JP3593778B2 - Feed screw device lubricant supply device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an improvement in a lubricant supply device used for a screw transmission device such as a rolling screw such as a ball screw or a sliding screw such as a square screw, a so-called feed screw device.
[0002]
[Prior art]
For example, as shown in FIG. 6, a ball screw conventionally generally used as a feed screw device corresponds to a screw shaft 1 having a spiral screw groove 1b on an outer peripheral surface 1a and a screw groove of the screw shaft. And a nut 2 screwed to the screw shaft 1 via a number of balls 3 having a thread groove 2b to be formed. The space 4 between the outer peripheral surface 1a of the screw shaft 1 and the inner peripheral surface of the nut 2 is filled with a lubricant such as grease or lubricating oil to be lubricated. An annular recess 5 is formed at the end of the nut 2 for the purpose of preventing the filled lubricant from flowing out to the outside quickly and preventing foreign substances such as dust from entering the nut 2. In some cases, a seal 6 is fitted to and attached thereto (seal-type ball screw).
[0003]
The seal 6 of the conventional feed screw device has a helical projection 6a on its inner peripheral surface that engages with the thread groove 1b of the screw shaft 1, and seals 6 and 6 at both ends of the nut and the inner surface of the nut 2 are provided. A region inside the nut surrounded by the outer surface of the screw shaft 1 is defined as a lubricant enclosing region.
[0004]
[Problems to be solved by the invention]
However, in the conventional feed screw device described above, there is a small gap C between the inner peripheral surface of the seal 6 and the outer peripheral surface of the screw shaft 1 (that is, the seal 6 is not in contact with the screw shaft 1 and is not in contact with the screw shaft 1). Therefore, the lubricant in the lubricant-filled region flows out of the nut from the gap C and spreads over almost the entire outer surface of the screw shaft 1. As a result, there is a problem that the area where the lubricant comes into contact with air is enlarged, and oxidative deterioration is promoted. Such a problem occurs not only in the ball screw device but also in other types of feed screw devices such as a square screw device.
[0005]
Therefore, the present invention has been made by paying attention to the problem of the lubricating structure in such a conventional feed screw device, and the lubricant is held in the device without being deteriorated by oxidation, and the necessary An object of the present invention is to provide a feed screw device lubricant supply device which can supply a necessary amount of lubricant to the feed screw device at any time.
[0006]
[Means for Solving the Problems]
The invention according to claim 1 of the present invention provides a screw shaft having a spiral screw groove on an outer peripheral surface, a nut having a screw groove corresponding to the screw groove of the screw shaft and being screwed to the screw shaft. A lubricant supply device used for a feed screw device comprising at least: a rubber or a synthetic resin containing a lubricant, provided on the inner surface of the nut with a number of protrusions contacting the outer surface of the screw shaft. It is characterized by the following.
[0007]
Since the lubricant contained in the lubricant-containing polymer of the lubricant supply device of the present invention does not come into contact with air, it does not deteriorate due to oxidation. Therefore, it is possible to gradually supply clean lubricant to the feed screw device over a long period of time.
Also, a number of protrusions formed on the inner surface of the lubricant supply device of the present invention are in contact with the outer surface of the screw shaft. Therefore, the lead can contact the outer peripheral surface and the thread groove surface even with different screw shafts, and can be commonly used.
[0008]
Further, according to the shape, size, number, etc. of a number of projections formed on the inner surface of the lubricant supply device of the present invention, the supply amount of the contained lubricant to the screw shaft can be adjusted, and Since the contact state of the screw shaft with the thread groove can be changed, it is possible to obtain a highly effective lubrication function by adapting to various aspects of the feed screw device.
Furthermore, by selecting the shape of a large number of projections formed on the inner surface of the lubricant supply device of the present invention, it is possible to obtain a sealing function of preventing foreign substances from entering from the outside.
[0009]
Hereinafter, a lubricant-containing rubber or synthetic resin material used in the lubricant supply device of the present invention will be described in detail.
The rubber or synthetic resin used in the lubricant supply device of the feed screw device of the present invention is a poly-α-olefin-based polymer having basically the same chemical structure as polyethylene, polypropylene, polybutylene, polymethylpentene and the like. Synthetic resins selected from the group, as lubricants, paraffinic hydrocarbon oils such as poly-α-olefin oils, naphthenic hydrocarbon oils, mineral oils, ether oils such as dialkyl diphenyl ether oils, phthalate esters and trimellitate esters The raw material is prepared by injection molding a raw material prepared by mixing any one of the above ester oils or the like in the form of a single oil or a mixed oil, and an antioxidant, a rust inhibitor, a defoaming agent is added to the lubricant in advance. And various additives such as extreme pressure agents.
[0010]
The composition ratio of the lubricant-containing rubber or synthetic resin member is 20 to 80% by weight of a polyolefin-based resin with respect to the total weight, and 80 to 20% by weight of a lubricant (to which a compound reactive film forming compound is added, the same applies hereinafter). %. When the polyolefin resin is less than 20% by weight, a certain level of hardness and strength cannot be obtained. When the polyolefin-based resin exceeds 80% by weight (that is, when the amount of the lubricant is less than 20% by weight), the amount of the lubricant is too small, and the lubricating function deteriorates early.
