KR100518189B1 - A machine for machining slots - Google Patents

Abstract

The present invention relates to an integral sleeve for a rotary valve consisting of a series of communicating slots formed in its bore, characterized in that at least a portion of the floor of one of the slots is convex. The figure shows a curved slot 21 (b) having a convex floor and opening at both ends in the axial direction of the bore 16 (b) surface 17 (b) in the sleeve 1 (b). The sleeve 1 (b) provided is shown. This slot can preferably be used as a return slot on the sleeve.

Description

Machines for machining slots {A MACHINE FOR MACHINING SLOTS}

The present invention relates to a method and apparatus for manufacturing a plurality of longitudinally extending slots in a bore of a component. One example of such a component is the sleeve element of a power steering rotary valve of a motor vehicle. In particular, the present invention relates to a sleeve element having various slot shapes and a method of manufacturing the same.

The prior art most closely related to the technology of the present invention is disclosed in US Pat. No. 5,328,309 (by Bishop et al.), US Pat. No. 5,292,214 (by Bishop et al.) And US Pat. No. 5,390,408 (by Bishop et al.). This prior art relates to a "slotting machine" for machining a slot in a bore of a power steering valve sleeve. The design of these machines is mounted on the cutting spindle, which forms a closed (usually) closed chamber or hydraulic port that is curved in the longitudinal section, reciprocating with respect to the axis with continuous deeper cutting and return strokes. Each of the slots is required to be scraped out of the bore of the lathe blank by means of a finger-shaped cutting tool. The sleeve is secured in the workpiece fixation collet, which is then mounted to the workpiece fixation spindle having a rotational axis which is perpendicular to the cutting spindle axis and offset about this axis. By precisely indexing the workpiece holding spindle at the completion of each slot, the required number of slots are machined precisely in the sleeve, typically four, six or eight slots required for most automotive devices. Do.

Such prior art slotting machines have always been arranged to longitudinally form each slot on the bore surface, which is the furthest away from the cutting spindle axis during cutting. Viewed in this respect and taking into account the curved path of the cutting tool at each cutting stroke, the slot inevitably brought a concave floor. This has limited the nature and shape of the slots that can be formed. Conventionally used concave slots were blocked at the ends, but in some designs the concave slots are drilled at one or both axial ends of the sleeve bore surface to provide for the return of oil from the sleeve.

The above limitations in the form of slots have given design limitations of the steering gear valve, the object of the present invention being to reduce such limitations.

1 is a cross-sectional perspective view of a slotting machine according to one embodiment of the present invention;

FIG. 2 is a front view of the tool head and cutting means of the embodiment shown in FIG. 1; FIG.

3 is a vertical partial cross-sectional view of the sleeve in a diameter plane with a blind-ended slot shown in relation to the cutting tool;

4 is a vertical partial cross-sectional view of the sleeve in a diameter plane with convex slot portions shown in relation to the cutting tool;

5 shows a front view of a second embodiment of a tool head and cutting means;

6 shows a front view of a third embodiment of a tool head and cutting means;

7A-7E illustrate five sleeves with various slot shapes.

In a first aspect, the present invention provides a workpiece holding device for securing a sleeve, at least one cutting tool mounted on a cutting spindle, said cutting spindle for reciprocating angular motion resulting in a cutting stroke of the tool with respect to the surface of the bore. Means for supporting the cutting tool, the cutting tool allowing the cutting tool to perform continuous deeper cutting of the bore of the sleeve, the axis of the cutting spindle being offset from the axis of the sleeve A machine for machining a slot disposed longitudinally inside a bore of said sleeve, perpendicular to said sleeve, when said cutting tool cuts at least one of said slots, said cutting tool being most proximate to said axis of the cutting spindle. Abut the surface of the bore at a proximal position.

Preferably the cutting operation takes place in the plane of diameter so that the position closest to the axis of the cutting spindle is in this plane of diameter.

Preferably the cutting tool is suitable for making a convex path to the surface of the bore with which it abuts.

In a second aspect, the present invention provides a workpiece holding device for securing a sleeve, at least one tool head for supporting a cutting means, a cutting spindle for reciprocating angular motion resulting in a cutting stroke of the cutting means with respect to the surface of the bore. Means for supporting, said cutting means comprising feed means for enabling continuous deeper cutting of said bore of said sleeve, said tool head being mounted on or integral with the cutting spindle, A machine for machining a slot disposed longitudinally within a bore of a sleeve, the axis of the cutting spindle being offset from the axis of the sleeve and perpendicular to the sleeve axis, wherein the cutting means is two or more independent cutting machines. It is characterized by including a tool.

Preferably in the first embodiment, at least one of the cutting tools is suitable for making a convex path with respect to the surface of the bore with which it abuts.

Preferably in the second embodiment, at least one of the cutting tools is suitable for making a concave path with respect to the surface of the bore with which it abuts.

