Improved filtering pulley

Abstract

A filter pulley (1) comprising: a hub (2) adapted to be fixed to a shaft rotating about an axis (A); a crown (3) coaxially and freely rotatably mounted on the hub (2); and a filter unit (5) operably arranged between the hub (2) and the crown (3), the hub (2) comprises a first portion (2 ') and a second portion (2' '), the first portion (2') being radially contained by the crown (3) about the axis (A), the second portion (2 '') being only partially contained by the crown (3) about the axis (A), the filter unit (5) being operably disposed between the hub (2) and the crown (3), surrounding the first portion (2 ') of the hub (2) and axially facing the crown (3).

Description

[0001] Cross - reference to related applications

[0002] This patent application claims the priority of Italian Patent Application No. 102022000026352, filed on December 21, 2022, the entire disclosure of which is incorporated herein by reference. Technical field

[0003] The present invention relates to a filtering pulley.

[0004] The present invention is preferably applied to vehicle engine systems, but the application is not exclusive. The application will be mentioned by way of example hereinafter. Background art

[0005] In order to reduce vehicle pollution and comply with national regulations regarding vehicle emission standards, the use of electric motors in combination with or in place of internal combustion engines is increasing.

[0006] In a configuration known in the art as "P0", an electric motor is connected to the crankshaft of an internal combustion engine and operates in a so - called Belt Starting Generator (BSG) mode.

[0007] In such a system, it is useful to use a filtering pulley between the electric motor and the accessory drive belt to drive the alternator.

[0008] In known configurations, the pulley includes a hub, an annular crown, and a filtering unit. The hub is adapted to be connected to the rotor of the alternator; the annular crown is provided with a profile adapted to cooperate with the belt, and the filtering unit is arranged between the hub and the pulley crown to prevent the belt from being dynamically overloaded when torsional vibrations occur on the drive shaft or when the engine speed changes rapidly.

[0009] The filtering unit typically includes springs, such as helical springs or disc springs, or multiple springs or other elastic elements circumferentially arranged between the hub and the crown.

[0010] However, this configuration limits the torque that can be transmitted between the hub and the crown, which can reach 50 Nm to 75 Nm in some configurations.

[0011] Therefore, there is a need to provide a filtering pulley for electric motors installed in different vehicle configurations to allow torque transmission over a wide range of operating conditions.

[0012] The object of the present invention is to meet the above requirements in an optimized and cost - effective manner. Summary of the invention

[0013] The above object is achieved by the filtering pulley described in the appended claims. Brief description of the drawings

[0014] To better understand the present invention, preferred embodiments will be described below by way of non - limiting examples and with reference to the accompanying drawings, in which:

[0015] Figure 1 is a perspective view of a pulley according to the present invention;

[0016] Figure 2 is Figure 1 an exploded perspective view of the pulley in [ ] along its longitudinal axis;

[0017] Figure 3 is along [ ] Figure 1 a sectional view taken along line III - III in [ ]; and

[0018] Figure 4 is along [ ] Figure 3 a sectional view taken along line IV - IV in [ ]. Detailed Description of the Invention

[0019] Referring to the accompanying drawings, a pulley 1 is shown, which mainly consists of the following: a hub 2 (preferably tubular); a crown 3 (preferably tubular), the outside of the crown 3 being coaxial with the hub 2 and rotatably supported on the hub 2 by a support means 4; and a filtering unit 5, the filtering unit 5 being operably arranged between the hub 2 and the crown 3 for torque transmission.

[0020] The hub 2 and the crown 3 are coaxial about a longitudinal axis A, which coincides with the axis of the operating shaft of a motor (not shown).

[0021] Specifically, the hub 2 includes a cylindrical, advantageously tubular, portion 2a, and an inner portion 2a defines a coupling portion 2b for coupling to the aforementioned operating shaft.

[0022] The crown 3 mainly includes a hollow cylindrical portion 3a, sized to radially receive the hub 2 therein. The crown 3 has a profile 3b on the side opposite to the hub 2, and the profile 3b has a plurality of grooves adapted to cooperate with a belt (such as a multi - wedge belt).

[0023] Specifically, the aforementioned support means 4 includes a rolling bearing (such as a ball bearing), radially arranged between the crown 3 and the hub 2.

[0024] Specifically, the hub 2 is divided by a radial flange 6 into a first end 2' and a second end 2” separated from each other, the radial flange 6 extending radially from the hub 2 towards the crown 3 and configured to serve as a shoulder for the aforementioned rolling bearing. Correspondingly, the crown 3 also defines a shoulder radially coinciding with the radial flange 6, which is designed to serve as a shoulder for the aforementioned rolling bearing.

