Scraper ring and device with scraper ring
By introducing a scraper ring design into the piston-cylinder unit, the problem of uneven lubricant distribution was solved, achieving uniform lubricant distribution and temperature adaptability, thus improving the lubrication effect and stability of the device.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ROBERT BOSCH GMBH
- Filing Date
- 2020-05-26
- Publication Date
- 2026-06-02
AI Technical Summary
In the prior art, the lubricant distribution between the piston and the cylinder is uneven, resulting in poor lubrication. Furthermore, the lubricant tends to accumulate when the temperature changes, affecting the normal operation of the device.
The design employs a scraper ring, which forms an annular space between the scraper ring, the piston, and the cylinder. The movement of the scraper ring distributes the lubricant evenly on the cylinder bore wall, compensating for changes in radial width and diameter. The scraper ring material has a lower hardness than the contact components to reduce friction and moves with the piston.
It achieves uniform distribution of lubricant, reduces lubricant accumulation, improves the lubrication effect and operational stability of the device, and adapts to dimensional changes caused by temperature variations.
Smart Images
Figure CN111997960B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a scraper ring and a device having the features of the preamble of claim 2. Background Technology
[0002] This invention relates to a scraper ring and a device having the features of the preamble of claim 2. In particular, the device is a piston-cylinder unit or has a piston-cylinder unit, which is particularly configured to generate braking pressure and / or to deliver brake fluid in hydraulic, especially slip-adjustable, vehicle braking systems. Summary of the Invention
[0003] The device according to the invention, having the features of claim 2, has an outer component with a cylindrical hole and an inner component, preferably also cylindrical, capable of axial movement within the hole. The cross-section of the inner component is smaller than the cross-section of the hole in the outer component for at least a portion of the length along the direction of movement of the inner component within the hole of the outer component, thereby creating a gap or free space, referred to herein as an "annular space," between the inner component and the hole wall of the hole in the outer component, for at least a portion of the length. A scraper ring is present in the annular space, surrounding the inner component within the annular space. The scraper ring preferably abuts against the hole wall of the hole in the outer component on its outer circumference and / or against the inner component on its inner circumference, thereby enabling a seal between the scraper ring and the outer component and / or between the scraper ring and the outer component, but this is not mandatory. If the scraper ring provides a seal, it can also be understood as a sealing ring.
[0004] The scraper ring is configured to distribute lubricant along the direction of movement of the inner component within the bore of the outer component, and for this purpose, moves with the inner component as it moves within the bore of the outer component. The scraper ring either moves completely with the inner component and, in this case, participates in the complete travel of the inner component, or it moves only partially with the inner component and travels a distance less than that of the inner component. Through the movement of the scraper ring as the inner component moves, it distributes lubricant along the direction of movement of the inner component onto the bore wall of the bore in the outer component. The scraper ring prevents the inner component from causing the lubricant to move along the direction in which it collects and remains during its movement, thus ensuring that for most of the length of the bore in the outer component, there is little or no lubricant present on the bore wall along the direction of movement of the inner component.
[0005] The scraping ring compensates for changes in the radial width and / or diameter of the annular space. The dimensions of the annular space may change, for example, due to temperature variations.
[0006] The scraper ring is preferably made of a material having a lower hardness than the component surrounding the annular space and / or the component in contact with the scraper ring, and is the subject of claim 1 as a single piece.
[0007] The subject matter of the dependent claims is the improvement and advantageous design of the invention described in the independent claims.
[0008] The device according to the invention is in particular a piston-cylinder unit or having a piston-cylinder unit, wherein the cylinder of the piston-cylinder unit forms an outer component with a hole, and the piston, as an inner component, is axially movable, i.e., movable (claim 10), within the hole. The piston has a dimension smaller than the cylinder for at least a portion of its length, thus creating the annular space described above in that portion of its length. By moving the piston in the cylinder or conversely by moving the cylinder on the piston, the piston draws fluid into the cylinder, expels fluid from the cylinder, and / or generates pressure in the cylinder. In hydraulic vehicle braking devices, the fluid is brake fluid. The piston-cylinder unit can also be used as an actuator to generate linear motion by: conversely, by supplying pressurized fluid to the cylinder, which causes the piston to move in the cylinder or conversely, causes the cylinder to move on the piston.
