JPS6133321Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a constantly meshing transmission gear suitable for motorcycles and the like, and more particularly to the structure of a gear positioning circlip.

As shown in FIG. 1, which is a partial cross-sectional view, in a normally meshing transmission, a gear 2 that is spline-fitted to the input shaft 1 is connected to a gear 6 that is rotatably fitted to the outer periphery of the spline 5 of the output shaft 3. The pawl 9 of the dog clutch sliding part 7 (coupling sleeve), which is spline-fitted to the output shaft 3, fits into the recess 10 of the gear 6 to transmit power. There are multiple units installed in the transmission. When the sliding part 7 is slid by a shifter (not shown) and the pawl 9 is fitted into the recess 10, that is, when the dog clutch is connected, the rotational force is transferred from the input shaft 1 to the gears 2, 6,
It is transmitted to the output shaft 3 via the sliding part 7. In this clutch connecting operation, until the pawl 9 fits into the recess 10 (until the rotation angle positions of both coincide),
Since the claw 9 presses the end face of the gear 6 other than the recessed part 10,
A thrust is applied to the gear 6 toward the right in FIG. For this reason, in the conventional product, for positioning the gear 6, a circlip 12 shown in FIG. 2, which is a partial view in the direction of the arrows from FIG. It is beginning to accept the thrust. In the illustrated conventional example, a gear 15 rotatably fitted to the output shaft 3 contacts the gear 6 from the side opposite to the sliding portion 7, and the circlip 12 contacts the gear 7 via a rotation stopper washer 16. ing. 1st
As shown in FIG. 3, which is a partial view taken along the - arrow in the figure, the rotation stop washer 16 is provided with protrusions 17 at, for example, two locations on the inner circumferential edge thereof, which enter into the spline bottom side of the output shaft 3.

However, as shown in FIG. 1, the gear 6 with the recess 10 generally has a rim 18 on the outer periphery and a boss 19 on the inner periphery with teeth.
Since it is biased in the axial direction (for example, to the left in FIG. 1) relative to the Joins gear 6. On the other hand, a radial gap is formed between the boss 19 on the inner circumference of the gear 6 and the outer circumference of the output shaft 3 in order to prevent seizure. Therefore, if the length of the boss 19 in the axial direction is short, the gear 6 will fall in the direction of arrow F, which will deteriorate the tooth contact of the gears 2, 6 and reduce the durability of the tooth surfaces. A problem arises in that power transmission efficiency is also reduced. Furthermore, once the gear 6 is tilted, local wear occurs on the inner periphery of the boss 19 and the outer periphery of the output shaft 3, and the degree of tilt increases at an accelerating rate.

In order to solve the above problem, the length of the boss 19 in the axial direction may be increased. However, there is generally no margin for the length of the output shaft 3 or the transmission width, and if the boss 19 in FIG. 1 were extended toward the sliding part 7 without changing the length of the output shaft 3, for example A problem arises in that the sliding stroke of the sliding portion 7 toward the gear 6 (the depth of engagement between the pawl 9 and the recess 10 and the play stroke until the two engage) is insufficient. Therefore, in the structure shown in FIG. 1, it is impossible to lengthen the boss 19 without changing the length of the output shaft 3.

In other words, in the structure shown in FIG. 1, if the axial length of the boss 19 is increased to such an extent that the gear 6 does not fall, the length of the output shaft 3 will increase, and the length of each gear will correspondingly increase. The axial spacing and the length of the input shaft 1 increase. This causes problems such as an increase in the width and weight of the entire transmission, and
A problem arises in that the bending strength of

In order to solve the above problem, namely, axes 1 and 3
In order to increase the length of the boss 19 without increasing the length of the boss 19, the rotation stop washer 16 may be eliminated and the circlip 12 may be brought into direct contact with the gear 15. By doing so, the boss 19 can be extended by the thickness of the washer 16.

However, doing so causes the following problems. That is, in the above structure, when the gear 15 receives thrust from the sliding part 7 and comes into direct pressure contact with the circlip 12, the circlip 12 is pressed due to frictional force.
rotates on the output shaft 3 together with the gear 15, so that the edge 21 of the notch 20 of the circlip 12 shown in FIG. This may cause the problem of it jumping out.

