JPH0351923B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a fluid pressure cylinder that uses a brake to provide a cushion function. The present invention relates to a hydraulic cylinder equipped with a brake.

[Conventional technology]

At the stroke end of the cylinder, a cushion ring provided on the piston rod is fitted into a cushion packing provided on the cylinder side, thereby temporarily sealing the discharged fluid in the pressure chamber of the cylinder and exerting a cushioning action. For example, the hydraulic cylinder made by Utility Model 101006
As shown in the publication, this is already known.

However, in the above-mentioned known fluid pressure cylinder having such a cushion mechanism, the cushion pressure confined in the pressure chamber by the cushion mechanism near the end of the stroke of the piston provides a buffering force to the piston, resulting in a large load. When the inertial force of the piston becomes larger than the buffering force caused by the cushion pressure, the buffering force to stop the piston is insufficient, and there is a risk that the piston will collide at the end of its stroke.

[Problem that the invention seeks to solve]

The present invention solves the problem of using the cushion pressure generated in the cushion mechanism as a buffering force for stopping the piston, and applying a braking force to the piston rod by the cushion pressure, thereby reliably stopping the piston at the end of the stroke. This is an issue that should be addressed.

[Means for solving problems]

In the present invention, at the stroke end of the cylinder,
In a fluid pressure cylinder in which a cushion ring provided on a piston rod is fitted into a cushion packing provided on the cylinder side, discharged fluid is temporarily confined in a pressure chamber of the cylinder to exert a cushion action. The above problem is solved by providing a brake unit having a brake piston operated by fluid contained in the pressure chamber and a brake shoe that presses against the piston rod by the operation of the brake piston.

[Effect]

Supply high pressure air to one pressure chamber of the cylinder,
When the air in the other pressure chamber is discharged, the piston slides, and near the end of the stroke, the cushion ring provided on the piston rod fits into the cushion packing, temporarily sealing the pressure chamber and reducing the pressure. The rise in pressure in the chamber creates a cushion pressure, which exerts a damping force on the piston.

Also, the brake piston slides and presses the brake shoe due to the cushion pressure, so the brake shoe comes into pressure contact with the piston rod, causing the piston to absorb the buffering force due to the cushion pressure and the braking force due to the brake shoe. Both act;
To surely stop without colliding at the end of a stroke.

〔Example〕

1 and 2 show the structure on the rod side and the structure on the head side in the first embodiment of the present invention,
The cylinder 1 is equipped with brake units 7, 7 on both sides of the cylinder tube 2, in which a head cover 3, a rod cover 4, and brake covers 5, 5 are integrated with mounting bolts 6, . It is constructed by integrally connecting both ends of the cylinder tube 2 with tie rods (not shown).

Brake chambers 8 are formed in the brake units 7 on the rod side and the head side, respectively, and inside the covers 5, 5 that constitute the brake chambers 8,
A cylinder portion 12 is formed in the axial direction of the piston rod, and a through hole 13 having a smaller diameter than the cylinder portion 12 and communicating therewith is provided on the cylinder tube 2 side.

On the other hand, on both sides of the piston 9 sliding inside the cylinder tube 2, cushion rings 14, 14 are formed by enlarging the diameter of the piston rod 10.
is provided.

The brake piston 15, which is fitted airtightly and slidably into the cylinder portion 12, has a recess 16 on the brake chamber 8 side and a gap 17 on the inner peripheral surface of the through hole 13 on the brake cover 5 side. The inner surface of the recess 16 is formed with a cam surface 19 having a smaller diameter on the cylinder tube 2 side.
A ring-shaped cushion packing 2 is formed in the stepped part that is formed to have a larger diameter than 0, and is provided around the inside of the center hole.
0 is fitted, and the cushion packing 2
0 constitutes a cushion mechanism 11 in the pressure chamber 21 of the cylinder 1 with the cushion ring 14 which is tightly fitted thereto.

