Worm and rotating equipment

Abstract

The present invention relates to a worm and a rotating device. The worm (40) involved in the embodiment is a resin worm formed by injection molding. The worm comprises: a gear portion (40a) having a cavity (40c) with a long axis (40d) of the worm as an axis; and a top portion (40b) formed at an end of one side of the gear portion in the direction of the long axis, with a plurality of recesses (40e) formed at the top portion, the recesses (40e) being closer to the outer peripheral portion of the gear portion than the cavity in the radial direction, and having a hole portion connected to the cavity.

Description

Technical Field

[0001] The invention relates to a worm and a rotating device. Background Art

[0002] Conventionally, there is known a worm gear having a hole that communicates the insertion hole with the outside and releases the air in the insertion hole in order to suppress the shaft from falling out of the insertion hole due to the air compressed in the insertion hole when the shaft is inserted into the insertion hole.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2005-94919

[0004] However, when the worm is manufactured by injection molding of resin, the tip of the pin of the mold for forming the insertion hole of the shaft may not be supported from the radial direction of the shaft. That is, the pin of the mold may be cantilevered and the mold may be molded in a state where the pin of the mold is tilted due to the injection pressure of the resin. If a worm molded in such a state where the pin of the mold is tilted is used, there is a concern that vibration or abnormal noise may be generated when the worm is meshed with a worm wheel or a helical gear. Summary of the invention

[0005] The present invention takes the above as one example of the subject, and an object of the present invention is to provide a worm gear capable of suppressing the generation of vibration or abnormal noise.

[0006] A worm gear according to one embodiment of the present invention is a resin worm gear formed by injection molding. The worm gear comprises: a gear portion having a cavity formed with the long axis of the worm gear as an axis; and a top portion formed at one end of the gear portion in the direction of the long axis, wherein a plurality of recesses are formed in the top portion, the recesses being closer to the outer peripheral portion of the gear portion than the cavity in the radial direction and having a hole portion communicating with the cavity. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is a top view of the rotating device involved in the embodiment.

[0008] Figure 2 It is a bottom view of the rotating device involved in the embodiment.

[0009] Figure 3 This is a perspective view of the rotating device according to the embodiment with the first housing removed.

[0010] Figure 4 It is a top view of the rotating device according to the embodiment with the first housing removed.

[0011] Figure 5 It is a three-dimensional diagram of the worm.

[0012] Figure 6 This is a front view of the worm as seen from the tip side.

[0013] Figure 7 yes Figure 4 VII-VII sectional view.

[0014] Figure 8 It is a perspective view showing a part of the cross section of the worm.

[0015] Fig. 9A This is a diagram for explaining a method of forming a worm (Part 1).

[0016] Fig. 9B This is a diagram for explaining a method for forming a worm (part 2).

[0017] Fig. 9C This is a diagram for explaining the method of forming a worm (part 3).

[0018] Fig.9D This is a diagram (part 4) for explaining the method of forming a worm gear.

[0019] Fig.10 It is a figure which shows the molding method of the worm which concerns on a comparative example.

[0020] Fig.11 It is a figure which shows another forming method of a worm gear.

[0021] Fig.12 yes Fig.11 XII-XII sectional view. DETAILED DESCRIPTION

[0022] Hereinafter, a worm and a motor according to an embodiment will be described with reference to the drawings. The worm according to the embodiment is provided in the motor. In addition, the motor is provided in a rotating device.

[0023] In addition, the use of the worm and the motor is not limited to the embodiments described below. In addition, it should be noted that the drawings are schematic, and the dimensional relationship of each element, the ratio of each element, etc. may be different from the actual. In addition, the drawings may sometimes contain parts with different dimensional relationships and ratios.

[0024] Reference Figure 1 to Figure 4 The rotating device 1 according to the embodiment will be described. Figure 1 It is a top view of the rotating device 1 according to the embodiment. Figure 2 It is a bottom view of the rotating device 1 according to the embodiment. Figure 3 This is a perspective view of the rotary device 1 according to the embodiment with the first housing 2A removed. Figure 4 It is a plan view of the rotary device 1 according to the embodiment with the first housing 2A removed.