[0009] All features disclosed in the specification and drawings can be implemented individually or in virtually any combination in embodiments of the invention. The following embodiments of the invention are possible in principle, and these embodiments do not possess all the features of the claims or embodiments of the invention, but only one or more of them. Attached Figure Description
[0010] The invention will now be explained in detail with the aid of embodiments shown in the accompanying drawings. Wherein:
[0011] Figure 1 A cross-sectional view of the piston-cylinder unit according to the invention is shown;
[0012] Figure 2 The scraper ring of the piston-cylinder unit is shown in perspective; and
[0013] Figure 3 It shows Figure 2 The enlarged annular cross-section of the scraper ring in the installed state.
[0014] The attached diagram is a simplified illustration. Detailed Implementation
[0015] exist Figure 1The piston-cylinder unit 1 according to the invention shown has a cylinder 2 and a piston 3, the piston being movable within the cylinder 2. The piston-cylinder unit 1 can also generally be understood as a device 31 according to the invention, having a cylinder 2 with a bore 33 as an outer component 32 and a piston 3 as an inner component 34, the inner component being axially movable within the bore 33 of the outer component 32. The inner circumferential surface of the cylinder 2 generally forms the bore wall 35 of the device 31 according to the invention. The cylinder 2 has a closed end with a cylinder bottom 4 and an open end.
[0016] The piston 3 is a tubular hollow piston, and its end facing the cylinder bottom 4 is closed by a piston bottom 5 integral with the piston 3.
[0017] To move the piston 3 within the cylinder 2, there exists an electric motor 6 (shown as circuit symbols in the drawings), a planetary gear transmission 7 as a mechanical reducer, and a ball screw drive, which can generally be understood as a helical drive 8. The main shaft 9 of the ball screw drive is coaxially arranged within the piston 3 and rigidly connected to the piston 3 by means of a journal 10 pressed into the piston bottom 5. The electric motor 6, the planetary gear transmission 7, and the ball screw drive, or generally the helical drive 8, form an electromechanical drive mechanism for moving the piston 3 within the cylinder 2 or, generally, for moving the inner component 34 within the bore 33 of the outer component 32.
[0018] The tubular spindle nut 11, which surrounds the spindle 9, extends coaxially through its open end into the piston 3, which is constructed as a hollow piston, and extends axially a short distance from the cylinder 2 and the piston 3. Outside the cylinder 2, the spindle nut 11 is rotatably supported on the open end of the cylinder 2 by a swivel bearing 12—in this embodiment, a ball bearing.
[0019] The main shaft 9 of the helical transmission device 8 simultaneously forms the planet carrier of the planetary gear transmission mechanism 7, which is also coaxially arranged outside the piston 3 and cylinder 2. The planetary gears 13 of the planetary gear transmission mechanism 7 are rotatably supported on the end of the main shaft nut 11 extending from the cylinder 2. The hollow wheel 14 of the planetary gear transmission mechanism 7 is rigidly fixed on the outer ring of the rotary bearing 12. The sun gear 15 of the planetary gear transmission mechanism 7 can be rotatably driven by the electric motor 6. The rotation of the sun gear 15 drives the main shaft nut 11 to rotate via the planetary gears 13, which in turn drives the piston 3 to move within the cylinder 2 via the main shaft 9.
[0020] The piston 3 is sealed by two piston seals 18 in the cylinder 2. The piston seals 18 are arranged in a surrounding groove in the middle region of the cylinder 2 along the direction of movement of the piston 3. Between the cylinder bottom 4 and the piston seals 18, and between the piston seals 18 and the open end of the cylinder 2, the cylinder 2 has an inner diameter larger than the outer diameter of the piston 3, thus creating a gap that surrounds the piston 3 in the cylinder 2. This gap between the piston seals 18 and the open end of the cylinder 2 is referred to herein as the annular space 19.
[0021] To prevent rotation of the piston 3 and the main shaft 9 of the screw drive 8, which is rigidly connected to the piston, a pin serving as an anti-rotation element 20 is arranged parallel to the shaft in the annular space 19. Half of the pin's cross-section is located in a groove parallel to the shaft, which has a semi-circular cross-section and is situated in the annular space 19 on the inner circumference of the cylinder 2. The other half of the pin constituting the anti-rotation element 20 extends into the annular space 19.
[0022] In this embodiment, the piston 3 has a circumferential annular edge 21 extending radially outward at its open end in the shape of a flange. This annular edge has a semi-circular gap into which the pin forming the anti-rotation element 20 is fitted. Thus, the piston 3 is held in the cylinder 2, and generally the inner component 34 is held in the hole 33 of the outer component 32, in a movable and torsional manner. This embodiment has three anti-rotation elements 20 evenly distributed circumferentially. The number, arrangement, and shape of the anti-rotation elements 20 can vary. The anti-rotation elements are not necessarily pins, but can also be, for example, ribs (not shown) extending inward from the cylinder 2 in the annular space 19 along the direction of piston 3 movement.
