JPS62184302A - Cylinder device - Google Patents

Abstract

PURPOSE:To detect the stroke of a piston continuously over the entire range by using a resistance wire as one of two conductors which are short-circuited by the 2nd magnetic body displaced in a passage according to the displacement of the 1st magnetic body. CONSTITUTION:The piston 37 is slid and displaced axially in an inner cylinder 34 with pressure oil supplied into the inner cylinder 34 and a magnetic ring 38 is also displaced axially in the inner cylinder 34 along with the piston 37. Then, a body 41 to be detected is displaced axially in the passage 40A of a semicircular tube 40 with the magnetic force of the magnetic ring 38 so as to follow up the displacement of the magnetic ring 38, thereby sliding on each resistance wire 42. Consequently, each resistance wire 42 is short-circuited by the body 41 to be detected and varies in resistance value, and the displacement of the body 41 to be detected is led out as variation in the quantity of electricity. Consequently, the stroke of the piston 37 is detected continuously over the entire range.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cylinder device 1 used as an actuator for, for example, construction machinery, and more particularly to a cylinder device capable of detecting the stroke of a piston.

[Prior art]

BACKGROUND ART In general, cylinder devices are known that include a tube that constitutes a cylinder and a piston that is slidably inserted into the tube.

When this type of cylinder device is operated by automatic control, a piston stroke detection mechanism is used to detect the stroke of the piston, that is, the amount of displacement of the piston.

FIG. 5 shows a cylinder device equipped with a piston stroke detection mechanism according to the prior art.

In the figure, ``■'' is a metal tube constituting a cylinder, and both ends of the tube 1 are covered with a head cover 2 and a rod cover 3. Then, supply and discharge ports 4 are provided in the radial direction on one end side and the other end side of the tube l, respectively.
．． 5 is drilled. A piston 6 is slidably inserted into the tube 1, and the piston 6 defines two oil chambers A and B within the tube 1. And each oil chamber A
, B, oil is supplied and discharged through the respective supply/discharge balls 1-4 and 5, and the piston 6 is slid and displaced within the tube 1 by the pressure between the respective oil chambers A and B. ing. 7 is-・
A piston rod whose end is fixed to the piston 6 within the tube l and whose other end protrudes outside through the rod cover 3,
A mounting eye 8 is provided at the protruding end of the piston rod 7.

9 is a detection rod formed in an L shape;
The base end 9A of is fixed to the piston port and the door mounting eye 8 with screws or the like. The tip end 9B of the detection rod 9 extends in the axial direction of the tube 1 via a guide 10.10 that protrudes in the radial direction of the rod rod 3 and the tube 1i7. Reference numeral 11.11 indicates a limit switch provided on the outer circumference of one end of the tube 1 and the outer circumference of the head cover 2, and each limit switch 11 is activated by the tip 9B of the detection rod 9 when the detection rod 9 is displaced in the axial direction together with the piston 6. ON.

It is turned off, thereby detecting the stroke of the piston 6.

In the cylinder device configured in this way, the supply/discharge port 4
When oil is supplied from the oil chamber A and the pressure in the oil chamber A becomes high, the piston 6 is displaced to the left in the figure, and the oil in the oil chamber B is supplied to the supply/discharge port 5.
When the oil is supplied from the supply/discharge port 5, the pressure in the oil chamber B becomes high and the piston 6 is displaced to the right in the figure, and the oil in the oil chamber A is discharged from the supply/discharge port 4. be done. When the piston 6 is displaced to the right in the figure, the detection rod 9 is also displaced to the right in accordance with this, so the tip 9B of the detection rod 9 can be detected by each limit switch 11. Strokes can be detected.

However, in the prior art described in (1), since the stroke of the piston 6 is detected by each limit switch 11, there is a drawback that the stroke of the piston 6 cannot be detected continuously.

In addition, as another conventional technique, as shown in FIG.
A is known in which the stroke of the piston 6, which is displaced in response to the expansion and contraction of the piston opening/end 7, is detected by the potentiometer 21.

