JP2846796B2 - Work machine 2WD / 4WD switching structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-wheel drive / four-wheel drive switching structure of a working machine such as a lawn mower or a rice transplanter, and more particularly, to a rationalizing structure by fusing the switching means with a rolling support means.

[0002]

2. Description of the Related Art In a working machine capable of four-wheel drive, it is common to support one of the front and rear wheels in a freely rolling manner in order to obtain an effective driving force by reliable four-wheel grounding. For example, the lawn mower disclosed in Japanese Utility Model Laid-Open Publication No. 4-71305 is advantageous in that it is difficult to damage the turf due to the reliable dispersion of the ground load into four wheels.

[0003]

A four-wheel drive machine has a switching clutch for two-wheel drive.
As in the tractor shown in 3-291723,
The switching clutch is disposed on the transmission case side to consolidate functions. However, basically, it is desirable to set it for two-wheel drive and to provide a four-wheel drive machine with an additional switching clutch outside the transmission in order to cope with the downsizing of the transmission and to make it more versatile. . An object of the present invention is to provide a rational structure in which the two-wheel drive and four-wheel drive switching clutches are used as a transmission exterior as well as rolling support means for the wheels to be switched and are organically combined. It is in the point to let.

[0004]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a four-wheel drive capable of transmitting and connecting a transmission for transmitting the power of a drive source to one of front and rear drive wheels and a differential mechanism for the other wheel. A four-wheel drive shaft is provided with a switching clutch that has a driving shaft and intermits power to the differential mechanism, and a support case in which the switching clutch is housed to support the other wheel in a freely rolling manner. The rear axle case in which is accommodated is configured to be a member that swingably supports around a longitudinal axis.

[0005]

In other words, by providing the two-wheel drive / four-wheel drive switching clutch at the four-wheel drive shaft portion, the transmission can be used in a two-wheel drive machine in a state in which unnecessary switching clutches are omitted and there is no waste. In a four-wheel drive machine, by providing a four-wheel drive shaft, a necessary switching clutch can be provided. In the four-wheel drive machine, the support case containing the necessary switching clutch is a member for rollingly supporting the wheels to be switched, so that a dedicated support member can be omitted.

[0006]

Therefore, only the four-wheel drive machine needs the
A switching clutch is provided at the wheel drive shaft, and the clutch case is a rolling support member. A transmission that can be used for general purposes was provided.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings for a case of a lawn mower as an example of a working machine. FIG. 1 shows a front-mounted riding lawn mower, and FIG. 2 shows a main part of its transmission system.
Is a front drive wheel, 4 is a rear steering wheel, and 5 is a mower. The power of the engine 2a is transmitted to the HST 7 via the transmission shaft 6,
The output shaft 7a and the first differential mechanism 8 for the front wheels are gear-linked via a transmission Tm of the transmission case M, and are transmitted to a four-wheel drive shaft 9a to be described later. Further, the output shaft 7c, which is an extension of the input shaft 7b of the HST 7, and the mower 5 are linked by a transmission shaft 10.

A rear steering wheel 4 is provided at the rear of the four-wheel drive shaft 9a.
, And a supporting mechanism 27 that supports the rear wheel 4 in a freely rolling manner. As shown in FIGS. 2 and 3, the rear wheel drive device 9 includes a four-wheel drive shaft 9a and a second wheel differential mechanism 12 for a rear wheel, which are formed by integrating a cover case 11a and a support case 11b. And a switching clutch A for intermittently connecting with a pinion shaft 13 interlocked with a bevel. A drive-side shifter 15 is attached to the intermediate shaft 14 interlocked with the four-wheel drive shaft 9a.
The switching clutch A is formed by fitting a shift fork 16 and a fork shaft 17 for slidingly driving the drive-side shifter 15 to the cover case 11a. That is, the drive shifter 15 is shifted rearward,
Driven shifter 18 externally fitted with spline to pinion shaft 13
When the vehicle is shifted to the front side and the bite with the driven shifter 18 is released, a two-wheel drive state is established.

The support mechanism 27 has a structure in which a front projection 19a of a rear axle case 19 surrounding the second differential mechanism 12 is fitted in the support case 11b, and a rear projection 19b is fitted in the bearing 20. Thus, the rear axle case 19 is supported so as to freely roll around the axis P in the front-rear direction. The casing 11 and the bearing portion 20 are fixedly supported by the body, and the support case 11b is a member having a function of covering the rear wheel drive device 9 and a function of supporting the rear axle case 19.

FIG. 4 shows a support structure for the rear wheel 4.
A steering case 21 for supporting the rear wheel 4 and a rear axle case 19
This is a structure in which the bearing case 22 mounted on the end is pivotally connected so that it can be transmitted by the oblique transmission shaft 23 and can be steered around the axis of the transmission shaft 23. At the lower end of the steering case 21, a seal cap 2 for a bearing 24 for a transmission shaft 23 is provided.
The steering wheel 21 is provided at a position slightly above the lower end of the steering case 21 for the purpose of reducing the possibility of contact with an obstacle. Reference numeral 26 denotes a groove formed at the lower end of the steering case 21 for removing the seal cap 25 (see FIG. 5).

[Alternative Embodiment] The rear wheel is always a driving wheel, and
The front wheels may be configured as steered wheels, and a two-wheel drive / four-wheel drive switching structure for the front wheels may be configured.

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration shown in the accompanying drawings.

[Brief description of the drawings]

FIG. 1 is a side view of a lawn mower.

FIG. 2 is a partially cutaway side view showing a transmission system.

FIG. 3 is a sectional view showing the structure of a switching clutch.

FIG. 4 is a sectional view of a main part showing a support structure of a rear wheel.

FIG. 5 is a bottom view of the lower end of the steering case.

[Explanation of symbols]

 Reference Signs List 3 drive wheel 4 wheel 9a 4-wheel drive shaft 11b support case 12 differential mechanism 19 rear axle case A switching clutch Tm transmission

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-227028 (JP, U) (58) Fields surveyed (Int. Cl. ⁶ , DB name) B60K 17/32 B60K 17/344

Claims (1)

(57) [Claims] A transmission (Tm) for transmitting the power of a drive source to one of front and rear drive wheels (3).
And a differential mechanism (1) for the other wheels (4) and (4).
2) is provided with a four-wheel drive shaft (9a) capable of transmission connection with
A switching clutch (A) for interrupting power to the differential mechanism (12) is provided at the four-wheel drive shaft (9a), and the other wheels (4) and (4) are supported in a freely rolling manner. The support case (11b) accommodating the switching clutch (A) is a member for supporting the rear axle case (19) accommodating the differential mechanism (12) so as to be swingable around a longitudinal axis. 2WD and 4 working machines
Drive switching structure.