spherical worm wheel

Abstract

The present disclosure relates to a spherical worm wheel (4) for engagement with a worm (3) in a worm gear assembly (1). The spherical worm wheel (4) comprises a first and a second side surface (17, 18), a peripheral surface (10) and an axis of rotation. The spherical worm wheel (4) further comprises a plurality of gear teeth (9) spaced apart around the peripheral surface (10) with a gap (11) between adjacent gear teeth (9), the plurality of gear teeth (9) being configured to engage with the worm (3). The plurality of gear teeth (9) are configured such that the gap (11) between adjacent gear teeth (9) is open to the first side surface (17).

Description

Technical Field

[0001] The present invention relates to a spherical worm wheel for meshing with a worm in a worm wheel assembly, and to a gear assembly including a spherical worm wheel and a worm. Background Technology

[0002] The spherical worm gear assembly includes a worm and a spherical worm gear that rotates through the worm. The worm includes one or more helical gear teeth that mesh with the gear teeth of the spherical worm gear to transmit rotational motion. The worm and the spherical worm gear rotate about a vertical axis of rotation.

[0003] Compared to conventional worm gears, spherical worm gears are shaped to increase the surface area of ​​their gear teeth. This provides reduced contact pressure and an increased number of meshing gear teeth, which reduces gear wear and increases the transmittable torque.

[0004] The assembly of this spherical worm gear assembly is limited because the worm cannot be assembled on the housing before the spherical worm gear, and the spherical worm gear cannot mesh with the worm by moving it into the housing in the axial direction due to the interference between the worm and the spherical worm gear. Summary of the Invention

[0005] According to the present invention, a spherical worm gear is provided for meshing with a worm in a worm gear assembly. The spherical worm gear includes a first side surface and a second side surface, a peripheral surface, and a rotation axis. The spherical worm gear also includes a plurality of gear teeth spaced apart around the peripheral surface, with gaps between adjacent gear teeth, the plurality of gear teeth being configured to mesh with the worm. The plurality of gear teeth are configured such that the gaps between adjacent gear teeth open toward the first side surface. This spherical worm gear may be referred to as an open or semi-open spherical worm gear.

[0006] In the example, the edges of the plurality of gear teeth on the first side surface all include chamfers. Additionally or alternatively, the edges of the clearances on the first side surface all include chamfers. In particular, the edges of the first side surface may include chamfers that encompass the edges of the plurality of gear teeth on the first side surface and the edges of the clearances on the first side surface.

[0007] A worm gear assembly is also provided, comprising the aforementioned spherical worm gear, worm, and housing, the housing including a recess shaped to receive the spherical worm gear. The spherical worm gear and worm are mounted to the housing to rotate about a vertical axis of rotation, such that the worm meshes with the gear teeth of the spherical worm gear.

[0008] A method for assembling a worm gear assembly is also provided. The method includes: mounting a worm to a housing; and then mounting a spherical worm gear to the housing by inserting it into a recess along the axial direction of the spherical worm gear. Specifically, the method includes inserting an open or semi-open spherical worm gear into the recess along the axial direction of the spherical worm gear. Attached Figure Description

[0009] Example embodiments of the invention are illustrated in the accompanying drawings, in which:

[0010] Figure 1 A 3D view of the worm gear assembly is shown;

[0011] Figure 2 Showing Figure 1 A 3D view of the worm gear assembly during assembly;

[0012] Figure 3A Showing Figure 1 The spherical worm of the worm gear assembly;

[0013] Figure 3B Showing Figure 1 The conventional worm gear of the worm gear assembly;

[0014] Figure 4 Showing Figure 1 The first example of a spherical worm gear assembly;

[0015] Figure 5 Showing Figure 1 A second example of a spherical worm gear assembly;

[0016] Figure 6 Showing Figure 1 The third example of a worm gear assembly is a spherical worm gear;

[0017] Figure 7 Showing Figure 1 The fourth example of a spherical worm gear assembly;

[0018] Figure 8 Showing Figure 1 An example spherical worm gear assembly is shown, which illustrates the contact surface with the spherical worm.

