JPH08200496A - Shift mechanism for transmission - Google Patents

Abstract

PURPOSE: To prevent a shift mechanism from being influenced by thermal expansion of a case without apprehension of increasing weight even when received in a cylindrical transmission case, in addition to the capability of lightening weight. CONSTITUTION: A shift fork 11, shift fork 12 and cylindrical parts 11a, 12a, 13a in an upper end of a shift fork 13 are slidably fitted respectively in an axial line direction to a shift rod 10. A cylindrical part 15a in an upper end of a shift fork 15 is movably fitted in an axial line direction to a shift rod 14 mounted in parallel to the shift rod 10. Further, a rotary sliding head 16 of selecting the shift forks 11, 12, 13 and 15 shifted is fixed to a central part in the axial line direction of the shift rod 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift mechanism of a transmission for the purpose of weight reduction, elimination of the number of parts, etc.

[0002]

2. Description of the Related Art In a conventional shift mechanism for a transmission having six forward gears and one reverse gear, a shift rod 5 is provided for each shift fork 50, 51, 52, 53 as shown in FIG.
4, 55, 56, 57 and shift heads 58, 59, 6
0,61 is required. Further, although not shown, a lock ball mechanism including a spring, a lock ball urged by the spring, and a groove with which the lock ball engages, which functions to receive the positioning and shift reaction force, is required. Further, in the 5th and 6th speed shift stages, the 5th and 6th speed shift head 61 is arranged on the shift rod 62 that is separately provided from the 5th and 6th speed shift rod 57. And the fifth and sixth speed shift rods 57
The shift rod 62 and the shift rod 62 are connected to each other by an inversion lever 63 that is swingably mounted on the equipment case so as to move in opposite directions.

[0003]

In the shift mechanism of the conventional transmission described above, when the shift mechanism is to be housed in the tubular transmission case, the shift rod must be extended or the like, which causes an increase in weight. There are problems that arise. That is, in the case of a tubular transmission case, depending on the casting method, the core may not be used, so a partition wall for supporting the shift rod cannot be provided at an intermediate position inside the case, The shift rod is supported at both ends in the axial direction of the case. Therefore, even if there is a shift rod which may be functionally short, the shift rod needs to be extended to be accommodated in the tubular transmission case.

If the entire transmission case is made of aluminum, the inversion lever 63 and the shift rods 57, 62, etc. supported by the case are caused by the difference in the coefficient of thermal expansion between the case and the iron-based parts inside the case. And the dimensional accuracy is impaired, which causes a problem that the operation feeling is adversely affected.

Therefore, according to the present invention, there is no fear that the weight will increase even if it is housed in a cylindrical transmission case, the weight can be reduced, and the shift of the transmission which is not affected by the thermal expansion of the case. The purpose is to provide a mechanism.

[0006]

In order to achieve the above object, according to a shift mechanism of a transmission of the present invention, a shift head portion is attached to a shift rod rotatably and axially movable in an equipment case. The shift forks of the respective shift speeds that are respectively provided are slidably mounted in the axial direction, and the shift rod has a shift operation projection that is disengageably engaged with a shift operation groove provided in the shift head portion. , Select the shift fork of each gear and shift,
It is characterized in that the sliding head is fixed, and a circumferential groove with which a lock ball biased by a spring provided on the equipment case is engaged is provided at a predetermined position in the axial direction of the shift rod.

[0007]

According to the present invention, first, the rotary fork / sliding head fixed to the shift rod is rotationally operated to position the shift operating projection in any one of the shift operating grooves to select the shift fork. Manipulate. Next, the rotary / sliding head is moved in the axial direction together with the shift rod in a state in which the shift operation projection is engaged with the shift operation groove, and the lock ball is engaged with the circumferential groove of the shift rod, thereby selecting. Shift the shift fork.

[0008]

Embodiments of the present invention will now be described in detail with reference to the drawings.

1 to 3 show an embodiment of the present invention. 1 is a plan view showing a shift mechanism of a transmission of the present invention with a part thereof omitted, FIG. 2 is an enlarged perspective view of a rotary / sliding head part, and FIG. 3 is a part of the shift mechanism of FIG. It is the expanded sectional view shown.

As shown in FIG. 1, this embodiment is applied to, for example, a shift mechanism of a transmission having six forward gears and one reverse gear, two shift rods, and a positioning mechanism (shift reaction force mechanism). By sharing it, the number of parts is reduced.

That is, a shift rod 10 is mounted in a device case of a transmission (not shown) so as to be rotatable and movable in the axial direction, and a retreat stage is provided at both ends of a central portion in the axial direction of the shift rod 10. Cylinders 11a, 12a, 13a at the upper ends of the shift fork 11, the first and second speed shift forks 12, and the third and fourth speed shift forks 13.
However, each is fitted so as to be slidable in the axial direction. Further, the tubular portion 15a at the upper end of the 5th and 6th speed shift fork 15 is fitted to the 5th and 6th speed shift rod 14 mounted parallel to the shift rod 10 in the equipment case so as to be movable in the axial direction. There is. Further, the shift fork 11 at the reverse stage and the first
A rotary / sliding head 16 is fixed to select and shift the second speed shift fork 12, the third and fourth speed shift forks 13 and the fifth and sixth speed shift forks 15.

