JPS6144511A - Weight balance controller - Google Patents

Abstract

PURPOSE:To balance weight without causing a shock, through a weight balance controller for a machine tool or the like, by detecting the kind of a replacing article, and operating a pressure regulator on the basis of a kind signal to control oil pressure to correspond to the kind. CONSTITUTION:When a workpiece in a balance weight state is replaced with a heavier workpiece W2, the kind of the workpiece W2 is detected by a limit switch 32 engaged with a dog 36, so that a kind signal is applied to a pressure regulator 38 through a sequence control circuit 30. A predetermined voltage corresponding to the kind of the workpiece W2 is sent out from the pressure regulator 38 to an oil pressure switch 46. As a result, a pressure reduction valve 50 is operated to alter oil pressure which is applied to a table 62 through a hydraulic pump 56 and a hydraulic cylinder 58 to oppose the weight of the workpiece W2. The balance of weight after workpiece replacement or the like is thus achieved quickly without causing a shock.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a weight balance control device, and more specifically, in a machine tool, preferably a machining center, when a spindle head, a tool, or a workpiece is selectively held via a cylinder, Pressure fluid corresponding to the weight change caused by replacing the head etc. is instantly supplied to the cylinder to prevent the generation of overload in the cylinder due to the replacement action and quickly ensure a new weight balance. The present invention relates to a weight balance control device configured to do so.

Machine tools, such as portal type machining centers, have traditionally had a hydraulic cylinder installed at the top of the column, and a rod extending from the hydraulic cylinder suspends and holds the spindle head, workpiece, tools, or a table with a pallet attached. configuration has been adopted. In this case, the weight of the table itself and the weight of tools, workpieces, etc. mounted on the table are added to the hydraulic cylinder, and the weight is balanced.

Figure 1 shows a complex machining center with such a configuration. In the workpiece machine tool 2A of this machining center 2, a guide member 6.6 is disposed on the upper part of the base 4, and a column 8 is displaceably mounted on the guide member 6.6. That is, the column 8 is connected to the guide member 6.6.
A ball screw 12 whose upper part rotates under the driving action of a motor 10.
can be displaced on the guide member in the direction of arrow A. A hydraulic cylinder 14 is mounted on the top of the column 8, and a motor 16 is mounted adjacent to the hydraulic cylinder 14.
is installed. The rotating shaft (not shown) of the motor 16 is
In this case, it is coupled and connected to the ball screw 18.

The hydraulic cylinder 14 suspends and holds the table 20 by its cylinder rod (not shown), while the ball screw 18 is capable of displacing the table 20 in the direction of arrow B under the rotational drive of the motor 16.

A valent 22 is detachably mounted on the table 20, and a workpiece 24 is further mounted on the pallet 22.

On the other hand, a spindle 26 having a cutting tool 28 attached to its tip is attached to the front side of the workpiece machine tool 2A in the figure, and the spindle 26 is held movably in the vertical direction (indicated by an arrow). A tool machine tool 2B is provided. The tool machine tool 2B includes a column 29, and this column 29 moves forward and backward in the direction of the arrow. Therefore,
By displacing the spindle 26 in the direction of the arrow and adjusting its height to face the workpiece 24 and causing the machine tools 2A and 2B to work together, the tool 28 will perform a predetermined cutting operation on the workpiece 24.

Therefore, in such a configuration, the hydraulic cylinder 14
The weight of the table 20, the pallet 22 and the workpiece 24 attached to the table 20 is added to the table 20, and a balance is maintained between the oil pressure in the cylinder 14 and the weight of the table 20, etc., and the ball screw 18 is The position of the table 20 is established under the action of rotation.

However, as is well known, this type of machining center 2 is required to cut various workpieces. Therefore, it goes without saying that there are cases where the work itself or the work and the pallet holding it are replaced together.

