Spherical joint assembly of crank and connecting rod of windscreen wiper module

Abstract

A ball joint assembly (34, 36, 38) of a crank (30, 32) and a connecting rod (26, 28) of a windshield wiper module is disclosed, the ball joint assembly comprising a crank pin (40) secured to the crank (30, 32) and a ball joint housing comprising a socket (42) arranged to receive the crank pin (40), the socket (42) being secured in an opening (46) at an end of the connecting rod (26, 28), where the socket (42) is configured to receive the crank pin (40), the socket (42) is made in two subsections (48, 50) assembled with each other, with a first subsection (48) overmolded on an opening (46) in an end of the connecting rod (26, 28) and a second subsection (50) fitted on the crank pin (40), the first subsection (48) having a bore (49) configured to receive the second subsection (50).

Description

[0001] The present invention relates to the field of windscreen wiper modules and more particularly to ball joint assemblies between components of such modules.

[0002] The windshield wiper module comprises a wiper drive unit, the shaft of which is connected to two linkage subsystems, which are respectively connected to a wiper shaft rotatably supported in a support member. The support member and the support member of the wiper drive unit are fixed to the vehicle frame.

[0003] The linkage subsystem extends between the wiper drive unit and the wiper shaft and includes a connecting rod coupled to a first crank secured to the wiper drive unit shaft and a second crank secured to the wiper shaft, with at least one of the connections between the connecting rod and the cranks being a ball joint assembly. The linkage subsystem converts the rotational motion of the wiper drive unit shaft into synchronized oscillatory motion of the wiper shaft.

[0004] Some of these modules arrive pre-assembled on the vehicle production line in one piece, with reinforcing ribs between the support members for the drive unit and each of the support members for the wiper shaft. The vehicle frame is attached only to the support members for the wiper drive unit and the wiper shaft. At least one ball joint assembly is manufactured in a dedicated workshop using a suitable press that presses the crankshaft's crank pin into the connecting rod's retainer.

[0005] But nowadays simplified systems have been designed without stiffening ribs between the axles, and while allowing greater flexibility in the position of the axles relative to each other, these systems can be installed on the vehicle, but also means that the ball joint assembly must be realized on site without the use of a stamping press.

[0006] It is therefore sought to design ball joint assemblies that allow assembly directly on the vehicle production line, reducing the workload and, in particular, minimizing the need for hand tools or power tools.

[0007] According to a first aspect, the invention therefore relates to a ball joint assembly of a crank and a connecting rod of a windscreen wiper module, the ball joint assembly comprising a crank pin fixed to the crank and a ball joint housing comprising a socket configured to receive the crank pin, the socket being fixed in an opening provided at the end of the connecting rod, wherein the socket is made in two parts assembled to one another, wherein a first part is overmolded onto the opening in the end of the connecting rod and a second part is fitted onto the crank pin, the first part having a hole configured to receive the second part.

[0008] Providing the socket in two separate sections enables operators on a vehicle assembly line to manufacture the ball joint assembly effortlessly and, in certain advantageous embodiments, by hand (i.e., without the need for hand tools, power tools, or otherwise), while avoiding the risk of a less-than-elastic joint between the socket and the crankpin. Here, the second section of the socket can be assembled using a suitable press, which avoids damaging the section of the socket that surrounds the spherical portion of the crankpin or otherwise deforming the cylindrical form of that section. Furthermore, overmolding the first section onto the connecting rod allows all contact during the assembly process to occur between the two plastic sections (i.e., the two sections of the socket), rather than between the plastic socket that fits to the crankpin and the metal edge that defines the opening of the connecting rod. Consequently, forces generated at the connection between the connecting rod and the crank are more efficiently transferred without the risk of damaging the plastic socket.

[0009] According to an aspect of the invention, the first section has a generally cylindrical form extending along the axis of revolution.

[0010] According to an aspect of the present invention, the first section covers the entire circumference of the opening of the end portion of the connecting rod.

