JPH0531507U - Tractor hydraulic lift device - Google Patents

Abstract

(57) [Summary] [Purpose] The hydraulic piping is easy and can be made short and compact with a small number, and the hydraulic piping does not get in the way during machine maintenance. An object of the present invention is to provide a hydraulic lift device for a tractor that can be used as lubricating oil for gears and the like. [Structure] Each valve 4 for tractor control is attached to a hydraulic case 3 fixed on a transmission case 1.
While installing 5, 6 and 7 intensively, each valve 4,
The return oils 5, 6 and 7 are returned to the transmission case 1 via the hydraulic case 3.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a hydraulic lift device for an agricultural tractor.

[0002]

[Prior Art]

 Many agricultural tractors are equipped with a tilling depth control device that automatically controls the working depth during rotary tilling work, and a horizontal control device that keeps the working posture of the working machine horizontal regardless of the tilt of the machine. Also, the one equipped with a front wheel speed-increasing device that rotates the front wheels at high speed when turning the headland and suppresses smooth and speedy turning and headland damage as much as possible is also in practical use. In the field of tractors as well, high functionality and high quality with various automatic control devices are increasing.

The various tractor control devices as described above generally detect the working posture and working state of the working machine and the front wheel turning angle of the working machine by a detection means such as a sensor or potentiometer, and the detection signal is sent from a microcomputer. To control the control hydraulic valves, and thereby change the flow path of the pressure oil from the hydraulic pump to operate the hydraulic cylinders provided in each part of the machine. Many.

[0004]

[Problems to be solved by the device]

 However, in most of the conventional systems, the control hydraulic valves were distributed and installed in various parts of the machine, so the hydraulic piping was inevitably complicated and diversified. There was a problem that it became difficult to do.

[0005]

[Means for Solving the Problems]

 The present invention is intended to solve such a problem, and in a hydraulic lift device for a tractor, in which a hydraulic case having a built-in hydraulic cylinder for vertically rotating a lift arm is fixed on a transmission case. The essence is that the tractor control hydraulic valves are centrally installed in the case, and the return oil of each valve is returned to the inside of the transmission case via the hydraulic case.

[0006]

[Action]

 According to the hydraulic lift device for a tractor according to the present invention, since each hydraulic valve is concentrated and installed around the hydraulic case, the hydraulic piping is easy and compact, and the hydraulic piping interferes with maintenance. Because there is no such thing, maintenance of each part of the aircraft becomes easy. In addition, the return oil from each hydraulic valve is returned to the transmission case via the hydraulic case, so that the return oil piping is as short as possible, and the gears and bearings located above the transmission case are efficient. Be lubricated.

[0007]

【Example】

 A configuration of the present invention will be described with reference to an embodiment shown in the drawings. A transmission case (rear transmission case) 1 is integrally fixed to the upper surface thereof with a hydraulic case 3 having a built-in hydraulic cylinder S for elevating and lowering a working machine connected to a lift arm 2. Hydraulic valves for tractor control are centrally mounted on the hydraulic case 3. That is, one flow dividing valve 4 and a hydraulic valve 5 for horizontal control are provided on one side surface of the hydraulic case 3 (on the right side of the machine body traveling direction), and the other flow dividing valve 6 and a hydraulic valve for controlling the working depth are provided on the other side surface. 7 are arranged such that the flow dividing valves 4 and 6 are located on the front side and are distributed to the left and right in a well-balanced manner. The one flow dividing valve 4 communicates with the hydraulic pump 8 and the other flow dividing valve 6 communicates with the hydraulic pump 9. It is connected. An electromagnetic valve 10, a sequence valve 11, and a pressure reducing valve 12 are incorporated in the flow dividing valve 6, and the oil (pressure of one hydraulic pump 8 among the hydraulic pumps 8 and 9 driven by an engine not shown) is As shown in the hydraulic circuit diagram of FIG. 5, oil is supplied to the lift rod cylinder 13 for horizontal control and the hydraulic cylinder 14 for plowing depth control via the flow dividing valve 4. Further, the pressure oil of the other hydraulic pump 9 is constantly supplied to the hydraulic cylinder 16 for the power steering device 15 via the flow dividing valve 6, but when the front wheels have a turning angle of a predetermined angle or more when the tractor turns, the Is detected, the electromagnetic valve 10 is automatically switched, and a part of the pressure oil supplied to the hydraulic cylinder 16 of the power steering device 15 expands and contracts the operating cylinder 18 of the front wheel speed increasing device 17 via the electromagnetic valve 10. It has become like this. The flow dividing valve 4 has a suction port 19 and a discharge port 20, and the flow dividing valve 6 has a suction port 21, a discharge port 22 to the power steering device 15 and a discharge port 23 to the front wheel speed increasing device 17. Further, each hydraulic valve has a tank port, and the return oil of each valve is introduced into the hydraulic case 3 and is arranged from the hydraulic case 3 into the transmission case 1 from above to the upper layer portion in the mission case 1. The gears and bearings (not shown) are sprinkled and returned. Immediately after the return oil from the diversion valve 4 is used as the lubricating oil of the piston rod of the hydraulic cylinder S for lifting the working machine via the oil passage 3a of the hydraulic case 3 and the pipe P, the oil below the hydraulic case 3 is used. The return oil from the diversion valve 6 and the hydraulic valve 7 for controlling the working depth is returned to the transmission case 1 via the oil passages 3b and 3c of the hydraulic case 3. Therefore, the number of hydraulic pipes is as small as possible and can be kept short. The return oil of the power steering device 15 is returned to the lower part of the center case 24. H is a hydraulic hose and 25 is a valve mounting bolt.

