JP2012051406A - Rack-and-pinion type steering gear unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a structure which can simplify the manufacturing work, the parts management work and the assembly of a seal ring 29a and a cover 30a for preventing ingress of foreign matters in a casing 10 through a space between a pinion shaft 6a and an opening part of a sub-accommodating part 12, and can reduce the manufacturing cost.SOLUTION: The seal ring 29a and the cover 30a are integrally formed of an elastic material. The cover 30a is provided on an upper end of the seal ring 29a in an radially outwardly extending manner from a part projecting outwardly from the sub-accommodating part 12. Further, the seal ring 29a is brought into slidable contact with the entire circumference of an inner circumferential surface of a screw cylinder 22a while suppressing an outer circumferential edge in a housed and fixed manner to an intermediate part of the pinion shaft 6a.

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. 3 has been widely known. 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. FIGS. 11 to 13 show structures described in Patent Documents 1 and 2 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.

  The steering gear unit 5 is formed by meshing pinion teeth 7 provided on a part of the pinion shaft 6 in the axial direction with rack teeth 9 provided on the front surface of the rack shaft 8. 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. And the base end part of the tie rods 14 and 14 is couple | bonded with the both ends via the spherical couplings 13 and 13, respectively. The tip portions of the tie rods 14 and 14 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 a radial bearing 15 at the back end portion of the auxiliary storage portion 12. Further, the intermediate portion of the pinion shaft 6 is supported by a single row ball bearing 16 such as a deep groove type, a three-point contact type, or a four-point contact type at a portion near the opening of the sub storage portion 12. Of the inner ring 17 and the outer ring 18 constituting the ball bearing 16, the inner ring 17 includes an inner diameter side step surface 19 formed at an intermediate portion of the pinion shaft 6 and a conical stopper locked to the intermediate portion of the pinion shaft 6. It is sandwiched between the wheel 20. In addition, the outer ring 18 is formed on the outer diameter side step surface 21 which is the step portion described in the claims and formed in the middle portion of the inner peripheral surface of the sub storage portion 12, and the opening portion of the sub storage portion 12. It is clamped between the screwed holding screw cylinder 22. With this configuration, the front half of the pinion shaft 6 is supported in the sub-accommodating portion 12 so as to be able to support a radial load and a thrust load (to prevent rotation in the axial direction).

  In addition, a cylinder tube portion 23 is provided on the opposite side of the sub storage portion 12 with respect to the diameter direction of the main storage portion 11, and a sliding block 25 in which a pressing roller 24 is rotatably supported in the cylinder tube portion 23. Is fitted. A spring 27 is provided between the cover body 26 screwed into the opening of the cylinder cylinder portion 23 and the pressing block 25 to press the pressing roller 24 toward the rack shaft 8. The rack shaft 8 is elastically pressed toward the pinion shaft 6 to eliminate backlash at the meshing portion between the pinion teeth 7 and the rack teeth 9. Further, the meshing state of the meshing part is properly maintained regardless of the force in the direction away from the pinion shaft 6 applied to the rack shaft 8 with the power transmission at the meshing part of the teeth 7 and 9. .

  When the steering angle is applied to the left and right front wheels, when the pinion shaft 6 is rotated by the operation of the steering wheel 1, the rack shaft 8 is moved based on the engagement of the pinion teeth 7 and the rack teeth 9. Displace in the axial direction. 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.

  The steering gear unit 5 as described above is generally in a state in which the pinion shaft 6 is positioned upward in the engine room of the automobile (the state shown in FIG. 13 or a state inclined slightly from this state). ). Therefore, a structure for preventing foreign matter such as muddy water that gets down with traveling from entering the casing 10 is required. Among them, the opening portions at both ends of the main storage portion 11 are sealed by spanning bellows 28 and 28 (see FIG. 11) between both end portions of the main storage portion 11 and both end portions of the rack shafts 8. To do.

  On the other hand, the opening of the sub-accommodating portion 12 is sealed by a seal ring 29 fitted in the holding screw cylinder 22 and the sub-accommodating portion is covered by a cover 30 externally fitted to the intermediate portion of the pinion shaft 6. The opening of the portion 12 is covered. The holding screw cylinder 22 is made by machining a material such as a steel material, and has an inward flange 31 at an intermediate portion of the inner peripheral surface. The seal ring 29 is fitted in an inner diameter portion of the set screw cylinder 22 on the outer space side of the inward flange portion 31, and an inner peripheral edge thereof is an outer periphery of an intermediate portion of the pinion shaft 6. The surface is in sliding contact with the entire circumference.

