JP5061803B2 - Vehicle steering device and method of assembling the same - Google Patents

Description

  The present invention relates to a steering device for a center take-off type vehicle in which the axially inner ends of the left and right tie rods are connected to the center portion of the rack bar so that the left and right steering wheels are steered according to the lateral displacement of the rack bar. The present invention relates to a method for assembling an apparatus.

Conventionally, as shown in Patent Document 1 below, for example, a center take-off type vehicle steering device is known. This vehicle steering device is connected to a rack bar that extends in the left-right direction according to the steering operation of the steering wheel and a left-right steering wheel at the outer end in the axial direction. A pair of left and right tie rods that respectively steer left and right by swinging the steering wheel, and a pair of linkages that are fixed to the axial center of the rack bar and rotatably connect the inner ends of the pair of left and right tie rods. And a coupler that swings a pair of left and right tie rods in order to steer the left and right steering wheels to the left and right.
JP-A-11-321694

  In assembling the vehicle steering apparatus configured as described above, the tie rod is assembled to the coupler after the coupler is assembled to the rack bar. In this case, in a state where the coupler is assembled to the rack bar, the coupler is in a position close to the rack bar. On the other hand, the tie rod is a long member extending from the center in the vehicle left-right direction to the vicinity of the left and right wheels. Accordingly, when the tie rod is assembled to the coupler, the tie rod is provided with a rack bar housing that accommodates the rack bar, and a vehicle body mounting portion that protrudes toward the tie rod on the outer peripheral surface of the rack bar housing in order to attach the rack bar housing to the vehicle body. There is a problem that it is easy to interfere with peripheral parts such as a so-called gear mount and the tie rod is not easily assembled. In particular, when the tie rod is assembled to the coupler, the outer surface of the tie rod tends to collide with the vehicle body mounting portion provided on the rack bar housing. When the outer surface of the tie rod collides with the vehicle body mounting portion, there is a problem that the rust preventive portion such as plating and coating applied to the outer peripheral surface of the tie rod is damaged, and the rust preventive effect of the rust preventive portion decreases.

  The present invention has been made in order to cope with the above-described problems. The object of the present invention is to improve the assembling property of the tie rod to the coupler and to avoid the collision between the tie rod and the vehicle body mounting portion during the assembling operation. An object of the present invention is to provide a vehicle steering apparatus.

In order to achieve the above object, the present invention is characterized by a rack bar that extends in the left-right direction in the axial direction and is displaced in the left-right direction in accordance with the steering operation of the steering handle, and the left and right steering wheels at the outer ends in the axial direction. Are connected to each other, and a pair of left and right tie rods that respectively steer left and right by swinging the left and right steering wheels, and a rack bar and a pair of left and right tie rods are connected, and left and right steering is performed according to the left and right displacement of the rack bar. A steering apparatus for a vehicle including a coupler that swings a pair of left and right tie rods to steer a wheel from side to side, and a bracket that is assembled and fixed at the center position in the axial direction of the rack bar; , a pair from the outside of the left and right directions on the bracket as a pair of support members fixed to screwed inwardly, and axially inner end is supported rotatably Ri pair of connecting rods assembled respectively to the support member Tona, constituted by a pair of connecting assemblies that make up each ball joint mechanism, the axis of the pair of left and right tie rods to axially outer ends of a pair of connecting rods A heat insulator that joins the inner ends in the direction and is fixed to the bracket to cut off heat to the coupler, and is an upper plate portion and a lower plate portion that are vertically connected to each other and are integrally connected by the connecting portion. And a heat insulator in which the area of the upper plate portion is smaller than the area of the lower plate portion .

In this case, the pair of connecting rods are configured to be relatively short and are at least shorter than the pair of tie rods. Further, it left and right pair of tie rods, for example, is screwed toward the inside from the outside of the left and right directions in a pair of connecting rods. When screwing the tie rod to the connecting rod, a male thread is formed at the outer end of the connecting rod in the axial direction, and a female thread is formed at the inner end of the tie rod in the axial direction. Good to join. Conversely, a female thread may be formed at the axially outer end of the connecting rod, and a male thread may be formed at the axially inner end of the tie rod, and the male thread of the tie rod may be screwed to the female thread of the connecting rod. .

