JP6412383B2 - Welding structure of differential for vehicles - Google Patents

Description

  The present invention relates to a welding structure for a differential for a vehicle.

  A vehicle differential device includes a differential case (hereinafter referred to as a differential case) in which a differential gear mechanism is incorporated, and a ring gear welded to the differential case. The differential gear mechanism incorporated in the differential case is disposed opposite to the differential case in a direction perpendicular to the side gear and a pair of side gears arranged coaxially and opposed to the central axis of the differential case. Each has a pair of pinions that mesh with the side gears. The side gear and the pinion are rotatably supported in the differential case. A differential device incorporating a differential gear mechanism is used as a final reduction gear, a transmission, a transfer, or the like.

  As described in Japanese Patent Application Laid-Open No. 2004-260, a differential gear of a type in which a ring gear is welded to a differential case is fitted to a differential case provided with a fitting surface coaxial with the central axis of the differential case, and the fitting surface. Some have a ring gear provided with a fitting hole. In this case, the differential case and the ring gear are welded at the fitting surface and the fitting hole.

  As described in Patent Document 2, another type of differential device has a differential case provided with a press-fitting surface coaxial with the central axis, and a ring gear provided with a press-fitting hole that is press-fitted into the press-fitting surface. There is a thing of structure. In this type of differential device, the differential case and the ring gear at the portion of the case-side abutting portion provided in the differential case at right angles to the press-fitting surface and the gear-side abutting portion provided in the ring gear Are welded.

  In any type, the ring gear is welded to the differential case by a laser beam, an electron beam, or the like, and a welded portion that is melted by the laser beam or the like, that is, a bead portion, and a heat-affected portion that is affected by the heat of the welded portion. It is formed. When the ring gear is welded to the differential case, the welded portion is formed such that the inner end of the welded portion is connected to the differential case and the ring gear via a sharp edge.

  As described in Patent Document 3, the welding structure in which the ring gear and the hollow shaft member are welded includes an end surface of the ring gear perpendicular to the press-fitting hole of the ring gear, and a flange provided on the shaft member. There is something that welds. Furthermore, Patent Document 4 discloses a power transmission gear in which a ring-shaped large gear and a small gear are welded.

Japanese Patent No. 5293840 Japanese Patent No. 5206656 JP 2012-82910 A JP-A-61-62663

  As in the differential devices described in Patent Documents 1 and 2, when an edge is formed at the weld boundary between the inner end of the welded portion and the base material at the weld end, the edge portion becomes a stress concentration portion during power transmission. It becomes. Thus, when an edge is present at the boundary between the welded portion and the base material, the edge portion becomes a stress concentration portion, the strength of the welded portion tends to be weaker than the base material, and when a welding defect occurs, It becomes impossible to ensure the weld boundary portion at a predetermined strength. For this reason, since there is a concern about the destruction of the boundary portion, it is necessary to enlarge the welding region in order to increase the durability of the differential.

  The ring gear of Patent Document 3 is provided with a protective surface that protrudes from the weld surface in order to prevent damage to the weld surface of the ring gear, but an edge is provided at the weld boundary between the weld and the base material. It is inevitable that this part becomes a stress concentration part. Moreover, although the circular arc surface is formed in the internal peripheral surface of the large gear of patent document 4, and the outer peripheral surface of a small gear, it is inevitable that each circular arc surface becomes a stress concentration part.

  An object of the present invention is to improve the durability of a differential device without increasing the welding area.

Differential of the present invention includes: a differential case that houses the differential gear mechanism, a welded structure of a vehicle differential and a ring gear which is welded to the differential case, the abutting portion of the case side to the differential case A step surface on the case side deviating from the abutment portion, and a step surface on the case side deviating from the abutment surface and the abutment portion on the gear side abutted against the abutment portion on the ring gear A stepped surface on the gear side that forms a cavity portion is provided between the inner end portion and the inner end portion by the both abutting portions by welding under a state in which the respective abutting portions are abutted against each other. forming a welded portion projecting, on at least one of the said differential case ring gear, and is positioned at a site recessed from the inner edge away from the inner end of the welded portion, during power transmission It provided with a force concentrated portion.

