JPH10112971A - Mechanical breaking mechanism of linear motor traveling shaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To install mechanical breaking mechanism which is compact and can obtain sufficient breaking force with excellent response when a power source is interrupted. SOLUTION: When a power source is broken by service interruption accident or the like, a linear slider 1 retained on a linear guide 7 guided by a guide rail 10 turns into the state of coasting. At the same time, the attractive function of an attracting plate 3 of an electromagnet for holding the attracting plate is lost. A breaking unit containing a friction part member 5 is driven downward by the stretching force of a coil spring 8 and the self weight. An intensive attractive force from a fixed magnet 4 is applied to the magnetic field sensitive attracting plate 3, and the friction part member 5 is pressed against an external friction engaging part member 11. The running slider 1 rapidly decreases the speed and stops. When power is supplied again to the electromagnet 6 and operates an air cylinder mechanism 9, a piston 91 is driven upward, and abuts against the shoulder part 94 of a cylinder member 93. The attracting plate 3 is pulled upward and separated from the fixed magnet 4. Thereby the mechanical breaking is released.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanical brake mechanism for a linear motor traveling shaft, and more particularly, to a mechanical brake mechanism for a linear motor traveling shaft utilizing a magnetic attraction provided in a linear motor. The present invention is advantageously applied to, for example, a moving mechanism of a machine tool or an industrial machine.

[0002]

2. Description of the Related Art As is well known, a linear motor is characterized in that a propulsive force for directly moving a movable slider along a track on which a fixed slider having a fixed magnet or a coil is provided is obtained. . Therefore, since the linear motor was developed, it has been expected to be widely used as a drive source for general machines such as machine tools. However, the adoption of linear motors in general machines has not progressed as expected.

One of the reasons is that the introduction of a mechanical brake is delayed for a traveling axis driven by a linear motor. Needless to say, the linear motor can electrically perform rapid deceleration and sudden stop without using a mechanical brake, but only when the linear motor is under the control of the controller. That is, when an accident such as a power failure or disconnection occurs during the operation of the linear motor and the signal for controlling the linear motor is interrupted, there is a high possibility that the operation by the controller becomes impossible and the movable slider continues to coast. .

Therefore, when a linear motor traveling shaft having no deceleration / stopping means other than the electric brake is employed in a general machine, there is a lack of a function that the general machine basically has, that is, "stops when power is turned off". This makes it difficult to ensure safety for workers and peripheral devices. The most common solution to this problem is to provide a brake friction member driven by an air cylinder on the linear motor traveling shaft and apply braking to an external friction engagement member provided around the brake to perform braking. It is.

[0005] However, the air cylinder has an advantage that a large braking force can be easily obtained, but has a poor responsiveness in consideration of the time required for air movement. Even if the air is shut off together with the electricity, the emergency brake cannot be said to be a reliable safety mechanism unless it is always activated. For these reasons, there is a problem in employing an air cylinder as an actuator for a brake that operates in an emergency.

In addition, there are a method of providing an electromagnetic brake mechanism using an electromagnet and a spring, and a method of using a hydraulic mechanism. However, if a large surface pressure is maintained during the operation of the brake, it is inevitable that the entire traveling apparatus becomes large, and practical use is not possible. Was difficult.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a mechanical brake for a linear motor traveling shaft capable of obtaining sufficient braking force with good responsiveness with a simple structure without enlarging the entire traveling device. It is to provide a mechanism.

[0008]

According to the present invention, a mechanical brake mechanism mounted on a linear motor traveling shaft according to the present invention comprises a suction member having a magnetic field-sensitive attraction and a suction member attached to a traveling slider of the linear motor traveling shaft. Suction member supporting means for detachably supporting a fixed magnet disposed along the axis, suction member separation holding means for releasably holding the suction member at a position separated from the fixed magnet, and suction. A friction member provided on the member, an external friction engagement member disposed along the linear motor travel axis and capable of frictionally engaging the friction member, and a suction member for driving the suction member in a direction away from the fixed magnet. External actuator means.

When the power supply of the linear motor traveling shaft is cut off or an emergency stop is required, the suction member separation holding function of the suction member separation holding means is released, and the suction member moves spontaneously to a position close to the fixed magnet. The friction member is pressed against the external friction engagement member by magnetic attraction acting between the suction member and the fixed magnet.

