EA044923B1 - THREE-POSITION POWER PNEUMATIC OR HYDRAULIC CYLINDER - Google Patents

Description

Field of technology

The invention relates to volumetric pneumatic or hydraulic drives, specifically to devices of pneumatic (hydraulic) cylinders and can be used in robotic production lines, drives of mechanisms for various purposes, including in vehicle transmissions.

Prior Art

For example, a hydraulic drive for displacing the synchronizer is known (Patent RU2545543C2). The drive contains a cylinder and a piston configured to move inside the cylinder, separating the first and second chambers. The volume of the first chamber is smallest when the drive is in the first engagement position, and the volume of the second chamber is smallest when the drive is in the second engagement position. The piston also limits the third chamber in the cylinder, the volume of which is smallest when the drive is in the neutral position.

This drive is characterized by technological complexity, in particular, its performance directly depends on the accuracy of creating pressure in a particular chamber.

A three-position hydraulic cylinder is known (Patent RU2079007C1), containing a housing with windows for connecting to the load and supplying working fluid, in the cavity of which, closed by covers, there is a piston with a bore and plungers interacting with it and with the covers, characterized in that the plungers are located in the piston bore , which is equipped with stops that limit their movement.

A finger placed perpendicular to the longitudinal axis of the body is used as a working element that interacts with the load.

The disadvantage of this design is the impossibility of bringing the working element into the ends of the housing.

A pneumatic three-position cylinder (Patent HU187364B) was selected as a prototype, consisting of a body with end caps, two pistons, a rod, and channels for supplying the working medium. The pistons divide the internal space of the cylinder into three chambers, and each piston is made with the possibility of limited movement along the rod due to the central projection separating the pistons and peripheral projections on the rod, and limited movement inside the housing due to the projections formed on the inner surface of the housing. A thrust element is fixed to the rod between the two pistons, on which the inlet hole of the channel is located for supplying the working medium (air) into the chamber between the pistons.

The disadvantages of the known prototype device include the following design features:

Large dimensions due to the presence of an upper end cap.

There is no possibility of designing with additional rod exits from one of the end surfaces of the cylinder and, for example, a perpendicularly mounted pin.

The end surface of the protrusion (bushing) on the rod (in the working fluid supply area) acts as a piston and, therefore, negatively affects any movement of the rod, that is, to set the rod to medium or neutral, an additional amount of energy (pressure) of the working medium will be required.

Due to the possible pressure difference when the rod reaches the middle position, the so-called rod overrun of the middle position with subsequent return (occupation) of the middle position is possible. This factor is negative in devices where, according to the functionality of the work, this should not be the case.

The centering of the rod is ensured by its contacts with the covers and pistons, which, with significant force loads on the rod, can negatively affect the durability of the uninterrupted operation of the device. The alignment in the sealing areas looks questionable, to say the least. The HU187364B patent provides for increased seating dimensions of the pistons, due to which the rod is centered, and this increases the dimensions of the device, its weight and the materials consumed.

A more complex manufacturing design is used, for example, the restrictive protrusion in the middle part of the bushing must have a strictly defined fit relative to the outlet hole for the working medium, or have a clearly complex configuration with a system of grooves and holes, while ensuring strength impact characteristics; the use of retaining rings also complicates the design; An additional top cover is used, which must be secured and sealed.

Carrying out the invention

The objective of the invention was to create a device without the above disadvantages. The technical result is to simplify the design and increase the reliability, speed and accuracy of the device.

This problem is solved by a three-position pneumatic or hydraulic cylinder, consisting of a housing with end caps (walls), two pistons, a rod, channels for supplying the working medium, and each piston is made with the possibility of limited movement along the rod due to the central protrusion separating the pistons and peripheral protrusions on rod, and limited movement inside the body, in which, according to the proposal, the central protrusion is made in the form of a bushing, and on the inner surface of the body there is an annular protrusion, while the bushing and the protrusion form a sealed movable joint of the shaft-hole type. In essence, the proposed solution leads to the formation of four chambers inside the housing, formed by end caps (walls), two pistons and a partition formed by a sleeve and an annular protrusion.

