JPH0226772Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a rack and pinion type steering device, in particular to an improvement of a rack support structure for slidably supporting a rack within a steering body.

[Conventional technology]

In terms of steering devices, rack and pinion type steering devices have the advantage of being relatively simple in structure, compact and lightweight, and not only are advantageous in terms of installation space, but also have excellent steering performance. In recent years, they have come to be widely installed in various vehicles, including small cars.

To briefly explain this using the rack and pinion type steering device 1 for manual steering shown in FIG. Rack teeth of a rack 5 constituting a steering link mechanism 4 which is fitted into a steering body indicated by the reference numeral 3 and has a pinion provided at its tip that is suspended horizontally between steering wheels (both not shown) of the vehicle. It is meshed with 5a. In the figure, reference numeral 6 indicates a king pin provided at both ends of the steering link mechanism 4 and connected to the pitman arm on the steering wheel side;
is a tie rod connected to this, and the rack 5 is provided in series between the tie rods 7, 7 on both the left and right sides, with the rack 5 interposed via a ball joint 7a. Further, 3a is a cylindrical housing integrally formed with the steering body 3 so as to surround the steering link mechanism 4, and is equipped with a pair of mounting brackets 8, 8, etc. to be assembled on the vehicle side. Bellows-like elastic cylinders (boots) 9, 9 are disposed between the tie rod 7 on both ends thereof, and are configured to ensure sealing performance from these parts.

By the way, in the steering device 1 having the above-described structure, the rack 5 that is connected in series with the tie rod 7 to constitute the steering link mechanism 4 is a rack guide ( (not shown), and the rod portion 5b on the other end side is slidably supported by a rack support bushing 10 loaded into the end of the cylindrical housing 3a integrated with the steering body 3. It was designed to be supported in a freely movable manner.

[Problem that the invention attempts to solve]

However, in the conventional rack support bushing 10 as described above, a cylindrical shape made of, for example, oil-impregnated sintered metal material is simply inserted into the inner hole of the housing 3a on the body 3 side from its outer end. Because it is simply press-fitted and retained, and the outer end is locked with a retainer ring, etc.
This bush 10 has no degree of freedom, and strict machining accuracy is required for the body housing 3a and the like in order to ensure device performance, resulting in problems in terms of machinability. That is, the rack 5 in this type of steering device 1 is subjected to considerable rocking displacement in relation to the tie rod 7 side, and when such a rack 5 is held by the bush 10, which is a rigid body having a cylindrical shape, Depending on the rocking displacement of the rack 5, the rack 5 may come into contact with the bush 10 in a point contact state, and as a result, it is likely to come into uneven contact with the inner diameter part of the bush 10, which may reduce the durability of these sliding parts. This caused problems. and,
According to the relationship between the rack 5 and the bush 10, it is impossible to avoid the generation of noise due to unnecessary collisions, and the degree of freedom of the rack 5 is hindered, which causes problems in maintaining its proper operating performance. Therefore, it is desirable that some kind of countermeasure be taken.

[Means for solving problems]

In order to meet such demands, the rack support structure of the steering device according to the present invention includes a rack support bush that is loaded into the steering body from one end and held therein, and is made of oil-impregnated sintered metal material into a cylindrical shape. At the same time, an elastic coating layer is formed on the outer periphery of the body, and the body is locked and held so as to be able to swing in the longitudinal direction by a protrusion that is inwardly ejected from the outside of the body and corresponds to the approximately central portion in the longitudinal direction. This is how it was done.

[Effect]

According to the present invention, a rack supporting bush made of oil-impregnated sintered metal material having a cylindrical shape and having an elastic coating layer formed on the outer periphery is inserted into an inner hole on the steering body side at approximately the center in the longitudinal direction of the bush. It is possible to support the rack in a swingable state along the longitudinal direction by a protrusion that is inwardly pushed out at a portion corresponding to the rack, so that the rack can be supported by the protrusion along with the rack regardless of its swinging displacement. The bushing can be held stably and appropriately by a bush that swings using the part as a fulcrum, and can maintain its proper sliding motion.

〔Example〕

Hereinafter, the present invention will be explained in detail using embodiments shown in the drawings.

Fig. 1 shows an embodiment of the rack support structure in the steering device according to the present invention, and in these figures, the same or corresponding parts as in Fig. 4 described above are given the same numbers and the explanation thereof will be omitted. .

Now, according to the present invention, the steering body 3
A rack support bushing 20 that is loaded and held from one end into the side cylindrical housing 3a and slidably supports the rod portion 5b of the rack 5 is formed into a cylindrical shape from an oil-impregnated sintered metal material or the like. An elastic coating layer 23 made of rubber or the like is formed on the outer periphery of the body housing 3a, and when loaded into the inner hole 21 of the body housing 3a, it is punched inward from the outside of the body housing 3a corresponding to the approximately central portion in the longitudinal direction. The feature is that the bush 20 is locked and held in a swingable state in the longitudinal direction by a protrusion 22.

