JP2012201481A - Hydraulic device for working vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic device for a working vehicle capable of accurately controlling an oil quantity, and capable of using a flow control means in common even when a required oil quantity is different.SOLUTION: This hydraulic device 1 for the working vehicle includes a pump 120 for supplying a hydraulic fluid to an actuation control valve 300 for controlling hydraulic fluid pressure of hydraulic actuators C1-C6, and includes a flow rate control valve 220 arranged in an oil passage for supplying the hydraulic fluid to the actuation control valve from a hydraulic pump and bleeding off a flow rate of a predetermined flow rate or more, and a variable throttle mechanism 210 arranged between the flow rate control valve and the actuation control valve and capable of adjusting the oil quantity.

Description

  The present invention relates to a hydraulic apparatus that supplies hydraulic pressure to hydraulic equipment mounted on a work vehicle, and in particular, can control the oil amount with high accuracy and can control the flow rate even when the required oil amount is different. It is related to what can be shared.

  For example, a work vehicle such as a garbage collection vehicle is provided with a hydraulic device such as a dust collection device on the vehicle. In such a hydraulic device, each valve and actuator are operated by hydraulic pressure generated by driving a hydraulic pump by a rotational force that obtains engine power through a power take-off (PTO) mechanism or the like.

In the case of a garbage truck, a hydraulic cylinder, a hydraulic motor, and the like are controlled by a proximity switch, and are automatically driven when an operator presses one button.
The position before the button is pressed is called the loading completion position, and the time when the button is pressed from this position to return to that position again (the loading operation is completed and then returned to that position) is called one cycle second. ing.
This one-cycle second is controlled so that the engine speed is adjusted (amplified) by using an electronic governor prepared on the chassis side so as to be a fixed time.
For this reason, when the operator wants to collect, all the actuators work automatically by simply pressing the loading button, and the operation of one cycle is completed over a preset number of seconds. Yes.

For example, in the case of a garbage truck, the setting range of the above-described one cycle second is determined by an organization to which the manufacturer belongs, and the manufacturer has a structure in which the user cannot easily change the set number of seconds. , To ensure that users are not allowed to make changes beyond the scope.
However, as described above, since the power source of the hydraulic pump is a PTO mechanism, the user deliberately depresses the accelerator pedal at the time of loading to amplify the engine speed and advance one cycle second. was there.
This is presumed to be because it is possible to shorten the loading work time if the cycle mechanism is faster and the loading mechanism operates faster. However, if the cycle time is made too early, it is difficult to ensure safety. There is concern about becoming.

In order to prevent such a user from shortening one cycle second, for example, a plunger pump or the like is used as a hydraulic pump, and the pump structure itself does not supply a fixed flow rate or more.
In the garbage truck, the hydraulic pump is driven by the rotational speed of the PTO mechanism, and one cycle second is determined according to the discharge amount. In the case of a commonly used gear pump, the gear rotates once. The discharged amount to be discharged is structurally determined. However, in the case of a plunger pump, it is possible to adjust the pump discharge amount with respect to the rotational speed of the PTO mechanism, and even if the user steps on the accelerator, the flow rate is proportional to the engine rotational speed. It is possible to prevent the increase.
However, since the plunger pump has a complicated structure, there are many troubles, and there are problems such as large size and high cost. In addition, there are vehicles in which it is difficult or impossible to mount a plunger pump, such as an electric garbage collection vehicle equipped with an electric motor that requires a large space as another drive source of a hydraulic pump due to the size etc. .

On the other hand, for example, Patent Document 1 describes a technique for making a flow rate from a pump constant by using a flow rate control device (flow regulator) instead of a pump.
In the technique described in Patent Document 1, a check valve is provided so as to bleed off when a flow rate exceeding a predetermined flow rate flows in the discharge circuit. This check valve includes an orifice intervening in the discharge circuit, a branch circuit connecting the discharge circuit upstream of the orifice to the tank, and a pressing force provided by the differential pressure before and after the orifice is set spring force. And a differential pressure valve that opens the branch circuit by opening an area corresponding to the pressing force when the pressure exceeds the range.

JP-A-11-322007

The technique described in Patent Document 1 theoretically bleeds off all the increments for a flow rate above a certain value, but in reality it opens to the branch circuit by the spring force. The amount is controlled, and it is not possible to flow all through this branch circuit for values greater than the control flow rate value.
Moreover, although the technique described in Patent Document 1 is a technique related to a rotating-plate-type garbage collection vehicle, a press-type dust-collecting vehicle that has recently spread requires a larger flow rate than a conventional rotating-plate-type collection vehicle. Therefore, control becomes more difficult.