In a typical embodiment, an extensible elastic member is used for the suction member supporting means, and the suction member separation holding means holds the suction member at a position separated from the fixed magnet during power supply, Electromagnetic means for releasing the suction member separation holding function when power is not supplied is used.

Preferably, the external actuator means includes an air cylinder mechanism. It is preferable that a sheet member for preventing direct contact between the attraction member and the fixed magnet is interposed between the attraction member and the fixed magnet.

Since the mechanical brake mechanism of the present invention also uses the fixed magnet which is originally required for driving the linear motor as a source for generating a braking force, it is necessary to provide an external actuator for obtaining a large braking force as before. Absent. When the power is turned off, the suction member separation holding function of the suction member separation holding means is released, and the brake is reliably activated.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. Note that the reference numerals assigned to the respective elements are common throughout FIGS. First, FIG. 1 and FIG. 2 are views illustrating a running state of a linear motor traveling shaft equipped with a mechanical brake mechanism according to the present embodiment, and FIG. 1 shows a schematic structure of a main body portion along a traveling direction. FIG. 2 shows a schematic structure of the main body in a cross-sectional view along a direction perpendicular to the running direction.

In FIG. 1 or FIG. 2, the traveling slider (movable slider) designated by reference numeral 1 is a linear guide 7.
Are provided on both sides, and the linear guide 7 is slidably engaged with each of the two guide rails 10 laid on the installation surface. Between the two guide rails 10, a fixed magnet 4 composed of a number of permanent magnet segments having alternating polarities is disposed.

A coil (not shown) is provided inside the traveling slider 1 so as to generate a linear motor thrust in the traveling axis direction (vertical direction in FIG. 2) by interaction with the fixed magnet 4 when excited. I have. The exciting current is supplied from the power supply unit via the controller in a known manner.

In order to equip a linear motor traveling shaft having such a basic structure with a mechanical brake mechanism, a suction plate 3 is movably connected to the traveling slider 1 via an extensible coil spring 8. At least a part of the suction plate 3 is made of a material having a magnetic field-sensitive suction property (a property of being sucked in response to a magnetic field) such as iron, for example, and friction members 5 are provided on both sides. An external friction engagement member 11 is laid on the belt-like area on the installation surface facing the friction member 5 when the traveling slider 1 travels, to which the friction member 5 is pressed when the brake is effective. Also, one or both of the suction plate 3 and the fixed magnet 4 are provided with a sheet member 2 for protecting them from damage due to direct contact.

Further, the traveling slider 1 is provided with an attraction plate holding electromagnet 6 at a position aligned with the coil spring 8. The attracting plate holding electromagnet 6 receives the supply of the exciting current from the power supply unit via the controller except when the mechanical brake is effective,
The suction plate 3 generates a force for pulling the suction plate 3 by overcoming the tension of the coil spring 8 and the weight of the entire brake unit.
At a position separated from the fixed magnet 4.

In response, the friction member 5 and the external friction engagement member 11 are kept separated. In addition, the suction force that the suction plate 3 receives from the fixed magnet 4 at this separated position is very weak, and there is substantially no need to brake the traveling slider. In this way, the mechanical brake is kept ineffective and the friction member 5 is kept off during the linear motor running or during the normal stop where the power supply to the suction plate holding electromagnet 6 is maintained.
And the external frictional engagement member 11 maintain the separated state.

The mechanical brake mechanism in this embodiment is
An air cylinder mechanism 9 is provided as brake release means for releasing the brake once activated. The main part of the air cylinder mechanism 9 is composed of a main body 90, a piston 91, and a cylinder member 93 having a cavity 92 and a shoulder 94 narrowing the cavity. The main body 90 is a support member 1
The cylinder member 93 is fixed to the suction plate 3 while being fixed to the traveling slider 1 side via the slider 2 and is fitted to the traveling slider 1 via an appropriate bearing (not shown). A well-known piston expansion and contraction mechanism driven by compressed air is built in the main body 90.

When the piston expansion / contraction mechanism of the main body 90 is actuated by an air supply signal from the controller, the piston 91 slides upward in the cavity 92 in the figure. When the piston 91 contacts the shoulder 94 of the cylinder member 93 and continues to slide, the suction plate 3 connected to the cylinder member 93 is driven upward (separated from the fixed magnet 4) in the figure.

