A fixed-axis straight-line traveling vacuum cylinder

Abstract

The present invention relates to the technical field of vacuum cylinders, and discloses a fixed-axis linear-motion vacuum cylinder, which includes a cylinder body. A second cylindrical cavity is provided inside the cylinder body, and a first cylindrical cavity is provided at the bottom of the second cylindrical cavity. A step is arranged between the first cylindrical cavity and the second cylindrical cavity. A piston is coaxially arranged on the cylinder body. A piston head is installed at the top of the piston, and the piston head moves up and down along the second cylindrical cavity. The piston is a hollow structure with its upper and lower ends communicating with each other, and an opening communicating with the piston is provided at the top of the piston head. An air outlet is provided at the top side of the second cylindrical cavity to communicate the inside of the piston with the inside of the cylinder body. The other end of the piston extends from the first cylindrical cavity to the outside of the cylinder body. A shaft cylinder is coaxially connected to the bottom of the cylinder body, and the shaft cylinder is coaxially arranged with the piston. At least one set of ball holes is provided on the inner surface of the shaft sleeve. In the present invention, the piston is limited by the balls and the limiting grooves and can only be telescoped but not rotated, so that the piston is circumferentially fixed and can only perform axial linear motion.

Description

Technical Field

[0001] The present invention relates to the technical field of vacuum cylinders, and specifically to a fixed-axis linear-moving vacuum cylinder. Background Art

[0002] A cylinder is a mechanism that converts the pressure of compressed air into mechanical energy through pneumatic transmission. The piston of the cylinder realizes reciprocating motion under the push of the piston head. The piston head can rotate in the cylinder block. Therefore, while the cylinder is reciprocating, it is difficult to fix the circumferential position of the piston. After long-term use, the position of the piston will deflect. For this reason, we propose a fixed-axis linear-moving vacuum cylinder. Summary of the Invention

[0003] In view of the deficiencies of the existing vacuum cylinders, the present invention provides a fixed-axis linear-moving vacuum cylinder, which has the advantage that the piston cannot rotate, and solves the problems raised in the above background art.

[0004] The present invention provides the following technical solutions:

[0005] Design a fixed-axis linear-moving vacuum cylinder, including a cylinder block. A second cylindrical cavity is provided inside the cylinder block. The bottom of the second cylindrical cavity is provided with a first cylindrical cavity. The first cylindrical cavity and the second cylindrical cavity are stepped. A piston is coaxially arranged on the cylinder block. A piston head is installed on the top of the piston. The piston head moves up and down along the second cylindrical cavity. It is characterized in that the piston is a hollow structure with the upper and lower ends communicating with each other, and an opening communicating with the piston is opened at the top of the piston head. An air outlet is opened at the top of the side of the second cylindrical cavity to connect the inside of the piston and the inside of the cylinder block;

[0006] The other end of the piston extends from the first cylindrical cavity to the outside of the cylinder block. A shaft cylinder is coaxially connected to the bottom of the cylinder block. The shaft cylinder and the piston are coaxially arranged. A shaft sleeve is fixedly installed inside the shaft cylinder. At least one set of ball holes is provided on the inner surface of the shaft sleeve. The number of ball holes in each group is A, A≥1, and the ball holes are arranged at intervals along the axis direction of the cylinder block. A ball is provided in each of the ball holes, and the ball extends into the shaft sleeve;

[0007] Limiting grooves corresponding to the ball holes in number and position are provided on the side surface of the piston. Each group of balls is placed in the limiting grooves; An air suction interface is provided on the cylinder block at the first cylindrical cavity;

[0008] A sealing end cover is installed on the top of the cylinder block. The top of the piston is inserted into the piston head and the two are threadedly connected. A flange is provided on the inner wall of the cylinder block between the shaft cylinder and the first cylindrical cavity. Springs are provided in the first cylindrical cavity and the second cylindrical cavity. The springs are sleeved on the piston. The two ends of the springs are respectively in contact with the flange and the piston head.

[0009] Preferably, a negative pressure device is connected to the air suction interface through a pipeline.

[0010] Preferably, a vacuum suction cup is provided at the bottom of the piston. The top of the vacuum suction cup is mounted on the mounting head. The mounting head is of a hollow structure and is threadedly connected inside the bottom end of the piston. A filter screen is installed inside the vacuum suction cup.

[0011] Preferably, an interference fit and glue fixation are provided between the bushing and the barrel.

[0012] Preferably, the diameter of the opening is larger than the diameter of the air outlet, so that the air intake of the opening is greater than the gas flow rate of the air outlet.

[0013] Compared with the existing vacuum cylinder, when the present invention is in use, only a negative pressure device needs to be connected to the suction interface, and there is no need to exchange air at both ends of the cylinder body. At the same time, the piston is limited by the ball and the limiting groove and can only move axially and cannot rotate, so that the piston is circumferentially fixed and can only perform axial linear motion. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the piston descending of the present invention;

[0015] Figure 2 It is a schematic diagram of the piston lifting of the present invention;

[0016] Figure 3 It is a schematic diagram of the piston of the present invention structure retracted to the top of the cylinder body.

