Sealing structure and motor with reduction gear

Abstract

A sealing structure for sealing between a cover (2) for closing an opening portion of a housing (4) in which components are accommodated and the housing (4) by means of a sealing element (3), wherein the cover (2) has an annular recessed portion (20) attached to an end portion of a peripheral wall (43) forming the opening portion of the housing (4), wherein the sealing element (3) is formed integrally with the cover (2) and integrally comprises a projection portion (30) formed in the recessed portion (20) around the entire circumference from a bottom portion (20a) of the recessed portion (20), characterized in that the cover (2) has a plurality of through holes (21) extending through the bottom portion (20a) of the recessed portion (20) and spaced from each other in the circumferential direction, the sealing element (3) integrally comprises a plurality of anchor portions (31),which engage in the through-holes (21) and fix the sealing element (3) to the cover (2), a projecting portion (32) is provided between at least several anchor portions (31) in the recessed portion (20), which projecting portion closes a gap between the projecting portion (30) and an inner wall (20c) of the recessed portion (20), and in the recessed portion (20), on the side opposite the projecting portion (32) with respect to the projecting portion (30), a contact surface (20d) is provided, against which an end surface of the peripheral wall (43) of the housing (4) rests.

Description

Technical area

[0001] The present invention relates to a structure for sealing between a cover closing an opening portion of a case in which components are accommodated and the case, and a motor with a reduction gear to which this sealing structure is applied. General state of the art

[0002] A device is known from the prior art in which a housing in which components are housed is tightly closed by attaching a cover. In this device, a sealing element such as a packing or an O-ring is inserted between the cover and the housing, thereby preventing foreign matter or moisture from entering from the outside. For example, JP 2012 229 724 A discloses a motor with a reduction gear, in which a packing is inserted between a gear housing portion (housing) in which a reduction gear for reducing the rotation of a motor portion is housed, and a cover covering an opening portion side of the gear housing portion. In this motor, a packing (sealing element) is first attached to the outer peripheral portion on the opening portion side of the gear housing portion, after which the cover is attached.

[0003] DE 196 06 532 A1 discloses a sealing structure according to the preamble of claim 1. Summary of the inventionObject of the present invention

[0004] However, if the sealing assembly step of the housing and the cover is performed automatically by an automatic machine, it is desirable to reduce the number of components for the purpose of improving assembly efficiency by integrally forming the cover and the sealing element, thus allowing them to be handled as a single element rather than as separate elements. As a method for integrally forming these elements, for example, an outsert molding method is conceivable for molding the sealing element onto the cover. An example of this method is described with reference to Fig. 6A-6C. Fig. 6A is a plan view of the back of the cover after outsert forming, and Fig. 6B and Fig. 6C are sectional views in the direction of arrow BB and CC respectively from Fig. 6A during outsert formation.

[0005] As in Fig. As shown in Figures 6A-6C, a recessed portion 20 is provided on the outer peripheral portion of the cover 2, which recessed portion is mounted on a peripheral wall forming the opening portion of the housing. A plurality of through holes 21 (six in the figure) are provided circumferentially on the recessed portion 20. Some of these through holes 21 (for example, every second one, i.e., three) serve as gates 7 for pouring resin. As shown in Fig. 6B and Fig. 6C, an upper tool 5 and a lower tool 6 for forming a sealing element 9 are arranged on an outer surface 20f and an inner surface 20g of the recessed portion 20 of the cover 2, respectively.

[0006] In the upper tool 5, a round, disc-shaped cavity 5a (hereinafter referred to as "first cavity 5a") is provided coaxially with the through holes 21, the diameter of which is larger than the diameter of the through holes 21. In the lower tool 6, at the center point in the radial direction of the recessed section 20 (in Fig. 6A on the dashed two-dot line) extending, annular cavity 6a (hereinafter "second cavity 6a") is provided, which is deeper than the first cavity 5a.

