JP5013724B2 - Assembly method of rack and pinion type steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the cost of a rack-and-pinion type steering device by screwing an end component into a shaft end of a rack shaft without forming any exclusive engaging surface for engaging a detent tool with the rack shaft. <P>SOLUTION: The rack-and-pinion type steering device comprises a rack shaft 12 having a rack 14 engaged with a pinion to which the steering force is input, and a ball joint 16 axially screwed in a shaft end 12a of the rack shaft 12. The rack 14 has a flat surface part 40 provided for forming a gear part 14a; and the ball joint 16 is screwed to the shaft end 12a while suppressing the turn of the rack shaft 12 with a spanner 50 engaged with an end flat surface 40a of the flat surface part 40. <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

Description

  The present invention relates to an assembly of a rack-and-pinion steering device for a vehicle, which includes a rack shaft provided with a rack that meshes with a pinion to which a steering force is input, and an end part screwed into the shaft end of the rack shaft. More particularly, the present invention relates to a method of assembling end parts to the shaft end of a rack shaft.

In the rack and pinion type steering apparatus, a pair of ball joints that are end parts to which a tie rod for transmitting a steering force to a steered wheel is connected are connected to both shaft ends of the rack shaft. Usually, the ball joint is screwed into each shaft end. For this reason, a pair of engagement surfaces (hereinafter referred to as “engagement surfaces”) having a two-surface width for engaging the rotation-preventing tool so that the rack shaft does not rotate when the ball joint is screwed. Are called "face pairs"). Furthermore, an engagement surface pair with which a tool for rotating the ball joint is engaged is also formed on the ball joint (see, for example, Patent Document 1).
Japanese Utility Model Publication No. 61-16217 (FIG. 1)

  By the way, in order to form the engagement surface pair, the cost increases as much as the processing is required. From the viewpoint of reducing the manufacturing cost of the steering device, the tool is engaged to stop the rack shaft. It is desirable to eliminate the formation of the engagement surface pair only for mating. Further, with respect to the ball joint as the end part, the cost can be further reduced by eliminating the formation of the engagement surface pair for tool engagement.

  This invention is made | formed in view of such a situation, and the invention of Claims 1-3 does not form the exclusive engagement surface for engaging the tool for rotation to a rack axis | shaft. An object of the present invention is to reduce the cost of the rack and pinion type steering device by enabling the end part to be screwed into the shaft end of the rack shaft.

  According to the first aspect of the present invention, a pinion to which a steering force is input, a rack that meshes with the pinion and a rack shaft that outputs the steering force to a steering wheel, and an axial end portion of the rack shaft in an axial direction are provided. In the rack and pinion type steering apparatus provided with an end part to be screwed, the rack has a flat part provided to form the tooth part, and the rack shaft is configured by engaging a tool with the flat part. This is a method for assembling a rack-and-pinion type steering device in which the end part is screwed into the end of the shaft in a state where the rotation of the shaft is suppressed.

According to a second aspect of the present invention, there are provided a pinion to which a steering force is input, a rack in which the pinion is meshed, a rack shaft that outputs the steering force to the steered wheels, and both end portions of the rack shaft. In a rack and pinion type steering apparatus comprising first and second end parts screwed axially into the first and second shaft end parts, respectively, the first end is driven by a first tool sandwiching the first end part parts. at the same time in is pivoted state of sandwiching the parts component screwed into the first shaft end, the second tool sandwiching the second end piece, rotating in a state of sandwiching the second end piece And an assembly method of the rack and pinion type steering device, wherein the assembly is screwed into the end portion of the second shaft.

  According to a third aspect of the present invention, in the method for assembling the rack and pinion type steering apparatus according to the second aspect, the first and second end parts are sandwiched in the radial direction by the first and second tools, respectively. It rotates in the state where

  In the specification or claims, the axial direction, the radial direction, and the circumferential direction mean the axial direction of the rack shaft, the radial direction around the axis, and the circumferential direction around the axis, respectively. To do.

