JPS6322032Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to a speed adjustment device that adjusts the feed speed when a table of a machine tool or the like is fed using hydraulic pressure.

[Conventional technology]

As shown in Fig. 6, the table feeding of general machine tools is performed by connecting oil passages b and c that communicate with both chambers bordering piston e of hydraulic cylinder a to a hydraulic source via an operating valve d (switching valve mechanism). The oil passage c connected to the liquid tank j and connected to one rod side is connected to a hydraulic circuit in which a reduction valve f and a throttle valve g, which are switched by the movement of the piston e, and a reduction valve h are interposed in parallel. Therefore, there is a system in which the workpiece is approached by rapid traverse, and when it approaches a predetermined distance, the workpiece is decelerated to be machined, and then returned after machining.

[Problems to be solved with the idea]

In the conventional feed circuit, in order to supply oil to one side of the cylinder, all the oil discharged from the other chamber is returned to the oil tank, so in order to supply the amount of oil necessary for rapid feed, a large hydraulic pump and oil tank are required. This required a large amount of energy, and the associated energy was required.

[Means to solve the problem]

In view of this, the present invention selectively connects both the second oil passage and the first oil passage to the hydraulic pressure source and the liquid tank using actuated valves, and connects the second oil passage to the liquid tank. There is an on-off valve that closes when connected to the hydraulic pressure source and opens when connected to a hydraulic pressure source, as well as a second valve.
A third oil passage is provided between the deceleration valve provided in the oil passage and the cylinder and connected to the liquid tank and the hydraulic pressure source in a phase opposite to the first oil passage by the operating valve; The oil passage is equipped with a throttle valve and a check valve,
As a result, the amount of oil required for rapid traverse is reduced by half by opening the on-off valve and causing the liquid from the second oil path to flow back to the first oil path, reducing the amount of oil sent from the hydraulic pressure source of the conventional circuit to 1/2.
The hydraulic pump motor and liquid tank have been miniaturized to save energy, and the on-off valve can be closed during processing feed to make full use of the thrust force.

[Effect]

By moving the operating valve 12 from the illustrated neutral (stop) position to the right, the first port 12a is connected to the hydraulic pump 14, which is the hydraulic pressure source, and the second port 12b is connected to the liquid tank 1.
5 and when the hydraulic pump 14 is driven in this maintained state, the hydraulic oil is sent to the first oil passage 11 and the second oil passage 13a through the first port 12a, and at the same time, the hydraulic oil is sent to the second oil passage 13a. The interposed on-off valve 16 is opened by moving it to the left using hydraulic pressure. Thus, the same pressure acts on the front and back surfaces of the piston 7b within the cylinder 7a. Also, within the cylinder 7a is a piston rod 8 which occupies about 1/2 of the cross-sectional area, and moves to the right while pushing the table 4 due to the biasing force due to the difference in pressure receiving areas on the front and back surfaces of the piston 7b. The hydraulic oil in the right chamber, which is discharged at this time and corresponds to about 1/2 of the stroke volume of the piston 7b, is discharged from the second chamber.
The oil is returned to the first oil passage 11 via the oil passage 13a. Therefore, the amount of oil sent from the hydraulic pump 14 only needs to be reduced accordingly. Note that at this time, a part of the hydraulic oil discharged from the cylinder 7a is transferred to the variable throttle 1.
8 and returns to the liquid tank 15 from the second port 12b, but the amount is not large.

When the table 4 approaches the forward end due to rapid forwarding, the inclined portion of the lower surface of the cam 10 comes into contact with the roller 9b of the deceleration valve 17 and pushes it down, and the valve body 9c descends to close the deceleration valve 17. Therefore, all of the discharged hydraulic oil is returned to the liquid tank 15 through the variable throttle valve 18 from the third oil passage 13b with the oil passage cut off. That is, the back pressure that was acting in the rod 8 side chamber of the cylinder 7a is removed, and the pressure difference between the front and back surfaces of the piston 7b becomes as large as before, so that the large thrust necessary for machining can be fully obtained, and the hydraulic oil is The discharge speed of the table 4 is regulated by the variable throttle valve 18, and the table 4 is fed slowly.

