JPH0318271Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to work vehicles such as lawn mowers, and more specifically, the present invention is directed to a work vehicle such as a lawn mower that stops the vehicle from moving with a simple operation, and
The present invention relates to a technique for maintaining the stopped state.

[Conventional technology]

Conventionally, as a technique for stopping the running of the vehicle body as described above and maintaining the stopped state, there is a technique disclosed in Japanese Utility Model Application Publication No. 56-118132 or Japanese Utility Model Application Publication No.
There are those shown in each publication No. 56-118131,
In the former of these citations, when the gear shift operating tool is set to neutral, the parking brake is operated to the braking position by energizing the solenoid.
In addition, in the latter of the references, when the operator selects the neutral gear shift state, hydraulic oil for gear shift is supplied to a pair of brakes for steering control, and as a result, both brakes are in the braking state. is configured to reach.

[The problem that the idea attempts to solve]

Now, considering the two cited examples mentioned above, in each of the cited examples, the brakes function automatically when the gear shift operation system is set to neutral, so when parking the vehicle, a special operation is required to maintain the stopped state of the vehicle. Although it is unnecessary, in the former of the cited examples, the brakes are operated by energizing the solenoid, so it is not suitable for long-term parking, and moreover, it is not suitable for parking the vehicle for a long time. If the voltage is low, braking may be insufficient. In addition, in the latter of the cited examples, the brake reaches a braking state by supplying pressure oil, so there is a disadvantage that braking force cannot be sustained for a long time with the engine stopped.

An object of the present invention is to rationally construct a work vehicle that can perform braking with as simple an operation as possible and maintain the braking state for a long time even when the engine is stopped.

[Means to solve the problem]

The features of the present invention are that the driving gear change operating tool is provided so that the driving gear can be returned to the neutral position by the driving brake operating tool, and the driving brake device, which is biased toward the braking state, is driven by the engine. A mechanism that operates and maintains the brake release state using pressure oil from a hydraulic pump that is operated is automatically set to an activated state so that the mechanism is maintained in an activated state only when the traveling speed change operating tool is at a position other than a neutral speed change position. The function and effect are as follows.

[Effect]

According to the above feature, when driving by operating the travel gear change operation tool, the mechanism for operating and maintaining the braking device in the brake release direction is in the operating state, so the braking device is in the non-braking state, and even during driving, When the travel speed change operating tool is operated, the mechanism reaches a non-operating state at the same time as the travel speed change operating tool returns to the neutral position, so that the braking device applies a braking force.

Furthermore, when applying braking force in this manner, pressure oil supply from a hydraulic pump is not required.

[Effect of idea]

Therefore, instead of operating a gear shift operating tool, a dedicated operating tool for braking is operated, so braking can be performed quickly and with a simple operation that is unlikely to cause erroneous operation, and even when the engine is stopped. A work vehicle that can maintain a braking state for a long period of time has been rationally constructed.

〔Example〕

Next, embodiments of the present invention will be described based on the drawings.

As shown in FIGS. 1 and 2, front wheels 3, 3 for steering are provided whose direction is changed by a hydraulic cylinder 2 as the steering handle 1 is operated, and the front wheels 3, 3 for steering are changed by a differential device 4. Left and right rear wheels 5, 5 are provided for dynamic rotation, and a hydraulic continuously variable transmission device 6 for driving that outputs to the differential device 4 is interlocked and connected to an engine 7 at the front of the vehicle body via a transmission shaft 8. The mower 9 is attached to the lower part of the lower abdomen of the vehicle body so as to be movable up and down via a pair of upper and lower swing links 10, and a hydraulic cylinder 12 for swinging the mower lifting operation lever 11 is provided. The mower is used for mowing lawns, etc.

