JPH0228484B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a coupling device for coupling a piston rod of a shock absorber to a vehicle body.

``Prior Art'' Conventionally, the piston rod of a shock absorber and the vehicle body are connected via an elastic body such as rubber for alignment and vibration absorption.

``Problem to be Solved by the Invention'' However, when the piston rod is greatly displaced and the amount of deformation of the elastic body increases, the reaction force on the piston rod increases rapidly.
For example, when the piston rod is largely displaced relative to the vehicle body, such as when driving on a rough road, the large reaction force applied to the piston rod causes uneven contact between the piston rod and the rod guide, the piston and the cylinder, etc., and this causes the shock absorber to This causes malfunction, resulting in poor ride feeling and reduced durability.

``Means for Solving the Problems'' In view of the above, the present invention has been developed by forming the tip of the piston rod of the shock absorber into a smaller diameter one after another, and having a pair of piston rods spaced apart from each other by a predetermined dimension in the axial direction at the tip. A stepped portion is formed, the tip portion is passed through the inner ring of the spherical bearing, one step portion is brought into contact with one end of the inner ring via a thrust washer, and a nut is screwed onto the tip portion to tighten the nut. While tightening the nut to the other stepped portion, a thrust washer is interposed between the nut and the other end of the inner ring, and the axial dimension between the pair of stepped portions is the same as that of the inner ring and the thrust washer arranged between the stepped portions. The piston rod is rotatably connected to the inner ring of a spherical bearing, and the outer ring of the spherical bearing is attached to the vehicle body via an elastic body.

"Operation" According to the above configuration, when the piston rod swings, the inner ring can swing relative to the outer ring of the spherical bearing. Furthermore, when the piston rod rotates, the contact area between the inner ring and the piston rod is much smaller than the contact area between the outer ring and the inner ring of the spherical bearing, so the piston rod must rotate smoothly relative to the inner ring. Can be done. As a result, it is possible to prevent the elastic body from being significantly deformed due to the rocking and rotation of the piston rod, thereby preventing an increase in the reaction force from the elastic body to the piston rod, thereby preventing the piston rod, rod guide, and piston from increasing due to the reaction force. It is possible to prevent uneven contact in the cylinder or the like. As a result, it is possible to prevent the shock absorber from malfunctioning and to prevent the riding feeling from deteriorating.

In addition, since the swing of the piston rod can be received by the sliding movement between the outer ring and the inner ring of the spherical bearing, and the rotation of the piston rod can be received by the sliding movement of the piston rod and the inner ring, The sliding part can be made into a separate part, thereby improving the durability of the spherical bearing.

"Example" The present invention will be described below with reference to the illustrated example.
In the figure, reference numeral 11 denotes a piston rod of a shock absorber used in a front suspension.The upper tip of the piston rod is formed in successively smaller diameters, and the tip has a pair of stepped portions 11a and 11b spaced apart by a predetermined dimension in the axial direction. is formed.

A bushing 18 is provided on the shaft of the inner ring 12a constituting the spherical bearing 12.
The tip of the piston rod 11 is rotatably passed through the bush 18, and a lower step 11b formed on the piston rod 11 is brought into contact with the lower end of the inner ring 12a via a thrust washer 20.

Then, a nut 13 is screwed onto the tip of the piston rod 11 passed through the inner ring 12a, and the nut 13 is tightened to the upper stepped portion 11a via the washer 14. A thrust washer 19 is interposed between the inner ring 12a and the inner ring 12a.

At this time, the axial dimension of the pair of step portions 11a, 11b is determined by the inner ring 12a and the two thrust washers 1 disposed between the step portions 11a, 11b.
The nut 1 is set to be slightly larger than the total dimension in the axial direction of the nuts 1 and 20.
3 is strongly tightened, the two thrust washers 19 and 20 do not pinch the inner ring 12a, thereby rotatably connecting the piston rod 11 to the inner ring 12a of the spherical bearing 12. .

Furthermore, the outer ring 12b of the spherical bearing 12 includes:
A cylindrical collar 15 is attached to the outer periphery of the cylindrical collar 15, and between the outer periphery of the cylindrical collar 15 and the inner periphery of the cylindrical support portion 16a of the vehicle body 16, an elastic body 17 such as rubber is provided.
Vulcanization is provided by press-fitting.

In the above configuration, the pair of stepped portions 11a and 11b formed on the piston rod 11 are provided at such intervals that the inner ring 12a is not fixed to the piston rod 11, so even if the nut 13 is strongly tightened, the piston rod 11 cannot be fixed. It can be rotatably connected to the inner ring 12a.

