Rolling friction hydraulic cylinder

Abstract

The utility model relates to the technical field of hydraulic cylinders, in particular to a rolling friction hydraulic cylinder which comprises a cylinder barrel and a piston rod inserted into the cylinder barrel in the axial direction of the cylinder barrel. The piston is arranged at the end part of the piston rod in a sleeving manner; a ball guide sleeve is arranged between the cylinder barrel and the piston rod, a rolling groove is formed in the inner side wall of the ball guide sleeve, and a plurality of balls are arranged in the rolling groove so that the ball guide sleeve can be matched with the piston rod in a rolling mode. The rolling grooves allowing the balls to circularly roll are formed, the deep and shallow design of the rolling grooves enables only part of the balls making contact with the piston rod to roll in the axial direction of the cylinder barrel, and therefore rolling friction is formed between the piston rod and the ball guide sleeve, friction between the piston rod and the ball guide sleeve is reduced, and the use reliability of equipment is improved.

Description

Technical Field

[0001] This application relates to the field of hydraulic cylinder technology, and more particularly to a rolling friction hydraulic cylinder. Background Technology

[0002] In conventional hydraulic cylinders, the seals on the guide sleeve side mainly consist of dust rings, rod seals, buffer rings, and guide rings. These seals ensure a tight seal between the guide sleeve and the piston rod, preventing hydraulic oil from leaking out of the cylinder. The guide ring serves to support and guide the piston, preventing metal-to-metal contact between the guide sleeve and the piston rod.

[0003] For some slender hydraulic cylinders with side loads, such as the telescopic hydraulic cylinders of aerial work platforms, which have the significant characteristics of small cylinder diameter and long stroke, the existing guide sleeve structure is mostly a surface contact sliding friction, and the friction of the guide sleeve part is large, which makes the hydraulic cylinder very prone to creeping and shaking when it is in operation, resulting in reduced equipment reliability. Utility Model Content

[0004] The technical problem to be solved by this utility model is that when the existing hydraulic cylinder is operated, the friction between the guide sleeve and the piston rod is large, resulting in low equipment reliability.

[0005] Therefore, this utility model provides a rolling friction hydraulic cylinder.

[0006] The technical solution adopted by this utility model to solve its technical problem is:

[0007] A rolling friction hydraulic cylinder, comprising,

[0008] Cylinder barrel, and piston rod inserted into the cylinder barrel along the cylinder barrel axis;

[0009] A piston, which is sleeved on the end of the piston rod;

[0010] A ball bearing guide sleeve is provided between the cylinder and the piston rod. The inner side wall of the ball bearing guide sleeve is provided with a rolling groove, and a plurality of balls are provided in the rolling groove so that the ball bearing guide sleeve and the piston rod can roll together.

[0011] Furthermore, a ball bearing piston sleeve is provided between the cylinder and the piston. The outer wall of the ball bearing piston sleeve is provided with a rolling groove, and a plurality of balls are provided in the rolling groove so that the ball bearing piston sleeve and the cylinder can roll together.

[0012] Furthermore, the balls are divided into multiple groups, and the rolling trajectory of each group of balls is a closed loop. At least one segment of the rolling trajectory is in rolling engagement with the piston rod or cylinder.

[0013] Furthermore, the ball bearing guide sleeve includes a bearing sleeve and a retainer. The bearing sleeve is coaxially disposed inside the cylinder, and the retainer is coaxially disposed inside the bearing sleeve. The rolling groove is disposed on the retainer, and the balls circulate and roll in the rolling groove. Some of the balls in the rolling groove roll and engage with the piston rod.

[0014] Furthermore, multiple rolling grooves are provided along the circumference of the ball guide sleeve or the ball piston sleeve.

[0015] Furthermore, in each of the rolling grooves, the portion of the rolling groove containing the ball that rolls with the cylinder or piston rod is the working section, and the working section in each of the rolling grooves is arranged along the axial direction of the cylinder.

