JPS60146960A - Fixing structure of rolling diaphragm - Google Patents

Abstract

PURPOSE:To reduce the extending and contracting rates of rolling diaphragm by tapering the inner wall side of housing and the side wall side of piston in the direction to reduce the expansion factor. CONSTITUTION:A rolling diaphragm 16 is fixed between the inner wall of housing 11 and the side wall of piston 14 then the housing and the facing surface of piston 14 are tapered to maintain approximately same inclination angles theta1, theta2. Consequently, the expansion factor of rolling diaphragm can be reduced by 2lxpi sintheta. (Here, lx is the slack length of rolling diaphragm 16 between A and B.)

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to actuators that operate under positive pressure or negative pressure, etc.
It has a rolling diaphragm structure to ensure sealing between the housing and the side wall of the piston that moves inside the housing.

[Conventional example] An example of an actuator that operates with conventional positive pressure or negative pressure? @1
As shown in the figure. That is, in the figure, an inlet 2 and eight outlet ports for fluid are provided at one end of a housing 1, and four pistons are fitted into the housing 1 so as to be movable therein. A rod 5 is attached to approximately the center of the piston 4 and extends outward to connect with a driven body (not shown). l! A rolling diaphragm 6 is layered between the side wall of the Ic piston 4 and the inner wall of the housing 1 to maintain airtightness.

The rolling diaphragm is fixed to the inner wall of the housing 1, and the approximately central force 1 is fixed to the rod 5 and the piston 4 to clamp the rod 5 and the piston 4. Is the rolling diaphragm 6 on the side wall of the piston 4 and the inner wall surface of the housing 1? The roof consists of a rotating shaft. In the actuator shown in Fig. 1, a similar rolling diaphragm 7 is used.
is one end of the housing 1 m 1 a Toviston rod 5
It is also inserted between the piston rod 5 and is configured to roll between the two when the piston rod 5 moves. Reference numeral 8 denotes a spring that is fitted into the housing 1 and has a force that pushes the piston 4 back against fluid pressure (towards the left in the figure).

As described above, the rolling diaphragm 6.7 formed in the housing 1 is intended to seal the space between the positive pressure chamber (or negative pressure chamber) and the atmospheric pressure chamber, during transfer due to the movement of the piston 4. The motion resistance is very small, and there is no need for lubrication, which has the advantage of reducing friction loss and hypothermia loss! are doing.

In this way, by using the rolling diaphragm fl,7t, smooth operability can be obtained when the actuator is operated, so the above-mentioned rolling diaphragm is used in the actuator that operates with positive pressure or negative pressure. It is often used. r In the above conventional device, when compressed air or other fluid is introduced from the fluid inlet 2, the piston 4
moves to the right against the elastic force of the spring 8, and the rod δ is fully pulled and driven to fully operate the intended driven body. On the other hand, as shown in Figure 2, which is an enlarged view of the L part in Figure 1, is there a constant clearance between the side wall of the piston 4 and the inner wall of the housing 1? Generally, the rolling diaphragm 6, which rolls between the two, has substantially parallel opposing surfaces, so that the external stress to which the diaphragm is subjected, quasi-n, depends on the position IC of the rolling diaphragm 6. The stress held by the rubber body is different. This is because when comparing the case where the contact surface of the rolling diaphragm 6 is located on the surface of the piston 40 and the case where the contact surface is located on the inner wall surface of the housing 1, the latter case is located from the center position of the rod 5. Since the elongation X≠1 increases by the distance force I that is longer, this results in the difference in stress as described above. Now, twice the distance from the center position O of the piston 4 to the side wall of the piston 4, the piston outer diameter t"d (1
+ Similarly, twice the distance from the center fO of the piston 4 to the inner wall of the housing 1 - (2) Housing inner diameter.

Then, when the rolling diaphragm 6 is located on the side of the piston 4, the director /I matches the circumference of the piston, so /, = πd0 (11) The circumference l when the rolling diaphragm 6 is located on the inner wall of the housing 1 matches the inner radius of the housing 1, so 1t=trD6・mountain・・(
21 When the diaphragm-71 rolls from the regular wall of the piston 4 toward the inner wall of the housing, △l=β, -β, =π(Do-a.) ・・・・・・(
3) That is, the rolling diaphragm is extended by a length n indicated by Δ. Above (shown in equation 31 - Jfi △l is the diameter D0 and d. As the difference becomes larger,
r,! ! As the clearance between the zero piston 4 and the housing 1 increases, it increases, and within the time period when the actuator is fully activated, the extension and contraction operations of 61 minutes are constantly performed repeatedly. The above-mentioned elongation and shortening operations are transmitted as stress fluctuations to the material constituting the rolling diaphragm 6, which is usually an NBR-based rubber body with a base fabric, which accelerates the deterioration of this rubber body, resulting in fly-spots that shorten the entire life of the device. In order to minimize stretching and aging of the rubber body, it is possible to install the rolling diaphragm 6 on the inner wall surface of the housing 1 in an unstretched state when the rolling diaphragm 6 is installed. It is thought that the above-mentioned cap point fE can be solved by eliminating the elongation of The problem is that the force acts and the rubber body bends, causing a waving phenomenon and accelerating the deterioration of the rubber body.

