JPH0320592Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field] The present invention is a shock absorber, in particular, a shock absorber that smoothly absorbs dynamic body load energy and stops it by the resistance force generated in a piston that is moved in a fluid sealed in a cylinder. This invention relates to a shock absorber that can be

[Background technology]

As this type of shock absorber, one having the following structure has been proposed.

That is, a piston that is movable in the axial direction of the cylinder and a piston rod that moves together with the piston are provided in a cylinder that is closed at one end.
After injecting fluid into the cylinder, the open end of the cylinder is sealed with a sealing member, a dynamic load is applied to the piston rod that penetrates the sealing member and protrudes outside the cylinder, and the dynamic load energy is smoothly absorbed. It is a buffer with a structure that allows

However, in the case of the above-mentioned shock absorbers, the position of the piston is determined only when the piston is in contact with the closed end of the cylinder, or when the piston is in contact with the closed end of the cylinder, or when the piston is fixed by the seal provided at the open end of the cylinder. In either case, the piston is in contact with the stop member, and it is difficult to obtain information on the determined position of the piston as an output signal.

In particular, it is extremely difficult to obtain position information of the piston during its stroke.

As a result, when used together with a control device that controls the position of a moving object, for example, there is a drawback that the control device cannot grasp the operating state of the shock absorber and cannot accurately control the position of the moving object.

Therefore, it is conceivable to provide a piston position detection mechanism on the external side surface of the shock absorber, but in this case, there is a problem that the structure of the device using the shock absorber itself becomes complicated and large.

[Purpose of invention]

The purpose of this invention is to
It is an object of the present invention to provide a shock absorber which outputs position information of a piston as a signal and whose operating state can be grasped from the outside.

Another object of the present invention is to provide a buffer that is easy to maintain.

Still another object of the present invention is to provide a shock absorber that can be made smaller.

[Structure of the idea]

The shock absorber of the present invention includes a bottomed cylinder made of a non-magnetic material, a piston located within the cylinder and movable in the axial direction of the cylinder, a piston rod that moves together with the piston, and a piston rod that is movable together with the piston. A fluid to be enclosed, an accumulator that absorbs changes in the volume of this fluid, a magnetism generating means that is locked to the inner end of the piston rod in the cylinder and moves together with the piston, and a magnetism generating means that is attached to the outer end surface of the cylinder on the axially inner side of the cylinder. The above object is achieved by a structure including a magnetic sensing means which is removably fitted into a recess formed to protrude from the magnetic field and senses the magnetism generated from the magnetic generating means.

〔Example〕

The figure is a sectional view of a shock absorber that is an embodiment of the present invention.

A piston rod 2 is inserted into a cylindrical cylinder 1 made of a non-magnetic material and closed at one end, and a flange portion 2a is formed at the inner end of the piston rod 2 located inside the cylinder 1. ing.

Further, a permanent magnet (magnetism generating means) is fitted and fixed at the tip of the piston rod 2.

At the center of the closed end of cylinder 1, cylinder 1
A recess 1a projecting in the axial direction is formed inside the permanent magnet 3, and a magnetic sensing element 3a (magnetic sensing means) for detecting the magnetism generated from the permanent magnet 3 is removably fitted inside the recess 1a. Fixed.

A piston 4 is positioned between the permanent magnet 3 and the flange portion 2a and is fitted so as to be movable in the axial direction of the cylinder 1.

Further, a holder 5 is positioned on the open end side of the cylinder 1, and the piston rod 2 is guided through the center of the cylinder 1 so as to be movable in the axial direction.

The holder 5 is fixed to the cylinder 1 by a spacer 6 and a retainer 7, and the fluid in the cylinder 1 is kept sealed by an O-ring 8.

Similarly, a gasket 9 is provided at the portion where the piston rod 2 passes through the holder 5, and is sealed in the cylinder by the movement of the piston rod 2.
For example, fluid 10 such as silicone oil is prevented from leaking to the outside.

Around the small diameter part of the holder 5, an expandable and deflated accumulator 11 is provided, for example, in the form of a closed cell sponge, and when the piston rod 2 enters the inside of the cylinder 1, the cylinder 1 is removed. The fluid 10 inside passes through the plurality of fluid passages 5a and flows into the space A where the accumulator 11 is located, and by contracting the accumulator 11, the internal pressure of the cylinder 1 is prevented from rising above a predetermined value. The structure is such that

A plurality of passages 4a are formed in the center of the piston 4 through which the piston rod 2 passes, and communicate with a plurality of grooves 4b formed radially on the end surface of the piston 4.

Furthermore, a plurality of through holes 3b are formed in the permanent magnet 3 in the axial direction of the cylinder 1, and a piston 4 is formed in the permanent magnet 3.
is in a state where it is pressed by the permanent magnet 3, it communicates with the flow path 4a and the groove 4b, so that the fluid present on the left side of the piston 4 can easily flow into the space on the right side of the piston 4. .

A non-magnetic coil spring 12 is provided between the end face of the permanent magnet 3 and the closed end of the cylinder 1, and constantly biases the piston rod 2, to which the permanent magnet 3 is fixed, in a direction to push it out of the cylinder 1. ing.

