JP2012106650A - Rack-and-pinion steering gear unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rack-and-pinion steering gear unit having such a structure that the outer circumferential surface of a pressing block can be prevented from colliding vigorously with the inner peripheral surface of a cylinder under high surface pressure to enhance durability.SOLUTION: In the pressing block 21a, the outside diameter d of a useless thickness part 27a existing at the tip side of a locking concave groove 25 for locking an elastic ring 26 is made smaller than the outside diameter D of an intermediate part or a base end (d<D). If necessary, the outer circumferential surface of the idle thick part 27a is formed to have a tapered shape. Even if the pressing block 21a is oscillated and displaced in the cylinder 20 when power is transmitted, the outer circumferential edge of the tip of the pressing block 21a does not collide vigorously with the inner peripheral surface of the cylinder 20.

Description

  The present invention relates to an improvement of a rack and pinion type steering gear unit that constitutes a steering device for giving a steering angle to a steering wheel of an automobile. Specifically, it is intended to realize a structure capable of reducing the manufacturing cost while ensuring the sealing performance of the pinion shaft mounting portion.

   A steering device including a rack and pinion type steering gear unit that uses a rack and pinion as a mechanism for converting a rotational motion input from a steering wheel into a linear motion for giving a steering angle is disclosed in, for example, Patent Documents 1 to 3. 5 and the like. In addition, the rack and pinion type steering gear unit can be configured to be small and light, and since it has high rigidity and a good steering feeling, it is actually widely used. 5 to 7 show a structure described in Patent Document 4 as an example of a steering apparatus incorporating such a rack and pinion type steering gear unit. In this steering device, the movement of the steering shaft 2 that rotates in accordance with the operation of the steering wheel 1 is transmitted to the pinion shaft 6 that is the input shaft of the steering gear unit 5 through the universal joints 3 and 3 and the intermediate shaft 4. To do. In addition, the up-down direction of the said FIGS. 6-7 does not necessarily correspond with the up-down direction in use condition. The vertical direction is appropriately selected depending on the state of assembly in the vehicle, and in general, the pinion shaft 6 is installed in an inclined state with respect to the vertical direction.

  In any case, the steering gear unit 5 is formed by meshing the pinion teeth 7 provided on a part of the pinion shaft 6 in the axial direction with the rack teeth 9 provided on the front surface of the rack shaft 8. Of these, the rack teeth 9 having a twist angle θ as schematically shown in FIG. 8 are used, and a helical gear having a similar twist angle is also used for the pinion teeth 7 correspondingly. ing. Each of the pinion shaft 6 and the rack shaft 8 is housed in a casing 10. The casing 10 includes a main storage portion 11 and a sub storage portion 12 each having a cylindrical shape. Of these, the main storage portion 11 is open at both ends. Moreover, this sub-accommodating part 12 is provided in a part of the main accommodating part 11, and one end is opened. The central axis of the main storage portion 11 and the central axis of the sub storage portion 12 are in a twisted positional relationship with each other. The rack shaft 8 is inserted through the main storage portion 11 of the rack shaft 8 so as to be axially displaceable, and both end portions protrude from the main storage portion 11. Also, a pair of rack guides (sliding bearings) 13 and 13 supported on both ends of the inner peripheral surface of the main storage portion 11 are brought into sliding contact with the outer peripheral surface of the rack shaft 8 so that the rack shaft 8 The main storage portion 11 can be displaced in the axial direction without rattling. And the base end part of the tie rods 15 and 15 is couple | bonded with the both ends of this rack shaft 8 via the spherical couplings 14 and 14, respectively. The tip portions of both tie rods 15 and 15 are respectively connected to the tip portions of knuckle arms (not shown) by pivots. The rack shaft 8 does not rotate around its central axis due to the engagement of the pinion teeth 7 and the rack teeth 9.

