JPH1177476A - Labyrinth seal device for machine tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seal structure capable of installing the device easily and with good accuracy even in a space whose circumference is narrow while preventing cutting oil agent from invading into a bearing part for journalling a rotary shaft. SOLUTION: A labyrinth seal device 30 of a machine tool which is arranged between a machine frame 3 of the machine tool and a screw shaft 5 of a ball screw 2 and is arranged in order to seal a bearing part 4 for rotatably journalling the screw shaft 5, is provided with a fixing side labyrinth seal member 31 arranged on the machine frame 3 side; a rotary side labyrinth seal member 32 which is movably arranged in an axial C direction of the screw shaft 5, whose inner circumferential part is provided with an annular inner circumferential engaging groove 38, and which a clearance part provided with prescribed clearances (a), (b) is formed between the fixing side labyrinth seal member and the rotary side labyrinth seal member 32; and an elastic fixing member 33 for fixing the rotary side labyrinth seal member 32 to the screw shaft 5 by engaging with the annular outer peripheral engaging groove 39 formed on an outer peripheral part 36 of the screw shaft 5 and the inner circumferential engaging groove 38 of the rotary side labyrinth seal member in an elastically deformed condition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotating shaft of a machine tool such as a machining center (hereinafter, referred to as MC), an NC (numerical control) lathe, etc. The present invention relates to a labyrinth seal device for preventing chips, dust and the like from entering.

[0002]

2. Description of the Related Art A feed screw such as a ball screw used in a machine tool moves a moving body such as a feed table or a table in a feed direction with high precision and smoothness. The lubrication system for the bearing portion that supports the screw shaft (rotary shaft) of the feed screw includes a forced lubrication system in which lubricating oil is forcibly supplied at predetermined time intervals, and a grease lubricated by grease sealed in advance. There is a lubrication system. Of these two systems, the grease lubrication system is easier to maintain because there is no need to collect the lubricating oil, and there is less risk of environmental pollution due to the inability to completely recover.

[0003] In a machine tool, a feed screw, a bearing, and the like are covered and protected by a slide cover or the like, but a part of a cutting oil, a chip, dust, and the like are surrounded around a bearing of the feed screw. It scatters like a mist.
Therefore, it is necessary to provide a sealing measure for the bearing portion so that cutting oil or the like does not enter the inside of the bearing portion. Therefore, conventionally, in many cases, sealing is performed by a packing member such as an oil seal or a dust seal in which the lip portion contacts the screw shaft of the feed screw. Particularly, in a bearing portion of a feed screw of a machine tool, since it is required to provide a seal portion in a narrow space, a contact-type packing member is often used.

[0004]

In recent machine tools,
As the feed speed of the moving body is increasing, the rotation speed of the feed screw is also increasing. Therefore, as described above,
When a contact-type packing member is used for the seal portion, heat is generated at the contact portion with the packing member, and the feed screw is thermally deformed, thereby causing a problem that processing accuracy may be reduced.

On the other hand, in a machine tool, a labyrinth seal is provided to protect a bearing for supporting a main shaft, but a labyrinth seal is formed in a narrow space near a bearing in a bearing of a feed screw. Must. In particular, it is not easy to attach the rotation side labyrinth seal member to the screw shaft of the feed screw, and there is a problem that the labyrinth seal device cannot be downsized.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and it is possible to prevent cutting oil or the like from entering a bearing portion that supports a rotating shaft, and to easily and accurately obtain a small space even in a narrow space. An object of the present invention is to provide a labyrinth seal device for a machine tool that can be mounted well.

[0007]

In order to achieve the above-mentioned object, a labyrinth seal device according to the present invention is provided between a machine tool body and a rotating shaft, and rotatably supports the rotating shaft. A labyrinth seal device for a machine tool for sealing a bearing portion, comprising: a fixed labyrinth seal member provided on the machine body side; a movable labyrinth seal member provided on the machine body side; And a rotating labyrinth seal member capable of forming a gap having a predetermined gap between the rotating labyrinth seal member and the fixed side labyrinth seal member. By elastically engaging both the annular outer circumferential engaging groove and the inner circumferential engaging groove of the rotating side labyrinth seal member in an elastically deformed state, the elastic solid fixing the rotating side labyrinth seal member to the rotating shaft. And a member.

In the labyrinth seal device, the elastic fixing member engages with the outer peripheral engaging groove formed on the rotating shaft and the inner peripheral engaging groove formed on the rotating labyrinth seal member, and When the rotation-side labyrinth seal member is fixed to the shaft, it is preferable that the fixed-side labyrinth seal member and the rotation-side labyrinth seal member form the gap having the predetermined gap.

