JP2008002566A - Screw feeder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a screw feeder for preventing the scattering of lubricant leaking from between a screw shaft and a labyrinth seal member. <P>SOLUTION: The screw feeder comprises the labyrinth seal member 9 provided in a labyrinth seal storage recessed portion 8 formed in the end face of a nut 3, a contact seal portion forming member 10 for forming a contact seal portion on the outer periphery of the screw shaft 1 located on the end face side of the nut 3 beyond the labyrinth seal member 9, and a lubricant sucking device 14 for sucking lubricant leaking into a lubricant collecting space 11 formed between the contact seal portion forming member 10 and the labyrinth seal member 9 through a lubricant collecting hole 12 formed in the nut 3. Herein, a groove 15 such as a grinding recess is provided in the groove bottom of a spiral groove 2 formed in the outer peripheral face of the screw shaft 1 and a lubricant scraping member 20 having a protruded portion 21 at the front end in slide contact with the groove 15 is provided in the lubricant collecting space 11. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a screw feeding device such as a ball screw.

In general, a ball screw device has a screw shaft, a nut having an inner peripheral surface facing a spiral groove formed on the outer peripheral surface of the screw shaft, and a roll freely movable between the screw shaft and the spiral grooves of the nut. It is the structure provided with many balls provided.
Since the ball of such a ball screw device rolls on the groove surface of the spiral groove with the rotational movement of the screw shaft or nut, a high load is applied to the ball when using the ball screw device in an injection molding machine or the like. Since the load is applied, it is necessary to frequently supply a lubricant such as grease to prevent ball seizure. However, if a lubricant such as grease is supplied too much, the lubricant leaks from the end face of the nut. Then, the lubricant leaking from the end surface portion of the nut may be scattered around by the rotation of the screw shaft, and the surrounding environment may be contaminated by the scattered lubricant. In order to prevent such inconvenience, a ball screw device shown in FIG. 6 has been devised (see Patent Document 1).

The ball screw device shown in FIG. 6 includes a screw shaft 1, a nut 3 having a spiral groove 4 formed on the outer peripheral surface of the screw shaft 1 and facing the spiral groove 2 on the inner peripheral surface, and a spiral groove 2 of the screw shaft 1. A large number of balls 5 are provided between the nut 3 and the spiral groove 4 so as to freely roll.
The nut 3 has a flange portion 3a, and a lubricant injection port 6 is formed on the outer peripheral surface thereof. The lubricant injection port 6 communicates with a lubricant supply path 7 formed inside the flange portion 3 a, and a lubricant such as grease injected from the lubricant injection port 6 flows through the lubricant supply path 7. Then, it is supplied to the ball 5. Moreover, the nut 3 has end surface portions 3b and 3c, and circular labyrinth seal accommodating recesses 8 are formed in these end surface portions 3b and 3c.

The labyrinth seal housing recess 8 has a diameter larger than the outer diameter of the screw shaft 1 and is formed in the end surface portions 3b and 3c of the nut 3. Inside each labyrinth seal housing recess 8, a labyrinth seal member 9 and a contact seal portion are formed. Members 10 are provided opposite to each other.
The labyrinth seal member 9 is formed in an annular shape with an inner diameter slightly larger than the outer diameter of the screw shaft 1. Therefore, an annular labyrinth seal is formed between the screw shaft 1 and the labyrinth seal member 9. Yes. On the other hand, the contact seal portion forming member 10 is formed in an annular shape with an inner diameter slightly smaller than the outer diameter of the screw shaft 1, and accordingly, on the outer periphery of the screw shaft 1 positioned on the end face side of the nut 3 from the labyrinth seal member 9. The contact seal portion is formed by the contact seal portion forming member 10.

