JPH08312675A - Gear with dog clutch for transmission - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a gear with a dog clutch for a transmission that can significantly reduce the manufacturing cost as compared with machining, and that does not easily cause gear disengagement. [Structure] A gear 1 with a dog clutch, in which dog teeth are provided on one side wall 2a side of a speed change gear 2 at circumferential intervals.
Is integrally formed by precision forging, and each dog tooth 4 is provided with a slit 5 on the back side thereof to be separated from the side wall 2a of the transmission gear 2 to be independent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a gear with a dog clutch in a transmission of an automobile.

[0002]

2. Description of the Related Art Conventionally, this type of gear with a dog clutch has been generally manufactured by cutting by machining. However, it takes time and effort to manufacture by machining,
Since the manufacturing cost becomes high, it has recently been proposed that the cost be reduced by integrally forming by cold forging or the like and omitting the finishing process of the tooth surface of the dog clutch.

It should be noted that in the prior art, the utility model of Japanese Utility Model Publication No. 1-174636
Although there is a gear with a dog clutch described in Japanese Patent Laid-Open Publication No. JP-A-2003-264, this has a structure in which a pawl tooth (also referred to as a dog tooth) provided on one side surface of a transmission gear is integrally formed by cold forging.

[0004]

However, the dog clutch gear described in the above publication has room for improvement in the following points. That is, since the dog teeth are integrally formed by cold forging, there is no need to finish the tooth surface,
There is an advantage that the cost can be reduced. On the other hand, Fig. 5 (a)
Since the back surface of the dog tooth 21 is continuously provided to the one side wall surface 23 of the speed change gear 22 as shown in (b), the inner tooth 24 of the sleeve (FIG. 5C) and the dog tooth 21 of the dog clutch are When the load (mainly the rotation torque) acting on one of the teeth changes in the meshed state, as shown in FIG.
The distal end side of the dog tooth 21 flexes more than the rear side, and the inner tooth 24 of the sleeve is easily removed. This is because the rear surface of the dog tooth 21 is continuously provided on the side wall surface 23 of the transmission gear 22, so that the rigidity on the rear surface side is higher than that on the distal end side, and the distal end side of the dog tooth 21 is largely bent.

Further, when manufacturing a gear with a dog clutch by machining, it is necessary to provide a clearance (gap) for the cutting blade between the side wall of the speed change gear and the side wall of the speed change gear when machining the dog tooth. A space is inevitably provided between the rear side of the dog tooth and the side wall of the speed change gear from the viewpoint of processing.However, when the dog tooth is integrally formed by cold forging or the like, the dog tooth and the side wall of the speed change gear are separated. There is no gap between them, and the dog teeth are not separated from the side wall of the transmission gear, and it is difficult to form such a structure.

The present invention has been made in view of the above points, and an object of the present invention is to provide a gear with a dog clutch for a transmission, which can greatly reduce the manufacturing cost as compared with the manufacturing by machining, and in which gear disengagement does not easily occur. I am trying.

[0007]

In order to achieve the above object, a gear with a dog clutch according to the present invention comprises: a) a transmission having dog teeth on one side surface of the transmission gear at circumferential intervals. In the gear with dog clutch, b) the gear with dog clutch is integrally formed by forging, casting or sintering, and c) each dog tooth is separated from the transmission gear by providing a slit on the back side thereof. .

It is desirable that d) the bottom surface of the slit is deeper than the bottom surface of the dog tooth.

[0009]

According to the gear with dog clutch of the present invention having the above-mentioned structure, the whole gear is integrally formed by forging, casting or sintering, and the slits are partially formed, so that machining is unnecessary or almost unnecessary. The manufacturing cost is lower than that of the gear manufactured by conventional machining.
It can be reduced considerably. Also, each dog tooth that meshes with the inner teeth of the sleeve is separated (separated) from the speed change gear by the slit on the back side and is independent, so it acts on the dock teeth while meshing with the inner teeth of the sleeve. When the load changes, as shown in FIG. 4, the dog teeth are bent substantially evenly along the tooth width direction, so that the inner teeth of the sleeve do not accidentally come off, that is, so-called gear omission does not occur. Moreover, since the overall rigidity of the dog teeth is balanced, the durability is also improved and the shift state is stable for a long period of time.

According to the gear with dog clutch of the second aspect, since each dog tooth is completely separated from the portion of the transmission gear by the deeply dug slit, when the load on the dog tooth or the sleeve fluctuates. , The dock teeth and the sleeve are evenly bent as a whole, so that the gear disengagement is surely prevented.

[0011]

Embodiments of the dog clutch gear according to the present invention will be described below with reference to the drawings.

FIG. 1 (a) is a front sectional view schematically showing a dog clutch mechanism of a transmission having a dog clutch gear according to the present embodiment, and FIG. 1 (b) shows a part thereof. FIG. 2 is a cross-sectional plan view, FIG. 2 is a central sectional view in which the lower half of the dog clutch gear according to this embodiment is omitted, and FIG. FIG. 4 is an enlarged perspective view, and FIG. 4 is an explanatory view showing a mode of deformation (deflection) of the dog teeth and the sleeve inner teeth when the load changes in the gear with dog clutch of the present embodiment.

