JP4795816B2 - Rotary shaft seal mechanism - Google Patents

Description

  The present invention relates to a seal mechanism in a rotary shaft provided in, for example, a rotatable table or a main shaft.

  For example, a cutting fluid is used when cutting a workpiece, so that a cutting fluid containing chips or the like does not enter the housing that supports the rotating shaft. It is necessary to provide a sealing mechanism. As such a sealing mechanism, a contact-type sealing mechanism having a sealing member that physically seals between the rotating shaft and the housing, a labyrinth mechanism that is a non-contact sealing mechanism with respect to the rotating shaft, and the like have been conventionally used. More known.

The contact-type seal mechanism can exert a reliable sealing performance when the rotating shaft rotates only at a relatively low speed. Since durability cannot be maintained, it cannot be applied to a rotating shaft that rotates at high speed.
On the other hand, the labyrinth mechanism provides a complex labyrinth between the rotating shaft and the housing, prevents cutting fluid from reaching the inside of the housing, and provides a discharge port at an appropriate position of the labyrinth to enter the labyrinth. It is intended to discharge the infiltrated cutting fluid using gravity or centrifugal force of the rotating shaft. Since such a labyrinth mechanism does not have a seal member or the like that contacts the rotating shaft, it can be suitably used for a rotating shaft that rotates at a high speed, but the rotating shaft continues to rotate at a low speed. Then, a centrifugal force sufficient to discharge the cutting fluid that has entered the labyrinth cannot be obtained, and as a result, the cutting fluid may be allowed to enter the housing.

  For this reason, a seal mechanism as described in Patent Document 1 has been devised to enable reliable sealing that is not affected by the rotational speed of the rotating shaft.

JP-A-2005-59151

Here, the sealing mechanism described in Patent Document 1 will be described with reference to FIG. FIG. 2 is an explanatory cross-sectional view showing the sealing mechanism described in Patent Document 1. As shown in FIG.
Reference numeral 31 denotes a housing that rotatably supports the rotation shaft 32, and a blade 34 is rotatably attached to the front end portion of the rotation shaft 32 together with the rotation shaft 32 via a flange 33. A labyrinth 35 which is a non-contact type sealing mechanism is provided between the housing 31 and the rotating shaft 32, and air can be supplied into the labyrinth 35 from the housing 31 side. On the other hand, a V-ring (V-type end face seal) 36 that is a contact-type seal member is installed on the flange 33 that rotates together with the rotary shaft 32, and its lip portion 37 comes into contact with the front end face of the housing 31 to form a labyrinth. The upper part of the opening 35 is covered.

  In the sealing mechanism as described above, when the rotary shaft 32 rotates at a low speed, the lip portion 37 of the V ring 36 prevents the cutting fluid from entering the housing 31. Further, when the rotating shaft 32 rotates at a high speed, by supplying air into the labyrinth 35, the air is ejected from the opening of the labyrinth 35, and the lip portion 37 is pushed up to be in a non-contact state with respect to the housing 31. At the same time, the injecting air prevents cutting fluid and the like from entering the labyrinth 35. Then, when shifting from high speed rotation to low speed rotation (or rotation stop), the air supply into the labyrinth 35 is stopped, and the lip portion 37 naturally moves to the seal position that covers the upper part of the opening of the labyrinth 35 by the elastic force. I am trying to return.

However, in the sealing mechanism described in Patent Document 1, since the lip portion 37 relies on the elastic force or the like to return the lip portion 37 to the sealing position when moving from high speed rotation to low speed rotation, the lip portion 37 is It takes time to return to the sealing position (that is, sealing is performed by the V ring 36). Therefore, the cutting fluid may enter the housing 31 during the transition from the seal by air to the seal by the V ring 36. Particularly, in the case of the main shaft (rotary shaft) of the cutting apparatus as described in Patent Document 1, the lip portion 37 of the V-ring 36 tends to float due to centrifugal force because it is a fairly high speed even if it is low-speed rotation ( It tends to be separated from the front end surface of the housing 31), resulting in a problem that the sealing performance becomes poor.
Moreover, even if the sealing is performed with air until the rotational speed reaches a level at which the lip portion 37 can be surely restored, reliable sealing performance cannot be expected only with the ejection of air. Furthermore, even if a discharge port is provided in the labyrinth, a centrifugal force sufficient to discharge the cutting fluid to the outside cannot be obtained at low speed rotation, so that the penetration of the cutting fluid into the housing 31 cannot be prevented. .

