Gear wheel, steering device having such gear wheel, and method for producing such gear wheel

Abstract

The invention relates to a gearwheel (1, 27, 29, 35) having an inner part (2) made of metal and an outer part (3) made of plastic, the outer part (3) having a ring gear (4) and the outer part (3) being injection molded onto the inner part (2), the outer part (3) having a plurality of injection molded sections (7), the injection-molded sections are formed on a side face (8) of the embedded part (2), which side face is oriented transversely or perpendicularly to the central longitudinal axis (5). In order to be able to produce the gearwheel (1, 27, 29, 35) in a cost-effective manner and to have sufficient physical properties in terms of its load-carrying capacity and service life, the gearwheel is characterized in that a plurality of spray casting sections (7) are spaced apart from one another on a side face (8) of the embedded part (2), and a side section (9) of the embedded part (2) between the adjacent spray casting sections (7) is exposed.

Description

Technical Field

[0001] The invention relates to a gear having an inner part made of metal and an outer part made of plastic, wherein the outer part has a toothed ring with a plurality of toothings directed radially outward relative to a central longitudinal axis of the gear, and the outer part is injection-molded onto the inner part, wherein the outer part has a plurality of injection-molded sections which are formed on side surfaces of the inner part which are oriented transversely or perpendicularly to the central longitudinal axis. The invention also relates to a steering device for a vehicle having such a gear and a method for producing such a gear. Background Art

[0002] Such a gear is known from EP 2 427 145 A1, wherein a plurality of injection-molded segments merge with one another and form a continuous ring on the side of the inlay. Summary of the invention

[0003] The object of the invention is to further develop a gear wheel, a steering device and / or a method of the type mentioned at the outset so that the gear wheel can be produced in a cost-effective manner and has adequate physical properties with regard to its load-bearing capacity and service life. Preferably, the flow path of the plastic used to produce the outer part can be reduced. In particular, alternative embodiments are to be provided.

[0004] The object of the invention is achieved by a gear wheel according to claim 1 and / or by a deflection device according to claim 10 and / or by a method according to claim 11. Preferred developments of the invention can be found in the dependent claims and in the following description.

[0005] The gear has an inner part made of metal and an outer part made of plastic. The metal can be steel or aluminum. The plastic can be unreinforced or reinforced, in particular fiber-reinforced. The gear is preferably constructed in two parts. Here, the inner part forms the first part or first component of the gear and the outer part forms the second part or second component of the gear. Preferably, the gear is constructed for use in a steering device of a vehicle. The outer part has or forms a ring gear with a plurality of teeth pointing radially outward relative to the central longitudinal axis of the gear. In particular, the gear is constructed as a cylindrical gear or a helical gear or a worm gear. The toothing of the outer part can be constructed as a spur gear or a helical gear.

[0006] The outer part is injection molded onto the inner part. As a result, the outer part has a plurality of injection-cast sections. In particular, the outer part is constructed integrally with the ring gear and the injection-cast sections. Therefore, the injection-cast sections and the ring gear can preferably be combined with each other in a material-fitting manner to form a single component, namely the outer part. The injection-cast sections are constructed on the side of the inner part that is oriented transversely or perpendicular to the central longitudinal axis of the gear. In particular, all injection-cast sections are formed and / or arranged on the same side of the inner part. Preferably, a shape fit between the outer part and the inner part, in particular one-sided or two-sided in the axial direction of the central longitudinal axis, is achieved by means of the injection-cast sections.

[0007] According to the invention, a plurality of injection-molded sections are spaced apart from one another on a side surface of the inner insert part, wherein side sections of the side surface of the inner insert part between adjacent injection-molded sections are exposed.

[0008] Advantageously, the flow path of the plastic used to form the outer part is reduced. This can improve the supply of holding pressure during injection molding of the outer part. In addition, a small amount of plastic material can be used to form the outer part. In particular, alternative embodiments are provided.

[0009] In particular, the injection-cast sections on the side of the inlay part do not merge with each other. Therefore, no joint seams between the injection-cast sections are formed on the side. Alternatively, web-shaped or strip-shaped connecting sections made of plastic can be formed between the adjacent injection-cast sections to form the outer part. As a result, the adjacent injection-cast sections are partially merged with each other by means of corresponding connecting sections on the side. But at the same time, in this embodiment, the side sections between the adjacent injection-cast sections are also exposed. In particular, the web-shaped or strip-shaped connecting section transitions into the gear ring of the outer part. The web-shaped or strip-shaped connecting section is preferably constructed in a curved or ring-shaped segment.

