JP3079458B2 - Selective sliding gear - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a selective sliding gear device applied to a transmission and the like of an automobile.

[0002]

2. Description of the Related Art FIG. 4 shows the structure of a conventional automobile transmission. In the figure, reference numeral 1 denotes a fixed gear, and the fixed gear 1 is fixed to a first rotating shaft 2. Also, code 3
Is a sliding gear that selectively meshes with the fixed gear 1.
The sliding gear 3 is provided on a second shaft 4 disposed in parallel with the first rotating shaft 2 via a bearing 5 so as to be slidable in the axial direction. The fixed gear 1 and the sliding gear 3 constitute a selective sliding gear mechanism capable of selecting a predetermined gear.

In this selective sliding gear mechanism, a fixed gear 1
And the sliding gear 3 can be easily engaged with each other,
At the tooth end faces of both gears 1 and 3 facing each other at the start of meshing,
A chamfer (chamfered part) is provided.

FIG. 5 shows an example of a gear provided with a chamfer. FIG. 6 shows an enlarged view of the end face of the tooth portion. This example is described in Japanese Utility Model Laid-Open No. 3-17452,
On the end face of each tooth 8 of the gear 7, a chamfer 11 consisting of a pair of faces (referred to as “chamfer faces”) 10 and 10 inclined from the center in the thickness direction toward the tooth faces 9 and 9 on both sides. Is formed. Reference numeral 12 denotes a chamfer ridge line, which is formed in a straight line here. Further, what is indicated by α is the chamfer angle. The chamfer angle α is an intersection angle between the two chamfer surfaces 10 and 10, and is defined as an intersection angle on a cylindrical surface including a pitch circle of the gear 7, for example.

[0005] By providing such a chamfer 11, when the gears start meshing with each other, a pushing force acts to automatically adjust the phase of the gears, so that the two gears can easily mesh with each other.

[0006]

By the way, there is a demand for further reducing the chamfer angle in order to increase the pushing force at the time of meshing.

However, if the chamfer angle is reduced, the effective tooth width is reduced when the entire tooth width is constant, resulting in a reduction in strength.

On the other hand, if the chamfer angle is reduced while securing the effective tooth width so that the strength does not decrease, the entire tooth width must be increased, resulting in an increase in space.

SUMMARY OF THE INVENTION The present invention has been made in view of such a conventional problem, and can always generate an effective pushing force, without increasing the overall tooth width and reducing the effective tooth width. It is an object of the present invention to provide a selective sliding gear device that does not need to be provided.

[0010]

SUMMARY OF THE INVENTION The present invention comprises a fixed gear,
A sliding gear that is slid in the axial direction and selectively meshes with the fixed gear; and at both ends of the tooth end faces of the two gears facing each other at the start of meshing, from substantially the center in the tooth thickness direction of the tooth end faces. In the selective sliding gear mechanism in which a chamfer formed of a pair of surfaces inclined toward the tooth surface of the chamfer is formed, the ridge line of the chamfer is formed in a convex curve shape, and the root portion of the chamfer is substantially aligned with the axis of the gear. The above problem has been solved by cutting at orthogonal planes.

[0011]

As a structure for reducing the chamfer angle without increasing the overall tooth width and without reducing the effective tooth width, as shown in FIG. It is conceivable to cut on a plane perpendicular to the axis of the arrow. In the figure, reference numeral 14 denotes a cut surface.

In this case, if there is no manufacturing error of the chamfer ridge line 12 of both gears, the chamfer ridge line 12 does not hit the cut surface 14, as shown in FIG. 8, and a pushing force is effectively generated.

However, in reality, the angles of the straight chamfer ridge lines 12 of the two gears may be slightly different due to manufacturing errors, as shown in FIG. When hitting the surface 14, there is a possibility that the pushing force is not effectively generated.

In the selective sliding gear device of the present invention,
Since the chamfer ridge line is formed in a convex curve shape, the chamfer ridge lines come into point contact with each other, and it is possible to prevent the chamfer ridge line from hitting the first cut portion due to a manufacturing error of the chamfer ridge line.

Further, since the root portion of the chamfer is cut as described above, the overall tooth width is not increased.
In addition, the chamfer angle can be reduced without reducing the effective tooth width.

[0016]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a side view of a main part of a selective sliding gear device of an embodiment, FIG. 2 is an enlarged side view of a tooth portion of a gear of the gear device,
FIG. 3 is a plan view of the teeth as viewed from above.

In FIG. 1, reference numeral 21 denotes a fixed gear, which is fixed to a first rotating shaft 22. 23 is a sliding gear,
A second rotating shaft (not shown) is provided slidably in the axial direction.