  Therefore, the present invention has been made in view of the above-described problems, and an object of the present invention is to provide a rotary shaft sealing mechanism capable of exhibiting reliable sealing performance regardless of the rotational speed of the rotary shaft.

To achieve the above object, the invention according to claim 1 of the present invention includes a rotating shaft rotational speed I by the rotatable control device in the longitudinal direction as an axis is controlled, of the rotary shaft A rotating shaft that is provided between a housing that rotatably supports the front side protruding forward, and that seals between the housing and the rotating shaft in order to prevent cutting fluid from entering the housing. A first air supply path for supplying air between the protruding portion of the rotating shaft and the front surface of the housing, and a protrusion of the housing or the rotating shaft. A seal member that closes / opens the space between the housing and the rotation shaft on the outer peripheral side of the opening of the first air supply path by contact / non-contact; A second air supply path for discharging air to the seal member is opened on the outer peripheral side of the member, while the control device switches the air between the first air supply path and the second air supply path. When the rotating shaft stops or rotates at a low speed, the control device supplies air via the second air supply path and discharges the air to the seal member, so that the seal When a member is pressed against the rotating shaft or the housing to seal between the housing and the rotating shaft, when the rotating shaft rotates at high speed, air is supplied and discharged through the first air supply path. The seal member is pushed up so as not to be in contact with the rotary shaft or the housing, and the space between the housing and the rotary shaft is sealed by the discharged air. That.
According to a second aspect of the present invention, in the first aspect of the invention, a concave groove is formed in the front surface of the housing, a first air supply path is opened in the concave groove, and a discharge path communicating with the outside of the housing is provided. On the other hand, a cylindrical portion that fits into the groove is provided on the projecting portion of the rotating shaft, and a slinger is provided on the cylindrical portion, and the cutting fluid that has entered the groove is rotated by the rotating shaft. Thus, it is possible to discharge to the outside of the housing through the discharge path.
According to a third aspect of the present invention, in the first or second aspect of the present invention, a flange having a diameter larger than the opening position of the second air supply path provided on the front surface of the housing is provided on the projecting portion of the rotating shaft, and the flange The rotating shaft is supported by the housing so that the front surface of the opening of the second air supply path is covered with the air, and the space between the housing and the flange of the rotating shaft is discharged by the air discharged through the second air supply path. It is possible to seal.
The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the seal member is a V-ring provided with a lip portion having elasticity.

According to the present invention, when the rotary shaft stops or rotates at a low speed, the seal member is supplied to the rotary shaft or the housing by supplying air through the second air supply path and discharging the air to the seal member. To seal between the housing and the rotating shaft. Therefore, it is possible to prevent a situation in which the seal member is lifted by a centrifugal force generated by the rotation of the rotating shaft, although it is low speed, and the gap is opened, and reliable contact prevention is achieved by the contact-type seal mechanism using the seal member. The effect can be expected. On the other hand, when the rotating shaft rotates at a high speed, air is supplied and discharged through the first air supply path, and the seal member is pushed up to be in non-contact with the rotating shaft or the housing. The life of the seal mechanism can be extended without being consumed by frictional heat or the like. Furthermore, although the sealing member is opened without contact, the space between the housing and the rotating shaft is sealed by the air discharged through the first air supply path, thus impairing the effect of preventing the cutting fluid from entering the housing. There is no.
According to a second aspect of the present invention, a concave groove is formed on the front surface of the housing, the first air supply path is opened in the concave groove, and a discharge path communicating with the outside of the housing is provided. A cylindrical portion that fits into the groove is projected from the protruding portion, and a slinger is provided in the cylindrical portion. Therefore, even if the cutting fluid enters the concave groove, the penetrating cutting fluid can be reliably discharged out of the housing by the slinger and the centrifugal force generated by the rotation of the rotating shaft. In particular, during high-speed rotation at which the cutting fluid is likely to enter the concave groove, a larger centrifugal force acts, so that it is possible to expect reliable discharge of the entering cutting fluid .
Further, according to the invention of claim 3, the flange having a diameter larger than the opening position of the second air supply path provided on the front surface of the housing is provided on the projecting portion of the rotating shaft, and the second air supply path is formed by the flange. The rotating shaft is supported by the housing so that the front surface of the opening is covered, and the air discharged through the second air supply path seals between the housing and the flange of the rotating shaft (that is, between the housing and the rotating shaft). It is possible. Therefore, at the time of low-speed rotation, not only the sealing effect by the sealing member but also the sealing effect by the air discharged through the second air supply path can be expected, and the situation that the cutting fluid enters the housing. It can prevent more reliably.
In addition, according to the invention of claim 4, a V-ring having an elastic lip portion is employed as the seal member. Therefore, as the air is supplied through each air supply path, it becomes reliable and easy to open / close the seal member, and it is advantageous in terms of cost.