[0010] Preferably, the side or another side of the inner part facing away from the side with the injection-molded section is not, in particular neither completely nor partially, covered by the plastic of the outer part. Thus, the plastic of the outer part can be arranged only on a single side to form the injection-molded section and around the circumference of the inner part to form the toothed ring.

[0011] Alternatively, the plastic of the outer part can surround the periphery of the inner part, wherein not only the side of the inner part but also the side or another side of the inner part facing away from the side is covered by the plastic of the outer part. Thus, in this embodiment, the shape fit between the outer part and the inner part is improved.

[0012] The embedded part can be configured as a hub or a shaft. In addition, the embedded part can have a cylindrical outer circumference or a non-circular, preferably polygonal outer circumference. The inner circumference of the outer part abutting against the outer circumference of the embedded part is configured to correspond in shape to the outer circumference of the embedded part. In particular, the embedded part is configured as a cylindrical hub or a disc-shaped hub or a hub having an inner cylinder, an outer cylinder and an annular disk, wherein the inner cylinder is connected to the outer cylinder via the annular disk. Here, the annular disk can connect the axial end of the inner cylinder relative to the central longitudinal axis with the axial end of the outer cylinder, whereby the embedded part has an annular recess extending in the axial direction of the central longitudinal axis. Here, the side with the injection-casting section is arranged on the side of the embedded part that is away from the side with the recess. In particular, a U-shaped cross section is formed in the transition area from the inner cylinder through the annular disk to the outer cylinder.

[0013] The inner part can be configured as a sintered part or a cold extruded part or a turned part. In particular, the inner part is made of steel or aluminum.

[0014] According to the improved scheme, the injection-casting sections each have a basic shape of a triangle and / or a triangle. Here, the corner of the corresponding injection-casting section points radially inward toward the central longitudinal axis. In particular, the radially inwardly pointing corner is configured as the first corner of the corresponding injection-casting section, wherein the corresponding injection-casting section has a second corner and a third corner for forming a basic shape of a triangle and / or a triangle. These corners may have an acute angle or these corners may be rounded. The injection-casting section preferably has two side edges, wherein an obtuse angle radially open outward relative to the central longitudinal axis is formed between the two side edges. In particular, looking radially inward, the two side edges merge into a corner or a first corner. The two ends of the two side edges pointing radially outward are connected to each other with the edge section of the corresponding injection-casting section. Therefore, the edge section can merge with the first side edge to the second corner, and the edge section can merge with the second side edge to the third corner. In particular, a plurality of injection-molded segments are arranged and / or formed so as to be evenly distributed in a circumferential direction about the central longitudinal axis.

[0015] According to another embodiment, the inlay part has a central through-opening and / or an axis. In particular, the axis is guided through the through-opening and / or fixed in the through-opening. The injection-molded sections, in particular the corners of the individual injection-molded sections, are spaced apart from the through-opening and / or the axis. Preferably, an annular side area of ​​the side of the inlay part between the injection-molded section and the through-opening and / or the axis is exposed. Thus, the annular side area of ​​the inlay part, which is located radially inwards with respect to the central longitudinal axis, is not used to form a plastic cover of the outer part.

[0016] Preferably, the radially inwardly pointing corners of the respective injection-molded sections are curved or configured as arcs. In this case, the corners may have a radius such that an imaginary full circle with this radius is completely located on the side surface of the inline part. The imaginary full circle is preferably closed flush with the outer circumference of the inline part. The full circle may correspond to the position of the impact surface for injection molding the respective injection-molded section. The center point of the full circle may correspond to the position or orientation of the injection-molding point, in particular to the position of the outlet portion of the hot runner distributor for injection molding the respective injection-molded section. Preferably, the positioning or position of the injection-molding point and / or the hot runner distributor on the side surface of the inline part depends on the diameter of the gear and the hot runner distributor, in particular the diameter of the nozzle of the hot runner distributor.

