JPH1085884A - Rack shaft material clamping device for rack shaft manufacturing equipment - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To enable rack teeth to be formed on a rack shaft material with high precision. SOLUTION: A rack shaft material 11 is pressed and held on each clamp surface 56A, 56B of a pair of clamp members 46A, 46B, and rack teeth are rolled on the outer peripheral surface of the rack shaft material by sliding of a rolling roll 30. In the rack-shaft material clamping device 25 of the rack-shaft manufacturing device that can be machined, each of the clamping surfaces of the pair of clamp members is formed to have substantially the same curvature as the outer peripheral surface of the rack-shaft material, and the racks are located at opposing positions. It has a projection 57 that can be cut into the outer peripheral surface of the shaft material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rack shaft manufacturing apparatus applied to a rack shaft manufacturing apparatus for rolling a rack tooth by sliding a rolling roll on an outer peripheral surface of a hollow pipe-shaped rack shaft material. The present invention relates to a rack shaft material clamping device.

[0002]

2. Description of the Related Art In general, a rack shaft used in a steering mechanism of an automobile is formed by flattening a part around a round bar and forming rack teeth there. At this time,
The use of a hollow pipe as the rack shaft material has been implemented because of a demand for weight reduction.

[0003] As a rack shaft manufacturing apparatus for forming rack teeth by plastic working on the rack shaft material, the present applicant has disclosed in Japanese Patent Application No. 6-337053 a pair of clamp members capable of contacting and separating the rack shaft material. And presses and holds, and slides a rolling roll on the outer peripheral surface of the rack shaft material to roll the rack teeth.

[0004]

However, in the above-mentioned prior application technique by the present applicant, during the rolling of the rack teeth, the tangential direction on the outer peripheral surface of the rack shaft material is changed from the rolling roll to the rack shaft material. There is a risk that the working force of the above will act and the circumferential rack shaft material will rotate around the shaft with respect to the clamp member, which may hinder the accuracy of the rack teeth.

An object of the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a rack shaft material clamping device of a rack shaft manufacturing device capable of forming rack teeth on a rack shaft material with high accuracy. .

[0006]

According to a first aspect of the present invention, a rack shaft material is pressed and held on each of the clamp surfaces of a pair of detachable clamp members, and the rack is slid by rolling rollers. In the rack shaft material clamping device of the rack shaft manufacturing device that can form the rack teeth on the outer peripheral surface of the shaft material, the clamp surfaces of the pair of clamp members are:
The rack shaft material is formed to have substantially the same curvature as the outer peripheral surface, and has a projection at a position substantially opposed to the outer peripheral surface of the rack shaft material.

According to a second aspect of the present invention, in the first aspect of the invention, a plurality of projections formed on the clamp surface of the clamp member are provided along a longitudinal direction of the rack shaft material. is there.

The first aspect of the present invention has the following operation. When the rack shaft material is pressed and held by the clamp member on each of the clamping surfaces of the pair of clamp members, a projection that cuts into the outer peripheral surface of the rack shaft material is formed. Even when a tangential processing force is applied to the outer peripheral surface of the rack shaft material from the rack shaft material, the rack shaft material can be prevented from rotating around the shaft with respect to the clamp member. As a result, rack teeth can be formed on the outer peripheral surface of the rack shaft material with high accuracy.

The invention according to claim 2 has the following operation. Since a plurality of protrusions are provided on the clamp surface of the clamp member along the longitudinal direction of the rack shaft material, the rotation of the rack shaft material during rolling of the rack teeth can be reliably prevented, and the rack shaft material is formed. Rack teeth can be formed with higher precision.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a front view showing a rack shaft manufacturing apparatus to which one embodiment of a rack shaft material clamping device of the rack shaft manufacturing apparatus according to the present invention is applied.
FIG. 2 is an enlarged sectional view showing a part of FIG. FIG.
(A) is a view on arrow IIIA in FIG. 2, and FIG.
FIG. 3 is an arrow view along the line IIIB-IIIB in FIG. FIG.
FIG. 4 is a sectional view taken along line IV-IV in FIG. FIG.
FIG. 3 is a perspective view showing a rack shaft.

