JPH06330992A - Manual type transmission - Google Patents

Abstract

PURPOSE:To perform smooth switching to reverse by means of a light operation force by a method wherein a thin tooth part to provide an angular rotatable gap between a reverse input gear and the thin tooth part is formed at a reverse idler gear. CONSTITUTION:In switching to reverse, a reverse idler gear 7 is slid over a reverse idler shaft through a shift fork and brought into contact with a reverse input gear 4, the idler gear 7 having a low load performs angular rotation. A thin tooth part 7 is partially engaged with the tooth 41 of an input gear 4 and in a state that a specified gap S is provided between the thin tooth part 72 and the tooth 41 of the input gear 4, the thin tooth part being brought into contact with a reverse output gear 6. When the idler gear 7 is further moved in an axial direction, the idle gear 7 is rotated by an amount equivalent to the gas S based on the input gear 4 and started to engaged with the output gear 6. This constitution causes reduction of a shift operation force at the initial stage of engagement of the idler gear 7 with the output gear 6.

Description

Detailed Description of the Invention

[0001]

This invention relates to a manual transmission.

[0002]

2. Description of the Related Art Generally, this type of transmission is
For example, as shown in Japanese Utility Model Laid-Open No. 63-14061, a reverse idler gear having an annular groove into which a shift fork is fitted is supported by an idler shaft mounted on a transmission case so as to be movable in the axial direction. By providing a reverse input gear and a reverse output gear respectively on the input shaft and the output shaft installed on the transmission case, by meshing the reverse idler gear with the reverse input gear and the reverse output gear,
I am trying to switch to reverse.

[0003]

By the way, in the above transmission, when the vehicle is once stopped and the shift position is switched to reverse, the reverse idler gear is moved in the axial direction by operating the shift fork. , The reverse idler gear is first meshed with the reverse input gear on the input shaft, and then meshed with the reverse output gear on the output shaft to switch to reverse. At the time of meshing with, the chamfer provided at the end of the reverse idler gear is pressed against the chamfer of the reverse input gear, and the index torque generated by the pressure contact between these chamfers, that is, the torque that tries to rotate the gear The reverse input less impact than the gear said idler gear is angularly rotated, at the stage where the teeth of the gears is met, the reverse idler gear is to mesh with the reverse input gear. Further, due to the axial movement of the idler gear, the chamfer of the idler gear comes into pressure contact with the chamfer of the reverse output gear, and the reverse idler gear and the reverse output gear try to rotate due to the pressure contact of both chamfers. is there.

However, since the reverse output gear cannot be rotated by interlocking with the drive wheels via the output shaft, the reverse idler gear rotates angularly. Since the reverse input gear is already meshed, in order for the reverse idler gear to angularly rotate, the input shaft must also be angularly rotated through the reverse input gear, and the input shaft The drag resistance due to the inertial force of the clutch interposed between the input shaft and the engine, and the rotation resistance of the bearing that rotatably supports the input shaft on the transmission act on the. Therefore, in the initial stage of meshing the reverse idler gear with the reverse output gear, a large shift operation force is required to move the reverse idler gear in the axial direction, which causes a problem that the shift operation becomes heavy.

On the other hand, as schematically shown in FIG. 4, when the reverse idler gear B is moved in the axial direction by the operation of the shift fork A, the reverse idler gear B is moved.
Between the idler gear B and the idler shaft C that supports the gear B, frictional resistance occurs at points indicated by arrows Ta, Tb, and Tc in FIG. In order to angularly rotate the idler gear C due to the pressure contact with the chamfer, a large force that can resist the frictional resistance is required, and there is also a problem that the shift operation becomes heavy as a whole.

The present invention was developed in view of the above circumstances, and an object of the present invention is to provide a transmission in which switching to reverse can be smoothly performed with a light operating force.

[0007]

According to the invention described in claim 1, the reverse output gear 6 is provided at the end portion of the teeth of the reverse idler gear on the side of the reverse input gear.
A thin tooth portion 72 is provided between the tooth 41 of the reverse input gear 4 and the tooth 41 of the reverse input gear 4 to form a gap S that allows the reverse idler gear 7 to angularly rotate with respect to the reverse input gear 4. It is characterized by that.

