GB2364765A

GB2364765A - Tilt-adjustable steering apparatus

Info

Publication number: GB2364765A
Application number: GB0124584A
Authority: GB
Inventors: Kenji Satoh; Sakae Matsumoto
Original assignee: NSK Ltd
Current assignee: NSK Ltd
Priority date: 1997-10-28
Filing date: 1998-10-27
Publication date: 2002-02-06
Anticipated expiration: 2018-10-27
Also published as: GB2364765B; GB0124584D0

Abstract

The tilt-adjustable steering apparatus comprising a first and second column members 14, 15 connected together to allow relative pivotal movement therebetween, one column member having a movable gear 32 which is engageable with a fixed gear 31 of the other column member to lock said relative pivotal movement. The movable gear 32 is pivotally mounted to its column member about an axis such that said movable gear 32 is allowed to move relatively to said axis to prevent misalignment of the teeth of said movable gear 32 and said fixed gear 31 during engagement.

Description

<Desc/Clms Page number 1> TILT-ADJUSTABLE STEERING APPARATUS BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a tilt-adjustable steering apparatus which is provided with a tilt adjusting mechanism for adjusting the height of a steering wheel in a car or other vehicles in accordance with the physical dimensions of the driver.

Related Background Art As a steering apparatus to be mounted on a car or other vehicles, there is conventionally known a tilt adjustable, or adjusting-type, steering apparatus in which the height of the steering wheel can be adjusted in accordance with the physical dimensions of the driver. The adjustment of the height of the steering wheel in this tilt adjusting-type steering apparatus is generally performed by releasing the lock to move an upper column member in an inclined or sloping manner with respect to a lower column member, so as to thereby set the height of the steering wheel to an arbitrary value, and then locking the upper column member with respect to the lower column member. A mechanism for locking the upper column member and

releasing this lock in this case is a tilt lock mechanism. An example of the tilt lock mechanism is disclosed in Japanese Utility Model Publication No. 2-34145, which is illustrated in Figs. 30 and 31.

In the tilt adjusting-type steering apparatus shown in these drawings, a lower column 52 for supporting a lower steering shaft 51 to be rotatable is fixed to the car body (not shown) through a bracket 53, meanwhile an upper column 55 for supporting an upper steering shaft 54 to be rotatable to which a steering wheel (not shown) is attached is supported by the bracket 53 to allow free slanting movement with tilt shafts 56, 57 as the center thereof, a gear portion 58 fixed on the side of the upper column 55 is caused to mesh with a movable gear member 59 which is supported to freely oscillate by the bracket 53, and then the movable gear member 59 is pressed from the back thereof by the tilt lock mechanism to effect locking. The tilt lock mechanism comprises right and left support hangers 60, 61 with their upper ends respectively supported to freely oscillate by the tilt pivots or shafts 56, 57, a roller support shaft 62 fixed to the lower ends of these support hangers 60, 61, and a roller 63 supported to freely rotate by the roller support shaft 62. The roller support shaft 62 is formed with a tilt lever 64 as a unitary structure so that it is arranged that the roller 63 can be moved in a right and left direction by operating the tilt lever 64.

The movable gear member 59 is locked and is released from the lock by means of the tilt lock mechanism having the above-mentioned structure in the following manner. When the tilt lever 64 in its locked state in Fig. 30 is rotated in a counterclockwise direction in the same drawing against a biasing force of a spring 65, the roller 63 is moved to the right about the tilt pivots 56, 57 to be retracted from a taper portion 66 of the movable gear member 59, whereby the movable gear member 59 is released from the fixed gear 58. In this released state, the upper column 55 is inclined or moved in a slanting manner with respect to the bracket 53 so as to set the steering wheel at a proper position. After that, when the tilt lever 64 is released, the roller 63 is moved to the left by the biasing force of the spring 65 so as to press the taper portion 66, whereby the movable gear member 59 is meshed with the fixed gear 58 to be locked. Upon this locking, the adjustment of the height of the steering wheel is completed.

However, in the above-mentioned tilt adjusting-type steering apparatus, the roller 63 of the tilt lock mechanism is protruded downward, so the roller 63 is positioned around the knees of the driver. As a result, it is feared that the driver's knees be hit by the roller 63 during driving, or the lock of the movable gear member 59 be released.

In order to prevent such accident, it can be devised to cover the roller 63 with a lid or cover. However, with

this arrangement, the number of constituent parts is increased so as to further narrow a space around the knees of the driver disadvantageously.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a tilt adjusting-type steering apparatus which prevents the driver's knees from being hit during driving without increasing the number of the constituent parts or narrowing the space around the driver's knees, and to prevent the lock from being released as a result.

In order to achieve the above object, there is provided according to the present invention a tilt adjusting-type steering apparatus in which a lower steering shaft provided with a steering gear at the lower end thereof and an upper steering shaft provided with a steering wheel at the upper end thereof are coupled with each other by a universal joint, a lower column member for supporting the lower steering shaft to be rotatable is fixed to the body of a car, an upper column member for supporting the upper steering shaft to be rotatable is supported to be freely rockable in a vertical direction by a tilt adjusting shaft mounted on the lower column member to pass through the center of said universal joint, and the upper column member is locked with respect to the lower column member by means of a tilt lock mechanism, characterized in that:

the tilt lock mechanism comprises a fixed gear mounted on one of the lower column member and the upper column member, a movable gear supported to'be freely rockable by the other of the lower column member and the upper column member to be detachably engaged with the fixed gear, a reaction force member disposed in the vicinity of the back surface of the movable gear, and a wedge member to take a lock position at which it is inserted between the reaction force member and the back surface of the movable gear to bring the movable gear into engagement or mesh with the fixed gear and a release position at which it is extracted from the lock position to release the movable gear from the fixed gear.

According to the above invention, it is possible to insert or extract the wedge member into or from a space between the reaction force member and the back surface of the movable gear so as to bring the movable gear into engagement with the fixed gear to be locked, and it is also possible to release the movable gear from the fixed gear. Further, the wedge member is covered with the reaction force member while it is disposed at the lock position so that there is no need to provide, for example, a special cover for that, and it is no possibility that the driver's knees are hit by this wedge member to release the lock of the movable gear to the fixed gear.

The tilt adjusting-type steering apparatus of the present invention can be arranged such that the fixed gear

has a plurality of teeth extended in the lateral direction and formed on an outer peripheral surface of said one of the lower column member and the upper column member, while the movable gear comprises a pin inserted through the support portions formed on the other of the above- mentioned outer peripheral surfaces in parallel to the tilt shaft, a movable gear main body having a through hole to pass the pin at the base end thereof and a plurality of teeth capable of meshing with the teeth of the fixed gear at the tip end thereof, and a bush interposed between the outer peripheral surface of the pin and the inner peripheral surface of the through hole, and special form portions into which a part of the bush is thrust when a force in a direction of twisting the movable gear main body is caused to work due to the mesh between the of the fixed gear teeth and the teeth of the movable gear are formed on one of the outer peripheral surface of the pin and the inner peripheral surface of the through hole.

Since it is possible for a part of the bush to be thrust into the special form portion according to the tilt adjusting-type steering apparatus having such structure, the movable gear main body can be rotated to that extent in the twisting direction around the vicinity of the bush. As a result, when the movable gear main body is caused to rock to make the teeth thereof mesh with the teeth of the fixed gear in a state where the degree of parallelism between the teeth of the fixed gear and the teeth of the

movable gear main body is not sufficient after completion of assembly, the teeth of the fixed gear and the teeth of the movable gear are meshed with each other with precision and the movable gear main body is rotated in the twisting direction correspondingly. That is, as the part of the bush is thrust into the special form portion, the movable gear main body is rotated in accordance with the meshed state between the teeth of the movable gear and the teeth of the fixed gear. As a result, an excellent meshed state with a high degree of parallelism can be realized between the teeth of the fixed gear and the teeth of the movable gear in the opposite way.

Furthermore, the tilt adjusting-type steering apparatus of the present invention can be arranged such that the fixed gear is cast either in a lower bracket or an upper bracket. With this structure, since the fixed gear is cast either in the lower bracket or the upper bracket, it is no longer necessary to employ a method for fixing the fixed gear by welding or by use of a caulking pin or a bolt and a nut, unlike in a conventional structure. As a result, a troublesome installing step of the fixed gear can be saved and the number of assembling steps and that of the constituent parts can be reduced, whereby the manufacturing cost can be decreased. Moreover, since the fixed gear is cast in the bracket, it can be installed precisely and secured for a long time.

Further, the tilt adjusting-type steering apparatus

of the present invention can be arranged such that at least a part of the teeth in the width direction out of at least one of the teeth of the movable gear and the teeth of the fixed gear are formed in accordance with the regular gear specifications, and the remaining teeth are formed to generate a predetermined clearance with the teeth of the other gear. With this structure, at least a part of the teeth in the face width direction of at least one of the teeth of the movable gear and the teeth of the fixed gear are formed in accordance with the regular gear specifications, and the remaining teeth are formed to generate a predetermined clearance with the teeth of the other gear. As a result, if at least a part of the teeth in the width direction out of the teeth formed in accordance with the regular gear specifications of one of the engagement members are meshed with the teeth of the other of the engagement members in a normal use, a mesh with a sufficient strength can be realized even when the parallelism of the both teeth is slightly divergent because a load applied on each tooth is small, thereby generating no backlash. Also, like in the case of collision, if the steering apparatus receives an excessive load input, the remaining teeth which are arranged to have a predetermined clearance with the teeth of the other gear can be meshed with the teeth of the other gear so that a mesh with a sufficient strength can be realized and the steering apparatus can endure the

excessive load satisfactorily. Further, it is no longer necessary to maintain a remarkably high processing accuracy, unlike in the conventional apparatus, and it is also no longer required to fix the engagement members by welding or a bolt and a nut in a state where the teeth of the both members are meshed with each other. As a result, the manufacturing cost can be reduced, the number of the constituent parts can be decreased, and the weight of the steering apparatus can be lightened.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a longitudinal cross-sectional view of a tilt adjusting-type steering apparatus according to a first embodiment of the invention.

Fig. 2 is a bottom plan view of the tilt adjusting-type steering apparatus according to the first embodiment of the invention.

Fig. 3 is an enlarged view of a wedge member disposed at a lock position according to the first embodiment. Fig. 4 is an enlarged view of the wedge member disposed at a release position.

Fig. 5 is a view of the steering apparatus of Fig. 1, taken along the line X-X.

Fig. 6 is an enlarged view of a base end portion of a movable gear according to the first embodiment.

Fig. 7 is a view for showing the form of a special form portion of the movable gear according to the first

embodiment. Fig. 8 is a view for showing another form of the special form portion of the movable gear according to the first embodiment.

Fig. 9 is an enlarged view of the base end portion of the movable gear according to a variation of the first embodiment.

Fig. 10 is a longitudinal cross-sectional view of a tilt adjusting-type steering apparatus according to a second embodiment of the invention.

Fig. 11 is a bottom plan view of the tilt adjusting-type steering apparatus according to the second embodiment of the invention.

Fig. 12 is a longitudinal cross-sectional view of a tilt adjusting-type steering apparatus according to a third embodiment of the invention.

Fig. 13 is a top plan view of the tilt adjusting- type steering apparatus according to the third embodiment of the invention.

Fig. 14 is a longitudinal cross-sectional view of a tilt adjusting-type steering apparatus according to a fourth embodiment of the invention.

Fig. 15 is a longitudinal cross-sectional view of a tilt adjusting-type steering apparatus according to a fifth embodiment of the invention.

Fig. 16 is a bottom plan view of the tilt adjusting-type steering apparatus shown in Fig. 15.

Fig. 17 is a longitudinal cross-sectional view of a tilt adjusting-type steering apparatus according to a sixth embodiment of the invention.

Fig. 18 is a bottom plan view of the tilt adjusting-type steering apparatus shown in Fig. 17. Fig. 19 is a longitudinal cross-sectional view of a tilt adjusting-type steering apparatus according to a seventh embodiment of the invention.

Fig. 20 is a bottom plan view of the tilt adjusting-type steering apparatus shown in Fig. 19, seen from below.

Fig. 21A is a plan view of the movable gear, while Fig. 21B is a side view of the movable gear.

Fig. 22 is a side view of teeth in a part formed in accordance with the regular gear specifications.

Fig. 23 is a side view of teeth in a part in which a clearance is formed between both the teeth of the fixed gear and the movable gear.

Fig. 24 is a plan view of the movable gear (an engagement member on the movable side) and a fixed gear. Fig. 25 is a vector diagram for showing amount of deviation of the movable gear (the engagement member on the movable side) and the fixed gear.

Fig. 26 is a view for showing a meshed state in a conventional apparatus.

Fig. 27 is a view for showing a meshed state in the first embodiment.

Fig. 28 is a plan view of the movable gear (the engagement member of the movable side).

Fig. 29A is an enlarged view of the portion X of Fig. 28 according to an eighth embodiment, Fig. 29B is an enlarged view of the portion X of Fig. 28 according to a first variation of the eighth embodiment, Fig. 29C is an enlarged view of the portion X of Fig. 28 according to a second variation of the eighth embodiment, Fig. 29D is an enlarged view of the portion X of Fig. 28 according to a third variation of the eighth embodiment, and Fig. 29E is an enlarged view of the portion X of Fig. 28 according to a fourth variation of the eighth embodiment.

Fig. 30 is a longitudinal cross-sectional view of a conventional tilt adjusting-type steering apparatus. Fig. 31 is a view of the steering apparatus of Fig.

30, taken along the line XV-XV. DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. (First Embodiment) An embodiment of a tilt adjusting-type steering apparatus according to the present invention is shown in Figs. 1, 2, 3 and 4. Fig. 1 is a longitudinal cross- sectional view, and Fig. 2 is a bottom plan view of the tilt adjusting-type steering apparatus, while Fig. 3 is a view for showing a state a movable gear 32 (which is

described later) is disposed at a lock position. Then, Fig. 4 is a view for showing a movable gear 32 disposed at a release position. The vertical and horizontal directions in the following description are determined from the position of the driver who operates the steering wheel. More specifically, the right part in Fig. 1 is determined as the "above", the left part as the "below", the upper part as the "front", and the lower part as the "behind". Further, in Fig. 2, the upper part is determined as the "left", and the lower part as the "right". The term "lock" is used both for the movable gear 32 and an upper column member 14 (which is described later). That is, this term is used such that the movable gear 32 is locked with a fixed gear 31 (which is described later) , or that the upper column member 14 is locked with a lower column member 15 (which is described later).

The tilt adjusting-type steering apparatus 10 shown in these drawings is attached to vehicles such as a car to transmit a rotation of a steering wheel (not shown) to the wheels (not shown) . The apparatus 10 is comprised of an upper steering shaft 11, a lower steering shaft 12, a universal joint 13, the upper column member 14, the lower column member 15 and the tilt lock mechanism 16 as its main constituent members. Description will be made on these members in the named order.

The upper steering shaft 11 is provided with a steering wheel mounting portion 11a at the upper end

thereof (in the right part in Fig. 1) , and a steering wheel (not shown) is attached to this wheel mounting portion 11a. The upper steering shaft 11 is also provided with a universal joint 13 at the lower end thereof. Bearings 21, 22 are interposed between the upper column member 14 and the upper part and the lower part of the steering shaft 11, respectively.

A steering gear (not shown) is fixed to the lower end of the lower steering shaft 12 (in the left part in Fig. 1). For example, in a rack and pinion type steering apparatus, a steering gear is meshed with a steering rack, and the steering rack is coupled to the wheels through a tie rod, a ball joint, a knuckle arm, etc. The above-mentioned universal joint 13 is coupled to the upper end of the lower steering shaft 12. The lower steering shaft 12 is supported to be rotatable by bearings (not shown) which are interposed between the lower steering shaft 12 and the lower column member 15.

The universal joint 13 is interposed, as described above, between the lower end of the upper steering shaft 11 and the upper end of the lower steering shaft 12 so as to couple the both steering shafts 11, 12 together to be flexible. With the interposition of this universal joint 13, ever when the axial center 11b of the upper steering shaft 11 is not in alignment with the axial center 12b of the lower steering shaft 12, that is, ever when the axial center 11b of the upper steering shaft 11 is

inclined with respect to the axial center 12b of the lower steering shaft 12, a rotation of the upper steering shaft 11 caused by a rotation of the steering wheel is smoothly transmitted to the lower steering shaft 12 through the universal joint 13. In this case, if the axial center 11b of the upper steering shaft 11 is inclined with respect to the axial center 12b of the lower steering shaft 12, a straight line which makes a right angle with a plane formed by these two axial centers 12b, 11b and passes a point at which extensions of the two axial centers 12b, 11b are crossing each other is determined as the center 13b of the universal joint 13. With such determination, the axial centers 25a, 25a of tilt shafts 25, 25 coincides with this center 13b of the universal joint 13.

The upper column member 14 is comprised of a cylindrical column main body 23 and an upper bracket portion 24 fixed to the lower end of the column main body 23 as a unitary integral structure. The upper bracket portion 24 is formed in a U shape which is opened downward to cover most of the above-mentioned universal joint 13. Right and left through holes (not shown) are respectively formed on the right and left sides of the lower end of the upper bracket portion 24, and the tip ends of the tilt shafts 25, 25 are inserted into these through holes via bushes (not shown) . The axial centers 25a, 25a of these tilt shafts 25, 25 are passed through the center 13b of the universal joint 13. Support portions 14a, 14a are

formed in the hind portion on the outer peripheral surface of the upper column member 14 (in the lower part in Fig. 1) . Through holes 14b, 14b which are in parallel to the axial centers 25a, 25a of the tilt shafts 25, 25 are formed on these support portions 14a, 14b. A pin 26 for supporting a movable gear 32 which is described later to rock freely are inserted into these through holes 14b, 14b. It should be noted that this pin 26 constitutes a part of the tilt lock mechanism 16 which is described later. The whole structure of the upper column member 14 supports the upper steering shaft 11 to be rotatable by means of the above-mentioned bearings 21, 22 which are interposed between the upper end of the column main body 23 and the upper steering shaft 11, and between the upper end of the upper bracket portion 24 and the upper steering shaft 11, respectively, and is supported to be movable in a slanting manner (to be freely rockable) by the lower column member 15 which is described next, by means of the tilt adjustment shafts or pivots 25, 25.

The lower column member 15 has a column main body 28 and a cylindrical portion 29 formed integrally with the column main body. The cylindrical portion 29 has a support portion (not shown) which is formed to be sandwiched from right and left by the above-mentioned upper bracket portion 24. The tip ends of the tilt adjustment shafts 25, 25 are inserted into these support portions. The column main body 28 is fixed to an

installment panel (not shown) of the car body through a mounting portion (not shown). The whole structure of the lower column member 15 supports the lower steering shaft 12 to be rotatable through bearings (not shown) and supports the upper column member 14 to freely rockable by means of the tilt adjustment shafts 25, 25. A compression spring 30 is interposed between the lower column member 15 and the upper column member 14, as shown in the lower part of Fig. 1 and in the lower part of Fig. 2, whereby the upper column member 14 is biased against the lower column member 15 upward (in the counter- clockwise direction in Fig. 1) with the tilt adjustment shafts 25, 25 as the centers thereof. The biasing force of this compression spring 30 is set to offset the weights of the upper steering shaft 11, the upper column member 14, the steering wheel, etc. , so as to easily adjust the height of the steering wheel.

The tilt lock mechanism 16 is comprised of the above-mentioned pin 26, a fixed gear 31 which is provided on the side of the lower column member 15, the movable gear 32 which is provided on the side of the upper column member 14, a wedge member 33, an operation arm 34 having this wedge member 33, and a reaction force member 35, as the main constituent members thereof.

The above-mentioned constituent members from the fixed gear 31 to the reaction force member 35 will be fully described below in the named order.

The fixed gear 31 is a block-like member which is fixed to the hind surface (a lower part in Fig. 1) 29a on the outer peripheral surface of the cylindrical portion 29, and is provided with a lot of teeth 31a toward the rear direction. These teeth 31a of the fixed gear are formed such that the teeth are extended in a right and left direction or a transverse direction to the axial direction of the steering shaft 11 or 12, and the teeth surfaces are arranged to form a circular arc about the tilt adjustment shafts 25, 25.

The movable gear 32 is comprised of a base end portion 32', and a main body 32", and this base end portion 32' is supported to be rockable by the pin 26 which is inserted into the support portions 14a, 14a of the above-mentioned upper column member 14. The movable gear main body 32" is formed of a plate member and is provided with a lot of teeth 32a which can be meshed with the fixed teeth 31, on the front surface of the tip end side thereof. A taper surface 32b is formed on the reverse side to the teeth 32a of the movable gear 32. A protrusion 32c is formed backward on the base end side of the movable gear 32. This protrusion 32c is arranged to separate the teeth 32a of the movable gear 32 from the teeth 31a of the fixed gear 31 by forcibly pressing the tip end of the movable gear 32 down in Fig. 1 when the upper end of the operation arm 34 which is described later is brought into contact with this protrusion 32c.

The wedge member 33 is formed to protrude downward (in Fig. 1, which is leftward in Fig. 2) at the central part of the operation arm 34 in the lateral direction, which is elongated in the lateral direction. At the tip end side of the wedge member 33, there is provided an inclined surface 33b having an angle 8 of inclination with respect to a reference surface 33a on the back surface side which is in contact with the reaction force member 35 described later. The reference surface 33a and the inclined surface 33b constitute a thin tapered wedge portion. The angle 8 of inclination of the inclined surface 33b is set to correspond to the taper surface 32b of the movable gear 32, that is, to satisfy the relation that tan 6 < a where the maximum coefficient of friction between the taper surface 32b and the inclined surface 33b is a. For this reason, the wedge member 33 is not moved from the lock position shown in Fig. 3 to the right in the same drawing when, for example, a force in a drawing direction (to the right in Fig. 3) is caused to act from the side of the movable gear 32. If the angle of inclination does not satisfy the relation of tan 9 < a , it is possible to prevent the wedge member 33 from moving in the drawing direction (to the right in Fig. 3) by means of a biasing force of a spring 36 which is described later.

The operation arm 34 has the above-mentioned wedge member 33 at its central part in the lateral direction, and the center of rocking movement 34a at its base end

side. An operation lever 34b is fixed to the tip end of the operation arm 34. The center 34a of the rocking movement is oriented to a direction perpendicular to a plane including the axial center 11b of the upper steering shaft 11 and the axis 25a of the tilt adjustment shaft or pivot 25, and the operation arm 34 conducts a swinging operation on a plane parallel to this plane including the axial center 11b and the axis 25a. The operation arm 34 is biased in the counterclockwise direction in Fig. 2 by means of a wire spring 36 which is provided in the vicinity of the center 34a of the rocking movement. With this biasing, the wedge member 33 takes the lock position shown in Fig. 3, that is, the position at which it is inserted between the taper surface 32b and the reaction force member 35, and the release position shown in Fig. 4, that is, the position at which it is drawn to the left in Fig. 4 from the lock position by the clockwise operation of the operation lever 34b shown in Fig. 2.

The reaction force member 35 is formed in the vicinity of the taper surface 32b of the movable gear 32 in Fig. 1 and Fig. 3 as a part of the upper bracket portion 24 of the upper column member 14. A surface of the reaction force member 35 opposed to the taper surface 32b is a pressurization surface 35a. The wedge member 33 is inserted into between this pressurization surface 35a and the taper surface 32b to take the lock position, whereby the teeth 32a of the movable gear 32 are meshed with the

:eeth 31a of the fixed gear 31 to be locked.

As shown in Fig. 6 which is an enlarged view of a part 'n Fig. 2, a through hole 32d is formed in the lateral direction at the base end of the movable gear main body ?2. A flanged bush 43 is inserted in the inner peripheral tzur-ace o- this through hole 32d, and the pin 26 which _s inserted into the support portions 14a, 14a of the upper column member 14 is inserted in the inner peripheral :ur-ace o- the bush 43. The special form portions 32e, 12e are formed on the inner peripheral surface of the =:zrough hole 32d, as shown in Fig. 7. These special form zor tions 32e, 32e are formed of a plurality of saw-toothed rotuberances, and are formed in parts, i.e., upper and _ower parts on the inner peripheral surface of the through ole 32d. These special form portions 32e, 32e are :_=anged to be thrust by the bush 43 when a force in t'_ne direction of twisting the movable gear 32 is caused to _..t on the movable gear 32. More specifically, when a _atera- force is caused to act on the teeth 32a at the =_p end of the movable gear 32, the special form porti ons 32e, 32e are thrust into the outer peripheral surface of .:.e bush 43, thereby allowing the tip end a s1 i ght movement the Lateral direction. As a result, the teeth 32a a-e =ranged to be meshed with the fixed teeth 31a with c=ecision so as to remove a tilt backlash of the upper column member 14 with respect to the lower column member _. This a-rangement will be described later again. T:ne

speci a= form portions 32e, 32e may be formed in part of the inner peripheral surface of the through hole 32d, as shown in Fig. 7, or may be provided over the entire inner peripheral surface of the through hole 32d, as indicated cy a reference numeral 32f in Fig. 8. In addition, the soecia_ form portions 32e, 32e may be formed on the outer ceripheral surface of the pin 26, instead of on the inner peripheral surface of the through hole 32a, though wh_ch is not shown in the drawing.

Next, description will be made on an operation of -'net tilt adjusting-type steering apparatus 10 having the above-mentioned structure.

In order to adjust the height of the steering whee_, f-rst tae 'lock of the movable gear 32 by the wedge member 33 is released. When the operation lever 34b is drawn i n the clockwise direction in Fig. 2 to cope with t::e b-asiny force of the spring 36, the whole operation a=m 3' is rotated in the cl cckwise d-rection around the censer a of =he rock" ng movement. W@_th this rotati on of c::e ccerat-cn arm 34, the wedge member 33 is moved to the rice in Fig. 3, and is drawn out of the space between the tapir surface 32b of the movable gear 32 and the pressuri zati On surface 35a of the reaction force member 35. When t^e wedge member 33 is further moved to the right, the hind end thereof is brought into contact with the protrusion 3=c of zhe movable gear 32, as shown in Fig. 4, and t::e mc-vable year 32 is caused to rock downward in Fig. 4 w-_a

the pin 26 as the center of the rocking movement, whereby the lock and the mesh of the teeth 32a of the movable gear 32 on the side of the upper column member 14 with the teeth 31a of the fixed gear 31 on the side of the lower column member 15 are released. When the taper surface 32b of the movable gear 32 is brought into contact with the pressurization surface 35a of the reaction force member 35, the rocking movement of the movable gear 32 is stopped, thereby stopping a rightward movement of the wedge member 33 by means of the protrusion 32c of the movable gear 32. In this state, the wedge member 33 is disposed at the release position shown in Fig. 4. When the wedge member 33 is disposed at the release position in this manner, the upper column member 14 can be inclined with respect to the lower column member 15, whereby it becomes possible to adjust the height of the steering wheel.

After the steering wheel is adjusted to be at an appropriate height, the operation lever 34b is released. Then, the operation arm 34 is rotated in the counter- clockwise direction in Fig. 2 by the biasing force of the spring 36, and the wedge member 33 is moved to the left in Fig. 3. The wedge member 33 is moved to the left in such a manner that the reference surface 33a thereof slides on the pressurization surface 35a of the reaction force member 35, so that the taper surface 32b of the movable gear 32 is pushed upward in Fig. 3 by means of the inclined surface 33b. In this manner, the teeth 32a

of the movable gear 32 are meshed with the teeth 31a of the fixed ;ear 31 to be locked. Thus, the upper column member 14 is locked with respect to th.e lower column member 15 to thereby complete the height adjustment of the steering wheel.

In the tilt adjusting-type steering apparatus 10 with the above-mentioned structure and operation, the wedge member 33 of the tilt lock mechanism 16 can be made thin to have a small thickness (the vertical size in Figs. 1, 3 and 4'. Since the wedge member 33 is covered with the reaction force member 35, the locking, mechanism toes not hit the driver's knees, and therefore, it is no z#ossibi 1 it@.r of releasing the lock of the movable gear 32 owing to this hit. The above description that the wedge member 33 is made to be thin only means that the size of t:r,e wedge member can be set smaller compared to the diameter o= a roller 63 of the prior art (see Fig. 30).

Accor--ing to the first embodiment of the present ;avention, a tilt backlash of t`@e upper column member 14 w * th respect to the lower column. member 15 can be prevented. ,.,at is, as shown in Fig. 7, the special form portions 32e, 32e are formed on the through hole 32d at the base end of the movable gear 32, and when a force is caused to act in a direction of twisting the movable teeth 32a a- the tip end of the movable gear 32, the special form portions 32e, 32e are arranged to be thrust into a part o= th a bust 43. As a result, l `, for example, the fixed

-eeth 31a and the movable teeth 32a are meshed with each other in a state in which the degree of parallelism is not sufficient, the teeth 32a are first slightly moved to the teeth 31a of the fixed gear to be engaged therewith properly, and then, the special form portions 32e, 32e are thrust into the bush 43 correspondingly. As a result, no back'-ash is generated between. the teeth 31a of the fixed Gear and the teeth 32a of the movable gear, and no tilt acklash is brought about between the lower column member :.5 and the upper column member 14.

According to a variation of the first embodiment, as sown in Fig. 9, the through hole 32d on the base end side c= the movable gear main body 32 has a cross section formed c_' inwardly convex surface. That is, the inner diameter cf the inner peripheral surface of the through hole 32d _s the minimum at the center thereof in the axi a1 di rection and gradually increases as it goes outward. In this manner, the teeth at the tip end of the movable gear main tz,dv 32 can rock in the lateral direction about the center c_' this t:nrough hole, thereby -rendering a proper mes:n tetween the teeth of tae fixed gear and the teeth of the movable gear.

Also, the same structure as that of the vicinity of t:-e through hole 32d of the movable gear main body 32 of t:-,e first embodiment may be applied to the vicinity atove-mencioned through hole (not shown) of the upper br cket 2'1 to which tile tilt shaft 25 is inserted. That

is, the special form portions may be formed on the inner peripheral surfaces of through holes for the tilt shaft 25 and the bush may be interposed between this inner peripheral surface and the outer peripheral surface of she tip end of the tilt shaft 25.

Generally, the concentricity of the through holes for :he tilt adjustment shafts which are formed at the right and left sides of the upper bracket 24 and the concentricity of two though holes for the same tilt adjust:-ient shafts which are formed at the right and left sides of the lower bracket 29 are essential. If these concenzricities deviate, a slow tilt adjusting operation or other operational problems will occur.

Accordingly, in the present embodiment, it is arranged, as described above, to provide the special form zortions and the bush, so that even if any of the roncentricities between the through holes of the upper 'r=acket and the through holes 29d of the lower bracket ...'.ight'_y ceviates, the same effects as if the deviat,_ng concentricity has been corrected can be obtained since z:ie special form portions are thrust into the bush and smooth tilt operation can be conducted.

As described above, according to the present e:abodiment, one or the lower column member and the upper column member is provided with a fixed gear, while the c--her i s provided with a movable gear to be meshed with z:'--is fixed gear. The through hole formed on the

'ase end side of this movable gear or the pin inserted -herethrough is provided with special form portions which can be thrust into the bush. With such arrangement, when -he degree of parallelism between the teeth of the fixed cear and the teeth of the movable gear is not satisfactory,

the teeth of the movable gear can move to the teeth of the fixed gear to make the mesh _ierewith excellent. As a result, it is possible to crevent a tilt backlash without using a bolt and a nut. '=.'ldt is, _- is possible to reduce the number of the constituent parts, and to save a space for such parts. _-".:rther, i_ is also possible to reduce the number of the assembling steps, so as to ef=ectively prevent a tilt Lack'_ash.

sZecond Embodiment) A second embodiment of the present invention is shown ig. 10 and Fig. 11. It should be noted that Fi g. ":0 _@ a vjeW corresponding :O Fig. _ .7L the first embod=men=, a Fig . 11 is a v-;?:.i corresponding to -;_c. 2.

The second embodiment is largely di f-erent from t~e =_rst embodiment in t1e d_rect;on of inserting and ==moving a wedge member 4? whic`l is reverse to that 'n to first embodiment. In the ';following description, drent arrangements 'rpm the first embodiment will be mainly explained. The same arrangements as those in the =_=st embodiment will be given the same reference

numbers and description thereof will be omitted, which manner is applied to third and fourth embodiments described later.

As shown in Fig. 11, the wedge member 41 is provided at the tip end of an operation arm 42, while a- rocking center 42a is provided at the base end of the operation arm 42. Then, an operation lever 42b is provided on the reverse side to the wedge member 41 using this rock_ng center 42a as the reference. The operation arm 42 is :,_ased i n the counterclockwise direction by the spring .50.

With the above-mentioned arrangement, if the coeration lever 42b is drawn to the right in Fig. 11 to cope with the biasing force of the spring 36, the whole operation arm 42 is rotated clockwise with the rock_ng center 42a as the center of rotation, and the wedge member 4'_ is moved to the left i n Fig. 10 or Fig. 11 to be disposed G= the release position, whereby the lock and the mesh the teeth 32a of the movable gear 32 with respect _o z:-e teeth 31a of the -Fixed gear 31 _s released. As a resL_t, becomes possible to adjust the height of the steer_ng w:,eel. After this height adjustment, if the operation =ever 42b is released, the operation arm 42 is rotated ccunter-clockwise by the spring 36, whereby the wedge member 41 is moved from the release position to the right Fig. 10 or Fig. 11 to be inserted between the taper s_rface 32b of the movable gear 32 and the pressurization

surface 35a of the reaction force member 35. Thus, the wedge member 41 is disposed at the lock position. In this manner, the mesh and the lock of the movable gear 32 with respect to the fixed gear 31 is conducted, and the lock of the upper column member 14 with respect to the lower column member 15 is also conducted, whereby the height adjustment of the steering wheel is completed.

The operation and the effects of the above-mentioned second embodiment are the same as those of the first embodiment. Specifically, the wedge member 33 of the tilt lock mechanism 16 can be made thin to have a small thickness (the vertical dimensions in Fig. 10). 'Since covered with the reaction force member 35, the wedge member 33 does not hit the driver's knees, and therefore, it is no possibility of releasing the lock of the movable gear 32.

(Third Embodiment) A third embodiment of the present invention is shown in Fig. 12 and Fig. 13. It should be noted that Fig. 12 is a view corresponding to Fig. 1 of the first embodiment mentioned above, while Fig. 13 is a top plan view of the embodiment.

The third embodiment is different from the first embodiment in that the tilt lock mechanism 16 disposed in a lower part in Fig. 1 in the first embodiment is disposed in an upper part in Fig. 12. Since the other arrangements are the same as those of the first embodiment,

full description thereof will be omitted. According to the third embodiment, there is no possibility at all that the tilt lock mechanism 16 including the wedge member 32 may hit the driver's knees. As a result, there is also no possibility that the driver's knees strike the wedge member 33 and release the lock of the movable gear 32 with respect to the fixed gear 31. (Fourth Embodiment) Fig. 14 shows a fourth embodiment of the present invention. It should be noted that Fig. 14 is a view corresponding to Fig. 1 of the first embodiment.

In each of the first to third embodiments described above, the fixed gear 31 is provided on the side of the lower column member 15, while the movable gear 32 is provided on the side of the upper column member 14. On the other hand, in the present fourth embodiment, the movable gear 32 is provided on the side of the lower column member 15, while the fixed gear 31 is provided on the side of the upper column member 14. That is, the present invention is also applicable to a tilt adjusting-type steering apparatus in which the fixed gear 31 and the movable gear 32 are disposed in the reverse way as mentioned above.

The operation and the effects of the present fourth embodiment are the same as those of the first and second embodiments, and description thereof will be omitted.

It is also possible to combine the present fourth

embodiment with the above-described second embodiment so as to reverse the direction of inserting and removing the wedge member 45 to the direction shown in Fig. 14. The effects and operation in this case are the same as those in the second embodiment.

Further, it is possible to combine the present fourth embodiment with the above-described third embodiment so as to dispose the tilt lock mechanism 16 in an upper part of the apparatus, instead of a lower part in Fig. 14. The effects and operation in this case are the same as those in the third embodiment.

(Fifth Embodiment) A fifth embodiment of the present invention is shown in Fig. 15 and Fig. 16. Fig. 15 is a longitudinal cross-sectional view of a tilt adjusting-type steering apparatus according to the fifth embodiment, while Fig. 16 is a bottom plan view of the tilt adjusting-type steering apparatus shown in Fig. 15. In any of the first to third embodiments described above, as a spring 36 for returning the operation arm 34, a torsion coil spring (36) is disposed around the rocking center 34a. However, instead of such arrangement, a compression coil spring 46 is interposed between the protrusion 32c of the movable gear 32 and the operation arm 34. With this arrangement, when the operation arm 34 is released in order to adjust the height of the steering

wheel, if the operation arm 34 is not brought into contact with the protrusion 32c of the movable gear 32, the movable gear 32 can be rotated to be released owing to the biasing force of the compression coil spring. For this reason, the tilt lock can be released with a minimum amount of operation. Also, when the movable gear 32 is to be released, no metallic part is brought into contact therewith, so that a higher operability can be obtained. (Sixth Embodiment) A sixth embodiment of the present invention is shown in Fig. 17 and Fig. 18. Fig. 17 is a longitudinal cross-sectional view of a tilt adjusting-type steering apparatus according to the sixth embodiment, while Fig. 18 is a bottom plan view of the tilt adjusting-type steering apparatus shown in Fig. 17.

In the fifth embodiment described above, the compression coil spring 46 is interposed between the protrusion 32c of the movable gear 32 and the operation arm 34. However, in the present sixth embodiment, instead of such arrangement, a torsion coil spring 47 is interposed between the protrusion 32c of the movable gear 32 and the operation arm 34.

This torsion coil spring 47 is provided around an extended portion 26awhich isformed by slightly extending the rocking center pin 26 of the movable gear 34, and the both ends of this torsion coil spring 47 are bent in the form of a hook to be engaged with the operation arm 34

and the protrusion 32c of the movable gear 32.

With this arrangement, when the operation arm 34 is released in order to adjust the height of the steering wheel, even if the operation arm 34 is not brought into contact with the protrusion 32c of the movable gear 32, the movable gear 32 can be rotated to be released owing to the biasing force of the coil spring 47. For this reason, the tilt lock can be released with a minimum amount of operation. Also in this case, when the movable gear 32 is to be released, no metallic part is brought into contact therewith, so that an excellent operability can be obtained.

Fig. 19 is a longitudinal cross-sectional view of a tilt adjusting-type steering apparatus according to a seventh embodiment of the present invention, while Fig. 20 is a bottom plan view of the tilt adjusting -type steering apparatus shown in Fig. 19, seen from below.

First, a basic structure of the tilt adjusting-type steering apparatus will be described with reference to Fig. 19 and Fig. 20. A steering shaft is divided into a front steering shaft 112 and a rear steering shaft 111 to be coupled together with a universal joint 113. The front steering shaft 112 is accommodated into a lower bracket 115 which is fixed to the car body, while the rear steering shaft 111 is accommodated to be rotatable freely through bearings 121 and 122 in an upper bracket 114 which is provided to freely rock with respect to the lower

bracket 115. The upper bracket 114 is arranged to rock around a pivot 125 which is provided on a side surface of the lower bracket 115.

In the seventh embodiment, a movable gear 132 pivotally supported by a pivot or pin 126 is provided on the upper bracket 105, while a fixed gear 131 fixed in a manner described later is provided on the lower bracket 115. Below the movable gear 132, an operation arm 134 provided with a wedge member 133 having a protrusion 133c is extended. Below the wedge member 136, there is provided a reaction force member 135 serving as a fixed member.

Accordingly, when the operation arm 134 is caused to rock, the movable gear 132 is pushed up by the wedge member 133 and the protrusion 133c, the teeth 132a of the movable gear 132 are engaged with the teeth 131a of the fixed gear 131, and in this state the wedge member 133 is locked between the movable gear 131 and the fixed member 131. On the other hand, when the operation arm 134 is caused to rock in a reverse direction, the wedge member 133 is released from the movable gear 131 to abut against the protrusion 132c for releasing the movable gear 131, whereby the teeth 131a of the movable gear 131 is forcibly released from the engagement with the teeth 131a of the fixed gear 131.

Further, in the present seventh embodiment, the lower bracket 115 is made from aluminum or magnesium by die

casting, and when this lower bracket 115 is formed by die casting, the fixed gear 131 is cast in the same die. In this manner, it is possible to attach the fixed gear 131 to the lower bracket 115 accurately to be secured for a long term, while reducing the manufacturing cost of the apparatus.

Further, in the seventh embodiment, since the extended portion 131b extended from the fixed gear 131 is buried in the lower bracket 115, the fixed gear 131 is installed more securely.

Further in the seventh embodiment, the above- mentioned lower bracket 115 is made from aluminum or magnesium by die casting, and when this lower bracket 115 is formed by die casting, the fixed gear 131 is cast in the same die. Accordingly, it is no longer required to employ a method of fixing an engagement member on the fixed side by welding or by use of a caulking pin, or the like, unlike in the conventional manner. As a result, a troublesome installing process for fixing the fixed gear 131 can be saved, the number of assembling steps and the constituent parts can be reduced, whereby the manufacturing cost can be decreased. Moreover, since the fixed gear 131 is cast in the lower bracket 115, it is possible to install the fixed gear 131 on the lower bracket 115 accurately to be secured for a long term.

Next, an eighth embodiment of the present invention will be described. The eighth embodiment relates to the

form and t e structure of teeth of a movable gear and those of a fixed gear. Basic arrangements of the tilt adjusting-type steering apparatus other than the forms and struc:ures of the teeth may be those of the first embodimen_ shown in Figs. 1 and 2, those of the seventh embodiment shown in Figs. 19 and 20, or those of any of the foreging embodiments.

The eighth embodiment will be described below as having the structure shown in Fig. 19 and Fig. 20. Fig . 21A is a plan view of the movable gear (an engagemen= member on the movable side) , Fig. 21B is a side view of t-e movable gear (the engagement member on the movable site) , Fig. 22 is a side view of teeth in a portion =ormed n a-cordance with the regular gear specifications, Fig. 2-, is a side view of teeth in a portion in which a clearance is formed between the teeth of both the gears, Fig. 24 _Js a plan view of the movable gear (the engagement :,:ember on =he movable side) and the fixed gear (an engagemen= member on the fixed side), Fig. 25 is a schematic view for showing roc:ting movement amounts or t:ze movab_e gear (t:ne engagement member on the movable s'de) and the fixed gear (the engagement member on the fixed side), Fig. 26 is a view =or showing a state of a mesh in a conventional apparatus, and Fig. 27 is a view for sho,.,;inc a state of the mesh in the eighth embodiment.

