JPH0742912Y2 - Annular spacer - Google Patents

Description

TECHNICAL FIELD The present invention relates to an annular spacer used in a rack-and-pinion type steering device of an automobile, and particularly to a rack shaft and a tie rod for defining a stroke amount of the rack shaft. The present invention relates to an annular spacer externally fitted and attached to a small diameter portion of an annular rock plate that is fitted over the socket end portion and the rack shaft end portion of a ball joint that connects with each other.

Prior Art FIG. 5 shows a connecting portion between a rack shaft 4 and a tie rod 9 which is a part of a rack and pinion type steering device. At the connecting portion, the end of the rack shaft 4 that reciprocates in the axial direction is hollow inside the cylinder 1 extending from the gear box, and the hollow rod 5 has a screw rod 8 integral with the socket 7 of the ball joint 6. A ball 10 which is screwed in and integrated with the tie rod 9 is fitted in the socket 7. An annular lock plate 11 is fitted across the end of the socket 7 and the rack shaft end hollow portion 5, and an annular spacer 12 is externally fitted to the small diameter portion of the annular lock plate 11. The annular spacer 12 is, for example, a structure in which an elastic ring 14 made of an elastomer is fixed to the inner circumference of a metal ring 13 as shown in FIG. The elastic ring 14 serves as a mounting portion for mounting the annular spacer 12 on the lock plate 11.
The inner diameter (r) is smaller than the outer diameter of the small diameter portion of the lock plate 11, so that the annular spacer 12 is fitted onto the lock plate 11 with the tooth-like projections 15 of the elastic ring 14 compressed and deformed. . In the figure, (B) shows a bellows-shaped rubber boot mounted on the large diameter portion 2 of the tube 1 and the tie rod 9 so as to be straddled.

In FIG. 5, when the rack shaft 4 is moved sufficiently to the left during wheel steering, the annular spacer 12 enters the large diameter portion 2 of the cylinder 1 and its metal ring 13 strikes the end wall 3 to bring the rack shaft 4 into contact. Cannot move further to the left. That is, the stroke amount of the rack shaft 4 to the left is defined by the contact relationship of the annular spacer 12 with the end wall 3.

Problems to be solved by the invention Since the annular spacer 12 is fixed on the lock plate 11 by utilizing the elastic deformation of the elastic ring 14, it is possible that the annular spacer 12 falls off from the lock plate 11 due to vibration or the like. And the annular spacer 12 once has the rack axis 4.
When released, the elastic ring 14 has an interference with the lock plate 11 so that the annular spacer 12 has an inner diameter r of the elastic ring 14.
Is larger than the outer diameter of the rack shaft 4 and is not centered (centering with respect to the lock plate 11), so that even if it hits the end wall 3 during use, it does not return to the lock plate 11. .

The present invention was devised under such a technical background, and its purpose is to move the rack shaft so that the annular spacer contacts the end portion of the gear box cylinder even if the annular spacer falls off the lock plate. The object is to obtain an annular spacer having a shape that can be easily returned to the lock plate by being contacted and pressed.

Means for Solving the Problem and Its Action The above-mentioned object is that the mounting portion inside the metal ring has a thin elastic projecting piece that projects inside the metal ring inward in the radial direction, The projecting piece is mounted in a state of being pressed and bent in a contact relationship with the outer peripheral surface of the annular rock plate, and the projecting piece is the projecting piece when the annular spacer falls off from the annular rock plate. To provide an annular spacer having a length and rigidity such that the leading edge of the blade contacts the peripheral surface of the rack shaft and centers the annular spacer with respect to the annular lock plate. .

With such an annular spacer, the annular spacer that has fallen off the lock plate and moved on the rack axis can be centered with respect to the lock plate, and the thickness of the protruding piece can be appropriately reduced. By forming it, the bending is facilitated, and the protruding piece can be sandwiched at a position between the metal ring and the outer peripheral surface of the lock plate with a predetermined interference. Therefore, when the rack shaft moves with the annular spacer on the rack shaft and the annular spacer is pressed against the end of the gear box cylinder, the protruding piece is bent from the root by the load and has a predetermined fitting force. The annular spacer is fitted back onto the lock plate.

Example Hereinafter, one example shown in FIGS. 1 and 2 will be described. In the figure, the rack shaft 4, the socket 7 of the ball joint 6, and the annular lock plate 11 have been described above, and therefore their explanations are omitted.

