JPS6140571Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a hydraulic shock absorber for a vehicle that adjusts damping force and vehicle height.

As a hydraulic shock absorber for a vehicle, a so-called vehicle height adjustment means adjusts the gas pressure to raise or lower the vehicle body according to changes in the number of passengers or the loaded load.
The present applicant has developed a vehicle that is equipped with means to adjust the damping force according to driving conditions in order to prevent rolling and longitudinal movement (nose dive and squat) of the vehicle, thereby improving ride comfort and running stability. It has been proposed as Utility Application No. 157915 (1983).

This will be explained with reference to FIG.

This is applied to a single cylinder hydraulic shock absorber.
1 is a cylinder, 2 is a piston rod, and the inside of the cylinder 1 is defined into an upper oil chamber A and a lower oil chamber B by a freely slidable piston 3. 4 is a cover fixed to the piston rod 3, and between the lower edge of the cover 4 and the upper end of the cylinder 1,
Rubber tubes 5 are stretched through rings 6 and 7, respectively, and together with the cover 4 form an air chamber C. This rubber tube 5 has a U-shaped cross section, and when the pressure in the air chamber C rises, the surface in contact with the cylinder 1 gradually separates from the bottom and the cover 4
It is starting to rise as well.

Reference numeral 8 denotes an operating rod rotatably inserted into the through hole 9 of the piston rod 2, and a regulating valve 1 is installed at the lower end of the operating rod.
0 is fixed. A plurality of orifices 11 having different diameters are formed radially from the inner hole of the regulating valve 10, and the upper oil chamber A and the lower oil chamber B are
A port 12 formed in the lower side of the piston rod 2 communicates with the orifice 11 of the regulating valve 10 and through the through hole 9 of the piston rod 2.

In this hydraulic shock absorber, the upper end of the piston rod 2 is fixed to a part of the vehicle body 13, and the bracket 14 at the lower end of the cylinder 1 is connected to the axle side.

The upper end of the operating rod 8 is connected to the piston rod 2.
The air chamber C is connected to the output shaft of a rotary solenoid 15 fixed to the vehicle body, while the air chamber C is connected to a supply/discharge valve (three-way solenoid valve) 1 fixed to the vehicle body through an air pipe 30.
6 to a pressure tank 17.

The above rotary solenoid 15 and supply/discharge valve 1
6 are both controlled in operation by signals from a control device 18, and the control device 18 includes sensors such as a load sensor 19, a vehicle speed sensor 20, a steering sensor 21, a brake sensor 22, an accelerator sensor 23, and a road surface sensor 24 that detect driving conditions. Based on these, the control device 18 operates the rotary solenoid 15 and the supply/discharge valve 16 so as to obtain the optimal vehicle height and damping force at that time.

For example, during pressure-side operation when the piston rod 2 enters the inside of the cylinder 1, the hydraulic oil from the lower oil chamber B, which contracts, is transferred to the upper oil chamber A, which expands as the piston 3 descends, to the damping valve 27 and the piston rod 2.
through the through hole 9, the orifice 11 and the port 12 of the regulating valve 10. At this time, the resistance given to the hydraulic oil flowing through the orifice 11 generates an appropriate damping force until the damping valve 27 opens.

The rotary solenoid 15 is driven and the regulating valve 10 is rotated via the operating rod 8 to open the orifice 1.
For example, if the area of orifice 1 is changed,
The smaller the area of 1, the higher the damping force.

Note that the hydraulic oil corresponding to the volume entered by the piston rod 2 pushes the free piston 29 and compresses the gas chamber D. On the contrary, during the expansion side operation, the hydraulic oil from the upper oil chamber A flows into the lower oil chamber B through the orifice 11, similar to the damping valve 28, and similarly generates a damping force.

On the other hand, open the supply/discharge valve 16 and
When the air in the pressure tank 17 charged in step 5 is led to the air chamber C, the volume of the air chamber C increases, the cylinder 1 is lowered relative to the piston rod, and the vehicle height can be increased. Conversely, if the air in the air chamber C is released to the atmosphere through the supply/exhaust valve 16, the vehicle height will be lowered.

When the vehicle is empty and has a light load, the control device 18 receives the detection signal from the load sensor 19 and sends a switching signal to the supply/exhaust valve 16 to release a portion of the air in the air chamber C to the atmosphere and adjust the height to the optimal standard vehicle height. However, when the vehicle speed is high, the vehicle height is lowered to maintain high-speed driving stability. On the other hand, when the vehicle is loaded or when driving at low speed, high pressure air from the pressure tank 17 charged by the compressor 25 is supplied to the air chamber C via the supply/discharge valve 16 to maintain the standard vehicle height. to prevent the hydraulic shock absorber from bottoming out.

On the other hand, when lateral acceleration or longitudinal acceleration is applied to the vehicle body, such as when the vehicle is cornering, suddenly braking, or suddenly starting, the left and right hydraulic shock absorbers and the front and rear hydraulic shock absorbers receive compression force, causing the piston rod 2 to suddenly move into the cylinder. 1, causing the vehicle body to roll and nose dive.

In such a case, the steering sensor 21, brake sensor 22, or accelerator sensor 23
Upon receiving the detection signal, the control device 18 outputs an output signal to the rotary solenoid 15 to operate it, rotates the regulating valve 10 via the operating rod 8,
The orifice 11 facing 2 is changed to one with a smaller opening area to throttle the hydraulic oil and increase the compression side damping force to play the role of anti-roll and anti-nose dive.

Furthermore, when a predetermined high speed is reached or when driving on an uneven, rough road, the control device 18 operates the rotary solenoid 15 in response to detection signals from the vehicle speed sensor 20 and road surface sensor 24 to increase the damping force. This improves driving stability.

