WO1995005699A1

WO1995005699A1 - Shaft sealing device for an electric motor

Info

Publication number: WO1995005699A1
Application number: PCT/JP1994/001343
Authority: WO
Inventors: Kosei Nakamura; Yukio Katsuzawa; Yasuyuki Nakazawa
Original assignee: Kosei Nakamura; Yukio Katsuzawa; Yasuyuki Nakazawa
Priority date: 1993-08-12
Filing date: 1994-08-12
Publication date: 1995-02-23
Also published as: JPH0755012A

Abstract

A shaft sealing device for an electric motor provided at at least one end of an output shaft (20) of an electric motor (10) and at one end of a stator housing (14) confronting the one end of the output shaft, the shaft sealing device comprising a stationary rim (32) provided on the stator housing (14) and a rotary rim (34) provided in a shaft end area (20a) of the output shaft (20), and further comprising labyrinth means constituted by the two rims (32, 34) and sealing means provided rotatable together with the rotary rim (34) of the labyrinth means and comprising a bottom portion (38a) and a tongue-like portion (38b), wherein the shaft end is sealed by virtue of a contact sealing operation of the sealing means until the motor reaches a predetermined revolution speed, while in a speed range higher than the predetermined revolution speed the shaft end is sealed by virtue of a non-contact sealing operation of the labyrinth means, whereby uniform shaft sealing is effected over a wide range of motor conditions such as from stationary through low speed revolution to high speed revolution conditions by allowing both the contact and non-contact sealing operations to work in combination.

Description

Specification

Shaft sealing device for electric motor

The present invention relates to an electric motor (hereinafter, simply referred to as a motor) generally used as a drive motor of a machine tool or the like, and in particular, to an axis for protecting the inside of the body from moisture and dust outside the body of the motor. The sealing function is a contact-type sealing function in the low-speed range of the motor, and a non-contact labyrinth-type sealing function in the high-speed range, so that it covers a wide range from the low-speed rotation range to the high-speed rotation range. The present invention relates to a shaft sealing device for a motor having a composite shaft sealing function capable of exerting a uniform sealing function across the entire shaft.

Background art

It is well-known that not only motors but also rotary equipment with rotating shafts are provided with shaft seals to provide waterproofing and dustproofing. A shaft sealing device is provided, and foreign matter such as dust from the outside of the motor machine and liquid such as machining fluid and lubricating oil at the machine tool site enter the inside of the bearing inside the motor body or a narrow area, and the mechanical It is well known that electrical functions are prevented from deteriorating.

As a shaft sealing device for a conventional motor, in the case of a motor whose output shaft rotates at a relatively low speed range of up to 5,000 rpm, the closest to the rotary bearing in the stator housing The seal holding part is recessed on the outer part of the metal frame, and the synthetic rubber material such as acrylic rubber, double rubber, fluorine rubber, etc. is sintered into the metal frame and fixed into the seal holding part. The structure was adopted to prevent foreign matter and contamination source liquid from entering from outside by fitting the oil seal to the surface and keeping the oil seal in contact with the surface of the rotating output shaft. On the other hand, when the motor is used in the so-called high-speed rotation range, the motor rotates and non-rotates at the output shaft carrying the rotor at the center and the position immediately adjacent to the rotation bearing of the stay housing, respectively. Attach a pair of metal block-shaped bodies, or provide them integrally, and provide a labyrinth-shaped gap with both block-shaped bodies to form a well-known labyrinth in a non-contact state In addition, it is effective to use a structure that prevents foreign matter and contamination source liquid from entering from outside during the rotation of the motor in the same labyrinth region.

However, if the former shaft seal device using an oil seal is applied to a high-speed rotating motor, the sealing characteristics of the oil seal deteriorate with time due to heat generated by frictional heat at the lip where the oil seal contacts the rotary output shaft. In addition, there is a problem that the sealing function is deteriorated due to wear and wear, and the durability is remarkably reduced, and the practicability is poor.

On the other hand, the latter shaft seal device using labyrinth prevents intrusion through the labyrinth during high-speed rotation because a pair of block-shaped members are provided in a non-contact manner. While the shaft sealing function can be demonstrated, it has the disadvantage that the sealing function cannot be performed when the motor is stationary or when the motor is used in a low-speed rotation range.

Disclosure of the invention

Accordingly, an object of the present invention is to provide an electric motor capable of reliably and uniformly generating a shaft sealing function particularly in a wide motor rotation range from a low-speed rotation range to a high-speed rotation range. The company does not provide a shaft sealing device.

Another object of the present invention is to provide an electric motor capable of exhibiting a proper shaft sealing function from a high-speed rotation range to a low-speed rotation range and a stationary range of a motor while having a relatively small and compact structure. An object of the present invention is to provide a shaft sealing device for a motor.