Outside the nut 3, the lubricant leaked into the lubricant recovery space 11 formed between the contact seal portion forming member 10 and the labyrinth seal member 9 and the lubricant recovery hole 12 formed in the nut 3 and the lubricant A lubricant suction device 14 that sucks through a suction pipe 13 connected to the recovery hole 12 is provided.
In such a configuration, if the supply amount of the lubricant injected from the lubricant injection port 6 is too large, excess lubricant leaks into the lubricant recovery space 11 from between the screw shaft 1 and the labyrinth seal member 9. . At this time, the lubricant leaked into the lubricant recovery space 11 is sucked out of the nut 3 by the lubricant suction device 14 through the lubricant recovery hole 12 and the suction pipe 13, so that the screw shaft 1 and the labyrinth seal member 9 It is possible to prevent the surrounding environment from being contaminated by the lubricant leaking from the space.
JP 2003-83418 A

  However, a grinding relief groove 15 as shown in FIG. 7 is often formed at the groove bottom of the spiral groove 2 formed on the outer peripheral surface of the screw shaft 1. For this reason, a part of the lubricant leaked into the lubricant recovery space 11 from between the screw shaft 1 and the labyrinth seal member 9 is accumulated in the grinding relief groove 15, and the lubricant accumulated in the grinding relief groove 15 is retained on the screw shaft 1. Since it is scattered around by rotation, it is difficult to prevent the lubricant leaked from between the screw shaft 1 and the labyrinth seal member 9 from scattering.

In addition, as a contact seal part formation member which forms a contact seal part in the outer periphery of the screw shaft 1 located in the end surface side of the nut 3 rather than the labyrinth seal member 9, the contact seal part formation member 17 as shown in FIG. When the ring-shaped contact seal portion forming member 17 having a large number of brushes 17a is used, the lubricant accumulated in the grinding clearance groove 15 can be scraped off by the brush 17a of the contact seal portion forming member 17. Since the scraped lubricant is dispersed and attached to the inner peripheral surface of the contact seal portion forming member 17, it is difficult to recover the lubricant accumulated in the grinding clearance groove 15.
The present invention has been made paying attention to the above-described problems, and an object of the present invention is to provide a screw feeding device capable of preventing the scattering of the lubricant leaked from between the screw shaft and the labyrinth seal member. It is in.

  In order to achieve the above object, the invention according to claim 1 is directed to a screw shaft, a nut having a spiral groove on the inner peripheral surface thereof opposed to the spiral groove formed on the outer peripheral surface of the screw shaft, A large number of balls provided between the spiral groove and the spiral groove of the screw shaft, and an annular labyrinth seal member provided in a labyrinth seal housing recess formed in an end surface of the nut; A contact seal portion forming member that forms a contact seal portion on the outer periphery of the screw shaft positioned on the end face side of the nut from the labyrinth seal member, and formed between the contact seal portion forming member and the labyrinth seal member. Lubricant suction means for sucking lubricant leaked from between the screw shaft and the labyrinth seal member through a lubricant recovery hole formed in the nut in a lubricant recovery space, and an outer peripheral surface of the screw shaft In the screw feeding device having a groove in the groove bottom portion of the formed spiral groove, a lubricant scraping member slidably contacting the spiral groove formed on the outer peripheral surface of the screw shaft is provided in the lubricant recovery space. And

According to a second aspect of the present invention, in the screw feeding device according to the first aspect, the lubricant scraping member has a protrusion at the tip thereof that is in sliding contact with the groove at the bottom of the spiral groove.
The invention according to claim 3 is the screw feeder according to claim 1 or 2, wherein the lubricant scraping member is provided in the lubricant recovery space so as to form an acute angle with respect to a tangential direction of the screw shaft. It is characterized by.

