JPS5849857Y2 - Agricultural tractor sudden start prevention device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a sudden start prevention device for an agricultural tractor.

= Agricultural tractors are generally configured to have a rotary working machine attached to their rear part via a three-point linkage mechanism.
When the working machine is attached and lowered into a relatively hard field while rotating the rotary tilling claws, the rear wheels lift up and the tractor is supported by the front wheels and the rotary tilling claws. This may cause the tractor to fly out, a so-called dash.

The present invention solves the above-mentioned conventional drawbacks, and includes a slip detection device for detecting the circumferential speed difference between the front wheels and the rear wheels, a setting device for setting the allowable circumferential speed difference, and a combination of the slip detection device and the setting device. and a blade controller that outputs a control signal when the circumferential speed difference exceeds the allowable circumferential speed difference. The object of the present invention is to provide a sudden start prevention device for an agricultural tractor that can prevent the button from jumping out at the start of or during plowing, thereby ensuring the safety of the operator.

Embodiments of the present invention will be described in detail below with reference to the drawings.

Fig. 1 is a side view of an agricultural tractor, in which 1 is an engine part, 2 is a clutch part, 3 is a traveling transmission part 3a and a PTO transmission part 3b.
is the PTO shaft, 5 is the bundle, 6 is the seat, T is the front wheel, 8
9 is a rear wheel, 9 is a rear axle, and the engine section 1. The clutch section 2 and the transmission section 3 are integrally connected in this order to form the fuselage.

A hydraulic lift 12 operated by a hydraulic switching valve (control valve for hydraulic lift) 11 is installed on the mission case 10 constituting the PTO mission section 3b, and a top link hinge 13 is attached to the rear end of the lift housing of the lift 12. In addition, the rotary work machine B is configured to be attached to the rear of the tractor A using a three-point link mechanism consisting of a top link 14 attached to the top link hinge 13 and a lower link 15.15 attached below the top link hinge 13. It is something.

a lift arm 16 whose base end is engaged with a lifting shaft (not shown) of the hydraulic lift 12;
Lift rods 17, 17 are installed between the tip of the handle 16 and the lower link 15.15, so that the working machine B can be raised and lowered as appropriate.

As described above, the transmission section 3 mentioned above is separated in the front and rear direction, and is divided into a driving mission section 3a and a PTO mission section 3.
The clutch housing 18 which constitutes the clutch part 2 and the traveling transmission part 3a are formed by b.
A side cover 20 having an oil passage (not shown) provided therein is interposed between the transmission case 19 and the transmission case 19.

t, 21 is a power shift valve for controlling the hydraulic clutch type multi-stage transmission mechanism in the transmission case 19;
The valve 21 is fixed to the front upper wall of the transmission case 19.

Furthermore, 22 is an accelerator lever that supplies or stops the supply of operating fuel to the engine 1 and controls the increase/decrease of the fuel injection amount.

By the way, the rotary working machine B is configured to receive input via a bendable power transmission shaft 23 connected to the PTO shaft 4 to rotationally drive the rotary tilling claws 24.
are rotary transmission case 25, gauge wheel 26. Depth adjustment frame 27. It is a side drive type that includes a rotary cover 28 button and a handle-type operating rod 29 for manual adjustment of plowing depth.

Next, as shown in FIG. 2, the slip detection device 30, the setting device 31, the discriminator 32, the amplifier 33, and the electromagnetic switching valve
It also includes an operating device consisting of a hydraulic multi-plate clutch 35 provided on the PTO shaft 4 and the like.

As is clear from the figure, the slip detection device 30 includes:
Front wheel rotation speed detection device 36 that detects the front wheel 70 rotation speed
, a rear wheel rotational speed detection device 37 that detects the rotational speed of the rear wheel 8, and an arithmetic circuit 38 that calculates the circumferential speed difference between the front wheel 7 and the rear wheel 8 by calculating the outputs from both of these devices 36 and 37. It is composed of.

Furthermore, the setting device 31 is for presetting an allowable circumferential speed difference, and is configured to set a reference voltage corresponding to the circumferential speed difference and output this reference voltage to the next stage circuit. .

Further, the discriminator 32 compares and determines the output voltage value from the width detection device 30 and the reference voltage value from the setting device 31, and determines whether the actual circumferential speed difference between the front and rear wheels 7.8 exceeds the allowable circumferential speed difference. A control signal is output when the output voltage value from the device 30 becomes larger than the reference voltage value.

Further, the amplifier 33 amplifies the output of the AIJi 32 and excites the solenoid 34a of the electromagnetic switching valve 34.

This value should be sufficient for . Next, on the discharge side of the constant displacement hydraulic pump 39, a center bypass type 3-position 3-port electromagnetic switching valve 34 having solenoids 34a and 34b is provided.
At the same time, a relief valve 41 is connected between the discharge side of the hydraulic pump 39 and the tank 40, and the switching valve 3
The actuator port A of No. 4 is communicated with an oil passage 42 formed in the PTO shaft 4.

Next, a rear connecting shaft 46 is mounted on the internal upper partition wall 10a of the mission case 10 and the bearing cover 43 via bearings 44 and 45, and a small-diameter regular gear (PTO pinion) 47 is attached to this shaft 46. The key is engaged.

Further, the shaft 46 is linked to a power transmission element in the traveling transmission section a via a coupling 48 and a front connecting shaft 49.

Furthermore, a bearing 50 is provided in the center of the mission case 10.
, 51, which is parallel to the shaft 46.
A hydraulic multi-plate clutch 35 is installed on the O-shaft 4.

