JPH10184761A - Damping force adjusting type hydraulic shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent foreign matter from invading the fluid chamber of a solenoid in which a movable member is arranged. SOLUTION: A piston 5 linked to a piston rod 6 is fitted so as to be capable of sliding in a cylinder 2 filled with oil liquid, a damping force generating mechanism 26 is fitted at the side surface part of the cylinder 2, and the damping force is adjusted by moving the spool 50 of a spool valve 35 by a proportional solenoid 36. A movable iron core 46 is disposed in the oil chamber 45 of the proportional solenoid 36, a flexible diaphragm 57 is fitted onto an operating rod 49. The oil chamber 45 and an oil passage through which the oil liquid flows by expanding and contracting the piston rod 6, are blocked by the diaphragm 57, and the oil chamber 45 is filled with the oil liquid. By the diaphragm 57, it is possible to prevent foreign matter such as worn powder generated on oil passage side from invading the oil chamber 45. The vibration such as dither vibration of the movable iron core 46 is softened by the diaphragm 57, thus it is possible to reduce noise.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a damping force-adjustable hydraulic shock absorber mounted on a suspension system of a vehicle such as an automobile.

[0002]

2. Description of the Related Art A hydraulic shock absorber mounted on a suspension system of a vehicle such as an automobile is provided with a damping force that can be appropriately adjusted according to road surface conditions, running conditions, and the like in order to improve ride comfort and steering stability. There is a damping force adjustable hydraulic shock absorber.

In general, a damping force adjusting type hydraulic shock absorber is slidably fitted with a piston connected to a piston rod in a cylinder filled with an oil liquid, and is generated by movement of the piston as the piston rod expands and contracts. The flow of the oil liquid is controlled by an orifice, a disk valve or the like to generate a damping force, and the damping force is adjusted by changing the passage area of the oil liquid by a damping force adjusting valve. Some damping force adjusting type hydraulic shock absorbers switch a damping force characteristic in accordance with energization of a coil by moving a valve element of a damping force adjusting valve by a solenoid.

[0004] In general, a solenoid mounted on a damping force adjusting type hydraulic shock absorber is provided with an oil immersion in order to reduce the effect of oil pressure acting on a movable iron core (movable member) and reduce its driving force. It has a structure. That is, the movable iron core is arranged in the oil chamber of the solenoid that communicates with the passage of the oil liquid, and the chambers formed at both ends of the movable iron core in the oil chamber are connected to each other. With this configuration, the pressure of the oil liquid generated by the expansion and contraction of the piston rod acts on both ends of the movable iron core and is balanced, so that no thrust due to the oil liquid pressure is generated and the driving force of the movable iron core can be reduced. it can.
Further, a change in the volume of the oil liquid in the oil chamber due to a change in the volume of the oil chamber and a change in temperature due to the movement of the movable core can be absorbed by a reservoir or the like on the cylinder side.

[0005]

However, in the above-described damping force-adjustable hydraulic shock absorber having the above-mentioned conventional solenoid,
There are the following problems.

Since the oil chamber of the solenoid is communicated with the passage of the oil liquid, foreign matters such as abrasion powder generated on the passage side of the oil liquid (damping force generating mechanism or the like) enter the oil chamber of the solenoid and move. There is a possibility that the solenoid may adhere to the sliding portion of the iron core and hinder the smooth operation of the solenoid. At this time, the sliding part (side part) of the movable core
Since the metal powder also serves as a magnetic path, metal powder is easily adsorbed.

In general, the oil chamber of the solenoid has a complicated shape, so that it is difficult to release air in the production process. In addition, the flow of the oil liquid hardly occurs in the oil chamber. It is unlikely that air will escape naturally. If air bubbles remain in the oil chamber of the solenoid, the dynamic pressure balance acting on both ends of the movable iron core may be disrupted, and vibration or the like may occur, preventing smooth movement of the movable iron core.

