JP2000081103A - Lubrication device for ball screws - Google Patents

Abstract

(57) [Problem] To provide a lubricating device for a ball screw which can provide sufficient lubrication even in a high load application. SOLUTION: Since a lubricant-containing polymer member 20 slidingly contacting only an outer diameter portion of a screw shaft 1 is attached to a ball nut 2, the thread groove 1b is reciprocated by the lubricant-containing polymer member 20 when the screw shaft 1 reciprocates. The lubricant attached to the screw groove 1b can be prevented from being scraped off, whereby the lubricant attached to the thread groove 1b can be effectively held.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a lubricating device for a ball screw, and more particularly to a lubricating device capable of supplying a lubricant to a ball screw for a long period of time.

[0002]

2. Description of the Related Art A ball screw mechanism is known as a mechanism for converting a rotary motion into a 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 while a plurality of balls are interposed therebetween, and the ball nut is rotated by rotating the screw shaft, so that the ball nut has an axial line. It moves in the direction.

A lubricant such as grease is usually applied between the thread groove and the ball to prevent the thread groove and the ball from being heated due to wear and friction. However, grease and the like have a reduced function as a lubricant in a relatively short period of time due to the effects of temperature, moisture, foreign matter, abrasion powder, and the like, and thus need to be periodically collected. In order to increase the efficiency of such replenishment work, devices for replenishing lubricant have been developed.

[0004] However, such a replenishing device is expensive, and it is necessary to newly install piping for refueling, which increases the cost. Further, the inspection and maintenance work of the replenishing device is required, which is inconvenient in handling.

[0005] In contrast to such prior art, a configuration in which a lubricant-containing polymer member is disposed between the screw shaft of a ball screw and a ball nut has been considered. Since such a lubricant-containing polymer member has such a property that the lubricant gradually exudes over a long period of time, even after the lubrication function of grease or the like applied to the thread groove in the initial stage is reduced, the lubricant-containing polymer member is not affected. Lubrication between the thread groove and the ball can be performed by the lubricant that has exuded from the member. Thereby, the lubrication of the ball screw can be made almost maintenance-free.

[0006]

However, the following problems have been pointed out in the case where such a lubricant-containing polymer member is used. 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 screw shaft 1 and the inner peripheral surface 5a of the annular concave portion 5 formed on the end surface of the ball nut 2. The lubricant-containing polymer member 10 also has a sealing function, and grease is sealed inside the ball nut 2.

The outer peripheral surface 10b of the lubricant-containing polymer member 10
A garter spring 15 is fitted in. Since the garter spring 15 radially presses the lubricant-containing polymer member 10 toward the thread groove 1b of the screw shaft 1 at a constant pressure, even if the inner peripheral surface of the lubricant-containing polymer member 10 is worn due to long-term operation. Even so, proper contact with the screw shaft 1 is always maintained, and good lubrication is ensured.

FIG. 17 shows the ball screw of FIG.
It is the figure cut | disconnected by IXV line and seen in the arrow direction. FIG.
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 includes an upper half portion 10c and a lower half portion 10d each having a substantially semi-cylindrical shape.

The upper half 10c and the lower half 10d have the entire inner periphery thereof in close contact with the outer periphery of the screw shaft 1, and the upper half 10c
A gap A is formed between the upper half 10d and the lower half 10d.

On the other hand, as shown in FIG. 18, on the outer periphery of the screw groove 1b of the screw shaft 1, the convex portion 1 of the lubricant-containing polymer member 10 is formed.
0a are arranged in close contact.

Here, as shown in FIGS. 16 and 17, when the convex portion 10a of the lubricant-containing polymer member 10 comes into close contact with the thread groove 1b and the screw shaft 1 reciprocates, it adheres in the thread groove 1b. There is a problem that the lubricant that has been scraped off at the stroke end by the sliding portion of the lubricant-containing polymer member 10.

On the other hand, as shown in FIG. 17, when the end portion (the portion facing the space A) of the projection 10a is in close contact with the screw groove 1b without any gap, the lubricant adhering to the screw groove 1b is removed with great effort. A so-called scraper action occurs in which such an end is scraped into the space A. The lubricant scraped out into the space A is hardly used for lubrication.

