JPS623020B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rack shaft support device for a rack and pinion type steering device for automobiles, which is provided with a pusher that supports a rack shaft behind the rack shaft and elastically presses the pinion toward the pinion. Related.

This kind of rack shaft support device supports a rack shaft supported in a housing so as to be floating or flexible from behind at or near a point where it meshes with a pinion, and elastically presses it toward the pinion. This provides good meshing between the rack and pinion over the entire meshing range, and is often used in rack and pinion type steering devices for automobiles.

Conventionally, as shown in FIG. 11, this type of rack shaft support device has been constructed by inserting a plunger c into a cylinder hole b of a housing a, engaging the plunger c with the back surface of a rack shaft d, and connecting the plunger c with an adjusting screw e. It is known that a spring f is provided between the pinion and the plunger c to spring the plunger c, thereby supporting the rack shaft d and elastically pressing it in the direction of the pinion. In this, the plunger c slides within the cylinder hole b in order to maintain good engagement between the rack and the pinion,
The amount of return is allowed and at the same time limited by the gap t between the plunger c and the adjusting screw e. In such a device in which the plunger c slides inside the cylinder hole b, the plunger c and the cylinder hole b must be precisely fitted in order to ensure smooth sliding of the plunger, and the surface roughness must be smooth. In addition, in order to obtain good engagement with the rack shaft d, the concave surface g of the plunger c that engages with the rear surface of the rack shaft must be made with high dimensional accuracy or a special shape such as a double arc. Precision machining of plunger and cylinder holes results in increased product cost.
Furthermore, when an impactful lateral force is applied to the rack shaft, collisions occur between the plunger and the rack shaft, and between the plunger and the cylinder hole, which tends to generate unpleasant hitting sounds. . Further, in this type of structure, since it is necessary to form a spring chamber behind the plunger, the housing has a partially protruding shape, which may cause problems in mounting to a vehicle.

In order to eliminate this partial protrusion of the housing, a leaf spring consisting of a guide surface that follows the shape of the back of the rack and an end tongue piece is installed in the cylindrical opening formed in the casing on the back of the rack on the opposite side from the pinion. A rack and pinion device was developed in 1987-100744, in which the end tongue of this leaf spring is pressed by a plug inserted into a cylindrical opening to bias the rack toward the pinion.
Disclosed in the issue. However, this device has the following problems to be solved. First, the leaf spring obtains a spring load by bending the elastic tongue using the corner of the plug as a fulcrum, but because the end tongue is short and the distance between the fulcrum and the point of action is short, this leaf spring The change in spring load with respect to the amount of deflection is extremely large. Therefore, when assembling the rack and pinion device, slight dimensional errors or the like increase the variation in the preload force that urges the rack toward the pinion. This means that it is difficult to obtain the desired preload force.
If the preload force is too large, there is a risk that the meshing part between the pinion and the rack will wear out, and the steering wheel will become heavy during steering, which may cause discomfort to the driver. Furthermore, if the preload force is low, play may occur in the meshing portion between the rack and pinion, and there is a risk that the teeth may be damaged or worn. Moreover, since the shape of the leaf spring consists of a guide surface that follows the shape of the back of the rack shaft and end tongues at both ends, when the leaf spring deforms, the guide surface tightens the rack shaft, causing the rack shaft to This results in increased sliding resistance with the leaf spring and wear, and furthermore, when the guide surface tightens the easy shaft, the end tongue becomes difficult to bend, impairing the smooth spring action. Providing the leaf spring and plug separately has the disadvantage that when the leaf spring deforms, it may slide against the plug and cause wear, or the leaf spring may become misaligned, making it impossible to obtain proper rack shaft support. There is also.

The present invention has been made in view of these points, and one of the objects of the present invention is to reduce the number of parts, do not require precision machining, and have low manufacturing costs.
Moreover, it is an object of the present invention to provide a rack shaft support device that does not require a large space behind the rack shaft and does not cause any inconvenience while reducing the amount of protrusion of the housing.

