JP6655365B2 - Seal member - Google Patents

Description

  The present invention relates to a seal structure, and more particularly to a structure of a seal member used for a sliding gap between a rod (piston rod) and a cylinder in a hydraulic and pneumatic device or the like.

  For example, in a sliding gap between a cylinder and a rod (piston rod) in a hydraulic device, leakage of hydraulic oil introduced into the oil chamber (leakage of hydraulic oil from a high pressure side to a low pressure side) is prevented, and In order to smoothly perform the reciprocating motion, a seal structure in which a seal member is fitted into a seal groove provided in a cylinder is employed. Such a sealing structure is disclosed in Japanese Patent Application Laid-Open No. 2005-337440 (Patent Document 1), Japanese Patent Application Laid-Open No. 2014-214768 (Patent Document 2), and the like.

JP 2005-337440 A JP 2014-21469A

  2. Description of the Related Art In recent years, seal members have been improved daily to further enhance the sealing performance of a seal structure.

  The present invention has been made to solve the above-described problem, and an object of the present invention is to provide a seal member that can further enhance the sealing performance of a seal structure.

  In the seal member according to the present invention, the seal groove is provided in a sliding gap between the cylinder and the rod in the hydraulic and pneumatic device, which is divided into a high pressure side and a low pressure side, and is provided annularly along a circumferential direction of an outer peripheral surface of the rod. The seal member is housed in the inside of the cylinder and closes a sliding gap between the cylinder and the rod, and has the following configuration.

A heel portion located on the low pressure side, and a lip portion located on the high pressure side, wherein the heel portion has a first side surface located on the rod side, a second side surface located opposite the first side surface, and a third side located lower pressure side, the lip portion includes a first lip extending toward the rod side, and has a second lip extending toward the opposite to the rod side, A curved surface and an inclined surface are provided in a region where the first side surface and the third side surface of the heel portion intersect, and the curved surface is provided so as to be in contact with the first side surface and the inclined surface. The slope is provided so as to intersect the third side surface.

  In another embodiment, a projection length of the curved surface and the slope on the third side surface is 0.3 mm or more and 2 mm or less, a radius of the curved surface is 2 mm or more and 15 mm or less, and The inclination angle with respect to the third side surface is 30 ° to 80 °.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the sealing structure which enables the sealing performance by a sealing structure to be improved more.

It is sectional drawing which shows the seal structure employ | adopted in the hydraulic equipment of embodiment. It is a perspective view showing the structure of the 1st seal member of an embodiment. FIG. 3 is a sectional view taken along line III in FIG. 2. FIG. 4 is a partially enlarged schematic diagram showing a sealed state of a first seal member in the embodiment. (A) is a diagram showing a seal pressure state of the first seal member at the time of mounting according to the embodiment, and (B) is a relationship between a contact width and a contact surface pressure of the first seal member at the time of mounting according to the embodiment. FIG. (A) is a diagram showing the state of the seal pressure of the first seal member under a pressure load according to the embodiment, and (B) is a relationship between the contact width and the contact surface pressure of the first seal member under a pressure load according to the embodiment. FIG. It is sectional drawing which shows the structure of the 1st seal member in related technology. It is the elements on larger scale which show the sealing state of the 1st sealing member in related technology. (A) is a figure which shows the seal pressure state in the 1st sealing member at the time of installation of a related art, (B) is a figure which shows the relationship between the contact width and contact surface pressure at the time of installation of a related art. (A) is a figure which shows the seal pressure state in the 1st sealing member at the time of the pressure load of a related art, (B) is a figure which shows the relationship between the contact width and the contact surface pressure at the time of the pressure load of a related art. FIG. 7 is a diagram illustrating a relationship between a sliding distance and a leakage amount according to the embodiment and related technologies. It is sectional drawing which shows the modification of the 1st sealing member of embodiment. It is sectional drawing which shows the other modification of the 1st seal member of embodiment. (A) is a diagram showing a seal pressure state of (R = 15, θ = 80 °, a = 0.3) under the pressure load of the first embodiment, and (B) is a diagram showing the seal pressure state of the first embodiment. FIG. 4 is a diagram showing a relationship between a contact width and a contact surface pressure in FIG. (A) is a diagram showing the sealing pressure state of (R = 2, θ = 30 °, a = 2) under the pressure load of the second embodiment, and (B) is the contact pressure under the pressure load of the second embodiment. It is a figure showing the relation between width and contact surface pressure. (A) is a diagram showing the sealing pressure state of (R = 0.5, θ = 30 °, a = 2) under the pressure load of the third embodiment, and (B) is the diagram under the pressure load of the third embodiment. FIG. 4 is a diagram showing a relationship between a contact width and a contact surface pressure in FIG.