When the table 4 reaches the forward end due to slow feeding and processing is completed, the operating valve 12 is switched to the reverse phase, the first port 12a communicates with the liquid tank 15, and the second port 1
2b communicates with the hydraulic pump 14. Therefore, the hydraulic oil discharged from the hydraulic pump 14 is transferred to the third oil passage 13.
It is supplied to the chamber on the rod 8 side of the cylinder 7a through the check valve 19 of b, and is supplied to the first oil passage 11 and the second oil passage 1.
Since the first port 12a connected to 3a leads to the liquid tank and drops to atmospheric pressure, the on-off valve 16 moves to the right and closes the second oil passage 13a, and the hydraulic oil supplied to the chamber on the rod 8 side passes through the on-off valve. 16, the table 4 quickly returns to its initial position while preventing the liquid from flowing back into the liquid tank 15.

Further, the operation of the other embodiment shown in FIG. 5 is such that the forward speed of the table 4 can be reduced in three steps. That is, in this example, the side road 13 described earlier
By providing the second variable throttle valve 18b in series with the variable throttle valve 18a provided in the
When the operating valve 12 is moved to the right and switched to the starting position, the first port 12a is connected to the hydraulic pump 14, and the second port 12b is connected to the liquid tank 15, as in the previous embodiment. connected to. As a result, when the hydraulic pump 14 is driven, the on-off valve 16
Since the valve is opened by the hydraulic pressure from the second oil passage 13a, the hydraulic oil discharged as the piston 7b moves to the right passes through the second oil passage 13a and flows into the first oil passage 1.
1 and flows to the other end chamber, and the table 4 is fast-forwarded.

Next, when the valve body 9c is lowered to the second position by the cam 10, the second oil passage 13a is closed and the first oil passage 13a is closed.
It will be delayed. At this stage, the hydraulic oil is bypassed by the second variable throttle valve 18b through the passage 20, so the speed of the piston 7b is controlled by the only throttle of the first variable throttle valve 18a installed in the bypass passage 13b. will be determined. Also, table 4 advances further and cam 1
When the valve body 9c is pushed down to the third position, the passage 20 is also cut off, and the second variable throttle valve 18b flows in series with the first variable throttle valve 18a. In this embodiment, since the second variable throttle valve 18b is set smaller than the first variable throttle valve 18a, the feeding speed of the table 4 is substantially lower than that of the second variable throttle valve 18b.
The second retardation is determined by the path area of b and proceeds at a second slower speed. Since the return operation of the table 4 is the same as in the first embodiment, the explanation will be omitted.

〔Example〕

In Fig. 1, 1 is a precision boring machine, which is a machine tool, and a spindle 3 with a cutting tool on the top surface of the bed 2.
and table 4 are provided. A workpiece 6 is clamped to a jig 5 on the upper surface of the table 4.
Reference numeral 7 denotes a hydraulic feed cylinder supported by the bed 2, from which a piston rod 8 protrudes and is connected to the table 4 via a bracket 4a. Reference numeral 9 denotes a conventionally known reduction valve 17 and a hydraulic circuit attached thereto;
A valve body 9c equipped with a roller 9b is provided on the upper surface of the valve body a, and is pressed by a cam 10 attached to the side surface of the table 4 to move in and out to switch the internal oil passage.
The cam 10 is formed with an inclined surface 10' for smooth pressing at the tip of the lower surface. 9d is an adjustment knob for adjusting the slow feed speed, and 9e is a second adjustment knob used only in the second embodiment, which will be described later.

The hydraulic circuit 9 will be explained with reference to FIG. The feed hydraulic cylinder 7 has a cylinder 7a divided into two chambers by a piston 7b, and the piston is provided with a piston rod 8 extending outwardly through an end wall on one side of the cylinder. Piston 7b of cylinder 7a
One of the chambers formed on both sides of the piston rod 8 is connected to the first port 12a of the operating valve 12 through the first oil passage 11, and the other chamber on the piston rod 8 side is connected to the first port 12a through the second oil passage 13a. , second oil passage 13a
The third port branched from the second port 12b and connected to the second port 12b.
It has an oil passage 13b. Reference numeral 14 denotes a hydraulic pump as a hydraulic pressure source communicating with the operating valve 12, and 15 is a liquid tank for storing hydraulic oil, the inside of which is at atmospheric pressure.

