JPH0228094Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to the improvement of a traveling type work machine equipped with a brake that automatically operates when the transmission is set to neutral gear, and in particular protects the brake lining.
The purpose is to propose a work machine that provides a comfortable ride when starting. The present invention will be explained in detail below based on drawings showing an embodiment of the present invention in a combine harvester.

FIG. 1 is an external view of a combine harvester according to the invention (hereinafter referred to as the invention machine). In the figure, EG is the engine, DS is the driver's seat, and CC is the operation column located in front of the driver's seat DS. Operation column CC
A switch group SW is attached to the main shift drive system. As shown in Fig. 2, this switch group SW includes switches F3, F2, and F1 for selecting forward 3rd, 2nd, and 1st gears, switches N and N for selecting neutral gear, all of which are push button switches. Consists of switch R for selecting reverse gear, switches F3, F2, F1, N, R
is configured to select one point, so that only the one that is pressed is latched.

Figure 3 shows the hydraulic circuit of the power shift transmission installed in the proposed machine, in which the pressure oil of the hydraulic pump P is transferred from the solenoid valve Va to the hydraulic multi-disc clutches CL1 and CLR via the sequence valve SQ. Solenoid valve Va,
It is designed to be supplied to the clutches CL2 and CL3 via Vb, and further to the hydraulic cylinder 5c. Sequence valve SQ
is for supplying pressure oil to the downstream side when the pressure in the upstream circuit exceeds a certain value. When pressure oil is supplied to multi-disc clutch CL3 (or CL2, CL1, CLR), each clutch is engaged, and a predetermined gear in a gear group (not shown) is engaged to shift to 3rd forward speed (or 2nd forward speed). The vehicle is designed to run in three gears (first speed, forward speed, and reverse).

The solenoid valve Va is a 5-port, 3-position switching type directional control valve, and when its solenoids S ₁ and S _R are demagnetized, it is in the neutral position shown, and the outlet port of the sequence valve SQ and the pump side of the solenoid valve Vb are At the same time, the multi-disc clutches CL1 and CLR are communicated with the tank, and when the solenoid _S1 is energized, they are switched to the switching position, and the multi-disc clutch CL1 is communicated with the sequence valve SQ outlet port. Connect CLR to tank and solenoid valve Vb
Furthermore, when the solenoid S _R is energized, it is switched to the switching position, and the multi-disc clutch CLR is communicated with the outlet port of the sequence valve SQ, while the multi-disc clutch CL1 is communicated with the tank, and in the same manner as above. The oil passage to solenoid valve Vb is sealed off.
The solenoid valve Vb is a 5-port, 3-position switching type directional control valve, and when its solenoids S ₂ and S ₃ are demagnetized, it is in the neutral position shown, and the pump side port and load (multi-disc clutches CL2 and CL3) side All ports are connected to the tank, and when solenoid S ₂ is energized, they are switched to the switching position, and the pump side port and multi-disc clutch CL2 are communicated, while multi-disc clutch CL3 is communicated with the tank, and solenoid S ₃ is energized. Sometimes, on the contrary, the pump side port is communicated with the multi-disc clutch CL3, and the multi-disc clutch CL2 is communicated with the tank. Solenoid _S3 , one of which is selectively energized by such a hydraulic circuit configuration,
By excitation of S ₂ , S ₁ or S _R respectively, CL3, CL2,
CL1 or CLR becomes connected and the aircraft moves forward 3
The vehicle will move forward or backward in 1st, 2nd, and 1st gears.

The solenoid valve V ₀ is a 2-port 2-position directional control valve, and when the solenoid S ₀ is demagnetized, the position is selected and the entire pressure oil is returned to the tank T.
Pressure oil is not supplied to the solenoid valve Va side and the hydraulic cylinder 5c, and the position when the solenoid S ₀ is energized is selected, the oil path to the tank T is blocked, and the entire amount of pressure oil is supplied from the hydraulic pump P to the electromagnetic cylinder. It will be supplied to the valve Va side and the hydraulic cylinder 5c. Solenoid S ₀ is connected to switches F1, F2, F3 and R
When any one of them is pressed, it is excited.

The hydraulic cylinder 5c is used to release the brake 5, and specifically has a structure shown in FIG. 4. That is, a brake drum 5a provided in the transmission system of the drive wheels of the left and right crawlers CR,
Brake shoes 5b, 5b arranged to surround this from two directions on the outer periphery, and a hydraulic cylinder 5c
and a tension spring 5d. The brake shoes 5b, 5b are each pivotally supported at one end, and brought close to each other by a tension spring 5d stretched between the other ends, and a lining 5 attached to the inner peripheral surface
b' and 5b' are pressed against the outer peripheral surface of the brake drum 5a for braking, and when pressure oil is supplied to the hydraulic cylinder 5c, they are separated from each other and the brake drum 5a
is released from the pressure. A parallel circuit of a check valve Vc and a variable throttle valve Vd is interposed in the oil path leading from the hydraulic pump P to the hydraulic cylinder 5c, and pressure oil can be freely supplied from the hydraulic pump P to the hydraulic cylinder 5c. However, hydraulic cylinder 5
The flow rate of the pressure oil returned from c to tank T is controlled by a throttle valve Vd. That is, the brake is released quickly, but the braking operation of the brake is performed slowly.