As described above, due to the shape of the polymer member 10 containing the lubricant, the amount of the lubricant which should be supplied to the thread groove is reduced. In particular, the ball screw is sufficient for supporting a high load. Lubrication cannot be performed, which may lead to abnormal wear of thread grooves and balls, early surface separation, and the like.

The present invention has been made in view of such conventional problems, and has as its object to provide a ball screw lubricating apparatus capable of performing sufficient lubrication even in high load applications. I do.

[0015]

In order to achieve the above object, a ball screw lubricating apparatus according to the first aspect of the present invention comprises a ball screw lubricating device disposed between a ball nut and a screw shaft. A lubricating device, wherein at least one of both ends of the ball nut and a space including a ball non-passing space inside the ball nut, a lubricant-containing polymer member that slides only on an outer diameter portion of the screw shaft; Attached.
According to this lubricating device, the lubricant attached to the screw groove can be prevented from being scraped off by the lubricant-containing polymer member during the reciprocating operation of the screw shaft, and the lubricant attached to the screw groove can be effectively held. I can do it.

According to a second aspect of the present invention, there is provided a ball screw lubricating apparatus 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 in the circumferential direction. The inner diameter was made larger than the outer diameter of the ball screw. According to this lubrication device, a gap is formed between the outer diameter portion of the screw shaft and the lubricant-containing polymer member, so that the effect of retaining the lubricant can be further enhanced.

According to a third aspect of the present invention, there is provided the ball screw lubricating apparatus according to the second aspect, wherein a lubricant retaining chamfer is formed at an inner diameter side end of the divided surface of the lubricant-containing polymer member. According to this lubricating device, even if the lubricant attached to the thread groove is scraped off due to rotation of the lubricant-containing polymer member or the like, the lubricant is held by the lubricant holding chamfer and provided for lubrication.

According to a fourth aspect of the present invention, in the lubricating apparatus for a ball screw, a hermetic seal is provided on an outer portion of the lubricant-containing polymer member in the ball nut. According to this lubricating device, the hermetic seal prevents the lubricant from leaking out of the ball nut and the intrusion of foreign matter into the ball nut, and the hermetic seal is used by the lubricant that has oozed out of the lubricant-containing polymer member. Is also lubricated.

Further, if the lubricant-containing polymer member is formed so as to slide only on the outer diameter portion of the screw shaft,
There is no need 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 screw groove, in the case of molding by a mold, it is necessary to first form the 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 contraction rate of the molded product of the polymer member containing lubricant. Becomes On the other hand, in order to form the protrusion on the lubricant-containing polymer member by machining, it is necessary to make a special tool in advance according to the shape of the protrusion. Either way, the costs will increase. On the other hand, for example, if the protrusions corresponding to the screw grooves are not formed, it is not necessary to make the above-described molds and tools, and only the shaft diameter of the ball screw shaft needs to be considered, which leads to cost reduction. Become.

The lubricant-containing polymer applied to the present invention includes polyethylene, polypropylene, polybutylene,
Synthetic resins selected from the group of polyolefin resins having basically the same chemical structure, such as polymethylpentene,
Any single or mixed oil of a paraffinic hydrocarbon oil such as poly-α-olefin oil, a naphthenic hydrocarbon oil, a mineral oil, an ether oil such as a dialkyldiphenyl ether oil, an ester oil such as a phthalic acid ester, or the like as a lubricant. The raw material prepared by mixing in the form of above is plasticized by heating it above the melting point of the resin, and then cooled to make it solid.The antioxidant, rust inhibitor, and antiwear agent are added to the lubricant in advance. And various additives such as an antifoaming agent and an extreme pressure agent.

The composition ratio of the above-mentioned lubricant-containing polymer is 10 to 50% by weight of the polyolefin resin and 90 to 50% by weight of the lubricant based on the total weight. 1 polyolefin resin
If the content is less than 0% by weight, a certain level of hardness and strength 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.

The above synthetic resin groups have the same basic structure but different average molecular weights, ranging from 700 to 5 × 10 ⁶ . Waxes having an average molecular weight of 700 to 1 × 10 ⁴ (for example, polyethylene wax), those having a relatively low average molecular weight of 1 × 10 ⁴ to 1 × 10 ⁶ , and those having an average molecular weight of 1 × 10 ^{6 to} 5 An ultrahigh molecular weight of × 10 ⁶ is used alone or as a mixture as necessary.

