JPH0130643Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an improvement of a cylinder with a return spring.

[Prior art]

As shown in FIG. 1, this type of cylinder with a return spring generally includes an outer cylinder 10 having a pressure inlet 11 on one side, and a rod 20 movably provided in the outer cylinder 10 along its axis. , an inner cylinder 30 attached to the pressure hole 11 side of this rod 20
A rolling diaphragm 40 is attached to form a pressurizing chamber P between the outer periphery of the inner cylinder 30 and the inner periphery of the outer cylinder 10, and the rod 20 is constantly pressurized to the pressure hole 11 side. When air or liquid (hereinafter referred to as fluid) is pressurized into the pressurizing chamber P from the pressure input hole 11, the pressure of this fluid causes the inner cylinder 30 and the diaphragm 40 to move to the non-pressure receiving side. When the rod 20 is moved against the repulsive force of the return spring 50 and the press-in of the fluid is stopped, the rod 20 is moved by the repulsive force of the return spring 50.
can be returned to its old position.

And the effective diameter of the diaphragm 40 is D ₀ ,
The pressure to the pressurizing chamber P is P ₀ , and the return spring 5
0's spring constant is k, the moving stroke of rod 20 is S,
Net pressing force (net output) obtained from Rod 20
Assuming that F is the net pressing force F, this net pressing force F can be expressed by the following formula.

F=π/4D ² ₀ ×P ₀ −k×S (However, the resistance due to movement is small and is ignored.) As can be seen from this equation, in the conventional cylinder with a return spring, the pressure P ₀ to the pressurizing chamber P is If it is constant, the greater the moving distance S of the rod 20, that is, the greater the amount of movement of the rod 20, the greater the reaction force of the return spring 50.
When comparing the net pressing force F at the beginning and the net pressing force F at the end of the moving stroke S of the rod 20, there is a drawback that the net pressing force F at the end decreases.

In this way, if the net pressing force F at the beginning and end of the moving stroke S of the rod 20 is different, for example, if this cylinder with a return spring is used in a polishing device for a rolling roll A as shown in FIG. As the grinding wheel B wears out and the rod 20 moves toward the rolling roll A, the reaction force of the return spring 50 increases, and the pressing force of the grinding wheel B against the rolling roll A decreases. Therefore, conventionally, in order to keep the pressing force of the grinding wheel B against the rolling roll A constant, it was necessary to install a regulator R as shown in the figure and to adjust it frequently.

[Purpose of invention]

The present invention was achieved as a result of studies to solve the above-mentioned problems.

Therefore, an object of the present invention is to provide a cylinder with a return spring that can maintain a constant net pushing force, that is, a net output of the rod, regardless of the movement stroke of the rod, even if the pressure in the pressurizing chamber is kept constant. It's about doing.

[Structure of the idea]

In other words, the present invention consists of an outer cylinder provided with one pressure entry hole, a rod provided on the outer cylinder so as to be movable along its axis, an inner cylinder attached to the pressure entry hole side of the rod, and the rod. It consists of a rolling diaphragm attached to form a pressurizing chamber between the outer periphery of the inner cylinder and the inner periphery of the outer cylinder, and a return spring that constantly pressurizes the rod toward the pressure hole. The gist of the cylinder is a cylinder with a return spring formed so that the distance between the outer periphery of the rod and the inner periphery of the outer cylinder gradually increases in the direction of the pressurizing stroke of the rod.

The means for forming the distance between the outer periphery of the inner cylinder and the inner periphery of the outer cylinder to gradually increase in the direction of the pressurizing stroke of the rod includes, for example, forming the outer cylinder in a shape that enlarges the inner diameter. This can be realized by forming the inner cylinder into a shape that reduces the outer diameter, or by using both of the above shapes in combination.

〔Example〕

Hereinafter, the present invention will be explained in detail by way of examples with reference to the drawings.

FIGS. 3a and 3b show a cylinder with a return spring according to an embodiment of the present invention, where a is an explanatory cross-sectional view showing the state before the working fluid is pressurized, and FIG. 3b is an explanatory cross-sectional view showing the cylinder after the working fluid is pressurized.

In the figure, E is a cylinder with a return spring according to an embodiment of the present invention, and one side has an inlet hole 11.
an outer cylinder 10 provided with an outer cylinder 10, a rod 20 provided movably along the axis of the outer cylinder 10, and an inner cylinder 30 attached to the pressure hole 11 side of the rod 20.
, a rolling diaphragm 40 attached to form a pressurizing chamber P between the outer periphery of the inner cylinder 30 and the inner periphery of the outer cylinder 10, and a return that constantly pressurizes the rod 20 toward the pressure hole 11 side. spring 5
0, and the shape of the outer cylinder 10 and/or the inner cylinder 30 is formed so that the effective diameter of the diaphragm 40 can be increased in accordance with the pressure stroke of the rod 20.

