Seal structure for mating surface

Abstract

To provide a seal structure for a mating surface capable of maintaining sealability of the mating surface, even when foreign matter enters the mating surface (seal groove) and accumulates.SOLUTION: A seal structure for a mating surface comprises: a closed-loop first seal groove 31 formed on one surface side (a water pump 20 side) constituting a mating surface 30 between the water pump 20 and an oil pan upper 11 of an engine 10; a closed-loop second seal groove 32 formed outside the first seal groove 31 on the one surface side; an endless first rubber gasket 33 fitted into the first seal groove 31; an endless second rubber gasket 34 fitted into the second seal groove 32; and a cleaning fluid storage part 35 formed concavely between the first seal groove 31 and the second seal groove 32 on the one surface side and along the first seal groove 31 and the second seal groove 32, and stores cleaning fluid.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a sealing structure for mating surfaces. [Background technology]

[0002] For example, Patent Document 1 discloses a configuration in which a water pump is screwed to the side of an engine with multiple bolts. The mating surfaces of the engine (crankcase) and the water pump (water pump cover) are liquid-tightly sealed (sealed) to prevent the coolant from leaking to the outside, for example, by a rubber gasket (O-ring) fitted into a seal groove formed in the mating surfaces. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-88949 Summary of the Invention [Problem to be solved by the invention]

[0004] However, if foreign matter (such as calcium chloride or sodium chloride used as an ice-melting agent) gets into and accumulates (crystals grow) around the seal groove of the mating surface (particularly around the rubber gasket fitted into the seal groove), a gap may form between the mating surfaces, causing poor sealing and possibly leading to coolant leakage.

[0005] The present invention has been made to solve the above problems, and aims to provide a sealing structure for mating surfaces that can maintain the sealing properties of the mating surfaces even if foreign matter enters and accumulates on the mating surfaces (seal grooves). [Means for solving the problem]

[0006] A sealing structure for a mating surface according to one embodiment of the present invention is characterized by comprising a first seal groove having a closed loop shape formed on at least one of the surfaces constituting the mating surface between a first member and a second member, a second seal groove having a closed loop shape formed outside the first seal groove on at least one of the surfaces, a first gasket having an endless shape fitted into the first seal groove, a second gasket having an endless shape fitted into the second seal groove, and a cleaning liquid storage section formed concavely between the first seal groove and the second seal groove on at least one of the surfaces and along the first seal groove and the second seal groove, for storing a cleaning liquid.

[0007] According to a sealing structure for mating surfaces according to one aspect of the present invention, when foreign matter enters and accumulates (crystal growth) on the mating surface (around the second seal groove) between the first and second components, creating a gap on the mating surface, cleaning liquid flows out from the cleaning liquid reservoir and dissolves and washes away the foreign matter accumulated on the mating surface (around the second seal groove). This allows the sealing performance of the second gasket to be restored. At the same time, the inside of the first seal groove remains liquid-tight. This allows the sealing performance of the mating surface to be maintained. [Effects of the Invention]

[0008] According to the present invention, even if foreign matter gets into and accumulates on the mating surfaces (seal grooves), it is possible to maintain the sealing properties of the mating surfaces. [Brief explanation of the drawings]

[0009] [Figure 1] 5A and 5B are diagrams showing a sealing structure of mating surfaces according to an embodiment; [Figure 2] 4A and 4B are cross-sectional views showing a first seal groove that constitutes the seal structure of the mating surfaces according to the embodiment, in which FIG. 4A is a cross-sectional view showing a state before fastening, and FIG. 4B is a cross-sectional view showing a state after fastening. [Figure 3] 5A and 5B are cross-sectional views showing a second seal groove that constitutes the seal structure of the mating surfaces according to the embodiment, in which FIG. 5A is a cross-sectional view showing a state before fastening, and FIG. 5B is a cross-sectional view showing a state after fastening. [Figure 4] 5A and 5B are views showing a second seal groove that constitutes the seal structure of the mating surfaces according to the embodiment. [Figure 5] 1 is a cross-sectional view showing a main part (in a normal state) of a sealing structure of mating surfaces according to an embodiment. [Figure 6] 1 is a cross-sectional view showing a main part of the sealing structure of the mating surfaces according to the embodiment (when foreign matter is deposited). [Figure 7] FIG. 2 is a diagram showing the mounting position of a water pump relative to an engine. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. In the drawings, the same elements are designated by the same reference numerals and redundant explanations will be omitted.