[0023] On the piston 3, a scraper ring 22 is arranged in the annular space 19. This scraper ring is, for example, made of plastic and Figure 2 It is shown as a single item. Figure 3 An annular cross-section is shown, in which... Figure 3 The closed ends of cylinder 2 and piston 3 are located below, and the open ends of cylinder 2 and piston 3 are located above. The scraper ring 22 has a trapezoidal annular cross-section, and the inner circumferential surface 23 of the scraper ring 22 (in...) Figure 3 (Middle left) and outer circumferential surface 24 (in) Figure 3(Right side) is a truncated cone surface, wherein the inner circumferential surface 23 of the scraper ring 22 widens towards the open end of the cylinder 2 and the outer circumferential surface 24 of the scraper ring 22 tapers towards the open end of the cylinder 2, such that the scraper ring 22 abuts against the piston 3 on its inner circumference 23 with a surrounding, acute-angled edge 25 and abuts against the inner side of the cylinder 2 on its outer circumference 24 in the annular space 19 with a surrounding, acute-angled edge 26. The two acute-angled edges 25, 26 are located at the transition from the inner circumferential surface 23 or from the outer circumferential surface 24 to the end face of the scraper ring 22 towards the closed end of the cylinder 2. Because the annular cross-section of the scraper ring 22 is trapezoidal, the scraper ring can move more easily towards its open end than towards the closed end of the cylinder 2. This annular cross-section is a radial section at one circumferential position of the scraper ring 22.
[0024] In the end face facing the open end of cylinder 2, the scraper ring 22 has a surrounding groove 27, which can also be understood as a recess.
[0025] Within the outer circumferential surface 24, the scraper ring 22 has semi-circular gaps 28 for forming the pins of the anti-rotation element 20. The arrangement and shape of the gaps 28 correspond to the anti-rotation element 20, which is not necessarily a pin, as explained.
[0026] The friction between the scraper ring 22 and the piston 3 is greater than the friction between the scraper ring 22 and the cylinder 2. Therefore, the scraper ring 22 moves with the piston 3 as the piston 3 moves within the cylinder 2, and thus the lubricant is distributed within the annular space 19 along the direction of piston 3 movement onto the cylinder 2. Furthermore, the scraper ring 22 distributes the lubricant onto the pins forming the anti-rotation element 20.
[0027] The friction between the scraper ring 22 and the piston 3 is higher than the friction between the scraper ring 22 and the cylinder 2. This can be achieved, for example, through the material pairing, surface roughness and / or surface structure of the piston 3 and the cylinder 2, and / or through the design of the scraper ring 22 abutting against the piston 3 on the inside with a greater stress than it abuts against the cylinder 2 on the outside, and / or through the shape of the annular cross-section of the scraper ring 22. The scraper ring 22 can move completely with the piston 3 or it can remain behind the piston 3, that is, perform a shorter stroke than the piston 3.
[0028] The scraper ring 22, with its surrounding, acute-angled edges 25 and 26, rests against the piston 3 on its inner side and against the cylinder 2 on its closed end face facing the cylinder 2 under mechanical stress. In other words, it can be said that it is clamped between the piston 3 and the cylinder 2 on its acute-angled edges 25 and 26. Bending stress exists in the annular cross-section, causing the annular cross-section of the scraper ring 22 to arch towards the open end of the cylinder 2. The surrounding groove 27 in the end face of the scraper ring 22 facing the open end of the cylinder 2 reduces the axial thickness of the annular cross-section and supports the bending of the annular cross-section.
[0029] Furthermore, the surrounding groove 27 in the end face of the scraper ring 22 facing the open end of the cylinder 2 forms a lubricant container. When the scraper ring 22 moves together with the piston 3 toward the open end of the cylinder 2, the lubricant is collected in the lubricant container. When the piston 3 moves in the opposite direction toward the closed end of the cylinder 2, the flange-like edge 21 of the piston 3, which extends radially outward on the open end of the piston 3, distributes the lubricant in the annular space 19 along the direction of movement onto the cylinder 2.
[0030] During assembly, before subsequently applying grease, which serves as a lubricant, from the annular space 19 to the cylinder 2 and before the piston 3 is placed into the cylinder 2 and the scraper ring 22, the scraper ring 22 is inserted into the cylinder 2 all the way to the end of the annular space 19 near the piston seal 18.
