JPH0587406B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wheel drive structure for a walk-behind working machine, such as a walk-behind lawn mower, which has a relatively small running load.

[Conventional technology]

In the case of the above-mentioned walk-behind work machine, in order to improve workability, it is preferable to change the running speed steplessly.
As disclosed in Japanese Patent No. 62-17827, a disc-type continuously variable transmission was developed.

[Problem that the invention seeks to solve]

However, in the conventional structure described above, although the walk-behind work machine is a relatively small machine, the disk type continuously variable transmission has a large external shape due to its structure, resulting in an increase in the size of the machine as a whole. There were drawbacks that led to this. Furthermore, since the transmission device itself does not have a power intermittent function, a dedicated clutch mechanism for power intermittent operation must be separately provided, and two running levers are required, one for shifting operation and one for clutch operation. The structure is complicated, and the operability is poor.
There was room for improvement.

The present invention aims at making the body more compact and simplifying the structure.

[Means for solving problems]

The characteristic configuration of the present invention is as follows: A bevel gear attached to an input shaft receiving power from an engine and a bevel gear loosely fitted to a transmission shaft for driving wheels are engaged, and the loosely fitted bevel gear and the transmission shaft are connected to both bevel gears. and a shift member for adjusting the pressing force of the friction transmission mechanism is configured to be operable by a hand lever. The functions and effects are as follows.

[Operation] (a) With the above characteristic configuration, by arranging the friction transmission mechanism in the corner area inevitably formed by each of the bevel gears, the space can be used effectively and the external size can be increased. A power transmission system can be constructed without any problems.

(b) Moreover, with the above characteristic configuration, by changing the pressing force of the shift member by operating the hand lever, the transmission friction force of the friction transmission mechanism is changed, and the rotational speed of the transmission shaft is infinitely changed. The friction transmission mechanism can be set to the power cut-off state by performing a speed change operation by changing the pressure to , and then releasing the pressing force. In other words, it is possible to perform gear changes and clutch on/off operations using a single lever.

〔Effect of the invention〕

Therefore, the above-mentioned effects (a) and (b) make it possible to make the fuselage more compact, and also eliminate the need for a dedicated clutch mechanism, simplifying the structure and, in turn, making it possible to reduce costs.

〔Example〕

FIG. 4 shows a traveling lawn mower that is an example of a traveling working machine according to the present invention. This lawnmower has a pair of left and right front wheels 1, 1, a pair of left and right rear wheels 2,
An engine 5 is attached to the upper part of a cutting blade housing 4 which includes a cutting blade 3 which is rotatable around a vertical axis, and the output of this engine is transmitted to the cutting blade 3 via a cutting blade clutch 6. In addition, the engine 5
Power is transmitted to the rear wheels 2, 2 via a longitudinal power transmission shaft 8 and a continuously variable transmission section A, which are interlocked and connected to a PTO shaft 7 protruding from the rear side. A handle 9 and a grass collection container 10 are attached.

As shown in FIGS. 2 and 3, the proximal end of the operating handle 9 is fixed to the handle mounting member 11 with a knob fastener 12, and the lower end of the handle mounting member 11 is fixed to the cutting blade housing 4. The operating handle 9 is pivotally connected to the handle member 13 via a pivot member 13, so that the operating handle 9 can be vertically swung and adjusted integrally with the handle attachment member 11. A through hole 14 is formed inside the pivot member 13, and a rotary shaft 15 is freely rotatably housed in the through hole 14. Rotating blade 1 that rotates due to the blowing force accompanying rotation
6 is attached, and a rotation display member 18 having a spiral band-shaped mark 17 formed on the outer end is provided. That is, when the grass collection container 10 is filled with grass clippings, the rotation of the rotary blade 16 is prevented, and this can be easily determined during operation by visually observing the rotation display member 18. be.

Next, with reference to FIG. 1, the structure of the continuously variable transmission section A will be described in detail.

A bevel gear 21 is attached to the rear end of the power transmission shaft 8, and the bevel gear 21 and the bevel gear 23 loosely fitted to the relay shaft 22 for driving the axle are engaged with each other. are interlocked and connected via a friction transmission mechanism 24. The friction transmission mechanism 24 is arranged in a compact manner by effectively utilizing the corner area B formed by the bevel gears 21 and 23, and the shift member 25 connects a large number of drive side friction plates 27 and driven side friction. It is configured so that frictional transmission occurs by pressing the plate 28. That is, a transmission drum 26 is provided extending to the area B side of the bevel gear 23, and a large number of drive-side friction plates 27 are engaged with the inner peripheral side of the transmission drum 26 so as to be non-rotatable and movable in the axial direction. In addition to supporting the drive side friction plate 27
The driven side friction plates 28 sandwiched between the driven sleeve 29 and the driven sleeve 29 are fitted around the transmission shaft 22 by splines. The driven sleeve 29 is configured to rotate together with the transmission shaft 22 through engagement with a pin 38 provided through the transmission shaft 22, and the driven sleeve 29
The rotational power transmitted to the gear 9 is transmitted to the gear 30 attached to the transmission shaft 22 and the axle gear 3 that meshes with this gear 30.
1 to the axle 32, and the rear wheels 2, 2
It is configured to drive.

As shown in the same figure and FIG. 4, the operating wire 36 and They are linked together via a spring 40, and the shift fork 34 is biased in the direction of releasing the friction plate pressure by a helical spring (not shown) provided on its support shaft 39.

Therefore, in a free state in which the hand lever 35 is not operated, the pressing force of the shift member 25 against the friction transmission mechanism A is released, resulting in a power cutoff state. As the hand lever 35 is pressed and swung forward around the fulcrum X, the amount of deflection of the spring 40, that is, the pressing force of the friction transmission mechanism A increases in accordance with the amount of swiveling displacement, and the rear wheels 2, The structure is such that the transmission speed to No. 2 can be increased steplessly.

[Another example]

Instead of the relay shaft 22, the axle 32 may be directly interlocked and connected to the friction transmission mechanism 24.

Incidentally, although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structure shown in the accompanying drawings.

[Brief explanation of the drawing]

The drawings show an embodiment of the axle drive structure for a walk-behind work machine according to the present invention, and FIG. 1 is a longitudinal sectional front view of the main part;
Fig. 2 is a partially cutaway plan view of the control handle attachment part, Fig. 3 is a plan view of the body of the traveling lawn mower, and Fig. 4
The figure is an overall side view of the traveling lawn mower. 5... Engine, 8... Input shaft, 21... Bevel gear, 22... Transmission shaft, 23... Bevel gear,
24...Friction transmission mechanism, 25...Shift member, 3
5... Hand lever, B... Corner area.

Claims (1)

[Claims] 1 A bevel gear 21 attached to an input shaft 8 that receives power from the engine 5, and a transmission shaft 2 for driving wheels.
A bevel gear 23 loosely fitted into the bevel gear 2 is engaged with the bevel gear 23, and the loosely fitted bevel gear 23 and the transmission shaft 22 are connected through a multi-plate friction transmission mechanism 24 arranged in a corner area B formed by both bevel gears 21 and 23. A wheel drive structure for a walking type working machine, in which the shift member 25 for adjusting the pressing force of the friction transmission mechanism 24 is configured to be operable by a hand lever 35 by interlocking and connecting the shift member 25 for adjusting the pressing force of the friction transmission mechanism 24.