The combination of a relatively low molecular weight lubricant with a lubricant provides a certain degree of mechanical strength, lubricant supply capacity,
A lubricant-containing polymer having oil retaining properties is obtained. If some of the relatively low molecular weight compounds are replaced with those classified as wax, the difference in molecular weight between those classified as wax and lubricating oil will increase the affinity for lubricating oil. As a result, the oil retention of the lubricant-containing polymer is improved,
The lubricant can be supplied for a long period of time. However,
On the other hand, the mechanical strength decreases. As the wax, in addition to polyolefin resins such as polyethylene wax, hydrocarbon-based waxes having a melting point in the range of 100 to 130 ° C. or more (for example, paraffin-based synthetic wax) can be used.

On the other hand, when the ultrahigh molecular weight product is replaced with a high molecular weight product, the difference in molecular weight between the ultrahigh molecular weight product and the lubricating oil is large, so that the affinity with the lubricating oil is lowered, and as a result, the oil retaining property is reduced. And the bleeding of the lubricant from the lubricant-containing polymer is accelerated. Thereby, the time required 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.

Taking into account the balance of moldability, mechanical strength, oil retention, and lubricant supply, the composition ratio of the lubricant-containing polymer is 0 to 5% by weight classified as wax and relatively low molecular weight. 8 to 48% by weight, ultra high molecular weight 2-1
0% by weight and a total of 10 to 50% by weight of the three resin components
(The balance is 90 to 50% by weight of a lubricant).

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, polyether sulfone, polyether ether ketone, polyamide imide, polystyrene, and ABS resin can be used.

On the other hand, as the thermosetting resin, resins such as unsaturated polyester resin, urea resin, melanin resin, phenol resin, polyimide resin, epoxy resin and the like can be used. These resins may be used alone or as a mixture.

Further, in order to disperse the polyolefin resin and the other resin 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 inorganic fibers such as glass fibers and metal fibers and those obtained by braiding them in the form of a cloth, or an organic compound, Carbon black, graphite powder, carbon fiber,
Aramid fiber or polyester fiber may be added.

Further, for the purpose of preventing deterioration of the polyolefin resin due to heat, N, N'-diphenyl-P-phenyldiamine, 2,2'-methylenebis (4-ethyl-
Antioxidants such as 6-t-butylphenol), and 2-hydroxy-4-n-
Octoxybenzophenone, 2- (2'-hydroxy-
An ultraviolet absorber such as 3′-t-butyl-5′-methyl-phenyl) -5-chlorobenzotriazole may be added.

The additive amount of all of the above additives (other than the polyolefin resin and the lubricant) should be 20% by weight or less of the total amount of the molding raw material as a whole of the additives, so that the lubricant supply capacity is maintained. Preferred above.

Since the above-mentioned lubricant-containing polymer is solid in itself, unlike grease or lubricating oil, water and dust do not enter into it. Therefore, when the space between the ball nut end and the screw shaft is filled with a lubricant-containing polymer, the penetration of water and dust, which cause a reduction in the life of the ball screw, in addition to or instead of the sealing member, is greatly reduced. can do.

[0032]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a ball screw lubricating apparatus according to a first embodiment of the present invention in a state in which it is mounted on 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 portion III in the configuration of FIG.

In the first embodiment shown in FIG. 1, the ball nut 2 is disposed so as to include the screw shaft 1.
A plurality of balls 3 are rotatably arranged between a screw groove 2a formed on the inner periphery of the ball nut 2 and a screw groove 1b formed on the outer periphery of the screw shaft 1 opposed thereto.

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 6a are interposed on the outer periphery of the shaft of the bolt 6, respectively. A labyrinth seal 7 is provided at the end of the seal cap 4.
Is attached to prevent foreign matter such as dust from entering from a gap between the screw shaft 1 and the seal cap 4.

The lubricant-containing polymer member 20 has a narrow groove 20a formed on the outer periphery, and the lubricant-containing polymer member 20 is placed on the outer periphery of the screw shaft 1 at a constant pressure by the garter spring 15 disposed therein. Therefore, 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 maintained and good lubrication is secured. It is supposed to be.

As shown in FIG. 2, the lubricant-containing polymer member 20 has a substantially semi-cylindrical upper half 20b and a lower half 2b.
0c. Here, the outer diameter of the screw shaft 1 is 40 mm, and the inner diameter of the upper half 20b and the lower half 20c is 40.4 m.
m. Therefore, although exaggerated in FIG. 2, only the center of the upper half 20 b and the lower half 20 c abuts on the outer periphery of the screw shaft 1, and both ends in the circumferential direction are the outer periphery of the screw shaft 1. Gaps B (four places) are formed.

