JPH0612849U - Position sensor structure of hydraulic shock absorber - Google Patents

Abstract

(57) [Summary] [Purpose] To accurately detect the stroke position of the piston of the hydraulic shock absorber. A rod-shaped sensor body 27 in which a position detecting sleeve 25 made of a non-magnetic material is erected on the bottom bolt 16, the tip end side is inserted into the rod end 7, and the hollow rod 6 is attached to the rear end portion. Is inserted into the position detection sleeve 25, and the extension portion 7 having the same inner diameter is attached to the upper end portion of the rod end 7.
By forming a, the inner peripheral surface of the rod end 7 having a constant diameter is positioned over the entire measurement range of the sensor body 27.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a position sensor structure for a hydraulic shock absorber used in a vehicle or the like.

[0002]

[Prior art]

 As a conventional hydraulic shock absorber, as shown in FIG. 3, a hollow rod 102, which is a piston rod, is inserted into a cylinder 101 from above, and a hollow rod end 103 is attached to the tip end of the hollow rod 102 to form a rod end. A piston 104, which is in sliding contact with the inner peripheral surface of the cylinder 101, is fixed to 103, and oil passages 105 and 106 for generating damping force and valves 107 and 108 for opening and closing these oil passages 105 and 106 are attached to this piston 104. .

A position detecting sleeve 110 made of a non-magnetic material in the cylinder 101 is erected and inserted into the rod end 103, and a rod-shaped sensor body 111 attached to the hollow rod 102 is inserted into the position detecting sleeve 110. The vertical movement of the hollow rod 102 causes the sensor body 111 to move in and out of the position detection sleeve 110, thereby changing the amount of opposition to the sleeve 110 that blocks the magnetic field generated from the sensor body 111. I am trying to detect the position.

[0004]

[Problems to be solved by the device]

 However, in the above-mentioned position sensor structure of the hydraulic shock absorber, since the inner diameters of the hollow rod located around the sensor body and the rod end attached to its tip end are different, a uniform magnetic field generated from the sensor body is generated. Will be affected differently, and the proportionality between the displacement of the sensor body and the output characteristics will disappear.

[0005]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, according to the present invention, a position detection sleeve is inserted into a rod end attached to a distal end of a hollow rod, and a rod-shaped sensor body having a base end attached to the hollow rod is inserted into the position detection sleeve. The rod end inner surface of the hydraulic shock absorber that detects the stroke position by blocking the magnetic field generated from the sensor body with the position detection sleeve on the outer circumference of the sensor body over the entire measurement range of the sensor body. Positioned.

[0006]

[Action]

 Since the rod end inner peripheral surface is located over the entire measurement range of the sensor body, the influence exerted on the magnetic field generated by the sensor body becomes even, and the proportional characteristic of the displacement amount of the sensor body and the output characteristic can be secured.

[0007]

【Example】

 Embodiments of the present invention will be described below with reference to the accompanying drawings. Here, FIG. 1 is a cross-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 cross-sectional view of a main part of FIG.

The cylinder 1 is fitted with an end cap 2 at the upper end and a bottom cap 3 at the lower end to close them, and the cylinder 1 is closed from above by a rod guide 4 and an oil seal 5. The hollow rod 6 is inserted, and the 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 attached to the rod end 7, and a compression side oil passage 9 (FIG. 2) and an extension side oil passage 10 are formed in the piston 8 and A compression side valve 11 for opening and closing the compression 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 on the bottom of the cylinder 1, a bottom bolt 16 is screwed onto the bottom valve case 15, and a bottom check valve seat 17 is attached to the bottom bolt 16. An oil passage 18 on the compression side and an oil passage on the extension side (not shown) are formed in the bottom check valve seat 17, and a valve 20 for opening / closing the oil passage 18 on the compression side and a valve 21 for opening / closing the valve on the extension side are attached. .

In addition, at the bottom of the bottom of the bottom valve case 15 at the bottom of the cylinder 1, a free piston 22 that slidably contacts the inner peripheral surfaces of the cylinder 1 and the bottom cap 3 in order to compensate for the volume change due to the forward and backward movement of the hollow rod 6. Is 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 25 a can be rotated and can move in parallel, and the tip end side of this position detecting sleeve 25 is inside the rod end 7. The bush 26, which is slidably contacted with the outer peripheral surface of the position detecting sleeve 25, is fitted on the inner peripheral surface of the tip end portion of the rod end 7.

Then, a rod-shaped sensor body 27 having a rear end portion attached to the hollow rod 6 is inserted into the position detection sleeve 25. Further, since the inner diameters of the hollow rod 6 and the rod end 7 are different, the extension portion 7a having the same inner diameter is formed at the upper end portion of the rod end 7 so that the inside of the rod end 7 is covered over the entire measurement range of the sensor body 27. The perimeter is located.

In the hydraulic shock absorber configured as described above, when the hollow rod 6 moves up and down, damping force is generated by the oil passage of the piston 8 and the valve mechanism, and the oil passage of the bottom check valve seat 17 is generated. Also, a damping force is generated by the valve mechanism, and the free piston 22 moves up and down to compensate for the volume change accompanying the entry or exit of the hollow rod 6.

The sensor body 27 moves in and out of the position detecting sleeve 25 as the hollow rod 6 moves up and down, thereby blocking the magnetic field generated by the sensor body 27. Since the amount of opposition to and changes, it is possible to detect the stroke position of the hollow rod 6, that is, the piston 8.

In this case, the rod end 7 located around the sensor body 27 forms an extending portion 7 a, and the rod end 7 has a uniform inner diameter on the outer circumference over the entire measurement region of the sensor body 27. Since the peripheral surface is located, the influence on the magnetic field generated from the sensor body 27 becomes uniform. Therefore, the proportional characteristic of the displacement amount of the sensor body 27, that is, the stroke amount and the output characteristic can be secured, and the detection accuracy is improved.

[0017]

[Effect of device]

 As described above, according to the present invention, since the rod end inner peripheral surface having a constant diameter is positioned over the entire measurement range of the sensor body, the influence exerted on the magnetic field generated by the sensor body becomes uniform. The proportionality between the displacement amount of the sensor body and the output characteristic can be secured, and the detection accuracy of the stroke position of the piston of the hydraulic shock absorber is improved.

[Brief description of 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.

2 is a cross-sectional view of the main part of FIG.

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 part, 8 ... piston, 16 ... bottom bolt, 22
... Free piston, 25 ... Position detection sleeve, 27 ... Sensor body.

Claims (1)

[Scope of utility model registration request] 1. A rod-shaped sensor body in which a position detecting sleeve made of a non-magnetic material standing upright in a cylinder is inserted into a rod end attached to a distal end of a hollow rod, and a base end is attached to the hollow rod. In a hydraulic shock absorber which is inserted into the position detecting sleeve and detects the stroke position by blocking the magnetic field generated from the sensor main body with the position detecting sleeve, the rod end inner peripheral surface is measured within the measuring range of the sensor main body. The position sensor structure of the hydraulic shock absorber is characterized in that the entire area is located on the outer circumference of the sensor body.