JPH0448913Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a lifting object stopping device for instantaneously stopping an lifting object such as a spindle head located above a workpiece in a machine tool.

<Prior Art> In conventional machine tools, prevention of the spindle head, etc. from falling has been achieved by using only a mechanical brake device or by using a counterbalance device.

<Problem to be solved by the invention> In the above case, the object falls significantly between the time when the servo motor power is turned off and the mechanical brake device is turned on, and the servo is turned off while the object is still on the workpiece. If this happens, there is a possibility that an accident that could damage the workpiece may occur.

In view of the above-mentioned problems, the present invention attempts to instantaneously stop an ascending and descending object.

<Means for solving the problem> The means for solving the problem according to the present invention are as follows:
As shown in the figure, there is a mechanical brake device 7 for braking the lifting and lowering of the lifting object 5, which is provided on the machine tool body 1 so as to be able to move up and down, and a mechanical brake device 7 for braking the lifting and lowering of the lifting object 5 separately from the mechanical brake device 7. The electromagnetic brake device 8 is provided with a control device 9 for driving and controlling the mechanical brake device 7 and the electromagnetic brake device 8 at the same time.

The elevating object 5 includes, for example, an elevating nut 6 that is screwed into an elevating screw 2 that is rotatably installed on the machine tool body 1.
The lifting screw 2 is connected via a feed gear mechanism 3.
It is configured to be driven up and down by an NC servo motor 4, and braking is performed when the motor 4 is turned off.

<Operation> In the above problem solving means, when the mechanical brake device 7 and the electromagnetic brake device 8 are activated simultaneously, the mechanical brake device 7 starts up slowly, and the lifted object may fall before the brake starts to work. However, the power of servo motor 4 is turned off.
Immediately thereafter, the electromagnetic brake device 8 is raised at high speed, so that the electromagnetic brake device 8 can prevent the object 5 from falling suddenly. This method eliminates the need for a complicated counterbalance mechanism using hydraulics, pneumatics, etc.

<Example> Hereinafter, an example of the present invention will be described based on FIGS. 1 to 7. Fig. 1 is a configuration diagram of a lifting object stopping device for a machine tool showing one embodiment of the present invention;
The figure is a partially cutaway sectional view of the same mechanical brake device, and Figure 3 is a partially cutaway sectional view of the same electromagnetic brake device.
Fig. 4 is an electric circuit diagram of the lifting object stopping device, Fig. 5 a and b are braking timing charts of the mechanical brake device and electromagnetic brake device, respectively, and Fig. 6
The figure is an electric circuit diagram of the electromagnetic brake device, and FIG. 7 is a diagram showing braking current characteristics of the electromagnetic brake device.

As shown in the figure, the lifting object stopping device for a machine tool according to the present invention includes an lifting screw 2 rotatably installed on a machine tool body 1, and a lifting screw 2 connected to a feed gear mechanism 3.
NC servo motor for rotational drive through 4
and a lifting nut 6 fixed to the lifting object 5 and screwed onto the lifting screw 2 to raise and lower the lifting object 5;
a mechanical brake device 7 for controlling the rotation of the lifting screw 2; an electromagnetic brake device 8 for controlling the rotation of the lifting screw 2 separately from the mechanical brake device 7; The mechanical brake device 7 and the electromagnetic brake device 8
It is equipped with a control device 9 for simultaneously driving the two.

The motor 4 is connected to a feed gear mechanism 3 on the upper part of the main body 1.
is placed on the gearbox 3A. Lifting screw 2
The drive gear 3B of the feed gear mechanism 3 is fixed to the upper end, and the mechanical brake device 7 and the electromagnetic brake device 8 are arranged at the upper end of the lifting screw 2.

The mechanical brake device 7, as shown in FIG.
Consisting of a stationary part 11 and a rotating part 12, the stationary part 11
consists of a yoke 14 with a built-in coil 13 and an armature 16 that slides in the axial direction with respect to the yoke 14.
, an outer disk 17 and a plate 18 , and several operating springs 19 are inserted between the yoke 14 and the armature 16 .

The rotating part 12 is composed of an inner disk 20 and a spline hub 21, which are engaged with each other at an internal spline 22, so that the inner disk 20 can slide in the axial direction.

The electromagnetic brake device 8, as shown in FIG.
This is a dry single-plate, excitation-operated electromagnetic brake, and is composed of one stationary part 23 and one rotating part 24.

The stationary part 23 includes a field 26 containing an electromagnetic coil 25 and a friction plate 27 integrated with a screw 28, and is fixed to the case 3A by a flange 29.

The rotating part 24 is composed of an armature 30 and a spline hub 31, and the armature 30 meshes with the spline hub 31 attached to a shaft 32 so as to be able to slide in the axial direction. In the figure, 33 is a release spring.

The control device 9 is configured as shown in FIG. 4, for example. That is, the first relay contact S1 is connected in series to the coil 13 of the mechanical brake device 7,
A first relay coil C1 that turns the first relay contact S1 ON and OFF is connected in series with a first switch W1 for the motor 4 (closed when normal) and an emergency stop switch W2 (open when stopped in an emergency).

On the other hand, in parallel with the first relay coil C1, it is ON for a short time when the emergency stop switch W2 is OFF (opened).
A timer switch TR is connected, and the timer contact T1, which is turned ON by the ON signal of the timer switch TR, and the second relay coil C2 of the electromagnetic brake device 8 are connected in series. Furthermore, a parallel connection body of a second switch W3 for emergency stop, which is closed during an emergency stop, and a second switch W4 for the motor 4, which is closed when the servo motor 4 is abnormal, is connected to this timer contact T1.