[0016] Furthermore, along the radial direction of the cylinder, the length H of the portion of the ball exposed in the rolling groove within the working section is greater than the length h of the portion of the ball exposed in the rolling groove when the ball is located in other parts of the rolling groove besides the working section.

[0017] Furthermore, a guide sleeve is provided between the cylinder and the piston rod, and the guide sleeve is located between the cylinder and the ball bearing guide sleeve.

[0018] Furthermore, the guide sleeve and the ball guide sleeve are fixed together by fasteners.

[0019] Furthermore, the outer wall of the piston is provided with an annular groove, and the ball piston sleeve is disposed within the annular groove.

[0020] The beneficial effects of this utility model are that a rolling groove is provided on the inner side wall of the ball guide sleeve to allow the balls to circulate. The balls circulate in the rolling groove, and the rolling direction of the balls that roll with the piston rod in the rolling groove is set along the axial direction of the piston rod. Thus, rolling friction is formed between the piston rod and the ball guide sleeve, reducing the friction between the piston rod and the ball guide sleeve. The design of the rolling groove depth allows only the part of the balls that contact the cylinder and piston rod to roll along the axial direction of the cylinder, thereby reducing the friction of the balls in the rolling groove. The balls can move along the rolling trajectory instead of rolling in place, thereby further reducing the friction.

[0021] This compact structure is suitable for high-speed, high-frequency, and long-stroke reciprocating motion. Because it is used in clean hydraulic oil, it has a longer service life and higher durability. Furthermore, both the ball bearing guide sleeve and the ball bearing piston have multiple rolling grooves; the support of these multiple balls enhances the cylinder's resistance to lateral loads, making it more reliable than conventional guide ring structures. Attached Figure Description

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0023] Figure 1This is a schematic diagram of the structure of the rolling friction hydraulic cylinder in this utility model.

[0024] Figure 2 This is a schematic diagram of the structure of the ball bearing guide sleeve in this utility model.

[0025] Figure 3 This is a schematic diagram of the ball piston sleeve in this utility model.

[0026] Figure 4 This is a structural schematic diagram illustrating the rolling fit between the ball and the piston rod in this utility model.

[0027] Figure 5 This is a structural schematic diagram illustrating the rolling fit between the ball bearings and the cylinder in this utility model.

[0028] In the diagram: 1. Cylinder; 2. Piston rod; 3. Piston; 31. Annular groove; 32. Ball piston sleeve; 4. Guide sleeve; 5. Ball guide sleeve; 51. Bearing sleeve; 52. Retainer; 53. Rolling groove; 531. Actuating section; 6. Ball. Detailed Implementation

[0029] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the present invention, and therefore only show the components relevant to the present invention.

[0030] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, features defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0031] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0032] Reference Figure 1 A rolling friction hydraulic cylinder includes a cylinder barrel 1, a piston rod 2, a piston 3, a guide sleeve 4 and a ball guide sleeve 5 disposed between the cylinder barrel 1 and the piston rod 2. The piston rod 2 is coaxially inserted into the cylinder barrel 1 and slides axially with the cylinder barrel 1. The piston 3 is fixedly connected to the end of the piston rod 2 inserted into the cylinder barrel 1. The guide sleeve 4 is disposed in the cylinder barrel 1 and fixedly connected to the cylinder barrel 1. A plurality of balls 6 are rolled on the inner side wall of the ball guide sleeve 5, and the balls 6 are rolled between the piston rod 2 and the ball guide sleeve 5.

[0033] Specifically, refer to Figure 2 A guide sleeve 4 and a ball guide sleeve 5 are provided between the piston rod 2 and the cylinder 1. The ball guide sleeve 5 is sleeved on the piston rod 2, and the guide sleeve 4 is provided between the ball guide sleeve 5 and the cylinder 1. The guide sleeve 4 and the ball guide sleeve 5 are fixed by fasteners (such as bolts). The ball guide sleeve 5 includes a bearing sleeve 51 and a retainer 52. The retainer 52 is coaxially provided inside the bearing sleeve 51, and a rolling groove 53 is provided on the retainer 52.

