JP4887718B2 - Sealing device - Google Patents

Description

  The present invention relates to a sealing device that relatively reciprocates and rotates and seals an annular gap between two members where eccentricity occurs. For example, a servo piston that controls the tilt angle of a power roller of a continuously variable transmission The present invention relates to a sealing device suitable for use in the above.

  Conventionally, a resin seal ring has been used as a seal member for sealing a gap between a servo piston, a servo piston body, and a control valve body in a continuously variable transmission (see Patent Document 1). FIG. 9 shows a sectional view of the servo piston portion of the continuously variable transmission.

The servo piston 9 fitted in the servo piston body 13 moves in the direction of the axis O ₃ in response to a pressure command from an oil passage provided in the control valve body 14, thereby moving the trunnion 4 in the direction of the axis O _3. Stroke to. At this time, due to the offset between the rotation axis O ₂ of the power roller and the rotation axis of the input / output cone disk, the power roller receives a swinging component from the input / output cone disk and tilts around the axis O ₃ , thereby changing the speed. The gear ratio of the machine changes. When the predetermined gear ratio is reached, the predetermined speed ratio is maintained by returning the trunnion 4 to the original stroke position via the servo piston 9 by gear ratio feedback control.

  As described above, in shifting the transmission, the servo piston 9 performs two types of movements, reciprocating and rotating (tilting). Therefore, the seals 15 to 19 that seal the gaps between the servo piston 9 and the servo piston body 13 and the control valve body 14 are required to maintain the sealing performance even when reciprocating or rotating. The In particular, in the case of a continuously variable transmission, since it is necessary to accurately control the stroke position and the tilt angle due to the mechanism, a high level of low leakage is required.

Further, the trunnion 4 supporting the power roller rotating around the axis O ₃ is bent and deformed between the connection points 5 and 6 with the links 7 and 8 by the transmission force F2, and the servo piston 9 is caused by this. Tilt. Therefore, in Patent Document 1, the servo piston 9, the servo piston body 13, and the control valve body 14 interfere with each other by increasing the gap between the servo piston 9 and the hole wall that guides it as the distance from the spherical joint 6 increases. To prevent it.

In this case, since the servo piston 9 is greatly decentered with respect to the servo piston body 13 and the control valve body 14, a seal member capable of maintaining the sealing performance even when such decentering occurs is required.
JP 07-217716 A Japanese Patent Laid-Open No. 11-248003 JP 2002-285141 A Japanese Utility Model Publication No. 62-069074

  However, when a seal ring as shown in FIG. 10 is used, when the hydraulic pressure direction changes, leakage occurs with the movement of the seal ring 100 (in FIG. 10, the hydraulic pressure is moved to the right in the figure). Indicates when to switch).

  As a seal suitable for reciprocating motion, a combination seal composed of a rubber-like elastic ring 101 and a resin ring 102 as shown in FIG. 11 has been conventionally known (see Patent Documents 2 and 3). If this also occurs, the rubber-like elastic ring 101 having low wear resistance may slide with the resin ring 102 (C in FIG. 11). There is a risk that it may cause a decrease in the quality. In particular, when a reciprocating motion and a rotation frequently occur like a servo piston, it is difficult to apply a combination seal.

  In the case where eccentricity occurs, if the seal member does not follow eccentricity, the sealing fluid may leak from the gap to the non-sealing fluid side when the servo piston 9 rotates. Therefore, in order to maintain the sealing performance even when eccentricity occurs, it is necessary to make a large allowance for crushing the rubber-like elastic ring 101 (FIG. 12a). However, if the crushing allowance is increased, the filling rate of the rubber-like elastic body ring 101 with respect to the groove at the time of mounting is increased, and the seal expansion force is increased (FIG. 12b). As a result, the friction generated when the seal slides increases, which hinders the operation of the device.

  The present invention has been made in order to solve the above-described problems of the prior art. The object of the present invention is to maintain the sealing performance even when both reciprocating motion and rotational motion occur, and the durability of the sealing member. It is an object of the present invention to provide a sealing device that can improve the above-described characteristics and to provide a sealing device that can obtain a stable sealing performance even when eccentricity occurs.

