WO2002103214A1

WO2002103214A1 - Linear guide for translating slides mounted on rolling members

Info

Publication number: WO2002103214A1
Application number: PCT/IB2002/000819
Authority: WO
Inventors: Alessandro Cariani
Original assignee: Alessandro Cariani
Priority date: 2001-06-20
Filing date: 2002-03-20
Publication date: 2002-12-27
Also published as: ITMI20011294A0; EP1402192A1; ITMI20011294A1

Abstract

Linear guide for the translation of slides on rolling members, of the type comprising one or more concave supporting elements, in which the supporting element or each supporting element defines at least one sliding race for the slides. The supporting element or each supporting element comprises means for coupling to another of the aforesaid supporting elements to extend the sliding race.

Description

"Linear guide for translating slides mounted on rolling members." TECHNICAL FIELD

The present invention relates to a linear guide for the translation of slides mounted on rolling members (rolling parts), such as rollers or balls, of the type comprising at least one rectilinear supporting element, usually concave, which defines one or more axial sliding races for the slides. PRIOR ART In order to produce linear guides which engage with slides with rolling members, such as those used fo allow relative sliding of a mobile element in relation to a load-bearing structure, prior art employs rectilinear metal supporting elements (section bars) in the shape of a "C" which define at least one axial race (track) inside which said rolling members can be housed and rotate in order to allow the slides to translate in relation to the guide.

In particular, the metal section bar usually has a central core portion and, at its ends, two wings in various shapes which define the concavity of the section bar and the inside surfaces of which form races (tracks) on which the rollers of rolling pins or the ball bearings of the slides rest and rotate when the slide is made to translate in relation to the guide.

In other embodiments, also extremely common, the rollers or ball bearings rest on the outside of and rotate externally fo the section bar, while the slide slides internally. The core portion of the section bar is also usually perforated to allow the guide to be anchored to the load-bearing structure by means of threaded fixing means, such as screws or bolts, and the sliding races of the wings are suitably lubricated to prevent excessive friction between pins and the resting surfaces from impeding sliding of the slides in the guide.

In view of the wide field of applications in which said guides can be employed, varying for example from the mounting of sliding doors to the use in devices for the translation of parts of machine tools, the above described guides must be able to satisfy a wide variation of technical characteristics in terms of load-carrying capacity, rigidity (stiffness) or elasticity, tolerances and in particular dimensions. In relation to the load-carrying capacity and other mechanical characteristics of the guides, in addition to variation in geometric characteristics of the section of the section bar, it is common practice to employ different metal materials, such as steels or aluminium alloys, according to the requirements that the section bar must satisfy. The use of metal materials entails simple design of the section bar, but also a certain degree of difficulty in producing complex shapes and obtaining particularly restricted tolerances (allowances). With regard to the dimensions of the section bar, and in particular with regard to its length, in order to avoid ad hoc production of section bars for each single application, the production and laying of these guides usually entails the manufacture, normally by extrusion, of long metal section bars and subsequent cutting of these to adapt them to the dimensional specifications required.

Although efficient from the point of view of production, this technique requires a considerable amount of time to lay the guides and entails a certain amount of waste material caused by the scraps unavoidably obtained at the end of the cutting operation.

According to another prior technique, in order to speed up the laying procedure and minimize scraps, each type of section bar is produced in α plurality of sizes with different lengths. Therefore, by choosing the section bar with the most suitable length to the dimensional specification required, although the subsequent phase of cutting the section bar cannot be eliminated, it is possible to reduce the times required for laying and the quantity of scraps produced.

Nonetheless, this technique also has various disadvantages. In fact, it requires the storage of a large number of section bars, it does not eliminate the problem of scraps and a considerable amount of resources are required to manage the plurality of items produced. Moreover, in the case in which it is necessary to join the ends of two different section bars, for example to lay guides of an exceptional length, special instruments must be used to align the section bars in order to guarantee continuity of the sliding races for the rolling members of the slides, which entails an increase in times and costs required for laying.