Further, when assembling the solenoid to the hydraulic shock absorber main body, there is a possibility that foreign matter such as burrs generated in a screw portion or the like may remain in the oil chamber of the solenoid, and it is difficult to control the cleanliness inside the solenoid. It is.

The present invention has been made in view of the above points, and has as its object to provide a damping force-adjustable hydraulic shock absorber that prevents foreign matter from entering the oil chamber of a solenoid.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a cylinder filled with an oil liquid, a rod that expands and contracts with respect to the cylinder, and a flow of the oil liquid caused by expansion and contraction of the rod. Damping force provided in the oil passage, a damping force adjusting valve that controls the flow of the oil liquid to adjust the damping force, and a solenoid that drives a valve element of the damping force adjusting valve. In the adjustable hydraulic shock absorber, the solenoid includes:
A casing forming a fluid chamber in which a fluid is sealed, a coil provided in the casing, and a slidably disposed coil chamber for driving the valve element in accordance with a current supplied to the coil; A movable member, and a flexible diaphragm for separating the oil passage and the fluid chamber is provided between the oil passage and the fluid chamber.

With this configuration, the fluid of the solenoid is isolated from the oil passage by the diaphragm, so that foreign matter generated on the oil passage side does not enter the fluid of the solenoid. Further, a change in the volume of the fluid of the solenoid accompanying the sliding of the movable member is transmitted to the oil passage side by bending the diaphragm.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings.

As shown in FIG. 2, the hydraulic shock absorber 1 according to the present embodiment has a double cylinder structure in which an outer cylinder 3 is provided outside a cylinder 2. 3, a reservoir 4 is formed. A piston 5 is slidably fitted in the cylinder 2, and the piston 5 defines the inside of the cylinder 2 into two chambers, an upper cylinder chamber 2a and a lower cylinder chamber 2b.

One end of a piston rod 6 (rod) is connected to the piston 5 by a nut 7, and the other end of the piston rod 6 passes through the cylinder upper chamber 2a and the upper end of the cylinder 2 and the outer cylinder 3. Rod guide 8 mounted on
And is extended through the seal member 9 to the outside of the cylinder 2. At the lower end of the cylinder 2, there is a cylinder lower chamber.
A base valve 10 that partitions the reservoir 2b from the reservoir 2 is provided. An oil liquid is sealed in the cylinder 2, and an oil liquid and a gas are sealed in the reservoir 4.

The piston 5 has an oil passage 11 communicating between the cylinder upper and lower chambers 2a and 2b, and a cylinder lower chamber 2b of the oil passage 11.
A check valve 12 is provided to allow the flow of the oil liquid from the side to the cylinder upper chamber 2a side. The base valve 10 has an oil passage 13 for communicating the cylinder lower chamber 2b with the reservoir 4, and a check valve 14 for permitting the flow of oil from the reservoir 4 side of the oil passage 13 to the cylinder lower chamber 2b. Is provided.

A substantially cylindrical passage member 15 is fitted around the outer periphery of the central portion of the cylinder 2. An upper tube 16 is fitted on the upper outer periphery of the cylinder 2 and connected to the passage member 15 to form an annular oil passage 17 with the cylinder 2. The annular oil passage 17 communicates with the cylinder upper chamber 2a via an oil passage 18 provided on a side wall near the upper end of the cylinder 2. A lower tube 19 is provided on the outer periphery of the lower part of the cylinder 2.
Are fitted and connected to the passage member 15, and the cylinder 2
To form an annular oil passage 20. The annular oil passage 20 communicates with the cylinder lower chamber 2b via an oil passage 21 provided on a side wall near the lower end of the cylinder 2.

A connection plate 22 is attached to the outer cylinder 3 so as to face the passage member 15. Connection pipes 23 and 24 communicating with the annular oil passages 17 and 20 are inserted and fitted into the connection plate 22 and the passage member 15, respectively. Further, the connection plate 22 is provided with a connection hole 25 communicating with the reservoir 4. The connecting plate 22 has a damping force generating mechanism.
26 are installed.