FIG. 1 shows a state in which the annular spacer 20 is placed on the rack shaft 4 and is not yet attached to the small diameter portion of the annular lock plate 11. The annular spacer 20 is composed of a metal ring 21 and an elastic elastic ring 22 fixed to the inner circumference of the metal ring 21. The elastic ring 22 serves as a mounting portion for mounting the annular spacer 20 onto the small diameter portion of the annular lock plate 11. The width of the elastic ring 22 is equal to the width W of the metal ring 21, and a projecting piece 23 located at the center of the width and having a wall thickness t sufficiently smaller than the width W is integrated over the entire inner circumference of the main body of the elastic ring 22. Is formed so as to project. The tip edge of the projecting piece 23 (that is, the inner circumference of the annular spacer 20) is in contact with the peripheral surface of the rack shaft 4, so that the axis (center) of the annular spacer 20 is the rack shaft 4.
And on the axis of the annular lock plate 11. here,
When the length of the protruding piece 23 is 1, the inner diameter of the elastic ring 22 is D ₁ , and the outer diameter of the small diameter portion of the annular lock plate 11 is D ₂ (where D ₁ > D ₂ ), the wall thickness t of the protruding piece 23 is It is necessary to satisfy the expression t> (D ₁ −D ₂ ) / 2. The reason is that an appropriate tightening margin can be obtained in the state where the annular spacer 20 is fitted in the small diameter portion of the annular lock plate 11 as shown in FIG. Further, the wall thickness t must satisfy the above formula, and at the same time, the protruding piece 23 should have a size that does not easily bend on the rack shaft 4 but provides sufficient rigidity for centering.
The protrusion 23 should be large enough to be easily bent from the root when the 20 is pressed against the annular lock plate 11.

When the annular spacer 20 centered on the rack shaft 4 and the annular lock plate 11 and pushed in from the left in the state shown in FIG. 1, the protruding piece 23 comes into contact with the small diameter end of the annular lock plate 11 from the root due to the load. After bending, the annular spacer 20 is attached to the small diameter portion of the annular lock plate 11 as shown in FIG.
Is fitted on the outside. At this time, the protruding piece 23 is compressed by the contact relationship of the annular lock plate 11, and an appropriate tightening margin is obtained. Further, in this state, if the tip edge of the projecting piece 23 projects beyond the end surface of the annular spacer 20 main body, it affects the stroke amount of the rack shaft 4. Therefore, select the length l of the projecting piece 23 so as not to project. There must be.

Thus, from the state shown in FIG. 2 in which the annular spacer 20 is fitted on the annular lock plate 11, even if the annular spacer 20 falls off from the annular lock plate 11 due to vibration or the like,
By the projecting piece 23, the rack shaft 4 and the annular lock plate
Since the annular spacer 20 is centered with respect to 11, and the inner diameter D _{1 of the} main body of the elastic ring 22 is made larger than the outer diameter D ₂ of the small diameter portion of the annular lock plate 11, the rack shaft 4 is located on the cylinder side of the gear box ( When the annular lock plate 11 pushes the annular spacer 20 against the end of the gear box cylinder by moving it to the left side of FIGS. 1 and 2, the protruding piece 23 bends and the annular spacer 20 is re-fitted on the annular lock plate 11. To meet. Therefore, the annular spacer 20 can always perform its function.

Note that the protruding piece 23 does not have to be formed over the entire inner circumference of the elastic ring 22 body, and may be discontinuously divided into a plurality of pieces. Further, in the embodiment of FIGS. 1 and 2, a groove 24 is provided at a position adjacent to the base of the protruding piece 23 in order to enhance the flexibility of the protruding piece 23, but this groove 24 is omitted. Of course it is possible. Further, in addition to the groove 24 or instead of the groove 24, it is possible to provide a groove or a recess for improving the flexibility of the protruding piece 23 at positions near the roots of both side surfaces of the protruding piece 23.

Further, although the protruding piece 23 is provided at the center of the width of the annular spacer 20, the position thereof does not necessarily have to be the center of the width.
However, when the projecting piece 23 is provided in the central portion of the width, the work efficiency is good because it is not necessary to consider the assembling direction when assembling the annular spacer 20.