An object of the present invention is to produce a linear guide for the sliding of slides on rolling members devoid of the problems of prior art as regards production and laying. Another object of the present invention is to produced a linear guide which, although having the required mechanical characteristics, is simple and economical to lay, so that scraps are minimized and there is no need to keep a large number of items in stock. A further object of the present invention is to supply a linear guide for slides on rolling members in which the rectilinear supporting element for the rolling members is easy to produce, even in the case of complex shapes. SUMMARY OF THE INVENTION These and other objects are attained by the linear guide for the translation of slides on rolling members as claimed in the first independent claim and in the subsequent dependent claims. The linear guide for the translation of slides on rolling members according to the present invention comprises one or more concave rectilinear supporting elements, each of which defines at least one axial sliding race for the slides. Moreover, each supporting element is provided with means for coupling to another supporting element to extend the axial sliding race. According to a preferred aspect of the present invention, these coupling means to extend the sliding race comprise, at one end section of the supporting element, one or more axial seats and at the other end section of the supporting element pins engagable in said seats. According to another aspect of the present invention, the supporting elements are produced, by thermoforming or injection moulding, employing at least one thermoplastic material, such as polyamides, polycarbonates, ABS or thermoplastic polyurethanes, which may be reinforced by an internal sheet in metal or in a composite material. In preferred embodiments, moreover, the profile of the supporting elements comprises a central core part and two V-shaped wings, provided at the ends of the core part, in which the angle between the sides of each V-shaped wing is substantially equal to 90°. BRIEF DESCRIPTION OF THE DRAWINGS Some embodiments of the present invention are described below purely as a non-limiting example, with the aid of the accompanying drawings, in which: figures 1 , 2, 3 are respectively a front, plan and side view of a rectilinear supporting element for the sliding of slides mounted on rolling members, according to a preferred aspect of the present invention; figure 4 shows, in a side view, a phase of laying of a linear guide comprising two supporting elements of the type illustrated in figures 1 to 3; figure 5 shows a front view of a supporting element, in a further embodiment of the present invention, in which a rolling roller of a translating slide is housed; and figure 6 is a schematic perspective view of a supporting element, according to another aspect of the present invention. DETAILED DESCRIPTION OF SOME EMBODIMENTS OF THE INVENTION Figures 1 to 3, according to a preferred aspect of the present invention, show a concave supporting element 1 , with rectilinear development, of a linear guide for the translation of slides or cursors mounted on rolling members, such as roller pins (rolling) or ball bearings. The supporting element 1 , which in the figures is of the type with a thin cross section with a C-shaped profile, comprises a core portion 2 at the ends of which two symmetrical V-shaped wings 3a, 3b extend, defining, with the core 2, the concavity of the element 1. The internal surfaces of each of the V-shaped wings 3a and 3b, or the surfaces facing the concavity of the supporting element 1 , form a sliding race, respectively race 6a for wing 3a and race 6b for 3b, inside which one or more rolling members, such as rolling members with rollers, needles or balls, can be housed and translate according to a known technique. The sliding races 6a, 6b extend axially along the entire length of the supporting element 1 and the two arms of the V-shaped wing, of which they are composed, subtend an angle a which, as will be explained hereunder, is advantageously greater than 60° and preferably equal to 90°. Along the core 2 of the supporting element 1 , moreover, holes 7a, 7b are made to allow the supporting element 1 to be anchored, using for example screws or bolts, to a fixed load-bearing structure, in relation to which a mobile element (not shown) is to be moved, which is in turn anchored to the slide(s) coupled to the supporting element 1. The supporting element 1 , according to the present invention, also comprises means 4a, 4b, 4c, 5a, 5b, 5c for coupling to another supporting element to extend the sliding races 6a, 6b. In particular, the means 4a, 4b, 4c and 5a, 5b, 5c allow mechanical connection between the head of a first supporting element 1 and the tail of a second supporting element in the same direction in which the sliding races 6a, 6b extend.

In the specific embodiment in figures 1-3, the connection means comprise one or more seats 4a, 4b, 4c made in an end section of the supporting element 1 and one or more corresponding pins 5a, 5b, 5c produced projecting from the other end section of the element 1.

The pins 5a, 5b, 5c, moreover, are shaped in such a way as to engage in seats shaped identically to the seats 4a, 4b, 4c, possibly with slight interference, and so that they guarantee continuity of the sliding races 6a, 6b in the passage from one supporting element to the consecutive one. In the shape of the supporting element 1 shown in figures 1-3, in which the element 1 is substantially a thin section beam with a C- shaped profile with rectilinear development, the pins 5a, 5b, 5c coupling to seats shaped like the seats 4a, 4b, 4c must therefore guarantee coaxiality and compliance with geometric tolerances in the connection of two consecutive supporting elements. With reference to figure 4, a linear guide for the translation of slides mounted on rolling members, according to a particular aspect of the present invention, comprises two supporting elements 1 , 101 , of the beam type with a thin section with C-shaped profile, each of which is provided at its ends with reciprocal coupling means. In greater detail, the supporting element 1 comprises, respectively at its ends, projecting pins 5a, 5c and corresponding seats 4a, 4c, and analogously the supporting element 101 comprises pins 105a, 105c and seats 104a, 104c in its ends.

