CORE PIN ASSEMBLY FOR MANUFACTURING PIVOT SHAFT HOUSING FOR A VEHICLE WIPER DEVICE, A METHOD FOR MANUFACTURING PIVOT SHAFT HOUSING AND A PIVOT SHAFT HOUSING

Abstract

The present invention relates to a core pin assembly comprising two sliding elements configured for use as a component of a mold assembly for a pivot shaft housing wherein the core pin assembly comprises two sliding elements provided with a plurality of longitudinal projections forming a plurality of longitudinal recesses there between; and a shape of the longitudinal projections of one sliding element corresponds to a shape of the longitudinal recesses of the other sliding element; wherein the two separate sliding elements are configured for engaging in a reversible manner, so that the longitudinal projections of one sliding element are positioned in the longitudinal recesses of the other sliding element. The present invention further relates to a method of manufacturing pivot shaft housing using the core pin assembly. The invention relates also to a pivot shaft housing comprising a hole for supporting a pivot shaft, obtained using this method.

Claims

1. A core pin assembly comprising: two sliding elements configured for use as a component of a mold assembly for a pivot shaft housing, wherein the two sliding elements are provided with a plurality of longitudinal projections forming a plurality of longitudinal recesses there between, wherein a shape of the longitudinal projections of one sliding element corresponds to a shape of the longitudinal recesses of the other sliding element, and wherein the two separate sliding elements are configured for engaging in a reversible manner, so that the longitudinal projections of one sliding element are positioned in the longitudinal recesses of the other sliding element.

2. The core pin assembly according to claim 1, wherein the sliding elements have substantially the same shape.

3. The core pin assembly according to claim 2, wherein the sliding elements are identical.

4. A sliding element for use in a core pin assembly according to claim 1, wherein the sliding element is provided with a plurality of longitudinal projections forming a plurality of longitudinal recesses there between.

5. The sliding element according to claim 4, further comprising at least two recesses and at least two projections.

6. The sliding element according to claim 5, wherein a diameter of the sliding element is different in different cross sections of the sliding element taken in a perpendicular direction to the longitudinal axis of the sliding element, and wherein the diameter of the sliding element increases regularly from one longitudinal end of the sliding element to the other longitudinal end of the sliding element.

7. A mold assembly for forming a pivot shaft housing for a vehicle wiper device, the mold assembly comprising: a mold provided with a cavity for containing a material and a core pin assembly according to claim 1, wherein the core pin assembly is configured to be inserted in the cavity.

8. A method for manufacturing a pivot shaft housing, comprising: providing a mold assembly comprising a mold for containing a material and a core pin assembly according to claim 1; delivering the material into the mold for forming the pivot shaft housing; and removing the core pin assembly from the pivot shaft housing by drawing the sliding elements out from the pivot shaft housing.

9. The method according to claim 8, wherein the material is plastic or metal.

10. A pivot shaft housing for a vehicle wiper device, comprising: a through hole comprising two axially opposite ends, wherein an inner surface of the hole comprises a plurality of spatial structures, said spatial structures being arranged extending slant along at least part of the hole, so that each spatial structure defines a groove at one end and a rib at another end, and wherein the spatial structures are arranged so that at both ends of the hole, each two neighboring spatial structures define the rib and the groove, respectively.

11. The pivot shaft housing according to claim 9, wherein the inner surface of the hole comprises at least four spatial structures, so that at both ends of the hole said spatial structures define at least two grooves and at least two ribs the inner surface of the hole comprises ten spatial structures, so that at both ends of the hole said spatial structures define five grooves and five ribs.

12. The pivot shaft housing according to claim 10, wherein the grooves of the pivot shaft housing are configured to contain a lubricant for improving lubrication properties.

13. The pivot shaft housing according to claim 10, wherein the pivot shaft housing is formed of plastic or the pivot shaft housing is formed of metal.