Further, a threaded portion 13 is carved on the outer periphery of the cylinder 1, so that it can be easily attached to a predetermined device (not shown).

Next, the operation of this embodiment will be explained.

When a dynamic load is applied to the distal end of the piston rod 2 protruding from the outside of the cylinder 1, the piston rod 2 begins to move inside the cylinder 1 against the elastic force of the coil spring 12.

At this time, the piston 4 is pressed by the fluid 10 present on the right side of the piston 4, and is pressed against the flange portion 2a of the piston rod 2.

As a result, the fluid 10 passing through the through hole 3b of the permanent magnet 3, the groove 4b of the piston, and the flow path 4a is prevented from flowing into the left side of the piston 4, and the fluid 10 existing on the right side of the piston 4 is prevented from flowing into the left side of the piston 4. It flows into the left side of the piston 4 passing only through a narrow portion formed by the outer circumference and the inner wall surface of the cylinder 1.

Therefore, a large braking force is generated in the piston 4 due to the viscous resistance of the fluid, the dynamic body load energy is smoothly absorbed, and the piston rod 2 gradually approaches the closed portion of the cylinder 1.

At this time, the permanent magnet 3 locked to the inner end of the piston rod 2 gradually approaches the magnetic sensing element 3a arranged at the closed end of the cylinder 1, and the permanent magnet 3 is detected by the magnetic sensing element 3a. The magnetism from the magnet 3 becomes stronger in proportion to the approach of the piston rod.

Then, when the piston rod 2 approaches the closed end of the cylinder 1 and the strength of the sensed magnetism exceeds a desired threshold, the magnetic sensing element 3a is activated and provides an output signal to a control device (not shown).

When the dynamic load is released, the piston rod 2 begins to move to the left in the figure due to the elastic force of the coil spring 12.

At this time, the piston 4 separates from the flange portion 2a of the piston rod 2 and moves to the side surface of the permanent magnet 3.

As a result, the fluid 1 present on the left side of the piston 4
0 easily flows into the right side of the piston 4 through the flow path 4a in the center of the piston 4, the groove 4b, and the through hole 3b of the permanent magnet 3, and no large braking force is generated in the piston 4.

In this way, the piston rod 2 quickly returns to its unloaded position.

At this time, the permanent magnet 3 moves away from the magnetic sensing element 3a together with the piston rod 2, so the magnetic strength detected by the magnetic sensing element 3a gradually decreases until the magnetic strength becomes below a desired threshold value. By detecting this using the magnetic sensing element 3a, the return movement of the piston rod 2 can be accurately grasped from outside the shock absorber.

It goes without saying that the present invention is not limited to the embodiments described above, and can be modified in various ways without departing from the gist thereof.

〔effect〕

(1) A cylinder made of a non-magnetic material having a cylindrical shape with a bottom, a piston located within the cylinder and movable in the axial direction of the cylinder, a piston rod that moves together with the piston, and a piston rod enclosed within the cylinder. a fluid, an accumulator that absorbs changes in the volume of the fluid, a magnetism generating means that is locked to the inner end of the piston rod in the cylinder and moves together with the piston, and an axially inner portion of the cylinder that is attached to the outer end surface of the cylinder. and a magnetic sensing means that is detachably fitted into a recess formed to protrude to the side and senses the magnetism generated from the magnetism generating means.
The accurate position of the piston within the cylinder can be detected without complicating the structure, and the operating state of the shock absorber can be accurately grasped outside the shock absorber.

(2) As a result of (1) above, it is possible to accurately control the position of a moving object.

(3) As a result of (1) and (2) above, accidents caused by the impact of moving objects,
Breakdowns, etc. can be prevented.

(4) Since the structure is such that the magnetic sensing means is removably fitted into the recess formed in the end face of the cylinder, maintenance and management during normal use can be easily performed.

(5) Since the structure is such that the magnetic sensing means is removably fitted into the recess formed on the end face of the cylinder, the width and longitudinal dimensions of the shock absorber can be reduced, and the shock absorber can be easily attached to the shock absorber. It is possible to downsize the equipment used.

[Brief explanation of the drawing]

The figure is a sectional view of a shock absorber that is an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Cylinder, 1a... Recessed part, 2... Piston rod, 2a... Flange part, 3... Permanent magnet (magnetism generating means), 3a... Magnetic sensing element (magnetic sensing means), 3b... Through hole, 4...Piston, 4
a...channel, 4b...groove, 5...holder, 5a...
...Fluid passage, 6...Spacer, 7...Retainer,
8... O-ring, 9... Packing, 10... Fluid, 11... Accumulator, 12... Coil spring, 13... Threaded portion.

Claims (1)

[Scope of utility model registration request] A cylinder made of a non-magnetic material and having a cylindrical shape with a bottom; a piston located within the cylinder and movable in the axial direction of the cylinder; a piston rod that moves together with the piston; and a fluid sealed within the cylinder. an accumulator that absorbs the volume change of the fluid; a magnetism generating means that is locked to the inner end of the piston rod in the cylinder and moves together with the piston; 1. A shock absorber comprising: a magnetic sensing means that is detachably fitted into a recess formed in such a manner as to detect magnetism generated by the magnetic generating means.