WO1992008271A1

WO1992008271A1 - Non-contact type shaft seal device

Info

Publication number: WO1992008271A1
Application number: PCT/JP1991/001479
Authority: WO
Inventors: Kosei Nakamura; Yukio Katsuzawa; Shinichi Kinoshita
Original assignee: Fanuc Ltd
Priority date: 1990-10-31
Filing date: 1991-10-29
Publication date: 1992-05-14
Also published as: JP2818022B2; JPH04168946A

Abstract

A non-contact type shaft seal device simplified in construction, made at low costs, capable of being installed in a limited space and high in liquid-tight effect. This device is constructed such that a gap formed between a housing and an output shaft in an opening is blocked to control flow of liquid between said housing of an electric motor, having the opening opposable to a coupled machine and said output shaft of the electric motor, rotatably supported by said housing and extending through said opening of said housing. First annular plate member (24) is fixed at the outer peripheral edge thereof to a portion in the vicinity of the opening (20) of the housing, forms at the central portion thereof an insert hole (24b) receiving an output shaft (16) therethrough with a predetermined gap therebetween, and forms a continuous groove (24c), in the shaft end surface of the output shaft, surrounding the insert hole (24b) and having a bottom opposed to the output shaft. Second annular plate member (26) forms at the central portions thereof an insert hole (26a) for receiving the output shaft therethrough, is fixed to the output shaft and is provided so as to be opposed to, separated from, and on the side of the shaft end of, the first annular plate members (24) in a manner to shield the gap formed between the first annular plate member (24) and the output shaft.

Description

Description Non-contact shaft seal device Technical field

The present invention generally relates to a non-contact type shaft sealing device that suppresses movement of a liquid along a rotation axis, and particularly to a non-contact type of a gap between an output shaft of an electric motor and a housing with a liquid such as machine oil. It relates to a shaft sealing device that seals in a formula. Background art

Generally, the output shaft of the motor is integrally connected to the rotor, and is rotatably supported on the motor housing via a bearing. An opening through which the output shaft penetrates is formed on the front surface of the motor housing, that is, an end face for attachment to the mating machine, and a bearing is disposed near the opening to support the output shaft. The front surface of the housing may be exposed to, for example, machine oil such as lubricating oil scattered from a gear mechanism of a mating machine. Therefore, the gap between the inner peripheral surface of the opening and the outer surface of the output shaft is sealed by a liquid-tight means, and the machine oil penetrates into the inside of the motor through the gap to cause a failure due to electric leakage or the like. This eliminates the danger that the grease will seep into the bearings located in the car and flow out of the grease.

Conventionally, when a rotating machine is placed in a state where liquid is scattered around a gap between the machine housing and a rotating shaft penetrating therethrough, a liquid-tight means for sealing the gap with the scattered liquid. Various types of contact-type or non-contact-type shaft sealing devices are known. Among these shaft sealing devices, the means for liquid-tightening the output shaft of the motor against the above-mentioned machine oil, etc. is simple because the pressure difference between the inside and outside of the housing at the shaft sealing portion is small and the mounting space is small. Oil seals were commonly used.

In a well-known oil seal, the lip formed at the tip of the inner periphery of the annular packing made of synthetic rubber or the like always contacts the outer surface of the output shaft while the output shaft is rotating, and slides with each other. However, it is necessary to maintain a lubricated state at this contact part. Such retention of lubrication is assisted by oil droplets of lubricating oil scattered from the gear mechanism of the mating machine. However, in recent years, a method of imparting lubricity to gears and bearings in a gear mechanism section such as a main shaft gear box of a machine tool involves immersing the rotating part in a large amount of lubricating oil in order to reduce the rotational resistance of the rotating member. The transition from the immersion method to the injection method that sprays a predetermined amount of lubricating oil has been started. In this injection method, the amount of lubricating oil supplied to the gear mechanism is smaller than in the immersion method. Therefore, for example, when the main shaft of a machine tool that adopts such an injection system for lubrication of a main shaft gear box is driven by an electric motor equipped with an oil seal on the output shaft, the amount of lubricating oil scattered from the main shaft gear box is reduced. The relatively small amount inevitably reduces the amount of lubricating oil that reaches the lip of the oil seal, resulting in incomplete lubrication. This causes problems such as abnormal heat generation of the lip portion due to friction with the output shaft and reduction of the liquid-tight effect due to abnormal wear. Therefore, it is conceivable to use a non-contact type shaft sealing device having a minute gap between the rotating part on the rotating shaft side and the stationary part on the housing side in a rotating machine. However, in the case of the conventional typical non-contact type shaft sealing device, the labyrinth seal, the labyrinth fin needs to be finely cut to secure a small gap, which is expensive. . In addition, a complicated combination of a rotating member and a stationary member may require a large amount of mounting space, and is not always suitable as a shaft sealing device for an output shaft of a motor. Disclosure of the invention

An object of the present invention is to provide a non-contact type shaft sealing device which has a simple structure, can be manufactured at low cost, and can be installed in a small space, and has a high liquid-tight effect.

