GB2287923A

GB2287923A - Steering lock apparatus

Info

Publication number: GB2287923A
Application number: GB9505198A
Authority: GB
Inventors: Yasuhisa Yamada
Original assignee: NSK Ltd
Current assignee: NSK Ltd
Priority date: 1994-03-28
Filing date: 1995-03-15
Publication date: 1995-10-04
Anticipated expiration: 2015-03-15
Also published as: DE19511374A1; JPH07257322A; DE19511374C2; GB9505198D0; GB2287923B

Description

STEERING LOCK APPARATUS 2287923

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a steering lock apparatus that locks a steering wheel (or keeps it from rotating) for antitheft of car in the state where an ignition key is taken out of a key hole.

Related Backqround Art For antitheft of car, many cars are provided with the steering lock apparatus. Such steering lock apparatus is so arranged that when the ignition key is turned to a lock position in order to be drawn out of the key hole, a key lock collar fixed to the steering shaft rotated by the steering wheel comes to engage with a lock key supported on a stationary steering column. This engagement secures the steering shaft to the steering column, thereby stopping rotation of the steering shaft.

Meanwhile, height adjusting apparatus of the steering wheel as called as tilt steering apparatus is also conventionally widely used to change the height of the steering wheel depending upon the physique or a driving posture, etc. of driver. Fig. 4 shows an example of such tilt steering apparatus. A support bracket 4 fixed to the car body supports a steering column 3 through which a steering shaft 2 to be rotated r through manipulation of a steering wheel 1 fixed at an upper end (rear end) thereof is inserted. The steering column 3 is separated into two parts, an upper steering column 5 and a lower steering column 6, at a border of the support bracket 4. The front end of the upper steering column 5 out of the two parts is rotationally supported by a pair of left and right transverse shafts 7 to the support bracket 4.

On the other hand, the steering shaft 2 is separated into two parts, an upper steering shaft 8 and a lower steering shaft 9. The two parts 8, 9 of the steering shaft are connected to each other through a universal joint 10 (Fig. 5 and Fig. 6 as detailed later). The displacement center of the universal joint 10 is located on an extension line of the transverse shafts 7. Accordingly, a rotational force is smoothly transmitted between the upper steering shaft 8 and the lower steering shaft 9, irrespective of a displacement of the upper steering shaft 8 due to a displacement of the upper steering column 5 about the transverse shafts 7.

For adjusting the height of the steering wheel 1, a tilt lever 11 is manipulated to release a holding force of the upper steering column 5 to the support bracket 4. Rocking the upper steering column 5 in this state about the transverse shafts 7, 7, the height position of the steering wheel 1 is adjusted. After z that, the tilt lever 11 is manipulated in the opposite direction to hold (or secure) the upper steering column 5 to the support bracket 4.

Basic structures for the steering lock apparatus for antitheft to be incorporated in the tilt steering apparatus in the above structure and operation, are classified into the structure as shown in Fig. 5 and the structure as shown in Fig. 6. In the structure shown in Fig. 5, a cylindrical key lock collar 12 is fixed by welding etc. to a peripheral surface of the upper steering shaft 8 inside the upper steering column 5. A key lock hole 13 is formed in the key lock collar 12 so as to extend in the axial direction (in the horizontal direction in Fig. 5).

Further, a through hole 14 is formed in a portion of the upper steering column 5 and as opposed to an outer peripheral surface of the key lock collar 12. Then a distal end portion of key lock 20 (Fig. 6 as detailed below) arranged as slidable inside the through hole 14 is arranged to enter the key lock hole 13, based on manipulation of an ignition key 21 (Fig. 6). A rocking bracket 15 bifurcated at the front end is fixed by welding etc. to the front end of the upper steering column 5, while the rear end portion of the lower steering column 6 is fixed by welding etc. to the support bracket 4. Then the two brackets 15, 4 are rotationally supported through the transverse shafts 7, 7.