[0025] The rotary device 1 can be preferably used as an actuator used in, for example, a vehicle air conditioning system, and can control the rotational motion of a louver for controlling air volume or the like.

[0026] The rotary device 1 includes a housing 2 , a motor 3 , a gear train 4 (gear mechanism), and a rotation angle detection sensor 5 .

[0027] The housing 2 includes a first housing 2A and a second housing 2B. The housing 2 accommodates the motor 3, the gear train 4, and the rotation angle detection sensor 5.

[0028] The first housing 2A includes a first face portion 20 that is a top portion of the housing 2 and a first side wall portion 21 provided on the outer periphery of the first face portion 20. An opening portion (not shown) surrounded by the first side wall portion 21 is formed in the first housing 2A so as to face the first face portion 20. In addition, a first insertion portion 22 into which an external connector (not shown) is inserted is formed in the first side wall portion 21 of the first housing 2A.

[0029] The second housing 2B includes a second face portion 23 serving as the bottom portion of the housing 2 and a second side wall portion 24 provided on the outer periphery of the second face portion 23. The second housing 2B is provided with an opening portion 25 surrounded by the second side wall portion 24 so as to face the second face portion 23. In addition, the second side wall portion 24 of the second housing 2B is provided with a second insertion portion 26 into which an external connector (not shown) is inserted.

[0030] The housing 2 is formed by connecting the first housing 2A and the second housing 2B in a state where the opening of the first housing 2A is butted against the opening 25 of the second housing 2B. The first insertion portion 22 and the second insertion portion 26 are connected to form a connector for accommodating an external connector. The housing 2 is formed of a resin material such as polypropylene, polyethylene terephthalate, or ABS.

[0031] In addition, in the first housing 2A, a plurality of engaging portions 200 extending toward the second housing 2B are integrally formed on the outer periphery of the first side wall portion 21. In addition, an engaging recess 201 is provided in the engaging portion 200. On the other hand, in the second housing 2B, a plurality of protrusions 202 (hereinafter referred to as engaging protrusions 202) corresponding to the plurality of engaging portions 200 of the first housing 2A are integrally formed on the second side wall portion 24. The engaging protrusions 202 engage with the engaging recesses 201 of the engaging portion 200.

[0032] Furthermore, in the present embodiment, the engaging portion 200 is provided in the first housing 2A and the engaging protrusion 202 is provided in the second housing 2B, but the engaging portion may be provided in the second housing 2B and the engaging protrusion may be provided in the first housing 2A.

[0033] In addition, a piece 210 (hereinafter referred to as a joining piece 210) protruding outward is formed at both ends of one side of the first housing 2A and the second housing 2B. The joining piece 210 is provided with a connecting hole 211 for inserting a predetermined fastener (not shown), and the first housing 2A and the second housing 2B are firmly connected via the four connecting holes 211 by the predetermined fastener.

[0034] In the first housing 2A, a cylindrical protrusion 221 having a first through hole 220 through which a fastener (not shown) such as a bolt or a screw can be inserted is formed to protrude from the first surface 20. In addition, the second housing 2B is provided with a second through hole 222 into which the protrusion 221 fits.

[0035] The motor 3 may be a known motor such as a stepping motor or a brushless motor, but is a DC motor in the example shown in the figure, and a worm 40 included in the gear set 4 is mounted on the rotating shaft 311 of the motor 3. Power is supplied to the motor 3 from an external connector via a connection terminal 8 provided at an insertion port 27 formed by a first insertion portion 22 of the first housing 2A and a second insertion portion 26 of the second housing 2B, and a flexible substrate 7.

[0036] The gear train 4 includes a worm 40, a first transmission gear 41, a second transmission gear 42, and an output gear 43 (rotating body). The worm 40 rotates together with the rotating shaft 311 of the motor 3. A top 40b of the worm 40 on the opposite side to the motor 3 is rotatably supported by the second housing 2B.

