JPS582938Y2 - Sealing device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a sealing device for sealing liquid leakage between a rotating member and a fixed member facing the rotating member, in which the sealing member is attached to the rotating member by an elastic member having elasticity and flexibility. constitutes a contact type sealing device in which the lip is pressed against the fixed member by the elasticity of the elastic member, and as the rotational speed of the rotating member increases, the lip is fixed using centrifugal force. The purpose of this is to weaken the force that presses the member into contact and reduce the sliding frictional resistance of the contact portion.

That is, in the present invention, a hollow cylindrical sealing member is fixed to the free end edge of an elastic member made of a thin plate having an approximately truncated conical shape with the central axis of rotation of the rotating member as the central axis. By fixing the sealing member to the rotating member via an elastic member, a force is generated to move the sealing member in the axial direction by the action of centrifugal force accompanying the rotation of the rotating member. A bottomed groove formed by opposing a sealing surface formed on a cylindrical surface centered on the rotation center axis and a sealing surface formed on a truncated conical surface inclined in the same direction as the truncated conical surface shape of the elastic member. The sealing member is placed in the groove, and the lip of the sealing member is pressed against the truncated conical sealing surface of the fixing member by the elasticity of the elastic member. The pressure force of the lip is reduced by the force of moving the lip in the axial direction, and the sealing member has a cylindrical sealing surface that concentrically faces the cylindrical sealing surface formed on the fixed member with a slight gap therebetween. A labyrinth groove is formed on one or both of these cylindrical seal surfaces, and a labyrinth seal is formed between both cylindrical seal surfaces to seal liquid leakage during rotation of the rotating member. This produced a sealing effect.

An embodiment of the present invention will be described in detail below.

The drawing shows a sealing device for sealing liquid leakage between a fixed member 1 and a rotating shaft 2 rotatably supported by the member 1.
The main parts are shown by cutting along a plane that includes the center axis of rotation. Figure 1 shows the state of the rotating shaft 2 when it is stopped, and Figure 2 shows the state of the rotating shaft when it is rotating at high speed. .

The rotating shaft 2 is formed with a small diameter part 3 with a threaded part and a step part 4 connected thereto, and a locking nut 5 and a cylindrical nut 6 are screwed onto the small diameter part 3 so as to abut against the step part 4. elastic member 1
The elastic member 7 is fixed to the rotating shaft 2 by pinching the inner peripheral edge of the elastic member 7.

The elastic member 7 is formed by press-molding an annular thin plate made of a material with high elasticity and flexibility, such as spring steel, into a substantially truncated conical shape.

Therefore, the inner circumferential edge of the elastic member 7 is a circumferential edge that almost fits into the small diameter portion 3 of the rotating shaft 2, and the outer circumferential edge is a circular free end centered on the rotation center axis O-O of the rotating shaft 2. The inner and outer surfaces thereof are sloped such that the outer circumferential edge is to the left of the inner circumferential edge as shown in FIG.

Near the free end of the elastic member T, a sealing member 8 made of a hollow cylindrical elastic material such as rubber or synthetic rubber, such as nitrile rubber, is arranged such that the center axis of the member 8 is aligned with the rotation center axis 0-O. , and one open end thereof is fixed to one side of the elastic member 7.

A suitable weight 9 is placed inside the seal member 8 with a central axis O-O.
Place and bury it in the proper place so that there will be no imbalance.

The opening of the fixing member 1 has a bottomed groove formed by opposing a sealing surface 10 formed in a cylindrical surface with the rotational center axis 0-O as the central axis and a sealing surface 11 formed in a truncated conical surface. An annular ring member 13 having 12 formed on the side surface is fixed.

The frusto-conical seal surface 11 is tilted from the central axis OO so that the inclination directions of the frusto-conical seal surface 11 and the elastic member 7 formed in the frusto-conical shape are in the same direction. The diameter is inclined such that the diameter at the left end is more dog-shaped than the diameter at the right end in FIG.

The ring member 13 and the seal member 8 are associated with each other and fixed to the fixed member 1 and the rotating shaft 2, respectively, as follows.

That is, substantially the entire seal member 8 is inserted into the bottomed groove 12.

Since the inclinations of the frustoconical surface shape of the elastic member T are in the same direction, the lip 14 formed at the inner peripheral end of the free end edge of the sealing member 8 abuts against the frustoconical sealing surface 11 of the ring member 13. The cylindrical sealing surface 10 of the ring member 13 and the cylindrical sealing surface 15 formed on the outer periphery of the sealing member 8 are separated by a slight gap. facing each other, both sides 10
．． Labyrinth grooves 16 and 17 are formed in each of the grooves 15 to form a labyrinth seal between both surfaces.