Now, FIG. 3 illustrates a power transmission structure to the front wheels. In this structure, the power to the high-speed drive gear 26 is connected and disconnected by a 2WD / 4WD switching operation lever (not shown), and the cylinder 18 is used in the 4WD use state (state shown in FIG. 3) in the field. When pressure oil is supplied to the cylinder 18, the cylinder 18 moves to the right in the drawing against the spring 28 of the wet multi-plate clutch 27 and becomes the clutch “contact”, and the fixed gear 30 of the differential pinion shaft 29 → high speed drive gear 26 → high speed. The power is transmitted to the output shaft 32 in the order of the driven gear 31 and the multi-plate clutch 27, so that the front wheels are accelerated (state shown below the center of the output shaft 32 in FIG. 3). If the front wheel has a cutting angle of a predetermined angle or less, pressure oil is not supplied to the cylinder 18, the multi-plate clutch 27 is held in the "disengaged" state by the elastic force of the spring 28, and the fixed gear 30 → Intermediate shaft 33 → Low speed drive gear 34 → Low speed driven gear 35 → Steel ball 36 is transmitted to the output shaft 32 in this order, and the normal 4WD state (the front and rear wheels are approximately the same peripheral speed) is reached (from the output shaft center). (State shown above). 37 is a transmission shaft to the front wheels.

[0009]

[Effect of the device]

 Since the present invention is configured as described above, it is possible to make the hydraulic piping easy and compact, and to prevent the hydraulic piping from interfering with maintenance like the conventional one in which hydraulic valves are distributed throughout the machine. Maintenance of each part of the fuselage is easy and the return oil of each valve is returned to the transmission case via the hydraulic case, so the number of pipes can be minimized and shortened and the upper layer of the transmission case It is possible to efficiently use the return oil of each valve to lubricate the parts such as gears and bearings located in the parts where lubrication oil is apt to run short. In addition, the one in which the hydraulic valves are distributed to the left and right of the hydraulic case has the advantages that the left and right balance of the hydraulic case is good and the assembly / disassembly performance is good.

[Brief description of drawings]

FIG. 1 is a plan view of a hydraulic case equipped with the present invention.

FIG. 2 is a sectional side view of a front wheel speed increasing device.

FIG. 3 is a sectional side view showing a structure for transmitting power to the front wheels.

FIG. 4 is a side view of a hydraulic case.

FIG. 5 is a hydraulic circuit diagram of the present invention.

FIG. 6 is a cross-sectional plan view of a hydraulic case.

[Explanation of symbols]

 1 Transmission case 3 Hydraulic case 4 One-way shunt valve 5 Horizontal control valve 6 Other shunt valve 7 Cultivation depth control valve 17 Front wheel speed increasing device 24 Center case

Claims (4)

[Scope of utility model registration request] 1. A hydraulic lift device for a tractor, wherein a hydraulic case having a hydraulic cylinder for vertically rotating a lift arm is fixed on a transmission case, and a tractor control hydraulic valve is centrally mounted on the hydraulic case. A hydraulic lift device for a tractor, wherein return oil of each valve is configured to be returned to the inside of a transmission case via a hydraulic case. 2. The hydraulic lift device for a tractor according to claim 1, wherein the hydraulic valve is a tilling depth control valve, a horizontal control valve, or a control diversion valve. 3. One of the flow dividing valve and the horizontal control valve is arranged on one side of the hydraulic case, and the other of the flow dividing valve and the working depth control valve is arranged separately on the other side. Hydraulic lift device for the described tractor 4. The tractor hydraulic lift system of claim 1, wherein each valve comprises a tank port.