JP3796972B2 - Lubricator for ball screw - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lubrication device for a ball screw, and more particularly to a lubrication device capable of supplying a lubricant to a ball screw over a long period of time.
[0002]
[Prior art]
A ball screw mechanism is known as a mechanism for converting rotational motion into linear motion. In the ball screw mechanism, a ball nut having a thread groove on the inner periphery is opposed to a screw shaft having a thread groove on the outer periphery, and the ball nut is rotated by rotating the screw shaft. It moves in the direction.
[0003]
Incidentally, a lubricant such as grease is usually applied between the thread groove and the ball so as to prevent heating due to wear or friction of the thread groove and the ball. However, grease or the like needs to be periodically captured because its function as a lubricant deteriorates in a relatively short period of time due to the effects of temperature, moisture, foreign matter, abrasion powder, and the like. In order to improve the efficiency of such replenishment work, an apparatus for replenishing lubricant has been developed.
[0004]
However, such a replenishing device is expensive, and piping for refueling must be newly installed, which increases costs. In addition, inspection and maintenance work of the replenishing device is necessary, which is inconvenient in handling.
[0005]
In contrast to such a conventional technique, a configuration in which a lubricant-containing polymer member is disposed between a screw shaft of a ball screw and a ball nut is also considered. Such a lubricant-containing polymer member has such a characteristic that the lubricant gradually oozes out over a long period of time. Therefore, even after the lubrication function of grease or the like applied to the thread groove in the initial stage deteriorates, the lubricant-containing polymer member Lubrication between the screw groove and the ball can be performed by the lubricant exuding from the member. Thereby, the lubrication of the ball screw can be made almost maintenance-free.
[0006]
[Problems to be solved by the invention]
By the way, as will be described later, a point of interest when such a lubricant-containing polymer member is used has been pointed out. FIG. 16 is a cross-sectional view showing a ball screw using a lubricant-containing polymer member. In FIG. 16, a cylindrical ball nut 2 is arranged around the screw shaft 1. A lubricant-containing polymer member 10 is disposed between the inner peripheral surface 5 a of the annular recess 5 formed on the end surface of the ball nut 2 and the screw shaft 1. The lubricant-containing polymer member 10 also has a sealing function, and grease is sealed inside the ball nut 2.
[0007]
A garter spring 15 is inserted into the outer peripheral surface 10 b of the lubricant-containing polymer member 10. Since the garter spring 15 presses the lubricant-containing polymer member 10 in a radial direction toward the screw groove 1b of the screw shaft 1 with a constant pressure, the inner peripheral surface of the lubricant-containing polymer member 10 is worn even during long-term operation. Even so, proper contact with the screw shaft 1 is always maintained and good lubrication is ensured.
[0008]
FIG. 17 is a view of the ball screw of FIG. 16 taken along the line IXV-IXV and viewed in the direction of the arrow. FIG. 18 is a view of the ball screw of FIG. 17 cut along line XV-XV and viewed in the direction of the arrow. In FIG. 17, the lubricant-containing polymer member 10 is composed of an upper half part 10c and a lower half part 10d each having a substantially semicylindrical shape.
[0009]
The upper half portion 10c and the lower half portion 10d are in close contact with the entire outer periphery of the screw shaft 1, and a gap A is formed between the upper half portion 10c and the lower half portion 10d. It has become.
[0010]
On the other hand, as shown in FIG. 18, the convex portion 10 a of the lubricant-containing polymer member 10 is arranged in close contact with the outer periphery of the screw groove 1 b of the screw shaft 1.
[0011]
Here, as shown in FIGS. 16 and 17, when the convex portion 10a of the lubricant-containing polymer member 10 is brought into close contact with the screw groove 1b and the screw shaft 1 reciprocates, the lubricant adhered in the screw groove 1b. However, there arises a problem that the sliding portion of the lubricant-containing polymer member 10 is scraped to the stroke end.
[0012]
On the other hand, as shown in FIG. 17, when the end portion of the convex portion 10a (the portion facing the space A) is in close contact with the screw groove 1b, the lubricant adhering to the screw groove 1b is removed. Scrapes into the space A, so-called scraper action occurs. The lubricant scraped into the space A is hardly used for lubrication.