[0011] First, the configuration of the sealing structure of the mating surfaces according to the embodiment will be described with reference to FIGS. 1 to 7. FIG. 1 is a diagram showing the sealing structure of the mating surfaces. FIG. 2 is a cross-sectional view showing a first seal groove 31 constituting the sealing structure of the mating surfaces, with (a) showing the state before fastening and (b) showing the state after fastening. FIG. 3 is a cross-sectional view showing a second seal groove 32 constituting the sealing structure of the mating surfaces, with (a) showing the state before fastening and (b) showing the state after fastening. FIG. 4 is a diagram showing the second seal groove 32 constituting the sealing structure of the mating surfaces. FIG. 5 is a cross-sectional view showing a main part (normal state) of the sealing structure of the mating surfaces. FIG. 6 is a cross-sectional view showing a main part (when foreign matter has accumulated) of the sealing structure of the mating surfaces. FIG. 7 is a diagram showing the mounting position of the water pump 20 relative to the engine 10.

[0012] In this embodiment, a case will be described in which the mating surface seal structure according to the present invention is applied to a mating surface 30 between an oil pan upper 11 of an engine 10 and a water pump 20 (water pump cover).

[0013] Engine 10 may be of any type, but is, for example, a horizontally opposed four-cylinder gasoline engine. Engine 10 is, for example, a direct-injection engine that directly injects fuel into the cylinders. As shown in FIG. 7 , a water pump 20 that forcibly circulates engine coolant is attached to the side of an upper oil pan 11 of engine 10. Water pump 20 is driven, for example, by engine 10, and pressurizes and discharges the engine coolant. More specifically, for example, an accessory belt is wound around a drive pulley 12 attached to an end of a crankshaft of engine 10 and an accessory pulley (driven pulley) 13 attached to water pump 20. The driving force of engine 10 is transmitted to the accessory pulley, driving water pump 20.

[0014] The sealing structure of the mating surface between the water pump 20 (corresponding to the first member in the claims) and the oil pan upper 11 of the engine 10 (corresponding to the second member in the claims) is mainly composed of a first seal groove (inner groove) 31, a second seal groove (outer groove) 32, a first rubber gasket (O-ring) 33, a second rubber gasket (O-ring) 34, and a cleaning liquid storage section 35.

[0015] The first seal groove (inner groove) 31 is a groove in the shape of a closed loop formed on at least one surface side (the water pump 20 side).

[0016] The first rubber gasket (O-ring) 33 is formed endlessly and fitted into the first seal groove 31. The first rubber gasket (O-ring) 33 is, for example, an annular member with a circular cross section, and is preferably made of EPDM (ethylene propylene diene diene rubber) or the like, which has elasticity and excellent oil resistance, temperature resistance, etc. Furthermore, the first rubber gasket 33 is preferably resistant to cleaning fluids, which will be described later.

[0017] A pair of retaining portions (protrusions) 38 are formed at the open end of the first seal groove 31 so as to extend along the first seal groove 31 and protrude in a direction (approximately radial direction) perpendicular or substantially perpendicular to the extension direction of the first seal groove 31. In this embodiment, the retaining portions (protrusions) 38 have a two-stage configuration. The pair of retaining portions (protrusions) 38 restrict (restrain) the movement of the first rubber gasket (O-ring) 33 fitted in the first seal groove 31, and retain the first rubber gasket 33 in the first seal groove 31.

[0018] The second seal groove (outer groove) 32 is a closed loop groove formed on the outside of the first seal groove 31 on at least one surface side (the water pump 20 side).

[0019] The second rubber gasket (O-ring) 34 is formed endless and is fitted into the second seal groove 32. Like the above-described first rubber gasket 33, the second rubber gasket (O-ring) 34 is preferably made of, for example, EPDM. The first rubber gasket 33 and the second rubber gasket 34 form a liquid-tight seal to prevent leakage of cooling water (coolant) from the mating surface 30.

[0020] A plurality of release grooves (lateral grooves) 36 are formed on at least the bottom surface of the second seal groove 32, aligned in a direction (approximately a radial direction) perpendicular or substantially perpendicular to the extension direction of the second seal groove 32. When foreign matter enters and accumulates on the mating surface 30, causing a gap in the mating surface 30, the cleaning liquid flows out (is released) through the plurality of release grooves 36. Details will be described later.