In order to achieve the above object, in the sealing device of the present invention,
A sealing device that seals an annular gap between a servo piston, a servo piston body, and a control valve body in a continuously variable transmission that relatively reciprocates and rotates, and that is eccentric .
A circumferential groove provided in one of the servo piston, servo piston body and control valve body ;
An elastic ring attached to the groove bottom side of the circumferential groove;
A resin ring mounted on the opening side of the circumferential groove and sliding on the other member;
A sealing device comprising:
The groove bottom surface of the circumferential groove has inclined surfaces on both sides that are inclined toward the opening side from the groove bottom center toward the groove sidewalls on both sides, respectively .
When eccentricity occurs between the servo piston , the servo piston body, and the control valve body , the elastic ring is inclined when the elastic ring and the resin ring are pressed against the low pressure side by the pressure from the high pressure side. It is characterized by moving to the low pressure side while raising the surface.

  As described above, when the eccentricity occurs, the elastic ring is pressed against the low pressure side while raising the inclined surface by the pressure from the high pressure side, so that the crushing margin is secured and the sealing performance can be maintained. Therefore, the crushing allowance can be ensured without increasing the filling rate, so that an excessive tightening force is not generated and the friction during sliding of the sealing device does not increase.

  As described above, by providing inclined surfaces on both sides in the axial direction, even when the hydraulic direction is switched by reciprocation, the sealing performance against eccentricity can be exhibited.

  As described above, according to the present invention, it is possible to maintain the sealing performance against both the reciprocating motion and the rotational motion, and to improve the durability of the sealing member. Further, even when eccentricity occurs, a stable seal with low friction can be obtained.

  The best mode for carrying out the present invention will be exemplarily described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. .

  The sealing device according to the first embodiment will be described with reference to FIGS. FIG. 1 is a schematic cross-sectional view showing a sealing device according to a first embodiment of the present invention. FIG. 2 is a schematic cross section showing a state when the sealing device according to the first embodiment of the present invention is mounted.

  The sealing device according to the first embodiment of the present invention is a portion where reciprocation, rotation, and eccentricity of a servo piston or the like of a continuously variable transmission as shown in FIG. 9, for example, requires high sealing performance. It is a sealing device that can be applied to any location.

  The sealing device is composed of an O-ring 1 and a resin ring 2 which are elastic rings, and seals an annular gap between the housing 3 and the shaft 4 inserted into the shaft hole of the housing 3. It is mounted in a circumferential groove 40 provided on the outer periphery of the shaft 4. The housing 3 and the shaft 4 relatively reciprocate and rotate, and may be eccentric.

  The O-ring 1 is a sealing member made of a rubber-like elastic body having a circular cross-sectional shape, and is attached to the groove bottom surface 41 side of the circumferential groove 40. The resin ring 2 is a sealing member made of a resin material having a substantially rectangular cross-sectional shape, and is attached to the opening side (housing 3 side) of the circumferential groove 40.

  The O-ring 1 and the resin ring 2 are mounted in the circumferential groove 40 in close contact with each other. Since the O-ring 1 has the interference allowance I with respect to the groove bottom surface 41, the O-ring 1 is sandwiched between the groove bottom surface 41 and the resin ring 2 and compressed in the radial direction when mounted. The elastic restoring force of the O-ring 1 acts as a pressing force that urges the resin ring 2 toward the housing 3.

  A taper 21 is provided on the sliding surface of the resin ring 2 with the housing 3. Therefore, the contact surface A between the resin ring 2 and the housing 3 is smaller than that when the taper 21 is not provided, and the sliding resistance between the resin ring 2 and the housing 3 is reduced. If it does so, the area of the contact surface B of the O-ring 1 and the resin ring 2 with respect to the contact surface A will increase relatively. As a result, since the sliding resistance generated on the contact surface B is relatively larger than the sliding resistance generated on the contact surface A, the O-ring 1 and the resin ring 2 are moved when the shaft 4 rotates relative to the housing 3. Can be prevented from sliding on each other. Therefore, wear of the sealing member due to sliding between the O-ring 1 and the resin ring 2 can be suppressed, and durability of the sealing device can be improved.

