JPS5897718A - Surface treating method of shift fork pawl part - Google Patents

Abstract

PURPOSE:To increase the wear resistance and the durability, by providing the unevenness on the surface of a shift fork which performs a switching operation with a touch to a switching member such as a change gear, a clutch hub sleeve, etc. and then laminating the fluoroplastic on the uneven surface of the shift fork. CONSTITUTION:Number of grooves having the sections of V-shpe 3 or U-shape 4 are formed by a pressing or cutting process on the surface where a pawl part 2 of a shift fork touches a switching member. The fluoroplastic 5 is laminated on the surface of the groove by a spraying, dipping, coating process, etc. A smooth and shallow unevenness 8 is formed on the surface of the groove to hold the lubricating oil 9. Thus the lubricating properties can be improved. As a result, both the wear resistance and the durability can be increased for the pawl part 2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a surface treatment method applied to the pawls of shift forks used in switching operation parts of automobile transmissions, clutches, and the like.

The shift fork 7 has a trap as shown in FIGS. 1 and 2, and a guide shaft (not shown) is attached to the base of the shift fork 1.
is fixed, and by moving this guide shaft in the axial direction, the clutch hub sleeve of the change gear or clutch (none of which is shown) into which the pawls 2, 2 formed at the tip of the shift fork l fit. is moved in the axial direction to change gears or engage/disengage the clutch.

As described above, both side surfaces and the inner circumferential surface of the pawls 2, 2 of the shift 7 oak 1 slide into grooves of the change gear or clutch hub sleeve with a large surface pressure, so that wear resistance becomes a problem.

In the conventional shift fork 1, the pawl portion 2 of this
, 2 is rounded to strengthen the wear resistance, and after the claws 2, 2 are subjected to prescribed heat treatment such as hardening, ultra-hard chrome plating,
Alternatively, molybdenum spraying or the like is applied to improve the wear resistance of this part.

However, although the wear resistance of the pawl of the shift fork 1 has been improved as described above, the sliding contact of the groove of the change gear or clutch hub sleeve of the other side with which this pawl comes into sliding contact is poor! [
A problem arose in that the parts were damaged due to wear. t
Abnormal noise is observed due to wear of the sliding contact surface of the octopus.

A solution to this problem is to laminate a resin with a small friction coefficient and good wear resistance on the pawl portion 2 of the shift fork 1, but when processing the flat cutting surface of the pawl portion 2, the resin layer is There was a point at which it became difficult to achieve flatness if the layers were thicker, and if they were laminated thinner, they would easily peel off.

The present invention was conceived in view of the above, and has a shift fork pawl that has a small friction coefficient, excellent heat resistance, and wear resistance, and allows for example fluororesin to be thinly laminated without peeling. This paper aims to provide a surface treatment method.

The embodiments will be described below with reference to the drawings.

Both sides and inner diameter surface of the claw portion 2.2 of the shift fork 1,
That is, grooves 3 and 4 having a cross-sectional shape of 7 (Fig. 3) and a U-shape (Fig. 4) are formed on the sliding surfaces that fit into and slide into the grooves of the change gear and clutch hep sleeve. A large number of sheets are formed by pressing or cutting, and the fluororesin 5 is laminated on the processed surface by means such as spraying, dipping, coating, or the like.

The direction of the grooves 3 and 4 can be perpendicular to the sliding direction as shown in Figure 5(a) K, or inclined in the sliding direction as shown in Figure 5(b) K, or tilted in the sliding direction as shown in Figure 5(c). As shown in Fig. 5(d), it may be placed in the direction of inclination.
It may also be shaped like an arc as shown in .

In addition, as shown in FIGS. 6(1) and 6(b), several 6° recesses may be provided on each surface to which the fluorine resin is transferred.

As shown in Figs. 3 and 4, do not intentionally create smooth unevenness 8 on the surface of the fluororesin layered on the uneven surface of the shift fork I, and apply lubricant 9 to this area.
can be accumulated to improve lubrication performance.

The present invention is as described above, and a switching member such as a change gear or a clutch hep sleeve is operated to switch. In the pawl portion of the shift fork, we provide unevenness on the sliding surface of the shift fork pawl portion with respect to the switching member, and then apply a synthetic material such as fluororesin, which has a low friction coefficient and excellent heat resistance and wear resistance, on this uneven surface. Since the resin is laminated, the synthetic resin can be thinly laminated without peeling.

[Brief explanation of drawings]

Figure 1 is a front view of the shift fork, Figure 2 is Figure 1.
-1MK cross-sectional view, Figures 3 and 4 are A-A in Figure 1
The enlarged cross-sectional view taken along IIK, and each of FIGS. 5 and 6 are front views showing examples of uneven shapes. 1 is shift 7 oak, 2 is the claw part, 3.4 is the groove, 5 is fluororesin. Applicant Kubota Iron Works Co., Ltd. Representative Patent Attorney Masaaki Yonehara Patent Attorney Tadashi Hamamoto (a) (bl (c)
+d+Figure 6(a) (bl

Claims (1)

[Claims] In the claw part of the shift 5 fork that switches the switching member such as the change gear or clutch hub sleeve,
The sliding surface of the shift fork claw with respect to the switching member is provided with unevenness, and then a synthetic resin such as a fluororesin having a small coefficient of friction and excellent heat resistance and wear resistance is laminated on the unevenness. How to treat both sides of the Shift 7 oak claw.