In assembling the steering apparatus for a vehicle configured as described above, the bracket coupler assembled La Kkuba, each of the support members of the pair of coupling assembly is assembled, respectively. Since the coupling assembly is in a state in which the pair of coupling rods are rotatably assembled to the pair of support members at their axially inner ends, the pair of coupling rods are rack bars at their axially inner ends. And rotatably supported by the coupler. Therefore, in this state, the axially outer end of the connecting rod can be located at a position away from the rack bar. In this state, if the axially inner ends of the pair of tie rods are assembled to the axially outer ends of the pair of connecting rods, the tie rod can accommodate the rack bar even if the tie rod is a long member. It is difficult to interfere with peripheral parts such as a rack bar housing and a vehicle body mounting portion (so-called gear mount) provided on the outer peripheral surface of the rack bar housing so as to protrude to the tie rod side in order to attach the rack bar housing to the vehicle body. As a result, according to the vehicle steering apparatus configured as described above, the steering apparatus can be easily assembled in a short time. In particular, when the tie rod is assembled to the coupler, it can be avoided that the outer surface of the tie rod collides with the vehicle body mounting portion provided on the rack bar housing, and the rust prevention such as plating and coating applied to the outer peripheral surface of the tie rod. It is also possible to avoid damaging the processing part.

Further, since the heat insulator cuts off the heat to the coupler, the ball joint mechanism is protected from the heat generated in the vehicle when the steering device is assembled to the vehicle. In particular, since the area of the upper plate portion is smaller than the area of the lower plate portion, the heat in the heat insulator easily escapes upward, and the temperature rise in the heat insulator is favorably suppressed.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an overall external view of the vehicle steering apparatus according to the embodiment. 2 is an enlarged cross-sectional view of a portion surrounded by a two-dot chain line in FIG. In the present specification, the front-rear direction means the front-rear direction of the vehicle, and the left-right direction means the left-right direction of the vehicle.

  The vehicle steering apparatus includes a steering handle 11, a rack bar 21, a pair of left and right tie rods 31, 32, a coupler 40, and a heat insulator 61. The steering handle 11 is steered by the driver to steer the left and right front wheels FW1 and FW2 as steering wheels. The rack bar 21 is displaced in the left-right direction of the vehicle according to the steering operation of the steering handle 11. The tie rods 31 and 32 swing according to the displacement of the rack bar 21 in the left-right direction and steer the left and right front wheels FW1, FW2 to the left and right. The coupler 40 connects the rack bar 21 and the tie rods 31 and 32, and swings the tie rods 31 and 32 according to the displacement of the rack bar 21 in the left-right direction. The heat insulator 61 covers the coupler 40 and blocks radiant heat from the heat source to the coupler 40.

  The rack bar 21 is formed in a long shape with a metal material, and has rack teeth in a part thereof. The rack bar 21 is incorporated in a rack bar housing 22 formed of a metal material in a cylindrical shape so that the rack bar housing 22 has the same axial direction as that of the rack bar housing 22 and can be displaced in the axial direction. The rack teeth of the rack bar 21 mesh with a pinion gear provided at the lower end portion of the steering shaft 13 in the gear box 12 assembled to the rack bar housing 22. A steering handle 11 is assembled to the upper end of the steering shaft 13. When the steering handle 11 is rotated, the steering shaft 13 rotates about the axis, and the rack bar 21 is displaced in the left-right direction. On the central front side of the rack bar 21, circular recesses 21a and 21b are respectively formed at left and right symmetrical positions with the center position in the left and right direction of the vehicle sandwiched between the rack bar 21 and the neutral position. Further, on the front side of the center of the rack bar 21, bottomed screw holes 21 c and 21 d are formed in which female threads are formed on the inner peripheral surface from the center of the bottom surface of the recesses 21 a and 21 b toward the rear.