As shown in Figs. 21A and 21B, part 32h of the teeth 32a of the movable gear 32 are formed in accordance with

the regular gear specifications (Fig. 22), and the remaining part 32i are formed to have a small teeth thickness so as to generate a predetermined small clearance with the teeth 31a of the fixed gear 31 (Fig. 23). Wher. the tooth thickness is formed to be thin, the par: 32h may be formed by crowning or may be added with a seep portion.

Accordingly, in a normal use, when the teeth in the par= 32h o_' the movable gear 32 formed in accordance with the regular gear specifications are meshed wi th the teeth 31a of the fixed gear 31, a load applied on each of the teeth 31a and 32a is small, so that even if the parallelism between the movable gear 32 and the fixed gear 31 slightly deviates, a mesh with a sufficient strength can be attained so that no backlash is generated.

As shown in Fig. 24, i f an angle of deviation of the paral lel ism between the movable gear 32 and the fixed gear 31 is set ::o be e, amount of deviation between the -g ear 31 and the gear 32 is H1, as shown in Fig. 25 when the wlo le teeth are formed in accordance with the normal tcoth soecification if this angle is 6 is the same. However, when, there is provided the par` 32i which is formed to have a small tooth thickness according to the present embcdiment, the deviation amount becomes H2 and an absolute value of the deviation amount can be decreased. Fir this reason, with conventional teeth , as shown in Fig. 26, there is a possibility that the teeth may

'_nterfere with each other when the parallelism is deviated. However, i n the present embodiment, as shown in Fig. 27, the teeth are not caused to interfere with each other so as to generate no backlash. It should be noted that in 'Figs. 24 to 27, the angle 0 is drawn in exaggeration.

Also, as stated above, the teeth 31a and 32a of the 'Coth gears are meshed with each other only in the part :;2h which are formed in accordance with the regular gear soecif;cations. Thus, there is a possibility that the wi=dth of such meshed part becomes narrow and the surface c=essure of the teeth is increased, thereby making the s:rength unsatisfactory. However, in a normal use, a :oad appl_ed on each of the teeth 31a and 32a is small, so that the surface pressure of the teeth is not much increased. As a result, even if the width of the meshed cart becomes narrow, there is no possibility at all that .he str-ng-h of the mesh becomes unsatisfactory.

Further, when an excessive load input is received by :';e steering apparatus, like i n the case o- collision, t:ze tee:ih ;n the rema-ning par: 32i which are formed to r_.ve a credetermined small clearance with the teeth 31a c_ the -ixed gear 31 can be also meshed with the teeth @@a of the -ixed gear 31, so that a mesh with a satisfactory s:rength can be realized and an excessive load can be endured.

Further, it is no longer necessary to make the processing accuracy conspicuously high, unlike

conventional teeth , and to fix the gears 31, 32 by welding or by means of a bolt and a nut. As a result, =he manufacturing cost can be decreased, the number of ;.he constituent parts can be reduced, and further, the weight of the apparatus can be lightened.

Next, variations of different kinds are shown in Figs. 28 to 29E. Fig. 28 is a plan view of the movable gear ;the engagement member on the movable side), Fig. 29A is an enlarged view of the portion X in Fig. 28 according zo the above-described eighth embodiment, Fig. 29B is an enlarged view of the portion X in Fig. 28 according to a first variation of the eighth embodiment, Fig. 29C is @r. enlarged view of the portion X in Fig. 28 according to a second variation, Fig. 29D is an enlarged view of the por :ion X in Fig. 28 according to a third variation, and Fig. 29E is an enlarged view of the portion X in Fi g. 23 according to a fourth variation.

In =he above eighth embodiment, there is formed a step ce'tween the part 32h of the teeth formed in accordance r_th the regular gear specifi ca:ions and the part 32i of =e tee:h which are formed to have a small thickness.

on -he other hand, according to the first variation, as shown in Fig. 29B, part 132h which are formed in accordance with the regular gear specifications are c=ovided at the end or the teed 32a portion. However, par = 1'2h which are formed to be thin are formed to to tapered and the both parts '32h and 132i are formed

to be continuous.

According to the second variation, as shown in Fig. 29C, part 232h which are formed in accordance with the regular gear specifications are provided not at the end of the teeth 32a portion, unlike in the eighth embodiment, but provided substantially in a central portion of the teeth 32a portion.

According to the third variation, as shown in Fig. 29D, the teeth 332h which are formed in accordance with the regular gear specifications are provided substantially in a central portion of the engagement teeth 32a. However, the teeth 332h which are formed to be thin are formed to be tapered, and the both of the teeth 332h and 332i are formed to be continuous.

According to the fourth variation, as shown in Fig. 29E, part which are formed in accordance with the regular gear specifications are not clearly distinguished from part formed with a small tooth thickness, and the whole tooth portion is formed in a circular arc. As a result, there are substantially formed the part formed in accordance with the regular gear specifications and the part formed to have a small tooth thickness.

It should be noted that the present invention is not limited to the embodiments and variations described above, but various modification can be provided. For example, in any of the foregoing embodiments, the teeth 32a of the movable gear 32 (the engagement member on the movable

side) are provided with the parts 32i, 132i, 232i, 332i having the small tooth thickness. However, the teeth of the fixed gear 31 (the engagement member on the fixed side) may be provided with the part having a small thickness. Also, in any of the foregoing embodiments, the both gears 31 and 32 (the engagement member on the fixed side and the engagement member on the movable side) are circular gears. However, a gear in the present invention is not limited to these, but may take any of various forms such as a flat gear (rack).

As described above, according to the eighth embodiment of the present invention, part of the teeth at least in the width direction of the teeth of at least either one of the movable gear and the fixed gear are formed in accordance with the regular gear specifications, while the remaining part are formed to have a predetermined clearance with the other teeth. For this reason, in the normal use, if part of the teeth at least in the width of one of the engagement members formed in accordance with the regular gear specifications is meshed with the teeth of the other of the engagement members, a load applied on each of the teeth becomes small, so that if the parallelism between the teeth of the both members slightly deviates, a mesh with a satisfactory strength can be realized and no backlash is generated.

Also, when an excessive load input is received by the steering apparatus such as in the case of collision, the

remaining part of the teeth which are formed to have a predetermined clearance with the teeth of the other engagement member can be meshed with the teeth of the other engagement member, so that a mesh with a sufficient strength can be attained and an excessive load can be satisfactorily endured.

Further, it is no longer required to make the processing precision to be remarkably high, unlike in the conventional apparatus, and the engagement members are not required to be fixed by welding or a bolt and a nut, #,o as to reduce the manufacturing cost and the number of consti#:ueat parts. in addition, the weight of the apparatus can be lightened.