[0007] When resin is supplied through the multiple gates 7, as shown in Fig. 6B, the first cavity 5a connected to the gates 7 is filled with synthetic resin, and the second cavity 6a is also filled with synthetic resin via the through holes 21. In addition, as shown in Fig. 6C, the first cavity 5a is also molded by supplying resin from the second cavity 6a through the through-holes 21 adjacent to the gates 7. The resin cured in the first cavity 5a and the through-holes 21 serves as an anchor portion 91 for fixing the sealing element 9 to the cover 2. The resin cured in the second cavity 6a, in turn, forms a protruding part (protruding portion 90) that is compressed relative to the housing.

[0008] However, in outsert molding, the upper mold 5 and the lower mold 6 are separated from each other after the resin has been filled in, even before it has completely cured. Therefore, the resin filled into the second cavity 6a (i.e., the projection portion 90) is Fig. 6A, the sealing member 90 is unstable at a radial position between it and the armature portion 91, resulting in a problem of circumferential deflection. This is because the radial position of the protrusion portion 90 is secured only at the position of the armature portion 91 against radially inward contraction of the protrusion portion 90 during resin curing. If the sealing member 90 deflects in the circumferential direction, sufficient tight adhesion to the pressing surface on the housing side is not possible, so there is a risk of insufficient sealing performance. This problem also arises when a sealing member is integrally formed for a cover for closing a housing that houses components other than a motor (for example, the reduction gear of Japanese Patent Laid-Open No. 2012-229724).

[0009] The present invention, made in view of these problems, relates to a structure for sealing between a housing and a cover using a sealing element. It is an object of the invention to improve sealing performance while enabling axial and radial positioning between the cover and the housing. It is also an object of the invention to provide a motor with a reduction gear, in which the assembly process of the housing and cover can be performed automatically, while improving sealing performance. Means of solving the task

[0010] A sealing structure disclosed here is a structure for sealing between a cover for closing an opening portion of a housing in which components are accommodated and the housing according to claim 1. Furthermore, a motor according to the invention with a sealing structure according to claim 7 is disclosed. Advantageous further developments are the subject of the dependent claims. Effect of the invention

[0011] According to the disclosed sealing structure, the protruding portion, which closes the gap between the protrusion portion and the inner wall of the recessed portion, can stabilize the position of the protrusion portion between adjacent anchor portions in the radial direction because it is provided at least between the anchor portions. Since bending of the protrusion portion in the circumferential direction can be prevented in this way, the sealing performance can be enhanced.

[0012] Furthermore, according to the disclosed motor with a reduction gear, sealing performance can be improved. Furthermore, by integrally forming the cover and the sealing element, the number of components can be reduced, thereby increasing assembly efficiency using an automated machine. Short description of the characters

[0013] They show: Fig. 1 is a plan view of a motor with a reduction gear according to an embodiment; Fig. 2 a sectional view in the direction of arrow AA Fig. 1; Fig. 3 a perspective view of a gearbox housing of the engine of Fig. 1, viewed from the side of an opening section; Fig. 4 is a perspective view of a transmission cover mounted on the transmission housing of Fig. 3 is attached; Fig. 5 is a perspective sectional view under magnification of a part on the back of the gear cover of Fig. 4; and Fig. 6A-6C are views for explaining the task, wherein 6A is a plan view of the back of the gear cover after forming a sealing element, 6B is a sectional view in the direction of arrow BB of Fig. 6A during the formation of the sealing element and 6C a sectional view in the direction of arrow CC from Fig. 6A when forming the sealing element. Embodiment of the invention

[0014] With reference to the figures, a sealing structure will be described as an exemplary application to a motor with a reduction gear. The following embodiment is merely exemplary and is not intended to preclude the application of various modifications or techniques not set forth in the embodiment. The individual configurations of the present embodiment allow for various modifications without departing from the scope thereof. Substitutions and omissions are also possible as needed, as are suitable combinations. 1. Structure1-1. Motor with reduction gear

[0015] Fig. 1 is a plan view of a motor 1 with a reduction gear (hereinafter referred to as “motor 1”) according to the present embodiment, and Fig. 2 is a sectional view in the direction of arrow AA of Fig. 1. In the present embodiment, the description will be made using the example of the application of the motor 1 to a vehicle power window system. As shown in Fig. 1 and Fig. 2, the engine 1 includes a motor section 10 that generates output power and a reduction mechanism 13 that reduces the rotation of the motor section 10.

