SU821663A1 - Distributor valve for power shovel hydraulic system - Google Patents

Description

(54) HYDRODISTRIBUTOR FOR HYDRAULIC SYSTEM OF SINGLE-BIT EXCAVATOR

ly (direction A); in fig. 4 and 5 - sections of the body along the spools, which are moved to the position corresponding to lowering the boom (direction B); in fig. 6 — node I in FIG. 2

The valve 1 (Fig. 1) contains two three-position axially moving spools 2 and 3 (Fig. 2), which are provided with sealing steps 4 and installed in the bores of the housing. The pressure cavities 5 and 6 of the body bores are connected by channels with supply lines 7 and 8 from pumps 9 and 10 (Figs. 1 and 2). The diverting cavities 11-14 (Fig. 2) are connected by channels with diverting lines 15 and 16 (Fig. 1), which are connected to the pinholes and piston cavities of the hydraulic cylinders 17 of the excavator boom swing mechanism. Drain cavities 18-21 (Fig. 2) are connected by channels with drain lines 22 and 23 (Fig. 1). ,

The control units 24 and 25 are connected by supply lines to pumps and pressure chambers of the hydraulic distributors and also to a drain line 26 entering the hydraulic tank 27.

A check valve 28 is built in between the pressure 15 and the drain 26 lines.

The discharge cavity 14 (Fig. 2) is separated from the pressure 5 and drain 19 cavities by two searches 29 and 30 of the spool 2, which are asymmetrically relative to the plane of symmetry of the discharge cavity 14. Skii 29 and 30 are separated by a groove 31. The groove 32 serves to connect discharge cavity 14 with drain cavity 19.

The connecting cavity 14 with the pressure 5 and drain 19 cavities depends on the ratio of the overlaps ho and hf and the stroke of the spool S. The location of the spool and their lengths to and K. They are chosen from the condition that the length of the spool is E and the overlap h is the distance between the cutting edge over the tongue and the corresponding edge of the body, is greater than the stroke of the spool for the tongue separating the discharge cavity from the pressure one, and less than the stroke of the slide valve for the edge separating the same discharge cavity from the drain cavity. This can be expressed by inequalities:

1 U .s;

 - length of the spool sealing ska on the side of the drain cavity;

 the length of the sealing spool on the side of the pressure cavity;

hg is the overlap of the drain, the distance between the respective cutting edges of the spool and the body from the side of the drain cavity;

 the overlap of the head, the distance between the corresponding cutting edges of the spool and the body from the pressure cavity.

The spool 3 has three grooves 33-35, which, when the spool 3 is turned on, connect the corresponding housing cavities.

Caps 37 are fastened to the body 36 of the hydraulic distributor, in which adjustable ynopij 38 are installed, which have the possibility of axial displacement. The stops 38 can be made in the form of adjustable screws that set the spool stroke in the direction B.

The valve works as follows.

The working fluid from pumps 9 and 10 at the neutral position of spools 2 and 3 (Fig. 1 and 2) and spools of control blocks 24 and 25 through pressure pipe 7

and 8, the drain channels of the control blocks 24 and 25 and the drain pipe 26 enters the hydraulic tank 27. When the spools 2 and 3 move in direction A (Fig. 3), the spools of the control blocks 24 and 25 (control blocked) and the flow of working fluid from pumps 9 and 10 through pipelines, 7 and 8 are fed to the spools, and from them through pipe 16 into the piston cavities of the hydraulic cylinders, providing an accelerated boom lift from the two pumps. The working fluid displaced from rod cavities gi; 1, cylinders, through pipeline 15 through grooves 32 and 33 of spools 2 and 3, body channels, pipelines 22 and 23, control blocks 24 and 25, and pipeline 26

0 enters the hydraulic tank 27.

The movement of the spools in the direction of SRI B is carried out selectively (each spool is controlled from a separate lever, and only the control of the spool 3 is blocked by moving the spool of the control unit 24). By moving the spool 3 in the direction B (Fig. 4) and the spool of the control unit 24, the flow of working fluid from the pump 10 is directed through line 8,

Q channels in the housing and the groove of the spool 34, pipeline 15 into the hydraulic rods of the hydraulic cylinders 17. At the same time, the working fluid displaced from the piston cavities through the pipeline 16, the groove 35 of the spool 3, pipelines 23 through the control unit 24

5 and the pipe 26 enters the hydraulic tank 27. This movement of the spool 3 corresponds to turning the boom to the lower position (lowering the boom) using the power of one nasra (“boom head). At the same time, the maximum allowable speed of boom rotation is limited by the size of the slit formed by the edge of the housing and the edge of the sealing edge on the side of the groove 35 of the spool 3. The size of the slit depends on the stroke of the spool, which is limited by an adjustable stop 38.

When moving the valve 2 in the direction B of the pressure valve 5 and the outlet cavity 14 are not connected by the groove 39 of the valve, because the overlap size h is chosen larger than the stroke of the valve, and the drain cavity 18 by the groove 40 is connected to the outlet cavity I. the position of the spool, the working fluid from the hydraulic cylinders 17 under the action of an external load through the pipeline 16, the channels in the control valve body enters the drain cavity 11, which is connected by a groove 40 of the spool 2 to the drain cavity 18. From the drain cavity 18 the working fluid on line 26 enters the hydraulic reservoir 27. When this rod cavity filling cylinders 17 comes from the drain pipe 28 through a check valve.

This movement of the spool 2 corresponds to the rotation of the boom to the lower position (lowering of the boom) in the pumpless mode. The pump 9 in this case supplies the working fluid through the pipeline 7 through the control block 24 and the pipeline 26 to the hydraulic tank 27. The boom lowering speed is regulated within wide limits by the slit formed by the edge of the body sealing lip and the edge of the sealing lip formed by the groove 40 2 spool.

The slit section depends on the stroke of the spool 2 when it is moved, and the maximum speed, as on spool 3, is limited by the adjustable stop 38.

In this case, the pump 9 can be used to drive other mechanisms of the excavator. In the same position of the spool, the diverting cavity 14 is connected to the drain cavity 19, since the overlap HO is smaller than the stroke of the spool. When the pump 9 is turned on for any movement through the cavities 19, the groove 31 and the diverting cavity

14, an additional make-up of the rod end of the hydraulic cylinders 17 is performed. Thus, pump-free lowering of the boom while using pumps to drive other mechanisms 5 leads to an increase in productivity.

Claims (2)

1. USSR author's certificate number 250629, cl. E 02 F 9/22, 1968. five 2. USSR author's certificate number 611990, cl. E 02 F 9/22, 1972.  C / iue To and, c / 1sndru. piston no / iocmb Dm pump 10 K 1 and / 1 st week by / guest. C / iu5 To cylinder porscheib pooost From the pump ID / G to the cylinder stockpile strip RT L to the cylinder of the piston nofiocmb Dm pump W K and, and / 1indru shtoBob cavity From the pump 9 OZh 23