JPH0742913Y2 - 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 define a stroke amount of a rack shaft, a rack shaft and a tie rod. 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. 7 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 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 (d) 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 in a state in which the tooth-like protrusions 15 of the elastic ring 14 are 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. 7, when the rack shaft 4 moves sufficiently to the left during steering of the wheels, the annular spacer 12 enters the large diameter portion 2 of the cylinder 1 and its metal ring 13 strikes the end wall 3 and the rack shaft 4 Cannot move further to the left. That is, the stroke amount of the rack shaft 4 to the left is defined by the contact 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 the elastic ring 14 is disengaged upward, the annular spacer 12 whose elastic ring 14 has a tightening margin with respect to the lock plate 11 has a larger inner diameter (d) than the outer diameter of the rack shaft 4 and is centered (with respect to the lock plate 11). (Centering) is not done, and even if it hits the end wall 3 during use,
It never returns to the lock plate 11.

The present invention was devised under such a technical background, and its purpose is to move the rack shaft and cause the annular spacer to contact the end of the gear box cylinder even if the annular spacer falls off the lock plate. An annular spacer that is designed to easily return to the lock plate by being pressed against it, and that does not easily come off from the lock plate without impairing the ease of mounting or returning to the lock plate. Is to get.

Means for Solving the Problem and Its Action In order to achieve the above-mentioned object, the annular spacer of the present invention has a thin-walled elastic member in which the mounting portion inside the metal ring projects inside the metal ring inward in the radial direction. Between the annular spacer portion facing the outer peripheral surface through the bent protruding piece, the protruding piece is externally fitted and mounted on the outer peripheral surface of the annular lock plate in a bent state. It is configured to be sandwiched in the compressed state. The projecting piece has such a length and rigidity that when the annular spacer falls off the annular lock plate, the tip edge of the projecting piece contacts the peripheral surface of the rack shaft to center the annular spacer with respect to the annular lock plate. ing. Further, a configuration in which the wall thickness near the tip of the protruding piece is made larger than the wall thickness near the root thereof, and the inner diameter of the portion of the annular spacer portion located near the tip of the bent protruding piece is defined as the annular spacer portion. Of the bent projecting piece, the inner diameter of which is smaller than the inner diameter of the portion located near the base of the bent protruding piece.

In such an annular spacer, the annular spacer that has fallen off the lock plate and moved on the rack shaft 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 annular spacer portion 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.

Further, a configuration in which the wall thickness near the tip of the protruding piece is made larger than the wall thickness near the root thereof, and the inner diameter of the portion of the annular spacer portion located near the tip of the bent protruding piece is defined as the annular spacer portion. At least one of the inner diameter of the bent protruding piece and the inner diameter of the portion located near the root of the protruding piece is adopted, so that the annular spacer is fitted on the outer peripheral surface of the annular lock plate. In the bent state, the vicinity of the tip of the bent protruding piece is compressed more strongly than the vicinity of the root thereof. Therefore, the fitting stress distribution is always high near the tip of the protruding piece and small at the root side.
Therefore, the internal stress acts from the vicinity of the tip toward the root side, and even if a force for dropping the annular spacer from the annular lock plate is applied, the annular spacer is unlikely to drop from its stress distribution. And these configurations are
Since it does not hinder the bendability of the projecting piece from the vicinity of the root, the structure does not impair the mountability or the recoverability of the annular spacer to the annular lock plate.

