JP2560743Y2 - Hydraulic shock absorber position sensor structure - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position sensor structure of a hydraulic shock absorber used for a vehicle or the like.

[0002]

2. Description of the Related Art As a conventional hydraulic shock absorber, as shown in FIG. 3, a hollow rod 102 serving as a piston rod is inserted from above into a cylinder 101, and a hollow rod end 103 is attached to the tip of the hollow rod 102. And the piston 1 sliding on the inner peripheral surface of the cylinder 101 with the rod end 103
The piston 104 is provided with oil passages 105 and 106 for generating damping force and valves 107 and 108 for opening and closing the oil passages 105 and 106.

Then, a position detecting sleeve 110 made of a non-magnetic material in the cylinder 101 is erected and the rod end 10 is mounted.
3, the rod-shaped sensor body 111 attached to the hollow rod 102 is inserted into the position detecting sleeve 110, and the vertical movement of the hollow rod 102 causes the sensor body 11 to move.
The stroke position is detected by changing the amount of movement of the sensor body 111 into and out of the position detection sleeve 110 and the amount of opposition to the sleeve 110 that blocks the magnetic field generated from the sensor main body 111.

[0004]

However, in the above-described position sensor structure of the hydraulic shock absorber, since the inner diameter of the hollow rod located around the sensor body and the rod end attached to the tip end thereof are different, The uniform magnetic field generated from the main body is affected differently, and the proportional characteristic between the displacement amount of the sensor main body and the output characteristic is lost.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a rod-like structure in which a position detecting sleeve is inserted into a rod end mounted on a distal end of a hollow rod, and a base end is mounted in the hollow rod. A sensor body is inserted into the position detecting sleeve, and the magnetic field generated from the sensor body is blocked by the position detecting sleeve to detect a stroke position. The inner peripheral surface of the rod end of the hydraulic shock absorber is measured by the sensor body. It was located on the outer periphery of the sensor body over the entire range.

[0006]

[Function] Since the inner peripheral surface of the rod end is located over the entire measurement range of the sensor main body, the influence on the magnetic field generated from the sensor main body becomes uniform, and the proportional characteristic between the displacement amount of the sensor main body and the output characteristic is secured. it can.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the accompanying drawings. Here, FIG. 1 is a sectional view of a hydraulic shock absorber to which the position sensor structure according to the present invention is applied, and FIG. 2 is an enlarged sectional view of a main part of FIG.

The cylinder 1 is closed by mounting an end cap 2 at an upper end and a bottom cap 3 at a lower end, and is closed in the cylinder 1 from above through a rod guide 4 and an oil seal 5. The rod 6 is inserted, and a hollow rod end 7 is screwed to the lower end of the hollow rod 6.

A piston 8 which is in sliding contact with the inner peripheral surface of the cylinder 1 is mounted on the rod end 7. A compression-side oil passage 9 (FIG. 2) and an extension-side oil passage 10 are formed in the piston 8, A compression side valve 11 for opening and closing the side oil passage and an extension side valve 12 for opening and closing the extension side oil passage 10 are attached.

A bottom valve case 15 is provided at the bottom inside the cylinder 1, a bottom bolt 16 is screwed into the bottom valve case 15, and a bottom check valve seat 17 is mounted on the bottom bolt 16. A valve 2 for forming a compression-side oil passage 18 and an extension-side oil passage (not shown) in the bottom check valve seat 17 to open and close the compression-side oil passage 18
A valve 21 for opening and closing the 0 and extension side valves is mounted.

On the inner bottom of the cylinder 1, a free piston 22 slidingly contacting the inner peripheral surface of the cylinder 1 and the bottom cap 3 is provided below the bottom valve case 15 in order to compensate for a change in volume due to the forward and backward movement of the hollow rod 6. Are slidably fitted to define a gas chamber SG.

Further, a position detecting sleeve 25 made of a non-magnetic material is erected on the bottom bolt 16 so that the spherical end portion 25a can be rotated and moved in parallel. A bush 26 that slides on the outer peripheral surface of the position detecting sleeve 25 is fitted on the inner peripheral surface of the distal end portion of the rod end 7.

A rod-shaped sensor body 27 having a rear end attached to the hollow rod 6 is inserted through the position detecting sleeve 25. Further, since the inner diameter of the hollow rod 6 and the inner diameter of the rod end 7 are different from each other, an extension 7a having the same inner diameter is formed at the upper end of the rod end 7 so that the inner circumference of the rod end 7 is extended over the entire measurement range of the sensor body 27. The face is located.

In the hydraulic shock absorber constructed as described above, the piston 8 is moved up and down by the hollow rod 6.
A damping force is generated by the oil passage and the valve mechanism of the bottom check valve seat 17 and a damping force is generated by the oil passage and the valve mechanism of the bottom check valve seat 17. Compensates for volume changes.

The sensor body 27 enters and exits the position detecting sleeve 25 as the hollow rod 6 moves up and down. , The stroke position of the hollow rod 6, that is, the piston 8, can be detected.

In this case, the rod end 7 located around the sensor main body 27 forms an extended portion 7a, and the inner end of the rod end 7 having a uniform inner diameter on the outer periphery thereof over the entire measurement region of the sensor main body 27. Since the surface is located,
The effect on the magnetic field generated from the sensor body 27 becomes uniform. Therefore, a proportional characteristic between the displacement amount, that is, the stroke amount of the sensor main body 27 and the output characteristic can be secured, and the detection accuracy is improved.

[0017]

[Effects of the Invention] As described above, according to the present invention,
Since the inner peripheral surface of the rod end with a constant diameter is located over the entire measurement range of the sensor body, the effect on the magnetic field generated from the sensor body becomes uniform, and the displacement amount of the sensor body and the output characteristic are proportional. Characteristics can be secured, and the accuracy of detecting the stroke position of the piston of the hydraulic shock absorber is improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a hydraulic shock absorber to which a position sensor structure according to the present invention is applied.

FIG. 2 is a sectional view of a main part of FIG. 1;

FIG. 3 is a sectional view of a conventional hydraulic shock absorber;

[Explanation of symbols]

1 ... cylinder, 6 ... hollow rod, 7 ... rod end, 7
a: extension, 8: piston, 16: bottom bolt, 22
... free piston, 25 ... position detection sleeve, 27 ... sensor body.

Claims (1)

(57) [Scope of request for utility model registration] 1. A rod-shaped sensor main body having a base end mounted inside a hollow rod, wherein a position detecting sleeve made of a non-magnetic material erected in a cylinder is inserted into a rod end mounted on a distal end of the hollow rod. In a hydraulic shock absorber that is inserted into the position detection sleeve and detects a stroke position by blocking a magnetic field generated from the sensor main body with the position detection sleeve, the inner peripheral surface of the rod end is measured in a measurement range of the sensor main body. A position sensor structure for a hydraulic shock absorber, wherein the position sensor structure is located on the outer periphery of the sensor body over the entire area.