JP2886055B2 - 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 a two-wheel drive / four-wheel switching clutch is used as a transmission exterior and a rolling support means for a drive switching target wheel is combined, and these are organically combined. Is to do.

[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 portion is provided with a switching clutch that has a driving shaft and intermits power to the differential mechanism, and a clutch case accommodating the switching clutch so as to support the other wheel in a freely rolling manner. The rear axle case in which the rear axle case is accommodated is configured as a member that is swingably supported around the longitudinal axis, and the clutch case is fixed to the body while the rear axle case is supported. An intermediate shaft for interlocking the input shaft of the differential mechanism and the four-wheel drive shaft, and a sliding shaft in the axial direction in a torque transmitting state to the intermediate shaft. Characterized in that the shift fork for shifting the driving side shifter to be fitted, are then supported in the cover case.

[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 clutch case that houses the necessary switching clutch is a member that rolls and supports the drive switching target wheel, so that a dedicated support member can be omitted.

[0006] The clutch case is divided into a cover case and a support case. A support case for supporting the rear axle case is fixed to the body, and an intermediate shaft and a shift fork for fitting a shifter to the cover case are provided. Therefore, the components of the switching clutch can be pre-assembled in the cover case and then assembled to the support case. It can be easily attached and disassembled.

[0007]

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 generalized and facilitates assembling and disassembling of the switching clutch and maintenance and inspection thereof have been provided.

[0008]

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.

At the rear of the four-wheel drive shaft 9a, the steering rear wheel 4 is provided.
, 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 rear wheel drive shaft 9a, which are formed by integrating a cover case 11a and a support case 11b.
A switching clutch A for connecting / disconnecting a pinion shaft 13 interlocked with a bevel to the differential mechanism 12 is provided.

The switching clutch A includes a shift fork 16 and a fork shaft 17 which spline the drive side shifter 15 to the intermediate shaft 14 interlockingly connected to the four-wheel drive shaft 9a and operate the drive side shifter 15 to slide. Cover case 11a
It is configured to support. That is, the drive-side shifter 15
Is shifted to the rear and engaged with the driven shifter 18 splined to the pinion shaft 13 to form a four-wheel drive state, and shifted forward to release the two-wheel drive state when the bite with the driven shifter 18 is released. become.

As shown in FIGS. 4 and 5, fork shaft 17
Are supported by penetrating the cover case 11a laterally, and two seal rings 21 and 21 and two snap rings 2 are provided.
Shift fork 1
6 is fitted in a detented state by a two-sided cut oval cross section. A lever 23 is attached to the outer part of the case of the fork shaft 17, and the lever 23 is provided with a return spring 24.
, The clutch pedal 25 is urged in the clutch disengagement direction, and the clutch pedal 25 is interlocked and linked by a connecting member 26 such as a wire or a rod. Therefore, the intermediate shaft 14 fitted with the drive-side shifter 15, the lever 23 and the shift fork 16
The cover case 11a in a state where the fork shaft 17 provided with
It can be assembled and removed from b, easy to assemble and disassemble, and convenient for maintenance and inspection.

The support mechanism 27 includes a rear projection 19a of the rear axle case 19 surrounding the second differential mechanism 12 and the support case 11b, and a rear projection 19b and 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. Note that the clutch case 11 and the bearing portion 20 are fixedly supported on the body, and the support case 11b is a member having a cover function of the rear wheel drive device 9 and a support function of the rear axle case 19.

As shown in FIGS. 6 and 7, the intermediate shafts 14 and 4
The wheel drive shaft 9a is interlocked and connected by a spline-fitted coupling 28, and the coupling 28 is positioned by a roll pin 29 that penetrates a gap between the shafts 14 and 9a. The inside of the coupling 28 is filled with grease with left and right seal rings 30 and 30 to prevent oxidative wear of the spline portion, but a rubber rod 31 is press-fitted or sealed into the roll pi 29 to prevent grease from leaking from the roll pin 29. Has been entered.

[Alternative Embodiment] The rear wheels are always driven wheels, 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 showing a support structure of the shift fork.

FIG. 5 is an enlarged sectional view showing a main part of the switching clutch.

FIG. 6 is a sectional view of a coupling part.

FIG. 7 is a sectional view of a roll pin.

[Explanation of symbols]

 Reference Signs List 3 drive wheel 4 wheel 9a 4 wheel drive shaft 11 clutch case 11a cover case 11b support case 12 differential mechanism 13 input shaft 14 intermediate shaft 15 drive side shifter 16 shift fork 19 rear axle case A switching clutch Tm transmission

──────────────────────────────────────────────────の Continued on the front page (72) Inventor Yoshikazu Togoshi 64, Ishizukita-cho, Sakai-shi, Osaka Inside the Kubota Sakai Works, Ltd. Office (72) Inventor Akiyoshi Takemoto 64 Ishizukita-cho, Sakai City, Osaka Prefecture Inside Kubota Sakai Factory (72) Inventor Kenichi Nakajo 64 Ishizukita-machi Sakai City, Osaka Prefecture Inside Kubota Sakai Factory (56) References JP-A-3-529 (JP, A) JP-A 63-176727 (JP, U) JP-A 4-71305 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) B60K 23/08 F16H 57/02

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).
And a switching clutch (A) for intermittently connecting and disconnecting power to the differential mechanism (12) is provided at the portion of the four-wheel drive shaft (9a). In order to support the other wheels (4) and (4) in a freely rolling manner, a clutch case (11) accommodating the switching clutch (A) is replaced with a rear axle case accommodating the differential mechanism (12). (19) is constituted as a member which is supported so as to be swingable around the longitudinal axis, and the clutch case (11) is connected to the rear axle case (1).
A support case (11b) fixed to the machine body while supporting 9) and a cover case (11a) serving as a lid of the support case (11b), and an input shaft (11) of the differential mechanism (12). 13) and an intermediate shaft (14) for interlocking the four-wheel drive shaft (9a), and a drive-side shifter (14) fitted to the intermediate shaft (14) slidably in the axial direction in a torque transmitting state. 15) and a shift fork (16) for shifting the cover case (11).
The 2WD / 4WD switching structure of the working machine supported in a).