JPS62385B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transmission synchronizer, and more particularly to an improvement in a shifting key (synchronizer key) used in the synchronizer.

In the past, several synchronizing devices for automobile transmissions have been proposed, but the representative ones include a synchronizing hub fixed to the main shaft by spline fitting, and a synchronizing device fitted with splines around the outer circumference of the synchro hub. A coupling sleeve that slides in the axial direction by the shift fork, and a coupling sleeve that slides in the axial direction by the shift fork, and a coupling sleeve for transmission gears such as the first gear and the second gear A synchronizer ring that fits into a cone part and performs a clutch action by contacting the cone part, and a pair of synchronizer rings whose central part engages with a keyway formed in the synchronizer hub and whose end parts engage with notches of the synchronizer ring, respectively. A device is known that includes a rectangular parallelepiped-shaped shifting key (synchronizer key) that is constantly pressed against the inner surface of the coupling sleeve by an annular synchronizer spring.

However, such a synchronization device has the following drawbacks.

(i) Since a certain length is required for the shifting key, the synchro hub and synchro sleeve cannot be made very short, which imposes design constraints.

(ii) Since the shifting key is simply locked by pressing both ends of the shifting key with a pair of synchro springs,
The shifting key pops out from the synchro hub.

(iii) The synchronizer ring has notches (usually three) that are engaged with the ends of the shifting keys, so it is inferior in rigidity.

The present invention has been made in view of these points,
To provide a synchronizing device for a transmission which is compact, increases the rigidity of a synchronizer ring, and prevents the shifting key from popping out by configuring the shifting key with a cylindrical roller having a center hole. The main purpose is

DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below with reference to the drawings.

In FIGS. 1 to 4, 1 is a synchro hub whose boss portion 1a is inserted into the main shaft 2 and is spline-fitted, so that the synchro hub 1 and the main shaft 2 rotate integrally. It is composed of This synchro hub 1 is provided on its outer periphery with a spline 1b, a circumferential groove 1c, and a keyway 1d in which a shifting key 8, which will be described later, engages.

Reference numeral 3 designates an annular coupling sleeve, which has a spline 3a that engages with the spline 1b of the synchro hub 1 on its inner periphery, and a circumferential annular groove 3b that engages with the annular groove 3b on its outer periphery. The coupling sleeve 3 is configured to be able to slide on the synchro hub 1 in the axial direction of the main shaft 2 by the combined shift forks (not shown).

4 and 5 are synchronizer rings, each having a cone portion 4 formed corresponding to cone portions 6a and 7a of transmission gears 6 and 7 such as a first gear and a second gear.
a, 5a, splines 4b, 5b that fit with the spline 3a of the coupling sleeve 3, and a protrusion 4c that protrudes from the cone portions 4a, 5a so as to engage with the keyway 1d of the synchro hub 1. 5
and c.

A shifting key 8 is formed as a cylindrical roller having a center hole 8a, and is engaged with a key groove 1d of the synchro hub 1 so that its axis line coincides with the circumferential direction.

Reference numeral 9 denotes a spring made of a spring wire, which is inserted into the center hole 8a of the shifting key 8, and whose end portion 9a is bent to form a locking recess formed in the circumferential groove 1c of the synchro hub 1. 1e, thereby engaging and holding the shifting key 8 in the keyway 1d of the synchro hub 1.

Note that 3c is a circumferential recess formed in the inner periphery of the synchro hub 1, with which the shifting key 8 is removably engaged. 3d and 5d are chamfered portions of the spline 3a of the coupling sleeve 3 and the spline 5b of the synchronizer ring 5, respectively. 6b and 7b are splines of the transmission gears 6 and 7, respectively.

Next, the operation of the above device will be explained.

