Combine harvester hydraulic control circuit

Abstract

The present invention aims to provide a combine harvester equipped with a threshing device that can maintain the horizontal position of the machine even when the field surface is uneven, by ensuring that the hydraulic control device operates properly and the machine remains level during harvesting. [Solution] In a combine harvester hydraulic control circuit that distributes the hydraulic output of a hydraulic pump 1 driven by an engine 23 to a first pressurized oil supply passage P1 leading to the work hydraulic circuit W1 and a second pressurized oil supply passage P2 leading to the vehicle control circuit W2 using a flow divider valve 37, the first pressurized oil supply passage P1 is connected to the vehicle control circuit W2 via a surplus supply passage P3 of the flow divider valve 37 that divides the oil to the harvesting lifting cylinder 5a and the auger lifting cylinder 5b, and the pressurized oil supplied to the left electromagnetic rolling switching valve 4c, the right electromagnetic rolling switching valve 4d and the electromagnetic pitching switching valve 4e is controlled by a sensor electromagnetic switching valve 34 provided in the vehicle control circuit W2.

Claims

1. In a hydraulic control circuit for a combine harvester, the hydraulic output of a hydraulic pump (1) driven by an engine (23) is distributed by a flow divider (37), and pressurized oil is supplied from a first pressurized oil supply passage (P1) toward the work hydraulic circuit (W1) to the harvesting lifting cylinder (5a) and the auger lifting cylinder (5b), and distributed from a second pressurized oil supply passage (P2) toward the vehicle control circuit (W2) to the left and right rolling cylinders (5c, 5d) and the pitching cylinder (5e), ​​wherein an electromagnetic three-way switching valve (35) is provided in the first pressurized oil supply passage (P1), and the surplus supply passage (P3) of the electromagnetic three-way switching valve (35) is connected to the vehicle control circuit (W2), and a sensor electromagnetic switching valve (34) provided in the vehicle control circuit (W2) controls the pressurized oil supplied to the left electromagnetic rolling switching valve (4c), the right electromagnetic rolling switching valve (4d), and the electromagnetic pitching switching valve (4e).

2. A hydraulic control circuit for a combine harvester, which distributes the hydraulic output of a hydraulic pump (1) to a first pressurized oil supply passage (P1) leading to a work hydraulic circuit (W1) and a second pressurized oil supply passage (P2) leading to a vehicle control circuit (W2) using a flow divider valve (37), is characterized in that a flow divider switching valve (40) is provided such that the flow rate of the second pressurized oil supply passage (P2) is smaller than the flow rate of the first pressurized oil supply passage (P1).

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