A projection is any part, such as a bushing, part of a housing or a rod, that limits the movement of the pistons.

Embodiment of the invention

Two preferred embodiments of the invention are proposed, determined by the implementation of channels for supplying the working medium.

In the first preferred embodiment, the channels for supplying the working medium are designed as follows: separate channels into the chambers formed by each of the pistons and the corresponding end (end cover) of the housing, and a common channel into the chambers formed by each of the pistons and the central protrusion and bushing.

In the second preferred embodiment, the channels for supplying the working medium are designed as follows: separate channels into the chambers formed by each of the pistons and the central protrusion and bushing, the end of the housing, and a common channel into the chambers formed by each of the pistons and the corresponding end (end cover) of the housing.

For all implementation options, an addition is possible - securing at least one pin to interact with the load, placed at an angle to the axis of the rod in the bore of the annular protrusion.

It is possible to implement a device in which only the above element - a finger - is provided to interact with the load. In principle, it is possible to implement a design with one or two rod outputs, with one or more pins in various combinations determined by the specific purpose of the device. It is also possible to rotate the bushing with the pin sectorally around the axis of the bushing.

The invention is illustrated by graphic materials - drawings and photographs of a prototype.

In fig. 1 shows a longitudinal section of the cylinder in the first preferred embodiment, central (middle) position.

In fig. 2 shows a longitudinal section of the cylinder in the first preferred embodiment, extreme right position.

In fig. 3 and 4 show a longitudinal section of the cylinder in the second preferred embodiment, central (middle) position with different designs of channels for supplying the working medium.

In fig. 5 shows a longitudinal section of the cylinder in the second preferred embodiment, extreme right position.

The three-position cylinder consists of a body 1 in which a rod is installed, the central part of which is a cylindrical sleeve 2 with two ledges for pistons 3 and 4, which have free movement, both inside the cylindrical part of the body 1 and on the sleeve 2, two side covers 5 and 6, the end elements of the rod 7, 8 and the side pin 9. Structurally, it is advisable to make the rod from several rigidly connected parts: a sleeve 2 made of a material with low sliding friction, the end parts 7, 8 with peripheral protrusions and a side pin 9. The device contains also channels for supplying the working medium (compressed air or liquid) A, B and C.

In the first preferred embodiment (Figs. 1 and 2), separate channels A and C into the chambers formed by each of the pistons 3, 4 and the corresponding end of the housing (covers 5 and 6) can be made in the housing and covers 5 and 6. General channel B into the chambers formed by each of the pistons 3, 4 and the central protrusion and sleeve 2 - in the protrusion of the housing 1.

In the second preferred embodiment (Fig. 3, 4, 5), separate channels A and C into the chambers formed by each of the pistons and the central protrusion and sleeve by the end of the housing are made in the protrusion of the housing 1, and the common channel B - into the chambers formed by each of pistons 3, 4 and the corresponding end (end caps 5, 6) can be made in the wall of the housing 1 (Fig. 3 and 5), or in the sleeve 2 (Fig. 4).

The device is operational with any number of output elements interacting with the load (end elements 7, 8, pin 9). When using a device without end elements 7, 8, it is necessary to install a protruding stroke limiter of the piston (pistons 3, 4) on the sleeve 2 and the cover (covers 5, 6) without holes for the rod.

The operation of the device in the first preferred embodiment (operation on compressed air) is carried out as follows.

When compressed air is supplied to channel B, piston 3 moves to the left, and piston 4 to the right, as a result of the movement the pistons reach the protrusions of the covers 5, 6 and, resting against the limiting protrusions of the rods 7 and 8, set the sleeve 2 to the middle position (Fig. 1). Channels A and C at this moment communicate with the atmosphere.

