JPH0774642B2 - Intermediate stop device for rodless cylinder - Google Patents

Description

The present invention relates to an intermediate stop device for a rodless cylinder,
More specifically, the present invention relates to an intermediate stop device that selectively engages a brake shoe with a force expanded by an eccentric shaft to a fixed guide member provided along the moving direction of a piston.

(B) Conventional technology In a so-called rodless cylinder without a piston rod, an intermediate stop device for stopping the piston at an arbitrary position has been conventionally provided. As an example of such a conventional intermediate stop device, there are those described in JP-A-62-180104 and JP-A-61-241506.

As shown in FIG. 6, the above-described one is provided with a pair of brake rods b rotatably in parallel with each other along the cylinder tube a of the rodless cylinder so as to rotate the rod b. The cylinder rod a is provided with a driver d on the outside of the cylinder tube a, and the driver d is connected to the piston so as to move together. The brake rod b penetrates the protrusion e formed on the driver d. A hole f is formed, and when the piston is desired to be stopped, the brake rod b is rotated to engage the outer peripheral surface of the brake rod with the cam surface formed on the inner periphery of the hole f,
As a result, the driver is stopped.

Further, in the above-mentioned one, as shown in FIG. 7, the brake shoe, that is, the web k provided with the braking surface j is pressed by the disc spring l so that the braking surface j is frictionally engaged with the seal band m. As shown in FIG. 8 or a structure that allows the plunger p to be movable on the movable table o of the rodless cylinder, a brake shoe r that engages with the cylinder tube q is attached to the plunger p, and the plunger p is attached. The disc spring s elastically applies pressure to the cylinder tube side and allows the cylinder to move in the opposite direction against the disc spring so that the pressing force of the disc spring exerts a braking force.

However, in the above device, when the driver or the slide table is stopped in the middle, a twisting moment acts on the end of the brake rod or screw shaft extending along the entire length of the cylinder tube. There is a problem that the stroke of the piston cannot be increased due to the torsional rigidity, and the device has a problem that the braking force is small because the brake shoe is not pushed to the cylinder tube only by the force of the disc spring.

(C) Problem to be Solved by the Invention The present invention is an intermediate stop device for a rodless cylinder, in which an eccentric shaft attached to a movable table expands a force to act on a brake shoe, so that the brake rod is unnecessarily large. This is to generate a large braking force without applying a torsion moment, and thereby to be applicable to a rodless cylinder having a large stroke.

(D) Means for Solving the Problems The present invention includes a cylinder tube whose both ends are closed, and a piston movably provided in the cylinder tube,
A piston yoke that is connected to the piston so as to move together and a part of which is exposed to the outside through the slit of the piston tube, and the operation of the piston is extracted to the outside of the piston tube through the piston yoke. In a device for intermediately stopping the piston used in a rodless cylinder, a pair of guide members extending parallel to each other along the cylinder tube are provided and fixed on both sides of the cylinder tube, and a movable table is attached to the yoke. An eccentric shaft is rotatably attached to the movable table near the guide member, a brake cylinder for rotating the eccentric shaft is provided on the movable table, and a brake piston of the brake cylinder is provided via a brake arm. A brake shoe is attached to the eccentric shaft, the brake shoe engaging with the guide member is attached to the eccentric shaft. The coupling portion between the stone and the brake arm is biased by a spring in the direction in which the brake shoe is pressed toward the guide member, and the eccentric distance between the rotation center of the eccentric shaft and the center of the eccentric portion is set to the brake arm. It is configured to be sufficiently smaller than the distance between the point of action of the brake piston and the eccentric shaft.

(E) Action In the above configuration, when the brake piston of the brake cylinder is moved in one direction by the fluid pressure and the spring force to rotate the eccentric shaft, the action of the eccentric shaft separates the brake shoe from the guide member. Next, when stopping the piston at an arbitrary position, first, when the brake piston of the brake cylinder is operated in the opposite direction to the above with spring force or fluid pressure, the eccentric shaft is rotated in the opposite direction and the brake is applied by the action of the eccentric shaft. The shoe is pressed into engagement with the guide member. Therefore, the braking force acts on the piston connected to the housing via the movable table and the yoke, and the piston stops at a predetermined position.

(F) Example Hereinafter, an example of the present invention will be described with reference to the drawings.

1 to 5, the intermediate stop device 1 of this embodiment is shown together with a rodless cylinder 100 having a known structure. The rodless cylinder 100 is a cylinder tube 101 of a cylinder tube 101 defining a cylinder hole 102 having a non-circular cross section and a slit 103 extending along substantially the entire length.
And a pair of pistons movably and axially separated from each other in the cylinder hole 102 (only half of the intermediate stopping device from the center is shown in cross section in FIG. 1). Only one piston is shown) 106
And a connecting member for connecting the pair of pistons 106, that is, a yoke 110, and a pair of band-shaped sealing members 120 and 121 provided in the opening of the slit 103 of the cylinder tube 101.