  Cylindrical vehicle body mounting portions (gear mounts) 22a and 22b that come to the front side position in the assembled state of the vehicle body are integrally provided on the outer periphery of both end portions of the rack bar housing 22. Mount bushes 23 and 24 are press-fitted into the vehicle body attachment portions 22a and 22b. The rack bar housing 22 is fixed to a vehicle body (not shown) with bolts (not shown) penetrating the mount bushes 23 and 24 in a state of extending in the left-right direction of the vehicle. On the front side of the center portion of the rack bar housing 22, a horizontally long rectangular opening 22 c is provided in order to allow the rack bar 21 and the coupler 40 to be integrally displaced in the left-right direction. The lateral length of the opening 22c is set slightly longer than the maximum displacement amount of the rack bar 21 in the left-right direction.

  The rack bar housing 22 is covered with dust boots 25 except for the left and right ends. The dust boot 25 is integrally formed of a rubber material, and has a central portion 25a formed thick, and has thin bellows portions 25b and 25c on both sides of the central portion 25a. The central portion 25a is formed in a cylindrical shape and has a concave portion 25a1 that forms a plane perpendicular to the front side portion thereof. The recess 25a1 is provided with through holes 25a2 and 25a3 at positions where the screw holes 21c and 21d face each other when the rack bar 21 is in a neutral state. Both end portions of the dust boot 25 are fixed on the outer periphery of the rack bar housing 22. The center portion 25a of the dust boot 25 is assembled to the rack bar 21 by a coupler 40, as will be described in detail later. Accordingly, the central portion 25a of the dust boot 25 is displaced in the left-right direction with the expansion and contraction of the bellows portions 25b, 25c according to the displacement of the rack bar 21 in the left-right direction.

  The tie rods 31 and 32 respectively connect the left and right front wheels FW1 and FW2 so as to be steerable by swinging through knuckle arms (not shown) assembled to the connecting members 33 and 34 at the outer ends. The inner ends of the tie rods 31 and 32 are connected to the coupler 40 so as to be displaced in the left-right direction according to the displacement of the coupler 40 in the left-right direction.

  The coupler 40 includes a bracket 41 and a pair of left and right ball joint mechanisms 50A and 50B. As shown in FIGS. 5A to 5E, the bracket 41 includes a main body portion 41a and attachment portions 41b and 41c, and is formed in a T shape in plan view by integrally molding a metal material. FIG. 5A is a front view of the bracket 41, that is, a view of the bracket 41 as seen from the front in an assembled state to the vehicle. FIG. 5B is a plan view of the bracket 41, and FIG. 5C is a side view of the bracket 41. 5D is a cross-sectional view of the bracket 41 taken along line 5D-5D of FIG. 5A, and FIG. 5E is a cross-sectional view of the bracket 41 taken along line 5E-5E of FIG. 5A.

  The main body 41a has the same width in the horizontal direction from the front end to the vicinity of the rear end, and is formed in a shape such that the width in the horizontal direction gradually increases toward the rear at the rear end. Further, the main body 41a has a U-shaped (that is, arcuate) vertically symmetric outer shape at the front portion and a straight vertical symmetric outer shape at the rear portion when viewed from the lateral direction. The upper and lower surfaces of the rear part form a flat surface, and the upper and lower surfaces of the rear part constitute seat surfaces 41 a 1 and 41 a 2 when the heat insulator 61 is assembled to the bracket 41. The rear end portion of the main body 41a has a step that protrudes upward and downward from the seating surfaces 41a1 and 41a2, respectively, and extends linearly in the lateral direction at the rear ends of the seating surfaces 41a1 and 41a2 when viewed from the lateral direction. Protrusions 41a3 and 41a4 to be formed are provided. The width in the front-rear direction of these protrusions 41a3, 41a4 is smaller than the length in the front-rear direction of the seat surfaces 41a1, 41a2. A screw hole 41a5 is formed in the front portion of the main body 41a. The screw hole 41a5 penetrates in the lateral direction and has an internal thread formed on the inner peripheral surface. Bottomed screw holes 41a6 and 41a7 in which female threads are formed on the inner peripheral surface from the seating surfaces 41a1 and 41a2 to the inside are provided in the intermediate part of the main body 41a.