Next, the operation when the mechanical brake mechanism is activated and deactivated (released) according to the present embodiment will be described with reference to FIGS. 3 and 4. FIG. 3, FIG.
FIG. 3 is a cross-sectional view similar to FIG. 2 showing a state where the mechanical brake of the linear motor traveling shaft described with reference to FIG. 2 is activated. FIG. 4 is a cross-sectional view similar to FIGS. 2 and 3 showing a state in which the brake effective state shown in FIG. 3 is released. 3 and 4, the description of the connection relationship with the controller / power supply is omitted.

Now, let us consider a case where all power supplies are cut off due to a failure of the controller, an accident such as a disconnection or a power failure, or an emergency stop button being pressed in the running state shown in FIGS. In response, the next event occurs quickly and spontaneously, and the linear motor (linear slider 1) immediately stops.

First, when the power supply to the coil in the linear slider 1 is stopped, the linear thrust is lost, and the linear slider 1 enters a coasting state (more precisely, a slight braking state). At the same time, the power supply to the attraction plate holding electromagnet 6 is cut off, so that the attraction function of the attraction plate 3 is lost, and the tension force of the coil spring 8 and the gravitational action cause the brake unit including the attraction plate 3 and the friction member 5. The whole starts moving toward the installation surface.

As the attraction plate 3 approaches the fixed magnet 4, the attraction plate 3 having the magnetic field-sensitive attraction becomes strongly attracted to the fixed magnet 4, and the approaching movement of both is accelerated. Eventually, as shown in FIG. 3, the friction members 5 provided on both sides come into contact with the external friction engagement member 11 and are then strongly pressed. As a result, a strong braking action based on the friction between the friction member 5 and the external friction engagement member 11 is exerted, and the traveling slider 1 rapidly decelerates and stops within a short time.

After the traveling slider 1 stops, the attraction force of the attraction plate 3 and the fixed magnet 4 is maintained, and the pressing state between the friction member 5 and the external friction engagement member 11 is maintained. Effective state is maintained naturally. That is, the mechanical brake is enabled and stably maintained without relying on the operation of the external actuator at all.

In order to release the brake effective state shown in FIG. 3, an air cylinder member mechanism is used as an external actuator. That is, when the brake is released, the power supply to the suction plate holding electromagnet 6 is restarted, the air cylinder mechanism 9 is operated, and the piston 91 is driven upward in the drawing.
After the piston 91 comes into contact with the shoulder 94 of the cylinder member 93, the suction plate 3 connected to the cylinder member 93 receives a force of strongly lifting upward in the drawing, and overcomes the suction force from the fixed magnet 4 to fix the fixed magnet. 4 and at the same time, the friction member 5 is disengaged from the external friction engagement member 11, and the friction engagement is released.

When the suction plate 3 is sufficiently far from the fixed magnet 4 and the brake unit can be held only by the suction force of the suction plate holding electromagnet 6, the driving of the piston 91 by the air cylinder mechanism 9 is stopped, As soon as power is supplied to the coil in the traveling slider 1, the traveling slider 1
The vehicle returns to a state in which the vehicle can travel.

Finally, some supplementary explanations will be given regarding the air cylinder used as the external actuator in the present embodiment. The air cylinder mechanism main body 90 shown in each figure is a complete drive mechanism by itself, and no air flows in and out of the other related elements 91 to 94. The piston 91 is directly connected to the rod of the air cylinder mechanism main body 90, and is connected to the air cylinder mechanism main body 90.
The piston 91 is driven by the flow of air into and out of the interior (the cavity of the cylinder element).

When the slider is running (see FIG. 2),
There is a cavity 92 between the piston 91 and the shoulder 94, and when the brake is operated (see FIG. 3), the piston 91 is moved by the amount of movement of the entire brake unit including the suction plate 3 and the friction member 5 toward the installation surface. It can be considered that a cavity 92 is generated between the suction plate 3 and the suction plate 3.

When the slider is running, the piston 91 is in an extended state (hanging state) so that the piston 91 does not contact the shoulder 94 when the brake is operated and the whole unit moves. Then, as described above, when the brake is released, the air cylinder (the main body portion 90) is operated to engage the piston 91 with the shoulder portion 94 and pull up the entire brake unit.

