JPH0759430A - Riding lawn mower - Google Patents

Abstract

(57) [Summary] [Purpose] While avoiding damage to the diff-lock mechanism, the diff-lock mechanism is effective on slopes to enable work traveling. [Structure] HST shift operation tool 17 and differential lock operation tool 1
6, the HST speed change operation tool 17 allows the differential lock operation tool 16 to move to the diff lock on position only in the neutral position N, and the HST speed change operation tool 17 operates the diff lock operation in a high speed range outside the low speed range. A check piece 16C for preventing the tool 16 from moving to the diff lock position is provided, and the HST speed change operation tool 17 is moved to a high speed range in a state where the diff lock operation tool 16 is set to the diff lock on position by the operation of the check mechanism. Coil spring 2 that allows
3 is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention requires, for example, cutting work even on a sloping ground, and in order to maintain the stability of the vehicle body during the running, or to run on a level ground without damaging the grass. For this reason, the present invention relates to a riding lawn mower that may travel with a differential lock.

[0002]

2. Description of the Related Art There has been no riding lawn mower of this type in which a gear shift operation tool and a diff lock operation tool are linked with each other.

[0003]

Therefore, when the diff lock is operated in the on state during high-speed traveling, the engaging claws of the diff lock mesh with each other in a shocking manner, so that the shock at that time is large and the diff lock is damaged. Sometimes you can Therefore, when operating the diff lock operation tool, the shift operation tool was once operated to the neutral position, and the diff lock operation tool was operated at the neutral position, but the operation became complicated and unconscious. It was not possible to completely avoid operating the diff lock operating device at high speed. An object of the present invention is to improve the operability by adding a new mechanism that operates the diff lock in an appropriate state across the speed change operation tool and the diff lock operation tool, and to improve the operability of the diff lock during high speed running. The point is to provide something that can prevent the switch to the state.

[0004]

A characteristic configuration according to the present invention is that a gear shift operation tool and a diff lock operation tool are provided only when the gear change operation tool is in a neutral position or in a low speed range of a constant width from the neutral position.
A check mechanism is provided that allows the diff lock operating tool to move to the diff lock engaged position and prevents the shift operating tool from moving to the diff lock position in the high speed range outside the low speed range. When the diff lock operation tool is set to the diff lock on position by the operation of, the elastic interchange mechanism that allows the shift operation tool to move to the high speed range is provided.

[0005]

That is, when the gear shift operating device is operated in the neutral position or in the low speed range of a certain width from the neutral position, the diff lock operating device is moved to the diff lock on position. On the other hand, when the gear shift operating device is operated in the high speed region outside the low speed region, the diff lock operating device is restricted by the restraint mechanism and does not move to the diff lock entering position. Moreover, even when the diff lock operating tool is in the diff lock entering position, when the shift operating tool is operated, the elastic operating mechanism allows the shift operating tool to be operated to the shift position.

[0006]

Therefore, it is possible to regulate the operation to the diff lock-engaged position in the high-speed traveling state without consciously setting the gear shift operation device to the neutral position or the like, and the operability can be improved and the diff lock-engaged state can be improved accordingly. Since the gear shift operation can be performed also in, the work traveling can be performed mainly on the slope without any trouble.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 8, a riding mower equipped with a driving unit 1 in the front and a drive unit 2 from the middle to the rear and a driving unit 3 in the rear, and a front mower F in front of the machine. Are configured.

An engine 4, a radiator 5 and an oil cooler 6 are arranged behind the engine 4 in the drive unit 3. This oil cooler 6 is for cooling the hydraulic oil so that the temperature of the hydraulic oil does not rise and the function of the hydraulic oil is impaired in the summer, but this winter lawn mower is used for snow plows and road cleaning. When used as a vehicle, if the oil cooler 6 is passed through, it will be over-cooled, and the internal pressure of the pipe will rise, the pipe will be damaged, and the oil cooler 6 will be damaged. Therefore, to avoid such a situation, use the following. As shown in FIG. 6, a bypass pipe 7 is provided on the upper surface of the oil cooler 6, and a pump port 6A for taking in oil from the pump and a tank port 6B for returning to the tank are provided on both sides of the bypass pipe 7.
In the summer, as shown in FIG. 6 (a),
The hydraulic pipes 8 and 8 are connected to the pump port 6A and the tank port 6B.
In addition to cooling the hydraulic oil by connecting to and, in the winter, as shown in FIG. 6B, the hydraulic pipes 8 and 8 are disconnected from the pump port 6A and the tank port 6B, and both sides of the bypass pipe 7 are connected. Connect this end to this bypass pipe 7
The oil cooler 6 can be detoured through. The bypass pipe 7 that is not used in the summer is covered with the caps 9 and 9, and the caps 9 and 9 are covered with the pump port 6A and the tank port 6B in the winter so that the caps 9 and 9 can be used in combination. It is trying to make it.