The distal end of the arm member extending along the shift rod 10 from the cylindrical portions 11a, 12a, 13a,
Shift head portions 11b, 12b, 13b having shift operation grooves 11c, 12c, 13c are provided on the side surface portion facing the rotary / sliding head 16, respectively. Further, the shift operation groove 15c is formed at the tip of the arm member extending from the tubular portion 15a along the fifth and sixth speed shift rods 14.
Is provided with a shift head portion 15b.

A sleeve 17 is fitted and fixed to a central portion in the axial direction of the fifth / sixth speed shift rod 14, and a substantially central portion of an inversion lever 18 swings on the sleeve 17 via a pin 19. It is movably supported. A groove 18a similar to the shift operation groove 11c is provided on one end of the rotation lever 18 on the rotation / sliding head 16 side, and the other end on the shift head portion 15b side is engaged with the shift operation groove 15c. A mating ball-shaped connecting portion 18b is provided.

The shift operation grooves 11c, 12c, 13c and the groove 18a are aligned in one row in the vertical direction at the time of neutral, as shown in FIG.

The rotary / sliding head 16 has the structure shown in FIGS.
, The shift head portions 11b, 12b, 13
The shift operation grooves 11c and 12 are provided on the peripheral surface on the side facing b and the like.
A shift operation protrusion 16a is provided so as to engage with any one of c, 13c and the groove 18a so as to be engageable and disengageable. Further, a projection 16c having a connection recess 16b is provided on the upper peripheral surface of the rotary / sliding head 16 so as to project. This connecting recess 16b
By fitting the end portion 20a of the select / shift operation lever 20 processed into a substantially spherical surface, the rotary / sliding head 16 is rotated and slid by the select / shift operation lever 20.

A circumferential groove 10a, into which a lock ball 22 biased by a spring 21 is removably engaged, is formed on the circumferential surface of the shift rod 10 at one end side (rear end side) in the axial direction. A plurality (three in FIG. 1) are provided, and the spring 21, the lock ball 22 and the peripheral groove 10a constitute a shift positioning and shift reaction force receiving mechanism. Thus, by providing the shift rod 10 with the circumferential groove 10a, each shift fork 1
The shift positioning and shift reaction force receiving mechanism which can be commonly used for 1, 12, 13 and 14 can be configured. The spring 21 and the lock ball 22 are supported on the rear end side of a device case (not shown).

Although not shown, the shift mechanism of the transmission configured as described above has unselected shift forks 11, 12, 13 and 1 in order to prevent double meshing.
An interlock member for restraining 5 is provided.
Although not shown, the select / shift operation lever 20
Is equipped with a positioning mechanism for positioning the rotary / sliding head 16 in the rotational direction during a select operation.

Next, the gear select / shift operation by the shift mechanism of the transmission of this embodiment will be described.

At the time of neutral, the rotary / sliding head 16 (shift rod 10) is rotated by the select / shift operating lever 20 so that the shift operating projection 16a is moved to a desired gear stage, for example, as shown in FIG. The select operation is performed by engaging with the shift operation groove 12c of the second speed shift head portion 12b. Next, when the select / shift operating lever 20 is operated in this state to move the rotary / sliding head 16 in the axial direction, the first and second speed shift forks 12 move relative to the shift rod 10. And shift operation is performed. After the shift operation, the shift fork 12 (shift rod 10) is maintained in the shift position by the engagement of the lock ball 22 and the circumferential groove 10a. As a result, the sleeve (not shown) fitted to the tip of the shift fork 12 moves, and the hub splined to the output shaft meshes with the driven gear of the first speed or the second speed.

When shifting to fifth speed or sixth speed,
After operating the rotary / sliding head 16 (shift rod 10) by the select / shift operating lever 20 to return to the neutral state, the rotary / sliding head 16 is rotated to engage the shift operating projection 16a with the groove 18a. To select. Next, when the select / shift operating lever 20 is operated in this engaged state to move the rotary / sliding head 16 in the axial direction, the inversion lever 18 rotates about the pin 19 as a fulcrum, and this rotary motion is performed. Is a connecting portion 18b of the inversion lever 18 and the shift operation groove 15
It is converted into a linear motion at the engaging portion with c, the shift fork 15 moves along the fifth and sixth speed shift rods 14,
A shift operation is performed. After the shift operation, the shift fork 15 is maintained in the shift position by the engagement of the lock ball 22 and the circumferential groove 10a. As a result, the sleeve (not shown) fitted to the tip of the shift fork 15 moves, and the hub splined to the output shaft meshes with the driven gear of the fifth speed or the sixth speed.