[0019] Figure 9 Showing Figure 1 The shear stress distribution of the gear teeth in an example spherical worm gear assembly; and

[0020] Figure 10 Showing Figure 1 Another example of a worm gear assembly is the shear stress distribution of the gear teeth in a spherical worm gear. Detailed Implementation

[0021] The example embodiment shown relates to a spherical worm gear for meshing with a worm in a worm gear assembly.

[0022] Figure 1 The worm gear assembly 1 shown includes a housing 2, a worm 3, and a spherical worm gear 4. The housing 2 includes a recess 6 in which the spherical worm gear 4 is disposed. The housing 2 also includes a mounting element (7, see [reference]). Figure 2 For example, as shown in the hole, or alternatively a shaft, the spherical worm gear 4 is rotatably mounted to the mounting. The housing 2 also includes mounting portions 5a, 5b for rotatably mounting the worm 3, such that the worm 3 extends across one side of the recess 6. Figure 1 In the assembled state shown, the worm 3 is engaged with the spherical worm wheel 4. The rotation of the worm 3 drives the rotation of the spherical worm wheel 4. The axis of rotation of the worm 3 is perpendicular to the axis of rotation of the spherical worm wheel 4.

[0023] The worm 3 includes one or more helical gear teeth 8 on its peripheral surface. The spherical worm gear 4 includes a plurality of gear teeth 9 arranged to mesh with the helical gear teeth 8 of the worm 3. In particular, as Figure 1 As shown, the mounting bracket (7, see) for the spherical worm gear 4 Figure 2 The mounting portions 5a and 5b for the worm 3 are arranged such that the worm 3 meshes with the spherical worm wheel 4, so that the rotation of the worm 3 drives the rotation of the spherical worm wheel 4.

[0024] like Figure 2 As shown, in the preferred method of assembling the worm gear assembly 1, the worm 3 is mounted to the housing 2, particularly via mounting portions 5a and 5b; then, the spherical worm gear 4 is attached to the housing 2, particularly to the mounting member 7, by inserting the spherical worm gear 4 into the recess 6 along its axial direction. The spherical worm gear 4 can be pressed into the recess 6.

[0025] As shown in the figure, the recess 6 is preferably configured to tightly surround the peripheral surface of the spherical worm gear 4, wherein there is only a small gap between the surface of the recess 6 and the gear teeth 9 of the spherical worm gear 4. In particular, the recess 6 is cylindrical and has an opening at one end to receive the worm 3.

[0026] In an alternative example, the worm 3 may be rotatably mounted to the housing 2 at a single mounting point (e.g., mounting point 5a). As shown, the spherical worm gear 4 may include a pin or shaft that engages with a mounting member 7 in the form of a hole, or the mounting member 7 of the housing 2 may include a shaft or pin for mounting the spherical worm gear 4. The housing 2 may include two parts, with the worm 3 assembled between these two parts to facilitate the assembly of the housing 2 and the worm 3.

[0027] The worm gear assembly 1 may include one or more bearings or bushings for the worm 3 and / or the spherical worm gear 4. Alternatively, the housing 2 and / or the shaft or pin of the worm 3 and / or the spherical worm gear 4 may include a low-friction or self-lubricating material, such as polyamide (e.g., nylon) or polyoxymethylene. In some examples, the spherical worm gear 4 may be made of a self-lubricating material, such as polyamide (e.g., nylon) or polyoxymethylene.

[0028] In the final configuration, the spherical worm gear 4 is connected to another component (not shown) such that when the worm 3 rotates, this other component rotates via the spherical worm gear 4. For example, the spherical worm gear 4 can be connected to a windshield wiper to actuate the windshield wiper, or to a window lift system to open and close the window. Therefore, the worm gear assembly 1 can be an automotive worm gear assembly.