Even after the garter spring 15 is attached to the outer periphery of the lubricant-containing polymer member 20, the lubricant-containing polymer member 2 can be compared with the elastic force of the garter spring 15.
0 is large and its rigidity is relatively high,
The gap B does not disappear. Furthermore, both ends in the circumferential direction of the upper half 20b and the lower half 20c are separated from each other.

On the other hand, as is apparent from FIG. 3, the inner periphery of the lubricant-containing polymer member 20 has a cylindrical shape,
Therefore, it does not have a protrusion that fits into the screw groove 1b of the screw shaft 1.

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, both circumferential ends of the upper half 26 b and the lower half 20 c of the lubricant-containing polymer member 20,
Since the gap B is formed between the outer periphery of the screw shaft 1 and the screw shaft 1 in any direction, the upper half portion 20b
At both ends of the lower half 20c, the lubricant adhering to the outer periphery of the screw shaft 1 is not scraped off (that is, no scraper action occurs), and such lubricant enters the gap B. Therefore, the lubricant adhering to the screw shaft 1 is retained, whereby lubrication between the ball and the thread groove can be ensured.

Further, since the lubricant-containing polymer member 20 does not have a protrusion fitted into the screw groove 1b of the screw thread 1, the lubricant attached to the screw groove 1b is not scraped out. The clearance B (FIG. 2) is generated by the rotation of the screw shaft 1.
The lubricant that has entered the outer periphery of the screw shaft 1
Since the upper half portion 20b and the lower half portion 20c have their central portions abutting on the outer periphery of the screw shaft 1, they lose their escape areas and flow into the screw groove 1b as shown by the arrow in FIG. Thereby, the lubrication effect can be further enhanced.

FIG. 4 is a cross-sectional view similar to FIG. 3 showing a second embodiment of the lubricant-containing polymer member. According to this embodiment, the lubricant-containing polymer member 30 has the same structure as that of the above-described embodiment. Unlike the embodiment described above, a projection 30a is provided to enter the thread groove 1b of the screw shaft 1. The projection 30a is not in contact with the inner surface of the thread groove 1b and is separated by a slight gap.

With this configuration, as in the above-described embodiment, the lubricant-containing polymer member 30 has an effect that the lubricant attached to the thread groove 1b is not scraped out. In addition, in the second embodiment, the protrusion 30
is provided, a labyrinth space is formed between the screw groove 1b and the convex portion 30a, thereby preventing foreign substances such as dust from adhering to the screw groove 1b. Can be prevented from invading.

FIG. 5 is a sectional view showing a lubricating device for a ball screw according to a third embodiment of the present invention in a state in which the lubricating device is mounted on a ball nut. In the configuration of FIG. 5, in order to further shorten the nut length, the lubricant-containing polymer member 40 is provided 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, operation and effect are the same as those of the first embodiment except that the length in the axial direction is short, and therefore, the description thereof is omitted below. Note that the bolt 6 may be directly contacted with the lubricant-containing member 40 without providing the cap 4.

FIG. 6 is a 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 a description of common parts will be omitted.

In the present embodiment, the lubricant-containing polymer member 50 is not divided into two, but is an integral member having a C-shaped cross section. However, since the both ends are separated from the outer periphery of the screw shaft 1 to form the gap B, the lubricant attached to the outer periphery of the screw shaft 1 is scraped off as in the first embodiment. There is no.

FIG. 7 is a 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 a description of common parts will be omitted.

Also in the present embodiment, the lubricant-containing polymer member 60 is not divided into two parts and is an integral member having a C-shaped cross section. A letter-shaped 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.

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. Note that the sixth embodiment will also be described with a focus on differences from the above-described embodiment, and a description of common parts will be omitted.

In this embodiment, the notch 70 formed in a part of the outer peripheral surface of the lubricant-containing polymer member 70 is used.
a has a V-shaped cross section. Therefore, in the present embodiment, the lubricant-containing polymer member 70 is more easily bent than in the above-described embodiment.

FIG. 9 is a 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 a main part showing a lower half of a lubricant-containing polymer member. Note that the seventh embodiment will also be described with a focus on differences from the above-described embodiment, and a description of common parts will be omitted.

