JP2008254591A - Pipe mounting structure for power cylinder, and vehicular steering device provided with this - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive pipe mounting structure for a power cylinder, which connects the pipe by a simple structure. <P>SOLUTION: A swelled part 30 swelled in a radial direction R1 of a cylinder tube 9a is integrally formed with the cylinder tube 9a by a single material. The swelled part 30 is provided with first and second surfaces 31, 32 crossing to each other. A first hole 34 penetrating through the swelled part 30 in the radial direction R1 and forming an opening 33 on the first surface 31 is liquid-tightly closed by a plug 37. The pipe 17 is thread-fastened to a second hole 35 branched from a midway part 34a of the first hole 34. A flange 39 of the plug 37 is pressed to an edge part 33a of the opening 33 of the first hole 34 to become a relax-stop of the plug 37. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a power cylinder piping mounting structure and a vehicle steering apparatus including the same.

In the hydraulic power steering apparatus, a hydraulic control valve is provided so that one of a pair of oil chambers of the power cylinder is connected to a hydraulic pump and the other is connected to an oil tank. One end of the pipe for communicating the hydraulic control valve and the oil chamber of the power cylinder may be connected to the cylinder tube of the power cylinder through an elbow joint.
When both the cylinder tube and the elbow joint are made of iron, the elbow joint is generally fixed to the cylinder tube by welding (see, for example, Patent Document 1).

Moreover, it replaces with an elbow joint and the structure using the curved piping bent by the L-shape shape is proposed (for example, refer patent document 2, 3).
JP-A-3-246164 JP 59-226703 A Japanese Patent Laid-Open No. 9-86428

By the way, in recent years, it has been demanded to use aluminum as a material of the cylinder tube, and in that case, fixing by welding is difficult. In the case of welding, the cost is high. On the other hand, bent pipes are also expensive to manufacture.
The present invention has been made in view of the above problems, and an object thereof is to provide an inexpensive power cylinder pipe mounting structure capable of connecting pipes with a simple structure and a vehicle steering apparatus including the same. .

  In order to achieve the above object, the present invention provides a power cylinder piping mounting structure (S) for connecting a pipe (17) to a cylinder tube (9a) of a power cylinder (9). A bulging portion (30) formed integrally with the material and bulging in the radial direction (R1) of the cylinder tube, a plug (37), and a sealing member (44) for sealing between the plug and the bulging portion ), And the bulging portion passes through the first surface (31), the second surface (32) intersecting the first surface, and the bulging portion in the radial direction of the cylinder tube. A first hole (34) that forms an opening (33) on the first surface, and a second part that branches from a midway part (34a) of the first hole in a direction (X1) intersecting the first hole. A second hole (35) penetrating the surface of the second pipe, and the pipe is screwed into the second hole. The first hole is liquid-tightly closed by the plug, and the plug is provided with a flange (39) that is pressed against the edge (33a) of the opening of the first hole. It is characterized by being.

  In the present invention, the bulging portion is integrally formed with the cylinder tube and a single material, and intersects the first hole from the middle portion of the first hole penetrating the bulging portion in the radial direction of the cylinder tube. The pipe is screwed into the second hole that branches in the direction. Therefore, in order to avoid interference between the piping and other vehicle parts, an elbow joint is used when connecting the end of the piping from a direction other than the radial direction of the cylinder tube (for example, a direction parallel to the axial direction of the cylinder tube). This eliminates the need for the welding process, which has been necessary in the past, and can reduce the manufacturing cost.

  On the other hand, the first hole is a hole necessary for processing in order to form a bent oil passage in the bulging portion. When the plug for closing the first hole is screwed into the first hole, the flange provided on the plug is pressed against the edge of the opening of the first hole, and serves as a loosening prevention portion for the plug. Because it functions, the plug will not loosen. Therefore, a lock nut or the like is not required for fixing the plug, and the sealing performance can be enhanced at a low cost with a simple structure.

