JPS6077685A - Brake device - Google Patents

Abstract

PURPOSE:To improve the braking effect with a simple construction by producing a frictional force between a rod and an electrostrictive element by the increase in the volume of the element. CONSTITUTION:When a piston 28 is stopped, positive voltage is applied from lead wirings 44 to an electrode plate 40, and a negative voltage is applied from the lead wirings 46 to an electrode plate 42. Thus, a radial displacement is induced in a laminated ring-shaped electrostrictive element 36 to press a brake element 36. Accordingly, the element 36 presses the peripheral surface of a piston rod 26, thereby stopping the reciprocating operations. Since the radial displacement of the element 38 instantaneously occurs, the brake operation is performed substantially the same time as the application of the voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a brake device, and more particularly, the present invention relates to a brake device, and more particularly, a brake device that is disposed close to a driving iron constituting an actuator or the like or a driving iron connected thereto, and that controls the reciprocating movement, rotational movement, etc. of the driving iron. The present invention relates to a brake device such as an actuator for performing.

There are, for example, cylinders with positioners, lock amplifier cylinders, etc. that stop the cylinder rod that constitutes the actuator in the middle of reciprocating motion. A cylinder with a positioner that uses air can position the cylinder continuously or stepwise in proportion to an air pressure input signal by remote control, and is suitably used in process control and servo mechanisms. By the way, this cylinder with a positioner has a pair of diaphragms and a feedback spring, so it is structurally large and mechanically complicated. In other words, when trying to incorporate it into a process control device that makes effective use of a narrow space,
There are restrictions on the mounting method and mounting position, and furthermore, there are disadvantages in that the manufacturing cost cannot be reduced to a certain extent.

On the other hand, a lock-up cylinder is used to reliably lengthen a piston rod by increasing the inclination of a ring tilted by a spring force using cylinder thrust. This type of lock amplifier cylinder is suitably used for intermediate stops, emergency stops, fall prevention, etc. of piston rods.

However, as mentioned above, this lock-up cylinder has a complicated structure because it includes a lock amplifier ring tilted by a coil spring, and the ring itself is fitted so as to extend in the radial direction of the piston rod. The problem was that it was difficult to miniaturize because it was worn on people's clothes.

Therefore, as a result of intensive research and efforts, the present inventor focused on an electrostrictive element that is displaced in the thickness direction depending on the polarity of applied voltage, and stacked a plurality of electrostrictive elements close to the cylinder rod exposed to the outside of the cylinder. When an electrostrictive element is installed and a piston rod is to be stopped at a predetermined position, a voltage is applied to the electrostrictive element to increase the volume in the thickness direction, thereby creating a frictional force between the rod and the electrostrictive element. It has been found that a braking device for an actuator can eliminate the above-mentioned problems if it is configured to cause the rod to move forward or backward, thereby controlling the forward or backward movement of the rod.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a brake device that is small in size, has an extremely simple structure, can be manufactured at low cost, and has an excellent braking effect.

In order to achieve the above object, in the present invention, a piezoelectric element is disposed close to a shaft body that moves reciprocally or rotates, and the piezoelectric element is connected to a power supply circuit, and the piezoelectric element is set with a predetermined polarity. It is characterized in that the reciprocating motion or rotational motion of the shaft body is braked by the displacement caused by applying a voltage.

Next, preferred embodiments of the brake device according to the present invention will be described in detail with reference to the accompanying drawings.

In FIG. 1, reference numeral 10 indicates an air cylinder of a double-action quiz, and head covers 14 and 16 are fitted to both ends of a cylinder tube 12 constituting this air cylinder, respectively. A hose nipple 18 is fitted to the upper side of the head cover 14 for supplying driving air into the cylinder tube 12.
8 and 20 nuts are added together. Similarly, a hose nipple 22 is attached to the upper side of the head cover 16, and a bag nut 24 is further attached to the hose nipple 22.
There is a hearth. A piston rod 26 is provided inside the cylinder tube 12 so as to be able to reciprocate, and a piston 728t-1ift is attached to one end of the piston rod 26, and the other end of the piston rod 26 is connected to the outside. The mounting nut 30 is exposed and penetrated, and a nut 32 is further attached to the tip thereof.