[0013]
In this way, due to the shape of the lubricant-containing polymer member 10, the amount of lubricant that should be supplied to the thread groove is reduced, and sufficient lubrication can be achieved particularly in applications where the ball screw supports a high load. As a result, there is a risk of causing abnormal wear of thread grooves and balls, premature surface peeling, and the like.
[0014]
The present invention has been made paying attention to such a conventional problem, and an object of the present invention is to provide a ball screw lubricating device capable of performing sufficient lubrication even in high load applications.
[0015]
[Means for Solving the Problems]
In order to achieve the above object, a ball screw lubricating device according to claim 1 of the present invention is disposed between a ball nut and a screw shaft. Grease filled type A lubrication device for a ball screw, which is in sliding contact with only the outer diameter portion of the screw shaft in at least one of both ends of the ball nut and a space including a ball non-passing space inside the ball nut. Supply the lubricant A lubricant-containing polymer member was attached. According to this lubricating device, the lubricant containing polymer member can prevent the lubricant attached to the screw groove from being scraped off during the reciprocating operation of the screw shaft, and effectively retain the lubricant attached to the screw groove. It can be done.
[0016]
According to a second aspect of the present invention, there is provided a lubricating device for a ball screw according to the first aspect, wherein the lubricant-containing polymer member that is in sliding contact with the outer diameter portion of the screw shaft is divided into a plurality of portions in the circumferential direction. Was made larger than the ball screw outer diameter. According to this lubrication apparatus, since a clearance is formed between the outer diameter portion of the screw shaft and the lubricant-containing polymer member, the effect of retaining the lubricant can be further enhanced.
[0017]
According to a third aspect of the present invention, there is provided a lubricating device for a ball screw according to the second aspect, wherein a lubricant retaining chamfer is formed at an inner diameter side end portion of a split surface of the lubricant-containing polymer member. According to this lubrication apparatus, even if the lubricant adhering to the thread groove is scraped off due to rotation of the lubricant-containing polymer member or the like, the lubricant is retained in the lubricant retaining chamfer and used for lubrication.
[0018]
According to a fourth aspect of the present invention, there is provided the ball screw lubricating device according to the first to third aspects, wherein a seal-type seal is provided on an outer portion of the lubricant-containing polymer member in the ball nut. According to this lubricating device, the sealing type seal prevents leakage of the lubricant to the outside of the ball nut and intrusion of foreign matter into the ball nut, and the sealing type seal by the lubricant exuding from the lubricant-containing polymer member. The lip is also lubricated.
[0019]
Further, if the lubricant-containing polymer member is formed so as to be in sliding contact with only the outer diameter portion of the screw shaft, it is not necessary to match the shape of the lubricant-containing polymer member with the shape of the thread groove. In order to manufacture a lubricant-containing polymer member having a protrusion corresponding to a thread groove, it is necessary to first form a mold when molding with a mold. However, in order to form a mold that can accurately mold the protrusion corresponding to the thread groove, it is usually necessary to correct the mold several times based on trial and error in consideration of the shrinkage rate in the molded product of the lubricant-containing polymer member. It becomes. On the other hand, in order to form the protruding portion on the lubricant-containing polymer member by machining, it is necessary to make a special tool that matches the shape of the protruding portion in advance. In any case, the cost will increase. On the other hand, for example, if the protrusion corresponding to the screw groove is not formed, there is no need to make the above-mentioned mold or tool, and only the shaft diameter of the ball screw shaft needs to be considered, leading to cost reduction. Become.
[0020]
The lubricant-containing polymer applied to the present invention is a synthetic resin selected from the group of polyolefin resins having basically the same chemical structure, such as polyethylene, polypropylene, polybutylene, polymethylpentene, and the like. Paraffinic hydrocarbon oil such as α-olefin oil, naphthenic hydrocarbon oil, mineral oil, ether oil such as dialkyldiphenyl ether oil, ester oil such as phthalate ester, etc. The raw material prepared by heating is plasticized by heating above the melting point of the resin, and then solidified by cooling Condition The lubricant may be prepared by adding various additives such as an antioxidant, a rust inhibitor, an antiwear agent, a foam remover, and an extreme pressure agent in advance to the lubricant.
[0021]
The composition ratio of the lubricant-containing polymer is 10 to 50% by weight of polyolefin resin and 90 to 50% by weight of lubricant with respect to the total weight. When the polyolefin-based resin is less than 10% by weight, hardness / strength exceeding a certain level cannot be obtained, and it becomes difficult to maintain the initial shape when a load is applied. Further, when the polyolefin resin exceeds 50% by weight (that is, when the lubricant is less than 50% by weight), the supply of the lubricant is reduced and the life of the ball screw is shortened.