A connecting pipe is provided in the case 27 of the damping force generating mechanism 26.
23, 24 and oil passages 28, 29,
30 is provided, and in the case 27, the flow of the oil liquid between the oil passages 28 and 29 is controlled by controlling the flow of the oil liquid between the oil passages 28 and 29, and the flow of the oil liquid between the oil passages 29 and 30 is controlled. A contraction-side damping valve 32 for generating a damping force is provided. Here, the annular oil passage 17, the oil passage 18, the annular oil passage 20, the oil passage 21, the connection pipe 23, the connection pipe 24, the connection hole 25, the oil passage 28, the oil passage 29, and the oil passage 30 An oil passage through which the oil liquid flows is formed by expansion and contraction.

As shown in FIG. 1, the extension side damping valve 31 includes a main valve 33 (disk valve) which is a pilot type pressure control valve, a sub valve 34 (disk valve) which is a pressure control valve, and a variable flow control valve. And a spool valve 35 (damping force adjusting valve). By operating the spool valve 35 with the proportional solenoid 36 (solenoid) to change the flow area between the oil passages 28 and 29, the orifice characteristic (the damping force is substantially proportional to the square of the piston speed) is directly changed. Adjust and change the pressure in the pilot chamber 37 (back pressure of the main valve 33)
The valve characteristics (the damping force is almost proportional to the piston speed) can be adjusted by changing the valve opening pressure.
The sub-valve 34 obtains an appropriate damping force (valve characteristic) in a low piston speed range, that is, an orifice characteristic range, and optimizes the damping force characteristic.

The compression damping valve 32 includes a main valve 38 (disc valve) which is a pilot-type pressure control valve, a sub-valve 39 (disc valve) which is a pressure control valve, and a spool valve 35 shared with the extension damping valve 31. It is composed of
Like the extension side damping valve 31, the spool valve 35 is operated by the proportional solenoid 36 to change the flow passage area between the oil passages 29 and 30, thereby directly adjusting the orifice characteristics and the pressure in the pilot chamber 40. (Back pressure of the main valve 38) and the valve opening pressure of the main valve 35 to change the valve characteristics. The sub-valve 39 is for obtaining an appropriate damping force (valve characteristic) in a low-speed region of the piston speed, that is, an orifice characteristic region, so as to optimize the damping force characteristic.

In the proportional solenoid 36, fixed iron cores 41 and 42 also serving as a casing and a spacer 48 are connected to each other by means such as welding, and a cover 43A is provided outside the fixed iron cores 41 and 42. . The sleeve 43 of the spool valve 35 is screwed to the fixed core 41, and the fixed core 42
, A plug 44 is screwed in to form an oil chamber 45 (fluid chamber) inside the fixed iron cores 41 and 42 and the spacer 48. A movable iron core (movable member) is slidably guided in the oil chamber 45, and a coil 47 is arranged around the movable iron core 46. Here, fixed iron cores 41 and 42, spacer 48
A casing is constituted by the plug 44 and the plug 44.

An operating rod 49 is connected to one end of the movable iron core 46, and the distal end of the operating rod 49 is connected to the fixed iron core 41.
From the spool in the sleeve 43 of the spool valve 35
It is in contact with one end of 50 (valve element). The movable iron core
A movable member is constituted by 46 and the operating rod 49,
These are supported by bearings 51a and 51b made of fluororesin and the like mounted on the fixed iron cores 41 and 42.

The chambers 45a at both ends of the movable iron core 46 in the oil chamber 45,
45b is a through hole 52 penetrating the movable iron core 46 in the axial direction thereof.
Are in communication with each other. Chamber 45a has a fixed iron core 41
The oil passage 53 provided on the side of the oil passage, that is,
The one end side of the spool 50 in the sleeve 43 communicates with the chamber 54 side. The chamber 54 is communicated with an oil chamber 56 in the case 27, that is, an oil passage by an oil passage 55 provided in the sleeve 43.