Therefore, in the present invention, as described above, the cylinder tube 1
A brake device 34 is disposed adjacent to the piston rod 26 extending outward from the piston rod 26. The brake device 34 is a second
As can be seen from the figure, a ring-shaped braking element 36 made of rubber or synthetic resin is in direct pressure contact with the piston rod 26.
and a plurality of ring-shaped piezoelectric elements 38 stacked on the outside of the braking element 36. In this case, the electrode plates 4o, .
... are arranged and connected in parallel with each other through a lead wire 44 that connects each electrode plate 4o to the positive electrode, while electrode plates 42, . . . are connected in parallel with a lead wire 46 that connects to the negative electrode. I'll keep it.

Further, the braking element 36, the voltage element 38 and the electrode plate 40
．． 42 is entirely surrounded by a casing 48, and the lead wire 4
4.46 are led out to the outside through tube bodies 50.50 that fit into holes drilled in the casing 48, and connected to the positive and negative electrodes, respectively.

The present invention is basically constructed as described above, and its operation will be explained next.

When the air cylinder 10 is energized, the hose nipple 18.
Since a predetermined amount of air is fed into the cylinder tube 12 via the piston 22, the piston 28 reciprocates, and accordingly, the piston rod 26 reciprocates with a predetermined stroke. Therefore, when trying to control the position by stopping the piston 28 at a desired position, the brake device 34 of the present invention
is energized. That is, when the power supply circuit is closed via a relay (not shown), a positive voltage is applied to the electrode plate 40 from the lead wire 44, while a negative voltage is applied to the electrode plate 42 from the lead wire 46. Therefore, displacement in the radial direction is caused in the stacked ring-shaped voltage element 38,
As a result, in order to press the braking element 36, the element 36 comes into pressure contact with the circumferential surface of the piston rod 26 to prevent its forward or backward movement. Since the displacement of the piezoelectric element 38 in the radial direction occurs instantaneously, the braking action is performed almost simultaneously with the application of the voltage, thereby achieving desired position control.

FIG. 3 shows another embodiment of the invention. In this embodiment, the same reference numerals as in the previous embodiment indicate the same components.

In this embodiment, as can be easily understood from the figure, the ring-shaped stacked piezoelectric elements 38 are divided radially, and intervals 52 are defined between adjacent piezoelectric elements. Moreover, a highly rigid ring 54 is fitted to the outermost piezoelectric element to form the brake device 34.

When positive and negative voltages are applied to the polar plates 40 and 42 (not shown in this embodiment), the piezoelectric element 38 is displaced as described above, but in this case, the concentrated displacement inward in the radial direction is caused. I will do it. Therefore, the ring-shaped braking element 36 adjacent to the piston rond 26 is pressed, and the desired braking effect is achieved in the same manner as described above. In this embodiment, the spacing 52 serves to prevent the ends of the respective piezoelectric elements 38 oriented toward the piston condo 26 from coming into contact and preventing their displacement.

FIG. 4 shows yet another embodiment of the invention.

In this embodiment, a case is shown in which the rotational operation of a rotational drive shaft such as a motor is controlled in place of the piston rod 26. That is, four piezoelectric element groups 56.5 are stacked horizontally and vertically with respect to the center of the rotational drive shaft 55.
8.60.62 were placed close to each other facing each other. In this case, the layer closest to the rotary drive shaft 55 of each of the piezoelectric element groups 56, 58, 60 and 62 is a highly wear-resistant member 64.
It consists of

Therefore, when attempting to stop the rotating drive shaft 55 at a desired position, a voltage is applied with a predetermined polarity to a thin plate (not shown) disposed between the respective piezoelectric elements. The resulting piezoelectric element groups 56, 58, 60 and 62
If a total amount of displacement of 2 is applied to the drive shaft 55, the drive shaft 55 will be effectively prevented from rotating.