The structure of the traveling drive unit 2 will be described. As shown in FIGS. 7 and 8, the transmission shaft extending forward from the rear engine 4 is inserted into the mission case 10, and the universal joints 11 and 11 and the drive shaft 12 are inserted from the mission case 10. And connect to the rear wheel differential case 13. A front wheel case is formed integrally with the mission case 10, non-steering front wheels 14 are attached, and a rear wheel diff case 1
A steering type rear wheel 15 is attached to the steering wheel 3. The operation unit 1 is provided with an operation lever 26 for switching between four-wheel and two-wheel drive modes, and the drive modes are switched by the operation lever 26. On the other hand, as shown in FIG. 7, the gear case 28 incorporating the one-way clutch 27 can be replaced with the set universal joints 11 and 11 and the drive shaft 12. The rear wheel 15 is set to rotate about 5% slower than the front wheel 14 by the two gears 28A and 28B.
When it rotates at a higher speed than that by the action of 7, it idles. Therefore, during normal flat traveling or turning, the rear wheels 1
5 rotates at substantially the same speed as the front wheels 14, so that the front wheels 14
It is possible to suppress the lawn shaving phenomenon caused by the rear wheels 15 by performing a two-wheel drive traveling only with the
Automatically switches to 4-wheel drive mode. Next, the structure of the driving unit 1 will be described. As shown in FIG. 5, a diff lock operation tool 16 is arranged on the left side and a shift operation tool 17 is arranged on the right side at the foot of the driving unit 1. The speed change operation tool 17 is an operation tool for operating a hydrostatic continuously variable transmission (hereinafter referred to as HST) 18 provided in the mission case 10.

As shown in FIGS. 4 and 5, the diff lock operation tool 16 is pivotally supported on a channel type frame 16A which can be swung around the axis X and one rising plate portion of the channel type frame 16A. It is composed of a pedal portion 16B and a restraining piece 16C which is laterally projected on the other rising plate portion. The front wheel diff lock mechanism 19 is attached to the other rising plate.
An operation wire 22 is connected to the. As shown in FIG. 1, the speed change operation tool 17 includes a channel type frame 17A that is swingable around an axis Y, and the channel type frame 1
Pedal part 17B pivotally supported on one of the rising plate parts of 7A
And the transmission shaft 2 extended to the vicinity of the diff lock operation tool 16
It consists of a check metal fitting 17C which is loosely fitted to 0. An operation wire 21 to the HST 18 is connected to the other rising plate portion. The check metal fitting 17C is integrally swingable by a coil spring 23 whose one end is engaged with the speed change shaft 20 and the other end of which is held by the check metal fitting 17C, and is relatively rotatable against the spring force of the coil spring 23. It is loosely fitted in 20. A downward concave portion 17D is formed at the upper end of the restraining metal member 17C, and the restraining piece 16C is inserted into the downward concave portion 17D.

With the above-described structure, the speed change operation tool 17
The linkage between the diff lock operation tool 16 will be described. As shown in FIG. 2, when the differential operation pedal 17 is set to the neutral position N and the differential lock pedal portion 17B is depressed, the restraining piece 16C enters the downward recess 17D and the differential lock operation tool 16 is switched to the differential lock engaged position. . On the other hand, as shown in FIG. 3, when the speed change operation tool 17 is at a speed setting position outside the neutral position N, the check piece 16C contacts the upper end of the check metal fitting 17C other than the portion in which the downward recess 17D is formed. , The movement of the diff lock operation tool 16 to the diff lock entering position is restricted.

As a result, the diff lock operation can be performed only when the speed change operation tool 17 is in the neutral position N, and damage to the diff lock mechanism 19 is avoided. However, the downward recess 17
If the width of D is widened, the check piece 16C can be engaged with the downward recess 17D even at the shift position deviated from the neutral position N, and the diff lock operation can be performed even in the low speed range.

