JP2008132845A - Connecting structure of joint yoke and shaft in steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To position a joint yoke and a shaft in the circumferential direction in high precision by strengthening regulating force of a slit engaging plate in the rotating direction before the shaft and the joint yoke are serration-engaged with each other. <P>SOLUTION: A structure is constituted to serration-connect the shaft 29 forming serration 41b, 41c on an outer periphery of its fore end part and the joint yoke 40 made into a cutout cylindrical shape provided with a slit in the axial direction for positioning and forming serration 43 on an inner periphery to each other while positioning them in the circumferential direction by a guide member 46 furnished with a slit engaging plate 48 to be engaged with the slit in the axial direction. The guide member 46 is furnished with a connecting part 47 connected to the fore end part of the shaft 29 with its rotation regulated, and the slit engaging plate 48 is formed projected from the outer periphery of the connecting part 47 and extends in the axial direction toward the base end side along the outer periphery of the shaft 29. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a joint yoke and shaft coupling structure in a steering device, and more particularly to a technique for positioning in the circumferential direction when coupling a joint yoke and a shaft.

As a coupling structure of a joint yoke and a shaft in a conventional steering device, for example, the one described in Patent Document 1 is known.
The structure of Patent Document 1 is connected to a pinion shaft that protrudes from the gear housing of the steering gear unit and forms serrations on the outer periphery of the tip, and a member on the steering wheel side, and an axial slit for tightening In order to set the steering wheel in the neutral state and set the steering gear unit in the straight-running state when the serration is coupled with the joint yoke with the serration on the inner periphery, the positioning guide A joint yoke and a pinion shaft are serrated and connected using a member (referred to as a guide tip in Patent Document 1).

The positioning guide member includes an annular first engaging portion having serrations formed on the inner surface, a thin plate-shaped second engaging portion formed in an axial direction from the first engaging portion, and the second engaging portion. It is a member provided with the notch annular 3rd engaging part formed in the front-end | tip of a part.
Then, the first engagement portion is serrated and engaged with the base end side of the serration formed on the pinion shaft set in the straight traveling state, and the third engagement portion is fitted to the outer periphery of the engagement protrusion formed on the tip end of the pinion shaft. In this state, the guide member is integrated with the pinion shaft. Next, with the steering wheel set to the neutral position, the joint yoke is pushed toward the pinion shaft while engaging the axial slit with the second engagement portion of the guide member, so that the circumference of the pinion shaft and the joint yoke is increased. Serration coupling is performed while positioning in the direction is performed.
No. 6-24300

  However, in Patent Document 1 described above, the notched annular third engaging portion disposed at a position spaced apart in the axial direction with respect to the first engaging portion serrated and engaged with the pinion shaft has a rotational force that restricts the rotational force. The pinion shaft is fitted to the engagement protrusion at the tip of the pinion shaft in a weak state. For this reason, even if the axial slit of the joint yoke is engaged with the second engaging portion of the guide member, the joint yoke is slightly rotated before the serrations of the pinion shaft and the joint yoke are engaged with each other. When the torsional force is applied to the pinion shaft, the second engagement portion is twisted by the rotation of the third engagement portion, and there is a possibility that the joint yoke is serrated with the circumferential position of the joint yoke being different. is there.

  Therefore, the present invention has been made paying attention to the above-mentioned unsolved problems of the conventional example, and by strengthening the regulating force in the rotational direction of the slit engagement plate before the shaft and the joint yoke are serrated, It is an object of the present invention to provide a joint yoke / shaft coupling structure in a steering apparatus capable of positioning the yoke and the shaft in the circumferential direction with high accuracy.

  In order to achieve the above object, the joint yoke and shaft coupling structure in the steering device according to claim 1 has a shaft with serrations formed on the outer periphery of the tip, and a notched cylindrical shape provided with a positioning axial slit. A joint yoke and shaft coupling structure in a steering device in which a joint yoke having serrations formed on the inner circumference is serrated while being positioned in the circumferential direction by a guide member having a slit engaging plate that engages with the axial slit. The guide member includes a connecting portion that is connected to the tip end portion of the shaft so that rotation is restricted, and the slit engaging plate is formed to protrude from the outer periphery of the connecting portion, and the outer periphery of the shaft Is extended in the axial direction toward the base end side.