An oil passage 53 and a chamber are provided near the tip of the operating rod 49.
A substantially disk-shaped flexible diaphragm 57 that blocks communication between the oil chamber and the oil chamber 45, that is, the oil passage, is provided.
The diaphragm 57 is made of a flexible material such as rubber, and has a fitting hole 58 at the center and a thick portion 59 at the outer periphery.
The diaphragm 57 has the thick portion 59 fitted into the circular recess 60 of the fixed core 41, and is pressed by the sleeve 43 screwed to the fixed core 41 to be joined to the fixed core 41. The operating rod 49 is inserted into the fitting hole 58, and the inner peripheral edge of the fitting hole 58 is
It is fitted into an outer peripheral groove 61 formed in 49 and connected to the operating rod 49. As shown in FIG. 3, an intermediate portion of the diaphragm 57 is
In the state of attachment to the fixed iron core 41 and the operating rod 49,
The cross-sectional shape is curved, so that the deformation resistance to the movement of the operating rod 49 is reduced, and the oil chamber 45 is easily deformed in response to a change in volume. In addition, the diaphragm 57
An oil liquid is sealed in the oil chamber 45 of the proportional solenoid 36 which is isolated from the oil passage side.

The proportional solenoid 36 moves the movable iron core 46 and the operating rod 49 to predetermined positions against the urging forces of the springs 62 and 63 in accordance with the current supplied to the coil 47, thereby positioning the spool 50. Thus, the respective flow passage areas of the spool valve 35 can be adjusted.

Next, the operation of the present embodiment configured as described above will be described.

During the extension stroke of the piston rod 6, the check valve 12 of the piston 5 is closed with the movement of the piston 5, and the oil liquid in the cylinder upper chamber 2a is pressurized.
17, flows through the connection pipe 23 to the oil passage 28 of the damping force generating mechanism 26, and further from the oil passage 28, the sub-valve 34, the spool valve 35,
The oil flows through the oil passage 29, the connection pipe 24, the annular oil passage 20, and the oil passage 21 to the cylinder lower chamber 2b. At this time, when the pressure on the cylinder upper chamber 2a side reaches the valve opening pressure of the main valve 33, the main valve 33 is opened, and the oil liquid flows directly from the sub-valve 34 to the oil passage 29. On the other hand, the oil liquid corresponding to the piston rod 6 having withdrawn from the cylinder 2 is supplied from the reservoir 4 to the check valve of the base valve 10.
14 is opened to flow to the lower cylinder chamber 2b.

Therefore, during the extension stroke, the piston speed is low and before the main valve 33 is opened, a damping force having an orifice characteristic is generated in accordance with the flow path area of the spool valve 35, and the piston speed increases, and the piston speed increases. When the pressure in the chamber 2a increases and the main valve 33 opens, a damping force having valve characteristics is generated according to the opening degree. The proportional solenoid 36 adjusts the flow path area of the spool valve 35 in accordance with the current supplied to the coil 47, thereby directly adjusting the orifice characteristics and reducing the pressure in the pilot chamber 37 (back pressure of the main valve 33). It can be varied to adjust the valve characteristics.

During the contraction stroke of the piston rod 6, the check valve of the piston 5 is moved with the movement of the piston 5.
12 is opened and the oil liquid in the lower cylinder chamber 2b flows directly into the upper cylinder chamber 2a through the oil passage 11 so that the cylinder upper and lower chambers 2b are opened.
Since the pressures 2a and 2b have substantially the same pressure, no oil liquid flows between the oil passages 28 and 29 of the damping force generating mechanism 26. On the other hand, as the piston rod 6 enters the cylinder 2, the check valve 14 of the base valve 10 closes, and the oil liquid in the cylinder 2 is pressurized to the extent that the piston rod 6 enters, and the cylinder lower chamber 2 b
Through the oil passage 21, the annular oil passage 20, and the connection pipe 24 to the oil passage 29 of the damping force generating mechanism 26, and further from the oil passage 29, through the sub-valve 39, the spool valve 35, the oil passage 30, and the connection hole 25. And flows to reservoir 4. At this time, the cylinder upper and lower chambers 2a, 2b
When the pressure on the side reaches the opening pressure of the main valve 38, the main valve 38 is opened and the oil liquid flows directly from the sub-valve 39 to the oil passage 30.