The yoke 110 is a base part contained in the cylinder tube 101.
111, a head portion 112 on the outside of the cylinder tube 101 to which a housing of an intermediate stop device, which will be described later, is attached via a mounting plate 118, and a slit 103 of the cylinder tube 101 to extend in and out of the cylinder tube. Connection part for connecting the base part 111 and the head part 112
113, and the cross-sectional shape of the central portion thereof is as shown on the left side in FIG. The axial length L ₁ of the head portion 112 and the connecting portion 113 is the distance between the ends in both pistons 106.
It is smaller than L ₂ . Grooves 114 and 115 extending in the axial direction are formed on the lower surface of the base portion 111 and the upper surface of the head portion, and these grooves communicate with each other on both sides of the connecting portion 113.

Both ends of the sealing members 120 and 121 are cylinder tubes 101.
Seal groove 122 formed inside and outside the slit 103 of
And 123 and fixed to the cylinder tube. The seal member 120 is inside the slit 103, and at the position of the piston 106, the action of the piston causes the seal groove 122.
It is pushed into and extends through the groove 114 at the location of the yoke 110, thereby preventing fluid from leaking from within the cylinder tube 101 through the slit.

Reference numeral 131 denotes a supply / discharge port formed in a port block 130 fixed to the outside of each cover 105, and is a pressure chamber C ₁ limited to both sides of the piston 106 in the cylinder tube 101.
And it is in communication with any of the C _2.

The intermediate stop device 1 includes a movable member 2 fixed to a connecting member, that is, a head portion 112 of a yoke 110, and guide members 3 (3a, 3b) arranged and fixed along both sides of the cylinder tube 101 along the cylinder tube. ) And. The guide member 3 is placed on the upper edge of the base 150 having a substantially U-shaped cross section to which the cylinder tube 101 is fixed, and is fixed to the stage by fixing means such as a set screw.

Cylinder blocks 4 are attached to the movable table 2 at both front and rear ends (right and left ends in FIG. 1). Both ends of each cylinder block 4 (both left and right in FIG. 3)
Includes a protruding portion 41 (41a, 4a) protruding downward to the side of the guide member.
1b) is formed, and a cavity 42 extending vertically is formed at both ends (right end in FIG. 3). The cylinder block 4 is further formed with a cylinder hole 43 extending in the lateral direction (horizontal direction in FIG. 3) above the cavity 42. An eccentric shaft 51 penetrating the cavity 42 is attached to one of the protruding portions 41 of the cylinder block so as to be rotatable substantially parallel to the guide member 3. A brake arm 52 having a bifurcated upper part is fixed to the eccentric shaft 51. A brake piston 53 is movably provided in the cylinder hole 43, and pins 54 are fixed to both sides of the brake piston. Each pin 54 is received in a groove formed in the forked upper end of the brake arm 52, whereby the brake piston 53 and the brake arm 52 are connected. Brake piston 53
Is elastically pressed toward the center line OO of the cylinder block 4 by the spring 55. The eccentric shaft 51, the brake arm 52, the brake piston 53, the pin 54, the spring 55, etc. constitute the brake operating device 5.

A brake shoe 6 is provided in an opening 44 formed on the cylinder tube side of the protrusion 41a so as to be movable in the horizontal direction (see FIG. 3). An elongated hole 61 is formed in the rear portion of the brake shoe 6, and the eccentric portion 51a of the eccentric shaft 51 is received in the hole 61. The center of the eccentric portion is deviated by δ with respect to the portion supported by the cylinder block 4. The extension direction of the hole 61 of the brake shoe 6 and the eccentric shaft 51
In this embodiment, when the brake piston 53 is biased toward the center line OO by the spring 55, the eccentric portion 51a presses the brake shoe 6 toward the guide member 3 side, and When the cylinder 53 moves to the side of the cover 45 fixed to the cylinder block 4, the pressing of the brake shoe 6 is released. The reverse is also possible. Further, the brake shoe 6 and the brake actuating device 5 described above.
Is similarly formed on the other end of the brake block 4, but is not shown for simplification of description. A material having a large friction coefficient may be attached to the engaging surface of the brake shoe 6.

A bearing member 46 is fixed to the projecting portion 41 of the cylinder block 4 at a position facing the guide member 3b and on both sides of the opening 44. Between the bearing member and the guide member 3b, the bearing member has a substantially entire length. A ball 47 rolling inside the V-shaped groove 31 thus formed is provided. The bearing member 46 and the ball
Reference numeral 47 constitutes a plane bearing which cooperates with the guide member to guide the movable table 3 along the guide member.