In a third aspect, the invention is an integral sleeve for a rotary valve consisting of a series of communicating slots formed in its bore, wherein at least a portion of the floor of one of the slots is convex.

Preferably in one embodiment, the slot having a convex floor portion is a return slot extending longitudinally towards at least one axial end of the bore surface.

With reference to the accompanying drawings, the present invention will be described by way of example.

FIG. 1 shows a slotting machine which holds the sleeve 1 in the collet 2 of the workpiece holding spindle 3 which is mounted for both rotational and axial sliding movements in the machine base 4. The tool head 5 extends from the cutting spindle 7, which in this embodiment is integral with the cutting spindle 7. The cutting means comprise cutting tool holders 100, 101 mounted on the tool head 5 by incorporating arms (or finger-shaped protrusions) 6, 8, respectively. Arms 6 and 8 of tool holders 100 and 101 provide for mounting of cutting tools 9 and 11, respectively. The cutting spindle 7 vibrates angularly through an angle of approximately 45 degrees and the cutting tools 9, 11 are shown in their top positions. The cutting spindle 7 is itself journaled for rotation about the axis 10 inside the spindle carrier 12 which is itself journaled about the axis 13 in the cutting capsule 14.

During the cutting operation, only one of the cutting tools 9 and 11 is used in one operation, and the reciprocating motion of the cutting spindle 7 about the axis 10 gives the cutting tool a curved cutting stroke, while Vibration of the spindle carrier 12 gives the necessary feedback movement at the end of the cutting stroke.

A cam drive device housed inside the cutting capsule 14, which reciprocates the cutting tools 9, 11, is not described here, but is faithfully disclosed in US Pat. No. 5,292,214 (by Bishop et al.). The feeding mechanism may be of the kinematic cam drive type as mentioned in the prior art cited above or may be of any suitable numerically controlled servo drive mechanism suitable for giving a relatively linear horizontal motion between the cutting capsule 14 and the sleeve. It provides a means for feeding in one of the cutting tools during a cutting operation.

The workpiece holding spindle is also suitable for axial (vertical) linear motion, which is operationally similar to that disclosed in the above-mentioned prior art US Pat. No. 5,328,309 (by Bishop et al.) Or optionally by suitable numerically controlled servo drive means. . This allows to axially remove the cutting tool from the sleeve. However, in another embodiment, not shown, the relative vertical linear motion between the workpiece holding spindle and the cutting tool can be achieved by providing a vertically movable cutting capsule.

FIG. 2 is a front view independently showing the cutting tools 9 and 11 separately mounted to the arms 6 and 8 of the tool head 5 and the cutting tool holders 100 and 101, respectively. In this embodiment, the cutting tool holders 100 and 101 are each independent of each other so that they can be detachably attached to the tool head 5 while the cutting tool holders 100 and 101 can be formed as a single component. It is easy to see that.

3 shows a cutting tool 9 mounted on the arm 6 of the tool holder 100 when cutting a concave curved slot 15 with a well-known end in the bore 16. The sleeve 1 is shown in this connection. The reciprocating angular motion of the cutting tool 9 is in the radial plane of the bore 16 (ie in cross section) and abuts the surface of the bore 16 in the radial plane farthest from the cutting spindle axis 10. . In this arrangement, the cutting tip 18 of the cutting tool 9 projects outward from the tool head 5.

Since the cutting capsule 14 is linearly (horizontally) movable with respect to the tool head 5 and the workpiece holding spindle can be moved axially (vertically), the cutting tool 11 The sleeve 1 can again be positioned so that it can be used to cut a portion in another portion of the bore 16 surface 17.

4 shows the sleeve 1 in relation to a cutting tool 11 mounted on the arm 8 of the cutting tool holder 101. The reciprocating angular movement of the cutting tool 11 also takes place in the radial plane of the bore 16 and abuts the surface 19 of the bore 16 in the radial plane closest to the cutting spindle axis 10. The cutting tip 20 of the cutting tool 11 projects inward toward the tool head 5. This arrangement allows the slot floor or a portion of the slot floor to be cut somewhat convex as in 102 rather than concave. The use of slot floors with convex portions will be described later and shown in FIGS. 7B-7E.

Meanwhile, the first embodiment of the tool head shown in FIG. 2 uses finger-shaped cutting tool holders 100 and 101 capable of cutting the concave slot portion and the convex slot portion, respectively, as shown in FIG. In the second embodiment it is possible to have two finger-shaped cutting tool holders 103 and 104 for cutting slots, both of which have concave floor portions. Such an embodiment may be used to machine two different width slots on a sleeve in a single machine as shown in FIG. 1 by using different width cutting tips on cutting tools 109 and 111. .

In the third embodiment as shown in Fig. 6, two finger-shaped cutting tool holders 105 and 106 are both arranged for cutting slots having convex floor portions. Likewise, this embodiment may be used to machine two different width slots on the sleeve in a single machine as shown in FIG. 1 by using different width cutting tips on the cutting tool 107,108. Can be.