  The cover 30 is integrally formed of an elastic material such as rubber, and includes a fitting portion 32, a cover plate portion 33, and a peripheral wall portion 34. Among these, the fitting part 32 is provided in the inner peripheral edge part of the cover 30, and in order to ensure the required fitting strength, a short cylinder having a certain thickness dimension in the radial direction. It is in the shape. An inner diameter of the fitting portion 32 in a free state is slightly smaller than an outer diameter of a portion of the pinion shaft 6 where the cover 30 is to be mounted. Further, the cover plate portion 33 is provided in a state extending radially outward from the outer peripheral surface of the lower end portion of the fitting portion 32, and has an outer diameter slightly larger than the outer diameter of the sub storage portion 12. It is an annular plate shape having Further, the peripheral wall portion 34 has a short cylindrical shape having an inner diameter slightly larger than the outer diameter of the sub-accommodating portion 12, and is provided over the entire circumference in a state of hanging downward from the outer peripheral edge of the cover plate portion 33. It has been. Such a cover 30 is assembled by fitting the fitting portion 32 to an appropriate position of the intermediate portion of the pinion shaft 6 by an interference fit while elastically expanding the inner diameter of the fitting portion 32. In this assembled state, the cover plate portion 33 is positioned slightly above the upper end opening edge of the sub storage portion 12, and the lower half portion of the peripheral wall portion 34 is positioned around the upper end portion of the sub storage portion 12. To do.

In the case of the conventional structure as described above, the seal ring 29 and the cover 30 are separate, and the seal ring 29 is fitted into the holding screw cylinder 22 and the cover 30 is similarly attached to the pinion shaft. 6 is disadvantageous in terms of suppressing the manufacturing cost of the rack and pinion type steering gear unit in the following points.
First, since the seal ring 29 and the cover 30 are individually manufactured, the manufacturing work and the parts management work are troublesome.
Secondly, in the process of assembling the steering gear unit 5, the seal ring 29 is fitted into the holding screw cylinder 22, and the cover 30 is fitted to the pinion shaft 6. In this way, since the members 29 and 30 arranged adjacent to each other in the axial direction are assembled to separate members, the assembly work cannot be consolidated, and the assembly work of the steering gear unit 5 can be made more efficient. Is disadvantageous.

JP 2007-186185 A JP 2009-184591 A JP 2009-190426 A

  In view of the circumstances as described above, the present invention provides a seal ring and cover manufacturing operation, parts management operation, and assembly that prevent foreign matter from entering the casing through the gap between the pinion shaft and the opening of the sub-accommodating portion. It was invented to realize a structure that can simplify the work and reduce the manufacturing cost.

The rack and pinion type steering gear unit of the present invention is similar to the conventionally known rack and pinion type steering gear unit, and includes a casing, a rack shaft, a pinion shaft, a bearing, a holding screw cylinder, A seal ring and a cover are provided.
Of these, the casing has a cylindrical main storage portion that is open at both ends, and a cylindrical sub storage portion that is provided at a twisted position with respect to the main storage portion and is open at one end.
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. Therefore, it is arranged in the sub-accommodating portion.
The bearing is provided between the outer peripheral surface of the intermediate portion of the pinion shaft and a portion near the opening of the inner peripheral surface of the sub storage portion, and rotatably supports the pinion shaft in the sub storage portion.
Further, the set screw cylinder is screwed to the opening side end portion of the inner peripheral surface of the sub-accommodating portion, and the bearing is pressed against the step portion provided in the intermediate portion of the inner peripheral surface of the sub-accommodating portion. .
The seal ring is provided between the inner peripheral surface of the set screw cylinder and the outer peripheral surface of the intermediate portion of the pinion shaft.
Further, the cover is externally fitted to a portion protruding from the sub storage portion at an intermediate portion of the pinion shaft. And the opening part of this sub accommodating part is covered with the said holding screw cylinder.