[0017] According to another embodiment, the gear ring has an annular rim section. Preferably, the gear ring is formed by a rim section and a toothing extending radially outward from the rim section relative to the central longitudinal axis. Here, the inner circumference of the rim section is arranged on the outer circumference of the embedded part, in particular by means of a form fit between the inner circumference of the rim section and the outer circumference of the embedded part. As an example, the form fit can be achieved by means of knurling formed on the outer circumference of the embedded part. The outer circumference of the rim section can correspond to the root circle diameter of the toothing of the gear ring.

[0018] In particular, the edge section of the respective injection-molded section pointing radially outward relative to the central longitudinal axis is arranged at least partially or completely between the inner periphery of the rim section and the tooth root diameter. Thus, the respective injection-molded section projects radially beyond the outer periphery of the inlay part relative to the central longitudinal axis. In particular, the edge section projects radially outward relative to the central longitudinal axis beyond the tooth root diameter into the region of the toothing, preferably into the region of the tooth root of the toothing.

[0019] According to a further development, the edge sections of the individual injection-molded sections are designed as arcs. Here, the edge sections of all injection-molded sections are arranged on a common, in particular imaginary circle and are concentric with the central longitudinal axis. The thickness of the individual injection-molded sections can at least partially decrease in the direction of the edge sections and / or in the region of the edge sections. For example, the thickness of the individual injection-molded sections decreases continuously at least in certain areas.

[0020] According to another embodiment, the edge section of each injection-molded section has a streamlined profile having at least one chamfer and / or at least one rounded edge. In particular, due to the streamlined profile, the flow of plastic is improved during injection molding for forming the outer part. The streamlined profile preferably has a first rounded edge with a first radius, wherein the first radius is curved convexly outward. The streamlined profile in particular has a second rounded edge with a second radius, wherein the second radius is curved concavely inward. Here, the second rounded edge is constructed between the rim section and the first rounded edge. The first radius transitions to the second radius. The first radius and / or the second radius can be constructed as a quarter circle.

[0021] According to a further development, the outer part has three injection-molded sections or four injection-molded sections. In the case of three injection-molded sections, the injection-molded sections are arranged at an angle of 120° to one another about the central longitudinal axis. In the case of four injection-molded sections, the injection-molded sections are arranged at an angle of 90° to one another about the central longitudinal axis. The injection-molded sections are thus formed uniformly in a circumferential direction about the central longitudinal axis.

[0022] A steering device for a vehicle, in particular a motor vehicle, having a gear according to the invention is particularly advantageous. The steering device can be designed as a steer-by-wire device. The toothing of the ring gear is designed as a helical toothing and interacts with at least one worm wheel or at least one worm shaft. The gear can ensure a reliable transmission of force and torque. At the same time, a weight-saving and cost-effective design can be achieved.

[0023] In addition, a method for manufacturing a gear according to the present invention is advantageous. Here, the inner part is inserted into an injection mold and the outer part is injection molded by means of a hot runner distributor. In contrast to a cold runner distributor, the hot runner distributor can improve the supply of holding pressure during injection molding. The hot runner distributor has a plurality of outlet locations for forming the plastic of the outer part, the number of which depends on the number of injection-molded sections of the outer part to be formed. In particular, the hot runner distributor has a plurality of nozzles, wherein each nozzle has or forms an outlet location. These outlet locations point to the side of the inner part so as to form the injection-molded section and the gear ring of the outer part. In particular, these outlet locations are arranged facing the injection-molding point or are opposite to the injection-molding point. Here, the injection-molding point can correspond to the center point of an imaginary full circle on the side, wherein, after the corresponding injection-molding section is manufactured, the imaginary full circle is located in the injection-molding section and / or is closed flush with the outer circumference of the inner part and / or is closed flush with the radially inwardly directed corner of the injection-molding section.

[0024] The gear manufactured according to the method according to the invention is in particular the gear according to the invention described above. Preferably, the method is improved according to the design solution explained in conjunction with the gear according to the invention described herein. In addition, the gear described herein can be improved according to the design solution explained in conjunction with the method. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention is explained in more detail below with reference to the accompanying drawings. Here, the same reference numerals represent the same, similar or functionally identical components or elements. Among them:

[0026] Figure 1 shows a first perspective side view of a first gear wheel according to the present invention,

[0027] Figure 2 Shown according to Figure 1 A second perspective side view of the first gear according to the present invention,

[0028] Figure 3 Shown according to Figure 1 and Figure 2 A side sectional view of a first gear according to the present invention,

