JPH08152038A - Variable damping mechanism for car height adjusting suspension device - Google Patents

Abstract

PURPOSE: To provide the variable damping mechanism of a car height adjusting suspension device which is reduced in size containing an actuator for switching a damping force. CONSTITUTION: A feed discharge oil port 6 for adjusting a car height is formed in the hollow part 5 of a piston rod 1 and a thrust bearing 8 is arranged through fitting of an adjust sheet 7 in the upper end part of the hollow part 5. An annular stopper plate is fixed to the adjust rod 2 through a stopper ring 10 fixed to a run-around groove 9, and the stopper plate is supported on the under side of the thrust bearing 8. A select valve coupled to the adjust rod 2 is fitted in a piston and a slide bearing member is held.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable damping mechanism for a vehicle height adjusting suspension device, and more particularly to a variable damping mechanism for a vehicle height adjusting suspension device which can be downsized including an actuator for switching a damping force.

[0002]

2. Description of the Related Art A damping force variable type vehicle height adjusting suspension system is known in which a piston having a variable damping mechanism is supported by a piston rod so as to be able to move forward and backward, and the vehicle height is adjusted by supplying and discharging hydraulic oil in a cylinder. Has been.

FIG. 4 is a sectional view of a conventional damping force type vehicle height adjusting suspension device. An oil supply / exhaust port 52 is formed in a hollow piston rod 51, and a hollow portion 53 of the piston rod 51 is used as a hydraulic oil supply path. Hydraulic oil is taken in and out through the hydraulic oil supply / exhaust port 52, and the piston rod is moved by the pressure in the cylinder. The vehicle height is adjusted by advancing / retreating (leakage from the seal is recovered from the recovery passage 55), and a rotary variable damping mechanism is provided on the inner peripheral portion of the hollow piston 56 supported by the piston rod 51 so as to be advancing / retracting. By providing the eggplant select valve 57 rotatably by the ball bearing 58,
The present applicant has already proposed a vehicle height adjusting suspension device (Japanese Patent Application No. 5-61214) in which the supply and discharge resistance is suppressed by the variable damping mechanism and the friction when the hydraulic pressure rises is reduced.

In this vehicle height adjusting suspension device, an adjusting rod 59 for switching a damping force is passed through the hollow portion 53 of the piston rod 51, and an actuator 60 for rotating the adjusting rod 59 is provided at the upper end of the piston rod 51. The damping force can be switched according to the command.

[0005]

However, the select valve 57 can be rotated by the ball bearing 58 while a hollow portion is secured in the piston 56 of the vehicle height adjusting suspension device as a flow path for vehicle height adjusting hydraulic oil. With this structure, the outer diameter of the piston rod 51 becomes large, which makes it difficult to reduce the size of the suspension device and the rotation resistance of the actuator 60 makes it difficult to reduce the size of the actuator 60.

[0006]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a piston, which is slidable in a cylinder via a piston rod, and a damping of a rotary variable damping mechanism formed in a hollow portion of the piston. In a vehicle height adjusting suspension device, wherein an adjusting rod for switching force characteristics is rotatably supported by penetrating into the hollow portion of the piston rod, and a vehicle height adjusting oil supply / exhaust port is formed on the piston rod. A thrust bearing that supports the adjust rod is provided at the upper end of the hollow portion of the piston rod.

It is preferable to provide a grooved ring-shaped plain bearing member for receiving the lower end of the select valve of the rotary variable damping mechanism in the hollow portion of the piston.

[0008]

[Operation] Since the thrust bearing for supporting the adjust rod is provided at the upper end of the hollow portion of the piston rod, the thrust force of the variable damping mechanism is supported by the thrust bearing having the small diameter, and is variable in the hydraulic oil passage for adjusting the vehicle height. Since the support of the piston part of the damping mechanism can be simplified, it is possible to minimize the hydraulic fluid flow resistance even when the piston part is configured with a small diameter, and the adjust rod has a large thrust when the hydraulic pressure rises. Even if force is applied, the rotation resistance is kept small by the small diameter bearing.

When a ring-shaped sliding bearing member for receiving the lower end of the select valve is provided in the hollow portion of the piston, it supports the downward force acting at the time of extension, and since the contact area is small due to the grooved bearing, the rotation resistance is reduced. The bearing structure of the thrust bearing supporting the adjust rod can be simplified while keeping the flow path resistance of the hydraulic oil for vehicle height adjustment to a minimum.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 is a vertical sectional view of an upper portion of a piston rod according to an embodiment of the present invention, and FIG. 2 is a vertical sectional view of a lower portion of a piston rod according to an embodiment of the present invention.