  The pinion shaft 6 supports the tip half of the pinion teeth 7 in the sub-accommodating portion 12 so that it can only rotate. For this purpose, the tip end portion of the pinion shaft 6 is supported by the radial needle bearing 16 at the back end portion of the auxiliary storage portion 12. Further, a radial load and a thrust load are supported by a single-row ball bearing 17 such as a deep groove type, a three-point contact type, or a four-point contact type at an intermediate portion of the pinion shaft 6 near the opening of the auxiliary storage portion 12. It supports as possible (rotates while preventing axial displacement). In order to support the ball bearing 17 at a predetermined position of the casing 10, a holding screw cylinder 18 is screwed to the casing 10, and an inner circumferential surface of the holding screw cylinder 18 and an outer circumferential surface of the pinion shaft 6 are arranged. The gap between them is closed by the seal ring 19.

  A cylinder portion 20 is provided on the opposite side of the auxiliary storage portion 12 with respect to the diameter direction of the main storage portion 11, and a pressing block 21 is fitted in the cylinder portion 20. An elastic member such as a spring 23 is provided between the cover 22 screwed into the opening of the cylinder portion 20 and the pressing block 21 to press the pressing block 21 toward the rack shaft 8. . As a result, the rack shaft 8 is elastically pressed toward the pinion shaft 6 to eliminate backlash of the meshing portion between the pinion teeth 7 and the rack teeth 9. Furthermore, the meshing state of the meshing portion is properly maintained regardless of the force in the direction away from the pinion shaft 6 applied to the rack shaft 8 with the transmission of power at the meshing portion between the teeth 7 and 9. I am trying to do it. Of the both end surfaces in the axial direction of the pressing block 21, the inner end surface on the side pressing the rack shaft 8 is a partially cylindrical concave surface according to the shape of the back surface of the rack shaft 8. On the other hand, the outer end surface of the pressing block 21 is formed with a recess 24 in the center portion to serve as a spring seat for contacting one end portion of the spring 23, and the weight of the pressing block 21 is reduced. I am trying.

  Further, a locking groove 25 is formed over the entire periphery of the outer peripheral surface of the pressing block 21 (a portion close to the rack shaft 8), and an elastic ring is formed in the locking groove 25. 26 is locked. The elastic ring 26 has a circular cross-sectional shape in a free state like an O-ring, and the outer diameter related to the cross-sectional shape is larger than the depth of the locking groove 25 in the free state. Such an elastic ring 26 is elastically compressed between the bottom surface of the locking groove 25 and the inner peripheral surface of the cylinder portion 20. And while preventing that the press block 21 rattles in this cylinder part 20, mud water etc. in the said casing 10 through the clearance gap between the internal peripheral surface of these cylinder parts 20, and the outer peripheral surface of the press block 21 Prevent foreign material from entering. Note that a minute gap is interposed between the outer peripheral surface of the pressing block 21 and the inner peripheral surface of the cylinder portion 20 to allow the pressing block 21 to be displaced in the axial direction. In the case of the conventional structure, the outer diameter of the pressing block 21 is set to the both sides of the locking groove 25, that is, the distal end portion on the lid body 22 side, and the intermediate portion to the proximal end portion on the rack shaft 8 side, They were the same as each other.

  When a steering angle is given to the left and right front wheels by the steering device incorporating the steering gear unit 5 as described above, the pinion shaft 6 is rotated by operating the steering wheel 1. Then, the rack shaft 8 is displaced in the axial direction based on the meshing of the pinion teeth 7 and the rack teeth 9. Then, the tie rods 14 and 14 coupled to both ends of the rack shaft 8 are pushed and pulled to give a desired rudder angle to the front wheels.

  In the case of the conventional steering gear unit 5 as described above, the rotational direction of the pinion shaft 6 is reversed when the torsion angle θ is provided in the pinion teeth 7 and the rack teeth 9. The pressing block 21 is oscillated and displaced. And with this rocking displacement, the tip end portion of the outer peripheral surface of the pressing block 21 and the inner peripheral surface of the cylinder portion 20 collide with vigor, and unpleasant vibration and noise are generated. Wear on both peripheral surfaces may be significant. The reason why such a problem occurs will be described with reference to FIGS.