[0016] The motor section 10 is, for example, a brushed DC motor comprising a rotor and a stator (both not shown) housed in a housing 11. A shaft 12 of the motor section 10 is supported at one end on the housing 11, while the other end extends into the interior of a gear case 4 coupled to the housing 11. The housing 11 has the shape of a cylinder with a bottom and is coupled to the gear case 4 by connecting a flange portion 11a, which is provided in the vicinity of an opening portion (not shown), to a connecting portion 47 (see Fig. 3) of the gearbox housing 4.

[0017] The gear housing 4 (casing) is a housing for accommodating the reduction mechanism 13 (component), which has two receiving portions 41, 42. The reduction mechanism 13 includes a worm 13A to which the rotation of the motor portion 10 is transmitted, and a worm wheel 13B having a tooth portion meshing with the worm 13A. The worm 13A is a gear fixed to the other end of the shaft 12 and rotates integrally with the shaft 12. The worm wheel 13B is a gear meshing with the worm 13A.

[0018] In the present embodiment, a driven gear 14 is provided integrally with the worm gear 13B. The driven gear 14 meshes with a gear provided on a driven member (not shown) and drives the driven member, and is arranged coaxially with the worm gear 13B. As the driven member, for example, a window regulator can be cited. The motor 1 amplifies the output of the motor portion 10 by reducing the rotation of the shaft 12 through the reduction gear 13, and the amplified rotational driving force is output from the driven gear 14. In the motor 1 of the present embodiment, a step portion 15 is provided between the worm gear 13B and the driven gear 14, integrally therewith. An O-ring 16 is attached to the step portion 15.The structure of the motor 1 is only an example, and the worm gear 13B and the output gear 14 may also be provided separately.

[0019] The worm 13A is accommodated in one receiving section 41 of the gear housing 4, and the worm wheel 13B is accommodated in the other receiving section 42. Hereinafter, the former is referred to as the first receiving section 41 and the latter as the second receiving section 42. As shown in Fig. As shown in Figures 1-3, the second receiving portion 42 has the shape of a cylinder with a bottom, and a circular opening portion 40 is formed by a peripheral wall 43. The first receiving portion 41 is arranged adjacent to the outer side of a peripheral wall 43 of the second receiving portion 42.

[0020] The first receiving portion 41 and the second receiving portion 42 communicate via a communication hole 44 provided through a part of the peripheral wall 43 of the second receiving portion 42. The communication hole 44 is a hole through which a portion of the worm 13A projects into the interior of the second receiving portion 42, and through the communication hole 44, the worm 13A and the tooth portion of the worm wheel 13B engage in the second receiving portion 42. A support shaft 46 is provided upright on a bottom portion 45 of the second receiving portion 42, the height of which is greater than the peripheral wall 43. The worm wheel 13B and the driven gear 14 are rotatably supported by the support shaft 46.

[0021] A gear cover 2 (cover) is attached to the opening portion 40 of the gear housing 4, to which a sealing packing 3 (sealing element) is integrally formed. As shown in Fig. 4, the outer shape of the gear cover 2 is round and curved such that its center portion and outer peripheral portion are slightly higher than its radially central portion. A round output hole 22 extends through the center portion of the gear cover 2, and a cylindrical vertical wall 23 is provided upright thereon, the inner diameter of which is larger than the diameter of the output hole 22. The output hole 22 is an opening from which the support shaft 46 and the output gear 14 protrude outward. The vertical wall 23, in turn, is a part between which the O-ring 16 is inserted and the stepped portion 15, and which serves to seal the center portion side of the gear cover 2.

