JP5601415B2 - Rack and pinion type steering gear unit - Google Patents

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.

  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. 7 to 9 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. 8-9 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, rack teeth 9 having a twist angle θ as schematically shown in FIG. 10 are used, and helical gears having a similar twist angle are used for the pinion teeth 7 in accordance therewith. 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 own 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.
In order to smoothly displace the pressing block 21 in the axial direction, grease is filled between the outer peripheral surface of the pressing block 21 and the inner peripheral surface of the cylinder portion 20. For this reason, a sliding resistance based on the viscosity of the grease (shearing due to the presence of a grease film between the two peripheral surfaces) is formed between the outer peripheral surface of the pressing block 21 and the inner peripheral surface of the cylinder portion 20. Resistance) occurs. The pressing block 21 is fitted to the cylinder portion 20 over the entire axial length, and has a relatively large outer diameter. For this reason, the area where the grease film can exist is large, and when the grease film exists over the entire surface, the sliding between the outer peripheral surface of the pressing block 21 and the inner peripheral surface of the cylinder portion 20 is performed. Dynamic resistance increases. In order to suppress the influence of such sliding resistance, a certain amount of gap is provided between the outer peripheral surface of the pressing block 21 and the inner peripheral surface of the cylinder portion 20.

  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 (the end portion opposite to the engaging portion with the rack shaft 8) of the outer peripheral surface of the pressing block 21 and the inner peripheral surface of the cylinder portion 20 May collide vigorously, generating unpleasant vibrations and noises, or causing significant wear on both peripheral surfaces. 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. 11A, 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 shown 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. 11 in the left-right direction) and may be twisted in some cases, 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.

  As the rocking displacement occurs, the outer peripheral edge of the tip of the pressing block 21 and the inner peripheral surface of the cylinder 20 collide with each other, causing 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.

  Patent Document 2 discloses a structure that prevents vibration, noise, and wear caused by collision of both surfaces by interposing a buffer member made of synthetic resin between the outer peripheral surface of the pressing block and the inner peripheral surface of the cylinder portion. Is described. In the case of such a structure, the cost for the material and manufacture of the buffer member increases.

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 surface of the pressing block from colliding with the outer peripheral surface of the tip and the inner peripheral surface of the cylinder portion with high surface pressure. The present invention has been invented to realize a favorable structure of the steering gear unit at a low cost.

The rack and pinion type steering gear unit of the present invention, like the conventionally known rack and pinion type steering gear unit, has a casing, a rack shaft, a pinion shaft, a pressing block, a lid, And an elastic member.
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 lid is fixed to the outer end opening of the cylinder portion.
The elastic member is, for example, a compression coil spring, and is provided between the pressing block and the lid. Then, the rear surface of the rack shaft is pressed by the inner end surface in the axial direction of the pressing block .

In particular, in the rack and pinion type steering gear unit of the present invention, a fitting portion is provided between the pressing block and the lid. The fitting portion is a recess formed on the outer end surface in the axial direction of the pressing block and a small diameter portion formed on the inner end portion in the axial direction of the lid body and having a smaller outer diameter than the portion near the outer end in the axial direction. It consists of a certain convex part, and this convex part and the said recessed part are fitted so that the displacement of an axial direction is possible. Further, the difference between the outer diameter of the convex portion and the inner diameter of the concave portion in which the convex portion is fitted is the difference between the outer diameter of the pressing block and the inner diameter of the cylinder portion in which the pressing block is fitted. Smaller than that.
At the same time, the outer peripheral edge of the elastic ring locked in the locking groove formed on the outer peripheral surface of the pressing block over the entire periphery, and the outer end surface of the convex portion of the lid and the axially outer side of the pressing block. The outer peripheral edge of the damper provided between the end surfaces is brought into contact with the inner peripheral surface of the cylinder part.
Further, the cross-sectional area of the damper is made larger than the cross-sectional area of the elastic ring.

According to the rack and pinion type steering gear unit of the present invention configured as described above, the outer peripheral edge of the front end of the pressing block and the inner peripheral surface of the cylinder can be prevented from colliding with force, and the durability is excellent. Can be.
That is, when the pressing block tends to swing, the pressing block is greatly swung in the radial direction by the fitting portion provided between the pressing block and the lid. Thus, the outer peripheral edge of the tip of the pressing block and the inner peripheral surface of the cylinder portion can be prevented from colliding with a high surface pressure. 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.

