JP4835403B2 - Hydraulic oil tank for construction machinery - Google Patents

Description

  The present invention relates to a hydraulic oil tank having an improved return structure for filtering return oil from a hydraulic actuator through a filter and returning it to a tank body in a construction machine such as a hydraulic excavator.

  As shown in FIGS. 3 and 4, this type of hydraulic oil tank has a bottomed cylindrical filter case 2 mounted in a tank body 1 to accommodate a return filter 3 therein, and a plurality of return pipes 4 from a hydraulic actuator. The return oil flowing back through the filter is filtered by the return filter 3 and then returned to the tank body 1 by the return pipe 5 penetrating through the center of the filter case bottom wall 2a.

  The return filter 3 is placed on the bottom wall 2 a of the filter case 2 and is held by the push spring 6.

  In the figure, 7 is a suction filter for filtering feed oil, and 8 is a suction pipe.

  In this tank structure, when return oil from the hydraulic actuator (particularly high pressure oil in the main pipe) is introduced toward the side surface of the return filter 3, the return oil directly hits the side surface of the filter (filter paper). Perishable.

  As a countermeasure against this point, it is conceivable to attach a baffle plate to the return oil introduction portion to avoid direct impact of the return oil on the side surface of the filter, but this is not a good solution because the structure becomes complicated and the assembly becomes troublesome.

Under such circumstances, conventionally, as shown in Patent Documents 1 and 2, all return pipes 4 are connected above the return filter 3, that is, above the filter case side wall 2b.
JP 2005-282805 A JP-A-7-27102

  However, as a result of all return pipes 4 ... being concentrated in the upper part of the case side wall and connected in a paw-like shape, the connection of the return pipes 4 ... is limited, the shape of the return pipe 4 and the connection structure to the filter case 2 are complicated, Assembling the tank is troublesome and disadvantageous in terms of manufacturability and cost.

  Note that this problem can be alleviated if the entire tank including the filter case 2 is enlarged, but this is particularly difficult in a small hydraulic excavator where the tank installation space is limited.

  Accordingly, the present invention provides a construction machine that can simplify the connection structure by connecting the return pipes to the filter case in a distributed manner while avoiding direct hitting of the return oil on the filter side surface, and relaxing the restriction on the connection of the pipes. The hydraulic oil tank is provided.

  According to the first aspect of the present invention, a bottomed cylindrical filter case for accommodating a return filter for filtering the return oil is provided in the tank body in which the hydraulic oil is stored, and a plurality of return pipes are provided in the filter case. In a hydraulic oil tank of a construction machine connected to the side wall of the case in a communicating state, a filter receiving plate is provided at a lower portion in the filter case with a space between the filter case bottom wall and the return filter It is provided on the filter receiving plate, and one or more return pipes are connected to the side wall of the filter case below the filter receiving plate.

  The invention of claim 2 is the structure of claim 1, wherein a return pipe for returning the return oil filtered by the return filter into the tank body is provided in a state of passing through the bottom wall of the filter case and the filter receiving plate, A filter receiving plate is supported by the return pipe.

  According to the present invention, since the filter receiving plate is provided in the lower part in the filter case and the filter is installed in a state of being floated from the case bottom wall, a part of the return pipe can be connected to the lower part of the case. That is, the return pipe can be dispersedly connected to the lower part and the upper part of the filter case while avoiding direct hitting of the return oil to the side surface of the filter.

  Moreover, it is only necessary to extend the filter case in the height direction, and there is no need to expand the filter case and the tank body in the radial direction.

  Thereby, since the restriction | limiting of the connection of return piping is eased, the shape and connection structure of return piping are simplified, and it becomes advantageous in terms of manufacturability and cost. The effect of this point is particularly noticeable in a small tank mounted on a small excavator. Alternatively, the tank can be miniaturized and the space occupied by the tank can be reduced.

  Further, since the return oil can be introduced and filtered from the upper and lower sides of the return filter, the filter surface of the filter can be widely used. For this reason, the lifetime of the filter can be improved.

  On the other hand, according to the invention of claim 2, since the filter receiving plate is supported by using the return pipe originally provided in the tank, it is not necessary to add a dedicated member for supporting the plate. For this reason, it is advantageous for simplification of the tank structure, and there is no possibility that the flow of hydraulic oil in the filter case is hindered.

