STEERING LOCK APPARATUS

Background of the Invention

Field of the Invention

[0001]

The present invention relates to a steering lock apparatus for locking a steering wheel of a motor vehicle or the like for the purpose of an antitheft

Description of the Related art

[0002]

The steering lock apparatus is arranged in a steering shaft rotating in accordance with a steering operation of a motor vehicle. The steering lock apparatus is structured such that a lock bolt is installed into a housing, and the lock bolt is withdrawn into the housing in a case that a driver starts an engine, thereby releasing (unlocking) a lock with respect to the steering shaft by the lock bolt. On the contrary, when the engine is stopped, the lock bolt is moved forward from the housing so as to come to a state capable of engaging with the steering shaft. If the lock bolt coincides with an engagement groove of the steering shaft in a radial direction under this state, the steering shaft is locked by an engagement thereof.

[0003]

In a steering lock apparatus described in Japanese Unexamined Patent Publication No. 2008-100643, a driving force of a motor is transmitted to a shaft member having a worm wheel portion so as to rotate. Further, if the shaft member rotates, a cam member moves straight in a vertical direction in an axial direction of the shaft member, or rotates integrally with the shaft member. Further, if the cam member is rotated in an unlock actuating direction by a forward rotating drive of the motor, a lock bolt moves forward (protrudes) via a slider, and comes to a state capable of engaging with a steering shaft. Further, if the cam member is rotated in a lock actuating direction by driving the motor to reverse rotate, the lock bolt moves backward (withdraws) via the slider, and an engagement with the steering shaft is released.

[0004]

However, in the steering lock apparatus described in Japanese Unexamined Patent Publication No. 2008-100643, the cam member for actuating the lock bolt is arranged in the shaftmember, and the shaft member is supported between a housing and a lid closing an opening portion of the housing. Further, while the lock bolt is made of a metal, the shaft member is made of a resin for achieving a weight saving of a vehicle. Accordingly, the shaft member has a problem that both end portions supported by the housing and the lid tend to wear. Moreover, the shaft member is possibly damaged if an overload is applied at a time of the lock actuation.

[0006]

An object of the present invention is to provide a steering lock apparatus which can prevent a shaft member exposed to a driving force from wearing and being damaged, and can improve a durability.

[0007]

In order to achieve the above object, a steering lock apparatus according to the present invention includes:

a housing having one end opened and another end closed, provided with an axial hole portion in a wall portion on the closed other end, and having an insertion hole formed in a predetermined wall portion;

a lid attached to close an opening portion of the housing and provided with a support portion at a position corresponding to the axial hole portion;

an actuator arranged in the housing or the lid, and energized to drive so as to forward rotate or reverse rotate;

a transmission mechanism having a shaft member with one end supported to the support portion of the lid and with another end supported within the axial hole portion of the housing, and the other end being provided with a stopper portion coming into contact with a periphery of the axial hole portion, and the transmission mechanism receiving and transmitting a driving force of the actuator; and

a lock member receiving the driving force of the actuator via the transmission mechanism, and moving between a lock position in which the lock member partly protrudes from the insertion hole of the housing and is capable of engaging with a movable member working with an operation of a steering wheel, and an unlock position in which the lock member retracts into the insertion hole of the housing so as to release engagement with the movable member.

[0008]

In the steering lock apparatus in accordance with the present invention, the lid is provided with the support portion supporting one end of the shaft member, the housing is provided with the axial hole portion supporting the other end of the shaft member, and the shaft member is provided with the stopper portion coming into contact with the periphery of the axial hole portion. Accordingly, a contact area between the end portion of the shaft member and the housing becomes large, so that it is possible to suppress the wear of the leading end portion of the shaft member.
[0009]

In the steering lock apparatus, preferably, the transmission mechanism further includes a cam member,

wherein at a time, of releasing the engagement of the lock member with the movable member, the cam member integrally rotates with the shaft member in a state in which substantially no

resistance exists between the movable member and the lock member and moves in an axial direction with respect to the shaft member in a state in which a resistance having a predetermined value or more exists between the movable member and the lock member, and

wherein at a time of engaging the lock member with the movable member, the cam member comes into contact with the stopper portion of the shaft member to stop.
Specifically, the cam member is formed substantially in a cylindrical shape to pass the shaft member therethrough and engage the lock member with an outer peripheral portion thereof, a thread ridge is provided in one of the shaft member and the cam member, and a thread groove is formed in the other member, and the cam member is integrally rotatable and movable in an axial direction with respect to the shaft member by engagement between the thread ridge and the thread groove.

In accordance with this structure, even if the cam member moves in the axial direction with respect to the shaft member by the biasing force of the biasing member biasing the lockmember in the protruding direction in a case that the thread ridge or the thread groove wears and the engagement between the shaft member and the cam member cannot be maintained, the cam member stops by coming into contact with the stopper portion. Therefore, it is possible to prevent the cam member from separating from the shaft member.

Preferably, the transmission mechanism further includes a worm wheel provided as an independent member which is assembled in an end portion of the shaft member on an inverse side to the stopper portion after assembling the shaft member and the cam member so as to be engaged with each other, and wherein the worm wheel receives the driving force of the actuator to transmit to the shaft member. In accordance with this structure, it is possible to easily assemble the shaft member and the cam member constructing the transmission mechanism.

[0011]

Further, a slidable contact portion coming into contact with the lid is preferably provided in a bottom surface of the worm wheel. As in the case that the driving force of the actuator is received by the worm wheel, the force acts on a direction 3 inclined to the axial direction in addition to the force in the rotating direction. Accordingly, it is possible to improve a stability in the axial direction of the shaft member by providing in the bottom surface of the worm wheel the slidable contact portion coming into contact with the lid. Therefore, it is 5 possible to reduce an overload to the shaft member at a time of driving.

[0012]

In the steering lock apparatus in accordance with the present invention, since the shaft member is provided with the stopper portion coming into contact with the periphery of the axial hole portion of the housing, it is possible to increase the contact area between the end portion of the shaft member and the housing. As a result, it is possible to suppress the wear of the leading end portion of the shaft member. Further, since the slidable contact portion coming into contact with the lid is provided in the worm wheel arranged in the end portion in the opposite side to the stopper portion of the shaft member, it is possible to improve a rotation stability of the shaft member at a time of driving together with the stopper portion, and it is possible to reduce the wear and the overload of the shaft member. As a result, it is possible to improve the durability of the shaft member.

Brief Description of the Drawings

[0013]

Fig. 1 is a cross sectional view showing a steering lock apparatus in accordance with an embodiment of the present invention;

Fig. 2 is a perspective view showing a state in which a housing is detached from a lid;

Fig. 3 is an exploded perspective view of a lock unit;

Fig. 4 is an exploded cross sectional view showing a worm wheel, a shaft member and a cam member constructing a transmission mechanism;

Fig. 5 is a process chart showing an unlock actuation in a state in which no resistance exists;

Fig. 6 is a process chart Showing an unlock actuation in a state in which a resistance exists;

Fig. 7 is a process chart showing a lock actuation in a state in which an engagement groove of a steering shaft coincides with a lock bolt; and

Fig. 8 is a process chart showing a lock actuation in a state in which the engagement groove of the steering shaft does not coincide with the lock bolt.

Detailed Description of the Preferred Embodiments

[0014]
A description will be given below of an embodiment in accordance with the present invention with reference to the accompanying drawings.

[0015]
Fig. 1 shows a steering lock apparatus in an embodiment in accordance with the present invention. The steering lock apparatus is structured such as to rotatably release (unlock) an engagement and unrotatably engage (lock) a steering shaft 1 serving as a movable member working with an operation of a steering wheel (not shown) by a control signal from a controller (a host ECU) mounted to a vehicle and an electric power from abattery. In the following description, terms "upper", "lower", "left", "right", "front", "rear", "vertical" and "lateral" are used as a matter of convenience, however, they do not limit the construction of the present invention by any means.
[0016]
As shown in Figs. 1 and 2, the steering lock apparatus is provided with a casing constructed by a housing 10 and a lid 14 so as to be integrally installed to an outer peripheral portion of the steering shaft 1. In this case, engagement grooves 2 extending along an axial direction are provided in the steering shaft 1 so as to be spaced from each other at a predetermined distance in a peripheral direction. Further, the steering shaft lis cove red with a cylindrical steering column 3 in its periphery, and a lock bolt 46 to be mentioned below can move forward and backward from an opening portion of the steering column 3.

[0017]
The housing 10 is formed as an integrally molded component made of a metal such as zinc, and is formed in a box shape with a lower end opened and an upper end closed. The housing 10 is provided with an approximately semi cylindrical shaft installation portion 11 in an upper closed wall portion 10a positioned in an opposite side to the opening portion. Further, the closed wall portion 10a is provided with a lock bolt insertion hole 12 formed in an approximately rectangular shape so as to pass through an inner portion, in such a manner as to be positioned approximately in a center portion of the shaft installation portion 11. Further, an axial hole portion 13 supporting a shaft member 27 is provided in an inner surface side of the closed wall portion 10a of the housing 10 in such a manner as to be positioned beside a lock bolt insertion hole 12. Further, the closed wall portion 10a of the housing 10 is provided with a hook portion (not shown) locking an upper end of an unlock spring 44.
[0018]
The lid 14 is attached by screwing in such a manner as to close the opening portion of the housing 10, and is formed as an integrally molded component made of a metal such as zinc in the same manner as the housing 10. The lid 14 is provided in a rising manner with a plurality of support walls 15 supporting a switch case 17 and a lock unit 18 to be mentioned below so as to integrate (modularize) , as shown in Figs. 2 and 3. Among them, a support wall 15a is formed at a position corresponding to an axial direction with respect to the axial hole 13 of the housing 10 in such a manner as to form an approximately circular accommodation space. The accommodation space rotatably accommodates a worm gear 21 and a worm wheel 22 to be mentioned below. Further, the lid 14 is provided with a shaft-shaped support portion 16 corresponding to the axial hole portion 13 of the housing 10 in such a manner as to be positioned in a center of the accommodation space.
[0019]
A switch case 17 and a lock unit 18 are arranged in an interior space of the housing 10 and the lid 14. Among them, the switch case 17 accommodates a detection switch detecting in which one of actuation states of an advanced state (a lock state) and an withdrawn state (an unlock state) a lock bolt 46 constructing the lock unit 18 is, and a control circuit board controlling so as to energize an electric motor 19 in correspondence to a control signal from a controller of the vehicle. Further, the lock unit 18 is roughly constructed by the electric motor 19, the worm gear 21, the worm wheel 22, a shaft member 27, a cam member 35, a slider 38 and a lock bolt 46. The worm gear 21, the worm wheel 22, the shaft member 27 and the cam member 35 construct a transmission mechanism receiving a driving force of the electric motor 19 so as to transmit to the slider 38. Further, the slider 38 and the lock bolt 46 construct a lock member receiving the driving force of the electric motor 19 via the transmission mechanism so as to lock and unlock the steering shaft 1.

[0020]
The electric motor 19 is an actuator driving so as to forward rotate and driving so as to reverse rotate in accordance with the energizing, and is fixed onto the lid 14 by the support wall 15. The electric motor 19 is structured such that a pair of connection portions 20a and 20b are connected to a terminal portion (not shown) provided in the switch case 17, and an electric power is fed from an in-vehicle battery (not shown). A positive pole current is applied to the connection portion 20a and a negative pole current is applied to the connection portion 20b, whereby the electric motor 19 drives so as to forward rotate, and the negative pole current is applied to the connection portion 20a and the positive pole current is applied to the connection portion 20b, whereby it drives so as to reverse rotate. Further, these energizing states are switched by the switch case 17 in accordance with a control signal input to the switch case 17.
[0021]
The worm gear 21 is made of a metal, and is firmly attached to an output shaft of the electric motor 19. The worm gear 21 is arranged in such a manner as to be positioned within the support wall 15a of the lid 14 by arranging the electric motor 19 in the lid 14. [0022]

The worm wheel 22 is made of a resin, and is formed in a disc shape provided with a gear (a diagonal tooth) extending while being inclined diagonally to an outer peripheral portion. The worm wheel 22 is provided in a center with a fixing hole 23 fixing a lower end of the shaft member 27. The fixing hole 23 is formed in a non-circular shape, and passes through along an axial direction. Further, an inner portion of the fixing hole 23 is provided with a guide groove 24a regulating the fixing position of the shaft member 27, and an engagement protruding portion 24b positioning and fixing the shaft member 27, as shown in Fig. 4. Further, the worm wheel 22 is rotatably pivoted within the support wall 15a by arranging the shaft member 27 so as to be inserted to the support portion 16 of the lid 14 in a state of being arranged in the shaft member 27. In a state in which the worm wheel 22 is arranged, the worm gear 21 extends in a tangential direction in an outer peripheral portion thereof, and the both gears engage with each other. Accordingly, a rotating power of the electric motor 19 is transmitted to the worm wheel 22 via the worm gear 21, and the worm wheel 22 is rotated around an axial core by the driving force. In the present embodiment, as shown in Fig. 1, a bottom surface of the worm wheel 22 is provided with an approximately circular slidable contact portion 25 coming into contact with an upper surface of the lid 14 in such a manner as to bulge in an axial direction. Further, a lower end portion of the shaft member 27 is structured such as to stabilize the rotations of the shaft member 27 and the worm wheel 22 at a time of driving together with a stopper portion 33 of the shaft member 27 to be mentioned below, by being attached in such a manner as to be approximately flush with the bottom surface of the worm wheel 22 . The worm wheel 22 is provided with a regulation portion 26 in an outer peripheral portion of the fixing hole 23 so as to protrude upward.
[0023]
The shaft member 27 is made of a resin, and is formed in
a columnar shape extending upward along an axial direction of the worm wheel 22, by inserting its lower end to the fixing hole 23 of the worm wheel 22 so as to fix, as shown in Figs. 3 and 4. A lower end of the shaft member 27 is provided with a non-circular fixing portion 28 having a chamfer portion. The fixing portion 28 is provided with a guide convex portion 29 corresponding to the guide groove 24a of the worm wheel 22, and an engagement hole 30 corresponding to the engagement protrusion portion 24b. Further, the shaft member 27 is provided with an installation hole 31 capable of inserting thereto the support portion 16 of the lid 14 in such a manner as to extend upward along an axial direction from a lower end surface. Further, an upper end of the shaft member 27 constructs a shaft portion 32 arranged within the axial hole portion 13 of the housing 10. Accordingly, the shaft member 27 is arranged in such a manner that the lower end is supported to the support portion 16 of the lid 14 and the upper end is supported within the axial hole portionl3of the housing 10. Further, in the present embodiment, an end portion positioned close to the shaft portion 32 is provided with the stopper portion 33 protruding outward in a radial direction so as to form a disc shape. The stopper portion 33 is structured such that a leading end of the shaft portion 32 does not come into contact with a bottom (an upper end) of the axial hole portion 13 by being provided at a position coming into contact with the periphery of the axial hole portion 13
in an assembled state in which the shaft portion 32 is inserted to the axial hole portion 13 (refer to Fig. 1) . Further, the shaft member 27 is provided with a thread ridge 34 serving as a male screw protruding so as to form a spiral shape, in an outer peripheral portion positioned in a lower portion of the stopper portion 33.
[0024]
The cam member is made of a resin, and converts the rotation by the driving force of the electric motor 19 into a linear motion in an axial direction of the slider 38. The cam member 35 is formed in an approximately cylindrical shape having a through hole passing through in the axial direction, and an inner peripheral surface of the through hole is provided with a thread groove 36 serving as a female screw in correspondence to the thread ridge 34 of the shat member 27. Further, an outer peripheral portion of the cam member 35 is provided with a cam groove 37 engaging a slider 38 therewith in such a manner as to spirally extend over about 360 degrees. The cam member 35 is structured such that the shaft member 27 is passed through in a state of engaging from a lower end portion in an inverse side to the stopper portion 33, and the worm wheel 22 is thereafter assembled to the shaft member 27. Accordingly, the cam member 35 is integrally rotatable and movable in the axial direction with respect to the shaft member 27, if the shaft member 27 rotates in accordance with the rotation of the worm wheel 22. In other
words, the cam member 35 linearly moves in the axial direction with respect to the shaft member 27, or integrally rotates together with the worm wheel 22. Further, the upward movement with respect to the shaft member 27 stops by coming into contact with the stopper portion 33.
[0025]
The slider 38 is made of a metal, and moves forward and backward the lock bolt 46 between the lock position and the unlock position by receiving the driving force of the electric motor 19 via the cam member 35. The slider 38 is supported by the support wall 15 of the lid 14 so as to be slidable in the vertical direction. Further, the slider 38 is provided with an engagement and insertion portion 39 inserted to and engaged with the cam groove 37 of the cam member 35 while protruding in a lateral direction. Accordingly, if the cam member 35 moves up and down with respect to the shaft member 27, the slider 38 moves up and down in parallel to the shaft member 27 together with the cam member 35. Further, if the cam member 35 rotates together with the shaft member 27, the engagement and insertion portion 39 relatively moves along the cam groove 37 of the cam member 35, whereby the slider 38 moves up and down. Further, the slider 38 is provided in a center portion thereof with an accommodation portion 40 which is open in an upper side and one lateral side, and is closed in a lower side. The closed portion of the accommodation portion 40 is provided with a first spring receiving portion 41 formed in a circular cone shape. Further, the lock bolt 46 is arranged in the accommodation portion 40 via a lock spring 42. Moreover, a second spring receiving portion 43 in a circular cone shape is provided in the slider 38 on the same side as the engagement and insertion portion 39. A lower end of a coil-shaped unlock spring 44 is fitted and locked to the second spring receiving portion 43. A hook 44a at an upper end of the unlock spring 44 is hooked to an inner surface of the housing 10. Accordingly, the unlock spring 44 presses and biases the slider 38 in an unlocking direction in an assembly finished state. Further, numeral 45 denotes a switch actuation portion 45 capable of detecting whether the slider 38 actuates to the lock position or actuates to the unlock position, by operating the switch receiving portion of the switch case 17.
[0026]
The lock bolt 46 is made of a rectangular cast metal, and is provided with an engagement portion 47 formed in a trapezoidal shape in a side view at a leading end in a forward moving direction. Further, a long hole 48 extending in a vertical direction (a forward and backward moving direction) and passing through in a thickness direction is formed in the lock bolt 46 somewhat closer to a lower side than the center in the vertical direction. Further, a spring accommodating concave portion 4 9 is formed in a lower end portion of the lock bolt 46. The lock bolt 46 is assembled in the slider 38 by passing through the long hole 48 by a pin 50 in a state of being arranged in the accommodation portion 40 of the slider 38. The lock bolt 46 assembled as mentioned above moves up and down together with the slider 38. In a state in which the engagement portion 47 of the lock bolt 4 6 does not coincide with the engagement groove 2 and cannot move forward, the pin 50 can move in the vertical direction within the long hole 48, whereby the lock bolt 46 relatively moves in the vertical direction with respect to the slider 38. If the engagement portion 47 coincides with the engagement groove 2, the lock bolt 46 protrudes by the biasing force of the lock spring 42 .
[0027]
The lock bolt 46 is subjected to the driving force of the electric motor 19 via the transmission mechanism constructed by the cam member 35, the shaft member 27, the worm wheel 22 and the worm gear 21. Further, it moves between the lock position at which the engagement portion 47 protrudes from the lock bolt insertion hole 12 of the housing 10 so as to be capable of engaging with the engagement groove 2 of the steering shaft 1, and the unlock position at which it is withdrawn into the insertion hole of the housing 10 so as to release the engagement with the engagement groove 2. Further, the transmission mechanism is structured such that the cam member 35 comes into contact with the stopper portion 33 of the shaft member 27 so as to stop, at a time of engaging the lock bolt 46 with the steering shaft 1. Further, when the engagement of the lock bolt 46 is released with respect to the steering shaft 1, the cam member 35 rotates integrally with the shaft member 27 in a state in which a resistance hardly exists between them. On the other hand, in a state in which resistance of a predetermined value or more is provided between the steering shaft 1 and the lock bolt 46, the cam member 35 moves in the axial direction with respect to the shaft member 27. [0028]
Next, an unlock actuation and a lock actuation of the steering lock apparatus in accordance with the present embodiment will be described.
[29]
First of all, when the engine start and the operation of the motor vehicle are inhibited, the lock bolt 46 is at the lock position. In this state, since the engagement portion 47 of the lock bolt 46 engages with the engagement groove 2 of the steering shaft 1, whereby the steering shaft 1 is locked. The state in which the engine start and the operation are inhibited indicates, for example, a state in which a user having a registered electronic key neither is on board nor exists near the motor vehicle.
[30]
Fig. 5 shows in stages an unlock actuation in a normal state in which a great pulling force is not necessary in the lock bolt 46 (no resistance exists) at a time of moving backward the lock bolt 46 from the engagement groove 2 of the steering shaft 1 so as to release the engagement.
[31]
In a state A, the lock bolt 46 is at the lock position, the engagement portion 47 at its leading end engages with the engagement groove 2 of the steering shaft 1. At this time, in a case that the side surface of the engagement groove 2 does not come into pressure contact with the side surface of the engagement portion 47, a great pulling force is not necessary for releasing the engagement of the lock bolt 46 from the steering shaft 1. Further, when the lock bolt 46 is at the lock position, the engagement and insertion portion 39 of the slider 38 is positioned at an upper end of the cam groove 37 of the cam member 35.
[32]
If the user having the registered electronic key gets on the motor vehicle and pushes the engine actuation switch in this state A, the controller of the vehicle outputs a start command, and if the control signal is input to the control circuit board of the switch case 17, the electric motor 19 is controlled to be energized and is driven so as to forward rotate. Accordingly, the power of the electric motor 19 is transmitted via the worm gear 21, and the worm wheel 22 is rotated in a counterclockwise direction in an upward view.
At this time, in a normal state in which no resistance exists, the pulling force of the lock bolt 46 is comparatively weak. Accordingly, since a friction force between the shaft member 27 of the worm wheel 22 and the cam member 35 is larger than a friction force between the engagement and insertion portion 39 of the slider 38 and the side surface of the cam groove 37 of the cam member 35, the cam member 35 rotates integrally with the worm wheel 22 . Accordingly, if the cam member 35 starts rotating together with the worm wheel 22, the engagement and insertion portion 39 of the slider 38 moves along the cam groove 37 of the cam member 35, and the lock bolt 46 linearly moves downward in the unlock direction from the lock direction, as shown in a state B. Accordingly, the engagement portion 47 of the lock bolt 46 gets out of the engagement groove 2 of the steering shaft 1 so as to be release its engagement (unlocked).
[34]
If the cam member 35 further rotates, the lock bolt 46 further moves downward into a state C while the engagement and insertion portion 39 of the slider 38 moves along the cam groove 37, and the engagement and insertion portion 39 comes into contact with the lower end of the cam groove 37 . Accordingly, the further rotation of the cam member 35 is regulated. At this time, the engagement portion 47 of the lock bolt 46 has already got out of the engagement groove 2 of the steering shaft 1. However,
the lock bolt 46 has not reached the unlock position yet.
[35]
Accordingly, the electric motor 19 continuously keeps the forward rotating drive even after reaching the state C. Therefore, the worm wheel 22 also keeps the rotation. At this time, since the rotation of the cam member 35 has already regulated, the cam member 35 moves downward in the axial direction with respect to the shaft member 27 by the screw drive while keeping the state in which the engagement and insertion portion 39 of the slider 38 is in contact with the end portion of the cam groove 37. The slider 38 and the lock bolt 46 linearly move downward in accordance therewith, and reaches the unlock position shown in a state D.
[36]
At this time, the further downward movement of the cam member 35 is regulated its by the lower surface coming into contact with the regulation portion 26 of the worm wheel 22. At this time, the detection switch of the switch case 17 is actuated by the switch actuation portion 45 of the slider 38, the control circuit board of the switch case 17 detects the fact that the lock bolt 46 reaches the unlock position, and the drive of the electric motor 19 is stopped. In the unlock actuation mentioned above, the biasing force of the unlock spring 44 pressing the slider 38 becomes maximum in the state A and becomes minimum in the state D. Accordingly, the unlock spring 44 functions
to assist the pulling force of the lock bolt 46.
[37]
Fig. 6 shows in stages an unlock actuation at a dry steering time when a great pulling force is required to the lock bolt 46 (having a resistance equal to or more than a predetermined value) , at a time of moving backward the lock bolt 46 from the engagement groove 2 of the steering shaft 1 so as to release the engagement. In this case, "dry steering time" indicates
a state in which the engagement portion 47 of the lock bolt 46
%
is fitted to the engagement groove 2 of the steering shaft 1 and a torque is applied by rotating the steering shaft 1 whereby the side surface of the engagement groove 2 strongly comes into pressure contact with the side surface of the engagement portion 47. In this state, a great pulling force equal to or more than a predetermined amount is required to pull the lock bolt 46, ' and a torque or a load (a resistance) acting on the lock bolt 46 at this time is called as "dry steering torque".
[38]
In the state A, in the same manner as Fig. 5, the lock bolt 46 is at the lock position, and the upper end of the cam groove 37 of the cam member 35 is in contact with the engagement and insertion portion 39 of the slider 38. From this state, the electric motor 19 starts forward rotating drive in such a manner as to achieve the unlock actuation in the same manner as mentioned above. At this time, since the dry steering torque
acts on the lock bolt 46; the pulling force becomes larger in comparison with the normal state. Accordingly, since the friction force between the engagement and insertion portion 39 of the slider 38 and the side surface of the cam groove 37 of the cam member 35 is larger than the friction force between the shaft member 27 of the worm wheel 22 and the cam member 35, the shaft member 27 rotates in the counterclockwise direction in an upward view with respect to the cam member 35 without the cam member 35 rotating together with the shaft member 27. Therefore, the cam member 35 linearly moves downward by the screw drive without rotating. The lock bolt 46 linearly moves downward in accordance therewith, and moves downward until the lower surface of the cam member 35 comes into contact with the regulation portion 26 so as to come to a state G. At this time, the engagement portion 47 of the lock bolt 46 gets out of the engagement groove 2 of the steering lock bolt so as to come to a state of being released from its engagement (being unlocked). [0039]
In a case that the dry steering torque is applied as mentioned above, since the lock bolt 46 is moved downward by the screw drive, the great pulling force can be obtained while the actuation speed is slow in comparison with the actuation by the cam groove 37 as in the case of Fig. 5, and it is possible to securely pull the lock bolt 46 to which the dry steering torque is applied.
The force required to move the lock bolt 46 after the engagement with the steering shaft 1 is released becomes comparatively small. Accordingly, since the friction force between the shaft member 27 of the worm wheel 22 and the cam member 35 is larger than the friction force between the engagement and insertion portion 39 of the slider 38 and the cam groove 37 of the cam member 35 after the state G, the cam member 35 rotates integrally with the worm wheel 22. Therefore, if the cam member 35 rotates together with the worm wheel 22, the engagement and insertion portion 39 of the slider 38 separates from the upper end of the cam groove 37 of the cam member 35 so as to move along the cam groove 37, and the lock bolt 4 6 linearly moves further downward in accordance therewith as shown in a state H. Further, when the engagement and insertion portion 39 of the slider 38 comes into contact with the lower end of the cam groove 37, the lock bolt 46 reaches the unlock position shown in the state D, and the actuation of the electric motor 19 is stopped at the same time.

As mentioned above, in accordance with the steering lock apparatus of the present embodiment, since the cam member 35 which can rotate and linearly move with respect to the shaft member 27 is provided as the member transmitting the power to the lock bolt 46, two methods can be employed for driving the lock bolt 46. More specifically, at a time of the linear movement of the cam member 35 with respect to the shaft member 27, the great pulling force can be obtained while the actuating speed of the lock bolt 46 is slow. On the other hand, at a time of the rotation of the cam member 35 with respect to the shaft member 27, it is possible to increase the actuating speed while the pulling force of the lock bolt 46 is small. Accordingly, it is possible to give preference to a quick movement of the lock bolt 46 by the rotation of the cam groove 37 of the cam member 35 in the normal state in which any particular load is not applied to the lock bolt 46, and it is possible to give preference to the pulling of the lock bolt 46 with the great force by the linear movement of the cam member 35 in the state in which the dry steering torque is applied.
[42]
Fig. 7 shows in stages the lock actuation in the normal state in which the engagement portion 47 of the lock bolt 4 6 coincides with the engagement groove 2 at a time of moving forward the lock bolt 4 6 so as to engage with the engagement groove 2 of the steering shaft 1. In this case, the state D indicates the unlock position in the same manner as in Figs. 5 and 6.
[43]
At a time of detecting the fact that the user having the registered electronic key is away from the motor vehicle by a predetermined distance or more after stopping the engine or after stopping the engine and closing the vehicle door, the controller of the vehicle outputs a lock command to the steering lock apparatus. If this control signal is received, the electric motor 19 is driven so as to reverse rotate. Accordingly, the driving force of the electric motor 19 is transmitted via the worm gear 21, and the worm wheel 22 rotates in the clockwise direction in an upward view.
[44]
At this time, the pressing force for linearly moving the lock bolt 46 upward may be small. Accordingly, the friction force between the shaft member 27 of the worm wheel 22 and the cam member 35 is larger than the friction force between the engagement and insertion portion 39 of the slider 38 and the side surface of the cam groove 37 of the cam member 35, so that the cam member 35 rotates integrally with the worm wheel 22. Therefore, when the cam member 35 starts rotating in the clockwise direction in the upward view together with the worm wheel 22, the engagement and insertion portion 39 of the slider 38 separates from the lower end of the cam groove 37 of the cam member 35 so as to move along the cam groove 37, and the lock bolt 4 6 linearly moves upward from the unlock position toward the lock direction in accordance therewith as shown in a state E .
[45]
Thereafter, the lock bolt 46 linearly moves upward in accordance with the further rotation of the cam member 35.
However, the rotation of the cam member 35 is regulated at a time when the engagement and insertion portion 39 of the slider 38 comes into a state F in which it comes into contact with the upper end of the cam groove 37. Since the reverse rotating drive of the electric motor 19 is still continued, the worm wheel 22 and the shaft member 27 also keep rotating. Accordingly, the cam member 35 linearly moves upward with respect to the shaft member 27 by the screw drive without rotating. In accordance therewith, the lock bolt 46 also linearly moves upward so as to reach the lock position in the state A. Further, the cam member 35 comes into contact with the stopper portion 33 of the shaft member 27. At this time, the detection switch of the switch case 17 is actuated by the switch actuation portion 45 of the slider 38, the control circuit board of the switch case 17 detects the fact that the lock bolt 46 reaches the lock position, and the drive of the electric motor 19 is stopped. Accordingly, the engagement portion 47 of the lock bolt 46 is fitted into the engagement groove 2 of the steering shaft 1, and the steering shaft 1 (the steering wheel) is locked. [0046]
Fig. 8 shows a lock actuation in a case that the engagement groove 2 of the steering shaft 1 does not coincide with the engagement portion 47 of the lock bolt 46 at a time of the lock actuation. In this case, the state D and the state E until the engagement portion 47 of the lock bolt 46 comes into contact with the outer peripheral surface of the steering shaft 1 are the same as those of the normal lock actuation.
[47]
More specifically, when the engagement and insertion portion 39 of the slider 38 comes into the state F in which it comes into contact with the upper end of the cam groove 37 by the forward rotating drive of the electric motor 19, the rotation of the cam member 35 is regulated. Since the reverse rotation of the electric motor 19 is continued thereafter, the worm wheel 22 and the shaft member 27 keep on rotating. Further, when the lock bolt 46 linearly moved upward further from the state F, the leading end of the engagement portion 47 of the lock bolt 46 comes into contact with the outer peripheral surface of the steering shaft 1. Therefore, the further upward movement is regulated. However, since the reverse rotating drive of the electric motor 19 is continued, the cam member 35 moves upward with respect to the shaft member 27 by the screw drive, and the slider 38 moves upward in accordance therewith.
[48]
At this time, the lock bolt 46 in accordance with the present embodiment is assembled to the slider 38 so as to be relatively movable by the long hole 48 and the pin 50. Accordingly, the lock bolt 4 6 does not move by the contact with the outer peripheral surface of the steering shaft 1, and only the slider 38 moves. Therefore, the lock spring 42 arranged between the slider 38 and the lock bolt 46 is elastically contracted. Further, if the cam member 35 comes into contact with the stopper portion 33 of the shaft member 27, the upward movement of the slider 38 is stopped because the drive of the electronic motor 19 is stopped. As a result, the lock bolt 46 comes into a state A' in which it is strongly biased into the lock direction by the lock spring 42.
[49]
In this state A' , since the engagement portion 47 of the lock bolt 46 does not engage with the engagement groove 2 of the steering shaft 1, it is possible to rotationally operate the steering shaft 1 (the steering wheel). However, if the engagement groove 2 of the steering shaft 1 coincides with the engagement portion 47 of the lock bolt 46 in the radial direction by the rotating operation, the lock bolt 46 is moved upward by the biasing force of the lock spring 42, and the engagement portion 47 is fitted to the engagement groove 2, thereby coming into the lock state shown as in the state A.
[50]
As mentioned above, if the electric motor 19 is driven so as to rotate forward or is driven so as to rotate reverse in accordance with the control signal of the controller, the steering lock apparatus of the present invention rotates the shaft member 27 constructing the transmission mechanism, and can achieve the unlock actuation or the lock actuation of the
slider 38 and the lock bolt 46 serving as the lock members via
the cam member 35.
[0051]
Further, the shaft member 27 in accordance with the present embodiment is structured such that the lower end thereof is supported to the support portion 16 of the lid 14 and the upper end thereof is supported to the axial hole portion 13 of the housing 10, as well as the upper end thereof is provided with the stopper portion 33 coming into contact with the periphery of the axial hole portion 13. Accordingly, the contact area between the end portion (the shaft portion 32) of the shaft member 27 and the housing 10 becomes large. As a result, since the load applied to the shaft portion 32 in accordance with the rotation of the shaft member 27 can be reduced, it is possible to suppress the abrasion. Further, in the present embodiment, since the slidable contact portion 25 coming into contact with the lid 14 is provided in the bottom surface of the worm wheel 22 arranged at the lower end of the shaft member 27, it is possible to further reduce the abrasion of the shaft member 27 and the overload applied to the shaft member 27. Specifically, since the structure is made such that the worm wheel 22 receives the driving force of the drive motor from the worm gear 21, the force is also applied to the worm wheel 22 in the direction inclined in the axial direction, in addition to the force in the rotating direction. However, the present embodiment has the structure in which the force is suppressed by the stopper portion 33 having a large-diameter provided in the upper end portion of the shaft member 27 in such a manner as to enlarge the contact surface with the housing 10, and the slidable contact portion 25 provided in the bottom surface of the worm wheel 22. As a result, since the shaft member 27 stably rotates without being inclined, the overload applied to the shaft member 27 is reduced, and it is possible to improve the durability of the shaft member 27. [0052]
Further, in the present embodiment, the cam member 35 is arranged so as to transmit the rotation of the shaft member 27 to the lock bolt 46, and they are assembled by the engagement between the thread ridge 34 and the thread groove 36. Further, since each of these members 27 and 35 is formed by the resin molded component, there is a case that the thread ridge 34 and the thread groove 36 wear and cannot maintain the engagement as a result of the repeated actuation. Further, in the case of coming to the state mentioned above, the lock bolt 4 6 protrudes by the biasing force of the biasing member (the lock spring 42) at a time of returning to the state A in Fig. 6 from the state A' in Fig. 8, and the lock bolt 46 comes into contact with the pin 50 of the slider 38, for example. Accordingly, even if the cam member 35 is separated from the shaft member 27 and moves in the axial direction, the cam member 35 stops by coming into contact with the stopper portion 33. As mentioned above, even in the case that the thread ridge 34 and the thread groove 36 wear, it is possible to prevent the cam member 35 from separating from the shaft member 27.
[53]
Further, in the present embodiment, it is possible to easily assemble the cam member 35 in a state of being separable, by forming the worm wheel 22 and the shaft member 27 as the separated members, and assembling the worm wheel 22 after assembling the cam member 35 to the shaft member 27 . Accordingly, it is possible to improve the assembling workability.
[54]
The steering lock apparatus in accordance with the present invention is not limited to the structure of the embodiment mentioned above, but can be variously changed.
[55]
For example, in the embodiment mentioned above, the stopper portion 33 in the shaft member 27 is formed in the disc shape, however, may be structured by two or more rod-like portions protruding outward in the radial direction. Further, the embodiment mentioned above has the structure in which the worm wheel 22 is provided as the separated body with respect to the shaft member 27, however, the shaft member 27 and the worm wheel 22 may be integrally provided, and the shaft portion 32 and the stopper portion 33 which are provided as the separated bodies may be integrally assembled. Moreover, in the embodiment mentioned above, the shaft member 27 is provided with the thread ridge 34 and the cam member 35 is provided with the thread groove 36, however, the thread groove may be provided in the outer peripheral portion of the shaft member 27 and the thread ridge may be provided in the inner peripheral surface of the cam member 35. Furthermore, in the embodiment mentioned above, the electric motor 19 is arranged to the lid 14, however, may be arranged to the housing 10.