The coil 25 (rated voltage DC 24V) of the electromagnetic brake device 8 is connected in series with the second relay contact S2, which is turned ON by excitation of the second relay coil C2, and these series connections are connected to the AC power source AC by the rectifier circuit 35. connected via. The coil 25 of this electromagnetic brake device 8 is an overexcitation circuit, and as shown by the solid line A in FIGS. 6 and 7, the coil 25 of the electromagnetic brake is a circuit that applies a voltage higher than the rated voltage (quadruple voltage) to the electromagnetic brake. A current larger than the rated value flows through 25. In addition, SW in FIG. 6 indicates a switch that is turned on during operation. Further, in FIG. 7, the diagram indicated by the dotted line B shows the rise of the current when a standard voltage is applied.

In the above configuration, when the servo motor 4 is in the ON state, the elevating object 5 is held in its position by the servo lock function of the servo motor 4.

If you turn off the servo motor 4 from this state,
The servo locking ability is lost, and the weight of the lift 4 rotates the motor 4 via the lift screw 6 and gear.
The elevating object 5 falls.

The mechanical brake device 7 is free to rotate when the power is turned on, and when the power is turned off, the armature 16 and disks 17, 20 are activated by the force of the built-in spring 15 to bring it into a braking state. This braking characteristic consumes the entire power supply of the machine tool.
This is necessary to prevent the lifting object 5 from falling even when it is turned off.

Since the mechanical brake device 7 moves the armature 16 and disks 17, 20 by the force of the spring 19, it takes a long time from when the power is turned off to when the maximum braking ability is exerted. Therefore, if only the mechanical brake device 7 is used, the amount of fall will be large.

Therefore, in order to add the electromagnetic brake device 8 and further shorten the start-up time of the electromagnetic brake device 8, we added a voltage several times the rated voltage (within the short-time rating) and the mechanical brake device 7 started up. The electromagnetic brake is used to restrain the falling force until the object 5 ascends, thereby preventing the object 5 from falling, which conventionally would have fallen significantly.

In addition, in the mechanical brake device 7, the plate 18
The outer 17 and the inner disk 20 between the armature 16 and the armature 16 are pressed together by a constantly operating spring 19, and the rotating portion 12 is braked by the frictional force thereof. When energized, the yoke 14 is excited and the electromagnetic force is applied to the spring 1.
Overcoming the power of 9 and suctioning armature 16,
Increase the distance between the plate 18 and the armature 16,
A gap is created between the outer disk 17 and the inner disk 20, and the rotating part 12 is made free.

When the power supply is cut off, the armature 16 is pushed back by the operating spring 19, presses the inner 20 and the outer disk 17, and brakes the rotating part 12.

Further, in the electromagnetic brake device 8, the coil 25
When energized, magnetic flux is generated and the friction plate 27 integrated with the field 26 is magnetized. That is, the friction plate 27 and the armature 27 are in close contact with each other, and the rotating portion 24 is braked by the friction.

In the non-excited state, the rotating part 2 is closed by the release spring 33.
4 is free.

In this way, when the servo of the object 5 that is raised or lowered by the NC servo feed mechanism is turned off, the object 5 is prevented from falling by the dual brake mechanism that includes an electromagnetic brake in addition to a fall prevention mechanism using a mechanical brake. I try to stop it instantly.

It should be noted that the present invention is not limited to the above embodiments, and it goes without saying that many modifications and changes can be made to the above embodiments within the scope of the present invention. For example, the control device is not limited to the configuration of the above embodiment, but may be of a more simplified configuration.

<Effects of the invention> As is clear from the above explanation, in the present invention, when a mechanical brake device and an electromagnetic brake device are operated at the same time, the mechanical brake device starts up slowly and takes a long time until the brake starts to work. However, since the electromagnetic brake device is started up at high speed immediately after the servo motor is powered off, this electromagnetic brake device can prevent the objects from falling suddenly. Furthermore, it has the advantage of eliminating the need for a complicated counterbalance mechanism using hydraulics, pneumatics, etc.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a lifting object stopping device for a machine tool showing an embodiment of the present invention, Fig. 2 is a partially cutaway sectional view of the same mechanical brake device, and Fig. 3 is an illustration of the same electromagnetic brake device. Fig. 4 is an electric circuit diagram of the lifting object stopping device, Fig. 5 a and b are braking timing charts of the mechanical brake device and electromagnetic brake device, respectively, and Fig. 6 is the electrical diagram of the electromagnetic brake device. The circuit diagram, FIG. 7, is a diagram showing braking current characteristics of the electromagnetic brake device. 1... Machine tool body, 2... Lifting screw, 3...
Feed gear mechanism, 4... NC servo motor, 5...
Lifting object, 6... Lifting nut, 7... Mechanical brake device, 8... Electromagnetic brake device, 9... Control device.

Claims (1)

[Scope of utility model registration request] A mechanical brake device for braking the lifting and lowering of an elevating object, which is provided on a machine tool body so as to be able to rise and lower; an electromagnetic brake device for braking the lifting and lowering of the elevating object separately from the mechanical brake device; and the machine. 1. A lifting object stopping device for a machine tool, comprising a control device for simultaneously driving and controlling an electromagnetic brake device and an electromagnetic brake device.