[0022] A recessed portion 20 is provided on the outer peripheral portion of the transmission cover 2, which is attached to the peripheral wall 43. The recessed portion 20 is an annular location where the packing 3 is provided to seal the outer peripheral side of the transmission cover 2. The sealing structure of the second receiving portion 42 of the transmission case 4 and the outer peripheral portion of the transmission cover 2 will be described in detail below. In the following description, the front end side of the support shaft 46 is referred to as the upper side, and the opposite side (the side of the lower side portion 45) is referred to as the lower side. 1-2. Sealing structure

[0023] Fig. 5 is a perspective sectional view under magnification of a part on the back of the gear cover 2 of Fig. 4. As in Fig. 2 and Fig. As shown in Figure 5, the recessed portion 20 of the transmission cover 2 is formed such that its radial sectional shape resembles a downwardly open square bracket. The recessed portion 20 is formed by an annular bottom portion 20a and an outer wall 20b and an inner wall 20c, both of which are cylindrical.

[0024] As in Fig. As shown in Figure 2, in a state where the transmission cover 2 is attached to the transmission case 4 (hereinafter, the "attached state"), the bottom portion 20a is disposed above the outer wall 20b and the inner wall 20c. An axially short part and a long part are provided on the outer wall 20b. The transmission cover 2 is fixed to the transmission case 4 by caulking a lower end portion 20e of the axially long part of the outer wall 20b.

[0025] As in Fig. 2 and Fig. 3, the end portion of the peripheral wall 43 is formed thickly, with only its outer diameter being slightly larger. Provided at the end portion are an upwardly facing flat pressing surface 43a and an end wall 43b projecting upwardly from a radially outer end portion of the pressing surface 43a. The pressing surface 43a is a surface against which the packing 3 is pressed, and the end wall 43b is a part that abuts the recessed portion 20 of the transmission cover 2 and determines the axial position of the transmission cover 2 and the transmission housing 4.

[0026] The packing 3 of the present embodiment is formed by outsert molding at the recess portion 20. As shown in Fig. As shown in Figure 5, the gear cover 2 has a plurality of through holes 21 extending through the bottom portion 20a, at least one of which serves as a gate for pouring resin. The plurality of through holes 21 are spaced apart from each other in the circumferential direction. The gear cover 2 of the present embodiment has six through holes 21 equally spaced in the circumferential direction of the recessed portion 20, with every other through hole 21, i.e., three through holes 21, serving as a gate.

[0027] The seal pack 3 of the present embodiment integrally comprises a protrusion portion 30 for sealing between it and the transmission case 4, anchor portions 31 that fix the seal pack 3 to the transmission cover 2, and a protruding portion 32 that determines the position of the protrusion portion 30 in the radial direction. The protrusion portion 30 is a part that protrudes from the bottom portion 20a in the recessed portion 20 around the entire circumference, and the sectional shape of its front end portion in the radial direction is approximately semicircular. A protrusion amount P from the bottom portion 20a is set such that the protrusion portion 30 is press-deformed by the end portion of the peripheral wall 43 in the attached state. That is, the protrusion amount P is set such that the front end portion of the protrusion portion 30 and the end portion of the peripheral wall 43 overlap in the attached state, as in the seal pack 3 on the right side of Fig. 2, where the compression deformation was ignored. In fact, the sealing packing 3 is in the attached state, as in Fig. 2 shown on the left, pressed against the contact surface 43a of the peripheral wall 43 and compressed.

[0028] As in Fig. 5, the anchor portions 31 engage in the plurality of through-holes 21, and their sectional shape in the radial direction is T-shaped. The anchor portions 31 of the present embodiment are formed by round disc-shaped synthetic resin cured on the upper surface of the bottom portion 20a (outer surface) and by synthetic resin cured in the through-holes 21. At the positions of the six anchor portions 31 of Fig. 4, through holes 21 (not shown) are formed. The diameter of the round, disc-shaped synthetic resin is larger than the diameter of the through holes 21.