Therefore, during the contraction stroke, the piston speed is low and before the main valve 38 is opened, a damping force having an orifice characteristic is generated according to the flow path area of the spool valve 35, the piston speed increases, and the cylinder When the pressure in the chambers 2a and 2b increases and the main valve 38 opens, a damping force having valve characteristics is generated according to the opening degree. And the proportional solenoid 36
The orifice characteristics are directly adjusted by adjusting the flow path area of the spool valve 35 in accordance with the current supplied to the coil 47, and the pressure in the pilot chamber 40 (back pressure of the main valve 38) is changed. Can be adjusted.

In this case, depending on the position of the spool 50 of the spool valve 35, between the expansion-side oil passages 28 and 29 and the contraction-side oil passage
The sleeve 43 is designed so that the flow path area between 29 and 30 is large when one is large and the other is small when one is small.
By arranging each port and the land of the spool 50, a combination of different types of damping force characteristics on the extension side and the contraction side (for example, the extension side is hard and the contraction side is soft,
Alternatively, it is possible to set a combination of the expansion side being soft and the compression side being hard.

In the proportional solenoid 36, since the chambers 45a and 45b at both ends of the movable iron core 46 in the oil chamber 45 are communicated with each other by the through-hole 52, the chambers 45a and 45
The movable core 46 can be moved smoothly by circulating the oil liquid corresponding to the volume change between 45b. In addition, the pressure of the oil liquid acting on both ends of the movable core 46 is balanced, and the movable core 46 is
Driving force can be reduced. On the other hand, the oil chamber 45 due to the intrusion and retreat of the operating rod 49 accompanying the movement of the movable iron core 46
With respect to the volume change of the oil passage 53, the oil path is used to transfer the oil liquid between the circular recess 60 of the fixed iron core 41 and the chamber formed between the diaphragm 57, thereby deforming the diaphragm 57, The change in volume of the chamber 54 can be absorbed by the reservoir 4 on the oil passage side.

The oil passage through which the oil liquid flows by the expansion and contraction of the piston rod 6 by the diaphragm 57 and the oil chamber of the proportional solenoid 36
No foreign matter such as abrasion powder generated on the oil passage side enters the oil chamber 45 because the oil liquid does not flow between the movable iron core 45 and the movable iron core 46 due to the foreign matter adhering to the sliding portion. The occurrence of defects can be prevented.

Before assembling the proportional solenoid 36 to the case 27 (oil passage side) of the damping force generating mechanism 26, the inside of the oil chamber 45 is evacuated and an oil liquid is sealed in advance, so that the inside of the proportional solenoid 36 is reduced. Air can be reliably removed. As described above, by injecting the oil liquid into the proportional solenoid 36 in advance, it is possible to reliably prevent foreign matter from entering the oil chamber 45, and thus it is possible to manage the cleanliness inside the proportional solenoid 36. .

Generally, when a proportional solenoid is used for damping force adjustment, the movable iron core is finely vibrated (dither vibration) in order to make the spool easy to move with respect to the sleeve and to improve the response when the damping force is changed. Like that. According to the present invention, dither vibration of the movable iron core 46 can be reduced by deformation of the diaphragm 57 due to movement of the operating rod 49, and generation of abnormal noise can be reduced.

