Crimped retained hydraulic cylinder head and cover

Abstract

A hydraulic cylinder can include a cylindrical tube, a piston head having a piston rod disposed within the cylindrical tube, a cylinder head secured in one tube end of the cylindrical tube and having the piston rod extending through an opening of the piston rod, and a cylinder cover having a cover seal portion inserted into an opposite tube end of the cylindrical tube. The tube ends are crimped down onto the cover seal portion such that tube material of the cylindrical tube is disposed within a plurality of annular cover grooves in the cover seal portion to retain the cylinder cover. The cylinder head can have a similar plurality of annular head grooves into which respective tube ends are crimped down onto the cylinder head.

Description

Technical Field

[0001] The present invention generally relates to hydraulic cylinders for working machines, and more specifically, to hydraulic cylinders having a head and a cover held by a pressing operation. Background Technology

[0002] Numerous operator-driven work machines have been developed for performing excavation operations on work surfaces, such as asphalt pavers, backhoe loaders, cold planers, compactors, bulldozers, drilling rigs, excavators, material handlers, automatic graders, skid-steer loaders, and wheel loaders. Typically, these work machines include one or more work implements mounted on another machine body, which can move along the ground on wheels or tracks. Stabilizing outriggers may also be included to hold the work machine in place while the operator uses tools. The movement of the implements and stabilizing outriggers can be controlled using actuators such as hydraulic cylinders.

[0003] Hydraulic cylinders for controlling components in operating machinery are known in the art. For example, International Publication No. WO2005111432, entitled "Hydraulic Cylinder" published on November 24, 2005, discloses a hydraulic cylinder having a tube with a cap connected to a first axial end of the tube and a head connected to another axial end of the tube. A piston is axially slidable within the tube and is configured to seal the inner surface of the tube when it slides. The piston has a rod connected thereto, which passes through and seals the cylinder head when the cylinder head moves with the piston. A conduit is provided for connection, in use, to a hydraulic fluid source via a suitable supply line to control the fluid pressure on at least one side of the piston within the tube, thereby controlling the axial movement of the piston within the tube. The end of the tube is mechanically configured to engage with at least one of the cap and the head, thereby permanently and fluid-tightly securing the tube thereto.

[0004] Current constructions of hydraulic cylinders can retain the head in the end of the tube by providing an interference fit torque or a retaining ring, and can retain the cap by engaging threads, a retaining ring, or welding. Such connection mechanisms may not provide sufficient strength to retain the head and cap, and can make the manufacture of hydraulic cylinders time-consuming and expensive. Summary of the Invention

[0005] In one aspect of the invention, a hydraulic cylinder is disclosed. The hydraulic cylinder may include: a cylindrical tube having an inner surface, an outer surface, a first end, a second end opposite to the first end, and a first fluid port near the first end; a piston head disposed within the cylindrical tube; a piston rod connected to the piston head and extending outwardly from the cylindrical tube through the second end; and a cylinder head having a piston rod opening that receives and allows the piston rod to slide through the opening; wherein the cylinder head is inserted into and engaged by the second end of the cylindrical tube to retain the cylinder head therein, and the cylinder head has a cap sealing portion and a cylinder attachment portion having a cylindrical shape. The cap sealing portion may have multiple annular cap grooves defined in the outer surface of the sealing portion. The cap sealing portion may be inserted into the first end of the tube, and the outer surface of the tube near the first end of the tube is pressed downward onto the cap sealing portion, such that the tube material of the cylindrical tube is disposed in the multiple annular cap grooves on the inner surface of the tube near the first end of the tube, so as to retain the cap sealing portion in the first end of the tube and seal the first end of the cylindrical tube.

[0006] In another aspect of the invention, a method for manufacturing a hydraulic cylinder is disclosed. The method may include: forming a plurality of annular cover grooves in the outer surface of a sealing portion of a cover sealing portion of a cylinder head; inserting the cover sealing portion into a first end of a cylindrical tube of the hydraulic cylinder; and pressing the outer surface of the cylindrical tube adjacent to the first end of the tube downwards onto the cover sealing portion, such that the tube material of the cylindrical tube at the inner surface adjacent to the first end of the tube is disposed in the plurality of annular cover grooves to retain the cover sealing portion within the first end of the tube and seal the first end of the cylindrical tube.