  Hereinafter, a seal mechanism for a rotating shaft according to an embodiment of the present invention will be described with reference to the drawings. In the present embodiment, the rotating shaft will be described as a rotating shaft provided in a table that performs rotation indexing of the workpiece at low speed rotation or rotationally supports the workpiece being processed at high speed rotation.

FIG. 1 is an explanatory cross-sectional view showing a sealing mechanism provided between the housing 1 and the rotating shaft 2. 1 will be described as the front-rear direction of the housing 1 or the like (the left side of FIG. 1 is the front side of the housing 1 or the like).
Reference numeral 1 denotes a housing that rotatably supports the rotating shaft 2 via a ball bearing 20. A concave groove 3 in which the cylindrical portion 4 of the rotating shaft 2 can be fitted is provided on the front end surface of the housing 1. ing. The concave groove 3 is provided with a discharge path 5 that communicates with the outside of the housing 1, and water, cutting fluid, and the like that have entered the concave groove 3 can be discharged to the outside of the housing 1 through the discharge path 5. A first air supply path 6 is connected to the groove 3 of the housing 1 so that air can be discharged into the groove 3 from a supply source (not shown) under the control of a control device (not shown). It is said. Further, an opening of the second air supply path 7 is provided on the outer peripheral edge of the front end surface of the housing 1 (on the outer peripheral side of the concave groove 3). Like the first air supply path, under the control of the control device, Air can be discharged from the opening of the second air supply path 7.

On the other hand, the rotary shaft 2 supports the workpiece at the time of machining at a low speed when the workpiece is indexed under the control of the control device (for example, in a lathe or a cutting machine). In such a case, the flange 8 is rotated at a high speed and covers the front end surface of the housing 1 (the housing 1 and the flange 8 are not in contact with each other). A concave portion 10 is provided on the rear surface of the flange 8, and a cylindrical portion 4 that protrudes rearward is integrally provided in the concave portion 10. A slinger 9 is provided at a rear end portion of the cylindrical portion 4 (a portion located in the concave groove 3 when the rotary shaft 2 is installed as will be described later). Water that has entered the groove 3 can be efficiently discharged to the outside.
The rotating shaft 2 having such a configuration is installed in a state where the cylindrical portion 4 is fitted into the concave groove 3 of the housing 1. In the installed state, the recess 10 covers the front surface of the second air supply path 7 and functions as a storage space for storing the V ring (seal member) 11. Further, by inserting the cylindrical portion 4 into the concave groove 3, the portion functions as a so-called labyrinth.

And in the storage space, the V ring 11 which is a contact-type seal mechanism is installed as follows.
The V ring 11 is an end face V-shaped ring body made of an elastic synthetic resin or the like, and the lip portion 12 is between the concave groove 3 and the opening of the second air supply path 7 and the front end face of the housing 1. It is installed on the outer periphery of the base portion of the cylindrical portion 4 (in the concave portion 10) so as to come into contact with. That is, the V-ring 11 is installed so that the lip portion 12 covers the outer periphery of the concave groove 2 in contact with the housing 1, and the lip portion 12 allows water or the like to be inside the concave groove 3 (that is, The situation of entering into the shaft side of the rotary shaft 2 is prevented.

