JP5325674B2 - Sealing device - Google Patents

Description

  The present invention relates to a sealing device that prevents intrusion of water, dust and the like.

  For example, a sealing device using an annular V-shaped sealing member is conventionally known as a waterproof / dustproof measure (see, for example, Patent Document 1).

  This type of sealing device is used, for example, in an electric tool having a rotating shaft. As shown in FIG. 3A, when the rotary shaft 50 is stationary or rotating at a low speed, the seal surface 51 of the bearing cap 53 is substantially V-shaped in cross section and the lip 56 of the annular seal member 55 is sealed. In addition, water and dust are prevented from entering the peripheral surface of the rotating shaft and the bearing. As shown in FIG. 3B, when the rotary shaft 50 rotates at a high speed, the lip 56 of the seal member 55 is elastically deformed by the centrifugal force and stands up and moves away from the seal surface 51 of the bearing cap 53. In addition, since the water and dust when the rotating shaft 50 is rotating at high speed move to the outer periphery of the sealing member 55 by centrifugal force, the sealing performance is maintained. Further, since the lip 56 is separated from the seal surface 51 when the rotary shaft 50 is rotating at a high speed, heat generation and wear of the lip 56 due to sliding with the seal surface 51 are prevented.

JP 2005-249044 A

  The allowable rotational speed of the rotary shaft is clearly indicated on the seal member. When the rotational speed exceeds the allowable rotational speed, the seal member 55 is elastically deformed by its centrifugal force as shown in FIG. The lip 51 may elastically deform and come into contact with other members (such as the bearing cap 53) and be damaged. Therefore, the seal member cannot be used beyond the allowable number of rotations.

  Therefore, an object of the present invention is to provide a seal device that can be used even when the allowable rotational speed of the annular seal member is simply exceeded.

In order to solve the above-mentioned problem, the sealing device according to claim 1 surrounds the rotating shaft (5) and the outer periphery of the rotating shaft, and supports the rotating shaft rotatably via a bearing (7). A member (8), and an annular sealing member (20) disposed between the rotating shaft and the supporting member and having elasticity, and the sealing member is a base (21) fixed to the rotating shaft When extending the diagonal outer peripheral side from said substrate, in contact with said support member includes a lip (22) forming a groove (25) in the base body and cooperates, in said groove, said rotary shaft An annular member (30) is provided that regulates the range of movement of the lip that is elastically deformed by centrifugal force due to the rotation of the lip and separates from the support member .

  According to the present invention, excessive deformation of the seal member is easily limited, and the seal member is less likely to be elastically deformed excessively by centrifugal force when the rotating shaft rotates beyond the allowable rotation speed. The sealing function can be maintained even when used by rotating.

  The sealing device according to claim 2 is the sealing device according to claim 1, wherein the annular member has a higher elastic coefficient than the sealing member.

  According to the present invention, it is possible to reliably maintain the sealing function even when used with rotation exceeding the allowable rotational speed.

  The sealing device according to a third aspect is the sealing device according to the first or second aspect, wherein the sealing device has a protruding portion protruding in an outer peripheral direction in front of the rotating shaft, and the sealing member is , It is characterized by being arranged between the projection and the support member.

  According to this invention, it becomes difficult for water and dust to enter the bearing directly from the outside.

  According to the present invention, a special member can be used at a rotational speed exceeding the allowable rotational speed of the annular seal member in a small space without being fixed.

It is a partial cross section block diagram of the front-end | tip part of an electric tool. It is an enlarged view of the A part of FIG. It is the elements on larger scale which show an example of the conventional sealing apparatus using an annular sealing member.

  The best mode for carrying out the present application will be described below with reference to the drawings. Embodiment described below applies this application to the electric tool T which has a rotating shaft, for example. In addition, in the following description, since the general structure which exists conventionally is applied about the structure of the electric tool T, the detailed description shall be abbreviate | omitted.

  FIG. 1 is a partial cross-sectional configuration diagram of a tip portion of an electric power tool, and FIG. 2 is an enlarged view of a portion A in FIG.

  As shown in FIG. 1, the electric power tool T includes a housing 2 (supporting member of the present application) that surrounds the outer periphery of the rotating shaft 5, and the housing 2 includes a constituent member in which the rotating shaft 5 includes a bearing 7. It is attached via a rotation. For example, a chuck 10 to which a tool for performing screw tightening, drilling or the like is detachably attached is provided at the tip of the rotating shaft 5. The chuck 10 has a tool holding hole in which a tool is inserted and held at the center, and a fixing / releasing tool for detachably fixing or releasing the tool to the chuck 10 can be inserted into the outer peripheral surface thereof. A hole 10a is formed.

  Although not shown, a rotation transmission mechanism unit including a drive unit such as a motor and a reduction gear to which the output of the motor is transmitted is incorporated in the rear of the housing 2, and the output of the motor is transmitted via the rotation transmission mechanism unit. A rotational driving force is transmitted to the rotating shaft 5.