Means for Solving the Problems In order to achieve the above object, the present invention provides a static head arranged in a non-contact manner between a housing and a rotating shaft which is rotatably supported by the housing through the housing. A non-contact type shaft sealing device having a stop portion, and closing a gap between the housing and the rotating shaft to prevent a flow of liquid; A through hole is formed in the core to allow the rotation shaft to pass through with a predetermined gap therebetween, and a surface of the rotation shaft protruding outward from the housing on the shaft end side surrounds the through hole. A first annular plate member having a continuous groove having a bottom facing the rotating shaft; and a fitting hole for fitting the rotating shaft in a center portion, and fixed to the rotating shaft. The second annular plate member is disposed on the shaft end side surface of the first annular plate member so as to be spaced apart from each other so as to shield a gap between the first annular plate member and the rotating shaft. A non-contact type shaft sealing device characterized by comprising the above annular plate member.

Further, according to the present invention, a motor housing having an opening capable of facing a mating machine and an output shaft of the motor rotatably supported by the housing through the opening of the housing so as to be rotatable. A non-contact type sealing device having a stationary portion arranged in non-contact with respect to the output shaft, and closing a gap between the housing and the output shaft in the opening to suppress a flow of liquid; A through hole is formed at an outer peripheral edge of the housing, which is fixed to the vicinity of the opening of the housing, and has a central portion formed with a through hole for allowing the output shaft to pass therethrough with a predetermined gap therebetween. A first annular plate member having a continuous groove formed on a surface on the shaft end side of the shaft and surrounding the through hole and having a bottom portion facing the output shaft; and fitting the output shaft in a central portion. Form a fitting hole and exit A first annular plate member fixed to the shaft, and spaced apart from and opposed to the shaft end side surface of the first annular plate member so as to shield a gap between the first annular plate member and the output shaft. A non-contact type shaft sealing device characterized by comprising:

According to a preferred embodiment of the present invention, there is provided the above-mentioned non-contact type shaft sealing device, wherein the second annular plate member has an outer peripheral region inclined toward the first annular plate member.

The first annular plate member fixed to the motor housing is opened. Most of the gap between the housing and the output shaft at the mouth is shielded to catch liquid such as machine oil scattered from the partner machine. The gap between the first annular plate member and the output shaft is shielded by the second annular plate member fixed to the output shaft. When the output shaft rotates, the liquid scattered around the output shaft adheres to the outer surface of the second annular plate member, and is centrifugally generated by the rotation of the second annular plate member together with the output shaft. , It is shaken off in the radial direction. Part of the shaken liquid adheres to the surface of the first annular plate member again. When the output shaft faces vertically downward, the liquid adhering to the first annular plate member falls downward as it is. When the output shaft is oriented horizontally or obliquely, it flows along the surface of the first annular plate member, further flows down while being accumulated in the continuous groove, and is discharged downward. On the other hand, the liquid scattered to a position radially distant from the periphery of the output shaft is directly received by the surface of the first annular plate member, and thereafter discharged to the outside in the same manner as described above. In this way, the gap between the housing and the output shaft at the opening is reliably sealed against the splashed liquid, and the intrusion of the liquid into the motor is prevented. BRIEF DESCRIPTION OF THE FIGURES

The above and other objects, features, and advantages of the present invention will be described based on embodiments shown in the accompanying drawings. FIG. 1 is a longitudinal sectional view of a motor provided with a non-contact type shaft sealing device according to an embodiment of the present invention;

Fig. 2 shows the first annular plate in the non-contact type shaft seal device of Fig. 1. Front view of the material,

FIG. 3 is a front view of a second annular plate member in the non-contact type shaft sealing device of FIG. 1,

FIG. 4 is a front view of a third annular plate member in the non-contact type shaft sealing device of FIG. BEST MODE FOR CARRYING OUT THE INVENTION

Referring to FIG. 1, an electric motor including a non-contact type shaft sealing device according to an embodiment of the present invention is integrally fixed to a bottomed cylindrical housing 10 and an inner peripheral portion of a housing 10. The housing includes a stay 12 and a rotor 14 surrounded by the stator 12 and rotatably supported by the housing 10. The housing 10 includes a front housing 10 a for fixing the stay 12 and forming a mounting end face to the counterpart machine, and a rear housing 10 b for closing a bottom of the housing 10. The output shaft 16 of the motor is integrally fixed to the rotor 14, and passes through the mouth 14, and the bearings 18 a, 18 a, which are respectively housed in the front and rear housings 10 a, 10 b. It is rotatably mounted on 18 b. An opening 20 through which the output shaft 16 penetrates is formed on the end face of the front housing 10a. A bearing 18a of the front housing 10a is attached to the opening 20. The output shaft 16 is supported concentrically. Therefore, an annular gap 22 surrounding the output shaft 16 is formed between the output shaft 16 and the front housing 10a in front of the bearing 18a in the opening 20.