Here, the operation of the sealing mechanism having the above-described configuration will be described.
When rotating the rotating shaft 2 at a low speed, the control device supplies air via the second air supply path 7 and discharges air into the recess 10 from the opening. And the intrusion of water or the like from the outer peripheral edge of the flange 8 of the rotating shaft 2 is prevented by the discharged air. Further, the discharged air presses the lip portion 12 inside the opening of the second air supply path 7 against the front end surface of the housing 1 (because the lip portion 12 is pressed against the air from the outer peripheral surface side. Therefore, the intrusion of water or the like into the concave groove 3 and the intrusion of water or the like into the housing 1 is surely prevented.

On the other hand, when rotating the rotating shaft 2 at high speed, the control device supplies air through the first air supply path 6 and discharges the air into the concave groove 3. Then, the air discharged into the concave groove 3 pushes up the lip portion 12 so that the lip portion 12 and the front end surface of the housing 1 are not in contact with each other, and water from the outer peripheral edge of the flange 8 of the rotating shaft 2 or the like. Prevent intrusion. In addition, even though air is discharged, water or the like may enter the groove 3, but water or the like that has entered the groove 3 is centrifuged by the rotation of the rotary shaft 2 at a high speed. The force is discharged to the outside of the housing 1 through the discharge path 5.
Note that a predetermined limit rotational speed at which the lip portion 12 is not damaged is preset in the control device. Then, the control device detects the rotation speed of the rotating shaft 2, determines whether or not the detected rotation speed exceeds the limit rotation speed, and switches the supply path for supplying air.

  According to the sealing mechanism having the above-described configuration, when the rotary shaft 2 rotates at a low speed, the contact-type sealing mechanism by the lip portion 12 of the V ring 11 ensures that water or the like enters the housing 1. Can be prevented. In addition, since air is supplied through the second air supply path 7 to prevent intrusion of water or the like by discharging air, intrusion of water or the like into the housing 1 can be extremely reliably prevented. .

  On the other hand, when the rotary shaft 2 rotates at a high speed, air is supplied through the first air supply path so that the lip portion 12 and the front end surface of the housing 1 are not in contact with each other. However, there is no situation in which the seal performance deteriorates due to wear or frictional heat, and the life of the seal mechanism can be extended. Further, by supplying air through the first air supply path, it is possible to prevent intrusion of water or the like using the discharge of air. Further, since the groove 3 is provided and the cylindrical portion 4 of the rotating shaft 2 is fitted into the recessed groove 3, a labyrinth is formed between the housing 1 and the rotating shaft 2. It prevents water from entering the inside easily. In addition, since the discharge path 5 communicating with the outside is provided in the groove 3, even if water or the like has entered the groove 3, the slinger 9 provided in the cylindrical portion 4 and the rotating shaft Due to the centrifugal force generated by the rotation of 2, the infiltrated water and the like can be reliably discharged out of the housing 1.

  Further, since the V ring 11 is provided on the inner side of the opening of the second air supply path 7, the air is supplied from the second air supply path 7 so that the lip portion 12 of the V ring 11 is placed on the front end surface of the housing 1. It will be pressed. Therefore, although the speed is low, it is possible to prevent the lip portion 12 from being lifted by the centrifugal force generated by the rotation of the rotating shaft 2, and the sealing performance by the V ring 11 can be improved. In particular, when shifting from high-speed rotation to low-speed rotation, the lip portion 12 can be reliably and promptly pressed against the front end surface of the housing 1 by switching the air supply path, resulting in extremely higher sealing performance than before. It can be demonstrated.

  The configuration related to the seal mechanism of the present invention is not limited to the mode described in the above embodiment, and the shape of the housing and the rotary shaft, the shape and installation position of the seal member, the position of the air supply path, The number, the presence / absence of a slinger, the configuration related to the switching of the air supply path, and the like can be appropriately changed as necessary without departing from the spirit of the present invention.