As mentioned above, the sequence valve SQ is to feed pressure oil to the downstream side when the pressure in the upstream side circuit exceeds the set pressure, so the pressure oil from the hydraulic pump P is first sent to the hydraulic cylinder. 5c to completely release the brake. In this case, complete release means that the brake linings 5b', 5b' and the brake drum 5a are completely separated and are not in contact with each other. Then, the sequence valve SQ maintains the hydraulic pressure in the hydraulic cylinder 5c at the set pressure,
Keep the brake 5 fully released,
After that, supply pressure oil to the solenoid valve Va side.

Also, RL is a relief valve that keeps the pressure in the hydraulic circuit shown in Figure 3 below a certain pressure, and its set pressure is higher than the set pressure of sequence valve SQ, and sequence valve SQ is in communication. After that, when the oil pressure in the circuit shown in FIG. 3 increases to a level higher than the set pressure of the relief valve RL, the relief valve RL is opened and the pressure oil is returned to the tank T. Furthermore, even if a blockage or the like occurs in the circuit and the pressure rises rapidly, the relief valve RL returns the pressure oil to the tank to prevent danger.

The operation of the proposed machine constructed as described above is as follows. When the aircraft is at rest, that is, when the transmission is set to neutral gear, solenoid S ₀ is demagnetized, all pressure oil from hydraulic pump P is returned to tank T, and the hydraulic Pressure oil is not supplied to the cylinder 5c. Therefore, the brake 5 is applied to the linings 5b' and 5 by the tension spring 5d.
b' is pressed against the brake drum 5a, and the drive wheels of the left and right crawlers CR are braked. Therefore, when the switch F1 (or F2, F3, R) is pushed in, the solenoids S ₀ and S ₁ (or S ₂ , S ₃ ,
S _R ) is energized and the solenoid valve V ₀ is in the position,
Pressure oil from the hydraulic pump P is first supplied to the hydraulic cylinder 5c via the check valve Vc, and then the brake 5
releases the brake. And hydraulic cylinder 5
When c is filled with pressure oil and the brake 5 is completely released, the pressure in the circuit increases and the sequence valve
SQ communicates and starts supplying pressure oil to the solenoid valve Va side. Solenoid valve Va (or Vb) is (or,)
Since the position is selected, the pressure oil from the hydraulic pump is supplied to clutch CL1 (or CL2, CL3, CLR).
The air conditioner is supplied to the engine and brought into a joint state, and the aircraft is started and accelerated, and travels in the first forward gear (or the second gear, the third gear, or the rear gear).

After that, when the transmission is set to neutral gear, that is, when switch N is pushed in, solenoids S ₀ and S ₁ (or S ₂ , S ₃ , S _R ) are demagnetized and solenoid valve V ₀ is turned off. position, and the pressure oil in the hydraulic cylinder 5c is returned to the tank T. At this time, since the oil passage is provided with a check valve Vc and a variable throttle valve Vd, the pressure oil in the hydraulic cylinder 5c is gradually returned, thereby performing gentle braking. Then, the pressure oil in the hydraulic cylinder 5c is completely drained from the tank T.
In the state where the flow is refluxed to the brake 5, the tension spring 5
By the action of d, it functions as a parking brake. Note that since the throttle valve Vd can be adjusted, by adjusting its flow rate, it is possible to obtain a braking time of the brake 5 that corresponds to the sense of the driver.

In the above-described embodiment, a hydraulically controlled power shift transmission was used as the transmission, but a selective mesh transmission may also be used.

As detailed above, the traveling type work machine according to the present invention changes the oil path by using the shift solenoid valve to switch the oil path of the pressure oil generated by the hydraulic pump and supplies it to the hydraulically controlled transmission device to change gears. In the traveling type work machine as described above, when a sequence valve is interposed between the hydraulic pump and the gear shift solenoid valve, and the sequence valve is connected between the sequence valve and the hydraulic pump, and the gear stage is set to a neutral gear. The sequence valve includes a braking solenoid valve that is in a first position when the gear is set to the drive stage and a brake that is activated when the braking solenoid valve is in the first position. When the braking solenoid valve is in the second position, pressure oil is supplied to the gear shifting solenoid valve after the brake is completely released, so the brake lining wears out unnecessarily when starting the vehicle. Never. Therefore, the wear of the brake lining is significantly reduced, and the present invention has excellent effects such as providing a comfortable ride without any unpleasant impact when starting the vehicle.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which Fig. 1 is an external view of a combine harvester according to the invention, Fig. 2 is a perspective view of a switching operation section of a transmission, and Fig. 3 is a perspective view of a switching operation section of a transmission.
The figure is a hydraulic circuit diagram for switching control of the transmission and brake control, and FIG. 4 is a schematic configuration diagram of the brake. Va, Vb, V ₀ ...Solenoid valve, SQ...Sequence valve, RL...Relief valve, 5...Brake, 5c
...Hydraulic cylinder, 5d...Tension spring.

Claims (1)

[Scope of Claim for Utility Model Registration] In a traveling type working machine in which pressure oil generated by a hydraulic pump is supplied to a hydraulically controlled transmission device to change the speed by switching the oil path with a speed change solenoid valve. , a sequence valve interposed between the hydraulic pump and the gear shift solenoid valve, and a sequence valve connected between the sequence valve and the hydraulic pump, which is in the first position when the gear gear is set to the neutral gear and is in the travel gear. The sequence valve includes a braking solenoid valve that is in the second position when the braking solenoid valve is set to the first position, and a brake that is activated when the braking solenoid valve is in the first position.
1. A traveling type work machine characterized in that, when the gear shift position is reached, pressure oil is supplied to the speed change electromagnetic valve side after the brake is completely released.