JPH11157460A - Steering system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the working property of a bracket attached to a boot improvable and also the extent of sealability in a fitting hole part of this boot raisable, respectively. SOLUTION: A steering wheel is connected to a rack shaft shifting according to a steering operation via a mounting bracket 6 with a projection 60 installed with a fitting groove 61 on a peripheral surface and a mounting screw 7 piercing through this projection 60, and an expansible boot 3, whose both ends are set up around the rack shaft so as to be sealed up, and installed with a fitting hole 34 to be fitted in the fitting groove 61, is installed therein, and further this fitting hole 34 of the boot 3 is installed on the top of a projecting part 35 projecting toward the outside.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a center take-off type rack-and-pinion type steering device in which a middle part of a rack shaft which moves in response to a steering operation is connected to steering wheels.

[0002]

2. Description of the Related Art As one type of a steering apparatus for an automobile, a pinion connected to a steering wheel (steering wheel) is meshed with a middle portion of a rack shaft extending in the left-right direction of a vehicle body. Of the steering wheel is converted into a movement in the axial direction of the rack shaft, and this movement is transmitted to the left and right steering wheels (generally, the front wheels) to perform steering. There is a device.

[0003] Such a rack and pinion type steering apparatus further includes an end take-off type in which a pair of tie rods for connection to left and right steering wheels are separately connected to both ends of a rack shaft. Tie rods are roughly classified into center take-off types in which the tie rods are collectively connected to the middle part of the rack shaft.

The center take-off type steering device has a tie rod extending to the left and right steered wheels, but has a longer length, but can reduce the length of a rack shaft and an extendable boot provided around the rack shaft. Further, it has an advantage that the degree of freedom in setting the relative positional relationship between these and the steered wheels is large, and is adopted in some types of vehicles in which the arrangement of the boots is restricted. The boot is formed in a bellows shape with a synthetic resin or rubber, and seals both ends to prevent foreign matters such as dust and water from entering around the rack axis.

In the center take-off type steering apparatus as described above, it is necessary to connect a pair of left and right tie rods to a middle part of the rack shaft moving inside the boot.
As described in Japanese Utility Model Laid-Open No. 57-174275 and U.S. Pat. It is realized by attaching to.

The bracket has a cylindrical projection through which the mounting screw is inserted. As shown in FIG. 10, the outer peripheral surface of the projection is formed as a tapered surface having a smaller diameter from the base end toward the distal end as shown in the above-mentioned U.S. Pat. No. 4,601,602. An annular fitting groove B is provided in the middle of the tapered surface.

A through hole of the boot C is provided with a fitting hole D having a diameter smaller than the outer shape of the projection A, and the projection A of the bracket E is forcibly pushed into the fitting groove B from the tip of the projection A. Thereby, the fitting hole D is fitted into the fitting groove B, the sealing property of the fitting hole D of the boot C is enhanced, and foreign matters such as dust and water enter the boot C from the fitting hole D. I'm making it difficult.

[0008]

However, in the above-described steering apparatus, since only the fitting hole D is provided on the outer peripheral surface of the boot C, the projection A of the bracket E is fitted to the fitting hole D.
When forcibly pushed into the boot C, the area around the fitting hole D of the boot C is elastically deformed and bent inward in the boot C. For this reason, even if the operation of forcibly pushing the projection A into the fitting hole D is performed, the fitting hole D is hardly fitted into the fitting groove B, and the workability of attaching the bracket E to the boot C is poor.
There was a problem that the cost was high.

Further, the fitting hole D provided on the outer peripheral surface of the boot C is merely formed to have a diameter equal to or larger than the outer diameter of the fitting groove B. When fitted in the fitting groove B, the fitting hole D cannot be pressed against the outer peripheral surface of the fitting groove B, and there is room for improvement in the sealing property of the fitting hole D portion of the boot. .

The present invention has been made in view of such circumstances, and in a center take-off type rack-and-pinion type steering apparatus, a fitting hole of a boot is outwardly provided through a projection around the fitting hole. An object of the present invention is to provide a steering device that can easily fit a fitting hole into a fitting groove by arranging the same, and can further enhance sealing of a fitting hole portion of a boot. I do.