It is preferable that the rotation shaft is a screw shaft of a feed screw for moving a moving body with respect to the body, and the elastic fixing member is an O-ring.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a front sectional view of a labyrinth seal device on a rotating shaft of a machine tool according to an embodiment of the present invention. In this embodiment, a description will be given of a labyrinth seal device that protects a bearing that rotatably supports a screw shaft (rotary shaft) of a feed screw of a machine tool, but a labyrinth seal for a bearing of another rotary shaft. It may be a device.

As shown in FIG. 1, a feed screw 2 of a machine tool 1 has a screw shaft 5 serving as a rotating shaft rotatably supported by a bearing 4 attached to a body 3 of the machine tool 1. A moving body (not shown) is reciprocated by being guided by a guide portion provided on the body 3 in the direction of the axis C. When the machine tool 1 is, for example, an MC (machining center), the moving body includes a table, a column, a spindle head, and the like. When the lathe is used, the moving body includes a saddle, a cross slide, and the like.
There are turrets and tailstocks. For example, in the case of MC, a bed when the moving body is a table, a column when the moving body is a spindle head, and the like correspond to the machine body 3 that supports the moving body relatively movably. It should be noted that other types of machine tools, such as a grinding machine and a turning center, may be used as long as the machine tool has the feed screw 2 provided with the rotating shaft.

A ball screw is often used for the feed screw 2. In the ball screw 2, a ball nut 6 fixed to the moving body side is screwed into a screw shaft 5 rotatably supported on the machine body 3 side. A servomotor 7 is attached to an end of the body 3, and an output shaft 8 of the servomotor 7 is connected to one end 10 of the screw shaft 5 via a coupling 9. When the ball screw 2 is driven to rotate in the forward and reverse directions by the servomotor 7, the moving body reciprocates in the direction of the axis C together with the ball nut 6 screwed into the screw shaft 5.

A bearing support 11 which forms a part of the body 3 and corresponds to a housing of the bearing portion 4 is fixed to the body 3 integrally or separately, and in the present embodiment, it is formed integrally. Is shown. In the bearing part 4, the bearing support 1
One or a plurality of (here, three) bearings 16 are housed in the housing portion 15 formed in one. The bearing 16 is of a grease lubrication system in which the bearing 16 is lubricated with grease sealed in advance.

The outer ring of the combined bearing 16 is
The retainer 17 attached to the bearing support 11 pushes into the storage portion 15 and is positioned and fixed. On both sides of the inner ring of the combined bearing 16, annular collars 18, 22 are provided, respectively. One collar 18 is held down by a nut 19 and the other collar 2
2 is positioned between the bearing 16 and the step 23 of the ball screw 2 to position the inner ring of the bearing 16. That is, by fixing the inner and outer races of the bearing 16 in this manner, a predetermined preload is given to the combined bearing 16. A cover 21 attached to the retainer 17 covers the periphery of the nut 19.

At one opening (left side in FIG. 1) of the bearing portion 4, one end 10 of the rotating screw shaft 5 and a collar 18 are provided.
And the cover 21 and the retainer 17 on the fixed (non-rotating) side.
Are in a non-contact state via a minute gap. Therefore, the gap having the minute gap serves as a labyrinth seal to prevent cutting oil or the like from entering the bearing 16 from outside the bearing 4. In this manner, one opening of the bearing portion 4 is covered and sealed.

The other opening (right side in FIG. 1) of the bearing portion 4 is sealed in a non-contact state by a labyrinth seal device 30 provided between the body 3 and the screw shaft 5. The labyrinth seal device 30 includes an annular fixed-side labyrinth seal member (hereinafter, referred to as a fixed-side seal member) 31 attached to the body 3 (that is, the bearing support 11) and having an inner peripheral hole 35, and a rotating side. Annular labyrinth seal member attached to the shaft (hereinafter referred to as the rotational seal member)
32 and an O-ring 33 as an annular elastic fixing member. The elastic fixing member includes a ring packing called an X ring, a D ring, a T ring, or the like,
A lip-shaped packing called a U-packing or a V-packing may be used.

The fixed-side seal member 31 is separate from the bearing support 11 and is press-fitted and fixed in a through hole 34 formed in the bearing support 11, but is formed integrally with the bearing support 11. May be. The labyrinth seal device 30
Has shown the case where the other opening of the bearing portion 4 is sealed. However, even when the labyrinth seal device 30 seals one or both of the one opening and the other opening of the bearing portion 4. Good.