[0011] According to one aspect of the invention, the first section includes a top portion and a bottom portion disposed on opposite sides of the end of the connecting rod, both of which have diameters greater than a diameter of the opening of the end of the connecting rod.

[0012] According to an aspect of the invention, the first section has a first radial dimension in a first direction parallel to the elongated axis of the connecting rod and a second radial dimension in a second direction perpendicular to the first direction, the first radial dimension being larger than the second radial dimension.

[0013] According to an aspect of the invention, the second section has a base portion adjacent the crank, the base portion being in the form of a continuous annular band.

[0014] According to an aspect of the invention, the first section and the second section are fastened by a snap-fit arrangement.

[0015] According to one aspect of the present invention, a top end portion of the second section forms a slope configured to facilitate insertion into the first section.

[0016] According to one aspect of the invention, the second section includes a plurality of resilient fingers forming a first lateral protrusion and a shoulder forming a second lateral protrusion.

[0017] According to an aspect of the present invention, the first subsection and the second subsection are made of different materials.

[0018] According to an aspect of the invention, the second subsection is made of a material having a lower coefficient of friction than the material of the first subsection.

[0019] According to a second aspect, the invention relates to a vehicle comprising a windscreen wiper module having a ball joint assembly as described above.

[0020] According to a third aspect, the present invention relates to an assembly process for a windscreen wiper module comprising a ball joint assembly as described above, the assembly process comprising at least:

[0021] - a step of overmolding a first portion of a socket on the end of the connecting rod of the windscreen wiper module,

[0022] - a step of fitting the second subsection of the socket onto the crank pin of the crank of the windscreen wiper module,

[0023] - A step of joining the connecting rod and the crank by snapping the two parts of the socket together.

[0024] This process enables each of these steps to be performed in different locations using different tools. The overmolding step can be performed separately with connecting rods in an easily accessible mold. The assembly step can be performed in a dedicated workshop using a press that generates greater forces than an operator can generate manually. Finally, the assembly step of the two different parts of the socket can be performed by an operator directly on the vehicle assembly line without requiring excessive effort or the use of tools.

[0025] Other characteristics and advantages of the invention will become apparent from the following description of several examples of embodiment given by way of indication and not by way of limitation with reference to the accompanying schematic drawings, in which:

[0026] Figure 1 A windshield wiper module embodying a ball joint assembly according to the present invention is shown;

[0027] Figure 2 yes Figure 1 Detailed view of the module showing the end of the connecting rod and the end of the crank connected by the ball joint assembly according to the present invention;

[0028] Figure 3 yes Figure 2 a cross-sectional view of the parts visible in the figure;

[0029] Figure 4 yes Figure 2 a view of the components prior to their assembly, the view being intended to make visible the split socket, one portion being overmolded onto the end of the connecting rod and one portion being mounted on the crank;

[0030] Figure 5 is an exploded view of the components of the crank (i.e., the crank pin and the portion of the socket that is mounted on the crank); and

[0031] Figure 6 FIG. 2 is a cross-sectional view of another position of the ball joint assembly according to the present invention.

[0032] Figure 1 A linkage system for actuating windscreen wipers of a motor vehicle is shown, hereinafter referred to as system 2. When installed in a motor vehicle, the system 2 is typically fixed to the frame of the vehicle by means of brackets schematically illustrated here.

[0033] The first support 4 supports a schematically illustrated electric gear motor 6 , the output shaft 8 of which is intended to drive a first linkage subsystem 10 for a first windscreen wiper 12 and a second linkage subsystem 14 for a second windscreen wiper 16 , each comprising a wiper arm for actuating the wiper blades.

[0034] The longitudinal ends of the wiper arms are fastened to drive shafts 18, 20 which are held adjacent the windshield by brackets 22, 24, and the opposite longitudinal ends of the wiper arms are connected to the wiper blades.