In the case of the structure of the present invention, when the pressing block swings and displaces, the outer peripheral edge of the tip of the convex part and the inner peripheral surface of the concave part come into contact with each other. Unpleasant vibration and noise, and wear on both sides can be suppressed. That is, since the axial dimension of the fitting part composed of the convex part and the concave part is smaller than the axial dimension of the pressing block and the diameter is small, the sliding resistance generated in the fitting part is the same as the conventional structure. In this case, the sliding resistance generated between the outer peripheral surface of the pressing block and the inner peripheral surface of the cylinder portion is much smaller. Therefore, the gap between the convex portion and the concave portion can be made smaller than the gap between the outer peripheral surface of these pressing blocks and the inner peripheral surface of the cylinder portion. As a result, the momentum of the collision prior to the outer peripheral edge of the tip of the convex part coming into contact with the inner peripheral surface of the concave is that the outer peripheral edge of the tip of the pressing block is It can be much smaller than the momentum which collides with the inner peripheral surface, and unpleasant vibration and noise can be generated, and wear between the outer peripheral surface of the convex portion and the inner peripheral surface of the concave portion can be suppressed.
Further, according to the structure of the present invention, when the pressing block is displaced in the axial direction, it is possible to prevent the outer end surface in the axial direction of the pressing block from colliding with the back end surface of the convex portion of the lid vigorously. .

The fragmentary sectional view equivalent to the left part of FIG. 9 which shows the 1st example of the reference example regarding this invention. The figure similar to FIG. 1 which shows an example of embodiment of this invention . The figure similar to FIG. 1 which shows the 2nd example of the reference example regarding this invention . The figure similar to FIG. 1 which shows the 3rd example . The figure similar to FIG. 1 which shows the 4th example. The figure similar to FIG. 1 which shows the same 5th example. 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. XX sectional drawing of FIG. The expanded YY sectional view of FIG. FIG. 9 is a schematic diagram showing the rack shaft taken out and viewed from above in FIG. 8. 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 reference example of the present invention]
FIG. 1 shows a first example of a reference example related to the present invention. The features of each example of the reference example including the present reference example and one example of the embodiment to be described later are that the outer peripheral edge of the tip end of the pressing block 21a is independent of the rocking displacement of the pressing block 21a. The structure for preventing the inner peripheral surface of the cylinder portion 20 of the casing 10 from colliding with vigor. Since the structure and operation of the other parts are the same as those of the conventional structure shown in FIG. 9, the illustration and description of the equivalent parts are omitted or simplified, and the following description will focus on the characteristic parts of this reference example. To do.

In the rack and pinion type steering gear unit of this reference example, the inner end portion of the lid body 22a has a cylindrical outer peripheral surface concentric with the lid body 22a, and has an outer diameter that is closer to the outer end portion. A small-diameter portion 27 is formed. The small diameter portion 27 is formed on the outer end surface of the pressing block 21a, and the pressing block 21a has a cylindrical inner peripheral surface concentric with the pressing block 21a. It is fitted in a state in which the displacement (the pressing block 21a moves in the cylinder portion 20 with respect to the rack shaft 8) in the direction is possible. In the case of this reference example, the difference (R _24a -r ₂₇ ) between the outer diameter r ₂₇ of the small-diameter portion 27 of the lid body 22a and the inner diameter R _{24a of the} concave portion 24a is defined as the outer diameter r _{21a of the} pressing block 21a. The difference (R ₂₀ −r _21a ) from the inner diameter R ₂₀ of the cylinder portion 20 is smaller than {(R _24a −r ₂₇ ) <(R ₂₀ −r _21a )}.

  Further, a metal spacer 28 such as an aluminum alloy is provided between the outer end surface of the pressing block 21a and the inner end surface of the small diameter portion 27 of the lid 22a. The spacer 28 has a circular shape and has elasticity in the direction of increasing the diameter. An elastic ring 29 made of an elastic material such as rubber is locked around the spacer 28, and the outer peripheral edge of the elastic ring 29 is elastically pressed against the inner peripheral surface of the cylinder portion 20. . The width dimension of the spacer 28 in the axial direction is made smaller than the distance between the back end face of the small diameter portion 27 and the outer end face of the pressing block 21a, thereby enabling the axial displacement of the pressing block 21a in both directions. Yes.

