JPH01104599A - Cargo-handling controller - Google Patents

Abstract

PURPOSE: To eliminate the energy loss at the time of single operation by restraining the number of revolution of an oil pump motor with a cargo handling chopper at the time of single operation for reach and tilting, and on the other hand, supplying the operating oil to a reach and tilt cylinder at the time of the symultaneous operation through the only restricting circuit. CONSTITUTION: In a case of the single operation for operating the only reach cylinder 1, an oil pump P is rotated with 60-80% of duty ratio on the basis of the control of a cargo handling chopper. The reach cylinder 1 is thereby operated at the optimal speed. At this stage, the operating oil is directly supplied to a reach section pool A without passing through a restricting circuit 3. Continuously, at the time of the symultaneous operation of the reach cylinder with the lift cylinder, the operating oil passes the only restricting circuit 3 and supplied to the reach section pool A. Pressure of the operating oil is raised to the lift operating pressure or more by this restricting effect of the restricting circuit 3, and the operating oil is divided for flowing to both of the reach cylinder 1 and the lift cylinder 2 so as to operate both them at the same time.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a cargo handling control device for a forklift, and more specifically, energy saving during single reach or tilt operation, and simultaneous operation of lift raising operation and reach or tilt operation. The present invention relates to a cargo handling control device that can perform the following operations.

[Prior art]

In the reach type battery forklift, methods for controlling the reach speed include an electromagnetic contactor type as shown in FIG. 5 and a cargo handling chopper type as shown in FIG. 6.

The former electromagnetic contactor type is shown in Figure 5.

An oil pump P, a single operating oil tank T, a reach cylinder 1 that operates the fork and mast of a forklift in the front and rear directions, a reach section spool C that controls the operation of the reach cylinder 1, and a lift cylinder that raises and lowers the mast of the forklift. 2 and the lift cylinder 2
The lift section spool D controls the operation of the lift section spool D.

Both section spools C and D are disposed within the oil control valve O.

And the above oil pump 122 section spool C
, D and both cylinders 1.2 are connected by an operating oil circuit. Moreover, the reach section spool C has each section of a reach retraction C1, a non-operating C2, and a reach extrusion C3. The above-mentioned lift section spool D is used for lifting up 1. It has a non-actuating section D2 and a lift lowering section D3. In addition, the code|symbol 4 is a bypass passage which flows into reach section spool C.

When the reach cylinder 1 and lift cylinder 2 are operated by this device, the spools of the section spools C and D are respectively operated to supply or cut off the working oil from the oil pump P. The figure shows a state in which the reach cylinder 1 is activated and the lift cylinder 2 is inactivated.

However, in this electromagnetic contactor type device.

The reach speed is controlled in section CI of the reach section spool by returning excess working oil in excess of the amount of working oil required to obtain the optimum reach speed to the tank T through the return passage 54. This is because if the entire amount discharged from the oil pump P is sent to the reach cylinder 1, the reach speed will be too high.

On the other hand, when lifting the lift and operating the reach at the same time,
The reach relationship uses the CI section as described above, while the lift section spool D uses the DI section. At this time, the hydraulic oil does not flow to the return passage 54 of the reach section spool C, and the oil pressure is increased by the restriction provided in the passage on the return side from the reach cylinder in the CI section, and the lift cylinder 2 is activated with the reach operation. Lifting is also performed when the operating pressure is exceeded.

This method is used for simultaneous reach and lift operations.

The load can be increased according to the oil pressure.

Good for cargo handling.

Next, as shown in Fig. 6, the latter cargo handling chopper type uses reach section spool A in place of reach section spool C in the electromagnetic contactor type (Fig. 5), and oil pump P. The difference is that it is controlled by a cargo handling chopper.

As shown in the figure, the reach section spool A in this cargo handling chopper type is designed to cut off the oil return passage 54 when the reach cylinder 1 is activated. In addition, this section spool A has reach retraction Al and non-operating A.
2 and reach extrusion A3 sections. Other than that, the lift section spool B, etc. are the same as those of the electromagnetic contactor type.