In the figure, reference numeral 18 indicates a labyrinth groove carved in the inner circumferential wall 19 formed on the cylindrical surface of the ring member 13.

The sealing device having the above configuration is constructed between the fixed member 1 that constitutes the outer wall of the chamber 20 and the rotating shaft 2 in order to seal the leakage of liquid from the chamber 20 where oil lubrication is performed to other chambers 21. At this time, the lip 14 of the sealing member 8 is pressed against the frustoconical sealing surface 11 of the ring member 13 by the elasticity of the elastic member 7, not only when the rotating shaft 2 is stationary but also when the shaft 2 is rotating at a low speed. , surface contact to seal liquid leakage from chamber 20 to chamber 21.

As the rotation of the rotating shaft 2 becomes faster, a centrifugal force in a radial direction centered on the axis O-O acts on the sealing member 7 due to the rotational speed, and the centrifugal force is applied to the substantially truncated conical surface of the elastic member 7. Due to the inclination of the shape, the elastic member 7 is bent to the right in FIG. This results in the lip 14 being separated from the sealing surface 11.

However, the cylindrical sealing surface 15 of the seal member 8 and the cylindrical sealing surface 10 of the ring member 13 face each other with a slight gap between them, and labyrinth grooves 17 are formed in both sealing surfaces 15 and 10. .16 forms a labyrinth seal, even if the lip 14 of the seal member 8 separates from the truncated conical seal surface 11, liquid leakage from the chamber 20 to the chamber 21 during high speed rotation of the rotating shaft 2 is prevented. is sealed by a labyrinth seal.

In this embodiment, as shown in FIG. 3, the elastic member 7 has the remaining parts except for the attachment part to the rotating shaft 2 on the inner periphery and the attachment part for the seal member 8 on the outer periphery. The portion shown has window holes 7b formed at equal intervals, leaving a spring piece portion 7a extending in the radial direction with respect to the rotation center axis O.

When such an elastic member 7 is used, the centrifugal force acting on the seal member 7 causes the elastic member 7 to bend the spring piece portion 7a by 1.
By moving the lip 14 away from the frusto-conical sealing surface 11, that is, in the direction of the rotation center axis, the sliding contact force of the lip 14 is reduced.
Deflection occurs due to the action of centrifugal force at a lower rotational speed than in the case where the window hole 7b is not formed.

In this case, it is preferable to form the spring piece portion 7a into a flat plate shape.

Furthermore, when an appropriate number of weights 9 are disposed inside the seal member 8, the centrifugal force acting on the seal member 8 is increased by the weight of the weights 9, so that the pressing force of the lip 14 against the sealing surface 11 is reduced. When the pressing force by the elastic member 7 is strengthened, embedding the weight 9 is extremely advantageous when it is desired to reduce the pressing force when the rotary shaft 2 rotates at high speed or to separate the lip 14 from the sealing surface 11.

In this case, care must be taken when arranging the weight 9 so as not to generate unbalanced force due to rotation.

This invention forms a bottomed groove in the fixed member with two sealing surfaces formed on a cylindrical surface and a truncated conical surface with the rotation center axis of the rotating member as the center axis, and fixes the rotation member with the rotation center axis as the center axis. A rotating member is formed by using a grooved plate-like elastic member having elasticity and flexibility, which is inclined in the same direction as the truncated conical sealing surface formed on the member, and has elasticity and flexibility, for example, formed in a truncated conical shape. The sealing member is pressed by the elasticity of the elastic member, and the sealing member has a sealing surface formed in a cylindrical surface with the center axis of rotation as the center axis, and a lip contacting the truncated conical sealing surface formed on the fixed member. Therefore, while the rotating member is stopped, the gap between the sealing member inserted into the bottomed groove of the fixed member and the fixed member is connected to the frustoconical sealing surface of the lip of the sealing member. The liquid leakage between the stationary member and the rotating member is sealed, and even if the rotating member starts rotating, the lip remains in pressure contact with the sealing surface during low-speed rotation, so there is no liquid leakage. .

Further, as the rotation of the rotating member gradually increases in speed, centrifugal force due to rotation around the rotation center axis acts on the sealing member,
Since the elastic member is inclined in the same direction as the truncated conical sealing surface with respect to the rotational center axis (for example, because it is formed in a substantially truncated conical shape with the rotational center axis as the central axis) , the centrifugal force causes the elastic member to deflect in a direction that brings it closer to a plane perpendicular to the rotational center axis, and a force that moves the sealing member in the direction of the rotational center axis acts on the sealing member, causing the sealing member to move toward the truncated cone of the fixed member. Since the force of pressing against the planar sealing surface is reduced, as the rotating member rotates at higher speeds, the resistance due to the frictional sliding contact between the sealing member and the sealing surface of the fixed member gradually decreases.