In FIG. 1, the vehicle height adjusting suspension device penetrates a small diameter adjusting rod 2 in the center of a piston rod 1, and a guide ring 3a is provided at an upper end of the piston rod 1 so as to surround the adjusting rod 2 by a stopper ring 3a. It is fixed and receives the pressure in the cylinder by an O-ring 4 with a backup ring 4a. A connecting portion 2a is formed at the upper end of the adjusting rod 2 for connecting to an actuator (not shown) for switching and driving the damping force characteristic, and a hollow portion 5 of the piston rod 1 is provided with a vehicle height adjusting oil supply / exhaust port 6. .

At the upper end of the hollow portion 5 of the piston rod 1, a small diameter thrust bearing 8 is provided by fitting an adjusting seat 7 which is a bearing housing made of synthetic resin such as nylon. A ring-shaped stopper plate 10 is fixed to the adjusting rod 2 penetrating the thrust bearing 8 via a stopper ring 9a fixed to the circumferential groove 9, and the stopper plate 10 is received below the thrust bearing 8. , Supports the upward force acting on the adjusting rod 2. The thrust bearing 8 may be a sliding bearing in addition to a ball bearing, and a low-cost small bearing can be used. Also,
The rotation resistance is suppressed, and the adjustment rod is prevented from falling down to enable stable rotation.

In FIG. 2, a hollow piston 13 having an extension side damping valve 11 and a compression side damping valve 12 is provided at the lower end of the piston rod 1, and the adjustment rod 2 is connected to the upper side of the piston 13. The select valve 14 forming a rotary variable damping mechanism is rotatably fitted,
The collar 1 is provided with a slide bearing member 15 having a groove for supporting the lower end.
6 and a stopper ring 17 form a hollow portion 18 in the piston 13 that communicates with the hollow portion 5 of the piston rod 1 and the select valve 14.
The slide bearing member 15 is a low-cost synthetic resin small-diameter member, and can secure the hollow portion 18 of the piston 13 and suppress the rotational resistance during extension with a small thrust force.

The select valve 14 has its housing 1
9, a compression-side damping valve 20 and a plurality of orifices 21
By forming the oil holes 22 and 23 that can communicate with each other, a rotary variable damping mechanism that can obtain damping characteristics according to the rotational angle position thereof is configured.

According to the experimental results, when the rolling bearing is provided on the upper part of the piston rod, the rotation torque of 80% when the select valve portion is supported by the sliding bearing can be reduced, and the rolling bearing can be used as the sliding bearing. In that case, a reduction result of 50% was obtained. This reduces the pressure receiving area, and
This is the effect of reducing the distance between the loads (the radius of gyration), and the same result can be obtained from the analysis by the following calculation model.

FIG. 3 is a calculation model diagram of the rotation resistance, and d0 = 0.3 and d1 = d1 = (a1) and (a2) showing the conventional configuration.
When 1.0, d2 = 1.2 (rotation torque in cm) is To =
0.230 Pμ (unit kgfcm), the same figure showing the configuration of the present invention (b1), (b
Similarly, in 2), the turning torque when d0 = 0.3, d1 = 0.3, and d2 = 0.6 is Tn = 0.0660 Pμ, and the ratio of the two is Tn.
/ To = 0.29, that is, if the friction coefficient is the same,
71% of the conventional turning resistance is reduced. Further, it can be seen that the present invention can surely reduce the rotation resistance in comparison with the conventional configuration even in comparison between the two by the rolling bearing.

The operation of the vehicle height adjusting suspension device configured as described above will be described below. Piston rod 1
By rotating the adjust rod 2 that penetrates
The select valve 14 is rotated to switch the damping characteristic. When the hydraulic oil for adjusting the vehicle height is injected, the hydraulic oil is sent from the oil supply / discharge port 6 through the hollow portion 5 of the piston rod 1, the select valve 14 and the hollow portion 18 of the piston 13 into the cylinder. At this time, the select valve 14 and the hollow portion 18 of the piston 13 form a flow path of the hydraulic oil, and the flow path resistance is minimized.

