JP2008018828A - Rack shaft support device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rack shaft support device capable of fixing a plug while properly retaining its clearance with a support member and accomplishing re-utilization of the plug. <P>SOLUTION: A recession part 23 for pouring an adhesive is formed on an edge 30c of an inlet 30 of a retaining hole 8 and a yoke plug 11 is fixed to a housing 9 by the adhesive A poured into the recession part 23 for pouring the adhesive. The adhesive A is not totally interposed between screw surfaces of a male screw part 20 and a female screw part 30b. Pouring of the adhesive A to the recession part 23 for pouring the adhesive is performed from an end surface 30d side of the inlet 30 of the yoke plug 11 after a clearance C between the yoke plug 11 threaded into the retaining hole 8 and the support yoke 10 is adjusted. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rack shaft support device that supports a rack shaft in a rack and pinion type steering device.

  A rack and pinion type steering device is typically provided with a rack shaft support device for removing backlash between the rack and the pinion. In the rack shaft support device, a support yoke that is movable in the depth direction of the holding hole is accommodated in a holding hole formed in the housing, and the rack shaft is slidably supported in the axial direction by the support yoke. The rack shaft is pressed toward the pinion shaft.

  In this rack shaft support device, a yoke plug is screwed into a screw formed on the inner periphery of the inlet of the holding hole, and a biasing member is interposed between the yoke plug and the support yoke so that the support yoke is moved to the rack shaft side. Energized. The yoke plug functions to position the retracted position of the support yoke in the holding hole, and the clearance between the support yoke and the yoke plug is strictly adjusted. After this clearance is set appropriately, the yoke plug is prevented from rotating.

It is desirable that the rotation prevention of the yoke plug is achieved firmly with a small number of parts. For this reason, for example, as shown in Patent Document 1, the flange portion provided on the yoke plug is caulked to achieve rotation prevention of the yoke plug. Also, as shown in Patent Document 1, the yoke plug is prevented from rotating by fixing the yoke plug in the holding hole with an adhesive interposed in the entire screwed portion of the holding hole and the yoke plug. There is also a method.
Japanese Patent Laid-Open No. 9-156514 (3rd, 4th page, 4th, 11th)

However, in the method using caulking, there is a problem that when the yoke plug is removed from the housing, the thread surface is damaged, and the yoke plug cannot be reused.
In addition, in the method in which the adhesive is interposed in the entire screwed portion, the adhesive may start to be cured while the position of the yoke plug is being adjusted. In this case, the clearance between the support yoke and the yoke plug may be increased. Cannot be maintained properly. In addition, it is very difficult to remove the yoke plug from the housing after achieving rotation prevention, and even if the yoke plug can be removed, the thread surface is highly likely to be damaged. The hardened adhesive adheres to the entire screw in an unremovable state. In any case, the yoke plug cannot be reused.

  An object of the present invention is to provide a rack shaft support device capable of fixing a plug while maintaining a proper clearance with a support member, and capable of reusing the plug.

In order to achieve the above object, the invention according to claim 1 is held in a holding hole (8) formed in a housing (9) so as to be movable back and forth in the depth direction (X1) of the holding hole. 7) is slidably engaged with a support member (10) that is slidable in the axial direction and a screw (30b) formed on the inner periphery (30a) of the inlet (30) of the holding hole. A plug (11) for positioning the retracted position; and an urging member (12) interposed between the plug and the support member and urging the support member toward the rack shaft side, the edge of the inlet of the holding hole A recess (23) formed in at least part of the circumferential direction of the portion (30c) and facing the outer periphery (11e) of the end (11d) of the plug with a gap (S), and a plug injected into the recess A rack shaft support device comprising an adhesive (A) that is fixed 2).

In the present invention, since the recess is provided at the edge of the entrance of the holding hole, the adhesive can be injected into the recess while the plug is screwed into the holding hole. In this case, the adhesive can be injected after the clearance is adjusted, whereby the plug can be fixed while maintaining an appropriate clearance.
In addition, the bonding between the plug and the inner periphery of the holding hole is achieved only by the adhesive at the edge of the holding hole, and there is almost no adhesive between the holding hole and the thread surface of the plug. The screw of the plug is not damaged, and the hardened adhesive does not adhere to the entire area of the screw of the plug after removal. Therefore, the plug after removal can be reused. Therefore, the plug can be fixed while the clearance with the support member is properly maintained, and the plug can be reused.

  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.

A preferred embodiment of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a cross-sectional view of a rack and pinion type steering device to which a rack shaft support device according to an embodiment of the present invention is applied. Referring to FIG. 1, the steering device 1 is equipped with a rack shaft support device 2. The pinion shaft 3 is rotatably supported in the pinion housing 6 by a first bearing 4 made of, for example, a ball bearing and a second bearing 5 made of, for example, a cylindrical roller bearing. The rack shaft 7 has an axial length by the rack shaft support device 2 provided in the pinion housing 6 and a bearing member (not shown) provided in the rack housing (not shown) connected to the pinion housing 6. It is slidably supported along the direction (direction orthogonal to the paper surface).