This invention eliminates the conventional rotation stop washer and brings the circlip into direct contact with the end face of the gear, and also improves the structure of the circlip to prevent the circlip from falling off. That's right.

First, an example of a transmission to which the present invention is applied will be explained with reference to FIG. 4, which is a horizontal sectional view. The transmission shown in FIG. 4 is, for example, for a two-wheeled motor vehicle, and the input shaft 23 supported by a case 60 via a pair of bearings 61 and 62 has an end protruding from the bearing 61 to the right in FIG. (not shown) is connected to a crankshaft at the front of the vehicle body via a clutch. Gears a, b, c, d, e, and f are provided on the input shaft 23 in order from the shaft 61 side toward the bearing 62. Gear a is integral with output shaft 23, and gears b and e are rotatable with respect to output shaft 23. Gears c and d are integral with each other and are spline-fitted to the output shaft 23 so as to be able to freely slide in the axial direction, and are fitted into the recesses of gears b and e.
It is provided with pawls c', d' that can be fitted into b', e', and an annular groove 25 into which a shifter (not shown) is fitted.
The gear f is fitted onto the input shaft 23 so as not to be slidable in the axial direction.

The output shaft 26 is located behind the input shaft 23 and is supported by the case 60 via a pair of bearings 27 and 28. Output shaft 26 protrudes outward from bearing 28
An output sprocket 30 is attached to the left end in FIG. 4, and the sprocket 30 is connected to a sprocket on the rear wheel axle via a chain (not shown). Gears g, h,
i, j, k are attached in order from the bearing 27 side. Gear g meshes with gear a, and is rotatably fitted to output shaft 26 via bush 29. Gear h is meshed with gear b, and is slidably spline-fitted to the output shaft 26, and also has a pawl h'' that can fit into a recess g' of gear g and a recess i' of gear i. It has a pawl h' that can be formed and an annular groove 31 into which a shifter (not shown) fits.Gears i and j are rotatably attached to the tips of spline teeth 32 of the output shaft 26 while in contact with each other. The gear k is slidably spline-fitted to the output shaft 26, and has a pawl that can be fitted into the recess j' of the gear j.
k', a claw k'' that can be fitted into a recess ' of the gear, and an annular groove 33 into which a shifter (not shown) fits.The gear is fitted to the output shaft 26 via a bush 34, It cannot be slid in the axial direction.

A total of two circlips 35 and 36 according to the present invention are provided so as to fit into an annular groove 38 on the outer periphery of the output shaft 26 (gear shaft). The circlip 35 on the right side in FIG. 4 connects the boss end face 39 of gear i to gear j.
and are in direct contact from the opposite side. Circlip 3
6 is in direct contact with the boss end face 40 of gear j from the opposite side to gear i. The circlip 37 is a conventional product and directly contacts the boss end face 41 of the gear from the side opposite to the bearing 28.

In FIG. 5, which is an enlarged partial view taken along the line V-V in FIG.
is the bottom of the annular groove 38 into which it is slidably fitted in the rotational direction. As is clear from FIG. 5, the depth D of the groove 38 is smaller than the height H of the spline tooth 32.
Therefore, the root portion 50 of the spline tooth 32 remains radially inward from the bottom 47. Reference numeral 51 denotes a spline tooth bottom formed between two adjacent tooth roots 50, 50, and a radially inward protrusion 52 that fits into the bottom 51 is provided at one (or multiple) locations on the inner peripheral edge 48 of the circlip. are integrally formed. The circlip 35 is divided by a notch 53 formed in a portion diametrically opposed to the protrusion 52, and the edges 55 on both sides of the notch 53 are used to attach a circlip attachment/detachment tool (expansion tool). A recess 56 is provided. Further, the positions of the protrusion 52 and the notch 53 relative to the spline tooth 32 on the circumference of the circlip are set so that the notch 53 is located radially outward of the spline tooth bottom portion 51. Furthermore, the distance S in the circumferential direction between the protrusion 52 and the root portion 50 is set small, so that even if the circlip 35 rotates by the distance S as described later, the edge 55 of the notch 53 will not touch the spline tooth side surface 57. It is designed so that it does not get caught (it stops in front of the side surface 57). Circlip 35 shown
The radial width W increases from the notch 53 side to the protrusion 52 side, and only the end near the notch 53 is extended radially outward compared to the adjacent portion. Note that instead of the depression 56, a hole for mounting a tool or the like may be provided in the vicinity of the notch 53. The circlip 36 shown in FIG. 4 has a similar structure to the circlip 35 described above.