  According to the present invention, since the position away from the welded portion is the stress concentration portion, the strength of the differential device can be increased without generating a stress concentration portion in the welded portion, and the durability of the differential device is increased. Can be improved. Since the tolerance for the quality of the welding is relaxed, the manufacturing yield of the differential can be increased.

It is sectional drawing which shows the welding structure of the differential for vehicles which is one embodiment of this invention in the state which assembled | attached the ring gear to the differential case. It is an expanded sectional view of the A section in FIG. It is sectional drawing which shows the part similar to FIG. 2 after completion | finish of welding. It is sectional drawing which shows the part similar to FIG. 2 in the conventional differential device shown as a comparative example. It is sectional drawing which shows the part similar to FIG. 4 after the completion | finish of welding of the conventional differential gear. (A) is sectional drawing which shows the stress generation state in the differential apparatus shown in FIGS. 1-3 manufactured by welding, (B) is the stress generation in the conventional differential apparatus shown in FIG.4 and FIG.5. It is sectional drawing which shows a state. FIGS. 1 to 3 show the press-fitted state of the press-fit portion and the stress change at the edge portion of the differential device, (A) shows the edge portion on the differential case side, and (B) shows the edge on the gear side. Indicates the part. 4 and 5 show the press-fit state of the press-fit portion and the stress change at the edge portion of the differential device, (A) shows the edge portion on the differential case side, and (B) shows the gear side. The edge part of is shown. It is sectional drawing which shows the differential which is other embodiment in the state which assembled | attached the ring gear to the differential case. It is an expanded sectional view of the B section in FIG. [FIG. 11] It is sectional drawing which shows the part similar to FIG. 10 after completion | finish of welding.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  A differential case, that is, a differential device 10a shown in FIG. 1 has a differential case 11 that accommodates a differential gear mechanism, and a gear accommodating chamber 12 for accommodating a gear is formed in the differential case 11. This differential device 10a is applied to a final reduction gear. The differential gear mechanism incorporated in the differential case 11 includes a pair of side gears (not shown) arranged coaxially with the central axis O1 of the differential case 11 and opposed to each other, and in the direction perpendicular to the side gears. And a pair of pinions (not shown) arranged opposite to each other. The pinion is meshed with the side gear.

  Support holes 13 and 14 for supporting the drive shaft are formed in the differential case 11 so as to be coaxial with the central axis O1, and the side gear is attached to the drive shaft. Support holes 15 and 16 are provided in the differential case 11 so as to be coaxial with the radial axis O2 perpendicular to the central axis O1, and a pinion is attached to the support shaft attached to the support holes 15 and 16.

  A press-fit surface 17 is provided coaxially with the central axis O1 on the outer peripheral surface on one end side in the direction along the central axis O1 of the differential case 11. Further, the differential case 11 is provided with a flange 18 positioned closer to one end of the differential case 11 than the support holes 15 and 16, and a case-side abutting portion 19 is provided on the radially outer side of the flange 18. It has been. The abutting portion 19 is perpendicular to the press-fit surface 17.

  A ring gear 21 that is assembled to the differential case 11 and constitutes the differential 10a together with the differential case 11 is a curved bevel gear, and has an annular base portion 21a and a tooth portion 21b. A press-fitting hole 22 that is press-fitted into the press-fitting surface 17 is provided in the base portion 21 a of the ring gear 21, and the ring gear 21 is press-fitted into the differential case 11. The base 21 a of the ring gear 21 is provided with a gear-side abutting portion 23 that abuts against the abutting portion 19 of the flange 18. The abutting portion 23 is perpendicular to the press-fit hole 22.

  The differential case 11 is manufactured into a shape shown in FIG. 1 using cast iron by a casting process, a machining process such as a cutting process and a grinding process. On the other hand, the ring gear 21 is manufactured in a shape shown in FIG. 1 by gear cutting or heat treatment using carburized steel. The ring gear 21 meshes with a small gear (not shown). The differential device 10a is covered with a cover (not shown) and mounted on the vehicle.

  When the ring gear 21 is welded to the differential case 11, as shown in FIGS. 1 and 2, the press-fitting hole 22 of the ring gear 21 is press-fitted into the press-fitting surface 17 of the differential case 11, and the abutment portion 23 on the gear side is pushed on the case side. It is abutted against the contact part 19. As shown in FIG. 2, the differential case 11 has an inclined groove surface 24 formed on the radially outer portion of the abutting portion 19, and the radially outer side of the abutting portion 23 facing the groove surface 24. A groove surface 25 is formed in the part. The radially inner portions of the abutting portions 19 and 23 are abutting surfaces 26 and 27 that abut against each other.