[0029] Figure 4 Shown according to Figures 1 to 3 Another perspective side view of a first gear according to the present invention, and the first gear has a schematically shown hot runner distributor,

[0030] Figure 5 shows a first perspective side view of a second gear wheel according to the present invention,

[0031] Figure 6 Shown according to Figure 5 A second perspective side view of a second gear according to the present invention,

[0032] Figure 7 shows a perspective side view of a third gear according to the present invention,

[0033] Figure 8 Shown according to Figure 7 A side sectional view of a third gear according to the present invention,

[0034] Fig. 9 A side cross-sectional view of another gear according to the present invention is shown. DETAILED DESCRIPTION

[0035] Figure 1 A first perspective side view of a first gear wheel 1 according to the invention is shown. The gear wheel 1 is designed for a steering device (not shown in detail here), for example a steer-by-wire device. In this exemplary embodiment, the gear wheel 1 is implemented as a two-component gear wheel. For this purpose, the gear wheel 1 has an inner part 2 and an outer part 3.

[0036] The inner part 2 is made of metal and the outer part 3 is made of plastic. The outer part 3 has a toothed ring 4, wherein the toothed ring 4 has a plurality of toothings 6 pointing radially outwards relative to the central longitudinal axis 5 of the gear wheel 1. In this exemplary embodiment, the toothing 6 of the outer part 3 is designed as a helical toothing. For the sake of greater clarity, not all toothings 6 are marked with reference numerals.

[0037] The outer part 3 is injection molded around the outer circumference of the inner part 2. In addition, the outer part 3 has a plurality of injection-cast sections 7. In this embodiment, the outer part 3 has a total of three injection-cast sections 7. The injection-cast sections 7 are formed in one piece or in one piece with the ring gear 4. The inner part 2 has a side surface 8 extending at a right angle to the central longitudinal axis 5. All injection-cast sections 7 are arranged on the side surface 8 or are located on the side surface 8. Here, the plurality of injection-cast sections 7 are evenly distributed along the circumferential direction around the central longitudinal axis 5, that is, distributed at an angle of 120° to each other. With the help of these injection-cast sections 7, the inner part 2 is fixed in at least one axial direction with respect to the central longitudinal axis 5.

[0038] The injection-molded sections 7 formed on the side surface 8 are spaced apart from one another. In the present embodiment, the injection-molded sections 7 do not merge directly into one another. Instead, according to this example, the side sections 9 of the side surface 8 located between the injection-molded sections 7 that are directly adjacent in the circumferential direction about the central longitudinal axis 5 are completely exposed. Since three injection-molded sections 7 are formed here, three exposed side sections 9 are produced accordingly in the present embodiment.

[0039] The injection-casting sections 7 each have a triangular and / or triangular basic shape. Accordingly, the injection-casting sections 7 have a first corner 10, a second corner 11 and a third corner 12. The first corner 10 of each injection-casting section 7 points radially inward toward the central longitudinal axis 5. In the present embodiment, the first corner 10 is rounded. In contrast, in the present embodiment, the second corner 11 and the third corner 12 in the present embodiment both have acute angles.

[0040] The injection molded section 7 has two side edges 13, 14. Here, an obtuse angle is formed between the two side edges 13, 14, which opens radially outwards from the first corner 10 relative to the central longitudinal axis 5. In other words, the two side edges 13, 14 merge at the first corner 10, viewed in the radially inward direction.

[0041] The two radially outwardly directed ends of the two side edges 13, 14, or the two corners 11, 12, are connected to one another with the edge section 15 of the corresponding injection-molded section 7. Thus, the edge section 15 and the first side edge 13 merge at the second corner 11, and the edge section 15 and the second side edge 14 merge at the third corner 12.

[0042] In the present embodiment, the edge sections 15 of the individual injection-molded sections 7 are designed to be arcuate. In contrast, according to this example, the side edges 13, 14 are designed to be straight. The arcuate edge sections 15 of all injection-molded sections 7 are located on a common circle, not shown here or imaginary, and are arranged concentrically with the central longitudinal axis 5.

[0043] In the present embodiment, the inner part 2 is configured as a hub having an annular disk shape. Accordingly, the inner part 2 has a central through-opening 16. By way of example, by inserting or partially passing a shaft (not shown in detail here) through the through-opening 16, the gear 1 can be pushed or pressed onto the shaft.