As shown in FIG. 5, the rack shaft 10 is provided on a part of the outer peripheral surface of a rack shaft material 11 made of a hollow round pipe.
It has a large number of rack teeth 12 intersecting in the axial direction.

The rack shaft manufacturing apparatus 20 includes a base 21
, A fixed frame 22, a machine frame 23, a movable frame 24, a material clamping device 25, a mandrel setting device (not shown), a rolling roll moving device (not shown), and a material moving device 28. Forming roll 3 having a rack tooth profile formed on its peripheral surface
0, the rack shaft material 1 and the roll 30 are relatively slid in the tangential direction of the roll 30 with the core metal 13 (FIG. 2) inserted into the rack material 11. The rack teeth 12 are rolled on the rack shaft material 11.

Hereinafter, components of the rack shaft manufacturing apparatus 20 will be described. (A) Base Base 21 and the like As shown in FIG. 1, a fixed base 22 and a machine frame 23 are erected on the base base 21 by bolts. Machine frame 23
Has a side plate 23A and a top plate 23B. Fixed stand 2
2 and the side plate 23 </ b> A of the machine casing 23 are connected by a total of four screw shafts 31. That is, the screw shaft 31 has one end rotatably and axially integrated with the fixed gantry 22 and the other end freely rotatable and axially integrated with the side plate 23A of the machine frame 23. And side plate 23A of machine frame 23
And the frame are integrated.

As shown in FIG. 1, the movable gantry 24 is connected between the fixed gantry 22 and the side plate 23A of the machine frame 23 by the above-described four steps.
The screw shaft 31 is screwed into each screw portion 31A of the screw shaft 31.
It can be moved by the rotation of. At this time, the movable base 2
Reference numeral 4 denotes a slide 24A provided on the lower surface
1 and a slide (not shown) provided on the upper surface thereof is fitted to a guide rail 33 below a top plate 23B of the machine frame 23. A gear 34 is fixed to a portion of one end of each screw shaft 31 protruding from the fixed base 22. On the other hand, a motor 35 is provided on the base 21, and a gear 36 driven by the motor 35 meshes with a gear 34 of each screw shaft 31 via an intermediate gear (not shown). That is, the movable gantry 24 is guided by the guide rails 32 and 33 and moves by the rotation of the screw shaft 31 by the motor 35, so that the distance between the movable gantry 24 and the fixed gantry 22 can be adjusted.

(B) Material Clamping Device 25 (Part 1) As shown in FIG. 1, the material clamping device 25 is provided on both sides in the radial direction of the roll 30 in a point symmetry passing through the roll axis of the roll 30. Left and right clamp housings 4
1, 42. Both clamp housings 41, 42
Are slidably disposed on opposite side surfaces of the fixed gantry 22 and the movable gantry 24 via material reciprocating cylinders 81 and 82 laid on the fixed gantry 22 and the movable gantry 24, respectively.

Each of the clamp housings 41 and 42 has a recess 45 as shown in FIG. This recess 4
5, clamp members 46A and 46B divided into upper and lower parts
And the rack shaft material 11 is held between the clamp members 46A and 46B. Within the recess 45, the upper and lower clamp members 46A and 46B are arranged so as to be movable in the vertical direction, and a spring 4 for expanding is provided between the clamp members 46A and 46B.
7, a pair of clamp cams 48A, 48B are provided outside the clamp members 46A, 46B. The clamp housings 41 and 42 are connected to the plungers 49 screwed and integrated with the clamp cams 48A and 48B.
A, 49B are provided with hydraulic working chambers 51A, 51B. The hydraulic working chambers 51A and 51B are respectively formed by forming a first chamber 52 and a second chamber 53 on both sides of the plungers 49A and 49B, and the first chamber 52 and the second chamber 53 communicate with oil passages 54 and 55, respectively. Is done.

