Combined piston rod

Abstract

The combined piston rod comprises a rod core, a rod sleeve and a sealing ring, the rod core is provided with a thin rod section and a thick rod section which are coaxially and sequentially arranged, the thin rod section is detachably sleeved with the rod sleeve and sealed through the sealing ring, and the outer diameter of the thick rod section is larger than that of the thin rod section sleeved with the rod sleeve. And the oil leakage risk caused by heat treatment flaws can be reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of linear driving elements, in particular the technical field of piston rods. BACKGROUND

[0002] Both oil cylinders and air cylinders are common linear driving elements, which can convert the pressure energy of fluid (hydraulic oil or compressed air) into mechanical energy to achieve linear reciprocating motion or oscillation and drive various mechanical devices to complete specific work; the piston rod is an important part of the oil cylinder or air cylinder, which mainly transmits the reciprocating motion of the piston to external mechanical devices and bears loads such as thrust and tensile force during work.

[0003] Taking the oil cylinder as an example, since the cylinder body is usually made of steel, most factories will choose cast iron (such as HT250 gray cast iron) to integrally cast the piston rod, such as the centrifugal casting process for a piston rod and the centrifugal casting piston rod disclosed in CN116274928A, the processing method for an alloy cold-hard spheroidal graphite cast iron piston rod disclosed in CN101323014B, and the processing device for a cold-hard cast iron piston rod disclosed in CN117102407B, so as to avoid the oil cylinder from being blown up; in addition, in order to achieve the effect of "surface hardening and core toughness" of the piston rod, the factory will generally also perform high-frequency heat treatment and chrome plating polishing on the piston rod (the surface hardness can usually reach HRC35-40).

[0004] However, the piston rod integrally cast from cast iron is prone to surface cracking or small pits and other defects during high-frequency heat treatment; these defects will cause oil leakage during the operation of the machine, which needs to be solved urgently. SUMMARY

[0005] The purpose of the present application is to solve the problems in the prior art and provide a combined piston rod, which can reduce the risk of oil leakage caused by heat treatment defects.

[0006] To achieve the above-mentioned purpose, the present application provides a combined piston rod, which comprises a rod core, a rod sleeve and a sealing ring, the rod core has a thin rod section and a thick rod section arranged coaxially in sequence, the rod sleeve is detachably sleeved outside the thin rod section and is sealed by the sealing ring, and the outer diameter of the thick rod section is greater than that of the thin rod section sleeved with the rod sleeve.

[0007] As a preferred, the connection between the thin rod section and the thick rod section is further provided with a core body step, the outer diameters of the thin rod section, the core body step and the thick rod section are sequentially increased, the outer surface of the core body step is provided with a step ring groove, the rod sleeve has a sleeve body ring protrusion extending outward from the mouth and capable of covering outside the core body step, and the sealing ring is installed in the step ring groove and is extruded by the core body step and the sleeve body ring protrusion.

[0008] As preferred, the outer surface of the thick rod section is provided with a core ring groove, the end of the thick rod section away from the thin rod section is provided with a cavity connected to the thin rod section, and the end of the rod sleeve away from the thin rod section is provided with a sleeve body screw hole.

[0009] As preferred, the rod core is a cast iron core, and the rod sleeve is a steel sleeve.

[0010] As preferred, the outer surface of the rod sleeve is subjected to high-frequency heat treatment and chromium plating polishing.

[0011] As preferred, the outer surface of the thin rod section is provided with an external thread, the rod sleeve is threadedly connected outside the thin rod section through an internal thread located on the inner surface and matched with the external thread, and the thin rod section and the rod sleeve are further provided with a corresponding core body screw hole and a sleeve body through hole, and the thin rod section and the rod sleeve are connected through a bolt penetrating the sleeve body through hole and screwed into the core body screw hole.

[0012] As preferred, the first elastic mechanism has an elastic tendency to drive the bolt to be separated from the core body screw hole and the sleeve body through hole, and the second elastic mechanism has an elastic tendency to drive the rod core to be relatively away from the rod sleeve.

[0013] As preferred, the first elastic mechanism is a spring washer, and the second elastic mechanism includes a sleeve body push plate, a core body push plate, and a spring, the rod sleeve and the thin rod section are respectively provided with a sleeve body recess and a core body recess capable of accommodating the sleeve body push plate and the core body push plate, and the spring is arranged between the sleeve body push plate and the core body push plate.