  The attachment parts 41b and 41c are respectively extended in the left-right direction from the rear end parts (corresponding to the front and rear positions of the projecting parts 41a3 and 41a4) of the main body part 41a. The width in the front-rear direction of the attachment portions 41b, 41c is equal to the width in the front-rear direction of the protrusions 41a3, 41a4. The attachment portions 41b and 41c have U-shaped (that is, arc-shaped) left and right symmetrical outer shapes when viewed from the front. Further, the mounting portions 41b and 41c are provided with circular holes 41b1 and 41c1 penetrating in the front-rear direction.

  The bracket 41 is fixed to the rack bar 21 using a pair of bolts 42 and 43 at the attachment portions 41b and 41c. The bolts 42 and 43 pass through the holes 41 b 1 and 41 c 1 of the mounting portions 41 b and 41 c and the through holes 25 a 2 and 25 a 3 of the dust boot 25 and are screwed to the screw holes 21 c and 21 d of the rack bar 21. In order to firmly fix the connector 41 to the exact positions of the rack bar 21 and the dust boot 25, metal collars 44 and 45 and a resin support member 46 are assembled on the outer periphery of the bolts 42 and 43. Yes. The collars 44 and 45 are formed in a stepped cylindrical shape, the rear end portion is fitted into the recesses 21a and 21b of the rack bar 21, and the front end portion is fitted into the through holes 25a2 and 25a3 of the dust boot 25, Bolts 42 and 43 are penetrated. The support member 46 is integrally formed of a resin material in an oval shape and has a pair of through holes. Bolts 42 and 43 and collars 44 and 45 are passed through the through holes. The support member 46 is interposed between the stepped portions of the collars 44 and 45 and the concave portion 25a1 of the dust boot 25 so that the concave portion 25a1 is sandwiched between the coupler 40.

  The ball joint mechanisms 50A and 50B include metal support members 51 and 52 and metal connecting rods 53 and 54. The support members 51 and 52 are fixed to the bracket 41 by screwing male screw portions 51 a and 52 a provided on the inner side thereof into screw holes 41 a 5 of the bracket 41 from the outside. The support members 51 and 52 rotatably support the spherical ball portions 53a and 54a provided at the inner ends of the connecting rods 53 and 54 through the resin seats 55 and 56 at the ball seat portions 51b and 52b. is doing. The ball seats 51b and 52b are covered with rubber dust boots 57 and 58. Male threaded portions 53b, 54b provided on the outer portions of the connecting rods 53, 54 are screwed to female threaded portions 31a, 32a provided on the inner peripheral surfaces of the tie rods 31, 32, respectively. The tie rods 31 and 32 are firmly fixed to the connecting rods 53 and 54 by the lock nuts 59 and 60. FIG. 3 shows the connection state of the support members 51 and 52, the connecting rods 53 and 54, and the tie rods 31 and 32 in a partially cutaway view. The ball joint mechanisms 50A and 50B including the support members 51 and 52 and the connecting rods 53 and 54 constitute the connecting assembly of the present invention.