However, in the case of the cargo handling chopper type, when operating the reach cylinder, the cargo handling chopper is set to a duty ratio of about 60 to 80% to keep the rotational speed of the oil pump P low to optimally control the reach speed. (Therefore, as mentioned above, sections AI and A3 of section spool A do not have any throttle or relief circuits.) When lift raising and reach operation are performed simultaneously, the operating pressure of lift cylinder 2 is equal to that of reach cylinder 1. Since the operating pressure is higher than that of the lift, the lift will not rise until reach operation is completed. This system is superior in that there is little energy loss because it uses a cargo handling chopper, and there is little rise in oil temperature because there is no restriction in the hydraulic circuit.

In addition, the above 5. Regarding FIG. 6, the reference numbers for each part not mentioned in the above explanation are shown in Section 1, which will be described later. The same part as that in FIG. 2 is shown.

[Problems to be solved]

As mentioned above, the electromagnetic contactor type allows simultaneous reach and lift operations, which is advantageous for cargo handling work. However, in this method, due to the throttling of sections C1 and C3 of the reach section spool C, the hydraulic pressure is increased more than necessary during reach operation alone, resulting in large energy loss.

On the other hand, with the cargo handling chopper type, the energy loss is small as mentioned above. However, since the required flow rate is sent to the reach cylinder, the pressure only rises to the hydraulic level required for its operation, and simultaneous reach and lift operations are not possible. It's impossible.

The above matters apply to counter-type battery forklifts. The same applies to tilt and lift operations.

In view of the above-mentioned problems, the present invention can save energy during single reach or tilt operation, and can simultaneously perform lift raising operation and reach or tilt operation. The present invention aims to provide a cargo handling control device for a forklift.

[Means for solving problems]

The present invention relates to a lift cylinder for lift operation.

An oil control valve having a reach cylinder for reach operation or a tilt cylinder for tilt operation, a lift section spool for controlling the operation of each of the cylinders, and a reach section spool or tilt section spool; and 2. Through the control valve. A cargo handling control device for a forklift, comprising: an oil pump for supplying working oil to each cylinder; and a working oil circuit connecting the oil pump, the control valve, and each cylinder. has a cargo handling chopper that controls the rotation of the cargo handling motor that drives the oil pump, and the reach section spool or tilt section spool has a working oil inlet side that allows working oil to pass through only during simultaneous lift and reach or tilt operations. When the reach or tilt is operated alone, the rotation speed of the oil pump motor is kept low by the cargo handling chopper.On the other hand, when the lift and reach or tilt are operated simultaneously, the operating oil is supplied to the reach cylinder or tilt cylinder only through the throttle circuit. A cargo handling control device for a forklift, characterized by supplying the following:

The most distinctive feature of the present invention is that the rotation of the cargo handling motor that drives the oil pump is controlled by a cargo handling chopper, and that a throttle is provided on the inlet side of the reach section spool or tilt section spool.

When operating the reach (hereinafter the same applies to tilt) alone, operating oil is supplied directly to the reach section spool without going through the throttle circuit, and the duty ratio of the cargo handling chopper control is set to a low value (for example, 60 to 8
On the other hand, when lift raising and reach operation are performed simultaneously, the operating oil is supplied to the reach section spool only through the throttle circuit, and the duty ratio of the cargo handling chopper control is set to 100%, or the cargo handling chopper control is Switch to another bypass electrical circuit and run the oil pump at or near maximum rpm.

Therefore, the duty ratio during the single reach operation is set in advance in the cargo handling chopper so that the optimum reach speed can be obtained. And when the section spool is moved during reach operation.

For example, the cargo handling chopper is activated by operating a limit switch or the like. As a result, the oil pump is operated in an optimum state for reach operation, that is, in a state without energy loss.

The above restriction is to allow the operating oil to pass only when both reach and lift are operated at the same time.1Normally it is a constant restriction, but if necessary, a variable type that can control the flow rate is used. You can also do that.