[0017] In the figure: cylinder body 1, piston head 2, sealed end cover 3, air outlet 4, suction interface 5, ball 6, limiting groove 7, bushing 8, piston 9, mounting head 10, barrel 11, first cylindrical cavity 12, second cylindrical cavity 13, spring 14, flange 15, ball hole 16, opening 17, vacuum suction cup 18. DETAILED DESCRIPTION OF THE INVENTION

[0018] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

[0019] Please refer to Figures 1-3 , a fixed-axis linear travel vacuum cylinder, including a cylinder body 1. A second cylindrical cavity 13 is provided inside the cylinder body 1. A first cylindrical cavity 12 is provided at the bottom of the second cylindrical cavity 13. A step is provided between the first cylindrical cavity 12 and the second cylindrical cavity 13. A piston 9 is coaxially provided in the cylinder body 1. A piston head 2 is mounted on the top of the piston 9. The piston head 2 moves up and down along the second cylindrical cavity 13. The top of the piston 9 is inserted into the piston head 2 and the two are threadedly connected;

[0020] The piston 9 has a hollow structure with its upper and lower ends communicating with each other, and an opening 17 communicating with the piston 9 is provided at the top of the piston head 2. As Figure 1 shown, the space between the piston head 2 and the top of the cylinder block 1 is the cavity A. An air outlet 4 is provided at the top side of the second cylindrical cavity 13 to connect the inside of the piston 9 with the inside of the cylinder block 1;

[0021] The other end of the piston 9 extends from the first cylindrical cavity 12 to the outside of the cylinder block 1. A shaft cylinder 11 is coaxially connected to the bottom of the cylinder block 1. The shaft cylinder 11 and the piston 9 are coaxially arranged. A shaft sleeve 8 is fixedly installed in the shaft cylinder 11. At least one set of ball holes 16 is provided on the inner surface of the shaft sleeve 8. The number of each set of ball holes 16 is A, A≥1, and the ball holes 16 are arranged at intervals along the axis direction of the cylinder block 1. A ball 6 is provided in each of the ball holes 16, and the ball 6 extends into the shaft sleeve 8; Limiting grooves 7 corresponding to the ball holes 16 in number and position are provided on the side surface of the piston 9, and each set of balls 6 is placed in the limiting grooves 7.

[0022] When the piston 9 reciprocates, the piston 9 is supported by the shaft sleeve 8. The contact between the ball 6 and the piston 9 is a point contact, and the ball can roll in the ball hole 16, so that the friction between the piston 9 and the ball becomes smaller, and it can be used for a long time without wear. Moreover, when the piston 9 is subjected to a circumferential deflection force, the ball is limited in the limiting groove 7, so that the circumferential direction of the piston 9 is limited. Therefore, the piston 9 can only reciprocate along the axis of the cylinder block 1;

[0023] As Figure 1 shown, an air suction interface 5 is provided on the cylinder block 1 at the first cylindrical cavity 12. The specific use process is as follows: The air suction interface 5 is connected to a negative pressure device, such as a vacuum pump, through a pipeline. When the air suction interface 5 sucks air outwards, it should be noted that the diameter of the opening 17 is larger than the diameter of the air outlet 4, so that the air intake of the opening 17 is greater than the gas flow rate of the air outlet 4. External air enters from the piston 9, resulting in a higher pressure in the cavity A than in the first cylindrical cavity 12 and the second cylindrical cavity 13. At this time, the piston 9 moves downward under the drive of the pressure in the cavity A;

[0024] A vacuum suction cup 18 is provided at the bottom of the piston 9. A filter screen is installed in the vacuum suction cup 18. The top of the vacuum suction cup 18 is installed on the mounting head 10. The mounting head 10 has a hollow structure and is threadedly connected to the inside of the bottom end of the piston 9. When the vacuum suction cup 18 reaches the object to be grasped (such as Figure 2 and Figure 3 the place pointed by the arrow B in), as the air in the cylinder block 1 is gradually pumped out, a negative pressure is formed in the vacuum suction cup 18 to suck the object. At this time, the bottom of the vacuum suction cup is sealed by the object. At this time, the gas in the cavity A flows out through the air outlet 4 and is sucked away by the air suction interface 5, so that the air pressure in the cavity A is less than the external atmospheric pressure, causing the piston 9 to rise, thereby driving the object to rise, thereby driving the object to rise.