[0011]

According to a first aspect of the present invention, there is provided a steering apparatus including a mounting bracket having a projection provided with a fitting groove on an outer peripheral surface thereof, and a rack shaft which moves in response to a steering operation. A steering wheel is connected via mounting screws to be mounted, and is arranged so that both ends are sealed around the rack shaft, and is provided with a fitting hole fitted in the fitting groove. In the steering device provided with a boot capable of performing the following, the fitting hole is provided at a top of a protruding portion that protrudes outward.

A steering device according to a second aspect of the invention is characterized in that the projecting portion is formed in a tapered shape having a smaller diameter from a base end toward a tip end.

In the first invention and the second invention, since the fitting hole is provided at the top of the projecting portion projecting outward, the tip of the projection is inserted into the fitting hole of the boot. By pressing, the projection around the fitting hole is elastically deformed in the radially expanding direction and bent in a tapered shape toward the inside of the boot in a state where the tip of the projection is in contact with the fitting hole.

With the fitting hole elastically deformed, the pressing of the projection is temporarily stopped, the projection is once pulled in the direction opposite to the pressing direction, and the projection is pressed again with the fitting hole positioned outside the boot. I do. In this case, the protruding portion around the fitting hole is elastically deformed by the first press, and is newly pressed in a state where the elastic allowance is reduced. In other words, the protrusion is harder than the initial elasticity. Since it is further pressed from the state where it is in the state, the projecting portion generates a tension phenomenon with respect to the second pressing, and the projecting portion is elastically deformed in the radially expanding direction without bending the projecting portion inside the boot due to the projecting phenomenon. By deforming, the fitting hole can be securely fitted in the fitting groove.

As described above, since the protrusion of the boot is elastically deformed in the radially increasing direction in a stepwise manner by pressing the projection, the fitting of the fitting hole into the fitting groove can be easily performed. The operation of attaching the bracket to the boot can be easily performed, and the cost can be reduced.

Moreover, since the fitting hole is provided at the top of the protruding portion, even when the fitting hole is formed to have a hole diameter equal to or larger than the outer diameter of the fitting groove, the bracket is mounted on the rack by the mounting screw. When the projection is attached to a shaft and the projection becomes flat, the projection can be elastically deformed in the radially reduced direction, so that a fitting hole can be pressed against the fitting groove,
The sealing performance of the fitting hole of the boot can be easily improved.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings showing the embodiments. FIG. 1 is an explanatory view showing a process of fitting a fitting hole of a steering device according to the present invention into a fitting groove, FIG. 2 is a vertical sectional front view showing a configuration of a main part, and FIG. Sectional view, FIG. 4 shows the boots,
(a) is a vertical front view with some parts omitted, (b) is a bottom view, (c)
5 is a front view, FIG. 5 is a vertical side view, FIG. 6 is a bottom view of a rack shaft, and FIG. 7 is a cross-sectional view of the entire steering device.

The rack-and-pinion type steering device shown in FIG. 7 has a pinion shaft 1 having one end linked to a steering wheel (steering wheel) and a pinion (not shown) provided at the other end. Rack teeth (not shown) that mesh with the pinion are provided, and a rack shaft 2 extending in the left-right direction of the vehicle body, and a cylindrical expansion and contraction disposed around the rack shaft 2 and sealed at both ends. Possible boots 3 and these rack shafts 2
And a rack housing 4 interposed between the boot 3 and the rack shaft 2 to support the rack shaft 2 and the boot 3, and a pair of tie rods 5,
A bracket 6 for holding the base end of the bracket 5 and a fitting groove 6 provided on the bracket 6 at a predetermined interval.
1 and a pair of projections 60
This is a center take-off type steering device including mounting screws 7, 7 which are detachably mounted on the rack shaft 2 through the rack shaft 2.

