JPS61153031A - Hydraulic draft gear - Google Patents

Abstract

PURPOSE:To control damping force in multistage according to the running conditions by incorporating switch means capable of controlling the connection of passages connecting chambers on both sides of a piston in multistage in the internal end portion of a piston rod of a hydraulic draft gear. CONSTITUTION:A twin-tube hydraulic draft gear has a piston rod 14 movably inserted in an inside cylinder 12. A piston not shown is mounted on the end portion 15 of the piston rod 14. In this case, a hole for a coil is formed on the internal end portion of the piston rod 14, and the first and second passages 32, 34 are formed as a by-path. A core 44 is disposed in the hole 24, and the core 44 is provided with an axial through hole 46 and with the third and fourth passages 48, 50 connecting the first and second passages 32, 34. A plunger 56 deviated to a neutral position by springs 78, 80 is fitted in the above through hole 46, and slid to displace by controlling the electricity applied to coils 70, 72 wound round both ends of the core 44.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a hydraulic shock absorber, and particularly to a hydraulic shock absorber whose damping force can be adjusted from the outside.

(Prior art) The damping force of the hydraulic shock absorber installed in the suspension of an automobile affects ride comfort and handling stability. Although some products have been put into practical use that change the
The damping force is simply switched to two stages.

(Problems to be Solved by the Invention) In order to further improve steering stability while ensuring optimal riding comfort depending on the driving situation, it is necessary to switch the damping force to a higher number of stages.

The present invention provides a hydraulic shock absorber that makes this possible.

Incidentally, the damping force of the hydraulic shock absorber is adjusted by communicating or blocking a bypass, which is a liquid passage provided in a piston rod, with a plunger or the like. The adjustment mechanisms in this case can be roughly divided into those that electrically move the plunger and those that mechanically move or rotate the plunger. The present invention relates to the former.

In order to connect and disconnect the bypass by moving the plunger made of magnetic material electrically, that is, by using the attraction force generated in the coil, it is necessary to ensure that the plunger is not affected by the force of fluid flow through the bypass. It must remain in place and provide the necessary damping force.The present invention provides a hydraulic shock absorber that meets this need.

(Means for Solving the Problem) A hydraulic shock absorber according to the present invention is a piston rod having a hole for a coil and having an end near a chain hole as a piston attachment portion, the piston attachment portion being a piston attachment portion. a piston rod that extends beyond the hole and extends along the axial direction of the hole, and has a first passage that opens at an intermediate portion of the hole and a second passage that extends from the hole toward an outer circumferential surface; a through hole extending in the axial direction, a third passage communicating with the first passage and the through hole, and a fourth passage communicating with the second passage and the through hole, and disposed within the hole. a core, a plunger made of a magnetic material having a fifth passage capable of communicating with the third and fourth passages, and disposed movably in the axial direction within the through hole of the core; and a diameter of the plunger. a pair of coils disposed outward in the direction on both sides of the core of the hole, and a pair of coil springs disposed on both sides of the plunger for biasing the plunger toward a neutral position. include.

(Example) As shown in FIGS. 1 and 2, the hydraulic shock absorber 1O is
It includes a piston rod 14 movably disposed within the cylinder 12 .

In the illustrated example, the hydraulic shock absorber IO is of the so-called twin tube type, comprising a cylinder 12 and a shell 16 spaced apart from the cylinder 12. The cylinder 12 and shell 16 are connected to the rod guide 1 at the upper end.
8 and a ring nut 20, and at the lower end by the base valve case and pace cap. The piston rod 14 protrudes to the outside of the cylinder 12 in a liquid-tight state by a seal member 22 fixed to a ring nut 20. The above configuration itself is known and 1
Since it is not directly related to the present invention, detailed explanation will be omitted. Note that the present invention can also be implemented in a so-called monotube type hydraulic shock absorber that includes only a single cylinder.

The piston rod 14 has a hole z4 for a coil in a portion that will be located inside the cylinder 12. In the illustrated example, the piston rod 14 consists of a first portion 26 and a second portion 28, and the first portion 26 has a hole 27 cut out from the end surface.
However, the second portion 28 also has a hole 24 cut out from the end surface.
is provided.

The end 15 of the piston rod 14 near the bore 24 is designed as a mounting for a piston 30 (FIG. 2). A first passage 32 and a second passage 3 are provided in the piston rod 14.
4 is provided to form a bypass.

In the illustrated example, the first passage 32 includes a passage portion 36 extending beyond the piston mounting portion 15 in the axial direction from the end surface of the piston rod, a passage portion 37 extending obliquely from the passage portion 36 toward the outer peripheral surface, and a passage portion 37 and extending in the axial direction of the hole 24 to an intermediate portion of the hole;
The openings of the passage portion 37 and the passage portion 38, which are made up of two annular passage portions 39 and 40 provided at the hole 4, are sealed with plugs 42 and 43 after machining.

A second passage 34 extends from the hole 24 to the outer circumferential surface. As a result, as shown in FIG. 2, when the piston 30 is attached to the piston mounting portion 15, the liquid chambers A and B partitioned on both sides of the piston are connected to the port 4 provided in the piston 30.
2.43 and communicate via the first passage 32, the hole 24 and the second passage 34.

A core 4 made of magnetic material is disposed within the hole 24 of the piston rod 14.
4 is placed. The core 44 has a through hole 4 extending in the axial direction.
6, and a third passage communicating with the first passage 32 and the through hole 46.
In the illustrated example having a passageway 48 and a fourth passageway 50 communicating with the second passageway 34 and the through hole 46, the third passageway 48 communicates with the passageway portions 39, 40 of the first passageway, respectively. The fourth passageway 50 consists of a passageway section 52.53 leading into it, and the fourth passageway 50 consists of a passageway section 54.55.
5 communicates with the second passage 34 through annular grooves provided in the piston rod 14 and the core 44, respectively.