However, this conventional technology has the drawback that the stroke of the piston 6 can only be detected within a certain range because the potentiometer 21 has a length limit, and detection errors occur due to changes in the external environment, such as temperature changes. be.

[Problem that the invention seeks to solve]

The present invention was developed in view of the drawbacks of the above-mentioned conventional techniques. It is an object of the present invention to provide a cylinder device that can reliably prevent errors from occurring.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides a tube constituting a cylinder, 1 a piston slidably inserted into the tube, and 1 a piston. a first magnetic body embedded in the outer peripheral side of the tube and displaced in the tube together with the piston; a passage provided in the tube and extending in the axial direction of the tube; and a first magnetic substance provided movably within the passage;
A second magnetic body is disposed within the passageway and extends in the axial direction in accordance with the displacement of the first magnetic body when the piston is slidably displaced within the tube.

A configuration is adopted in which two conducting wires are short-circuited by the second magnetic material, and at least one of the conducting wires is a resistance wire.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 4.

1 to 3 show a first embodiment of the invention.

In the figure, 31 is a head cover 32, a rod cover 3
A tube that together with 3 constitutes a cylinder, and the tube 3
1 includes an inner cylinder 34 formed into a thin cylindrical shape of reinforced plastic such as FRP or non-magnetic material such as aluminum alloy, and an inner cylinder 34 formed of reinforced plastic prepreg and provided in close contact with the outer peripheral surface of the inner cylinder 34. The outer cylinder 36 is made of a strong material such as jμ fiber or glass fiber. It is molded from reinforced plastic material using the filament winding method described below. Here, the intermediate cylinder 35 has 1
For example, a laminate 35A made by laminating a plurality of prepregs made of glass fiber, carbon fiber, etc. or mat impregnated with a thermosetting resin and having a thickness corresponding to the height of the semicircular tube 40 described later. is formed, and before the laminated plate 35A is hardened, the laminated plate 35A is tightly wrapped around the outer peripheral surface of the inner cylinder 34, a notch 35B is formed between both ends of the laminated plate 35A, and a semicircular tube is formed in the notch 35B. 40 is sandwiched therebetween.

On the other hand, the outer cylinder 36 is formed by impregnating a thread-like M&male material such as carbon fiber or glass mm with a thermosetting resin such as polyimide resin or epoxy resin, and by a filament winding method. That is, the laminated plate 35
A is wound around the outer periphery of the inner cylinder 34, and the semicircular tube 40 is inserted into the notch 35B, and then the filamentous fiber material impregnated with the thermosetting resin is wrapped around them at a predetermined winding angle to cross each other. The outer cylinder 36 is formed by winding it, finishing it to a required thickness, and thermosetting it. Then, 034. Intermediate I: A35 and outer cylinder 3
6 has a head cover 32 and a rod cover 33 at both axial ends.
It has been carried out by. Further, a small hole 32A communicating with the inside of the semicircular tube 40 is bored in the axial direction of the head cover 32.

A piston 37 is slidably inserted into the inner cylinder 34, and the piston 37 is made of a non-magnetic material such as an aluminum alloy, non-magnetic stainless steel, or reinforced plastic. It is divided into oil chambers A and B. 3rd is a magnetic ring as a first magnetic body buried in the outer circumferential side of the screw 37, and the magnetic ring 38 is made of a permanent magnetic material and moves the detected object 41, which will be described later, to the closest position. It is designed to attract. The magnetic ring 38 is configured to be integrally displaced within the inner portion 034 together with the piston 37. A piston rod 39 has one end fixed to the piston 37 and the other end protruding to the outside through the rod cover 33. The piston rod 39 expands and contracts from the tube 31 in accordance with the sliding displacement of the piston 37. The output is derived from the other end.

Note that when the piston rod 39 does not rotate relative to the tube 31, the magnetic ring 3
8 does not need to be provided over the entire circumference of the piston 37, and may be provided only at a portion corresponding to the diagonal tube 40, for example.

Next, 40 is a semicircular tube located on the outer peripheral side of the cylinder 34 and disposed within the frame portion 35B of the intermediate cylinder 35.