To further explain this structure in detail, in this embodiment, the outer cylinder 10 is divided into two from approximately the center into a left side outer cylinder 10a and a right side outer cylinder 10b, as shown in the figure. Filling pressure hole 1
1 is provided, and the right outer cylinder 10b is provided with a rod 20 so as to be movable along its axis as described above.

As shown in the figure, the inner cylinder 30 attached to the pressure hole 11 side of the rod 20 is formed so that its outer diameter gradually decreases toward the non-pressure receiving side 30b. And the pressure receiving side 3 of this rod 20
0a is the small diameter side 40a of the diaphragm 40.
is integrally attached by a holding plate 31, and the large diameter side 40b of this diaphragm 40 is integrally attached between the left outer cylinder 10a and the right outer cylinder 10b of the outer cylinder 10 by a connecting fitting 10c. is installed.

Therefore, when fluid is pressurized into the pressurizing chamber P from the pressure inlet 11, the pressure of this fluid causes the inner cylinder 30 to
The diaphragm 40 is pressed toward the non-pressure receiving side 30b, and the rod 20 can be moved against the elastic force of the return spring 50. Moreover, when the rod 20 is moved, the effective diameter of the diaphragm 40 is It can be gradually increased in size in response to changes in the outer diameter of the cylinder 30. As a result, even if the pressure P ₀ in the pressurizing chamber P is kept constant, the net pressing force of the rod 20, that is, the net output, can be kept constant at all times, regardless of the movement stroke of the rod 20.

In this embodiment, in order to always keep the net pressing force, that is, the net output, of the rod 20 constant regardless of the movement stroke of the rod 20, the outer diameter of the inner cylinder 30 is set to the non-pressure receiving side 30b as described above. The outer diameter of the inner cylinder 30 was formed to be constant, and the inner diameter of the outer cylinder 10 was formed to gradually become larger as it reached the non-pressure receiving side 10b. Alternatively, the outer diameter of the inner cylinder 30 may be formed to gradually become smaller as it approaches the non-pressure receiving side 30b, and the inner diameter of the outer cylinder 10 may be formed as gradually larger as it approaches the non-pressure receiving side 10b. It may be formed into

Expressing this using a formula, in the above-mentioned formula F=π/4D ² ₀ ×P ₀ −k×S, the effective diameter can be increased by an amount corresponding to the spring reaction force, k×S, due to the increase in stroke. It is.

F ₀ = π/4D ² ₀ ×P ₀ −kx ₀ F=π/4D ² ×P ₀ −K(x−x ₀ )Here, the conditions for F ₀ =F are: If D is set to be, the reaction force of the return spring against the piston stroke is canceled, and it becomes possible to always obtain a constant net output.

Here, F ₀ : Net output at piston stroke x ₀ F: Net output at piston stroke x k: Return spring constant x ₀ , x: Piston stroke D ₀ : Diaphragm effective diameter at piston stroke x ₀ D: Diaphragm at piston stroke x Effective diameter _P0 : Supply pressure.

[Effects of the invention] Since the present invention is constructed as described above, when air or fluid is forced into the pressurized chamber through the pressure input hole, the inner cylinder and diaphragm are pressed toward the non-pressure receiving side by the pressure of this fluid. , the rod can be moved against the elastic force of the return spring, and when the rod is moved, the effective diameter of the diaphragm is gradually increased in accordance with the change in the shape of the outer cylinder and/or the inner cylinder. can do. As a result, even if the pressure inside the pressurized chamber is kept constant,
The net pressing force of the rod, that is, the net output, can be kept constant regardless of the rod's travel stroke.

Therefore, there is no need to take into account the reduction in net output due to the return spring, so the size can be reduced compared to the conventional one, and there is no need to frequently adjust the pressure of the supply fluid as in the conventional one.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional explanatory view showing an example of a conventional cylinder with a return spring, FIG. FIG. 3A is a cross-sectional explanatory view showing the cylinder before the working fluid is press-fitted, and b is a cross-sectional explanatory view showing the cylinder after the working fluid is press-fitted. 10... Outer cylinder, 11... Pressure hole provided on one side of the outer cylinder, 20... Rod, 30... Inner cylinder, 40...
Rolling diaphragm, 50... Return spring, P... Pressurizing chamber.

Claims (1)

[Scope of utility model registration request] An outer cylinder provided with one pressure inlet hole, a rod provided movably along the axis of the outer cylinder, an inner cylinder attached to the pressure inlet side of the rod, and an outer periphery of the inner cylinder. A rolling diaphragm attached to form a pressurized chamber between the inner periphery of the outer cylinder,
The rod is comprised of a return spring that constantly pressurizes the rod toward the pressure hole, and the distance between the outer periphery of the inner cylinder and the inner periphery of the outer cylinder is formed to gradually increase in the direction of the pressurizing stroke of the rod. A cylinder with a return spring characterized by: