JP2001248729A - Shift fork - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shift fork allowing the selection of the quality of a wear resistant member in a wider range, the reduction of a manufacturing cost and the use of quality adaptable to different load characteristics on the surface and reverse of an engagement arm portion. SOLUTION: The shift fork 23 which has the engagement arm portion 23b extending over a coupling sleeve 20 with the operation of a shift shaft 25 and engageable with a groove 20a in the coupling sleeve 20 comprises a first wear resistant member 28 and a second wear resistant member 29 separated from each other and fixed to the engagement arm portion 23b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift fork having an engagement arm which can be engaged with a coupling sleeve in a transmission, and in particular, a wear-resistant member is fixed to an engagement portion with the coupling sleeve. Shift fork.

[0002]

2. Description of the Related Art In general, a shift shaft in a manual transmission is provided with a shift fork for changing a gear position, and an engagement formed on the shift fork according to the operation of the shift shaft in response to a shift change operation. The arm moves the coupling sleeve while engaging the groove formed on the outer periphery of the coupling sleeve,
It is configured to obtain a desired gear ratio.

When the engaging arm moves while engaging the coupling sleeve, the engaging portion of the engaging arm with the coupling sleeve exerts a reaction force from the coupling sleeve in a direction opposite to the moving direction. Therefore, there is a possibility that abrasion due to the reaction force may occur. In order to prevent this abrasion, a wear-resistant member made of a wear-resistant metal or resin tip is fixed to the engagement portion of the engagement arm with the coupling sleeve.

As a conventional method of attaching a wear-resistant member to an engagement arm, for example, a method described in Japanese Utility Model Laid-Open No. 57-50729 (hereinafter referred to as Conventional Example 1) and Japanese Utility Model Publication No. 56-38576. (Described below)
This is referred to as Conventional Example 2. ). That is, Conventional Example 1
In the prior art 2, a wear-resistant member (claw member) having a U-shape is fitted and attached to the tip of the engaging arm. It is.

[0005]

However, the conventional examples 1 and 2 have the following problems.
That is, according to Conventional Example 1, a material that cannot be insert-molded (for example, a sintered material) cannot be used as the wear-resistant member, and the range of materials to be selected when manufacturing a shift fork is narrowed. In addition, there is a problem that a mold for insert molding is required, which increases the manufacturing cost.

Further, according to the conventional example 2, the shape (U-shape) of the wear-resistant member often does not match the thickness of the engagement arm portion of the shift fork. There is a possibility that the elastic member may be damaged at the time of fitting. Since high toughness is required for the wear-resistant member in order to avoid such breakage, there is a problem that the range of choices of materials at the time of manufacturing the shift fork is narrowed as in Conventional Example 1.

[0007] Further, in each of Conventional Example 1 and Conventional Example 2,
Since the material of the wear-resistant member is the same on the front and back of the engagement arm, there is also a problem that it is not possible to adapt to different load characteristics applied to the front and back of the engagement arm.

[0008] The present invention has been made in view of such circumstances, and it is possible to widen the selection range of the material of the wear-resistant member, and to fix the wear-resistant member to the engagement arm portion by insert molding. It is another object of the present invention to provide a shift fork that can be manufactured with a reduced wear cost and made of a material of a wear-resistant member adapted to different load characteristics applied to the front and back surfaces of the engagement arm.

[0009]

According to the first aspect of the present invention,
A shift fork having an engagement arm fixed to a shift shaft of a transmission, straddling a coupling sleeve by an operation of the shift shaft, and engageable with a groove formed on an outer periphery of the coupling sleeve, A separate wear-resistant member is fixed to each of the front and back surfaces of the engagement arm portion at the engagement position with the coupling sleeve.

The invention according to claim 2 is characterized in that the wear-resistant member is fixed to the engagement arm by rivet caulking.

According to a third aspect of the present invention, the wear-resistant member has a concave portion formed on the wear-resistant member or the engagement arm portion, and a convex portion formed on the wear-resistant member or the engagement arm portion. The part is fixed by press-fitting.