According to a second aspect of the present invention, the reverse idler gear 7 is fitted in the annular groove 7 with which the shift fork SF is engaged.
0, and includes a sleeve portion 7a that is supported axially freely on the idler shaft 3 and a gear portion 7b that meshes with the reverse input gear 4 and the reverse output gear 6, and the gear portion 7b is formed by the sleeve portion 7a. It is characterized by being rotatably supported via a bearing 7C.

[0009]

According to the first aspect of the invention, the shift fork S is used when the transmission is switched to reverse.
When the reverse idler gear 7 is slid with respect to the reverse idler shaft via F and the reverse idler gear 7 is first brought into contact with the reverse input gear 4, the reverse idler gear 7 with a small load is angularly rotated. The thin-walled tooth portion 72 partially meshes with the tooth 41 of the reverse input gear 4, and the thin-walled tooth portion 7
The thin tooth portion 72 abuts the reverse output gear 6 in a state in which a constant gap S is opened between the tooth 2 of the reverse input gear 4 and the tooth 41 of the reverse input gear 4. When the reverse idler gear 7 is further moved in the axial direction by operating the shift fork F, the reverse idler gear 7 is moved.
However, the reverse idler gear 7 starts to mesh with the reverse output gear 7 by rotating the reverse input gear 4 and the input shaft 1 by the gap S, and thus the reverse idler gear 7 is The shift operation force in the initial stage of meshing with the reverse output gear 6 can be smaller than in the conventional case.

At the time of completion of meshing of the reverse idler gear 7 with the reverse input gear 4 to the reverse output gear 6, the reverse idler gear 7 is
The thick portion of the tooth 71 of the reverse input gear 4 and the tooth 61 of the reverse output gear 6 are
, And the switch to reverse is reliably performed.

According to the second aspect of the present invention, when the reverse idler gear 7 is moved by operating the shift fork SF, it is interposed between the reverse idler gear 7 and the idler shaft 3 supporting the gear 7. Even if friction resistance occurs due to sliding of the reverse idler gear with respect to the idler shaft 3, the gear portion 7b can freely rotate with respect to the sleeve portion 7a via the bearing 7c. And the reverse input gear 4
Also, the meshing with the reverse output gear 6 is performed regardless of the frictional resistance, and therefore, the meshing of the gear portion 7b with the reverse input gear 4 and the reverse output gear 6 becomes smooth.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 3 shows an essential part of a manual transmission mounted on an automobile. In a transmission case T, an input shaft 1 for interlocking with an engine and an output shaft 2 for interlocking with driving wheels are shown. And rotatably supported by bearings 11 and 21, respectively, and between the input shaft 1 and the output shaft 2 both shafts 1 and
An idler shaft 3 extending in parallel with 2 is installed.

The input shaft 1 has a small-diameter input gear 12 and a large-diameter input gear 1 for advancing.
3 is integrally formed, and a reverse input gear 4 is integrally formed between the small diameter input gear 12 and the large diameter input gear 13 in the shaft 1.

The output shaft 2 rotatably supports a first output gear 22 meshing with the small diameter input gear 12 and a second output gear 23 meshing with the large diameter input gear 13. The synchronous meshing device 5 is assembled between the output gears 22 and 23.

The synchronous meshing device 5 has a known structure, and includes a clutch hub 51 spline-coupled to the output shaft 2 and a clutch assembled around the outer periphery of the clutch hub 51 by spline fitting so as to freely move in the axial direction. A sleeve 52 and a pair of synchronizer rings 53 that are loosely inserted in the clutch cones 22a and 23a provided in the output gears 22 and 23 are provided, and the clutch sleeve 52 is moved by the axial direction.
Mesh with the gear splines 22b and 23b provided on the output gears 23 and 22, respectively, and one of the output gears is operatively connected to the output shaft 2 via the clutch sleeve 52 and the clutch hub 51. While the shift gear can be switched to a predetermined gear, the reverse output gear 6 is attached to the clutch sleeve 52.
Are integrally formed.