In particular, in the rack and pinion type steering gear unit of the present invention, the seal ring and the cover are integrally formed of an elastic material such as an elastomer such as rubber.
And the said cover is provided in the state extended from the part which protruded out of the said auxiliary | assistant storage part in the axial direction edge part of the said seal ring to radial direction outward.
Further, the outer periphery of the seal ring is in sliding contact with the inner peripheral surface of the holding screw cylinder over the entire circumference in a state where the seal ring is fitted and fixed to the intermediate portion of the pinion shaft.

  When implementing the rack and pinion type steering gear unit of the present invention as described above, the inner peripheral surface of the set screw cylinder protrudes radially inward as in the invention described in claim 2. A cylindrical surface with no buttocks. Further, the seal ring is formed by reinforcing a portion closer to the inner diameter of the annular elastic material with an annular cored bar.

As described above, in the case of the rack and pinion type steering gear unit of the present invention, the seal ring and the cover are integrated, and the seal ring and the cover are externally fitted to the intermediate portion of the pinion shaft, and the outside of the seal ring is removed. A configuration is adopted in which the peripheral edge is held down and brought into sliding contact with the inner peripheral surface of the screw cylinder. For this reason, it is possible to simplify the manufacturing operation, the component management operation, and the assembling operation of the seal ring and the cover, and the manufacturing cost can be reduced.
Furthermore, since the preferable structure described in Claim 2 makes the internal peripheral surface of a holding screw cylinder the cylindrical surface which does not have a collar part which protrudes to a radial inside, the said holding screw cylinder is made by forging with a short processing time. This makes it possible to reduce the manufacturing cost.

The figure equivalent to the expanded AA cross section of FIG. 12 which shows the 1st example of embodiment of this invention in the state which faced the cover upwards according to a use condition. BB sectional drawing of FIG. The figure similar to FIG. 1 which shows the 2nd example of embodiment of this invention. CC sectional drawing of FIG. The figure similar to FIG. 1 which shows the 3rd example of embodiment of this invention. The figure similar to FIG. 1 which shows the 4th example. The figure similar to FIG. 1 which shows the same 5th example. The figure similar to FIG. 1 which shows the 6th example. The figure similar to FIG. 1 which shows the said 7th example. The figure similar to FIG. 1 which shows the 8th 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. DD sectional drawing of FIG. The AA sectional view of Drawing 12 shown in the state where the cover turned up according to a use state.

[First example of embodiment]
1 and 2 show a first example of an embodiment of the present invention. The feature of the present invention including this example is the structure of the sealing device provided between the opening of the sub-accommodating portion 12 in the casing 10 and the intermediate portion of the pinion shaft 6a. Since the structure and operation of other parts are the same as those of the conventional structure shown in FIG. 13 described above, the same parts are denoted by the same reference numerals, and redundant description is omitted or simplified. The explanation will be focused on.

  In the steering gear unit 5a of this example, the seal ring 29a and the cover 30a constituting a seal device provided between the opening of the sub-accommodating portion 12 and the intermediate portion of the pinion shaft 6a are made of an elastomer such as rubber. The elastic material is integrally formed by injection molding. That is, a thin, substantially cylindrical seal lip portion 35 is formed at a portion near the outer diameter of the fitting portion 32a provided at the center of the cover 30a. The cross-sectional shape of the seal lip portion 35 is a partial arc shape in which the outer peripheral surface side is a convex surface. An extension ring 36 is installed on the inner diameter side of the seal lip portion 35 to give the seal lip portion 35 elasticity in the direction of expanding the outer diameter. In the case of this example, the fitting portion 32a is provided on the upper end portion of the pinion shaft 6a protruding above the upper end opening of the sub-accommodating portion 12 in order to connect the yoke of the universal joint 3 (see FIG. 11). The male serration portion 37 is formed up to the outer fitting portion. Accordingly, the center hole 38 of the fitting portion 32a has a serration hole shape that fits with the male serration portion 37 without a gap.