In the present embodiment, as in the first embodiment, the lubricant-containing polymer member 20 has an upper half portion 20b and a lower half portion 20c each having a substantially semi-cylindrical shape.
A chamfer 80 for holding a lubricant is formed at each of the inner-diameter-side ends of the divided surfaces of the upper half portion 20b and the lower half portion 20c. Also, since the lubricant-containing polymer member 20 is opened in the nut outer diameter direction of the sleeve 6a, FIG.
The radial pressing of the lubricant-containing polymer member 20 toward the outer periphery of the screw shaft 1 by the garter spring 15 shown in FIG.

In the present embodiment, even if the lubricant-containing polymer member 20 swings or bends and deforms when the thread groove 1 rotates, the scraper action by the above-mentioned divided surface occurs.
The outflow of the lubricant to the skimmer A side is suppressed. For example, even if the outer peripheral surface of the screw groove 1 and the inner peripheral surface of the lower half portion 20c adhere to each other due to the swinging of the lubricant-containing polymer member 20 and the gap B disappears, as shown in FIG. The lubricant scraped out by 20c is retained as a lubricant reservoir 81 in the lubricant retaining chamfer 80, and is less likely to flow out to the skimmer A side. As a result, the lubricant hardly flows out into the space A, the lubricant is gradually supplied from the lubricant reservoir 81 to the thread groove 1b side, and good lubrication is performed over a long period of time.

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. Note that the eighth embodiment will also be described with a focus on the differences from the above-described embodiments, and a description of common parts will be omitted.

The present embodiment employs substantially the same configuration as that of the seventh embodiment, except that the lubricant-containing polymer member 2
The lubricant holding chamfers 80 formed on the upper half 20b and the lower half 20c of the "0" are so-called R chamfers.
Also in the present embodiment, even if the lubricant-containing polymer member 20 swings or bends and deforms when the screw groove 1 rotates, the scraper action by the above-described divided surface occurs, similarly to the seventh embodiment. The lubricant is prevented from flowing to the skimmer A side, and good lubrication is performed for a long period of time.

FIG. 12 is a 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 a main part showing a lower half part of the lubricant-containing polymer member. The ninth embodiment will be described with a focus on differences from the above-described embodiment, and a description of common parts will be omitted.

In this embodiment, substantially the same configuration as that of the seventh embodiment is adopted, but the chamfer 80 for holding the lubricant is formed by the inner-diameter end portions of the upper half 20b and the lower half 20c. , But not over the entire length, but with both ends in the axial direction remaining as partition walls 83.

The operation of this embodiment is almost the same as that of the seventh embodiment.
Although the lubricant is prevented from flowing out to the skimmer A side, the lubricant is also prevented from flowing out from the axial end surface. That is, as shown in FIG. 13, the lubricant scraped off by the lower half portion 20 c is retained as a lubricating oil reservoir 81 in the lubricant retaining chamfer 80, and the lower half portion 20 c Is difficult to flow out from the end face in the axial direction. As a result, the lubricant is reliably held in the lubricant holding chamfer 80, the lubricant is gradually supplied from the lubricant reservoir 81 to the thread groove 1b side, and good lubrication is performed over a long period of time.

FIG. 14 is a sectional view showing a ball screw lubricating apparatus according to a tenth embodiment of the present invention in a state in which it is mounted on a ball nut. 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 hermetically sealed seals 84 are press-fitted outside the lubricant-containing polymer members 20, respectively. The hermetic seal 84 according to the present embodiment is a known seal that is continuously in contact with the screw groove 1b of the screw shaft 1 and the outer diameter thereof. Seal tightly.

According to this lubricating device, the leakage of the lubricant to the outside of the ball nut 2 and the intrusion of foreign matter into the ball nut 2 can be further prevented on each shaft as compared with the above-described device using the labyrinth seal. The life of the screw is greatly extended.
In addition, the hermetic seal 84 is used for the lubricant-containing polymer member 20.
Since the lubricating agent is constantly lubricated, the abrasion and breakage of the lip and the like hardly occur, and extremely high durability is secured.