  The differential case 11 is provided with a step surface 28 that is shifted to the radial axis O2 side with respect to the contact surface 26, and the ring gear 21 is provided with a step surface 29 that is shifted to the tooth portion 21b side with respect to the contact surface 27. Yes. When the ring gear 21 is assembled to the differential case 11, as shown in FIG. 2, a cavity 30 is formed by both step surfaces 28 and 29 between the differential case 11 and the ring gear 21.

  As shown in FIG. 2, when welding the differential case 11 and the ring gear 21 with both the abutting portions 19 and 23 being abutted, the laser is supplied while supplying filler metal to the groove portion. High energy is applied to the abutting portions 19 and 23 and the filler metal by the beam. As a result, as shown in FIG. 3, the abutting portions 19 and 23 are formed with a bead portion, that is, a welded portion 31 that is cooled after the metal is melted.

  FIG. 3 shows a welded portion 31 formed on the butting portions 19 and 23 by welding. By welding, the welding tip portion, that is, the inner end 32 of the welded portion 31 protrudes toward the cavity portion 30. The differential case 11 is provided with a flat surface 33 that is substantially perpendicular to the step surface 28 so as to be continuous with the inner end 32, and an arcuate surface 34 is provided between the flat surface 33 and the step surface 28. ing. On the other hand, the ring gear 21 is provided with a flat surface 35 substantially perpendicular to the step surface 29 so as to be continuous with the inner end 32, and stress concentration is provided between the flat surface 35 and the step surface 29. A concave groove 36 as a part is provided. Thus, since the groove 36 as the stress concentration portion is provided at a position away from the inner end 32 of the welded portion 31, when power is transmitted by the differential gear mechanism, Due to the load applied to the ring gear 21, the portion of the concave groove 36 becomes a stress concentration portion.

  As shown in FIG. 3, a heat affected zone 37 is formed by welding between the welded portion 31 and the differential case 11 that is the base material, and between the welded portion 31 and the ring gear 21 that is the base material. In the heat affected zone 37, the flat surfaces 33 and 35 are inward ends. Since the recessed groove 36 is provided at a position farther from the welded portion 31 than the flat surface 35, no stress concentration portion is generated in the welded portion 31 and the heat affected zone 37, and the portion of the recessed groove 36 is stress concentrated. Part. Since the arc surface 34 is also provided at a position away from the welded part 31 and the heat affected part 37, no stress concentration part occurs in the welded part 31 and the heat affected part 37.

  If a stress concentration part is provided in the welded part 31 or the heat affected part 37, depending on the welding state, the weld strength at these parts may be shifted from the design value. If there is a concern about the presence of this, it is necessary to enlarge the area of the welded portion 31 to reduce the stress value generated in the stress concentration portion. On the other hand, if the concave groove 36 is provided as a stress concentrating portion in the portion of the base material away from the welded portion 31 and the heat affected zone 37, the breaking strength of the ring gear 21 can be obtained based on the strength of the base material. The differential case 11 and the ring gear 21 can be set to an optimum strength that does not cause stress fracture. Moreover, if the concave groove 36 is provided as a stress concentration portion, the residual tensile stress due to the solidification shrinkage of the welded portion 31 can be reduced.

  As shown in FIGS. 1 to 3, in the differential device 10 a in which the ring gear 21 is press-fitted into the differential case 11, the influence of the stress applied to the welded portion due to the press-fitted state can be considered. If the stress concentration part is provided at a position away from the influence part 37, the influence of the press-fit state can be reduced.