Furthermore, the covers 3 and 4 of the brake piston 15
The release ring 23 provided opposite to the side end portion is
A brake spring 27 made of a deformed wire interposed between the covers 3 and 4 constantly urges the brake piston 15 in the return direction.

On the rod side of the cylinder, there are rod holes 2 in the bottom wall of the rod cover 4, as shown in FIG.
The piston rod 10 is guided out of the brake chamber through the cylindrical portion 18 of the brake piston 15 and the rod hole 28 in an airtight manner. On the head side of the cylinder, as shown in FIG. 2, a piston rod 10 passes through the cylindrical portion 18 of the brake piston 15 described above, and its tip is loosely inserted into the head cover 3.

Inside the head cover 3 and rod cover 4, an annular bearing mounting plate 32 is fixed with mounting bolts (not shown), and brake arms 34,...
The brake arm 34 is made swingable by having a sphere 33 attached to the base end thereof with a bolt 36 rotatably supported by spherical bearings 35 provided on the mounting plate 32.

The brake arms 34, . The brake shoe 38 is made of a metallic material made of sintered metal powder, a cermet made of sintered magnetic material and metal powder, or the like.

Furthermore, ports 39 are provided in the covers 3 and 4 for supplying and discharging high pressure air to and from the pressure chamber 21 through the brake chamber 8.
is opened, and on the other hand, brake cover 5,5
A communication hole 40 is formed in the brake chamber 8 to communicate the gap 17 with the brake chamber 8, and the communication hole 40 is provided with a cushion valve 41 whose flow rate can be adjusted by a throttle.

In FIG. 1, reference numeral 43 is a high-pressure air source, 44 is an electromagnetic switching valve that alternately supplies and discharges high-pressure air to and from the ports 39 on the head side and the rod side, and 45, 45 are the electromagnetic switching valve 44 and the ports 39, 39. This is a speed controller installed in the air supply/discharge pipes 46, 47 on the head side and rod side between the two.

Next, the operation of the first embodiment will be explained.

1 and 2 show that the switching valve 44 controls the head side supply/discharge pipe 46, the port 39, and the brake chamber 8.
High pressure air is supplied to the pressure chamber 21 on the head side through between the cylindrical portion 18 and the piston rod 10, and the air in the pressure chamber 21 on the rod side is transferred to the cylindrical portion 18 on the rod side.
and the piston rod 10, the brake chamber 8,
The piston 9 is opened to the atmosphere through the port 39, the supply/discharge pipe 47, and the switching valve 44, and the piston 9 slides to the left in FIGS. 1 and 2 by the high pressure air supplied to the pressure chamber 21 on the head side. Indicates a moving state.

When the rod-side cushion ring 14 fits into the cushion packing 20 provided on the brake piston 15 due to leftward sliding of the piston 9, the rod-side pressure chamber 21 is sealed. Its internal pressure rises rapidly. This pressure chamber 2
The internal pressure of piston 9 is defined as the cushion pressure P.
At the same time, it acts on the side surface of the pressure chamber 21 of the brake piston 15 through the gap 17 on the outer periphery of the cylindrical portion 18 of the brake piston 15, and slides the brake piston 15 against the biasing force of the brake spring 27. Since the brake piston 15 is moved, the cam surface 19 of the brake piston 15 moves the brake arm 34, the roller 37 at the tip, toward the center in the radial direction,
As a result, the brake shoes 38, ... come into pressure contact with the outer peripheral surface of the piston rod 10, and the piston rod 1
A braking force f is applied to the piston 9 to stop the piston 9 without colliding with the brake cover 5.

On the other hand, the pressure air that has flowed into the side surface of the pressure chamber 21 of the brake piston 15 passes through the communication hole 40 and the cushion valve 41 and is gradually released into the brake chamber 8 on the rod side. When the force of the brake piston 15 becomes smaller than the force of the brake spring 27, the brake piston 15 returns to its original position by the force of the brake spring 27, ....
The braking action by the brake shoe 38 is released.