A reverse idler gear 7 is supported on the idler shaft 3 so as to be freely movable in the axial direction and rotatable.

With the above construction, in the embodiment, the reverse idler gear 7 is connected to the shift fork S.
A sleeve portion 7a, which has an annular groove 70 with which F is engaged, is supported on the idler shaft 3 so as to be freely movable in the axial direction, and a gear having teeth 71 that mesh with the reverse input gear 4 and the reverse output gear 6 on the outer periphery. The gear portion 7b is rotatably supported by the sleeve portion 7a via a bearing 7c formed of a ball bearing.

Further, as schematically shown in FIG. 2, the teeth 41 and the teeth 4 of the reverse input gear 4 are provided at the ends of the teeth 71 of the gear portion 7b on the side of the reverse input gear.
The reverse output gear 6 is thinner than the interval L of 1 and
And a tooth 41 of the reverse input gear 4 when engaging with a thin-walled tooth portion 72 that forms a gap S that allows the reverse idler gear 7 to angularly rotate with respect to the reverse input gear 4. A chamfer 7 is provided at an end of the thin tooth portion 72 on the side of the reverse input gear.
3 is formed.

In the figure, reference numeral 42 denotes a chamfer formed at the end portion of the teeth 41 of the reverse input gear 4 on the side of the reverse idler gear, and 62 indicates the end portion of the teeth 61 of the reverse output gear 6 on the side of the reverse idler gear. It is the formed chamfer.

Thus, in order to switch the transmission having the above configuration to reverse, the shift fork SF
The reverse idler gear 7 is moved to the left in FIG. 3 via the so that the reverse idler gear 7 is first meshed with the reverse input gear 4.
Due to the movement of the reverse idler gear 7, the chamfer 73 formed on the tooth 71 comes into contact with the chamfer 42 of the tooth 41 of the reverse input gear 4, and the action of these both chamfers 73, 42 causes the reverse idler gear 7 with a small load to be actuated. 2, the gear portion 7b of the reverse idler gear 7 partially rotates with the tooth 41 of the reverse input gear 4 as shown in FIG. Along with
The thin tooth portion 72 and the tooth 4 of the reverse input gear 4
The chamfer 73 of the thin tooth portion 72 abuts on the chamfer 62 of the tooth 61 of the reverse output gear 6 in a state in which a constant gap S is formed between the chamfer 73 and the gear tooth 1.

When the reverse idler gear 7 is further moved in the axial direction by operating the shift fork F from such a state, the reverse idler gear 7 and the reverse output gear 6 are about to rotate. The reverse output gear 6
Means that the reverse idler gear 7 is angularly rotated because it is interlocked with the driving vehicle through the output shaft 2 and cannot rotate, and when the reverse idler gear 7 is angularly rotated, as described above. Since a constant gap S is opened between the thin tooth portion 72 and the tooth 41 of the reverse input gear 4, the reverse idler gear 7 is the reverse input gear 4 by the gap S. Rotating with respect to the reverse input gear 4 and the input shaft 1 as in the prior art.
Does not rotate at the same time, and therefore, the shift operation force at the initial stage of meshing the reverse idler gear 7 with the reverse output gear 6 is smaller than the conventional one, and the overall operation is smooth with a light operation force. You can

When the reverse idler gear 7 is completely meshed with the reverse input gear 4 to the reverse output gear 6, the thick portion of the tooth 71 of the reverse idler gear 7 is the tooth 41 of the reverse input gear 4. Teeth 6 of reverse output gear 6
It is possible to surely switch to reverse by meshing with 1, and it is possible to secure sufficient strength at the time of meshing.

When the reverse idler gear 7 is moved by the operation of the shift fork SF, the idler shaft of the reverse idler gear 7 is interposed between the reverse idler gear 7 and the idler shaft 3 supporting the gear 7. Although frictional resistance is generated due to sliding with respect to No. 3, the gear portion 7b is not supported by the bearing 7 with respect to the sleeve portion 7a.
Since the gear 7b is meshed with the reverse input gear 4 and the reverse output gear 6 independently of the frictional resistance, the reverse input gear of the gear 7b can be rotated. 4 and the reverse output gear 6 mesh smoothly.