The pinion 3 a of the pinion shaft 3 and the rack 7 a of the rack shaft 7 are meshed with each other in the pinion housing 6. Although not shown, both ends of the rack shaft 7 are connected to the steering wheel via tie rods, and the rack shaft 7 moves in the axial length direction along with the rotation of a steering member such as a steering wheel (not shown). The direction is done.
The rack shaft support device 2 includes a housing 9 having a holding hole 8 formed of a circular hole, and is accommodated in the holding hole 8 so as to be able to advance and retreat in the depth direction X1 of the holding hole 8. A support yoke 10 as a support member that slidably supports the cylindrical member, a cylindrical yoke plug 11 as a sealing member that is screwed into and fixed to the inlet 30 of the holding hole 8, and the support yoke 10 and the yoke plug 11 And a biasing member 12 that biases the support yoke 10 toward the rack shaft 7.

The housing 9 is formed integrally with the pinion housing 6 from a single material, and is disposed on the opposite side of the pinion shaft 3 with the rack shaft 7 therebetween. The pinion housing 6 and the housing 9 are made of aluminum, for example.
A female screw portion 30b is formed on the inner peripheral surface 30a of the inlet 30 of the holding hole 8, and the yoke plug 11 is screwed and fixed to the female screw portion 30b. The yoke plug 11 is made of steel, for example. The yoke plug 11 is fixed to the housing 9 by the bonding of the adhesive A.

  The support yoke 10 has a concave surface 13 formed of an arc surface along the peripheral surface 7b of the rack shaft 7 on the front surface 10a. A sliding contact plate 14 that is in sliding contact with the rack shaft 7 is attached to the concave surface 13. The rear surface 10b of the support yoke 10 is opposed to the front surface 11a of the yoke plug 11 with a predetermined clearance C provided therebetween. The amount of the clearance C is strictly adjusted to 0.1 mm, for example, by adjusting the screwing position of the yoke plug 11.

  A pair of accommodation grooves 16 extending in the circumferential direction and forming an annular shape are formed on the outer peripheral surface 10d of the support yoke 10, and each of the accommodation grooves 16 accommodates an annular elastic member 17 made of, for example, an O-ring. The pair of elastic members 17 elastically contact the inner peripheral surface 8 a of the holding hole 8 and seal between the inner peripheral surface 8 a of the holding hole 8 and the outer peripheral surface 10 d of the support yoke 10. The pair of elastic members 17 elastically supports the support yoke 10 in the radial direction, and prevents the support yoke 10 from rattling.

The biasing member 12 is made of a compression coil spring, for example. The urging member 12 is interposed between the bottom of the recess 10 c formed on the rear surface 10 b of the support yoke 10 and the front surface 11 a of the yoke plug 11.
On the rear surface 11b of the yoke plug 11, for example, a hexagonal tool engaging hole 18 for engaging with a tool for rotating the yoke plug 11 is formed. A cylindrical surface 19 and a male screw portion 20 are formed on the outer peripheral surface 11 c of the yoke plug 11. The cylindrical surface 19 is formed closer to the rack shaft 7 than the male threaded portion 20, and is smaller in diameter than the valley diameter of the male threaded portion 20. The cylindrical surface 19 is formed with an annular accommodating groove 21 extending in the circumferential direction, and an annular sealing member 22 made of, for example, an O-ring is accommodated in the accommodating groove 21.

A feature of the present embodiment is that an adhesive injection recess 23 is formed at the edge 30c of the inlet 30 of the holding hole 8, and the yoke plug 11 is attached with the adhesive A injected into the adhesive injection recess 23. This is a point fixed to the housing 9. For example, as shown in FIG. 3, the adhesive injection recess 23 is formed in two locations at intervals of 180 ° in the circumferential direction of the inlet 30 of the holding hole 8.
1 and 2, each adhesive injection recess 23 is opposed to the outer periphery 11e of the rear end portion 11d of the yoke plug 11 with a gap S therebetween. Since the adhesive injection recess 23 is formed at the edge 30 c of the inlet 30 of the holding hole 8, the adhesive injection recess 23 remains at the entrance of the yoke plug 11 even after the yoke plug 11 is screwed into the holding hole 8. 30 is open to the end face 30d side. The adhesive A is injected into the adhesive injection recess 23 by screwing the yoke plug 11 into the holding hole 8 and adjusting the clearance C with the support yoke 10, and then from the end face 30 d side of the inlet 30 of the yoke plug 11. Do. The bonding between the yoke plug 11 and the holding hole 8 is achieved by the adhesive A injected into the recess 23 for injecting the adhesive. For example, the injection of the adhesive A into the adhesive injection recess 23 is automated, and the adhesive A is continuously injected into each adhesive injection recess 23 by a metering valve (not shown).