[0034] A ball piston sleeve 32 is installed on the outer side wall of the piston 3. An annular groove 31 for installing the ball piston sleeve 32 is provided on the outer side wall of the piston 3. A rolling groove 53 is also provided on the outer side wall of the ball piston sleeve 32. Multiple rolling grooves 53 on the retainer 52 and multiple rolling grooves 5 on the ball piston sleeve 32 can be provided along the circumference of the ball guide sleeve 5 or the ball piston sleeve 32. Several balls 6 are provided in the rolling grooves 53 on the retainer 52 and multiple rolling grooves 5 on the ball piston sleeve 32.

[0035] like Figure 3 As shown, the rolling groove 53 is configured as a closed ring, and the rolling trajectory of the balls 6 in the rolling groove 53 is a closed loop. Some of the balls 6 in the rolling groove 53 on the ball piston sleeve 32 roll and engage with the inner sidewall of the cylinder 1, and some of the balls 6 in the rolling groove 53 on the retainer 52 roll and engage with the piston rod 2. In this embodiment, the rolling groove 53 is arranged in a racetrack shape, with the long side of the rolling groove 53 arranged along the axial direction of the guide sleeve 4, and the two long sides of the rolling groove 53 transition smoothly. The balls 6 are embedded in the rolling groove 53 and roll.

[0036] It should be noted that, referring to Figure 4 ,5 In each rolling groove 53, the portion of the rolling groove 53 where the ball 6 abuts against and rolls with the piston rod 2 and cylinder 1 is the working section 531. Along the radial direction of the cylinder 1, the length H of the portion of the ball 6 exposed in the working section 531 that extends into the rolling groove 53 is greater than the length h of the portion of the ball 6 exposed in the rolling groove 53 when the ball 6 is located in other parts of the rolling groove 53 besides the working section 531 (h can be negative, meaning the ball 6 is completely embedded in the rolling groove 53, see reference). Figure 2 , 3 The non-operating section rolling groove 53 is formed within the wall thickness of the piston 3 and the retainer 52, and the ball 6 is completely embedded in the non-operating section rolling groove 53. Taking this embodiment as an example, the depths of the two long sides of the rolling groove 53 are inconsistent, with one side of the rolling groove 53 being deeper than the other. The shallower side is the operating section 531, and there is a smooth transition between the two long sides. When the ball 6 is in the operating section 531 of the rolling groove 53, the ball 6 is exposed at the opening of the rolling groove 53 and abuts against the piston rod 2 or the cylinder 1 and rolls in cooperation. When the ball 6 is located in other parts of the rolling groove 53, the ball 6 does not contact the piston rod 2 or the cylinder 1, or is completely embedded in the rolling groove 53. Thus, the ball 6 in the operating section 531 rolls in cooperation with the piston rod 2, allowing the ball 6 to smoothly circulate within the rolling groove 53.

[0037] This application provides rolling grooves 53 on the inner wall of the guide sleeve 4 and the outer wall of the piston 3, allowing the balls 6 to circulate. The balls 6 circulate within the rolling grooves 53, and the rolling direction of the balls 6 that roll in cooperation with the piston rod 2 and the cylinder 1 is set along the axial direction of the piston rod 2. This creates rolling friction between the piston rod 2 and the guide sleeve 4, and between the piston 3 and the inner wall of the cylinder 1, thereby reducing the friction between the piston rod 2 and the guide sleeve 4, and between the piston 3 and the cylinder 1.

[0038] The design of the rolling groove 53 with varying depths allows only the portion of the ball 6 in contact with the cylinder 1 and piston rod 2 to roll along the axial direction of the cylinder 1, thereby reducing the friction of the ball 6 within the rolling groove 53. The ball 6 can move along the rolling trajectory instead of rolling in place, which further reduces friction. The rolling of the ball 6 can provide high-precision support for the guide, ensuring the stability and accuracy of the cylinder operation.