  On the other hand, the cover 30a is provided with the seal lip portion 35 in the fitting portion 32a, and the cover plate portion 33a is replaced with the cover plate portion 33a as the fitting portion 32a has a function as the seal ring 29a. It is provided in a state of being biased toward the upper end of the fitting portion 32a. That is, the inner peripheral edge portion of the cover plate portion 33a is continued to a portion protruding outside the auxiliary storage portion 12 at the upper end portion in the axial direction of the fitting portion 32a that also functions as the seal ring 29a. . In other words, by providing the fitting portion 32a in a state of projecting downward from the inner peripheral edge portion of the cover plate portion 33a, the fitting portion 32a is provided on the inner peripheral surface of the upper end portion of the auxiliary storage portion 12 and the pinion shaft. The fitting portion 32a can be made to function as the seal ring 29a so that it can be pushed into an annular space between the outer peripheral surface of the intermediate portion 6a. A peripheral wall portion 34a is formed on the outer peripheral edge portion of the cover plate portion 33a so as to hang downward. The configuration of the peripheral wall portion 4a is the same as that of the conventional structure shown in FIG.

  Further, in the case of this example, the holding screw cylinder 22a to be screwed into the opening of the sub-accommodating portion 12 is subjected to a forging process on a material such as carbon steel to form a cylindrical intermediate material, and then to a necessary portion. By forming the male screw 39 by die processing, it has a substantially cylindrical shape. That is, the inner peripheral surface of the set screw cylinder 22a is a cylindrical surface that does not have a flange portion protruding radially inward. In the case of this example, a tapered surface inclined in a direction in which the inner diameter increases toward the opening edge at the lower end portion located on the inner space side of the sub storage portion 12 in the assembled state to the sub storage portion 12. 40 is formed. The tapered surface 40 functions as a draft for extracting the die from the inner diameter side when the holding screw cylinder 22a is processed by forging. Of the inner peripheral surface of the set screw cylinder 22a, the axial intermediate portion or the upper end portion, which is out of the tapered surface 40, is a simple cylindrical surface whose inner diameter does not change (nearly or almost) in the axial direction. Further, the outer diameter of the holding screw cylinder 22a is higher than the lower half portion where the male screw portion 39 is formed so as to be screwed into the opening end portion of the sub storage portion 12 and project outside the sub storage portion 12. It is small in the half. Accordingly, the thickness dimension of the set screw cylinder 22a in the radial direction is large in the base half and small in the tip half. With this configuration, the weight of the holding screw cylinder 22a is reduced.

  As described above, the seal ring 29a provided integrally with the cover 30a on the inner peripheral edge of the cover 30a is engaged with the male serration portion 37 of the pinion shaft 6a and the center hole 38 while being serrated. It fits around the intermediate part of the pinion shaft 6a. At this time, the outer fitting operation is performed while elastically expanding the inner diameter of the center hole 38. A stepped surface 41 facing upward is provided at the base end portion (lower end portion) of the male serration portion 37 at the intermediate portion in the axial direction of the pinion shaft 6a. With the inner peripheral edge of the lower surface of the seal ring 29a abutted against the stepped surface 41, the positional relationship between the seal ring 29a and the set screw cylinder 22a becomes appropriate, and at the same time, the cover 30a and the auxiliary storage portion 12 The positional relationship with is appropriate. The outer peripheral edge of the seal lip portion 35 is in sliding contact with the inner peripheral surface of the holding screw cylinder 22a with an appropriate surface pressure over the entire periphery. The cover 30a covers the sliding contact portion between the outer peripheral edge of the seal lip portion 35 and the inner peripheral surface of the holding screw cylinder 22a, and prevents foreign matters such as muddy water from directly falling on the sliding contact portion.

  As described above, in the case of the rack and pinion type steering gear unit 5a of the present example, the seal ring 29a and the cover 30a are integrated by, for example, injection molding an elastic material such as rubber. The seal ring 29a and the cover 30a are externally fitted to the intermediate portion of the pinion shaft 6a, and the outer peripheral edge of the seal ring 29a is applied to the inner peripheral surface of the holding screw cylinder 22a by the elasticity of the extension ring 36. It is in sliding contact with an appropriate surface pressure. For this reason, it is possible to simplify the manufacturing operation, the component management operation, and the assembly operation of the seal ring 29a and the cover 30a, thereby reducing the manufacturing cost. Since the extension ring 36 replaces the garter spring 42 incorporated in the conventional structure shown in FIG. 13, the provision of the extension ring 36 increases the cost compared to the conventional structure. There is no factor.