As shown in FIG. 2, when the shifting piece 16C is depressed with the check piece 16C engaged in the downward recess 17D of the check fitting 17C, the check piece 16C is depressed.
The gear shift shaft 20 rotates integrally with the gear shift operation tool 17 against the spring force of the coil spring 23 while maintaining the state of being engaged with the downward recess 17D, and gear shift operation is possible.

Another structure for linking the gear shift operation tool 17 and the diff lock operation tool 16 will be described. As shown in FIG.
The check metal fitting 17C is fixed to the speed change shaft 20, and the check metal fitting 17C is not formed with a recess such as the downward recess 17D. On the other hand, the check piece 1 is vertically provided on the other frame of the channel type frame 16A of the diff lock operation tool 16.
Attach 6C. Even in a state in which the gear shift operation tool 17 is gear-shifted from the neutral position N by a certain angle L to a low speed range,
It is possible to operate the diff lock operation tool 16 to the diff lock position. When operated at a speed higher than the low speed range, the check piece 16C contacts the upper end of the check fitting 17C, and the diff lock operating tool 16 cannot move to the diff lock entering position. With such a structure, the diff lock operation can be performed even in a constant low speed range.

[Other Embodiments] A linking structure between the check metal fitting 17C and the speed change shaft 20 will be described. As shown in FIG. 10, the first cam body 17F is fixed to the speed change shaft 20 by a pin 24 so that the speed change shaft 20 and the first cam body 17F can rotate integrally and face the first cam body 17F. The second cam body 17E is loosely fitted so that both cam bodies 17F and 17E can be engaged and disengaged by the biasing spring 25, and the restraining metal member 17 is fixed to the second cam body 17E. With such a configuration, even when the restraining piece 16C and the restraining metal fitting 17C are in the engaged state, the gear shift operation tool 1
When the gear shift operation of 7 is performed, the cam engagement of the first and second cam bodies 17F and 17E is disengaged against the urging force of the urging spring 25, and the first cam body 17F, that is, the gear shift operation tool 17 is held by the check metal fitting 17C.
Rotate relative to. Checking piece 16C and checking metal fitting 17C
And is called a restraint mechanism.

The coil spring 23 that links the speed change shaft 20 and the restraining metal fitting 17C, the cam bodies 17E and 17F and the biasing spring 25 described above, and the restraining metal fitting 17C are formed of an elastic body. The structure that allows the speed change operation tool 17 to perform a speed change operation even in the diff lock state is generally referred to as a structure in which the speed change operation tool is set to a high speed range in a state where the diff lock operation tool is set to the diff lock on position by the operation of the check mechanism. It is referred to as an elastic accommodation mechanism that allows the moving operation.

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

[Brief description of drawings]

FIG. 1 is a side view showing a state in which a shift lock operation tool can be operated with a shift operation tool in a neutral position.

FIG. 2 is a side view showing a state in which the shift operation tool can be operated to shift while the diff lock operation tool is operated in a diff lock state.

FIG. 3 is a side view showing a state in which the diff lock operation tool cannot be operated in the diff lock state.

FIG. 4 is a perspective view showing a check mechanism for a diff lock operation tool.

FIG. 5 is a vertical cross-sectional rear view showing an arrangement configuration of a diff lock operation tool and a shift operation tool.

FIG. 6 is a plan view showing a pipe replacement structure for an oil cooler.

FIG. 7 is a block diagram showing a transmission structure.

[Figure 8] Overall side view

FIG. 9 is a side view showing a check mechanism for a diff lock operation tool.

FIG. 10 is a rear view showing another embodiment of the elastic accommodation mechanism.

[Explanation of symbols]

 16 Differential lock operation tool 17 Gear change operation tool N Neutral position

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenji Matsuda 64 Ishizukita-machi, Sakai City, Osaka Prefecture Kubota Sakai Factory Co., Ltd. Inside the factory

Claims (1)

[Claims] 1. A speed change operation tool (17) and a diff lock operation tool (16) are provided with the speed change operation tool (17) in a neutral position (N) or in a low speed range of a certain width from the neutral position (N).
The differential lock operating tool (16) is allowed to move to the differential lock-in position, and the shift operating tool (17) prevents the differential lock operating tool (16) from moving to the differential lock position in a high speed range outside the low speed range. With a check mechanism,
The diff-lock operation tool (1
A riding lawn mower provided with an elastic accommodation mechanism that allows the shift operation tool (17) to be moved to a high speed range with 6) set to the diff lock-in position.