However, in this case, since the air pipe 30 that supplies high pressure air from the supply/discharge valve 16 to the air chamber C is directly connected to the cover 4, the air pipe 30
However, there were problems in that it was easily damaged by external impacts such as flying stones, and it was difficult to assemble.

The purpose of the present invention is to improve the durability and ease of assembly of air piping.

Therefore, the present invention utilizes the gap formed between the piston rod and the operating rod to form a passage that communicates with the interior of the cover from the air introduction passage that passes through the movable shaft of the solenoid at the top of the piston rod. To provide a hydraulic shock absorber which supplies air to an air chamber.

Hereinafter, an embodiment of the present invention will be described based on FIGS. 2 and 3, and the same reference numerals will be used for substantially the same parts as in FIG. 1.

An operating rod 8 is inserted through the piston rod 2 so as to be freely rotatable.

A closed air passage 31 is formed in the gap around the outer periphery of the operating rod 8.

On the other hand, a rotary solenoid 15 is fixed to the upper part of the piston rod 2 by being clamped by two nuts 34 and 35 whose bracket 33 is screwed onto the outer periphery of the rod.

Movable axis of rotary solenoid 15 (rotor axis)
The tip of the movable shaft 36 is inserted into the through hole 9 of the piston rod 2, and its periphery is sealed with a sealing material (O ring) 32, and passes through the movable shaft 36 in the axial direction to form an air introduction path 37. This air introduction path 37 is communicated with the air passage 31. A slit 38 is formed at the shaft end of the movable shaft 36, and a protrusion 39 at the tip of the operating rod 8 engages with the slit 38, thereby transmitting the rotation of the movable shaft 36 to the operating rod 8.

Note that a gap h is formed between the tip of the protrusion 39 and the bottom of the slit 38 to allow air to pass therethrough. The solenoid 15 is a tandem type rotary solenoid, and includes two coils 44 and 45 and a rotor 46, and the rotor 46 rotates by a predetermined angle left and right when the coils 44 and 45 are energized.

Furthermore, a plug 48 that connects to an air pipe 47 is fixed to the upper end of the movable shaft 36 .

On the other hand, the piston rod 2 has a lower side passage 41 located inside the cover 4 and communicating with the air passage 31.
is formed, and as a result, a pressure tank 1 is formed in the air chamber C.
It is designed to be able to supply high pressure air from 7.

Note that 43 is a bump rubber, and a side passage 41 is opened on the inner periphery of the bump rubber, and normally air is fed through a gap formed between the bump rubber and the piston rod 2.

Since the present invention is configured in this manner, when air is supplied from the pressure tank 17 for vehicle height adjustment, the air introduction path 3 of the movable shaft 36 of the solenoid 15 is
7, the air chamber C from the side passage 41 via the air passage 31 in the gap between the piston rod 2 and the operating rod 8.
air can be pumped into.

Therefore, since the air piping is not exposed to the outside of the vehicle body as in the conventional case, there is no risk of it being damaged by flying stones from the road surface.

Furthermore, since the operating rod 8 and the air passage 31 are coaxial, the ease of assembly to the piston rod 2 is good, and productivity is greatly improved, especially compared to the conventional arrangement in which they are arranged separately.

Note that the operating rod 8 is a rotary solenoid 15.
The movable shaft 36 rotates left and right, thereby changing the area of the orifice 11 of the regulating valve 10 and adjusting the damping force. In addition, in a type in which the movable shaft 36 of the rotary solenoid 15 moves up and down slightly as it rotates, it is necessary to provide an axial gap between the engaging portion of the slit 38 and the protrusion 39. The mutual lengths are set so that h will not be blocked by the axial movement of the movable shaft 36.

As described above, according to the present invention, the air passage passes through the movable shaft of the rotary solenoid and is formed using the gap between the piston rod and the operating rod, so the air passage is protected from flying stones from the outside. The air passage is completed at the same time as the operating rod and solenoid are assembled, so it is very easy to assemble and improves productivity.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a conventional device, FIG. 2 is a cross-sectional view showing an embodiment of the present invention, and FIG. 3 is an enlarged cross-sectional view of line - in FIG. 2. 1...cylinder, 2...piston rod, 3...
Piston, 4: Cover, 5: Rubber tube, 8: Operating rod, 9: Through hole, 10:
Regulating valve, 15... rotary solenoid, 16...
Supply and exhaust valve, 17: pressure tank, 18: control device, 31: air passage, 33: bracket,
36: movable shaft; 37: air inlet passage; 38:
Slit, 39...protrusion, 47...air pipe, 3
6, 41: bypass, A, B: upper and lower oil chambers, C:
Air chamber.

Claims (1)

[Scope of utility model registration request] The upper and lower oil chambers are formed through a piston that is slidably housed in the cylinder, and the operating rod is rotatably inserted through the piston rod. While the area of the communication passage is variable, an air chamber is formed by covering the outside of the cylinder with a cover and an elastic tube, and the cover is connected to the protruding part of the piston rod, so that the piston rod can be moved relative to each other depending on the amount of air supplied to the air chamber. In a hydraulic shock absorber designed to be displaced, a solenoid is attached to the tip of a piston rod, a movable shaft of the solenoid is coaxially engaged with the operating rod, and an air passage is formed in an annular gap between the piston rod and the operating rod. A hydraulic shock absorber, characterized in that the air passage is communicated with an air introduction passage passing through the movable shaft in the axial direction, and the air passage is communicated with the air chamber via a side passage provided in the piston rod.