This hydraulic multi-disc clutch 35 includes a clutch gear 54 rotatably loosely fitted to the PTO shaft 4 via a bearing 53, and a PTO
A transmission body 55 key-fitted to the shaft 4, an actuator 56 inserted into the cylinder portion of the transmission body 55, a multi-disc clutch 57 provided between the actuator 56 and the clutch gear 54, and the actuator 56. An oil passage is formed in the transmission body 55 to allow the oil passage 42 in the PTO shaft 4 and the cylinder portion to communicate with each other.

Note that 59 in FIG. 2 is a switching device for turning on the hydraulic multi-disc clutch 35.

The present invention is constructed as described above, and one solenoid 34 of the electromagnetic switching valve 34 is connected via the switching device 59.
When b is excited, the valve 34 is switched and the hydraulic pump 39
The hydraulic oil is supplied to the cylinder portion of the transmission body 55 via the pump port P of the switching valve 34, the actuator port A, and the oil passage 42 formed in the PTO shaft 4.

Therefore, the actuator 56 inserted into the transmission body 55
presses the shaft-moving multi-disc clutch 57 against each other against the spring 58, so that the rotational force of the continuous mesh gear 470 is transferred to the clutch gear 54. P via the multi-disc clutch 57 button and transmission body 55
It is transmitted to the TO axis 4.

When the PTO shaft 4 rotates in this manner, the rotation of the shaft 40 is transmitted to the rotary transmission case 2 through the bendable transmission shaft 23.
5, the tilling shaft rotates and the rotary tilling claws 24 rotate in the direction of the arrow in FIG.

Also, while rotating the tilling claw 24 of the rotary work machine B,
When the working machine B is lowered into a relatively hard field and the rear wheels 8 lift up and the tractor is supported by the front wheels 7 and the rotary tilling claws 24, the tractor is moved by the rotary tilling claws 2.
4 (the number of rotations of the tilling claws is faster than the number of rotations of the rear wheels 8), the front wheels 70 circumferential speed becomes faster than that of the rear wheels 8, and the difference in circumferential speed between them becomes larger than the allowable peripheral speed difference.

First, since the output voltage value from the slip detection device 30 becomes larger than the reference voltage value from the setting device 31, the discriminator 3
2 outputs a control signal, which is amplified by an amplifier 33 and then applied to the other solenoid 34a of the electromagnetic switching valve 34.

In this way, when the solenoid 34a is energized, the electromagnetic switching valve 34 is switched in the opposite direction to that described above, and the transmission body 5
The cylinder portion of No. 5 is communicated with the tank 40 via the extraction passage 42, the actuator port A of the switching valve 34, and the tank port T, and the actuator 56 provided in the transmission body 55 is pushed back by the spring 58, clutch 3
5 is turned off and the rotation of the PTO shaft 40 is stopped, the hydraulic oil in the cylinder section is turned off and the PTO shaft 40 is turned off.
The water is returned to the tank 40 via the .

As mentioned above, when a phenomenon occurs in which the tractor is supported by the front wheels 7 and the rotary tilling claws 24, the rotation of the PTO shaft 40 is stopped, and therefore the rotation of the tilling claws 240 of the rotary work machine B is also stopped. It is possible to prevent a tractor from flying out and ensure operator safety.

In the above embodiment, a hydraulic multi-plate clutch 35 is installed on the PTO shaft 4, and when the difference in circumferential speed between the front and rear wheels 7 and 80 exceeds the allowable circumferential speed difference, the clutch 35 is turned off and the PTO is directly activated. Although the configuration is configured to stop the rotation of the shaft 40, it may be configured such that the output signal from the amplifier 33 drives the operating device to turn off the main clutch, thereby indirectly stopping the rotation of the PTO shaft 40. .

Alternatively, the hydraulic lift 12 may be operated to raise the working machine B when the circumferential speed difference between the front and rear wheels 7, 8 exceeds a permissible circumferential speed difference.

As is clear from the above embodiments, the present invention includes a slip detection device 30 that detects the circumferential speed difference between the front wheel 7 and the rear wheel 8, a setting device 31 that sets the allowable circumferential speed difference, and a button of the slip detection device 30. The front and rear wheels 7
, 80 and a discriminator 32 that outputs a control signal when the circumferential speed difference exceeds the allowable circumferential speed difference, and the electromagnetic switching valve 34 and the hydraulic multi-disc clutch 35 are
This device is configured to stop the rotation of the PTO shaft 4 by driving an operating device such as the PTO shaft 4, and has the effect of preventing the operator from jumping out at the start of tilling or during tilling, and ensuring the safety of the operator. It is something to play.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view of an agricultural tractor showing a divided embodiment of the present invention, and FIG. 2 is a system diagram showing a sudden start prevention device. 4...PTO axis, 7...front wheel, 8...rear wheel, 30
...Slip detection device, 31...Setting device, 32...
Discriminator, 34... Solenoid switching valve (operating device), 35...
・Hydraulic multi-plate clutch (operating device).

Claims (1)

[Scope of utility model registration request] A slip detection device detects the circumferential speed difference between the front wheels and the rear wheels, a setting device sets the allowable circumferential speed difference, and the signals from the slip detection device and the setting device are compared and determined, and the difference in circumferential speed is determined as the allowable circumferential speed. A discriminator that outputs a control signal when a difference is exceeded, and a control signal from the discriminator is used to drive an operating device to stop the rotation of a PTO shaft. Prevention device.