In the case of the structure shown in Fig. 6, the key lock collar 12 is fixed to a peripheral surface of the lower steering shaft 9 inside the lower steering column 6. Corresponding to it, a through hole 14 is formed in a part of the lower steering column 6, and the distal end of lock key 20 arranged as slidable inside the through hole 14 is arranged to enter the key lock hole 13, based on manipulation of ignition key 21. Reference numeral 17 designates a holding barrel an internal end of which is supported by the through hole 14, and the lock key 20 is arranged as slidable inside the holding barrel 17.

In the case of the structure of the first example shown in Fig. 5 out of the steering lock apparatus in the above structure and operation, however, the position of the key hole for the ignition key to be inserted thereinto changes with adjustment of the height position of the steering wheel. Because of this, the operability of the ignition key is not always good. In the case of the second example shown in Fig. 6, the position of the key hole is stationary even with adjustment of the height position of the steering wheel, thereby never degrading the operability of the ignition key. Instead, the following problem occurs.

Namely, when the steering wheel 1 (Fig. 4) is to be strongly rotated in such a state that the distal z end of the lock key 20 is present in the key lock hole 13 of the key lock collar 12 so as to stop rotation of the steering wheel 1, the lower steering shaft 9 and universal joint 10 are bent in the direction away from the lock key 20, based on torsional stress exerted on the lower steering shaft 9 through the universal joint 10. There is a possibility that the engagement between the lock key 20 and the key lock hole 13 is destroyed or a possibility that a_bearing of the universal joint 10 slips off. When the lock key 20 is thus disengaged from the key lock hole 13, the steering wheel 1 becomes free to rotate, thus disabling the antitheft effect. When the bearing of universal joint 10 slips off, the torque transmission of steering wheel 1 is disabled.

To solve such problems, Japanese Laid-open Utility Model Application No. 4-2758 describes the structures as shown in Fig. 7 and Fig. 8. First, in the case of the structure shown in Fig. 7, a ring displacement preventing member 18 is fixed to a portion near the key lock collar 12, on an inner periphery of an.opening portion at the rear end of the lower steering column 6. An inner edge of the displacement preventing member 18 is set as close to the outer peripheral surface of the lower steering shaft 9 in a normal state (where no large torsional stress is applied on the lower steering shaft g).

In the steering lock apparatus as arranged in the above structure, when the lower steering shaft 9 tends to bend in the direction perpendicular to the axis, the inner edge of the displacement preventing member 18 fixed to the inner peripheral surface of the lower steering column 6 comes into contact with the outer peripheral surface of the lower steering shaft 9. This can prevent the lower steering shaft 9 from bending too much, thereby preventing disengagement of the lock key 20 (Fig. 6) from the key lock hole 13 or slip-off of the bearing of universal joint 10.

In the case of the structure shown in Fig. 8, the displacement preventing member 18 on the inner peripheral surface of the opening portion at the rear end of the lower steering column 6 is omitted, but instead, a ring displacement preventing member 19 is fixed at a position near the key lock collar 12 on the outer peripheral surface of the lower steering shaft 9. In addition to it, the outer peripheral edge of the displacement preventing member 19 is set as close to the inner peripheral surface of the lower steering column 6. In the case of this structure shown in Fig. 8, if strong stress is applied on the lower steering shaft 9 in the direction to twist it, the outer peripheral edge of the displacement preventing member 19 comes into contact with the inner peripheral surface of the lower steering column 6, thereby preventing the lower steering shaft 9 from largely bending.

SUMMARY OF THE INVENTION

The conventional structures shown in Figs. 7 and 8 need the extra displacement preventing member 18, 19 for stopping bending of the steering shaft 9 so as to prevent the lock key 20 from being disengaged from the key lock hole 13 or to prevent the bearing of universal joint 10 from slipping off, which was a cause of cost increase. The present invention has been accomplished to avoid the cost increase due to the prevention of bending of the steering shaft 9, by devising the shape of constituents of the steering apparatus.