  The central axis of the pressing block 21 and the central axis of the cylinder portion 20 do not transmit force between the pinion teeth 7 and the rack teeth 9 and no external force is applied to the pressing block 21. Then, as shown in FIG. 9A, they tend to almost coincide with each other. If the central axis of the pressing block 21 and the central axis of the cylinder part 20 are completely aligned, the outer peripheral surface of the pressing block 21 and the inner peripheral surface of the cylinder part 20 are all around. It will be in the state which opposes through a clearance gap. In an actual case, both the central axes are slightly inclined and the both peripheral surfaces often abut each other. However, the swing displacement of the pressing block 21 is shown in FIG. It is performed on the basis of the state shown in A). Further, in this reference state, the inner peripheral surface of the cylinder portion 20 and the outer peripheral edge of the elastic ring 26 are in light contact with each other over the entire periphery.

  On the other hand, as the pinion teeth 7 and the rack teeth 9 are provided with a torsion angle θ, the force between the pinion teeth 7 and the rack teeth 9 due to the rotation of the pinion shaft 6 is increased. At the time of transmission, a force in the axial direction of the pinion shaft 6 is applied to the rack shaft 8 as indicated by an arrow α in FIG. The direction of action of this force is reversed when the direction of rotation of the pinion shaft 6 is reversed. The rack shaft 8 has a long total length of about 400 to 800 mm and is supported by the rack guides 13 and 13 only in the vicinity of both end portions. 9) (flexible in the left-right direction), and in some cases it can be twisted, albeit slightly. Such elastic deformation of the rack shaft 8 is linked to the displacement of the portion of the rack teeth 9 meshing with the pinion teeth 7, and this displacement presses the rack shaft 8. This is connected to the displacement of the pressing block 21 in the arrow α direction. In accordance with this displacement, the pressing block 21 is oscillated and displaced corresponding to the displacement direction of the rack shaft 8 as shown exaggeratedly in FIG. The swing displacement is started with a contact portion between the inner peripheral surface of the cylinder portion 20 and the outer peripheral edge of the elastic ring 26 as a fulcrum.

  And with the said rocking displacement, the front-end | tip part of the outer peripheral surface of the said press block 21 and the inner peripheral surface of the said cylinder part 20 collide vigorously, causing the said unpleasant vibration, noise, and wear. In particular, the outer peripheral edge portion of the front end portion of the pressing block 21 (the edge portion opposite to the rack shaft 8) has a short distance from the elastic ring 26, and the force is amplified by the lever principle, In addition to the collision part between the two peripheral surfaces, the surface pressure of this collision part increases. In this state, if the pressing block 21 is displaced in the axial direction, the wear on both peripheral surfaces tends to proceed. On the other hand, if the elastic ring 26 is provided in a portion of the outer peripheral surface of the pressing block 21 that is very close to the outer edge, the outer peripheral surface of the pressing block 21 is not affected by the rocking displacement. It is possible to prevent the tip portion and the inner peripheral surface of the cylinder portion 20 from colliding with each other, thereby preventing the unpleasant vibration, noise, and wear.

  However, between the locking groove 25 for locking the elastic ring 26 and the outer end surface of the pressing block 21, there is a need for a fillet portion 27 for partitioning one side portion of the locking groove 25. become. And the width dimension of this fillet part 27 regarding the axial direction of the said press block 21 cannot be made too small if the intensity | strength linked to ensuring durability is considered. In addition, since the concave portion 24 exists on the outer end surface of the pressing block 21, it is necessary to consider securing the strength of the portion between the bottom surface of the locking concave groove 25 and the concave portion 24. In consideration of these things, it is necessary to secure a certain width dimension of the meat portion 27. When the width dimension of the meat portion 27 is increased to some extent, the distal end portion of the outer peripheral surface of the pressing block 21 and the inner peripheral surface of the cylinder portion 20 are likely to collide. For this reason, since the surface pressure of the contact portion increases, the unpleasant vibration, noise, and wear easily occur.

JP-A-55-68472 JP-A-10-217985 JP 2007-186185 A JP 2009-184591 A JP 2009-190426 A

  In view of the circumstances as described above, the present invention can prevent the outer peripheral portion of the outer peripheral surface of the pressing block from colliding with the inner peripheral surface of the cylinder portion with high surface pressure, and is durable. It was invented to realize a structure of a steering gear unit that can improve the performance.