However, the weight of all types of workpieces and pallets is not constant, and therefore, the weight suspended by the hydraulic cylinder 14 changes each time the workpiece or pallet is replaced. In other words, the total ff1ffi of the table, pallet, and workpiece suspended by the hydraulic cylinder 14 will change each time these are replaced, and especially if the weight increases suddenly at the time of replacement, the balance will be affected. This will cause a considerable impact to the hydraulic cylinder that is trying to remove the force. Eventually, this impact slightly disturbs the positioning of the table 20 relative to a new workpiece, etc., making it difficult to ensure accurate and quick positional adjustment of the table. Moreover, over time, the accuracy of the machining center itself is excessively impaired, which on the other hand is a contributing factor to shortening its service life. Also,
Of course, a similar phenomenon occurs when the weight changes due to changes in the attachment of various tools and attachments on the tool machine tool 2B side.

Therefore, as a result of intensive research and efforts, the present inventors have determined that the pressure oil supplied from the hydraulic pump to the cylinder installed at the top of the column constituting the workpiece machine tool 2A is at a predetermined pressure. When the weight of the workpiece, pallet, etc. to be replaced changes, the model is detected and pressure oil corresponding to the change in weight of the model is supplied from the proportional solenoid valve. If the structure is such that the hydraulic pressure is instantly supplied to the cylinder via a pressure reducing valve and the workpiece, etc. is held after the hydraulic pressure is set in this way, it is suitable between the hydraulic cylinder and the workpiece, etc. to be replaced. It has been found that a suitable weight balance can be quickly secured and the above-mentioned disadvantages can be eliminated.

Therefore, an object of the present invention is to supply pressure oil corresponding to the weight change to a hydraulic cylinder when a workpiece, pallet, etc. to be replaced causes a change in weight in a machine tool, etc. The object of the present invention is to provide a weight balance control device that can achieve a new weight balance without impact between the hydraulic cylinder and the hydraulic cylinder.

In order to achieve the above object, the present invention includes a model identification means for identifying the model of the target article to be replaced in advance when it is attached, and a model signal identified by the model identification means is converted into an analog signal and transmitted. a pressure regulator that receives the sent signal and generates a voltage or current signal corresponding to the signal; and a pressure regulator that receives the output signal from the pressure regulator via an amplifier to open the valve. a proportional electromagnetic pressure reducing valve that adjusts the pressure, a hydraulic cylinder that is connected to an output port of the pressure reducing valve and carries a target article, and a hydraulic pump that supplies a predetermined pressure oil to the pressure reducing valve. Features.

Next, preferred embodiments of the weight balance control device according to the present invention will be described in detail with reference to the accompanying drawings.

In FIG. 2, reference numeral 30 indicates a sequence control circuit, and on the input side of this sequence control circuit 30, a model identification device 34 including a limit switch 32 as described later.
The output side of is connected. The output side of the sequence control circuit 30 is in this case connected to a stepless pressure regulator 38 .

The pressure regulator 38 includes therein a multi-point setting device 40 and a switching circuit 42 connected thereto. Note that this pressure regulator 38, that is, the multi-point setting device 40 is equipped with a power supply circuit 44.
is connected.

Incidentally, the output side of the stepless pressure regulator 38 is connected to a hydraulic pressure switching device 46. The hydraulic switching device 46 essentially includes an amplifier 48 and a proportional electromagnetic relief pressure reducing valve 50 connected to its output side. The input port of this pressure reducing valve 50 is connected to the discharge side of a pump 56 that supplies pressure oil under a predetermined pressure from a tank 54 by a hydraulic motor 52, and the output port of the pressure reducing valve 50 is connected to one side of a balance hydraulic cylinder 58. is connected to the input port of Cylinder roller 0 of the hydraulic cylinder 58 is connected to a table 6 that holds an object to be controlled, such as a spindle head, a workpiece, or a tool.
2), while this table 62 is connected to the ball screw 6.
It is screwed together with 4. The ball screw 64 can be rotated by a motor 66.

Therefore, in the device of the present invention, a model identification device 34 is provided close to the table. The machine type identification device 34 substantially includes a plurality of limit switches 32, and the leaves of the limit switches 32 correspond to the dowels 36 of the work W1 or W2.
configured to engage with. In addition, in the figure, reference numeral 68 indicates a relief valve connected to the discharge side of the pump 56.