[0044] In the present exemplary embodiment, the injection-molded section 7, or more precisely the first corner 10 of each injection-molded section 7, is spaced apart from the through-opening 16. As a result, the annular side region 17 of the side surface 8 of the inner part 2, which is located between the injection-molded section 7 and the through-opening 16, is exposed. Therefore, the annular side region 17 located on the inside in the radial direction relative to the central longitudinal axis 5 and the side section 9 of the inner part 2 are not used to form a plastic cover for the outer part 3.

[0045] The toothed ring 4 of the outer part 3 has an annular rim section 18. The toothed ring 4 is therefore composed of the rim section 3 and the toothing 6 extending radially outward from the rim section 3 relative to the central longitudinal axis 5. Here, the inner circumference of the annular rim section 18 is located on the outer circumference of the inner part 2. A form fit, not shown in detail here, is formed between the inner circumference of the rim section 18 and the outer circumference of the inner part 2 for fixing the rim section 18 on the outer circumference of the inner part 2. The outer circumference of the rim section 18 also forms the root circle diameter of the toothing 6 of the toothed ring 4.

[0046] In the present embodiment, the edge sections 15 of the respective injection-molded sections 7 pointing radially outward relative to the central longitudinal axis 5 are arranged at least partially between the inner periphery of the rim section 18 and the root diameter of the toothing 6 of the toothed ring 4. The respective injection-molded sections thus protrude radially beyond the outer periphery of the inner part 2 relative to the central longitudinal axis 5. According to the example, the edge sections 15 protrude radially outward relative to the central longitudinal axis 5 beyond the root diameter into the region of the toothing 6 or into the region of the tooth roots of the toothing 6.

[0047] Figure 2 Shown according to Figure 1 1 is a second perspective side view of the first gear wheel 1 according to the invention. The other side 19 of the inner part 2 can be seen, which faces away from the side 8 with the injection-molded section 7 which is not visible here. In the present embodiment, this other side 19 is not covered by the plastic of the outer part 3. Therefore, the plastic of the outer part 3 is only arranged on the outer part according to the embodiment. Figure 1The outer part 3 is disposed on the side 8 shown in the figure to form the injection-molded section 7, and is arranged around the outer circumference of the inner part 2 to form the gear ring 4. Alternatively, an embodiment in which the plastic of the outer part 3 surrounds or encloses the outer circumference of the inner part 2 so that the plastic of the outer part 3 is also arranged on the other side 19 is feasible. This can improve the form fit between the outer part 3 and the inner part 2.

[0048] Figure 3 Shown according to Figure 1 and Figure 2 1 is a side sectional view of the first gear wheel 1 according to the invention. The transition of the injection molded section 7 to the gear ring 4 can be clearly seen. In the present embodiment, the edge section 15 of each injection molded section 7 has a streamlined profile 20. With the help of this streamlined profile 20, the flow of the plastic during the injection molding for forming the outer part 3 is improved.

[0049] In the present embodiment, the streamlined contour 20 has a first rounded edge 21 with a first radius, wherein the first radius is curved convexly outward. In addition, the streamlined contour 20 in this example has a second rounded edge 22 with a second radius, wherein the second radius is curved concavely inward. Here, the second rounded edge 22 is formed between the rim section 18 and the first rounded edge 21. The first radius of the first rounded edge 21 transitions to the second radius of the second rounded edge 22, wherein according to this example, the first rounded edge 21 and the second rounded edge are each designed as a quarter circle.

[0050] In the present exemplary embodiment, the thickness of the individual injection-molded sections 7 is constant. Alternatively, the thickness of the individual injection-molded sections 7 can at least partially decrease in the direction of the edge section 15 and / or in the region of the edge section 15 .

[0051] Figure 4 Shown according to Figures 1 to 3 Another perspective side view of the first gear 1 according to the present invention, and the first gear has a schematically shown hot runner distributor 23.

[0052] To produce the gear 1, the inner part 2 is inserted into an injection mold (not shown in detail here). The outer part 3 is then injection molded by means of a hot runner distributor 23. For this purpose, the hot runner distributor 23 has a plurality of, here for example three, outlet locations 24 for the plastic forming the outer part 3, depending on the number of injection-molded sections 7 of the outer part 3 to be formed.

