JP3993933B2 - Machine tool tool changer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for automatically changing a tool such as a cutting tool for a machine tool.
[0002]
[Prior art]
The conventional apparatus shown in FIG. 4 includes an auto tool changer A and a clamp mechanism R.
The auto tool changer A selects a target tool and conveys it to the clamp mechanism R, and has a plurality of hydraulic actuators (not shown) as main elements. The clamp mechanism R is mainly composed of the cylinder 1 and the electromagnetic valve 2. The auto tool changer A and the clamp mechanism R are connected in parallel to the hydraulic pump P. The hydraulic pump P is driven by the rotational force of the electric motor M and discharges hydraulic oil from the tank T. Suck up and discharge.
The clamp mechanism R uses the thrust of the cylinder 1 to maintain or release a clamp force of a clamp (not shown). The solenoid valve 2 for controlling the cylinder 1 is connected to a controller C composed of a CPU or the like. The controller C is also connected to limit switches 3 and 4 for detecting the position of the cylinder 1.
[0003]
When the electromagnetic valve 2 is held in the illustrated normal position in the apparatus as described above, the pump P communicates with the rod side chamber 1a of the cylinder 1 and the piston side chamber 1b communicates with the tank T. Therefore, the piston rod 5 of the cylinder 1 is pushed up. In this pushed-up state, the clamp force is maintained by the spring force applied to the clamp (not shown).
Further, when the solenoid valve 2 is switched from the illustrated normal position based on a signal from the controller C, the piston side chamber 1b is in communication with the hydraulic pump P and the rod side chamber 1a is in communication with the tank T.
Therefore, the piston rod 5 of the cylinder 1 moves downward against the spring force, and the clamping force is released by the force. The position at which the clamping force is released is detected by the limit switch 3, and the detection signal is sent to the controller C.
[0004]
Upon receiving the signal from the limit switch 3, the controller C outputs a signal for returning the solenoid valve 2 to the normal position after receiving a signal indicating that a tool such as a cutting tool has been replaced or after a set time has elapsed. To do. If the solenoid valve 2 is returned to the normal position in this manner, the cylinder 1 is kept in the pushed-up state and a clamping force is exerted by the action of the spring force. In such a clamp state, a signal to that effect is transmitted to the controller C, and the electric motor M is also stopped.
As described above, the clamping force of the clamping mechanism R is exhibited or released, and a tool such as a cutting tool is attached or detached.
[0005]
[Problems to be solved by the invention]
In the conventional apparatus as described above, the hydraulic pump P, the auto tool changer A, and the clamp mechanism R must be connected by the pipe 6. There was a problem that there were many restrictions. Moreover, although leakage from the connecting portion of the pipe 6 increases, this oil leakage has been regarded as the biggest drawback when hydraulic pressure is used in a machine tool.
The auto tool changer A and the clamp mechanism R have different characteristics. For example, the auto tool changer A requires a speed rather than a force, and the clamp mechanism R requires a large force and an instantaneous speed. When those having different characteristics are driven by a single hydraulic pump P, this hydraulic pump P must have the function of the greatest common divisor required for both the autochanger A and the clamp mechanism R. Thus, when the function of the greatest common divisor is calculated | required, not only must the hydraulic pump P be enlarged, but it must be operated continuously. The increase in size of the hydraulic pump has been a factor in increasing the cost of the entire apparatus.
[0006]
Furthermore, the hydraulic pump must supply pressure oil to both the auto tool changer A and the clamp mechanism R, but the electric motor continues to rotate in order to prevent the start-up delay of both of them. The hydraulic pump P must always be kept in a standby state. If the hydraulic pump P continues to rotate in this way, there is a problem that energy loss increases as a matter of course.
An object of the present invention is to provide an apparatus that eliminates the need for piping and that can control the clamping mechanism individually, and that does not cause a delay in starting the electric motor while rotating the hydraulic pump only when necessary. is there.
