JP2001162479A - Slider braking device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-size slider braking device allowing actual arrangement and capable of stopping a free fall of a linear-movement large-size up-and- down slider of a high-precision machine tool. SOLUTION: This slider braking device brakes the linear-movement slider 1 supported by a support block and linearly moving. The slider braking device has a rod 2 fixed to one of the support block and the linear-movement slider 1; a nearly cylindrical and radially movable brake pad 7 disposed around the rod 2; and a brake housing 4 fixed to the other of the support block and the linear-movement slider 1, retaining the brake pad 7. By applying force to the peripheral face of the brake pad 7, the brake pad 7 is pressed to the rod 2 to generate brake force.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake device used for a linear motion slider for moving a tool or a work of a machine tool, and more particularly to a brake device used for a large vertical slider of a precision machine tool.

[0002]

2. Description of the Related Art Conventionally, a linear motion slider for a work shaft or a tool shaft of a machine tool is supported by a rolling or sliding guide, and is driven by a ball screw or a linear motor. When the slider is used for the vertical axis, a counterweight or a cylinder is used to compensate for its own weight.

[0003] As a brake for such a direct-acting vertical slider, a type in which a ball screw driving motor or a speed reducer is held by a disc brake or the like is used. Is disposed between a disk pad which is arranged outside and is driven by an air cylinder or the like.

[0004]

However, in a high-precision machine tool, high positioning accuracy and trajectory followability are required. Therefore, advanced feed control by laser feedback of the position is required, and the feed system has no friction. Is required. Therefore, the motor is driven by a linear motor, and a method of fixing the rotation of a ball screw driving motor or a reduction gear as a brake cannot be adopted.

[0005] Further, the vertical slider of a high-precision machine tool is of a large size with a built-in main spindle, or a vertical slider whose weight is intentionally increased in order to increase the dynamic rigidity in a high frequency region. There is. In order to stop the free fall due to the accident of such a large vertical slider with a brake, in the method of sandwiching the plate, it is necessary to increase the cross-sectional area of the cylinder that drives the disk pad. Invite. Further, when the size of the brake unit is increased, it is not possible to dispose the brake at a position that is well balanced with respect to the slider, and a large moment acts upon stopping to damage the guide system and the drive system.

For example, in order to stop the free fall of a 300 kg vertical slider with two brake units, if the friction coefficient between the disk pad and the plate is 0.2 and the safety factor is 1.5, the pressing force is 225 kg. is necessary. When using air pressure, supply pressure is 0.8MP
Assuming a, the pressed area is about 140 cm ² . If the width of the plate attached to the side surface of the slider is set to a maximum of 50 mm as a realistic value, the corresponding disk pad becomes 50 m.
m × 280 mm, and a pressure of 0.8 MPa must be applied to the entire area. The plate needs to have a length which is further added to the stroke of the slider (for example, 200 mm), and is extremely large as a brake unit, and cannot be arranged substantially near the slider.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above-mentioned problem, and has as its object to stop a free-fall of a large linear slider for linear motion of a high-precision machine tool, and to provide a small, practically disposable slider. An object of the present invention is to provide a brake device for a slider.

[0008]

Means for Solving the Problems To solve the above-mentioned problems,
In order to achieve the object, a brake device for a slider according to the present invention is a brake device for a slider for applying a brake to a linear slider which is supported by a support and moves linearly, wherein the support or the linear slider is provided. And a substantially cylindrical brake pad disposed around the rod and displaceable in a radial direction, and a brake fixed to the other of the support base and the linear slider to hold the brake pad And a housing, wherein a force is applied to an outer peripheral surface of the brake pad, and the rod is pressed against the rod to generate a braking force.

Further, in the brake device for a slider according to the present invention, the fluid is caused to flow into a pressure chamber provided between the outer peripheral surface of the brake pad and the brake housing, and the pressure in the pressure chamber is increased. A brake pad is pressed against the rod.

Further, in the brake device for a slider according to the present invention, the brake pad is a split cylindrical ring.

In the brake device for a slider according to the present invention, the rod is fixed to an upper surface of the linear motion slider, and the brake pad and the brake housing are built in a fixed column disposed above the linear motion slider. It is characterized by being.