First, when the clutch is disengaged to change gears, the main shaft 2 is brought into a neutral state in which it is not connected to any of the transmission gears 6 and 7, as shown in FIG. Then, for example, main shaft 2
When connecting the gear 7 and one transmission gear 7, when the coupling sleeve 3 is pressed in the right direction R via a shift fork (not shown), the coupling sleeve 3 is engaged with the circumferential recess 3c of the coupling sleeve 3. The shifting key 8 also moves in the right direction R, and the outer peripheral surface of the shifting key 8 presses the protrusion 5c of the synchronizer ring 5.
The inner cone surface of the cone portion 5a of the synchronizer ring 5 is pressed against the surface of the cone portion 7a of the transmission gear 7.

In this manner, the synchronizer ring 5 becomes deviated by the gap between the keyway 1d and the protrusion 5c due to the frictional force with the cone portion 7a of the transmission gear 7, and starts synchronizing. Even if the coupling sleeve 3 attempts to further move in the right direction R, the shifting key 8 is prevented from advancing by the protrusion 5c of the synchronizer ring 5, so the shifting key 8 and the coupling sleeve 3 is disengaged from the circumferential recess 3c, and as a result, the chamfer 3d of the spline 3a of the coupling sleeve 3 and the chamfer 5d of the synchronizer ring 5 come into direct contact. In this state, as long as the rotation speeds between the coupling sleeve 3 and the transmission gear 7 are different, the coupling sleeve 3 is prevented from moving in the right direction R by the synchronizer ring 5, and the coupling sleeve 3 is prevented from moving in the right direction R. The pressing force is directly transmitted to the synchronizer ring 5.

In this state, the clutch action continues,
When the rotation speeds of the coupling sleeve 3 and the transmission gear 7 match and are synchronized, the splines 3a of the coupling sleeve 3 mesh with the splines 7b of the transmission gear 7 through the splines 5b of the synchronizer ring 5, as in the conventional case. , the connection between the main shaft 2 and the transmission gear 7 is completed (see FIG. 2).

Further, the main shaft 2 and the transmission gear 6 can be connected by pressing the coupling sleeve 3 to the left with a shift fork (not shown).

Since the present invention is configured as described above, it has the following various effects.

(i) Since the shifting key is constituted by a cylindrical roller, the length of the synchro hub in the axial direction can be shortened, and the synchro hub can therefore be made compact.

(ii) Since the shifting key has a center hole and a spring is inserted into the center hole and locked, there is no fear that the shifting key will pop out.
It doesn't have to be a book; just one is enough.

(iii) The synchronizer ring is provided with a protrusion that comes into contact with the shifting key, instead of having a notch that engages with the shifting key as in the past, increasing the rigidity and strength of the synchronizer ring. .

[Brief explanation of the drawing]

The drawings illustrate embodiments of the present invention, and FIG. 1 is a cross-sectional view of the essential parts of the transmission synchronizer in the neutral state, FIG. 2 is a cross-sectional view of the same essential parts in the shifted state, and FIG. FIG. 2 is a sectional view taken along the spline pitch circle of the synchro hub, and FIG. 4 is a sectional view taken along the - line in FIG. 1. 1... Synchro hub, 1d... Keyway, 2...
Main shaft, 3...Cut spring sleeve,
4, 5... Synchronizer ring, 4c, 5c...
...Protruding portion, 6, 7... Speed change gear, 8... Shifting key, 8a... Center hole, 9... Spring.

Claims (1)

[Claims] 1. A synchro hub that is spline-fitted to the main shaft and rotates integrally with the main shaft;
a synchro sleeve that meshes with the synchro hub;
The synchronizer ring has a cone portion corresponding to the cone portion of the transmission gear, and a shifting key that fits into a key groove provided in the synchronizer hub, and the shifting key has a cylindrical shape with a center hole. A spring inserted into a groove on the outer periphery of the synchro hub is inserted into the center hole of the shifting key, so that the shifting key is fitted and held in the key groove of the synchro hub, and is further inserted into the synchronizer ring. . A synchronizing device for a transmission, characterized in that a projection is provided that fits into the keyway.