[0014] As preferred, the side of the core body push plate facing the sleeve body push plate is rotatably connected with a base through a bearing, and the two ends of the spring are respectively fixed with the sleeve body push plate and the base.

[0015] As preferred, the rod sleeve and the sleeve body push plate can be clamped together through a clamping point and a clamping opening, and the rod sleeve is provided with a sleeve body insertion hole connected with the outside and the sleeve body recess.

[0016] The beneficial effects of the present application are: 1) detachable combination design, reducing maintenance cost: the rod core and the rod sleeve of the present application are detachably sleeved to replace the integrated piston rod, when one of the components has heat treatment defects, wear or damage, the specified component can be replaced alone without the need for overall scrapping (such as when the surface of the rod sleeve cracks, only the steel sleeve needs to be replaced, and the rod core can still be used), thereby greatly reducing the repair cost and the part loss rate. 2) Separate material collocation, optimize mechanical properties and heat treatment adaptability: the present application uses cast iron material (such as HT250 gray cast iron) for the rod core, and 45# steel material for the rod sleeve, so that on the one hand, the good casting performance of cast iron material and the compatibility with the cylinder body material can be used to avoid the oil cylinder from being pulled out, and on the other hand, the excellent heat treatment performance of 45# steel material can be used to collocate chromium plating polishing to effectively improve the surface hardness of the rod sleeve, so that the piston rod can meet the strength requirement of bearing alternating load, and improve the surface wear resistance and oil leakage resistance; 3) Multiple sealing and connecting structure, improve reliability: in the present application, the core body step and the sleeve ring convex part can extrude the sealing ring between the rod core and the rod sleeve to form an effective sealing line to prevent hydraulic oil or compressed air leakage; in addition, the rod core and the rod sleeve can be preliminarily connected through the cooperation of the outer thread of the thin rod segment and the inner thread of the rod sleeve, and the bolt connection through the through hole of the sleeve body and the screw hole of the core body is used for reinforcement, which can effectively prevent the separation of the rod core and the rod sleeve under high frequency vibration or alternating load; 4) Elastic anti-loosening mechanism, enhance dynamic stability: the present application can prevent the bolt from loosening under vibration and impact load by using the elastic deformation of the first elastic mechanism (spring washer), and can further improve the assembly stability by using the second elastic mechanism (spring push plate structure) to apply a reverse elastic force to the rod core and the rod sleeve to offset the axial displacement trend of the thread between the rod sleeve and the thin rod segment.

[0017] The features and advantages of the present application will be described in detail in conjunction with the embodiments and the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a sectional view of example one; Figure 2 is a sectional view of the rod core of example one; Figure 3 is a sectional view of the rod sleeve of example one; Figure 4 is a left view of the rod sleeve of example one; Figure 5 is a sectional view of example two; Figure 6 is an enlarged view of A of Figure 5

[0019] ​In the figure: 1-rod core, 11-thin rod section, 12-thick rod section, 13-core step, 14-step ring groove, 15-core ring groove, 16-core ring groove, 17-cavity, 18-core cavity, 2-rod sleeve, 21-sleeve ring convex, 22-sleeve through hole, 23-sleeve screw hole, 24-sleeve cavity, 25-clamping point, 26-sleeve insertion hole, 3-sealing ring, 4-bolt, 5-first elastic mechanism, 6-second elastic mechanism, 61-sleeve push plate, 611-clamp, 62-core push plate, 63-spring, 64-base, 65-bearing. DETAILED DESCRIPTION

[0020] Example one: Reference Figures 1 to 4 In this embodiment, the combined piston rod comprises a rod core 1, a rod sleeve 2 and a sealing ring 3, the rod core 1 has a thin rod section 11 and a thick rod section 12 arranged coaxially in sequence, the rod sleeve 2 is detachably sleeved outside the thin rod section 11 and is sealed by the sealing ring 3, and the outer diameter of the thick rod section 12 is larger than that of the thin rod section 11 sleeved with the rod sleeve 2; since the rod core 1 and the rod sleeve 2 are detachable, even if one of the components has a defect, it can be replaced individually.