The rack-and-pinion type steering gear unit of this reference example configured as described above has the difference between the outer diameter r ₂₇ of the small diameter portion ₂₇ and the inner diameter R _{24a of the} concave portion 24a, and the outer diameter r of the pressing block 21a. _21a and, since is smaller than the difference between the inner diameter R ₂₀ of the cylinder portion 20, when the press block 21a has swings, a front end outer periphery of the pressing block 21a, the cylinder portion 20 Before the inner peripheral surface collides, the outer peripheral edge of the distal end portion of the small diameter portion 27 and the inner peripheral surface of the concave portion 24a come into contact with each other. As a result, it is possible to prevent the front end portion of the pressing block 21a and the inner peripheral surface of the cylinder portion 20 of the casing 10 from colliding with each other regardless of the swinging displacement of the pressing block 21a. Incidentally, at this time, the tip outer periphery of the small diameter portion 27, but the inner peripheral surface of the recess 24a abuts, the difference between the inner diameter R _24a having an outer diameter r ₂₇ and the recess 24a of the small diameter portion 27, for the less than the difference between the outer diameter r _21a to the inner diameter R ₂₀ of the cylinder portion 20 of the press block 21a, the force of collision prior to contact is smaller, unpleasant vibration and noise, the outer peripheral surface of the small-diameter portion 27 And wear with the inner peripheral surface of the recess 24a can be prevented.
In the case of this reference example, the small diameter portion 27 is formed directly on the lid 22a and the concave portion 24a is formed directly on the pressing block 21a by lathe processing. Will not increase.

  Further, in the case of this reference example, a spacer 28 is provided between the outer end surface of the pressing block 21a and the inner end surface of the lid 22a, and an elastic ring 29 is locked around the spacer 28. Therefore, foreign matter such as muddy water can be prevented from entering the casing 10 through the gap between the inner peripheral surface of the cylinder portion 20 and the outer peripheral surface of the lid 22a. In the case of this reference example, in order to lock the elastic ring 29, it is not necessary to form an independent locking groove on the outer peripheral surface of the lid 22a, and the cost can be reduced.

[Example of Embodiment]
FIG. 2 shows an example of an embodiment of the present invention. In the case of this example, a damper 30 made of an elastic material such as an elastomer such as rubber is provided between the outer end surface of the pressing block 21a and the inner end surface of the small diameter portion 27 of the lid 22a. The damper 30 prevents foreign matter such as muddy water from entering the casing 10 through the gap between the inner peripheral surface of the cylinder portion 20 and the outer peripheral surface of the lid body 22a, and the pressing block 21a has a shaft. When displaced in the direction, the outer end surface of the pressing block 21a is prevented from colliding with the back end surface of the small-diameter portion 27 of the lid body 22a vigorously. Further, with respect to a virtual plane passing through the central axis of the cylinder portion 20, the cross-sectional area of the damper 30 is made larger than the cross-sectional area of the elastic ring 26 locked to the outer peripheral surface of the pressing block 21a.
Since the configuration and operation of the other parts are the same as those of the first example of the reference example related to the present invention described above, illustration and description regarding the equivalent parts are omitted.

[ Second Example of Reference Example of the Present Invention ]
FIG. 3 shows a second example of a reference example relating to the present invention . In the case of the structure of this reference example , a locking groove 31 is formed on a part of the outer peripheral surface near the outer end of the lid 22b over the entire circumference, and an elastomer such as rubber is formed in the locking groove 31. An elastic ring 29a made of an elastic material such as is locked. With this configuration, foreign matter such as muddy water is prevented from entering the casing 10 through the gap between the inner peripheral surface of the cylinder portion 20 and the outer peripheral surface of the lid body 22b.
Since the configuration and operation of the other parts are the same as those of the first example of the reference example related to the present invention described above, illustration and description regarding the equivalent parts are omitted.