[0007] In another aspect of the invention, a hydraulic cylinder is disclosed. The hydraulic cylinder may include a cylindrical tube having an inner surface, an outer surface, a first end, a second end opposite to the first end, and a first fluid port near the first end; a piston head disposed within the cylindrical tube; a piston rod connected to the piston head and extending outward from the cylindrical tube through the second end; and a cylinder head having a piston rod opening for receiving the piston rod and allowing the piston rod to slide through. The cylinder head may have a plurality of annular head grooves defined in an outer surface. The cylinder head is inserted into the second end of the tube, and the outer surface of the tube near the second end is pressed downward against the cylinder head, such that the tube material of the cylindrical tube is disposed in the plurality of annular head grooves on the inner surface near the second end to retain the cylinder head within the second end and seal the second end of the cylindrical tube.

[0008] Additional aspects are defined by the claims of this patent. Attached Figure Description

[0009] Figure 1This is a side view of an exemplary working machine in which the hydraulic cylinder according to the present invention can be implemented;

[0010] Figure 2 This is a partial cross-sectional side view of an embodiment of a hydraulic cylinder according to the present invention;

[0011] Figure 3 Before the first end of the press-fit pipe Figure 2 An enlarged partial cross-sectional side view of the cylinder head and the first end of the cylindrical tube of the hydraulic cylinder.

[0012] Figures 3A to 3E yes Figure 3 An enlarged cross-sectional view of a portion of the cylinder head, showing the alternative annular cover groove geometry;

[0013] Figure 4 After the first end of the press-fit pipe Figure 3 Enlarged partial cross-sectional side view of the first end of the tube and the cylinder head;

[0014] Figure 5 This is an enlarged partial cross-sectional side view of the first end of the pipe before the first end of the press-fit pipe and the cylinder head, according to an alternative embodiment of the hydraulic cylinder of the present invention.

[0015] Figure 6 This is an enlarged partial cross-sectional side view of the first end of the pipe before the first end of the press-fit pipe and the cylinder head, according to another alternative embodiment of the hydraulic cylinder of the present invention.

[0016] Figure 7 This is an enlarged partial cross-sectional side view of the first end of the pipe before the first end of the press-fit pipe and the cylinder head, according to another embodiment of the hydraulic cylinder of the present invention.

[0017] Figure 8 After the second end of the crimping pipe Figure 2 An enlarged partial cross-sectional side view of the second end of the cylindrical tube and the cylinder head of the hydraulic cylinder.

[0018] Figure 9 This is an enlarged partial cross-sectional side view of the first end of the pipe before the first end of the press-fit pipe and the cylinder head, according to yet another embodiment of the hydraulic cylinder of the present invention; and

[0019] Figure 10 It is according to the invention for use Figure 2 A flowchart of an exemplary hydraulic cylinder manufacturing process. Detailed Implementation

[0020] Figure 1An exemplary working machine 10 in the form of a backhoe loader is shown, in which hydraulic cylinders according to the invention may be implemented. The working machine 10 may include a machine body 12 having a chassis 14. The machine body 12 may include ground engagement elements, such as a pair of rear wheels 16 and a pair of front wheels 18. It should be understood that, in addition to the wheels 16, 18, the machine body 12 may be provided with a pair of tracks or other structures to allow the working machine 10 to be transported on a work surface. The working machine 10 may also include an operator's cab 20 or other suitable facilities to accommodate an operator (not shown). The operator's cab 20 may include suitable controllers for driving the working machine 10, such as a steering wheel 22 and a gearshift lever 24. The operator's cab 20 may also have controllers for controlling the operation of the implements of the working machine 10, such as a joystick 26 mounted on an operator's seat 28, which allows the operator to interface with the control system (not shown) of the working machine 10.

