Seal structure and electric pump

Abstract

To provide a seal structure formed by a liquid gasket with improved sealing reliability, and to provide an electric pump.SOLUTION: A seal structure has: a first member 5 formed with an opening; a second member 7 which closes the opening of the first member 5; and a liquid gasket 9 provided in a seal groove 10 formed at a mating part between the first member 5 and the second member 7 and having a labyrinth structure which is formed by curing a curable liquid 9.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a seal structure and an electric pump provided with the seal structure.

Background Art

[0002] For example, in order to prevent water from entering the inside of an electric pump or oil inside from leaking, a gasket for sealing the gap between parts is generally used. As this gasket, a liquid gasket obtained by applying a curable liquid between parts and then curing it may be used. For example, in Patent Document 1 below, a curable liquid (liquid gasket) is applied between the mating surfaces of a cylinder block and an upper oil pan, and a seal structure is constituted by the liquid gasket obtained by curing this curable liquid (see particularly paragraphs 0011 to 0015 and FIG. 2 of Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As described in Patent Document 1, when a liquid gasket is formed by a curable liquid at the contact portion between mating surfaces (flat surfaces), since the seal surface is only in one direction, the seal reliability is low depending on the posture of the pump against water intrusion from the outside, and it may not be possible to secure a sufficient seal surface length. Further, due to the imperfection of the surface flatness of the members to be sealed (in this document, the cylinder block and the upper oil pan), and the shape change of the parts due to the tightening of the bolts, a portion where the members to be sealed are in direct contact with each other (a portion without a liquid gasket) may occur, and the sealing performance may be reduced. Further, when the members to be sealed are made of different materials, the relative displacement amount between the members to be sealed increases due to the difference in the linear expansion coefficient, and the liquid gasket may be damaged.

[0005] Therefore, an object of the present invention is to improve the sealing reliability of a liquid gasket obtained by curing a curable liquid.

Means for Solving the Problem

[0006] To solve this problem, in the present invention, a first member having an opening formed therein, a second member closing the opening of the first member, and a liquid gasket provided in a seal groove formed in a mating portion between the first member and the second member, the liquid gasket having a labyrinth structure formed by curing a curable liquid are provided to form a seal structure.

[0007] In this way, high sealing reliability due to the labyrinth structure can be ensured. Moreover, even if the machining accuracy of the first member and the second member is at the die molding level, as long as relative displacement due to an error in the machining accuracy of both members or a difference in the linear expansion coefficient occurs in the seal groove of the mating portion, the followability of the liquid gasket can be ensured, and a desired labyrinth structure is maintained without the liquid gasket being partially interrupted. For this reason, additional machining for obtaining high surface accuracy of the mating surface is not required, and the machining cost can be suppressed.

[0008] In the above configuration, it is preferable that the labyrinth structure has different extending direction components in two or more directions in a cross section along the mounting direction of the second member to the first member.

[0009] In this way, the labyrinth structure becomes more complicated, and it is possible to more effectively prevent water from entering from the outside and oil from leaking from the inside.

[0010] In the above configuration, it is preferable that at least one of the different extending direction components in two or more directions extends in a direction different from the gravitational direction.

[0011] In this way, when water is splashed from the outside, it is difficult for the water to penetrate into the labyrinth structure extending in a direction different from the gravitational direction, and it is difficult to accumulate in the vicinity thereof, so that a higher waterproof effect is exhibited.

[0012] In each of the above configurations, It is preferable that the labyrinth structure is formed by uneven portions formed on at least one of the first member and the second member.

[0013] In this way, a labyrinth structure having a desired shape can be easily formed by processing uneven portions on at least one of the first member and the second member.

[0014] In each of the above configurations, It is preferable that the structure has a relief groove that communicates with the seal groove and allows a part of the curable liquid filled in the seal groove to escape to the inside of the opening.

[0015] In this way, the amount of the curable liquid leaking to the outside of the opening can be relatively reduced, so that the work of wiping off the curable liquid leaking to the outside can be omitted or simplified.

[0016] In each of the above configurations, It is preferable that a contact portion where the first member and the second member are in direct contact without passing through the liquid gasket is formed over the entire circumference of the opening.

