JPH0256249B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to a drive mechanism for an oil pump that supplies hydraulic oil to a hoist cylinder for raising and lowering a vessel of a dump truck, for example.

(Prior Art) Conventionally, in this type of oil pump drive mechanism, as shown in FIG. 11, an oil pump 2 is provided with a PTO 1 that extracts power from the engine, and a control valve 3 that switches the flow of hydraulic oil. They were separated from each other and drivingly connected by a drive shaft 39. Separating the PTO 1 and the oil pump 2 in this way has the disadvantage of making the device large and complicated.
1, an oil pump 2, and a control valve 3 have been integrated into a compact device. (Refer to Japanese Patent Publication No. 59-16967) (Problems to be Solved by the Invention) However, the output gear shaft 10a of the PTO 1 and the pump drive gear shaft 10b of the oil pump 2 are separated from each other and formed separately. Since the convex portion 40 and the concave portion 41 are drivingly connected, the respective shafts 10a, 1
Bearing members 42 and 43 are required at both ends of shaft 0b, and the number of bearing members 42 and 43 increases, which complicates the shaft support structure, and loosens the connection uneven parts 41 and 40 of both shafts 10a and 10b, reducing transmission efficiency. Not only does this worsen, but the connecting uneven portions 41, 40
It also had the disadvantage of being under heavy load and weakening its strength.

Structure of the Invention (Means for Solving the Problem) In view of this problem, the present invention provides a PTO that extracts power from the engine and an oil pump driven by the PTO adjacent to each other, and provides an output of the PTO. A single shaft serves as both the gear shaft and the drive shaft of the oil pump, and the shaft support structure includes a bearing member that supports one end of the shaft within the PTO, and the other end of the shaft within the oil pump. It is constructed by a bearing member that supports the.

(Function) The oil pump drive shaft is directly driven by the PTO output gear shaft.

(Embodiment) An embodiment in which the present invention is embodied in a dump control mechanism of a dump truck will be described below with reference to FIGS. 1 to 10.
1, the cases 4, 5, and 6 of the oil pump 2 and the control valve 3 are formed separately from each other, and are connected to each other by bolts 7 to form one housing as shown in FIG.

An idler gear shaft 8 fixed to the lower part of the case 4 of the PTO 1 supports an idler gear 9 through a pair of ball bearings 9a to which rotation from the engine is transmitted via a transmission. Furthermore, an output gear shaft 10 in the PTO is located at the center of the case 4 of the PTO 1 and the center of the case 5 of the oil pump 2.
A and a pump drive gear shaft 10b in the oil pump 2. One shaft 10 serves as the P.A.
It is rotatably supported by a ball bearing 11 in the case 4 of the T.O1 and a pair of bearing bushes 12 in the case 5 of the oil pump 2. And a ball bearing 11 as the bearing member.
A shaft support structure for the dual-purpose shaft 10 is constituted by one of the pair of bearing bushes 12. In addition, an output gear 14 is supported in the case 4 of the PTO 1 so as to be movable in the axial direction with respect to a spline shaft portion 13 formed on the output gear shaft 10a, and a pair of bearing bushes 12 in the case 5 of the oil pump 2 are supported. A pump drive gear 15 is supported between the pump gear shaft 10b and the pump gear shaft 10b. A pair of oil seals 16 are fitted at the boundary between the output gear shaft 10a and the pump drive gear shaft 10b at the joint between the case 4 of the PTO 1 and the case 5 of the oil pump 2. and the hydraulic oil in the case 5 of the oil pump 2 can be separated.

A fork shaft 17 is supported in the upper part of the case 4 of the PTO 1 in parallel to the output gear shaft 10a, and is movable in the axial direction. A shift fork 18 is fixed to this fork shaft 17 within the case 4 of the PTO 1, and this shift fork 18 is also fixed to the output gear 14. Then, as the forkshaft 17 moves, the output gear 1
4 moves on the spline shaft portion 13 via the shift fork 18 to connect and disconnect with the idler gear 9. In addition, Folkshaft 17
The movement position is determined by a lock ball 19.