The elements 1 , 101 , the pins 5a, 105a and 5c, 105c, the seats 4a, 104a and 4c, 104c are substantially identical to one another. Coupling between the head end provided with pins 105a, 105c of the supporting element 101 and the tail end of the element 1 with the seats 4a and 4c, by means of inserting the pins 105a, 105c inside the seats 4a, 4c, consents coaxial connection of the two elements 1 , 101 and consequently the continuation, without any interruption, of the sliding races 6a, 106a and 6b, 106b. In this way, sliding inside the races 6a, 6b, 106a, 106b, of a rolling member, such as the type with rollers, can take place without any interruption.

In order to connect the two consecutive supporting elements 1 , 101 permanently, after they have been mechanically coupled using the means 4a, 4c, 105a, 105c, it is possible, as will be further referred to hereunder, to weld their coupled end sections.

To lay the linear guide in figure 4, therefore, after having inserted the pins 105a, 105c of the first element 101 inside the corresponding seats 4a, 4c of the second element 1 , the two coupled ends of the supporting elements 1 , 101 can be welded and subsequently, for example through the holes 7a, 7b provided on the core 2 and bolts or screws, not shown, the guide obtained in this manner can be fixed to a load-bearing structure. Obviously, if the length of the linear guide required is not attained with the two elements 1 and 101 alone further supporting elements may be added, coupling them to the first two as described above.

The modular nature of this embodiment, and the consequent laying technique, makes it possible to produce the structural elements 1 , 101 in only a few sizes, with limited dimensions, and then couple them to one another, as described above, to produce the linear guide desired. This makes it possible, with a limited production of structural elements of different lengths, to satisfy substantially all dimensional requirements relative to the length of the linear guides in different applications.

Consequently, thanks to this modularity, it is not necessary to produce particularly long structural elements, with consequent storage and laying problems, nor is it necessary to produce these elements in a plurality of different sizes, with increases in costs caused by storage, as the structural elements may be produced in a few sizes only which nonetheless satisfy, as the modules can be reciprocally coupled, the most common requirements as regards the length of linear guides. Moreover, owing to the standardization of lengths requested in many applications for linear guides, it is possible to limit the scraps produced when a structural element must in any case be cut, by producing these structural elements with lengths equal to submultiples of the standard lengths requested. The linear guides according to the present invention may be employed for example as guides for the sliding of doors or drawers in relation to load-bearing structures (or skeleton), for the frame of a motor vehicle seat, or in a wide range of different applications, and may also comprise just one supporting element of the type described above.

Figure 5 shows a front view of a structural element 201 , according to a further embodiment of the invention, composed of a beam with a thin section with a concave profile, having a core 202 and two V-shaped end wings 203a and 203b defining sliding races 206a and 206b for rollers 210 connected to a sliding slide or cursor (not shown). The concave beam 201 , at its two end sections, has pins and seats 204a, 204b, 204c for coupling to another beam to extend the sliding races 206a and 206b. As already shown in the embodiment in figure 1 , the arms of the V- shaped wings subtend an angle a which is greater than 60° and preferably equal to 90°.

In fact, these values of the angle a consent optimum coupling, substantially according to a continual line of contact, between the rolling members of the slides and the races 206a, 206b and simultaneously allow the use of rollers or ball bearings commonly available on the market, thus reducing the cos^s to produce the slide without however decreasing the efficiency of the linear guide. Moreover, the geometry obtained, especially when the angle a is equal to 90°, allows the guide to sustain symmetrical loads according to the vertical and horizontal axes.

It is also possible to apply the same concept of modularity to the internal sliding elements (slides), provided for example with rollers 210, to increase the number of slides in use in a simple manner and thus allow the designer to increase the loads acting on the system or to increase the coefficient of safety of the sliding part. Finally, figure 6 shows a perspective view of another structural element 301 , modular, composed of a concave section bar with a core portion 302, two V-shaped end wings 303a and 303b defining sliding races 306a and equipped with coupling seats 304a, 304b, 304c, 304d. According to an advantageous aspect of the present invention, moreover, each modular supporting element 1 , 101 , 201 , 301 is produced employing at least one thermoplastic material, which may be reinforced with glass fibre or carbon, and in particular chosen from polyamides (nylon), polycarbonates, ABS and thermoplastic polyurethanes. The production of the guides in thermoplastic material, which to date prejudicially does not seem to have been undertaken by other operators in the sector, entails considerable simplicity in the production of the structural element, even if its shape is not basic, such as by thermoforming or injection moulding, satisfaction of the mechanical characteristics required, and in particular of the load capacities, and there is no need to lubrication of the sliding races, as self-lubricating materials may be used.

Relative elasticity of the material advantageously allows a substantial decrease in the level of noise caused by sliding, decreasing this by 80% in terms of perceived sound power in relation to the noise detected using traditional metal guides (values measured in laboratory tests by the Applicant) .