[0025] It should be noted that some parts in the original text seem to have incomplete or unclear information, such as the blanks in "[ ]" in some descriptions. The translation is made as accurately as possible based on the existing content.Advantageously, the support device 4 is radially placed to coincide with the profile 3b having a plurality of grooves, and more specifically centered on the profile 3b. Advantageously, the rolling bearing is symmetrically placed with respect to the profile 3b, i.e., the centers of the balls coincide with the axis of symmetry of the profile 3b.

[0026] Specifically, the first end 2' is radially surrounded inwardly by the hub 2 along the axis A and faces the motor, while the second end 2'' is only radially partially surrounded by the hub 3 along the axis A and supports the filtering unit 5.

[0027] Thus, the filtering unit 5 is supported axially facing the crown 3 and outside the space between the crown 3 and the hub 2 in the radial direction, which space only houses the support device 4.

[0028] The filtering unit 5 mainly includes: a housing 10, which is integrally carried by one of the hub 2 and the crown 3; an actuator 11, which is integrally carried by the other of the hub 2 and the crown 3; and an elastic device 12, which is operatively arranged between the housing 10 and the actuator 11, as described in detail below.

[0029] For the sake of simplicity, a configuration will be described in which the housing 10 is integral with the crown 3 and the actuator 11 is integral with the hub 2. Obviously, this description is not intended to be restrictive.

[0030] The housing 10 mainly includes a first and a second element 13, 14 which are interconnected to form a space 15 isolated from the external environment. Advantageously, lubricant, such as grease, is contained inside the space 15.

[0031] In the illustrated embodiment, the first and second elements 13, 14 are cup-shaped, i.e., each element includes a respective wall 13a, 14a radial with respect to the axis A and axial walls 13b, 14b extending from the outer radial portions of the respective radial walls 13a, 14a.

[0032] Specifically, the first and second elements 13, 14 are dimensioned such that they are rigidly connected by contact with each other, specifically such that one of the axial walls 13b, 14b is radially received inside the other under pressure, thus maintaining the connection of the first and second elements 13, 14.

[0033] Specifically, the second element 14 is rigidly connected to the crown 3 as described below. On the other hand, the second element 13 defines an opening 16 configured to receive the cover 17. Advantageously, the opening 16 is coaxial with the axis A.

[0034] Specifically, the second element 14 is rigidly connected to the crown 3 by a reversible mechanical connection 20 (e.g., by a threaded element or a rivet 21 or other form-fitting connection).

[0035] Specifically, the crown 3 includes a radial portion 3c extending from the end of the cylindrical portion 3a facing the filter unit towards the hub 2. The radial portion 3c and the axial wall 14a of the second element 14 define corresponding openings configured to receive the reversible mechanical connection 20.

[0036] Finally, the closure element 11 includes two protrusions 18 which are diametrically opposed to each other in the circumferential direction with respect to the axis A and extend axially within the chamber 15 from the axial wall 13a of the first element 13. Two additional protrusions 19 are provided on the wall 14a of the second element 14, preferably arranged to face the protrusions 18. The protrusions 18 and 19 are fixedly carried by the corresponding walls or, alternatively, are integrally formed with the corresponding walls.

[0037] Thus, the protrusions ......

[0038] The elastic means 12 advantageously includes an elastic assembly for each part of the space 15, which is circumferentially freely arranged in the space 15 between the protrusions 18 and 19. Each elastic assembly includes at least one spring, which in this case is a helical arch spring mounted between the aforementioned protrusions 18 and 19.

[0039] In the said embodiment, the spring is freely carried without a circumferential free angle of movement between the protrusions 18, 19 and the spring itself. Obviously, a circumferential free angle can be provided between the spring and the corresponding protrusion, or conversely, the spring can be pre-compressed between the protrusions 18 and 19. Furthermore, each elastic assembly can accommodate more springs, and these springs are placed in series or in parallel with each other and are optionally accommodated in a spring support.

[0040] The actuator 11 cooperates with the elastic means 12 and mainly includes a hub portion 11a rigidly carried by the hub 2, and a plurality of spokes 11b radially extending from the hub portion 11a and cooperating in contact with the elastic means 12.

[0041] Advantageously, the hub portion 11a is carried by the hub 2 by contact coupling, particularly it is pressed against the hub ......

[0042] Specifically, the spokes 11b are connected to the hub 11a by a reversible mechanical connection 30 (e.g., by a threaded element or a rivet 31 or other form-fitting couplings).

