JPS5822648B2 - Inertia lock type synchromesh transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inertia-lock synchromesh transmission.

Inertial lock type synchromesh transmissions, such as the Borgwana complete synchromesh transmission, are widely used as transmissions for passenger cars in Japan, but recently this type of transmission has developed a so-called "two-stage" phenomenon. The problem is that it occurs.

The phenomenon called ``two-gear shift'' occurs when you perform a gear shift operation in this type of transmission, where you first feel some resistance on the shift lever, then the resistance disappears, and then strong resistance is felt on the shift lever again. It is a phenomenon that makes you feel powerful.

Although this phenomenon is not caused by a defect in the power transmission mechanism of this type of transmission, it is a problem with automobile products in that it causes the driver to make a shift error and reduces the shift feeling when shifting. It becomes a factor that reduces the value.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an inertia-tack type synchromesh transmission that reduces the occurrence of the above-mentioned "double-stage" phenomenon.

Embodiments of the present invention will be described below with reference to the attached drawings, but prior to this, the mechanism of the occurrence of the "two-step entry" phenomenon will be explained with reference to FIGS. 1 to 9 of the attached drawings. put.

FIG. 1 is a longitudinal sectional view of a main part of a known inertia lock type synchromesh transmission 1 to which the present invention is applied.

In FIG. 1, reference numeral 6 denotes an output shaft, and a high-speed gear 4 is loosely fitted onto the output shaft 6 and meshes with a gear 3 on a subshaft 2 which is constantly rotated.

Another gear 5 on the subshaft 2 meshes with a low speed gear 7 loosely fitted on the output shaft 6 via a pairing 8.

A spline 6a is formed on the outer peripheral surface of the output shaft 6 at an intermediate position between the two front gears 4 and 7.

A clutch hub 9 that engages with the spline is fitted onto the spline 6a, and the clutch hub 9 is prevented from moving in the axial direction between the two gears 4 and 7.

The crack hub 9 has a large number of spline teeth over its entire outer circumferential surface, and has key grooves for accommodating the shifting keys 10 at three locations on the outer circumferential surface.

The shifting key 10 can slide in the key groove parallel to the axis of the clutch hub 9, and is constantly pressed against the inner peripheral surface of the sleeve 12 by a ring-shaped key spring 11.

The sleeve 12 has splines formed on its inner peripheral surface and is mounted on the clutch hub 9 via the shifting key 10.

The low-speed gear 7 and the high-speed gear 4 each have spline pieces 7A, 4A having conical cone portions fixed to opposing end faces, and these spline pieces 7A, 4A
Gear spline 7a adjacent to the maximum outer diameter end of the cone portion of
, 4a are formed.

A synchronizer ring 13.14 having outer peripheral spline teeth 13a14a is loosely fitted on the outer peripheral surface of the cone portion, and a shifting key 1 is fitted in grooves 13b14b formed at three locations on the outer peripheral surface of the synchronizer ring 13.14.
0 end is inserted loosely.

A circumferential groove 12a extending in the circumferential direction is formed on the outer peripheral surface of the sleeve 12, and a shift fork 15 that can move relative to the sleeve 12 only in the circumferential direction is fitted into the groove 12a. ing.

The shift fork 15 is fixed to a shift fork shaft 16 that is driven in the axial direction.

Next, the mechanism by which the ``two-stage'' phenomenon occurs in a known inertia lock type synchromesh transmission having the above-mentioned structure will be explained with reference to FIGS. 2 to 7.

The diagrams shown at the top in FIGS. 2 to 6 are schematic diagrams showing the engagement relationship between the outer circumferential spline of the synchronizer ring, the inner circumferential spline of the sleeve, and the gear spline of the gear. The figures shown below are longitudinal sections showing the respective axial positions.

In addition, in Figures 8 and 9, the vertical axis represents the change in the force applied to the shift lever and the change in the rotational speed of the synchronized side during these gearshift operations, and the horizontal axis represents the elapsed time, that is, the gear shift operation process. This is the graph shown.

FIG. 2 shows a state in which the speed change lever is in the neutral position, that is, a state in which power is not transmitted to the output shaft 6. In this state, the high speed gear 4 and the low speed gear 7 are connected to the output shaft 6. It's idling above.

Further, the clutch hub 9 and sleeve 12 are stationary or rotating together with the output shaft 6, and the shifting key 1
0 is the groove 13b of the synchronizer ring 13°14, 1
4b, without contacting the walls of the grooves 13b, 14b, and the synchronizer ring 13.14 is stationary or rotating relative to the spline pieces 4A, 7A of the gears 4, 7, respectively.

