Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
  • F15B15/20—Other details, e.g. assembly with regulating devices
  • F15B15/22—Other details, e.g. assembly with regulating devices for accelerating or decelerating the stroke
  • F15B15/224—Other details, e.g. assembly with regulating devices for accelerating or decelerating the stroke having a piston which closes off fluid outlets in the cylinder bore by its own movement
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
  • F15B15/08—Characterised by the construction of the motor unit
  • F15B15/14—Characterised by the construction of the motor unit of the straight-cylinder type
  • F15B15/1423—Component parts; Constructional details
  • F15B15/1447—Pistons; Piston to piston rod assemblies
  • F15B15/1452—Piston sealings
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16J—PISTONS; CYLINDERS; SEALINGS
  • F16J9/00—Piston-rings, e.g. non-metallic piston-rings, seats therefor; Ring sealings of similar construction
  • F16J9/08—Piston-rings, e.g. non-metallic piston-rings, seats therefor; Ring sealings of similar construction with expansion obtained by pressure of the medium
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16J—PISTONS; CYLINDERS; SEALINGS
  • F16J9/00—Piston-rings, e.g. non-metallic piston-rings, seats therefor; Ring sealings of similar construction
  • F16J9/12—Details
  • F16J9/14—Joint-closures

Definitions

• the invention relates to a working cylinder with end position damping and a damping piston ring.
• damping solutions are known in the prior art. These solutions are aimed at constantly or progressively decelerating the movement of a piston within a hydraulic working cylinder in a defined area.
• the deceleration of the movement can be provided by throttling the outflow of the hydraulic fluid by means of a damping element. This damping element reduces the cross-section through which the hydraulic fluid can drain.
• the working cylinder with end position damping has a cylinder and a piston unit.
• the first closure part is arranged on the first cylinder tube end and the second closure part on the second cylinder tube end of the cylinder tube.
• the arrangement of the two closure parts is designed in such a way that they are connected to the respective ends of the cylinder tube in a pressure-tight manner.
• the two closure parts are preferably each welded to the cylinder tube along the circumferential common contact surface. Other connections, such as screwing, are also possible.
• the cylinder tube and the closure parts form a cylinder interior.
• the cylinder interior is to be understood as meaning the interior of the cylinder formed by the closure parts and the cylinder tube, in which the pressure medium is located when used as intended.
• the piston is arranged in the cylinder interior.
• the cylinder has a damping zone in at least one end area. The damping zone is the area of the cylinder interior in which damping occurs when the piston unit runs in.
• Damping is understood to mean a force effect that delays the movement of the piston unit.
• the damping zone is located on at least one end area of the cylinder tube and encompasses the part of the cylinder interior between a pressure medium connection and an axial delimitation by the closure part arranged on this end area.
• the cylinder has a laterally arranged pressure medium connection, the pressure medium connection being assigned to the damping zone and being spaced axially from the axial boundary of the cylinder interior.
• the damping zone extends between the pressure medium connection and the axial limit.
• the axial limitation positively blocks further movement of the piston unit and thus defines the maximum movement path of the piston unit axially on one side.
• the end position of the piston unit during operation can also be before the axial limit is reached.
• the piston unit has a piston and a piston ring.
• the piston unit is preferably composed of a piston rod and the piston.
• the piston unit can be designed differently.
• the piston rod can be guided completely through or only partially into the piston.
• the piston unit can be monolithic and then only have a piston rod section and a piston section. According to the invention, the piston unit slides through the first closure part and forms at least one working space in the cylinder interior.
• the first closure part is designed to accommodate the piston unit in a sliding manner and has sealing and guide elements for this purpose.
• the end position damped piston ring according to the invention is characterized in particular by the special design of the piston ring.
• the piston ring is an essentially rotationally symmetrical part that has an interruption on the circumference and thus has a ring body and a ring joint.
• the radial annular surface is designed as a sliding contact surface that can be displaced axially with respect to a cylindrical inner lateral surface of a cylinder.
• the radial annular surface is in physical contact with the inner wall of the cylinder in a manner known per se, the physical contact occurring as a sliding contact when the piston moves relative to the cylinder.
• the ring body ends are arranged opposite one another at the ring joint. They form the ring joint.
• the first end of the ring body and the second end of the ring body are designed to be complementary to one another.
• the first end of the ring body has a projection section and the second end of the ring body has a base section.
