JP2000087920A - Expansion/retraction position detecting mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To display an expansion/retraction state of a hydraulic cylinder with an accurate numerical value to improve flexibility of the hydraulic cylinder by finishing an inner periphery so as to be a sliding surface while allowing insertion of a tip of a sensor rod to a passenger cabin and having a cylinder set to be a cylindrical shape. SOLUTION: A passenger cabin B to which a tip of a sensor rod 1 is inserted in a shaft part of a rod body R has a cylinder 4 arranged in a fitted state. The cylinder 4 has a cylindrical part 4a fitted to the passenger cabin B and having an inner periphery to which a tip of the sensor rod 1 is inserted, and a mounting part 4b of a flange shape fixed to a piston R1 at a base end of the rod body R connected to the cylindrical part 4a. The cylindrical part 4a has an inner periphery which is finished so as to be a sliding surface, and a tip of a sensor rod holding member 3 integrally holding the sensor rod 1 is inserted to the cylindrical part 4a. Accordingly, an operation of a stroke sensor is secured and flexibility of a hydraulic cylinder is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a structure for detecting a telescopic position in a hydraulic cylinder.

[0002]

2. Description of the Related Art For example, in the case of a hydraulic cylinder installed in a basement or the like and expanded and contracted by remote control or the like, the expansion and contraction state can be accurately displayed numerically even if the expansion and contraction state cannot be visually recognized directly. May be required.

In order to meet such demands, various types of extension / contraction detection structures for hydraulic cylinders have been proposed. Among them, the extension / contraction position built into a hydraulic cylinder to be a built-in type is disclosed. The detection structure is as follows.

[0004] That is, as shown in FIG. 6, this conventional example of a telescopic position detecting structure has internal hydraulic chambers A1 and A2.
And a cylinder body C that communicates with a hydraulic supply / discharge source P (not shown), which is disposed outside, and which is inserted into the cylinder body C so that the base end thereof can protrude and retract into the cylinder body C. It is supposed to be built in a hydraulic cylinder composed of a rod body R that partitions the hydraulic chambers A1 and A2.

[0005] Incidentally, the hydraulic chambers A1 and A2 in the above-mentioned cylinder body C are defined by a piston portion R1 which is a base end of the rod body R.

On the other hand, in the telescopic position detecting structure, the base end side is held by a bottom portion C1 which is the base end portion of the cylinder body C, and the front end side is present in a chamber B formed in the axial center of the rod body R in a long hole shape. And the above-mentioned chamber B
Has a magnet 2 adjacent to the sensor rod 1 at the axis of the piston portion R1 of the rod body R having an opening, that is, a magnet 2 formed in a tubular shape and through which the sensor rod 1 is inserted as shown in the figure. It has become.

By the way, the sensor rod 1 has a base end held by the sensor head 11 while the tip end is set to a free end. The sensor head 11 has an axial center portion at a bottom portion C1 of the cylinder body C. The sensor block 12 is fixed to the bottom part C1 of the cylinder body C using a tightening bolt 13.

The magnet 2 is held on the inner peripheral side of a substantially cylindrical magnet case 21 made of a non-magnetic material. While being accommodated in B1, it is fixed to the piston portion R1 of the rod body R using the tightening bolts 23 in the presence of the sheet member 22 also made of a non-magnetic material, so that the inner circumference is on the outer circumference of the sensor rod 1. It is positioned to be nearby.

Therefore, in the above-described telescopic position detecting structure, when the external hydraulic supply / discharge source P supplies / discharges hydraulic pressure to / from the hydraulic chambers A1 and A2, that is, the rod body R moves relative to the cylinder body C. When the hydraulic cylinder is extended and retracted, the distal end of the sensor rod 1 is extended and retracted with respect to the chamber B. At this time, the magnet 2 and the sensor rod passing through the inner peripheral side of the magnet 2 Since 1 constitutes a stroke sensor, the state of the rod body R protruding and retracting with respect to the cylinder body C, that is, the expansion / contraction state of the hydraulic cylinder can be displayed numerically.

[0010]

However, there is a possibility that the following problems may be pointed out in the above-described telescopic position detecting structure.

