1. A shock absorberpneumatic spring strut comprising an essentially cylindrical housing, an air spring with a working space which is under internal pressure, an additional volume which can be connected to the working space via a closable flow duct, wherein the additional volume is enclosed by a hollow body which radially surrounds the housing and is formed from an outer cylinder and a concentrically arranged and connected inner cylinder.
2. The strut as claimed in claim 1, wherein the outer cylinder or the inner cylinder of the hollow body is formed by hydroforming or by a hot drawing-in process by means of rolling metallic pipe lengths.
3. The strut as claimed in claim 1, wherein the axial ends of the outer cylinder and of the inner cylinder are connected to one another frictionally or with an adhesive material in order to form the hollow body.
4. The strut as claimed in claim 1, wherein the hollow body is fastened to the housing of the strut with a form fit or press-fit.
5. The strut as claimed in claim 1, wherein the working space of the air spring surrounds the housing, and wherein the hollow body is arranged in the axial direction of the housing below the working space of the air spring.
6. The strut as claimed in claim 1, wherein the air spring has a flexible wall in the form of a rolling bellows and bounds the working space which is under internal pressure, the rolling bellows being fastened at one end thereof to the outer cylinder of the hollow body.
7. The strut as claimed in claim 1, wherein the outer cylinder of the hollow body forms a sliding surface, in particular running conically, for a rolling fold of the rolling bellows.
8. The strut as claimed in claim 1, wherein the flow duct is formed by an annular gap between the housing of the shock absorber and the inner cylinder of the hollow body.
9. The strut as claimed in claim 1, wherein a press fit is formed in a region below the flow duct between the housing of the shock absorber and the inner cylinder of the hollow body.
10. The strut as claimed in claim 1, wherein at least one spacer is arranged in the flow duct between the housing and the inner cylinder of the hollow body.
11. The strut as claimed in claim 10, wherein the spacer is of annular design and has air passage openings running in the axial direction.
12. The strut as claimed in claim 10, wherein a plurality of the spacers designed as ring segments are arranged in the flow duct between the housing and the inner cylinder of the hollow body.
13. The strut as claimed in claim 10, wherein the inner cylinder of the hollow body has at least one radially outwardly directed, groove-like wall recess in order to form at least one mount for the spacer.
14. The strut as claimed in claim 1, wherein at least two diametrically opposite, but preferably three or more bead-like, radially inwardly curved regions are formed on the inner cylinder of the hollow body in the region of the flow duct.
15. The strut as claimed in claim 1, wherein the inner cylinder of the hollow body has a valve seat for an overflow valve for closing the flow duct.
16. The strut as claimed in claim 15, wherein the inner cylinder of the hollow body has a radially outwardly directed curvature in order to form the valve seat.
17. The strut as claimed in claim 15, wherein the overflow valve has a tappet which reaches through the hollow body, in particular in the radial direction, and which is mounted in the outer cylinder of the hollow body.
18. The strut as claimed in claim 17, wherein the outer cylinder of the hollow body has, for the mounting of the overflow valve, and the tappet, a receiving opening surrounded by a radially inwardly directed wall section of the outer cylinder.
19. The strut as claimed in claim 1, wherein the inner cylinder of the hollow body has at least one radially outwardly directed, groove-like corrugation in order to form at least one holder for a circumferential seal.
20. The strut as claimed in claim 1, wherein the outer cylinder or the inner cylinder has a wall thickness of between 0.5 mm and 4.8 mm.
21. A hollow body for the enclosure of an additional volume of air for a shock absorberpneumatic spring strut of the type having an air spring leg, a damper arrangement including a shock absorber having an essentially cylindrical housing and an air spring with a working space which is under internal pressure. The hollow body comprising being connected to the working space via a closable flow duct, wherein a wall comprises an outer cylinder and an inner cylinder, which is connected to the outer wall and arranged concentrically therewith, the inner cylinder being adapted for surrounding the housing of the shock absorber of the strut arrangement.