In the brake device for a slider according to the present invention, the rod is formed of carbon steel, and the brake pad is formed of a soft metal.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a view showing the configuration of an embodiment of a slider brake device according to the present invention.

In FIG. 1, reference numeral 1 denotes a slider which moves up and down, and 2 denotes a cylinder rod which is fixed to the upper surface of the slider and moves together with the slider. Reference numeral 3 denotes a fixed column disposed above the slider, and a brake housing 4 is bolted to the fixed column 3. An O-ring groove 5 is formed in the brake housing 4 so that a rectangular outer peripheral frame is wound around a cylindrical surface, and an O-ring 6 is inserted along the O-ring groove 5. Reference numeral 7 denotes a cracked cylindrical brake pad.
In contact with the ring. Thereby, the pressure chamber 8 including the brake housing, the O-ring, and the brake pad is formed.

An air supply hole 9 for supplying air from outside is connected to the pressure chamber 8. In order to stop the re-slider due to an accident or abnormality of the machine tool, an open command is issued to the servo valve 11 by pressing an emergency stop button of the operation panel 10, and a pressure is supplied from an external air supply source (not shown) through the air supply hole 9. High-pressure air is supplied to the chamber 8. As a result, pressure is evenly applied to the outer peripheral surface of the cylinder of the brake pad 7, contracts in the radial direction, comes into contact with the entire cylinder rod 2, and the cylinder rod 2, that is, the slider 1 can be stopped by the frictional force. Numeral 12 denotes an elastic body made of hard rubber or the like for preventing the attitude of the slider from changing. Since the brake pad 7 is relatively softly supported by the O-ring 6 and the elastic body 12, even when the cylinder rod 2 is gripped,
There is no possibility that the guide portion is galled by changing the attitude of the slider 1.

FIG. 2 is a view showing an operation state of the brake, FIG. 2 (a) shows a brake release state, and FIG.
Indicates a brake operating state.

In FIG. 2A, the pressure chamber 8 is in an atmospheric pressure state, and there is a gap 13 between the brake pad 7 and the cylinder rod 2. In this state, when high-pressure air is introduced into the pressure chamber 8 from the air supply hole 9, the brake pad 7 contracts in the radial direction as shown in FIG. At this time, the crushing allowance of the O-ring 6 is reduced by an amount corresponding to the contraction of the brake pad 7. Therefore, the initial gap 13 needs to be within the allowable value of the crushing allowance of the O-ring 6. If the nominal diameter of the O-ring 6 is at a level of φ100 mm, the gap 1
3 is preferably about 0.1 mm. Since the brake pad is an elastic body, when the high-pressure air is exhausted, the brake pad is restored to its original shape by the spring property.

The braking force of the brake pad 7 is determined by the pressing force of the brake pad 7 against the cylinder rod 2 multiplied by the coefficient of friction.
Determined by pressure. In this configuration, since the area of the brake pad 7 is a cylindrical surface, the projection area can be reduced to about one-third in comparison with the type in which the brake pad 7 is pressed flat to obtain the same braking force.

The brake pad 7 and the cylinder rod 2 are
It is desirable that one has high hardness and the other has low hardness.
In the present configuration, the cylinder rod 2 is formed by applying electroless nickel plating to a carbon net to make the surface of the cylinder rod 2 hard, and the brake pad 7 is made of a soft metal such as phosphor bronze. According to this combination, even at the time of contact between the two, the cylinder rod 2 side is hardly scratched, and the brake pad 7 side is hardly burred even if scratched.

FIG. 3 is a view showing an example in which the brake device of one embodiment is incorporated in a high-precision vertical slider for a machine tool.

In FIG. 3, reference numeral 1 denotes an upper and lower slider.
The main shaft 14 is mounted at the center. 15a and 15b are columns having guide portions. The slider 1 is supported by a static pressure bearing 16 and a guide in a direction other than the traveling direction.
Reference numeral 17a denotes a stator coil of a feed driving linear motor, 1
7b is a moving magnet of a linear motor, 18 is a cylinder for compensating its own weight, and 19 is a cylinder rod for compensating its own weight fixed to the columns 15a and 15b. There is a gap of about 10 μm between the self-weight compensation cylinder 18 and the cylinder rod 19 to form a non-contact air cylinder.
Reference numeral 20 denotes a laser interferometer for measuring the position of the slider, and reference numeral 21 denotes a laser reflecting mirror fixed to the slider. The drive system, the position measurement system, and the weight compensation system are arranged in four sets at four corners of the slider 1.