[Third example of reference example of the present invention]
FIG. 4 shows a third example of the reference example related to the present invention. In the case of this reference example, a small-diameter portion 27a having a cylindrical outer peripheral surface concentric with the pressing block 21b and having a smaller outer diameter than the inner end portion is formed at the outer end portion of the pressing block 21b. ing. The small-diameter portion 27a is formed on the inner end surface of the lid body 22c, and the pressing block 21b is axially formed with respect to the lid body 22c. (The pressing block 21b is fitted in a state where it can move in and out of the cylinder portion 20 with respect to the rack shaft 8).
Further, between the rear end surface of the small-diameter portion 27a of the pressing block 21b and the inner end surface of the lid body 22c, a metal-made non-circular spacer 28a such as an aluminum alloy is provided. Then, an elastic ring 29b made of an elastic material such as an elastomer such as rubber is locked around the spacer 28a, and the outer peripheral edge of the elastic ring 29b is brought to the inner peripheral surface of the cylinder portion 20 by the spacer 28a. Pressing.
Since the configuration and operation of the other parts are the same as those of the first example of the reference example related to the present invention described above, illustration and description regarding the equivalent parts are omitted.

[Fourth example of a reference example related to the present invention]
FIG. 5 shows a fourth example of the reference example relating to the present invention. In the case of this reference example, a damper 30a made of an elastic material such as an elastomer such as rubber is provided between the back end surface of the small diameter portion 27a of the pressing block 21b and the inner end surface of the lid 22c.
Since the configuration and operation of the other parts are the same as those of the above-described example of the embodiment and the above-described third example of the reference example related to the present invention, the illustration and description of the equivalent parts are omitted.

[Fifth Example of Reference Example Related to the Present Invention]
FIG. 6 shows a fifth example of the reference example relating to the present invention. In the case of the structure of this reference example, a locking groove 31a is formed on a part of the outer peripheral surface near the outer end of the lid 22d over the entire circumference, and an elastomer such as rubber is formed in the locking groove 31a. The elastic ring 29c made of an elastic material such as is locked.
Since the configuration and operation of the other parts are the same as those of the above-described example of the embodiment and the second to third examples of the reference example related to the present invention, the illustration and description of the equivalent part are omitted.

  When implementing the present invention, for the structure of the fitting portion provided between the pressing block and the lid, if the collision between the outer peripheral edge of the tip of the pressing block and the inner peripheral surface of the cylinder portion can be prevented, It doesn't matter. For example, it is also possible to form a convex portion by fixing a cylindrical member to the lid body by interference fitting or the like, and this convex portion can be fitted to the concave portion provided in the pressing block so as to be capable of axial displacement. good.

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 Press block 22 Lid body 23 Spring 24, 24a Recess 25 Locking groove 26 Elastic ring 27, 27a Small diameter part 28, 28a Spacer 29, 29a-29c Elastic ring 30 30a Damper 31 Locking groove 32 Recess

Claims (1)

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,
Rack teeth provided on the front surface, and a rack shaft installed in the main housing part of the casing so as to be capable of axial displacement;
The pinion teeth formed in the first half of the axial direction are meshed with the rack teeth, and the base half of the axial direction protrudes outward from the opening of the secondary storage portion of the casing, and rotates in the secondary storage portion. A pinion shaft arranged as possible,
In the cylinder portion, a pressing block that is fitted so as to be capable of moving in a perspective direction with respect to the rack shaft;
A lid fixed to the outer end opening of the cylinder portion;
An elastic member provided between the pressing block and the lid ,
In a rack and pinion type steering gear unit that presses the back surface of the rack shaft with the axially inner end surface of the pressing block ,
Between the pressing block and the lid, a recess formed on the outer end surface in the axial direction of the pressing block, and an outer portion closer to the outer end in the axial direction formed at the inner end in the axial direction of the lid. A convex portion that is a small-diameter portion having a small diameter, and a fitting portion is provided in which the convex portion and the concave portion are fitted so as to be capable of axial displacement, and the outer diameter of the convex portion and the convex portion are The difference between the inner diameter of the recessed portion fitted inside is made smaller than the difference between the outer diameter of the pressing block and the inner diameter of the cylinder portion on which the pressing block is fitted, and the entire outer peripheral surface of the pressing block is The outer peripheral edge of the elastic ring locked in the locking groove formed over the circumference, and the outer peripheral edge of the damper provided between the back end face of the convex portion of the lid and the axial outer end face of the pressing block the has abutted on the inner peripheral surface of each of the cylinder portion, the bullet the cross-sectional area of the damper Rack and pinion steering gear unit, characterized in that is made larger than the cross-sectional area of the ring.

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