[0037] The rotation of the worm 40 is transmitted to the helical gear 41a of the first transmission gear 41, and is transmitted to the second transmission gear 42 via the small-diameter gear 41b which is coaxially arranged with the helical gear 41a and has a relatively smaller diameter than the helical gear 41a. Then, the rotation of the second transmission gear 42 is transmitted to the output gear 43. In addition, the output gear 43 is connected to the output shaft 44. The rotation of the motor 3 is decelerated at a predetermined reduction ratio and output to the outside from the output shaft 44.

[0038] In order to control the rotation angle of the output gear 43 , the rotation angle detection sensor 5 detects the rotation angle of the output gear 43 .

[0039] Next, refer to Figures 5 to 8 The worm gear 40 will be described. Figure 5 It is a perspective view of the worm 40 . Figure 6 This is a front view of the worm 40 as seen from the tip end side. Figure 7 yes Figure 4 VII-VII sectional view. Figure 8 It is a perspective view showing a part of the cross section of the worm 40 .

[0040] The worm 40 includes a resin member having an inner peripheral portion 40h in which a cavity (hereinafter referred to as a hole) 40c having a major axis 40d is formed, and an outer peripheral portion 40i in which teeth 40k are formed in a spiral shape. The resin member is cylindrical.

[0041] The major axis 40d becomes the rotating axis 311 when the output shaft 44 of the motor 3 is mounted on the worm 40. In the direction of the major axis 40d, the resin component or the hole 40c has an end 40c1 on one side that is open and an end 40c2 on the other side that is closed (referred to as the end of the gear portion 40a on the opposite side of the motor 3 in the following paragraphs). The axis of the outer peripheral portion 40i is the major axis 40d. In the direction of the major axis 40d, three or more recesses 40e are formed on the outer surface of the end 40c2 of the gear portion 40a on the opposite side of the motor 3 of the resin component. These three or more recesses 40e respectively have a hole portion (referred to as a connecting hole in the following paragraphs) 40g connected to the hole 40c.

[0042] The worm 40 is made of resin and formed by, for example, injection molding. The worm 40 includes a gear portion 40a having an inner peripheral portion 40h and an outer peripheral portion 40i having spiral teeth 40k formed thereon, and the other end portion (hereinafter referred to as a top) 40b.

[0043] The gear portion 40a is cylindrical. A hole 40c for mounting the rotating shaft 311 of the motor 3 is formed in the gear portion 40a. The hole 40c is formed coaxially with the long axis 40d of the worm 40. That is, the hole 40c has an end 40c1 on one side of the opening and an end 40c2 of the gear portion 40a on the opposite side of the motor 3. In addition, the hole 40c is formed to a part of the top 40b, but is not formed to the end of the worm 40 on the opposite side of the motor 3 (the end on the other end 40c2 side). That is, the hole 40c does not penetrate the worm 40.

[0044] The top 40b is formed continuously with the gear portion 40a on the side opposite to the motor 3. At the long axis 40d, the end of the top 40b, i.e., the end on the side opposite to the motor 3, is formed into a curved shape (e.g., an arc shape) along the cross section of the long axis 40d. Specifically, the end side of the top 40b is formed into a hemispherical shape. The top 40b has an outer surface that is rotatably supported by the second housing 2B as another component with the circumferential direction as the rotation direction. That is, the worm 40 rotates with the circumferential direction as the rotation direction in a state where the outer surface is in contact with the second housing 2B.

[0045] Three recesses 40e are formed in the top 40b, and the recesses 40e are arranged on the radially outer side (the outer peripheral portion 40i side of the resin member) of the hole 40c of the gear portion 40a, that is, on the radially outer side of the rotating shaft 311 of the motor 3, and are connected to the hole 40c of the gear portion 40a. In addition, the recesses 40e can be multiple.

[0046] The recess 40e is formed to extend along the major axis 40d of the worm 40, that is, the axial direction of the rotating shaft 311 of the motor 3. A communication hole 40g communicating with the hole 40c of the gear part 40a is formed in the wall parts 40f1 and 40f2 of the four wall parts 40f1, 40f2, 40f3, and 40f4 constituting the recess 40e. The communication hole 40g is formed at a position opposite to the hole 40c in the radial direction.