[0035] Each linkage subsystem 10, 14 extends from the output shaft 8 of the motor 6 to one of the drive shafts 18, 20 and includes a connecting rod 26, 28 and a crank 30, 32. As illustrated, the first linkage subsystem 10 includes a first connecting rod 26 and a first crank 30, and the second linkage subsystem 14 includes a first connecting rod 28 and a second crank 32.

[0036] The connecting rods 26, 28 have a substantially rectilinear elongated overall shape extending between a first longitudinal end 26a, 28a and a second longitudinal end 26b, 28b along an elongation axis A. The connecting rods are made, for example, by stamping or forging and have a convex central portion and planar longitudinal ends.

[0037] The first longitudinal ends 26a, 28a of the connecting rods 26, 28 of the linkage subsystems 10, 14 are hinged to the output shaft 8 of the electric gear motor 6 through a first ball joint assembly 34, and the second longitudinal ends 26b, 28b are hinged to the first ends of the cranks 30, 32 of the linkage subsystems through second ball joint assemblies 36, 38.

[0038] The second ends of the cranks 30 , 32 are rotationally integrally connected to the drive shaft of the corresponding windscreen wiper.

[0039] Each ball joint assembly 34, 36, 38 is made up of a ball joint housing including a fixing device to the connecting rod and a crank pin fixed to the crank. The crank pin is shaped to be at least partially received in an internal cavity of the ball joint housing, which has a corresponding form and size.

[0040] More particularly, the crank pin has a spherical portion having dimensions (ie, diameter) equal to corresponding dimensions of the interior cavity of the ball joint housing.

[0041] As previously mentioned, the present invention relates to a ball joint assembly in which the ball joint housing is a socket made of two parts assembled to one another, a first part being fixed to the end of the connecting rod (in particular by overmolding) and a second part being fixed to the crank pin. This split socket configuration is advantageous in situations where an operator must manually secure the connection between the connecting rod and the crank.

[0042] like Figure 2 As shown, the present invention will be described more particularly with reference to a specific form of a ball joint assembly arranged between the first connecting rod and the first crank of the first linkage subsystem, but it should be noted that the present invention can be implemented in a similar manner at each ball joint assembly of the system 2.

[0043] Figure 2 The ball joint assembly is shown comprising a crank pin 40 fixed to a first end of the crank 30 and a socket 42 forming the aforementioned ball joint housing, one portion of which is fixed to the second end 26b of the connecting rod 26. The ball joint assembly allows rotational movement of the crank pin relative to the socket about three axes.

[0044] The socket is made of plastic, while both the crank pin 40 and the end of the connecting rod 26 are metal.

[0045] Figure 3 The cooperating segmented form of the crank pin and socket is shown in cross-section, and the inventive feature of the socket being made in two segments is shown.

[0046] The crank pin 40 has a spherical portion 44 and the socket 42 is configured to both receive the spherical portion of the crank pin 40 and to be secured to the connecting rod in an opening 46 at the end of such connecting rod.

[0047] As mentioned above, the socket 42 is made in two parts. The first part 48 (also called the receiving part) is fixed to the connecting rod 26, and the second part 50 (also called the housing part) is received in the receiving part of the socket 42 and is arranged to surround the spherical portion 44 of the crank pin 40.

[0048] The connection between the connecting rod 26 and the crank 30 is achieved by snap-fitting the first section 48 and the second section 50 of the assembly socket 42. Figure 4 and Figure 5 As can be seen more clearly in FIG, the second section 50 has snap-fit means 52 (here resilient fingers) which create an abutment when the second section 50 is secured to the first section 48. Of course, it will be appreciated that in other embodiments the snap-fit means may alternatively be carried by the first section.

[0049] The first subsection 48 of the socket 42 is overmolded onto the end of the connecting rod. The overmolding step is performed in a specific factory or workshop before the vehicle is assembled. On the other hand, the assembly of the connecting rod 26 and the first subsection 48 of the socket 42 to the second subsection 50 of the socket 42 is performed on the vehicle assembly line.

