JPH0567835B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a torsion bellows for protecting moving parts of machines, devices, etc.

[Prior Art] Some movable parts of machines and devices rotate within a certain limited rotation angle and must be protected from the external environment. An example of such a sensor is a sensor that detects a moment acting on a predetermined portion of the machine or device.
This sensor must be protected from physical shock, humidity, etc. in order to maintain detection accuracy.

[Problem to be solved by the invention] Currently, this protection relies on sealing means using O-rings, etc., but these sealing means have sliding parts, and the accuracy of the sensor is affected by the hysteresis etc. This has the problem of a significant drop.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a torsion bellows that has no sliding parts and has an extremely small restraining force against twisting.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a system that surrounds one of the coordinate axes and has a predetermined inclination with respect to this axis,
And in the torsion bellows in which ridge lines of concave and convex portions are formed alternately and continuously at both ends in the axial direction,
A triangle formed by the intersection of two adjacent ridge lines and the ends of the two ridge lines on the side opposite to this intersection is an extension line that connects the ends when this triangle is projected in the axial direction. On the other hand, it is characterized in that a perpendicular line drawn from the intersection point is formed so as to substantially touch a circle including the intersection point and each of the terminal ends.

[Operation] When the bellows is twisted between both sides, the end of the ridgeline bends along the line between the adjacent endpoints, and at the same time the intersection of the ridgelines is displaced in the tangential direction of the circle. In this case, since the torsion acts along the circle, the direction of displacement at the above-mentioned intersection coincides with the direction in which the torsion acts, and as a result, the restraining force against the torsion becomes extremely small.

[Examples] The present invention will be described below based on illustrated examples.

FIG. 1 is a side view of a torsion bellows according to a first embodiment of the present invention. 1 shows a hollow torsion bellows formed from a thin metal plate. 1a is a convex ridgeline of the torsion bellows 1, and 1b is a concave ridgeline. 2 is a ring-shaped upper connecting part, and 3 is a ring-shaped lower connecting part. The structure of this torsion bellows will be explained in more detail with reference to FIG.

FIG. 2 is a developed view of the torsion bellows. In the figure, parts that are the same as those shown in FIG. 1 are designated by the same reference numerals. The figure is an exploded view of an arbitrary part of the torsion bellows 1 cut along a line AB parallel to the Z-axis of the coordinate axes shown in FIG. In the figure, for ease of understanding, a plurality of upward arrows are attached to the convex ridge line 1a, and a plurality of downward arrows are attached to the concave ridge line 1b. Each ridge line 1a is inclined at a predetermined angle with respect to the line AB (with respect to the Z axis), and each ridge line b is inclined at another predetermined angle. The ridge lines 1a and 1b are formed alternately, and are connected to each other at connecting portions 2 and 3 via inclined surfaces, which will be described later. 4, 4' indicate opposing inclined surfaces,
The slope 4 slopes upward from right to left in the figure.
The inclined surface 4' is inclined upward from left to right in the figure. Therefore, at the line B-B, the inclined surface 4
The bottom portion of the inclined surface 4' also rises from right to left in the drawing, and the bottom portion of the inclined surface 4' along line A-A also rises from left to right in the drawing. By connecting the lines AB at both ends of such a developed view, the torsion bellows 1 shown in FIG. 1 is constructed.

Figures 3a and 3b are side views showing the operation of the torsion bellows. FIG. 3a shows the state of the torsion bellows 1 in which both ends of the developed view shown in FIG. 2 are simply connected. h is the distance between the lower end of the connecting part 2 and the upper end of the connecting part 3. This torsion bellows 1 has an X axis,
It exhibits an extremely large restraining force against displacement in the Y-axis and Z-axis directions, and against twisting around the X-axis and Y-axis.
However, the restraining force against twisting around the Z axis is extremely small.

FIG. 3b shows the deformation of the torsion bellows 1 when a moment shown by the arrow around the Z axis is applied to the torsion bellows 1. In this way, the torsion bellows 1 easily deforms into a constricted shape in response to the moment.

Here, the reason why this torsion bellows 1 has a weak restraining force against twisting around the Z axis and easily undergoes the deformation shown in FIG. 3b will be discussed with reference to FIGS. 4a and 4b. Now, in Figure 3 a,
The point where one ridgeline 1a joins with the connecting part 2 is E, the point where this ridgeline 1a joins with the connecting part 3 is C, and the ridgeline 1b that is continuous with this ridgeline 1a at the connecting part 2 is the connecting part 3. Let D be the joining point. These points C, D, and E form the slope of triangle CDE.

If we focus only on this triangle CDE and view it from above in Figure 3a, its projection will be as shown in Figure 4a. In Figure 4a, G is the circle including points C, D, and E, that is, the projection of the connecting parts 2 and 3 from above in Figure 3a, and F is the side CD and the perpendicular drawn from point E to side CD. indicates the intersection of From the above explanation, the ridge lines 1a,
1b and the side CD are difficult to bend and therefore maintain a straight line, thereby keeping the triangle CDE flat.