  An embodiment of the present invention will be described with reference to FIGS.

  The basic configuration of the hydraulic oil tank according to the embodiment is the same as that of the known technique shown in FIGS.

  That is, a bottomed cylindrical filter case 12 is mounted in the tank body 11 and a return filter 13 is accommodated therein, and return oil flowing back from the hydraulic actuator through a plurality of return pipes 14 is filtered by the return filter 13. Then, it is returned into the tank body 11 by a return pipe 15 provided at the center of the filter case bottom wall 12a.

  16 is a push spring that pushes the return filter 13 downward, 17 is a suction filter that filters the feed oil, and 18 is a suction pipe.

  In this hydraulic oil tank, a filter receiving plate 19 is provided in the lower part of the filter case 12 with a gap A (see FIG. 1) between the filter case bottom wall 12a and the return filter 13 is provided with this filter receiving plate. 19 and is pressed and held by the pressing spring 16.

  The filter receiving plate 19 is attached to the upper end portion of the return pipe 15 penetrating the filter case bottom wall 12a in a state where the center portion is penetrated by the pipe 15, and one or a plurality (two in the illustrated example) of the return plates 15 are returned. The pipes 14 are connected to the lower part of the case side wall 12b below the filter receiving plate 19 (within the interval A).

  In other words, a pipe connection portion where the return oil does not directly hit the side surface of the filter is formed at the lower part of the filter case 1 side wall 12b, and the return pipes 14 are dispersed and connected to the upper and lower parts of the filter case side wall 12b. .

  According to this configuration, the return pipes 14... Are compared with the case where all the return pipes 4... Since it can be dispersed vertically, the restriction of the contact is greatly eased, and each return pipe 14 can be connected by selecting a position where both the upper and lower sides can be easily connected, thereby simplifying the pipe shape and the pipe structure. it can.

  Moreover, it is only necessary to extend the filter case 12 in the height direction by the interval A, and there is no need to expand the filter case 12 and the tank body 11 in the horizontal direction.

  For this reason, the assembly of the tank is simplified and the productivity of the tank is remarkably improved. The effect of this point is particularly noticeable in a small tank having a limited connection area of the return pipes 14... And is very advantageous for a small construction machine in which it is difficult to increase the size of the tank.

  Alternatively, it is possible to reduce the size of the tank instead of assembling, and this can reduce the occupied space of the tank, which is also advantageous for a small construction machine.

  Further, since the return oil can be introduced and filtered from the upper and lower sides of the return filter 13, the filtration surface of the filter 13 can be widely used. For this reason, the lifetime of the filter 13 can be improved.

  On the other hand, since the return pipe 15 originally provided in the tank is slightly extended and the filter receiving plate 19 is supported by the pipe 15, it is not necessary to add a dedicated member for supporting the plate 19. For this reason, it is advantageous for simplification of the tank structure, and there is no possibility that the flow of hydraulic oil in the filter case 12 is hindered.

  Note that the support structure of the filter receiving plate 19 may be changed to another structure, for example, a support member having a loose mesh is provided between the plate 19 and the filter case bottom wall 12a.

It is sectional drawing of the tank concerning embodiment of this invention. FIG. 2 is a partially enlarged view of FIG. 1. It is sectional drawing of the conventional tank. It is the IV-IV line expanded sectional view of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Tank body 12 Filter case 12a Filter case bottom wall 12b Filter case side wall 13 Return filter 14 Return piping 15 Return pipe 19 Filter receiving plate A Space | interval of filter case bottom wall and filter receiving plate

Claims (2)

  A bottomed cylindrical filter case that houses a return filter for filtering the return oil is provided in the tank body in which the hydraulic oil is stored, and a plurality of return pipes communicate with each other in the filter case. In a hydraulic oil tank of a construction machine connected to a side wall, a filter receiving plate is provided at a lower portion in the filter case with a space between the bottom wall of the filter case, and the return filter is provided on the filter receiving plate. And a hydraulic oil tank for a construction machine, wherein one or more return pipes are connected to the side wall of the filter case below the filter receiving plate.   A return pipe for returning the return oil filtered by the return filter into the tank body is provided in a state of passing through the bottom wall of the filter case and the filter receiving plate, and the filter receiving plate is supported by the return pipe. The hydraulic oil tank for construction machinery according to claim 1.

Images