In view of the above-mentioned object, the present invention provides a contact seal at a low speed of a motor. By forming stop means and non-contact labyrinth-type sealing means in the high-speed range, a uniform sealing action can be achieved over the entire stationary and low-to-high-speed rotation range of the motor. A sealing unit having a multiple sealing function is formed while being formed as a single unit that exerts its function, and this is provided in the shaft end region of the output shaft of the motor. is there.

That is, according to the present invention, in a shaft sealing device provided between the housing of the electric motor and at least one shaft end region of the rotary output shaft,

Lapince forming means formed by a rotating rim provided in a shaft end region of the output shaft and a stationary rim provided at an end of the stay housing opposed to the rotating rim;

An annular seal chamber formed between the rotating rim and the stationary rim of the lapilis forming means and disposed on a periphery of a shaft end region of the output shaft, and housed in the annular seal chamber; And contacting the stationary rim and the base fixed to the rotating rim or the output shaft integrally with the stationary rim from a stationary speed to a predetermined rotational speed to seal the interior of the stay housing and the predetermined A sealing means having a tongue-shaped seal portion which is centrifugally separated from the stationary rim in a high rotation speed region exceeding the rotation speed;

A shaft sealing device for an electric motor comprising: Preferably, the rotating rim of the above-mentioned labyrinth forming means comprises a first annular member having an L-shaped cross section formed integrally with the output shaft, and the labyrinth forming means. The stationary rim of the means comprises a second annular member having an L-shaped cross section formed integrally with the stay housing, and between the first and second L-shaped annular members. The annular seal chamber is formed.

Preferably, the sealing means provided with the base portion and the tongue-shaped seal portion is a molded member formed of a synthetic rubber material. Preferably, the tongue-shaped seal portion of the sealing means has a weight means for promoting a separating action from the stationary rim by centrifugal action when the output shaft reaches a predetermined rotation speed range. It may be configured to be built-in, so that the separating action of the tongue is adjusted.

Preferably, the weight means comprises a mass body embedded in the sealing means molded from the synthetic rubber material, and the mass body is a metal or resin material.

According to the above configuration, in the low-speed region of the motor, the tongue-shaped seal portion of the sealing means comes into contact with the stationary rim of the labyrinth forming means to cut off communication between the outside of the motor and the inside of the motor. In the high rotation region, the tongue of the sealing means is separated from the stationary rim by centrifugal action and formed by the rotating rim and the stationary rim while preventing wear and heat generation. The labyrinth makes it possible to prevent foreign substances and liquids of pollution source from entering the motor from outside the motor.

BRIEF DESCRIPTION OF THE FIGURES

The above and other objects, features, and advantages of the present invention will be further clarified with reference to the accompanying drawings.

FIG. 1 is a partial cross-sectional view illustrating a shaft sealing function in a low-speed rotation state of an electric motor including a shaft sealing device according to the present invention,

Fig. 2 is a partial cross-sectional view illustrating the shaft sealing function of the electric motor in a high-speed rotation state.

Fig. 3 is an enlarged view of part A in Fig. 1,

Fig. 4 is an enlarged view of part B in Fig. 2,

FIG.5A is a partial cross-sectional view showing another embodiment of the shaft sealing device according to the present invention,

FIG. 5B is a cross-sectional view taken along arrow 5B—5B in FIG. 5A.

FIG. 6 is a diagram showing the characteristics of the shaft sealing device for an electric motor according to the present invention. FIG.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring to FIGS. 1 and 2, there is shown a cross-sectional view of a front half of an electric motor 10. The motor 10 has a cylindrical stator housing a stator winding 12. The bearing 14 has a bearing 14 and an end 14 of the housing 14, and the rotating bearing 16 (the front end of the front-rear pair) is seated on the bearing holder 14 a at the end of the housing 14. An output shaft 20 having a rotor 18 at the center is provided rotatably via a bearing.

Here, according to the present invention, the shaft sealing device 30 includes the outer region of the bearing holding portion 14 a in the end region of the housing 14, and the shaft of the output shaft 20 opposed thereto. It is provided in the end region 20a.

Here, the coaxial sealing device 30 has a stationary rim 32 provided substantially integrally with the bearing holding portion 14a of the stator housing 14 as a stationary element. The stationary rim 32 has a disk portion 32a extending in the circumferential direction with respect to the rotation axis of the output shaft 20 and a cylindrical portion 32b extending in the radial direction with respect to the rotation axis of the output shaft 20. The cylindrical portion 32b has an annular outer surface with the outer peripheral surface of the shaft end region 20a of the output shaft 20. It is opposed to the inner end via an annular minute gap.