According to invention of Claim 1, the following effect is show | played. That is, when the end part is screwed into the shaft end of the rack shaft, the rack flat portion for forming the tooth portion is used as an engaging surface for engaging the tool for rotating the rack shaft. This eliminates the need to form a dedicated engagement surface on the rack shaft for engaging the anti-rotation tool, thereby reducing the cost of the rack-and-pinion type steering device.
According to invention of Claim 2, the following effect is show | played. In other words, by performing a rotation of the second end piece of the second tool sandwiching the rotation and a second end part of the first end piece according to the first tool sandwiching the first end part at the same time, the rack Since the shaft is stopped and the first and second end parts are screwed into the first and second shaft end parts, respectively, the first and second end parts are respectively the first and second parts of the rack shaft. When screwed into the shaft end, there is no need to engage a rotation stop tool with the rack shaft. As a result, it is not necessary to form a dedicated engagement surface on the rack shaft for engaging the rotation stop tool, so that the cost of the rack and pinion type steering device is reduced.
According to the third aspect of the present invention, in the state where the first and second tools respectively hold the first and second end parts, the both end parts are simultaneously rotated by the two tools, respectively. Since it is screwed into the end of the two shafts, it is not necessary to form a dedicated engagement surface for rotation prevention on the rack shaft, and in addition, a dedicated engagement surface for engaging the turning tool for each end part Therefore, the cost of the rack and pinion type steering device can be further reduced.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
1-3 is a figure for demonstrating 1st Embodiment of this invention.
Referring to FIGS. 1 and 2, a rack and pinion type steering device S for a vehicle to which the present invention is applied includes a steering wheel 1, an input side transmission mechanism 2 including a steering shaft, and a steering applied to the steering wheel 1 by a driver. A gear box 3 for inputting a force through the transmission mechanism 2 and outputting a steering force for steering left and right steering wheels (not shown); a tie rod 18a for transmitting the steering force from the gear box 3 to the steering wheels; And an output side transmission mechanism including 18b.

The gear box 3 includes a housing 6 attached to the vehicle body, a rack and pinion mechanism that is housed in the housing 6 and transmits a steering force to the output-side transmission mechanism, and a power steering device 20 that generates an assist steering force. .
The housing 6 includes a cylindrical rack housing 7 that extends horizontally in the left-right direction of the vehicle, and a pinion housing 8 that extends obliquely upward near one end of the rack housing 7.

  Each of the rack and pinion mechanisms is accommodated in the pinion housing 8 and rotatably supported, and the rack and pinion mechanism is accommodated in the rack housing 7 and axially (also in the left-right direction). A rack shaft 12 that is supported so as to be reciprocally movable in parallel, and a rack guide 19b that presses a rack 14 provided on the rack shaft 12 against a pinion 13 provided on the pinion shaft 11 by an elastic force of a spring 19a. A pinion shaft 11 as an output shaft is connected to an input shaft 10 through which a steering force from the handle 1 is input from the transmission mechanism 2 via a torsion bar 15. In the pinion housing 8, a tooth portion 13a formed of a large number of teeth formed on the pinion 13 and a tooth portion 14a formed of a large number of teeth formed on the rack 14 mesh with each other and rotate based on a steering force. The rack shaft 12 provided with the rack 14 driven by 13 moves in the axial direction.

The output-side transmission mechanism is a universal shaft as a pair of first and second end parts connected to first and second shaft end portions 12a and 12b which are both shaft end portions of the rack shaft 12, respectively. Ball joints 16 and 17 as joints, a pair of tie rods 18a and 18b connected to both ball joints 16 and 17, and a link mechanism (not shown) connected to each tie rod 18a and 18b With. Each of the ball joints 16 and 17 serves as a first joint portion having screw portions 16a1 and 17a1 including male screw portions that are screwed into screw portions 12a1 and 12b1 including female screw portions provided on the shaft end portions 12a and 12b. The housing portions 16a and 17a and ball portions 16b and 17b as second joint portions that are integrally formed at the ends of the tie rods 18a and 18b and are housed in the housing portions 16a and 17a are provided. The 17a is coupled to the rack shaft 12 by being screwed into the shaft end portions 12a and 12b in the axial direction.
The connecting portions between the shaft end portions 12a and 12b and the ball joints 16 and 17 are covered with a dustproof boot 9 which is coupled to the rack housing 7 at one end and coupled to the tie rods 18a and 18b at the other end.

The power steering device 20 is a hydraulic power steering device that includes a power cylinder mechanism 21 as an actuator and a supply / discharge oil system 31 that supplies / discharges hydraulic oil to / from the power cylinder mechanism 21. The power cylinder mechanism 21 includes a power cylinder 22 constituted by a part of the rack housing 7, a power piston 23 fixed to the rack shaft 12 passing through the power cylinder 22 in the power cylinder 22, and power in the power cylinder 22. It comprises a pair of left and right hydraulic chambers 24, 25 formed with a piston 23 in between.
A supply / discharge oil system 31 that supplies and discharges hydraulic oil to / from the pair of hydraulic chambers 24 and 25 includes a reservoir 32 that stores hydraulic oil, a hydraulic pump 33 that pumps hydraulic oil pumped from the reservoir 32, and a pinion housing 8 A hydraulic control valve (not shown) that is housed in the hydraulic chamber and controls supply / discharge of hydraulic oil to / from the hydraulic chambers 24 and 25 according to the relative rotation between the input shaft 10 and the pinion shaft 11, and a hydraulic pump 33 and a reservoir 32 An oil supply pipe 34 and a return oil pipe 35 for connecting the hydraulic control valve and the hydraulic control valve, respectively, and first and second control oil pipes 36 for connecting the hydraulic control valve and the hydraulic chamber 24 and the hydraulic chamber 25 of the power cylinder mechanism 21, respectively. 37.