After the electromagnet 6 is energized and the entire brake unit is held, the air cylinder (main body 90) is operated again to extend the piston 91, so that the piston 91 separates from the shoulder 94, and the normal operation ( (Running) can be resumed.

Although the embodiment of the present invention has been described, the source of the braking force is merely the magnetic attractive force acting between the attracting member (the attracting plate 3 in the above embodiment) and the fixed magnet. The above embodiments are not intended to limit the present invention. Therefore, if the condition that a sufficient magnetic attraction force acts between the attraction member (attraction plate 3) and the fixed magnet is satisfied, the coil spring 8 does not necessarily need to be extensible, and in some cases, the attraction member (For example, a guide mechanism of an attraction member) for supporting the fixed magnet so as to be detachable from the fixed magnet may be employed.

As for the external actuator for releasing the brake, it is preferable to use an air cylinder mechanism as in the above embodiment, but it is also possible to use another type of actuator (for example, an electromagnetic plunger for driving a suction member). is there.

[0034]

According to the present invention, since a fixed magnet which is originally required for driving a linear motor is also used as a source for generating a braking force, a compact mechanical brake mechanism capable of obtaining a large braking force with good responsiveness is provided. I can do it.
Further, the mechanical brake mechanism of the present invention can automatically activate the brake when the power is cut off, so that the safety of the device using the linear motor traveling axis can be enhanced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view along a traveling direction showing a traveling state of a linear motor traveling shaft equipped with a mechanical brake mechanism according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along a direction perpendicular to a traveling direction of a linear motor traveling shaft equipped with a mechanical brake mechanism according to an embodiment of the present invention when traveling.

FIG. 3 is a cross-sectional view along a direction perpendicular to a traveling direction of a linear motor traveling axis equipped with a mechanical brake mechanism according to an embodiment of the present invention when a brake is effective.

FIG. 4 is a cross-sectional view taken along a direction perpendicular to the traveling direction of a linear motor traveling axis equipped with a mechanical brake mechanism according to an embodiment of the present invention when the brake is released.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 traveling slider 2 sheet member 3 suction plate 4 fixed magnet 5 friction member 6 electromagnet for holding suction plate 7 linear guide 8 coil spring 9 air cylinder mechanism 10 guide rail 11 external friction engagement member 12 support member 90 air cylinder mechanism body 91 piston 92 cavity 94 shoulder 93 cylinder member

Claims (5)

[Claims] 1. A mechanical brake mechanism for a linear motor traveling shaft, comprising: a suction member having a magnetic field-sensitive attraction; and a suction member disposed on a traveling slider of the linear motor traveling shaft along the linear motor traveling shaft. Suction member supporting means for detachably supporting the fixed magnet provided; suction member separation holding means for releasably holding the suction member at a position separated from the fixed magnet; and on the suction member. A friction member disposed along the linear motor travel axis, and an external friction engagement member capable of frictionally engaging with the friction member; and driving the suction member in a direction away from the fixed magnet. An external actuator means for turning off the suction member of the suction member separation holding means when the power of the linear motor traveling shaft is shut off or an emergency stop is required. The holding function is released, the suction member moves spontaneously to a position close to the fixed magnet, and the friction member is moved by the magnetic attraction force acting between the suction member and the fixed magnet. A mechanical brake mechanism for the linear motor traveling shaft, the mechanical brake mechanism being pressed against the joint member. 2. The mechanical brake mechanism of a linear motor traveling shaft according to claim 1, wherein said suction member supporting means is an extensible elastic member. 3. The electromagnet means, wherein the suction member separation holding means holds the suction member at a position separated from the fixed magnet during power supply, and releases the suction member separation holding function when power is not supplied. A mechanical brake mechanism for a linear motor traveling shaft according to claim 1 or 2. 4. The mechanical brake mechanism of a linear motor traveling shaft according to claim 1, wherein said external actuator means comprises an air cylinder mechanism. 5. A sheet member for preventing direct contact between the attraction member and the fixed magnet is interposed between the attraction member and the fixed magnet.
A mechanical brake mechanism for a linear motor traveling shaft according to any one of the preceding claims.