Each of the rack and pinion type steering gear unit of the present invention has a casing, a rack shaft, a pinion shaft, a pressing block, an elastic member, as in the above-described conventionally known rack and pinion type steering gear unit. A member, a locking groove, and an elastic ring are provided.
Of these, the casing includes a cylindrical main storage portion that is open at both ends, a cylindrical sub storage portion that is provided in a twisted positional relationship with respect to the main storage portion, and that is open at one end, and the main storage portion. And a cylinder portion provided in a direction orthogonal to the main storage portion in a state where the inside and outside of the chamber are communicated.
Further, the rack shaft is provided with rack teeth on the front surface, and is installed in the main housing portion of the casing so as to be capable of axial displacement.
In addition, the pinion shaft is configured such that pinion teeth formed on the front half portion in the axial direction mesh with the rack teeth, and the base half portion in the axial direction protrudes outward from the opening of the auxiliary storage portion of the casing. In this sub-accommodating portion, it is rotatably arranged.
The pressing block is fitted in the cylinder portion so as to be movable relative to the rack shaft.
The elastic member is, for example, a compression coil spring, and is provided between the pressing block and a lid fixed to the outer end opening of the cylinder portion. Then, the pressing block is pressed toward the back surface of the rack shaft.
Moreover, the said locking groove is formed over the perimeter in the part near the outer end opening part of the said cylinder part among the outer peripheral surfaces of the said press block.
Furthermore, the elastic ring is locked in the locking groove with the outer peripheral edge projecting radially outward from the outer peripheral surface of the pressing block.

In particular, in the rack and pinion type steering gear unit according to claim 1 of the present invention, the tip of the pressing block that is closer to the outer end opening of the cylinder part than the locking groove is provided. Similarly, the outer diameter of the portion is smaller than the outer diameter of the portion closer to the rack shaft than the locking groove.
Further, in the rack and pinion type steering gear unit according to claim 2, the outer diameter of the tip portion of the pressing block that is closer to the outer end opening of the cylinder portion than the locking groove is set. The taper is gradually decreased as the distance from the locking groove is increased. Further, the maximum value of the outer diameter of the tip portion is set to be equal to or smaller than the outer diameter of the portion closer to the rack shaft than the locking groove in the pressing block.
Furthermore, the inventions described in claims 1 and 2 can be carried out simultaneously. That is, as in the invention described in claim 3, the outer diameter of the tip portion of the pressing block that is closer to the outer end opening of the cylinder portion than the locking groove is less than the locking groove. While gradually decreasing with increasing distance, the maximum value of the outer diameter of the tip portion is made smaller than the outer diameter of the portion closer to the rack shaft than the locking groove in the pressing block.
In the present invention, the same or corresponding special technical feature of the invention described in claim 1 and the invention described in claim 2 is that, in the pressing block, the cylinder portion is located more than the locking groove. The outer diameter of the portion excluding at least the base end edge (the end edge on the side of the locking groove) of the tip end portion near the outer end opening is set to be outside the portion closer to the rack shaft than the locking groove. The point is that it is smaller than the diameter.

According to the rack and pinion type steering gear unit of the present invention configured as described above, it is possible to prevent the outer peripheral surface of the tip portion of the pressing block and the inner peripheral surface of the cylinder portion from colliding vigorously with high surface pressure. , Durability can be improved.
That is, even if the pressing block swings and displaces around the contact portion between the outer peripheral edge of the elastic ring and the inner peripheral surface of the cylinder portion, the tip of the outer peripheral surface of the pressing block and the cylinder portion The inner surface will not collide vigorously.

  The reason for this is that in the case of the invention described in any one of claims 1 and 2, the diameter of the outer peripheral edge of the front end of the pressing block is determined by the locking recess at the locking groove that locks the elastic ring. This is because it is smaller than the outer diameter of the portion closer to the base end than the groove. That is, the diameter of the outer peripheral edge of the front end of the pressing block, which may collide with the inner peripheral surface of the cylinder portion with the highest surface pressure with the swing displacement, becomes the center of the swing displacement. The diameter of the contact portion between the outer peripheral edge portion of the elastic ring and the inner peripheral surface of the cylinder portion is sufficiently smaller. For this reason, even if the pressing block is slightly swung and displaced by the force shown by the arrow α in FIG. 7, the outer peripheral edge of the tip of the pressing block collides with the inner peripheral surface of the cylinder. There is nothing.