  In addition, since the combination seal can be suitably applied to a place where both the reciprocating motion and the rotational motion are generated as described above, a stable sealing performance can be obtained as compared with a conventionally used seal ring.

  In the present embodiment, the material of the O-ring 1 that is a rubber-like elastic body is preferably a material having good oil resistance, compression set, and mechanical strength, such as hydrogenated nitrile rubber (HNBR). Moreover, as a material of the resin ring 2, a low friction material is preferable, for example, tetrafluoroethylene resin (PTFE) is preferable. The housing 3 and the shaft 4 are made of metal.

  Here, with reference to FIG. 3, the relationship between the hydraulic pressure and the sliding resistance when the contact area (contact width in the axial direction) between the resin ring and the housing is changed will be described. FIG. 3 is a chart showing the relationship between hydraulic pressure and sliding resistance.

  As shown in the figure, it can be seen that the sliding resistance generated on the contact surface A decreases as the contact width of the contact surface A decreases.

  In the present embodiment, the taper 21 is provided in order to reduce the contact surface A, but it goes without saying that the same effect can be obtained by providing chamfering instead of providing the taper.

  With reference to FIG. 4, the sealing apparatus which concerns on a 2nd Example is demonstrated. FIG. 4 is a schematic cross-sectional view showing a sealing device according to a second embodiment of the present invention. In addition, the same number is attached | subjected about the structure similar to the said Example, the description is abbreviate | omitted, and only a different point is described below.

  In the present embodiment, an elastic ring 5 having a substantially rectangular cross-sectional shape is employed as a seal member mounted on the groove bottom 41 side, instead of the O-ring. A contact surface (outer peripheral surface) 51 of the elastic ring 5 with the resin ring 2 is a peripheral surface that extends to the full width dimension in the axial direction of the elastic ring 5. Therefore, compared with the case where an O-ring is used, since the contact surface B with the resin ring 2 becomes large, the sliding of seal members can be suppressed.

  With reference to FIG. 5, the sealing device according to the third embodiment will be described. FIG. 5 is a schematic cross-sectional view showing a sealing device according to a third embodiment of the present invention. In addition, the same number is attached | subjected about the structure similar to the said Example, the description is abbreviate | omitted, and only a different point is described below.

  In this embodiment, the contact surface (outer peripheral surface) 61 of the elastic ring 6 with the resin ring 2 is a peripheral surface that extends to the full width dimension in the axial direction of the elastic ring 6. Therefore, compared with the case where an O-ring is used, since the contact surface B with the resin ring 2 becomes large, the sliding of seal members can be suppressed.

  With reference to FIG. 6, the sealing apparatus which concerns on a 4th Example is demonstrated. FIG. 6 is a schematic cross-sectional view showing a sealing device according to a fourth embodiment of the present invention. In addition, the same number is attached | subjected about the structure similar to the said Example, the description is abbreviate | omitted, and only a different point is described below.

  In this embodiment, a circumferential lubricating groove 23 is provided on the sliding surface of the resin ring 2 with the housing 3. Therefore, the contact area A between the resin ring 2 and the housing 3 is reduced, and the sliding resistance between the resin ring 2 and the housing 3 is reduced by the lubricating oil acting on the lubricating groove 23. As a result, the sliding resistance between the O-ring 1 and the resin ring 2 becomes relatively large, so that the sliding between the O-ring 1 and the resin ring 2 during the rotational movement can be suppressed. Therefore, since the wear of the seal member due to the sliding between the O-ring 1 and the resin ring 2 can be suppressed, the durability of the sealing device can be improved.

  With reference to FIG. 7, a sealing device according to a fifth embodiment will be described. FIG. 7 is a schematic cross-sectional view showing a sealing device according to a fifth embodiment of the present invention. In addition, the same number is attached | subjected about the structure similar to the said Example, the description is abbreviate | omitted, and only a different point is described below.

  In the present embodiment, a plurality of lubrication grooves 23 provided on the contact surface of the resin ring 2 with the housing 3 in the fourth embodiment are provided. The effect of providing the lubricating groove 23 is the same as that of the fourth embodiment.