22. The hollow body as claimed in claim 21, wherein the outer cylinder or the inner cylinder is formed by hydroforming or by a hot drawing-in process by means of rolling metallic pipe lengths.
23. The hollow body as claimed in claim 21, wherein the axial ends of the outer cylinder and of the inner cylinder are connected to one another frictionally or with an adhesive material joint.
24. The hollow body as claimed in claim 21, wherein the outer cylinder can be connected at one end to a rolling bellows of the air spring, the rolling bellows being formed by a flexible wall of the air spring.
25. The hollow body as claimed in claim 24, wherein the outer cylinder forms a sliding surface, in particular running conically, for a rolling fold of the rolling bellows.
26. The hollow body as claimed in claim 21, wherein the inner cylinder has at least one radially outwardly directed, groove-like wall recess in order to form at least one mount for one or more spacers arranged in the flow duct between the housing of the shock absorber and the inner cylinder.
27. The hollow body as claimed in claim 21, wherein at least two diametrically opposite, bead-like, radially inwardly curved regions are formed on the inner cylinder.
28. The hollow body as claimed in claim 27, wherein three or more bead-like, radially inwardly curved regions are formed on the inner cylinder in the region of the flow duct.
29. The hollow body as claimed in claim 21, wherein the inner cylinder has a valve seat for an overflow valve for closing the flow duct.
30. The hollow body as claimed in claim 21, wherein the inner cylinder has a radially outwardly directed curvature in order to form the valve seat.
31. The hollow body as claimed in claim 21, wherein the outer cylinder has, for the mounting of an overflow valve, in particular a tappet of an overflow valve, a receiving opening which is preferably surrounded by a radially inwardly directed wall section of the outer cylinder.
32. The hollow body as claimed in claim 21, wherein the inner cylinder has at least one radially outwardly directed, groove-like corrugation in order to form at least one holder for a circumferential seal.
33. The hollow body as claimed in claim 21, wherein the outer cylinder or the inner cylinder has a wall thickness of 0.5 mm and 4.8 mm.
34. The hollow body as claimed in claim 21, wherein the enclosed additional volume is part of the damper arrangement, in particular the air spring, the damper arrangement including a shock absorber having an essentially cylindrical housing and an air spring with a working space which is under internal pressure, and the additional volume which can be connected to the working space via the closable flow duct, the additional volume being enclosed by the hollow body surrounding the shock absorber.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An optical scanning device which separately scans a plurality of scan target surfaces in a first direction with light, the optical scanning device comprising:
a light source unit configured to emit a first light beam and a second light beam mutually different in polarization state;
an optical deflector configured to rotate around an axis parallel to a second direction perpendicular to the first direction, and deflect the first light beam and the second light beam emitted from the light source unit;
an imaging optical element provided on respective optical paths of the first light beam and the second light beam deflected by the optical deflector;
a polarization adjustment element provided on the optical paths of the first light beam and the second light beam transmitted through the imaging optical element, and configured to correct respective changes in polarization state of the first light beam and the second light beam occurring during the transmission of the first light beam and the second light beam through the imaging optical element; and
a polarization separation element provided on the optical paths of the first light beam and the second light beam emitted from the polarization adjustment element, and configured to separate the first light beam and the second light beam from each other.