The semicircular tube 40 is formed into a slender shape by splitting an elongated circular tube made of a non-magnetic material such as FRP or aluminum alloy, and is located on the bottom side or on the outer peripheral surface of the inner tube 34, and has intermediate tubes on both sides. It is positioned so as to be sandwiched within the notch 35B of 35. The semicircular tube 40 extends along the entire length of the Φ space 35 in the axial direction, and forms a passage 4OA inside.

Further, the semicircular tube 40 has an open end 40B on the side thereof, and the open end 40B is covered over the entire length in the axial direction by an outer member 036. Note that when the semicircular tube 40 is formed of a conductive material such as an aluminum alloy, an electrically insulating coating or the like is applied to the inner surface of the tube in advance.

Reference numeral 41 denotes an object to be detected as a second magnetic body movably inserted into the passage 4OA of the semicircular tube 40, and the object to be detected 41 is made of a conductive magnetic material such as iron or nickel and has a substantially cylindrical shape. It is configured to slide on each resistance wire 42, which will be described later, within the passage 40A. Then, the detected object 41
is caused by the magnetic force of the magnetic ring 38.
The piston 37 is attracted to the inner cylinder 3 at all times.
4, the piston 37 and the magnetic ring 38 are displaced in the axial direction following the displacement of the piston 37 and the magnetic ring 38. At this time, the detected object 41 slides on each resistor 1421 and short-circuits each resistance wire 42, so that the position of the detected object 41 is detected as a change in the resistance value of each resistance wire 42. It has become.

42. 42 is a resistance wire extending in the axial direction into the passage 40A of the round pipe 40 and being cut out.

Each of the resistance wires 42 is formed in a straight line with a predetermined electrical resistivity using a nickel alloy such as Mar/Ganine or Constatta 7, and is attached to the inner surface of the semicircular tube 40 along the entire length in the axial direction (by means of adhesion or the like). The resistance wires 42 are spaced apart from each other at a predetermined distance from phase-1, and are short-circuited by the detected object 41 as shown in FIG. Furthermore, 43 and 43 are lead wires whose one end is connected to the other end of each of the resistance wires 42 and led out from the small hole 32A of the hent cover 32, and the other end of each of the lead wires 43 is connected to the terminal C, D, and a predetermined voltage is applied between the ends pc and D.

As a result, due to the displacement of the detected object 41, each resistance yj
Since the resistance value of 42 changes, the displacement of the detected object 41 is detected as a change in the amount of electricity between terminals C and D.

Next, the operation of the cylinder device configured as described above will be explained.

First, the piston 37 is connected to each supply/discharge port (
The magnetic ring 38 is slidably displaced in the axial direction within the inner cylinder 34 by pressure oil supplied into the inner cylinder 34 from a source (not shown), and the magnetic ring 38 is also displaced in the axial direction within the inner cylinder 34 together with the piston 37 . Then, the detected object 41 follows the displacement of the magnetic ring 38 due to the magnetic force of the magnetic ring 38 and moves along the passage 40 of the deformed tube 40.
゛Displace in the axial direction within A and slide on each resistance line 42 north.

As a result, each resistance wire 42 is short-circuited by the detected object 41, and the resistance value of each resistance wire 42 changes, so that the displacement of the detected object 41 can be extracted as a change in the amount of electricity. According to the embodiment, by extracting the displacement of the detected object 41 as a change in electricity iJ, the position of the piston 37 in the inner cylinder 34, ■! The stroke of the piston 37 can be continuously detected as an electrical quantity, and by manually inputting this to a control device or the like, it becomes possible to control a solenoid valve or the like. The semicircular tubes 40 extend along the entire length of the inner tube 34 in the axial direction, and each resistance wire 42 extends over the entire length within the FI tube 40. 42 and the detected object 41, the stroke of the piston 37 can be continuously detected over the entire range.

Furthermore, the detected object 41 follows the magnetic ring 38 and short-circuits each resistance wire 42, and the detected object 41 and each resistance i
42 is connected to the inner cylinder 34 through the semicircular tube 40. Since it is covered by the intermediate cylinder 35 and the outer cylinder 36, the stroke of the piston 37 can be reliably detected without being affected by changes in the external environment or the like.