[0012]

Embodiments of the present invention will be specifically described below with reference to the drawings. The shift fork according to the present embodiment is applied to, for example, a manual transmission 1 as shown in FIG. The manual transmission 1 includes a main shaft 2 and a counter shaft 3, between which shafts a first gear train G1, a reverse gear train GR, and a second gear train G2 to a fifth gear train G5 are arranged in parallel. Is provided.

The first-speed gear train G1 comprises a main first-speed gear 4 fixed to the main shaft 2 and a counter first-speed gear 9 rotatably supported by the counter shaft 3 while always meshing with the main first-speed gear 4. And the second speed gear train G
The second to fifth gear train G5 always meshes with each of the second main gear 5 to the fifth main gear 8 fixedly mounted on the main shaft 2 and each of the second main gear 5 to the main fifth gear 8 so as to provide a counter. It is constituted by a counter second speed gear 10 to a counter fifth speed gear 13 rotatably supported on the shaft 3.

On the other hand, between the first-speed counter gear 9 and the second-speed counter gear 10, the first-second speed gear 9 and the second-speed counter gear 10 capable of selectively coupling the first-speed counter gear 9 and the second-speed counter gear 10 to the counter shaft 3. A mechanism 16 is provided, and between the main third speed gear 6 and the main fourth speed gear 7, the main third speed gear 6 and the main fourth speed gear 7 can be selectively coupled to the main shaft 2. A four-speed synchronization mechanism 18 is provided. Further, the main fifth speed gear 8 and the main shaft 2
A fifth speed synchronizing mechanism 19 capable of connecting the main fifth speed gear 8 to the main shaft 2 is provided between the first and second speed gears.

The reverse gear train GR includes a reverse drive gear 14 fixed to the main shaft 2 and 1-2.
A reverse driven gear 15 engraved on the coupling sleeve 17 of the speed synchronizing mechanism 16 and a reverse idle gear (operable from a position where the reverse drive gear 14 and the reverse driven gear 15 are simultaneously meshed to a position where the meshed state is released) (Not shown).

The above-described 3-4 speed synchronizing mechanism 18 is moved in one of the axial directions of the main shaft 2 to shift the gear train G
It has a coupling sleeve 20 for establishing either 3 or G4. This coupling sleeve 2
As shown in FIG. 2B, a groove 20a is provided over the entire outer periphery of the shift fork 23, and the shift fork 23 is engaged with the groove 20a. The coupling sleeves 17 and 21 have the same configuration as the coupling sleeve 20 described above, and the grooves in which the shift forks 22 and 23 are respectively engaged are formed over the entire outer circumference.

The shift forks 20, 22, 23 are
It is supported by shift shafts 25 to 27 extending in parallel with the main shaft 2 and the counter shaft 3, and is configured to move in conjunction with the operation of the shift shafts 25 to 27. Then, the engagement grooves 25a, 26a, 27a
By operating a shift arm (not shown) that can be selectively engaged with the gears, the selected shift shafts 25 to 27 are slid in the axial direction, and the 1-2 speed synchronization mechanism 16 and the 3-4 speed synchronization mechanism are operated. 1
It is configured to operate either the 8 or 5 speed synchronizing mechanism 19.

Here, the shift fork of the first embodiment according to the present invention will be described below. Since the shift forks 22 to 24 have the same configuration, the shift fork 23 will be described, and the other shift forks 22 or 24 will be described.
The description of is omitted.

The shift fork 23 is formed by press-forming a relatively thin iron plate having a thickness of about 4 mm. As shown in FIG. 1A, a top 23a, an engagement arm 23b,
A first wear-resistant member 28 and a second wear-resistant member 29 are formed on the engagement arm 23b.
It is provided with.

The top 23a has a concave shape so as to follow the outer peripheral shape of the shift shaft 25, and the shift shaft 25 is fixed to the concave shape by welding. Here, the symbol a in the figure indicates the buildup of the welded portion between the shift shaft 25 and the top 23a. The top 23a and the shift shaft 25 may be formed by another conventional fixing method.

