Axial compact tensioner

Abstract

This utility model discloses an axially compact tensioner, aiming to solve the problems of existing tensioners having loose structures, occupying large axial space, and insufficient dust and water protection performance, leading to internal spring corrosion, bearing jamming, and reduced service life. The technical solution includes a pulley, a connecting cover, a swing arm, and a planar spiral torsion spring. One end of the swing arm has a mounting hole, and the other end has an annular shaft hole. A planar spiral torsion spring is placed between the outer wall of the annular shaft hole and the inner wall of the connecting cover. The connecting cover is located on the same side as the pulley and its end face is basically flat. The end face of the swing arm away from the connecting cover is flat. A friction-reducing ring is fitted onto the annular shaft hole of the swing arm, and the open end of the connecting cover contacts the friction-reducing ring to seal the planar spiral torsion spring. A bearing dustproof mechanism is also provided between the pulley and the swing arm. This utility model has a compact structure and small axial dimension, effectively preventing dust and liquid intrusion, significantly improving the reliability and service life of the tensioner, and is suitable for confined spaces such as automobile engine compartments.

Description

Technical Field

[0001] This utility model relates to the field of automotive parts technology, and in particular to an axially compact tensioner for automotive engine transmission systems. Background Technology

[0002] With the development of the automotive industry, the layout of the engine compartment has become increasingly compact, leaving less and less space for accessory drive systems. As a key component in belt drive systems, the tensioner pulley is mainly used to maintain the tension of the belt and ensure the stability of power transmission.

[0003] Existing tensioner structures typically have the following drawbacks:

[0004] Large axial dimension: The pulley and torsion spring mounting base of the traditional tensioner are often located on the two sides, or the difference in height between the two end faces is large, which results in the overall structure occupying a large space in the axial direction, making it difficult to adapt to the narrow layout environment of modern engine compartments.

[0005] Poor dust and water resistance: The flat spiral torsion spring inside the tensioner pulley is the core component that provides preload, and it is highly susceptible to corrosion from oil, moisture, and dust in the engine compartment, leading to rust and failure. Furthermore, the bearing at the connection between the pulley and the swing arm lacks an effective sealing structure; impurities entering the bearing can increase rotational resistance or even cause it to seize, severely impacting the service life and operational stability of the tensioner pulley.

[0006] Therefore, there is an urgent need for a tensioning wheel structure that is more compact and has excellent dustproof and waterproof performance. Utility Model Content

[0007] To address the aforementioned problems, the purpose of this invention is to provide an axially compact tensioning wheel, thereby resolving the issues of excessively large axial dimensions and poor dust and water resistance in existing tensioning wheels.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] An axially compact tensioning pulley includes a pulley, a connecting cover, a swing arm, and a planar spiral torsion spring. One end of the swing arm has a mounting hole, and the other end has an annular shaft hole. A bearing is installed in the central hole of the pulley, and the pulley is bolted to the mounting hole. A rotating shaft is installed on the connecting cover, the end of which passes through the annular shaft hole of the swing arm and is screwed to an end cap. A damping ring is also provided between the end cap and the swing arm. A planar spiral torsion spring is provided between the outer wall of the annular shaft hole and the inner wall of the connecting cover. The connecting cover and the pulley are located on the same side, with the outward-facing end face of the connecting cover and the outward-facing end face of the pulley being flush or nearly flush. The other end face of the swing arm, away from the connecting cover and the pulley, is flat. A friction-reducing ring is fitted onto the annular shaft hole of the swing arm, and the open end of the connecting cover contacts the friction-reducing ring, thereby sealing the planar spiral torsion spring and preventing dust or liquid from corroding it. A bearing dustproof mechanism is also provided between the pulley and the swing arm.

[0010] Furthermore, the bearing dustproof mechanism includes an annular groove and a dustproof ring disposed on the swing arm. The edge of the annular groove protrudes towards the bearing with a first convex ring. The annular groove covers one end face of the bearing. The first convex ring is close to the end face of the central shaft hole of the pulley. The dustproof ring is sleeved on the bolt and covers the other end face of the bearing. The edge of the dustproof ring protrudes towards the bearing with a second convex ring, which is close to the end face of the central shaft hole of the pulley.