  Furthermore, in the case of this example, the shape of the set screw cylinder 22a can be simplified, and the manufacturing cost of the set screw cylinder 22a can be kept low. In other words, the inner peripheral surface of the holding screw cylinder 22a is a simple cylindrical surface that does not have a flange portion projecting radially inward and is simply formed with a tapered surface 40 for punching at a portion near the base end. Therefore, it becomes possible to manufacture by forging with a short processing time. Of the inner peripheral surface of the set screw cylinder 22a, the portion axially removed from the tapered surface 40 needs to be a smooth surface in order to make the outer peripheral edge of the seal ring 29a slide. For such a smooth surface, a cored bar (core) whose outer peripheral surface is a smooth surface is used during forging, and the holding screw cylinder is pressed while strongly pressing a part of the material against the outer peripheral surface of the cored bar. It can be easily formed by processing 22a. However, the smooth surface may be formed by machining. Since the area of the part to be machined is limited, the increase in machining cost is limited. Thus, the holding screw cylinder 22a having the required performance can be easily manufactured at low cost and can be reduced in weight. A tapered surface (chamfering) inclined in a direction in which the inner diameter increases toward the upper end edge can be formed at the upper end portion of the inner peripheral surface of the holding screw cylinder 22a. Such a tapered surface functions as a guide surface when the seal ring 29a is inserted. Further, such a tapered surface may be formed as a draft angle during forging, or may be formed by machining after forging.

[Second Example of Embodiment]
3 and 4 show a second example of the embodiment of the present invention. In the case of the steering gear unit 5b of this example, the cross-sectional shape of the upper end portion of the pinion shaft 6b to which the yoke of the universal joint 3 (see FIG. 11) is coupled is an oval shape, and the seal ring 29a and the cover are adapted accordingly. The cross-sectional shape of the central hole 38a of 30a is also an oval type.
Since the structure and operation of the other parts are the same as in the case of the first example of the embodiment described above, the same parts are denoted by the same reference numerals, and redundant description is omitted.

[Third example of embodiment]
FIG. 5 shows a third example of the embodiment of the present invention. In the case of the steering gear unit 5c of this example, the male serration portion 37a is formed only at the upper end portion of the pinion shaft 6c, and the outer peripheral surface of the portion where the seal ring 29b is to be externally fitted at the intermediate portion in the axial direction of the pinion shaft 6c. Is simply a cylindrical surface. Further, a steel cored bar 43 is embedded in a portion closer to the inner diameter of the seal ring 29b, and the seal ring 29b is externally fitted to the intermediate portion in the axial direction of the pinion shaft 6c with a large fitting strength. .
Since the structure and operation of the other parts are the same as in the case of the first example of the above-described embodiment, the same parts are denoted by the same reference numerals, and redundant description is omitted.

[Fourth Example of Embodiment]
FIG. 6 shows a fourth example of the embodiment of the present invention. In the case of the steering gear unit 5d of this example, only the cross-sectional shape of the upper end portion of the pinion shaft 6d is an oval shape, and the outer peripheral surface of the portion where the seal ring 29b is to be fitted at the intermediate portion in the axial direction of the pinion shaft 6d is , Just a cylindrical surface. Further, a steel core 43 is embedded in a portion closer to the inner diameter of the seal ring 29b, and the seal ring 29b is externally fitted with a large fitting strength to the intermediate portion in the axial direction of the pinion shaft 6d.
Since the structure and operation of the other parts are the same as in the case of the second example of the above-described embodiment, the same parts are denoted by the same reference numerals, and redundant description is omitted.

[Fifth to sixth examples of embodiment]
7 to 8 show fifth to sixth examples of the embodiment of the present invention. In the case of the steering gear units 5e and 5f of these two examples, the seal ring 29b is locked in the stepped surface 41 formed on the outer peripheral surface of the intermediate portion of the pinion shafts 6c and 6d and the locking groove on the outer peripheral surface of the intermediate portion. The seal ring 29b is more securely prevented from coming off from the pinion shafts 6c and 6d by being sandwiched between the annular ring retaining ring 44.
Since the configuration and operation of the other parts are the same as those in the third example or the fourth example of the above-described embodiment, the same parts are denoted by the same reference numerals, and redundant description is omitted.