[Function] In the present invention, when only the reach cylinder is operated, the oil pump is rotated at a duty ratio of about 60 to 80% by cargo handling chopper control. This causes the reach cylinder to operate at the optimum speed. At this time, 1 working oil is.

It does not pass through the throttle circuit and is fed directly to the reach section spool as shown in FIG.

Thus, when the reach cylinder and lift cylinder are operated simultaneously, one working oil is supplied to the reach section spool only through the throttle circuit.

Then, due to the throttling effect of this throttle circuit, the pressure of the first working oil is increased above the lift working pressure, and the second working oil is divided into both the reach cylinder and the lift cylinder, making it possible to operate both the reach cylinder and the lift cylinder simultaneously. Also, at this time, the duty ratio of the cargo handling chopper is set to 100%, or the oil pump motor is directly driven instead of being controlled by the cargo handling chopper to rotate the oil pump to the maximum speed. As a result, the oil pump reaches its maximum output and the operating pressure of the 9 operating oil is increased.
The above simultaneous operations are performed.

〔effect〕

According to the present invention, a cargo handling chipper and a throttle circuit are provided, and the cargo handling chipper and throttle circuit are used as described above when the reach cylinder is operated alone or when this and the lift cylinder are operated simultaneously, so that the reach It is possible to provide a cargo handling control device that does not cause energy loss during operation (and can perform the above-mentioned simultaneous operations. Also, as described above).

The present invention can be applied not only to a reach-type battery forklift that performs a reach operation, but also to a counter-type battery forklift that performs a tilt operation.

〔Example〕

An embodiment in which the present invention is applied to a reach-type battery forklift will be described with reference to FIGS. 1 to 4.

Note that FIGS. 1, 3, and 4 show the state when the reach is operated alone, and FIG. 2 shows the state when the reach and lift are operated simultaneously.

As shown in FIG. 1, this example includes a reach cylinder 1, a reach section spool A for operating this, a lift cylinder 2 and a lift section spool B for operating this, and both cylinders 1.2. It consists of an oil pump P for supplying working oil via section spools A and B, and an oil tank T for storing working oil.

Further, the section spools A and B are disposed within the oil control valve 0.

The above reach section spool A has a reach pull-in,
It has sections Al, A2 and A3 of non-actuation and reach extrusion. The section spool A also has an inlet passage 51 and a check valve 59 branched from the passage 51 on its inlet side, an operating passage 52. and an outlet passage 53 connected to the oil tank T. The operating passage 52 also includes a bypass passage 5 which does not pass through the lift section spool B in front of the check valve 59.
0 is connected, and a throttle 3 is interposed in the bypass passage 50. Further, the feed passage 51 is connected to a feed passage 64 of a lift section spool B, which will be described later. Further, the outlet side of the reach section spool A is connected to a return passage 54.
Reach extrusion side passage 55. It has a reach pull-in stool passage 56. The return passage 54 merges with the outlet passage 53.

In addition, the lift section spool B includes sections Bl for lifting the lift, inactivating the lift, and lowering the lift.

It has B2 and B3. The section spool B has an inlet passage 61. connected to the oil pump P on its population side.
An operating passage 62 having a check valve 69 branched from the inlet passage 61. Outlet passage 63 connected to oil tank T
has. Further, on the exit side of the section spool B, there is a delivery passage 64 connected to the delivery passage 51 of the section spool A, a reserve passage 65, and a lift lifting passage 66.
has. Note that a bypass passage 4 is provided between the feed passage 61 and the oil tank T. Further, reference numeral 68 is a working oil return passage.

Next, the oil pump P is operated as shown in FIG.

It is rotated by motor M. The rotation of the motor M is controlled by a cargo handling chopper circuit 7. The cargo handling chopper 7 is powered by a battery 70. A DC-DC converter 71 that supplies a drive signal to the switching element 73. It consists of a switching element 72 that controls the drive signal of the converter 71, and a limit switch SA that detects the operation of the reach section spool.