To explain a little, first, since the sensor rod 1 in the above-described telescopic position detecting structure has a free end set at the free end, the front end of the sensor rod 1 is placed in the chamber B.
It is expected that the hydraulic cylinder expands and contracts when the tip of the sensor rod 1 is in contact with the inner circumference of the chamber B, as shown by a phantom diagram in FIG. In such a case, a galling phenomenon occurs between the two, and there is a fear that the sensor rod 1 may be broken due to the galling phenomenon.

When the sensor rod 1 is broken or the like, the stroke sensor itself having the sensor rod 1 becomes inoperable, and it is impossible to detect a predetermined expansion / contraction position.

Therefore, the inner circumference of the chamber B is finished with a sliding surface to reduce the sliding contact resistance.
It is possible to make a proposal to make it difficult to develop a galling phenomenon between the two even when the inner circumference comes into contact.

However, in general, a chamber B whose inner periphery is finished with a sliding surface on the shaft core of the rod body R so as to form a cylinder.
Is not easy to form, and if this is to be realized, the work is troublesome, and there is a fear that the cost of parts will increase unnecessarily.

When the hydraulic cylinder is set to be long, the chamber B is also set to be long. However, it is extremely difficult to form the long chamber B. Therefore, there is a fear that the cost of parts may be further increased.

The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a sensor rod which is in a state where the tip of the sensor rod comes into contact with the inner periphery of the chamber. At that time, it is possible to reduce the sliding contact resistance, thereby guaranteeing the operation of the stroke sensor that displays the expansion and contraction state of the hydraulic cylinder with accurate numerical values, and expecting the versatility of the hydraulic cylinder incorporating this stroke sensor to be improved. It is an object of the present invention to provide a telescopic position detecting structure which is optimal to perform the operation.

[0017]

In order to achieve the above object, the construction of the telescopic position detecting structure according to the present invention basically comprises connecting an internal hydraulic chamber to an external hydraulic supply / discharge source. A hydraulic cylinder comprising a cylinder body to be inserted and a rod body whose base end side is inserted into the cylinder body so as to be able to protrude and retract so as to define the hydraulic chamber in the cylinder body, and the base end side is held at the bottom of the cylinder body. The tip side has a sensor rod which is present in a chamber formed in the shape of an elongated hole in the shaft center of the rod body, and the shaft center of the piston part of the rod body in which the chamber is opened has the above-mentioned structure. In a telescopic position detection structure having a magnet adjacent to a sensor rod, a cylindrical body is formed in a cylinder form by finishing the inner periphery with a sliding surface while allowing the distal end side of the sensor rod to pass through the chamber. It is assumed that it has.

More specifically, in the above configuration, more specifically, a tubular body fitted into the chamber and having an inner periphery finished with a sliding surface, and a rod body connected to the tubular body. And a flange-shaped mounting portion fixed to the base end portion of the cylindrical body, and a magnet case formed substantially in a cylindrical shape and holding the magnet on the inner peripheral side is adjacent to the mounting portion of the cylindrical body. It is assumed that it is fixed in a state where it is held.

The sensor rod is made of a non-magnetic material, and has a base end held by the bottom of the cylinder body and a tip end held by a sensor rod holding member extending into the chamber. It is preferable that an outer periphery of a guide member provided continuously with an outer periphery of a tip end portion of the sensor rod holding member comes into sliding contact with an inner periphery of the cylindrical portion of the cylindrical body having a sliding surface.

At this time, it is assumed that the sensor rod holding member has a groove formed over the entire length from the base end to the front end,
It is assumed that a sensor rod is fitted in this groove.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on an embodiment shown in the drawings, but it is assumed that the expansion / contraction position detecting structure according to the present invention is built in a hydraulic cylinder similarly to the aforementioned conventional one. Also, the hydraulic cylinder is basically configured in the same manner as the conventional one described above.

Therefore, in the illustrated embodiment,
Portions having the same configuration are denoted by the same reference numerals in the drawings, and detailed description thereof will be omitted unless necessary, and the following description focuses on features that are characteristic of the present invention. .

First, as shown in FIG. 1, in the expansion / contraction position detecting structure according to the present invention, a chamber is formed in the shaft core of the rod body R in the shape of a long hole, and the distal end side of the sensor rod 1 is inserted therethrough. B has a cylindrical body 4 arranged in a fitted state.

