RU2254289C2 - Hydraulic jack - Google Patents

Abstract

FIELD: mechanical engineering; hydraulic drives.

SUBSTANCE: invention can be used in hydraulic jacks with locking of load at no operating pressure. Proposed jack contains housing with piston and hollow rod and locking mechanism. Said mechanism is made in form of two coaxial intercoupled screw pairs of equal pitch with non-self-holding and self-holding thread. Jack contains also additional piston and support installed in hollow rod and engaging with outlet member. Screw of non-self-holding pair is stationary secured in housing, and hollow rod is movably connected with said screw by means of non-self-holding thread. Additional piston is installed for embracing the housing from outside and for displacement by means of hollow rod through support, being essentially said outlet member. Screw of self-holding pair is installed for movement in housing cover by means of self-holding thread to accommodated said pair inside housing space. Guide is secured on hollow rod to transmit torque to screw of self-holding pair on which pin is secured and slot for guide is made. Compression spring is installed between pin and guide to build tangential force.

EFFECT: provision of accurate mounting of outlet member.

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Description

The invention relates to mechanical engineering, in particular to a hydraulic actuator, and can be used in hydraulic lifting mechanisms with load securing in the absence of working pressure.

A hydraulic jack is known (SU No. 1726364 A1, publ. 15.04.92), including a base with a piston and a locking mechanism located in it, made in the form of two kinematically connected screw pairs with self-braking and non-braking threads, connected by a gear transmission, and an output element made in the form of a glass covering the base.

A disadvantage of the known device is the design complexity due to the presence of a gear transmission and the parallel arrangement of two screw pairs. In addition, the known device does not provide accurate installation of the output element, since after depressurizing the output element is lowered due to the axial clearance in the non-self-locking thread.

The closest device of the same purpose to the claimed invention in terms of features is a hydraulic jack, disclosed in SU 1694474 A2, 12/18/1989 - 2 C. and comprising a housing with a piston with a hollow rod located in it and a locking mechanism made in the form of two coaxial, interconnected screw pairs of equal pitch with non-self-braking and self-braking threads, an additional piston mounted in the nut bore, with the possibility of axial movement relative to the rod, the nut is sealed relative to the housing, and the housing is provided with inlet and outlet channels in communication with said bore. A support is installed in the hollow stem, which interacts with the output element and has axial play, the value of which is less than the axial play of a non-self-braking screw pair. The non-self-locking pair screw is fixedly mounted in the housing, and the hollow rod is movably connected by means of a non-self-locking thread to this screw. This device is taken as a prototype.

Signs of the prototype, which are common with the claimed invention is a housing with a piston with a hollow rod placed in it; the fixing mechanism, made in the form of two coaxial, interconnected screw pairs of equal pitch with non-self-braking and self-braking threads; additional piston; a support mounted in a hollow stem and interacting with the output element; the non-self-locking pair screw is fixedly mounted in the housing; the hollow stem is movably connected by means of a non-self-locking thread to a screw.

The known device adopted for the prototype has several disadvantages. It does not provide an accurate installation of the output element when the operating pressure is released, since the output element is lowered due to the axial clearance in the non-self-locking thread. Also a disadvantage of the known device are large dimensions, due to the location of the nut outside the housing. The large dimensions of the device limit its use, especially in transport engineering, where particularly stringent requirements are imposed on weight and dimensions. In addition, an open thread on the housing makes it difficult to operate the device.

The objective of the invention is to increase the accuracy of fixation of the output element, reducing the overall dimensions of the device and expanding its technological capabilities.

The problem is solved due to the fact that the known device, comprising a housing with a piston with a hollow rod and a fixing mechanism made in the form of two coaxial, interconnected screw pairs of equal pitch with non-self-braking and self-braking threads, an additional piston and a support installed in the hollow stem and interacting with the output element, while the non-self-locking pair screw is fixedly mounted in the housing, and the hollow stem is movably connected by means of a non-self-locking thread to this screw, additional The exhaust piston is installed with the housing outside and able to move the hollow rod through the support and is the mentioned output element, while the screw of a self-braking pair is movably mounted in the housing cover by means of a self-braking thread to accommodate this pair inside the body cavity, a lead for transmitting torque is fixed on the hollow stem a self-braking pair screw, on which the pin is fixed and the lead for the lead is made, and a compression spring is installed between the pin and the lead for creating a force in the tang cially direction.

Distinctive features of the proposed device from the prototype are an additional piston mounted with the housing outside and the ability to move the hollow rod through the support and which is the mentioned output element; a self-braking pair screw is movably mounted in the housing cover by a self-braking thread to accommodate this pair inside the body cavity; a leash is fixed on the hollow stem to transmit torque to the self-braking pair screw; a pin is fixed on the screw and a groove for the leash is made; a compression spring is installed between the pin and the leash to create a tangential force. Distinctive features in combination with the known ones allow to increase the accuracy of fixation of the output element, reduce the overall dimensions of the device, and also expand its technological capabilities.