According to a second aspect of the present invention, in the coupling structure of the joint yoke and the shaft in the steering device according to the first aspect, the connecting portion is an annular member, and is press-fitted into a small-diameter protruding portion protruding from the tip of the shaft. It is fitted in the state.
According to a third aspect of the present invention, in the coupling structure of the joint yoke and the shaft in the steering device according to the first aspect, the connecting portion is an annular member having serrations formed on the inner surface, and protrudes from the tip of the shaft. Serrations are formed on the outer periphery of the small-diameter protruding part, and the serrations of the connecting part and the serrations of the protruding part are serrated.

According to a fourth aspect of the present invention, in the joint yoke and shaft coupling structure according to the first aspect of the present invention, the connecting portion is a member provided with a convex portion, and the convex portion is provided at the tip of the shaft. It is fitted in the recessed part in a press-fit state.
According to a fifth aspect of the present invention, in the joint yoke / shaft coupling structure according to the first aspect of the present invention, the connecting portion is a member having a convex portion formed with serrations on the outer periphery, and the tip of the shaft Serrations are formed on the inner surfaces of the concave portions provided in the upper surface, and the serrations of the convex portions and the serrations of the concave portions are serrated and coupled.

According to a sixth aspect of the present invention, in the joint yoke / shaft coupling structure according to the first aspect of the present invention, the connecting portion is an annular member, and a female screw is provided on the inner surface of the recess provided at the tip of the shaft. At the same time, the male screw of the connecting bolt inserted through the connecting portion is screwed into and connected to the female screw of the recess.
Further, the invention according to claim 7 is the joint yoke and shaft coupling structure in the steering device according to any one of claims 1 to 6, and extends along the outer periphery of the shaft of the slit engagement plate. Serrations that are serration-coupled to the serrations formed on the shaft were formed on the surface.

  Furthermore, the invention according to claim 8 is the joint yoke and shaft coupling structure in the steering device according to any one of claims 1 to 7, wherein the tip end side and the base end side of the slit engagement plate are inclined. A portion or a rounded portion was provided so that no corners existed.

  According to the joint yoke / shaft coupling structure in the steering device according to the present invention, the tip end side of the slit engagement plate is formed to protrude from the outer periphery of the connecting portion that is connected to the tip end portion of the shaft so that its rotation is restricted. Therefore, the structure has a strong restricting force in the rotational direction together with the connecting portion, and the tip side of the slit engagement plate is not twisted even if the joint yoke rotates slightly and a twisting force acts. For this reason, before the serration of the joint yoke engages with the serration of the input shaft, the axial slit for positioning is engaged with the distal end side of the slit engaging plate having a strong rotational regulating force to ensure that the joint yoke is engaged. Since guided, the positioning of the joint yoke and the shaft in the circumferential direction can be performed with high accuracy.

Hereinafter, the best mode for carrying out the present invention (hereinafter referred to as an embodiment) will be described in detail with reference to the drawings.
1 is an overall configuration diagram showing a steering device according to the present invention, FIG. 2 is a cross-sectional view of a main part of a steering gear according to the present invention, and FIG. 3 is a diagram showing a coupling structure of an input shaft and a joint yoke of a rack and pinion mechanism, 4 is a view taken along the line AA in FIG. 3, FIG. 5 is a view showing an exploded state of the input shaft and the joint yoke, and FIG. 6 is a view showing a guide member coupled to the input shaft.

  A steering device 10 in FIG. 1 includes a steering column 12 that supports a steering shaft 11 so as to be rotatable. A steering wheel (not shown) is attached to the upper end of the steering shaft 11, and an intermediate shaft 15 is connected to the lower end of the steering shaft 11 via a universal joint 14. A steering gear 17 is connected to the lower end of the intermediate shaft 15 via a universal joint 16. A later-described rack shaft 27 of the steering gear 17 is connected to left and right steered wheels (not shown) via tie rods 18.

  1 is a steering gear case, and the steering gear case 21 holds a rack and pinion mechanism 23 and a pinion assist type electric assist mechanism 24. As shown in FIG. 2, the rack and pinion mechanism 23 includes a pinion shaft 25 that forms a pinion 24, and a rack shaft 27 that forms a rack 26 that meshes with the pinion 24.