[0031] The piston-cylinder unit 1, together with the electric motor 6, planetary gear transmission mechanism 7, and helical transmission device 8, forms the external force-brake pressure generator of a piston pump assembly for a hydraulic vehicle braking device with a slip adjustment mechanism (not shown in other aspects). Such a slip adjustment mechanism is, for example, an anti-lock braking system (ABS), a drive slip adjustment mechanism, and a ride power adjustment mechanism, or an electronic stability program, commonly abbreviated as ABS, ASR, FDR, or ESP. The piston pump assembly has a square hydraulic block 29 with a through-hole, in this embodiment, into which the cylinder 2 is inserted such that the cylinder extends on both sides. Alternatively, the cylinder 2 and the hydraulic block 29 can be integrated into a cylindrical cavity (not shown).
[0032] In this embodiment, the hydraulic block 29 additionally has a main brake cylinder bore 30 for a main brake cylinder (not shown) that can be operated by muscle force. The hydraulic block 29 is used to mechanically fix and hydraulically connect the hydraulic and electro-hydraulic structural elements of the slip adjustment mechanism. These structural elements, in addition to having an external force-braking pressure generator for the piston cylinder unit 1 according to the invention, including an electric motor 6, a planetary gear transmission mechanism 7, and a helical transmission device 8, include a solenoid valve (not shown), a check valve, a hydraulic accumulator, and a damping chamber. These components are arranged within and above the hydraulic block 29 and are hydraulically connected to each other via a drilled structure (not shown) in the hydraulic block 29 according to the hydraulic circuit diagram of the external force-vehicle braking device and the slip adjustment mechanism. With these structural elements assembled, the hydraulic block 29 forms a hydraulic unit for generating muscle force- and / or external force-braking pressure and for slip adjustment of the hydraulic vehicle braking device (not shown in other respects). Such a sliding adjustment mechanism and hydraulic block 29 are known to those skilled in the art and will not be explained in detail here.
Claims
1. A device for a vehicle braking system, comprising an outer component (32) having a cylindrical hole (33) and an inner component (34) axially movable within the hole (33) of the outer component (32), wherein the cross-section of the inner component is smaller than the cross-section of the hole (33) in the outer component (32), thereby creating an annular space (19) between the hole wall (35) of the hole (33) in the outer component (32) and the inner component (34), characterized in that, A scraper ring (22) is arranged in the annular space (19) surrounding the inner component (34) within the annular space (19). The scraper ring moves together with the inner component (34) when the inner component (34) moves axially relative to the outer component (32). The outer component (32) has an anti-rotation element (20) extending along the direction of movement of the inner component (34). The anti-rotation element extends inward from the hole wall (35) toward the inner component (34) in the annular space (19). The inner component (34) is movably supported on the anti-rotation element in the circumferential direction to prevent rotation. The scraper ring (22) has a gap (28) for the anti-rotation element (20) in its outer circumferential surface (24). The inner component (34) has an outwardly extending annular edge (21) with a gap for the anti-rotation element (20).
2. The device for vehicle braking equipment according to claim 1, characterized in that, The scraper ring (22) has a higher friction on the inner part (34) than on the hole wall (35) of the hole (33) in the outer part (32).
3. The apparatus for vehicle braking devices according to claim 1 or 2, characterized in that, The inner circumferential surface (23) of the scraper ring (22) expands along the axial direction and / or the outer circumferential surface (24) of the scraper ring (22) tapers along the axial direction.
4. The apparatus for vehicle braking devices according to claim 1 or 2, characterized in that, The scraper ring (22) has a circumferential groove (27) in its end face.
5. The apparatus for a vehicle braking device according to one or more of claims 1 to 4, characterized in that, The device (31) has an electromechanical drive (6, 7, 8) for moving the inner part (34) in the hole (33) of the outer part (32).
6. The apparatus for a vehicle braking device according to one or more of claims 1 to 5, characterized in that, The annular space (19) has a lubricant filling section.
7. The apparatus for a vehicle braking device according to one or more of claims 1 to 6, characterized in that, The device (31) has a piston-cylinder unit (1), which has a cylinder (2) as an outer part (32) and a piston (3) as an inner part (34) that can move in the cylinder (2), with an annular space (19) between the outer part and the inner part, and the scraper ring (22) arranged in the annular space.
8. A hydraulic block for a vehicle braking device with external force regulation or a hydraulic vehicle braking device with slip regulation, the hydraulic vehicle braking device having a piston and cylinder unit as an external force braking pressure generator as described in claim 7 or for delivering brake fluid, wherein the cylinder (2) of the piston and cylinder unit (1) is arranged in the hydraulic block (29).
9. A hydraulic vehicle braking device having a piston and cylinder unit as an external braking pressure generator as described in claim 7 or 8, or for supplying brake fluid.