As shown in FIG. 3b, when the torsion bellows 1 is twisted, the triangle CDE moves while bending at the side CD, and the point E moves on the perpendicular line EF. In this case, the perpendicular EF is the circle G (point E of each triangle) as shown in the figure.
is on this circle. ), the direction of movement of point E and the direction of movement of connecting part 2 are the same, so
Triangular CDE can move without resistance while remaining flat. And since this is true for all the triangles constituting the torsion bellows 1, the torsion bellows 1 will eventually be torsionally deformed very easily.

FIG. 4b is a projection view of the triangle CDE in such a shape that the perpendicular EF does not touch the circle G. In this case, when the torsion bellows 1 is twisted, the moving direction of the point E is different from the moving direction of the connecting portion 2, so the movement occurs while distorting the triangle CDE or the connecting portion 2. Triangle CDE or connection part 2
As a result, the torsion bellows 1 will not twist as easily as the one with the conditions shown in FIG.

From the above, in order to cause the torsion bellows 1 to be torsionally deformed very easily, each connecting portion 2,
It can be seen that it is necessary to form the above-mentioned triangle so that the perpendicular line drawn from the vertices of all the triangles connected by the sides in 3 to the sides is approximately tangent to the circle connecting all the vertices.

From the above, in order to cause the torsion bellows 1 to be torsionally deformed very easily, each connecting portion 2,
It can be seen that it is necessary to form the above-mentioned triangle so that the perpendicular line drawn from the vertices of all the triangles connected by the sides in 3 to the sides is approximately tangent to the circle connecting all the vertices.

When such a torsion bellows 1 is applied to a sensor that detects moment, the moment detection part of the sensor is enclosed inside the torsion bellows 1,
Both ends thereof are connected to a connecting part 2 and a connecting part 3. For convenience of explanation, it is assumed that the end of the sensor is connected to the connecting part 3 and fixed. When a moment about the Z-axis acts on the sensor end connected to the connecting portion 3, the torsion bellows 1 is not restrained and twists very easily in response, as shown in FIG. 3b. Therefore, there is no effect on moment detection by the sensor.

As described above, the torsion bellows of this embodiment has no sliding parts and has almost no restraining force against twisting. When this is applied to a sensor that detects a moment, the detection section of the sensor can be protected from the external environment without affecting moment detection in any way.

5 and 6 are side views of a torsion bellows according to a second embodiment of the invention, FIG. 5 showing the untwisted state and FIG. 6 showing the twisted state. In each figure, the same parts as in FIG. 1 are given the same reference numerals. 5 is a torsion bellows that is separate from the torsion bellows 1 and has the same size;
The torsion bellows 1 and the torsion bellows 5 are connected to the connecting part 3
are connected. 5a is a convex ridgeline of the torsion bellows 5, 5b is a concave ridgeline of the torsion bellows 5, and 6 is a lower connecting portion of the torsion bellows 5. As is clear from the figure, each ridgeline 5a, 5b of the torsion bellows 5 corresponds to each ridgeline 1 of the torsion bellows 1.
It has an inclination in the opposite direction to a and 1b.

By the way, as shown in FIGS. 3a and 3b, the height h of the torsion bellows 1 in the untwisted state is the height h'(h'=h-
Δh) and shorten by the dimension Δh. Since this dimension Δh is extremely small, in most cases,
This displacement can be ignored. The structure of this embodiment shown in FIGS. 5 and 6 is used when the above-mentioned dimension Δh cannot be ignored.

That is, as shown in FIG. 6, if the connecting part 6 is fixed and the connecting part 2 is twisted in the direction of arrow M, the torsion bellows 1 will be twisted and its height will be (h - Δh) as described above. Become. However, at the same time, the connecting portion 3 is also twisted in the direction of arrow M, and the torsion bellows 5 is also twisted. In this case, each ridgeline 5 of the torsion bellows 5
a, 5b are respective ridgelines 1a, 1b of the torsion bellows 1
Since the torsion bellows 5 is formed in the opposite direction, the torsion bellows 5 floats by a minute dimension Δh, and its height becomes (h+Δh). Therefore, the connecting part 2
There is no change in the height between the connecting portion 6 and the connecting portion 6.

In this way, in this embodiment, two torsion bellows of the same size but with opposite inclination directions of the ridge lines are connected, so that the same effect as the previous embodiment is achieved, and even in the twisted state, the length of the torsion bellows can be reduced. can be prevented from changing.

FIG. 7 is a partially cutaway side view of a torsion bellows according to a third embodiment of the present invention. In the figure, parts corresponding to those shown in FIG. 5 are denoted by the same reference numerals, and explanations thereof will be omitted. In this embodiment, the torsion bellows 5
is housed inside the torsion bellows 1. Reference numerals 3' and 3'' are connection parts of the ends of the torsion bellows 1 and 5, respectively, and correspond to the connection part 3 shown in FIG. 5. Reference numeral 7 is a connection member that connects the connection parts 3' and 3''.