  Depending on the degree to which the outer diameters of both sides of the pressing block sandwiching the locking groove are different or the outer diameter of the tip part is gradually reduced, if the swing angle increases, There is a possibility of collision with the peripheral surface. However, even in that case, since the elastic ring is crushed elastically to some extent before the collision, the momentum of the collision is considerably attenuated, and the surface pressure is also the repulsive force of the elastic ring, Lower. Therefore, even in the above-described case and even when the swing angle is increased, the outer peripheral edge and the inner peripheral surface of the tip portion collide vigorously or the surface pressure of the collision portion becomes particularly high. Absent. As a result, in addition to suppressing the unpleasant vibration and noise as described above, the wear of the outer peripheral surface of the pressing block and the inner peripheral surface of the cylinder portion can be suppressed, and the durability of the rack and pinion type steering gear unit can be suppressed. Can be improved.

The fragmentary sectional view equivalent to the left part of FIG. 7 which shows the 1st example of embodiment of this invention. The X section enlarged view of FIG. FIG. 10 is a view similar to FIG. 9B, showing a state where the pressing block is oscillating and displaced. The figure similar to FIG. 2 which shows the 2nd example of embodiment of this invention. The partial cutting side view which shows an example of the steering device for motor vehicles incorporating the rack and pinion type steering gear unit. YY sectional drawing of FIG. The expanded ZZ sectional view of FIG. 7 is a schematic diagram showing the rack shaft taken out and viewed from above in FIG. The schematic diagram which shows the state to which a press block rock | fluctuates and displaces with the motive power transmission between a rack tooth and a pinion tooth in a neutral state (A) and an inclination state (B).

[First example of embodiment]
1 to 3 show a first example of an embodiment of the present invention corresponding to claim 1 only. The feature of the present invention including this example is that the pressing block 21a (centered on the contact portion between the outer peripheral edge of the elastic ring 26 locked in the locking groove 25 and the inner peripheral surface of the cylinder portion 20 is used. Regardless of the rocking displacement of 21b), the outer peripheral edge of the front end of the pressing block 21a (21b) and the inner peripheral surface of the cylinder 20 collide vigorously, and the surface pressure of the collision part becomes particularly high. It is in a structure to prevent. Since the structure and operation of the other parts are the same as those of the conventional structure shown in FIG. 7, the illustration and description of the equivalent parts are omitted or simplified, and the following description will focus on the characteristic parts of the present invention.

In the rack-and-pinion type steering gear unit of this example, in the pressing block 21a, a surplus portion that is a tip portion that is located closer to the outer end opening of the cylinder portion 20 than the locking groove 25 is provided. The outer diameter d of 27a is smaller than the outer diameter D of the intermediate part or the base end part (d <D), which is also closer to the rack shaft 8 than the locking groove 25. The degree of reduction is regulated by the relationship with the angle at which the pressing block 21a can swing and be displaced. The maximum value of the swingable displacement angle is the difference (RD) between the inner diameter R of the cylinder part 20 and the outer diameter D of the intermediate part or the base end part of the pressing block 21a, and the cylinder part 20 It is determined by the length L _L of the portion where the inner peripheral surface and the outer peripheral surface of the pressing block 21a are close to each other. Further, the axial distance L _S from the contact portion between the outer peripheral edge of the elastic ring 26 and the inner peripheral surface of the cylinder portion 20, which is the center of the oscillation, to the outer peripheral edge of the tip end portion of the pressing block 21 a is larger. The length L _L of the portion where the two peripheral surfaces are close to each other is much larger (L _S << _{L L} ).