[Purpose of the invention]

The present invention solves the above problems that occur in the conventional rolling diaphragm mounting structure, and reduces the extension and retraction of the rolling diaphragm during reciprocating movement of the piston. This is intended to improve the reliability and performance of the device.

[Summary of the invention]

In order to quickly achieve the above object, the present invention provides a taber r in a direction that reduces the stretch cage of the diaphragm that moves while rolling against the inner wall of the housing of the side wall structure 9 of the piston when the piston moves in one direction. The main objective is to obtain a device provided on both the inner wall side of the housing and the side wall side of the piston.

〔Example〕

Embodiments of the present invention will be described below based on all the drawings. That is, FIG. 8 shows a main part of the rolling diaphragm mounting structure according to the present invention, and is a sectional view of a portion similar to the structure shown in FIG. 2. In the figure, 11 indicates a housing, and a piston 1 facing the inner wall of the housing 11
In order to install the rolling diaphragm 16 between the side wall of the housing 11 and the piston 14, approximately the same angle (lff9I+angle θ1.θ,
It is characterized by the provision of a taber 7 which holds the whole body. , and FIG. 4, which is drawn under the same constraints as FIG. 8, will be fully explained below. rolling diaphragm 16
When is slack between A and 3, let the slack length be lX, and let θI = 02 = θ, then the slack length - JA.

is 1x = AB = AC - (4) 2 of the distance from the center position 1i0 of the piston 14 to BA-j
@id, Similarly, if the distance from the center position of the piston 14 to point A is 2 @ k D, then the rolling diaphragm 1B is connected to the side wall work 9 housing 11 of the piston 14.
The amount of elongation Δ11 when rolling against the inner wall is Δ73. :=(
D, -11z s tnθ×2)π-d1 π==(
D, -d,) yr-21zyr sinθ -・-
・It becomes +51.

On the other hand, if the equation 31 is used as described above, the extension Δ of a similar diaphragm when the side wall of the piston is parallel to the inner wall of the housing is Δ l 2 π (vo ao) ...... (:
It can be expressed as a digraph, which is D0kiDI+dOkid.

When considered as
-Δl, Ki2/xπstn B...161. As a result, the elongation Δj of the rolling diaphragm when the tapers as disclosed in the present invention are set on both the side wall of the piston and the inner wall of the housing.

211zrr s i
In other words, the process of attaching a taper to the housing 11 and piston 14 is 90-ring diaphragm extension 1.
It can be reduced by 2iXyrstnθ. The slack length ix is increased by engineering, and the taper angle θ is
On the other hand, by making the rolling diaphragm larger, it is possible to reduce the stress on the rubber body by making the extension system and cylindrical body smaller when the rolling diaphragm rolls.

The operation of the above-mentioned rolling diaphragm with door bar is further analyzed based on FIG. 6 as follows.

In the figure, ACB is the initial slack length C/X,
Let AX=BD. 6 is assumed to be a distance kAv, and when the piston moves, it is assumed that the contact A of the rolling diaphragm housing 114U moves to the contact A' on the piston side. The moving distance of the piston i[11 at this time is 2AV.

Because EA′-=AB, ACB=:EA′ is,
The membrane length that has moved by 4 is FgACB=FEAB', and the contact point A will eventually move to point A1 along with the 4-rib of 2AV of the piston. On the other hand, when the distance between the walls is set to 10, the diaphragm extension Δi' is the sag between AB and tlx, as mentioned above, △/! ':= yt (DI d+) 2% sinθ
It becomes π. In addition, when Δl': O, π(DI-stick)=l? xstnOπ, and if the film length of It x = AO' is an,
This eliminates the stretching and shortening phenomena of the rolling diaphragm during transfer.

〔Effect of the invention〕

Above, we have carried out detailed structural and theoretical analyzes regarding the mounting structure of the rolling diaphragm according to the present invention.
If the present invention is used, the housing Pi? When the rolling diaphragm attached to the piston and the housing NVCFE, which move while maintaining a constant clearance, rolls, the extension and shortening of the rolling diaphragm can be reduced by 2 by using the above-described technology .The stress applied to the rubber body that makes up the rolling diaphragm is reduced, and even if the actuator continues to operate continuously due to repeated use, the rubber body suffers less deterioration, extending its lifespan and improving the reliability of the equipment. It has the advantage of being flexible, and is particularly effective when placed inside an actuator that operates under positive pressure or negative pressure.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an example of a conventional actuator, and FIG. 2 is an enlarged cross-sectional view of the annular metal shown in FIG. 1. Fig. 3a shows one embodiment of the present invention, and is a cross-sectional view of a portion similar to the structure shown in Fig. 2, and Figs. 4 and 5 show the structure of Fig. 8 with equal constraints. FIG. 11...Housing, 14...Piston, 16...
・Rolling diaphragm. 2 people outside

Claims (1)

[Claims] +11 A piston is inserted into the housing so that it can move freely, and the piston is interposed between the side wall of the piston and the inner wall of the housing, one end is fixed to the inner wall of the housing, and the other end is fixed to the piston side. Piston movement! When the piston moves in one direction, in an electrical appliance manufacturing machine equipped with a rolling diaphragm attached to a mechanism that completely rolls between the side wall of the piston and the inner wall of the connecting ring at the time of a, and completely maintains the airtightness between the two, when the piston moves in one direction, A rolling diaphragm, characterized in that it is provided on both the inner wall of the housing and the side wall of the piston. Care structure.