  A seal member according to an embodiment of the present invention and a seal structure using the seal member will be described below with reference to the drawings. In the embodiments described below, when referring to the number, the amount, and the like, the scope of the present invention is not necessarily limited to the number, the amount, and the like, unless otherwise specified. The same components and corresponding components are denoted by the same reference numerals, and duplicate description may not be repeated. In the following, a hydraulic cylinder is given as an example of the hydraulic and pneumatic device, but the present invention is not limited to the hydraulic cylinder and can be widely applied to hydraulic and pneumatic devices.

(Seal structure)
With reference to FIG. 1, a seal structure according to the present embodiment will be described. FIG. 1 is a cross-sectional view illustrating a seal structure employed in the hydraulic cylinder according to the embodiment. In FIG. 1, a cylinder 1 and a rod (piston rod) 2 are shown by broken lines for convenience of explanation. The seal structure shown in FIG. 1 is deformed due to the pressure contact with the rod 2 and the reciprocating movement of the rod 2 (vertical direction in FIG. 1), but in order to clearly understand the seal structure, pressure is applied to the seal structure. FIG.

  An annular first seal groove 10 </ b> G is provided along the circumferential direction of the outer peripheral surface of the rod 2. The first seal member 10 that closes the sliding gap between the cylinder 1 and the rod 2 is accommodated in the first seal groove 10G.

Provided annularly in the circumferential direction of the outer peripheral surface of the rod 2, the low pressure side, a second sealing groove 20G is provided than the first seal groove 10G. In the drawing, a high-pressure hydraulic chamber is provided on the upper side. The second seal groove 20 </ b> G houses a second seal member 20 that closes a sliding gap between the cylinder 1 and the rod 2.

(First seal member 10)
The first seal member 10 in the present embodiment will be described with reference to FIGS. FIG. 2 is a perspective view showing the structure of the first seal member 10, and FIG. 3 is a sectional view taken along line III in FIG.

  The first seal member 10 has an annular shape as a whole, and is integrally formed of synthetic resin such as urethane resin, natural rubber, synthetic rubber, or fluoro rubber. The first seal member 10 has a substantially U-shaped cross section having an open side on the high pressure side.

More specifically, in the cross-sectional view shown in FIG. 3, a heel portion 10h located on the low pressure side and a lip portion 10r located on the high pressure side are provided. Heel 10h includes first side surface 101 positioned on the rod 2 side, a second side 102 opposite position to the first side surface 101 and, a third side surface 103 positioned on the low pressure side.

The lip 10r includes a first lip 10b extending toward the rod 2 and a second lip 10c extending toward the side opposite to the rod 2. The first lip portion 10b and the second lip portion 10c form a substantially U shape.

  Further, a curved surface 110 and a slope 120 are provided in a region where the first side surface 101 and the third side surface 103 of the heel portion 10h intersect, which is the low pressure side on the rod 2 side as viewed from the heel portion 10h. . The curved surface 110 is provided so as to be in contact with the first side surface 101 and the slope 120, and the slope 120 is provided so as to intersect with the third side surface 103.

  When the projection length of the curved surface 110 and the inclined surface 120 on the third side surface 103 is “a”, the radius of the curved surface 110 is “R”, and the inclination angle of the inclined surface 120 with respect to the third side surface 103 is “θ”. In order to obtain better sealing performance with respect to the rod 2 in the first sealing member 10, the projection length “a” is 0.3 mm or more and 2 mm or less, the radius “R” of the curved surface 110 is 2 mm or more and 15 mm or less, The inclination angle “θ” of the slope 120 with respect to the third side surface 103 is preferably 30 ° to 80 °. This will be described in an embodiment described later.

  Referring again to FIG. 1, when viewed from the first seal member 10, when the rod 2 moves from the low-pressure side to the high-pressure side, it is called a “pulling step”, and the rod 2 is moved to the high-pressure side. The movement from to the low pressure side is called a “push process”.