On the other hand, the width W of the annular spacer 20 depends on the annular lock plate 11
If the length is smaller than the small diameter part of
Is located, the amount of pinching with the annular lock plate 11 is reduced, and in some cases, the protruding piece 23 cannot be pinched. Therefore, the shapes shown in FIGS. 3 and 4 are established.

The width W of the annular spacer 20A in FIGS. 3 and 4 is sufficiently larger than the length of the small diameter portion of the annular lock plate 11, and projecting pieces 23A, 23A are formed at both ends of the elastic ring 22A. Therefore, when the annular spacer 20A is fitted on the small diameter portion of the annular lock plate 11, one of the protruding pieces 23
A is bent in a contact relationship with the annular lock plate 11, and the tip edge of the other protruding piece 23A is in contact with the outer peripheral surface of the rack shaft 4, and the stable attitude of the annular spacer 20 is maintained by this fitting relationship. Be done.

In the embodiment of FIGS. 1 and 2, the annular spacer
The mounting portion for mounting 20 on the annular lock plate 11 is
The protruding piece 23 is composed of the elastic ring 22 integrally formed, and similarly, the mounting portion in the embodiment of FIGS. 3 and 4 is also structured as the elastic ring 22A integrally formed with the protruding piece 23A. . However, it suffices that the mounting portion has the protruding piece as described above, and does not necessarily have to be configured as the elastic ring 22, 22A as described above. For example, it is possible to configure the mounting portion from only the protruding piece and to have the root portion of the protruding piece directly fixed to the inner surface of the metal ring 21.

EFFECTS OF THE INVENTION As is apparent from the above description, in the annular spacer of the present invention, the mounting portion inside the metal ring has the thin-walled elastic projecting piece that projects inside the metal ring inward in the radial direction. Cage,
The protruding piece is adapted to be externally fitted and mounted on the annular rock plate in a bent state. Further, since the protruding piece has the length and the rigidity as described above, the protruding piece is detached from the annular rock plate to be mounted on the rack shaft. The annular spacer that has been moved to the center can be centered with respect to the annular lock plate, and by making the thickness of the protruding piece appropriately thin, it can be bent easily and a predetermined tightening margin can be obtained. Therefore, the protruding piece can be sandwiched between the metal ring and the ring-shaped lock plate, and the ring spacer that has fallen off from the ring-shaped rock plate due to vibration or the like can be reattached by the movement of the rack shaft. This is done automatically, and the function of the annular spacer is always ensured.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part in which an annular spacer according to an embodiment of the present invention is fitted on a rack shaft, and FIG. 2 is a view showing the annular spacer fitted on an annular lock plate at the end of the rack shaft. FIG. 3, FIG. 3 is a view similar to FIG. 1 showing an annular spacer according to another embodiment, and FIG. 4 is a view in which the annular spacer is externally fitted and attached to an annular lock plate at the end of the rack shaft, FIG. 5 is a view showing a connecting portion between a rack shaft and a tie rod, which is a part of a rack and pinion type steering device, and FIG. 6 is a front view of a conventional annular spacer externally fitted and mounted on an annular lock plate at the connecting portion. It is a figure. 4 ... Rack shaft, 6 ... Ball joint, 7 ... Socket,
9 …… Tie rod, 11 …… Annular lock plate, 20 ……
Ring spacer, 21 …… Metal ring, 22 …… Elastic ring, 23 ……
Protruding piece.

Claims (1)

[Scope of utility model registration request] Claim: What is claimed is: 1. To define a stroke amount of a rack shaft used in a rack and pinion type steering device of an automobile, a ball joint connecting a rack shaft and a tie rod is straddled over a socket end and a rack shaft end. An annular spacer externally mounted on a small diameter portion of an annular lock plate fitted by means of a metal ring and a mounting portion inside the metal ring, wherein the mounting portion covers the inside of the metal ring. It has a thin-walled elastic projecting piece that projects inward in the radial direction, and the projecting piece is mounted in a state of being pressed and bent in a contact relationship with the outer peripheral surface of the annular lock plate. The piece has such a length and rigidity that when the annular spacer falls off the annular lock plate, the tip edge of the protruding piece comes into contact with the peripheral surface of the rack shaft to center the annular spacer on the annular lock plate. An annular spacer characterized by having.