JPH0224380Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a rear frame of a mobile crane.

The outline of the structure of a conventional crane truck will be explained with reference to FIG. 1. 10 generally indicates the crane truck, 12 is a rear frame that constitutes the vehicle body, 14 is a running wheel, 16 is a cab for traveling, and 18 is a crane operation wheel. 20 is a crane base; 22 is a crane boom mounted on the crane base 20 so as to be vertically and telescopically; 24 and 26 are rear frames 1;
The front and rear outriggers are attached to the frame 12 and extend in the width direction when the crane is in use, and are used to hold the ground by means of jacks (not shown) provided at the tips and lift and stably support the frame 12. It's summery. In this type of crane vehicle, when the crane is used, various operations such as raising and lowering the boom 22, extending and retracting the boom 22, extending the outriggers 24 and 26 outward in the width direction of the vehicle, and contracting and retracting them are usually carried out by a hydraulic response device. It is beginning to be practiced;
Therefore, an engine-driven oil pump for operating the hydraulic response device and a tank for storing hydraulic oil are installed. In addition, the above hydraulic response device is
Each requires a relatively large capacity, so a large-capacity tank of several hundred liters is usually manufactured and installed on the rear frame, and a large-diameter pipe is connected between it and the engine-driven large-capacity oil pump. Since they had to be placed at a distance, manufacturing costs increased and at the same time there were problems that required a large amount of space.

The present invention was devised in view of the above, and has a generally trapezoidal cross-sectional shape that is open at the bottom and bulges upward on the bottom surface of the rear frame, which has a generally rectangular closed cross-sectional shape and extends in the longitudinal direction of the vehicle body. , in which a recess extending in the longitudinal direction of the vehicle body is formed, and a part of the rear frame is horizontal so that at least a pair of front and rear cross members disposed inside the rear frame are flush with the top surface of the recess. The hydraulic oil tank is configured as a closed section hydraulic oil tank that is partitioned above the recess by a partition plate arranged in the direction, and pressure oil is supplied to the hydraulic response device within the recess in the hydraulic oil tank portion. The gist of this paper is a rear frame of a crane truck, which is characterized by being equipped with an oil pump for supplying oil.

Embodiments of the present invention will be described in detail below with reference to FIGS. 2 to 4. In the first embodiment shown in FIGS. 2 and 3, the rear frame 12 is
It consists of a top plate 28, a pair of side plates 30, and a bottom plate 32, and is formed to have a substantially rectangular closed cross-sectional shape in a vertical plane in the vehicle width direction. The bottom plate 32 consists of side flanges 34 on both sides in the vehicle width direction parallel to the top plate 28, and a central raised portion 36 whose cross-sectional shape in the vehicle width direction plane is trapezoidal with a downward opening. As a result, a trapezoidal recess 38 extending in the longitudinal direction of the vehicle body is formed. In this embodiment, the top plate 28 and the side plates 30 are made of separate plates and are fixed by welding, but a single plate may be bent to form a single U-shaped member. The flange portion 34 and the central raised portion 36 may be manufactured by bending a single plate.

Further, inside the rear frame 12, a plurality of cross members 40 are arranged at appropriate intervals in the longitudinal direction of the vehicle body, and are welded and fixed to the top plate, side plate, and bottom plate. In the illustrated embodiment, as shown in FIGS. 2 and 3, the recess 38 is partitioned in the longitudinal direction of the vehicle body by a pair of adjacent cross members 40a and 40b, and the top surface of the recess 38, that is, the central raised portion 3
The partition plate 4 is arranged horizontally to form one plane with the partition plate 6.
A hydraulic oil tank 42 is formed having a box-shaped closed cross section vertically partitioned by 0c. A plurality of (three in the illustrated case) oil pumps 44 are serially installed in the recess 38 in the lower portion of the tank 42, and communicate with the inside of the tank 42, respectively. These pumps 44 are driven by a drive shaft 56 via a universal joint 54 from a PTO device 52 (well-known working power take-off device) of a transmission 50 connected to an engine 46 via a clutch 48. . 58 is a discharge pipe that supplies the pressure oil discharged from the oil pump 44 to a pressure-responsive device (not shown); 60 is a return pipe that returns the return oil from the pressure-responsive device to the tank 42; and 62 is a cover for an oil filler port attached to the top plate 28. It is.