Another object of the present invention is to provide a rack shaft support device in which even if an impactful lateral force is applied to a rack shaft, this impact is alleviated and collisions do not occur or are minimized. be.

Still another object of the present invention is to provide a rack shaft support device in which a gap is formed directly between the pusher and the rack shaft to allow and limit the amount of return of the rack shaft.

The first object mentioned above is to provide a rack shaft support device for a rack and pinion type steering device that supports the rack shaft behind the rack shaft and includes a pusher that elastically presses the rack shaft toward the pinion. A cylindrical body formed of a thin sheet metal that fits into the inner hole, and a pair of elastic tongues provided on the lower surface of the body integrally with the body, the elastic tongues being This is achieved by a rack shaft support device that is pressed against the rear surface of the rack shaft to support the rack shaft and elastically press it toward the pinion. In other words, the rack shaft is pressed in the direction of the pinion by the elastic tongue provided on the lower surface of the body of the presser, so even if the rack shaft moves back and forth with respect to the pinion, the elastic tongue only bends. The torso does not move back and forth,
Since no sliding is involved, neither high fitting precision nor good surface roughness is required. Furthermore, there is no need for highly accurate machining of the concave surface for engagement with the rack shaft. Also, since the rack shaft is pressed in the direction of the pinion by the elastic tongue of the presser, there is no need for a spring to spring the presser, reducing the number of parts, thereby reducing manufacturing costs. be done. Furthermore, since there is no need to provide a spring chamber behind the presser, it is possible to obtain a device with less partial protrusion of the housing.

And since the body is made of thin sheet metal,
The presser is lightweight, and the weight of the device can be reduced.
In addition, since a pair of elastic tongues are provided on the lower surface of the body integrally with the body, it is possible to make the size of the elastic tongues relatively large, and one end of the elastic tongue can be used as a fulcrum at the free end. The distance between the spring and the point of action is large, the change in spring load with respect to the amount of deflection of the elastic tongue is small, and a relatively light preload force can be set, and there is extremely little variation in preload force due to dimensional errors during assembly. , to eliminate wear of the meshing part between the rack and pinion and discomfort to the driver. In addition, since there is a pair of elastic tongues and their tips are free ends, the elastic tongues do not excessively tighten the rack shaft when the rack shaft retreats, and the sliding movement between the rack shaft and the elastic tongues is increased. No wear or tear. Further, since the elastic tongue piece is integrally provided on the lower surface of the body, the rack shaft can always be supported at an appropriate position without the elastic tongue piece slipping. The pair of inwardly directed elastic tongues not only press the rack shaft in the direction of the pinion, but also provide a good damping effect against the impact applied in the lateral direction of the rack shaft.

It should be noted that forming the body portion of the presser and the elastic tongue pieces integrally from a thin sheet metal by plastic working is effective for reducing manufacturing costs, especially in mass production.

The above-mentioned first and second objects are a rack and pinion type steering device that supports a rack shaft behind it and includes a pusher that elastically presses the pinion. a cylindrical body formed of a thin sheet metal that fits into the inner hole; and a pair of elastic tongues provided integrally with the body and facing inward on the lower surface of the body; The body of the presser is deformed and inserted into the inner hole of the housing to be pressed against the inner circumferential wall, and has an elastic tongue. This is achieved even more reliably by a rack shaft support device characterized in that a piece is pressed against the rear surface of the rack shaft to support the rack shaft and elastically press it toward the pinion. In other words, when a lateral force is applied to the rack shaft, the body of the presser, which is elastic and has a larger outer diameter than the inner hole of the housing when it is free, is pressed against the inner circumferential wall of the inner hole of the housing. This impact can be alleviated, collisions can be prevented, and rougher precision of the housing inner hole is allowed.