The steering lock apparatus according to the present invention is so arranged, similarly as the conventional steering lock apparatus as described previously, that the apparatus comprises an upper steering shaft to a rear end of which a steering wheel is fixed, an upper steering column through which the upper steering shaft is inserted so as to be rotatable, pair of left and right transverse shafts arranged on same axis and supporting a front end of the upper steering column so as to be rockable, a universal joint provided at a front end of the upper steering shaft, a lower steering shaft of a circular cross section a rear end of which is connected to the universal joint, a tubular lower steering column through which the lower steering shaft is inserted so as to be rotatable, a key 8 lock collar fixed to an outer peripheral surface of the lower steering shaft at a position inside the lower steering column and having a key lock hole formed in a part of the outer peripheral surface thereof, a through hole formed in a part of the lower steering column at a position where said through hole can be aligned with the key lock hole, a key cylinder fixed to the lower steering column so that an inner end portion thereof is aligned with an inside portion of the through hole, and a lock key set inside the key cylinder so as to be slidable in the direction of the diameter of the lower steering column. The lock key is so arranged that the distal end portion thereof goes into the key lock hole, based on manipulation of the ignition key.

In particular, the steering lock apparatus of the present invention is provided with a second through hole formed in a part of the lower steering column on the opposite side in the diameter direction to the through hole, a bracket coupled and fixed to a base end portion of the key cylinder and securing the key cylinder to the lower steering column while embracing the lower steering column together with the base end portion, and a projection provided in a stationary manner in a portion aligned with the second through hole, on an inner peripheral surface of a middle portion of the bracket. The tip of the projection is set as close to the outer peripheral surface of the key lock collar.

In the steering lock apparatus of the present invention in the above-described structure, when great stress is applied on the lower steering shaft in the twisting direction, the stationary projection provided in the bracket comes into contact with the outer peripheral surface of the key lock collar, whereby the lower steering shaft securing the key lock collar can be prevented from largely bending. The bracket is a component used for supporting and securing the key cylinder to the lower steering column, but is not a component separately prepared for preventing the bending of the lower steering shaft. Accordingly, the invention can obviate labor and time for preparing an extra component for prevention of bending and for assembling them, thus decreasing the production costs of the steering lock apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS 20 Fig. 1 is a drawing to show an embodiment of the present invention, corresponding to the cross section along V-V in Fig. 4; Fig. 2 is an enlarged drawing of section B in Fig. 1;

Fig. 3 is a cross section along III-III in Fig.

2; Fig. 4 is a side view to show an example of conventionally known steering apparatus; 1 Fig. 5 is a drawing to show a first example of the conventional structure, corresponding to the cross section along V-V in Fig. 4; Fig. 6 is a drawing to show a second example of the conventional structure, similar to Fig. 5; Fig. 7 is a drawing to show a third example of the conventional structure, similar to Fig. 5; and Fig. 8 is a drawing to show a fourth example of the conventional structure, similar to Fig. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Figs. 1 to 3 show an embodiment of the present invention. A support bracket 4 is fixed to the car body, for example to the lower surface of the dash board, as shown in Fig. 4 described previously. A rocking bracket 15 is rotationally supported through a pair of left and right (upper and lower in Fig. 1) transverse shafts 7, 7 on the support bracket 4. The rocking bracket 15 has a support wall 16 at a rear end thereof. In the central portion of the support wall 16, the upper steering column 5 penetrates the support wall 16 and the upper steering column 5 is fixed by welding etc. to the support wall 16. Inside the upper steering column 5 an upper steering shaft 8 is rotatably supported through a pair of front and rear rolling bearings 22, 22.

On the other hand, a lower steering column 6 is 1 - 11 set in the central portion of a front wall 23 of the support bracket 4 so as to penetrate the front wall 23. The lower steering column 6 is fixed by welding etc. to the front wall 23. Inside the lower steering column 6 a lower steering shaft 9 is set therethrough so as to be rotatable. The front end of the upper steering shaft 8 is coupled through a universal joint 10 with the rear end of the lower steering shaft 9. The displacement center of the universal joint 10 is located on an extension line of the pair of transverse shafts 7, 7, so that a rotational force can be transmitted between the two steering shafts 8 and 9, regardless of a displacement of the upper steering shaft 8 about the transverse shafts 7, 7.