  The heat insulator 61 covers the connector 40 from the front side, and protects the connector 40 by blocking radiant heat from the engine and its accessory parts located at the front lower side of the connector 40 to the connector 40. In particular, the heat insulator 61 protects the ball joint mechanisms 50A and 50B by blocking the radiation heat to the grease and the like sealed in the seats 55 and 56 and the ball seats 51b and 52b in the coupler 40. The heat insulator 61 is shown in FIGS. 6A to 6E. FIG. 6A is a front view of the heat insulator 61, that is, a view of the heat insulator 61 as seen from the front in an assembled state to the vehicle. 6B is a plan view of the heat insulator 61, and FIG. 6C is a side view of the heat insulator 61. FIG. 6D is a partially enlarged view of the heat insulator 61 in the portion indicated by the arrow 6D in FIG. 6C. FIG. 6E is a partially enlarged view of the heat insulator 61 at the portion indicated by the arrow 6E in FIG. 6C.

  The heat insulator 61 is formed by bending a metal plate (for example, a metal plate made of iron), and is integrally connected by a connecting portion 61a located on the front side in an assembled state to the connector 40. It has the board part 61b and the lower board part 61c. The upper plate portion 61b and the lower plate portion 61c face each other up and down, and together with the connecting portion 61a, form a space SP that is open to the rear with a U-shaped longitudinal section. The space SP is also open on the left and right sides. The lower plate portion 61c is formed in a square shape and is cut out in a small arc shape in a symmetrical manner at the left and right front end portions. The upper plate portion 61b is also formed in the same rectangular shape as the lower plate portion 61c, and is relatively large notched obliquely forward from the center portion in a bilaterally symmetrical manner. The area of the upper plate portion 61b is set smaller than the area of the lower plate portion 61c. In other words, the area where the upper plate portion 61b covers the space SP is smaller than the area where the lower plate portion 61c covers the space SP by the area cut out obliquely forward of the upper plate portion 61b. Thereby, the heat in the heat insulator 61 easily escapes upward, and the temperature rise in the heat insulator 61 is satisfactorily suppressed. Moreover, the connection part 61a, the upper board part 61b, and the lower board part 61c are formed so that the center part of the left-right direction may be depressed rather than an outer part.

  Flat portions 61b1 and 61c1 having a predetermined width are formed at the center positions of the upper plate portion 61b and the lower plate portion 61c from the position near the front end toward the rear. The rear end portions of the flat surface portions 61b1 and 61c1 protrude in a square shape from the rear end surfaces of the upper plate portion 61b and the lower plate portion 61c on the outer side, thereby forming the protruding portions 61b2 and 61c2. Circular through-holes 61b3 and 61c3 having the same diameter as the screw holes 41a6 and 41a7 provided in the bracket 41 are formed at the center in the left-right direction in front of the protrusions 61b2 and 61c2. The length from the rearmost position of the inlets of these through holes 61b3 and 61c3 to the front end of the projecting portions 61b2 and 61c2 is from the rearmost position of the inlets of the screw holes 41a6 and 41a7 of the bracket 41 to the seating surfaces 41a1 and 41a2. It is equal to the length to the level | step difference of provided protrusion part 41a3 and 41a4. This is because when the heat insulator 61 is assembled to the bracket 41, the front end surfaces of the protrusions 61 b 2 and 61 c 2 of the heat insulator 61 are brought into contact with the stepped surfaces of the protrusions 41 a 3 and 41 a 4 of the bracket 41. This is for positioning. Regarding the heat insulator 61, it is preferable to process the end surfaces of the protruding portions 61b2 and 61c2 with high precision by press punching. In addition, regarding the protruding portions 41a3 and 41a4 of the bracket 41, the step surfaces of the protruding portions 41a3 and 41a4 may be molded with high accuracy by machining such as cutting.

  The heat insulator 61 configured in this manner is fixed to the main body 41a of the bracket 41 as shown in FIGS. 4A and 4B. 4A is a plan view showing a state in which only the bracket 41 and the heat insulator 61 are taken out from FIGS. 1 and 2 and the heat insulator 61 is assembled to the bracket 41. FIG. 4B is a cross-sectional view taken along line 4B-4B in FIG. 4A.