[0053] In the present embodiment, the hot runner distributor 23 has a total of three nozzles 25, which are only schematically shown, wherein each nozzle 25 provides an outlet portion 24. The outlet portion 24 or nozzle 25 is directed toward the side 8 of the inner part 2 to form the injection molding section 7 of the outer part 3 and the gear ring 4. For this purpose, the outlet portion 24 or nozzle 25 is respectively arranged opposite to the injection molding point.

[0054] According to the example, such a spraying point corresponds to the center point of a full circle 26, which is imaginary on the side surface 8 or schematically shown here on the upper side of the spray-cast section 7. After the production of the corresponding spray-cast section 7, this full circle 26 is located within the corresponding spray-cast section 7. According to the present embodiment, the full circle 26 is closed flush with the outer circumference of the inner part 2 and flush with the first corner 20 of the corresponding spray-cast section 7 pointing radially inwards. The first corner 20 of the respective spray-cast section 7 pointing radially inwards is accordingly designed as an arc. In the present embodiment, the first corner 20 therefore has a radius that overlaps with the radius of the full circle 26. The full circle 26 corresponds to the position on the side surface 8 of the inner part 2 for injection molding the corresponding spray-cast section 7 and forming the impact surface of the outer part 3.

[0055] Figure 5 A first perspective side view of a second gear 27 according to the invention is shown. The structure and mode of operation of the second gear 27 largely correspond to those according to Figures 1 to 4 The first gear wheel 1 of the present invention. The same features have the same reference numerals as before. In this respect, in order to avoid repetitions, reference is also made to the previous description.

[0056] In contrast to the gear 1, the gear 27 shown here has an inner part 2 with a non-circular outer circumference. Correspondingly, the inner circumference of the outer part 3, more precisely the inner circumference of the toothed ring 4 with the rim section 18, is designed to be non-circular. This improves the form fit between the inner part 2 and the outer part 3.

[0057] In the present embodiment, a plurality of projections 28 are arranged or formed on the side surface 8. The projections 28 are each arranged in the region of the side surface section 9 and are each located in the middle between two adjacent injection-molded sections 7. The projections 28 extend parallel to the central longitudinal axis 5. According to this example, the projections 28 have a height that is equal to the thickness or maximum thickness of the injection-molded section 7. Furthermore, the projections 28 have, for example, a truncated cone shape.

[0058] The inner part 2 for forming the gear wheel 27 can be inserted into an injection mold (not shown in detail here) in a predetermined and aligned manner by means of the projections 28. For this purpose, the injection mold has receptacles that are designed corresponding to the projections 28 and into which the projections are received in a form-fitting manner. In particular, in the case of an inner part 2 with a non-circular outer circumference as here, such a directional insertion of the inner part 2 into the injection mold is advantageous for ensuring a reproducible orientation of the inner part 2 relative to the outer part 3 over which it is injection-molded, in particular with an improved supply of holding pressure during the injection molding of the outer part 3.

[0059] Figure 6 Shown according to Figure 5 27 according to the present invention. The non-circular contour of the outer circumference of the inner part and the correspondingly constructed non-circular contour of the inner circumference of the ring gear 4, more precisely the rim section 18, can be clearly seen here.

[0060] In the present embodiment, the other side surface 19 is also not covered by the plastic of the outer part 3 .

[0061] Figure 7 The structure and operation of the further gear 29 largely correspond to those of the third gear 29 according to the invention. Figures 1 to 4 The first gear 1 or according to Figure 5 and Figure 6 The second gear 27. The same features have the same reference numerals as before. In this respect, in order to avoid repetition, reference is also made to the previous description.

[0062] Unlike the gear 1 and the gear 27, the gear 29 shown here has an inner part 2, wherein the inner part 2 according to the present embodiment has an inner cylinder 30, an outer cylinder 31 and an annular disk 32. The inner part 2 is constructed in one piece or in one piece. In addition, the inner cylinder 30 is connected to the outer cylinder 31 by means of the annular disk 32. Therefore, the annular disk 32 is arranged between the inner cylinder 30 and the outer cylinder 31.

[0063] Specifically, in the present embodiment, the annular section 32 connects the end of the inner cylinder 30 axially relative to the central longitudinal axis 5 to the axial end of the outer cylinder 31. Here, the annular section extends at a right angle to the central longitudinal axis 5. Therefore, according to the present embodiment, the inner part 2 has an annular recess 33 extending in the axial direction of the central longitudinal axis 5. Here, the side 8 with the injection-molded section 7, which is not visible here, is arranged on the side of the inner part 2 facing away from the side 34 with the recess 33.

