JPH0218380Y2 - - Google Patents

Description

[Detailed explanation of the invention] (a) Technical field of the invention The present invention relates to an automatic transmission for a vehicle, etc., and more specifically, an automatic transmission equipped with an interlock mechanism operated by electrical operation or fluid pressure operation. Concerning improvement of the shift mechanism of the machine.

(b) Background of the technology In recent automatic transmissions for vehicles, the operability during gear shifting has improved due to the extensive introduction of electronics technology, but on the other hand, in the unlikely event that some part of the electrical system or fluid pressure system malfunctions. If this occurs, there is an increasing possibility that it will lead to an unexpected situation.

(c) Prior art and problems Regarding the shift mechanism in a conventional automatic transmission, for example, the structure shown in FIG.
(Refer to Publication No. 17094 and Japanese Unexamined Patent Publication No. 170955/1983)
There is something. In this case, a plurality of shift fork shafts b are provided for each shift fork a required for the number of gears, and a shift controller (not shown) electrically or pneumatically operates an actuator c that engages with the shift fork shaft b. Therefore, when changing gears, it is possible to automatically perform a shift operation according to the vehicle speed, etc.

However, in the conventional structure as described above, there is no means for preventing malfunction of the electrical system or pneumatic system for operating the actuator c, or between the actuator c and the shift fork. If some kind of trouble occurs in a part of the pneumatic system, this will cause actuator c to malfunction, and a shift fork other than shift fork a, which should have been set, may be set, resulting in unexpected damage or damage to the transmission. There was a possibility that a malfunction would occur.

In addition to the above, there is a technique disclosed in Japanese Utility Model Publication No. 15878/1983 as a transmission shift device equipped with a shift lock mechanism.

(iv) Purpose of the invention The present invention was made in view of the above-mentioned problems, and its purpose is to prevent errors in the shift mechanism caused by failures in the electrical system or fluid pressure system. It is an object of the present invention to provide a shift mechanism for an automatic transmission that can prevent operation and perform selection operations smoothly and reliably.

(E) Structure of the invention In order to achieve the above object, the shift mechanism of the automatic transmission according to the invention is installed in the casing of the transmission so as to be slidable in the axial direction in parallel with the main shaft, and is capable of adjusting the number of gears. One shift fork shaft is fitted with a plurality of shift forks according to the axial direction so as to be slidable in the axial direction and has a plurality of engagement grooves for locking plates on the outer circumferential surface, and the above-mentioned shift forks are sandwiched and attached to the casing. a plurality of locking plates having a pair of engagement claws that engage with each provided guide hole for the locking plate, and that are slidably movable on the outer circumferential surface of the shift fork and capable of engaging with the engagement groove for the locking plate; Then, the piston inserted into each of the locking plate guide holes urges the designated locking plate toward the shift side, and the engaging claw of the locking plate is engaged with the locking plate engaging groove. a lock actuator group that locks the shift fork to the shift fork shaft via a locking plate; The lock mechanism includes a group of engagers that are slidably inserted into each through hole extending in the radial direction of each piston, and a group of engagers that extend inside the casing and prevent each engagement from occurring. It is slidably inserted into a guide hole communicating with the through hole of the piston, and when one specified lock actuator is locked, an engager other than this lock actuator is caused to protrude into the guide hole. It has a lock member that prevents locking operation of an undesignated lock actuator.

(g) Example of the invention An example of the invention will be described below based on FIG. 1.

In the figure, a shift mechanism 1 of an automatic transmission includes a shift fork shaft 3 within a casing 2 of the transmission in parallel with a main shaft (not shown).

The shift fork shaft 3 includes a shift fork 4 for 5th-4th speed, and a shift fork 4 for 3rd-speed from the engine side.
A shift fork 5 for 2nd speed and a shift fork 5 for reverse-1st speed are respectively fitted and installed so as to be slidable in the axial direction.

Further, as shown in FIG. 2, a shift actuator (air cylinder) 6 is attached to one end of the shift fork shaft 3, and supplies air to either the air chamber 7 or the air chamber 8. ,
By sliding the piston 9 so as to release the other air, the shift fork shaft 3 is configured to be able to move in the axial direction (in the direction of arrow A in the figure).

Furthermore, a plurality of locking plate engagement grooves 40, 41, 4 are provided on the outer peripheral surface of the shift fork shaft 3.
2, 43, and locking plates 50, 52 having engaging pawls 44, 45, 46, 48 that can be respectively engaged with the locking plate engaging grooves 40-43 are inserted into the guide holes of the casing 2. 5
4.56 between the shift fork 4 and the locking plate 50 and the shift fork 5
Release springs 58 and 60 are installed between the locking plate 52 and the locking plate 52.

As shown in FIG. 4, the locking plates 50, 52 have a U-shaped cross section, and each of the engaging claws 44, 45, 46, 48 engages the outer peripheral surface of the shift forks 4, 5. and is slidably engaged with the guide holes 54 and 56 of the casing 2. Further, each locking plate 50, 52 is urged toward the air pistons 14, 15 by release springs 58, 60. When the locking plates 50, 52 are urged toward the shift fork shaft 3 by the operation of the air pistons 14, 15, the respective engaging claws 44-48 are engaged in the locking plate engaging grooves 40-43. configured to match. In order to perform this engagement more smoothly and reliably, in this embodiment, as shown in FIG. The plate engagement grooves 40 to 43 are formed in a tapered shape. Furthermore, locking plates 50, 52
The shoulders 50a, 50b, 52a, 52b are also formed in a tapered shape, and the locking plate engagement groove 5 of the casing 2 that engages with these shoulders
4 and 56 are also formed in a tapered shape. In this embodiment, when a select operation is commanded, for example, as shown in FIG. slides on the outer peripheral surface of the shift fork 5 and engages with the locking plate engagement grooves 42 and 43, so the locking plate 52 causes the shift fork 5 to
is locked to the shift fork shaft 3, allowing the selection operation to be performed smoothly and reliably. By moving the shift fork shaft 3, only the shift fork 5 is shifted, as shown in FIG.