14. The pivot shaft housing according to claim 10, wherein the housing comprises at least one portion of the hole arranged at at least one end of the hole comprising spatial structures extending parallel along the hole.

15. The pivot shaft housing according to claim 14, wherein the housing comprises at least one portion of the hole arranged at each end of the hole comprising spatial structures extending parallel along the hole.

Description

BRIEF DESCRIPTION OF FIGURES

[0046] The present invention is described in greater details with reference to accompanying figures, in which:

[0047] FIG. 1 is a perspective view of a pivot shaft housing for a vehicle wiper device supporting a pivot shaft therein according to the present invention.

[0048] FIG. 2 is a general view of a wiper module for a vehicle wiper device.

[0049] FIG. 3 is a front view of the pivot shaft housing supporting the pivot shaft therein according to the present invention.

[0050] FIG. 4a-c are cross-section views according to IVa-IVa, IVb-IVb, IVc-IVc of the pivot shaft housing of FIG. 3, supporting the pivot shaft therein.

[0051] FIG. 5 is a schematic longitudinal cross-section partial view of the pivot shaft housing supporting a pivot shaft therein.

[0052] FIG. 6 is a perspective view of an embodiment of pivot shaft housing for a vehicle wiper device according to the present invention.

[0053] FIG. 7 is a partial view of the pivot shaft housing of FIG. 6 presenting a housing part of the pivot shaft housing.

[0054] FIG. 8 is a sectional perspective view of the housing part of FIG. 6.

[0055] FIG. 9 is a front view of the pivot shaft housing of FIG. 6.

[0056] FIG. 10a-c are cross-section views according to Xa-Xa, Xb-Xb, respectively Xc-Xc of the pivot shaft housing of the same embodiment.

[0057] FIG. 11a-c are perspective views of embodiments of core pin assembly, accordingly: disassembled (FIG. 11a), in a semi-assembled state (FIG. 11b) and assembled (FIG. 11c) according to the present invention.

[0058] FIG. 12 is a front view of the core pin assembly according to the present invention.

[0059] FIG. 13a-c are cross-section views according to XIIIa-XIIIa, XIIIb-XIIIb, XIIIc-XIIIc of the core pin assembly of FIG. 12.

[0060] FIG. 14 is a partial view of a mold assembly according to the present invention.

[0061] FIG. 2 shows a general view of a wiper module 1 for a vehicle wiper device. As can be seen in FIG. 2, the wiper module 1 comprises, for example, two pivot shaft housings 6, each supporting pivot shaft 8 therein. Such a structure of the wiper module 1 is commonly used in vehicles like cars, trains or other fast vehicles. The wiper module 1 illustrated is built up of a wiper motor 2 connected with a link assembly 3. The wiper module 1 includes two cranks 4. The link assembly 3 is coupled with the pivot shaft 8 via the crank 4. The wiper motor 2 provides propulsion for the link assembly 3. The link assembly 3 further drives the pivot shaft 8 via the crank 4. Thus, the pivot shaft 8 rotates in the pivot shaft housing 6. The wiper module 1 further comprises a frame tube 5 for supporting the pivot shaft housing 6.

[0062] The pivot shaft housing 6 according to the present invention is presented in FIG. 6. The pivot shaft housing 6 comprises a housing part 7 presented in FIG. 7. The housing part 7 of the pivot shaft housing 6 comprises a through hole 9. The through hole 9 comprises two axially opposite ends 10, 11. Preferably, the housing part 7 of the pivot shaft housing 6 has substantially cylindrical external shape.

[0063] An inner surface of the through hole 9 can be seen in FIG. 8. FIG. 8 is a sectional perspective view of the housing part 7 of the pivot shaft housing 6 of FIG. 6. An inner surface of the through hole 9 comprises a plurality of spatial structures 14. The spatial structures 14 extend slant along at least part of the hole 9. The part of the hole 9 should be understood as a section of a distance between two opposite ends 10, 11 of the hole 9. The spatial structures 14 are arranged at an angle with respect to the longitudinal axis A of the hole 9. Further, the spatial structures 14 are arranged adjacent to each other.