The fixed-side seal member 31 covers the opening of the bearing portion 4, and has an inner peripheral hole 35 of the fixed-side seal member 31,
There is a small gap between the screw shaft 5 and the outer periphery of the shaft portion 24. The rotation side seal member 32 is attached to the outer peripheral portion 36 of the screw shaft 5 so as to be movable in the direction of the axis C of the ball screw 2. An annular inner circumferential engagement groove 38 is formed in the inner circumferential portion 37 of the rotation side seal member 32. The rotating side seal member 32 is formed in a shape (for example, a substantially L-shaped cross section in the axial direction) that maintains a gap having at least a predetermined minute gap with at least the fixed side seal member 31.

The O-ring 33 is engaged with both the annular outer peripheral engaging groove 39 formed on the outer peripheral portion 36 of the screw shaft 5 and the inner peripheral engaging groove 38 of the rotating side seal member 32 in an elastically deformed state. I agree. As a result, the O-ring 33 positions and holds the rotation-side seal member 32 at a predetermined position on the screw shaft 5 and fixes the rotation-side seal member 32 to a small gap between the rotation-side seal member 32 and the fixed-side seal member 31. To rotate integrally with the screw shaft 5. That is, the gap a in the axial direction and the gap b in the inner and outer radial directions between the rotary side seal member 32 and the fixed side seal member 31 have predetermined dimensions (for example, about 0.2 to about 0.5 mm). The rotation side seal member 32 is fixed. The O-ring 33 also prevents cutting oil or the like from entering the bearing 4 from outside the bearing 4 through a gap between the screw shaft 5 and the rotation-side seal member 32. . The ball screw 2, the bearing 4, the coupling 9, and the like are covered by a slide cover (not shown).

FIG. 2 is an enlarged sectional view showing a state in which the labyrinth seal device 30 is incorporated. As shown in FIG.
The inner peripheral portion 37 of the rotary seal member 32 fitted on the screw shaft 5 of the ball screw 2 is fitted on the outer peripheral portion 36 of the screw shaft 5. The inner peripheral portion 37 in which the inner peripheral engagement groove 38 is formed is formed on one side (the right side in FIG. 2) with respect to the inner peripheral engagement groove 38. An insertion hole 40 is formed on the other side (left side in FIG. 2) with respect to the inner peripheral engagement groove 38. Insertion hole 40
When the rotary seal member 32 is moved in the direction of the axis C and assembled, the inner diameter of the O-ring 33 is elastically deformed and can be inserted into the inner circumferential engagement groove 38 of the rotary seal member 32. On the outer side (left side in FIG. 2) of the insertion hole 40,
An inclined guide hole 44 inclined outward is formed.

Accordingly, when the rotary side seal member 32 is assembled, the O-ring 33 is squashed while the inclined guide hole 44 and the insertion hole 40 are arranged in this order.
2 is movable, and engages with the inner circumferential engagement groove 38 in an elastically deformed state so that the screw shaft 5 and the rotation side seal member 32 can be fixed by the elastic force. The entirety of the inclined guide hole 44, the insertion hole 40, and the inner peripheral engagement groove 38 may be formed as a continuous curved surface. The O-ring 33 engages with both the outer peripheral engaging groove 39 formed on the outer peripheral portion 36 of the screw shaft 5 to engage the O-ring 33 and the inner peripheral engaging groove 38 of the rotating side seal member 32. The rotation side seal member 32 is fixed to the screw shaft 5 by an elastic force.

Next, a procedure for incorporating the labyrinth seal device 30 will be described. First, the rotation-side sealing member 32 is inserted into the screw shaft 5 of the ball screw 2, and the O-ring 33 is attached to the outer peripheral engagement groove 39 of the screw shaft 5. On the other hand, the fixed-side sealing member 31 is fixed to the bearing support 11 by driving or fastening with a bolt or the like. Next, after inserting the screw shaft 5 of the ball screw 2 into the bearing support 11, the collar 22, the bearing 16, the retainer 17, the collar 18,
The ball screw 2 is mounted on the bearing support 11 by sequentially incorporating the nut 19 and the cover 21.

Next, the rotation side seal member 32 is moved in the direction of the axis C to approach the fixed side seal member 31 and the O-ring 33 engaged in the outer circumferential engagement groove 39 of the screw shaft 5 is rotated. 32 is engaged with the inner peripheral engagement groove 38. At this time, since the insertion hole 40 is formed in the rotation-side seal member 32, the O-ring 33 is engaged with the inner peripheral engagement groove 38 while being crushed and elastically deformed.