[0021] The working machine 10 may include a loading bucket 30 located at a first end 32 of the machine body 12, and a suitable operating linkage 34 for operating the loading bucket 30, wherein the movement of the loading bucket 30 and the operating linkage 34 is controlled by a hydraulic cylinder (not shown). The working machine 10 may also include a pair of load-bearing supports or stabilizers 36 mounted near a second end 38 of the machine body 12. The load-bearing supports 36 may be hydraulically controlled by a hydraulic cylinder (not shown) in a relatively conventional manner to swing between a stored position and an extended position, in which the load-bearing supports 36 are in contact with the ground to stabilize the working machine 10 during operation of the implement.

[0022] The working machine 10 may also include a digging assembly 40, such as a backhoe mechanism, located at a second end 38 of the machine body 12. The backhoe mechanism 40 may include a suitable swing assembly 42 for allowing the backhoe mechanism 40 to swing about a pivot from one side of the machine body 12 to the other. The swing assembly 42 may be moved under the control of one or more hydraulic cylinders 44 and may be used to move the backhoe mechanism 40 from a digging position to a dumping position.

[0023] The backhoe mechanism 40 may include a cantilever 46 having a first end pivotally mounted near the machine body 12 for movement in a generally vertical plane. A lever 48 may have a first end pivotally mounted near a second end of the cantilever 46 for movement in the same generally vertical plane in which the cantilever 46 can move. A digging device in the form of a bucket 50 may be pivotally mounted at the second end of the lever 48 for pivotal movement in the same generally vertical plane in which the cantilever 46 and the lever 48 can move. The bucket 50 may be a relatively conventional backhoe bucket. The cantilever 46, lever 48, and bucket 50 may pivot under the control of hydraulic cylinders 52, 54, and 56, respectively.

[0024] Figure 2This is a partial cross-sectional side view of a hydraulic cylinder 54 for rod 48, illustrating the construction and manufacture of the hydraulic cylinder according to the invention. Although the hydraulic cylinder 54 is shown and described in detail herein, those skilled in the art will understand that hydraulic cylinders 52, 56, or any other hydraulic cylinders can be constructed in a similar manner. The hydraulic cylinder 54 may comprise a hollow cylindrical tube 100 having a first tube end 102 and a second tube end 104 opposite to the first tube end 102. The outer surface 106 of the cylindrical tube 100 may have a fixed or variable outer diameter, as discussed further below. The inner surface 108 may have an inner diameter sized to accommodate components disposed therein and manufacturing processes, as discussed further below.

[0025] The hydraulic cylinder 54 also includes a piston head 110 disposed within the cylindrical tube 100. The piston head 110 has an outer diameter smaller than the inner diameter of the tube to allow it to slide back and forth within the cylindrical tube 100 along the longitudinal axis 112 of the tube. An annular seal 116 surrounding the piston head 110 engages the inner surface 108 of the tube to fluidly isolate cavities on either side of the piston 110 from each other by preventing the flow of hydraulic fluid within the cylindrical tube 100 around the piston head 110. A piston rod 114, connected to one side of the piston head 110, extends out of the cylindrical tube 100 through the second end 104 of the tube. The piston rod 114 may be configured to be directly or indirectly coupled to a component of the working machine 10, such as rod 48, which will be actuated by the hydraulic cylinder 54 by extending and retracting the piston rod 114. Hydraulic fluid may be supplied to and discharged from the interior of the cylindrical tube 100 via a first fluid port 118 near the first end 102 of the tube. The first fluid port 118 can be selectively fluidly connected to a pressurized fluid source and a low-pressure reservoir via a control valve (not shown) to control the operation of the hydraulic cylinder 54, thereby extending and retracting the piston rod 114. The hydraulic cylinder 54 may also include a second fluid port (not shown) near the second end 104 of the tube to regulate the fluid flow rate and fluid pressure in the two chambers in a manner known in the art.