The outer peripheral surface of the plug is provided with a thread portion (40) and a circumferential groove (43) provided between the thread portion and the flange, and the sealing member is accommodated in the circumferential groove. When an annular elastic member is included, it is preferable in that the sealing performance can be further improved.
Moreover, it is preferable that piping is attached to the cylinder tube of the power cylinder that generates the steering assist force using the power cylinder piping mounting structure.

  In the above description, the alphanumeric characters in parentheses represent reference numerals of corresponding components in the embodiments described later, but the scope of the claims is not limited by these reference numerals.

Preferred embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a partially broken side view of a main part of a hydraulic power steering device as a vehicle steering device to which a power cylinder piping mounting structure according to an embodiment of the present invention is applied. Referring to FIG. 1, a power steering apparatus 1 includes a rack and pinion mechanism with hydraulic power assist including a rack shaft 2 having rack teeth 2a and a pinion (not shown).

The rack shaft 2 is slidably supported in the axial direction in a cylindrical rack housing 3 extending in the left-right direction of the vehicle body and a gear housing 4 connected to one end of the rack housing 3. Both ends of the rack shaft 2 are connected to tie rods 5 respectively connected to front wheels (not shown) via ball joints 6.
A rod 7 is formed on a part of the rack shaft 2, and a steering assist is provided by sealing the rod 7 and the rack housing 3 surrounding the rod 7 with a pair of left and right rod seals 8, 8. A power cylinder 9 for generating force is configured. Accordingly, the cylinder tube 9 a of the power cylinder 9 is configured by a part of the rack housing 3.

The rod seal 8 on the gear housing 4 side is press-fitted into a position where it abuts against the end of the support cylinder portion 10 in the cylinder tube 9a. The other rod seal 8 is positioned in contact with a rack bush 21 fixed to the end of the cylinder tube 9a.
The gear housing 4 includes a support cylinder portion 10 that is press-fitted and connected to one end of the rack housing 3, and a main housing 11 that extends obliquely upward in a manner that is oblique to the support cylinder portion 10.

One end of the input shaft 12 of the power steering 1 protrudes from the main housing 11 and is connected to a steering member 13 including a steering wheel so as to be integrally rotatable. Although not shown, the main housing 11 accommodates an output shaft that forms a pinion, and a torsion bar that connects the input shaft 12 and the output shaft so that they can be displaced relative to each other.
Also, in the upper part of the main housing 11, the pressure oil from the hydraulic pump P is separated from each other by the piston 14 based on the relative angular displacement between the input and output shafts, and left and right oil chambers 15, 16 of the power cylinder 9. And a control valve C for returning the oil from the other oil chamber to the oil tank T. The hydraulic control device A that controls supply and discharge of hydraulic pressure to and from the power cylinder 9 includes a housing H formed from an upper portion of the main housing 11 and a control valve C built in the housing H.

  The oil chambers 15 and 16 of the power cylinder 9 are connected to the control valve C via corresponding pipes 17 and 18, respectively. Specifically, one pipe 17 is formed in the first port 19 formed on the peripheral surface of the housing H of the oil control device A and communicated with the control valve C, and the cylinder tube 9a of the power cylinder 9 to form an oil chamber. 15 communicates with the second port 20 that communicates with the second port 20. The end portion 17a of the pipe 17 is connected to a bulging portion 30 formed integrally with the cylinder tube 9a from a single material, and the pipe 17 mounting structure of the power cylinder according to the present embodiment is provided by the pipe 17 mounting structure. Structure S is constructed.

The other pipe 18 is formed in the peripheral surface of the housing H of the oil control device A and communicates with the control valve C, and is formed in the cylinder tube 9 a of the power cylinder 9 and communicates with the oil chamber 16. The second port 23 is in communication.
Referring to FIG. 2, cylinder tube 9a of power cylinder 9 is formed of a material containing aluminum. The bulging portion 30 is formed in the cylinder tube 9a. The bulging portion 30 is formed by bulging a part in the circumferential direction of the peripheral wall 9b of the cylinder tube 9a so as to protrude in the radial direction R1 of the cylinder tube 9a.