When the suspension device is expanded or contracted, a damping force is generated by the damping mechanism of the piston 13 and the select valve 14, and a relatively small force acts on the select valve 14 downward in the extension stroke. This force is supported by the bearing member 15 held by the collar 16 and the stopper ring 17. The rotation resistance of the bearing member 15 at this time is relatively small, and the select valve 14 can be easily rotated by a small turning force to switch the damping characteristic.

In the compression stroke, a relatively large force acts on the select valve 14 upward due to the large pressure in the cylinder, and this force is supported by the thrust bearing 8 via the stopper plate 10 of the adjusting rod 2. At this time, the rotational resistance of the thrust bearing 8 is kept relatively small due to its small diameter, and the select valve 14 can be easily rotated by a small turning force to switch the damping characteristic. In particular, when the thrust bearing 8 is composed of a ball bearing, the dependency on the internal pressure of the cylinder is reduced, and the turning resistance can be greatly suppressed. In addition, select valve 14
If the diameter is reduced, the rotation resistance can be further suppressed by the effect of reducing the pressure receiving area and the effect of reducing the distance between the loads.

As described above, the variable damping mechanism of the vehicle height adjusting suspension device according to the present invention minimizes the flow path resistance of the hydraulic oil for vehicle height adjusting, and at the same time, reduces the size of the actuator and the piston portion of the suspension. It is possible to reduce the size and weight of the entire device and reduce the cost.

[0021]

According to the present invention as described above,
Since the thrust bearing that supports the adjust rod is installed above the oil supply / drain port of the piston rod, the thrust force acting on the variable damping mechanism is supported by the small diameter thrust bearing, and the thrust bearing is the oil of hydraulic oil for vehicle height adjustment. It does not affect the road, and the lower part of the sliding portion of the variable damping mechanism interposed in the oil passage for the vehicle height adjusting hydraulic oil can be simplified and the diameter can be reduced. Further, even if a large thrust force acts on the adjusting rod, the rotation resistance of the bearing is suppressed to a small value by the bearing.

Therefore, the vehicle height adjusting suspension device is provided with a variable damping mechanism while minimizing the flow resistance of the hydraulic oil for vehicle height adjusting, and the actuator and the piston portion are miniaturized to provide the entire suspension device. It is possible to reduce the size and weight and reduce the cost.

When the lower end of the variable damping mechanism is supported by the ring-shaped bearing member, it supports the downward force acting at the time of extension, and the grooved bearing has a small contact area, so that the turning resistance is suppressed and the vehicle height is reduced. It is possible to simplify the bearing structure of the adjust rod while suppressing the increase in the flow resistance of the hydraulic fluid for adjustment to the minimum.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an upper portion of a piston rod according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view of a lower portion of a piston rod according to an embodiment of the present invention.

[Fig. 3] Calculation model diagram of rotation resistance

FIG. 4 is a sectional view of a conventional damping force variable vehicle height adjustment suspension device.

[Explanation of symbols]

1 ... Piston rod, 2 ... Adjust rod, 3 ... Guide bush, 4O ... Ring, 5 ... Hollow part, 6 ... Oil supply / drain port, 7 ... Adjust seat, 8 ... Thrust bearing,
9 ... Circular groove, 9a ... Stopper ring, 10 ... Stopper plate, 11 ... Extension side damping valve, 12 ... Compression side damping valve, 13 ... Piston, 14 ... Select valve (rotary variable damping mechanism), 15 ... Sliding bearing member , 16 ... Color, 1
7 ... Stopper ring, 18 ... Hollow part, 19 ... Housing, 20 ... Compression side damping valve, 21 ... Orifice, 22, 2
3 ... Oil hole.

Claims (2)

[Claims] 1. A piston is provided slidably in a cylinder via a piston rod, and an adjusting rod for switching damping force characteristics of a rotary variable damping mechanism configured in the hollow portion of the piston is provided in the hollow portion of the piston rod. It is pierced and rotatably supported, and a vehicle height adjustment oil supply / drain port is formed in the piston rod, and the vehicle height is adjusted by supplying / discharging hydraulic oil to / from the cylinder through the hollow part of the piston. A variable damping mechanism for a vehicle height adjusting suspension device, wherein a thrust bearing for supporting the adjusting rod is provided above an oil supply / exhaust port that opens in a hollow portion of the piston rod. 2. The variable damping mechanism for a vehicle height adjusting suspension device according to claim 1, wherein a hollow ring portion of the piston is provided with a grooved ring-shaped bearing member for receiving a lower end of a select valve of the rotary variable damping mechanism. A variable damping mechanism for a vehicle height adjusting suspension device.