Further, according to this embodiment, the tube 31 is composed of an inner tube 34, an intermediate tube 35, and an outer tube 36, and the inner tube 34 is made of FRP.
The prepreg laminate 35A is wrapped around the inner cylinder 311, and the notch 35 is
The intermediate tube 35 was formed by sandwiching the semicircular tube 40 inside B, and the outer tube 36 with a predetermined thickness was formed using the filament winding method. It can be formed to be strong, improve shock absorption and fatigue resistance, and can also firmly hold the FJ pipe 40 between the inner cylinder 34 and the outer cylinder 36 via the intermediate load 35, improving reliability. can be increased. Since the Φ space 35 and the outer cylinder 36 are brought into close contact around the inner cylinder 34 to cover the inner cylinder 34, the inner cylinder 34 is
3. Form into the meat. The magnetic force of the magnetic ring 38 can be reliably applied to the detected object 41. Furthermore, the outer cylinder 36 can eliminate a "bar state" in which the magnetic force of the magnetic ring 38 adversely affects the outside.

FIG. 4 shows a second embodiment of the present invention. In this embodiment,
The same components as in the first embodiment shown in FIGS. 1 to 3 described above are given the same reference numerals, and their explanations will be omitted.

On the other hand, the feature of this embodiment is that the tube 51 constituting the cylinder is composed of an inner tube 52 and an outer tube 53, and a longitudinal groove 54 extending in the axial direction is provided in the outer peripheral surface of the inner tube 52. The inner surface of the longitudinal groove 54 forms a passage 54A through which the detected object 4I can move.

Here, although the inner cylinder 52 is formed almost the same as the inner cylinder 34 used in the first embodiment, it is formed thicker than the inner cylinder 34, and the longitudinal groove 52 is formed on the outer peripheral surface of the inner cylinder 52. Or it is recessed. The longitudinal groove 54 has a semicircular cross section, and each resistance wire 42 is attached to the inner surface thereof by means such as a tangent. On the other hand, the outer cylinder 53 is made by using the filament winding method, similar to the outer cylinder 36 used in the example of 51, to tightly fit a filamentous fiber material impregnated with a thermosetting resin around the inner cylinder 52. It is formed by winding it with a nozzle and curing it with heat. The outer cylinder 53 covers the longitudinal groove 54 over its entire length in the axial direction. In addition, when the inner tube 52 is formed of a conductive material such as an aluminum alloy, an electrically insulating coating may be applied to the inner surface of the longitudinal groove 54 in advance.

Also in this embodiment configured in this way, the object to be detected 41 is inserted into the passage 54A formed by the longitudinal groove 54, and the object to be detected 41 is connected to each resistance wire 4 according to the displacement of the piston 37.
By sliding 2k, the stroke of the piston 37 can be detected, and almost the same effect as in the first embodiment can be obtained. In this embodiment, since the intermediate tube 35 and semicircular tube 40 used in the first embodiment can be omitted, the structure of the tube 51 can be simplified and the workability during manufacturing can be improved.

In each of the above embodiments, the semicircular tube 40 or the longitudinal groove 54
are formed into a semicircular shape, but the cross-sectional shape of these may be formed into a substantially U-shape or a substantially U-shape T. Also, instead of the semicircular tube 40, an elongated circular tube, etc. In this case, P resistance wires 4 are connected to the inner peripheral surface of the circular pipe, etc.
Each resistance wire 42 connects to the object 41 to be detected.
It may be short-circuited by

Furthermore, in each of the embodiments described above, the magnetic ring 38 is made of a permanent magnet, but the object to be detected 41 is made of a permanent magnet, and the magnetic ring 38 is made of a magnetic material such as iron, carbon dioxide, or the like. Good too.

Alternatively, both may be formed of Mizuku porcelain 1. Furthermore, when the electrical resistance of the detected object 41 is large, a core conductive coating may be applied to the surface of the detected object 41.