[0029] As in Fig. 5, the protruding portion 32 serves to close a gap between the protruding portion 30 and the inner wall 20c of the recessed portion 20, and is provided between the at least several anchor portions 31 of the recessed portion 20. As stated above, when the resin forming the protruding portion 30 is demolded after filling the resin in the outsert molding before it is fully cured, the resin tends to contract radially inward. The protruding portion 32 is a member that counteracts this contraction force and ensures that the position of the protruding portion 30 does not deviate radially from the original position.The protruding portion 32 of the present embodiment, like the protruding portion 30, is provided around the entire circumference in the recessed portion 20 and closely adheres to the inner surfaces of the bottom portion 20a and the inner wall 20c.

[0030] A height dimension H of the protruding portion 32 (vertical length from the bottom portion 20a) is set to provide a space that leaves the press-deformation amount of the protruding portion 30. In the packing 3, in the mounted state, the protruding portion 30 is pressed against the pressing surface 43a and press-deformed, as shown in Fig. 2 shown on the left. Thus, as in Fig. 2, a volume corresponding to the interference part between the front end portion of the protrusion portion 30 and the end portion of the peripheral wall 43 (press deformation amount) can move radially inward, a space is required on the radially inner side of the protrusion portion 30 so as not to hinder this movement. Therefore, the height dimension H of the protrusion portion 32 is determined taking into account the press deformation of the protrusion portion 30 in the attached state. If the height dimension H of the protrusion portion 32 is too small, this may result in insufficient strength, and therefore it is set to at least 1 / 3 and at most 1 / 2 of the protrusion dimension P of the protrusion portion 30. More preferably, the height dimension H is set to approximately half of the protrusion dimension P, as shown in Fig. 5 shown.

[0031] A gap is provided between the protrusion portion 30 and the outer wall 20b of the recessed portion 20, into which the end wall 43b of the peripheral wall 43 is inserted. In other words, an abutment surface 20d is provided in the recessed portion 20 on the opposite side of the protruding portion 32 (outer side in the radial direction) from the protrusion portion 30, against which the end surface of the peripheral wall 43 abuts. The abutment surface 20d is a part of the inner surface of the bottom portion 20a that is located farther outward in the radial direction than the protrusion portion 30. By abutting the end surface of the peripheral wall 43 of the transmission housing 4 against the abutment surface 20d, the transmission housing 4 and the transmission cover 2 are positioned in the axial direction. Further, by inserting the end wall 43b into the gap, the transmission cover 2 is positioned in the radial direction. 2. Effect (1) According to the disclosed sealing structure, the protruding portion 32, which closes the gap between the protruding portion 30 and the inner wall 20c of the recessed portion 20, can stabilize the position of the protruding portion 30 between adjacent anchor portions 31 in the radial direction, since it is provided at least between the anchor portions 31. Since bending of the protruding portion 30 in the circumferential direction can be prevented in this way, the sealing performance can be enhanced. (2) In the above-mentioned sealing structure, the protruding portion 32 is provided as a part of the packing 3. That is, the protruding portion 32 is provided integrally with the protrusion portion 30 and the anchor portions 31 by outsert molding, therefore, the protruding portion 32 can be easily formed and the manufacturing cost can be kept low. (3) Since the protruding portion 32 is provided in the recessed portion 20 around the entire circumference, the position of the packing 3 in the radial direction can be further stabilized, whereby the sealing performance can be further increased. (4) Since the height dimension H of the protruding portion 32 from the bottom portion 20a is set to provide a space that allows for the press deformation amount of the protruding portion 30, the protruding portion 30 is not obstructed in the mounting state. Therefore, the position of the protruding portion 30 in the radial direction can be fixed, and at the same time, the sealing performance can be improved. (5) In addition, if the height dimension H of the protruding portion 32 is at least 1 / 3 of the protrusion dimension P of the protrusion portion 30, the strength of the protruding portion 32 can be ensured, and the position of the protrusion portion 30 in the radial direction can be fixed. Furthermore, if the height dimension H is at most 1 / 2 of the protrusion dimension P, the space for the protrusion portion 30 can be reliably left free. (6) As mentioned above, in the case of a round outer shape of the gear cover 2, six through holes 21 (i.e., anchor portions 31) are arranged at equal intervals in the circumferential direction so that the packing 3 can be securely fixed to the gear cover 2. By using every other of the six through holes 21, i.e., a total of three through holes 21, as a gate, both better flow of the resin can be achieved and utilization can be optimized (the amount of resin curing in passages such as gates or sprues can be minimized). In this way, costs can be kept low while the quality of the packing 3 is improved. (7) In the sealing structure described above, the abutment surface 20d against which the end surface of the peripheral wall 43 abuts is provided in the recessed portion 20 on the opposite side of the protruding portion 32 with respect to the protruding portion 30, whereby the transmission cover 2 can be positioned in the axial direction with respect to the transmission case 4. Further, by inserting the end wall 43b of the peripheral wall 43 into the gap between the protruding portion 30 and the outer wall 20b of the recessed portion 20, the transmission cover 2 can be positioned in the radial direction with respect to the transmission case 4. (8) In the above-described motor 1, by applying the above-described sealing structure to the sealing portion between the gear case 4, which houses the reduction mechanism 13, and the gear cover 2, the sealing performance can be improved. By integrally forming the gear cover 2 and the seal packing 3, it is possible to handle them as one component rather than as separate components, and to reduce the number of components, thereby improving the assembly efficiency when the motor 1 is automatically assembled by an automatic machine. Compared with providing the seal packing separately, with the above-described sealing structure, there is no risk of the seal packing being displaced during assembly, thereby improving the quality of the motor 1. 3. Miscellaneous