[0043] Specifically, the hub portion 11a defines a flange 11c radially extending from the hub portion 11a with respect to the axis A. The flange 11c and the spokes 11b define corresponding openings configured to receive the reversible mechanical connection 30.

[0044] Advantageously, the openings that accommodate the reversible mechanical connection 30 between the spoke 11b and the hub portion 11a and the opening that accommodates the mechanical connection 20 between the second element 14 and the crown 3 are coaxial with each other along an axis parallel to the axis A. More preferably, they are substantially coaxial with the support device 4, in particular with the center of the balls of the rolling bearing described herein, that is, they have the same radial distance relative to the axis A.

[0045] Specifically, the flange 11c and the radial wall 3c are thus parallel to each other and spaced apart along the axis A. Specifically, the spoke 11b is axially placed between the radial wall 3c and the flange 11c.

[0046] As described above, when the spoke 11b is axially located between the protrusions 18, 19, the spoke 11b is in contact and cooperation with the elastic device 12 and is free to circumferentially move around the axis A, and the self-end of the spoke 11b cooperates with the elastic component of the elastic device.

[0047] As Figure 4 shown, in the said embodiment, there is an angular gap α between each spoke 11b and the elastic device 12. Obviously, this angular gap α can have different amplitudes or not exist. If there is the above-mentioned gap between the elastic device 12 and the protrusions 18, 19, the above-mentioned angular gap α will be increased.

[0048] The filter unit 5 further includes a damping device 25, which is configured to provide damping between the hub 2 and the crown 3 when the hub 2 and the crown 3 move relative to each other. Advantageously, the damping device 25 is accommodated in the space 15 so as to be isolated from the external environment.

[0049] Specifically, the damping device 25 includes an elastic element 26 operatively arranged between the hub portion 11a of the actuator 11 and the radial wall 13a of the first element 13. Advantageously, the elastic element 26 is a cup spring or a Belleville washer.

[0050] The damping device 25 advantageously includes a pair of rings 27, 28, which are configured to support the elastic element 26 therebetween. In detail, the first ring 27 is assembled on the hub 2 and is in axial contact with the hub portion 11b of the actuator 11, while the second ring 28 is carried to be in axial contact with the radial wall 13a of the first element 13, near the opening 16.

[0051] Advantageously, at least the second ring 28 is configured as a dust-proof ring. Therefore, the damping device 25 also plays a role in isolating the space 15.

[0052] In addition to the above, it is worth noting that the average diameter R' of the multi-wedge portion 3b of the crown 3 is smaller than the average actuation diameter R'' of the spoke 11b, and the average actuation diameter R'' of the spoke 11b is smaller than the maximum diameter R''' of the housing 10.

[0053] Specifically, the average diameter R' refers to the average height of the contour of the multi-wedge portion 3b, and the average actuation diameter R" refers to the midpoint in the radial direction of the portion where the spoke 11b of the actuator 11 and the elastic means 12 are in contact with each other. Obviously, the maximum diameter R" of the housing 10 is the maximum radial extension of the housing.

[0054] The operation of the filtering pulley according to the above-described embodiment of the present invention is as follows.

[0055] In the first operating phase, namely the so-called "boost drive mode", at this time the motor operates as an electric motor, and the speed of the hub 2 tends to exceed the speed of the crown 3. Therefore, the spoke 11b of the actuator 11 transfers torque to the protrusions 18, 19 with the intervention of the elastic means 12.

[0056] The same situation also occurs under the condition of the "generator or recovery mode", that is, when the speed of the crown 3 tends to exceed the speed of the hub 2, at this time torque is supplied to the motor operating as a generator.

[0057] It can be clearly seen from the above the advantages of the filtering pulley according to the present invention.

[0058] Since the filtering unit 5 can be externally connected between the hub 2 and the crown 3, different filtering units 5 of different sizes optimized for the required filtering capacity can be provided without modifying the hub 2 and the crown 3.

[0059] Specifically, the filtering unit 5 is defined within a housing made of a cup-shaped element that is easy to manufacture, and this housing can be connected to the crown 3 / hub 2 by an equally economical mechanism. Therefore, both the manufacture and installation of the filtering unit 5 are economical.

[0060] In addition, the size of the housing 10 and the size of the elastic means can vary according to the required transmissible torque, and since they can radially expand beyond the crown 3, the elastic means 12 can provide sufficient torque transmission capacity and associated filtering performance.

[0061] As can be seen from the above, the axial dimension of the known pulley can be significantly reduced because there is no need to radially arrange a filtering unit between the hub and the crown as is well known in the art.