[0047] The recessed portions 40 e are formed at equal intervals along the circumferential direction of the top portion 40 b , that is, along the circumferential direction which is the rotation direction of the worm 40 .

[0048] Next, refer to FIG. 9A to FIG. 9D A method of molding the worm 40 will be described. FIG. 9A to FIG. 9D These are diagrams (part one to part four) for explaining a method for forming the worm 40 .

[0049] The worm 40 is formed by injection molding using a fixed mold 50 , a first movable mold 51 , and a second movable mold 52 .

[0050] The fixed die 50 is provided with a pin 50 a for forming the hole 40 c in a part of the gear portion 40 a and the top portion 40 b .

[0051] A molding surface 51a for forming the outer shape of the gear portion 40a is formed in the first movable die 51. In addition, a hole 51b into which the second movable die 52 is inserted is formed in the first movable die 51.

[0052] The second movable mold 52 has a molding surface 52a for forming the outer shape (outer peripheral portion 40i) of the top portion 40b. In addition, the second movable mold 52 has three protrusions 52b for forming the recessed portion 40e having the communicating hole 40g in the top portion 40b. The protrusions 52b are provided according to the number of the recessed portions 40e.

[0053] In the case of a profiled worm 40, Fig. 9A As shown in FIG. 1 , the first movable mold 51 and the second movable mold 52 are moved to a predetermined molding position while the second movable mold 52 is inserted into the hole 51b of the first movable mold 51. Thus, the fixed mold 50, the first movable mold 51, and the second movable mold 52 form a cavity 55 as a gap for molding the worm 40.

[0054] The three protrusions 52b come into contact with the pins 50a of the fixed mold 50. Thus, the distal end of the second movable mold 52 is supported by the protrusions 52b.

[0055] Then, the heated and molten resin is injected into the cavity 55 at high pressure. Fig. 9BAs shown, the cavity 55 is filled with resin to mold the worm 40. Furthermore, since the pin 50a of the fixed mold 50 is supported by the protrusion 52b, even when the resin is injected at high pressure, the tip of the pin 50a of the fixed mold 50 is suppressed from being bent.

[0056] Then, after allowing the resin to cool, Fig. 9C As shown, the first movable mold 51 and the second movable mold 52 are moved to separate the worm 40 from the fixed mold 50 .

[0057] In addition, for example, the first movable mold 51 is rotated while the second movable mold 52 is fixed, thereby Fig.9D As shown, the worm 40 is taken out from the second movable die 52. The worm 40 is formed with a hole 40c and a communication hole 40g communicating with the hole 40c.

[0058] The worm 40 includes a gear portion 40a having a hole 40c coaxial with a major axis 40d of the worm 40, and a top portion 40b formed at one end of the gear portion 40a at the major axis 40d. The top portion 40b is provided with a recessed portion 40e located radially closer to the outer peripheral portion 40i of the gear portion 40a than the hole 40c, and has a connecting hole 40g connected to the hole 40c.

[0059] Thus, when the worm 40 is injection molded, the pin 50a of the fixed mold 50 can be supported by the protrusion 52b of the second movable mold 52 forming the recess 40e. Therefore, the pin 50a of the fixed mold 50 that forms the hole 40c of the worm 40 for mounting the rotating shaft 311 of the motor 3 can be suppressed from bending during injection molding. Therefore, the worm 40 can improve the accuracy of the hole 40c of the worm 40, and can improve the positional accuracy of the major axis 40d of the worm 40 and the rotating shaft 311 of the motor 3. Such a worm 40 can suppress the generation of vibration or noise when meshing with the helical gear 41a of the first transmission gear 41. In addition, the worm 40 can improve the power transmission efficiency when meshing with the helical gear 41a of the first transmission gear 41.

[0060] In addition, if Fig.10 As shown in FIG. 1 , it is also conceivable to insert the pin 500 a of the fixed mold 500 into the recess 501 a formed in the second movable mold 501 to suppress the deflection of the pin 500 a of the fixed mold 500 . Fig.10 It is a figure which shows the molding method of the worm 400 which concerns on a comparative example.