  Since the adhesive injection recess 23 is formed at the edge 30c of the inlet 30 of the holding hole 8, when viewed as the entire fitting portion between the male screw portion 20 and the female screw portion 30b, the adhesive A is between them. There is no intervention. In other words, the adhesive A is not interposed between the screw surfaces of the male screw portion 20 and the female screw portion 30b. After joining with the adhesive A, the loosening torque of the yoke plug 11 becomes, for example, 10 N · m or more, and the rotation prevention of the yoke plug 11 is reliably achieved. In this way, it is possible to firmly achieve rotation prevention with a small number of parts.

  The adhesive A is preferably suitable for joining the aluminum housing 9 and the steel yoke plug 11 and has a curing rate in the range of about 30 sec to 40 sec, for example. As the adhesive A, for example, an epoxy system is used. The selection of the type of the adhesive A and the dimension setting of the adhesive injection recess 23 are performed so that the loosening torque of the yoke plug 11 is, for example, 10 N · m or more.

Referring to FIG. 2, the length L of the adhesive injection recess 23 in the depth direction X1 of the holding hole 8 is preferably in the range of 2 mm to 5 mm. When the length L is 2 mm or more, the anti-rotation effect by the adhesive A can be sufficiently achieved, and when the length L is 5 mm or less, re-engagement after disassembly can be easily performed.
Further, the amount of the gap S between the outer periphery 11e of the rear end portion 11d of the yoke plug 11 and the adhesive injection recess 23 between the adhesive injection recesses 23 may be in the range of 2 mm to 5 mm. When the amount of the gap S is 2 mm or more and 5 mm or less, the anti-rotation effect by the adhesive A can be sufficiently achieved.

Referring to FIG. 3, the width W (that is, the circumferential length) of the concave portion 23 for injecting the adhesive with respect to the circumferential direction of the holding hole 8 made of a circular hole is preferably in the range of 4 mm to 5 mm. When the width W is 4 mm or more, the anti-rotation effect by the adhesive A can be sufficiently achieved, and when the width W is 5 mm or less, the male screw portion 20 of the yoke plug 11 is not adversely affected.
When torque more than the loosening torque is applied to the yoke plug 11, the joint between the yoke plug 11 and the housing 9 is released. The yoke plug 11 can be easily removed from the housing 9.

According to this embodiment, the injection of the adhesive A into the adhesive injection recess 23 is performed after the clearance C between the support yoke 10 and the yoke plug 11 is adjusted. As a result, the yoke plug 11 can be fixed to the housing 9 while the clearance C is properly maintained.
Further, the yoke plug 11 and the holding hole 8 are bonded only by the adhesive A of the adhesive injection recess 23 at the edge 30 c of the inlet 30, and the adhesive A is almost between the screw surfaces of the female screw 30 b and the male screw 20. Since there is no interposition, both screw portions 30b, 20 are not damaged when the yoke plug 11 is removed, and the hardened adhesive A hardly adheres to the male screw portion 20 of the yoke plug 11 after removal. Therefore, the yoke plug 11 after removal can be reused. Therefore, the yoke plug 11 can be fixed while the clearance C is properly maintained, and the yoke plug 11 can be reused.

  In the above description, the adhesive injection recess 23 is described as being formed at two positions 180 ° apart in the circumferential direction of the inlet 30 of the holding hole 8, but the adhesive injection recess 23 is 1 It may be formed at a location, may be formed at 3 locations, or may be formed at more locations. When formed in three or more locations, the adhesive injection recesses 23 are preferably formed at equal intervals in the circumferential direction of the inlet 30. In addition, the concave portion for injecting the adhesive may be an annular groove formed over the entire circumference in the circumferential direction of the inlet 30 of the holding hole 8.

  FIG. 4 is a cross-sectional view of a rack and pinion type steering device to which another form of rack shaft support device is applied. In the embodiment shown in FIG. 4, the sealing member 40 can be firmly secured to the housing 9 with a small number of parts as in the embodiment shown in FIGS. 1 to 3. 4, the same components as those shown in FIGS. 1 to 3 are denoted by the same reference numerals as those in FIGS. 1 and 3, and the description thereof is omitted.