The above-mentioned cushion pressure P by the cushion mechanism 11 and the magnitude of the braking force f by the brake shoe 38 can be adjusted by changing the throttle amount of the cushion valve 41, as shown in FIG. When the opening of the throttle of the cushion valve 41 is reduced, the pressure P and the braking force f increase.
Increasing the aperture opening will reduce these.

When the switching valve 44 is switched from the state shown in Fig. 1 to supply high-pressure air from the high-pressure air source to the pressure chamber 21 on the rod side and open the head-side pressure chamber 21 to the atmosphere, the high-pressure air is supplied to and discharged from the rod side. It is supplied to the pressure chamber 21 on the rod side through the pipe 47, port 39, and brake chamber 8, and the braking force from the brake shoes 38, . . . is released, so the piston 9 slides to the right without any hindrance. .

The cushioning action and braking action on the head side near the end of the rightward stroke of the piston are the same as on the rod side, so a detailed explanation will be omitted.

FIG. 4 shows a second embodiment of the invention;
The brake shoe 50 in the embodiment includes a contact portion 51 that contacts the piston rod 10, and a corresponding contact portion 5.
Air is supplied and discharged from the port 39 to the pressure chamber 21 through the arms 52, . . .

In this second embodiment, the brake piston 15 directly presses the brake shoe 50, and the contact portion 51 of the brake shoe 50 is pushed between the cylindrical portion 4a of the rod cover 4 and the piston rod 10.
This embodiment is the same as the first embodiment except that a braking force is applied to the piston rod 10.

In addition, in the first and second embodiments, the brake piston 15 and the brake shoes 38, 50 are provided on both the head side and the rod side of the cylinder, but they are provided only on either the head side or the rod side. You can also do that.

FIG. 5 shows a third embodiment of the present invention;
In the embodiment, the brake piston 55 is provided with a communication hole 56 that communicates the brake chamber 8 and the pressure chamber 21, and air supplied and discharged from the port 39 flows through the communication hole 5.
6, the shape of the brake shoe 50 is divided into a plurality of parts,
The operation is the same as in the second embodiment except that a return spring 57 is interposed between the brake shoe 50 and the bottom wall of the rod cover 4.
The second embodiment is the same as the second embodiment except that the brake piston 55 and the brake piston 55 are returned to their original positions.

〔Effect of the invention〕

In the present invention, near the end of the stroke of the piston, the piston receives a buffering force due to the cushion pressure, and the brake piston, which slides due to the cushion pressure, presses the brake shoe against the piston rod, and the braking force due to the brake shoe is applied. is applied to the piston rod, so even if the inertia of the piston is large, the piston can be reliably stopped at the end of its stroke.

In addition, since the braking force is applied by the brake shoe mentioned above using the cushion pressure generated by the cushion mechanism, not only is there no need for special piping to operate the brake shoe, but also the brake force is applied at the end of the stroke of the piston. The braking force can be reliably applied.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional front view showing the structure on the rod side of the first embodiment of the present invention, Fig. 2 is a longitudinal sectional front view showing the structure on the head side of the same, Fig. 3 is the cushion pressure and brake by the cushion valve. FIG. 4 is a partially omitted longitudinal sectional front view of the second embodiment of the present invention, and FIG. 5 is a longitudinal sectional front view of the third embodiment of the present invention. . 1... Cylinder, 7... Brake unit, 1
0... Piston rod, 14... Cushion ring, 15, 55... Brake piston, 20...
Cushion packing, 21...pressure chamber, 38,
50...Brake use.

Claims (1)

[Claims] 1 At the stroke end of the cylinder, a cushion ring provided on the piston rod is fitted into a cushion packing provided on the cylinder side, thereby temporarily sealing the discharged fluid in the pressure chamber of the cylinder and exerting a cushioning action. A fluid pressure cylinder characterized in that it is equipped with a brake unit having a brake piston operated by fluid confined in the pressure chamber and a brake shoe that presses against the piston rod by the operation of the brake piston. .