[0026] Cylinder head 120 closes the first end 102 of cylindrical tube 100, and cylinder head 122 closes the second end 104 of tube. Cylinder head 120 may include a cylindrical cap sealing portion 124 and a cylinder attachment portion 126. The cap sealing portion 124 is disposed within the first end 102 of tube and engages with the inner surface 108 of tube to retain cylinder head 120 and seal the first end 102 of tube, as further described below. If desired, a seal (not shown) may be constructed between the cap sealing portion 124 and the inner surface 108 of tube, as known in the art, to further prevent leakage of hydraulic fluid. Cylinder attachment portion 126 is disposed outside cylindrical tube 100 and configured to connect to a working machine 10, such as cantilever 46. With cylinder attachment portion 126 connected to cantilever 46 and piston rod 114 operably connected to rod 48, extension and retraction of piston rod 114 causes rod 48 to rotate relative to cantilever 46 about a pivot connection.

[0027] The cylinder head 122 may include a piston rod opening 128 for receiving a piston rod 114, allowing the piston rod 114 to slide therein. Seals 130, 132 may be provided to prevent hydraulic fluid leakage between the piston rod 114 and the piston rod opening 128. The cylinder head 122 is disposed within the cylindrical tube 100 at a second end 104. An outer surface 134 of the head engages with an inner surface 108 of the tube at the second end 104 to hold the cylinder head 122 in place therein. If desired, a seal 136 may be provided between the inner surface 108 of the tube and the outer surface 134 of the head to prevent hydraulic fluid leakage around the cylinder head 122.

[0028] The hydraulic cylinder 54 shown and described herein is a single-acting hydraulic cylinder with a single piston rod 114. Those skilled in the art will understand that the crimp retention according to the invention can be implemented in other types of hydraulic cylinders, such as double-acting hydraulic cylinders having piston rods 114 extending from either end 102, 104 of the cylindrical tube 100. Such double-acting hydraulic cylinders can be used in steering systems and other applications and include a second piston rod 114 connected to a piston head 110 and extending out of the first end 102 of the tube. The cylinder head 120 may be replaced by a second cylinder head 122 through which the second piston rod 114 extends, and the second cylinder head 122 is attached to the second end 104 of the tube in a manner similar to that described herein. The double-acting hydraulic cylinder may include a single fluid port 118, or have fluid ports 118 at either end 102, 104 as required in a particular embodiment. Other alternative configurations of single-acting and double-acting hydraulic cylinders implementing crimp retention according to the invention are conceived by the inventors.

[0029] Figure 3An enlarged view of the tube first end 102 and cylinder head 120 is shown before the components are secured together by a crimping force. The cap sealing portion 124 has a sealing portion outer surface 140, the outer diameter of which is smaller than the inner diameter of the tube at the tube first end 102 to allow insertion through the tube first end 102. The cap sealing portion 124 also includes a plurality of annular cap grooves 142 defined in the sealing portion outer surface 140. In the illustrated embodiment, the annular cap grooves 142 are recessed within the sealing portion outer surface 140 and have a constant groove width, such that the annular cap grooves 142 have a rectangular or square cross-section.

[0030] In an alternative embodiment, the annular cover groove 142 may have other cross-sectional shapes. Figures 3A to 3E This is an enlarged cross-sectional view of a portion of the cover sealing part 124, showing the geometry of several alternative groove structures. Figure 3A As shown Figure 3 The rectangular cover groove 142A shown and described. In Figure 3B In the process, the annular cover groove 142B may have a dovetail shape, wherein the width of the cover groove increases as the annular cover groove 142B extends inward from the outer surface 140 of the sealing portion. Figure 3C The annular cover groove 142C is shown closer to its inner edge. This allows more tube material of the cylindrical tube 100 to be positioned where it is subjected to hydraulic and structural forces that tend to push or pull the cylinder head 120 out of the cylindrical tube 100 after the first end 102 of the tube is pressed downward against the cover seal portion 124, as further described below. Figure 3D The annular cap groove 142D shown has an outward edge that slopes inward to guide the tube material toward the inward edge during the crimping process. Figure 3E It shows a similar Figure 3B The inner edge of the dovetail cap groove 142B and similar to Figure 3D The annular cover groove 142D has an inclined outer edge and an annular cover groove 142E. Other alternative cross-sectional shapes of the annular cover groove 142 can be envisioned to create the desired engagement between the inner surface 108 of the tube and the outer surface 140 of the sealing portion, as described below.