[0029] Figure 3A A first example of the worm 3 of the worm gear assembly 1 is shown. In this example, the worm 3 is a spherical worm 3. The spherical worm 3 includes one or more helical gear teeth 8, such as one, two, or three helical gear teeth 8, on its peripheral surface 12. Compared with a conventional worm (see...), Figure 3B In contrast, the depth of the helical gear teeth 8 of the spherical worm gear 3 varies along the length of the spherical worm gear 3. Specifically, the depth 13 of the helical gear teeth 8 is greater at the end 15 of the helical gear teeth 8 than at the center 16 of the helical gear teeth. In this way, the helical gear teeth 8 conform to the periphery of the spherical worm gear 4 to increase the contact surface area between the helical gear teeth 8 and the gear teeth 9 of the spherical worm gear 4. Furthermore, as shown in the figure, the diameter of the shaft 14 of the spherical worm gear 3 (from which the helical gear teeth 8 protrude) can be reduced at the center 16 in the same manner.

[0030] Figure 3B An alternative example of the worm 3 of the worm gear assembly 1 is shown. In this example, the worm 3 is a conventional worm 3. The conventional worm 3 includes one or more helical gear teeth 8, such as one, two, or three helical gear teeth 8, on its peripheral surface 12. Compared to a spherical worm (see Figure 3a), the depth of the helical gear teeth 8 of the conventional worm 3 remains constant along the length of the conventional worm 3.

[0031] It should be understood that, Figure 1 The worm gear assembly 1 shown may use a spherical worm 3 (see...). Figure 3A ) or conventional worm gear 3 (see Figure 3B Preferably, the worm gear 3 is as follows: Figure 3B The conventional worm gear 3 shown is because the conventional worm gear 3 is more advanced than a spherical worm gear (such as...). Figure 3A (What is shown) is easier to manufacture and cheaper.

[0032] Figures 4 to 7Different examples of the spherical worm gear 4 used in the aforementioned worm gear assembly 1 are shown. Figures 4 to 7 In each example, the spherical worm gear 4 includes a first surface 17 and a second surface 18, particularly a front surface 17 and a rear surface 18. The spherical worm gear 4 also includes a peripheral surface 10 extending between the first surface 17 and the second surface 18. The spherical worm gear 4 includes a plurality of gear teeth 9 spaced apart around the peripheral surface 10 of the spherical worm gear 4. A gap 11 is provided between the gear teeth 9.

[0033] exist Figure 4 In the example, each gap 11 extends both to the front surface 17 and the rear surface 18 of the spherical worm gear 4, such that the gap 11 is open to both the front surface 17 and the rear surface 18. This allows the spherical worm gear 4 to mesh with the worm 3 by moving it in the axial direction, as... Figure 2 As shown. In particular, since the gap 11 is open to the front surface 17 and the rear surface 18, the helical gear teeth 8 of the worm 3 can enter the gap 11 between the gear teeth 9 as the spherical worm wheel 4 moves axially.

[0034] Another advantage of the gap 11 that opens to the surface 17 and the rear surface 18 is that the spherical worm gear 4 can be molded more easily, especially by injection molding, because forming the gear teeth 9 around the peripheral surface 10 requires fewer sliding cores.

[0035] For example Figure 4 As shown, each gear tooth 9 has a top surface 19 including a recess 20. The recess 20 is centrally located in the gear tooth 9 and is configured to align with and accommodate the shaft 14 of the worm 3 (see [link to diagram]). Figure 3A and Figure 3B This allows the worm 3 and the spherical worm wheel 4 to be closer together, thereby increasing the contact surface area between the helical gear teeth 8 of the worm 3 and the gear teeth 9 of the spherical worm wheel 4.