[0017] By doing so, the rigidity can be enhanced by the contact between the first member and the second member at the abutting portion, and the sealing performance can be further improved. Also, since a predetermined sealing property is ensured by the abutting portion, for example, in the manufacturing process of an electric oil pump, a sealing performance inspection such as an air leak test can be performed before the hardening of the liquid gasket. This abutting portion may be formed either inside or outside the liquid gasket. However, if it is on the outside, it can actively prevent water from entering from the outside and reaching the sealing portion, so that the sealing performance can be further improved.

[0018] In each of the above configurations, It is preferable to have a configuration having a notch portion that communicates with the seal groove and allows a part of the curable liquid filled in the seal groove to escape to the outside of the opening.

[0019] By doing so, when the second member is attached to the first member, the location and amount where the curable liquid leaks can be managed, and the filling state of the curable liquid can be visually confirmed. Also, by allowing the curable liquid to leak only from the position of the notch portion, the wiping operation of the leaked curable liquid can be omitted or simplified.

[0020] The seal structure according to each of the above configurations is suitable for an electric pump in which preventing water from entering from the outside and preventing oil from leaking to the outside are important.

Effects of the Invention

[0021] According to the seal structure of this invention, the sealing reliability of the liquid gasket using the curable liquid can be easily enhanced by the labyrinth structure. Also, the reliability of the electric pump adopting this seal structure can be enhanced.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Mode for Carrying Out the Invention

[0023] The electric pump 2 provided with the seal structure 1 (first embodiment) according to the present invention will be described with reference to FIGS. 1 to 6. This electric pump 2 is an electric oil pump such as a trochoid pump used for various applications such as vehicle transmissions, brakes, and steering operations. This electric pump 2 is mounted on a vehicle or the like in the vertical position direction shown in FIG. 1

[0024] Inside the housing 3 of this electric pump 2, a motor main body and a pump section (both not shown) are provided. The drive shaft 4 of this motor main body is rotatably held by a bearing 6 attached to a bearing holding member 5 (first member). The bearing holding member 5 is fixed to the end of the housing 3 by bolts (not shown). An opening is formed in the bearing holding member 5. A cover member 7 (second member) that closes this opening is fixed to the bearing holding member 5 by bolts 8 (see FIG. 2). A liquid gasket 9 is provided at the mating portion between the bearing holding member 5 and the cover member 7, preventing the intrusion of water or the like from the outside to the inside of the electric pump 2 and the leakage of the internal oil.

[0025] The liquid gasket 9 is formed by curing a curable liquid such as a silicon-based liquid (hereinafter, the same reference numeral as the liquid gasket 9 is used), and the shape after curing has a labyrinth structure. This labyrinth structure is formed in a seal groove 10 formed so as to surround the opening of the bearing holding member 5, and has different extending direction components in two or more directions in a cross section along the mounting direction of the cover member 7 to the bearing holding member 5.

[0026] In the present embodiment, a labyrinth structure in the shape of a U-shaped cross section, that is, composed of two horizontal extending components and one vertical extending component, is formed. This U-shaped cross-section labyrinth structure makes the bearing holding member 5 and the cover member 7 in surface contact at the attachment portion of the bolt 8, and is formed by inserting the protrusion 11 (concavo-convex portion) formed on the peripheral edge of the cover member 7 so that it does not contact both side surfaces and the bottom surface of the seal groove 10 formed in the bearing holding member 5 (see FIGS. 4 and 5).

[0027] Since this electric pump 2 (seal structure 1) is mounted on a vehicle or the like in the vertical position direction shown in FIG. 1 as described above, as shown in FIG. 6, liquid droplets such as water droplets drip along the direction of gravity shown in this figure (see arrow d in FIG. 6). At this time, since the horizontal extension component of the liquid gasket 9 having a U-shaped cross section is perpendicular to the direction of gravity (the dripping direction of the liquid droplets), it is difficult for the liquid droplets to stay near the end of the liquid gasket 9 (see the × mark in FIG. 6), and the liquid droplets can be smoothly flowed in a direction away from the liquid gasket 9 (see the ○ mark in FIG. 6). Thereby, it is possible to prevent water from entering the inside of the electric pump 2 from the seal groove 10 of the liquid gasket 9.

[0028] In this way, by adopting the labyrinth structure for the liquid gasket 9, high sealing reliability can be ensured. Moreover, even if the machining accuracy of the bearing holding member 5 and the cover member 7 is at the die forming level, as long as relative displacement due to errors in the machining accuracy of the two members 5 and 7 and differences in the linear expansion coefficients occurs within the seal groove 10 of the mating portion, the followability of the liquid gasket 9 can be ensured, and the desired labyrinth structure is maintained without the liquid gasket 9 being partially interrupted. For this reason, additional machining for obtaining high surface accuracy of the mating surface is not required, and the machining cost can be suppressed.