Further, in each of the above embodiments, two resistance wires 42 are used, but one of the resistance wires 42 may be a conductive wire with high conductivity. Further, the piston 37 does not necessarily have to be made of a non-magnetic material, and the outer cylinder 36 (53) may be formed using a tape winding method instead of a filament winding method.

Furthermore, in each of the above embodiments, the tube 31 (51)
The tube 31 (51) is made of a non-magnetic material such as an aluminum alloy or reinforced plastic. In this case, a passage extending in the axial direction may be bored in the cylinder, and the detected object 41, the resistor &942, etc. may be disposed inside. A non-magnetic elongated tube may be attached in the axial direction on the outside and inside of the cylindrical body of the tube, and the object to be detected 41, the resistance wire 42, etc. may be disposed within this elongated tube.

〔Effect of the invention〕

As described in detail below, according to the present invention, the first magnetic material is disposed on the outer peripheral side of the piston, a passage extending in the axial direction is provided in the tube, and the first magnetic material is disposed in the passage. A second magnetic body that is displaced in the passage according to the displacement of the second magnetic body and two conductive wires short-circuited by the second magnetic body are provided, and at least one of the conductive wires is a resistance wire. The resistance value of the resistance wire can be changed by displacement of the second magnetic body,
Due to this change in resistance value, the position of the piston, that is, the stroke of the piston can be continuously detected over the entire range via the second magnetic body. Furthermore, since a second magnetic material, resistance wire, etc. are provided within the tube passage, the stroke of the piston can be detected without being affected by changes in the external environment.

[Brief explanation of drawings]

1 to 3 show a first embodiment of the present invention, in which FIG. 1 is a longitudinal sectional view of the cylinder device, FIG. 2 is a sectional view in the direction of arrow II-II in FIG. 1, and FIG. The figure is an electric circuit diagram for detecting the stroke of a piston, which includes the object to be detected and each resistance wire shown in FIG. 2, and FIG. 4 is a sectional view similar to FIG. 2 showing a second embodiment of the present invention. 55 is a longitudinal sectional view showing a cylinder device according to the prior art, and FIG. 6 is a longitudinal sectional view showing a cylinder device according to another prior art. 31.51...tube, 32.52...inner cylinder. 35...Intermediate cylinder, 36.53...Outer cylinder, 37...
Piston, 38... Magnetic ring, 39... Piston rod, 40... Semicircular tube, 4OA... Passage, 41...
...Object to be detected, 42...Resistance wire, 43...Lead wire, 54...Vertical groove, 54A...Passway. Patent applicant: 1 person)'', Attorney for Construction Machinery Co., Ltd. Kazuhiko Hirose, Naoki Nakamura, Figure 2, Figure 3

Claims (3)

[Claims] (1) a tube constituting a cylinder; a piston slidably inserted into the tube; and a first magnetic body embedded in the outer circumferential side of the piston and displaced in the tube together with the piston; a passage provided in the tube and extending in the axial direction of the tube; and a passage provided movably within the passage, in response to displacement of the first magnetic body when the piston slides within the tube. It consists of a second magnetic body that is displaced within the passage, and two conductive wires that are provided extending in the axial direction within the passage and are short-circuited by the second magnetic body, and at least one of the conductive wires is A cylinder device in which one side is configured as a resistance wire. (2) The tube has an inner cylinder made of a non-magnetic material and a middle part made of prepreg made of a reinforced plastic material, which is provided in close contact with the outer peripheral surface of the inner cylinder with a notch in a part. a cylinder, and an outer cylinder formed of a reinforced plastic material and provided in close contact with the outer peripheral surface of the intermediate cylinder, the passage being located on the outer peripheral side of the inner cylinder and extending into the notch of the intermediate cylinder. The cylinder device according to claim (1), which is formed by a non-magnetic semicircular tube. (3) The tube consists of an inner cylinder made of a non-magnetic material and an outer cylinder made of a reinforced plastic material and provided in close contact with the outer peripheral surface of the inner cylinder, and the passage is formed in the inner cylinder. The cylinder device according to claim 1, wherein the cylinder device is formed by a longitudinal groove recessed in the outer peripheral surface and having a semicircular cross section.