The cylindrical body 4 is fitted into the chamber B to allow the distal end of the sensor rod 1 to penetrate the inner peripheral side, and a rod body connected to the cylindrical part 4a. And a mounting portion 4b formed in a flange shape and fixed to a piston portion R1 which is a base end portion of R.

By the way, in the illustrated embodiment, the outer periphery of the cylindrical portion 4a is notched shallowly to form a cylindrical gap 4c for reducing sliding friction with the inner periphery of the chamber B. However, it goes without saying that the formation of the cylindrical gap 4c may be omitted.

However, as shown in the figure, when the cylindrical gap 4c is formed, the insertability when the cylindrical body 4 is fitted into the chamber B is improved, and the cylindrical body 4 is moved to a so-called position. It is also advantageous in improving the rotativity at the time of alignment.

By the way, the cylindrical portion 4a constitutes a so-called cylinder, and has an inner periphery having a sliding surface finish. In the illustrated embodiment, the sensor rod 1 is integrally held on the inner peripheral side, which will be described later. The distal end side of the sensor rod holding member 3 is inserted.

Therefore, if the sensor rod holding member 3 is
That is, even if the tip of the sensor rod 1 comes into contact with the inner periphery of the chamber B, the sliding contact resistance at that time can be reduced, and even if the hydraulic cylinder expands and contracts in this state. In addition, the galling phenomenon is less likely to occur between the tip of the sensor rod 1 and the inner periphery of the chamber B.

In the illustrated embodiment, a guide member 33 is integrally held on the outer periphery of the distal end portion 3c of the sensor rod holding member 3, and the outer periphery of the guide member 33 is supported by a bearing member 33a. Is brought into sliding contact with the inner periphery of the cylindrical portion 4a.

Therefore, the distal end 3c of the sensor rod holding member 3, that is, the distal end of the sensor rod 1 is maintained in a so-called steady state under the arrangement of the guide member 33. That is, the tip of the sensor rod 1 is prevented from contacting the inner periphery of the cylindrical portion 4a in advance.

When the sensor rod holding member 3, that is, the sensor rod 1 is protruded and retracted from the chamber B, the guide member 33 slides on the inner periphery of the cylindrical portion 4a. Moves along the axis of the chamber B.

The base end 3 of the sensor rod holding member 3
a is held by the shaft core at the base end C1 of the cylinder body C, so that the sensor rod holding member 3, ie,
The sensor rod 1 is disposed on the axis of the cylindrical portion 4a as a whole.

As a result, in the above-mentioned cylindrical portion 4a, not only the above-mentioned galling phenomenon itself is not feared, but also the breakage of the sensor rod 1 due to the galling phenomenon is not feared. There is no fear that the stroke sensor will not operate due to breakage or the like.

On the other hand, the flange-shaped mounting portion 4b connected to the cylindrical portion 4b is in contact with the so-called bottom (not shown) of the enlarged diameter portion B1 of the chamber B in the rod body R. In this state, the rod body R is fixed to the piston portion R1 by use of the tightening bolt 34 in the closed state.

In the illustrated embodiment, the magnet case 21 holds the cylindrical magnet 2 on the inner peripheral side.
Is fixed to the mounting portion 4b using the tightening bolt 23.

By the way, in the embodiment shown in FIG. 2, the mounting portion 4b of the cylindrical body 4 is simultaneously and simultaneously fixed by the tightening bolts 23 for fixing the magnet case 21 holding the magnet 2 to a predetermined position. As a result of the joint tightening, the number of parts can be reduced by the amount of the tightening bolt 34.

Although not shown, the magnet case 2
1 may be screwed to the mounting portion 4b fixed by the tightening bolt 34, in which case the tightening bolt 23
Therefore, the number of parts can be reduced.

Therefore, since the above-mentioned cylindrical body 4 has the mounting portion 4b formed in a flange shape, the cylindrical portion 4a of the cylindrical body 4 can be easily fixed at a predetermined position. Needless to say, the magnet case 21, that is, the magnet 2 can be held by the shaft core of the piston portion of the rod body R via the mounting portion 4 b.

The cylindrical body 4 has a cylindrical portion 4a finished in a so-called cylinder manner, so that the inner periphery of the chamber B is finished in a cylinder manner directly. The number of processes in the rod body R can be reduced.

