JPH0225965Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Technical field of the invention The 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. This invention relates to improvements in the shift mechanism of.

(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 like that. 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 malfunctions between the electrical system or pneumatic system for operating actuator c, or between actuator c and shift fork a, so the electrical system Or, if some kind of trouble occurs in a part of the pneumatic system, this may cause actuator c to malfunction, causing a shift fork other than the shift fork a that should have been set to be set, resulting in unexpected damage to the transmission. There was a possibility that this could cause a malfunction or a malfunction.

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.

Therefore, the applicant has developed a shift mechanism for an automatic transmission that can prevent malfunctions of the shift mechanism even in the unlikely event that a failure occurs in the electrical system or fluid pressure system. has been proposed, and its configuration is shown in FIG.

In FIG. 6, shift mechanism 1 of an automatic transmission
A shift fork shaft 3 is provided in 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.

Furthermore, as shown in FIG. 7, 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 air from the other side, the shift fork shaft 3
is configured to be movable in the axial direction (direction of arrow A in the figure).

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.

Air pistons 14 and 15 are installed inside the lock actuators 10 and 11 and are urged downward by springs 12 and 13, and air pistons 14 and 15 are provided inside the lock actuators 10 and 11, and air pistons 14 and 15 are inserted through the shift fork shaft 3 from the lock actuators 10 and 11. Guide holes 18 and 19 into which lock pins 16 and 17 are movably inserted are formed between the shift forks 4 and 5.

The lock pins 16 and 17 are connected to springs 20 and 21 and shift lock balls 2 which are housed in guide holes 18 and 19 on the shift fork 4 and 5 sides.
4, 25 and the lock actuator 10, 11
Two air pistons are inserted between the inner air pistons 14 and 15. And this lock pin 16, 17
The shift forks 4, 5 and the shift fork shaft 3 can be engaged or disengaged when the air pistons 14, 15 are moved up and down by air pressure supplied to the lock actuators 10, 11. ing.

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.

In the figure, 32 and 33 are select lock balls, 34 and 35 are shift lock ball holes,
When shifting one shift fork 5, another shift fork 4 can slide on the shift fork shaft 3 and be fixed in a predetermined position.

With this configuration, once one shift fork 5 is selected for shift, the lock pin 17 is attached to the shift fork shaft 3.
If an abnormality occurs in the electrical system that controls the operation signal for supplying air to the lock actuators 10 and 11, the lock actuator 11 side will be locked. Since the piston 15 is inserted between the rods 28 and 29 of the select lock mechanism 31,
As a result, even if a malfunction instruction signal is transmitted to the lock actuator 10 side, the engager 26 engages between the through hole 22 and the guide hole 30, and the piston 14 is mechanically stopped. , it will not go down. Therefore, this lock pin 1
Since the shift fork 6 does not move, everything other than the shift fork 5 does not operate, and it is possible to prevent a failure of the electrical system from having an adverse effect on others.

However, in the above-mentioned shift mechanism, there is a risk that the shift fork 4 or shift fork 5 and the shift fork shaft 3 may be misaligned in the neutral state, and there is a risk that the selection operation cannot be performed smoothly and reliably.

(d) Purpose of the invention The present invention was made in view of the above-mentioned problems, and its purpose is to eliminate the positional deviation between the shift fork and the shift fork shaft when in neutral, and to perform the selection operation smoothly and reliably. An object of the present invention is to provide a shift mechanism for an automatic transmission that can perform automatic transmission.

(e) Structure of the invention In order to achieve the above object, the invention includes a plurality of shift forks that are slidably mounted in the axial direction in parallel with the main shaft within the casing of the transmission, and that correspond to the number of gears. A shift fork shaft that is slidably fitted in the axial direction, a lock actuator group that selects a specific shift fork and locks the shift fork to the shift fork shaft, and a lock actuator group that selects a specific shift fork and locks the shift fork to the shift fork shaft. In the shift mechanism of an automatic transmission, the shift fork shaft is provided with a lock mechanism that prevents a plurality of shift forks other than one shift fork from being simultaneously locked to the shift fork shaft. A plurality of engagement grooves are provided to regulate the position of the shift fork, and each shift fork is provided with a recess on the fitting surface with the shift fork shaft, and when in neutral, the shift fork protrudes from the recess and engages with the engagement groove. An engaging member is provided which is press-fitted into the recess by the bias of the shift fork shaft.

(F) Embodiment of the invention Hereinafter, a preferred embodiment of the invention will be described based on FIG.

In this embodiment, as shown in FIG. 1, engagement grooves 40 and 42 are bored on the outer circumferential surface of the shift fork shaft 3 to restrict the positions of the shift forks 4 and 5 in the neutral state. 4 and 5 are provided with recesses 44 and 46 on the fitting surfaces with the shift fork shaft 3, and in each recess 44 and 46, a groove protrudes from the recesses 44 and 46 and engages with the engagement grooves 40 and 42 when in neutral. During shifting, the recesses 44 and 46 are compressed by the bias of the shift fork shaft 3.
Locking balls 48, 50, which serve as engagement members that are press-fitted inside, are inserted via springs 52, 54, and other configurations are the same as those in FIG. Reference numerals are given and their explanations are omitted.

As described above, in this embodiment, the shift fork shaft 3 is provided with an engagement groove 4 that restricts the positional deviation between the shift fork shaft 3 and the shift forks 4 and 5 when in neutral.
0,42 and each shift fork 4,
5 are provided with locking balls 48, 50 that engage with the respective engagement grooves 40, 42, respectively, so that the shift fork shaft 3 and the shift fork 4, 5 can be reliably positioned in the neutral state, and the shift Even when one of the shift forks 4 and 5 is to be locked to the shift fork shaft 3, this selection operation can be performed smoothly and reliably.