[0064] The inner surface of the hole 9 is substantially formed by surfaces of the spatial structures 14. Surfaces of the slant spatial structures 14 are defined, for example, by a segment of a lateral surface of a truncated cone. The segment has a shape obtained by cutting of a lateral surface of a truncated cone between two slant heights of a truncated cone.

[0065] The surfaces of the spatial structures 14 define, in substantially each cross section taken in a perpendicular direction to the axis A of the hole 9, two diameters. The surfaces of the spatial structures 14 define first diameter D.sub.1 at one end 10 of the hole 9 and first diameter D.sub.1 at the other end 11 of the hole 9. Along the housing 6, first diameters D.sub.1 and D.sub.1 are diameters defined by ribs 13 of the housing 6. Further, the surfaces of the spatial structures 14 define second diameter D.sub.2 at one end 10 of the hole 9 and second diameter D.sub.2 at the other end 11 of the hole 9. Along the housing 6, second diameters D.sub.2 and D.sub.2 are diameters defined by grooves 12 of the housing 6.

[0066] First diameters D.sub.1, D.sub.1 increase from, respectively, one end 10 and the other end 11 of the hole 9 towards, respectively, the other end 11 and one end 10 of the hole 9 until a maximum of first diameter. Meanwhile, second diameters D.sub.2, D.sub.2 decrease from respectively, one end 10 and the other end 11 of the hole 9 towards, respectively, the other end 11 and one end 10 of the hole 9 until a minimum of second diameter.

[0067] It should be noted that there is a cross section in which first and second diameters defined by grooves 12 and ribs 13 of the housing 6 are equal. When going from one end 10 towards said cross section a difference between first and second diameter D.sub.1 and D.sub.2 decreases. Also, when going from the other end 11 towards said cross section a difference between and second diameter D.sub.1 and D.sub.2 decreases. Thus, in said cross section diameter D.sub.1 equals D.sub.2 and diameter D.sub.1 equals D.sub.2. Moreover, in said cross section there is defined a single circle, so that D.sub.1=D.sub.2=D.sub.1=D.sub.2. Preferably, said cross section is a central cross section. The central cross section is positioned, preferably, in the middle between one end 10 and the other end 11 of the hole 9 as illustrated FIG. 5.

[0068] In a preferred embodiment, the hole 9 comprises first substantially cylindrical portion 15 at one end 10 and second substantially cylindrical portion 16 at the other end 11. First substantially cylindrical portion 15 and second substantially cylindrical portion 16 comprise a plurality of spatial structures 14 extending parallel along the hole 9. Thus, a plurality of spatial structures 14 are arranged in parallel with respect to the axis A of the hole 9. It should be noted that first diameters D.sub.1, D.sub.1 and second diameters D.sub.2, D.sub.2 are constant along the whole cylindrical portions 15, 16. Accordingly, diameters D.sub.1 and D.sub.2 are constant along the whole first substantially cylindrical portion 15 and diameters D.sub.1 and D.sub.2 are constant along the whole second substantially cylindrical portion 16.

[0069] Now a reference is made to FIGS. 10a and 10c, which present cross section views of the pivot shaft housing 6 of FIG. 9. FIG. 10a shows a cross section view at one end 10 of the hole 9 of the pivot shaft housing 6. FIG. 10c shows a cross section view at the other end 11 of the hole 9 of the pivot shaft housing 6. In a cross section taken in a perpendicular direction to the axis A of the hole 9 surfaces of the spatial structures 14 define substantially two circles. The first circle has first diameter D.sub.1 and the second circle has second diameter D.sub.2 at one end 10 of the hole 9. The first diameter D.sub.1 is substantially smaller than the second diameter D.sub.2. The above described relationship is the same for diameters D.sub.1 and D.sub.2 at the other end 11 of the hole 9.