[0032] The sealing structure of the embodiment described above is merely a non-limiting example.

[0033] For example, it is sufficient if the protruding portion 32 is provided at least between adjacent anchor portions 31 without extending around the entire circumference. It is also sufficient if the protruding portion 32 closes the gap between the protruding portion 30 and the inner wall 20c of the recessed portion 20, and it may also be provided separately from the packing 3. If the protruding portion is provided separately from the packing 3, the protruding portion may be formed of a different material than the packing 3. Alternatively, the protruding portion may also be formed integrally with the packing 2, adapting the shape of the transmission cover 2. The height dimension H of the protruding portion 32 may also be set appropriately.

[0034] The specific shape of the sealing packing 3 is not limited to the above description, and the front end of the protrusion portion 30, for example, does not need to be semicircular. It is also sufficient if the anchor portions 31 are shaped in such a way that they fix the sealing packing 3 to the transmission cover 2 by engaging with the through holes 21, and there is no limitation to the shape described above.

[0035] The specific shape of the transmission cover 2 is also not limited to the above-described shape. For example, the number of through holes 21 (anchor portions 31) or the number of gates is not limited to the above-described number, but can be determined as appropriate. The outer shape of the transmission cover 2 can also be modified as appropriate to adapt to the shape of the opening portion 40 of the transmission housing 4. Furthermore, the method for fixing the transmission cover 2 to the transmission housing 4 is not limited to caulking.

[0036] The above embodiment was described using the example of a sealing structure applied to a sealing portion between a gear case 4, in which a reduction mechanism 13 of a motor 1 is housed, and a gear cover 2. However, the above-described sealing structure can also be applied to sealing portions other than the above-described sealing portion. For example, the sealing structure can be applied to a motor that does not have a reduction mechanism 13.That is, a sealing structure may also be formed wherein, at a sealing portion of a casing (housing) accommodating a rotor and a stator and an end cap (cover) closing an opening of the casing, a recessed portion and through holes are provided on the end cap, and a sealing member having a projection portion and anchor portions is provided integrally with the end cap, and a projecting portion is further provided.