[0007]
[Means for Solving the Problems]
The present invention includes a clamp mechanism that clamps a tool such as a cutting tool of a machine tool, and an auto tool changer that selects a target tool and conveys it to the clamp mechanism, and a spring force of a spring is applied to a rod provided in the clamp mechanism. The clamp force is maintained by the action of the spring force, while the cylinder thrust is applied to the rod against the spring force, and the clamping force of the clamp mechanism is released by the rod thrust against the spring force. It is assumed that the machine tool replacement device is used.
The first invention is based on the above device, and the cylinder is provided with a pair of passages, and a port is directly connected to the pair of passages to fix the control valve. The control valve includes a hydraulic pump and an electric motor for driving the hydraulic pump, while mounting the tank integrally, on SL electric motor, a structure in which only drives to release the clamping force of the clamping mechanism, and the drive timing and automatic of the electric motor A controller for controlling the work procedure of the tool changer is provided, and this controller controls the electric motor according to a specific reference operation of the auto tool changer before the clamping force of the clamp mechanism is released or an opening / closing operation of the door of the auto tool changer. It is characterized in that it is activated .
[0008]
The second invention is characterized in that a movement amount detection mechanism is provided in the cylinder, and the movement position detection mechanism detects the movement position of the cylinder to control the control valve and the hydraulic pump.
The third invention is characterized in that the movement amount detection mechanism is a limit switch.
The fourth invention is characterized in that the movement amount detection mechanism is a pressure switch.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
In the first embodiment shown in FIGS. 1 and 2, the auto tool changer A and the clamp mechanism R are separated, and the auto tool changer A is driven by an electric motor (not shown).
The clamp mechanism R is provided with a rod 11 on the main body 10 shown in FIG. 1, and this rod 11 is not shown provided at the tip of the rod 11 when the rod 11 is in the illustrated push-up position by the spring force of the spring 12. The clamp clamps a tool such as a tool by the spring force of the spring 12. When the rod 11 is pushed down against the spring 12, the clamping force is released. A mechanism for exerting a clamping force with the thrust of the rod 11 and releasing the clamping force is well known in the art.
[0010]
A cylinder 13 is fixed on the main body 10 as described above. A piston 14 is slidably incorporated in the cylinder 13, and the inside of the cylinder 13 is divided into a lower chamber 13a and an upper chamber 13b. Further, the piston rod 15 of the piston 14 protrudes from both the upper and lower sides of the cylinder 13 and the lower rod portion 15a is opposed to the rod 11 of the clamp. Accordingly, when the piston 14 moves downward in FIG. 1, the lower rod portion 15a pushes down the rod 11 against the spring 12 and releases the clamping force of a clamp (not shown).
[0011]
Further, an indicator rod 16 is raised at the protruding end of the upper rod portion 15 b of the piston rod 15, and a switching rod 17 is fixed to the indicator rod 16. And this switching rod 17 is made to face between a pair of limit switches 18 and 19 arrange | positioned up and down.
Therefore, if the piston 14 is stroked by the interval between the limit switches 18 and 19, one of the limit switches 18 or 19 is turned on. Moreover, since the limit switches 18 and 19 are connected to the controller C as shown in FIG. 2, the on / off signals of the limit switches 18 and 19 are input to the controller C.
The limit switches 18 and 19 constitute the movement amount detection mechanism of the present invention.
[0012]
A valve body 20 of a control valve v composed of an electromagnetic valve is fixed to one side of the cylinder 13. A hydraulic pump P and a tank T are fixed to one side of the valve body 20, and an electric motor M is fixed to the other side. The control valve v and the electric motor M are connected to the controller C. The electric motor M thus configured keeps the stopped state unless a drive signal from the controller C is input. Therefore, as a matter of course, the hydraulic pump P also remains stopped. The reason why the hydraulic pump P is driven after receiving the signal from the controller C in this way is to drive the hydraulic pump P only when necessary to reduce its energy loss.