  The sealing state of the first seal member 10 will be described with reference to FIGS. FIG. 4 is a partially enlarged schematic diagram showing a sealing state in the “pulling step”, FIG. 5A is a diagram showing a sealing pressure state of the first seal member 10 at the time of mounting, and FIG. 6A is a diagram showing the relationship between the contact width and the contact surface pressure of the first seal member 10 at the time, and FIG. 6A is a diagram showing the seal pressure state of the first seal member 10 at the time of applying a pressure, and FIG. FIG. 3 is a diagram showing a relationship between a contact width of the first seal member 10 and a contact surface pressure at the time of applying a pressure. 5 (A) and FIG. 6 (A), P1 to P10 indicate the distribution of the internal pressure, and indicate that the internal pressure decreases from P1 to P10.

  As shown in FIGS. 4 and 5A, the first lip portion 10 b has a form expanding toward the rod 2, and the first side surface 101 and the third side surface 103 of the heel portion 10 h of the first seal member 10. The heel portion 10h is in a non-contact state with the rod 2 even at the time of mounting, by providing the curved surface 110 and the inclined surface 120 in the region where It can be easily returned to the inside.

  As is clear from the diagram showing the relationship between the contact width and the contact surface pressure of the first seal member 10 at the time of mounting in FIG. 5B, the region where the first side surface 101 and the third side surface 103 of the heel portion 10h intersect. Since no contact is made with the rod 2, no peak surface pressure is generated in the region R1. On the other hand, the first lip portion 10b and the second lip portion 10c are sandwiched between the first seal groove 10G and the rod 2 and greatly deformed. (Area shown), a peak surface pressure due to contact occurs.

  Next, even at the time of the pressure load in FIG. 6, by providing the curved surface 110 and the inclined surface 120 in the region where the first side surface 101 and the third side surface 103 of the heel portion 10h intersect, the peak surface pressure is applied to the region R1. The contact surface pressure can maintain a smooth state even if the contact width moves without occurrence of the contact width. As a result, the resistance of the oil to the inside of the cylinder 1 can be returned to a low level, and the sealing structure using the first seal member 10 can improve the oil suction characteristics and further enhance the sealing performance.

  On the other hand, FIG. 7 shows a cross-sectional view of the first seal member 10X in the related art. FIG. 3 is a diagram corresponding to a cross section taken along line III-III in FIG. 2. The shapes of the first lip portion 10b and the second lip portion 10c of the lip portion 10r are the same as those of the first seal member 10 of the present embodiment. In the first seal member 10X, only the slope 150 is provided in a region where the first side surface 101 and the third side surface 103 intersect, and no curved surface is provided.

  With reference to FIGS. 8 to 10, the sealing state of the first sealing member 10X of the related art will be described. FIG. 8 is a partially enlarged schematic diagram showing a sealing state in the “pulling step”, FIG. 9A is a diagram showing a sealing pressure state of the first seal member 10X at the time of mounting, and FIG. FIG. 10A is a diagram showing a relationship between a contact width and a contact surface pressure of the first seal member 10X at the time, and FIG. 10B is a diagram showing a seal pressure state of the first seal member 10X under a pressure load. FIG. 6 is a diagram showing a relationship between a contact width of the first seal member 10X and a contact surface pressure at the time of applying a pressure. 9 (A) and 10 (A), P1 to P10 indicate the distribution of the internal pressure, and indicate that the internal pressure decreases from P1 to P10.

  As shown in FIGS. 8 and 9A, the first seal member 10X has no curved surface provided on the heel portion 10h of the first seal member 10X, but has only the inclined surface 150. As a result, at the time of mounting, the heel portion 10h comes into contact with the rod 2, and a peak surface pressure is formed in the region R3 as shown in FIG. 9B. Further, even at the time of the pressure load in FIG. 10, in the region where the first side surface 101 and the third side surface 103 of the heel portion 10h intersect, since only the slope 150 is present, a larger peak surface pressure is generated in the region R4. As a result, at the time of the pulling process, the oil suction characteristics are poor, which is one of the causes of oil leakage.

  FIG. 11 compares and describes the amount of leakage between the first seal member 10 of the embodiment and the first seal member 10X of the related art. FIG. 11 is a diagram illustrating a relationship between a sliding distance and a leakage amount between the first seal member 10 of the embodiment and the first seal member 10X of the related art.

  Both the first seal member 10 and the first seal member 10X are made of a synthetic resin such as urethane resin (hardness durometer A90, tensile strength Mpa 44.0, elongation 500%, compression set 40%, compression set test conditions). 8) (80 ° C-70h): Nippon Valqua Industry Co., Ltd., product number R5590)) was used.