As shown in FIG. 7, the rack shaft 2 is slidably supported in the axial direction inside the cylindrical rack housing 4 having one end closed. Also,
At one end of the rack shaft 2, a pair of mounting holes 21 and 21 for mounting the bracket 6 are formed at predetermined intervals in the axial direction. As shown in FIG. 2, these mounting holes 21 and 21 are inclined so as to intersect with the axial direction of the rack shaft 2, and have flat receiving seats 22 and 2 in their openings.
2 are provided.

As shown in FIG. 7, the rack housing 4 is formed in a bottomed cylindrical shape having one end closed and the other end open, and a pinion is provided at a middle portion of the closed side so as to intersect with the pinion. A housing 8 is provided in series, and the pinion shaft 1 is supported inside the pinion housing 8 so as to be rotatable around an axis. The rotation of the pinion shaft 1 slides in the axial direction of the rack shaft 2. It is converted to motion.

As shown in FIG. 7, a window 41 for moving the bracket 6 with respect to the rack housing 4 is provided in the middle of the open side of the rack housing 4. Covered with the boots 3, garbage,
Foreign matter such as water is prevented from entering the rack housing 4 from the window hole 41.

As shown in FIG. 2, the bracket 6 has a pair of holding pieces 62 and 63 for holding the base end of the tie rod 5.
And a connecting piece 6 for connecting one end of each of the holding pieces 62 and 63.
4 and a pair of cylindrical projections 60, 60 fixed to one of the holding pieces 62 at a predetermined interval, and a through hole 65 corresponding to a central hole of the projections 60, 60 is provided in each of the holding pieces. 62 and 63 are provided. And these through holes 6
The mounting screw 7 is inserted through the center hole of the protrusion 5 and the projection 60. As shown in FIG. 1, the protrusions 60, 60 are formed in a tapered shape having a smaller diameter from the base end to the front end, and annular fitting grooves 61, 60 are formed on the outer peripheral surface of the base end portions of the protrusions 60, 60. 61 are provided.

The boot 3 is made of a flexible synthetic resin, rubber, or the like. As shown in FIGS. A connecting cylinder portion 32 for connecting the portions 31, 31;
A flat receiving portion 33 facing the bracket 6 is provided integrally with the connecting tubular portion 32. In addition, the elastic part 31,
At both ends of the rack housing 4, the mounting rings 9
It is detachably attached to and is sealed.

As shown in FIGS. 4 (a) and 4 (b), the receiving portion 33 is provided with fitting holes 34 which fit into the fitting grooves 61 of the projections 60. . This fitting hole 3
4, 34 are projecting portions 35, 35 projecting outward.
Is provided at the top. The protrusions 35, 35 are
Similarly to 0, 60, it is formed in a tapered shape having a smaller diameter from the base end to the distal end, and the fitting holes 34, 34 are formed to have a slightly smaller diameter than the outer diameter of the fitting grooves 61, 61. Have been.

As shown in FIGS. 2 and 4, between the fitting holes 34, 34 of the receiving portion 33, a clamping portion 36 projecting from the inner surface and the outer surface of the receiving portion 33 is provided. When mounting the bracket 6 by tightening the screws 7, 7,
Is clamped between the bracket 6 and the rack shaft 2, the clamping portion 36 is elastically deformed by the clamping, and the elastic deformation of the clamping portion 36 is transmitted to the bases of the protruding portions 35, 35 to form the fitting hole 3.
4, 34 are pressed into the fitting grooves 60, 60, and the fitting holes 34, 3 are pressed.
The sealing performance of four parts can be further enhanced.

The steering apparatus according to the embodiment shown in FIG. 7 is configured as a power steering apparatus for assisting the sliding of the rack shaft 2 by hydraulic pressure, and a power cylinder for applying an assisting force to the rack shaft 2. A piston rod 11 coaxially connected to one end of the rack shaft 2 extends into a cylinder 12 connected to the open end of the rack housing 4 and a piston 13 attached to the extended end. Is slidably fitted inside the cylinder 12 via a seal ring 14 wound around the outer periphery thereof.