That is, according to the present invention, in order to fix the bush 20 loaded in the body housing 3a to the body housing 3a side, the bush 20 is fixed at a plurality of locations around the entire circumference or at predetermined intervals in the circumferential direction approximately at the longitudinal center of the body housing 3a. It is configured so as to utilize a protrusion 22 that is inwardly punched out, and this protrusion 20
Since an elastic coating layer 23 made of rubber or the like is formed in advance on the outer periphery of the bushing 20, the bushing 20 can be easily and properly loaded and fixed, and the bushing 20 can be mounted using the above-mentioned protrusion 22 as a fulcrum.
It is possible to support the rack so that it can swing along the longitudinal direction, thereby increasing its degree of freedom.
can be held in a line contact state, and its stable sliding movement can be appropriately guaranteed.

Furthermore, with this configuration, there is no need to use a retainer ring or the like for fixing the bush 20 as in the conventional case, and there is no need to form a locking groove or the like on the body housing 3a side. The body housing 3a can be formed from a thin pipe body, which is highly effective in terms of workability and cost reduction. Further, according to the above-mentioned configuration, it is possible to reduce the machining accuracy of the body housing 3a, the bush 20, the rack 5, etc., which is a great advantage in terms of the molding process.

Here, it goes without saying that the amount of protrusion of the protrusion 22 from the body housing 3a described above is set to such an extent that it does not affect the inner peripheral surface of the bush 20.

Note that the present invention is not limited to the structure of the embodiment described above, and the shape, structure, etc. of each part may be modified and changed as necessary. For example, as shown in FIGS. 2a and 2b, a plurality of rows of elastic bodies 24 made of resin or the like that protrude at predetermined intervals in the circumferential direction are arranged in parallel on the inner peripheral surface of the rack support bushing 20 described above. If the rack 5 is buried, or if a bar-shaped elastic body 25 extending in the longitudinal direction is buried as shown in FIGS. 3a and 3b,
It becomes possible to appropriately and reliably absorb the rocking displacement applied to the structure and elastically hold it. That is, according to such a configuration, the light load applied to the rack 5 is absorbed by the elastic body 24 embedded in the inner peripheral surface of the bush 20.
Due to multi-sided contact with 25, large loads can be handled by 20 bushes.
By supporting the rack with its own sintered material, it is possible to increase the degree of freedom in supporting the rack 5, reduce the dimensional accuracy of each part, and also prevent noise caused by metal collisions. becomes.

Further, in the above embodiment, the case where the rack support structure according to the present invention is applied to a steering device for manual steering is explained, but the present invention is not limited to this, and can also be applied to a steering device for power steering. It is easy to see what can be done.

[Effects of the invention] As explained above, according to the rack support structure of the steering device according to the present invention, the rack support bushing, which is loaded and held from one end into the steering body, is made of oil-impregnated sintered metal material. The bush is formed into a cylindrical shape, and an elastic coating layer is formed on the outer periphery of the bush, and a protrusion that is inwardly punched out from the outside of the body corresponds to the substantially central part of the bush in the longitudinal direction. Since it is designed to be locked and held in a swingable state, despite its simple and inexpensive structure, the swinging action of the bush itself allows the rack to be held properly and reliably regardless of its swinging displacement. It is possible to fit and hold the sliding part and ensure stable sliding movement.This eliminates problems such as uneven contact of the rack, and improves the durability of this sliding part by using sintered material. It has various practical effects such as being able to significantly improve the processing accuracy of the steering body, and also reducing the machining accuracy on the steering body side and improving its machinability.

[Brief explanation of the drawing]

FIG. 1 is an enlarged cross-sectional view of the essential parts showing one embodiment of the rack support structure in the steering device according to the present invention, and FIGS. 2a, b and 3 a, b show modified examples of the rack support bushing. A schematic perspective view, a sectional view of a main part thereof, and FIG. 4 are schematic diagrams showing a schematic structure of a rack and pinion type steering device for manual steering to which the present invention is applied. 1... Rack and pinion type steering device, 3... Steering body, 3a... Tubular housing, 4
... Steering link mechanism, 5 ... Rack, 5a ... Rack teeth, 5b ... Rod portion, 20 ... Rack support bushing, 21 ... Body side inner hole, 22 ... Inward protrusion, 23 ... ...Elastic body.

Claims (1)

[Scope of utility model registration request] A rack support bushing is installed in the steering body from one end and is held to slidably support the rack. It is characterized by having an elastic coating layer and being held in place so as to be able to swing in the longitudinal direction by a protrusion that is inwardly ejected from the outside of the body and corresponds to the substantially central portion in the longitudinal direction. Rack support structure in steering gear.