Example One example shown in FIGS. 1 and 2 will be described below. In the figure, the rack shaft 4, 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 is integrally formed at the center of the width of the elastic ring 22 over the entire inner circumference of the main body of the elastic ring 22. The protruding piece 23 has a thickness that is sufficiently smaller than the width W as a whole, and the wall thickness near the tip of the protruding piece 23 is larger than the wall thickness near the root. The tip edge of the protruding piece 23 (that is, the inner circumference of the annular spacer 20) is in contact with the peripheral surface of the rack shaft 4, and therefore the axis (center) of the annular spacer 20 is the axis of the rack shaft 4 and the annular lock plate 11. On the line. 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 protruding piece is
As for the wall thickness of 23, at least the wall thickness t near the tip is expressed by the formula t>
It is necessary to satisfy (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 of the entire projecting piece 23 must be such that the projecting piece 23 does not easily bend on the rack shaft 4 but provides sufficient rigidity for centering, and the annular spacer 20 has an annular lock. The protruding piece 23 should be so large that it can be easily bent from its root when pressed against the 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 sandwiched in a compressed state between the outer peripheral surface of the annular lock plate 11 and the portion 20 ′ of the annular spacer 20 facing the outer peripheral surface via the protruding piece 23, and an appropriate tightening margin is provided. Is obtained. Further, in the state shown in FIG. 2, the tip edge of the protruding piece 23 is the annular spacer 20.
Since there is a possibility that the stroke amount of the rack shaft 4 may be affected if it projects beyond the end surface of the main body, it is preferable to select the length l of the projecting piece 23 so as not to project. However, when the stroke amount is not affected, for example, when the rack shaft 4 moves leftward from the state of FIG. 7 and the annular spacer hits the end wall 3, the tip edge of the protruding piece 23 contacts the end wall 3. In the case of entering the hole 3'without abutting, the tip edge of the projecting piece 23 may project from the end surface of the annular spacer body.

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.

Further, as described above, since the wall thickness in the vicinity of the tip of the protruding piece 23 is larger than the wall thickness in the vicinity of the root, the annular spacer 20 is less likely to fall off the annular lock plate 11. That is, as shown in FIG. 2, when the annular spacer 20 is externally fitted and attached to the outer peripheral surface of the annular lock plate 11, the vicinity of the tip of the bent protruding piece 23 is compressed more than the vicinity of the root. . Therefore, the fitting stress distribution is always
The area near the tip is high and the area near the base is small. Therefore, the internal stress acts from the vicinity of the tip toward the root side as shown by the arrow B, and even if a force (see the arrow A in FIG. 2) for removing the annular spacer 20 from the annular lock plate 11 is applied, The annular spacer is hard to come off.

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 the thickness near the tip of the elastic ring 22A is close to the root. Larger protruding pieces 23A, 23A are formed. This annular spacer 20A is an annular lock plate 1
In the state of FIG. 4 fitted on the small-diameter portion of 1, one protruding piece 23A is a portion of the annular lock plate 11 that faces the outer peripheral surface of the annular spacer 20A and the annular spacer 20A via the protruding piece 23A. It is sandwiched between 20A 'and compressed. Further, the tip end edge of the other protruding piece 23A is in contact with the outer peripheral surface of the rack shaft 4, and the stable posture of the annular spacer 20A is maintained.

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.

The annular spacers 20B and 20C shown in FIGS. 5 and 6 are
These are modifications of the annular spacers 20 and 20A, and the protruding pieces 23B and 23C of the annular spacers 20B and 20C have a substantially uniform thickness from the tip to the root. The inner peripheral surface of the elastic ring 22B is provided with an inclined surface 25B that is inclined so as to gradually reduce the diameter from the vicinity of the center toward both the left and right sides, while the inner peripheral surface of the elastic ring 22C, An inclined surface 25C is provided so as to gradually increase from the center toward the left and right sides. Therefore, annular spacers 20B, 2
When 0C is mounted on the outer peripheral surface of the annular lock plate 11, the inner diameter of the annular spacer portion located near the tips of the projecting pieces 23B, 23C and contacting with the annular piece is located near the roots of the projecting pieces 23B, 23C. It is smaller than the inner diameter of the spacer part. By providing the inclined surfaces 25B and 25C as described above, when the annular spacers 20B and 20C are mounted on the annular lock plate 11, the vicinity of the tips of the protruding pieces 23B and 23C is compressed more strongly than the vicinity of the root thereof. Therefore, it is possible to prevent the annular spacer from falling off as in the case of the embodiments of FIGS. 1, 2 and 3 and 4.