The cylinder 12 is a closed-end cylindrical member having a closed end opposite to the connection end with the rack housing 4.
On the connection side with the rack housing 4, a seal holder 16 for holding the seal member 15 is mounted inside.
The piston rod 11 is extended inside the cylinder 12 with the middle part thereof sealed in a liquid-tight manner by the seal member 15.

As described above, the power cylinder 10 has a pair of oil chambers sealed on both sides of the piston 13 in a liquid-tight manner inside the cylinder 12, and external hydraulic pressure is supplied to these oil chambers. The piston rod 11 is pushed and pulled in the axial direction by a pressure difference generated on both sides of the piston 13 in response to the supply, and the axially moving force is applied to the rack shaft 2 connected to the base end of the piston rod 11. It is configured to be added.

The oil chambers on both sides of the piston 13
, Each of which is connected to a corresponding position outside the
17 are connected to a pair of oil feed ports 81 and 82 provided outside the pinion housing 8. The pinion housing 8 performs a supply / discharge operation of hydraulic pressure in accordance with a steering torque applied to the pinion shaft 1 in accordance with a steering operation for steering, and sends the oil supply port to one of the oil supply ports 81 and 82. A hydraulic control valve is built-in, and the hydraulic pressure delivered to the oil supply ports 81 and 82 is supplied to the power cylinder 10 through the oil supply pipes 17 and 17, and the hydraulic pressure generated according to the supply is applied to the rack shaft 2. In addition, steering that occurs as described above is assisted.

When mounting the tie rods 5, 5 of the center take-off type steering device configured as described above to the rack shaft 2, the projections 60, 60 are fitted into the fitting holes 34, 34 of the boot 3, and the bracket 6 is attached. Attach it to boot 3.

In this case, as shown in FIG.
The distal end of the projection 60 is inserted into the fitting holes 34 of the boot 3 and pressed, so that the projections 60, 60 are in contact with the fitting holes 34, 34 around the fitting holes 34, 34. 1 while elastically deforming in the radially expanding direction.
As shown in (b), it is bent in a tapered shape inside the boot 3.

When the fitting holes 35, 35 are elastically deformed, the pressing of the projection is temporarily stopped, and the projection 6 is stopped as shown in FIG.
0, 60 is once pulled in the direction opposite to the pressing direction, and FIG.
The fitting holes 34, 34 are positioned outside the boot 3 as shown in FIG. In this state, the protrusion is pressed again as shown in FIG.

In this case, the protrusions 35 around the fitting holes 34 are elastically deformed by the first pressing, and are newly pressed in a state where the allowable elasticity is reduced. In other words, since it is further pressed from the state where it is harder than the initial elasticity, the projecting portions 35, 35 generate a tension phenomenon with respect to the second pressing, and the projecting portions 35, 35 are caused by the tension phenomenon. By elastically deforming 35 in the radially expanding direction without bending the inside of the boot 3, the fitting holes 34 can be securely fitted into the fitting grooves 61 (FIG. 1E).

As described above, since the projections of the boot are stepwise elastically deformed in the radially expanding direction by pressing the projections 60, 60, the fitting of the fitting holes 34, 34 into the fitting grooves 61, 61 is simplified. Can be done. Therefore, the work of attaching the bracket 6 to the boot 3 can be easily performed, and the cost can be reduced.

After the bracket 6 is attached to the boot 3 as described above, the base ends of the tie rods 5, 5 are
Between the holding pieces 62, 63 of the
The mounting screws 7, 7 are inserted through the through-hole 65 of the rack shaft 63, the through-hole 51 at the base end of the tie rod 5, and the center hole of the projections 60, 60, and the mounting screws 7, 7 are inserted into the mounting holes 21, 21 of the rack shaft 2.
, The steering wheel can be attached to the rack shaft 2 via the tie rods 5, 5, the bracket 6, and the attachment screws 7, 7.