According to FIGS. 7A-7E, five different embodiments of slots 21 (a) to 21 (e) are shown in sleeves 1 (a) to 1 (e), respectively. For clarity, the outer form of the sleeve has been omitted and the size appropriately changed. Also for ease of reference, only one slot is shown in each sleeve. All five slot embodiments can be machined on the machine of the first embodiment of the present invention.

Figure 7a shows a sleeve 1 (a) having a curved slot 21 (a) with a closed end with a concave floor. This slot is similar to the slot 15 shown in FIG. 3 and may preferably be used as an inlet slot on the sleeve. Slot 21 (a) is cut in the conventional manner described above according to the tool arrangement shown in FIG. 3, wherein the reciprocating angular motion of cutting tool 9 takes place in the plane of the diameter of bore 16 (a). And abut the surface 17 (a) of the bore 16 (a) in the radial plane farthest away from the cutting spindle axis 10.

FIG. 7B shows an open-ended curved slot having convex floors and axially open at both axial ends of the bore 16 (b) surface 17 (b) in the sleeve 1 (b). The sleeve 1 (b) with 21 (b) is shown. This slot can preferably be used as a return slot on the sleeve. Slot 21 (b) is cut in the manner described above along the tool arrangement shown in FIG. 4, wherein the reciprocating angular motion of cutting tool 11 is made in the plane of the diameter of bore 16 (b) and is cut The surface 17 (b) of the bore 16 (b) in the diameter plane closest to the spindle axis 10 abuts.

FIG. 7C shows three distinctly curved slot portions, with slots flared at both axial ends of bore 16 (c) surface 17 (c) in sleeve 1 (c). The sleeve 1 (c) with the slot 21 (c) is shown. The central slot portion has a concave floor, while the two outer curved slot portions have convex floors. This slot can also preferably be used as a return slot on the sleeve. Slot 21 (c) can be machined by cutting the central concave portion of the slot by the tool arrangement shown in FIG. 3, while the two outer convex portions can be machined by the tool arrangement of FIG. 4. have. Since the machine of the first embodiment has a tool with double heads suitable for cutting both concave and convex portions, both convex and concave portions of the slot 21 (c) can be cut on the same machine. have.

FIG. 7D shows a sleeve 1 (with a slot 21 (d) ended at both axial ends of the bore 16 (d) surface 17 (d) in the sleeve 1 (d). d)). The central floor portion of the slot 21 (d) is flat, while the two outer curved slot portions have convex floors. This slot can also preferably be used as a return slot on the sleeve. These two outer curved slot portions can be cut in the manner described above according to the tool arrangement shown in FIG. 4. The flat central portion of the slot 21 (d) may optionally be convex with a large radius of curvature.

FIG. 7E shows a sleeve having a slot 21 (e) with two convex slot portions at both axial ends of the bore 16 (e) surface 17 (e) in the sleeve 1 (e). (1 (e)) is shown. These two convex slot portions can be cut in the manner described above according to the tool arrangement shown in FIG. 4.

Other slot forms not shown, utilizing the slots shown in FIGS. 7B, 7C, 7D and 7E as well as the convex slot floor portions, are also referred to herein as the "Rotary Valve for Power Steering Gear" referred to by reference. It is suitable for use as a return slot on a sleeve for use in the valves disclosed in patent application PCT / AU96 / 00266 and international patent application PCT / AU96 / 00267 entitled “Power Steering Gear Valves”.

It will be appreciated by those skilled in the art that numerous changes and modifications can be made to the invention without departing from the spirit and scope of the invention.

Claims (3)

At least one tool head mounted on the cutting spindle or integrally mounted with the cutting spindle to support the cutting means, the reciprocating angular movement resulting in the cutting stroke of the cutting means with respect to the surface of the bore; Means for supporting said cutting spindle, said feeding means enabling said cutting means to perform continuous deeper cutting with respect to said bore of said sleeve, wherein the axis of said cutting spindle is offset from the axis of said sleeve. A machine for machining a slot disposed longitudinally within a bore of a sleeve, the angle being perpendicular to the sleeve axis, wherein the cutting means comprises two finger-shaped cutting tool holders each supporting at least one cutting tool. In one of the two finger-shaped cutting tool holder The at least one cutting tool supported by the machine has a cutting tip of a width different from the width of the cutting tip on the at least one cutting tool supported by the other of the two finger-shaped cutting tool holders. 2. The machine of claim 1 wherein at least one of the two finger-shaped cutting tool holders and the cutting tool thereof are adapted to make a convex path with respect to the surface of the bore with which the cutting tool abuts. 2. The machine of claim 1 wherein at least one of the two finger-shaped cutting tool holders and the cutting tool thereof are adapted to make a concave path with respect to the surface of the bore with which the cutting tool abuts.