[0061] However, in this case, the top cannot be formed on the worm 400, and the end of the worm 400 on the opposite side of the motor cannot be supported by, for example, the housing. Therefore, there is a concern that the end of the worm 400 on the opposite side of the motor will bend, causing vibration or noise, and the power transmission efficiency will be reduced.

[0062] In contrast, the worm 40 according to the embodiment can form a top portion 40b on the side opposite to the motor 3, and can rotate with the circumferential direction of the top portion 40b as the rotation direction in a state where the outer surface of the top portion 40b of the worm 40 is in contact with the second housing 2B. Therefore, the worm 40 can suppress the bending of the tip of the worm 40 on the side opposite to the motor 3, suppress the generation of vibration or noise, and improve the power transmission efficiency.

[0063] In addition, the hole 40c of the worm 40 is connected to the outside through the connecting hole 40g of the recessed portion 40e, so that when the rotating shaft 311 of the motor 3 is mounted on the hole 40c of the worm 40, the air in the hole 40c of the worm 40 can be released from the connecting hole 40g. Therefore, the rotating shaft 311 of the motor 3 can be easily mounted on the worm 40.

[0064] Furthermore, recessed portions 40e are formed at equal intervals in the circumferential direction on the top portion 40b.

[0065] Thus, the pin 50a of the fixed mold 50 can be uniformly supported along the circumferential direction of the pin 50a, and the pin 50a of the fixed mold 50 can be suppressed from bending during injection molding. Therefore, the accuracy of the hole 40c of the worm 40 can be improved, and the positional accuracy of the long axis 40d of the worm 40 and the rotating shaft 311 of the motor 3 can be improved. Therefore, when the worm 40 is meshed with the helical gear 41a of the first transmission gear 41, the generation of vibration or noise can be suppressed, and the power transmission efficiency can be improved.

[0066] In addition, if Fig.11 and Fig.12 As shown, the worm 40 may also be formed using a fixed die 60 , a first movable die 61 , a second movable die 62 , and a stopper 63 . Fig.11 It is a figure which shows another forming method of a worm gear. Fig.12 yes Fig.11 XII-XII sectional view.

[0067] In the fixed mold 60, two recessed parts 60b are formed at the tip of the pin 60a. The two recessed parts 60b are formed at the tip of the pin 60a in an opposed manner. That is, the two recessed parts 60b are formed at positions 180 degrees apart in the circumferential direction.

[0068] The second movable mold 62 has two recesses 62a that communicate with the recess 60b of the fixed mold 60 when inserted into the first movable mold 61. That is, the two recesses 62a are formed at positions 180 degrees apart in the circumferential direction.

[0069] Two through holes 61a are formed in the first movable mold 61. The through holes 61a are formed at positions corresponding to the recessed portion 60b of the fixed mold 60 and the recessed portion 62a of the second movable mold 62. The two through holes 61a are formed to face each other.

[0070] The fixed mold 60 , the first movable mold 61 , and the second movable mold 62 are formed with recessed portions 60 b , 62 a and through holes 61 a so that the stopper 63 can be inserted from the outside when the first movable mold 61 and the second movable mold 62 are moved to a predetermined molding position.

[0071] The stopper 63 is inserted into the through hole 61a and engaged with the recesses 60b and 62a. That is, the pin 60a of the fixed mold 60 is fixed by the engagement of the two stoppers 63 with the recess 60b. In this state, the heated and molten resin is injected at high pressure to form the worm 40. In this case, two recesses 40e are formed in the worm 40. In the worm 40, two recesses 40e having a connecting hole 40g connected to the hole 40c are formed at positions 180 degrees apart in the circumferential direction. The connecting hole 40g is formed at a position opposite to the hole 40c in the radial direction.

[0072] The worm 40 molded using such a die can improve the power transmission efficiency and suppress the generation of vibration and noise, similarly to the above-mentioned embodiment.