[0031] When the cap sealing portion 124 is inserted, the first end 102 of the tube can be crimped to engage the inner surface 108 of the tube with the outer surface 140 of the sealing portion. (Reference) Figure 4The crimping force can be applied to the outer surface 106 of the tube near the first end 102 of the tube using a suitable crimping device. In the illustrated embodiment, the crimping jaws 144 of the hydraulic crimping machine engage the outer surface 106 of the tube and apply a radial force to press the corresponding portion of the cylindrical tube 100 downward onto the cap sealing portion 124. As the crimping force compresses the cylindrical tube 100, the tube material at the inner surface 108 of the tube can be pressed into the annular cap groove 142. The crimping force can also create a crimping notch 146 in the outer surface 106 of the tube below the crimping jaws 144. Suitable materials may include steel, stainless steel, aluminum, or other materials that have sufficient ductility to undergo the deformation shown in the figure under the crimping force and sufficient strength to handle the forces encountered during the operation of the hydraulic cylinder 54 and to operate the hydraulic system. The tube material flows into the annular cap groove 142 to form an interference fit, preventing the cap sealing portion 124 from separating from the first end 102 of the tube. In some implementations, a hydraulic seal may be formed between the inner surface 108 of the pipe and the outer surface 140 of the sealing portion. In other embodiments, a separate sealing device, such as an O-ring (not shown), may be required to prevent hydraulic fluid leakage from the first end 102 of the pipe.

[0032] Figure 3 and 4 Further variations of the embodiments are anticipated and can be implemented in the hydraulic cylinder according to the invention. Figure 5 An embodiment is shown in which the portion of the cylindrical tube 100 near the first end 102 has a smaller outer diameter than the rest of the cylindrical tube 100. The reduced thickness of the cylindrical tube 100 in this region will facilitate deformation under applied compression force as described above.

[0033] Figure 6 Another alternative embodiment is shown, in which surfaces 108 and 140 are substantially reversed. A plurality of annular grooves 150 are defined in the inner surface 108 of the tube, while the annular cap groove 142 of the sealing portion outer surface 140 may omit the annular cap groove 142 of the aforementioned embodiment. When a pressing force compresses the cylindrical tube 100 at the first end 102 of the tube, the cap material near the sealing portion outer surface 140 will be pressed into the annular grooves 150 in a similar manner to that described above. Therefore, the cap material in this embodiment should have similar ductility to the tube material described above.

[0034] Figure 7Another alternative embodiment is shown, wherein both the inner surface 108 of the tube and the outer surface 140 of the sealing portion are configured to engage when a compression force is applied. The outer surface 140 of the sealing portion may include a plurality of annular cap grooves 142 as described above. The inner surface 108 of the tube may have a plurality of annular tube ribs 152 extending radially inward from the inner surface 108 near the first end 102 of the tube. The inner diameter of the annular tube ribs 152 is larger than the outer diameter of the sealing portion before a compression force is applied to allow the cap sealing portion 124 to be inserted. When the cap sealing portion 124 is inserted into the first end 102 of the tube, the annular cap grooves 142 align with the corresponding annular tube ribs 152. After alignment, a compression force is applied to force the annular tube ribs 152 radially inward into the corresponding annular cap grooves 142, thereby securing the cylinder head 120. In an alternative embodiment, the mechanism can be reversed. The inner surface 108 of the tube may have annular tube grooves 150 as described above, and the outer surface 140 of the sealing portion may have a plurality of radially outwardly extending annular cap ribs. The annular groove 150 and the annular cover rib can be aligned as described above, such that the annular groove 150 receives the annular cover rib when a pressing force is applied.

[0035] In addition to permanently fixing the cylinder head 120 to the cylindrical tube 100, or as an alternative, the cylinder head 122 can be fixed in a manner similar to that shown and described above. Figure 8 As shown, a plurality of annular head grooves 160 may be formed in the outer surface 134 of the head. When a pressing force is applied and a pressing notch 162 is formed, the tube material at the inner surface 108 of the tube can be pressed into the annular head grooves 160. The annular head grooves 160 are exemplary and can be implemented at the cylinder head 122 and the second end 104 of the cylindrical tube 100 as described above. Figure 3 -7 Any other combination of connecting elements for cylinder head 120 discussed herein, such as constant or increased head groove width, smaller tube outer diameter, annular tube groove, annular head or tube rib, etc.