Further, in the figure, reference numeral SB indicates a limit switch that detects the operation of the lift section spool B, and reference symbol F indicates an oil filter.

The limit switch SA is provided near the reach section spool A, as shown in FIG.

It is turned on and off depending on the state of contact with the tip 83 of the operating lever 84 that operates the section spool A. The operating lever 84 is pivotally supported by a pin 841 on a bracket 861, and above the operating lever 84 are operating elements 85. Tip 8 on the left
It has 3. The tip 83 has end surfaces 831, 832 and 8 that come into contact with the roller-shaped detection end 87 of the limit switch SA.
It has 34. The end faces 831, 832 and 834 are configured to abut the detection end 87 when the sections AI, A2 and A3 of the section spool A are in a position where they open to the passages 51-53, 54-56. .

In the figure, 80 is a lead wire of limit switch SA, 82 is an arm connecting lever 84 and the spool end 81 of section spool A, 821 is a pivot pin between lever 84 and arm 82, and 86 is lever 84 A spring 89 is provided between the bracket 861 and the vehicle body.

Further, a limit switch SB (FIG. 3) for detecting the operation of the lift section spool B is also provided in the same manner as described above.

Next, the effects of the two devices will be described.

First, when operating the reach alone, when retracting the reach,
As shown in FIG. 1, the reach section spool A opens its section AI to the feed passage 51 or the like. Further, the lift section spool B is located in the non-operating section B2, as shown in the figure. As shown by the arrow in the working oil circuit in the same figure, the working oil for operating the reach cylinder 1 is supplied by the oil pump P to the feed passage 61. Cefsilane B2 in lift section spool B. It is sent to section A1 of the reach section spool A via the feed passage 51.

Here, 1 working oil is 1 reach cylinder working, so
A branch passage 52 from the feed passage 51. Check valve 59. Section AI, through the retraction side passage 56, the reach cylinder l
is fed into the lead-in side of the At this time, 1 operating oil is 3
Although the flow attempts to flow through the bypass passage 50 provided with
Because of this, there was almost no flow, and the reach cylinder 1 was removed using the above route.
sent to. At this time, the entire amount of the operating oil 9 is sent to the reach cylinder 1, and the excess operating oil is not returned to the reach circuit as in the electromagnetic contact type conventional technology (Fig. 5). The working oil on the extrusion side of the cylinder 1 is supplied to the extrusion side passage 55. Cefushiran At,
Exit passage 53. It returns to the oil tank T via the return passage 68.

In the above, the motor M of the oil pump P is.

As shown in FIG. 3, the cargo handling chopper circuit 7 allows
The rotation is controlled at a duty ratio of about 60 to 80%. That is, when the reach section spool A is operated to the section A1 position as described above, the tip 831 of the lever 84 is moved to the limit switch S as shown in FIG.
Turn A on.

As a result, the cargo handling chopper circuit is turned on as shown in FIG. At this time, the limit switch SB of the lift section spool B is in an off state. Then, the power of the battery 70 is applied, and an on/off signal (chopper signal) from the switching element 72 is output to the base terminal of the transistor of the switching element 73, and the former switching element 73 is controlled on/off.
The rotation of motor M is chopper controlled.

As mentioned above, when operating reach alone, oil pump P
The rotation is controlled by a cargo handling chopper with a duty ratio of about 60 to 80%. Note that the above duty is set so that the reach cylinder can be operated at an optimal speed. Also 1
When pushing out the reach cylinder 1, the same operation as above is performed with the section spool A in a state where the section A3 is open.

Therefore, according to this example, when the reach operation is performed alone, the reach operation can be performed while the rotation of the motor M of the oil pump P is reduced below the maximum speed, and there is no energy loss.

Next, when operating reach and lift at the same time.

The operating oil circuit is as shown in Figure 2. The circuit is
Lift section spool B is in a state where section B1 is open for lifting. This section B1 is the reach section spool A.
The flow of working oil to the passageway 51 is blocked. Other details are the same as those in FIG. 1 (reach only operation state). During this simultaneous operation, one working oil flows as shown by the arrow in the figure.