One end of the rack shaft 27 is connected to one of the left and right steering wheels via a tie rod 18, and the other end of the rack shaft 27 is connected to the other left and right steering wheels via a tie rod 18. Yes.
One end of a torsion bar 28 is connected to the pinion shaft 25. The torsion bar 28 is inserted into the shaft hole 29a of the cylindrical input shaft 29 disposed coaxially with the pinion shaft 25, and the other end is internally fitted in the shaft hole 29a. The input shaft 29 is coupled to a joint yoke 40 described later of the universal joint 16. Reference numeral 30 denotes a rack guide that presses the rack shaft 27 against the pinion 24.

  As shown in FIGS. 1 and 2, the electric assist mechanism 24 includes an electric motor 31 that is driven and controlled by a power assist control device (not shown), a worm 33 fixed to a shaft 32 of the electric motor 31, and a pinion The worm wheel 34 is fixed to the outer periphery of the shaft 25 and meshes with the worm 33. A member indicated by reference numeral 35 is a torque sensor that detects a steering torque from the amount of twist of the torsion bar 28, and members indicated by reference numerals 36 and 37 are bearings that rotatably support the pinion shaft 25.

  When the driver steers the steering wheel in either the left or right direction, the torque sensor 35 detects the steering torque, thereby receiving the drive current from the power assist control device and starting the electric motor 31. As a result, the worm 33 fixed to the shaft 32 of the electric motor 31 rotates, and the rotational force is transmitted to the pinion shaft 25 via the worm wheel 34. When the pinion shaft 25 rotates, the rack shaft 27 in which the rack 26 meshes with the pinion 24 is driven in the axial direction, and the left and right steering wheels connected to the tie rod 18 are steered.

As shown in FIG. 5, the upper end of the input shaft 29 (the right end portion in FIG. 5) protrudes from the upper end opening of the steering gear case 21 by a predetermined length. Serrations 41b and 41c are formed on the upper and lower sides of an annular groove 41a having an arcuate cross section.
As shown in FIGS. 4 and 5, the joint yoke 40 of the universal joint 16 is formed in a notched cylindrical shape having a tightening slit 42, and engages with serrations 41 b and 41 c of the input shaft 29 on its inner surface. A serration 43 is formed, and a through hole 45 through which the tightening bolt 44 is inserted is formed in a direction penetrating the tightening slit 42.

  Further, as shown in FIG. 5, the upper end (the right end portion in FIG. 5) of the torsion bar 28 inserted through the shaft hole 29 a of the input shaft 29 is the opening (input shaft) of the shaft hole 29 a of the input shaft 29. 29 is projected with a predetermined length from the tip of 29). A positioning guide member 46 is fixed to the cylindrical protruding portion 28a of the torsion bar 28 protruding from the opening of the shaft hole 29a of the input shaft 29.

As shown in FIG. 6, the guide member 46 is formed by projecting from the outer periphery of the connecting portion 47 and an annular connecting portion 47 having an inner diameter that fits into the protruding portion 28 a in a press-fit state. And a slit engaging plate 48 that extends into one of the axial directions and engages with the fastening slit 42 of the joint yoke 40.
The slit engagement plate 48 has a shape in which the outer periphery on the distal end side is an inclined portion 48a whose height gradually increases toward the proximal end side, and the outer periphery on the proximal end side is an arcuate round portion 48b having a predetermined radius. Yes.

Further, the slit engaging plate 48 is cut out at a portion facing the annular groove 41 a of the input shaft 29, and a through hole 49 through which the tightening bolt 44 is inserted is formed.
Further, serrations 50 a and 50 b that are serrated and coupled to serrations 41 b and 41 c formed on the outer periphery of the input shaft 29 are formed on the lower surface of the slit engagement plate 48 that contacts the outer periphery of the input shaft 29.