Generally, the clearance between the inner ring 12a and the outer ring 12b of the spherical bearing 12 is tighter than the clearance between the inner ring 12a and the piston rod 11, which is the fitting of a normal shaft. A contact area between the outer ring 12b and
Even if the contact area between the inner ring 12a and the piston rod 11 is the same, the piston rod 1
1 is rotated, the inner ring 12a and the outer ring 12b
The piston rod 11 rotates relative to the piston rod 11.
It is more likely that the inner ring 12a and the inner ring 12a rotate relative to each other.

In addition, the contact area between the inner ring 12a and the outer ring 12b is smaller than that between the inner ring 12a and the piston rod 1.
1. Therefore, when the piston rod 11 is rotated, there is a greater possibility that the piston rod 11 will rotate relative to the inner ring 12a than that the inner ring 12a will rotate relative to the outer ring 12b. will be much higher.

As a result, when the piston rod 11 swings from side to side, the inner ring 12a of the spherical bearing 12 swings relative to the outer ring 12b, and the piston rod 11
When the piston rod 11 rotates, the piston rod 11 is
Since the elastic body 17 can be rotated relative to 2a, the elastic body 17 is hardly deformed by the swinging or rotation.

Therefore, the vibrations of the piston rod 11 can always be well absorbed by the elastic body 17, and since the elastic body 17 does not apply a large reaction force to the piston rod 11 unlike in the past, the piston rod 11 and a rod guide (not shown) This prevents uneven contact between the cylinders and the like, ensuring smooth operation of the shock absorber and contributing to improved durability.

In addition, the rocking of the piston rod 11 is controlled by the inner ring 12a.
and the outer ring 12b, the piston rod 1
Since the rotation of piston rod 1 can be received by sliding between this and inner ring 12a, piston rod 1
1 is fixed to the inner ring 12a and the rotation of the piston rod 11 is also received by sliding between the inner ring 12a and the outer ring 12b, making it possible to improve the durability of the spherical bearing 12.

Note that the washer 14 may be omitted. Furthermore, at least the inner surface of the bush 18, the upper surface of the upper thrust washer 19, and the lower surface of the lower thrust washer 20 may be coated with a low-friction synthetic resin or solid lubricant, or subjected to surface treatment such as nitrogen treatment. good. Alternatively, the bushing 18 and the thrust washers 19 and 20 are made of a bimetallic material made of a material with excellent low friction and a material as a backing metal, and the bimetallic material is arranged with the low-friction material side facing the above-mentioned surface treatment side. You may.

Further, the bush 18 and either one of the thrust washers 19 or 20 may be integrally formed into a flanged bush, and the spherical bearing 12 may be of an oil-impregnated type.

``Effects of the Invention'' As described above, according to the present invention, the rocking of the piston rod is caused by the sliding between the outer ring and the inner ring of the spherical bearing, and the rotation of the piston rod is caused by the sliding between the piston rod and the inner ring. Therefore, the durability of the spherical bearing can be improved. In addition, since the elastic body is not significantly deformed by the rocking and rotation of the piston rod, the reaction force from the elastic body to the piston rod is prevented from increasing, and the reaction force can be applied to the piston rod and the rod guide, the piston and the cylinder, etc. It is possible to prevent uneven contact and the like, thereby preventing malfunction of the shock absorber and deterioration of riding feeling.

[Brief explanation of drawings]

The figure is a longitudinal sectional view showing an embodiment of the present invention. 11... Piston rod, 11a, 11b...
Stepped portion, 12... Spherical bearing, 12a... Inner ring, 12
b... Outer ring, 13... Nut, 16... Vehicle body, 1
7...Elastic body, 19,20...Thrust washer.

Claims (1)

[Claims] 1. The tip of the piston rod of the shock absorber is formed to have a smaller diameter in sequence, a pair of stepped portions are formed at a predetermined distance in the axial direction at the tip, and the tip is passed through the inner ring of the spherical bearing. One step is brought into contact with one end of the inner ring via a thrust washer, and a nut is screwed onto the tip of the nut to tighten the nut to the other step, and the nut and the other end of the inner ring are connected. A thrust washer is interposed between them, and the axial dimension between the pair of stepped portions is set to be slightly larger than the total dimension in the same direction of the inner ring and the thrust washer arranged between the stepped portions, so that the piston rod has a spherical surface. A coupling device for a shock absorber, characterized in that it is rotatably coupled to an inner ring of a bearing, and the outer ring of the spherical bearing is further attached to a vehicle body via an elastic body.