[0050] The first section 48 has a generally cylindrical form extending along an axis of rotation. The first section 48 of the socket 42 extends on either side of the end of the connecting rod 26 according to this axis of rotation, so that the planar surface of this end lies in a recess 54 of the first section of the socket. This recess 54 is located between a top portion 56 of the first section, arranged on one side of the connecting rod, and a bottom portion 58 of the first section, arranged on the other side of the connecting rod, both sections having the same axial thickness. Overmolding results in radial dimensions of the two sections 56, 58 of the first section that are greater than the corresponding dimensions of the opening at the end of the connecting rod. This ensures that the first section 48 of the socket 42 is securely attached to the connecting rod.

[0051] The first subdivision 48 of the socket 42 is provided with a hole 49 forming an internal cavity extending entirely along the axial dimension of the socket and adapted to receive the second subdivision. At the bottom end 480 of the first subdivision 48 of the socket (i.e. at the end of the socket intended to be close to the crank), the size of the hole 49 is enlarged to form what will now be referred to as Figure 3 A counterbore 60 is depicted which is arranged to receive a shoulder of the second subsection of the socket.

[0052] The second subsection 50 of the socket 42 is assembled to the spherical portion of the crank pin. The assembly step around the crank pin is previously performed in a specific factory or workshop, and the set formed by the crank and the second subsection 50 of the socket 42 is subsequently connected to the first subsection 48 of the socket 42 on the assembly line of the vehicle.

[0053] The second portion 50 of the socket comprises snap-fit means 52 arranged at regular intervals around the circumference of the socket. The snap-fit means are constituted by elastic fingers extending axially along the second portion 50 and forming first lateral projections in the radial direction. Taking into account the axial dimension that the first portion has to restore when the two portions are snapped together, the heads of the snap-fit means 52 are located near the top wall 70 of the second portion 50 (i.e. the end of the second portion opposite the cranks 30, 32) and the articulation axis 53 of the elastic fingers is located in the center of the second portion. During the insertion of the second portion 50 into the first portion, the snap-fit means are constrained by the wall that delimits the hole 49 in the first portion.

[0054] The second subdivision 50 of the socket further comprises a shoulder 62 forming a second lateral protrusion at the bottom end of the second subdivision. The axial distance between the snap-fit means 52 and the shoulder 62 is less than the axial dimension of the first subdivision 48 and is equal to the axial dimension between the counterbore 60 and a top end 481 of the first subdivision 48, which is opposite to the bottom end 480 of the first subdivision. The dimensions of this counterbore 60 are radially determined to correspond to the radial dimensions of the shoulder. Figure 3 As shown, when the second section 50 is inserted into the first section 48 , the counterbore 60 is a housing for a shoulder 62 that abuts against a top surface of the counterbore.

[0055] In this axial position, the snap-fit means 52 (here a resilient tongue) sufficiently exceeds the top end 481 of the first segment 48 to adopt its original position and form an axial abutment against the top end 481 of the first segment 48, in the opposite direction of the axial abutment formed by the shoulder. The first segment 48 is fixed to the second segment 50 between its two lateral projections.

[0056] The first and second subsections of the socket are preferably made of the same material, more particularly a material with low friction and good wear properties. In particular, engineering plastics such as PTFE, PEEK, POM, polyimide, nylon, and UHMW PE may be preferred for the first and second subsections of the socket. Among possible variations, the first and / or second subsections of the socket may be filled with a filler material to improve their wear properties, such as glass fiber or carbon fiber; or filled / impregnated with a lubricant to reduce friction, such as graphite, molybdenum disulfide, or oil. A skilled person will be able to determine the optimal composition and configuration for any given embodiment of the present invention.

[0057] In certain embodiments, the socket can be made of different materials between the segments. In this context, the second segment 50, which must surround the spherical portion 44 of the crank pin 40, is made of a material having lower friction characteristics than the material used to overmold the first segment 48 and only has to cooperate with the second segment 50.