• the first annulus end has the cantilever portion with a cantilever contour cross section.
• the projection contour cross-section is determined by the shape of the projection and designates the contour of the projection section in a radial sectional plane parallel to the main longitudinal axis.
• the projection contour is thus formed by a physical portion of the piston ring.
• a projection section separating surface of the projection section and a base section separating surface of the base section face each other in a planar and sealing contact and form a separating plane.
• the cantilever portion interface and the base portion interface are also hereinafter collectively referred to as the interface.
• the outside parting line and the inside parting line are also collectively referred to below as the parting lines.
• the interlocking ring body ends formed in this way have a very precise sealing geometry, which has a sealing overlap even with a variable circumferential expansion and the resulting variable annular gap.
• This also results from the fact that at least one dividing line, preferably both dividing lines, have a concentric radius of curvature.
• the piston ring can expand or contract in the circumferential direction at any time and the seal across the interface is maintained. Circumferential expansion or contraction may result from a wavy shape of the inner surface of the cylinder, or from temperature-related expansion or contraction, or from wear.
• the piston ring is advantageously able to compensate for these factors and at the same time maintain its particularly high degree of tightness.
• the projection portion can slide radially and circumferentially on the parting surface with the base portion at any time. This ensures wear compensation at all times, which leads to a permanent sealing function.
• the sealing piston ring can be formed with two mutually parallel axial annular surfaces lying in its main plane in the outer contour, see above that the annular groove of the piston for accommodating the piston ring can be designed in a structurally simple manner with parallel axial walls.
• a particular advantage of the sealing piston ring is that it can be provided with an essentially rectangular geometry of its outer cross section, so that the ring groove can be formed in the piston in a particularly simple manner.
• the working cylinder with end position damping according to the invention has at least one axial overflow channel.
• This is alternatively or cumulatively designed as a cylinder tube inner lateral surface axial groove or as a piston ring outer lateral surface axial groove.
• the cylinder tube inner lateral surface axial groove is also abbreviated as the cylinder pipe axial groove
• the piston ring outer lateral surface axial groove is also abbreviated as the piston ring axial groove and both together are also abbreviated as the axial grooves.
• the cylinder barrel axial groove is arranged in the damping zone in axial terms.
• the piston ring axial groove is arranged in the radial ring surface. In both alternative configurations, the axial groove is designed to allow a pressure medium overflow through the cross section of the axial groove.
• the piston unit is designed to travel over the pressure medium connection with the piston ring axially during an entry movement into the damping zone and to enclose a damping pressure medium volume in a damping zone space in the damping zone.
• the damping zone designates the part of the cylinder interior that is delimited by the piston unit, the closure part and the cylinder tube after the pressure medium connection has been passed over by the piston ring. As the axial movement of the piston unit progresses in the direction of the axial end position, the damping zone space becomes smaller.
• the part of the pressure medium that is enclosed in the damping zone space and flows out of it is referred to as the damping pressure medium volume.
• the piston unit including the piston ring according to the invention is designed to form a damping operating state of the working cylinder during a retraction movement within the damping zone.
• the damping pressure medium volume is enclosed by the piston unit, as a result of which the pressure in the damping zone space increases compared to the pressure at the pressure medium connection.
• the damping pressure medium volume there is an overpressure of the damping pressure medium volume compared to the operating pressure in the damping operating state.
• the overpressure of the damping pressure medium volume is also referred to below as the damping overpressure.
• the operating pressure is understood to mean the pressure of the pressure medium present at the pressure medium connection, which pressure corresponds to the pressure in the rest of the working space.
• Linear damping, progressive damping and also another damping characteristic can advantageously be provided.
• the axial overflow channel is formed by a piston ring axial groove
• precise linear damping can be achieved in particular.
• a section-stepped or other damping characteristic can be made possible by the axial overflow channel being formed by a cylinder tube axial groove. If a cylindrical tube axial groove is formed with a cross section that is the same over its longitudinal extent, there is linear damping. By reducing the cross section over the longitudinal extent in the direction of the end position, progressive damping can be set in a simple manner.