With reference to FIG. 4, in this embodiment, the sealing member 40 is press-fitted into the holding hole 8, and the retaining from the housing 9 is achieved. Screwing is not used for fixing the sealing member 40 to the housing 9, and no screw is formed on the outer peripheral surface 43 of the sealing member 40 and the inner peripheral surface 50 a of the inlet 50 of the holding hole 8. .
Referring to FIG. 5, a first cylindrical surface 44 and a second cylindrical surface 45 having different outer diameters are formed on the outer peripheral surface 43 of the sealing member 40. The first cylindrical surface 44 is disposed closer to the rack shaft 7 than the second cylindrical surface 45. The first cylindrical surface 44 is formed with a smaller diameter than the second cylindrical surface 45, and the outer diameter D 1 of the first cylindrical surface 44 is set smaller than the outer diameter D 2 of the second cylindrical surface 45. Of the outer peripheral surface 43 of the sealing member 40, an annular accommodating groove 41 is formed in the boundary portion between the first cylindrical surface 44 and the second cylindrical surface 45, forming an annular shape. An annular seal member 42 is accommodated.

  FIG. 6 is a cross-sectional view of a main part showing a press-fitting process of the sealing member into the housing. (A) shows the state before press-fitting, and (b) shows the state after press-fitting. Referring to FIG. 6, the inlet 50 of the holding hole 8 is enlarged in diameter so as to have a larger diameter than the remaining part of the holding hole 8. The inner diameter D3 of the inlet 50 is set to be larger than the outer diameter D1 of the first cylindrical surface 44 and smaller than the outer diameter D2 of the second cylindrical surface 45 (D1 <D3 <D2). An annular step portion 51 is formed between the inner peripheral surface 50 a of the inlet 50 of the holding hole 8 and the inner peripheral surface 8 a of the remaining portion of the holding hole 8. The length E (the distance between the end surface 50b of the inlet 50 and the annular step portion 51) of the portion of the holding hole 8 where the diameter of the inlet 50 is enlarged takes into account the clearance C between the sealing member 40 and the support yoke 10. , Is set to the required length.

  The sealing member 40 is inserted from the inlet 50 of the holding hole 8. Since the outer diameter D1 of the first cylindrical surface 44 is smaller than the inner diameter D3 of the inlet 50 (D1 <D3), the sealing member 40 is guided by the first cylindrical surface 44 and smoothly enters the holding hole 8. Inserted. The second cylindrical surface 45 is inserted into the inlet 50 of the holding hole 8 following the first cylindrical surface 44, but the outer diameter D2 of the second cylindrical surface 45 is larger than the inner diameter D3 of the inlet 50. (D2> D3), the second cylindrical surface 45 is press-fitted into the inlet 50. The sealing member 40 is pushed in until the front surface 40a comes into contact with the annular step portion 51 (see FIG. 6B). In this state, the clearance C between the sealing member 40 and the support yoke 10 is set to a predetermined amount. Further, in this state, a sufficiently large contact pressure is generated between the second cylindrical surface 45 of the sealing member 40 and the inner peripheral surface 50a of the inlet 50, whereby the sealing member 40 is removed. Stop is achieved.

In this embodiment, the step of threading the sealing member 40 and the inner peripheral surface 50a of the inlet 50 of the holding hole 8 is not necessary, so that the cost can be reduced. This form is useful when the accuracy of the clearance C between the sealing member 40 and the support yoke 10 is not strictly required.
In addition, this invention is not limited to the said embodiment, A various change can be given in the claim of this invention.

1 is a cross-sectional view of a rack and pinion type steering device to which a rack shaft support device of an embodiment of the present invention is applied. It is an expanded sectional view of the principal part of a yoke plug and a housing. It is a figure which shows the structure of the yoke plug and the housing seen from the arrow B direction of FIG. It is sectional drawing of the rack and pinion type steering device to which the rack shaft support device of another form was applied. It is an expanded sectional view of the important section of a sealing member. It is principal part sectional drawing which shows the press injection process to the housing of a sealing member. (A) shows the state before press-fitting, and (b) shows the state after press-fitting.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Steering device, 2 ... Rack shaft support device, 7 ... Rack shaft, 8 ... Holding hole, 9 ... Housing, 10 ... Support yoke (support member), 11 ... Yoke plug (plug), 11d ... Rear end (end) Part), 11e ... outer periphery, 12 ... urging member, 23 ... concave portion (concave portion) for injecting adhesive, 30 ... inlet, 30a ... inner peripheral surface (inner periphery), 30b ... female screw portion (screw), 30c ... edge , A: adhesive, S: gap, X1: depth direction of holding hole

Claims (1)

A support member that is held in a holding hole formed in the housing so as to be movable back and forth in the depth direction of the holding hole, and that supports the rack shaft so as to be slidable in the axial direction;
A plug that is screwed into a screw formed on the inner periphery of the inlet of the holding hole and positions the retracted position of the support member;
A biasing member interposed between the plug and the support member and biasing the support member toward the rack shaft;
A recess formed at least in the circumferential direction of the edge of the inlet of the holding hole and facing the outer periphery of the end of the plug;
An apparatus for supporting a rack shaft, comprising: an adhesive that is injected into the recess and fixes the plug.

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