  The first seal member 10 has R = 2 mm, θ = 60 °, and a = 0.6 mm. The first seal member 10X has no curved surface, and the slope 150 has R = 0 mm, θ = 45 °, and a = 0.5 mm (so-called C surface = 0.5 mm).

  In each of the measurements, only the first seal member was mounted, and the amount of oil leakage from the cylinder 1 was measured. The result is shown in FIG. It was confirmed that the first seal member 10 in the present embodiment had better sealing performance than the first seal member 10X in the related art.

(Example)
FIG. 12 and FIG. 13 show a structure of a modified example of the first seal member 10 in the present embodiment. FIG. 12 shows the shape of the first seal member 10A provided with a relatively large “a”, and FIG. 13 shows the shape of the first seal member 10B provided with a relatively large “θ”.

  Further, FIGS. 14 to 16 show the relationship between the contact width and the contact surface pressure at the time of applying a pressure as specific Examples 1 to 3. FIG. The first seal member 10 in the first embodiment has a shape of R = 15, θ = 80 °, a = 0.3, and the first seal member 10 in the second embodiment has a shape of R = 2, θ = 30 °. , A = 2, and the first seal member 10 in the third embodiment has a shape of R = 0.5, θ = 30 °, and a = 2. In (A) of each drawing, P1 to P10 indicate the distribution of the internal pressure, and indicate that the internal pressure decreases from P1 to P10.

  In the case of Example 1 shown in FIG. 14, no peak surface pressure was generated over the entire contact width, and good surface pressure was shown. Therefore, it was confirmed that the device had excellent sealing performance. did it.

  In the case of Example 2 shown in FIG. 15, no peak surface pressure is generated over the entire contact width and a better surface pressure is shown as compared with Example 1 described above. It was confirmed that it had performance.

  In the case of the third embodiment shown in FIG. 16, a fine peak surface pressure is generated in a region where the contact width is about 1 mm as compared with the first embodiment, so that the third embodiment is better than the first embodiment. However, since it is better than the related art shown in FIG. 10, it was confirmed that it had good sealing performance as a whole.

  According to the above embodiment, a curved surface 110 and a slope 120 are provided in a region where the first side surface 101 and the third side surface 103 of the heel portion 10h intersect, and the curved surface 110 is formed by the first side surface and the slope 120 , And the slope 120 is provided so as to intersect the third side surface 103. Thereby, the first seal member in the present embodiment has good sealing performance.

  Further, the projection length “a” of the curved surface 110 and the inclined surface 120 on the third side surface 103 is set to 0.3 mm or more and 2 mm or less, and the radius “R” of the curved surface 110 is set to 2 mm or more and 15 mm or less. By setting the inclination angle “θ” with respect to the third side surface 103 from 30 ° to 80 °, it is possible to obtain more preferable sealing performance.

  Although the embodiments and examples have been described above, the embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

Reference Signs List 1 cylinder, 2 rod, 10, 10A, 10B first seal member, 10G first seal groove, 10h heel portion, 10r lip portion, 20 second seal member, 20G second seal groove, 101 first side surface, 102 second Side, 103 third side, 10b first lip, 10c second lip, 110 curved surface, 120 ramp.

Claims (1)

In the sliding gap between the cylinder and the rod in the hydraulic and pneumatic device, the cylinder is partitioned into a high pressure side and a low pressure side, and is housed in a seal groove provided in an annular shape along the circumferential direction of the outer peripheral surface of the rod, and A seal member for closing a sliding gap with the rod,
A heel part located on the low pressure side,
Including a lip portion located on the high pressure side,
The heel part,
First side surface located on the rod side, a second side opposite position to said first side surface, and has a third side located lower pressure side,
The lip portion,
A first lip extending toward the rod, and a second lip extending toward the opposite side to the rod;
A curved surface and a slope are provided in a region where the first side surface and the third side surface of the heel portion intersect,
The curved surface is provided to be in contact with the first side surface and the inclined surface,
Wherein the beveled surface is provided et is to intersect the third side,
The projection length of the curved surface and the slope onto the third side surface is 0.3 mm or more and 2 mm or less,
The radius of the curved surface is 2 mm or more and 15 mm or less,
A sealing member , wherein an inclination angle of the inclined surface with respect to the third side surface is 30 ° to 80 ° .

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