In each of the right and left clamp housings 41 and 42, the first chamber 5 of the hydraulic working chambers 51A and 51B is provided.
2 is supplied with hydraulic oil and the clamp cams 48A, 48B move rightward (FIG. 2), the clamp members 46A,
6B closes and holds the rack shaft blank 11. Thereby, the left and right rack shaft materials 11, 11 held on the left and right clamp housings 41, 42 face each other on the point symmetry on both sides in the radial direction passing through the roll axis of the roll 30. It is held and the rolling process thereof can be started. When the rolling of the rack shaft blanks 11 is completed,
In each of the left and right clamp housings 41 and 42, hydraulic oil is supplied to the second chamber 53 of the hydraulic operating chambers 51A and 51B, and the clamping cams 48A and 48B move to the left (FIG. 2). 46B is expanded by the spring force of the spring 47 to release the holding of the rack shaft material 11.

(C) Core setting device The core setting device comprises left and right clamp housings 41, 42.
A core metal cylinder (not shown) is provided on each rear surface, whereby the metal core 13 is set at a material insertion position between the clamp members 46A and 46B, and the metal core 13 is inserted into the pipe of the rack shaft material 11. Then, the rolling process of the rack shaft material 11 can be started.

(D) Roll forming roll moving device The rolling roll moving device includes a clamp housing 41 on the fixed gantry 22 side and a clamp housing 4 on the movable gantry 24 side.
2 on a rolling roll moving table (not shown)
Both ends of the roll shaft of the roll 30 are rotatably supported via bearings.

The rolling roll moving table is mounted on the base 21 and is movable along a guide rail (not shown) laid in parallel with the guide rail 32, and is guided by the rotation of the motor 35 to the guide rail. The fixed base 22 is moved.

Each time the clamp housings 41 and 42, which will be described later, slide, the motor 35 moves the above-described rolling roll 30 and the above-mentioned movable gantry 24 in a direction approaching the fixed gantry 22, and is processed into the rack shaft material 11. The depth of the rack teeth 12 is gradually increased. At this time, the moving amount of the movable gantry 24 and the moving amount of the rolling roller 30 are set to be two to one, and the clamp housing 41 on the fixed gantry 22 side and the clamp housing 42 on the movable gantry 24 side are respectively provided. The rack tooth depth of the held rack shaft material 11 is the same.

(E) Material moving device 28 The material moving device 28 shown in FIG. 1 includes left and right material reciprocating cylinders 81, 8 on a fixed frame 22 and a movable frame 24, respectively.
2, the left clamp housing 41 is connected to the rod of the left material reciprocating cylinder 81 via the left connecting bracket 83, and the right clamp housing 42 is connected to the rod of the right material reciprocating cylinder 82 via the right connecting bracket 84. Connected and consequently their clamp housings 41, 42
Is moved in the tangential direction of the rolling roll 30.

At this time, the left and right clamp housings 4
A swing lever 87 having a swing center set at an intermediate position (the same position as the rolling roll 30) between the left and right clamp housings 41 and 42 is provided so that the swing levers 1 and 42 are synchronized with each other and moved in opposite directions. , Plungers 85, 86 slidable in the horizontal direction via bearings in fitting holes 83A, 84A provided in the left and right connection brackets 83, 84, respectively.
And the both lever ends of the swinging lever 87 are pivotally connected to their plungers 85 and 86.

On the top plate 23B of the machine frame 23, a guide rail (not shown) is provided in parallel with the guide rail 32. The guide rail is provided with a movable pivot 87A (swing center). A bearing (not shown) is guided. The movable bearing is guided and moved by the guide rail by the rotation of the motor 35, and is adjusted so that the swing support shaft 87A of the swing lever 87 is always positioned at the same position as the rolling roll 30.

As a result, the material moving device 28 is moved downward (or upward) by the left material reciprocating cylinder 81 and upward (or downward) by the right material reciprocating cylinder 82 to the right connecting bracket 84. ), The left and right rack shaft blanks 11, 11 held in the left and right clamp housings 41, 42 move in opposite directions while pressing against both radial surfaces of the roll 30. Each rack shaft material 11 relatively slides in the tangential direction of the rolling roll 30. At this time, the roll 30 rotates counterclockwise (or clockwise).
Note that the sliding directions of the left and right rack shaft materials 11, 11 are opposite to each other as described above (if the left connecting bracket 83 moves up, the right connecting bracket 84 moves down, and the rolling roll 30 rotates Direction).