• degressive damping can also be set in a simple manner, in that the cross section widens in the direction of the end position.
• a cross section of the axial overflow channel that differs along the longitudinal extent can also be solved by arranging a plurality of cylinder tube axial grooves of different lengths, which are therefore only effective in sections.
• a stepwise increasing or stepwise decreasing damping can be adjusted.
• cylinder tube axial grooves which extend axially only over a partial section of the damping zone can thus simultaneously provide stroke section damping with little effort.
• the end position damping can be provided both in only one end position and in both end positions.
• the solution can be used in different cylinder types, such as in particular differential working cylinders, synchronous cylinders, pull cylinders or plunger cylinders.
• the elastic piston ring which is tensioned against the inner wall of the cylinder, can advantageously also compensate for deviations in the cylinder tube caused by production and thus enable high precision damping.
• both the outer parting line and the inner parting line have a radius of curvature that is concentric with the annular body.
• both dividing lines thus have a radius of curvature that is concentric with one another and is therefore the same.
• the parting surfaces of the ring body ends are designed as truncated cone surfaces.
• the projection section separating surface designed as a truncated cone surface and the base section separating surface embodied as a truncated cone surface are opposite, the projection section separating surface being a concave inner truncated cone surface and the base section separating surface being a convex outer truncated cone surface.
• the two opposing truncated cone surfaces also have the same geometry and can therefore be moved both lengthwise and crosswise to each other, thus always ensuring its particularly high level of tightness.
• the separating surfaces are designed as wire eroding surfaces.
• the piston ring has at least one weakened recess.
• the spring force-related contact pressure forces on an inner lateral surface of a cylinder are distributed uniformly over the circumference and the free mobility and self-adjusting effect between the projection section and the base section are supported.
• the advantageous contact pressure forces caused by the excess damping pressure of the pressure medium remain unaffected.
• a piston ring with the same initial geometry and the same material can thus be particularly advantageously adapted to the respective application requirements in a simple manner, with the contact pressure caused by the spring force.
• the weakening recesses can act like elastic joints that segment the piston ring along its circumference, so that the segments formed in this way rest more precisely against the inner wall of the cylinder tube.
• the first axial annular surface of the piston ring has an inclination opposite to the parting surfaces.
• both the inclined annular surface and the parting plane each have an inclination relative to a main plane have plane of the piston ring, with this inclination in each case to a different side of the main plan plane.
• the axial annular groove surface of the annular groove of the piston is correspondingly also inclined in the same way.
• the inclined first axial annular surface of the piston ring is designed as a contact surface for the inclined axial annular groove surface of the annular groove, so that both inclined annular surfaces bear against one another over a wide area.
• the design as an inclined axial ring surface promotes the dynamic expansion of the piston ring. This takes place via the obliquely acting force of the inclined axial annular surface.
• the axially acting force resulting from the pressure load of the pressure medium, leads to an obliquely acting contact pressure force on the inclined and thus oblique ring surface of the ring groove of the piston.
• the wedge effect on the inclined ring surface leads to a radial expansion of the piston ring and to a force acting on the surface pressure between the radial ring surface and the inner surface of the cylinder. This in turn ensures an increased sealing effect in the damping operating state.
• the axial overflow channel is designed as an axial groove on the inner surface of the cylinder tube and the axial groove on the inner surface of the cylinder tube has a cross section that tapers in the direction of the end position.
• the design of the axial overflow channel as an axial groove on the inner surface of the cylinder tube, shortened to an axial groove on the cylinder tube, with a cross section that tapers in the direction of the end position, means that the outflow cross section available to the pressure medium is dependent on the position of the piston ring in the damping zone and thus on the axial position of the piston unit. Due to the narrowing of the cross-section, the outflow cross-section is reduced the further the piston unit performs its retraction movement towards the end position. The force counteracting the retraction movement increases continuously. Thus, there is a progressive damping. The simple and reliable feasibility of progressive damping is particularly advantageous.
• the cylinder has a further damping zone in a further end region axially opposite the end region.