  As described above, the concave groove 36 is provided in the ring gear 21, but the arc surface 34 of the differential case 11 may be a concave groove, and the concave groove 36 may be an arc surface, and at least one of the differential case 11 and the ring gear 21 may be provided. A concave groove 36 is provided as a stress concentration portion. However, as shown in FIGS. 1 to 3, when the concave groove 36 is provided between the welded portion and the press-fitting portion, the differential device is caused by a traveling load in both acceleration traveling and deceleration traveling. The stress generated in 10 a is concentrated in the concave groove 36, and the concave groove 36 as a stress concentration portion functions as a stress relief portion that prevents excessive stress from being applied to the welded portion 31 and the heat affected zone 37. Thereby, stress concentration on the welded part 31 and the heat affected part 37 can be avoided more reliably. The stress concentrating portion is not limited to the concave groove 36, and may be a right-angle surface in which the flat surface 35 is connected to the step surface 29 at a right angle. Further, the stress concentration portion provided between the welded portion and the press-fit portion may be provided on the step surface 29.

  FIG. 4 is a cross-sectional view showing a portion similar to FIG. 2 in a conventional differential shown as a comparative example, and FIG. 5 is a cross-sectional view showing a portion similar to FIG. 4 after welding of the conventional differential. is there. In these drawings, portions corresponding to the members shown in FIGS. 1 to 3 are denoted by the same reference numerals.

  Conventionally, as shown in FIG. 4, the contact surface 26 and the step surface 28 are connected by an arc surface, and the contact surface 27 and the step surface 29 are connected by an arc surface. 5, since the inner end 32 of the welded portion 31 protrudes toward the cavity portion 30, an edge portion 38 is generated between the inner end 32 of the welded portion 31 and the step surface 28. An edge portion 39 is generated between the inner end 32 and the step surface 29. The respective edge portions 38 and 39 become stress concentration portions during power transmission. The portions corresponding to the edge portions 38 and 39 are boundary portions between the welded portion 31 and the outer portion thereof. When excessive stress is applied to the welded portion 31, stress breakage easily occurs from that portion.

  6A is a cross-sectional view showing a stress generation state in the differential shown in FIGS. 1 to 3 manufactured by welding, and FIG. 6B is a conventional differential shown in FIGS. 4 and 5. It is sectional drawing which shows the stress generation | occurrence | production state in.

  As shown in FIGS. 1 to 3, when the concave groove 36 is provided at a position away from the welded portion 31 and the heat-affected zone 37, the portion facing the concave groove 36 has the highest stress under the power transmission state. It becomes area | region 40a, ie, a stress concentration part. This region 40 a is separated from the welded portion 31 and the heat affected zone 37, and is also separated from the edge portion 39 of the inner end 32. The regions indicated by reference numerals 40b to 40f indicate the stress state generated in the differential device, and indicate that the generated stress decreases toward the regions 40b to 40f.

  On the other hand, in the conventional differential device, as shown in FIG. 6B, the portion facing the edge portion 39 is a region 40a having the highest stress. Thus, if the edge part 39 becomes a stress concentration part, the possibility that the edge part 39 will break depending on the welding situation increases.

  FIG. 7 shows the press-fitting state of the press-fitting portion and the stress change at the edge portions 38 and 39 of the differential device shown in FIGS. FIG. 7A shows a stress change in the edge portion 38 on the differential case side, and FIG. 7B shows a stress change in the edge portion 39 on the gear side. On the other hand, FIG. 8 shows the press-fitted state of the press-fitting portion and the stress change at the edge portions 38 and 39 of the differential device in the conventional differential device shown in FIG. 4 and FIG. 8A shows a stress change in the edge portion 38 on the differential case side, and FIG. 8B shows a stress change in the edge portion 39 on the gear side.

  In these drawings, a solid line indicates a case where the pressure input of the press-fitting portion is maximized, and a broken line indicates a case where the pressure input is zero. When a pressure input is applied to the press-fit portion, a fastening stress is generated in the press-fit portion. When the pressure input is zero, no fastening force is generated. In the case of standard pressure input, it is halfway between the solid line and the broken line. In the figure, “+” stress indicates compressive stress, and “−” stress indicates tensile stress. “FWD” indicates the stress value when the vehicle is traveling with the engine power transmitted from the differential 10a to the drive wheel, and “REV” is from the drive wheel side during deceleration traveling or coast traveling. The stress value when a load is applied to the differential device 10a side is shown. The ring gear 21 is a bevel gear, and the small gear meshes with the ring gear 21. Therefore, when the ring gear 21 rotates, the toothed surface of the small gear and the tooth surface of the ring gear 21 are in contact with each other on the inner diameter side and the outer diameter side. The stress generated in the edge portions 38 and 39 is also different at the contact portion between the ring gear 21 and the small gear.