[0064] Figure 8 Shown according to Figure 72 is a side sectional view of the third gear 29 according to the present invention. It can be clearly seen that a U-shaped cross section is formed in the region of the transition portion from the inner cylinder 30 through the annular disk 32 to the outer cylinder 31.

[0065] Fig. 9 A side sectional view of another gear 35 according to the invention is shown. The structure and mode of operation of this other gear 35 largely correspond to that according to Figure 7 and Figure 8 The third gear 29 of the present invention. The same features have the same reference numerals as before. In this respect, in order to avoid repetition, reference is also made to the description above.

[0066] Unlike the third gear 29, the other gear 35 shown here has a web-shaped or strip-shaped connecting section 36 between the adjacent injection-molded sections 7. In the present embodiment, the connecting section 7 is curved, more precisely, an annular segment-shaped structure. The connecting section 36 is made of the plastic of the outer part 3 and is configured as a component of the outer part 3. Therefore, the adjacent injection-molded sections 7 are partially merged with each other by means of the corresponding connecting sections 36 configured on the side 8 between these injection-molded sections. In addition, the connecting section 36 transitions to the toothed ring 4 of the outer part 3. The connecting section 36 is an integral or one-piece component of the outer part 3. But at the same time, for this other gear 35, the side sections 9 between the adjacent injection-molded sections 7 are also exposed.

[0067] In the embodiment according to the gear 35 shown here, the plastic of the outer part 3 surrounds the outer circumference of the inner part 2. Since the outer circumference of the inner part 2 is surrounded, according to this example, the plastic of the outer part 3 also abuts against the inner circumferential side of the outer cylinder 31. In addition, in this embodiment, the plastic of the outer part 3 extends into the recess 33 until it abuts against the annular disk 32. In this embodiment, the form fit between the outer part 3 and the inner part 2 is improved.

[0068] List of reference numerals:

[0069] 1 Gear

[0070] 2 Embedded part

[0071] 3 Outer part

[0072] 4 Ring gear

[0073] 5 Central longitudinal axis

[0074] 6 Teeth

[0075] 7 Spray casting section

[0076] 8 Side

[0077] 9 Side sections

[0078] 10 First corner

[0079] 11 Second corner

[0080] 12 Third corner

[0081] 13 Side edge

[0082] 14 Side edge

[0083] 15 Edge Segment

[0084] 16 Through opening

[0085] 17 Circular side area

[0086] 18 rim sections

[0087] 19 The other side

[0088] 20 Streamlined silhouette

[0089] 21 First rounded edge

[0090] 22 Second rounded edge

[0091] 23 Hot runner distributor

[0092] 24 Exit

[0093] 25 Nozzle

[0094] 26 full circle

[0095] 27 Gear

[0096] 28 bulge

[0097] 29 Gear

[0098] 30 Inner tube

[0099] 31 outer cylinder

[0100] 32 Ring disk

[0101] 33 recess

[0102] 34 Side

[0103] 35 Gear

[0104] 36 Connect the sections.

Claims

1. A gear (1, 27, 29, 35) having an inner part (2) made of metal and an outer part (3) made of plastic, wherein: The outer part (3) has a toothed ring (4) having a plurality of toothed sections (6) directed radially outward relative to a central longitudinal axis (5) of the gear wheel (1, 27, 29), and the outer part (3) is injection molded onto the inner part (2), wherein the outer part (3) has a plurality of injection-molded sections (7) which are formed on a side surface (8) of the inner part (2) which is oriented transversely or perpendicularly to the central longitudinal axis (5), characterized in that a plurality of the injection-molded sections (7) are spaced apart from one another on the side surface (8) of the inner part (2), and side sections (9) of the inner part (2) between adjacent injection-molded sections (7) are exposed.

2. The gear according to claim 1, characterized in that: The side (34) or the other side (19) of the inner part (2) facing away from the side (8) having the injection-molded section (7) is not covered, in particular neither completely nor partially, by the plastic of the outer part (3). Preferably, the inner part (2) is constructed as a cylindrical hub or a disk-shaped hub or a hub having an inner cylinder (30), an outer cylinder (31) and an annular disk (32), wherein the inner cylinder (30) is connected to the outer cylinder (31) by means of the annular disk (32).