  For example, in order to more efficiently discharge air to the seal member, an air supply path may be provided obliquely so that the installation position of the seal member is on an extension line in the air discharge direction. . Further, the supply amount to the second air supply path may be set smaller than the supply amount to the first air supply path in relation to the supply amount (discharge amount) of air. The case where air is supplied to the second air supply path is a case where sealing is performed by a sealing member. Therefore, when the supply amount to the second air supply path is reduced, the sealing performance does not deteriorate so much. On the contrary, it is possible to expect the effect that the consumption of air can be suppressed. In addition, not only when the rotating shaft is rotated at a low speed, but also when the rotating shaft is stopped or when the rotating shaft is in a stopped state, air may be supplied via the second air supply path.

Further, in the above embodiment, the first air supply path is separately provided in the housing, but there is no problem even if the gap between the housing and the rotating shaft in the housing is used as the first air supply path. Furthermore, in the above-described embodiment, the configuration in which the seal member is installed on the rotation shaft is adopted, but the configuration may be such that the seal member is installed on the front side of the housing, and even if it is installed on the housing side, the rotation shaft The same effect as when installed on the side can be expected.
In the above-described embodiment, the seal mechanism for the rotary shaft provided in the table that supports the workpiece is used. However, the seal mechanism for the rotary shaft provided in the main shaft of a lathe, a grinding machine, or various machining centers may be used. Of course it is possible.

It is sectional explanatory drawing shown about the sealing mechanism which concerns on this invention. It is sectional explanatory drawing which showed the conventional sealing mechanism.

Explanation of symbols

  1 .. Housing 2.. Rotating shaft 3.. Recessed groove 4.. Cylindrical part 5 .. Discharge path 6.. 1 Air supply path 7 7. Flange, 9 ... Slinger, 10 .... Recess, 11 .... V-ring, 12 .... Lip.

Claims (4)

Provided between the rotating shaft rotational speed is controlled me by the rotatable control device in the longitudinal direction as an axis, a housing for rotatably supporting while being protruded forward of the rotary shaft forwardly A sealing mechanism for a rotating shaft that seals between the housing and the rotating shaft in order to prevent the penetration of cutting fluid into the housing,
A first air supply path for supplying air is opened on the front surface of the housing between the protruding portion of the rotating shaft and the front surface of the housing, and contact / non-contact with the protruding portion of the housing or the rotating shaft. A sealing member that closes / opens the space between the housing and the rotating shaft is provided on the outer peripheral side of the opening of the first air supply path, and further, the seal is provided on the outer peripheral side of the sealing member on the front surface of the housing. While opening a second air supply path for discharging air to the member, the control device can switch and supply air between the first air supply path and the second air supply path,
When the rotation shaft stops or rotates at a low speed, the control device supplies the air through the second air supply path and discharges the air to the seal member, thereby causing the seal member to move to the rotation shaft. Alternatively, the seal member is pressed against the housing to seal between the housing and the rotary shaft, and when the rotary shaft rotates at a high speed, air is supplied and discharged through the first air supply path, and the seal member The seal mechanism for the rotary shaft is characterized in that the shaft is pushed out of contact with the rotary shaft or the housing and the space between the housing and the rotary shaft is sealed by the discharged air. A cylindrical groove formed in the front surface of the housing, having a first air supply passage opened in the groove, and provided with a discharge passage communicating with the outside of the housing, while being fitted into the groove on the protruding portion of the rotating shaft Projecting part, provided with a slinger in the cylindrical part,
2. The rotary shaft seal according to claim 1, wherein the cutting fluid that has entered the concave groove can be discharged to the outside of the housing through the discharge path by a rotation operation of the rotary shaft. mechanism.   A flange having a diameter larger than the opening position of the second air supply path provided on the front surface of the housing is provided at the projecting portion of the rotation shaft, and the rotation shaft is configured such that the front surface of the opening of the second air supply path is covered with the flange. 3. The rotation according to claim 1, wherein the housing is supported, and the space between the housing and the flange of the rotating shaft can be sealed by the air discharged through the second air supply path. Shaft seal mechanism.   4. The rotary shaft sealing mechanism according to claim 1, wherein the sealing member is a V-ring having an elastic lip portion.

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