  With reference to FIG. 8, a sealing device according to a sixth embodiment will be described. FIG. 8A is a schematic cross-sectional view showing a sealing device according to a sixth embodiment of the present invention. FIG. 8B is a schematic cross section showing a state when the sealing device according to the sixth embodiment of the present invention is mounted. In addition, the same number is attached | subjected about the structure similar to the said Example, the description is abbreviate | omitted, and only a different point is described below.

  In the present embodiment, an inclined surface 43 is provided at the groove bottom of the circumferential groove 40 to which the O-ring 1 and the resin ring 2 are mounted. The inclined surface 43 is inclined toward the groove opening side from the groove bottom center toward the groove side wall 42. The O-ring 1 has a crushing margin I with respect to the inclined surface 43. When the housing 3 and the shaft 4 are eccentric, the O-ring 1 and the resin ring 2 are pressed against the low-pressure side under the pressure from the high-pressure side. It will move while climbing up. That is, when the O-ring 1 moves to the low pressure side due to the application of pressure, the O-ring 1 moves while generating a crushing margin. Therefore, even when eccentricity occurs, the sealing performance can be maintained, and a stable sealing performance can be obtained. Further, since the crushing margin can be secured without increasing the filling rate of the O-ring by the inclined surface 43, there is no occurrence of an excessive tension force due to the high filling rate. Accordingly, there is no increase in friction during sliding of the seal due to excessive tension, and there is no obstacle to the operation of the device.

  Furthermore, in this embodiment, an inclined surface 43 is provided for each of both side walls 42 of the circumferential groove 40. As described above, by providing the inclined surfaces 43 in both axial directions, the effect of maintaining the sealing performance by the inclined surfaces 43 against the eccentricity can be obtained even when the hydraulic direction is switched by reciprocation.

  Note that the inclination angle of the inclined surface 43 in this embodiment is preferably greater than 0 ° and not more than 45 °.

  In the above embodiment, the configuration in which the circumferential groove is provided on the shaft and slides on the housing has been described. However, the present invention is also suitably used for the configuration in which the circumferential groove is provided on the housing and slides on the shaft. Needless to say, you can.

FIG. 1 is a schematic cross-sectional view of a sealing device according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of a sealing device according to an embodiment of the present invention. FIG. 3 is a chart showing the relationship between hydraulic pressure and sliding resistance when the contact area is changed. FIG. 4 is a schematic cross-sectional view of a sealing device according to an embodiment of the present invention. FIG. 5 is a schematic cross-sectional view of a sealing device according to an embodiment of the present invention. FIG. 6 is a schematic cross-sectional view of a sealing device according to an embodiment of the present invention. FIG. 7 is a schematic cross-sectional view of a sealing device according to an embodiment of the present invention. FIG. 8 is a schematic cross-sectional view of a sealing device according to an embodiment of the present invention. FIG. 9 is a schematic cross-sectional view of a servo piston portion of a continuously variable transmission according to the prior art. FIG. 10 is a schematic cross-sectional view of a conventional sealing device. FIG. 11 is a schematic cross-sectional view of a conventional sealing device. FIG. 12 is a schematic cross-sectional view of a sealing device according to the prior art.

Explanation of symbols

1 O-ring 2 Resin ring 21 Taper 3 Housing 4 Shaft 40 Circumferential groove 43 Inclined surface

Claims (1)

A sealing device that seals an annular gap between a servo piston, a servo piston body, and a control valve body in a continuously variable transmission that relatively reciprocates and rotates, and that is eccentric .
A circumferential groove provided in one of the servo piston, servo piston body and control valve body ;
An elastic ring attached to the groove bottom side of the circumferential groove;
A resin ring mounted on the opening side of the circumferential groove and sliding on the other member;
A sealing device comprising:
Groove bottom of the circumferential groove is provided on both sides an inclined surface inclined respectively opening side from the groove bottom center toward both sides of the groove side wall,
When eccentricity occurs between the servo piston , the servo piston body, and the control valve body , the elastic ring is inclined when the elastic ring and the resin ring are pressed against the low pressure side by the pressure from the high pressure side. A sealing device that moves to a low-pressure side while raising a surface.

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