Next, the operation and effect of the steering device of this embodiment will be described.
When the guide member 46 is attached to the input shaft 29, first, the steering gear 17 is set in a straight traveling state, and then, as shown in FIGS. 5 and 6, the slit engaging plate 48 extends in the axial direction at a predetermined circumferential position. While aligning so as to exist, the connecting portion 47 is fixed to the outer periphery of the protruding portion 28a of the torsion bar 28 by press fitting, and the serrations 50a and 50b formed on the lower surface of the slit engaging plate 48 are connected to the serration 41b of the input shaft 29, The guide member 46 is attached to the input shaft 29 so that the slit engaging plate 48 protrudes from the outer periphery of the connecting portion 47 and extends toward the proximal end side of the input shaft 29 by being serrated to 41c.

  Next, the joint yoke 40 is assembled to the input shaft 29 so that when the steering wheel is set to the neutral position, the rotational slits 42 of the joint yoke 40 and the slit engaging plate 48 of the guide member 46 coincide with each other. Therefore, when the joint yoke 40 is pushed in the axial direction of the input shaft 29 as it is, the joint yoke 40 is guided while the slit 42 for fastening is engaged with the slit engaging plate 48.

  Here, immediately before the serration 43 of the joint yoke 40 engages with the serration 41 b of the input shaft 29, the front end side of the slit engaging plate 48 engages with the tightening slit 42. At this time, when the joint yoke 40 rotates slightly and the joint yoke 40 is pushed into the input shaft 29 at a position different from the normal circumferential position, a twisting force is applied to the distal end side of the slit engaging plate 48. Works. However, the distal end side of the slit engagement plate 48 of the present embodiment is located on the outer periphery of the connecting portion 47 that is fitted in the protruding portion 28 a in a press-fitted state and is restricted from rotating, and together with the connecting portion 47, Strong regulatory power. For this reason, even if the joint yoke 40 rotates slightly and a torsional force acts on the front end side of the slit engaging plate 48, the front end side of the slit engaging plate 48 having a strong restricting force in the rotating direction is not twisted. By applying a reaction force in the opposite direction to the direction in which the twisting force acts on the raising slit 42, the joint yoke 40 is returned to the normal circumferential position.

  When the joint yoke 40 is further pushed in the axial direction of the input shaft 29, the slit engaging plate 48 is serrated and connected to the serrations 41 b and 41 c of the input shaft 29 by the serrations 50 a and 50 b formed on the lower surface. The joint yoke 40 that is guided by engaging the slit 42 for tightening with the slit engaging plate 48 is extended in the axial direction at a predetermined circumferential position with a stronger directional regulation force. The serration 43 is serrated and engaged with the regular serrations 41b and 41c of the input shaft 29, and finally, the positioning in the circumferential direction is accurately performed with respect to the input shaft 29 and the serration is coupled.

When the circumferential positioning of the input shaft 29 and the joint yoke 40 is completed and the serration coupling is performed, the annular groove 41a formed in the input shaft 29, the through hole 45 formed in the joint yoke 40, and the slit of the guide member 46 The through holes 49 formed in the engagement plate 48 coincide with each other on the same axis.
When the tightening bolt 44 is inserted into the through holes 45 and 49 and the annular groove 41a and screwed so that the interval between the tightening slits 42 is narrowed, the slit engaging plate 48 is sandwiched in the tightening slit 42, The input shaft 29 is clamped and clamped in the joint yoke 49, so that the joint yoke 40 is firmly connected to the input shaft 29 in a state in which its rotational direction and axial movement are completely prevented.

  Therefore, according to the present embodiment, the distal end side of the slit engaging plate 48 is positioned on the outer periphery of the connecting portion 47 that is connected to the protruding portion 28a with the rotation being restricted, and together with the connecting portion 47, the restricting force in the rotation direction is strong. Due to the structure, even if the joint yoke 40 is rotated slightly and a torsional force is applied, the tip end side of the slit engagement plate 48 is not twisted. Since the joint yoke 40 is reliably guided by engaging the joint yoke 40, the joint yoke 40 can be positioned with respect to the input shaft 29 in the circumferential direction with high accuracy.

  In addition, the entire slit engaging plate 48 is serrated by serrations 50a and 50b formed on the lower surface thereof to serrations 41b and 41c of the input shaft 29, thereby strengthening the rotational restricting force in the axial direction at a specified circumferential position. Since the joint yoke 40 guided by the slit engaging plate 48 is extended, the regular serration 43 is engaged with the regular serrations 41 b and 41 c of the input shaft 29, and finally the input shaft 29. In addition, it is possible to perform serration coupling by accurately positioning the joint yoke 40 in the circumferential direction.