[0011]
The synthetic resin group has the same basic structure but different average molecular weights, and ranges from 1 × 10 ^{3 to} 5 × 10 ⁶ . Among them, those having a relatively low molecular weight having an average molecular weight of 1 × 10 ³ to 1 × 10 ⁶ and those having an ultrahigh molecular weight of 1 × 10 ^{6 to} 5 × 10 ⁶ are used alone or mixed as necessary. Used.
In order to improve the mechanical strength of the lubricant-containing rubber or synthetic resin member of the present invention, the following thermoplastic resin and thermosetting resin may be added to the above-mentioned poly α-olefin resin.
[0012]
As the thermoplastic resin, resins such as polyamide, polycarbonate, polybutylene terephthalate, polyphenylene sulfide, polyether sulfone, polyether ether ketone, polyamide imide, polystyrene, and ABS resin can be used.
As the thermosetting resin, resins such as unsaturated polyester resin, urea resin, melamine resin, phenol resin, polyimide resin, epoxy resin and the like can be used.
[0013]
These resins may be used alone or as a mixture.
In order to disperse the polyolefin-based resin and other resins in a more uniform state, a suitable compatibilizer may be added as necessary.
Further, a filler may be added to improve the mechanical strength. For example, calcium carbonate, magnesium carbonate, inorganic whiskers such as potassium titanate whiskers and aluminum borate whiskers, or glass fibers and asbestos, inorganic fibers such as metal fibers and the like, and those obtained by braiding them in a cloth form, and organic compounds. , Carbon black, graphite powder, carbon fiber, aramid fiber, polyester fiber, or the like.
[0014]
Further, for the purpose of preventing deterioration of the polyolefin-based resin due to heat, an anti-aging agent such as N, N'-diphenyl-P-phenylenediamine, 2,2'-methylenebis (4-ethyl-6-t-butylphenol), For the purpose of preventing deterioration due to light, 2-hydroxy-4-n-octoxybenzophenone, 2- (2′-hydroxy-3′-tert-butyl-5′-methyl-phenyl) -5-chlorobenzo. An ultraviolet absorber such as triazole may be added.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, the configuration will be described. FIG. 1 shows an embodiment of a lubricant supply device alone according to the present invention, in which (a) is a perspective view, and (b) is an inner surface portion in which a part of an outer surface is cut away. FIG. The lubricant supply device 10 is formed by, for example, injection molding using the above-mentioned lubricant-containing rubber or synthetic resin, has a short cylindrical outer shape, and has a large number of protrusions 11 on its inner peripheral surface. have. The protrusions 11 of this embodiment are trapezoidal cross-section protrusions protruding from the inner peripheral surface of the cylinder toward the center portion, and a plurality of protrusions are radially projected at equal intervals, in parallel. However, the shape of the protrusion 11 shown in FIG. 1 is an example, and various other shapes can be adopted.
[0016]
2 (1) to 2 (8) illustrate a modified example of the projection 11 corresponding to FIG. 1 (b). 2 (1) to 2 (4) show examples of pleated projections having oblique lines (1), arc shapes (2), wavy shapes (3), and herringbone shapes (4). FIGS. 2 (5) to 2 (8) show examples of brush-like projections having an intermittent axis parallel shape (5), an intermittent oblique line shape (6), an axis parallel broken line shape (7), and an oblique broken line shape (8). is there. The projection shape, the projection size such as the thickness and the projection length of each projection, the number of projections (density), and the like are determined by the type and size of the feed screw device to be mounted, the shape of the screw, the lead, the thread groove depth, It can be appropriately selected according to the feed speed and the like.
[0017]
FIG. 2 illustrates an example in which the shape and size of each of the projections 11 in one lubricant supply device 10 are all uniform. However, the present invention is not limited to this, and a plurality of types of different shapes and sizes are used. Protrusions may be appropriately combined and provided.
Next, the operation will be described.
As shown in FIG. 3, the lubricant supply device 10 is fitted into an annular recess 5 at an end of a nut 2 of a ball screw device, for example, a feed screw device, and is fixed and attached with a screw 12 for preventing rotation. I do. In this case, since a large number of protrusions 11 are formed in small increments, even when the lead of the screw of the feed screw device is different as shown in FIGS. If so, each projection 11 can be easily deformed and come into contact with the outer peripheral surface and the groove surface of the screw shaft 1 in the same manner. FIG. 4 shows a state in which the protrusions 11 of the lubricant supply device 10 change the amount of bending thereof in accordance with the contact position with the screw shaft 1 and the tips thereof are in close contact with the outer peripheral surface 1a of the screw shaft and the screw groove 1b, respectively. Is represented.
[0018]
As described above, according to the lubricant supply device 10 of the present invention, the lubricant supply device 10 of the same size can easily follow a change in the screw lead of the feed screw device. Can be used in common.