[0022]
The group of the synthetic resins has the same basic structure but different average molecular weights, and is 700 to 5 × 10. ⁶ Range. Average molecular weight 700-1 × 10 ^Four Classified as wax (for example, polyethylene wax) and average molecular weight of 1 × 10 ^Four ~ 1x10 ⁶ A relatively low molecular weight and an average molecular weight of 1 × 10 ⁶ ~ 5x10 ⁶ Are used alone or in admixture if necessary.
[0023]
A combination of a relatively low molecular weight material and a lubricant provides a lubricant-containing polymer having a certain degree of mechanical strength, lubricant supply capability, and oil retention. Replacing some of these with relatively low molecular weights with those classified as wax increases the affinity with the lubricating oil because of the small difference in molecular weight between those classified as wax and the lubricating oil. As a result, the oil retaining property of the lubricant-containing polymer is improved, and the lubricant can be supplied over a long period of time. However, on the other hand, the mechanical strength decreases. As the wax, in addition to polyolefin resin such as polyethylene wax, any hydrocarbon-based one having a melting point in the range of 100 to 130 ° C. or higher (for example, paraffin-based synthetic wax) can be used.
[0024]
On the other hand, when it is replaced with an ultra-high molecular weight one, the difference in molecular weight between the ultra-high molecular weight and the lubricating oil is large, so the affinity with the lubricating oil is lowered, resulting in a decrease in oil retention. The lubricant oozes out from the lubricant-containing polymer. Thereby, the time to reach the amount of lubricant that can be supplied from the lubricant-containing polymer is shortened, and the life of the ball screw is shortened. However, the mechanical strength is improved.
[0025]
Considering the balance of moldability, mechanical strength, oil retention, and lubricant supply amount, the composition ratio of the lubricant-containing polymer is 0 to 5% by weight classified as wax, and 8 to 48 having a relatively low molecular weight. It is preferable to use 10% by weight, 2 to 10% by weight of ultra high molecular weight, and 10 to 50% by weight in total of the three resins (the balance is 90 to 50% by weight of lubricant).
[0026]
In order to improve the mechanical strength of the lubricant-containing polymer of the present invention, the following thermoplastic resin and thermosetting resin can be added to the above-mentioned polyolefin resin. As the thermoplastic resin, resins such as polyamide, polycarbonate, polybutylene terephthalate, polyphenylene sulfide, polyethersulfone, polyetheretherketone, polyamideimide, polystyrene, and ABS resin can be used.
[0027]
On the other hand, as the thermosetting resin, each resin such as unsaturated polyester resin, urea resin, melanin resin, phenol resin, polyimide resin, and epoxy resin can be used. These resins may be used alone or in combination.
[0028]
Furthermore, in order to disperse the polyolefin resin and other resins in a more uniform state, an appropriate compatibilizing agent may be added as necessary. Moreover, in order to improve mechanical strength, you may add a filler. For example, inorganic whiskers such as calcium carbonate, magnesium carbonate, potassium titanate whisker and aluminum borate whisker, or inorganic fibers such as glass fiber and metal woven fabric and those braided into a cloth shape, and organic compounds, Carbon black, graphite powder, carbon fiber, aramid fiber, polyester fiber, or the like may be added.
[0029]
Further, for the purpose of preventing deterioration of the polyolefin resin due to heat, an anti-aging agent such as N, N′-diphenyl-P-phenyldiamine, 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′-t-butyl-5′-methyl-phenyl) -5-chlorobenzotriazole An ultraviolet absorber such as may be added.
[0030]
The addition amount of all the above additives (other than the polyolefin-based resin and the lubricant) is preferably 20% by weight or less of the total amount of the molding raw material as a whole in order to maintain the supply capability of the lubricant. .
[0031]
The above-described lubricant-containing polymer is solid, unlike grease and lubricating oil, so that water and dust are not mixed therein. Therefore, if the space between the ball nut end and the screw shaft is filled with a lubricant-containing polymer, ingress of water and dust, which causes a reduction in the life of the ball screw, is greatly suppressed in addition to or instead of the seal member. can do.