  The bulging portion 30 includes a first surface 31 that is orthogonal or substantially orthogonal to the radial direction R1 of the cylinder tube 9a, and a second surface 32 that intersects the first surface 31, for example, is orthogonal. The bulging portion 30 includes a first hole 34 that penetrates the bulging portion 30 in the radial direction R1 of the cylinder tube 9a and forms an opening 33 in the first surface 31, and the first hole 34. A second hole 35 that branches from the midway part 34 a in the direction X <b> 1 intersecting the first hole 34 and penetrates the second surface 32 is provided.

  A plug fitting portion 36 having a larger diameter than the remaining portion of the first hole 34 is formed at the inlet of the first hole 34, and a plug 37 is liquid-tight in the plug fitting portion 36. Is fitted. Specifically, the plug 37 includes a cylindrical plug body 38 whose front end 38 a is closed, and an annular flange 39 extending radially outward from the rear end 38 b of the plug body 38. The flange 39 functions as a loosening prevention portion of the plug 37 by being pressed by the edge portion 33 a of the opening 33 of the first surface 31 of the bulging portion 30.

On the outer peripheral surface of the plug main body 38, a threaded portion 40 is formed at a portion on the front end side. The screw portion 40 is screwed to a screw portion 41 formed in the plug fitting portion 36.
On the other hand, on the outer peripheral surface of the plug main body 38, a large-diameter portion 42 having a larger diameter than the screw portion 40 is formed at a portion between the flange 39 and the screw portion 40. A circumferential groove 43 extending in the circumferential direction is formed in the large diameter portion 42, and an annular elastic member 44 as a sealing member made of, for example, an O-ring is accommodated and held in the circumferential groove 43. The elastic member 44 as a sealing member is interposed between the cylindrical surface 45 formed in the plug fitting portion 36 and the outer peripheral surface of the plug main body 38, and seals between the two.

  An intermediate flange 48 formed by bulging is provided at the end portion 17 a of the pipe 17 connected to the second hole 35. A portion at the end of the intermediate flange 48 is a flare portion 49 that is expanded toward the end. An O-ring 50 is fitted to the flare portion 49 so as to be in contact with the intermediate flange 48. In addition, a metal fastener 51 is fitted to the pipe 17 so as to be freely rotatable on the peripheral surface of the pipe 17 while being prevented from being detached by the intermediate flange 48. On the outer periphery of the fastener 51, there are provided a screw portion 52 and a tool engaging portion 53 having a polygonal cross section.

  In the second hole 35, an accommodating portion 54 for connecting the end portion 17a of the pipe 17 is formed. The accommodating part 54 has a first accommodating part 56 having a screw part 55 screwed to the threaded part 52 of the fastener 51 on the inner periphery, and a smaller diameter than the first accommodating part 56, and the first accommodating part 56 and includes a second housing portion 57 for housing the flare portion 49 of the pipe 17. A chamfered portion 59 is formed on the inner periphery of the annular stepped portion 58 formed between the first accommodating portion 56 and the second accommodating portion 57, and between the chamfered portion 59 and the base portion of the flare portion 49. The O-ring 50 is elastically sandwiched between the chamfered portion 59 and the flare portion 49 by the O-ring 50.

  According to the present embodiment, the bulging portion 30 is integrally formed of a single material with the cylinder tube 9a, and the middle of the first hole 34 that penetrates the bulging portion 30 in the radial direction R1 of the cylinder tube 9a. The end portion 17a of the pipe 17 is screwed to the second hole 35 branched from the portion 34a in the direction X1 intersecting the first hole 34. Therefore, in order to avoid interference between the pipe 17 and other vehicle parts, the end 17a of the pipe 17 is connected from a direction other than the radial direction R1 of the cylinder tube 9a (for example, a direction parallel to the axial direction of the cylinder tube 9a). At this time, it is not necessary to use an elbow joint, and therefore a welding process that has been conventionally required can be eliminated, and as a result, the manufacturing cost can be reduced.