[0058] It should be noted that the second section interacts here with the first section of the socket, rather than with the opening of the connecting rod. This feature allows for a better distribution of the workload at the junction between the connecting rod and the crank, since the first section, made of plastic, interacts with another section, also made of plastic, so that the second section is not subjected to the shearing effects caused by the longitudinal forces generated by the first section due to the motor drive.

[0059] Figure 4 and Figure 5 Both the first and second subdivisions of the socket are shown during different steps of the assembly process.These figures make other characteristics of the two subdivisions of the socket visible.

[0060] Figure 4 The first subsection 48 of the socket 42 is shown covering the entire perimeter of the opening 46 of the end 26 b of the connecting rod 26 .

[0061] The first section 48 has a first radial dimension in a first direction parallel to the axis of extension of the connecting rod 26, which is greater than a second radial dimension in a second direction perpendicular to the first direction of this first section 48. Longitudinal forces parallel to the longitudinal direction of the connecting rod are applied to the connection between the connecting rod and the crank more than transverse forces, and the difference between these radial dimensions allows these forces to be appropriately handled.

[0062] Furthermore, the first section 48 has an opening with a circular cross section, rather than an oval cross section like the opening of the connecting rod. Thus, the interaction with the second section 50 having a circular outer diameter is optimized and the forces are better distributed.

[0063] Figure 4 The second subsection 50 of the socket 42 is also clearly shown.

[0064] The second section 50 has a base portion 64 adjacent to the crank, and a top portion 66. The base portion 64 is configured to be surrounded by the first section when the windshield wiper module is secured to the vehicle, and the top portion 66 extends beyond the first section opposite the crank.

[0065] The base portion 64 is a continuous annular band that includes a shoulder 62 at the bottom end of the second section. Only slots 68 that help form a snap-fit arrangement are provided on this continuous annular band. Figure 4 In the illustrated embodiment, shoulder 62 is interrupted by a cutout 69 .

[0066] The top portion 66 is here closed by a top wall 70 to prevent the penetration of dirt, water and dust. The top portion 66 has a wall 72 between the base portion and the top wall, which is inclined relative to the annular band of the base portion to form a ramp, thereby facilitating the insertion of this top portion 66 and then the base portion 64 into the first subsection. The snap-fit means are arranged in relief, protruding from the inclined wall of the top portion 66.

[0067] Thus, due to the inclined surface formed in the top portion of the second segment, the second segment of the socket can be inserted into the first segment without difficulty, thereby allowing the step of assembling the two segments of the socket to be easily performed by an operator on a vehicle assembly line. The snap-fit means retracts into the second segment due to the slot formed in the base portion, allowing the second segment to be inserted into the first segment. The operator knows when to stop insertion because shoulder 62 meets counterbore 60. In this position, the snap-fit means disengage, and they elastically return to their original shape to ensure axial locking in the other direction.

[0068] Figure 5 Another assembly step is shown, which is carried out at another location, in a specific workshop, rather than on the vehicle assembly line. The second part of the socket must be assembled on the crank pin, and this second part can be assembled on the crank pin using a suitable press, so that there is no need to plan a large cutout in the annular band to increase its elasticity.

[0069] According to the above description, the connection between the connecting rod and the crank of the first linkage system or the second linkage system can be implemented by such a socket made in two parts. The present invention can also be implemented at the connection between the connecting rod and the motor output shaft 8. Figure 6 Such an embodiment is shown.

[0070] The output shaft (not shown here) is fixed to the operating lever 74 by means of a specific crank pin 40 having two spherical parts 44, a first spherical part 441 immediately adjacent to the operating lever 74 and a second spherical part 442. The connection between the linkage subsystem and the second spherical part 442 is identical to the connection described previously, the socket being formed in two parts 48, 50, and the second part 50 having a top wall 70, thereby preventing dirt, water and dust from entering the second part.

[0071] It will be appreciated that the connection between the other linkage subsystem and the first spherical portion can be identical to the split socket connection described above, with the exception of the arrangement of the top wall of the second segment, which will be located between the two spherical portions and will require an opening in the top wall to allow the crank pin to pass through it.