Further, a key lock collar 12 is fixed on an outer peripheral surface of the lower steering shaft 9 inside the lower steering column 6. The key lock collar 12 has a key lock hole 13 extending in the axial direction (or in the horizontal direction in Fig. 1). Also, a though hole 14 is formed in a part of the lower steering column 6 and at a position as opposed to the key lock hole 13. An inner end (the lower end in Figs. 1 to 3) of a key cylinder 24 is supported inside the through hole 14. The outer half of the key cylinder 24 penetrates a side wall 25 of the support bracket 4 to project from the outer side surface of the side wall 25. Inside the key cylinder 24 a lock key 20 is set so as to be slidable and the distal end of the lock key 20 is arranged to be elastically pressed against the outer peripheral surface of the key lock collar 12, based on manipulation of the ignition key 21 (Fig. 6). The lock key 20 is so arranged that the distal end thereof goes into the key lock hole 13 in a state where the tip face thereof is aligned with the key lock hole 13.

Provided at the inner end portion of the key cylinder 24 is a mount portion 26 for securing the key cylinder 24 to the lower steering column 6. The mount portion 26 is formed in a substantially semi-circular shape and an inner peripheral surface thereof can be in contact with the outer peripheral surface of the lower steering column 6. Further, flange portions 27, 27 are formed at the both end portions of the mount portion 26 and thread holes 28, 28 are formed in parallel with each other in the both flange portions 27, 27. In order to secure the key cylinder 24 to the outer peripheral surface of the lower steering column 6 at the rear end thereof, the outer peripheral surface at the rear end is sandwiched between the inner peripheral surface of the mount portion 26 and the inner peripheral surface of a bracket 29 as detailed below.

This bracket 29 is formed by pressing a metal plate, for example a steel plate, and the inner peripheral surface thereof can be in contact with the outer peripheral surface at the rear end. A bent edge 1 is formed at the peripheral edge of the bracket 29 so as to be bent on the opposite side to the mount portion 26, thereby assuring the stiffness of the bracket 29. Further, flange portions 30, 30 are formed in the both end portions of the bracket 29, and circular holes 31, 31 are formed at positions where they can be aligned with the thread holes 28, 28 as described above and in parts of the respective flange portions 30, 30 so that bolts 32, 32 as described below can be inserted thereinto.

Further, a second through hole 33 is formed in a portion of the lower steering column 6 on the opposite side in the diameter direction, as opposed to the through hole 14 for the key cylinder 24 to be set therein. A projection 34 which can be set in the second through hole 33 is formed in the center portion of the inner peripheral surface of the bracket 29 and at the position where it is aligned with the second through hole 33.

The following describes work for securing the key cylinder 24 to the rear end of the lower steering column 6, using the bracket 29 having the abovedescribed shape. First, the inner peripheral surface of the mount portion 26 provided in the key cylinder 24 is set as opposed to the outer peripheral surface of the lower steering column 6 at the rear end thereof. After that, the projecting portion from the inner - ' 1 peripheral surface of the mount portion 26 at the inner end portion of the key cylinder 24 is let to fit in the through hole 14 and the inner peripheral surface of the mount portion 26 is brought into contact with the outer peripheral surface of the lower column 6 at the rear end. Then the bracket 29 is brought toward the outer peripheral surface of the lower column 6 at the rear end from the opposite side to the mount portion 26.

Then the projection 34 is set in the second through hole 33 and the inner peripheral surface of the bracket 29 is brought into contact with the outer peripheral surface of the lower column 6 at the rear end.