The first to third objects described above are to provide a rack shaft support device for a rack and pinion type steering device, which includes a pusher that supports the rack shaft behind the rack shaft and elastically presses the rack shaft toward the pinion.
The presser includes a cylindrical body portion formed of a thin sheet metal that fits into the inner hole of the housing, a pair of elastic tongue pieces integrally provided with the body portion and facing inward on the lower surface of the body portion;
a recess formed in the body in a direction intersecting the elastic tongue; the elastic tongue is pressed against the rear surface of the rack shaft to support the rack shaft and elastically press it toward the pinion; Furthermore, this is achieved by a rack shaft support device characterized in that the recess forms a gap of a predetermined amount between the rear surface of the rack shaft and the rear surface of the rack shaft to allow the rack shaft to retreat and at the same time to limit the amount of the retreat. be done. A recess formed in the body of the presser in a direction intersecting the elastic tongue piece forms a gap of a predetermined amount between it and the rear surface of the rack shaft to allow the rack shaft to retreat and at the same time limit the amount of retreat. The structure is simple and effective in limiting the amount of return.

Several preferred embodiments of the present invention are shown in FIGS. 1 to 10. All of these have all of the features described in the three inventions recited in the claims.

FIG. 1 is a sectional view taken along the pinion axis of the rack and pinion type steering device. The pinion 1 is rotatably supported within the housing 2, connected to a handle shaft (not shown), and rotates as the handle rotates. The rack shaft 3 intersects with the pinion 1 and is supported by a single bearing at a position remote from the pinion so as to be able to float within the housing 2, and a rack 4 formed in a portion of the rack shaft 3 meshes with the pinion 1. It reciprocates as the pinion rotates. The rack shaft is connected to a tie rod (not shown),
Its reciprocating motion deflects the wheels. A pusher 5a is housed in an inner hole 8 of a housing formed behind the rack shaft where the rack 4 and pinion 1 engage. As shown in FIGS. 2 and 3, the presser 5a includes a cylindrical body 6a formed of a thin sheet metal that fits into the housing inner hole 8, and a cylindrical body 6a formed integrally with the body on the lower surface of the body. A pair of elastic tongues 7a are provided facing each other, and the elastic tongues are pressed against the back surface of the rack shaft 3 to support the rack shaft 3 and elastically press it toward the pinion 1. The presser 5a is made by punching a thin steel plate into a predetermined shape as shown in FIG.
It is formed by folding a inward. The outer diameter of the body portion 6a when free is larger than that of the housing inner hole 8, and the split 10a makes the outer diameter of the body portion 6a larger than that of the housing inner hole 8.
It is made deformable to a smaller outer diameter, and while being deformed, it is inserted into the housing inner hole 8 and pressed against the inner circumferential wall. Therefore, it is sufficient for the housing inner hole 8 to have fairly rough dimensional accuracy, which is an important factor for reducing processing costs. Furthermore, since the body portion 6a is pressed against the housing inner hole 8, even if a lateral impact is applied to the rack shaft 3 and a lateral force is thereby applied to the pusher 5a, the pusher 5a will not move inside the housing. No collision with the hole wall. A pair of elastic tongues 7a are provided facing each other, and are engaged with the rack shaft diagonally from the left and right at a position deviated from the backside of the rack shaft 3 by a predetermined angle, so that the body portion 6a is elastically inserted into the housing inner hole 8. Coupled with the fact that they are pressed together, when a lateral impact is applied to the rack shaft 3, it is effectively alleviated and a collision is prevented. Further, the presser 5a is provided with a recess 11a formed in the body 6a in a direction intersecting the elastic tongues 7a, 7a, and the recess 11a is provided between the rear surface of the rack shaft and the rear surface of the rack shaft to allow the rack shaft to retreat and at the same time Predetermined amount of clearance to limit withdrawal
forming t′. This gap t' is created by screwing the adjusting screw 9 once until the bottom of the recess 11a contacts the back surface of the rack shaft 3, that is, until the gap is zero, and then returning the adjusting screw 9 to a predetermined angle when assembling the device. can be easily set to the desired value.