[0021] The connection between the thin rod section 11 and the thick rod section 12 is also provided with a core step 13, the outer diameters of the thin rod section 11, the core step 13 and the thick rod section 12 increase in sequence, the outer surface of the core step 13 is provided with a step ring groove 14, the rod sleeve 2 has a sleeve ring convex 21 extending outward from the mouth and can be wrapped outside the core step 13, and the sealing ring 3 is loaded into the step ring groove 14 and is extruded by the core step 13 and the sleeve ring convex 21.

[0022] The outer surface of the thick rod section 12 is provided with a core ring groove 16, the end of the thick rod section 12 away from the thin rod section 11 is provided with a cavity 17 connected to the thin rod section 11, and the end of the rod sleeve 2 away from the thin rod section 11 is provided with a sleeve screw hole 23; wherein the core ring groove 16 is used to load a piston ring to realize the sealing between the piston rod and the cylinder; the cavity 17 is a hollow part left in advance, which can be loaded with a quick cylinder according to the actual needs of the user, so as to flexibly expand the application scene of the piston rod and adapt to different working condition requirements; the sleeve screw hole 23 is a lifting structure for facilitating the lifting of the piston rod, which can improve the assembly efficiency.

[0023] The rod core 1 is a cast iron core, and the rod sleeve 2 is a steel sleeve; specifically, the steel sleeve can be made of 45# steel material.

[0024] The outer surface of the sleeve 2 is subjected to high-frequency heat treatment and chrome plating and polishing (the chrome plating layer is controlled at 0.05mm, and polished after plating), and the hardness is controlled at HRC50-55. In other words, this embodiment adopts a split design for the piston rod, replacing the part that requires high-frequency heat treatment and is prone to heat treatment defects with 45# steel (45# steel has excellent heat treatment performance), while the part that needs to contact the cylinder body is still retained as a cast iron part, thereby greatly reducing the probability of product scrap due to high-frequency heat treatment.

[0025] The outer surface of the thin rod segment 11 is provided with external threads. The rod sleeve 2 is threaded to the outside of the thin rod segment 11 through an internal thread located on the inner surface and cooperating with the external threads. The thin rod segment 11 and the rod sleeve 2 are also provided with corresponding core screw holes 15 and sleeve through holes 22. The thin rod segment 11 and the rod sleeve 2 are connected by a bolt 4 that passes through the sleeve through hole 22 and is screwed into the core screw hole 15. This double connection design can effectively prevent the rod core 1 and the rod sleeve 2 from separating prematurely.

[0026] It also includes a first elastic mechanism 5, which has an elastic tendency to drive the bolt 4 to disengage from the core screw hole 15 and the sleeve through hole 22.

[0027] The first elastic mechanism 5 is a spring washer; wherein, the spring washer can use the friction and mechanical tension generated by its own elastic deformation to prevent the bolt 4 from loosening under vibration, impact or alternating load.

[0028] Example 2: See Figures 5 to 6 This embodiment also includes a second elastic mechanism 6, which has an elastic tendency to drive the core 1 and the sleeve 2 away from each other.

[0029] The second elastic mechanism 6 includes a sleeve push plate 61, a core push plate 62, and a spring 63. A sleeve cavity 24 and a core cavity 18, which can accommodate the sleeve push plate 61 and the core push plate 62, are respectively provided between the sleeve 2 and the thin rod segment 11. The spring 63 is disposed between the sleeve push plate 61 and the core push plate 62. The spring 63 can provide an elastic tendency for the sleeve 2 and the rod core 1 to move away from each other through the sleeve push plate 61 and the core push plate 62, thereby preventing the thread from loosening between the sleeve 2 and the thin rod segment 11.

[0030] The core push plate 62 is rotatably connected to the base 64 via a bearing 65 on the side facing the sleeve push plate 61. The two ends of the spring 63 are fixed to the sleeve push plate 61 and the base 64 respectively. The relative rotatable design between the core push plate 62 and the base 64 can reduce the resistance of the second elastic mechanism 6 to the threaded turning between the sleeve 2 and the thin rod segment 11, thereby ensuring the compatibility of installation convenience and anti-loosening effect.