  Therefore, the difference (D−d) between the outer diameter D of the intermediate portion or the base end portion and the outer diameter d of the distal end portion is the difference between the inner diameter R of the cylinder portion 20 and the outer diameter D of the pressing block 21a. (RD) is sufficient. The difference (D−d) between the outer diameters D and d may be slightly smaller than the difference (R−D) between the inner diameter R and the outer diameter D. If the difference (D-d) is equal to or greater than the difference (RD) between the inner diameter R and the outer diameter D (RD) ≧ (RD)}, the pressing force is applied regardless of the swing displacement. It is possible to reliably prevent the outer peripheral edge of the tip of the block 21a and the inner peripheral surface of the cylinder part 20 from colliding with each other. Since the difference (RD) between the inner diameter R and the outer diameter D is slight, the difference between the outer diameters D and d (D-d) is the difference between the inner diameter R and the outer diameter D (RD). Even if it is as described above, there is no particular problem with respect to the locking groove 25 locking the elastic ring 26.

  The pressing block 21a is made of a metal such as an iron alloy or an aluminum alloy, or a synthetic resin such as a polyamide resin or a polytetrafluoroethylene resin. In the case of metal, a low friction material such as synthetic resin or oil-impregnated metal is attached to the surface that is in sliding contact with the back surface of the rack shaft 8. In any case, the outer peripheral surface of the pressing block 21a is chamfered at the outer peripheral edge portion of the inner end portion which is the end portion on the rack shaft 8 side, and the pressing block 21a is placed in the cylinder portion 20, It can be easily inserted.

  As described above, in the case of the rack and pinion type steering gear unit of the present example, the outer diameter d of the fillet portion 27a that is the distal end portion of the pressing block 21a is set to be larger than the outer diameter D of the intermediate portion or the proximal end portion. It is small (d <D). For this reason, with the power transmission between the pinion shaft 6 and the rack shaft 8, even if the pressing block 21a swings and displaces around the portion held down by the inner peripheral edge of the elastic ring 26a, The outer peripheral edge of the tip of the pressing block 21a and the inner peripheral surface of the cylinder 20a do not collide. As a result, it is possible to prevent unpleasant vibration, noise, or significant wear as described above, regardless of the rocking displacement of the pressing block 21a accompanying the power transmission.

[Second Example of Embodiment]
FIG. 4 shows a second example of an embodiment of the present invention corresponding to claims 1 to 3. In the case of this example, the outer diameter of the fillet portion 27b, which is the tip portion of the pressing block 21b closer to the outer end opening of the cylinder portion 20 than the locking groove 25, is set to the locking groove. It is gradually decreased as it gets away from 25. In other words, the outer peripheral surface of the thin portion 27b is a tapered tapered partial conical convex surface. In addition, the maximum value of the outer diameter of the thick portion 27b, that is, the outer diameter d of the portion of the thick portion 27b adjacent to the locking groove 25 is set to the locking portion of the pressing block 21b. It is smaller than the outer diameter D of the intermediate part or the base end part, which is closer to the rack shaft than the concave groove 25 (d <D).

  Regarding the inclination angle β of the outer peripheral surface of the meat portion 27b, in the case of the first example of the embodiment described above, the pressure is reduced as in the case where the degree of reducing the outer diameter d of the meat portion 27a is restricted. The block 21a is regulated in relation to the angle at which the block 21a can be displaced. Since the maximum value of the swingable displacement angle is very small, the inclination angle β of the outer peripheral surface of the fillet portion 27b may be small, but even if it is large, it is completely from the surface of preventing collision caused by the swing displacement. no problem. However, if the inclination angle β is too small, the processing of the fillet portion 27b becomes troublesome (accurately ensuring accuracy for restricting the angle to prevent collision). On the other hand, if it is too large, the strength of the edge portion on the side of the locking groove 25 in the thin portion 27a is lowered. Considering these matters, it is appropriate to regulate the inclination angle β to about 5 to 10 degrees.

As described above, in the case of the structure of this example in which the outer peripheral surface of the surplus portion 27b is a partially conical convex surface, the pinion shaft 6 and the rack shaft 8 are the same as in the case of the first example of the embodiment described above. Even if the pressing block 21b swings and displaces around the portion restrained by the inner peripheral edge of the elastic ring 26 along with the power transmission to (see FIG. 1), the tip of the pressing block 21b The outer peripheral edge does not collide with the inner peripheral surface of the cylinder part 20. As a result, it is possible to prevent the occurrence of unpleasant vibration, noise, or significant wear as described above, regardless of the swing displacement of the pressing block 21b accompanying the power transmission.
Since the configuration and operation of the other parts are the same as in the first example of the above-described embodiment, illustration and description regarding the equivalent parts are omitted.