The engagement arm portion 23b straddles the coupling sleeve 20 and can engage with a groove 20a formed on the outer periphery of the coupling sleeve 20, and as shown in FIG. A hole 23bc penetrating through 23ba and the back surface 23bb is formed. A rivet 30 is inserted through the hole 23bc.
a and the first wear-resistant member 28 and the second wear-resistant member on the rear surface 23bb are fixed by caulking.

The first wear-resistant member 28 and the second wear-resistant member 29 are formed separately, and the front and rear surfaces 23b of the engagement arm 23b at the engagement position with the coupling sleeve 20 are formed.
a, 23bb. The first wear-resistant member 28 and the second wear-resistant member 29 may be formed of the same material or may be formed of different materials. Incidentally, these wear-resistant members 28, 29
May be made of an aluminum sintered material, a copper-based bearing material, an aluminum casting, or the like, in addition to a resin chip.

The first wear-resistant member 28 and the second wear-resistant member 29 have substantially the same outer dimensions.
It is fixed to the engaging arm 23b so that 8a and 29a are aligned. Further, it is preferable that the aligned tips 28a and 29a protrude from the tip 23bd of the engagement arm 23b by a minute dimension t. With such a configuration,
The interference of the tip 23bd of the engagement arm 23b with the coupling sleeve 20 can be avoided.

The shift fork 23
Are formed along the outer peripheral edge of the shift fork 23 made of a relatively thin metal plate. The flange portion 23c is formed integrally with the shift fork 23 at the time of press forming, and protrudes in the axial direction of the shift shaft 25 as shown in FIG. In this embodiment, from the viewpoint of weight reduction, the shift fork 23 is a thin plate having a flange portion 23c. However, the shift fork 23 has a large thickness and does not require a flange. Can be applied.

According to the shift fork 23 of this embodiment, the wear-resistant member attached to the engagement arm 23b is separately provided on the front and back surfaces 23ba and 23bb (the first wear-resistant member 28 and the second wear-resistant member). Since each of the members 29) is caulked and fixed with the rivets 30, each of the wear-resistant members 28, 29
Does not require a high degree of dimensional accuracy, and a material having poor toughness can be used. Therefore, the range of choice of the material of the wear-resistant member at the time of manufacturing the shift fork is widened, and the manufacturing cost can be reduced without the need of a mold or the like.

Further, since a material which cannot be used in the insert molding (for example, a cast aluminum product or a sintered material) can be selected and used as a wear-resistant member,
The range of choice of the material of the wear-resistant member at the time of manufacturing the shift fork is expanded.

Further, if the first wear-resistant member 28 and the second wear-resistant member 29 are made of different materials, different load characteristics are applied to the front and back surfaces 23ba, 23bb of the engagement arm 23b. Can be adapted to That is, the load characteristics when the engagement arm 23b moves in the p direction or the q direction in FIG. 1B and engages with the coupling sleeve 20 are different between the front and back surfaces of the normal engagement arm 23b. By selecting a material suitable for the different load characteristics,
Of the wear-resistant member 28 or the second wear-resistant member 29.

Although the first embodiment of the present invention has been described above, the shift fork 23 and the shift shaft 25 are directly welded and joined to each other, as shown in FIG. It may be joined via a pipe 31 welded or bonded to 23a. In such a case, the pipe 31 is slidable in the axial direction of the shift shaft 25 using the fixed shift shaft 25 as a guide, and the engagement grooves 25a and 26 shown in FIG.
a, 27a, which is selectively engageable with the shift shafts 25-2.
7 (in this case, all are fixed) by sliding the pipe 31 joined to the shift fork 23
Is moved to operate either the 1-2 speed synchronization mechanism 16, the 3-4 speed synchronization mechanism 18 or the 5-speed synchronization mechanism 19.