  When comparing the differential of the present invention shown in FIG. 7A with the conventional differential shown in FIG. 8A, the pressure input is zero when the pressure input is maximized as shown by the solid line. In any case, when the concave groove 36 is formed at a position away from the heat affected zone 37, the stress at the edge portion 38 on the case side is reduced.

  Further, when the differential device of the present invention shown in FIG. 7B is compared with the conventional differential device shown in FIG. 8B, the gear side of the conventional differential device when the pressure input is zero is shown. The amplitude of the stress change becomes large. On the other hand, when the concave groove 36 is formed at a position away from the heat affected zone 37, as shown in FIG. 7B, the amplitude of the stress change becomes small even when the pressure input is zero. Further, when the pressure input is maximized, in the conventional differential device, as shown in FIG. 8 (B), the stress direction changes into tensile stress and compressive stress with the rotation of the ring gear. When 36 is provided, the direction of stress does not change.

  In this way, when the stress concentration portion is formed by the concave groove 36 and the stress concentration portion is separated from the welded portion, the stress generated in the edge portions 38 and 39 can be relaxed under all conditions. In particular, when no pressure input is applied, the stress at the edge portions 38 and 39 can be relaxed with certainty.

  In the above-described differential device 10a, the stress of the welded portion is relieved by providing the stress concentration portion at a position away from the welded portion, so that the strength of the differential device 10b can be increased without increasing the thickness thereof. Can be enhanced. Thereby, the durability of the differential device can be improved. Moreover, since the influence of the pressure input of the press-fit portion, that is, the fastening force can be reduced, the tolerance and the surface roughness of the press-fit surface 17 and the press-fit hole 22 can be relaxed. Furthermore, since the tolerance of quality of the welded state can be relaxed, the manufacturing yield can be increased.

  FIG. 9 is a cross-sectional view showing a differential device according to another embodiment, and shows a state where a ring gear is assembled to a differential case. FIG. 10 is an enlarged cross-sectional view of part B in FIG. 9, and FIG. 11 is a cross-sectional view showing the same part as in FIG. 10 after the end of welding. In these drawings, members that are the same as those described above are given the same reference numerals.

  In the differential device 10b, the differential case 11 is provided with a fitting surface 51 coaxially with the central axis O1 of the differential case 11, and the ring gear 21 is provided with a fitting hole 52 to be fitted to the fitting surface 51. . When the ring gear 21 is welded to the differential case 11, the fitting hole 52 of the ring gear 21 is fitted, that is, fitted to the fitting surface 51 of the differential case 11. At the time of the fitting, no stress is generated in the differential case 11 and the ring gear 21 because no tightening force is generated as in the case of press-fitting as described above.

  When the tooth portion 21b side of the ring gear 21 is the tip portion of the ring gear 21, a first gear side abutting portion 23a is provided on the distal end portion side, and a second gear side abutting portion 23b is provided on the base end portion side. Is provided. The differential case 11 is provided with a first case-side abutting portion 19a corresponding to the first gear-side abutting portion 23a, and the differential case 11 is provided corresponding to the second gear-side abutting portion 23b. Is provided with an abutting portion 19b on the second case side. A step surface 28 is provided between both case-side abutting portions 19a and 19b, and a step surface 29 is provided between both ring-side abutting portions 23a and 23b. As a result, when the ring gear 21 is assembled to the differential case 11, as shown in FIG. 10, a hollow portion 30 is formed in the central portion in the axial direction between the fitting surface 51 and the fitting hole 52.

  In this manner, the ring gear 21 is welded to the differential case 11 at both axial ends in the direction along the central axis O1 of the base 21a of the ring gear 21. Each abutting portion is provided with a groove surface and a contact surface as in the case described above. On the first abutting portion 23 a side of the ring gear 21, a concave groove 36 a is formed between the flat surface 35 and the step surface 29. On the other hand, on the second abutting portion 23b side of the ring gear 21, an arc surface 34a is formed between the flat surface 35 and the step surface.

  On the other hand, an arc surface 34 b is formed between the flat surface 33 and the step surface 28 on the first abutting portion 19 a side of the differential case 11. On the other hand, a concave groove 36 b is formed between the flat surface 33 and the step surface 28 on the second abutting portion 19 b side of the differential case 11.