In addition, as shown in FIGS. 1, 2 and 3 and 4, the wall thickness near the tip of the protruding piece is made larger than that near the root, and inclined surfaces 25B and 25C as shown in FIGS. 5 and 6 are provided. By adopting a combination with the configuration, it is possible to make the vicinity of the tip of the protruding piece compressed more than the vicinity of the root when the annular spacer is mounted on the annular lock plate.

Effect of the Invention As is apparent from the above description, in the annular spacer of the present invention, the annular spacer that has fallen from the annular lock plate and moved on the rack shaft can be centered with respect to the annular lock plate. Also, by properly forming the wall thickness of the projecting piece, the projecting piece can be bent easily, and the projecting piece has a predetermined tightening allowance to form the outer circumferential surface of the annular lock plate and the bent projecting piece. It can be put in a state of being sandwiched between the annular spacer portion facing the outer peripheral surface and the annular spacer which is dropped from the annular rock plate due to vibration or the like by re-installation by the movement of the rack shaft. This is done automatically, and the function of the annular spacer is always ensured.

In addition, since the annular spacer of the present invention is compressed more strongly than the vicinity of the root of the protruding piece when the annular spacer is mounted on the outer peripheral surface of the annular lock plate, It has the effect of being hard to drop off.

[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 an annular spacer of FIG. 3 externally fitted to an annular lock plate at the end of the rack shaft. FIG. 5 is a view similar to FIG. 1 showing an annular spacer according to still another embodiment, and FIG. 6 is a view similar to FIG. 3 showing an annular spacer according to yet another embodiment, and FIG. FIG. 8 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. 8 is a front view of a conventional annular spacer externally mounted on an annular lock plate at the connecting portion. Is. 4 ... Rack shaft, 6 ... Ball joint, 7 ... Socket,
9 …… Tie rod, 11 …… annular lock plate, 20,20
A, 20B, 20C …… annular spacer, 21 …… metal ring, 22A, 22
B, 22C ... elastic ring, 23,23A, 23B, 23C ... protruding piece.

Claims (3)

[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 fitted to 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 elastic projecting piece that projects inward in the radial direction, the thickness near the tip of this projecting piece is larger than the thickness near the root of the projecting piece, and the projecting piece is bent in an annular lock. The plate is externally fitted and mounted on the outer peripheral surface of the plate, and is sandwiched in a compressed state between the plate and the annular spacer portion facing the outer peripheral surface via the bent protruding piece. , The annular spacer is annular An annular spacer having a length and rigidity such that the tip end edge of the protruding piece comes into contact with the peripheral surface of the rack shaft to center the annular spacer with respect to the annular lock plate when the annular spacer falls off the lock plate. . 2. A rack and pinion type steering device for an automobile, wherein a stroke of a rack shaft is regulated so that the rack shaft and the tie rod are connected to each other by straddling a socket end and a rack shaft end of a ball joint. An annular spacer externally fitted to 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 protruding piece that protrudes inward in the radial direction, and is externally fitted and mounted on the outer peripheral surface of the annular lock plate in a bent state of the protruding piece, and the outer periphery is provided through the bent protruding piece. It is configured to be sandwiched in a compressed state between the annular spacer portion facing the surface,
The inner diameter of the portion of the annular spacer portion located near the tip of the bent protruding piece is smaller than the inner diameter of the portion of the annular spacer portion located near the root of the bent protruding piece, Further, the protruding piece has such a length and rigidity that the tip end edge of the protruding piece comes into contact with the peripheral surface of the rack shaft to center the annular spacer with respect to the annular lock plate when the annular spacer falls off from the annular lock plate. An annular spacer characterized by having. 3. The annular spacer according to claim 2, wherein the wall thickness near the tip of the protruding piece is larger than the wall thickness near the root thereof.