Next, another embodiment according to the present invention will be described. As shown in FIG. 4A, the shift fork according to the second embodiment has a hole 23 on the side of the contact surface (surface 23ba) of the first wear-resistant member 28x with the engagement arm 23b.
convex portions 28xa and 28xb having a diameter slightly larger than the diameter of bc
Is formed, and the opening of the hole 23bc on the front surface 23ba side is press-fitted as a concave portion, and the convex portion 28 is formed on the contact surface (back surface 23bb) of the second wear-resistant member 29x with the engaging arm portion 23b.
The projections 29xa and 29xb similar to xa and 28xb are formed, and the abrasion resistant member is fixed to the engagement arm 23b by press-fitting the opening on the back surface 23bb side of the hole 23Bc as a depression.

According to the shift fork having the wear-resistant member, when the wear-resistant member is attached to the engagement arm,
A jig for caulking or the like is not required, and workability can be improved as compared with the first embodiment.

The shift fork according to the third embodiment has a first wear-resistant member 2 as shown in FIG.
The concave portion 28ya, the convex portion 28yb, and the convex portion are provided on the contact surface (front surface 23ba) of the second arm 8y with the engaging arm portion 23b of the second wear-resistant member 29y. A portion 29ya and a concave portion 29yb are formed, and the engagement arm portion 23 is formed.
The abrasion-resistant member is fixed to the engaging arm 23b by press-fitting the convex portion 29ya into the concave portion 28ya via the hole 23bc of FIG.

According to the shift fork having such a wear-resistant member, the coupling force between the first wear-resistant member and the second wear-resistant member can be increased as compared with the second embodiment. .

Further, as shown in FIG. 4C, the shift fork according to the fourth embodiment has a convex portion h and a concave portion i on the front surface 23ba side of the engaging arm portion 23b, and a concave portion j and a concave portion j on the rear surface 23bb side. In addition to the formation of the convex portion k, the concave portion 28za and the concave portion i each having a diameter slightly smaller than the diameter of the convex portion h are provided on the contact surface (front surface 23ba) of the first wear-resistant member 28z with the engagement arm portion 23b.
Is formed on the contact surface (rear surface 23bb) of the second wear-resistant member 29z with the engagement arm 23b, the protrusion having a diameter slightly larger than the diameter of the recess j. A portion 29za and a concave portion 29zb having a diameter slightly smaller than the convex portion k are formed.

Then, the convex portions h and 28zb are replaced with the concave portions 28z.
a and i, and the protrusions 29za and k are press-fitted into the recesses j and 29zb.
A first wear-resistant member 28z is fixed to the front surface 23ba side of b, and a second wear-resistant member 29z is fixed to the back surface 23bb side.

According to the shift fork having the abrasion-resistant member, the workability of attaching the abrasion-resistant member to the engagement arm portion is improved as compared with the first embodiment. In comparison, the bonding force between the first wear-resistant member and the second wear-resistant member can be increased.

The shift fork and the shift shaft in the second to fourth embodiments may be directly welded to each other, or may be connected via the pipe 31 described in the first embodiment. It may be done.

Although the present invention has been described above, the present invention is not limited to this, and other various types of shift forks (for example, those having a lightening hole (hole) or the like for reducing weight) are formed. Or the outer contour has another shape). In addition, various materials having wear resistance can be used as the wear-resistant member.

For fixing the wear-resistant member to the engagement arm portion, other various fixing methods (for example, welding or bonding with an adhesive) can be applied in addition to the above-described rivet caulking or press-fitting method. . Furthermore, in the present embodiment, the present invention is applied to a shift fork of a manual transmission, but may be applied to a shift fork used for switching between 2WD and 4WD in an automatic transmission, for example.

[0039]

According to the first aspect of the present invention, since the separate wear-resistant members are fixed to the front and back surfaces of the engagement arm, respectively, the range of choice of the material of the wear-resistant members can be expanded. The material of the wear-resistant member is reduced in manufacturing cost as compared with fixing the wear-resistant member to the engagement arm by insert molding, and is adapted to different load characteristics applied to the front and back surfaces of the engagement arm. It can be.