  Further, since the serrations 50a and 50b of the slit engaging plate 48 and the serrations 41b and 41c of the input shaft 29 are serrated and coupled, the restriction force in the rotation direction of the entire slit engaging plate 48 is strong, so that the input shaft 29 and the guide member 46 are integrated. Even when transported parts are transported, the circumferential position of the guide member 46 does not shift due to vibration caused by transport, etc., and the assembly efficiency of the input shaft 29 and the joint yoke 40 can be improved. It can be performed with high accuracy.

Furthermore, for example, when the slit engaging plate 48 is rectangular, other members may collide with the corners of the distal end portion and the proximal end portion during transportation or the like. Since the slit engaging plate 48 has an inclined portion 48a on the outer periphery and a rounded portion 48b on the proximal end side, it is difficult for other members to collide with the distal end portion and the proximal end portion.
Here, as shown in FIGS. 5 and 6, the structure in which the guide member 46 is fixed to the distal end of the input shaft 29 is press-fitted into the projecting portion 28 a of the torsion bar 28 projecting from the distal end of the input shaft 29. The structure shown in FIG. 7 to FIG. 10 is conceivable in addition to the structure that fits in the state.

7, the serration 51 is formed on the outer periphery of the projecting portion 28a, the serration 52 is formed on the inner periphery of the annular connecting portion 47, and the serrations 51 and 52 are serrated and coupled to each other. A guide member 46 is fixed to the tip of the head.
Further, in the structure of FIG. 8, the torsion bar 28 is not projected at the tip of the input shaft 29, the recess 53 is provided at the tip of the input shaft 29, and the projection 55 is provided at the connecting portion 54 of the guide member 46. The guide member 46 is fixed to the tip end of the input shaft 29 by fitting the convex portion 55 into the 53 by press fitting.

9 has serrations 56 formed on the inner periphery of the recess 53 at the tip of the input shaft 29 shown in FIG. 8, and serrations 57 are formed on the outer periphery of the projections 55 of the connecting portion 54. The guide member 46 is fixed to the tip end of the input shaft 29 by serration coupling 56 and 57.
Further, in the structure of FIG. 10, a recess 53 is provided at the tip of the input shaft 29, a female screw 58 is formed on the inner surface of the recess 53, and a male screw 61 of a connection bolt 60 inserted through an annular connection portion 59 is inserted into the recess 53. The guide member 46 is fixed to the tip of the input shaft 29 by being screwed into the female screw 58.

  By fixing the guide member 46 to the tip of the input shaft 29 with the structure shown in FIGS. 7 to 10, the tip of the slit engagement plate 48 is placed on the outer periphery of the coupling portions 47, 54, 59 whose rotation is restricted. Therefore, the joint yoke 40 is positioned with respect to the input shaft 29 in the circumferential direction with high accuracy.

  In the guide member 46 shown in FIGS. 5 to 10, the slit engaging plate 48 has a shape in which an inclined portion 48a is provided on the outer periphery on the distal end side and a round portion 48b is provided on the proximal end side. It may have a shape in which a rounded portion is provided on the outer periphery of the base and an inclined portion is provided on the outer periphery on the base end side, and further, a round portion is provided on the outer periphery of both the front end side and the base end side, or The shape which provided the inclination part in the outer periphery of both of the base end side may be sufficient.

  Moreover, although the said embodiment demonstrated the coupling | bonding with the input shaft 29 of the steering gear 17 and the joint yoke 40 of the universal joint 16, the summary of this invention is not limited to this, For example, the intermediate shaft 15 And may be applied to the joint of the universal joint 14 with the joint yoke.

