversing arm 26 as the forkshaft 11 or 12 shifts.

In addition, since the reversing arm 26 does not interfere with the shift fork 14 side at all when the fork shafts 11 and 12 are in the neutral position, it is not possible to apply braking force to the countershaft 2 by, for example, the spring 20 made by SMEA, or the like. Releasing is performed properly without receiving any unnecessary operating resistance. Furthermore, the shift operation of the forkshaft 11 or 12 can be performed smoothly without impairing the operation feeling.

In addition, either forkshaft 11 for 1st-2nd or forkshaft 11 for 3rd-4th is to the right in Fig. 3 (shift direction to 2nd or 4th).
When the shift operation is performed, the overhanging portion 23 of the shift fork 14 is pushed by the end face of the fork shaft 11 or 12. As a result, the shift fork 14 is pushed back from the shift position to the neutral position against the elastic force of the SMEA spring 20, as in the case described above. Therefore, the braking force on the countershaft 2 is also released when shifting to 2ud or 4th.

When operating the 5th or reverse (REV) shift, the basic fork shaft 1 equipped with the shift fork 14 and the SMEA spring 20 is used.
3 itself moves to the left or right in FIG. Therefore, the influence of the SMEA spring 20 on the shift fork 14 is eliminated, and the braking force on the countershaft 2 is also naturally released.

Effects of the invention This invention uses the deformation of the shape memory alloy spring when the oil temperature in the transmission exceeds a certain value to slide the shift fork on the shaft of the basic forkshaft within a predetermined range, thereby reducing idling. In a braking force generation mechanism configured to apply a braking force to a rotating shaft by the rotational synchronization action of a synchromesh device provided on the shaft, when the transmission is shifted, In particular, when a forkshaft other than the basic forkshaft is shifted in the same direction as the direction of the force acting on the shift fork due to the deformation of the shape memory alloy spring, the reversing arm provided on this forkshaft By the rotation of the shift fork, the shift fork can be reliably pushed back to the neutral position, thereby accurately releasing the braking force on the shaft.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a plan cross-sectional view showing a part of a gear transmission, FIG. 2 is a cross-sectional view taken along the - line in FIG. 1, and FIG. 4 is a sectional view taken along the line -- in FIG. 3, and FIG. 5 is an external perspective view showing the main part of FIG. 2. 2...Countershaft, 6...Synchronizer, 11, 12, 13...Forkshaft, 1
4...Shift fork, 20...SMEA spring, 21...Stationary member (bearing retainer), 23...Protruding portion of fork, 24...Release head, 26...Reversing arm.

Claims (1)

[Scope of Claim for Utility Model Registration] A synchronizer that applies braking force to the rotation of the shaft by synchronizing the rotation during shift operation, on the shaft of the shaft that rotates in response to torque transmission from the engine when the transmission is in neutral. A mesh device is provided, and a shift fork that applies a shifting force to the synchronized mesh device is supported so as to be slidable along the axis of the basic fork shaft, and this shift fork maintains a constant oil temperature in the transmission. Due to the deformation of the shape memory alloy spring when the value exceeds the value, the synchromesh device receives a force that causes it to slide within a predetermined range from the neutral position in the shift direction along the basic forkshaft. In a braking force generation mechanism for preventing abnormal noise in a gear transmission configured to achieve a rotational synchronization effect, other forkshafts arranged parallel to the basic forkshaft are connected to the shape memory alloy spring. is arranged so as to abut a part of the shift fork and push the shift fork back to the neutral position when the shift operation is performed in the direction opposite to the direction of the force acting on the shift fork due to the deformation of the shift fork; Other forkshafts other than the forkshaft have a structure in which the forkshaft comes into contact with a predetermined stationary part when the forkshaft is shifted in the same direction as the direction of the force acting on the shift fork due to the deformation of the shape memory alloy spring. A release device for a braking force generation mechanism for preventing abnormal noise in a gear transmission, which is provided with a reversing arm that receives rotational movement and acts to push the shift fork back to a neutral position.