[0029] In this embodiment, the labyrinth structure has a U-shaped cross section and a horizontal extension component perpendicular to the direction of gravity, but the labyrinth structure can also have an L-shaped cross section and an extension component in a direction different from (not perpendicular to) the direction of gravity. Even in this configuration, the effect of preventing water intrusion from the liquid gasket 9 can be sufficiently exhibited.

[0030] The second embodiment of the seal structure 1 according to the present invention is shown in FIGS. 7 and 8. The seal structure 1 according to this embodiment has the same basic configuration as the seal structure 1 according to the first embodiment, but is different in that a notch 12 communicating with a seal groove 10 formed in the mating portion between the bearing holding member 5 and the cover member 7 is formed. The notch 12 is formed at two locations, above and below, of the seal groove 10, and has a function of allowing a part of the curable liquid 9 filled in the seal groove 10 to escape to the outside of the opening of the bearing holding member 5.

[0031] The construction procedure of this seal structure 1 is shown in FIG. 9. First, the seal groove 10 formed at the periphery of the opening of the bearing holding member 5 is filled with the curable liquid 9. Next, before the curable liquid 9 hardens, the cover member 7 is attached so as to close the opening of the bearing holding member 5. At this time, the ridge 11 formed at the peripheral edge of the cover member 7 is inserted into the seal groove 10, and the curable liquid 9 in the seal groove 10 flows to the outside of the opening (see arrow f1 in FIG. 9(c)) and the inside of the opening (see arrow f2 in FIG. 9(c)), respectively. A part of the curable liquid 9 that has flowed to the outside of the opening is allowed to escape through the notch 12 (see arrow f' in FIG. 9(c)). When the curable liquid 9 is hardened, the construction of the seal structure 1 is completed.

[0032] In this way, by allowing the curable liquid 9 to escape through the notch 12, it is possible to manage the location and amount where the curable liquid 9 leaks when the cover member 7 is attached to the bearing holding member 5, and the filling state of the curable liquid 9 can be visually confirmed. Further, by allowing the curable liquid 9 to leak only from the position of the notch 12, the wiping operation of the leaked curable liquid 9 can be omitted or simplified.

[0033] Also, by forming the notch 12, droplets such as water droplets in the vicinity of the liquid gasket 9 can be quickly discharged, so that it is possible to further prevent water from entering the inside of the electric pump 2 from the seal portion of the liquid gasket 9. In this embodiment, the notches 12 are formed at two locations, above and below, of the seal groove 10, but the number and formation position thereof can be appropriately changed.

[0034] A third embodiment of the seal structure 1 according to the present invention is shown in FIG. 10. The seal structure 1 according to this embodiment also has the same basic configuration as the seal structure 1 according to the first embodiment, but is different in that a relief groove 13 communicating with a seal groove 10 formed in a mating portion between the bearing holding member 5 and the cover member 7 is formed. This relief groove 13 is formed on the entire inner circumference of the seal groove 10 and has a function of allowing a part of the curable liquid 9 filled in the seal groove 10 to escape to the inside of the opening of the bearing holding member 5 when the cover member 7 is attached to the opening of the bearing holding member 5.

[0035] The seal groove 10 is preset so that a predetermined amount of the curable liquid 9 is automatically filled by a filling device. However, due to an operation error of the filling device, a slightly larger amount of the curable liquid 9 than the predetermined amount is filled, and when the cover member 7 is attached, more curable liquid 9 may overflow from the seal groove 10 than expected. Further, even if a predetermined amount of the curable liquid 9 is filled in the seal groove 10, the curable liquid 9 may similarly overflow from the seal groove 10 due to the machining accuracy of the seal groove 10 and the protrusion 11. As described above, by allowing the curable liquid 9 to escape to the relief groove 13, the amount of the curable liquid 9 leaking to the outside of the opening can be relatively reduced, so that the wiping operation of the curable liquid 9 leaking to the outside can be omitted or simplified. In this embodiment, the relief groove 13 is formed on the entire inner circumference of the seal groove 10, but the formation position can be appropriately changed.