[0036] For example Figure 4 As shown, preferably, the tooth width 21 (i.e., the thickness of the tooth 9 in the circumferential direction) of each gear tooth 9 is thinner at the center than at the positions of the two opposing surfaces 17, 18 facing the spherical worm gear 4. In particular, the side surface 22 of each gear tooth 9 is concave. This configuration increases the contact surface area between the helical gear teeth 8 of the worm 3 and the gear teeth 9 of the spherical worm gear 4.

[0037] exist Figure 5In the example, the spherical worm gear 4 includes a flange 23 on its rear end 18. The flange 23 may be an integral part of the spherical worm gear 4 or attached to it. Thus, the clearance 11 between the gear teeth 9 is not open to the rear end 18 of the spherical worm gear 4. However, the clearance 11 between the gear teeth 9 is open to the front end 17 of the spherical worm gear 4, thereby allowing the spherical worm gear 4 to be axially assembled into the housing 2 through the front end 17, as shown in the reference. Figure 2 As stated above.

[0038] exist Figure 5 In the example, when the gap 11 is closed on one side by the flange 23, the spherical worm gear 4 is a hemispherical worm gear.

[0039] like Figure 5 As shown, the root surface 24 in the gap 11 between the gear teeth 9 bends upward toward the flange 23 (i.e., bends in a radially outward direction). The flange 23 and the bent root surface 24 increase the strength of the gear teeth 9.

[0040] exist Figure 5 In the example, gear tooth 9 has a reference Figure 4 The recess 20 and concave side surface 22 are described. However, it should be understood that each of these features may be used in combination with the flange 23 and the curved tooth root surface 24.

[0041] exist Figure 6 In the example, the leading edge 27 of the spherical worm gear 4 has a chamfer 26. Specifically, the leading edge 25 of each gear tooth 9 includes a chamfer 26 that gradually decreases towards the leading surface 17 of the spherical worm gear 4. Additionally or alternatively, the edges of the clearance 11 at the leading surface 17 also include chamfers 26 that gradually decrease towards the leading surface 17 of the spherical worm gear 4. Figure 2 As shown, the chamfer 26 makes it easier for the spherical worm gear 4 to mesh with the worm 3 during the assembly of the gear assembly 1. Specifically, the chamfer 26 guides the helical gear teeth 8 of the worm 3 into the gap 11 between the gear teeth 9, and as... Figure 2 As shown, as the spherical worm gear 4 is pressed into the housing 2, the gear teeth 9 can also be additionally deformed to allow the helical gear teeth 8 to enter the gap 11.

[0042] Preferably, the gear teeth 9 (particularly the side surfaces 22), clearance 11, and leading edge 27 of the spherical worm gear 4 are configured such that the helical gear teeth 8 of the worm 3 must be pressed into the clearance 11 before engaging with the concave side surfaces 22 of the gear teeth 9, to overcome interference between the helical gear teeth 9 and the gear teeth 9. In this way, the spherical worm gear 4 can be assembled by pressing it into the housing 2 to mesh with the worm 3. Figure 1 The gear assembly 1, and during further assembly operations, this interference prevents the spherical worm gear 4 from becoming dislodged, which may include making... Figure 1The gear assembly 1 shown is reversed. The interference also provides a tight fit between the gear teeth 9 of the spherical worm gear 4 and the helical gear teeth 8 of the worm 3, thereby reducing backlash and increasing the contact surface area during use.

[0043] exist Figure 6 In the example, gear tooth 9 has a reference Figure 4 The recess 20 and concave side surface 22 are described. However, it should be understood that each of these features may optionally be used in combination with the chamfer 26. Furthermore, refer to... Figure 5 The described spherical worm gear 4 may additionally include Figure 6 The chamfer shown is 26.

[0044] exist Figure 7 In the example, the top surface 19 of each gear tooth 9 includes a first portion 32 adjacent to the front 17 and a second portion 28 adjacent to the rear 18. The second portion 28 has a larger diameter than the first portion 32, thereby forming a step or preferably a ramp 29 between the first portion 32 and the second portion 28.