  On the other hand, the first hole 34 of the bulging portion 30 is a hole necessary for processing in order to form a bent oil passage in the bulging portion 30. When the plug 37 for closing the first hole 34 is screwed into the screw portion 41 of the plug fitting portion 36 of the first hole 34, the flange 39 provided in the plug 37 is It is pressed against the edge 33 a of the opening 33 of the hole 34. As a result, since the flange 39 functions as a loosening prevention portion for the plug 37, the plug 37 is not loosened. Therefore, it is not necessary to use a lock nut or the like for fixing the plug 37, and the sealing performance can be enhanced at a low cost with a simple structure.

Furthermore, since the elastic member 44 interposed between the cylindrical surface 45 of the plug fitting portion 36 of the first hole 34 and the outer peripheral surface of the plug 37 is used, the sealing performance can be further improved.
Since it is not necessary to use an elbow joint or welding, a remarkable effect can be obtained particularly in combination with the case where the cylinder tube 9a is formed of a material containing aluminum as in the present embodiment.

  In the present embodiment, the present invention is applied to the mounting of the power cylinder piping of the hydraulic power steering apparatus, but the so-called steer-by-wire system vehicle steering apparatus in which the mechanical connection between the steering member and the steering mechanism is broken. The present invention can also be applied to a structure for attaching a power cylinder pipe as a steering actuator. In addition, various modifications can be made within the scope of the claims of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially cutaway front view of a hydraulic power steering as a vehicle steering device to which a power cylinder piping mounting structure according to an embodiment of the present invention is applied. It is sectional drawing of the piping mounting structure of a power cylinder.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Power steering apparatus, 9 ... Power cylinder, 9a ... Cylinder tube, 9b ... Peripheral wall, 17 ... Piping, 17a ... End part, S ... Pipe mounting structure of a power cylinder, 30 ... Swelling part, 31 ... 1st surface 32 ... second surface, 33 ... opening, 33a ... edge of opening, 34 ... first hole, 35 ... second hole, 36 ... plug fitting portion, 37 ... plug, 38 ... plug body, 39 ... Flange, 40, 41 ... Threaded portion, 43 ... Circumferential groove, 44 ... Ring-shaped elastic member (sealing member), 45 ... Cylindrical surface, R1 ... Radial direction of cylinder tube, X1 ... Direction intersecting the first hole

Claims (3)

In the power cylinder piping mounting structure for connecting the piping to the cylinder tube of the power cylinder,
A bulging portion formed integrally with the cylinder tube from a single material and bulging in the radial direction of the cylinder tube;
A plug,
A sealing member for sealing between the plug and the bulging portion,
The bulging portion includes a first surface, a second surface that intersects the first surface, and a first surface that penetrates the bulging portion in the radial direction of the cylinder tube and forms an opening in the first surface. A hole, and a second hole that branches from the middle of the first hole in a direction intersecting the first hole and penetrates the second surface;
The pipe is screwed to the second hole,
The first hole is liquid-tightly closed by the plug,
A power cylinder pipe mounting structure, wherein the plug is provided with a flange that is pressed against an edge of the opening of the first hole. In claim 1, the outer peripheral surface of the plug is provided with a threaded portion and a circumferential groove provided between the threaded portion and the flange,
The power cylinder pipe mounting structure, wherein the sealing member includes an annular elastic member accommodated in the circumferential groove.   A vehicle steering apparatus, wherein a pipe is attached to a cylinder tube of a power cylinder that generates a steering assist force using the pipe attachment structure according to claim 1.

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