[0011] Furthermore, the central shaft hole of the pulley is provided with an annular groove, and the outer ring of the bearing is tightly disposed in the annular groove. This structure is mainly completed by injection molding the bearing and the pulley into one piece.

[0012] Furthermore, the wear-resistant ring is made of wear-resistant plastic or copper alloy.

[0013] The beneficial effects of this utility model are as follows:

[0014] 1. By setting the connecting cover and pulley to the same side and with their end faces basically flat, and by utilizing the flat swing arm end face design, the axial thickness of the overall structure is greatly compressed, achieving axial compactness and facilitating installation in narrow spaces.

[0015] 2. By setting the anti-friction ring and the opening end of the connecting cover to cooperate, a closed or semi-closed chamber is formed, which wraps the planar spiral torsion spring inside, effectively blocking the intrusion of external dust and liquid, and protecting the core elastic element.

[0016] 3. The bearing dustproof mechanism forms a labyrinth seal structure through the close engagement of the first and second convex rings with the end face of the pulley's central shaft hole. Combined with the physical barrier of the annular groove and dustproof ring, multiple layers of protection ensure the cleanliness of the bearing's interior, reduce rotational resistance, and extend its service life.

[0017] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0018] Figure 1 This is a perspective view of a specific embodiment of the present utility model;

[0019] Figure 2 This is a cross-sectional view of a specific embodiment of the present utility model;

[0020] Figure 3 for Figure 2 A magnified view of A in the middle.

[0021] Explanation of reference numerals in the attached drawings: 1. Pulley; 2. Connecting cover; 3. Swing arm; 4. Planar spiral torsion spring; 5. Mounting hole; 6. Annular shaft hole; 7. Bearing; 8. Bolt; 9. Rotary shaft; 10. End cover; 11. Damping ring; 12. Anti-friction ring; 13. Bearing dustproof mechanism; 14. Annular groove; 15. Dustproof ring; 16. First convex ring; 17. Second convex ring; 18. Annular groove. Detailed Implementation

[0022] The present invention will be described in detail below through embodiments, which are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention.

[0023] like Figure 1 — Figure 3 As shown, this embodiment discloses an axially compact tensioning wheel, which mainly includes a pulley 1, a connecting cover 2, a swing arm 3, and a planar spiral torsion spring 4. The connecting cover 2 is provided with three mounting feet for installation.

[0024] One end of the swing arm 3 is provided with a mounting hole 5, and the other end is provided with an annular shaft hole 6. The other end face of the pulley 1 away from the connecting cover 2 is machined into a flat shape to facilitate fitting with the engine block or other mounting base, reduce installation interference, and ensure stable force distribution.

[0025] A bearing 7 is press-fitted into the central hole of the pulley 1, and the pulley 1 is mounted on the mounting hole 5 by bolts 8. To reduce friction and wear, the bolts 8 pass through the inner ring of the bearing 7 and are then screwed to the rocker arm 3 for fixation.

[0026] A rotating shaft 9 is provided on the connecting cover 2. The end of the rotating shaft 9 passes through the annular shaft hole 6 of the swing arm 3 and is screwed to an end cover 10. A damping ring 11 is also provided between the end cover 10 and the swing arm 3. The damping ring 11 has a raised edge, which fits tightly with the groove on the peripheral wall of the swing arm to provide rotational damping and prevent the tensioning wheel from vibrating at high frequency under belt vibration. A planar spiral torsion spring 4 is provided between the outer wall of the annular shaft hole 6 and the inner wall of the connecting cover 2. One end of the torsion spring is fixed to the swing arm 3, and the other end is fixed to the connecting cover 2 to provide a constant tension torque.

[0027] The improvement of this utility model lies in the fact that the connecting cover 2 and the pulley 1 are arranged on the same side, and the outward-facing end face of the connecting cover 2 and the outward-facing end face of the pulley 1 are flush or nearly flush. This layout eliminates the height difference between the connecting cover and the pulley in the traditional structure, making the overall structure flatter in the axial direction.