In addition, since the cylindrical portion 4a of the cylindrical body 4 is set so as to be fitted to the inner periphery of the storage chamber B, the diameter of the storage chamber B can be made large. A rod body R for forming a chamber B as compared with the conventional case shown in FIG.
This also facilitates the processing operation in.

Next, in the telescopic position detecting structure according to the present invention, the sensor rod 1 is
It is said to be held.

The sensor rod holding member 3 is
It is assumed that the base end portion 3a is formed of a non-magnetic solid body, and the base end portion 3a is held by the sensor block 12 constituting the shaft center portion at the base end portion C1 of the cylinder body C. Of the container B.

At this time, the sensor rod holding member 3 integrally has a connection bracket 31 formed in a flange shape on the outer periphery of the base end portion 3a. It is stated that the sensor block 12 holds the sensor block 12 by being fixed thereto.

As for the method of holding the sensor rod holding member 3 on the sensor block 12, as long as the sensor rod holding member 3 is arranged at a predetermined position, any method may be selected in place of the above-described method. The good thing is, of course.

The sensor rod holding member 3 has a groove 3b formed over the entire length from the base end to the distal end. As shown in FIG. 3, the sensor rod 1 is fitted into the groove 3b. It is said that it is held in the mounted state.

Therefore, as long as the deflection and runout of the sensor rod holding member 3 are effectively prevented, the deflection and runout of the sensor rod 1 held in the sensor rod holding member 3 in an fitted state are also effective. Will be blocked.

Incidentally, the cross-sectional shape and the depth of the groove 3b in the sensor rod holding member 3 will be briefly described. As shown in FIG. 3, the cross-sectional shape is a solid circle, and the depth of the groove 3b is It is assumed that the sensor rod 1 is set deeply so as to be disposed on the shaft core of the sensor rod holding member 3.
As shown in the figure, the cross-sectional shape is also a solid octagon,
Further, the depth of the groove 3b may be set to be shallow so that the sensor rod 1 is disposed eccentrically on the outer peripheral side of the sensor rod holding member 3.

The point is, when the sensor rod 1 is extended to the chamber B while being held by the sensor rod holding member 3,
A configuration is selected in which the position of the sensor rod 1 is kept constant without changing in the radial direction of the chamber B.

In this sense, if the sensor rod holding member 3 is made of a solid body, it can be said that the bending and deflection of the sensor rod holding member 3 can be effectively prevented. As shown in the figure, the sensor rod holding member 3 is made of a pipe, and the groove 3
b may be formed by pressing the outer periphery of the pipe body in the axial direction.

When the sensor rod holding member 3 is made of a pipe body, it contributes to the reduction of the weight of the sensor rod holding member 3 as compared with the case where the sensor rod holding member 3 is made of a solid body. In addition, it is possible to eliminate in advance the inconvenience that the sensor rod holding member 3 is bent due to its own weight due to its own weight, and therefore, it is possible to more effectively prevent the sensor rod holding member 3 from bending or oscillating. Is advantageous.

Since the sensor rod holding member 3 is formed of a pipe and the groove 3b is formed by press molding, the groove 3b is formed by cutting or the like in a solid body. In addition, it can be said that the labor of processing is greatly reduced, which is advantageous in improving the productivity.

By the way, in the telescopic position detecting structure according to the present invention, since the so-called squeezing phenomenon does not appear around the sensor rod 1 and the sensor rod holding member 3 holding the sensor rod 1, the sensor rod 1 and the sensor rod holding member Needless to say, bending or the like caused by the pressure in 3 is not exhibited.

[0053]

As described above, according to the present invention, since the cylinder is fitted in the chamber, the diameter of the chamber can be made large, and the diameter of the chamber can be reduced. As compared with the case where the diameter is set, the processing operation on the rod body is facilitated.

At this time, since the cylindrical body has a cylindrical portion whose inner periphery is finished in a cylinder form, the number of machining on the rod body is reduced as compared with the case where the inner periphery of the chamber is directly finished in the cylinder form. Will be able to do it.