The cylinder hole 43 of each brake cylinder is formed in the movable table 2 and communicates with the brake port 22 via the fluid passage 21. The brake port 22 is connected to a fluid pressure supply device (not shown) having a known structure, and the fluid pressure supply device selectively supplies fluid pressure.

In the intermediate stop device having the above structure, when the fluid pressure is not supplied into the cylinder hole 43, the brake piston 53 is pressed by the spring 55 toward the center line OO side of the brake block 4, so that the upper end of the brake arm 52 is stopped. Is also pushed toward the center line side and rotates counterclockwise (with the brake arm shown on the right side in FIG. 3), and the eccentric shaft 51 also rotates in the same direction. Therefore, the brake shoe 6 is pressed toward the guide member 3a by the eccentric portion 51a of the eccentric shaft 51, and the brake shoe 6 engages with the guide member. Therefore, the braking force is applied to the movable table 2, and the braking force also acts on the piston 106 connected to the movable table 2 via the connecting member, that is, the yoke 110, and the piston 106 is stopped and held. Similarly, a brake shoe provided on the opposite side of the cylinder block 4 and a brake shoe provided on another cylinder block are engaged with the guide member to apply a brake.

Next time you want to move the piston 106, the brake port 22
A predetermined fluid pressure is supplied into the cylinder hole 43 via. Then, the brake piston 53 moves in the direction away from the center line OO, that is, toward the cover 45 side. Therefore, the pressing force of the brake shoe 6 by the eccentric shaft 51 is released, the brake shoe is separated from the guide member 3, and the braking force on the movable table is released. Therefore, in this state, the cylinder tube
When fluid pressure is alternately supplied to both sides of the piston 106 through the supply / discharge ports 131 formed in the covers 105 fixed to both ends of 101, the piston makes a reciprocating linear motion.

Therefore, if you want to stop the piston at a desired position during the reciprocating motion of the piston, it is possible to quickly discharge the fluid pressure in the cylinder hole of the brake cylinder for the above-mentioned reason. It stops instantly by force.

Although the brake shoe is pressed against the guide member by the force of the spring when the fluid pressure is not supplied to the cylinder hole in the above-mentioned embodiment, the fluid pressure is applied to the cylinder hole by changing the eccentric direction of the eccentric shaft. You may make it press when pressure is supplied. Further, although the movable table and the brake block are fixed separately from each other, they may be integrally formed.

(G) Effect According to the present invention, since the eccentric shaft that transmits the braking force to the brake shoe can be short, the deflection of the eccentric shaft due to the bending moment is small, and the large deflection of the brake rod as in the prior art is prevented. it can. Also, since the pressing force of the spring or cylinder can be expanded and transmitted by the eccentric shaft,
It is possible to exert a large braking force with a small structure.

[Brief description of drawings]

1 is a sectional elevational view showing a part of an embodiment of a rodless cylinder equipped with a center stop device of the present invention, FIG. 2 is a plan view of the device of FIG. 1, and FIG. Fig. 4 is a sectional view taken along line III-III in the drawing, Fig. 4 is a sectional view taken along line IV-IV in Fig. 3, Fig. 5 is a perspective view of a part of the yoke, and Figs. FIG. 8 is a view showing a conventional intermediate stop device for a rodless cylinder. 1: Intermediate stop device, 2: Movable table 3: Guide member, 4: Cylinder block 5: Brake actuating device, 6: Brake shoe 51: Eccentric shaft, 52: Brake arm 53: Brake cylinder

Claims (1)

[Claims] 1. A cylinder tube having both ends closed, a piston movably provided in the cylinder tube, a piston movably connected to the piston, and a part of the piston through a slit of the piston tube. And a piston yoke that is exposed to the outside, and a device for stopping the piston in the middle by using the rodless cylinder that takes out the operation of the piston to the outside of the piston tube through the piston yoke. A pair of guide members extending parallel to each other along the cylinder tube are provided and fixed, a movable table is attached to the yoke, and an eccentric shaft is rotatably attached to the movable table in the vicinity of the guide member. The table is provided with a brake cylinder that rotates the eccentric shaft, and the brake piston of the brake cylinder is braked. A brake shoe is attached to the eccentric shaft via an arm, and a brake shoe that engages with the guide member is attached to the eccentric shaft. The brake shoe connects the guide member to the guide member by a spring. And the eccentric distance between the center of rotation of the eccentric shaft and the center of the eccentric portion is sufficiently smaller than the distance between the point of action of the brake piston on the brake arm and the eccentric shaft. Intermediate stop device for rodless cylinders.