When compressed air is supplied to channel A, piston 3 moves to the right and, having reached the ledge of bushing 2, pushes it to the right, then piston 3 rests against the limiting protrusion of the main body, and bushing 2 rests against piston 4, which rests against cover 6, thereby the bushing 2 with elements 7,8 and finger 9

- 2 044923 occupies the extreme right position (Fig. 2). Channels B and C at this moment communicate with the atmosphere.

Occupying the extreme left position occurs according to the opposite (mirror) principle relative to occupying the extreme right position.

With the asymmetrical manufacture of the main body, the protrusions of the side covers 5, 6 and the sleeve 2, the principle of fixing the rod in the required (displaced) intermediate position, relative to the central (middle) position, is achieved.

The operation of the device in the second preferred embodiment (operation on compressed air) is carried out as follows (Fig. 3, 4).

The device is also operative with any number of output elements interacting with the load (end elements 7, 8, pin 9). When using a device without end elements 7, 8, it is necessary (as in the first preferred embodiment) to install a protruding stroke limiter of the piston (pistons 3, 4) on the sleeve 2 and the cover (covers 5, 6) without holes for the rod.

When compressed air is supplied to channel B, piston 3 moves to the right, and piston 4 to the left; as a result of the movement, the pistons reach the ledges of sleeve 2 and rest against the body, installing sleeve 2 with rods 7, 8 and pin 9 in the middle position. Channels A and C at this moment communicate with the atmosphere.

When compressed air is supplied to channel C, piston 4 moves to the right and, having reached rod 8, moves sleeve 2 to the right, rod 7 rests against piston 3 and sleeve 2 with rods 7, 8 and pin 9 takes the extreme right position. Channels A and B at this moment communicate with the atmosphere.

Occupying the extreme left position occurs according to the opposite (mirror) principle relative to occupying the extreme right position.

With the asymmetrical manufacture of the main body 1 and the bushing 2, the principle of fixing the rods in the required (displaced) intermediate position, relative to the central (middle) position, is achieved.

The principle of operation of a device under liquid pressure is similar to the principle of working with compressed air, but it is necessary that the channels of liquid lines without high pressure, at the moment of changing the position of the rods, communicate with the main low-pressure liquid line and the expansion tank.

Industrial applicability

A prototype of the device (without finger 9) during testing confirmed its operability, the solution of the task and the achievement of the specified technical result.

During trial operation there were no failures, incomplete switchings or interruptions. It should also be noted that when any of the three declared positions is occupied, the force of activation (movement) of the rod (and/or pin) is the same, therefore the cylinder can fully be called power, providing that all three positions are occupied. To ensure inclusion (movement), the device is also operable with a low degree of tightness of the connections, but when ensuring forceful retention in the occupied position (being under pressure of the working medium), it is necessary to ensure appropriate sealing and compaction in the pistons and side covers.

Claims (4)

1. A three-position pneumatic or hydraulic cylinder, consisting of a housing with end caps, two pistons, a rod, channels for supplying the working medium, with each piston being made with the possibility of limited movement along the rod due to the central protrusion separating the pistons and peripheral protrusions on the rod, and limited movement inside the housing, characterized in that the central projection is made in the form of a sleeve, and on the inner surface of the housing there is an annular projection, while the sleeve and the projection form a sealed movable joint of the shaft-hole type. 2. Three-position cylinder according to claim 1, characterized in that the channels for supplying the working medium are made as follows: separate channels into the chambers formed by each of the pistons and the corresponding end of the housing, and a common channel into the chambers formed by each of the pistons and the central protrusion and sleeve . 3. Three-position cylinder according to claim 1, characterized in that the channels for supplying the working medium are made as follows: separate channels into the chambers formed by each of the pistons and the central protrusion and sleeve, and a common channel into the chambers formed by each of the pistons and the corresponding end of the housing . 4. Three-position cylinder according to claim 1, or claim 2, or claim 3, characterized in that at least one finger is fixed to the sleeve to interact with the load, placed at an angle to the axis of the rod in the bore of the annular protrusion.