Further, since the cylindrical body has a flange-like mounting portion fixed to the base end of the rod body, the magnet is formed substantially in a cylindrical shape and holds the cylindrical magnet on the inner peripheral side. This makes it possible to fix the case to the above-mentioned mounting portion. Therefore, even in this respect, it is possible to increase the diameter of the chamber, thereby facilitating the working operation on the rod body.

In the present invention, when the sensor rod is held by the sensor rod holding member, the bending of the sensor rod is prevented as long as the bending and deflection of the sensor rod holding member are effectively prevented. And runout will be effectively prevented.

When a guide member is continuously provided on the outer periphery of the distal end of the sensor rod holding member, and the outer periphery of the guide member is slidably contacted with the inner periphery of the cylindrical body, the distal end of the sensor rod holding member is required. That is, the distal end of the sensor rod 1 is maintained in a so-called swing-prevented state under the arrangement of the guide member. Therefore, the distal end of the sensor rod 1 is located on the inner periphery of the chamber, that is, the cylindrical portion of the cylindrical body. Contact with the inner periphery is prevented in advance.

At this time, provided that the base end of the sensor rod holding member is fixed at a predetermined position, the sensor rod holding member is always disposed at a constant position on the inner peripheral side of the cylindrical body as a whole. It will be.

When the sensor rod is held by the sensor rod holding member, even if the sensor rod is eccentrically held, there is no danger that the position of the sensor rod will be deviated and stable detection will be possible.

Further, when the sensor rod holding member is made of a pipe, it contributes to the reduction of the weight of the sensor rod holding member as compared with the case where the sensor rod holding member is made of a solid body. It is possible to eliminate in advance the inconvenience of causing the user to bend due to his / her own weight, and therefore, it is possible to more effectively prevent the sensor rod holding member from bending or oscillating.

As a result, according to the present invention, even if the tip of the sensor rod constituting the stroke sensor comes into contact with another part, the operation of the stroke sensor can be guaranteed and the productivity can be improved. Therefore, there is an advantage that is most suitable for expecting improvement in versatility of a hydraulic cylinder incorporating a stroke sensor.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a hydraulic cylinder equipped with a telescopic position detecting structure according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view partially showing a hydraulic cylinder equipped with a telescopic position detecting structure according to another embodiment.

FIG. 3 is a longitudinal sectional view of a rod portion shown by line XX in FIG. 1;

FIG. 4 is a sectional view of a sensor rod holding member according to another embodiment.

FIG. 5 is a sectional view of a sensor rod holding member according to still another embodiment.

FIG. 6 is a diagram showing a hydraulic cylinder equipped with a telescopic position detecting structure as a conventional example, similarly to FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sensor rod 2 Magnet 3 Sensor rod holding member 3a Base end 3b Groove 3c Tip 4 Inner cylinder 4a Cylindrical part 4b Attachment part 4c Cylindrical gap 11 Sensor head 12 Sensor block 13, 23, 32, 34 Tightening bolt 21 Magnet Case 22 Seat member 31 Connection bracket 33 Guide member 33a Bearing member A Hydraulic chamber B Chamber B1 Large diameter section C Cylinder body C1 Bottom section P Hydraulic supply / discharge source R Rod body R1 Piston section

Claims (2)

[Claims] 1. A cylinder body for communicating an internal hydraulic chamber with a hydraulic supply / discharge source disposed outside, and a rod having a base end inserted through the cylinder body so as to protrude and retract to partition the hydraulic chamber in the cylinder body. A hydraulic cylinder comprising a body, a base end side of which is held by a bottom part of the cylinder body, and a tip end side having a sensor rod which is provided in a chamber formed in a long hole shape in a shaft core part of a rod body. In addition, in a telescopic position detection structure having a magnet adjacent to the sensor rod at a shaft portion of a piston portion of a rod body having an opening of the chamber, the distal end side of the sensor rod is inserted into the chamber. Characterized in that it has a cylindrical body which is set in a cylinder form by finishing the inner surface with a sliding surface while permitting the expansion and contraction. 2. A cylindrical part which is fitted in a chamber and whose inner periphery is finished with a sliding surface, and a flange-like mounting which is connected to the cylindrical part and is fixed to a piston part of a rod body. The magnet case, which is formed in a substantially cylindrical shape and holds the magnet on the inner peripheral side, is fixed in a state adjacent to the mounting portion of the cylindrical body while having a portion. Stretch position detection structure