DESC:ELECTRONIC STEERING COLUMN LOCK MECHANISM

Field of the invention:

The present invention generally relates to an automobile steering lock mechanism and more particularly, to an electronic steering column lock mechanism with a unique lower housing providing mounting and locating feature for the components of the mechanism.

Background of the invention:

Automobile vehicles need to be protected against unwanted use and theft. Steering locks are widely used as an anti-theft device, which are fitted to a steering column generally below a steering wheel. Nowadays, conventional mechanical steering column locks of the prior art are being replaced by electronic keys. The lock is combined with an ignition switch and engaged and disengaged electronically from an electronic control unit of the vehicle. Further, conventional mechanical steering locks are replaced by electronic steering wheel locks. The patent CN205256274 discloses an electronic steering column lock that is driven by a motor and a gear train and responds to locking and de-blocking location of hall sensor to realize locking and the unblock of electronic steering column lock. The gear train of steering column lock mechanism disclosed in CN205256274 has two gears, which has limitations in meeting various torque and transmission requirements. Secondly, in current designs, an upper housing of the steering lock mechanism has a functional role that results in requirement of a specific material selection for it. Moreover, the functional role of the upper housing leads to critical design.

Accordingly, there exists a need to provide an electronic steering column lock mechanism that provides compact and simple design, less assembling cost, easy assembly and good manufacturability.

Object of the invention:

An object of the present invention is to provide an electronic steering column lock mechanism with compact and simple design that is easy to manufacture and assemble.

Summary of the invention:

Accordingly, the present invention provides an electronic steering column lock mechanism (hereinafter, “the mechanism”). The mechanism comprises a lower housing, a drive motor, a gear train, a locking arrangement, a gearbox cover and an upper housing.

The lower housing includes a location feature, a first pocket, a second pocket and a third pocket configured therein. The locating feature includes a stopper lug. The drive motor is positioned in the location feature of the lower housing. The drive motor includes a worm to capture an output thereof.

The gear train includes a worm gear, an idler gear and a lift gear. The worm gear is positioned in the first pocket of the lower housing. The worm gear includes a plurality of helical teeth and a plurality of spur type teeth configured thereon. The plurality of helical teeth engages with the worm of the drive motor and the plurality of spur type teeth engages with the idler gear that is further coupled to the lift gear.

The idler gear is positioned in the second pocket of the lower housing. The lift gear is positioned in the third pocket of the lower housing. Specifically, the lift gear is positioned on a friction shim to reduce the friction during gear rotation. The lift gear includes a slot configured thereon for accommodating a magnet molded with a magnet carrier.

The locking arrangement includes a cam, a lock bolt, a spring-lock bolt and a spring-cam. The locking arrangement translates up and down on a helical path provided at an inner diameter of the lift gear.

The gearbox cover is fitted on the lower housing using screws. The gearbox cover includes a plurality of tapped bosses, a featured surface and a slot. The plurality of tapped bosses facilitates fitting of a printed circuit board assembly therein. The slot is adapted to lock the friction shim. To dampen the vibrations created by the drive motor, a foam is placed between the drive motor and the gearbox cover.

The upper housing is fitted to the lower housing using a plurality of roll pins. The upper housing includes a rectangular pocket configured on an upper surface thereof. The rectangular pocket is used to bring out a connector of the printed circuit board assembly. The output of the drive motor captured by the worm drives the worm gear that further drives the idler gear that in turn drives the lift gear resulting in any one of an upward motion and a downward motion of the lock bolt thereby causing any one of a locking and an unlocking of a vehicle steering.

Brief description of the drawings:

The objects and advantages of the present invention will become apparent when the disclosure is read in conjunction with the following figures, wherein
Figure 1 shows a top view of a lower housing of an electronic steering column lock mechanism, in accordance with the present invention;

Figure 2 shows a perspective view of the lower housing of the electronic steering column lock mechanism, in accordance with the present invention;

Figure 3 shows a top view of the electronic steering column lock mechanism without an upper housing and a gearbox cover, in accordance with the present invention;
Figure 4 shows a perspective view of the electronic steering column lock mechanism without the upper housing and the gearbox cover, in accordance with the present invention;

Figure 5 shows a top view of the electronic steering column lock mechanism with the gearbox cover, in accordance with the present invention;

Figure 6 shows a perspective view of the gearbox cover, in accordance with the present invention;

Figure 7 shows a friction shim of the electronic steering column lock mechanism, in accordance with the present invention;

Figure 8 shows a perspective view of the electronic steering column lock mechanism with a printed circuit board assembly arranged thereon, in accordance with the present invention;

Figure 9 shows an outer view of the electronic steering column lock mechanism with the upper housing, in accordance with the present invention;

Figure 10 shows a cross-sectional view along B-B of figure 9, in accordance with the present invention;

Figure 11 shows an exploded view of a locking arrangement of the electronic steering column lock mechanism, in accordance with the present invention; and

Figure 12 shows a perspective view of an electronic steering column lock (ESCL), in accordance with the present invention.