Since the diaphragm 57 is disposed in the vicinity of the coil 47, the temperature of the diaphragm 57 can be appropriately increased by the heat generated by the coil 47 even when the temperature is low, and the diaphragm 57 made of rubber or the like can be used. Can be sufficiently secured. When the vehicle is started (when the engine is started), a dither current is always supplied to the coil 47 in order to cause the movable iron core 46 to dither vibrate. Before operation of the vessel 1, the diaphragm
The temperature of 57 can be raised moderately.

An oil chamber of the proportional solenoid 36 is formed by the diaphragm 57.
Since the oil passage 45 and the oil passage side are completely isolated from each other, different types of oil liquid in the oil passage side and oil oil in the oil chamber 45 (for example, viscosity, durability, Resistance etc.). Further, in the oil chamber 45 of the proportional solenoid 36, not only the oil liquid but also other fluids (chemical fluids such as brake fluid) can be sealed.

Further, in this embodiment, the oil passage and the oil chamber 45 are provided.
Although the substantially disk-shaped diaphragm 57 made of a flexible material such as rubber is shown as the flexible diaphragm for isolating the fluid chamber from the fluid chamber, the present invention is not limited to this. The O-ring made of a flexible (easily deformable) member such as a sponge may be used to reduce the deformation resistance of the oil passage 45 and the volume of the oil chamber 45. And between the operating rod 49 and the fixed iron core 41.

It should be noted that the present invention is not limited to the damping force adjusting type hydraulic shock absorber of the above-described embodiment, but may be any other type in which the valve element of the damping force adjusting valve is moved by a solenoid. If so, the same can be applied.

[0040]

As described above in detail, according to the damping force-adjusting hydraulic shock absorber of the present invention, the fluid chamber inside the solenoid casing is isolated from the oil passage by the diaphragm.
Since foreign matter generated on the oil passage side (damping force adjusting mechanism or the like) does not enter the fluid chamber of the solenoid, malfunction of the solenoid due to foreign matter adhering to the sliding portion of the movable member can be prevented. Before assembly, the oil liquid is sealed in the fluid chamber of the solenoid in advance, so that entry of foreign matter into the fluid chamber of the solenoid can be reliably prevented. The degree can be managed. In addition, due to the deformation of the diaphragm caused by the movement of the movable member, vibration such as dither vibration of the movable member can be relieved, and generation of abnormal noise can be reduced.

[Brief description of the drawings]

FIG. 1 is an enlarged view showing a proportional solenoid actuator and a damping force adjusting valve of a damping force generating mechanism, which are main parts of the apparatus of FIG. 2;

FIG. 2 is a longitudinal sectional view of a damping force adjusting type hydraulic shock absorber according to one embodiment of the present invention.

FIG. 3 is an enlarged view showing an operation rod and a diaphragm of the proportional solenoid actuator shown in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Damping force adjustable hydraulic shock absorber 2 Cylinder 6 Piston rod (rod) 17,20 Annular oil passage (oil passage) 18,21,28,29,30 Oil passage (oil passage) 23,24 Connection pipe (oil passage) 25 Connection hole (oil passage) 35 Spool valve (damping force adjustment valve) 36 Proportional solenoid (solenoid) 41,42 Fixed iron core (casing) 44 Plug (casing) 45 Oil chamber (fluid chamber) 46 Movable iron core (movable member) 47 Coil 48 Spacer (casing) 50 Spool (valve) 57 Diaphragm

Claims (1)

[Claims] 1. A cylinder filled with an oil liquid, a rod that expands and contracts with respect to the cylinder, an oil passage through which the oil liquid flows by expansion and contraction of the rod, and a flow control oil oil provided in the oil passage. A damping force adjusting valve that adjusts the damping force by adjusting the damping force, and a solenoid that drives a valve element of the damping force adjusting valve. A casing that forms a chamber inside, a coil provided in the casing, and a movable member that is slidably disposed in the fluid chamber and that drives the valve element in accordance with a current supplied to the coil. A damping force-adjustable hydraulic shock absorber, wherein a flexible diaphragm for separating the oil passage and the fluid chamber is provided between the oil passage and the fluid chamber.