[0021] Furthermore, on the other surface side (the oil pan upper 11 side of the engine 10) that forms the mating surface 30, a strip-shaped partition wall portion (side wall portion) 37 with a rectangular cross section is provided to protrude toward the second seal groove 32 side (one surface side) at a position facing (corresponding to) the inner side wall of the second seal groove 32. The partition wall portion (side wall portion) 37 becomes a partition wall (side wall) that separates the cleaning liquid storage portion 35 and the second seal groove 32 (i.e., forms a partition wall (side wall)) when the water pump 20 and the oil pan upper 11 of the engine 10 are fastened together (i.e., when the mating surface 30 is formed).

[0022] The partition wall (side wall) 37 can store the cleaning fluid when the water pump 20 and the oil pan upper 11 of the engine 10 are fastened together (i.e., when no gap is formed on the mating surface 30). On the other hand, when a gap is formed on the mating surface 30 (i.e., when a gap is formed between the partition wall (side wall) 37 and the bottom surface of the second seal groove), the cleaning fluid can be efficiently discharged.

[0023] A retaining portion (convex portion) 38 is formed at the opening end of the second seal groove 32 so as to protrude along the second seal groove 32 and in a direction (approximately radial direction) perpendicular or substantially perpendicular to the extension direction of the second seal groove 32. Furthermore, a retaining portion (convex portion) 38 is formed at the base end of the partition wall (side wall portion) 37 so as to protrude along the partition wall (side wall portion) 37 and in a direction (approximately radial direction) perpendicular or substantially perpendicular to the extension direction of the partition wall (side wall portion) 37. In this embodiment, the retaining portions (convex portions) 38 at the opening end of the second seal groove 32 and at the base end of the partition wall (side wall portion) 37 each have a two-stage configuration.

[0024] The retaining portions (convex portions) 38 at the opening end of the second seal groove 32 and at the base end of the partition portion (side wall portion) 37 regulate (suppress) the movement of the second rubber gasket (O-ring) 34 that is fitted into the second seal groove 32 as a pair, thereby retaining the second rubber gasket 34 within the second seal groove 32.

[0025] The cleaning liquid storage section (cleaning liquid pocket) 35 is formed in a concave shape between the first seal groove 31 and the second seal groove 32 (partition wall portion 37) on at least one surface side (the water pump 20 side) and along the first seal groove 31 and the second seal groove 32. The cleaning liquid storage section 35 stores (holds) a cleaning liquid (cleaner) that dissolves and washes away foreign matter accumulated on the mating surface 30. Here, the cleaning liquid is preferably one that has good detergency, is highly volatile, does not corrode rubber (EPDM), and is not prone to freezing, such as water or ethanol.

[0026] Here, the cleaning liquid can be filled by, for example, inserting a jig into the water pump 20 during temporary tightening so that a small gap is left above the mating surface 30, pouring an appropriate amount of cleaning liquid into the cleaning liquid reservoir 35, removing the jig, and then completely tightening the water pump 20 (closing the mating surface 30). Alternatively, a through-hole for pouring the cleaning liquid may be provided. In this case, the cleaning liquid can be filled by plugging the through-hole after pouring the cleaning liquid.

[0027] Here, the concentration (boiling point) of the cleaning liquid is adjusted (i.e., the volatility (vapor pressure) of the cleaning liquid is adjusted) so that the internal pressure of the cleaning liquid storage section 35 is higher than atmospheric pressure (external air pressure) when the engine 10 is running (operating). More specifically, it is preferable to adjust the volatility (vapor pressure) of the cleaning liquid by diluting ethanol with water, for example, so that the pressure inside the cleaning liquid storage section 35 is kept slightly higher than atmospheric pressure so that the cleaning liquid will spray out when foreign matter gets into and accumulates on the mating surface 30, creating a gap in the mating surface 30.

[0028] Ethylene glycol has a boiling point of 197.3°C and a viscosity of 16.1 mPas (16.1 mPas), which is higher than water. Therefore, it is less volatile than water. The more water evaporates, the higher the viscosity of the coolant becomes, resulting in reduced fluidity and cleaning power. In particular, salts do not dissolve in ethylene glycol, so cleaning by dissolving them is not possible. Meanwhile, ethanol has a viscosity of 1.2 and a boiling point of 78°C, while water has a viscosity of 1 and a boiling point of 100°C, providing the fluidity and volatility required for cleaning.