  Therefore, as shown in FIG. 11, when the butting portion 23a and the butting portion 19a are welded, the first welded portion 31a is formed at these portions. Similarly, when the butting portion 23b and the butting portion 19b are welded, the second welded portion 31b is formed at these portions. A heat affected zone 37 is formed between each welded portion 31a, 31b and the base material. The concave groove 36a is provided at a position away from the welded portion 31a and the heat-affected portion 37 outside thereof, and the concave groove 36a becomes a stress concentration portion. Similarly, the concave groove 36b is provided at a position away from the welded portion 31b and the heat-affected portion 37 outside thereof, and the concave groove 36b becomes a stress concentration portion. If both the concave grooves 36a and 36b are provided in the diagonal direction via the hollow portion 30, it is possible to prevent the stress generated by the load applied to the ring gear 21 from concentrating on the welded portion.

  In the differential device 10b shown in FIG. 9, as in the differential device 10a, the durability can be improved by improving the strength of the differential device and the manufacturing yield can be increased.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, the ring gear 21 described above is a bevel gear, but a spur gear may be used as a ring gear.

10a, 10b Differential device 11 Differential case 18 Flange 19 Abutting portion 19a First abutting portion 19b Second abutting portion 21 Ring gear 22 Press-fit hole 23 Abutting portion 23a First abutting portion 23b Second abutting Portions 26 and 27 Contact surfaces 28 and 29 Stepped surface 30 Cavity portion 31 Welded portion 31a First welded portion 31b Second welded portion 32 Inner end 33 Flat surface 34 Arc surface 35 Flat surface 36 Concave groove 37 Heat affected zone 38, 39 Edge part 51 Fitting surface 52 Fitting hole

Claims (7)

A differential structure for a vehicle has a differential case that houses a differential gear mechanism, and a ring gear that is welded to the differential case.
The differential case is provided with a case-side abutting portion and a case-side step surface shifted from the abutting portion, while the ring gear abuts the gear-side abutting portion and the abutting surface against the abutting portion. Providing a stepped surface on the gear side that forms a cavity with the stepped surface on the case side that is displaced more than ,
Under the state in which the respective abutting portions are abutted , a welded portion in which an inner end projects into the hollow portion by both the abutting portions is formed by welding,
At least one of the differential case and the ring gear is located at a site that is separated from the inner end of the welded portion and is retracted from the inner end, and is provided with a stress concentration portion during power transmission .
Welding structure for vehicle differential.   2. The welding structure for a vehicle differential according to claim 1, wherein the stress concentration portion is provided away from the heat affected zone.   3. The welding structure for a vehicle differential according to claim 1, wherein the stress concentration portion is a concave groove. In the welding structure of the differential for vehicles according to any one of claims 1 to 3,
The differential case is provided with a press-fitting surface coaxial with the central axis of the differential case,
The ring gear is provided with a press-fitting hole that is press-fitted into the press-fitting surface,
Provide a case-side butting portion on the flange provided in the differential case at a right angle to the press-fit surface,
A welding structure for a differential for a vehicle, wherein an abutting portion on the gear side is provided at an end portion of the ring gear.   5. The welding structure for a vehicle differential according to claim 4, wherein the stress concentration portion is provided on the ring gear. In the welding structure of the differential for vehicles according to any one of claims 1 to 3,
The differential case is provided with a fitting surface coaxially with the central axis of the differential case,
Provide a fitting hole to be fitted to the fitting surface in the ring gear,
A first gear side abutting portion is provided on the distal end side of the fitting hole, and a second gear side abutting portion is provided on the base end side;
A first case-side abutting portion that forms a first welded portion together with the first gear-side abutting portion, and a second welded portion that forms a second welded portion together with the second gear-side abutting portion. A case-side butting portion is provided on the fitting surface,
A welding structure for a differential for a vehicle, wherein a hollow portion is provided in an axially central portion of the fitting surface and the fitting hole. The welding structure for a vehicle differential according to claim 6,
The differential gear case is provided with a first stress concentration portion on the ring gear positioned at a position away from the inner end of the first welded portion, and positioned at a position away from the inner end of the second welded portion. A welding structure for a vehicle differential device, wherein a second stress concentration portion is provided on the vehicle.

Images