[0070] FIG. 10b shows a central cross section in the central part of the hole 9 of the pivot shaft housing 6. In the central cross section there is defined a single circle. The central cross section of the hole 9 is preferably positioned in the middle between one end 10 and the other end 11 of the hole 9.

[0071] Referring again to FIG. 8, each spatial structure 14 defines a groove 12 of the housing 6 at one end 10 and a rib 13 of the housing 6 at the other end 11. The spatial structures 14 are arranged in such a manner that at both ends 10, 11 of the hole 9 each two neighboring spatial structures 14 define the rib 13 of the housing 6 and the groove 12 of the housing 6, respectively.

[0072] The spatial structures 14 forming grooves 12 and ribs 13 can be seen in FIG. 8. Therefore, as an example, one slant spatial structure 14 defines a groove 12 from one end 10 to the central cross section. Further, the one slant spatial structure 14 defines a rib 13 from the central cross section to the other end 11, and conversely. A neighboring and adjacent slant spatial structure 14 defines a rib 13 from one end 10 to the central cross section. Further, the neighboring slant spatial structure 14 defines a groove 12 from the central cross section to the other end 11.

[0073] It should be also understood that first substantially cylindrical portion 15 and second substantially cylindrical portion 16 are provided with grooves 12 and ribs 13 being an extension of grooves 12 and ribs 13 formed by the slant spatial structures 14 between first substantially cylindrical portion 15 and second substantially cylindrical portion 16.

[0074] Surfaces of the parallel spatial structures 14 are defined by a segment of a lateral surface of a cylinder. The segment has a shape obtained by cutting of a lateral surface of a cylinder between two generating lines of a cylinder.

[0075] FIG. 5 presents a schematic cross-section view of the pivot shaft housing 6 supporting the pivot shaft 8 therein taken in a direction of the axis A of the hole 9. It should be understood that internal surface of the hole 9 presented in this cross section view is denoted by a diameters D.sub.1 and D.sub.1, shown in FIGS. 10a and 10c. In other words, FIG. 5 shows a cross section through ribs 13 of the housing 6 only. Thus, it should be noted that said cross section is an aligned section of the pivot shaft housing 6 with the pivot shaft 8.

[0076] As can be seen from FIG. 5, a shape of the through hole 9 is substantially formed by two truncated cones. The two truncated cones are connected with bases having larger diameter. Therefore, preferably in the middle of the longitudinal axis A of the hole 9 there is provided a diameter D.sub.1=D.sub.1 with maximum value. At both ends 10, 11 of the hole 9 there are provided two substantially cylindrical portions 15, 16. As can be seen, the substantially cylindrical portions 15, 16 of the hole 9 act as bearings for the pivot shaft 8. Thus, there is no need to provide any bearing or bush in the pivot shaft housing 6 in order to support a pivot shaft 8 and minimize coaxial shaft play between the hole 9 and the pivot shaft 8.

[0077] The core pin assembly 17 according to the present invention is presented in FIG. 11a-11c. FIG. 11a-c are perspective views of embodiments of the core pin assembly 17, accordingly: disassembled (FIG. 11a), in a semi-assembled state (FIG. 11b) and assembled (FIG. 11c).

[0078] The core pin assembly 17 comprises one sliding element 18 and the other sliding element 18. In the preferred embodiment illustrated, the first sliding element 18 and the second sliding element 18 are identical, therefore single sliding element 18 will be further described. In other embodiments, not illustrated, the sliding elements 18, 18 may have different dimensions, such as different total lengths, different diameters, etc.

[0079] The sliding element 18 has in particular substantially tapered shape.

[0080] The sliding element 18 further comprises a core 23. The sliding element 18 is provided with a plurality of longitudinal projections 20 forming a plurality of longitudinal recesses 19 between the plurality of longitudinal projections 20. A plurality of projections 20 project from the core 23. The sliding element 18 has first end 21 and top end 22. First end 21 and top end 22 are axially opposite to each other.