[0013]
The controller C of this embodiment is composed of a CPU and the like, and also controls the auto tool changer A as in the prior art. However, this controller is configured to drive the electric motor M on the basis of a reference operation in the work procedure of the auto tool changer A, for example, an operation before the clamp is operated such as opening its door. The reason why the electric motor M is driven in accordance with the reference operation of the auto tool changer A is to prevent the start-up delay of the electric motor M. In other words, the electric motor M does not immediately reach the desired number of revolutions when starting up. This start-up delay of the electric motor eventually becomes an operation delay of the cylinder 13 and becomes an obstacle to speeding up the work. However, if the electric motor M is driven in accordance with the reference operation of the auto tool changer A before the operation of the clamping mechanism R as described above, even if there is a start-up delay of the electric motor M, the clamping mechanism R is affected. Does not affect.
Further, one port of the control valve v communicates with the lower chamber 13 a through a passage 21 formed in the cylinder 13, and the other port communicates with the upper chamber 13 b through a passage 22.
[0014]
FIG. 2 shows the configuration of the clamp mechanism R as a circuit. As apparent from FIG. 2, when the control valve v is in the illustrated normal position, the hydraulic pump P communicates with the lower chamber 13 a of the cylinder 13 via the passage 21, and the upper chamber 13 b passes through the passage 22. It communicates with the tank T.
When the control valve v is switched from the normal position, the lower chamber 13a communicates with the tank T and the upper chamber 13b communicates with the hydraulic pump P.
In the figure, reference numeral 23 denotes a relief valve.
[0015]
Next, the operation of the first embodiment will be described.
When the clamp mechanism clamps a tool such as a cutting tool (not shown), the control valve v maintains the normal position shown. If the control valve v maintains the normal position, the piston 14 keeps the pushed-up position as described above, and the rod 11 also keeps the pushed-up position by the action of the spring 12. If the rod 11 remains in the pushed-up position as described above, the clamp continues to clamp the tool. At this time, the electric motor M is kept stopped.
[0016]
From the above state, the controller C outputs a specific operation signal of the auto tool changer A before the operation of the clamp mechanism R, and also outputs an activation signal of the electric motor M. Based on the start signal of the electric motor M, the electric motor M is rotated in advance. Thus, if the electric motor M is rotated in advance, when the clamp mechanism R is operated, the number of rotations is increased to an intended value.
Thereafter, if the control valve v is switched from the normal position, the lower chamber 13a of the cylinder 13 communicates with the tank T and the upper chamber 13b communicates with the pump P, so that the piston 14 descends. When the piston 14 is lowered, the rod 11 of the clamp is pushed down by the lower rod portion 15a.
When the rod 11 is lowered to a predetermined position, the clamping force of the clamp is released. The position of the rod 11 when the clamping force is released is a position where the switching rod 17 turns on the lower limit switch 19.
[0017]
When the limit switch 19 is turned on in this way, the control valve v is kept at the switching position within the set time even if the controller C operates to stop the electric motor M / hydraulic pump P. When this set time elapses or a tool replacement end signal is input, the controller C transmits a switching signal to the control valve v, and switches the control valve v to the normal position again.
As described above, when the control valve v is switched to the normal position, the piston 14 rises and causes the clamp to exert the clamping force again.
At this time, the switching rod 17 contacts the upper limit switch 18 and turns it on. When the limit switch 18 is turned on in this way, the controller C operates to stop the electric motor M. If the electric motor M stops, the hydraulic pump P also stops. However, at this time, since the rod 11 is kept in the pushed-up position by the spring force of the spring 12, the clamping force is maintained by the spring force of the spring 12.
[0018]
According to the first embodiment, the control valve v, the hydraulic pump P, the tank T, and the electric motor M are integrated and fixed to the cylinder 13, so that the conventional pipe 6 is not necessary. Since piping is not necessary in this way, it is possible to eliminate all the various conventional problems that have arisen due to the piping.
In addition, the hydraulic pump P of the clamping mechanism R only needs to be operated when the clamping mechanism R releases the clamping force. In other words, when the clamping mechanism R maintains the clamping force by the spring force of the spring 12, the hydraulic pump P can be stopped, and the energy loss is reduced accordingly.