[0025] Specifically, when the present invention is in use, since there is a clearance fit between the piston 9 and the bush 8, when the suction interface 5 stops sucking air, air continuously enters through the gap between the piston 9 and the bush 8 (it should be emphasized that the air suction volume of the suction interface 5 is much larger than the air intake volume through the gap). After the object is lifted to the preset position, the negative pressure device stops at this time, and the outside air gradually enters the cylinder through the gap. When the pressure difference between the inside and outside of the cylinder reaches a certain value, the object automatically falls off. That is, the pressure in the cavity A is greater than the pressure in the chamber 13, and the piston head is pressed downward. The vacuum chuck holds the object to be transported, and the closed air enters the vacuum cylinder. The vacuum degree in the inner cavity of the vacuum cylinder is vc. Under the action of the atmospheric pressure, the piston head, the vacuum chuck, and the object to be transported move upward. The upward lifting force of the vacuum cylinder = 1 / 4π × vacuum degree vc × dd. The vacuum pump stops sucking out air. Since there is a clearance fit between the piston head and the bush, the atmosphere flows into the inner cavity of the vacuum cylinder through the gap, and the pressure in the inner cavity of the vacuum cylinder gradually approaches the outside atmospheric pressure. The piston head and the vacuum chuck are held at a high position by the spring, and the object to be transported falls off, completing a cycle.

[0026] Wherein, a sealing end cover 3 is installed at the top of the cylinder block 1.

[0027] As Figure 1 shown, a flange 15 is provided on the inner wall of the cylinder block 1 between the shaft cylinder 11 and the first cylindrical cavity 12. Springs 14 are provided in the first cylindrical cavity 12 and the second cylindrical cavity 13. The springs 14 are sleeved on the piston 9, and the two ends of the springs 14 are respectively in contact with the flange 15 and the piston head 2. The provided springs 14 can ensure the stable movement of the piston 9, and at the same time, it can also allow outside air to enter the cylinder through the gap between the piston 9 and the bush 8.

[0028] Wherein, there is an interference fit and glue fixation between the bush 8 and the shaft cylinder 11.

[0029] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A fixed-axis straight-line traveling vacuum cylinder, comprising a cylinder block. A second cylindrical cavity is provided inside the cylinder block. A first cylindrical cavity is provided at the bottom of the second cylindrical cavity. A step is provided between the first cylindrical cavity and the second cylindrical cavity. A piston is coaxially provided on the cylinder block. A piston head is installed at the top of the piston. The piston head moves up and down along the second cylindrical cavity. It is characterized in that, The piston is a hollow structure with its upper and lower ends communicating with each other. An opening communicating with the piston is provided at the top of the piston head, and an air outlet is provided at the top of the piston side, so that the inside of the piston communicates with the inside of the cylinder block. The other end of the piston extends from the first cylindrical cavity to the outside of the cylinder block. A shaft cylinder is coaxially connected to the bottom of the cylinder block. The shaft cylinder and the piston are coaxially arranged. A shaft sleeve is fixedly installed in the shaft cylinder. At least one set of ball holes is provided on the inner surface of the shaft sleeve. The number of ball holes in each set is A, A≥1, and the ball holes are arranged at intervals along the axis direction of the cylinder block. A ball is provided in each of the ball holes, and the ball extends into the shaft sleeve. Limit grooves corresponding to the ball holes in number and position are provided on the side surface of the piston. Each set of balls is placed in the limit groove. An air inlet interface is provided on the cylinder block at the first cylindrical cavity. A sealing end cover is installed on the top of the cylinder block. The top of the piston is inserted into the piston head and the two are threadedly connected. A flange is provided on the inner wall of the cylinder block between the shaft cylinder and the first cylindrical cavity. Springs are provided in the first cylindrical cavity and the second cylindrical cavity. The springs are sleeved on the piston. The two ends of the springs are respectively in contact with the flange and the piston head. A negative pressure device is connected through a pipeline in the air inlet interface. A vacuum suction cup is provided at the bottom of the piston. The top of the vacuum suction cup is installed on the mounting head. The mounting head is a hollow structure and is threadedly connected to the inside of the bottom end of the piston. A filter screen is installed in the vacuum suction cup. When the air inlet interface sucks air outwards, the outside air enters from the piston, resulting in a higher pressure in the cavity than in the first cylindrical cavity and the second cylindrical cavity. At this time, the piston moves downward under the drive of the pressure in the cavity. When the air inlet interface stops sucking air, air continuously enters through the gap between the piston and the shaft sleeve. After the object is lifted to the preset position, at this time the negative pressure device stops, and the outside air gradually enters the cylinder block through the gap. The pressure in the cavity is greater than the pressure in the second cylindrical cavity, and the piston head is pressed down to move, and the object automatically falls off.

2. The fixed-axis straight-line traveling vacuum cylinder according to claim 1, characterized in that: The shaft sleeve and the shaft cylinder are in interference fit and fixed with glue.

3. The fixed-axis straight-line traveling vacuum cylinder according to claim 1, characterized in that: The diameter of the opening is larger than the diameter of the air outlet, so that the air intake of the opening is greater than the gas flow rate of the air outlet.

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