FIG. 2 shows the structure of another embodiment of the present invention.

In this embodiment, the lock pin 16 shown in FIG.
17 etc. to lock the shift forks 4, 5, locking plates 60, 62
The shift fork 4, 5 is locked to the shift fork shaft 3 using the shift fork shaft 3, and the other configuration is the same as that in Fig. 1.
Identical parts are given the same reference numerals and their explanations will be omitted.

That is, engagement grooves 64 and 66 with which the tops of the locking plates 60 and 62 can engage are formed in the casing 2, and engagement claws 6 of the locking plates 60 and 62 are formed on the outer peripheral surface of the shift fork shaft 3.
an engagement groove 76 that can be engaged with 8, 70, 72, 74;
78, 80, 82 are drilled, and furthermore, recesses 84, 8 are formed at the tops of the shift forks 4, 5.
6 are bored, and springs 88, 90 are installed between the locking plates 60, 62 and the grooves 84, 86. Each locking plate 60, 62 has a spring 8
8 and 90 toward the air pistons 14 and 15, and can be lowered toward the shift fork shaft 3 along the outer peripheral surfaces of the shift forks 4 and 5 by the operation of the air pistons 14 and 15.

Therefore, in this embodiment, the positions of the shift fork shaft 3 and the shift forks 4, 5 when in neutral are regulated to predetermined positions by the engagement between the engagement grooves 40, 42 and the locking balls 48, 50. The shift fork shaft 3 and the shift forks 4 and 5 can be reliably positioned when in neutral. Furthermore, even when a specific shift fork, for example, shift fork 5, is selected and locked to the shift fork shaft 3 side, the locking plate 62 engages with the engagement grooves 80, 82 along the outer peripheral surface of the shift fork 5. ,
Select operations can be performed smoothly and reliably.

In each of the above embodiments, the locking ball 48,
As shown in FIG. 3, a leaf spring 92 is provided on the outer peripheral surface of each shift fork 4, 5 with a central portion protruding toward the shift fork shaft 3. The projections 94 of the leaf springs 92 are engaged with the engagement grooves 40 and 42, respectively, and are press-fitted into the recesses 51 during shifting by the biasing force of the shift fork shaft 3, or as shown in FIG. , the engagement member 96 having a semicircular tip end is slidably inserted into the recess 51 , the spring 100 is installed in the groove 98 of the engagement member 96 , and the tip end of the engagement member 96 is slidably inserted into the recess 51 . Even if the parts are engaged with the engagement grooves 40, 42, the shift fork shaft 3 and the shift fork 4, 5 can be reliably positioned in the neutral state.

Furthermore, in the embodiment shown in FIG. 1, an engagement element is disposed in the casing 2 to prevent the lock actuators 10 and 11 from locking a plurality of shift forks to the shift fork shaft 3 at the same time. However, even if the shift fork shaft 3 is equipped with a lock mechanism in which an engager is disposed to prevent the lock actuators 10 and 11 from locking a plurality of shift forks to the shift fork shaft 3 at the same time, Examples can be applied.

(g) Effects of the invention As explained above, according to the invention, a plurality of engagement grooves are bored in the shift fork shaft to restrict the positioning with each shift fork in the neutral position, and each shift fork has a neutral position. Since an engaging member that engages with the engaging groove is provided at the time, the shift fork shaft and each shift fork can be reliably positioned when in neutral, and the selection operation can be performed smoothly and reliably. This excellent effect can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing one embodiment of the present invention;
The figure is a sectional view showing another embodiment of the present invention, FIG. 3 is a sectional view of a main part showing another embodiment of the engaging member, and FIG. 4 is a sectional view showing still another embodiment of the engaging member. , FIG. 5 is a perspective view showing the shift mechanism of a conventional automatic transmission, FIG. 6 is a cross-sectional view of the shift mechanism that is the basis of the present invention, and FIG. 7 is a cross-section of the main part of the shift mechanism that is the basis of the present invention. It is a diagram. In the drawings, 1 is a shift mechanism, 2 is a casing, 3 is a shift fork shaft, 4 and 5 are shift forks, 10 and 11 are lock actuators, 16 and 17 are lock pins, 31 is a lock mechanism, and 40 and 42 are engagement units. Matching groove, 48, 50 are locking balls, 60, 62 are locking plates, 6
8, 70, 72, 74 are engaging claws, 92 is a leaf spring,
88, 90, and 98 are springs.

Claims (1)

[Scope of utility model registration request] A shift fork shaft is installed in the casing of a transmission so as to be slidable in the axial direction in parallel with the main shaft, and is formed by fitting a plurality of shift forks corresponding to the number of gears so as to be slidable in the axial direction. a lock actuator group that selects a shift fork and locks the shift fork to the shift fork shaft; and a lock actuator group that simultaneously locks a plurality of shift forks other than the identified shift fork to the shift fork shaft. In the shift mechanism for an automatic transmission, the shift fork shaft is provided with a plurality of engagement grooves for regulating the position of each shift fork shaft when in neutral, In addition to providing a recess on the fitting surface with the shift fork shaft,
A shift mechanism for an automatic transmission, characterized in that an engagement member is provided that protrudes from the recess and engages with the engagement groove when in neutral, and is press-fitted into the recess by the bias of a shift fork shaft during shift.