In this way, the lubricant supply device 10 mounted with the projection 11 on the inner surface brought into contact with the outer peripheral surface (land portion) 1a and the thread groove 1b of the screw shaft 1 causes the lubricant to elapse with the rotation of the screw shaft 1 over time. And gradually spreads from the contact portion of the projection 11 to the screw shaft. Therefore, the feed screw device can maintain a good lubrication state for a long period of time.
[0019]
Since the lubricant contained in the lubricant-containing rubber or the synthetic resin constituting the lubricant supply device 10 does not come into contact with air, it does not deteriorate due to air oxidation. Therefore, it is possible to always supply clean lubricant to the feed screw device for a long time.
In addition, the amount of the lubricant contained can be supplied to the screw shaft 1 in accordance with the shape and number of the large number of projections 11 on the inner surface of the lubricant supply device 10. For example, the number of projections 11 is large. As the surface area increases, the supply amount of the lubricant increases. Further, the contact state of the screw shaft 1 with the screw groove 1b can be changed. For example, the finer the protrusions 11 and the greater the number, the better the change in the screw groove. High lubrication function can be obtained.
[0020]
Further, the lubricant supply device 10 of the present invention enhances the sealing performance by selecting the shape of a large number of projections 11 formed on the inner surface thereof, and in addition to the lubricant supply function, prevents the entry of fine foreign matter from the outside. It can also be expected to function as a blocking seal.
Note that a lubricant such as grease may be sealed in the nut 2 in advance, and the lubricant supply device 10 of the present invention may be attached to both ends of the nut 2. In this case, a phenomenon in which the lubricant in the lubricant-filled region flows out of the nut through a minute gap C between the outer peripheral surface of the screw shaft 1 and the seal 6 of the conventional ball screw device shown in FIG. Can also be suppressed.
[0021]
FIG. 5 shows another embodiment.
In this example, the notch 20 is provided in the cylindrical body of the lubricant supply device 10 of FIG. 1, and there is an advantage that the assembling work for mounting the lubricant through the screw shaft 1 is facilitated. Other functions and effects are the same as those of the first embodiment.
In each of the above embodiments, the case where the feed screw device is exclusively applied to a ball screw device has been described. However, the present invention can be similarly applied to a slide screw device having no ball.
[0022]
【The invention's effect】
As described above, according to the present invention, a lubricant supply device made of rubber or synthetic resin containing a lubricant and having a large number of protrusions on its inner surface is attached to the end of the nut of the feed screw device, and the protrusions are provided. Is brought into contact with the outer surface of the screw shaft, so that the lubricant contained in the lubricant-containing rubber or the synthetic resin gradually oozes out over time and spreads from the contact portion of the projection 11 to the screw shaft. Therefore, there is an effect that the feed screw device can be maintained in a good lubrication state for a long period of time.
[0023]
Moreover, since the lubricant contained in the lubricant-containing rubber or synthetic resin does not come into contact with air and does not deteriorate due to air oxidation, clean lubricant is always supplied to the feed screw device for a long period of time. The effect of being able to continue is obtained. Further, since the inner surface of the lubricant supply device is provided with a large number of projections, it can be commonly used for feed screw devices having different leads, which is extremely convenient in practice.
[0024]
In addition, by adjusting the shape, number, size, and the like of a number of protrusions on the inner surface of the lubricant supply device, the contact state between the protrusions and the thread groove, the supply amount of the lubricant, and the like can be freely changed. The most effective lubrication function can be provided by adapting to the feed screw device of (1).
Furthermore, the lubricant supply device of the present invention can improve the sealing performance by selecting the shape of a large number of projections formed on the inner surface thereof, and in addition to the lubricant supply function, intrusion of fine foreign matter from the outside. This also has the effect of also having a function as a seal for preventing the occurrence of a gas.
[0025]
In addition, by making a notch in the lubricant supply device of the present invention as appropriate and making it expandable, an effect of improving the ease of assembly can be obtained.
[Brief description of the drawings]
FIG. 1A is a perspective view of an embodiment of a lubricant supply device according to the present invention, and FIG. 1B is a diagram of a projection on an inner surface in which an outer peripheral portion is cut away.
FIG. 2 is a view showing various modified examples of a projection 11 illustrated in correspondence with FIG. 1 (b).
FIG. 3 is a perspective view showing a usage mode of the lubricant supply device of FIG. 1;
FIG. 4 is a front view illustrating the operation of the one shown in FIG.
FIG. 5 is a perspective view of another embodiment of the lubricant supply device of the present invention.
FIG. 6 is a half sectional view illustrating a lubrication structure of a ball screw device which is a conventional feed screw device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Screw shaft 1a Outer peripheral surface 1b Screw groove 2 Nut 10 Lubricant supply device 11 Projection

Claims (1)

A lubricant used for a feed screw device comprising at least a screw shaft having a helical screw groove on the outer peripheral surface, and a nut having a screw groove corresponding to the screw groove of the screw shaft and being screwed to the screw shaft. A lubricant for a feed screw device, comprising: a supply device, which is made of a rubber or a synthetic resin containing a lubricant, and is provided on the nut with an inner surface provided with a large number of protrusions that contact an outer surface of the screw shaft. Feeding device.

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