  According to the screw feeder according to the present invention, a part of the lubricant leaked into the lubricant recovery space from between the screw shaft and the labyrinth seal member does not collect in the groove such as the grinding relief, and the groove such as the grinding relief Since the lubricant accumulated in the cylinder hardly scatters around due to the rotation of the screw shaft, it is possible to prevent the lubricant leaked from between the screw shaft and the labyrinth seal member.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
A schematic configuration of a screw feeder according to a first embodiment of the present invention is shown in FIG. The screw feeding device shown in FIG. 1 includes a screw shaft 1, a nut 3 having a spiral groove 4 formed on the outer peripheral surface of the screw shaft 1 and facing the spiral groove 2 on the inner peripheral surface, and a spiral groove of the screw shaft 1. 2 and a spiral groove 4 of the nut 3, and a large number of balls 5 provided so as to roll freely. Grinding clearance grooves 15 and 16 are formed at the groove bottoms of the spiral grooves 2 and 4. Yes.

  The nut 3 has a flange portion 3a, and a lubricant injection port 6 is formed on the outer peripheral surface thereof. The lubricant injection port 6 communicates with a lubricant supply path 7 formed inside the flange portion 3 a, and a lubricant such as grease injected from the lubricant injection port 6 flows through the lubricant supply path 7. Then, it is supplied to the ball 5. Moreover, the nut 3 has end surface portions 3b and 3c, and circular labyrinth seal accommodating recesses 8 are formed in these end surface portions 3b and 3c.

The labyrinth seal housing recess 8 has a diameter larger than the outer diameter of the screw shaft 1 and is formed in the end surface portions 3b and 3c of the nut 3. Inside each labyrinth seal housing recess 8, a labyrinth seal member 9 and a contact seal portion are formed. Members 10 are provided opposite to each other.
The labyrinth seal member 9 is formed in an annular shape with an inner diameter slightly larger than the outer diameter of the screw shaft 1. Therefore, an annular labyrinth seal is formed between the screw shaft 1 and the labyrinth seal member 9. Yes. On the other hand, the contact seal portion forming member 10 is formed in a substantially annular shape with an inner diameter slightly smaller than the outer diameter of the screw shaft 1, and accordingly, the outer periphery of the screw shaft 1 positioned on the end face side of the nut 3 from the labyrinth seal member 9. The contact seal portion is formed by the contact seal portion forming member 10.

Outside the nut 3, the lubricant leaked into the lubricant recovery space 11 formed between the contact seal portion forming member 10 and the labyrinth seal member 9 and the lubricant recovery hole 12 formed in the nut 3 and the lubricant A lubricant suction device (not shown) for suctioning through a suction pipe 13 connected to the recovery hole 12 is provided.
A lubricant scraping member 20 is provided in the lubricant recovery space 11. These lubricant scraping members 20 are provided in the lubricant recovery space 11 so as to form an acute angle with respect to the tangential direction of the screw shaft 1, and projecting portions 21 (see FIG. 1) that are in sliding contact with the grinding clearance grooves 15 are provided at the tips. Have. Further, as shown in FIG. 3, the lubricant scraping member 20 includes a large number of lubricant scraping brushes 22 and a brush bundling member 23 that binds the base end portions of the lubricant scraping brushes 22 into one. Thus, the lubricant scraping brush 22 is bundled by the brush bundling member 23 so as to be wider than the width a of the lubricant collection space 11. In FIG. 2, reference numeral 24 denotes the lubricant accumulated in the grinding clearance groove 15.

  In such a configuration, the lubricant leaked into the lubricant recovery space 11 from between the screw shaft 1 and the labyrinth seal member 9 is connected to the lubricant recovery hole 12 and the lubricant recovery hole 12 formed in the nut 3. Then, it is sucked out of the nut 3 by the lubricant suction device through the suction pipe 13. At this time, as shown in FIG. 2, the lubricant 24 accumulated in the grinding relief groove 15 is scraped off by the protrusion 21 of the lubricant scraping member 20 and then sucked outside the nut 3 by the lubricant suction device. Is done. As a result, as in the conventional example described above, a part of the lubricant leaked into the lubricant recovery space 11 from between the screw shaft 1 and the labyrinth seal member 9 does not collect in the grinding relief groove 15, and the grinding relief groove Since the lubricant accumulated in 15 hardly scatters around due to the rotation of the screw shaft 1, the lubricant leaked from between the screw shaft 1 and the labyrinth seal member 9 can be reliably prevented.