Furthermore, the required amount of oil differs greatly between the press-type garbage collector and the rotary-plate-type garbage collector, so that it is difficult to drive with the same hydraulic device, resulting in an increase in product types. This was a cause of increased costs.
In the case of adjusting the flow rate by adjusting the flow regulator, the oil amount necessary for an appropriate one cycle second in the garbage truck is calculated and set so that the flow regulator works with the oil amount value. In the technique described in, the adjustment width is extremely narrow because the diameter and spring for reducing the inrush flow rate value are fixed.
For this reason, it is possible to adjust the individual difference by the same type, but when the required oil amount is greatly different as in the rotary plate type and the press type as described above, it is necessary to prepare a different flow regulator depending on the type. was there.
An object of the present invention is to provide a hydraulic device for a work vehicle that can control the oil amount with high accuracy and can share the flow rate control means even when the required oil amount is different.

The present invention solves the above-described problems by the following means.
According to a first aspect of the present invention, there is provided a hydraulic device for a work vehicle including a hydraulic pump that supplies hydraulic oil to an operation control valve that controls an operation hydraulic pressure of a hydraulic actuator, wherein the operation is performed from the hydraulic pump to the operation control valve. A flow control valve that is provided in an oil passage for supplying oil and bleeds off a flow rate equal to or higher than a predetermined flow rate; and a variable throttle mechanism that is provided on the downstream side of the flow control valve in the oil passage and capable of adjusting the oil amount. It is provided with the hydraulic apparatus for work vehicles characterized by these.
According to this, it is possible to arbitrarily vary the amount of oil supplied to the operation control valve by the variable throttle mechanism, and it is not necessary to prepare a different device for each system of the in-vehicle hydraulic device, and the common specification It becomes possible to cope with a plurality of types by the flow rate control device.
For example, in the case of a garbage collection vehicle, it is possible to cope with both a press type and a rotary type by a common flow control device.

The invention according to claim 2 is provided with a relief valve that is provided between the variable throttle mechanism and the operation control valve in the oil passage and is capable of controlling pressure. This is a vehicle hydraulic device.
According to this, even when a predetermined pressure or more is generated due to a failure of a control unit such as a valve, a motor driving a pump, or an engine, it can be converted into a safe pressure or oil amount.

The invention according to claim 3 is the work vehicle hydraulic device according to claim 1 or 2, wherein the variable throttle mechanism is capable of blocking the oil passage.
According to this, since the amount of oil at the time of maintenance can be made zero, for example, the operation of each actuator can be prevented and the maintenance can be performed safely.

The work vehicle according to any one of claims 1 to 3, wherein the variable throttle mechanism includes a lock mechanism that can be held at a predetermined throttle amount. It is a hydraulic device.
According to this, by providing the lock mechanism, it is possible to prevent the user from operating the variable throttle mechanism to increase the amount of oil in order to speed up the work operation.

The invention according to claim 5 is characterized in that the hydraulic pump drives an electric motor by controlling an inverter using a battery as a power source, and uses the rotational force of the electric motor to drive the hydraulic pump. It is a hydraulic device for work vehicles given in any 1 paragraph to Claim 4.
According to this, even if it is an electric garbage collection vehicle which employ | adopts the electric motor which requires a big mounting space as a drive source of a hydraulic pump, the magnitude | size of the whole system can be made compact.

  As described above, according to the present invention, there is provided a hydraulic device for a work vehicle that can control the oil amount with high accuracy and can share the flow rate control means even when the required oil amount is different. can do.

It is the see-through | perspective perspective view which looked at the vehicle-mounted dust collection apparatus with which the Example of the hydraulic apparatus for work vehicles to which this invention is applied is provided from diagonally back side. It is the see-through | perspective perspective view which looked at the dust collection apparatus of FIG. 1 from the diagonally forward side. It is a figure which shows the structure of the hydraulic circuit of the hydraulic device for working vehicles of an Example. FIG. 4 is an enlarged view of a part IV in FIG. 3, illustrating a configuration of the flow control device. It is sectional drawing of the flow control apparatus of FIG. It is a figure which shows the structure of the operation control valve in the hydraulic circuit of FIG. It is a graph which shows the correlation with the inlet side flow rate and outlet side flow rate of the flow control apparatus in the hydraulic apparatus of FIG.