From the neutral state shown in Figure 4, shift to gear k using the shifter.
(Dog clutch sliding part) is slid to the right in Fig. 4 and the pawl k' is fitted into the recess j', the gears d, j, k
Power is transmitted from the input shaft 23 to the output shaft 26 via. Also, when gear k is slid to the left in Fig. 4, or when gear h, gears c, and d are slid to the left or right, different gear trains can be selectively used. Power is transmitted and gear changes are performed.

As described above, in the operation of fitting pawl k' of gear k into recess j', the operational force from the shifter causes pawl k' to shift into gear until the rotation angle positions of pawl k' and concave j' match and they fit together. The circlip 35 presses the end surface of j other than the recess j', and the circlip 35 receives a thrust corresponding to the pressing force from the gear j via the gear i. In that case, gear i
is meshed with gear c and constantly rotates on output shaft 26, so a frictional force corresponding to the thrust acts between gear i and circlip 35, causing circlip 35 to rotate together with gear i. However, the circlip 35 shown in FIG. 5 rotates only by a very small angle corresponding to the gap S between the rotation stopper projection 52 and the tooth base 50, and the edge 55 of the notch 53 is just before it catches the tooth side surface 57. Since it is stationary, the circlip 35 is not expanded and the output shaft 2
It doesn't jump out from 6.

The circlip 36 of FIG. 4 functions in the same manner as described above when fitting the pawl h' into the recess i'. The circlip 37 receives almost no thrust and positions the gear without jumping out from the output shaft 26.

According to the structure of the present invention described above, for example, the circlip 35 is in direct contact with the end face of the gear to be positioned i, and a rotary stop washer unlike the conventional one is not used, so the length of the output shaft 26 is increased. The inner circumferential bosses of the gears i and j can be extended in the axial direction by the thickness of the conventional rotation stop washer without causing the rotation stopper. Therefore, the gears i and j can be stably supported by the output shaft 26 and can be prevented from falling down.
Therefore, it is possible to improve the tooth contact of gears i, c and gears j, d, increase the durability of the tooth surfaces, and improve power transmission efficiency.

Furthermore, even if the axial dimension of the inner circumferential boss of gears i and j is set long enough to prevent the above-mentioned collapse, the dimension of the output shaft 26 can be set short, and the axial distance between each gear can be set accordingly. and the dimensions of the input shaft 23 can be set short. The overall size and weight of the transmission can therefore be reduced. Further, it is possible to prevent the bending strength of the shafts 23 and 26 from decreasing. The structure of the circlips 35 and 36 is simple, and the unit price is almost the same as that of conventional products, so it is possible to reduce the cost by eliminating the rotation stop washer.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view of the conventional example, FIGS. 2 and 3 are partial views taken along the - and - arrows in FIG. 1, respectively, FIG. 4 is a horizontal sectional view of the embodiment of the present invention, and FIG. Figure 4 is an enlarged partial view in the direction of the arrows. 26... Output shaft (gear shaft), 32... Spline tooth, 35, 36... Circlip, 38... Annular groove, 39, 40, 41... End surface, 48... Inner peripheral edge, 51... Spline tooth bottom , 52...protrusion,
53...Notch, a, b,...,...gear, D...
...Annular groove depth, H...Spline tooth height.

Claims (1)

[Scope of utility model registration request] In a transmission gear that changes speed by selectively using several sets of gear trains by engaging and connecting the corresponding dog clutches, a circlip for positioning the gear that receives the frustration force when the dog clutches are connected is fitted into an annular groove on the outer periphery of the gear shaft. , the circlip is brought into direct contact with the end surface of the gear to be positioned, the depth of the annular groove is made smaller than the height of the gear shaft spline teeth, and a rotation stopper protrusion that fits into the spline bottom is provided on the inner peripheral edge of the circlip, A transmission gear support device characterized in that a notch in the circlip is provided radially outward at the bottom of the spline.