Although the description of the specific embodiments has been finished, the aspects of the present invention are not limited to these embodiments. For example, in each of the above embodiments,
Although the lubricant-containing polymer member is slid only on the outer diameter of the ball screw, as shown in FIG. 15, the protrusion which partially slides on the thread groove 1 b of the screw shaft 1 on the lubricant-containing polymer member 20. 85 may be formed, and in this case, substantially the same effects as those of the above embodiments can be obtained. In addition, the arrangement and fixing method of the lubricant-containing polymer member, as well as the specific structure of the ball screw and the like can be appropriately changed without departing from the spirit of the present invention.

[0061]

According to the lubricating device for a ball screw of the present invention, the outer diameter of the screw shaft is set in at least one of both ends of the ball nut and a space including a non-ball passage space inside the ball nut. Since the lubricant-containing polymer member that is in sliding contact with only the portion is attached, it is possible to prevent the lubricant attached to the thread groove from being scraped off by the lubricant-containing polymer member during the reciprocating operation of the screw shaft. The lubricant adhered to the surface can be effectively held. Also,
When the lubricant-containing polymer member slidingly contacting the outer diameter portion of the screw shaft is divided into a plurality in the circumferential direction and the inner diameter is larger than the outer diameter of the ball screw, the effect of retaining the lubricant can be further enhanced. . Further, in the lubricant-containing polymer member having the lubricant holding chamfer formed at the inner diameter side end of the divided surface, the lubricant attached to the outer periphery of the screw shaft is scraped off by rotation of the lubricant-containing polymer member or the like. Also, the lubricant is held by the lubricant holding chamfer and provided for lubrication.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a state in which a ball screw lubrication device according to a first embodiment of the present invention is mounted on a ball nut.

FIG. 2 is a view of the configuration of FIG. 1 cut along a line II-II and viewed in a direction of an arrow.

FIG. 3 is an enlarged view showing a portion III in the configuration of FIG. 1;

FIG. 4 is a cross-sectional view similar to FIG. 3, but showing a second embodiment of a lubricant-containing polymer member.

FIG. 5 is a sectional view showing a state in which a ball screw lubrication device according to a third embodiment of the present invention is mounted on a ball nut.

FIG. 6 is a 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 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 sectional view similar to FIG. 2, showing a lubricant-containing polymer member according to a seventh embodiment of the present invention.

FIG. 10 is an essential part perspective view 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 sectional view similar to FIG. 2, showing a lubricant-containing polymer member according to a ninth embodiment of the present invention.

FIG. 13 is an essential part perspective view for explaining the operation of the ninth embodiment;

FIG. 14 is a sectional view showing a state in which a ball screw lubrication device according to a tenth embodiment of the present invention is mounted on a ball nut.

FIG. 15 shows a partially modified example of a lubricant-containing polymer member.
FIG. 4 is a sectional view similar to FIG. 3.

FIG. 16 is a 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 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 ‥‥ First nut 2B ‥‥ Second nut 2C ‥‥ Preload spacer 3 ‥‥ Ball 4 ‥‥ Seal cap 6 ‥‥ Bolt 7 ‥‥ Labyrinth seal 15 ‥‥ Garter Spring 20, 30, 40, 50, 60, 70 Lubricant-containing polymer member 80 Chamfer for holding lubricant 84 Sealed seal

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Kazuo Miyaguchi 78 Tobacho, Maebashi-shi, Gunma Nippon Seiko Co., Ltd. (72) Inventor Takeshi Nakazawa 78 Toba-cho, Maebashi-shi, Gunma F-term in NSK Ltd. (reference) 3C011 FF05

Claims (4)

[Claims] 1. A ball screw lubrication device disposed between a ball nut and a screw shaft, wherein at least one of both ends of the ball nut and a space including a ball non-passing space inside the ball nut. A lubricating device for a ball screw, wherein a lubricant-containing polymer member that slides only on the outer diameter portion of the screw shaft is attached to the crab. 2. The method according to claim 1, wherein the lubricant-containing polymer member slidingly contacting the outer diameter portion of the screw shaft is divided into a plurality in the circumferential direction, and the inner diameter thereof is larger than the outer diameter of the ball screw. A lubricating device for the ball screw as described. 3. The lubricating device for a ball screw according to claim 2, wherein a chamfer for holding a lubricant is formed at an inner diameter side end of the divided surface of the lubricant-containing polymer member. 4. The ball screw lubrication according to claim 1, wherein a sealing type seal is provided on an outer portion of the lubricant-containing polymer member in the ball nut. apparatus.