[0037] The sealing structure described above can also be applied to a sealing portion of a housing that accommodates components other than a motor and a cover that closes an opening portion of the housing. Explanation of reference symbols 1 motor (motor with reduction gear) 10 engine bodies 11 Enclosure 11a Flange section 12 Wave 13 Reduction mechanism 13A snail 13B Worm gear (component) 14 Output gear 15 step section 16 O-ring 2 Gearbox cover (cover) 20 recesses 20a floor section 20b exterior wall 20c interior wall 20d contact surface 20th final section 20f exterior surface 20g inner surface 21 through hole 22 output hole 23 vertical wall 3 Sealing packing (sealing element) 30 projection section 31 anchor section 32 preceding section 4 Gearbox housing (housing) 40 opening section 41 first recording section 42 second recording section 43 Perimeter wall 43a Contact surface 43b End wall 44 Connection opening 45 sub-section 46 Bearing shaft 47 connecting section 5 Upper tool 5a first cavity 6 Lower tool 7 Cut 90 projection section 91 anchor section P projection from the floor section H Height dimension from the floor section

Claims

[1] A sealing structure for sealing between a cover (2) for closing an opening portion of a housing (4) in which components are accommodated and the housing (4) by means of a sealing element (3), wherein the cover (2) has an annular recessed portion (20) attached to an end portion of a peripheral wall (43) forming the opening portion of the housing (4), wherein the sealing element (3) is formed integrally with the cover (2) and integrally has a projection portion (30) formed in the recessed portion (20) around the entire circumference from a bottom portion (20a) of the recessed portion (20), characterized byin that the cover (2) has a plurality of through-holes (21) which run through the bottom section (20a) of the recessed section (20) and are spaced apart from one another in the circumferential direction, the sealing element (3) has a plurality of anchor sections (31) in one piece which engage in the through-holes (21) and fix the sealing element (3) to the cover (2), between at least a plurality of anchor sections (31) in the recessed section (20) a projecting section (32) is provided which closes a gap between the projecting section (30) and an inner wall (20c) of the recessed section (20), and in the recessed section (20) on the side of the projecting section (32) opposite to the projecting section (30) a contact surface (20d) is provided against which an end surface of the peripheral wall (43) of the housing (4) rests. [2] Sealing structure according to claim 1, characterized bythat the projecting portion (32) is provided integrally with the sealing element (3) by means of outsert molding. [3] Sealing structure according to claim 1 or 2, characterized by that the projecting portion (32) is provided in the recessed portion (20) around the entire circumference. [4] Sealing structure according to one of claims 1-3, characterized by that the height of the projection of the projection portion (30) from the bottom portion (20a) is set such that, in an attached state of the housing (4) and the cover (2), press deformation takes place by the end portion of the peripheral wall (43), and a height dimension of the projecting portion (32) from the bottom portion (20a) is set such that a space is provided which leaves the press deformation amount of the projection portion (30). [5] Sealing structure according to claim 4, characterized bythat the height dimension of the projecting portion (32) is at least 1 / 3 and at most 1 / 2 of the projection dimension of the projecting portion (30). [6] Sealing structure according to one of claims 1-5, characterized by in that the cover (2) has a round outer shape and six through holes (21) which are arranged at equal intervals in the circumferential direction of the recessed section (20), wherein every second through hole (21), a total of three of the six through holes (21), have the function of a gate. [7] A motor (1) with a reduction gear, comprising a motor section (10) having a rotor and a stator, and a reduction mechanism (13) having a worm (13A) to which rotation of the motor section (10) is transmitted, and a worm wheel (13B) in engagement with the worm (13A), wherein a sealing section of a gear case (4) accommodating the reduction mechanism (13) and a gear cover (2) attached to the gear case (4) use a sealing structure according to any one of claims 1-6.

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