[0081] In a preferred embodiment, the sliding element 18 further comprises first substantially cylindrical section 25 and second substantially cylindrical section 26 in connection with a tapered section 24. First substantially cylindrical section 25 and second substantially cylindrical section 26 are provided at first end 21 and top end 22, respectively. Thus, the tapered section 24 is positioned between first substantially cylindrical section 25 and second substantially cylindrical section 26.

[0082] An external surface of the sliding element 18 is formed by a plurality of outermost surfaces of the longitudinal projections 20. Each surface of the longitudinal projection 20 in a tapered section 24 of the sliding element 18 is defined by a segment of a lateral surface of a truncated cone. The segment of a lateral surface of a truncated cone has a shape obtained by cutting of a lateral surface of a truncated cone between two slant heights of a truncated cone.

[0083] Surfaces of the longitudinal projections 20 in first substantially cylindrical section 25 and second substantially cylindrical section 26 are defined by segments of a lateral surface of a cylinder. Each segment of a lateral surface of a cylinder has a shape obtained by cutting of a lateral surface of a cylinder between two generating lines of a cylinder.

[0084] It should be understood that first substantially cylindrical section 25 and second substantially cylindrical section 26 are provided with longitudinal projections 20 and longitudinal recesses 19 being an extension of longitudinal projections 20 and longitudinal recesses 19 arranged in a tapered section 24 of the sliding element 18.

[0085] It should be also noted that a shape of the longitudinal projections 20 of one sliding element 18 corresponds to a shape of the longitudinal recesses 19 of the other sliding element 18.

[0086] Further, one sliding element 18 and the other sliding element 18 are partly-hollow. Partly-hollow denotes that there is a space in without the core 23 along a length of the sliding element 18 from one of the ends 21, 22, for example a half of the total length. Thus, an assembly of one sliding element 18 and the other sliding element 18 is feasible.

[0087] A plurality of surfaces of longitudinal projections 20 define a circle in a cross section taken in a perpendicular direction to the longitudinal axis of the sliding element 18. A plurality of surfaces of longitudinal projections 20 of one sliding element 18 defines a circle with diameter D in any cross section taken in a perpendicular direction to the longitudinal axis of one sliding element 18. A plurality of surfaces of longitudinal projections 20 of the other sliding element 18 defines a circle with diameter D in any cross section taken in a perpendicular direction to the longitudinal axis of the other sliding element 18.

[0088] The diameter D is different in different cross sections of one sliding element 18 taken in a perpendicular direction to the longitudinal axis of the sliding element 18. It should be noted that at first end 21 the diameter D is the smallest. In the same time, at top end 22 the diameter D is the largest. Thus, along the tapered portion 23 the diameter D increases. Further, along first substantially cylindrical section 25 and second substantially cylindrical section 26 the diameter D is constant. The above described relationship is the same for diameter D of the other sliding element 18.

[0089] An assembly of one sliding element 18 and the other sliding element 18 according to the present invention is illustrated in FIG. 11a-11c. The assembly is performed by engaging, more specifically by sliding, of one sliding element 18 and the other sliding element 18. A direction of sliding movements for assembly the core pin assembly 17 is indicated by two arrows in FIGS. 11a and 11b. During assembly, the longitudinal projections 20 of one sliding element 18 are positioned in the longitudinal recesses 19 of the other sliding element 18.

[0090] FIG. 12 presents a front view of assembled core pin assembly 17 according to the present invention. The core pin assembly 17 comprises first end 28 and second end 29. First end 28 and second end 29 of the core pin assembly 17 are axially opposite. At both ends 28, 29 there are provided substantially cylindrical sections 27 of the core pin assembly 17. Substantially cylindrical sections 27 of the core pin assembly 17 are formed by substantially cylindrical sections 25, 26 of the sliding elements 18, 18 in the assembled core pin assembly 17.