On the other hand, a rotating rim 34 formed substantially integrally is provided in the shaft end region 20a of the output shaft 20. The rotating rim 34 is a disk portion 3 2 of the stationary rim 32. It is composed of an L-shaped member having a radial disk portion 34a substantially parallel to a and an annular portion 34b protruding in the axial direction from the outer peripheral area of the radial disk portion 34a. The outer peripheral surface of the part 34 b has an annular cylindrical minute gap between the outer peripheral surface of the stay housing 14 and the inner peripheral surface of the tip of the housing 14, and one part of the disk part 3 2 a of the stationary rim 32. An annular disk-shaped minute gap is formed at the part facing the part. That is, the stationary rim 3 2 and the rotating rim 3 described above 4 forms the above-mentioned four small gaps around the shaft end of the output shaft 20, thereby forming a labyrinth, and the rotation speed of the output shaft 20 of the motor 10 reaches a high speed. And dust that enters from inside the motor housing toward the interior of the stator housing 14 and the rotary bearing 16, and moisture and oil that can be intruded by the surrounding motor operating environment. Performs both dustproof and waterproof functions.

In addition, an inner chamber (seal chamber) 36 surrounded by the stationary rim 32 and the rotating rim 34 of the shaft sealing device 30 described above has the same composition as a conventionally known oil seal element. A seal member 38 made of a rubber material is fixed. The seal member 38 has an annular base 38a and a tongue 38b, and is fixed to the annular portion 34b of the rotary rim 34 by the base 38a. The tongue-shaped portion 38b is directed toward the outer peripheral surface of the cylindrical portion 32b of the stationary rim 32 so as to form a substantially V shape from one end of the base 38a. It hangs down in a cantilever manner and is provided so that it can contact the outer peripheral surface.

As shown in FIG. 1, the tongue-shaped portion 38b of the sealing member 38 elastically engages with the cylindrical portion 32b of the stationary rim 32 when the motor 10 rotates at a low speed. The outside of the motor unit and the inside of the motor unit are isolated and sealed in the internal chamber 36 by contacting the outer peripheral surface.

Then, as shown in FIG. 2, when the output shaft 20 of the motor 10 reaches a high-speed region exceeding a predetermined rotation speed, the tongue-shaped portion of the seal member 38 that rotates integrally is used. A centrifugal force acts on 38 b in proportion to the material density of the seal member 38, so that the tongue 38 b extends in the circumferential direction, and as a result, the motor rotation axis of the tongue 38 b The radius about the heart increases. As a result, the tongue portion 38b of the seal member 38 separates from the cylindrical portion 32b of the stationary rim 32 that was in contact during low-speed rotation. Therefore, the tongue 38b of the seal member does not contact the stationary rim 32 during high-speed rotation. Because it is maintained, there is no fear of heat generation or wear.

As described above, while the motor 10 is rotating in the high-speed rotation range, the sealing function of the sealing member 38 is lost, but the above-described operation formed by the stationary rim 32 and the rotating rim 34 is performed. In the labyrinth consisting of the four small annular gaps, the high-speed rotation provides a sufficient sealing function and prevents dust, water, oil, etc. from entering the motor from outside the motor. .

FIG. 3 is an enlarged view of a state in which the sealing member 38 of the shaft sealing device 30 performs a contact-type sealing operation in the low-speed rotation range of the motor. In this way, the sealing member 38 contacts the cylindrical portion 32b of the stationary rim 32 and reliably shuts off the outside of the motor 10 from the inside of the motor 10 in the internal chamber 36. Therefore, even when the motor stops rotating, the shaft is naturally sealed to prevent dust and water.

Also, from FIG. 4, in the high-speed rotation range, the tongue-shaped portion 38b of the sealing member 38 is separated from the stationary rim 32 to maintain a non-contact state, while the labyrinth It can be understood that the shaft sealing action is achieved.

FIGS.5A and 5B show another embodiment of the shaft sealing device 30 according to the present invention, and this embodiment is different from the above-described embodiments of FIGS. The mass 40 made of metal or an appropriate resin material is embedded in the tongue 38 b of the seal member 38 of the shaft seal device 30 to actively adjust and change the material density of the seal member 38. By adjusting the effect of the centrifugal force acting on the tongue 38b at the time of high-speed rotation, the contact-type shaft seal and the non-contact rubber at the low-speed rotation and high-speed rotation of the motor 10 are rotated. The boundary region with the ring type shaft seal can be adjusted to an appropriate speed point in consideration of the speed region of the practical motor.

In this case, the mass of the mass body 40 itself is The experimental results were obtained in terms of the relationship between the switching speed from the shaft seal to the lip-shape seal, and the seal member 38 was formed at the stage of forming the seal member 38 with synthetic rubber. Embedded and enclosed in. Then, as shown in FIGS. 5A and 5B, the centrifugal force can be exerted by distributing and arranging at equal intervals around the circumference inside the tongue 38 b of the sealing member in advance during the molding process. Acts uniformly on the circumference, and it is possible to cause the separating action of the tongue 38b of the seal member 38 in the set rotation speed range. In Fig. 6, the horizontal axis indicates the number of rotations of the motor 10 per unit time, the vertical axis indicates the centrifugal force, and the seal member 38 of the shaft sealing device 30 according to the change in the number of rotations is stationary. It is a curve showing the situation where it is separated from the rim 32 side.