Now, suppose that the sleeve 12 is moved to the left in FIG. 1 via the shift fork 15 from the neutral state shown in FIG. 2 to perform an upshift operation to a high speed gear.
2, the shifting key 10 is also moved to the left in FIG. 2, and as a result, the tip of the shifting key 10 touches the synchronizer ring 1 as shown in FIG.
The synchronizer ring 13 is pressed against the end face of the groove 13b of No. 3, and is pushed by the shifting key 10 over the spline piece 4A of the high speed gear 4 to the left in FIG.

Therefore, friction occurs between the cone of the spline piece 4A of the high-speed gear 4 and the synchronizer ring 13,
At the same time as the synchronizer ring 13 starts rotating in the direction shown by the arrow f in FIG. Accordingly, a reaction force in the opposite direction to the direction in which the sleeve 12 is driven is applied to the shifting key 10 from the nizer ring 13.

Therefore, this reaction force is transmitted through the sleeve 12 to the shift lever.
(not shown) produces a resistive force labeled III in FIG.

In this case, the rotational speed of the sleeve 12, which was driven by the low-speed gear 7 before the shift operation, is lower than the rotational speed of the synchronizer ring 13, so the shifting key 10 is operated as a synchronizer as shown in FIG. −
It will be inserted into the groove 13b of the ring 13 in a biased state.

In the state in which the shifting key 10 and the synchronizer ring 13 are engaged as shown in FIG. 3, a force is further applied to the sleeve 12 via the shift lever to move it to the left in FIG. Continuing, the recess 12c on the inner peripheral surface of the sleeve and the protrusion 10 on the center of the upper surface of the shifting key 10
a is disengaged, the sleeve 12 pushes the shifting key 10 downward against the elastic force of the key spring 11, and as a result, the sleeve 12 climbs over the protrusion 10a of the shifting key 10 and moves to the high speed stage. Move toward gear 4.

Then, when the chamfered surface at the tip of the spline tooth 12b of the sleeve 12 comes into contact with the chamfered surface of the spline tooth 13a of the synchronizer ring 13, the movement of the sleeve 12 is temporarily stopped for a moment, and the synchronizer ring 1
3 is directly subjected to a force directed to the left in FIG. 4 from the sleeve 12.

Outer peripheral spline teeth 13a of synchronizer ring 13
If the tip of the synchronizer ring 13 and the tip of the spline tooth 12b on the inner circumference of the sleeve continue to be engaged as shown in FIG. bigger, synchronizer
The ring 13 has a torque of 1~T in the opposite direction to its rotational direction f.
acts, and as a result, the spline teeth 13a of the synchronizer ring 13 are connected to the spline teeth 12b of the sleeve 12.
It gradually moves in the direction shown by arrow T in FIG.

Finally, when the synchronizer ring 13 and the sleeve 12 reach the same speed, the spline tooth 12b of the sleeve 12 is connected to the spline tooth 1 of the synchronizer ring 13.
3a (see Fig. 5), and further collides with the tip chamfer surface of the spline tooth 4a of the high-speed gear 4 (see Fig. 5).
(see figure).

As described above, when the spline teeth 12b of the sleeve 12 enter between the spline teeth 13a of the synchronizer ring 13, the sleeve 12 has a cone portion of the spline piece 4A of the high speed gear 4 and the synchronizer ring 1.
Since the axial reaction force (the force that tries to push the sleeve 12 back to the right in Fig. 5) due to the friction with the shift lever does not work, the resistance force acting on the shift lever at this time is as shown in Fig. 8. It decreases greatly as shown at point V.

In this case, the sleeve 12 rests on the shifting key 10 as shown in FIG. The force trying to press the spline piece 4A against the cone portion becomes close to zero.

Spline teeth 1 of sleeve 12 as shown in FIG.
2b is the spline tooth 13 of the synchronizer ring 13
When the sleeve 12 passes through the gap between the two and engages with the chamfered end surface of the spline tooth 4a of the high-speed gear 4, the sleeve 12 is again subjected to a force in the opposite direction to the direction of movement, and this force is applied to the shift lever.
This appears as a resistance force indicated by the symbol ■ in Fig. 8.

This resistance force is applied to the spline teeth 12 of the sleeve 12.
b disappears when it enters between the spline teeth 4a of the high speed gear 4 as shown in FIG. 7 (see the position indicated by the symbol ■ in the graph of FIG. is completed.

In the above shift operation, the phenomenon in which the resistance force applied to the shift lever shows two maximum values as shown in the graph of FIG. 8 is called "two-stage shift".

This "two-stage entry" phenomenon does not only occur during upshift operations, but also appears during downshift operations (
(See FIG. 9) However, what worsens the shift operation feeling, that is, the shift feeling, is mainly the "two-gear shift" that occurs during the upshift operation.