Detailed description of the invention:

The foregoing objects of the present invention are accomplished and the problems and shortcomings associated with the prior art, techniques and approaches are overcome by the present invention as described below in the preferred embodiments.

The present invention provides an electronic steering column lock mechanism that has compact and simple design, less assembling cost, easy assembly and good manufacturability. A lower housing of the mechanism is provided with a feature for accommodating a drive motor, a gear train and a locking arrangement. The lower housing also provides facility to screw a gearbox cover thereto thereby constraining motions of all the covered parts. The drive motor is electronically actuated that drives the gear train and the motion is transferred to the locking arrangement to cause any one of a locking and unlocking of a vehicle steering.

The present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures. These reference numbers are shown in bracket in the following description and in table below.

Table:
Number Description Number Description
100 Electronic steering column lock mechanism 48 Magnet carrier
2 Stopper lug 54 Cam
4 Locating feature 58 Lock bolt
8 First pocket 62 Spring lock bolt
12 Second pocket 66 Spring cam
16 Third pocket 70 Locking arrangement
20 Lower housing 78 Slot of gearbox cover
30 Drive motor 74 Featured surface of gearbox cover
34 Worm gear 80 Gearbox cover
38 Idler gear 84 Foam
42 Lift gear 88 Roll Pins
44 Friction shim 90 Upper Housing
46 Magnet 95 PCBA
Referring to figures 1 to 12, an electronic steering column lock mechanism (100) (hereinafter referred as “the mechanism (100)”) in accordance with the present invention is shown. The mechanism (100) comprises a lower housing (20), a drive motor (30), a gear train (not numbered), a locking arrangement (70), a gearbox cover (80) and an upper housing (90).

The lower housing (20) includes a locating feature (4), a first pocket (8), a second pocket (12) and a third pocket (16) configured therein. The locating feature (4) includes a stopper lug (2). The locating feature (4) along with the stopper lug (2) accommodates the drive motor (30) there within. The drive motor (30) includes a worm (not shown) to capture an output thereof. In an embodiment, the drive motor (30) is electronically actuated.

The gear train includes a worm gear (34), an idler gear (38) and a lift gear (42). The worm gear (34) is positioned in the first pocket (8) of the lower housing (20). The output of the drive motor (30) captured by the worm drives the worm gear (34). In an embodiment, the worm gear (34) is compound type gear that includes a plurality of helical teeth (not numbers) and a plurality of spur type teeth (not numbered) configured thereon. The plurality of helical teeth engages with the worm of the drive motor (30) and the preceding plurality of spur type teeth engages with the idler gear (38) that is further coupled to the lift gear (42).

The idler gear (38) is positioned in the second pocket (12) of the lower housing (20). The lift gear (42) is positioned in the third pocket (16) of the lower housing (20). The lift gear (42) is placed on a friction shim (44) to reduce the friction during gear rotation. The lift gear (42) includes a slot (not numbered) configured thereon for accommodating a magnet (46) molded with a magnet carrier (48). Figure 10 shows a cut section of the mechanism (100). Thickness of the lower housing (20) in the functional area is more than the non-functional area to support the mechanism (100) and to give better strength to the mechanism (100).

As shown in figure 11, the locking arrangement (70) includes a cam (54), a lock bolt (58), a spring-lock bolt (62) and a spring-cam (66). The cam (54) is positioned on the lock bolt (58). The locking arrangement (60) is configured in the lower housing (20) to translate up and down on a helical path provided at an inner diameter of the lift gear (42). The third pocket (16) positions the lift gear (42) in a lower position that helps to reduce the overhung length of the lock bolt (58).

The gearbox cover (80) is fitted on the lower housing (20) using screws. The gearbox cover (80) blankets/covers the gear train, the drive motor (30) and the locking arrangement (70). The gearbox cover (80) includes a plurality of tapped bosses (not numbered), a featured surface (74) and a slot (78). The plurality of tapped bosses is configured on an upper surface of the gearbox cover (80). The plurality of tapped bosses facilitates fitting of a printed circuit board assembly (95) (hereinafter, PCBA “(95)”) therein. Specifically, the PCBA (95) is screwed on the gearbox cover (80). The PCBA (95) rests on the featured surface (74) that gives support to the PCBA (95). The featured surface (74) eliminates role of the upper housing (90) to accommodate PCBA (95) or any other child part. The slot (78) is adapted to lock the friction shim (44). To dampen the vibrations created by the drive motor (30), a foam (84) is placed between the drive motor (30) and gearbox cover (80). The gearbox cover (80), acting as a protection shield to the mechanism (100), restricts all degrees of freedom of whole mechanism and allows the gear train to transmit motion in only desired direction without disassembling from the lower housing (20).