In FIG. 6, the point P at points P, Q, and R on the curve is the rotation speed at which the labyrinth formed by the stationary rim 32 and the rotating rim 34 starts the shaft sealing function. However, the centrifugal force acting on the seal member 38 at that rotation speed is at a relatively low level, and the tongue portion 38b still shows the contact-type sealing function.

The point Q is that the tongue 38b of the sealing member 38 of the shaft sealing device 30 gradually increases in centrifugal force as the rotation speed gradually increases, and the cylindrical portion 32 of the stationary rim 32. This indicates the point where the separation from b starts and therefore the contact-type sealing function is lost.

Further, point R is a permissible peripheral speed point at which the sealing function can be maintained if the sealing member 38 of the shaft sealing device 30 does not separate from the cylindrical portion 32 b of the stationary rim 32. Is shown.

In the present invention, the rotational speed position Q at which the sealing member 38 deviates from the contact state with the stationary rim 32 is defined as the labyrinth sealing start speed point P and the permissible peripheral speed point of the sealing member 38. By setting the distance between R and R, even when the electric motor 10 is used in a wide speed range from a stationary rotation state to a high-speed rotation range, the seal member 38 of the shaft sealing device 30 is used. Contact type sealing The non-contact labyrinth-type sealing with the labyrinth and the labyrinth acts sequentially to achieve dustproof and waterproof inside the motor body from outside the motor body.

As is evident from Fig. 6, the shaft sealing function of the contact-type sealing and the non-contact-type sealing is acting redundantly between the points P and Q. Since there is no interruption time, a highly reliable shaft sealing device can be configured.

In the embodiment shown in FIGS. 5A and 5B, the rotational speed position at the point Q can be appropriately adjusted in consideration of the practical rotational speed of the motor. Also, in the figure, the shaft sealing device provided on the front side of the motor 10 is shown, but it goes without saying that a similar shaft sealing device is provided on the rear end side as well.

As is clear from the above description, the shaft sealing device for an electric motor according to the present invention, when the motor is used for a drive motor of a machine tool, changes from a stationary state of zero rotation speed to machining by high-speed rotation. The oil-sealing contact-type sealing function and the labile-type non-contact sealing function function sequentially and in combination throughout the operation, so the waterproof and dustproof performance of the motor is highly reliable. It can be demonstrated under gender.

Therefore, it is possible to extend the life of the motor and to extend the application of each electric motor.

Claims

The scope of the claims

1. In a shaft sealing device provided between the stator housing of the electric motor and the shaft end area of the rotary output shaft,

A limb formed of a rotating rim provided at least in one shaft end region of the output shaft and a stationary rim provided at an end of the stay housing opposed to the rotating rim. Means of violence,

An annular seal chamber formed between the rotating rim and the stationary rim of the labyrinth means and disposed around a shaft end region of the output shaft;

The stationary housing is housed in the annular seal chamber and is fixedly connected to the rotating rim or the output shaft, and the stationary rim contacts the stationary rim from a stationary speed to a predetermined speed to seal the interior of the stay housing. A sealing means having a tongue-shaped seal portion which stops and centrifugally separates from the stationary rim in a high rotation range exceeding the predetermined speed;

A shaft sealing device for an electric motor characterized by comprising:

2. The shaft sealing device for an electric motor according to claim 1, wherein the rotating rim of the labyrinth forming means has a first annular shape formed integrally with the output shaft and having an L-shaped cross section. Consisting of members,

The stationary rim of the Labyrinth forming means comprises a second annular member having an L-shaped cross section formed integrally with the stay housing, and the first and second L A shaft sealing device for an electric motor, wherein the annular seal chamber is formed between the U-shaped annular members.

3. The shaft sealing device for an electric motor according to claim 1, wherein the sealing means including the base portion and the tongue-shaped sealing portion is a molded member formed of a synthetic rubber material. The electric motor Shaft sealing device for

4. The shaft sealing device for an electric motor according to claim 3, wherein the tongue-shaped seal portion of the sealing means is provided with a centrifugal action when the output shaft reaches a predetermined rotation speed range. A shaft sealing device for an electric motor, characterized in that a weight means for promoting a separating action from the stationary rim is built in, so that the separating action of the tongue-and-fold portion is adjusted.

5. The shaft sealing device for an electric motor according to claim 4, wherein the weight means comprises a mass body embedded inside the sealing means molded from the synthetic rubber material, wherein the mass body is made of metal. Or a shaft sealing device for an electric motor characterized by being made of a resin material.