The weight balance control device according to the present invention is basically constructed as described above, and its operation and effects will be explained next.

First, the workpiece W1 held by the table 62 is replaced from a state where the balance is maintained between the hydraulic cylinder 58 and the table 62, and the workpiece W2 is replaced with a workpiece W2 that is heavier than the previous workpiece. do. In this case, the weight of the newly mounted controlled object, that is, the workpiece W2, is determined by the limit switch 3 that engages with the dowel 36 when the workpiece W2 is replaced on the table 62.
2, the model is detected, and this model detection signal is introduced into the sequence control circuit 30 and determined. That is,
The sequence control circuit 30 receives a digital output signal from the model identification device 34 and outputs an analog signal corresponding to the model.

That is, this output analog signal is a signal related to the weight of the newly mounted workpiece W2. After all, the sequence control circuit 30 can be essentially interpreted as an interface circuit. This sequence control circuit 30 transmits a coded signal related to the weight of the work W2 to be cut to a switching circuit 42.
to be sent to. The switching circuit 42 closes one of the contacts 42a to 42j based on the coded signal, and opens the switch 40a to 40j that constitutes the multi-point setter 40 corresponding to the contact. A predetermined voltage is taken in from one of the power supply circuits 44 through the power supply circuit 44 and sent to the amplifier 48.

The amplifier 48 generates an output corresponding to this voltage using a proportional electromagnetic IJ.
It is supplied to the pressure reducing valve 50 with IJ-F, and the opening degree of the pressure reducing valve is adjusted. As a result, the flow rate of pressure oil from the hydraulic pump 56 is controlled, and when the weight increases, a flow rate commensurate with the opening degree of the pressure reducing valve 50 is sent to the hydraulic cylinder 58, and a new workpiece W2 is replaced. You will have to wait.

Therefore, even if the workpiece is replaced with the workpiece W2, the excess weight will be sufficiently carried by the hydraulic cylinder 58 whose pressure has already increased, and therefore, there is a risk that an excessive load will be applied to the ball screw 64, for example. There is no such thing.

That is, the change in pressure due to the increase in the weight of the workpiece W2 is sufficiently supported by the hydraulic cylinder 58, and as a result, there is no possibility of any impact occurring due to replacement of the workpiece, etc., and a new IT balance can be quickly secured. be exposed.

According to the present invention, as described above, with the simple configuration, it is possible to sufficiently cope with the frequent replacement of tools, workpieces, or spindle heads in machining centers without considering changes in their weight. Therefore, it is possible to prevent the occurrence of impact due to an excessive load on the ball or hydraulic cylinder at the time of replacement, and to quickly obtain a new weight balance. Therefore, it is possible to obtain a machining center that allows accurate positioning and control over a long period of time.

Although the present invention has been described above with reference to a preferred embodiment, the present invention is not limited to this embodiment. For example, it is also possible to use a proximity switch in place of a limit switch for model identification. It goes without saying that various improvements and design changes can be made without departing from the gist of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a partially omitted perspective view of a machining center according to the prior art, and FIG. 2 is a block diagram of a weight balance control device according to the present invention. 30...Sequence control circuit 32...Limit switch

Claims (3)

[Claims] (1) a model identification means for identifying the model of the target article to be replaced in advance when it is attached; a means for converting the model signal identified by the model identification means into an analog signal and sending the analog signal; a pressure regulator that receives a signal and generates a voltage or current signal corresponding to the signal; a proportional electromagnetic pressure reducing valve that receives an output signal from the pressure regulator via an amplifier to adjust the valve opening; A weight balance control device comprising: a hydraulic cylinder connected to an output port of the pressure reducing valve to support a target article; and a hydraulic pump feeding predetermined pressure oil to the pressure reducing valve. (2) In the device according to claim 1, the pressure regulator includes a multi-point setting device connected to a power source and a switching device connected to the multi-point setting device and opened and closed by an analog signal from a signal sending means. A weight balance control device consisting of a circuit. (3) The weight balance control device according to claim 1, wherein the model identification means includes a limit switch or a proximity switch.