When the rotational speed of the rotating member reaches a predetermined speed, the lip of the sealing member separates from the truncated conical sealing surface of the stationary member due to centrifugal force, and the resistance due to frictional sliding contact completely disappears.

- In the old book design, there is a labyrinth on either or both of the two sealing surfaces, the cylindrical sealing surface of the fixing member and the cylindrical sealing surface of the sealing member, which face each other with a small gap. Since a labyrinth seal is formed between the two seal surfaces by cutting a groove, the labyrinth seal has a high sealing effect when the relative surface velocity is high, thereby preventing liquid leakage due to sliding contact between the lips. Even if the seal deteriorates or disappears, the labyrinth seal seals off liquid leakage between the stationary member and the rotating member.

As described above, the present invention provides a device for sealing liquid leakage between a rotating member and a stationary member facing the rotating member, in which the sealing member rotates together with the rotating member when the rotating member is stopped or rotating at low speed. The lip of the elastic member is pressed against the sealing surface of the fixed member to function as a contact sealing device, and as the rotation of the rotating member gradually increases in speed, the centrifugal force is used to stop the rotation of the rotating member. As the speed increases, the pressure relief force on the sealing surface of the lip is lowered to reduce frictional resistance, and when the rotational speed of the rotating member exceeds a predetermined value, the contact between the lip and the sealing surface is released, creating a labyrinth seal. It functions as a non-contact type sealing device, and is an extremely useful device with a simple structure and high effectiveness.

In the present invention, when a weight is disposed on the sealing member, the presence of the weight makes the centrifugal force acting on the sealing member even stronger when the rotating member rotates at high speed, and the elastic member is made to have a good sag. , reduces the pressure contact force of the lip to the sealing surface,
Alternatively, it is extremely effective to separate the lip from the seal surface and reduce frictional resistance, and the labyrinth groove carved in each cylindrical seal surface, which is the opposing surface between the rotating member and the stationary member, is spirally shaped. When the seal is formed in a shape, a pumping action is produced in which the liquid leaking onto the sealing surface is returned to the original chamber through the spiral labyrinth groove, so that liquid leakage can be more completely sealed.

[Brief explanation of the drawing]

The drawings are cross-sectional views of an embodiment of the present invention taken along a plane including the central axis of rotation of the rotating member. They are shown below. FIG. 3 is a front view of the elastic member. In the figure, 1 is a fixed member, 2 is a rotating member, I is an elastic member, 8 is a sealing member, and 9
13 is a weight, 13 is a ring member, 11 is a truncated conical sealing surface, 10°15.19 is a cylindrical sealing surface, 16,
Reference numerals 17 and 18 indicate labyrinth grooves, respectively.

Claims (3)

[Scope of utility model registration request] (1) In a device for sealing liquid leakage between a rotating member and a stationary member facing the rotating member, two surfaces are formed on a cylindrical surface and a truncated conical surface with the central axis of rotation of the rotating member as the central axis. A bottomed groove formed by opposing seal surfaces is formed in the fixing member, and the elastic and flexible groove is inclined in the same direction as the truncated conical seal surface formed in the fixing member with respect to the rotation center axis. A thin plate-like elastic member having a flexible surface is fixed to the rotating member by one end edge thereof, and is opposed to a cylindrical sealing surface formed on the fixed member with a slight gap around the rotational center axis as the central axis. A sealing member having a cylindrical sealing surface and a lip that abuts a frustoconical sealing surface formed on the fixing member is fixed to the free end edge of the elastic member. The lip is brought into pressure contact with the fixing member by elasticity, and a labyrinth seal is formed by a labyrinth groove carved in one or both of the inclined cylindrical seal surfaces formed on each of the seal member and the fixing member and facing each other. A sealing device comprising: a centrifugal force acting on the sealing member during rotation of a rotary member to reduce the pressing force of the lip of the sealing member against the ring member by the elastic member. (2) A weight is embedded in a suitable position in the sealing member, and when the rotating member rotates, centrifugal force generated by the rotation of the weight around the rotation center axis causes the lip of the sealing member to be moved by the elastic member. The sealing device according to claim 10, characterized in that the pressure force applied to the ring member is reduced. (3) The labyrinth grooves of the sealing member and the ring member are formed in a spiral shape, and the relative rotation of both members provides a pumping action. The sealing device described.