As shown in FIG. 3, each tooth 24 is provided on an end face of each tooth 24 facing each other when the gears 21 and 23 start meshing with each other.
A chamfer 27 is formed of a pair of chamfer surfaces 26, 26 inclined from the substantially center of the end surface in the tooth thickness direction toward the tooth surfaces 25, 25 on both sides. Each chamfer surface 2
Each of the chamfer ridges 28, 26 has a convex curved surface bulging slightly convex, and the chamfer ridge 28 formed by the intersection of the chamfer surfaces 26, 26 is formed in an arc shape.

The center of curvature O of the chamfer ridge line 28 is
When the teeth of the gears 21 and 23 are engaged with each other, the positions are set such that the substantially middle portions of the chamfer ridge line 28 first come into contact with each other.

Further, a cut surface 29 as shown in FIGS. 2 and 3 is provided at the root of the chamfer 27 which is not involved in the generation of the pushing force. This cut surface 29 is
It is constituted by a plane orthogonal to the axes 1 and 23.

The curvature R of the chamfer ridge line is related to the cut amount of the cut surface 29, and the condition (small curvature) that the substantially middle portions of the chamfer ridge line 28 always come into contact with each other first regardless of manufacturing variations and the like. Is satisfied, and the curvature is made as large as possible. This is because, when the curvature becomes smaller, if the initial contact position is shifted to the cut surface side due to the variation, the substantial chamfer angle becomes larger and a sufficient pushing force cannot be obtained.

Although the effective tooth width is sufficiently secured by the presence of the cut surface 29, the chamfer angle α1 is set smaller than the conventional chamfer angle α2, but the entire tooth width is kept within a predetermined dimension. Have been. In FIG. 3, a conventional chamfer is indicated by a dotted line.

Next, the operation will be described.

In this gear mechanism, the gears 21 and 23
Since the chamfer ridge line 28 provided on the end surface of the tooth portion is formed in an arc shape, even if there is a slight error in the shape and the like of the chamfer ridge line 28, the point contact with each other first occurs at any place of the chamfer ridge line 28 Therefore, there is no possibility that the chamfer ridge line 28 first hits the cut surface 29.
Further, since the cut surface 29 is provided at the root of the chamfer 27, the chamfer angle can be reduced without reducing the effective tooth width and without increasing the overall tooth width. Therefore, as a result, the pushing force can be effectively generated.

[0026]

As described above, according to the selective sliding gear device of the present invention, since the root of the chamfer provided on the end face of the tooth portion of the gear is cut, the overall tooth width is increased. The chamfer angle can be reduced without reducing the effective tooth width. In addition, although the tooth root is cut, the chamfer ridge line is formed in a convex curve, so that the chamfer ridge line comes into point contact, and it is possible to prevent the chamfer ridge line from first hitting the cut portion due to a manufacturing error. it can. As a result, a pushing force can be generated effectively, and the meshing can be facilitated.

[Brief description of the drawings]

FIG. 1 is a side view of a main part of an embodiment of the present invention.

FIG. 2 is an enlarged side view of a tooth portion of the gear according to the embodiment of the present invention.

FIG. 3 is an enlarged plan view of a tooth portion of the gear according to the embodiment of the present invention.

FIG. 4 is a side view of a transmission including a conventional selective sliding gear mechanism.

FIG. 5 is a perspective view showing an example of gears of a conventional selective sliding gear mechanism.

FIG. 6 is an enlarged perspective view of a tooth end surface portion of the gear.

FIG. 7 is a view showing an expected improvement of the end face of the tooth portion of FIG. 6;

FIG. 8 is a side view showing an ideal meshing state of the gear having the tooth end surface structure of FIG. 7;

9 is an exaggerated side view showing a realistic meshing state of the gear having the tooth end surface structure of FIG. 7;

[Explanation of symbols]

 21: fixed gear 23: sliding gear 24: tooth 25: tooth surface 26: surface 27: chamfer 28: chamfer ridge line 29: cut surface

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F16H 55/00-55/30 F16H 3/38

Claims (1)

(57) [Claims] 1. A fixed gear, and a sliding gear that is slid in the axial direction and selectively meshes with the fixed gear. In a selective sliding gear device in which a chamfer including a pair of surfaces inclined from a substantially center in a tooth thickness direction of an end face toward both tooth surfaces is formed, a ridge line of the chamfer is formed in a convex curve shape, and a chamfer of the chamfer is formed. A selective sliding type gear device, characterized in that a tooth root portion is cut at a plane substantially orthogonal to an axis of a gear.