  When the handle 1 is operated, the pinion shaft 11 rotates according to the steering direction, the rack shaft 12 moves in the axial direction, and the left and right steering wheels are steered. At this time, the hydraulic control valve is operated according to the torsion amount of the torsion bar 15 due to the rotational difference between the input shaft 10 and the pinion shaft 11 generated based on the reaction force from the road surface, that is, the steering torque, and the operation direction of the handle 1 Accordingly, hydraulic oil from the hydraulic pump 33 is supplied to the hydraulic chamber 24 (or the hydraulic chamber 25) via the oil supply pipe 34, the hydraulic control valve and the control oil pipe 36 (or the control oil pipe 37), while the hydraulic chamber 25 The hydraulic oil in the (or hydraulic chamber 24) is discharged to the reservoir 32 via the control oil pipe 37 (or control oil pipe 36), the hydraulic control valve and the return oil pipe 35, and the hydraulic pressure corresponding to the steering torque is supplied to the power cylinder mechanism 21. An assist steering force generated in each of the hydraulic chambers 24 and 25 and generated based on the differential pressure between the hydraulic chambers 24 and 25 is added to the rack shaft 12 to reduce the driver's steering force.

  Therefore, the steering device S steers the steered wheel with the steering force applied to the steering wheel 1 by the driver and the assist steering force generated by the power steering device 20 through the rack shaft 12. The steering force from the rack shaft 12 is transmitted to the steered wheels via the ball joints 16 and 17, the tie rods 18a and 18b and the link mechanism, and the steered wheels are steered.

A method of assembling the ball joints 16 and 17 to the shaft end portions 12a and 12b will be described with reference to FIGS.
The rack 14 positioned near the shaft end portion 12a in the axial direction with respect to both shaft end portions 12a and 12b is provided in part in the circumferential direction of the rack shaft 12 in parallel with the axis L (see also FIG. 2). A flat surface portion 40 (see also FIG. 2), and a tooth portion 14a composed of a large number of teeth formed on the flat surface portion 40 by cutting. As a part of the plane portion 40, there is a pair of end planes 40a and 40b which are portions closer to the shaft end portions 12a and 12b than the tooth portion 14a in the axial direction. In this embodiment, as the end plane 40a of at least one of the both end planes 40a and 40b, the end plane 40a close to the ball joint 16 in the axial direction is connected to the rack shaft 12 by the ball joints 16 and 17. , It constitutes only one engaging surface with which the spanner 50 as a turning stop tool for suppressing the rotation of the rack shaft 12 when screwed into the corresponding shaft end portions 12a, 12b is engaged.

In assembling the steering device S, the ball joints 16 and 17 are assembled to the shaft end portions 12a and 12b, respectively, in the following assembly process, for example.
In a state where the rack shaft 12 and the pinion shaft 11 (see FIG. 2) are assembled to the housing 6, the end flat surface 40a protrudes from the rack housing 7 in one axial direction (rightward in FIG. 3A). The rack shaft 12 is moved so as to occupy. In this state, the receiving portion 16a of the ball joint 16 in a state where the tie rod 18a is connected to one shaft end portion 12a of the rack shaft 12 does not use the spanner 50, and the screw portion 16a1 is connected to the screw portion of the shaft end portion 12a. It is screwed to 12a1 and screwed to near the screwing completion position (this state is shown in FIG. 3A). Next, in order to firmly tighten the accommodating portion 16a to the shaft end portion 12a at the final stage of screwing, as shown in FIGS. 3A and 3B, the spanner 50 is engaged with the end portion plane 40a. With the rack shaft 12 stopped, a turning tool (not shown) such as a spanner is engaged with the engaging portion formed in the housing portion 16a, and the housing portion 16a is rotated by the turning tool. Then, the accommodating portion 16a is screwed into the shaft end portion 12a until the screwing completion position.