[0039] This compact structure is suitable for high-speed, high-frequency, and long-stroke reciprocating motion. Because it is used in clean hydraulic oil, it has a longer service life and higher durability. Furthermore, both the ball bearing guide sleeve 6 and the ball bearing piston 3 have multiple rolling grooves 53, and the support of multiple sets of balls 6 makes the cylinder more resistant to lateral loads, making it more reliable than conventional guide ring structures.

[0040] Based on the above-described preferred embodiments of this utility model, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined by the scope of the claims.

Claims

1. A rolling friction hydraulic cylinder, characterized in that, include, Cylinder (1), and piston rod (2) inserted into cylinder (1) along the axial direction of cylinder (1); Piston (3), the piston (3) being sleeved on the end of the piston rod (2); A ball bearing guide sleeve (5) is provided between the cylinder (1) and the piston rod (2). A rolling groove (53) is provided on the inner side wall of the ball bearing guide sleeve (5). A plurality of balls (6) are provided in the rolling groove (53) so that the ball bearing guide sleeve (5) and the piston rod (2) can roll together.

2. The rolling friction hydraulic cylinder according to claim 1, characterized in that, A ball piston sleeve (32) is provided between the cylinder (1) and the piston (3). A rolling groove (53) is provided on the outer side wall of the ball piston sleeve (32). A plurality of balls (6) are provided in the rolling groove (53) so that the ball piston sleeve (32) and the cylinder (1) can roll together.

3. The rolling friction hydraulic cylinder according to claim 1 or 2, characterized in that, The ball bearings (6) are divided into multiple groups, and the rolling trajectory of each group of ball bearings (6) is a closed loop. At least one segment of the rolling trajectory of the ball bearings (6) is in rolling contact with the piston rod (2) or the cylinder (1).

4. The rolling friction hydraulic cylinder according to claim 1, characterized in that, The ball guide sleeve (5) includes a bearing sleeve (51) and a retainer (52). The bearing sleeve (51) is coaxially disposed inside the cylinder (1). The retainer (52) is coaxially disposed inside the bearing sleeve (51). The rolling groove (53) is disposed on the retainer (52). The ball (6) circulates in the rolling groove (53). Some of the balls (6) in the rolling groove (53) roll in cooperation with the piston rod (2).

5. The rolling friction hydraulic cylinder according to claim 1, characterized in that, The rolling groove (53) is provided in multiple ways along the circumference of the ball guide sleeve (5) or the ball piston sleeve (32).

6. The rolling friction hydraulic cylinder according to claim 1, characterized in that, In each of the rolling grooves (53), the portion of the rolling groove (53) where the ball (6) rolls in cooperation with the cylinder (1) or piston rod (2) is located is the working section (531), and the working section (531) in each of the rolling grooves (53) is arranged along the axial direction of the cylinder (1).

7. The rolling friction hydraulic cylinder according to claim 6, characterized in that, Along the radial direction of the cylinder (1), the length H of the portion of the ball (6) exposed in the rolling groove (53) in the working section (531) is greater than the length h of the portion of the ball (6) exposed in the rolling groove (53) when it is in other parts of the rolling groove (53) other than the working section (531).

8. The rolling friction hydraulic cylinder according to claim 1, characterized in that, A guide sleeve (4) is also provided between the cylinder (1) and the piston rod (2), and the guide sleeve (4) is located between the cylinder (1) and the ball guide sleeve (5).

9. The rolling friction hydraulic cylinder according to claim 8, characterized in that, The guide sleeve (4) and the ball guide sleeve (5) are fixed together by fasteners.

10. The rolling friction hydraulic cylinder according to claim 1, characterized in that, The outer wall of the piston (3) is provided with an annular groove (31), and the ball piston sleeve (32) is disposed in the annular groove (31).

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