  The heat insulator 61 brings the lower surface of the flat surface portion 61b1 of the upper plate portion 61b into close contact with the seating surface 41a1 of the bracket 41, and brings the lower surface of the flat surface portion 61c1 of the lower plate portion 61c into close contact with the seating surface 41a2 of the bracket 41. The rear end surface of the protruding portion 61b2 of the upper plate portion 61b of the heat insulator 61 is brought into contact with the stepped surface of the protruding portion 41a3 of the bracket 41, and the rear end surface of the protruding portion 61c2 of the lower plate portion 61c of the heat insulator 61 is bracketed. It is made to contact | abut to the level | step difference surface of 41 protrusion part 41a4. Then, the bolts 62 and 63 are screwed into the screw holes 41a6 and 41a7 of the bracket 41 through the through holes 61b3 and 61c3 of the heat insulator 61. Thereby, the heat insulator 61 is fixed to the bracket 41.

  The assembly of the steering device configured as described above will be described. The rack bar 21 is accommodated in the rack bar housing 22, and the mount bushes 23 and 24 and the dust boot 25 are assembled to the rack bar housing 22. In this case, the collars 44 and 45 and the support member 46 are also assembled to the rack bar 21. In this state, the bracket 41 of the coupler 40 is fixed to the rack bar 21 using the bolts 42 and 43 (bracket assembly process). On the other hand, the connecting rods 53 and 54 are assembled to the supporting members 51 and 52 in a state where the ball portions 53a and 54a of the connecting rods 53 and 54 are rotatably supported by the ball seats 51b and 52b of the supporting members 51 and 52, respectively. Then, ball joint mechanisms (connection assemblies) 50A and 50B are assembled (connection assembly assembly process). In this case, before assembling the ball joint mechanisms 50A and 50B, the cylindrical seats 55 and 56 are incorporated into the cylindrical ball seat portions 51b and 52b, and the ball portions 53a and 54a are incorporated into the seats 55 and 56, respectively. , The ball seats 51b and 52b are caulked, and then the dust boots 57 and 58 are assembled to assemble the ball joint mechanisms 50A and 50B.

  Next, the support members 51 and 51 of the ball joint mechanisms 50A and 50B are respectively assembled to the bracket 41 assembled to the rack bar 21 (connection assembly assembling step). In this connecting assembly assembling process, the male screw portions 51a and 51b of the support member 51 are screwed into the screw holes 41a5 of the bracket 41 from the outside in the left-right direction to the inside, and the ball joint mechanisms 50A and 50B are fixed to the bracket 41. To do. Then, the inner ends in the axial direction of the tie rods 31 and 32 are assembled to the outer ends in the axial direction of the connecting rods 53 and 54 of the ball joint mechanisms 50A and 50B, respectively (tie rod assembling step). In this tie rod assembling process, the ball portions 53a and 54a of the connecting rods 53 and 54 are rotated to slightly tilt the connecting rods 53 and 54 forward (in the direction opposite to the rack bar 21). Next, the lock nuts 59 and 60 are assembled to the male screw portions 53b and 54b of the connecting rods 53 and 54, the female screw portions 31a and 32a of the tie rods 31 and 32 are screwed in, and finally the lock nuts 59 and 60 are tightened. The tie rods 31 and 32 are firmly fixed to the connecting rods 53 and 54. Then, the heat insulator 61 is fixed to the bracket 41 as described above. Further, the connecting members 33 and 34 are assembled to the outer end portions of the tie rods 31 and 32. Note that the heat insulator 61 and the connecting members 33 and 34 may be assembled before the tie rods 31 and 32 are assembled to the connecting rods 53 and 54.

  The steering assembly is assembled by such a stroke. In assembling the steering assembly to the vehicle body, the bolts are passed through the mounting bushes 23 and 24 assembled to the vehicle body attachment portions 22a and 22b and fixed to the vehicle body. Thereafter, the steering shaft 13 and the steering handle 11 are assembled to the steering assembly, and the steering handle 11 is connected to the rack bar 21. Further, the knuckle arm and the left and right front wheels FW1, FW2 are assembled to the connecting members 33, 34 assembled to the outer ends of the tie rods 31, 32, respectively.