In the rack shaft manufacturing apparatus 20, the movement cycle of the material reciprocating cylinders 81 and 82 is
In each of the reciprocating movements of the left and right rack shaft materials 11, 11 by the material moving device 28, the movable gantry 24, the rolling roll 30, and the movable bearing (the swing support shaft 87A of the swing lever 87). ) Is brought closer to the fixed base 22 by a fixed amount. The movement of the movable gantry 24 and the rolling roll 30 is synchronized with the vertical movement of the left and right clamp housings 41 and 42 with respect to the rolling roll 30, and for each sliding stroke of the left and right rack shaft materials 11 with respect to the rolling roll 30, The center distance between the left and right rack shaft blanks 11 and the rolls 30 is reduced by the same amount on the left and right as described above.
The tooth depth of the rack teeth 12 to be processed into 1 is gradually increased.

(F) Material Clamping Device 25 (Part 2) As described above, the clamping members 46A and 46B in the material clamping device 25 shown in FIG.
8A and 48B and the spring 47 for expanding, the rack shaft material 1
1 is pressed and held in contact with the respective clamp surfaces 56A, 56B of these clamp members 46A, 46B. These clamping surfaces 56A, 56B are shown in FIG.
As shown in FIG. 3B, the clamp members 46A,
6B are formed over the entire length of the opposing surfaces inclined at a predetermined angle with respect to the longitudinal direction, and have substantially the same curvature as the outer peripheral surface of the rack shaft blank 11. Thereby, the clamp surfaces 56A and 56B press the substantially right half area in FIG. 2 of the outer peripheral surface of the rack shaft blank 11.

Further, these clamping surfaces 56A and 56A
As shown in FIGS. 3B and 4, a projection 57 is integrally formed on B at a position facing the same. The plurality of protrusions 57 are formed on each of the clamp surfaces 56A, 56B along the longitudinal direction of the rack shaft material 11 pressed and held by these clamp surfaces 56A, 56B. These projections 57 are provided so as to be able to bite into the outer peripheral surface of the rack shaft blank 11 pressed and held by the clamp surfaces 56A and 56B, and are formed during rolling of the rack teeth 12 by the rolling rolls 30. Even if the processing force F acts on the rack shaft blank 11 from the forming roll 30 in the tangential direction of the outer peripheral surface of the rack shaft blank 11, the rack shaft blank 11 is clamped by the clamping members 46A and 46B.
, So that it cannot rotate around its axis.

Hereinafter, a procedure for manufacturing the rack shaft 10 by the rack shaft manufacturing apparatus 20 will be described. (1) The core metal 13 is fixed to the clamp members 46A, 4A of the left and right clamp housings 41, 42 by the core metal setting device.
It is set to the material insertion position between 6B.

(2) The left and right rack shaft materials 11, 11 are positioned at the material insertion positions between the clamp members 46A, 46B of the left and right clamp housings 41, 42, respectively.
(1) Insert the metal core 13 into the rack shaft blank 11. At this time, the end face of the rack shaft material 11 is
The rack shaft material 11 is positioned in the longitudinal direction by abutting the material stoppers provided on the first and second materials 42.

(3) The left and right rack shaft blanks 11, 11 are separated by the blank clamp housing 4 by the blank clamp device 25.
1 and 42 are clamped and held between the respective clamp members 46A and 46B. At this time, the left and right rack shaft materials 11, 1
1 is pressed and held in contact with the respective clamp surfaces 56A, 56B of the clamp members 46A, 46B, and is disposed opposite to the point symmetry on both sides in the radial direction passing through the roll axis of the roll 30.

(4) The movable platform 24 and the rolling roll 30 are set to appropriate forward positions with respect to the fixed platform 22 by the motor 35, and then the left and right clamp housings 41 and 42 are moved up and down by the material moving device 28. . As a result, the left and right rack shaft materials 11, 11 clamped and held on the right and left clamp housings 41, 42 bite into the outer peripheral portion of the rolling roll 30 while being supported on the back surface by the metal core 13, and slide. The shallow rack teeth 12 are rolled by cold working. At this time, the left and right rack shaft materials 1
The rollers 1 and 11 slide on the outer periphery of the roll 30 in opposite directions while maintaining a point symmetrical positional relationship passing through the roll axis of the roll 30.