In addition, when releasing the clamping force of the clamping mechanism R, there is no activation delay of the electric motor M, so that the working speed of the entire apparatus is also maintained.
[0019]
In this type of machine tool tool changer, for example, when it is used in an automobile production factory, the tool change speed is particularly problematic. For this reason, the startup delay of the conventional electric motor greatly affects the working speed of the entire apparatus. However, according to this embodiment, there is no need to make the startup delay of the electric motor a problem.
[0020]
The second embodiment shown in FIG. 3 differs from the first embodiment in that a pressure switch 24 is used as a position detection mechanism and an accumulator 25 is connected.
The pressure switch 24 operates in accordance with the pressure in the upper chamber 13b of the cylinder 13. That is, when the pressure in the upper chamber 13b is equal to or lower than the set pressure, the off state is maintained, and when the pressure is higher than the set pressure, the on state is maintained.
For example, when the clamp releases the clamping force, the rod 11 reaches the stroke end, so that the pressure in the upper chamber 13b increases. The pressure switch 24 detects this increased pressure, maintains the ON state, and inputs the signal to the controller C. The controller C that has received the ON signal in this manner switches the control valve v after the set time has elapsed, as in the first embodiment.
The accumulator 25 is for preventing the circuit pressure from being lowered due to oil leakage in the circuit.
[0021]
【The invention's effect】
According to the apparatus of the present invention, since the control valve, the hydraulic pump, the tank, and the electric motor are integrated and fixed to the cylinder, piping between the control valve and the cylinder becomes unnecessary. Since piping is not necessary in this way, it is possible to eliminate all of the various conventional problems that have been caused by piping.
Further, when the clamping mechanism maintains the clamping force by the spring force of the spring, the hydraulic pump can be stopped, and energy loss is reduced accordingly.
Furthermore, since the electric motor that drives the hydraulic pump is rotated before the clamping mechanism releases the clamping force, the activation delay is eliminated. Since the start-up delay is eliminated, the work speed of the entire apparatus is also increased.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a main part of a first embodiment.
FIG. 2 is a circuit diagram of the first embodiment.
FIG. 3 is a circuit diagram of a second embodiment.
FIG. 4 is a circuit diagram of a conventional exchange device.
[Explanation of symbols]
A Auto tool changer R Clamp mechanism P Hydraulic pump M Electric motor T Tank v Control valve 10 Main body 11 Rod 13 Cylinder 18 Limit switch 19 Limit switch 24 Pressure switch

Claims (4)

A clamp mechanism that clamps a tool such as a cutting tool of a machine tool, and an auto tool changer that selects a target tool and conveys the tool to the clamp mechanism. The machine tool is configured to maintain the clamping force by the action of the spring force, while allowing the cylinder thrust to act on the rod against the spring force and to release the clamping force of the clamp mechanism with the rod thrust against the spring force. In the tool exchange apparatus, the cylinder is provided with a pair of passages, and a port is directly connected to the pair of passages to fix the control valve. The control valve includes a hydraulic pump and an electric motor for driving the hydraulic pump. a motor, while integrally attached to the tank, the electric motor is driven only when releasing the clamping force of the clamping mechanism And formed, and provided with a controller for controlling the operation procedure of the driving timing and the automatic tool changer of the electric motor, the controller, specific reference operation or auto tool changer clamping force releasing previous auto tool changer clamping mechanism A machine tool tool changer configured to activate the electric motor in accordance with the opening / closing operation of the door . The machine tool tool changer according to claim 1 , wherein the cylinder is provided with a movement amount detection mechanism, and the movement amount detection mechanism detects the movement position of the cylinder to control the control valve and the hydraulic pump. . The machine tool tool replacement apparatus according to claim 2, wherein the movement amount detection mechanism is a limit switch. The machine tool tool changer according to claim 2, wherein the movement amount detection mechanism is a pressure switch.

Images