• the cylinder has a further laterally arranged pressure medium connection, the further pressure medium connection being assigned to the further damping zone and being axially spaced from a further axial boundary of the cylinder interior opposite the axial boundary.
• the further pressure medium connection, the further damping zone and the further axial limitation basically correspond in function and design to the pressure medium connection, the damping zone and the axial limitation.
• the further damping zone and the further pressure medium connection are arranged in the spatial vicinity of the second closure part on the second end of the cylinder tube.
• the piston unit is designed to have a further damping operating state during a retraction movement within the further damping zone.
• the further damping operating state has the characteristics of the damping operating state in a corresponding manner.
• the damping piston ring according to the invention represents a further aspect of the invention.
• the damping piston ring is placed under protection as an independent machine component.
• the characteristics of the damping piston ring correspond to the characteristics of the piston ring as described as part of the end-of-stroke cushioned working cylinder according to the invention.
• the special tightness of the damping piston ring at its ring joint is essential.
• the damping piston ring also has at least one piston ring outer lateral surface axial groove on its radial annular surface, which connects the axial annular surfaces.
• piston ring outer lateral surface axial groove abbreviated to piston ring axial groove, an exactly definable overflow cross section is advantageously created between the two axial sides of the damping piston ring.
• a reliable precision damping piston ring for different damping devices and damping cylinders is created as a particular advantage, in which on the one hand a piston ring with a ring gap is required and on the other hand a particularly precise damping behavior is desired.
• This is advantageously made possible by precisely defining an overflow cross section. It is also advantageous that the cross section formed by the piston ring axial grooves is delimited in one section by the inner wall of the cylinder. Due to the relative axial movement of the damping piston ring in relation to the cylinder wall, any deposits of dirt in the axial groove of the piston ring are constantly discharged and functional impairments are counteracted in this way.
• An axial groove is understood to mean that an axial connection is created between the axial annular surfaces.
• the piston ring axial grooves can also be formed obliquely or spirally or with other modifications, for example to prevent unwanted run-in patterns on the cylinder inner wall.
• the invention is an exemplary embodiment based on Fig. 1 Sectional view of a working cylinder with end position damping as a differential cylinder with end position damping on both sides
• FIG. 2 Plan view of a piston ring
• Fig. 4 Detailed section of a piston ring at the ends of the ring body as an oblique view
• FIG. 1 shows an overall view of the end-of-travel damped working cylinder.
• This embodiment is a differential working cylinder with end position damping on both sides.
• the end position damping is arranged at the end position assigned to the second closure part 1.4. It is an end position cushioning on the piston head, which dampens the retraction movement.
• the further end position damping is arranged at the end position assigned to the first closure part 1.3. There it is an end position damping on the guide locking part, which dampens the extension movement.
• the piston 2.1 is guided in the cylinder tube 1.1 by means of a guide 2.4.
• the cross section is essentially rectangular.
• the view shows the outside of the piston ring 3.0 in the direction of the radial ring surface 3.3.
• the first axial annular surface 3.4 is located orthogonally thereto.
• the projection section 3.9 At the first ring body end 3.5 is the projection section 3.9. This has—against the viewing direction of FIG. 3—the projection section separating surface 3.15.
• Fig. 8 shows an embodiment of the piston ring 3.0 of the working cylinder with end position damping and at the same time an embodiment of the damping piston ring as such.
• the first axial annular surface 3.4 is inclined in this embodiment.
• the piston ring has a plurality of axial grooves 4.2 on the outer circumferential surface of the piston ring, distributed on its outer circumference, only two of which are provided with a reference symbol.

Landscapes

• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Pistons, Piston Rings, And Cylinders (AREA)
• Fluid-Damping Devices (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=73740153

Family Applications (1)

Country Status (6)

Families Citing this family (2)

Family Cites Families (11)

• 2020
  • 2020-10-19 DE DE112020007704.7T patent/DE112020007704A5/de active Pending
  • 2020-10-19 CN CN202080105617.3A patent/CN116324187A/zh active Pending
  • 2020-10-19 JP JP2023523569A patent/JP2023550887A/ja active Pending
  • 2020-10-19 WO PCT/DE2020/000248 patent/WO2022083811A1/de active Application Filing
  • 2020-10-19 EP EP20820320.8A patent/EP4229305A1/de active Pending
  • 2020-10-19 US US18/249,412 patent/US20230392617A1/en active Pending

Also Published As

Similar Documents

Legal Events