3. The gear according to claim 1 or 2, characterized in that: The injection-cast segments (7) each have a triangular and / or triangular basic shape, wherein a corner (10) of each injection-cast segment (7) points radially inwardly toward the central longitudinal axis (5), preferably, the injection-cast segments (7) each have two side edges (13, 14), wherein an obtuse angle is formed between the two side edges (13, 14), and the obtuse angle is radially open outwardly relative to the central longitudinal axis (5), in particular, a plurality of the injection-cast segments (7) are arranged and / or constructed in a uniformly distributed manner in a circumferential direction around the central longitudinal axis (5).

4. A gear according to any one of the preceding claims, characterised in that The inlay part (2) has a central through-opening (16) and / or an axis, wherein the injection-cast section (7), in particular the corners (10) of each injection-cast section (7), are spaced apart from the through-opening (16) and / or the axis, and preferably, an annular side area (17) of the side surface (8) of the inlay part (2) between the injection-cast section (7) and the through-opening (16) and / or the axis is exposed.

5. The gear according to claim 3 or 4, characterized in that: The radially inwardly directed corners (10) of each injection-molded section (7) are curved or arc-shaped, and in particular, the corners (10) have a radius such that an imaginary full circle (26) having the radius is completely located on the side surface (8) of the embedded part (2), and preferably, the imaginary full circle (26) is closed flush with the outer circumference of the embedded part (2).

6. A gear according to any one of the preceding claims, characterised in that The gear ring (4) has an annular rim section (18), wherein the inner circumference of the rim section (18) is arranged on the outer circumference of the embedded part (2), and the outer circumference of the rim section (18) corresponds to the root circle diameter of the tooth portion (6) of the gear ring (4), and the edge section (15) of each injection-cast section (7) pointing radially outward relative to the central longitudinal axis (5) is at least partially or completely arranged between the inner circumference of the rim section (18) and the root circle diameter, in particular, the edge section (15) protrudes radially outward relative to the central longitudinal axis (5) beyond the root circle diameter into the area of ​​the tooth portion (6), preferably into the area of ​​the tooth root of the tooth portion (6).

7. The gear according to claim 6, characterized in that The edge sections (15) of each injection-cast section (7) are constructed in an arc shape, wherein the edge sections (15) of all injection-cast sections (7) are arranged on a common circle and concentrically with the central longitudinal axis (5), and in particular, the thickness of each injection-cast section (7) at least partially decreases in the direction of the edge section (15) and / or in the region of the edge section (15).

8. The gear according to any one of claims 6 or 7, characterized in that: The edge section (15) of each injection-molded section (7) has a streamlined profile (20), which has at least one chamfered portion and / or at least one rounded edge (21, 22). In particular, the streamlined profile (20) has a first rounded edge (21) with a first radius, wherein the first radius is bent convexly outwardly. In particular, the streamlined profile (20) has a second rounded edge (22) with a second radius, wherein the second radius is bent concavely inwardly and the second rounded edge (22) is constructed between the rim section (18) and the first rounded edge (21).

9. A gear according to any one of the preceding claims, characterised in that The outer part (3) has three injection-molded segments (7) or four injection-molded segments, wherein, in the case of three injection-molded segments (7), the injection-molded segments are arranged at an angle of 120° to one another around the central longitudinal axis (5), and in the case of four injection-molded segments, the injection-molded segments are arranged at an angle of 90° to one another around the central longitudinal axis (5).

10. A steering device for a vehicle, comprising a gear wheel (1, 27, 29, 35) according to any one of the preceding claims, wherein: The toothing (6) of the toothed ring (4) is designed as a helical toothing which cooperates with at least one worm wheel or at least one worm shaft.

11. Method for producing a gear wheel (1, 27, 29, 35) according to any one of claims 1 to 9, wherein: The inner part (2) is inserted into an injection mold, and the outer part (3) is injection molded with the aid of a hot runner distributor (23), wherein the hot runner distributor (23) has a plurality of outlet locations (24) for the plastic forming the outer part (3), the number of the outlet locations depending on the number of injection molding sections (7) to be formed of the outer part (3), and the outlet locations (24) are directed toward the side surface (8) of the inner part (2).

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