DESCRIPTION OF SYMBOLS 1 Steering wheel 2 Steering shaft 3 Universal joint 4 Intermediate shaft 5 Steering gear unit 6 Pinion shaft 7 Pinion tooth 8 Rack shaft 9 Rack tooth 10 Casing 11 Main storage part 12 Sub-storage part 13 Rack guide 14 Spherical joint 15 Tie rod 16 Radial needle bearing 17 Ball bearing 18 Retaining screw cylinder 19 Seal ring 20 Cylinder part 21, 21a, 21b Press block 22 Lid 23 Spring 24 Recess 25 Locking groove 26 Elastic ring 27, 27a, 27b Ductile part

Claims (3)

  A cylindrical main storage portion with both ends open, a cylindrical sub storage portion provided in a twisted positional relationship with respect to the main storage portion, and one end open, and a state in which the inside and outside of the main storage portion are communicated And a casing having a cylinder portion provided in a direction orthogonal to the main storage portion, a rack shaft provided with rack teeth on the front surface and installed in the main storage portion of the casing so as to be axially displaceable, and a shaft The pinion teeth formed in the front half of the direction are meshed with the rack teeth and the base half in the axial direction protrudes outward from the opening of the secondary storage part of the casing and can be rotated in the secondary storage part. A pinion shaft disposed in the cylinder portion, a pressure block that is fitted in the cylinder portion so as to be movable relative to the rack shaft, and a lid body fixed to the pressure block and an outer end opening of the cylinder portion. Between An elastic member that presses the pressing block toward the back surface of the rack shaft, and a locking groove formed on the outer peripheral surface of the pressing block near the outer end opening of the cylinder portion over the entire circumference. And a rack-and-pinion type steering gear unit having an outer peripheral edge projecting radially outward from the outer peripheral surface of the pressing block and being locked in the locking groove. In the pressing block, the outer diameter of the front end portion that is closer to the outer end opening of the cylinder portion than the locking groove is larger than the outer diameter of the portion closer to the rack shaft than the locking groove. The rack and pinion type steering gear unit is characterized by a smaller size.   A cylindrical main storage portion with both ends open, a cylindrical sub storage portion provided in a twisted positional relationship with respect to the main storage portion, and one end open, and a state in which the inside and outside of the main storage portion are communicated And a casing having a cylinder portion provided in a direction orthogonal to the main storage portion, a rack shaft provided with rack teeth on the front surface and installed in the main storage portion of the casing so as to be axially displaceable, and a shaft The pinion teeth formed in the front half of the direction are meshed with the rack teeth and the base half in the axial direction protrudes outward from the opening of the secondary storage part of the casing and can be rotated in the secondary storage part. A pinion shaft disposed in the cylinder portion, a pressure block that is fitted in the cylinder portion so as to be movable relative to the rack shaft, and a lid body fixed to the pressure block and an outer end opening of the cylinder portion. Between An elastic member that presses the pressing block toward the back surface of the rack shaft, and a locking groove formed on the outer peripheral surface of the pressing block near the outer end opening of the cylinder portion over the entire circumference. And a rack-and-pinion type steering gear unit having an outer peripheral edge projecting radially outward from the outer peripheral surface of the pressing block and being locked in the locking groove. In the pressing block, the outer diameter of the tip portion that is closer to the outer end opening of the cylinder part than the locking groove is gradually reduced as the distance from the locking groove is increased. A rack and pinion type steering gear unit, wherein a maximum value of an outer diameter is equal to or smaller than an outer diameter of a portion closer to the rack shaft than the locking groove in the pressing block.   The rack and pinion type steering gear unit according to claim 2, wherein a maximum value of an outer diameter of the tip portion is smaller than an outer diameter of a portion closer to the rack shaft than the locking groove in the pressing block.

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