As shown in FIG. 1, the dog clutch mechanism A
Includes a dog clutch gear 1, a synchronizer / ring gear 11, and a sleeve 12. The gear 1 with a dog clutch is provided with a speed change gear 2 as a main gear on the entire circumference of one end portion, the opposite end portion is formed in a taper portion 3, and a ring gear 11 is arranged on the taper portion 3. Further, a large number of dog teeth 4 are provided at equal intervals in the circumferential direction at a substantially middle portion in the width direction of the gear 1 with dog clutch. In this example, the dog clutch gear 1 having such a structure is integrally formed by precision forging. Then, as shown in FIGS. 2 and 3, an annular slit 5 is cut over the entire circumference between the back side of the dog tooth 4 and one side wall 2a of the speed change gear 2 by machining using a lathe or the like. It Since it is formed by precision forging, it is not necessary to finish the tooth surfaces of the speed change gear 2 and the dog teeth 4
No machining is required, and it is used only to form the slit 5. This is because forming the slits 5 by machining after precision forging is more efficient, more productive, and has a better finish.

Further, in this example, the bottom surface of the slit 5 is deeper than the bottom surface of the dog tooth 4 [(r-r ')> as shown in FIG.
0] is dug down so that the dog tooth 4 is completely separated from the side wall 2a. Further, as shown in FIG. 3, a part of the dog teeth 4 formed by precision forging is left on the side wall 2a side of the speed change gear 2 slightly because the dog teeth 4 are cut away from the side wall 2a to facilitate the work. This is to prevent the side wall 2a from being scratched. Therefore, the side wall 2a
It is needless to say that the dog teeth 4 may not be left on the side wall 2a side by cutting along with the above. Further, the depth of the slit 5 may be slightly shallow so that the bottom surface of the slit 5 coincides with the bottom surface of the dog tooth 4.

The characteristic operation of the dog clutch gear 1 of the present embodiment having the above-described structure will be described.

When shifting the gear, when the sleeve 12 is moved to the left via a shift lever (not shown) in FIG. 1A, the dog tooth 4 and the sleeve inner tooth 12a are synchronized with each other by the synchronizer / ring gear 11. Mesh with each other. In this state, the gear shifting work is completed and the engine is driven at a predetermined reduction ratio. Then, when a load variation occurs in the dog teeth 4 by, for example, suddenly decreasing the rotation speed in the process of increasing the rotation speed of the engine, as shown in FIG. Since it flexes uniformly, almost no force acts on the inner teeth 12a of the sleeve in the direction of coming off.
Therefore, gear disengagement is prevented.

In the above embodiment, the case where the gear 1 with a dog clutch is integrally formed by precision forging has been described, but it is also possible to integrally form by cold forging or warm forging. Further, although the accuracy is lowered, it is possible to perform integral molding by casting. Furthermore, it is also possible to integrally form it by sintering, and in this case the slit 5 can be formed at the same time, so that machining can be completely omitted.

[0018]

As is apparent from the above description,
The gear with dog clutch of the transmission according to the present invention,
It has the following excellent effects.

(1) Since the entire gear is integrally formed by forging, casting or sintering and a slit is partially formed,
Machining is unnecessary or almost unnecessary, manufacturing costs can be reduced, and each dog tooth that meshes with the inner teeth of the sleeve is separated from the part of the speed change gear by a slit,
Since they are independent, when the load acting on the dog tooth fluctuates, the dog tooth flexes almost evenly along the tooth width direction, so gear disengagement does not occur, and the rigidity of the entire dog tooth Balance is achieved, and durability is improved.

(2) In the gear with dog clutch according to the second aspect, since each dog tooth is completely separated from the portion of the speed change gear by the deeply dug slit, the gear disengagement is surely prevented.

[Brief description of drawings]

FIG. 1 (a) is a front sectional view schematically showing a dog clutch mechanism of a transmission including a gear with a dog clutch according to an embodiment of the present invention, and FIG. 1 (b) is FIG. FIG. 4B is a cross-sectional plan view showing a part of the dog clutch mechanism of FIG.

FIG. 2 is a central sectional view in which a lower half of a dog clutch gear according to an embodiment of the present invention is omitted.

FIG. 3 is a partially enlarged perspective view showing a cross section of a gear with a dog clutch according to an embodiment of the present invention by cutting out a part thereof.

4] Deformation (deflection) of dog teeth and sleeve inner teeth when a load changes in the gear with dog clutch of the embodiment of the present invention.
It is explanatory drawing which shows a mode.

5 shows a conventional gear with a dog clutch by cold forging, FIG. 5 (a) is a central sectional view corresponding to FIG. 2, FIG. 5 (b) is a partially enlarged perspective view corresponding to FIG. FIG. 5C is an explanatory diagram corresponding to FIG.

[Explanation of symbols]

 1 Gear with dog clutch 2 Speed change gear 2a Side wall 4 Dog tooth 5 Slit 12 Sleeve 12a Internal tooth

Claims (2)

[Claims] 1. A gear with a dog clutch for a transmission, wherein dog teeth are provided on one side surface of the speed change gear at intervals in the circumferential direction, wherein the gear with the dog clutch is integrally formed by forging, casting or sintering. A gear with a dog clutch for a transmission, characterized in that each of the dog teeth is separated from the speed change gear by providing a slit on the back side thereof. 2. The gear with dog clutch for a transmission according to claim 1, wherein the bottom surface of the slit is deeper than the bottom surface of the dog tooth.