  The present invention aims to provide a hydraulic device for a work vehicle that can control the oil amount with high precision and can share the flow rate control means even when the required oil amount is different. The problem was solved by providing a flow control valve on the side and a variable throttle mechanism on the downstream side.

Embodiments of a working vehicle hydraulic device to which the present invention is applied will be described below.
In the embodiment, the working vehicle is, for example, an electric dust collecting vehicle that includes a press-type dust collecting device, rotates a hydraulic pump by driving an electric pump, and drives the dust collecting device.
FIG.1 and FIG.2 is the see-through | perspective perspective view which looked at the dust collection apparatus of the Example from the diagonally backward side and the diagonally forward side, respectively.
The dust collecting device 1 is mounted on a truck chassis (not shown) and constitutes a dust collecting vehicle which is a kind of work vehicle.
The dust collecting device 1 includes a body 10, a tailgate hopper 20, a backflow prevention cylinder C1, a lift cylinder C2, an automatic lock cylinder C3, a vertical movement cylinder C4, an oyster cylinder C5, a discharge cylinder C6, and the like.

The body 10 is configured in a box shape in which an opening is provided on the vehicle rear side.
The body 10 is a part in which the collected dust is accommodated.
In addition, a discharge panel (not shown) that pushes out the stored dust to the rear side is provided inside the body 10.

As shown in FIG. 2, a hydraulic oil tank 110 that stores hydraulic oil is provided at the front portion of the body 10.
Above the hydraulic oil tank 110, a filter 150 for filtering the hydraulic oil that returns to the hydraulic oil tank 110 is provided.
In addition, a pump 120 that pressurizes and discharges hydraulic oil is provided at the lower front portion of the body 10.
Further, a flow control device 200 and an operation control valve 300 which will be described later are attached in the vicinity of the center of the front surface of the body 10.

The tailgate hopper 20 is disposed so as to substantially close the rear opening of the body 10.
The tailgate hopper 20 rotates around a hinge provided at the upper end of the opening of the body 10 so that the opening of the body 10 can be opened and closed.
The tailgate hopper 20 includes a loading device that compresses the dust thrown in by the loading panel 21 and pushes it into the body 10.
The loading device scoops up the dust thrown into the lower portion of the tailgate hopper 20 by a loading panel 21 driven along a predetermined locus, and scrapes it into the body 10.

The backflow prevention cylinder C1 is a hydraulic cylinder that performs the backflow prevention panel oystering and reversing operation in order to prevent the backflow of the loaded dust.
The lift cylinder C <b> 2 is a hydraulic cylinder that opens and closes the opening of the body 10 by rotating the tailgate hopper 20.
The automatic lock cylinder C3 is a hydraulic cylinder that drives a lock mechanism that locks the tailgate hopper 20 and restricts relative rotation with respect to the body 10.
The vertical movement cylinder C4 is a hydraulic cylinder that moves the loading panel 21 of the tailgate hopper 20 up and down.
The oyster cylinder C5 is a hydraulic cylinder that performs oystering operation and reversing operation of the loading panel 21.
The discharge cylinder C6 is a hydraulic cylinder that performs discharge and return operations of a discharge panel that pushes and discharges the dust loaded in the body 10 to the vehicle rear side.

The cylinders C1 to C6 described above are driven by a hydraulic circuit described below.
FIG. 3 is a diagram illustrating a configuration of a hydraulic circuit of the working vehicle hydraulic device according to the embodiment.
The hydraulic circuit 100 includes a hydraulic oil tank 110, a pump 120, an electric motor 130, an accumulator 140, a filter 150, a flow control device 200, an operation control valve 300, and the like.

The hydraulic oil tank 110 is a container that stores hydraulic oil that drives the cylinders C1 to C6.
The pump 120 is a pump such as a gear pump that pressurizes and discharges the hydraulic oil stored in the hydraulic oil tank 110.
The electric motor 130 is a power source that controls the inverter 132 using the battery 131 as a power source and drives the pump 120.
The accumulator 140 is a pressure accumulating container that accumulates high-pressure hydraulic oil discharged from the pump 120.
The accumulator 140 is provided between the flow control device 200 and the operation control valve 300.
The filter 150 filters the hydraulic oil that returns from the operation control valve 300 and the flow control device 200 to the hydraulic oil tank 110.
As shown in FIG. 2, the filter 150 is provided in the upper part of the hydraulic oil tank 110.