[0028] To prevent the torsion spring from rusting, a friction-reducing ring 12 is fitted onto the annular shaft hole 6 of the swing arm 3. This ring is preferably made of wear-resistant plastic or copper alloy to reduce rotational friction. The open end of the connecting cover 2 contacts the friction-reducing ring 12, thus forming a closed end-face seal that encloses the planar spiral torsion spring 4 inside, preventing dust or liquid corrosion.

[0029] Furthermore, a bearing dustproof mechanism 13 is provided between the pulley 1 and the swing arm 3. This mechanism includes an annular groove 14 and a dustproof ring 15 disposed on the swing arm 3. The edge of the annular groove 14 has a first protruding ring 16 protruding towards the bearing 7, and the annular groove 14 covers one end face of the bearing 7. The first protruding ring 16 is close to the end face of the central shaft hole of the pulley 1, forming a first gap seal. The dustproof ring 15 is sleeved on the bolt 8, covering the other end face of the bearing 7, and the edge of the dustproof ring 15 has a second protruding ring 17 protruding towards the bearing 7. The second protruding ring 17 is close to the end face of the central shaft hole of the pulley 1, forming a second gap seal. This structure of double protruding rings cooperating with the pulley end face constitutes a labyrinthine dustproof path.

[0030] Furthermore, the central shaft hole of the pulley 1 is provided with an annular groove 18, and the outer ring of the bearing 7 is tightly disposed within the annular groove 18. In terms of manufacturing process, the bearing 7 and the pulley 1 can be integrally formed by injection molding, which not only improves the assembly accuracy but also further enhances the connection strength and sealing performance between the bearing 7 and the pulley 1.

[0031] Through the above structural optimization, this tensioner achieves a high degree of axial compactness and excellent protective performance while ensuring functionality, fully meeting the high standards required by modern automotive engines.

Claims

1. An axially compact tensioning wheel, comprising a pulley (1), a connecting cover (2), a swing arm (3), and a planar spiral torsion spring (4); one end of the swing arm (3) is provided with a mounting hole (5), and the other end is provided with an annular shaft hole (6); a bearing (7) is provided in the central hole of the pulley (1), and the pulley (1) is mounted on the mounting hole (5) by bolts (8); a rotating shaft (9) is provided on the connecting cover (2), the end of the rotating shaft (9) passes through the annular shaft hole (6) of the swing arm (3) and is screwed with an end cap (10), a damping ring (11) is also provided between the end cap (10) and the swing arm (3), and a planar spiral torsion spring (4) is provided between the outer wall of the annular shaft hole (6) and the inner wall of the connecting cover (2), characterized in that, The connecting cover (2) and the pulley (1) are arranged on the same side. The outward end face of the connecting cover (2) and the outward end face of the pulley (1) are level or nearly level. The other end face of the swing arm (3) away from the connecting cover (2) and the pulley (1) is flat. A friction-reducing ring (12) is sleeved on the annular shaft hole (6) of the swing arm (3). The open end of the connecting cover (2) contacts the friction-reducing ring (12), thereby achieving the closure of the planar spiral torsion spring (4). A bearing dustproof mechanism (13) is also provided between the pulley (1) and the swing arm (3).

2. The axially compacted tensioner pulley of claim 1, wherein, The bearing dustproof mechanism (13) includes an annular groove (14) and a dustproof ring (15) provided on the swing arm (3). The edge of the annular groove (14) protrudes towards the bearing (7) with a first protruding ring (16). The annular groove (14) covers one end face of the bearing (7). The first protruding ring (16) is close to the end face of the central shaft hole of the pulley (1). The dustproof ring (15) is sleeved on the bolt (8) and covers the other end face of the bearing (7). The edge of the dustproof ring (15) protrudes towards the bearing (7) with a second protruding ring (17). The second protruding ring (17) is close to the end face of the central shaft hole of the pulley (1).

3. The axially compacted tensioner pulley of claim 1, wherein, The central shaft hole of the pulley (1) is provided with an annular groove (18), and the outer ring of the bearing (7) is tightly disposed in the annular groove (18). This structure is mainly completed by injection molding of the bearing (7) and the pulley (1) as a single unit.

4. The axially compact tensioner pulley of claim 1, wherein, The wear-resistant ring (12) is made of wear-resistant plastic or copper alloy.

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