What is Claimed is:

1. A steering lock apparatus comprising:

a housing having one end opened and another end closed, provided with an axial hole portion in a wall portion on the closed other end, and having an insertion hole formed in a predetermined wall portion;

a lid attached to close an opening portion of the housing and provided with a support portion at a position corresponding to the axial hole portion;

an actuator arranged in the housing or the lid, and energized to drive so as to forward rotate or reverse rotate;

a transmission mechanism having a shaft member with one end supported to the support portion of the lid and with another end supported within the axial hole portion of the housing, and the other end being provided with a stopper portion coming into contact with a periphery of the axial hole portion, and the transmission mechanism receiving and transmitting a driving force of the actuator; and

a lock member receiving the driving force of the actuator via the transmission mechanism, and moving between a lock position in which the lock member partly protrudes from the insertion hole of the housing and is capable of engaging with a movable member working with an operation of a steering wheel, and an unlock position in which the lock member retracts into the insertion hole of the housing so as to release engagement with the movable member.

2. The steering lock apparatus according to claim 1, wherein the transmission mechanism further includes a cam member,

wherein at a time of releasing the engagement of the lock member with the movable member, the cam member integrally rotates with the shaft member in a state in which substantially no resistance exists between the movable member and the lock member and moves in an axial direction with respect to the shaft member in a state in which a resistance having a predetermined value or more exists between the movable member and the lock member, and

wherein at a time of engaging the lock member with the movable member, the cam member comes into contact with the stopper portion of the shaft member to stop.

3. The steering lock apparatus according to claim 2, wherein

the cam member is formed substantially in a cylindrical shape to pass the shaft member therethrough and engage the lock member with an outer peripheral portion thereof,

a thread ridge is provided in one of the shaft member and the cam member, and a thread groove is formed in the other member, and

the cam member is integrally rotatable and movable in an axial direction with respect to the shaft member by engagement between the thread ridge and the thread groove.

4. The steering lock apparatus according to claim 3, wherein the transmission mechanism further includes a worm wheel provided as an independent member which is assembled in an end portion of the shaft member on an inverse side to the stopper portion after assembling the shaft member and the cam member so as to be engaged with each other, and wherein the worm wheel receives the driving force of the actuator to transmit to the shaft member.

5. The steering lock apparatus according to claim 1, wherein the transmission mechanism includes a worm wheel receiving the driving force of the actuator to transmit in an end portion of the shaft member on an inverse side to the stopper portion.

6. The steering lock apparatus according to claim 4 or 5, wherein a slidable contact portion coming into contact with the lid is provided in a bottom surface of the worm wheel.