FIG. 5 shows yet another embodiment of the apparatus of the present invention.

In this embodiment, a disk-shaped disk 66 is attached to the rotary drive shaft 55 shown in FIG. 4, and piezoelectric element groups 68 and 70 are arranged opposite to each other in the vicinity of the rotating surface of the disk 66.

That is, when attempting to brake the drive shaft 55 rotated by a motor (not shown) or the like, the piezoelectric element group 68,70 close to the disk 66 is energized. As a result, the relatively soft and wear-resistant braking members 72, 74 attached to the tips of the piezoelectric element groups 68, 70 are mutually connected to the disk 66.
The desired braking effect can be obtained.

According to the present invention, as described above, it has become possible to brake the reciprocating motion and rotational motion of the shaft body of an actuator, etc. at a desired position with an extremely simple configuration, which is different from the conventional braking mechanism of an actuator, etc. Unlike the conventional method, the braking effect is further improved and the structure is simple, so that various remarkable effects can be obtained, such as being able to be manufactured at low cost and easily miniaturized.

Although the present invention has been described above with reference to a preferred embodiment, the present invention is not limited to this embodiment (for example, it may be used for positioning a valve body in a valve device, or may be used for using hydraulic pressure). It goes without saying that various improvements and design changes can be made without departing from the spirit of the present invention, such as being usable for controlling actuators used in the present invention.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway explanatory view of the device of the present invention installed in a double-acting type air cylinder, Fig. 2 is a partially enlarged view of Fig. 1, and Fig. 3 is an explanatory diagram of another device of the present invention FIG. 4 is a partially omitted perspective view showing an embodiment of the invention; FIG. 4 is a partially omitted perspective view showing yet another embodiment of the device of the present invention; FIG. FIG. 3 is an explanatory diagram in which a disc is mounted on a rotating shaft and the shaft is controlled by braking the disc. 10...Air cylinder 12...Cylinder tube 14.16...Head cover 18...Hose nipple 20...Bag 22...Hose nipple 24...Bag nut 26...Piston rono t'-28...Nand 3
0...Mounting nut 32...Nut 34...Brake device 36...Braking element 38...Piezoelectric element 40.42...Pole plate 44.46...Lead wire 48...
Casing 50... Pipe body 52... Spacing 54... Ring 55... Rotation drive shaft 56.58.60.62... Piezoelectric element group 64... Member
66... Disk 68.70... Piezoelectric element group 72.74... Braking member patent applicant Sintered Metal Industry Co., Ltd.

Claims (1)

[Scope of Claims] (1) A piezoelectric element is disposed close to a shaft body that moves reciprocally or rotates, and the piezoelectric element is connected to a power supply circuit, and a voltage is applied to the piezoelectric element with a predetermined polarity. A braking device that brakes the reciprocating motion or rotational motion of the shaft body by the displacement generated by the shaft body. (2. In the device described in claim 1, a braking element is attached to a piezoelectric element close to the shaft body, and the braking element is pressed against the shaft body under the bias of the piezoelectric element, so that the braking element is pressed against the shaft body. A brake device that brakes a reciprocating motion or a rotational motion. (3) The device according to claim 1, in which a plurality of piezoelectric elements are stacked in a ring shape. (4) Claims (5) The brake device according to claim 1, wherein the piezoelectric element has a plurality of radial spaces defined therein, and a ring body is fitted to the outermost part of the piezoelectric element. In the device, the piezoelectric element is a brake device consisting of at least two or more piezoelectric element groups arranged in the radial direction of the shaft. (6) In the device according to claim 1, the shaft is connected to the actuator. A brake device comprising connected drive shafts. (7) A brake device according to claim 6, wherein a disk is attached to the drive shaft and a group of piezoelectric elements is disposed close to the disk.