  Two bearings 7 are provided in series on the front peripheral surface of the rotating shaft, and the peripheral surface is held by the housing 2. The housing 2 has an opening for receiving the rotary shaft 5 and the bearing 7 in the front, and an annular bearing cap for pressing the side surface of the bearing 7 to hold the bearing 7 in the opening. 8 is mounted. The bearing cap 8 also functions as a part of the housing 2.

  A projecting portion 5a projecting in the outer peripheral direction is formed at the tip of the rotating shaft 5. The projecting portion 5a prevents water and dust from entering the bearing 7 directly.

  Further, an annular seal member 20 having a V-shaped cross section is disposed between the protruding portion 5a and the bearing cap 8. The seal member 20 allows the bearing 7 and the like to be externally provided through a gap. Intrusion of water and dust is prevented.

  As shown in FIGS. 1 and 2, the seal member 20 includes a base body 21 that is fitted and fixed to the rear end face of the protruding portion 5 a, and extends from the base body 21 to the outer peripheral side in the oblique direction. A lip 22 capable of contacting the sealing surface 8a) and forming a groove 25 in cooperation with the base 21;

  The seal member 20 has a permissible rotational speed. When the rotary shaft 5 stops or rotates at a low speed in the permissible rotational range, the seal member 20 contacts the bearing cap 8 to keep the sealing performance by blocking the gap. At the time of high speed rotation, the distal end portion of the lip 22 is separated from the seal surface 8a of the bearing cap 8 due to centrifugal force and stands on the protruding portion 5a side. As described above, when the rotary shaft 5 rotates at high speed, the lip 22 is separated from the seal surface 8a of the bearing cap 8, and thus heat generation of the lip 22 due to contact with the bearing cap 8 is prevented. Further, when the rotary shaft 5 rotates at high speed, water and dust entering from the outside move to the outer peripheral edge of the lip 22 by centrifugal force, so that the sealing performance in the gap formed between the protruding portion 5a and the bearing cap 8 is improved. Kept.

  The groove 25 of the seal member 20 is provided with an annular member 30 that restricts the movement range of the lip 22 according to the number of rotations of the rotary shaft 5. As the annular member 30, one having an elastic coefficient higher than that of the seal member 20 (not easily deformed) is used. Moreover, as a material, although the thing made from resin is used suitably, it may be made from a metal or ceramics.

  Here, in order to compare the sealing performance of the conventional sealing member and the sealing member 20 provided with the annular member 30 of the present embodiment, the test was performed by setting the rotational speed of the rotary shaft between 0 and 20,000 rpm. As a result, the conventional seal member is abnormally heated and damaged due to contact with other members as a result of deformation of the lip and the seal member due to centrifugal force. However, in the seal member 20 provided with the annular member 30, No trouble occurred.

  As a result of having the above-described configuration, the sealing device of the present embodiment is configured such that the lip 22 of the seal member 20 is in contact with the seal surface 8a of the bearing cap 8 when the rotary shaft 5 is stationary or at a low rotation, so that the gap is blocked. This keeps the sealing performance and prevents water and dust from entering from the outside. On the other hand, when the rotary shaft 5 rotates at a high speed, the lip 22 of the seal member 20 is separated from the seal surface 8a of the bearing cap 8, but water and dust that enter from the outside due to centrifugal force are directed toward the outer peripheral side in the radial direction of the seal member 20. The peripheral edge of the seal member 20 is moved to prevent the water and dust from entering, and the lip 22 is prevented from being heated and worn by the contact between the lip 22 and the seal surface 8 a of the bearing cap 8.

  Furthermore, since the annular member 30 is provided in the groove 25 of the seal member 20 even at a high speed exceeding the allowable rotation speed of the seal member 20, the rigidity of the groove 25 portion of the seal member 20 is increased and the lip 22 is increased. To prevent the spread of more than necessary. Thereby, it is possible to avoid contact with other members such as the bearing cap 8 caused by an increase in centrifugal force and elastic deformation of the seal member 20 and the lip 22. Moreover, damage to the lip 22 can be prevented by avoiding contact with other members.

  In addition, this embodiment is one form and is not limited to this form. For example, the sealing device of the present embodiment is not limited to the one that is applied to ensure the sealing property of the gap in the electric power tool, but includes a rotating shaft and can be applied to ensure the sealing property in a narrow region. it can.

T electric tool 2 housing 5 rotating shaft 8 bearing cap 20 seal member 21 base 22 lip 25 groove 30 annular member

Claims (3)

A rotation axis;
A support member that surrounds the outer periphery of the rotating shaft and supports the rotating shaft rotatably via a bearing;
An annular seal member disposed between the rotating shaft and the support member and having elasticity;
The sealing member is
A base fixed to the rotating shaft;
A lip extending obliquely outward from the base, contacting the support member, and forming a groove in cooperation with the base;
The sealing device according to claim 1, wherein the groove is provided with an annular member that restricts a moving range of the lip that is elastically deformed by a centrifugal force and moves away from the support member by rotation of the rotating shaft .   The sealing device according to claim 1, wherein the annular member has an elastic coefficient higher than that of the seal member. In front of the rotating shaft, it has a protruding portion protruding in the outer peripheral direction,
The seal device according to claim 1, wherein the seal member is disposed between the protruding portion and the support member.

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