[0045] The smaller diameter of the first part 32 allows the spherical worm gear 4 and the worm 3, as well as the housing 2, to be referenced. Figure 2 The aforementioned method involves axial assembly. Specifically, the smaller diameter of the first portion 32 reduces or eliminates interference between the helical gear teeth 8 of the worm 3 and the gear teeth 9 of the spherical worm wheel 4 (which could otherwise prevent the helical gear teeth 8 from engaging in the clearance 11), and also allows the shaft 14 of the worm 3 to move into place. The second portion 28 provides a larger contact surface area between the helical gear teeth 8 of the worm 3 and the gear teeth 9 of the spherical worm wheel 4. This increases the contact surface area and improves torque transmission, and also increases the stiffness of the gear teeth 9.

[0046] In some examples, the first part 32 can be found in the reference. Figure 4 The recess 20 is described at its diameter, thus eliminating the need for a recess 20. In such an example, the spherical worm gear 4 is a hemispherical worm gear. Alternatively, Figure 7 The example gear tooth 9 may additionally include a recess 20, such as in reference Figure 4 The recesses described.

[0047] exist Figure 7 In the example, gear tooth 9 may optionally include a reference. Figure 4 The concave side surface 22 is described. Additionally or alternatively, the spherical worm gear 4 may include a reference... Figure 5 The described flange 23 and / or the curved tooth root surface 24, and / or reference Figure 6 The described chamfer is 26.

[0048] Figure 8Example spherical worm gear 4 is shown, and instructions are given. Figure 1 The contact point of the helical gear teeth 8 of the worm 3 in the gear assembly shown. As shown, the spherical worm gear 4 includes gear teeth 9, which include concave side surfaces 22 and chamfers 26 located on the leading edge 27, as referenced. Figure 4 and Figure 6 As described.

[0049] like Figure 8 As shown, the concave side surface 22 meshes with the helical gear teeth 8 across the concave portion of the side surface 22. Figure 8 As shown, region 31 of gear tooth 9 meshes with helical gear tooth 8 of worm 3.

[0050] In this example, all four gear teeth 9 mesh simultaneously, and at maximum engagement (gear tooth 9a as indicated in the figure), almost the entire concave portion of the side surface 22 is engaged. Therefore, the concave side surface 22 of the gear teeth 9 increases the contact surface area between the helical gear teeth 8 of the worm 3 and the gear teeth 9 of the spherical worm wheel 4, which improves torque transmission.

[0051] Figure 9 Shown in Figure 5 The gear tooth section of the spherical worm gear 4 subjected to shear stress 30 in the gear tooth 9. Figure 10 Shown in Figure 6 The gear tooth section of the spherical worm gear 4 subjected to shear stress 30 in the gear tooth 9.

[0052] As shown in the figure, with Figure 5 Compared to the hemispherical worm gear 4, in Figure 6 In the spherical worm gear 4, the shear stress is distributed over a larger surface area 30. The increased surface area 30 on which the shear force is distributed reduces the maximum shear stress on each gear tooth 9 and extends the life of the spherical worm gear 4.

[0053] Preferably, the gear teeth 9 of the spherical worm gear 4 are helical, although the helix angle is very small.

[0054] In summary, a spherical worm gear 4 is provided for meshing with a spherical worm 3 in a worm gear assembly 1. The spherical worm gear 4 has a first side surface 17 and a second side surface 18, a peripheral surface 10, and a rotation axis. The spherical worm gear 4 also includes a plurality of gear teeth 9 spaced apart around the peripheral surface 10, with gaps 11 arranged between adjacent gear teeth 9. The plurality of gear teeth 9 are configured to mesh with the spherical worm 3. The plurality of gear teeth 9 are configured such that the gaps 11 between adjacent gear teeth 9 are open to the first side surface 17.