[0091] With reference to FIG. 12, a length L of the substantially cylindrical sections 27 of the assembled core pin assembly 17 preferably falls within range 1/20 and a total height H of the core pin assembly 17. More particularly, the length L falls within range 1/10 and of a total height H of the core pin assembly 17.

[0092] It should be understood that a length of substantially cylindrical sections 27 of the core pin assembly 17 corresponds to a length of substantially cylindrical portions 15, 16 of the hole 9 as presented in FIG. 8.

[0093] In a particular embodiment a length L of the substantially cylindrical section 27 at first end 28 and at second end 29 of the core pin assembly 17 are equal.

[0094] In another particular embodiment a length L of the substantially cylindrical section 27 at first end 28 and at second end 29 of the core pin assembly 17 have different values.

[0095] An external surface of the core pin assembly 17 is formed by a plurality of outermost surfaces of the longitudinal projections 20 of one sliding element 18 and the longitudinal projections 20 of the other sliding element 18.

[0096] Now reference is made to FIGS. 13a and 13c. FIG. 13a shows a cross section view at first end 28 of the assembled core pin assembly 17 and FIG. 13c shows a cross section view at second end 29 of the assembled core pin assembly 17. For the purpose of clarity, diameters of the sliding elements 18, 18 at first end 28 are denoted with, respectively, D.sub.28, D.sub.28. Diameters of the sliding elements 18, 18 at second end 29 are denoted with, respectively, D.sub.29, D.sub.29.

[0097] The above described preferred embodiment of the core pin assembly 17 ensures that in said cross sections a plurality of surfaces of the longitudinal projections 20 of one sliding element 18 define circles with diameters D.sub.28, D.sub.29. In the same cross sections a plurality of surfaces of the longitudinal projections 20 of the other sliding element 18 define circles with diameters D.sub.28, D.sub.29. It should be understood that at first end 28 of the core pin assembly 17 the diameter D.sub.28 is larger than diameter D.sub.28 (FIG. 13a). At the second end 29 the diameter D.sub.29 is smaller than diameter D.sub.29 (FIG. 13c).

[0098] Therefore, there is a cross section taken in a perpendicular direction to the longitudinal axis of the core pin assembly 17, in which diameter D and diameter D are equal (FIG. 13b). In a preferred embodiment said cross section is a central cross section. FIG. 13b shows a central cross section in the central part of the assembled core pin assembly 17. The central cross section of the core pin assembly 17 is preferably taken in the middle between first end 28 and second end 29 of the core pin assembly 17.

[0099] A method for producing a pivot shaft housing is performed with using of the mold assembly 30 presented in FIG. 14. The mold assembly 30 comprises a mold 31 for containing a material and a core pin assembly 17. The mold 31 is advantageously provided with a cavity 34 for containing the material The mold 31, in the illustrated embodiment, further comprises first mold component 32 and second mold component 33 (only one mold component 32 is presented in FIG. 14). First mold component 32 is detachably coupled with second mold component 33. When first mold component 32 is coupled with second mold component 33, the mold cavity 34 is defined between two mold components 32, 33.

[0100] Further, the core pin assembly 18,18 is assembled. The sliding elements 18,18 are assembled by sliding, namely one sliding element 18 is slided into the other sliding element 18 so as to form the core pin assembly 17. During assembly, the longitudinal projections 20 of one sliding element 18 are positioned in the longitudinal recesses 19 of the other sliding element 18 as presented in FIG. 11a-11c.

[0101] In one embodiment the core pin assembly 17 is positioned into the mold cavity 34, when the two mold components 32, 33 are separated from each other. When the core pin assembly 17 is already positioned in the mold cavity 34, first mold component 32 and second mold component 33 are coupled, so as to close the mold cavity 34 with the core pin assembly 17 therein. A material is further provided into the mold cavity 34 for forming the pivot shaft housing 6.

[0102] In another embodiment, the core pin assembly is inserted into the mold cavity 34 after mold components 32, 33 being coupled. The sliding elements 18,18 are slided into each other after mold components 32, 33 being coupled. Thus, the sliding elements 18, 18 are assembled into the core pin assembly in the mold cavity 34.