[Seventh to eighth examples of the embodiment]
9 to 10 show seventh to eighth examples of the embodiment of the present invention. In the case of the steering gear units 5g and 5h of these two examples, a small diameter portion 45 having an outer diameter smaller than both side portions in the axial direction is formed in the axially intermediate portion of the pinion shafts 6e and 6f. The seal ring 29a is externally fitted with an interference fit to prevent the seal ring 29a from coming off from the pinion shafts 6e and 6f. The seal ring 29a is the same as that of the first example or the second example of the embodiment described above except that the cross-sectional shape of the center hole is a shape (circular) that can be fitted to the small diameter portion 45 without a gap. The structure is the same as that of the seal ring 29a. Further, as the structure of the seal ring, the structure of the seal ring 29b of the third example or the fourth example of the embodiment described above can be applied.
Since the configuration and operation of the other parts are the same as those in the third example or the fourth example of the above-described embodiment, the same parts are denoted by the same reference numerals, and redundant description is omitted.

The rack and pinion type steering gear unit of the present invention is a so-called column-type electric power unit in which an electric motor 47 or the like for applying auxiliary force is assembled to the steering column 46 as shown in FIG. It can also be implemented in combination with a steering device.
Further, when the present invention is carried out, as a structure for supporting the inner peripheral edge of the lower end portion of the seal ring, a ring-shaped retaining ring having an annular shape can be used instead of the step surface of the intermediate portion of each pinion shaft.

DESCRIPTION OF SYMBOLS 1 Steering wheel 2 Steering shaft 3 Universal joint 4 Intermediate shaft 5, 5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h Steering gear unit 6, 6a, 6b, 6c, 6d, 6e, 6f Pinion shaft 7 Pinion tooth 8 Rack shaft 9 Rack teeth 10 Casing 11 Main storage portion 12 Sub storage portion 13 Spherical joint 14 Tie rod 15 Radial bearing 16 Ball bearing 17 Inner ring 18 Outer ring 19 Inner diameter side step surface 20 Conical stop ring 21 Outer diameter side step surface 22, 22a Suppression Screw cylinder 23 Cylinder cylinder part 24 Pressure roller 25 Sliding block 26 Lid 27 Spring 28 Bellows 29, 29a, 29b Seal ring 30, 30a Cover 31 Inward flange part 32, 32a Fitting part 33, 33a Cover plate part 34, 34a Peripheral wall 35 Seal lip 36 Extension Deployment ring 37,37a male serration portion 38,38a central hole 39 externally threaded portion 40 tapered face 41 stepped surface 42 garter spring 43 metal core 44 retaining ring 45 the small diameter portion 46 a steering column 47 electric motor

Claims (2)

  A casing having a cylindrical main storage portion open at both ends and a cylindrical sub storage portion provided at a twisted position with respect to the main storage portion and open at one end, and rack teeth on the front surface are provided. A rack shaft that is axially displaceable in the storage portion and a pinion tooth formed on the front half portion in the axial direction mesh with the rack teeth, and an axial base half portion of the auxiliary storage portion of the casing. Provided between the pinion shaft disposed in the sub-accommodating portion in a state of projecting outward from the opening, and the outer peripheral surface of the intermediate portion of the pinion shaft and the portion near the opening of the inner peripheral surface of the sub-accommodating portion. A bearing which rotatably supports the pinion shaft in the sub-accommodating portion, and an opening-side end portion of the inner peripheral surface of the sub-accommodating portion. This is a holding screw cylinder that holds down the stepped part A seal ring provided between the inner peripheral surface of the internal thread cylinder and the outer peripheral surface of the intermediate portion of the pinion shaft, and an outer portion of the intermediate portion of the pinion shaft that protrudes from the auxiliary storage portion. In a rack and pinion type steering gear unit including a cover that covers the opening of the storage portion together with the holding screw cylinder, the cover and the seal ring are integrally formed of an elastic material, and the seal The cover is provided in a state in which the cover extends radially outward from a portion protruding from the auxiliary storage portion at an axial end portion of the ring, and the seal ring is externally fitted to an intermediate portion of the pinion shaft. A rack-and-pinion type steering gear unit characterized in that, in a fixed state, an outer peripheral edge is in sliding contact with the inner peripheral surface of the holding screw cylinder over the entire periphery.   The inner circumferential surface of the holding screw cylinder is a cylindrical surface having no flange portion projecting radially inward, and the seal ring is reinforced by an annular cored bar near the inner diameter of the annular elastic material. The rack and pinion type steering gear unit according to claim 1, which is a thing.

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