  In such an assembly method, the support members 51 and 52 of the ball joint mechanisms (connection assemblies) 50A and 50B are assembled to the bracket 41 of the coupler 40 assembled to the rack bar. Since the ball joint mechanisms (connection assemblies) 50A and 50B are in a state in which the connection rods 53 and 54 are rotatably assembled to the support members 51 and 52 at their inner ends in the axial direction, The rack bar 21 and the coupler 40 are rotatably supported at their inner ends in the axial direction. Therefore, in this state, the outer ends in the axial direction of the connecting rods 53 and 54 can be positioned away from the rack bar 21 and the rack bar housing 22. In this state, since the inner ends in the axial direction of the tie rods 31 and 32 are assembled to the outer ends in the axial direction of the connecting rods 53 and 54, even if the tie rods 31 and 32 are long members, the tie rod 31 , 32 are less likely to interfere with the rack bar housing 22 and its peripheral components, particularly the vehicle body mounting portions 22a, 22b. As a result, according to the assembling method, the steering device can be easily assembled in a short time. In particular, when the tie rods 31 and 32 are assembled to the coupler 40 (ball joint mechanisms 50A and 50B), the outer surfaces of the tie rods 31 and 32 are caused to collide with the vehicle body mounting portions 22a and 22b of the rack bar housing 22. It is possible to avoid this, and it is also possible to avoid damaging the rust-proof treated parts such as plating and coating applied to the outer peripheral surfaces of the tie rods 31 and 32.

  The operation of the embodiment configured as described above will be described. When the driver rotates the steering handle 11 left and right, the rotation of the steering handle 11 is transmitted to the rack bar 21 via the steering shaft 13, and the rack bar 21 is displaced in the left-right direction. Due to the horizontal displacement of the rack bar 21, the bracket 41 and the support members 51 and 52 are also displaced to the left and right integrally with the rack bar 21. The tie rods 31 and 32 swing integrally with the connecting rods 53 and 54 while the ball portions 53a and 54a of the connecting rods 53 and 54 rotate due to the displacement of the support members 51 and 52 in the left and right direction, and the left and right front wheels FW1. , FW2 is steered. Therefore, the left and right front wheels FW1 and FW2 are steered by the turning operation of the steering handle 11.

  Further, the heat insulator 61 blocks radiant heat from the engine and its accessory parts to the coupler 40, in particular, the seats 55 and 56 of the ball joint mechanisms 50A and 50B, the ball seat portions 51b and 52b, and the ball portions 53a and 54a. Accordingly, since the grease in the seats 55 and 56 and the ball seats 51b and 52b does not rise to a high temperature, the seats 55 and 56 and the grease are not easily deformed and deteriorated by heat, and the ball joint mechanisms 50A and 50B Good operation is maintained.

  Furthermore, the present invention is not limited to the above-described embodiment, and various modifications can be employed within the scope of the present invention.

  In the above embodiment, as shown in FIG. 3, male screw portions 53 b and 54 b are formed on the shaft portions of the connecting rods 53 and 54 of the ball joint mechanisms (connecting assemblies) 50 </ b> A and 50 </ b> B, and the axial direction of the tie rods 31 and 32. Female threaded portions 31a and 32a are formed at the inner ends, and the female threaded portions 31a and 32a of the tie rods 31 and 32 are screwed to the male threaded portions 53b and 54b of the connecting rods 53 and 54, respectively. However, instead of this, as shown in FIG. 7, the shaft portions of the connecting rods 53 and 54 are formed in a cylindrical shape, the female screw portions 53c and 54c are formed on the inner peripheral surface thereof, and the tie rods 31 and 32 The male threaded portions 31b and 32b may be formed at the axially inner end, and the male threaded portions 31b and 32b of the tie rods 31 and 32 may be screwed to the female threaded portions 53c and 54c of the connecting rods 53 and 54. In this case, the male threaded portions 31b and 32b of the tie rods 31 and 32 are screwed to the female threaded portions 53c and 54c of the connecting rods 53 and 54 and the lock nuts 59 and 60 from the outer side in the left-right direction to the inner side. The inner ends of the tie rods 31, 32 are firmly fixed to the outer ends of the connecting rods 53, 54 by the lock nuts 59, 60.