[0032]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments according to the present invention will be described below with reference to the drawings. FIG. 1 shows a ball screw lubricating device according to a first embodiment of the present invention attached to a ball nut. Status It is sectional drawing shown by. FIG. 2 is a view of the configuration of FIG. 1 taken along line II-II and viewed in the direction of the arrow. FIG. 3 is an enlarged view showing a portion III of the configuration of FIG.
[0033]
In the first embodiment shown in FIG. 1, the ball nut 2 is arranged so as to enclose the screw shaft 1, and the screw groove 2 a formed on the inner periphery of the ball nut 2 and the screw shaft 1 opposed thereto are arranged. A plurality of balls 3 are arranged so as to roll freely between the thread grooves 1b formed on the outer periphery.
[0034]
A cylindrical seal cap 4 is attached to the right end of the ball nut 2 with four bolts 6 via a lubricant-containing polymer member 20. Sleeves 6 a are interposed on the outer periphery of the shaft portion of the bolt 6. A labyrinth seal 7 is attached to the end of the seal cap 4 to prevent foreign matters such as dust from entering through the gap between the screw shaft 1 and the seal cap 4.
[0035]
The lubricant-containing polymer member 20 is formed with a narrow groove 20a on the outer periphery, and the lubricant-containing polymer member 20 is moved toward the outer periphery of the screw shaft 1 with a constant pressure by the garter spring 15 arranged here. Since it is pressed in the radial direction, even if the inner peripheral surface of the lubricant-containing polymer member 20 is worn due to long-term operation, proper contact with the screw shaft 1 is always maintained and good lubrication is ensured. It has become.
[0036]
As shown in FIG. 2, the lubricant-containing polymer member 20 includes an upper half 20b and a lower half 20c that are substantially semicylindrical. Here, the outer diameter of the screw shaft 1 is 40 mm, and the inner diameters of the upper half 20b and the lower half 20c are 40.4 mm. Accordingly, although exaggerated in FIG. 2, only the central portions of the upper half portion 20 b and the lower half portion 20 c are in contact with the outer periphery of the screw shaft 1, and both circumferential ends thereof are the outer periphery of the screw shaft 1. On the other hand, a clearance B (4 places) is formed.
[0037]
In addition, even after the garter spring 15 is attached to the outer periphery of the lubricant-containing polymer member 20, the size of the lubricant-containing polymer member 20 is larger and its rigidity is relatively higher than the elastic force of the garter spring 15. Therefore, the clearance B is not lost. Furthermore, the circumferential end portions of the upper half 20b and the lower half 20c are separated from each other.
[0038]
On the other hand, as apparent from FIG. 3, the inner periphery of the lubricant-containing polymer member 20 has a cylindrical surface shape, and therefore does not have a protrusion that fits into the thread groove 1 b of the screw shaft 1.
[0039]
In the present embodiment configured as described above, when the screw shaft 1 rotates with respect to the ball nut 2, the screw shaft 1 slides with respect to the lubricant-containing polymer member 20. Here, as shown in FIG. 2, the upper half of the lubricant-containing polymer member 20 20b Since a clearance B is formed between both ends in the circumferential direction of the lower half 20c and the outer periphery of the screw shaft 1, the upper half 20b and the lower half are not affected when the screw shaft 1 rotates in any direction. Both end portions of the half portion 20c do not scrape off the lubricant adhering to the outer periphery of the screw shaft 1 (that is, no scraper action occurs), and such lubricant enters the skimmer B. Therefore, the lubricant adhering to the screw shaft 1 is held, and thereby the lubrication between the ball and the screw groove can be ensured.
[0040]
Furthermore, since the lubricant-containing polymer member 20 does not have a protruding portion that fits into the screw groove 1b of the screw 1, the lubricant attached to the screw groove 1b is not scraped out to the outside. In addition, the lubricant adhering to the outer periphery of the screw shaft 1 that has entered the clearance B (FIG. 2) due to the rotation of the screw shaft 1 has an upper half portion 20b and a lower half portion 20c each having a central portion at the screw shaft. Since it is in contact with the outer periphery of 1, the escape area is lost, and it flows into the screw groove 1 b as shown by the arrow in FIG. 3, whereby the lubrication effect can be further enhanced.