As a result, the rotation-side seal member 32 is connected to the screw shaft 5 via the O-ring 33 engaged with the outer peripheral engaging groove 39 and the inner peripheral engaging groove 38 while being elastically deformed so as to exert an elastic force. At a predetermined position. As a result, the rotating side sealing member 32 and the fixed side sealing member 31 are secured in a non-contact state with a gap having a minute gap having a predetermined dimension a in the axial direction. Between the inner diameter portion 32a of the rotating side seal member 32 and the outer diameter portion 31a of the fixed side seal member 31, a gap portion having a minute gap of a predetermined size b is secured, and a non-contact state is established.

The inner peripheral hole 35 of the fixed side seal member 31
A small gap is secured between the screw shaft 5 and the outer peripheral portion 45 of the screw shaft 5. Further, the outer peripheral surface 45 of the collar 22 that rotates together with the screw shaft 5 of the ball screw 2, and the through hole 34 of the bearing support 11.
A small gap is also secured between them. As a result, from the outside of the labyrinth seal device 30 to the bearing 16, a labyrinth seal having a meandering complicated and long passage between the rotating portion and the fixed portion is formed, and good sealing performance is obtained. Demonstrate. Similarly, one side of the bearing 16 is connected to the inner peripheral portion of the cover 21 and the screw shaft 5.
The labyrinth seal device is constituted by the outer peripheral portion of the retainer 17, the inner peripheral portion of the retainer 17, and the outer peripheral portion of the collar 18.

Next, the operation will be described. When the servo motor 7 is driven to move the moving body to a predetermined position, the ball screw 2 is driven via the output shaft 8 and the coupling 9.
Is driven to rotate, and the movable body moves integrally with the ball nut 6 to a predetermined position in the direction of the axis C. When the screw shaft 5 rotates, the rotation side seal member 3
2 and the collar 22 attached to the screw shaft 5
And rotate together. These rotating parts rotate in a non-contact state with respect to the fixed parts such as the fixed-side seal member 31 and the bearing support 11 via a minute gap.

In the prior art in which the sealing was performed using the contact-type packing member as described above, heat was generated in the seal portion. However, in the present invention, the non-contact type labyrinth sealing device 30 was used.
Is used, even if the screw shaft 5 of the ball screw 2 rotates at a high speed, no heat is generated in the seal portion, and the ball screw 2 does not undergo thermal displacement, thereby improving processing accuracy.

Since the labyrinth seal device 30 has good sealing performance, during the rotation of the screw shaft 5 of the ball screw 2, the cutting oil or the like is blown off by the centrifugal force of the rotating side seal member 32 and the like, and the inside of the bearing portion 4 Do not invade. When the screw shaft 5 of the ball screw 2 is not rotating, it falls from below the gap between the inner peripheral side of the rotary seal member 32 and the outer peripheral side of the fixed seal member 31. The cutting oil accumulated in the inner peripheral groove 31b of the fixed-side seal member 31 and the inner peripheral portion 21b of the cover 21 is removed by through holes 31c and 2 formed respectively below.
It falls from 1a. Therefore, the cutting oil etc.
And the bearing 16 is protected.

In the labyrinth seal device 30 of the present invention, the O-ring 33 is engaged with the outer peripheral engagement groove 39 formed in the screw shaft 5 and the inner peripheral engagement groove 38 formed in the rotary side seal member 32. When the rotation side seal member 32 is fixed to the shaft 5,
A gap having predetermined gaps a and b is formed between the fixed-side seal member 31 and the rotation-side seal member 32. Therefore, the rotary side seal member 32 is incorporated into the predetermined position with high precision without adjusting the position of the rotary side seal member 32 while measuring the dimensions of the gaps a and b. The small gaps a and b between the first and second fins 31 can be secured with high accuracy. This assembly work only needs to move the rotary side seal member 32 in the direction of the axis C by pushing, so that the work can be easily performed even if the space is narrow.

Since the labyrinth seal device 30 itself can be formed compactly, it can be easily incorporated even in a narrow space. Also, on the screw shaft 5 side,
It is not necessary to form an end portion for bringing the labyrinth seal device 30 into contact, a screw portion for fixing, and the like. Since the rotating side sealing member 32 of the labyrinth sealing device 30 has a small mass, it hardly affects the rotating operation of the ball screw 2 rotating at high speed. Since the bearing portion 4 is grease-lubricated, there is no need to collect lubricating oil, so that maintenance is easy, and there is little chance that the oil will leak to the outside during collection and pollute the environment.