[0029] With the above-described configuration, first, under normal conditions (when no gaps are present on the mating surface 30), cleaning liquid is retained in the cleaning liquid reservoir 35 (between the first rubber gasket 33 and the second rubber gasket 34). That is, under normal conditions, both the first rubber gasket 33 and the second rubber gasket 34 are sealed, and both the coolant and cleaning liquid are retained without leaking or mixing. Furthermore, under normal conditions, the interior of the cleaning liquid reservoir 35, which retains the cleaning liquid, is approximately 80 to 90 percent filled with cleaning liquid, and the internal pressure is maintained at a slightly higher level (than atmospheric pressure) due to the volatilized cleaning liquid.

[0030] Thereafter, for example, a calcium chloride solution or the like containing foreign matter (corrosion products) enters the mating surface 30 (the periphery (outside) of the second rubber gasket 34), and as crystals of calcium chloride or the like grow on the foreign matter (and as the calcium chloride solution or the like flows into the gaps between the crystals and crystallization progresses), a negative pressure (push-back force) acts on the mating surface 30. As a result, gaps are formed in the mating surface 30.

[0031] When a gap occurs at the mating surface 30, a gap also occurs between the partition wall portion (side wall portion) 37 on the oil pan upper 11 side of the engine 10 and the second seal groove 32 on the water pump 20 side, and cleaning liquid flows out from that gap through the discharge groove 36.

[0032] The flowing cleaning liquid passes through the discharge groove 36 from the bottom of the second rubber gasket 34, reaches the accumulated foreign matter, and removes the foreign matter with the flow of the cleaning liquid. The cleaning liquid also dissolves the foreign matter, cleaning it. In this way, the foreign matter is removed (removed and cleaned) by the cleaning liquid, and the second rubber gasket 34 (mating surface 30) is restored to its normal state (sealing properties are restored). Therefore, after the removal and cleaning of the accumulated foreign matter is completed, normal function is restored except for the consumption of the minimum amount of cleaning liquid necessary.

[0033] More specifically, the temperature of the cooling water (coolant) when the engine is running (operating) reaches 70 to 80°C, which is the boiling point of ethanol, 78°C. (The boiling point of ethylene glycol, which is the coolant, is 197°C, so it hardly ever becomes a gas.) Therefore, the pressure inside the cleaning liquid reservoir 35 is maintained at a pressure equal to (or lower than) the mating surface pressure, and the pressure, gas, and liquid are in equilibrium.

[0034] Next, as calcium chloride or the like crystallizes on the mating surfaces 30, a negative pressure (push-back force) acts on the mating surfaces, creating a gap between the mating surfaces 30. This disrupts the pressure equilibrium, and vapor pressure equivalent to the mating surface pressure is released, causing the cleaning liquid (gas-liquid) to be sprayed in a spray. After the internal pressure drops due to the spray of the cleaning liquid, the cleaning liquid reservoir 35 is sealed by the second rubber gasket 34. Thereafter, the internal pressure returns to normal as the cleaning liquid evaporates, and the equilibrium state is restored.

[0035] On the other hand, the first rubber gasket 33 maintains sufficient sealing performance even when foreign matter accumulates, so that leakage of the cooling water (coolant) and deterioration of the cooling water (coolant) due to contamination with cleaning fluid do not occur.

[0036] As described above in detail, according to this embodiment, if foreign matter enters and accumulates (crystallizes) on the mating surface 30 (around the second seal groove 32) between the water pump 20 and the oil pan upper 11 of the engine 10, creating a gap in the mating surface 30, the cleaning liquid flows out from the cleaning liquid reservoir 35 and dissolves and washes away the foreign matter accumulated on the mating surface 30 (around the second seal groove 32). This allows the sealing performance of the second rubber gasket 34 to be restored. At the same time, the inside of the first seal groove 31 is kept (maintained) liquid-tight. As a result, even if foreign matter enters and accumulates on the mating surface 30 (second seal groove 32), the sealing performance of the mating surface 30 can be maintained. As secondary effects, resource savings and a reduction in replacement work hours can be expected due to improved durability of the water pump 20.

[0037] According to this embodiment, a plurality of release grooves 36 are formed on at least the bottom surface of the second seal groove 32 in a direction perpendicular or substantially perpendicular to the extension direction of the second seal groove 32. Therefore, when foreign matter enters and accumulates on the mating surface 30, causing a gap in the mating surface 30, the cleaning liquid can be made to flow out (released) through the plurality of release grooves 36.