In the modification shown in FIGS. 5 and 6, the presser 5b
The body portion 6b is made into a substantially rectangular cylindrical shape, and the elastic tongue piece 7
The bent bases of b and 7b are made straight. In this case, the bending process is easy, and the spring load of the elastic tongues 7b, 7b can be easily set.
There is also the advantage that there is a wider range of spring load selection. Note that the housing inner hole 8 has a curved portion 12 of the body portion 6b,
12, 12, 12 are pressed together. Other symbols attached to the drawings correspond to the embodiments described above.

In the modification shown in FIGS. 7 and 8, the presser 5c
The seat surface 13 is located on the upper surface, that is, on the opposite side of the elastic tongue piece 7c.
was formed. In this case, the seat surface 13 provides good contact with the adjusting screw 9. Other symbols attached to the drawings correspond to the embodiments described above.

In the modification shown in FIGS. 9 and 10, the elastic tongues 7d, 7d are provided with band-shaped protrusions 14, 14. In this case, the band-like projections 14, 14 engage with the back surface of the rack shaft 3, and even if the bending angle of the elastic tongues 7a, 7a changes, the engagement position between the rack shaft 3 and the elastic tongues 7d, 7d changes greatly. The advantage is that there is nothing to do. Other symbols attached to the drawings correspond to the embodiments described above.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of an embodiment of the present invention, Fig. 2 is a sectional view of its presser, Fig. 3 is its bottom view, Fig. 4 is its developed view, and Fig. 5 is a modified example of the presser. 6 is a bottom view thereof, FIG. 7 is a sectional view of another modification of the presser, FIG. 8 is a plan view thereof, and FIG. 9 is a sectional view of another modification of the presser. FIG. 10 is a bottom view thereof, and FIG. 11 is a sectional view of the conventional example. Explanation of symbols, 1...Pinion, 2...Housing, 3...Rack shaft, 4...Rack, 5a, 5
b, 5c, 5d...presser, 6a, 6b, 6c,
6d...body of presser, 7a, 7b, 7c, 7d
... Elastic tongue piece of presser, 8 ... Inner hole of housing, 9 ... Adjustment screw, 11a, 11b, 11c,
11d...Recess in the body of the presser.

Claims (1)

[Scope of Claims] 1. A rack shaft support device for a rack and pinion type steering device that supports the rack shaft behind the rack shaft and includes a pusher that elastically presses the pinion toward the pinion, and the pusher is installed in the inner hole of the housing. It is equipped with a cylindrical body formed of a thin sheet metal that fits together, and a pair of elastic tongues that are integrally provided on the lower surface of the body and face inward, and the elastic tongues are attached to the shaft. A rack shaft support device is characterized in that it is pressed against the back surface to support the rack shaft and elastically presses the rack shaft toward the pinion. 2. In a rack shaft support device for a rack and pinion steering device that supports the rack shaft behind it and includes a pusher that elastically presses it toward the pinion, the pusher is a thin metal plate that fits into the inner hole of the housing. The body includes a cylindrical body and a pair of elastic tongues integrally provided inward on the lower surface of the body. The body of the presser is deformed and inserted into the inner hole of the housing and pressed against the inner circumferential wall, and the elastic tongue piece is pressed against the back surface of the rack shaft. A rack shaft support device characterized in that it supports a rack shaft and elastically presses it toward a pinion. 3. In a rack shaft support device for a rack and pinion type steering device that supports the rack shaft behind the rack shaft and includes a pusher that elastically presses toward the pinion, the pusher is a thin metal plate that fits into the inner hole of the housing. A cylindrical body formed, a pair of elastic tongues integrally provided on the lower surface of the body facing inward, and a pair of elastic tongues formed on the body in a direction intersecting the elastic tongues. The elastic tongue is pressed against the back surface of the rack shaft to support the rack shaft and elastically press the pinion toward the pinion, and between the recess and the back surface of the rack shaft, A rack shaft support device characterized by forming a gap of a predetermined amount to allow retreat and at the same time limit the amount of retreat.