The proposed device is illustrated by the drawings shown in figures 1-2.

Figure 1 shows a device, a longitudinal section;

figure 2 is a section aa.

The hydraulic jack comprises a housing 1, in which a piston 2 is placed with a rod 3 connected by a non-self-locking thread with a screw 4. The screw 4 is fixedly mounted in the housing 1. An additional piston 5 is placed on the rod 3, which seals the housing 1 and has the possibility of limited axial movement on the rod 3. In the rod 3, a support 6 is fixedly mounted with a spherical surface to reduce friction during rotation of the rod 3. The screw 7 is self-braking thread movably connected to the cover 8. The thread pitch of screws 4 and 7 is equal. To transmit torque from the rod 3 to the screw 7, the lead 9 is fixedly mounted on the rod 3 and the pin 10 on the screw 7. A compression spring 11 is installed between the pin 10 and the lead 9 to create a tangential force, there is a screw 7 in the screw 7 for movement relative to the rod groove 12.

In the housing, channels 13 and 14 are made for supplying the working medium to the cavity 15, 16 and dumping the working medium from the cavity 17 through the channel 18.

The device operates as follows.

To lift the load, the working medium through the channels 13 and 14 is supplied under pressure under the piston cavities 15 and 16, and the cavity 17 is connected to the drain. The piston 2 and the additional piston 5, mounted on one rod 3, move up together and the bearing 6 abuts against the additional piston 5. The rod 3 is scrolled by the non-self-locking thread of the screw 4 and the lead 9 through the pin 10 rotates the screw 7 by the force of the spring 11. Since the thread pitch screws 7 and 4 equal, screw 7 moves with the rod 3 and pistons 2 and 5 together with the same speed. In this case, the screw 7 due to the small force of the spring 11, sufficient for idle rotation of the screw 7, is pressed by the end face to the additional piston 5 along its entire lifting path without a load from the load.

In case of emergency pressure relief or shutdown of the working medium, the additional piston 5 does not fall down, as it is in constant contact with the end face of the screw 7.

To move the pistons 2 and 5 downward, the working medium is supplied under pressure into the cavity 17, and the cavities 15 and 16 are connected to the drain. The piston 2 will begin to move down, the rod 3, turning on the thread of the screw 4 with a lead 9 and abutting against the vertical surface of the groove 12, will also rotate the screw 7 in the opposite direction. A gap will appear between the ends of the screw 7 and the additional piston 5, and the piston 5 connected to the rod 3 will also move down. All moving parts will return to their original position.

When moving the pistons 2 and 5 with the load down, the threads of the screw pairs will be loaded with the weight of the load. Since lowering the load using screw pairs requires significantly less effort, unlike lifting, the movement of the additional piston 5 with the load is carried out by the force of one piston 2.

The force created by the device is determined by the forces developed by the piston 2 and the additional piston 5 when moving the screw pairs without load, and lowering the load is carried out by one piston 2. The overall dimensions are reduced.

An advantage of the invention is that it allows:

- to increase the accuracy of fixing the output element due to the fact that the torque from the rod to the screw is carried out by a leash mounted on the rod and spring-loaded relative to the screw;

- to reduce the overall dimensions of the device due to the fact that an additional piston is installed with the housing outside, and the screw of a self-braking screw pair is placed inside the cavity of the housing;

- expand the technological capabilities of the device, use it as a clamping device in the tooling for machining parts due to the fact that the screw is spring-loaded in the tangential direction and is pressed end to end to the output element;

- improve the operational characteristics of the device due to the fact that all screw pairs are located inside the housing.

Claims (1)

A hydraulic jack comprising a housing with a piston with a hollow rod and a locking mechanism made in the form of two coaxial, interconnected screw pairs of equal pitch with non-self-braking and self-braking threads, an additional piston and a support mounted in the hollow stem and interacting with the output element wherein the screw of a non-self-locking pair is fixedly mounted in the housing, and the hollow rod is movably connected by means of a non-self-locking thread to this screw, characterized in that the additional piston is It is connected with the housing outside and the ability to move the hollow rod through the support and is the mentioned output element, while the screw of a self-braking pair is movably mounted in the cover of the body by means of a self-braking thread to accommodate this pair inside the cavity of the body, a leash is fixed on the hollow rod to transmit torque to the self-braking screw the pair on which the pin is fixed and the groove is made for this leash, and a compression spring is installed between the pin and the leash to create a tangential force enii.

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