The flow rate control device 200 controls the flow rate of hydraulic oil sent from the pump 120 to the operation control valve 300.
FIG. 4 is an enlarged view of a portion IV in FIG. 3 and shows a configuration of the flow control device 200.
FIG. 5 is a cross-sectional view of the flow control device 200.
The flow rate control device 200 includes a variable throttle mechanism 210, a flow rate adjustment valve 220, a downstream pressure control valve 230, a throttle 240, and the like in a main body unit that is integrally formed in a block shape and through which an oil passage is passed. Has been.

The variable throttle mechanism 210 is provided in the middle of an oil passage that conveys hydraulic oil from the pump 120 side (A side in the figure) to the operation control valve 300 side (B side in the figure).
As shown in FIG. 5, the variable throttle mechanism 210 has a variable throttle valve having a movable valve body 211 that can change the flow path cross-sectional area, and the position of the valve body 211 has a predetermined flow path cross-sectional area. A lock mechanism 212 that locks at a plurality of predetermined positions is provided.
For example, the valve body 211 can change the cross-sectional area of the flow path according to the required amount of oil determined for each type of in-vehicle hydraulic equipment in which the flow control device 200 is provided.
The lock mechanism 212 can lock the valve body 211 at a position corresponding to the required oil amount of a plurality of types of hydraulic equipment.
The lock mechanism 212 is provided with a lock key 213, and the lock mechanism 212 can be operated only when the lock key 213 is inserted.
Further, the variable throttle mechanism 210 can substantially block the oil passage by the valve body 211 and can stop the supply of the hydraulic oil to the operation control valve 300. Such a closing operation may be performed by manual operation of the lock key 130, but may be automatically performed by an actuator when a maintenance switch (not shown) is operated, for example.

The flow control valve 220 is provided in an oil passage that branches from the upstream side (A side) of the variable throttle mechanism 210 in the main oil passage from the A side to the B side to the hydraulic oil tank 110 side (T side).
The flow control valve 220 is a relief valve that bleeds off the hydraulic oil when the pressure in the main oil passage on the upstream side of the variable throttle mechanism 210 exceeds a predetermined value.
The flow control valve 220 bleeds hydraulic oil from the A side to the T side when the pressure on the A side is larger than the sum of the differential pressure between the A side and the B side and the spring force. As a result, only the amount of oil corresponding to the throttle flows through the variable throttle mechanism 210.

The downstream pressure control valve 230 is provided in an oil passage that branches from the downstream side (B side) of the variable throttle mechanism 210 to the outlet side (T side) of the flow control valve 220.
On the upstream side of the downstream pressure control valve 230 in this oil passage, a throttle 240 having a fixed flow passage sectional area is provided.
The downstream pressure control valve 230 is a relief valve that bleeds hydraulic oil to the tank side when the pressure on the downstream side (X side) of the throttle 240 becomes a predetermined value or more.
The downstream pressure control valve 240 bleeds hydraulic oil from the B side to the T side when the B side pressure is larger than the sum of the differential pressure between the B side and the X side and the spring force.

The operation control valve 300 supplies hydraulic oil supplied from the pump 120 via the flow control device 200 and the accumulator 140 to the cylinders C1 to C6 via the hydraulic line L.
FIG. 6 is a diagram showing the configuration of the operation control valve 300.
The operation control valve 300 includes solenoid valves SV1 to SV5 that are three-position direction control valves.
Each solenoid valve SV1 to SV5 switches the presence / absence and direction of hydraulic pressure supplied to each cylinder C1 to C6 in accordance with drive power supplied from a control device (not shown).

The solenoid valve SV1 supplies hydraulic pressure to the backflow prevention cylinder C1.
The solenoid valve SV2 supplies hydraulic pressure to the lift cylinder C2 and the automatic lock cylinder C3.
The solenoid valve SV3 supplies hydraulic pressure to the vertical movement cylinder C4.
The solenoid valve SV4 supplies hydraulic pressure to the cylinder C5.
The solenoid valve SV5 supplies hydraulic pressure to the discharge cylinder C6.
The oil passages for supplying hydraulic pressure from the solenoid valves SV1, SV2, SV4, SV5 to each cylinder include a relief valve that bleeds the hydraulic oil to the hydraulic oil tank 110 when the pressure exceeds a predetermined value. Is provided.