According to the second aspect of the present invention, since each of the separate wear-resistant members is fixed to the engagement arm portion by rivet caulking, the range of choice of the material of the wear-resistant member can be expanded. In addition, the wear-resistant member can be fixed to the engagement arm by a general-purpose method, and workability can be improved.

According to the third aspect of the present invention, each of the separate wear-resistant members is fixed to the engagement arm by press-fitting.
The range of choice of the material of the wear-resistant member can be widened, and the wear-resistant member can be fixed to the engagement arm by a general-purpose and simple method, so that the workability can be improved. . Further, since a fixing means such as a rivet is not required, the number of parts can be reduced as compared with the second aspect of the present invention.

[Brief description of the drawings]

FIG. 1A is a front view showing a shift fork according to a first embodiment of the present invention, and FIG. 1B is a sectional view taken along line XX in FIG.

FIG. 2 is a sectional view taken along line YY in FIG.

FIG. 3 is a longitudinal sectional view showing a state in which the shift fork according to the present invention is joined to a shift shaft via a pipe.

FIG. 4 (a) is a cross-sectional view showing a mounted state of a wear-resistant member in a shift fork according to a second embodiment of the present invention, and (b) wear resistance in a shift fork according to a third embodiment of the present invention. Sectional view showing an attached state of the elastic member,
(C) A cross-sectional view showing an attached state of a wear-resistant member in a shift fork according to a fourth embodiment of the present invention.

FIG. 5A is a top view showing a manual transmission to which the shift fork according to the present invention is applied, and FIG.
Top view showing a coupling sleeve in a manual transmission to which a shift fork according to the present invention is applied

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Manual transmission 2 ... Main shaft 3 ... Counter shaft 4 ... Main 1st gear 5 ... Main 2nd gear 6 ... Main 3rd gear 8 ... Main 4th gear 8 ... Main 5th gear 9 ... Counter 1st gear 10 ... Counter 2nd gear 11 ... Counter 3rd gear 12 ... Counter 4th gear 13 ... Counter 5th gear 14 ... Reverse drive gear 15 ... Reverse driven gear 16 ... 1-2 speed synchronizing mechanism 17, 20, 21 ... Coupling sleeve 18 ... 3-4 speed synchronizing mechanism 19 ... 5 speed synchronizing mechanism 20a ... groove 22,23,24 ... shift fork 23a ... top 23b ... engagement arm 23ba ... surface 23bb ... back side 23bc ... hole 23bd ... tip 23c ... flange 25 26, 27: shift shafts 28, 28x, 28y, 28z: first wear-resistant member 29 29x, 28y, 28z ... second wear-resistant members 28a, 29a ... tips 30 ... rivets 31 ... pipes G1 to G5 ... 1st gear train to 5th gear train GR ... reverse gear trains 28xa, 28xb, 29xa, 29xb ... Convex (second
Embodiment) 28yb, 29ya ... convex part (third embodiment) 28ya, 28yb ... concave part (third embodiment) h, k, 28zb, 29za ... convex part (fourth embodiment) i, j, 28za, 29zb ... Recess (fourth embodiment)

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kazufumi Hosoda 7111 Ubumi, Yuto-cho, Hamana-gun, Shizuoka Pref.

Claims (3)

[Claims] A shift arm which is fixed to a shift shaft of a transmission, and which has an engagement arm portion which straddles a coupling sleeve by an operation of the shift shaft and is engageable with a groove formed on an outer periphery of the coupling sleeve. A shift fork, wherein a separate wear-resistant member is fixed to the front and back surfaces of the engagement arm portion at the engagement position with the coupling sleeve. 2. The device according to claim 1, wherein the wear-resistant member is fixed to the engaging arm by rivet caulking.
The described shift fork. 3. The wear-resistant member is formed by press-fitting a protrusion formed on the wear-resistant member or the engagement arm into a recess formed on the wear-resistant member or the engagement arm. The shift fork according to claim 1, wherein the shift fork is fixed.