[0036] Figure 9 Another alternative embodiment of the cylindrical tube 100 and cylinder head 120 is shown, which facilitates the insertion of the cap sealing portion 124 into the first end 102 of the tube and the crimping of the first end 102 of the cylindrical tube 100. The second end 104 of the tube and the cylinder head 122 can be constructed in a similar manner. In this embodiment, the cap sealing portion 124 can be tapered, such that the outer diameter of the sealing portion outer surface 140 decreases as the cap sealing portion 124 extends away from the cylinder attachment portion 126. The draft angle of the taper can be as shallow or as steep as required by a particular embodiment, and as... Figure 9The angle shown is approximately 2°. The first end 102 of the cylindrical tube may have a complementary conical portion 164 such that as the inner surface 108 extends from the interior of the cylindrical tube toward the first end 102, the inner diameter of the inner surface increases, and correspondingly, the wall thickness of the cylindrical tube decreases. The draft angle of the inner surface 108 may, as needed, be greater than, less than, or approximately equal to the draft angle of the cap seal portion 124 to ensure a secure and sealing fit between the components after a pressing force is applied.

[0037] Industrial applicability

[0038] Figure 10 An exemplary hydraulic cylinder manufacturing process 170 for a hydraulic cylinder 54 according to the present invention is shown. Manufacturing process 170 may begin at block 172 by forming annular grooves and / or annular ribs in surfaces 108, 134, and / or 140, depending on how the cylinder head 120 and cylinder head 122 will be attached to the cylindrical tube 100. Grooves or ribs may be formed in surfaces 108, 134, and 140 when the corresponding parts are formed, for example, during casting or extrusion. Alternatively, the grooves or ribs may be machined into the parts after initial manufacturing. At block 172, before, simultaneously with, or after the formation of the annular tube groove 150 or annular tube rib 152 in the inner surface 108 of the tube, control may be transferred to block 174, in which the outer diameter of the outer surface 106 of the tube decreases near the first end 102, the second end 104, or both. Similar to the annular groove 150 or the annular rib 152, the outer diameter of the tube can be reduced during the initial manufacturing process of the cylindrical tube 100, or it can be formed by machining the outer surface 106 of the tube after the cylindrical tube 100 has been cast or extruded.

[0039] Once the connection for the cylinder head 120 and / or cylinder head 122 is completed at blocks 172, 174, control can be transferred to block 176, in which the cylinder head 120 and / or cylinder head 122 are inserted into the corresponding tube ends 102, 104. As shown here, the inner diameter of the sealing portion is smaller than the inner diameter of the tube to facilitate the insertion of the cap seal portion 124. However, in an alternative embodiment, the inner diameter of the sealing portion may be slightly larger than the inner diameter of the tube to create an interference fit between the components. In such an embodiment, insertion at block 176 will require applying force to press-fit the cap seal portion 124 into the first tube end 102 of the cylindrical tube 100. Depending on the specific implementation, such as Figure 7As shown, insertion may further include aligning the corresponding annular cap groove 142 and annular tube rib 152. When the cylinder head 120 and / or cylinder head 122 is inserted and aligned, control may be transmitted to block 178, in which heat may be applied to the corresponding tube ends 102 and / or 104 to facilitate deformation of the cylindrical tube 100. Simultaneously or subsequently, control may be transmitted to block 180, in which crimping force is applied to the first tube end 102 and / or the second tube end 104 to secure the cylinder head 120 and / or cylinder head 122 to the cylindrical tube 100.