[0031] The rod sleeve 2 and the sleeve body push plate 61 can also be clamped together through the clamping point 25 and the clamping hole 611. The rod sleeve 2 is provided with a sleeve insertion hole 26 which is in communication with the cavity 24 and the outside. During installation, the sleeve body push plate 61 can be clamped into the sleeve cavity 24 through the clamping point 25 and the clamping hole 611, so as to pre-position the second elastic mechanism 6 (shorten the assembly time), and then the rod sleeve 2 is gradually screwed onto the thin rod section 11. When the second elastic mechanism 6 needs to be taken out, the sleeve body push plate 61 can also be pushed out of the sleeve cavity 24 by using a long rod inserted into the sleeve insertion hole 26.

[0032] The other is the same as the first embodiment.

[0033] The above embodiments are illustrative of the present application, but not limiting of the present application. Any simple transformation of the present application belongs to the protection scope of the present application.

Claims

1. A combined piston rod, characterized in that: The rod includes a core (1), a sleeve (2), and a sealing ring (3). The core (1) has a thin rod segment (11) and a thick rod segment (12) arranged coaxially in sequence. The sleeve (2) is detachably fitted outside the thin rod segment (11) and sealed by the sealing ring (3). The outer diameter of the thick rod segment (12) is larger than the outer diameter of the thin rod segment (11) fitted with the sleeve (2).

2. The combined piston rod as described in claim 1, characterized in that: The connection between the thin rod segment (11) and the thick rod segment (12) is also provided with a core step (13). The outer diameters of the thin rod segment (11), the core step (13) and the thick rod segment (12) increase sequentially. The outer surface of the core step (13) is provided with a step ring groove (14). The rod sleeve (2) has a sleeve ring protrusion (21) extending outward from the opening edge and covering the core step (13). The sealing ring (3) is inserted into the step ring groove (14) and is squeezed by the core step (13) and the sleeve ring protrusion (21).

3. The combined piston rod as described in claim 1, characterized in that: The outer surface of the thick rod section (12) is provided with a core ring groove (16), and the end of the thick rod section (12) away from the thin rod section (11) is provided with a cavity (17) that connects to the thin rod section (11). The end of the rod sleeve (2) away from the thin rod section (11) is provided with a sleeve screw hole (23).

4. The combined piston rod as described in claim 1, characterized in that: The rod core (1) is a cast iron core, and the rod sleeve (2) is a steel sleeve.

5. The combined piston rod as described in claim 4, characterized in that: The outer surface of the sleeve (2) is subjected to high-frequency heat treatment and chrome plating and polishing.

6. The combined piston rod as described in any one of claims 1 to 5, characterized in that: The outer surface of the thin rod segment (11) is provided with external threads. The rod sleeve (2) is threaded to the outside of the thin rod segment (11) through an internal thread located on the inner surface and cooperating with the external threads. The thin rod segment (11) and the rod sleeve (2) are also provided with corresponding core screw holes (15) and sleeve through holes (22). The thin rod segment (11) and the rod sleeve (2) are connected by a bolt (4) that passes through the sleeve through hole (22) and is screwed into the core screw hole (15).

7. The combined piston rod as described in claim 6, characterized in that: It also includes a first elastic mechanism (5) and a second elastic mechanism (6), wherein the first elastic mechanism (5) has an elastic tendency to drive the bolt (4) to disengage from the core screw hole (15) and the sleeve through hole (22), and the second elastic mechanism (6) has an elastic tendency to drive the rod core (1) to move away from the rod sleeve (2) relatively.

8. The combined piston rod as described in claim 7, characterized in that: The first elastic mechanism (5) is a spring washer, and the second elastic mechanism (6) includes a sleeve push plate (61), a core push plate (62) and a spring (63). The sleeve (2) and the thin rod section (11) are respectively provided with a sleeve cavity (24) and a core cavity (18) that can accommodate the sleeve push plate (61) and the core push plate (62). The spring (63) is disposed between the sleeve push plate (61) and the core push plate (62).

9. The combined piston rod as described in claim 8, characterized in that: The core push plate (62) facing the sleeve push plate (61) is rotatably connected to the base (64) via a bearing (65), and the two ends of the spring (63) are fixed to the sleeve push plate (61) and the base (64) respectively.

10. The combined piston rod as described in claim 8, characterized in that: The rod sleeve (2) and the sleeve push plate (61) can be engaged together by a locking point (25) and a locking slot (611). The rod sleeve (2) is provided with a sleeve insertion hole (26) that connects the outside world and the sleeve cavity (24).

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