[0103] Preferably, the mold assembly 30 further comprises material feeding means (not shown) for feeding a material into the mold cavity 34. The material preferably includes a plastic material. In a preferred embodiment plastic material is injected into the mold cavity 34. In another embodiment material is metal, e.g. cast iron.

[0104] During injection of material into the mold cavity 34, the pivot shaft housing 6 is formed. Forming of the pivot shaft housing 6 is further described.

[0105] The material is provided into the mold cavity 34 containing the core pin assembly 17. The inner surface of the hole 9 of the pivot shaft housing 6 is formed by the external surface of the core pin assembly 17. The external surface is formed by outermost surfaces of the longitudinal projections 20 of the sliding elements 18, 18. A plurality of outermost surfaces of the longitudinal projections 20 of one sliding element 18 and the other sliding element 18 in the core pin assembly 17 form a plurality of surfaces of the spatial structures 14 of the hole 9 of the pivot shaft housing 6. More specifically, the tapered sections 24 of one sliding element 18 and the other sliding element 18 of the core pin assembly 17 form the slant spatial structures 14 of the hole 9. The substantially cylindrical sections 27 situated at both ends 28, 29 of the core pin assembly 17 form, respectively, first substantially cylindrical portion 15 and second substantially cylindrical portion 16 of the hole 9 of the pivot shaft housing 6.

[0106] After injection of the material, the material is curing in the mold cavity 34. When curing of the material is completed, the two mold components 32, 33 are separated from each other. In the next step, the core pin assembly 17 is removed from the hole 9 of the pivot shaft housing 6. Said removal includes sliding out of one sliding element 18 and the other sliding element 18 from one end 10 and the other end 11 of the through hole 9. A direction of sliding movements for removing the sliding elements 18, 18 from the mold cavity 34 is indicated by two arrows in FIG. 14. In a variant, it is only after removal of the core pin assembly 17 as described above, that the pivot shaft housing 6 is removed from the mold cavity 34.

[0107] In a preferred embodiment the pivot shaft housing 6 is molded in one piece.

[0108] FIG. 3 presents a front view of the pivot shaft housing 6 with the pivot shaft 8 supported in the pivot shaft housing 6 according to the present invention. The pivot shaft 8 is supported in the through hole 9. The hole 9 comprises first substantially cylindrical portion 15 and second substantially cylindrical portion 16 at one end 10 and at the other end 11 of the hole 9, respectively.

[0109] Now reference is made to FIGS. 4a and 4c. FIG. 4a shows a cross section view at one end 10 of the hole 9 of the pivot shaft housing 6 supporting the pivot shaft 8 therein. FIG. 4c shows a cross section view at the other end 11 of the hole 9 of the pivot shaft housing 6 supporting the pivot shaft 8 therein

[0110] In FIGS. 4a and 4c there are shown grooves 12 and ribs 13 of the pivot shaft housing 6 supporting the pivot shaft 8. In the illustrated preferred embodiment, the hole 9 comprises ten spatial structures 14. Said ten spatial structures 14 define five grooves 12 and five ribs 13 at one end 10 of the hole 9 (FIG. 4a). In the same time, ten spatial structures 14 define five grooves 12 and five ribs 13 at the other end 11 of the hole 9 (FIG. 4c). It is shown that ribs 13 of the pivot shaft housing 6 act as a bearing for the pivot shaft 8 at first substantially cylindrical portion 15 and second substantially cylindrical portion 16.

[0111] Therefore, in said cross sections of the hole 9 there are defined two circles. The first circle has, respectively a first diameter D.sub.1 at one end 10 of the hole 9 and a first diameter D.sub.1 at the other end 11 of the hole 9. Further, the second circle has second diameter D.sub.2 at one end 10 of the hole 9 and second diameter D.sub.2 at the other end of the hole 9. First diameters D.sub.1, D.sub.1 and second diameters D.sub.2, D.sub.2 are constant along, respectively, whole first substantially cylindrical portion 15 and second substantially cylindrical portion 16. Therefore, a diameter of the pivot shaft 8 and first diameters D.sub.1, D.sub.1 are equal along whole first substantially cylindrical portion 15 and second substantially cylindrical portion 16.