When the bracket 6 is mounted on the rack shaft 2 by the mounting screws 7, 7 as shown in FIG. 1F, the projections 35, 35 become flat, and the projections 35, 35 Elastically deformed. As a result, the fitting holes 34, 3
4 can be pressed into the fitting grooves 61, 61, and the sealing performance of the fitting holes 34, 34 of the boot 3 can be easily improved.

The sliding movement of the rack shaft 2 in both directions within the window hole 41 is allowed by the expansion and contraction of the expansion and contraction portions 31 on both sides of the connecting cylinder 32.

In the embodiment described above, a structure in which the bracket 6 is mounted on the rack shaft 2 using two mounting screws 7, 7 has been described. Installation is as shown in FIG.
This may be performed using the mounting screws 7.

As shown in FIGS. 1 and 7, mounting screws 7 for mounting the bracket 6 to the rack shaft 2 are provided.
In addition to the configuration in which the rack shaft 2 is inclined so as to intersect with the axial length direction, the rack shaft 2 may be configured to be substantially orthogonal to the axial length direction as shown in FIG. 8 and 9 are basically the same as the embodiments shown in FIGS. 1 to 7, and therefore, common reference numerals are used, and detailed description and drawings are omitted.

[0040]

As described above, according to the first and second aspects of the present invention, since the fitting hole is provided at the top of the protruding portion projecting outward, the projection is pressed into the fitting hole. Then, the projection around the fitting hole is elastically deformed in the radially expanding direction and bent toward the inside of the boot, and in this state, the pressing of the projection is temporarily stopped, and the projection is temporarily pulled in the direction opposite to the pressing direction to be fitted. By pressing the protrusion again with the mating hole positioned outside the boot, the protrusion is elastically deformed in the radial direction without bending the protrusion inside the boot, and the fitting hole is securely inserted into the fitting groove. Can be fitted. Therefore, the fitting hole can be fitted into the fitting groove by a simple operation of only pressing the projection stepwise, so that the operation of attaching the bracket to the boot can be easily performed, and the cost can be reduced. be able to.

Further, since the fitting hole of the boot is provided at the top of the protruding portion, even when the fitting hole is formed to have a hole diameter equal to or larger than the outer diameter of the fitting groove, the bracket can be fixed by the mounting screw. Can be elastically deformed in the radially decreasing direction when the projection is flattened by being attached to the rack shaft. Therefore, the fitting hole can be pressed against the fitting groove, and the sealing property of the fitting hole of the boot can be easily improved.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a process of fitting a fitting hole of a steering device according to the present invention into a fitting groove.

FIG. 2 is a longitudinal sectional front view showing a configuration of a main part of the steering device according to the present invention.

FIG. 3 is an exploded sectional view of a boot and a bracket of the steering device according to the present invention.

FIG. 4 shows a boot of the steering device according to the present invention,
(a) is a vertical front view with some parts omitted, (b) is a bottom view, (c)
Is a front view.

FIG. 5 is a vertical sectional side view of a boot of the steering device according to the present invention.

FIG. 6 is a bottom view of the rack shaft of the steering device according to the present invention.

FIG. 7 is an overall sectional view of a steering device according to the present invention.

FIG. 8 is a sectional view of a main part showing another embodiment of the steering device according to the present invention.

FIG. 9 is a sectional view of a main part showing still another embodiment of the steering device according to the present invention.

FIG. 10 is a sectional view of a steering device showing a conventional example.

[Explanation of symbols]

 2 Rack shaft 3 Boot 34 Fitting hole 35 Projection 6 Bracket 60 Projection 7 Mounting screw

Claims (2)

[Claims] 1. A steering wheel is connected to a rack shaft that moves in accordance with a steering operation via a mounting bracket having a projection provided with a fitting groove on an outer peripheral surface and a mounting screw passing through the projection. And a steering device provided with an expandable and contractible boot provided with a fitting hole to be fitted in the fitting groove, wherein the boot is arranged so that both ends are sealed around the rack shaft. A steering device, wherein the fitting hole is provided at a top of a protruding portion protruding outward. 2. The steering device according to claim 1, wherein the projecting portion is formed in a tapered shape having a smaller diameter from a base end toward a tip end.