Since such a slider 1 has no friction at all, it has very high controllability, and a positioning accuracy on the order of nanometers can be expected. However, if any abnormality occurs in the control, especially if a control error occurs in the self-weight compensation, the worst case is a free fall state. In order to prevent this, the brake device of the present embodiment is mounted. The cylinder rod 2 is fixed to two positions on the left and right of the upper surface of the slider 1, and the brake unit 22 is fixed to the connection column 23. Brake unit 2
Since the slider 2 is arranged symmetrically with respect to the center of gravity of the slider 1, a moment is not generated in the slider 1 when the brake is actuated, and there is no harm to the guide system and the drive system. The structure of the brake unit 22 is as shown in FIG.

The weight of the slider 1 is 300 kg, and the braking force is 450 kg for safety. If this is to be handled by two brake devices, assuming that the friction coefficient is 0.2 and the supply pressure is 0.8 MPa, the diameter of the cylinder rod 2 is about φ90 mm, and the axial width of the brake pad 7 is 60 mm.
And a compact brake device having a large holding force can be realized.

In this embodiment, the cylinder rod 2
Moves and the brake pad 7 side is fixed, but if the slider 1 has a space for incorporating the brake unit,
Conversely, a configuration may be employed in which the cylinder rod 2 is fixed to the connection column 23 and the brake unit moves.

As described above, according to the above embodiment, the cylinder rod is fixed on the upper surface of the slider, and this is built in the fixed column disposed above the slider.
By applying pressure to the side surface of the cylindrical brake pad that can be displaced in the radial direction and pressing the entire inner surface of the cylinder of the brake pad against the cylinder rod, a large braking action can be obtained while being small.

According to this structure, the product of the area of the cylinder surface of the brake pad and the pressure applied thereto contributes to the frictional force, so that the projected area is smaller than that of the flat type brake pad for obtaining the same frictional force. And the entire brake unit can be downsized. In addition, since the brake unit can be arranged symmetrically with respect to the position of the center of gravity or the position of the center of gravity as viewed from the traveling direction of the slider, there is no possibility that the guide system or the drive system is damaged due to the moment acting at the time of stop.

[0028]

As described above, according to the present invention, a simple and compact brake device having a large braking force can be realized. Further, since the brake unit can be disposed at an appropriate position with respect to the slider, the guide system and the drive system of the slider are not damaged when the brake is operated.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of a slider brake device of the present invention.

FIG. 2 is a diagram showing an operation state of the brake device according to the embodiment.

FIG. 3 is a diagram illustrating an example of a brake device according to an embodiment mounted on a machine tool.

[Explanation of symbols]

 2 Cylinder rod 3 Fixed column 4 Brake housing 5 O-ring groove 6 O-ring 7 Brake pad 8 Pressure chamber 9 Air supply hole 10 Operation panel 11 Servo valve

Claims (5)

[Claims] 1. A slider brake device for applying a brake to a linear slider supported by a support table and moving straight, comprising: a rod fixed to one of the support table and the linear slider; An outer peripheral surface of the brake pad, comprising: a substantially cylindrical brake pad that is disposed around and that can be displaced in the radial direction; and a brake housing that is fixed to the other of the support base or the linear motion slider and holds the brake pad. A brake force is generated by applying a force to the rod to cause the rod to press the rod. 2. A method according to claim 1, wherein a fluid flows into a pressure chamber provided between an outer peripheral surface of the brake pad and the brake housing, and the rod is pressed against the rod by increasing a pressure in the pressure chamber. The brake device for a slider according to claim 1, wherein: 3. The brake device for a slider according to claim 1, wherein the brake pad is a broken cylindrical ring. 4. The linear slide according to claim 1, wherein the rod is fixed to an upper surface of the linear slide, and the brake pad and the brake housing are incorporated in a fixed column disposed above the linear slide. 2. The brake device for a slider according to 1. 5. The brake device according to claim 1, wherein the rod is formed of carbon steel, and the brake pad is formed of a soft metal.