What should be noted here is that the passage passage 51 and the passage passage 61 of the reach section spool are blocked by the section Bl of the lift section spool B, and the working oil supply to the reach cylinder 1 is restricted to the restriction 3.
This means that it can only be done through. Also, during this simultaneous operation.

In FIG. 3, the limit switch SB is turned on, the oil pump motor M rotates at maximum speed without being controlled by the cargo handling chopper, and the oil pump P operates at the maximum discharge amount toward reach cylinder 1 and lift cylinder 2. Oil is pumped out.

Therefore, according to this example, the oil pump P is rotated at maximum speed during reach and lift operations at the same time.

Furthermore, since the operating oil is supplied to the reach cylinder 1 only through the throttle 3 provided in the bypass passage 50, the throttle effect of this throttle 3 causes the lift cylinder 2 to
The high-pressure operating oil required for the lift can be simultaneously supplied to both, allowing both to operate smoothly at the same time.

In the above, the rotation of the oil pump motor M during simultaneous operation is controlled by the connection of the limit switch SB which is connected in parallel with the cargo handling chopper.

Although the rotation is set to the maximum, a circuit for chopper control with a duty ratio of nearly 100% may be provided and this circuit may be linked to the limit switch SB. At this time, the limit switch SA shown in FIG. 3 is configured to be turned off.

In addition, when operating the lift 2 independently, the lift section spool B is in the state of the section Bl as described above.
The reach section spool A is in the state of section A2, and the oil pump motor is rotated at or near the maximum rotation.

[Brief explanation of the drawing]

1 to 4 show embodiments of the present invention. Figure 1 shows the operating oil circuit state during reach operation alone. Figure 2 shows the state of the circuit when reach and lift operations are performed simultaneously. Fig. 3 is an electric circuit diagram for cargo handling chopper control, Fig. 4 is a diagram showing the limit switch installed on the reach control valve, Figs. 5 and 6 show the conventional technology, and Fig. 5 is an electromagnetic contactor type, FIG. 6 shows each operating oil circuit diagram of the cargo handling chopper type. 1. Reach cylinder. 2...Lift cylinder. 3. ・・Aperture. 4...Bypass passage. 50... Bypass passage. 7... Cargo handling chopper circuit. A, C...Reach section spool. B, D...lift section spool. O, 0, oil control valve. P...Oil pump. T...Oil tank. SA, SB...Limit switch.

Claims (4)

[Claims] (1) It has a lift cylinder for lift operation, a reach cylinder for reach operation or a tilt cylinder for tilt operation, a lift section spool for controlling the operation of each cylinder, and a reach section spool or a tilt section spool. A forklift truck having an oil control valve, an oil pump for supplying working oil to each cylinder via the control valve, and a working oil circuit connecting the oil pump, the control valve, and each cylinder. In the cargo handling control device, the oil pump has a cargo handling chopper that controls the rotation of a cargo handling motor that drives the oil pump, and the reach section spool or tilt section spool has a lift and a lift on the operating oil inlet side. It has a throttle circuit that allows the operating oil to pass only when reach or tilt is operated simultaneously, and when reach or tilt is operated alone, the rotation speed of the oil pump motor is kept low by the loading chopper, while when lift and reach or tilt are operated simultaneously, the throttle circuit A cargo handling control device for a forklift, characterized in that operating oil is supplied to a reach cylinder or a tilt cylinder only through a circuit. (2) The cargo handling control device according to claim 1, wherein the duty ratio of the cargo handling chopper during reach or tilt operation alone is kept low to about 60 to 80%. (3) The cargo handling control device according to claim 1, wherein the oil pump motor is driven at a maximum rotational speed during simultaneous lift and reach or tilt operations. (4) The cargo handling control device according to claim 1, wherein the cargo handling chopper control is operated by a limit switch linked to each cargo handling lever for lift, reach, or tilt.