[0038] According to the present embodiment, a partition wall portion (side wall portion) 37 that serves as a partition wall (side wall) separating the cleaning fluid reservoir 35 from the second seal groove 32 when the water pump 20 and the oil pan upper 11 of the engine 10 are fastened together is provided on the other surface side (the oil pan upper 11 side of the engine 10) that forms the mating surface 30 and at a position facing (corresponding to) the inner side wall of the second seal groove 32, and protrudes toward the second seal groove 32. Therefore, cleaning fluid can be stored when the water pump 20 and the oil pan upper 11 of the engine 10 are fastened together (when no gap is formed in the mating surface 30), and cleaning fluid can be efficiently discharged when a gap is formed in the mating surface 30.

[0039] According to this embodiment, holding portions (protrusions) 38 that restrict (restrain) the movement of the first rubber gasket 33 and the second rubber gasket 34 are formed at the opening ends of the first seal groove 31 and the second seal groove 32, respectively, and along the first seal groove 31 and the second seal groove 32. Therefore, the first rubber gasket 33 and the second rubber gasket 34 can be held in place appropriately.

[0040] According to this embodiment, the concentration (boiling point) of the cleaning liquid is adjusted (i.e., the volatility (vapor pressure) of the cleaning liquid is adjusted) so that the internal pressure of the cleaning liquid storage section 35 is higher than atmospheric pressure (external pressure) when the engine is running (operating). Therefore, when foreign matter enters and accumulates on the mating surface 30, causing a gap in the mating surface 30, the cleaning liquid can be sprayed out. This makes it possible to more effectively remove the foreign matter.

[0041] Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and various modifications are possible. For example, in the above embodiments, the mating surface seal structure of the present invention is applied to the mating surface 30 between the engine 10 (oil pan upper 11) and the water pump 20, but it can also be applied to mating surfaces of other members.

[0042] Furthermore, the shapes and sizes of the first seal groove 31, second seal groove 32, release groove 36, partition wall portion 37, and retaining portion 38, as well as the materials, shapes, and sizes of the first rubber gasket 33 and second rubber gasket 34, are merely examples and may be changed (set) as desired depending on requirements, etc. For example, the first seal groove 31, second seal groove 32, and cleaning liquid reservoir 35 may also be formed on the engine 10 (oil pan upper 11) side. A release groove 36 may also be formed on the inner surface of the second seal groove 32. [Explanation of symbols]

[0043] 10 Engine 11 Oil pan upper (second component) 20 Water pump (first component) 30 Mating surface 31 First seal groove 32 Second seal groove 33 First rubber gasket (O-ring) 34 Second rubber gasket (O-ring) 35 Cleaning fluid reservoir 36 Release groove 37 Partition wall (side wall) 38 Retaining part (convex part)

Claims

1. a first seal groove having a closed loop shape formed on at least one of the mating surfaces of the first member and the second member; a second seal groove having a closed loop shape formed outside the first seal groove on at least the one surface side; an endless first gasket fitted into the first seal groove; an endless second gasket fitted into the second seal groove; a cleaning liquid storage portion that is formed concavely between the first seal groove and the second seal groove on at least one of the surfaces and along the first seal groove and the second seal groove, and that stores a cleaning liquid.

2. The sealing structure of the mating surfaces according to claim 1, characterized in that at least the bottom surface of the second seal groove is provided with a plurality of release grooves formed in a direction perpendicular or substantially perpendicular to the extension direction of the second seal groove.

3. The sealing structure of the mating surface described in claim 2, characterized in that it is provided with a band-shaped partition portion that protrudes toward the second seal groove on the other surface side that constitutes the mating surface and at a position opposite the inner side wall of the second seal groove, and that serves as a partition that separates the cleaning liquid storage portion and the second seal groove when the first member and the second member are fastened together.

4. The sealing structure of the mating surfaces described in claim 3, characterized in that it is provided with a retaining portion formed at the opening end of each of the first seal groove and the second seal groove, and along each of the first seal groove and the second seal groove, so as to protrude in a direction perpendicular or approximately perpendicular to the extension direction of each of the first seal groove and the second seal groove, and which restricts and suppresses the movement of each of the first gasket fitted in the first seal groove and the second gasket fitted in the second seal groove.

5. 5. The sealing structure for mating surfaces according to claim 4, wherein the concentration of the cleaning liquid is adjusted so that the internal pressure of the cleaning liquid reservoir is higher than atmospheric pressure.

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