[0055] A worm gear assembly including a spherical worm gear 4 is also provided. The worm gear assembly 1 includes a housing 2, a spherical worm 3, and a spherical worm gear 4. The spherical worm gear 4 and the spherical worm 3 are mounted to the housing 2 to rotate about a vertical axis of rotation, and the spherical worm 3 meshes with the gear teeth 9 of the spherical worm gear 4.

[0056] A method for assembling the aforementioned worm gear assembly 1 is also provided. The method includes: firstly, mounting the worm 3 to the housing 2; then, mounting the spherical worm gear 4 to the housing 2 by inserting it into the recess 6 along its axial direction. As the spherical worm gear 4 is inserted into the housing 2, the gear teeth 9 of the spherical worm gear 4 mesh with one or more gear teeth of the worm 3.

Claims

1. A spherical worm wheel (4) for meshing with a worm (3) in a worm wheel assembly (1), the spherical worm wheel (4) comprising: The first side surface (17) and the second side surface (18), the peripheral surface (10) and the first axis of rotation; as well as Multiple gear teeth (9) are spaced apart around the peripheral surface (10), with gaps (11) between adjacent gear teeth (9), and the multiple gear teeth (9) are configured to mesh with the worm (3); The plurality of gear teeth (9) include the gap (11) between adjacent gear teeth (9), the gap (11) being open to the first side surface (17). Among them, the front ends (25) of the plurality of gear teeth (9) at the first side surface (17) all include chamfers (26), and the chamfers (26) gradually decrease in size towards the first side surface (17), and The peripheral surface (10) includes a chamfer (26) at each edge of the gap (11) located on the first side surface (17), the chamfer (26) gradually decreasing towards the first side surface (17) of the spherical worm gear (4).

2. The spherical worm gear (4) as described in claim 1, wherein, Each of the plurality of gear teeth (9) includes a concave side surface (22) for meshing with the worm (3).

3. The spherical worm gear (4) as described in claim 1, wherein, The gap (11) between adjacent gear teeth (9) extends to the second side surface (18).

4. The spherical worm gear (4) as described in claim 1, wherein, The gap (11) between adjacent gear teeth (9) extends only to the first side surface (17), and the second side surface (18) includes a flange (23) that closes the end of the gap (11) between adjacent gear teeth (9).

5. The spherical worm gear (4) as described in claim 4, wherein, The tooth root surface (24) is arranged between every two adjacent gear teeth (9), and the tooth root surface is bent toward the flange (23) in a radially outward direction along the spherical worm gear (4).

6. The spherical worm gear (4) as described in claim 4, wherein, Each of the plurality of gear teeth (9) includes a top surface (19), wherein each top surface (19) includes a first portion (32) adjacent to the first side surface (17) and a second portion (28) adjacent to the second side surface (18), and wherein the radius of the second portion (28) from the first rotation axis is greater than the radius of the first portion (32) from the first rotation axis.

7. The spherical worm gear (4) as described in claim 1, wherein, Each gear tooth (9) has a top surface (19) including a recess (20), wherein the recess (20) is centrally arranged in the gear tooth (9) and is configured to align with and accommodate the shaft (14) of the worm (3).

8. A worm gear assembly (1), the worm gear assembly comprising a spherical worm gear (4) as claimed in claim 1, a worm (3) and a housing (2), the housing including a recess (6) receiving the spherical worm gear (4), and wherein, The spherical worm gear (4) and the worm (3) are mounted to the housing (2) to rotate about a vertical axis of rotation, and the worm (3) meshes with the gear teeth (9) of the spherical worm gear (4).

9. A method of assembling the worm gear assembly (1) as claimed in claim 8, the method comprising: The worm (3) is installed into the housing (2); then the spherical worm wheel (4) is installed into the housing (2) by inserting the spherical worm wheel (4) into the recess (6) along the axial direction of the spherical worm wheel (4).

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