[0041]
FIG. 4 is a cross-sectional view similar to FIG. 3 showing the second embodiment of the lubricant-containing polymer member. According to this embodiment, the lubricant-containing polymer member 30 is the same as the above-described embodiment. Differently, a convex portion 30a that enters the screw groove 1b of the screw shaft 1 is provided. The convex portions 30a are not in contact with the inner surface of the thread groove 1b and are separated by a slight gap.
[0042]
With this configuration, the lubricant-containing polymer member 30 has the effect of not scraping the lubricant attached to the thread groove 1b to the outside, as in the above-described embodiment. In addition, since the convex portion 30a is provided in the second embodiment, a labyrinth space is formed between the screw groove 1b and the convex portion 30a. Can be prevented, and can be prevented from entering the ball nut 2.
[0043]
FIG. 5 shows a ball screw lubricating device according to a third embodiment of the present invention attached to a ball nut. Condition It is sectional drawing shown by a state. In the configuration of FIG. 5, in order to make the nut length shorter, the lubricant-containing polymer member 40 is placed in the preload spacer space formed by the preload spacer 2C between the first nut 2A and the second nut 2B. Is provided. In the present embodiment, the configuration and operational effects are the same as those of the first embodiment except that the length in the axial direction is short. Note that the bolt 6 may be brought into direct contact with the lubricant-containing member 40 without providing the cap 4.
[0044]
FIG. 6 is a cross-sectional view similar to FIG. 2, showing a lubricant-containing polymer member according to a fourth embodiment of the present invention. Note that the fourth embodiment will also be described with a focus on differences from the first embodiment shown in FIG. 2, and description of common parts will be omitted.
[0045]
In the present embodiment, the lubricant-containing polymer member 50 is not divided into two parts, but is an integral body having a C-shaped cross section. However, since both ends thereof are spaced apart from the outer periphery of the screw shaft 1 to form a clearance B, the lubricant adhering to the outer periphery of the screw shaft 1 is scraped off as in the first embodiment. There is no.
[0046]
FIG. 7 is a cross-sectional view similar to FIG. 2, showing a lubricant-containing polymer member according to a fifth embodiment of the present invention. Note that the fifth embodiment will also be described with a focus on differences from the first embodiment shown in FIG. 2, and the description of common parts will be omitted.
[0047]
Also in the present embodiment, the lubricant-containing polymer member 60 is not divided into two parts and is an integral part having a C-shaped cross section. A notch 60a is formed. Therefore, in this embodiment, the lubricant-containing polymer member 60 is more easily bent than in the fourth embodiment. This embodiment is effective when the size of the lubricant-containing polymer member is large or a material having high rigidity is used.
[0048]
FIG. 8 is a cross-sectional view similar to FIG. 2, showing a lubricant-containing polymer member according to a sixth embodiment of the present invention. Note that the sixth embodiment will also be described with a focus on differences from the above-described embodiment, and description of common portions will be omitted.
[0049]
In the present embodiment, the cutout 70a formed in a part of the outer peripheral surface of the lubricant-containing polymer member 70 has a V-shaped cross section. Therefore, compared to the above-described embodiment, in this embodiment, the lubricant-containing polymer member 70 is more easily bent.
[0050]
FIG. 9 is a cross-sectional view similar to FIG. 2, showing a lubricant-containing polymer member according to a seventh embodiment of the present invention. FIG. 10 is a perspective view of the main part showing the lower half of the lubricant-containing polymer member. Note that the seventh embodiment will also be described with a focus on differences from the above-described embodiment, and description of common portions will be omitted.
[0051]
In the present embodiment, as in the first embodiment, the lubricant-containing polymer member 20 is composed of an upper half portion 20b and a lower half portion 20c each having a substantially semicylindrical shape. Lubricant-holding chamfers 80 are formed at the inner diameter side ends of the divided surfaces of 20b and lower half 20c, respectively. Further, since the lubricant-containing polymer member 20 is opened in the nut outer diameter direction of the sleeve 6a, a radial toward the outer periphery of the screw shaft 1 of the lubricant-containing polymer member 20 by the garter spring 15 shown in FIG. Direction pressing is performed more effectively.