(5) Thereafter, the movable stand 24 and the rolling roll 30 are moved closer to the fixed stand 22 by the motor 35 at each sliding stroke of the left and right rack shaft materials 11 and 11 with respect to the rolling roll 30 in the above (4). The rack shaft blanks 11, 11 and the rolling roll 30 are narrowed by moving the rack shaft blanks 11, 11 by a predetermined amount in the direction, and the depth of the rack teeth 12 is gradually increased. Form teeth 12.

According to the above embodiment, the following effects can be obtained. Each clamp surface 5 of the pair of clamp members 46A, 46B
6A and 56B, when the rack shaft material 11 is pressed and held by the clamp members 46A and 46B, the rack shaft material 11
Is formed on the outer peripheral surface of the rack shaft material 11, the tangential processing force on the outer peripheral surface of the rack shaft material 11 is applied to the rack shaft blank 11 from the roll 30 during the rolling of the rack teeth 12. Even if F acts, the rack shaft material 1
1 can be prevented from rotating about its axis with respect to the clamp members 46A, 46B. As a result, the rack shaft material 1
The rack teeth 12 can be formed with high precision on the outer peripheral surface of the rack 1.

Since a plurality of projections 57 are provided on each of the clamp surfaces 56A, 56B of the clamp members 46A, 46B along the longitudinal direction of the rack shaft blank 11, the rack shafts during the rolling of the rack teeth 12 are formed. The rotation of the material 11 can be reliably prevented, and the rack teeth 12 can be formed on the rack shaft material 11 with higher accuracy.

In the above embodiment, the clamping surface 56 of the clamping member 46A in the material clamping device 25 is used.
A, the clamp surface 56B of the clamp member 46B is provided to be inclined with respect to the longitudinal direction of each of the clamp members 46A, 46B to form the rack teeth 12 of helical teeth on the rack shaft material 11, Clamp member 46
The clamp surface 56A of A and the clamp surface 56B of the clamp member 46B may be provided in parallel with the longitudinal direction of each of the clamp members 46A and 46B to form the rack teeth 12 of straight teeth on the rack shaft material 11.

[0037]

As described above, according to the rack shaft blank clamping device of the rack shaft manufacturing apparatus according to the present invention, rack teeth can be formed on the rack shaft blank with high accuracy.

[Brief description of the drawings]

FIG. 1 is a front view showing a rack shaft manufacturing apparatus to which one embodiment of a rack shaft material clamping device of a rack shaft manufacturing apparatus according to the present invention is applied.

FIG. 2 is an enlarged sectional view showing a part of FIG. 1;

3 (A) is a view taken along the line IIIA in FIG. 2, and FIG. 3 (B) is a view taken along the line IIIB-IIIB in FIG. 3 (A).

FIG. 4 is a sectional view taken along line IV-IV in FIG. 3 (B).

FIG. 5 is a perspective view showing a rack shaft.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Rack shaft 11 Rack shaft material 12 Rack teeth 25 Material clamping device 30 Rolling roll 46A, 46B Clamp member 56A, 56B Clamp surface 57 Projection

Claims (2)

[Claims] 1. A rack shaft material is pressed and held on each clamp surface of a pair of detachable clamp members, and rack teeth can be roll-formed on the outer peripheral surface of the rack shaft material by sliding of a rolling roll. In the rack shaft material clamping device of the rack shaft manufacturing apparatus, the clamp surfaces of the pair of clamp members are formed to have substantially the same curvature as the outer peripheral surface of the rack shaft material, and at positions substantially opposed to each other, A rack shaft material clamping device for a rack shaft manufacturing device, characterized in that the rack shaft material has a protrusion that can be cut into the outer peripheral surface of the rack shaft material. 2. The rack shaft material clamping device according to claim 1, wherein a plurality of protrusions formed on the clamp surface of the clamp member are provided along a longitudinal direction of the rack shaft material.