  The lubricant collected in the vicinity of the lubricant recovery hole 12 may be dropped freely if it is oil, and may be recovered by providing a lubricant receiver (not shown) under the screw shaft 1. A pipe may be provided and sent to a lubricant recovery tank (not shown). If the lubricant is difficult to flow, such as grease, it may be sucked from the lubricant recovery hole 12 or may be recovered from the lubricant recovery hole 12 by injecting compressed air into the lubricant recovery space 11. good. Further, the recovered lubricant may be supplied again into the nut.

  In the above-described first embodiment, a large number of lubricant scraping brushes 22 and the lubricant scraping brushes are used as a lubricant scraping member for scraping off the lubricant accumulated in the grinding clearance grooves 15 in the lubricant recovery space 11. The brush bundling member 23 for bundling the base end portion of the take-up brush 22 into one is illustrated, but as shown in FIG. 4, a lubricant scraping portion 25 made of a soft material such as sponge or felt, and this The same effect as that of the first embodiment can be obtained even if a member composed of two fixing plates 26 for fixing the lubricant scraping portion 25 in the lubricant recovery space is used.

FIG. 5 is a diagram showing a second embodiment of the present invention. The second embodiment is different from the first embodiment in that a gap 27 is provided on the rear side of the lubricant scraping member 20. is there. According to such a configuration, the lubricant accumulated on the rear side of the lubricant scraping member 20 can be quickly discharged from the lubricant recovery hole 12 to the outside of the nut 3.
Although the case where the present invention is applied to a ball screw is shown in the first and second embodiments described above, the present invention can be applied to all screw feeding devices such as a roller screw, a planetary roller screw, and a slide screw.

It is sectional drawing which shows schematic structure of the screw feeder which concerns on the 1st Embodiment of this invention. It is sectional drawing which follows the II-II line of FIG. It is a figure which shows an example of the lubricant scraping member shown in FIG.1 and FIG.2. It is a figure which shows the other example of a lubricant scraping member. It is a figure which shows the 2nd Embodiment of this invention. It is sectional drawing which shows the conventional ball screw apparatus provided with the labyrinth seal member and the contact seal part formation member. It is sectional drawing which shows the grinding clearance groove formed in the groove bottom part of the spiral groove. It is a figure which shows the prior art example of a contact seal part formation member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Screw shaft 2,4 Spiral groove 3 Nut 5 Ball 8 Labyrinth seal accommodation recessed part 9 Labyrinth seal member 10 Contact seal part formation member 11 Lubricant collection space 12 Lubricant collection hole 13 Suction pipe 14 Lubricant suction device 15, 16 Grinding escape Groove 20 Lubricant scraping member 21 Projection

Claims (3)

A screw shaft, a nut having a spiral groove on the inner peripheral surface facing the spiral groove formed on the outer peripheral surface of the screw shaft, and an annular ring provided in a labyrinth seal housing recess formed on an end surface portion of the nut A labyrinth seal member, a contact seal portion forming member that forms a contact seal portion on an outer periphery of a screw shaft positioned on the end face side of the nut from the labyrinth seal member, and the contact seal portion forming member and the labyrinth seal member A lubricant suction means for sucking a lubricant leaked from between the screw shaft and the labyrinth seal member through a lubricant recovery hole formed in the nut in a lubricant recovery space formed therebetween; In the screw feeder having a groove at the groove bottom of the spiral groove formed on the outer peripheral surface of the shaft,
A screw feeding device, wherein a lubricant scraping member slidably contacting a spiral groove formed on an outer peripheral surface of the screw shaft is provided in the lubricant recovery space.   2. The screw feeding device according to claim 1, wherein the lubricant scraping member has a protrusion at a tip thereof that is in sliding contact with the groove at the bottom of the spiral groove.   3. The screw feeding device according to claim 1, wherein the lubricant scraping member is provided in the lubricant recovery space so as to form an acute angle with respect to a tangential direction of the screw shaft.

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