In the present embodiment, the rotating side seal member 32,
Although the inner and outer diameter portions of the fixed side seal member 31 are formed in a cylindrical shape to form the gap, the gap may be formed in another shape as shown in FIGS. FIG. 3 is an enlarged sectional view of a labyrinth seal device 30a according to another embodiment, and FIG. 4 is an enlarged sectional view of a labyrinth seal device 30b according to still another embodiment. Note that the same or corresponding parts as those of the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In the labyrinth seal device 30a shown in FIG. 3, one or a plurality of grooves 51 having a triangular (or square) cross section are formed between the rotary seal member 32 and the fixed seal member 31. One or both of the inner and outer diameter portions and the opposing side portions of the rotating side seal member 32 and the fixed side seal member 31 are formed in a predetermined shape so as to be formed in the gap. On the other hand, the labyrinth seal device 30b shown in FIG.
Then, one or a plurality of grooves 51 having a triangular (or square) cross-sectional shape and a meandering passage 52 are formed in a gap between the rotation-side seal member 32 and the fixed-side seal member 31. As described above, one or both of the inner and outer diameter portions and the opposing side surface portions of the rotating side seal member 32 and the fixed side seal member 31 are formed in a predetermined shape.

The labyrinth seal device 3 having such a configuration
0a, 30b, the labyrinth seal device 30a,
From the outside of 30b to the bearing 16, a labyrinth seal having one or more small chambers composed of the groove 51 and a complicated passage composed of the meandering passage 52 is formed between the rotating part and the fixed part. Therefore, a better sealing performance is exhibited. The same reference numerals in the drawings indicate the same or corresponding parts.

[0034]

Since the labyrinth seal device according to the present invention is constructed as described above, it is possible to prevent cutting oil or the like from entering the seal portion of the bearing portion that supports the rotating shaft, to prevent heat generation, and to prevent heat generation. However, it can be easily installed even in a narrow space.

[Brief description of the drawings]

FIG. 1 is a front sectional view showing an example of an embodiment of a labyrinth seal device according to the present invention.

FIG. 2 is an enlarged sectional view showing a state in which the labyrinth seal device is incorporated.

FIG. 3 is an enlarged cross-sectional view of a labyrinth seal device according to another embodiment.

FIG. 4 is an enlarged sectional view of a labyrinth seal device according to still another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Machine tool 2 Ball screw (feed screw) 3 Body 4 Bearing part 5 Screw shaft (rotating shaft) 11 Bearing support (body) 30, 30a, 30b Labyrinth seal device 31 Fixed labyrinth seal member 32 Rotational labyrinth seal member 33 O-ring (elastic fixing member) 36 Outer peripheral portion of screw shaft (outer peripheral portion of rotating shaft) 37 Inner peripheral portion of rotation-side labyrinth seal member 38 Inner peripheral engaging groove 39 Outer peripheral engaging groove a, b Gap C axis

Claims (4)

[Claims] 1. A labyrinth seal device for a machine tool, which is provided between a machine body of a machine tool and a rotating shaft and seals a bearing portion rotatably supporting the rotating shaft. Between the fixed labyrinth seal member provided, and an annular inner circumferential engagement groove formed in the inner peripheral portion so as to be movable in the axial direction of the rotating shaft, and between the fixed labyrinth seal member. A rotating labyrinth seal member capable of forming a gap portion having a predetermined gap, an annular outer circumferential engaging groove formed on an outer circumferential portion of the rotating shaft, and the inner circumferential engaging groove of the rotating labyrinth seal member. And a resilient fixing member for fixing the rotating side labyrinth seal member to the rotating shaft by being engaged with both of them in an elastically deformed state. 2. The elastic fixing member is engaged with the outer peripheral engaging groove formed on the rotating shaft and the inner peripheral engaging groove formed on the rotating labyrinth seal member, and the rotating shaft is rotated on the rotating shaft. 2. The fixed labyrinth seal member and the rotating labyrinth seal member forming the gap having the predetermined gap when the side labyrinth seal member is fixed. 3. Labyrinth sealing equipment for machine tools. 3. The labyrinth seal device for a machine tool according to claim 1, wherein the rotation shaft is a screw shaft of a feed screw for moving a moving body with respect to the machine body. 4. The labyrinth seal device for a machine tool according to claim 1, wherein the elastic fixing member is an O-ring.