The reason for this is that during an upshift operation, the synchronous direction of the synchronized side and the direction of the drag torque are the same, so the rotational speed of the synchronous wave synchronized side drops as shown by the broken line in Figure 8, and the synchronization occurs. This results in relative rotation between the sleeve and the spline teeth on the synchronized side, which must be constantly recovered by engagement between the sleeve and the spline teeth on the synchronized side.

This is also because the resistance force generated on the shift lever at the second time is larger than the resistance force generated on the shift lever at the first time (during synchronization).

In this respect, in a downshift operation, there is almost no relative rotation between the synchronized side and the synchronized side after synchronization, and the force required for synchronization, that is, the resistance force generated on the shift lever for the first time, is lower than that during an upshift operation. Because it is thick, the resistance force generated on the shift lever the second time is felt to be relatively small.

Also, in terms of frequency of use, upshift operations are far more common than downshift operations.

Therefore, while the "two gear shift" that occurs during a downshift operation is not given much importance, it is easily understood that "two gear shift" occurs due to almost the same reason during a downshift operation.

The graph in Fig. 9 is for explaining the "two-stage entry" phenomenon in downshift operation, and the symbol shown in the figure is
-■ indicate the magnitude of the shift lever resistance force corresponding to the states shown in FIGS. 2 to 7 during a downshift operation.

Further, the broken line indicates a change in the rotational speed of the synchronized side during the gear shift operation process.

The present invention provides an effective device for reducing the occurrence of the above-mentioned "double entry" phenomenon.

Next, with reference to FIGS. 10 to 13 of the attached drawings, an embodiment for reducing the occurrence of "two-stage entry" in an inertia lock synchromesh transmission, particularly a Borgwarna complete synchromesh transmission, will be described. .

Simply put, the principle of the present invention is that during the period from when the spline tip of the sleeve disengages from the spline tip of the synchronizer ring until it engages with the gear spline tip, the synchronizer ring is connected to the gear. It is characterized in that the rotational speed of the gear is suppressed from decreasing by pressing it against the gear.

In order to achieve this, in the method of the present invention, during the above period, the lower end of the shifting key is engaged with the end surface of the groove of one synchronizer ring, and at the same time the lower rear end of the shifting key is engaged with the end surface of the groove of one synchronizer ring. Other synchronizer - IJ
By engaging the bottom surface of the song groove, the synchronizer ring is pressed against the gear by the shifting key when the sleeve moves.

10 and 11 are diagrams showing the embodiment of the present invention as described above, when the tip of the spline of the sleeve 12 is released from the tip of the spline 13a of the synchronizer ring 13 (the 10th During the period from when the shifting key 10 is engaged with the distal end surface of the gear spline 4a (see FIG. 11), the synchronizer key 10 faces
The ring 13, 14 is shown engaged and oblique to the sleeve axis.

According to the method of the present invention, during the above period, especially the first
As shown in FIG. 0, at the moment when the spline tip of the sleeve 12 is released from the tip of the spline 13a of the synchronizer ring 13, the upper tip of the shifting key 10 touches four parts of the inner peripheral surface of the sleeve 12. The rear end of the key spring 11 is pressed down against the elastic force of the key spring 11, and its lower part engages with the bottom surface of the groove of the other synchronizer ring 14, and the lower end of the key spring 11 engages with the bottom surface of the groove of the synchronizer ring 13. engage.

As a result, the shifting key 10 is in an inclined state with respect to the sleeve axis.

As the sleeve 12 moves, the protrusion at the center of the upper surface of the shifting key 10 is used as an inclined surface against the sleeve 12, and as a result, the synchronizer ring 13
is pressed against the cone portion of the spline piece 4A of the high speed gear 4.

The pressing action of this synchronizer ring 13 is the first
The spline teeth of the sleeve 12 shown in FIG.
This continues until it engages with the spline teeth 4a of .

Therefore, due to the frictional force between the cone portion of the spline piece 4A of the high-speed gear 4 and the synchronizer ring 13, the rotational speed of the high-speed gear 4 on the synchronized side does not drop after synchronization.

In addition, since the lower rear end of the shifting key 10 is actively engaged with the bottom surface of the groove of the other synchronizer ring 14, the resistance force when the shifting key 10 is pushed down is used as a reaction force to apply the force to the synchronizer ring 13. can be given.

However, in the present invention, the shifting key is maintained in an inclined state during the above period so that the synchronizer ring continues to be pressed against the cone portion of the gear to be synchronized.
After synchronization, it is possible to prevent a decrease in the rotational speed of the gear on the synchronized side, and it is possible to reduce the remarkable two-step phenomenon caused by the presence of a large relative rotation between the synchronized side and the synchronized side.