[0112] Therefore, substantially cylindrical portions 15, 16 at one end 10 and the other end 11 of the hole 9 are particularly advantageous. Substantially cylindrical portions eliminate a necessity of using of additional bushes at both ends 10, 11 of the hole 9 to support the pivot shaft 8 in the pivot shaft housing 6.

[0113] In addition, substantially cylindrical portions 15, 16 at one end 10 and at the other end 11 have an advantage of minimizing of a coaxial shaft play between the pivot shaft housing 6 and the pivot shaft 8. Minimizing of a coaxial shaft play results in a high operating stability of the pivot shaft 8 supported by the pivot shaft housing 6.

[0114] FIG. 4b shows a central cross section in the central part of the hole 9 of the pivot shaft housing 6 supporting the pivot shaft 8 therein. As mentioned above, in the central cross section first diameter D.sub.1 and second diameter D.sub.2 are equal. In the central cross section first diameter D.sub.1 and second diameter D.sub.2 are equal. Thus, in the central cross section there is defined single circle with a diameter larger than a diameter of the pivot shaft 8. Thus, an annular play 35 is provided between an circumferential surface of the pivot shaft 8 and the inner surface of the hole 9.

[0115] FIG. 5 presents a schematic cross-section view of the pivot shaft housing 6 supporting the pivot shaft 8 therein taken in a direction of the longitudinal axis A of the hole 9. As can be seen in FIG. 5, there is provided an annular play 35 between an circumferential surface of the pivot shaft 8 and an internal surface of the hole 9. The annular play 35 extends between first substantially cylindrical portion 15 and second substantially cylindrical portion 16 supporting the pivot shaft 8.

[0116] Thus, a friction force between the pivot shaft housing 6 and the pivot shaft 8 rotating therein is reduced. Friction force reduction provides a higher level of a pivot shaft torque inside the pivot shaft housing 6. Therefore, easy rotatability of the pivot shaft 8 in the pivot shaft housing 6 is obtained.

[0117] Advantageously the grooves 12 of the pivot shaft housing 6 contain a lubricant for even more improving rotation properties.

[0118] The described invention is not restricted to the embodiments shown but is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims. All the details may further be replaced with other technically equivalent elements.

LIST OF REFERENCE NUMBERS

[0119] (1) wiper module [0120] (2) wiper motor [0121] (3) link assembly [0122] (4) crank [0123] (5) frame tube [0124] (6) pivot shaft housing [0125] (7) housing part of the pivot shaft housing [0126] (8) pivot shaft [0127] (9) through hole [0128] (10) one end of the through hole [0129] (11) the other end of the through hole [0130] (12) groove of the housing [0131] (13) rib of the housing [0132] (14) spatial structure [0133] (15) first substantially cylindrical portion of the hole [0134] (16) second substantially cylindrical portion of the hole [0135] (17) core pin assembly [0136] (18) one sliding element [0137] (18) the other sliding element [0138] (19) longitudinal recess of the sliding element [0139] (20) longitudinal projection of the sliding element [0140] (21) first end of the sliding element [0141] (22) top end of the sliding element [0142] (23) core of the sliding element [0143] (24) tapered section of the sliding element [0144] (25) first substantially cylindrical section of the sliding element [0145] (26) second substantially cylindrical section of the sliding element [0146] (27) substantially cylindrical section of the core pin assembly [0147] (28) first end of the core pin assembly [0148] (29) second end of the core pin assembly [0149] (30) mold assembly [0150] (31) mold [0151] (32) first mold component [0152] (33) second mold component [0153] (34) mold cavity [0154] (35) annular play