As described above, the tilt lock mechanism for causing the movable dear to mesh with the fixed gear to be locked compr'ses :he wedge .,ember which is removably inserted between :he reaction Force member and the back surface of the movable ::ear. This wedge member can be -formed to be thin. Also, -:ii s wedge member is covered w-4-.h the reaction force .-..ember in a state in which it is disposed at the lock cosition, so that it is possib'e to effectively prevent :he wedge member from hitting t`ie driver's knees or ;.he lock from being released thereby without specially c=ovid=ng, for example, a cove, that is, without -acreasina the number of consti went parts, and withcut -arrowing a space in the vici n_=v of the driver's knees.

Claims

CLAIMS 1. A tilt-adjustable steering apparatus comprising a first column member connected to a second column member to allow relative pivotal movement therebetween, said first column member having a movable gear which is engageable with a fixed gear of said second column member to lock said relative pivotal movement, said movable gear being pivotally mounted to said first column member about an axis such that said movable gear is allowed to move radially and transversely to said axis to prevent misalignment of the teeth of said movable gear and said fixed gear during engagement.
2. Apparatus as claimed in claim 1, wherein said movable gear is pivotally mounted on a pivot shaft that is received in bushing and the pivot shaft or a bore in which said bushing is received has an undulating surface arranged to permit said transverse movement.
3. Apparatus as claimed in claim 2, wherein said bushing is received in a through-bore in a body portion of said movable gear, said through-bore being provided with said undulating surface.

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4. Apparatus as claimed in claim 2 or 3, wherein said undulating surface comprises saw tooth projections.
5. Apparatus as claimed in any one of the preceding claims, wherein said fixed gear and a bracket of said second column member are an integral die casting.
6. Apparatus as claimed in any one of the preceding claims, further comprising a biasing member for urging said movable gear out of engagement with said fixed gear.
7. Apparatus as claimed in any one of the preceding claims, wherein said fixed gear is disposed on a periphery of the second column member.
8. Apparatus as claimed in any one of the preceding claims, wherein the second column member supports the fixed gear along substantially an entire length of said fixed gear.
9. Apparatus as claimed in any one of the preceding claims, further comprising a fixed member and a wedge member which is movable between release positions and locking positions in which locking positions the wedge member is positioned between the

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movable gear and the fixed member to lock said movable gear in engagement with said fixed gear.
10. Apparatus as claimed in claim 9, further comprising an operating member integral with said wedge member for moving said wedge member between said locking positions and said release positions.
11. Apparatus as claimed in claim 10, wherein said operating member is manually operable to move said wedge member.
12. Apparatus as claimed in claim 10 or 11, wherein said operating member is pivotably supported by said first column member.
13. Apparatus as claimed in any one of claims 9 to 12, wherein said fixed gear, said movable gear, said wedge member, and said fixed member are arranged such that surface portions thereof co-operating to lock said second column member with respect to said first column member when said wedge member is in a locking position overlie each other in a plane perpendicular to the pivot axis of said movable gear and disposed laterally intermediate of fixed gear.
14. Apparatus as claimed in any one of claims 9 to 13, wherein said fixed member is arranged to substantially cover said wedge member when the wedge

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member is in a locking position, whereby in use, a driver's knees are prevented from hitting the wedge member.
15. Apparatus as claimed in any one of claims 9 to 14, wherein said wedge member pivots between said locking positions and said release positions about an axis which is perpendicular to the respective axes of the column members and the axis about which said relative pivotal movement of said column members takes place.
16. Apparatus as claimed in claim 15, wherein said fixed member provides a planar support surface for the wedge member and said wedge member slides over said support surface when moving between said locking and release positions.
17. Apparatus as claimed in any one of the preceding claims, wherein the teeth of said fixed gear and the teeth of said movable gear are arranged such that when said movable gear is engaged with said fixed gear the respective teeth of said movable gear and said fixed gear are spaced apart along part of the length of the respective teeth.

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18. Apparatus as claimed in claim 1 wherein said fixed gear has a plurality of teeth extending laterally of said second column member; said movable gear is pivotable on a pin inserted through support portions defined by the first column member and extends parallel to the pivot axis of said first and second column members; said movable gear has a main body having a through-hole to receive said pin and a plurality of teeth capable of meshing with said teeth of said fixed gear; a bush is interposed between the outer peripheral surface of said pin and the inner peripheral surface of said through-hole; and special form portions into which a part of the bush is thrust when a force in a direction of twisting said movable gear main body is caused to work due to the mesh between the teeth of said fixed gear and the teeth of said movable gear are formed on one of the outer peripheral surface of said pin and the inner peripheral surface of said through- hole.

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19. Any of the tiltable steering apparatus substantially as herein described with reference to Figures 1 to 29E of the accompanying drawings.
20. A tilt adjusting-type steering apparatus wherein a lower steering shaft provided with a steering gear at the lower end thereof and an upper steering shaft provided with a steering wheel at the upper end thereof are coupled with each other by a universal joint, a lower column member for supporting said lower steering shaft to be rotatable is fixed to the body of a car, an upper column member for supporting said upper steering shaft to be rotatable is supported to be freely rockable in a vertical direction by a tilt shaft mounted on the lower column member to pass through the center of said universal joint, and said upper column member is locked with respect to said lower column member by means of a tilt lock mechanism, characterized in that: said tilt lock mechanism comprises a fixed gear mounted on one of said lower column member and said upper column member; a movable gear supported to be freely rockable by the other of said lower column member and said

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upper column member to be detachably engaged with said fixed gear; a reaction force member disposed in the vicinity of the back surface of said movable gear; and a wedge member to take a lock position at which it is inserted between said reaction force member and the back surface of same movable gear to cause said movable gear to mesh with said fixed gear and a release position at which it is extracted from the lock position to release said movable gear from said fixed gear.
21. A tilt adjusting-type steering apparatus according to claim 20, wherein said fixed gear is cast either in a lower bracket or an upper bracket.
22. A tilt adjusting-type steering apparatus according to claim 20, wherein at least a part of the teeth in the width direction out of at least one of the teeth of the movable gear and the teeth of the fixed gear are formed in accordance with the regular gear specifications, and the remaining teeth are formed to generate a predetermined clearance with the teeth of the other gear.

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23. A tilt adjusting-type steering apparatus according to claim 20, wherein said reaction force member is integrally formed with said other of said lower column member and said upper column member.
24. A tiltable steering apparatus comprising a first column member connected to a second column member to allow relative pivotal movement therebetween, said first column member having a movable gear which is engageable with a fixed gear of said second column member to lock said relative pivotal movement, and a wedge member which is movable to a position between said movable gear and a fixed member to lock said movable gear into engagement with said fixed gear.
25. A tiltable steering apparatus comprising a first column member connected to a second column member to allow relative pivotal movement therebetween, said first column member having a movable gear which is engageable with a fixed gear of said second column member to lock said relative pivotal movement, wherein the second column member is supported by a bracket and said bracket and said fixed gear are formed by die casting.

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26. A tiltable steering apparatus comprising a first column member connected to a second column member to allow relative pivotal movement therebetween, said first column member having a movable gear which is engageable with a fixed gear of said second column member to lock said relative pivotal movement, such that when said movable gear is engaged with said fixed gear the respective teeth of said movable gear and said fixed gear are spaced apart along part of the length of the respective teeth.