2. The optical scanning device according to claim 1, wherein at least one of the first light beam and the second light beam satisfies a relationship |\u03b83(\u03a6N)\u2212\u03b82(\u03a6N)+\u03b81(\u03a6N)|>|\u03b83(\u03a6N)\u2212\u03b82(\u03a6N)+\u03b80(\u03a6N)|,
wherein \u03a6 represents an angle formed between a light beam incident on the polarization separation element and a plane parallel to the second direction and including a normal line of an incidence position of the light beam in the polarization separation element,
wherein \u03b80(\u03a6) represents an angle formed between the plane and a major axis direction of a polarized light of the light beam at the time of incidence of the light beam on the imaging optical element,
wherein \u03b81(\u03a6) represents an angle formed between the plane and the major axis direction of the polarized light of the light beam at the time of incidence of the light beam on the polarization adjustment element,
wherein \u03b82(\u03a6) represents an angle formed between the plane and the major axis direction of the polarized light of the light beam at the time of incidence of the light beam on the polarization separation element,
wherein \u03a6N represents an angle formed between the light beam incident on the polarization separation element and the plane, and corresponding to the maximum value of the difference between the angles \u03b80(\u03a6) and \u03b81(\u03a6), and
wherein \u03b83(\u03a6) represents, when a linearly polarized light having the same wavelength as the wavelength of the light beam is incident on the polarization separation element at the angle \u03a6N, an angle formed between the plane and a polarization direction of the linearly polarized light corresponding to a maximum extinction ratio.
3. The optical scanning device according to claim 1, wherein at least one of the first light beam and the second light beam satisfies a relationship |P0(\u03a6M)\u2212P1(\u03a6M)|>|P0(\u03a6M)\u2212P2(\u03a6M)|,
wherein \u03a6 represents an angle formed between a light beam incident on the polarization separation element and a plane parallel to the second direction and including a normal line of an incidence position of the light beam in the polarization separation element,
wherein P0(\u03a6) represents a degree of polarization at the time of incidence of the light beam on the imaging optical element,
wherein P1(\u03a6) represents a degree of polarization at the time of incidence of the light beam on the polarization adjustment element,
wherein P2(\u03a6) represents a degree of polarization at the time of incidence of the light beam on the polarization separation element, and
wherein \u03a6M represents an angle formed between the light beam incident on the polarization separation element and the plane, and corresponding to the maximum value of the difference between the degrees of polarization P0(\u03a6) and P1(\u03a6).
4. The optical scanning device according to claim 1, wherein the polarization separation element includes a polarization separation surface formed by a dielectric multilayer film.
5. The optical scanning device according to claim 1, wherein at least one of the first light beam and the second light beam satisfies a relationship |\u03b80(\u03a6N)\u2212\u03b81(\u03a6N)|>|\u03b80(\u03a6N)\u2212\u03b82(\u03a6N)|,
wherein \u03a6 represents an angle formed between a light beam incident on the polarization separation element and a plane parallel to the second direction and including a normal line of an incidence position of the light beam in the polarization separation element,
wherein \u03b80(\u03a6) represents an angle formed between the plane and a major axis direction of a polarized light of the light beam at the time of incidence of the light beam on the imaging optical element,
wherein \u03b81(\u03a6) represents an angle formed between the plane and the major axis direction of the polarized light of the light beam at the time of incidence of the light beam on the polarization adjustment element,
wherein \u03b82(\u03a6) represents an angle formed between the plane and the major axis direction of the polarized light of the light beam at the time of incidence of the light beam on the polarization separation element, and
wherein \u03a6N represents an angle formed between the light beam incident on the polarization separation element and the plane, and corresponding to the maximum value of the difference between the angles \u03b80(\u03a6) and \u03b81(\u03a6).
6. The optical scanning device according to claim 1, wherein the polarization separation element includes a polarization separation surface formed by a wire grid.
7. The optical scanning device according to claim 1, wherein the imaging optical element is made of resin.
8. The optical scanning device according to claim 1, wherein the polarization adjustment element includes a liquid crystal element including a nematic liquid crystal layer held between a pair of transparent plates via oriented films, and
wherein at least one of the oriented films has an orientation direction changed in accordance with the angle of incidence of light.
9. The optical scanning device according to claim 1, wherein the polarization adjustment element and the polarization separation element form a single unit.
10. An image forming apparatus comprising:
a plurality of image carriers each configured to carry an image; and
an optical scanning device according to claim 1, configured to scan the plurality of image carriers with light.