  Also in this modified example, in the process of connecting the tie rods 31 and 32 to the connecting rods 53 and 54, the outer ends in the axial direction of the connecting rods 53 and 54 are positioned away from the rack bar 21 and the rack bar housing 22. Can do. Therefore, as described in the above embodiment, the steering device can be easily assembled in a short time, and the outer surfaces of the tie rods 31 and 32 can collide with the vehicle body mounting portions 22a and 22b of the rack bar housing 22. Can be avoided.

1 is an overall external view of a vehicle steering apparatus according to an embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view of a portion surrounded by a two-dot chain line in FIG. It is a fragmentary broken view which shows the assembly | attachment state to the connecting rod of a tie rod. It is a top view which shows the assembly | attachment state to the bracket of a heat insulator. It is sectional drawing seen along the 4B-4B line | wire of FIG. 4A. It is the front view of a bracket, ie, the figure which looked at the bracket from the front in the assembly | attachment state to a vehicle. It is a top view of a bracket. It is a side view of a bracket. It is sectional drawing of the bracket seen along the 5D-5D line | wire of FIG. 5A. It is sectional drawing of the bracket seen along the 5E-5E line | wire of FIG. 5A. It is the front view of a heat insulator, ie, the figure which looked at the heat insulator from the front in the state of attachment to vehicles. It is a top view of a heat insulator. It is a side view of a heat insulator. It is the elements on larger scale of the heat insulator of the part shown by arrow 6D of Drawing 6C. It is the elements on larger scale of the heat insulator of the part shown by arrow 6E of Drawing 6C. It is a fragmentary broken view which shows the assembly | attachment state to the connection rod of a tie rod concerning a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Steering handle, 13 ... Steering shaft, 21 ... Rack bar, 22 ... Rack bar housing, 25 ... Dust boot, 31, 32 ... Tie rod, 40 ... Coupler, 41 ... Bracket, 50A, 50B ... Ball joint mechanism, 51 , 52 ... Support member, 53, 54 ... Connecting rod, 55, 56 ... Sheet, 61 ... Heat insulator

Claims (2)

A rack bar extending in the left-right direction with the axis line direction displaced in the left-right direction according to the steering operation of the steering wheel;
A pair of left and right tie rods that respectively connect the left and right steered wheels at the outer ends in the axial direction and steer the left and right steered wheels left and right by swinging;
A coupler that connects the rack bar and the pair of left and right tie rods, and swings the pair of left and right tie rods in order to steer the left and right steering wheels to the left and right according to a displacement in the left and right direction of the rack bar; A vehicle steering apparatus comprising:
The coupler,
A bracket assembled and fixed at the center position in the axial direction of the rack bar;
A pair of support members fixed to the bracket by screwing from the outside in the left-right direction to the inside , respectively , and the pair of support members are assembled so that the inner ends in the axial direction are rotatably supported. Ri pair of connecting rods Tona, constituted by a pair of connecting assemblies that make up each ball joint mechanism,
The pair of connecting rods of the pair to the axially outer end of the axially inner end portion of the tie rod attached respectively, further
A heat insulator that is fixed to the bracket and blocks heat to the coupler, and has an upper plate portion and a lower plate portion that are integrally connected to each other by a connecting portion and are opposed to each other, and the upper plate portion A vehicle steering apparatus characterized in that a heat insulator having a smaller area than the area of the lower plate portion is provided . The pair of left and right tie rods, steering system for a vehicle according from the outside of the left and right directions in the pair of connecting rods to claim 1 which is screwed toward the inside.

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