The plunger 56 is made of a magnetic material and has a through hole 4 in the core 44.
In the illustrated example, the plunger 56 is arranged axially movably within the plunger 58.
60, the member 58 is provided with an annular passage portion 59, the member 60 is provided with an annular passage portion 61, and the passage portion 59 in which the fifth passage 62 is formed is connected to the passage portion 52 of the core and the passage portion. 54, and passageway portion 61 communicates with passageway portions 53 and 55 of the core.

A pair of cores 64 and 66 made of magnetic material are arranged at intervals from the plunger 56 in the axial direction. These core 6
4.66 is abutted against the core 44 via a cylindrical spacer 68, and is held at a predetermined distance from the central core 44.

A pair of coils 70 are disposed on both sides of the central core 44 in the axial direction inside the hole 24 on the outside of the plunger 56 in the radial direction.
．． 72 is placed. Each coil is covered with a protective cover 74 and fitted into a spacer 68. In use, electricity is selectively supplied to one or the other coil via a lead wire 76 extending outside the piston rod 14.
Both coils are energized and de-energized together.

A pair of coil springs 78,80 are disposed on both sides of the plunger 56 in the axial direction, biasing the two members 58,60 that make up the plunger 56 toward a neutral position.In the illustrated example, the central core 44 Pin 82 is implanted in
Each member abuts this bin and is held in a neutral position. A flanged collar 84 made of a non-magnetic material is arranged at the end of each member of the plunger 56, and each coil spring presses each member of the plunger 56 via the collar 84.

Collar 84 prevents plunger 56 from becoming magnetized.

An O-ring is placed on the axially outer side of the two passage portions 52.53 of the central core 44, and the core 44, plunger 56, coil 70.72, and other parts are placed in the hole 24 of the piston rod 14. the first portion 26 and the second portion 26.
The piston rod 14 is constructed by fitting into the portion 28, caulking the end of the hole 24 to fix each component, and welding the first portion 26 and the second portion 28.

Piston 30, valve body 90.92, in piston mounting part 15,
A coil spring 94 and the like are arranged, and a nut 96 is screwed to connect the piston 30 to the piston rod 14.

(Function of the embodiment) The hydraulic shock absorber lO is installed in the suspension of an automobile, the shell 16 is attached to the suspension arm, and the piston rod 1 is attached to the suspension arm.
4 are connected to the vehicle body respectively.

The coils 70 and 72 are energized by manual operation by the driver or by automatic operation by a CPU, that is, a computer, which makes decisions based on signals from various sensors.

When the plunger 56 is in the neutral position shown, the liquid chamber A,
Since B communicates with the outside of the port 42.43 of the piston 32 through all the passage sections of the first to fifth passages, when the piston 30 moves, the amount of liquid passing through the port 42.43 is small. Therefore, the hydraulic damper lO generates a small damping force.

When the upper coil 70 or the lower coil 72 is energized and the member 58 or 60 of the plunger 56 is moved upward or downward, the liquid chambers A and B move through one passage portion 59 or 61 of the plunger 56. The hydraulic shock absorber 10 produces an intermediate damping force.

When the upper coil 70 and the lower coil 72 are energized,
The upper member 58 is moved upwardly and the lower member 60 is moved downwardly, so that the passage portions 59.61 are moved into the third passageway 48.
Since it is separated from the fourth passage 50, the liquid chambers A and B communicate only through the boats 42 and 43 of the piston 30, and the hydraulic shock absorber IO generates a large damping force. When each coil is de-energized, each member 58,60 of the plunger 56 returns to its neutral position under the action of the coil spring 78,80.

(Effect of the invention) According to the present invention, the following effects can be obtained.

The number of damping force switching stages can be increased. That is, by configuring each passage with two passage parts as shown in the figure, three stages of switching are possible. Further, for example, by changing the cross-sectional area of the two passage portions of the plunger passage, four-stage switching becomes possible. the result,
This makes it easy to ensure optimal ride comfort depending on the driving situation and further improve handling stability.

Since the plunger is not subjected to the axial fluid flow force when the piston moves, the plunger can be reliably held in place even when the piston moves at high speed, and the damping force of the hydraulic shock absorber can be maintained within the intended range.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the main part of the piston rod, and FIG. 2 is a sectional view showing the main part of the hydraulic shock absorber. 10: Hydraulic shock absorber, 12 Niji cylinder, 14: Piston rod, 24: Hole, 32: First passage, 34: Second passage, 44: Co7
, 48: third passage, 50: fourth passage,
58 Nibrangiya, 62: 5th passage, 70.7
2: Coil, 78.80: Coil spring. Agent Patent Attorney Nobuyuki Matsunaga Figure 1

Claims (1)

[Claims] A piston rod having a hole for a coil and having a piston mounting portion at an end near the hole, extending beyond the piston mounting portion and outside the hole in the axial direction of the hole,
a piston rod having a first passage that opens at an intermediate portion of the hole and a second passage that extends from the hole toward an outer circumferential surface; a through hole that extends in the axial direction and communicates with the first passage and the through hole; and a fourth passage communicating with the second passage and the through hole, and a core disposed within the hole, and a fifth passage communicating with the third and fourth passages. a plunger made of a magnetic material and arranged to be movable in the axial direction within the through hole of the core; A hydraulic shock absorber including a pair of coils respectively disposed and a pair of coil springs disposed on opposite sides of the plunger for biasing the plunger toward a neutral position.