The second oil passage 13a includes an on-off valve 16 for shutting off the second oil passage 13a from the first oil passage 11, and a deceleration valve 1.
7 are interposed in series. The on-off valve 16 is connected to a second oil passage 13a communicating with the chamber on the piston rod 8 side.
opens when the pressure of the hydraulic pump 14 is applied to the
It is set to close when it is removed. Furthermore, a variable throttle valve 18 with pressure and temperature compensation and a check valve 19 that only allows liquid flow toward the cylinder 7a are provided in parallel in the third oil passage 13b.

The operating valve 12 is a three-position solenoid valve, and has three operating positions, in which the table 4 is stopped, moved forward, or returned to its original position. That is, a start signal and a direction change and stop signal are applied to the operating valve 12.

Another example shown in FIG. 5 is Table 4
The forward speed of the can be reduced in three stages.

A first variable throttle valve 18a and a second variable throttle valve 18b are provided in series in the side third oil passage 13b of the hydraulic circuit of the first embodiment, and a deceleration valve 17 that can be switched to three stages is provided. Others are omitted.

[Effect of idea]

As described above, in this invention, when the table 4 is rapidly transported to the processing position, the hydraulic pump 14 is connected to the chambers on both sides of the piston 7b in the cylinder 7a, one through the on-off valve 16, and the other is connected to the chamber on both sides of the piston 7b in the cylinder 7a. Since the hydraulic oil discharged from the chamber is returned to the other chamber, the amount of oil from the hydraulic source required for rapid traverse is small.
Therefore, the desired rapid feed rate can be achieved with a relatively small hydraulic pump and a small liquid tank. Furthermore, when the table 4 reaches the processing position such as cutting, the deceleration valve 17 is closed, and the chamber on the piston rod 8 side of the cylinder 7a is connected to the liquid tank 15, and becomes atmospheric pressure, so that a large thrust can be fully obtained as in the conventional case. Furthermore, when the table 4 returns, the on-off valve 16 shuts off the second oil passage 13a from the first oil passage 11, so that the hydraulic oil supplied to the chamber on the piston rod 8 side via the check valve 19 has the same hydraulic pressure. Since it is supplied by a pump, it is possible to return the table 4 to a rapid return. In addition, the second
If the configuration is as in the embodiment, it is possible to achieve the effect of making multi-stage speed change possible.

[Brief explanation of the drawing]

The drawing shows an example of this invention.
FIG. 1 is a side view of the machine tool, FIG. 2 is a side view of its main parts, and FIG. 3 is a front view. FIG. 4 is a piping diagram showing the hydraulic system, FIG. 5 is a similar piping diagram showing another embodiment, and FIG. 6 is a conventional piping diagram. 7...Feed cylinder, 9...Speed control valve, 9c
... Valve body, 11 ... First oil passage, 12 ... Operating valve,
13a...Second oil passage, 16...Opening/closing valve.

Claims (1)

[Claims for Utility Model Registration] (1) The interior of the cylinder is divided into two chambers by the piston, with a second oil passage leading to one chamber on the piston rod side of the cylinder, and a first oil passage communicating with the chamber on the other side. The second oil passage is provided with a deceleration valve that is switched by the movement of the piston, and the second oil passage is connected to the cylinder and the deceleration valve. A third oil passage is provided that branches between the throttle valve and the cylinder, and a check valve that allows flow to the throttle valve and the cylinder is provided in parallel with the throttle valve, and the third oil passage is provided with a check valve that allows flow to the throttle valve and the cylinder. The oil passage is connected to the oil tank and the hydraulic source in the opposite phase, and the second oil passage has an opening/closing mechanism that opens when both the first and second oil passages are connected to the hydraulic source, and conversely closes when they are connected to the oil tank. A speed regulating device for a machine tool, etc., characterized in that a differential hydraulic circuit is constructed by interposing a valve. (2) The speed control device for a machine tool, etc., according to claim 1, wherein the throttle valve is a variable throttle valve that maintains a constant controlled flow rate regardless of fluctuations in pressure and temperature.