Next, with respect to the other shaft end portion 12b as well, the housing portion 17a of the ball joint 17 first replaces the screw portion 17a1 with the screw portion of the shaft end portion 12b without using the spanner 50 as in the case of the shaft end portion 12a. After being screwed into 12b1 and screwed into the shaft end portion 12b to the vicinity of the screwing completion position, the spanner 50 is engaged with the end surface plane 40a and the rack shaft 12 is stopped, and the housing portion 17a is A rotating tool (not shown) is engaged with the formed engaging portion, and the accommodating portion 17a is rotated with the rotating tool to screw the accommodating portion 17a into the shaft end portion 12b to the screwing completion position.
In this way, as shown in FIG. 1, both ball joints 16 and 17 are connected to both shaft end portions 12a and 12b of the rack shaft 12, respectively.

Next, operations and effects of the embodiment configured as described above will be described.
The rack 14 provided on the rack shaft 12 of the steering device S has a flat surface portion 40 provided for forming the tooth portion 14a, and the spanner 50 is engaged with the end flat surface 40a of the flat surface portion 40 to thereby rack the rack. When the ball joints 16 and 17 are screwed into the shaft end portions 12a and 12b by screwing the ball joints 16 and 17 into the shaft end portions 12a and 12b in a state where the rotation of the shaft 12 is suppressed, the rack shaft 12 Since the flat surface portion 40 of the rack 14 for forming the tooth portion 14a is used as the engagement surface for engaging the spanner 50 for stopping rotation, the exclusive use for engaging the spanner 50 for stopping rotation is used. Since the process of forming the engaging surface on the rack shaft 12 becomes unnecessary, the cost of the steering device S is reduced.

  Next, a second embodiment of the present invention will be described with reference to FIG. In addition, description about the same part as 1st Embodiment is abbreviate | omitted or simplified, and it demonstrates focusing on a different point. Moreover, the same code | symbol was used as needed about the same member as the member of 1st Embodiment, or a corresponding member.

  In the steering device S (see FIG. 1), the housing portions 16a and 17a of the ball joints 16 and 17 are screwed into the shaft end portions 12a and 12b with the housing portions 16a and 17a having the screw portions 16a1 and 17a1, respectively. An engagement surface for engaging a tool for rotating the ball joints 16 and 17 is not formed. The pair of first and second turning tools 51 and 52 for turning the housing portions 16a and 17a respectively include, for example, a pair of gripping portions 51a and 51b; 52a and 52b. The holding portions 16a and 17a are gripped by the portions 51a and 51b; 52a and 52b while being sandwiched in the radial direction. Each of the accommodating portions 16a and 17a is not provided with a special structure for being held by the tools 51 and 52.

In assembling the steering device S, the ball joints 16 and 17 are assembled to the shaft end portions 12a and 12b, respectively, in the following assembly process, for example.
A ball joint 16 in which the tie rods 18a and 18b are coupled to the shaft end portions 12a and 12b in a state where the rack shaft 12 and the pinion shaft 11 (see FIG. 2) are assembled to the housing 6 (see FIG. 1). The 17 accommodating portions 16a and 17a are screwed into the shaft end portions 12a and 12b to the vicinity of the screwing completion position without using a tool (this state is shown in FIG. 4). Next, in order to firmly tighten the receiving portions 16a and 17a to the shaft end portions 12a and 12b at the final stage of screwing, the respective tools 51 and 52 are gripped with the corresponding receiving portions 16a and 17a being tightened in the radial direction. Then, the accommodating portions 16a and 17a are simultaneously rotated by both the tools 51 and 52, and the accommodating portions 16a and 17a are screwed into the shaft end portions 12a and 12b, respectively, to the screwing completion positions.
In this manner, as shown in FIG. 1, both ball joints 16 and 17 are connected to both ends 12a and 12b of the rack shaft 12, respectively.

  According to the second embodiment, the housing 51a of the ball joint 16 is rotated by the tool 51 and screwed into the shaft end 12a, and at the same time the ball joint 17 is rotated by the tool 52 to the shaft end 12b. By screwing, the rotation of the ball joint 16 by the tool 51 and the rotation of the ball joint 17 by the tool 52 are simultaneously performed, whereby the rotation of the rack shaft 12 is performed, and both the ball joints 16 and 17 are respectively racked. Since both the ball joints 16 and 17 are screwed into the shaft end portions 12a and 12b, respectively, it is necessary to engage a rotation stop tool with the rack shaft 12 because the ball joints 16 and 17 are screwed into the shaft end portions 12a and 12b, respectively. Absent. This eliminates the need for forming a dedicated engagement surface on the rack shaft 12 for engaging the anti-rotation tool, so that the same operations and effects as in the first embodiment are achieved.

