JPH02299931A - Liquefied petroleum gas type forklift - Google Patents

Abstract

PURPOSE:To maintain the balance of reservoirs in right and left directions and prevent hydraulic oil from being overheated by connecting the hydraulic oil reservoir and the fuel oil reservoir provided on both right and left sides of the reservoirs to each other by an oil conducting pipe, and connecting the air chambers of both reservoirs to the upper chamber of a lift cylinder by oil conducting pipes. CONSTITUTION:A forklift truck uses liquefied petroleum gas as power fuel. A hydraulic oil reservoir 26 and a fuel oil reservoir 28 are formed in a vehicle body frame 20L, 20R; 22L, 22R symmetrically in relation to a center engine compartment 24 on both right and left sides of it. In this case, both the oil reservoirs 26 and 28 are connected to each other by an oil conducting pipe 34 both the ends of which are connected to drain ports for cleaning 26a and 28a provided at the lower portion of the reservoirs. Air chambers 26b and 28b formed above the level of oil in the oil reservoirs 26 and 28, respectively, are connected to the upper chamber of a lift cylinder not shown in the figure through oil conducting pipes 38 combined by a branch pipe 36. Thus, the fuel oil reservoir 28 is used as the second hydraulic oil reservoir.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a liquefied petroleum gas forklift truck, and more particularly to an improvement in a vehicle body structure that rationally prevents overheating of hydraulic fluid.

[Conventional technology] Forklifts are classified into several types depending on their power sources, but at least gasoline-powered, diesel-powered, and liquefied petroleum gas-powered forklifts are equipped with engines that have different loading capacity due to productivity-oriented requirements. The vehicle body frame is standardized for each capacity, and generally has a frame structure in which oil tanks for hydraulic oil and fuel oil are formed almost symmetrically on both sides of the engine room. In order to prevent overheating of hydraulic fluid due to harsh cargo handling operations,
Measures have been taken such as installing a dedicated oil cooler.

[Problem to be solved by the invention] Conventional liquefied petroleum gas forklifts are characterized by having a unique liquefied petroleum gas container mounted on the vehicle body, and the oil tank of the fuel oil field formed on the body frame is , above) Due to their common structure, they are currently left virtually unused.

However, if a vehicle is operated with one of the symmetrically installed oil tanks left empty, the vehicle body will naturally lack left and right balance, which may impede stability.

The present invention utilizes the oil tank of the above fuel oil field to
To stabilize the vehicle body and at the same time prevent the hydraulic fluid from overheating,
This is a technical problem that must be solved.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a liquefied petroleum gas forklift truck having a body frame in which oil tanks for hydraulic oil and fuel oil are formed almost symmetrically on both sides of the engine room. A new configuration is adopted in which the lower part of the inner oil tank is connected by an oil guide pipe to store hydraulic oil in both oil tanks, and the upper chamber of the lift cylinder and the air chamber of the inner oil tank are communicated by an air guide pipe. .

When connecting the inner oil tank with the oil guide pipe, it is desirable to use the cleaning outlet provided at the bottom of the inner oil tank, and the air guide pipe is connected to the upper chamber of the lift cylinder and the air chamber of the hydraulic oil tank. It is preferable to interpose a branch pipe in a part of the existing air guide pipe connecting the fuel oil tank, and to connect the branch pipe and the air chamber of the fuel oil tank by means of a supplementary air guide pipe.

[Function] Since the empty fuel oil tank is transformed into a hydraulic oil tank, the heat capacity increases as the absolute amount of stored hydraulic oil increases, and the cooling efficiency also improves due to the expansion of the heat dissipation area. Oil overheating is reasonably suppressed. Utilizing fuel oil tanks in this way also restores the stability of the car body, which has been pointed out for some time.

[Example] Hereinafter, an example of the present invention will be described based on FIGS. 1 and 2.

FIG. 1 shows an example of the entire structure of a liquefied petroleum gas forklift 10. The forklift 10 carries a liquefied petroleum gas container, which is the motive fuel, through a support stand 14 attached to the rear column 12 of the Heradguard. It is equipped with 16.

Vehicle body frame 2 with a common structure for the purpose of generalization
0, as shown in Fig. 2, the central engine room is constructed by welding together the side frame 2OR12OL, which is formed in a vertical cross-sectional shape, and the inner plate 22R122L, whose front part is bent at an almost right angle. Almost symmetrical sealed oil tanks are formed on both the left and right sides with 24 in between, and normally one is the hydraulic oil tank 26 and the other is the fuel oil tank 2.
It functions as 8. In addition, 30 is engine room 2
It is an engine hood that can be opened and closed and covers the upper part of the engine.
32 is an undercover that closes off the lower part of the engine room 24.

The most characteristic structure of the present invention is that the inner oil tank 26.28
This is because of the simple connection structure and the fact that the virtually unused fuel oil tank 28 is utilized. In other words, the inner oil tanks 26 and 28 are connected to each other by an oil guide pipe 34 using cleaning discharge ports 26a and 28a provided at the lower part thereof, and hydraulic oil is stored in each of the inner oil tanks 26 and 28. ing.

The air chambers 26b, 28b formed above the oil level in the inner oil tank 26, 28 are communicated with an upper chamber of a lift cylinder (not shown) via an air guide pipe 38 integrated by a branch pipe 36. Although not clearly shown in the drawings, it goes without saying that the hydraulic oil can be discharged in the same manner as in the past by appropriately bending the oil guide pipe 34 and removing the pipe joint.

Therefore, according to the present invention, the fuel oil tank 2B, which has conventionally been left empty, is utilized as a second hydraulic oil tank by connecting it to the hydraulic oil tank 26, and in addition to doubling the amount of hydraulic oil, the fuel oil tank 2B is also connected to the hydraulic oil tank 26. The unevenly distributed center of gravity of the vehicle is also corrected at the same time.

Moreover, even with this transformation of the fuel oil tank 28, there is no change in the oil supply piping system for the various actuators, and in order to connect the upper chamber of the single-acting type lift cylinder and the air chamber 28b of the fuel oil tank 28, there will be no change in the oil supply piping system for the various actuators. It is sufficient to replenish a portion of the oil guide pipe 38 and the branch pipe 36.

[Effects of the Invention] As described above in detail, the present invention enables the second operation by connecting the fuel oil tank, which has conventionally been left empty, to the hydraulic oil tank in a liquefied petroleum gas forklift. Since it is used as an oil tank, the unevenly distributed center of gravity of the vehicle can be corrected, and the left and right balanced stability can be immediately restored.
: Overheating of the hydraulic oil is reliably prevented by suppressing temperature rise and improving cooling efficiency due to the expansion of the heat dissipation area, so ancillary equipment such as oil coolers can be effectively omitted.

[Brief explanation of the drawing]

FIG. 1 is a side view illustrating a liquefied petroleum gas forklift, and FIG. 2 is a longitudinal cross-sectional view showing a vehicle body frame structure. 2OR, 2OL...Side frame 22 R122L...Inner plate 24...Engine room 26...Hydraulic oil tank 28...Fuel oil tank 34...
Oil guide pipe 36... Branch pipe 38... Air guide pipe

Claims (1)

[Claims] (1) In a forklift that has a body frame in which oil tanks for hydraulic oil and fuel oil are formed almost symmetrically on both sides of the engine room, and that uses liquefied petroleum gas as the motive fuel, the lower parts of the oil tanks are A liquefied petroleum gas forklift truck, characterized in that hydraulic oil is stored in both oil tanks by connecting the two oil tanks with an oil guide pipe, and the upper chamber of the lift cylinder and the air chambers of both oil tanks are communicated with each other by an air guide pipe.