[0040] Compared to previously known hydraulic cylinders, the hydraulic cylinder according to the present invention can increase the reliability of component connections while reducing manufacturing time and cost. Depending on the usability requirements of the hydraulic cylinder, one or both of the cylinder head 120 and cylinder head 122 can be permanently attached to the cylindrical tube by the manufacturing process shown and described herein. This connection eliminates the need for equipment and process steps for machining cylinder threads and weld grooves into the components, welding the cylinder head 120 or cylinder head 122 to the cylindrical tube 100, and applying torque to screw the cylinder head 120 or cylinder head 122 into the corresponding tube ends 102, 104. It also eliminates the need and cost of separate connecting components such as retaining rings. Despite the cost and manufacturing reductions, the attachment mechanism according to the present invention provides sufficient strength to reliably retain the cylinder head 120 and cylinder head 122 in the tube ends 102, 104 without allowing hydraulic fluid to leak from the hydraulic cylinder 54.

[0041] While the foregoing text has described many different embodiments in detail, it should be understood that the legal scope of protection is defined by the wording of the claims set forth at the end of this patent. The detailed descriptions should be interpreted as exemplary only and do not describe every possible embodiment, as describing every possible embodiment would be impractical, if not impossible. Many alternative embodiments may be implemented using current technology or technology developed after the filing date of this patent, which will still fall within the scope of the claims defining the scope of protection.

[0042] It should also be understood that, unless a term is expressly defined herein, there is no intention to expressly or implicitly limit the meaning of that term beyond its ordinary or common meaning, and such term should not be construed as limiting the scope of any statement made in any part of this patent (other than the language of the claims). Any term recited herein in accordance with a single meaning as stated in the claims at the end of this patent is merely for clarity so as not to confuse the reader and is not intended to limit such claim terms to that single meaning by implication or otherwise.

Claims

1. A hydraulic cylinder (54), comprising: The cylindrical tube (100) has an inner surface (108), an outer surface (106), a first end (102), a second end (104) opposite to the first end (102), and a first fluid port (118) adjacent to the first end (102). The piston head (110) is arranged inside the cylindrical tube (100); A piston rod (114) is connected to the piston head (110) and extends outward from the cylindrical tube (100) through the second end (104) of the tube. A cylinder head (122) having a piston rod opening (128) that receives the piston rod (114) and allows the piston rod (114) to slide through it, wherein the cylinder head (122) is inserted into and engages with the second end (104) of the cylindrical tube (100) to retain the cylinder head (122) therein; and A cylinder head (120) has a cylindrical cap sealing portion (124) and a cylinder attachment portion (126), wherein the cap sealing portion (124) has a plurality of annular cap grooves (142, 142A, 142B, 142C, 142D, 142E) defined in the outer surface (140) of the sealing portion, wherein the cap sealing portion (124) is inserted into the first end (102) of the tube and adjacent to the outer surface (106) of the first end (102) of the tube. Pressed downward onto the cap sealing portion (124), such that the tube material of the cylindrical tube (100) at the inner surface (108) of the tube adjacent to the first end (102) of the tube is arranged in the plurality of annular cap grooves (142, 142A, 142B, 142C, 142D, 142E) to retain the cap sealing portion (124) within the first end (102) of the tube and seal the first end (102) of the cylindrical tube (100). The cylindrical tube (100) has a plurality of annular tube ribs (152) extending radially inward from the inner surface (108) of the tube adjacent to the first end (102) of the tube, wherein each of the plurality of annular tube ribs (152) is aligned with a corresponding one of the plurality of annular cover grooves (142) when the outer surface (106) of the tube is pressed down onto the cover seal portion (124), and each of the plurality of annular tube ribs (152) is arranged within the corresponding one of the plurality of annular cover grooves (142).

2. The hydraulic cylinder (54) according to claim 1, wherein the plurality of annular cover grooves (142, 142A) have a rectangular cross-section.

3. The hydraulic cylinder (54) according to claim 1, wherein, The width of each of the plurality of annular cover grooves (142B) increases as the plurality of annular cover grooves (142B) extend inward from the outer surface (140) of the sealing portion.

4. The hydraulic cylinder (54) according to claim 1, wherein, The outer surface (106) of the tube has a smaller outer diameter at the first end (102) of the tube adjacent to the cylindrical tube (100).