When a twist is applied in one direction between the connecting part 2 and the connecting part 6, the torsion bellows 1 and 5 both expand by the same amount, and conversely, when a twist is applied in the other direction, the torsion bellows 1 and 5 both expand by the same amount. Shorten only the dimensions.

Therefore, even if twisting is applied, no relative displacement occurs between the connecting portions 2 and 6.

Note that it is obvious that the relationship between the inside and outside of the torsion bellows 1 and the torsion bellows 5 can be reversed.

In this way, in this embodiment, two torsion bellows whose ridge lines are inclined in opposite directions are combined so that one is housed inside the other, so that the same effect as in the second embodiment is achieved, and , the whole can be made smaller.

FIG. 8 is a partially cutaway side view of a sealing device for a moment sensor according to a fourth embodiment of the present invention. In the figure, the same parts as shown in FIG. 7 are denoted by the same reference numerals, and the description thereof will be omitted. Reference numeral 10 denotes a detection section of a moment sensor, which has a lower flange 10a, an upper flange 10b, and a strain-generating section 10c rigidly connected to each of the flanges 10a and 10b. 10d is a strain gauge attached to the strain generating portion 10c, and 10e is a signal line wired to each strain gauge 10d. When a moment acts between the upper flange 10b and the lower flange 10a, the resistance value of the strain gauge 10d changes according to this moment, and this change is extracted as an electric signal by a signal line, and the moment is detected.

11 is a cylindrical metal case, 12 is a detection unit 10
This is a mounting bolt that fixes the lower flange 10a of the case 11 to the case 11. Note that the upper flange 10b of the detection section 10 is welded to the connection section 6. Reference numeral 13 denotes a cover that closes the gap between the connecting portion 2 and the upper end of the case 11, and is welded to the connecting portion 2 and the upper end of the case 11. Reference numeral 14 denotes a terminal portion hermetically fixed to the side wall of the case 11, to which each signal line 10e is connected. In the above configuration, the coupling member 7 is provided over the entire circumference of the coupling portions 3', 3'', and the gap 1 between the torsion bellows 1 and the torsion bellows 5 is
It also has the function of sealing 5.

In the above configuration, a moment acts between the upper flange 10b and the case 11 to which the lower flange 10a is fixed. Therefore, torsion is applied between the connecting part 6 welded to the upper flange 10b and the connecting part 2 welded to the upper end of the case 11 via the cover 13, but there is no restraint against this torsion. The force is extremely small as described above, and the relative displacement between the two connecting parts 2 and 6 is zero as described in the third embodiment. moreover,
In the detection part 10, only the upper flange 10b is exposed, and the other parts are completely sealed.

In this way, in this embodiment, two torsion bellows whose ridge lines are inclined in opposite directions are joined together so that one is housed inside the other, and while this is housed in a case, the torsion bellows on the outside are Since the connecting part of the bellows and the upper end of the case are welded, and the detecting part of the moment sensor is installed between the connecting part of the torsion bellows inside and the bottom of the case, there is no possibility of any hindrance to the operation of the detecting part. Therefore, the detection section can be completely sealed and protected from the external environment.

〔Effect of the invention〕

As described above, in the present invention, the torsion bellows is constructed by forming an uneven ridgeline with a predetermined inclination surrounding one shaft, so that it slides against the torsion applied to both sides of the torsion bellows. This allows the restraining force to be extremely small.

[Brief explanation of the drawing]

Fig. 1 is a side view of the torsion bellows according to the first embodiment of the present invention, Fig. 2 is a developed view of the torsion bellows shown in Fig. 1, and Figs. 3a and b are side views illustrating the operation of the torsion bellows. Figures 4a and 4b are principle diagrams of the operation of the torsion bellows, Figures 5 and 6 are side views of the torsion bellows according to the second embodiment of the present invention, and Figure 7 is the third embodiment of the torsion bellows of the present invention. FIG. 8 is a partially cutaway side view of the torsion bellows according to the fourth embodiment of the present invention, and FIG. 8 is a partially cutaway side view of a sealing device for a moment sensor according to the fourth embodiment of the present invention. 1, 5...Torsion bellows, 1a, 1b...Ridge line, 2, 3, 3', 3'', 6...Connection part, 4...Slope, 7...Connecting member, 10...Detection part, 11... …
Case.

Claims (1)

[Claims] 1. In a torsion bellows that surrounds one of the coordinate axes, has a predetermined inclination with respect to this axis, and has concave and convex ridge lines that alternately continue at both ends in the axial direction, adjacent A triangle formed by the intersection of the two ridge lines and the ends of the two ridge lines on the side opposite to this intersection, with respect to the extension line connecting the ends when this triangle is projected in the axial direction. A torsion bellows characterized in that a perpendicular line drawn from the intersection point is formed so as to substantially touch a circle including the intersection point and each of the terminal ends. 2. The torsion bellows according to claim 1, wherein the torsion bellows is comprised of a first bellows part and a second bellows part whose directions of inclination are opposite to each other. 3. The torsion bellows according to claim 2, wherein one of the first bellows part and the second bellows part is housed in the other.