[0052]
In this embodiment, the screw axis Even when the lubricant-containing polymer member 20 swings or bends and deforms when the 1 rotates, the lubricant is prevented from flowing out to the skimmer A side even if the above-described scraper action is caused by the divided surface. For example, the screw is caused by the oscillation of the lubricant-containing polymer member 20. axis Even if the outer peripheral surface of 1 and the inner peripheral surface of the lower half portion 20c are in close contact with each other and the gap B disappears, the lubricant scraped by the lower half portion 20c is used for retaining the lubricant as shown in FIG. It is retained as a lubricating oil reservoir 81 in the chamfer 80 and is unlikely to flow out to the clearance A side. As a result, the lubricant hardly flows into the space A, and the lubricating oil is gradually supplied from the lubricating oil reservoir 81 to the thread groove 1b side, and good lubrication is performed over a long period of time.
[0053]
FIG. 11 is a cross-sectional view similar to FIG. 2, showing a lubricant-containing polymer member according to an eighth embodiment of the present invention. Note that the eighth embodiment will also be described with a focus on differences from the above-described embodiment, and description of common portions will be omitted.
[0054]
This embodiment has a configuration substantially the same as that of the seventh embodiment, except that the lubricant holding chamfer 80 formed in the upper half 20b and the lower half 20c of the lubricant-containing polymer member 20 is used. Is a so-called R chamfer. Also in the present embodiment, even if the lubricant-containing polymer member 20 swings or bends and deforms when the thread groove 1 rotates and the scraper action is caused by the above-described dividing surface, the same as in the seventh embodiment. The lubricant is prevented from flowing out to the skimmer A side, and good lubrication is performed over a long period of time.
[0055]
FIG. 12 is a cross-sectional view similar to FIG. 2, showing a lubricant-containing polymer member according to a ninth embodiment of the present invention. FIG. 13 is a perspective view of the main part showing the lower half of the lubricant-containing polymer member. Note that the ninth embodiment will also be described with a focus on differences from the above-described embodiment, and description of common portions will be omitted.
[0056]
Also in the present embodiment, a configuration substantially similar to that of the seventh embodiment is adopted, but the chamfering 80 for retaining lubricant covers the entire inner diameter side end portions of the upper half portion 20b and the lower half portion 20c. Instead, it is formed in such a manner that both ends in the axial direction are left as the partition walls 83.
[0057]
The operation of this embodiment is almost the same as that of the seventh embodiment, and even if the scraper action by the dividing surface occurs, the lubricant is prevented from flowing out to the skimmer A side. The outflow of lubricant is also suppressed. That is, as shown in FIG. 13, the lubricant scraped by the lower half portion 20 c is held as a lubricating oil reservoir 81 in the lubricant holding chamfer 80, and also the lower half portion 20 c by the partition wall 83. It will be difficult to flow out from the axial end face. As a result, the lubricant is reliably held in the lubricant holding chamfer 80, and the lubricant is gradually supplied from the lubricant reservoir 81 to the thread groove 1 b side, and good lubrication is performed over a long period of time.
[0058]
FIG. 14 shows a ball screw lubricating device according to a tenth embodiment of the present invention attached to a ball nut. Condition It is sectional drawing shown by a state. In the configuration of FIG. 14, a pair of left and right lubricant-containing polymer members 20 are fitted into the ball nut 2, and hermetic seals 84 are press-fitted outside the lubricant-containing polymer members 20. The sealed seal 84 of the present embodiment is a known seal that continuously contacts the thread groove 1b of the screw shaft 1 and the outer diameter, and when the ball nut 2 moves, the inside of the seal is secured by sliding contact with the screw shaft 1. Seal to.
[0059]
According to this lubrication apparatus, compared with the above-described one using the labyrinth seal, the leakage of lubricant to the outside of the ball nut 2 and the entry of foreign matter into the ball nut 2 are further prevented in each shaft, and the life of the ball screw is reduced. Is greatly extended. Further, since the hermetic seal 84 is always lubricated by the lubricant exuding from the lubricant-containing polymer member 20, the lip portion or the like is hardly worn or damaged, and extremely high durability is ensured.
[0060]
This is the end of the description of specific embodiments, but the aspects of the present invention are not limited to these embodiments. For example, in each of the above embodiments, the lubricant-containing polymer member is slidably contacted only with the outer diameter of the ball screw. However, as shown in FIG. A protruding portion 85 that partially slidably contacts the groove 1b may be formed. In this case as well, substantially the same effects as those of the above embodiments can be obtained. Further, the arrangement and fixing method of the lubricant-containing polymer member and the specific structure of the ball screw can be appropriately changed within the scope of the present invention.