5. The hydraulic cylinder (54) according to claim 1, wherein, The inner surface (108) of the tube is tapered (164) such that the inner diameter of the tube increases as the inner surface (108) extends toward the first end (102) of the tube, and wherein the cap sealing portion (124) has a tapered sealing portion outer diameter such that the sealing portion outer diameter decreases as the cap sealing portion (124) extends from the cylinder attachment portion (126).

6. The hydraulic cylinder (54) according to claim 1, wherein, The cylinder head (122) has a plurality of annular head grooves (160) defined in the outer surface (134) of the head, wherein the cylinder head (122) is inserted into the second end (104) of the tube and the outer surface (106) of the tube adjacent to the second end (104) of the tube is pressed down onto the cylinder head (122) such that the tube material of the cylindrical tube (100) is disposed in the plurality of annular head grooves (160) on the inner surface (108) of the tube adjacent to the second end (104) of the tube to retain the cylinder head (122) within the second end (104) of the tube and seal the second end (104) of the cylindrical tube (100).

7. A method for manufacturing a hydraulic cylinder (54), comprising: Multiple annular cover grooves (142, 142A, 142B, 142C, 142D, 142E) are formed in the outer surface (140) of the sealing portion of the cover sealing portion (124) of the cylinder head (120). Insert the cover sealing part (124) into the first end (102) of the cylindrical tube (100) of the hydraulic cylinder (54); as well as The outer surface (106) of the cylindrical tube (100) adjacent to the first end (102) of the tube is pressed downward onto the cap sealing portion (124), such that the tube material of the cylindrical tube (100) is disposed in the plurality of annular cap grooves (142, 142A, 142B, 142C, 142D, 142E) at the inner surface (108) adjacent to the first end (102) of the tube, so as to retain the cap sealing portion (124) within the first end (102) of the tube and seal the first end (102) of the cylindrical tube (100); The method further includes: Multiple annular tube ribs (152) are formed, the annular tube ribs (152) extending radially inward from the inner surface (108) of the cylindrical tube (100) adjacent to the first end (102) of the tube; When the cap sealing portion (124) is inserted into the first end (102) of the tube, each of the plurality of annular tube ribs (152) is aligned with the corresponding one of the plurality of annular cap grooves (142), such that when the outer surface (106) of the tube is pressed down onto the cap sealing portion (124), each of the plurality of annular tube ribs (152) is disposed within the corresponding one of the plurality of annular cap grooves (142).

8. The method for manufacturing a hydraulic cylinder (54) according to claim 7, wherein the outer diameter of the cylindrical tube (100) adjacent to the first end (102) of the tube is reduced before pressing the outer surface (106) of the tube.

9. The method for manufacturing a hydraulic cylinder (54) according to claim 7, wherein, Forming the plurality of annular cover grooves (142, 142A) includes forming each of the plurality of annular cover grooves (142) having a rectangular cross-section.

10. The method for manufacturing a hydraulic cylinder (54) according to claim 7, wherein, Forming the plurality of annular cover grooves (142B) includes forming the plurality of annular cover grooves (142B) such that the width of each of the plurality of annular cover grooves (142B) increases as the plurality of annular cover grooves (142B) extend inward from the outer surface (140) of the sealing portion.

11. The method for manufacturing a hydraulic cylinder (54) according to claim 7, wherein heat is applied to the first end (102) of the cylindrical tube (100) before pressing it.

12. The method for manufacturing a hydraulic cylinder (54) according to claim 7, comprising: A plurality of annular head grooves (160) are formed on the outer surface (134) of the cylinder head (122), the cylinder head (122) having a piston rod opening (128) receiving a piston rod (114), the piston rod (114) extending from the second end (104) of the cylindrical tube (100) opposite to the first end (102) of the tube; Insert the cylinder head (122) into the second end (104) of the tube; and The outer surface (106) of the cylindrical tube (100) adjacent to the second end (104) of the tube is pressed downward onto the cylinder head (122), such that the tube material of the cylindrical tube (100) is disposed in the plurality of annular head grooves (160) at the inner surface (108) of the tube adjacent to the second end (104) of the tube, so as to retain the cylinder head (122) within the second end (104) of the tube and seal the second end (104) of the cylindrical tube (100).

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