1 is an overall configuration diagram showing a steering device according to the present invention. It is principal part sectional drawing of the steering gear which concerns on this invention. It is a figure which shows the connection structure of the input shaft of a steering gear, and a joint yoke. It is an AA arrow directional view of FIG. It is a figure which shows the decomposition | disassembly state of an input shaft and a joint yoke. It is a figure which shows the guide member couple | bonded with the input shaft of 1st Embodiment. It is a figure which shows the guide member couple | bonded with the input shaft of 2nd Embodiment. It is a figure which shows the guide member couple | bonded with the input shaft of 3rd Embodiment. It is a figure which shows the guide member couple | bonded with the input shaft of 4th Embodiment. It is a figure which shows the guide member couple | bonded with the input shaft of 5th Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Steering device, 11 ... Steering shaft, 12 ... Steering column, 14 ... Universal joint, 15 ... Intermediate shaft, 16 ... Universal joint, 17 ... Steering gear, 18 ... Tie rod, 21 ... Steering gear case, 23 ... Rack & pinion mechanism 24 ... Electric assist mechanism, 25 ... Pinion shaft, 26 ... Rack, 27 ... Rack shaft, 28 ... Torsion bar, 29 ... Input shaft (shaft), 29a ... Shaft hole, 31 ... Electric motor, 32 ... Shaft, 33 ... Worm, 34 ... Worm wheel, 35 ... Torque sensor, 36, 37 ... Bearing, 40 ... Joint yoke, 42 ... Tightening slit (axial slit), 41a ... Ring groove, 41b, 41c ... Serration, 43 ... Serration 45 ... through hole, 46 ... guide member, 47 ... coupling part, 48 ... slit engaging plate, 48a ... inclined part, 48b ... rounded part, 49 ... through hole, 50a, 50b, 51, 52 ... serration, 53 ... concave part, 54 ... Connecting part, 55 ... Convex part, 56,57 ... Serration, 58 ... Female thread, 59 ... Connecting part, 60 ... Connecting bolt, 61 ... Male thread

Claims (8)

A slit engaging plate that engages a shaft having serrations on the outer periphery of the tip and a notched cylindrical shape having axial slits for positioning, and a joint yoke having serrations on the inner periphery. In the joint yoke and shaft coupling structure in the steering device that performs serration coupling while performing circumferential positioning by the provided guide member,
The guide member includes a connecting portion that is connected to a distal end portion of the shaft so that rotation is restricted, and the slit engaging plate is formed to protrude from an outer periphery of the connecting portion and extends along the outer periphery of the shaft. A joint yoke and shaft coupling structure in a steering device, wherein the joint yoke and shaft extend in the axial direction toward the base end side.   2. The joint yoke / shaft coupling structure in a steering apparatus according to claim 1, wherein the connecting portion is an annular member, and is fitted into a small-diameter protruding portion protruding from the tip of the shaft in a press-fitted state. .   The connecting portion is an annular member having an inner surface formed with serrations, and the serration is formed on the outer periphery of a small-diameter protruding portion protruding from the tip of the shaft, and the serration of the connecting portion and the serration of the protruding portion are serrated. The joint yoke and shaft coupling structure in the steering apparatus according to claim 1, wherein the joint yoke and the shaft are coupled.   The joint yoke according to claim 1, wherein the connecting portion is a member provided with a convex portion, and the convex portion is fitted into a concave portion provided at the tip of the shaft in a press-fitted state. Shaft coupling structure.   The connecting portion is a member having a convex portion with serrations on the outer periphery, and forms serrations on the inner surface of the concave portion provided at the tip of the shaft, and serrations the serrations of the convex portion and the serrations of the concave portion. The joint yoke / shaft coupling structure in the steering apparatus according to claim 1, wherein   The connecting portion is an annular member, and a female screw is formed on the inner surface of a concave portion provided at the tip of the shaft, and a male screw of a connecting bolt inserted through the connecting portion is screwed into and connected to the female screw of the concave portion. The joint yoke / shaft coupling structure in the steering apparatus according to claim 1.   The serration which carries out serration coupling with the serration formed in the said shaft was formed in the surface extended along the outer periphery of the said shaft of the said slit engagement board, The any one of Claim 1 thru | or 6 characterized by the above-mentioned. The joint yoke and shaft coupling structure in the described steering apparatus.   The steering apparatus according to any one of claims 1 to 7, wherein the slit engagement plate has a front end side and a base end side provided with an inclined portion or a rounded portion so that there is no corner portion. The joint yoke and shaft coupling structure in FIG.

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