FIG. 7 is a graph showing the correlation between the inlet side (A side) flow rate and the outlet side (B side) flow rate in the flow rate control apparatus 200 of the example.
As shown in FIG. 7, in this embodiment, the input side flow rate and the output side flow rate are substantially equal up to a predetermined flow rate, but when the input side flow rate exceeds the predetermined flow rate, the increase in the input side flow rate is increased. The increase rate of the outlet flow rate is negligible, and the outlet flow rate (the amount of oil supplied to the operation control valve 300) is kept substantially constant.

According to the present embodiment described above, the following effects can be obtained.
(1) The variable throttle mechanism 210 can arbitrarily change the amount of oil supplied to the operation control valve 300, and there is no need to prepare a different flow control device 200 for each method of the dust collecting device 1. The common specification flow control device 200 can support a plurality of types.
For example, in the case of a garbage truck, it is possible to deal with both a press type and a rotary type by using a common device.
(2) By providing the downstream pressure control valve 230, even when a pressure exceeding a predetermined level is generated due to a failure of the control device of the valve or the electric motor 130, the pressure can be converted into a safe pressure or oil amount.
(3) Since the variable throttle mechanism 210 can shut off the oil passage, for example, the amount of oil at the time of maintenance can be reduced to zero, so that the operation of each actuator is prevented and the maintenance is safely performed. be able to.
(4) Since the variable throttle mechanism 210 includes the lock mechanism 212, it is possible to prevent the user from operating the variable throttle mechanism 210 to increase the oil amount in order to speed up the work operation.
(5) Even if it is an electric garbage collection vehicle which employs an electric motor 130 that requires a large mounting space as a drive source of the pump 120, the size of the entire system can be made compact.

(Modification)
The present invention is not limited to the embodiments described above, and various modifications and changes are possible, and these are also within the technical scope of the present invention.
For example, the working vehicle hydraulic device according to the embodiment is provided in, for example, a garbage truck, but can also be applied to a working vehicle equipped with other in-vehicle devices driven by hydraulic pressure.
The configuration of the dust collecting device is not limited to the panel type described above, and may be a rotating plate type.
In the embodiment, the pump is driven by an electric motor. However, the present invention is not limited to this. For example, the pump may be driven by an engine via a PTO mechanism.
Further, the electric motor and the PTO mechanism may be connected to a common pump, and the pump may be driven by both the electric motor and the engine. For example, the drive shaft of the pump, the electric motor, and the output shaft of the PTO mechanism may be arranged coaxially, and these may be connected in any order.
For example, it is good also as a structure which connects a PTO mechanism to the edge part on the opposite side to the pump 120 of the electric motor 130 of FIG. 3 in an Example.

DESCRIPTION OF SYMBOLS 1 Dust collection apparatus 10 Body 20 Tailgate hopper 21 Loading panel C1 Backflow prevention cylinder C2 Lift cylinder C3 Automatic lock cylinder C4 Vertical movement cylinder C5 Oyster cylinder C6 Discharge cylinder 100 Hydraulic circuit 110 Hydraulic oil tank 120 Pump 130 Electric motor 131 Battery 132 Inverter 140 Accumulator 150 Filter 200 Flow Control Device 210 Variable Throttle Mechanism 211 Valve Body 212 Lock Mechanism 213 Lock Key 220 Flow Control Valve 230 Downstream Pressure Control Valve 240 Throttle 300 Operation Control Valve SV1 to SV5 Solenoid Valve L Hydraulic Line

Claims (5)

A working vehicle hydraulic device including a hydraulic pump that supplies hydraulic oil to an operation control valve that controls the hydraulic pressure of a hydraulic actuator,
A flow rate control valve that is provided in an oil passage for supplying the hydraulic oil from the hydraulic pump to the operation control valve and bleeds off a flow rate equal to or higher than a predetermined flow rate;
A work vehicle hydraulic device, comprising: a variable throttle mechanism that is provided downstream of the flow control valve in the oil passage and is capable of adjusting an oil amount. 2. The work vehicle hydraulic device according to claim 1, further comprising a relief valve provided between the variable throttle mechanism and the operation control valve in the oil passage and capable of controlling a pressure. 3. The hydraulic device for a work vehicle according to claim 1, wherein the variable throttle mechanism is capable of blocking the oil passage. The hydraulic apparatus for a work vehicle according to any one of claims 1 to 3, wherein the variable throttle mechanism includes a lock mechanism that can be held at a predetermined throttle amount. The hydraulic pump drives an electric motor by controlling an inverter using a battery as a power source, and drives using the rotational force of the electric motor. Item 4. Hydraulic device for work vehicle according to item.

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