[0073] In addition, the present invention is not limited to the above-mentioned embodiment. The structure formed by appropriately combining the above-mentioned various constituent elements is also included in the present invention. In addition, further effects and modifications can be easily derived by those skilled in the art. Therefore, the wider aspects of the present invention are not limited to the above-mentioned embodiment, and various changes can be made.

[0074] Description of Reference Numerals

[0075] 1…rotating device; 2…housing; 2A…first housing; 2B…second housing; 3…motor; 4…gear train (gear mechanism); 40…worm; 40a…gear portion; 40b…top; 40c…hole (cavity); 40c1…end portion of the opening; 40c2…end portion of the other closed portion; 40d…long axis; 40e…recess; 40g…connecting hole (hole portion); 40h…inner peripheral portion; 40i…outer peripheral portion; 41a…helical gear; 50…fixed mold; 51…first movable mold; 52…second movable mold; 60…fixed mold; 61…first movable mold; 62…second movable mold; 63…stopper.

Claims

1. A worm gear, which is a resin worm gear formed by injection molding, wherein: A hollow having a long axis of the worm as an axis; and a gear portion having one end portion and another end portion opened in the direction of the long axis, A top portion is formed at the other end of the gear portion in the direction of the long axis. A plurality of recessed portions are formed at the top portion, the recessed portions are located closer to the outer peripheral portion of the gear portion than the cavity in the radial direction, and have a hole portion communicating with the cavity. The plurality of recesses include a plurality of wall portions, The plurality of wall portions include a wall portion extending in the radial direction and a wall portion extending in the direction of the major axis, and the hole portion is formed in the wall portion extending in the direction of the major axis. In the direction of the long axis, the hole portion is provided between the surface of the top portion facing the cavity and the wall portion extending in the radial direction. In the direction of the major axis, the wall portion extending in the radial direction is located on the one end side of the gear portion relative to the surface of the top portion facing the cavity, The hole portion opens from the cavity in a direction toward an outer peripheral portion of the gear portion in a radial direction.

2. The worm according to claim 1, wherein: The top has an outer surface supported by other components, The worm rotates with the circumferential direction of the top portion as a rotation direction in a state where the outer surface is in contact with the other member.

3. The worm according to claim 1 or 2, wherein: The plurality of recesses are formed at equal intervals on the top portion in the circumferential direction.

4. A worm gear, wherein: The worm gear includes a resin component, The resin component has: An inner peripheral portion, forming a cavity having a major axis; and The outer circumference is formed with teeth in a spiral shape. The resin member has one end and the other end of the opening in the direction of the long axis. The axis of the outer peripheral portion is the major axis, In the direction of the long axis, three or more recessed portions are formed on the outer surface of the other end of the resin member. The three or more recesses have holes connected to the cavity. The three or more recesses each include a plurality of wall portions. The plurality of wall portions include a wall portion extending in the radial direction and a wall portion extending in the direction of the major axis. The hole is formed in a wall extending in the direction of the long axis. The hole portion is provided between a surface of the other end portion facing the cavity and a wall portion extending in the radial direction in the direction of the major axis. In the direction of the major axis, the wall portion extending in the radial direction is located on the one end side relative to the surface of the other end facing the cavity, The hole portion opens from the cavity in a direction toward an outer peripheral portion of the resin member in a radial direction.

5. The worm according to claim 4, wherein: The resin component includes the outer surface supported by another component, The worm rotates with the circumferential direction of the resin member as a rotation direction in a state where the outer surface is in contact with the other member.

6. The worm according to claim 4, wherein: The three or more recessed portions are formed at equal intervals in the circumferential direction.

7. A rotating device, wherein: The rotating device comprises a worm according to any one of claims 1 to 6, a gear meshing with the worm, a motor having an output shaft arranged in the cavity, and a housing accommodating the motor, the gear and the worm. The worm rotates with the circumferential direction of the worm as a rotation direction in a state in which the other end of the worm is in contact with the housing.

8. The rotary device according to claim 7, wherein: The hole portion is located at a position opposing an output shaft of the motor in a radial direction.

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