[0061]
【The invention's effect】
According to the lubricating device for a ball screw of the present invention, at least one of the both ends of the ball nut and the space including the ball non-passing space inside the ball nut is in sliding contact with only the outer diameter portion of the screw shaft. Since the lubricant-containing polymer member is attached, it is possible to prevent the lubricant attached to the screw groove from being scraped off by the lubricant-containing polymer member when the screw shaft reciprocates, and the lubricant attached to the screw groove. Can be effectively retained. In addition, the lubricant-containing polymer member that is in sliding contact with the outer diameter portion of the screw shaft is divided into a plurality of portions in the circumferential direction, and the inner diameter dimension thereof is larger than the outer diameter of the ball screw. Can do. Further, in the lubricant-containing polymer member in which the chamfer for retaining the lubricant is formed at the inner diameter side end portion of the dividing surface, the lubricant adhered to the outer periphery of the screw shaft is scraped off by rotation of the lubricant-containing polymer member. However, the lubricant is held in the chamfer for holding the lubricant and used for lubrication.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a ball screw lubricating device according to a first embodiment of the present invention attached to a ball nut.
FIG. 2 is a view of the configuration of FIG. 1 taken along line II-II and viewed in the direction of the arrow.
FIG. 3 is an enlarged view showing a III part of the configuration of FIG. 1;
FIG. 4 shows a second embodiment of a lubricant-containing polymer member with FIG. similar It is sectional drawing.
FIG. 5 is a cross-sectional view showing a ball screw lubricating device according to a third embodiment of the present invention attached to a ball nut.
FIG. 6 is a cross-sectional view similar to FIG. 2, showing a lubricant-containing polymer member according to a fourth embodiment of the present invention.
FIG. 7 is a cross-sectional view similar to FIG. 2, showing a lubricant-containing polymer member according to a fifth embodiment of the present invention.
FIG. 8 is a sectional view similar to FIG. 2, showing a lubricant-containing polymer member according to a sixth embodiment of the present invention.
FIG. 9 is a cross-sectional view similar to FIG. 2, showing a lubricant-containing polymer member according to a seventh embodiment of the present invention.
FIG. 10 is a perspective view of relevant parts for explaining the operation of the seventh embodiment.
FIG. 11 is a sectional view similar to FIG. 2, showing a lubricant-containing polymer member according to an eighth embodiment of the present invention.
FIG. 12 is a cross-sectional view similar to FIG. 2, showing a lubricant-containing polymer member according to a ninth embodiment of the present invention.
FIG. 13 is a perspective view of relevant parts for explaining the operation of the ninth embodiment.
FIG. 14 is a cross-sectional view showing a ball screw lubrication device according to a tenth embodiment of the present invention attached to a ball nut.
15 is a cross-sectional view similar to FIG. 3, showing a partial modification of the lubricant-containing polymer member. FIG.
FIG. 16 is a cross-sectional view showing a conventional ball screw using a lubricant-containing polymer member.
17 is a view of the ball screw of FIG. 16 cut along the line IXV-IXV and viewed in the direction of the arrow.
18 is a view of the ball screw of FIG. 17 cut along line XV-XV and viewed in the direction of the arrow.
[Explanation of symbols]
1 ... Screw shaft
2 ... Ball nut
2A ... 1st nut
2B 2nd nut
2C ... Preload spacer
3 ... Ball
4 ... Seal cap
6 ... Bolt
7. Labyrinth seal
15 ... Garta Spring
20, 30, 40, 50, 60, 70... Lubricant-containing polymer member
80 ... Chamfer for retaining lubricant
84 ... Sealed seal

Claims (3)

In a lubricating device for a grease-filled ball screw disposed between a ball nut and a screw shaft,
And both ends of the ball nut, at least one of the space containing the ball non-passing space in the interior of the ball nut, lubricant-containing polymer member for supplying lubricating oil to sliding contact only outside diameter of the screw shaft A lubricating device for a ball screw, characterized in that 2. The ball screw lubricating device according to claim 1, wherein an outer diameter portion of the screw shaft is an outer periphery of the screw shaft. 2. The ball screw lubricating device according to claim 1, wherein an outer diameter portion of the screw shaft is an outer periphery of the screw shaft and a portion in the vicinity of the outer periphery of the screw groove.

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