The upper housing (90) is fitted to the lower housing (20) using a plurality of roll pins (88) that closes the mechanism (100). In an embodiment, the upper housing (90) and the lower housing (20) are configured with a plurality of linear holes (not numbered) for inserting the plurality of roll pins (88) therein. The upper housing (90) includes a rectangular pocket (not numbered) configured on an upper surface thereof. The rectangular pocket is used to bring out a connector (not numbered) of the PCBA (95). This connector connects the mechanism (100) to a whole electronic steering column lock (ESCL).

Again referring to figures 1-12, in an operation, the output of the drive motor (30) is captured by the worm that drives the worm gear (34). The worm gear (34) drives the idler gear (38) that in turn drives the lift gear (42) resulting in any one of an upward motion and a downward motion of the lock bolt (58) thereby causing any one of a locking and an unlocking of a vehicle steering. Position of the lift gear (42) is detected with the help of ‘Hall Effect’ which is created by the magnet (46) and sensed by Hall Effect sensors (not shown) positioned on the PCBA (95).

Advantages of the invention:
1. The unique lower housing (20) provides location for the drive motor (30) and the gear train, and locates the lift gear (42) in a lower position which results in less overhung length of the lock bolt (58) resulting in better stress distribution and more life of the lock bolt (58).
2. The lower housing (20) gives facility to screw the gearbox cover (80) thereto that constraints motions of all the covered parts and the plurality of tapped bosses of the gearbox cover (80) allows the PCBA (95) to be screwed thereon.
3. Presence of the idler gear (38) gives flexibility in meeting various torque and transmission requirements without much change in the mechanism (100).
4. Since there is no part fitted to the upper housing (90) and the upper housing (90) has no functional role when the mechanism (100) is considered, the user has freedom of choosing the material for the upper housing (90).
5. No functional role of the upper housing (90) also leads to compact and simple design, less assembling cost, easy assembly and good manufacturability.

The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, and to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but such omissions and substitutions are intended to cover the application or implementation without departing from the scope of the claims of the present invention. ,CLAIMS:We claim:

1. An electronic steering column lock mechanism (100) comprising:
a lower housing (20) having a location feature (4), a first pocket (8), a second pocket (12) and a third pocket (16) configured therein, the location feature (4) having a stopper lug (2);
a drive motor (30) positioned in the location feature (4) of the lower housing (20), the drive motor (30) having a worm to capture an output thereof;
a gear train having,
a worm gear (34) positioned in the first pocket (8) of the lower housing (20), the worm gear (34) having a plurality of helical teeth and a plurality of spur type teeth configured thereon,
an idler gear (38) positioned in the second pocket (12) of the lower housing (20), and
a lift gear (42) positioned in the third pocket (16) of the lower housing (20), the lift gear (42) being positioned on a friction shim (44) to reduce the friction during gear rotation;
a locking arrangement (70) having a cam (54), a lock bolt (58), a spring-lock bolt (62) and a spring-cam (66), the locking arrangement (70) capable of translating up and down on a helical path provided at an inner diameter of the lift gear (42);
a gearbox cover (80) fitted on the lower housing (20) using screws, the gearbox cover (80) having a plurality of tapped bosses, a featured surface (74) and a slot (78), the plurality of tapped bosses facilitating fitting of a printed circuit board assembly (95) therein, the slot (78) adapted to lock the friction shim (44); and
an upper housing (90) fitted to the lower housing (20) using a plurality of roll pins (88),
wherein, the output of the drive motor (30) captured by the worm drives the worm gear (34) that further drives the idler gear (38) that in turn drives the lift gear (42) resulting in any one of an upward motion and a downward motion of the lock bolt (58) thereby causing any one of a locking and an unlocking of a vehicle steering.

2. The electronic steering column lock mechanism (100) as claimed in claim 1, wherein the plurality of helical teeth of the worm gear (34) engages with the worm of the drive motor (30) and the plurality of spur type teeth engages with the idler gear (38) that is further coupled to the lift gear (42).

3. The electronic steering column lock mechanism (100) as claimed in claim 1, wherein to dampen the vibrations created by the drive motor (30), a foam (84) is placed between the drive motor (30) and the gearbox cover (80).

4. The electronic steering column lock mechanism (100) as claimed in claim 1, wherein the lift gear (42) includes a slot configured thereon for accommodating a magnet (46) molded with a magnet carrier (48).

5. The electronic steering column lock mechanism (100) as claimed in claim 1, wherein the upper housing (90) includes a rectangular pocket configured on an upper surface thereof, the rectangular pocket is used to bring out a connector of the printed circuit board assembly (95).

Dated this 01st day of November, 2019

Prafulla Wange
(Agent for applicant)
IN/PA-2058