At the upper end of the casing 2, lock actuators 10 and 11 for select locks are installed parallel to the shift fork shaft 3 and at positions corresponding to the respective shift forks 4 and 5.

The lock actuator 1 is disposed in the casing 2 parallel to the shift fork shaft 3.
Engaging elements 26, 2 that engage in through holes 22, 23 formed in air pistons 14, 15 in 0, 11
A select lock mechanism 31 comprising 7 is provided.

The select lock mechanism 31 includes an engager 26,
27 and rods 28 and 29 arranged between them
and a guide hole 30 that accommodates these. And this select lock mechanism 3
1, an actuator (not shown) that interlocks with the shift fork shaft actuator 6 is attached to one end of the rod 28, and the engager 2
6, 27 and rods 28, 29 in the axial direction, the engagers 26, 27 engage the pistons 14, 27.
15 through holes 22 and 23 or disengaged from each other.

Further, in this embodiment, when the air piston 15 is lowered, the rod 28 and the select lock ball 32 cause the engager 26 to move toward the air piston 14.
The air piston 14 protrudes from the through hole into the guide hole 30, and the downward movement of the air piston 14 is prevented. Therefore, even if some abnormality occurs in the electrical system, the air piston 14 can be prevented from moving downward along with the downward movement of the air piston 15, and in the unlikely event that some abnormality occurs in part of the electrical system or fluid pressure system. Even if this occurs, the other shift forks will not be shifted, so a failure at one location will not affect the shift forks.

When drilling the locking plate engagement groove in the shift fork shaft, an annular locking plate engagement groove 62 is bored as shown in FIG. 4
By forming semicircular cuts in the central portions of the locking plates 50, 52 and the shift fork shaft, the locking plates 50, 52 and the shift fork shaft can be more securely locked than in the previous embodiment.

Further, in this embodiment, since the sliding area between the locking plates 50, 52 and the casing 2 is large during shifting, the surface pressure is reduced, which is advantageous in terms of wear.

(G) Effect of the invention As explained above, according to the invention, a plurality of locking plate engagement grooves are bored on the outer peripheral surface of one shift fork shaft, and each locking plate engagement groove is A locking plate having a pair of engaging pawls that can be engaged with the shift fork is engaged with the casing so that each of the engaging pawls can slide around the outer peripheral surface of the shift fork, and the specified locking plate is shifted by operation of the actuator. The specified locking plate is biased toward the fork side to lock into the shift fork shaft, and it also prevents multiple locking plates from locking into the shift fork shaft at the same time, so electrical system and fluid pressure Even in the event that a failure occurs in the system, it is possible to prevent malfunction of the shift mechanism caused by the failure, and the excellent effects of being able to perform the selection operation smoothly and reliably can be obtained.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram in neutral state showing an embodiment of the present invention, Fig. 2 is a sectional view of essential parts of the shift mechanism,
FIG. 3 is a configuration diagram showing the state of the shift mechanism according to the present invention during shifting, FIG. 4 is an explanatory diagram of the configuration of the locking plate, and FIG. 5 is an enlarged configuration diagram of the main parts of the locking plate according to the present invention. FIG. 6 is a perspective view of a locking plate showing another embodiment of the present invention;
The figure is a perspective view showing a shift mechanism of a conventional automatic transmission. In the drawings, 1 is a shift mechanism, 2 is a casing, 3 is a shift fork shaft, 4, 5 are shift forks, 10, 11 are lock actuators, 31 is a lock mechanism, 40, 41, 42, 43
are locking plate engagement grooves, 44, 45, 4
6 and 48 are engaging claws, 50 and 52 are locking plates, and 58 and 60 are release springs.

Claims (1)

[Scope of utility model registration request] A plurality of locking plates are attached to the casing of the transmission so as to be slidable in the axial direction in parallel with the main shaft, and a plurality of shift forks corresponding to the number of gears are slidably fitted in the axial direction, and a plurality of locking plates are provided on the outer peripheral surface. One shift fork shaft having an engagement groove for the above-mentioned shift fork is held between the shift fork shaft and engages with each locking plate guide hole provided in the casing, and is slidably movable on the outer circumferential surface of the shift fork. A plurality of locking plates each having a pair of engagement claws that can be engaged with the locking plate engagement groove, and a piston inserted into each of the locking plate guide holes, move the designated locking plate to the shift side. a group of lock actuators that are energized to engage an engaging claw of the locking plate in the locking plate engagement groove to lock the shift fork to the shift fork shaft via the locking plate; a locking mechanism that prevents the actuator group from simultaneously locking the plurality of shift forks to the shift fork shaft by the plurality of locking plates;
The lock mechanism includes a group of engagers slidably inserted into each through hole extending in the radial direction of each piston, and a guide hole extending inside the casing and communicating with the through hole of each piston. When a specified lock actuator is slidably inserted and locks, an engager other than this lock actuator is projected into the guide hole to lock the lock actuator other than the specified lock actuator. 1. A shift mechanism for an automatic transmission, comprising a locking member for blocking the shifting.