[0062] Using a reversible mechanical connection (such as a threaded element or a rivet or other form-fitting coupling) between the housing 10 and the crown 30 or between the elements of the actuator 11 allows for easy assembly and disassembly in the case of inspection and maintenance.

[0063] The use of the damping system 25 provides a damping torque that improves the filtering capacity and can be easily adjusted according to the type of elastic element used.

[0064] The specific relative arrangement of reversible mechanical elements (such as threaded elements or rivets) between the housing 10 and the crown 30, or between the elements of the actuator 11, also increases the system strength by reducing the tipping moment. The positioning of the support means 4 also supports this advantage.

[0065] In addition, accommodating the damping device 25 within the space 15 prevents contamination and exposure to substances that could have an adverse effect on the service life of the damping device, thus increasing the service life of the damping device.

[0066] Finally, it is obvious that the filter pulley according to the invention can be modified and varied without departing from the scope of protection defined by the claims.

[0067] For example, the support means can be replaced by a sleeve, or the housing can be made in a different way or in a different shape.

[0068] As mentioned above, the elastic element can include different types and different numbers of springs. Similarly, the damping devices or mechanical connections described herein can also be of different types.

Claims

1. A filtering pulley (1), comprising: A hub (2), said hub (2) being adapted to be fixed to a shaft rotating about an axis (A); A crown (3), said crown (3) being coaxially and rotatably mounted on said hub (2); and a filtering unit (5), said filtering unit (5) being operatively arranged between said hub (2) and said crown (3); said hub (2) comprising a first part (2') and a second part (2''), said first part (2') being radially encompassed by said crown (3) about said axis (A); said second part (2'') being only partially radially encompassed by said crown (3) about said axis (A); said filtering unit (5) being operatively arranged between said hub (2) and said crown (3), around said second part (2'') of said hub (2) and axially facing said crown (3); wherein said filtering unit (5) comprises a housing (10) and an actuator (11), said housing (10) being integrally rotatably connected to one of said hub (2) and said crown (3), said actuator (11) being integrally rotatably connected to the other of said hub (2) and said crown (3), said housing (10) defining a space (15) to accommodate an elastic means (12) operatively arranged between said actuator (11) and said crown (3); wherein said housing (10) comprises a first element (13) and a second element (14), said first element (13) and said second element (14) being connected to each other to define said space (15) and being connected to said one of said hub (2) and said crown (3), said first element (13) and said second element (14) carrying respective stop elements (18, 19), said stop elements extending into said space (15) and dividing said space into a plurality of parts, wherein each part accommodates said elastic means (12), said elastic means (12) being operatively in contact with and arranged between said actuator (11) and said stop elements (18, 19); wherein one of said first element (13) and said second element (14) is connected to said one of said hub (2) and said crown (3) by a mechanical connection (20), said mechanical connection (20, 30) comprising a threaded connection, a rivet connection or a form connection.

2. The pulley according to claim 1, wherein Said elastic means (12) comprises at least one helical spring.

3. The pulley according to claim 1 or 2, wherein, Said elastic means (12) is placed between said hub (2) and said crown (3) with an angular clearance (α) to freely slide between said actuator (11) and said housing (10), or to be in contact between said actuator (11) and said housing (10).

4. The pulley according to any one of claims 1 to 3, wherein, Said elastic means (12) is placed between said stop elements (18, 19) with an angular clearance to freely slide relative to each other or to be in contact with each other.

5. The pulley according to any one of claims 1 to 4, wherein, The actuator (11) includes a hub portion (11a) carried by the second end (2”) of the hub (2) and a plurality of spokes (11b) configured to be in contact engagement with the elastic means (12), the plurality of spokes (11b) being connected to the hub portion (11a) by a mechanical connection (30).

6. The pulley according to any one of claims 1 to 5, wherein, One of the first element (13) and the second element (14) is placed radially inside the other one.

7. A pulley according to any one of claims 1 to 6, comprising damping means (25) located within the space (15) and operatively provided between the housing (10) and the other of the hub (2) and the crown (3), the damping means (25) being configured to provide damping between the housing (10) and the other of the hub (2) and the crown (3) according to the relative rotation of the other of the hub (2) and the crown (3).

8. The pulley according to claim 7, wherein, The damping means (25) includes an elastic element (26) and a pair of rings (27, 28) connected to the elastic element, the pair of rings (27, 28) being in contact engagement with the housing (10) and the other of the hub (2) and the crown (3) respectively.

9. The pulley according to claim 8, wherein, At least one of the rings (27, 28) is a dust lip.

10. The pulley according to any one of claims 1 to 9, wherein, The housing (10) defines an opening (16) configured to receive a cover (17).

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