[0036] A fourth embodiment of the seal structure 1 according to the present invention is shown in FIG. 11. The seal structure 1 according to this embodiment also has the same basic configuration as the seal structure 1 according to the first embodiment, but is different in that a contact portion 14 where the bearing holding member 5 and the cover member 7 are in direct contact without intervening a liquid gasket 9 is formed over the entire outer circumference of the opening of the bearing holding member 5. In this contact portion 14, the bearing holding member 5 and the cover member 7 are in strong surface contact by the tightening force of the bolt 8 (see FIG. 2). Therefore, the rigidity of the entire seal structure 1 is increased, and the sealing performance can be improved.

[0037] A fifth embodiment of the seal structure 1 according to the present invention is shown in FIG. 12. The seal structure 1 according to this embodiment is common to the seal structure 1 according to the fourth embodiment in that the contact portion 14 is formed, but is different in that the contact portion 14 is formed over the entire inner circumference of the opening of the bearing holding member 5. In this embodiment, the inner wall of the opening side of the seal groove 10 is press-fitted inside the ridge 11, and by this press-fitting, the bearing holding member 5 and the cover member 7 are in strong surface contact. Thereby, the rigidity of the entire seal structure 1 is increased as in the fourth embodiment, and the sealing performance can be improved.

[0038] Further, in the seal structure 1 according to the fourth and fifth embodiments, since the sealing effect by the contact portion 14 is exhibited, a leak test for inspecting the airtightness of the seal structure 1 can be performed before the hardening of the liquid gasket 9 (curable liquid 9). For this reason, the total time required until the shipment of the product can be shortened.

[0039] In each of the above embodiments, the labyrinth structure is formed by inserting the ridge 11 as the concavo-convex portion 11 formed on the peripheral edge portion of the cover member 7 into the seal groove 10 formed in the bearing holding member 5. However, a seal groove 10 may be formed in the cover member 7, and various configurations such as a configuration in which the concavo-convex portion 11 is formed in the bearing holding member 5, or a configuration in which the concavo-convex portions 11, 11 are formed in both the bearing holding member 5 and the cover member 7 may be adopted.

[0040] It should be considered that all the embodiments disclosed this time are illustrative in all respects and not restrictive. Therefore, the scope of the present invention is shown not by the above description but by the claims, and it is intended that all meanings equivalent to the claims and all modifications are included.

Description of reference numerals

[0041] 1 Seal structure 2 Electric pump 3 Housing 4 Drive shaft 5 Bearing holding member (first member) 6 Bearing 7 Cover member (second member) 8 Bolt 9 Liquid gasket (curable liquid) 10 Seal groove 11 Ridge (concave-convex part) 12 Notch 13 Relief groove 14 Contact part

Claims

1. A first member (5) having an opening formed therein, A second member (7) closing the opening of the first member (5), A liquid gasket (9) provided in a seal groove (10) formed at a mating portion between the first member (5) and the second member (7), formed by curing a curable liquid (9), and having a labyrinth structure after curing, having, configured by attaching the second member (7) to the first member (5) before the curable liquid (9) cures, The labyrinth structure is formed by the seal groove (10) formed in one of the first member (5) or the second member (7) and a ridge (11) formed in the other of the first member (5) or the second member (7), A seal structure provided between an outer surface of the ridge (11) and an inner surface of the seal groove (10) such that a horizontal extension component of the liquid gasket (9) faces the liquid droplet dripping along the gravitational direction from a direction perpendicular to the gravitational direction.

2. The seal structure according to claim 1, wherein the labyrinth structure has extension direction components in two or more different directions in a cross-section along the mounting direction of the second member (7) to the first member (5).

3. The seal structure according to claim 2, wherein at least one extension direction component of the two or more different extension direction components extends in a direction different from the gravitational direction.

4. The seal structure according to any one of claims 1 to 3, further comprising a relief groove (13) communicating with the seal groove (10) and allowing a part of the curable liquid (9) filled in the seal groove (10) to escape to the inside of the opening.

5. The seal structure according to any one of claims 1 to 4, wherein a contact portion (14) where the first member (5) and the second member (7) are in direct contact without passing through the liquid gasket (9) is formed over the entire circumference of the opening.

6. The sealing structure according to any one of claims 1 to 5, further comprising a notch portion (12) that communicates with the seal groove (10) and allows a part of the curable liquid (9) filled in the seal groove (10) to escape to the outside of the opening.

7. An electric pump provided with the sealing structure (1) according to any one of claims 1 to 6.

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