When shifting to the reverse speed, similarly, after returning to the neutral state, the rotary / sliding head 1
6 (shift rod 10) is rotated to shift operation protrusion 16
a is a shift operation groove 1 of the shift head portion 11b at the backward stage
Select operation is performed by engaging with 1c. Next, operate the select / shift operating lever 20 in this state,
When the rotary / sliding head 16 is moved in the axial direction, the reverse shift fork 11 moves relative to the shift rod 10 to perform a shift operation. After the shift operation,
The shift fork 11 (shift rod 10) is maintained in the shift position by the engagement of the lock ball 22 and the circumferential groove 10a. As a result, the sleeve (not shown) fitted to the tip of the shift fork 11 moves, and the hub splined to the output shaft meshes with the reverse driven gear.

According to the above embodiment, the shift rod 10
The reverse shift fork 11, the first and second speed shift forks 12 and the third and fourth speed shift forks 13 are supported by the shift forks 11, 12, and 1 respectively.
3 is operated by a rotary / sliding head 16 fixedly mounted on the shift rod 10, a 5th and 6th speed shift fork 15 is mounted on a shift rod 14 parallel to the shift rod 10, and an inversion lever 18 is provided. Shift fork 1 by rotating / sliding head 16 via
5, the peripheral groove 1 provided on the shift rod 10 with which the lock ball 22 is removably engaged.
0a allows all shift forks 11, 12, 13
And 15 are positioned, the number of parts is greatly reduced and the weight is reduced as compared with the conventional shift mechanism shown in FIG. 4 in which a shift rod, a lock ball, etc. are arranged for each shift fork. Even if it is accommodated in a cylindrical transmission case, it is not necessary to extend the shift rod to support it at both ends in the axial direction of the transmission case, and the problem of weight increase does not occur.

Further, the peripheral groove 10 provided in the shift rod 10
All shift forks 11, 12, in one place by a
Since 13 and 14 are positioned and the inversion lever 18 is swingably provided on the shift rod 14 side, even if the transmission case is made of aluminum, the transmission case and the iron-based metal material are used. The shift feel is less affected by the difference in coefficient of thermal expansion between the shift mechanism and the shift mechanism, and there is no fear that the operation feeling will deteriorate.

In the above embodiment, the fifth and sixth speed shift forks 1 in which the reverse rod, the first and second speeds, and the third and fourth speed shift forks 11, 12 and 13 are mounted on the shift rod 10.
5 is mounted on the shift rod 14 parallel to the shift rod 10, but the present invention is not limited to this.
All shift forks 11, 12, 13 and 14 may be equipped on the shift rod 10.

[0025]

As described above, according to the present invention, the equipment case is provided with the shift rod in the rotational and axial directions, and the shift rod is provided with the shift fork of each shift stage having the shift head portion. The shift rod is provided so as to be slidable in the axial direction, and the shift rod has a shift operation projection that is disengageably engaged with a shift operation groove provided in the shift head portion. Since the rotary / sliding head is fixed, a circumferential groove with which the lock ball urged by the spring provided on the equipment case is engaged is provided at a predetermined position in the axial direction of the shift rod. Even if it is housed in a cylindrical transmission case, there is no risk of weight increase, and it is possible to reduce the weight, and it is also affected by the thermal expansion of the transmission case. Les is not.

[Brief description of drawings]

FIG. 1 is a plan view showing a shift mechanism of a transmission of the present invention with a part thereof omitted.

FIG. 2 is an enlarged perspective view of a rotary / sliding head portion.

FIG. 3 is an enlarged cross-sectional view showing the shift mechanism of FIG. 1 with a part thereof omitted.

FIG. 4 is a plan view of a conventional shift mechanism.

[Explanation of symbols]

 10, 15 Shift rod 10a Circumferential groove 11, 12, 13, 15 Shift fork 11c, 12c, 13c, 15c Shift operation groove 16 Rotating / sliding head 16a Shift operation protrusion 18 Inversion lever 20 Select shift operation lever 21 Spring 22 Rock ball

Claims (3)

[Claims] 1. A shift rod rotatably and axially movable in an equipment case is provided with a shift fork of each shift stage having a shift head portion slidably in the axial direction. The rod has a shift operation protrusion that is disengageably engaged with a shift operation groove provided in the shift head portion, selects a shift fork of each shift stage, and shifts, fixing a rotary / sliding head, Furthermore, a shift mechanism of a transmission characterized in that a peripheral groove with which a lock ball biased by a spring provided on the equipment case side is engaged is provided at a predetermined position in the axial direction of the shift rod. 2. The shift mechanism of the transmission according to claim 1, wherein the shift fork of each shift stage includes a reverse shift fork, first and second speed shift forks, and third and fourth speed shift forks. A shift fork and a fifth and sixth speed shift fork,
The fifth / sixth speed shift fork is not a shift rod but a fifth / sixth speed shift rod mounted in the equipment case in parallel with the shift rod so as to be movable in the axial direction thereof. And the shift mechanism of the transmission. 3. The shift mechanism of the transmission according to claim 2, wherein an inversion lever is rotatably supported by the fifth and sixth speed shift rods, and the rotation lever is provided at one end of the inversion lever. .Providing a groove with which the shift operation projection of the sliding head engages in a disengageable manner, and engaging the other end of the inversion lever with the shift operation groove of the fifth and sixth speed shift forks. The shift mechanism of the transmission characterized by.