[0072] As just described, the present invention achieves its intended purpose by providing a ball joint assembly that effectively transmits force at the joint between the connecting rod and the crank and is easy for an operator to assemble on an assembly line. Of course, the present invention is not limited to the examples just described, and many modifications may be made to these examples without departing from the scope of the present invention.

Claims

1. A ball joint assembly (34, 36, 38) of a crank (30, 32) and a connecting rod (26, 28) of a windshield wiper module, the ball joint assembly comprising a crank pin (40) fixed to the crank (30, 32) and a ball joint housing, the ball joint housing comprising a socket (42) configured to receive the crank pin (40), the socket (42) being fixed in an opening (46) provided at an end of the connecting rod (26, 28), wherein The socket (42) is made in two sections (48, 50) assembled to each other, wherein a first section (48) is overmolded at an opening (46) at the end of the connecting rod (26, 28) and a second section (50) is fitted on the crank pin (40), the first section (48) having a hole (49) configured to receive the second section (50).

2. The ball joint assembly (34, 36, 38) of claim 1, wherein: The first section (48) has a generally cylindrical form extending along the axis of revolution.

3. A ball joint assembly (34, 36, 38) as claimed in any one of the preceding claims, wherein: The first section (48) covers the entire periphery of the opening (46) at the end of the connecting rod (26, 28).

4. A ball joint assembly (34, 36, 38) as claimed in any one of the preceding claims, wherein: The first section (48) includes a top portion (56) and a bottom portion (58), the top portion and the bottom portion (56, 58) being arranged on opposite sides of the end of the connecting rod, and the diameters of the top portion and the bottom portion (56, 58) are both larger than the corresponding diameters of the opening (46) at the end of the connecting rod (26, 28).

5. A ball joint assembly (34, 36, 38) as claimed in any one of the preceding claims, wherein: The first section (48) has a first radial dimension in a first direction parallel to the elongated axis of the connecting rod (26, 28) and a second radial dimension in a second direction perpendicular to the first direction, the first radial dimension being greater than the second radial dimension.

6. A ball joint assembly (34, 36, 38) as claimed in any one of the preceding claims, wherein: The second section (50) has a base portion (64) adjacent the cranks (30, 32), the base portion being in the form of a continuous annular band.

7. A ball joint assembly (34, 36, 38) as claimed in any one of the preceding claims, wherein: The first section (48) and the second section (50) are secured by a snap-fit arrangement (52).

8. A ball joint assembly (34, 36, 38) as claimed in any one of the preceding claims, wherein: A top portion (66) of the second subsection (50) forms a ramp configured to facilitate insertion into the first subsection (48).

9. A ball joint assembly (34, 36, 38) as claimed in any one of the preceding claims, wherein: The second section (50) includes a plurality of resilient fingers forming a first lateral projection and a shoulder (62) forming a second lateral projection.

10. A ball joint assembly (34, 36, 38) as claimed in any one of the preceding claims, wherein: The first subsection and the second subsection (48, 50) are made of different materials.

11. The ball joint assembly (34, 36, 38) of claim 11, wherein: The second subsection (50) is made of a material having a lower coefficient of friction than the material of the first subsection (48).

12. A vehicle comprising a windscreen wiper module having a ball joint assembly (34, 36, 38) according to any one of the preceding claims.

13. A method for assembling a windscreen wiper module, the windscreen wiper module comprising a ball joint assembly according to any one of claims 1 to 12, the method comprising at least: - a step of overmolding a first portion (48) of a socket (42) on the end of a connecting rod (26, 28) of said windscreen wiper module, - a step of fitting the second portion (50) of the socket (42) onto the crank pin (40) of the crank (30, 32) of the windscreen wiper module, - a step of joining together the connecting rod (26, 28) and the crank (30, 32) by snapping together the two parts (48, 50) of the socket (42).

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