As shown in FIG. 3, as the gear is oscillated from the neutral shift position N to the forward forward shift range F and the backward reverse shift range R, the axial plunger type hydraulic pump 6A in the continuously variable transmission 6 is tilted. A travel shift lever 13 is provided as a travel shift operating tool for changing the plate angle, and a slide type cam plate 14 for pressing and swinging the shift lever 13 to the shift neutral position N is provided with a foot pedal 1 as a travel brake operating tool.
5, is interlocked and connected via a link mechanism 16 so that it is moved to the side of the pressing operation by the depression;
A spring 17 is provided to urge the pedal 15 back upward, and a limit switch 18 is provided which is pressed open only when the shift lever 13 is at the neutral shift position N.

Further, as shown in FIGS. 2 and 4, a travel braking roller 21 that locks the gear 20 fixed to the output shaft 19 of the continuously variable transmission 6 is attached to the piston 22, and A spring 23 that biases the roller 21 toward the locking side is provided to act on the piston 22, and the pressure oil of the working device driving pump 24 attached to the engine 7 is connected to the piston. An oil passage 26 for supplying oil to maintain the roller 21 in the disengaged state is provided in the storage case 25, and an electromagnetic two-position switching valve 27 is provided in the oil passage 26 to cut off and cut off the supply of pressure oil.
It is provided with elastic bias on the blocking side. Then, the switching valve 27 and the limit switch 18 for detecting the shift lever position are connected so that the valve 27 can be operated to the communicating state when the shift lever 13 is at a position other than the shift neutral position N, and the piston 2
2 is formed with an orifice 28 for flowing pressure oil, and
An oil passage 29 is formed in the piston storage case 25 to return oil from the orifice 28 into the transmission case M. 2
1 engages with the gear 20 to perform travel braking, and is configured such that the travel braking state can be maintained until the shift lever 13 is operated to a position away from the shift neutral position N. There is.

In the figure, 30 is a key-operated main switch connected in series with the limit switch 18.

To implement the present invention, the traveling braking device is as follows:
In addition to providing the roller 21 that locks the gear 20, various known devices such as a disk type or a drum can be used, but as described in the embodiment, the hydraulic continuously variable transmission 6 is equipped as a traveling transmission. In some cases, the hydraulic pump 6 in the continuously variable transmission 6
Since A has the function of braking travel by hydraulic lock in the neutral gear shift state, sufficient braking force can be obtained just by providing the locking roller 21 as in the embodiment.

In addition to the hydraulic continuously variable transmission 6, various known devices are used as the traveling transmission, such as a belt-type continuously variable transmission and a type in which a multi-disc clutch for shifting is operated on and off by a hydraulic cylinder. can.

In addition, as an operation maintenance mechanism for the braking device,
Although it is preferable to use a combination of the piston 22 and the electromagnetic valve 27 as in the embodiment, various other configurations are possible.

Further, the present invention can be applied to various work vehicles such as tractors in addition to grass mowers.

[Brief explanation of drawings]

Figure 1 is a side view of the mower, Figure 2 is a schematic diagram showing the transmission system and hydraulic piping system, Figure 3 is a diagram of the relationship between the gear shift lever and the foot pedal, and Figure 4 is the mounting part of the travel braking roller. FIG. 13... Operating tool for traveling speed change, 15... Operating tool for traveling braking, 20, 21... Braking device for traveling, 2
2, 27... Running maintenance mechanism, 7... Engine, 2
4...Hydraulic pump, N...Shift neutral position.

Claims (1)

[Scope of utility model registration request] The driving gear change operating tool 13 is connected to the driving brake operating tool 15.
The traveling brake devices 20 and 21 are provided so as to be operable to return to the gear shift neutral position N by the brake system, and are energized to the braking state by the pressure oil from the hydraulic pump 24 driven by the engine 7. Mechanisms 22 and 27 for operating and maintaining the brake release state can be automatically switched between an active state and a non-active state so that the mechanisms 22 and 27 for operating and maintaining the brake release state are maintained in the active state only when the travel shift operation tool 13 is at a position other than the neutral shift position. A work vehicle set up in.