When the above motor is used to drive a machine tool spindle, the spindle Lubricating oil may splash from the gearbox near the end face of the front housing 10a, invading the gap 22 and causing the grease of the bearing 18a to flow out or entering the interior of the motor. In order to prevent the penetration of oil droplets, the electric motor has a non-contact type shaft sealing device according to the embodiment of the present invention disposed close to the opening 20. This non-contact type shaft sealing device is configured by arranging annular sheet metal members 24, 26, 28 shown in FIGS. 2 to 4 in a positional relationship as shown in FIG.

As shown in FIGS. 1 and 2, the first annular plate member 24 has an annular flange 24 a on an outer peripheral edge thereof, and the first annular plate member 24 has an opening 20 at an end face of the front housing i 0 a. The annular flange 24a is fixed to the front housing 10a by, for example, fitting the annular flange 24a into the annular projection 30 formed therearound by shrink fitting or the like. In the center of the first annular plate member 24, a through hole 24b through which the output shaft 16 is inserted with a small gap therebetween is formed. Further, the inner peripheral edge surrounding the through hole 24 b is curved toward the front side facing the shaft end of the output shaft 16, thereby forming a substantially V-shaped section with the bottom portion facing the output shaft 16. A continuous groove 24c is formed.

Also, as shown in FIGS. 1 and 3, the second annular plate member 26 has a central hole formed with a fitting hole 26 a for fitting the output shaft 16, and a fitting hole 26 a It has an annular flange 26b on the inner periphery surrounding it. The second annular plate member 26 is fixed to the output shaft 16 by an annular flange 26b, for example, by shrink fitting, and a gap between the first annular plate member 24 and the output shaft 16 is provided. The first annular plate member 24 is opposed to the front surface of the first annular plate member 24 so as to be shielded from the air. further The second annular plate member 26 has an annular bent portion 26c on the way from the inner peripheral edge to the outer peripheral edge, and the second annular plate member 26 covers the continuous groove 24c of the first annular plate member 24. The first annular plate member 24 has an outer peripheral area 26 d inclined in the direction of the fourth direction. A minute gap is always formed between the periphery of the outer peripheral area 26 d of the second annular plate member 26 and the front surface of the first annular plate member 24.

The above-mentioned non-contact type shaft seal device is provided with the above-mentioned two annular plate members 24 and 26 which make the stationary portion and the rotating portion non-contact with each other, thereby preventing liquid such as lubricating oil or the like from splashing. It is possible to close the gap 22 between the openings 20. However, in the above embodiment, the third annular plate member 2 shown in FIG. 8 is further disposed in front of the second annular plate member 26.

As shown in FIGS. 1 and 4, the third annular plate member 28 has an annular flange 28a formed on the outer peripheral edge thereof, and the first annular plate member 24 It is fitted and fixed in the annular projection 30 of the front housing 10a, for example, by shrink fitting, so as to overlap the inside of the annular flange 24a. The upper half of the third annular plate member 28 is formed with a cover portion 28 b projecting toward the shaft end of the output shaft 16 and extending near the output shaft 16, and an inner peripheral edge of the cover portion 28 b is formed. In addition, an arc-shaped notch 28c is formed to allow the output shaft 16 to be separated from and pass through. The third annular plate member 28 covers the first annular plate member 24 and the second annular plate member 26 with a force bar portion 28b, and is provided between the annular plate members 24 and 26. Shield small gaps. All of the above three annular plate members 24, 26, and 28 can be easily manufactured by press molding and can be easily assembled as described above, so that the cost is low.

The operation of the non-contact type shaft sealing device having the above configuration will be described below.

When the output shaft 16 rotates, the first annular plate member 24 is stationary and covers most of the gap 22 in the opening 20 in front of the bearing 18a. At this time, a minute gap is left between the inner peripheral edge of the first annular plate member 24 and the outer peripheral surface of the rotating output shaft 16. The second annular plate member 26 is arranged in front of the first annular plate member so as to shield this gap, and rotates together with the output shaft 16. The third annular plate member 28 is statically disposed in front of the second annular plate member 26 without contact with the second annular plate member 26 and the output shaft 16.

