JPH07125557A - Shift operating structure of transmission gear - Google Patents

Abstract

PURPOSE:To reduce the number of part items as leaving a function kept up intact by taking a new look at a differential-lock shift operating structure. CONSTITUTION:A shift fork 13 is installed in a fulcrum shaft 12 supported by a differential case 4 and an axle case 5 free of slide motion and relative rotation in a state that an axial movement is regulated, and such a run-over cam mechanism A as making this shift fork 13 reciprocatively shiftable in the axial direction by means of a turning operation of the fulcrum shaft 12, is provided, while this run-over cam mechanism A is composed of an engagement between a cam part 17 formed in the shift fork 13 and a pin 16 pierced through and clamped to the fulcrum shaft 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift operation structure of a transmission device such as a diff lock device and a transmission.

[0002]

2. Description of the Related Art For example, the operation structure of a diff lock device disclosed in Japanese Utility Model Laid-Open No. 55-63218 discloses a shifter which is loosely fitted on a support shaft and a pressing member which is fitted on the support shaft so as to rotate integrally. It has been common to construct a riding cam mechanism with a member, and perform a reciprocal shift operation of a shifter by rotating an operation arm attached to an outer portion of a case of a support shaft.

[0003]

In the above structure, in addition to the shift fork, a cam member, a return spring, a double nut for preventing the spindle from coming off, and the like for forming a riding cam mechanism in pairs with the shift fork. Many parts are required, and the number of parts is large for the function of converting rotational movement into shift movement, and there seems to be room for improvement. The purpose of the present invention is to
The shift operation structure is reviewed to reduce the number of parts while maintaining the same function.

[0004]

In order to achieve the above object, the present invention fits a shift fork slidably and relatively rotatably on a support shaft supported by a transmission case in a state where axial movement is restricted. And a lift cam mechanism capable of reciprocally shifting the shift fork in the axial direction by rotating the support shaft. The lift cam mechanism is provided with a cam portion formed on the shift fork and a support shaft. It is characterized by arranging a pin which is fixedly penetrated through the pin in such a manner that both of them engage with each other.

[0005]

The riding cam mechanism is composed of the engagement of the rotating cam and the fixed cam that does not move in the axial direction. Conventionally, the shift fork corresponds to the fixed cam and the pressing member corresponds to the rotating cam. Therefore, in the above characteristic configuration, the pin has a function of a fixed cam. In other words, the pin rotates to move the cam portion of the shift fork in the axial direction, whereby the fixed cam in the conventional structure can be omitted.

[0006]

As a result, as a result, the riding cam mechanism 2
By devising that the fixed cam of the individual cam members is composed of pins, the fixed cam can be omitted, the number of parts can be reduced, and a shift operation structure capable of cost reduction can be provided.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings when applied to a diff lock device for a tractor. FIG. 1 shows the lower side of the transmission from the differential mechanism for the drive wheels of the tractor. 1 is a differential mechanism, 2 is a side brake, 3 is an axle, 4 is a differential case, 5 is an axle case, and 7 is a differential lock device.

The diff lock device 7 includes a spline portion 11a of a diff output shaft 11 to which a diff output gear 8 on one side is fitted.
A meshing portion 9a of the differential frame 9, a shifter 10 externally fitted to the spline portion 11a, a support shaft 12 extending over the differential case 4 and the axle case 5, a shift fork 13 loosely fitted to the support shaft 12, It is composed of a return spring 14 and the like.
The shift fork 13 is slidably and relatively rotatably fitted on the support shaft 12, and the operation arm 15 outside the case is used to rotate the support shaft 12 so that the shift fork 13 can be reciprocally shifted in the axial direction. The riding cam mechanism A is provided.

That is, as shown in FIGS. 1 to 3, a concave cam portion 17 provided on the shift fork 13 and the support shaft 1 are provided.
The ride-on cam mechanism A is configured by arranging the pin 16 fixed to penetrate through 2 in a state of engaging with each other, and the pin 16 rotates in accordance with the rotation of the support shaft 12 to force the cam portion 17. It is possible to perform a return slide operation by the pressing slide and the return spring 14. That is, the operation arm 15 outside the axle case 5
When is not operated, the shift fork 13 is pressed to the right by the urging force of the return spring 14 as shown in FIG. 1, and the pin 16 is located at the valley portion 17a of the cam portion 17 and the shifter 10 and the meshing portion 9a. Is maintained in a non-occluded diff actuated state. Then, when the operation arm 15 is rotated, the pin 16 pushes the inclined surface portion of the cam portion 17 to rotate the operation mechanism 15, and the operation mechanism 15 moves up, and the shift fork 13 moves to the left. Then shifter 1
0 is engaged with the meshing portion 9a, and the differential lock state appears.

The differential case 4 and the axle case 5 are line w
The structure is divided into left and right, and by inserting and fixing the pin 16 into the support shaft 12 in advance and then supporting the support shaft 12 in the case, it is possible to avoid the troublesome pin mounting operation in the inner part of the case in the related art. You can

It should be noted that reference numerals are given in the claims for convenience of comparison with the drawings, but the present invention is not limited to the configuration of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a developed sectional view showing the structures of a differential mechanism and a differential lock device.

FIG. 2 is a sectional view of the diff lock device showing a diff lock state.

FIG. 3 is a cross-sectional view of a main part showing a structure of a riding cam mechanism.

[Explanation of reference numerals] 5 transmission case 12 spindle 13 shift fork 16 pin 17 cam portion A climbing cam mechanism

Claims (1)

[Claims] 1. A shift fork (13) is slidably and relatively rotatably fitted on a support shaft (12) supported by a transmission case (5) in a state in which axial movement is restricted, and the support shaft is provided. The shift fork (1
3) is equipped with a hoisting cam mechanism (A) capable of axially reciprocating shift movement, and this hoisting cam mechanism (A) is used as a cam portion (17) formed on the shift fork (13). , A shift operation structure of a transmission, which is configured by arranging a pin (16) penetratingly fixed to the support shaft (12) in a state in which the two (17) and (16) are engaged with each other.