After the inner peripheral surface of the bracket 29 comes into contact with the outer peripheral surface of the lower column 6 at the rear end in this manner, the bolts 32, 32 set through the circular holes 31, 31 are screwed into the respective thread holes 28, 28 to be further tightened. As a result, the mount portion 26 and the inner peripheral surface of the bracket 29 are strongly urged against the outer peripheral surface of the lower steering column 6 at the rear end thereof, whereby the key cylinder 24 is firmly fixed to the lower steering column 6. In this state, the tip face of the projection 34 formed in the center portion of the inner peripheral surface of the bracket 29 is located as close to the outer peripheral surface of the key lock collar 12.

In the case of the steering lock apparatus of the present invention in the above-described structure, the displacement is limited on the opposite side to the key lock hole 13 of the key lock collar 12, based on contact of the projection 34 with the outer peripheral surface of the key lock collar 12. Accordingly, the key lock collar 12 will never be displaced so much in the direction away from the lock key 20. Therefore, even if a large force is applied on the lower steering shaft 9 through the steering wheel 1 (Fig. 4) in the steering lock state, the disengagement of the tip end of the lock key 20 out from the key lock hole 13 or the slip-off of the bearing of the universal joint 10 will not occur.

In addition, the bracket for preventing the bending of the lower steering shaft 9 in the present invention is a component used for supporting and fixing the key cylinder 24 to the lower steering column 6, but is not a component separately prepared for preventing bending of the lower steering shaft 9. Accordingly, there is no need to prepare an extra component for preventing the bending, thus decreasing the production costs of the steering lock apparatus.

Because of the structure and operation as described above, the steering lock apparatus of the present invention can surely stop rotation of the steering wheel while the position of the key hole of 1 1 1 the ignition key is kept fixed. Also, it can prevent skidding rotation of the steering wheel due to a damage on the universal joint. This can improve the operability of the ignition key and can also improve the reliability of the steering lock apparatus at the same time. In addition, the production costs of the steering lock apparatus are not increased.

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Claims

CLAIMS: 1. A steering lock apparatus comprising: an upper steering shaft

to a rear end of which a steering wheel is fixed; an upper steering column through which the upper steering shaft is inserted so as to be rotatable; a pair of left and right transverse shafts arranged on a same axis and supporting a front end of the upper steering column so as to be rockable; a universal joint provided at a front end of said upper steering shaft; a lower steering shaft a rear end of which is connected to the universal joint; a tubular lower steering column through which the lower steering shaft is inserted so as to be rotatable; a key lock collar fixed on an outer peripheral surface of said lower steering shaft in a portion inside said lower steering column and having a key lock hole formed in a part of said outer peripheral surface; a through hole formed in a part of said lower steering column at a position where said through hole can be aligned with the key lock hole; a key cylinder fixed to said lower steering column so that an inner end potion thereof is aligned with an inside portion of the through hole; a lock key set through and inside the key cylinder so as to be slidable in a direction of a diameter of said lower steering column, said lock key being arranged so that a distal end portion thereof goes into said key lock hole, based on manipulation of an ignition key; a second through hole formed in a portion of said lower steering column on the opposite side to said through hole in the direction of the diameter; a bracket coupled in a stationary manner with a base end portion of said key cylinder and securing said key cylinder to the lower steering column while embracing said lower steering column together with the base end portion; and a projection provided in a stationary basis in a portion aligned with said second through hole on an inner peripheral surface of a middle portion of the bracket, a tip end of said projection being set as close to an outer peripheral surface of said key lock collar.

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2. A steering lock arrangement for preventing or restricting rotation of a steering shaft relative to a steering column within which said shaft extends, said arrangement comprising a lock body clamped to the steering column by a clamping device and having a bolt which in a locking position thereof has a free end portion received within a recess associated with the steering shaft to prevent or restrict rotation of the shaft relative to the column, said clamping device including an abutment which projects through an aperture in said column for engaging said shaft for preventing movement thereof away from said bolt end portion which would allow said bolt to escape said recess when said bolt is in its locking position.
3. A steering lock apparatus substantially as hereinbefore described with reference to Figures 1 to 3 of the accompanying drawings.