When this electric motor is mounted horizontally for driving the spindle of a machine tool and operated, oil droplets of lubricating oil scattered from the spindle gear box etc. to the front end face of the electric motor will cause the annular plate members 24, 26, 28 It adheres to the front. First, oil droplets adhering to the front surface of the second annular plate member 26 are radially shaken off along the inclined outer peripheral region 26 d by centrifugal force generated by the rotation of the second annular plate member 26. Attaches to the front surface of the first annular plate member 24. The oil droplets adhering to the first annular plate member 4 flow downward due to the action of gravity, but those adhering above the front surface accumulate in the surrounding groove 24 c provided on the inner peripheral edge, and then the continuous groove. It flows down further along 24c and flows out. The third annular plate member 28 has a cover portion 28 b Thereby, the upper half areas of the first and second annular plate members 24 and 26 are shielded. As a result, the amount of oil droplets accumulated in the continuous groove 24c of the first annular plate member 24 is reduced, and the lubricant oil is prevented from overflowing from the continuous groove 24c. Oil droplets adhering to the outer surface of the cover portion 28b of the third annular plate member 28 flow downward as it is. Further, since the inclined outer peripheral region 26 d of the second annular plate member 26 is arranged so as to cover the continuous gun groove 24 c of the first annular plate member 24, the continuous groove 24 c Prevents the direct accumulation of oil droplets on the oil and prevents the lubricant from overflowing from the continuous groove 24c. In the present embodiment, since the motor is arranged horizontally, the continuous groove 24c is provided not at the entire inner peripheral edge of the first annular plate member 24 as described above but at least in the upper half of the inner peripheral edge. However, it goes without saying that the same effect can be obtained.

As described above, the non-contact type shaft sealing device according to the present invention includes the second annular plate member that rotates integrally with the rotating shaft, and the first annular plate member that comes to rest in non-contact with the rotating shaft. By the combination of the above, it is possible to reliably seal the gap in the penetrating portion between the rotating shaft and the housing through which the rotating shaft operates against the scattered liquid when the rotating shaft is operated. The first annular plate member, which is a stationary portion, and the second annular plate member, which is a rotating portion, and the rotating shaft are always kept in a non-contact state, so that damage due to wear or the like is completely avoided. The same applies to the case where a third annular plate member is further provided as a stationary portion. Therefore, according to the present invention, there is provided a non-contact type shaft sealing device having a high liquid-tight effect, which is simple in structure, can be manufactured at low cost, and can be installed in a small space.

Claims

The scope of the claims

1. a stationary portion disposed between a housing and a rotating shaft rotatably supported by the housing so as to pass through the housing, the stationary portion being arranged in non-contact with the rotating shaft; In a non-contact type shaft sealing device that blocks the flow of liquid by closing the gap with the rotating shaft,

An outer peripheral edge is fixed in the vicinity of the penetrating portion of the housing, a through hole is formed at a central portion for allowing the rotating shaft to pass through with a predetermined gap therebetween, and the rotation protruding outward from the housing is formed. A first annular plate member having a continuous groove formed on a surface on the shaft end side of the shaft and surrounding the through hole and having a bottom portion facing the rotation shaft;

The first annular plate is formed so as to be fixed to the rotating shaft by forming an insertion hole into which the rotating shaft is fitted at the center, and to shield a gap between the first annular plate member and the rotating shaft. A non-contact type shaft sealing device, comprising: a second annular plate member which is opposed to the surface on the shaft end side of the member while being spaced apart from each other.

2. The non-contact type shaft sealing device according to claim 1, wherein the second annular plate member has an outer peripheral region inclined toward the first annular plate member.

3. between the housing of the electric motor having an opening capable of facing the counterpart machine and the output shaft of the electric motor rotatably supported by the housing through the opening of the housing. A stationary part arranged in a non-contact manner relative to the A non-contact type shaft sealing device that closes a gap between the housing and the output shaft in a section and suppresses a flow of a liquid;

An outer peripheral edge is fixed in the vicinity of the opening of the housing, an insertion hole is formed at a central portion for allowing the output shaft to pass through with a predetermined gap therebetween, and the output protruding outward from the housing is formed. A first annular plate member having a continuous groove formed on a surface on the shaft end side of the shaft and surrounding the through hole and having a bottom portion facing the output shaft;

The first annular member is fixed to the output shaft by having a fitting hole for fitting the output shaft in a center portion, and blocking a gap between the first annular plate member and the output shaft. A second annular plate member disposed on the shaft end side surface of the plate member so as to be spaced apart and opposed to each other;

A non-contact type shaft sealing device comprising:

4. The non-contact type shaft sealing device according to claim 3, wherein the second annular plate member has an outer peripheral region inclined toward the first annular plate member.

5. The non-contact type shaft sealing device according to claim 3, wherein the continuous groove of the first annular plate member is formed in at least a part of a periphery of the through hole.

6. The first and second annular plate members are fixed to the housing at an outer peripheral edge and spaced apart from the output shaft at an inner peripheral edge, and are disposed on the shaft end side of the first and second annular plate members; 4. The non-contact type shaft sealing device according to claim 3, further comprising a third annular plate member covering at least a part of the annular plate member.