It is also possible to use of two or more thermoplastic materials to produce, for example by co-moulding (or co-injection), the supporting elements, just as it is possible to produce supporting elements with an internal reinforcing sheet (for example in metal or composite material) to which the coating surfaces in thermoplastic material are applied, preferably by moulding.

The use of thermoplastic materials in a sandwich with a reinforcing sheet, preferably metal, provides the guides with greater structural resistance both to static loads (the weight of slides), and to dynamic stresses, without this prejudicing the excellent coefficient of friction and the desired features of self-lubrication, soundproofing and low corrodibility and wear of the guides in thermoplastic material. The presence of a metal sheet placed inside the thermoplastic material, moreover, may stiffen the supporting elements of which the guide is composed, without , however reducing the flexibility of the latter, often requested in many applications. The use, according to another preferred aspect of the present invention, of internal sheets produced in materials other than metal, for example composite materials such as glass fibre, carbon or boron structures, co-moulded with an external layer of thermoplastic material, makes it possible to combine considerable structural rigidity, provided by these sheets in composite fibres, with the self-lubrication and anti-corrosion characteristics of the coating thermoplastics.

Moreover, the use of thermoplastic materials, even only to coat the internal reinforcing sheet, makes it possible to use particularly simple and industrially efficient techniques to fix the modules, such as ultrasonic welding or bonding, after mechanical coupling of the connected end sections of two consecutive structural elements.

According to a particular embodiment of the invention, one or more magnetically active elements, for example in the form of pads, may be placed inside the thermoplastic or composite material; these elements are coupled to corresponding magnetically active means which can be fitted on the slides to produce linear magnetic motors provided inside these slides.

Alternatively, it is possible to produce these modular supporting elements 1 , 101 , 201 , 301 in metal, such as steel, by pressing or forging, without employing techniques such as drawing or extrusion normally used to produce these elements.

Claims

CLAIMS Linear guide for the translation of slides on rolling members, of the type comprising one or more concave supporting elements, the supporting element or each of the supporting elements defining at least one sliding race for said slides, characterized in that said supporting element or each of said supporting elements comprises means for coupling to another of said supporting elements to extend said at least one sliding race. Linear guide as claimed in claim 1 , characterized in that said means for coupling comprises, at one end section of the supporting element, one or more axial seats and at the other end section of the supporting element pins engagable in said one or more seats. Linear guide as claimed in either of the claims 1 or 2, characterized in that said supporting element is produced employing at least one thermoplastic material. Linear guide as claimed in any of the previous claims, characterized in that said supporting element is produced employing at least one internal reinforcing sheet coated with one or more layers of at least one thermoplastic material. Linear guide as claimed in claim 4, in which said internal reinforcing sheet is produced in a metal or composite material. Linear guide as claimed in claim 4 or 5, in which said supporting element is produced by moulding on said internal sheet one or more layers of at least one thermoplastic material. Linear guide as claimed in any of the claims from 3 to 6, characterized in that said thermoplastic material is a polymer chosen from polyαmides, polycarbonates, ABS and thermoplastic polyurethanes. Linear guide as claimed in any of the claims from 3 to 7, characterized in that said supporting element is produced by co-moulding employing two or more thermoplastic materials. Linear guide as claimed in any of the claims from 3 to 7, wherein said supporting element is produced by thermoforming or injection moulding. Linear guide as claimed in any of the previous claims, characterized in that said supporting element is produced employing at least one composite material. Linear guide as claimed in claim 10, characterized in that said supporting element is produced by co-moulding. Linear guide as claimed in any of the claims from 3 to 1 1 , characterized in that it comprises, inside surface layers in thermoplastic or composite material, magnetically active elements. Linear guide as claimed in claim 1 or 2, characterized in that said rectilinear supporting element is produced in metal material. Linear guide as claimed in claim 13, in which said supporting element is produced by pressing or forging. Linear guide as claimed in any of the previous claims, wherein said concave supporting elements are beams with a thin section with C-shaped profile with rectilinear development and said sliding races extend axially for the length of said beams with a thin section. Linear guide as claimed in any of the previous claims, characterized in that said linear guide comprises at least two of said supporting elements reciprocally coupled to extend the sliding race, fixed by welding or bonding or mechanical interference of parts. Linear guide as claimed in either of the claims 15 or 16, characterized in that the profile of said one or more supporting elements comprises a central core part and two V-shaped wings provided at the ends of the core part, the angle between the sides of each V-shaped wing being greater than 60°. Linear guide as claimed in claim 17, characterized in that said angle between the side of each V-shaped wing is substantially equal to 90°.