According to the above configuration, since the hydraulic oil tank 42 is provided inside the rear frame 12 of the crane vehicle, there is no need to separately manufacture a tank, and there is no need to secure a special space for the tank. Cost reduction, weight reduction, and additional space can be obtained. Also, since the oil pump 44 is placed in the recess 38 on the bottom of the rear frame and connected to the hydraulic oil tank 42, the large diameter pressure oil supply/drainage pipe that was conventionally placed between the tank and the oil pump is omitted. This has the advantage of reducing manufacturing costs and weight, and requiring no installation space. Furthermore, since the hydraulic oil tank 42 is formed over the entire width of the rear frame 12, the dimension in the longitudinal direction of the vehicle body required to secure the required tank capacity is reduced, and the hydraulic oil tank 42 is concentrated in one place. It is compactly formed. Therefore, the high-temperature hydraulic oil that has worked in the pressure-responsive device and returned to the same tank is effectively cooled by convection and agitation, improving the durability of the hydraulic oil itself and reducing the above pressure. This has the advantage of improving the durability of rubber seals and packings that are placed in various parts of response devices, oil pumps, piping, etc. and are in contact with hydraulic oil.

In the above embodiment, one or more partition walls (of course, one or more communication holes are provided to allow the flow of hydraulic oil) are arranged between the cross members, that is, the partition walls 40a and 40b, so that the operation inside the tank 42 can be controlled. It is also possible to prevent the oil from rippling, and the number of oil pumps 44 to be installed can be arbitrarily set to one or more depending on the capacity of the pump, the space of the recess 38, and the surrounding structures. can.

As mentioned above, the rear frame of the crane vehicle according to the present invention has a substantially rectangular closed cross-sectional shape as a whole and extends in the longitudinal direction of the vehicle body.
A part of the rear frame has a substantially trapezoidal cross-sectional shape that is open at the bottom and bulges upward, and has a recess that extends in the longitudinal direction of the vehicle body, and a portion of the rear frame has at least a pair of front and rear crosses disposed inside the frame. The hydraulic oil tank is configured as a closed section hydraulic oil tank partitioned above the recess by a member and a partition plate arranged horizontally so as to be flush with the top surface of the recess. An oil pump is installed in the recess to supply pressure oil to the hydraulic response device, which reduces the weight and manufacturing cost of the crane truck, and provides a large-capacity hydraulic oil tank and hydraulic oil supply. This is extremely beneficial because the installation space for the exhaust pipe can be greatly reduced, and the durability of hydraulic oil, rubber seals, packing, etc. can be improved.

[Brief explanation of the drawing]

Fig. 1 is a schematic side view of a crane truck to which the present invention is applied, Fig. 2 is a side view showing an enlarged main part of an embodiment of the present invention, and Fig. 3 is shown along the - line in Fig. 2. FIG. 10... Crane truck, 12... Rear frame,
38... Recess, 40a, 40b... Cross member, 42... Hydraulic oil tank, 44... Oil pump, 62... Oil filler port cover.

Claims (1)

[Scope of utility model registration request] A recess is formed on the bottom surface of the rear frame, which has a generally rectangular closed cross-sectional shape and extends in the longitudinal direction of the vehicle body, and has a generally trapezoidal cross-sectional shape that is open at the bottom and bulges upward, and extends in the longitudinal direction of the vehicle body. In the above, a part of the rear frame is arranged in the same manner by at least a pair of front and rear cross members disposed inside the rear frame and a partition plate disposed horizontally so as to form one plane with the top surface of the recess. It is configured as a closed-section hydraulic oil tank partitioned above the recess, and is characterized in that an oil pump for supplying pressure oil to the hydraulic response device is disposed within the recess in the hydraulic oil tank portion. Rear frame of crane truck.