  In addition, by rotating both the ball joints 16 and 17 while being sandwiched in the radial direction by the tools 51 and 52, respectively, the tools 51 and 52 hold the both ball joints 16 and 17, respectively. Since both the ball joints 16 and 17 are simultaneously rotated by 51 and 52 and screwed into the shaft end portions 12a and 12b, respectively, it becomes unnecessary to form a dedicated engagement surface for the rotation prevention in the rack shaft 12. As a result, the ball joints 16 and 17 do not require a process for forming a dedicated engagement surface with which the turning tool is engaged, so that the cost of the steering device S is further reduced.

Hereinafter, an embodiment in which a part of the configuration of the above-described embodiment is changed will be described with respect to the changed configuration.
In the first embodiment, the ball joints 16 and 17 are rotated by tightening the receiving portions 16a and 17a with a turning tool without forming an engaging surface for engaging the turning tools with the receiving portions 16a and 17a. Then, it may be screwed into the shaft end portions 12a and 12b. As a result, it is not necessary to form a dedicated engagement surface for engaging the rotating tool with the ball joints 16 and 17, so that the cost is further reduced as in the second embodiment.
In the second embodiment, a single engaging surface or a pair of engaging surfaces is formed in the receiving portions 16a and 17a, and the holding portions 16a and 17a are held on the engaging surfaces without being gripped by a turning tool. The ball joints 16 and 17 may be simultaneously rotated by engaging a rotating tool and screwed into the shaft end portions 12a and 12b. Also in this case, the rack shaft 12 does not need to be formed with a dedicated engagement surface for engaging the anti-rotation tool, so that the same effect as that of the first embodiment can be obtained.

1 is a front view of a main part of a rack and pinion type steering apparatus to which the present invention is applied, showing a first embodiment of the present invention. It is principal part sectional drawing in the II-II line | wire of FIG. FIG. 2 is a diagram for explaining a process of assembling a ball joint to a rack shaft in the steering device of FIG. 1, and (A) is a diagram showing a partial cross-section of a main part centering on the shaft end of the rack shaft of FIG. 1. (B) is a figure when the tool for rotation prevention is engaged in the BB line sectional view of (A). FIG. 6 is a diagram showing a second embodiment of the present invention and a partial cross section showing a main part centering on both shaft ends of a rack shaft of a rack and pinion type steering apparatus to which the present invention is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Handle, 2, 4 ... Transmission mechanism, 3 ... Gear box, 6 ... Housing, 7 ... Rack housing, 8 ... Pinion housing, 9 ... Dust-proof boot, 10 ... Input shaft, 11 ... Pinion shaft, 12 ... Rack shaft 12a, 12b ... shaft end, 13 ... pinion, 14 ... rack, 15 ... torsion bar, 16, 17 ... ball joint, 18a, 18b ... tie rod, 20 ... power steering device, 21 ... power cylinder mechanism, 22 ... power Cylinder, 23 ... Power piston, 24,25 ... Hydraulic chamber, 31 ... Supply / drain oil system, 32 ... Reservoir, 33 ... Hydraulic pump, 34 ... Oil supply pipe, 35 ... Return oil pipe, 36,37 ... Control oil pipe, 40 ... Plane Part, 50 ... spanner, 51, 52 ... turning tool,
S: Steering device.

Claims (3)

A pinion to which a steering force is input, a rack that meshes with the pinion is provided, a rack shaft that outputs the steering force to a steered wheel, and an end part that is screwed in an axial direction to the shaft end of the rack shaft. In the rack and pinion type steering device,
The rack has a flat portion provided to form the tooth portion, and the end part is moved to the shaft in a state where a rotation of the rack shaft is suppressed by engaging a tool with the flat portion. A method of assembling a rack-and-pinion type steering apparatus, characterized by being screwed into an end portion. A pinion to which a steering force is input, a rack that meshes with the pinion and a rack shaft that outputs the steering force to a steering wheel, and first and second shaft end portions that are both shaft end portions of the rack shaft are provided. In a rack and pinion type steering apparatus comprising first and second end parts screwed in the axial direction,
The first tool that sandwiches the first end part is rotated with the first end part sandwiched and screwed into the first shaft end, and at the same time, the second tool sandwiches the second end part . A method of assembling a rack and pinion type steering apparatus, wherein the second end part is rotated with a tool and is screwed into the second shaft end part.   The rack-and-pinion type steering device assembly according to claim 2, wherein the first and second end parts are rotated while being sandwiched in the radial direction by the first and second tools, respectively. Method.

Images