[0024]

As described above, according to the first aspect of the present invention, when the transmission is switched to reverse, the reverse idler gear 7 is thrust with respect to the reverse idler shaft via the shift fork SF. First, when the reverse idler gear 7 comes into contact with the reverse input gear 4, the reverse idler gear 7 having a small load is angularly rotated, and the thin tooth portion 72 partially meshes with the tooth 41 of the reverse input gear 4. In addition, the thin-walled tooth portion 72 contacts the reverse output gear 6 in a state where a constant gap S is opened between the thin-walled tooth portion 72 and the tooth 41 of the reverse input gear 4, and the shift fork further moves. When the reverse idler gear 7 is moved by operating F, the reverse idler gear 7 The reverse idler gear 7 starts to mesh with the reverse output gear 7 by rotating the reverse input gear 4 and the input shaft 1 by the gap S. Therefore, the reverse idler gear 7 is connected to the reverse output gear 7. The shift operation force at the initial stage of meshing with the reverse gear 6 may be smaller than in the conventional case, and at the time of completion of meshing of the reverse idler gear 7 with the reverse input gear 4 to the reverse output gear 6, the reverse idler The thick portion of the tooth 71 of the gear 7 meshes with the tooth 41 of the reverse input gear 4 and the tooth 61 of the reverse output gear 6 so that the switching to the reverse can be reliably performed.

According to the second aspect of the present invention, when the reverse idler gear 7 is moved by operating the shift fork SF, it is provided between the reverse idler gear 7 and the idler shaft 3 supporting the gear 7. Even if friction resistance occurs due to sliding of the reverse idler gear with respect to the idler shaft 3, the gear portion 7b can freely rotate with respect to the sleeve portion 7a via the bearing 7c. And the reverse input gear 4
Also, the meshing with the reverse output gear 6 is performed regardless of the frictional resistance, and therefore, the meshing of the gear portion 7b with the reverse input gear 4 and the reverse output gear 6 becomes smooth.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view of a main part of a transmission according to the present invention.

FIG. 2 is an operation explanatory view of the transmission according to the present invention.

FIG. 3 is a sectional view of a main part of a transmission according to the present invention.

FIG. 4 is a schematic explanatory diagram of a main part of a conventional transmission.

[Explanation of symbols]

 1 Input Shaft 2 Output Shaft 3 Idler Shaft 4 Reverse Input Gear 41 Teeth 6 Reverse Output Gear 7 Reverse Idler Gear 70 Annular Groove 71 Teeth 72 Thin-walled Teeth 7a Sleeve 7b Gear 7c Bearing SF Shift Fork S Gap

Claims (2)

[Claims] 1. A shift fork (S) for interlocking a reverse idler gear (7), which is supported on an idler shaft (3) so as to freely move in an axial direction, with the reverse idler gear (7).
F) is operated to move in the axial direction to mesh with the reverse input gear (4) on the input shaft (1) and then mesh with the reverse output gear (6) on the output shaft (2), In a manual transmission that was switched to reverse,
When the reverse output gear (6) is meshed with the end of the teeth (71) of the reverse idler gear (7) on the side of the reverse input gear, between the teeth (41) of the reverse input gear (4). A manual transmission characterized in that the reverse idler gear (7) is provided with thin-walled teeth (72) forming a gap (S) that allows angular rotation with respect to the reverse input gear (4). 2. A shift fork (S) for interlocking a reverse idler gear (7) supported on an idler shaft (3) so as to be freely movable in an axial direction.
F) is operated to move in the axial direction so that the reverse input gear (4) on the input shaft (1) meshes with the reverse output gear (6) on the output shaft (2) to switch to reverse. In the manual transmission, the reverse idler gear (7) is connected to the shift fork (SF).
A sleeve portion (7) which has an annular groove (70) engaged with the idler shaft (3) and is supported by the idler shaft (3) so as to freely move in the time direction.
a) and a gear portion (7b) meshing with the reverse input gear (4) and the reverse output gear (6), and the gear portion (7b) is connected to the sleeve portion (7).
A manual transmission characterized by being rotatably supported by a) via a bearing (7c).