During the above period, the shifting key 10 is maintained in a posture oblique to the moving direction of the sleeve 12, and the lower rear end of the shifting key 10 is pressed against the synchronizer ring 14 on the low speed gear side. As specific means for this, various methods may be considered as described below.

In other words, during the period from the moment when the tip of the spline tooth on the sleeve disengages from the tip of the spline tooth on the synchronizer ring until the tip of the spline tooth on the sleeve engages with the tip of the gear spline, the shifting key is The first condition is effective for maintaining the above posture.
As shown in Figure 2, (1) The rlja of the recess on the inner peripheral surface of the sleeve 12 and the length b of the protrusion of the shifting key 10 are as large as possible compared to the overall length.

(2) Spline teeth 13 of synchronizer ring 13
The distance from the tip of a to the tip of the gear spline 4a is greater than the distance l from the tip of the shifting key 10 to the starting point of the recess of the sleeve 12.

etc. may be mentioned as the main ones.

However, the present invention can be implemented using various design conditions other than those described above, and these design conditions are merely one example of the method of the present invention.

Fig. 13 compares the change in the synchronizer ring pressing force of the transmission improved by the present invention (solid line) with the change in the synchronizer ring pressing force of the conventional transmission (dashed line). The synchronizer ring pressing force is plotted on the horizontal axis, and the gear shift operation process is plotted on the horizontal axis.

In the figure, n, [111V...VU represent the synchronizer ring pressing force in the states shown in Figures 2, 3, 4, 7, respectively. ,especially,
X and XI represent the synchronizer ring pressing force in the states shown in FIGS. 10 and 11.

Referring to FIG. 13, it is clear that the present invention reduces the occurrence of "double entry".

As described above, according to the present invention, it is possible to reduce the occurrence of the ``two-stage shift'' phenomenon that has been a problem in the past, and it is possible to obtain an improved transmission that provides a good shift feel.

[Brief explanation of drawings]

Fig. 1 is a vertical sectional view of the main parts of a Borgwarna complete synchromesh transmission to which the present invention is applied;
Figures 7 to 7 are diagrams for explaining the "two-stage engagement" phenomenon that occurred in the 1-heran transmission shown in Figure 1, and are the operating states of the synchronization mechanism of the transmission shown in Figure 1. Figure 8 shows the resistance force applied to the shift lever and the rotational speed of the synchronized side on the vertical axis, and the gear shift operation process on the horizontal axis, and shows the resistance force applied to the shift lever during upshift operation. Figure 9 is a graph similar to Figure 8 that shows changes in the resistance force applied to the shift lever during downshift operation and the rotational speed of the synchronized side. FIG. 10 and FIG. 11 are diagrams for explaining the scales that can reduce the "double entry" phenomenon according to the present invention.
The figure corresponds to the state shown in FIG. 5, and FIG. 11 corresponds to the state shown in FIG. 6, respectively. Fig. 12 is a diagram for explaining two or three main conditions for embodying the present invention, and Fig. 13 is a diagram showing the synchronizer ring pressing force on the vertical axis and the gear shift operation process on the horizontal axis. 2 is a graph comparing and displaying changes in the synchronizer ring pressing force of the transmission improved by the invention and changes in the synchronizer ring pressing force of the conventional transmission. 4...High speed gear, 7...Low speed gear, 10...Shifting key, 12...
・Sleeve, 13゜14... Synchronizer
ring.

Claims (1)

[Claims] 1 A pair of gears that are spaced apart on the same axis and have conical cone portions protruding from mutually opposing end surfaces, and external spline teeth are formed on a part of the outer circumferential surface; a synchronizer ring having spline teeth; a sleeve disposed between the pair of synchronizer rings and having spline teeth formed on its inner peripheral surface;
In an inertia lock type synchromesh transmission comprising a shifting key that is driven in the axial direction by the sleeve to push the synchronizer ring when the sleeve moves in the axial direction, the spline teeth of the sleeve are During the period from the state in which the tip disengages from the tip of the spline tooth of the one synchronizer ring until it engages with the tip of the spline tooth of the adjacent gear, the lower tip of the shifting key engages with the tip of the spline tooth of the one synchronizer ring. - the lower rear end of the shifting key engages with the groove end surface of the ring, and the lower rear end of the shifting key engages with the bottom surface of the groove of the other synchronizer ring, and the shifting key pushes the synchronizer ring against the adjacent gear; An inertia lock type synchronized mesh transmission characterized by being configured to be attached.