A valve plunger 20 is supported within the case 6 of the control valve 3 so as to be orthogonal to the axis of the pump drive gear shaft 10b,
It is designed to be positioned by a lock ball 21 at each switching position of raising, stopping, and lowering.
In addition, the case 6 of the control valve 3 has a 10th
An upper port 22 connected to the piston upper chamber of the hoist cylinder 37 shown in the figure and a lower port 23 connected to the piston lower chamber of the hoist cylinder 37 are formed.

The support shaft 24 is located at a close position on the oil pump 2.
As shown in FIG. 4, the control link 25 is rotatably supported by a forkshaft connecting arm 26 extending downward from the support shaft 24, and a plunger connecting arm 2 extending laterally from the support shaft 24.
7 and a cable connection arm 28 extending downwardly parallel to the forkshaft connection arm 26. A long hole 29 is formed in the forkshaft connection arm 26 so as to extend in the axial direction of the forkshaft 17, and a connection pin 30 protruding from the outer end of the forkshaft 17 is inserted therein. A long hole 31 is also formed in the plunger connecting arm 27, into which a connecting pin 32 protruding from the outer end of the valve plunger 20 is inserted.
One end of a control cable 33 is connected to the cable connection arm 28, and the other end is connected to a dump control lever 35 mounted on the side of the steering column 34, as shown in FIG. In addition, this dump control lever 35
is positioned by a lock lever 36 at each of the raising, stopping and lowering operating positions as shown in FIG. And dump control lever 35
As a result, the control link 25 is rotated about the support shaft 24 only via the control cable 33, and the movement is directly transmitted to the forkshaft 17 and the valve plunger 20.

Next, the operation of the dump control mechanism configured as described above will be explained in detail with reference to FIGS. 6 to 9. When the dump control lever 35 is in the raised position, the operation as shown in FIG. , the rotation of the control link 25 moves the output gear 14 via the fork shaft 17 and the shift fork 18 and meshes with the idler gear 9, so that the rotation of the idler gear 9 moves the output gear 14 and the output gear shaft 1.
0a and the pump drive gear 15 through the pump drive gear shaft 10b, and the oil pump 2 is operated. On the other hand, the valve plunger 20 rises due to the rotation of the control link 25, and the hydraulic oil pumped by the oil pump 2 passes through a check valve (not shown) to the lower port 23.
From there, it is sent to the lower piston chamber of the hoist cylinder 37 shown in FIG. and,
As the piston of the hoist cylinder 37 rises, the vessel 38 shown in FIG. 10 rises. As the piston of the hoist cylinder 37 rises, the hydraulic oil in the piston upper chamber passes through the upper port 22, via the control valve 3, and returns to the oil pump 2.

When the dump control lever 35 is switched from the raised position to the stop position,
As shown in the figure, even when the control link 25 rotates, the connecting pin 30 of the fork shaft 17 remains stationary and only relatively moves within its elongated hole 29, so the fork shaft 17 does not move and the output gear 14 The meshing between the oil pump 2 and the idler gear 9 is maintained, and the oil pump 2 continues to operate.
On the other hand, the valve plunger 20 of the control valve 3 is switched to the stop position by the rotation of the control link 25, and the passage to the piston lower chamber of the hoist cylinder 37 is blocked, so that the vessel 3
8 remains constant without falling. Hydraulic oil pumped from the oil pump 2 is circulated via the control valve 3. Also, the connecting pin 30 of the forkshaft 17 is connected to the elongated hole 29 of the control link 25.
Therefore, even if the dump control lever 35 is reversely switched from the stop position to the raised position, the forkshaft 17 will not move. Therefore, the dump control lever 35 will not be moved to the raised position or the raised position while the oil pump 2 remains in operation. It can be switched to the stop position alternately. By the switching operation, the vessel 38
repeats rising and stopping alternately.

When the dump control lever 35 is switched from the stop position to the lowering position,
As shown in the figure, the output gear 14 is moved via the fork shaft 17 and the shift fork 18 by the rotation of the control link 25,
The idler gear 9 and the output gear 14 are disengaged, and the oil pump 2 does not operate. On the other hand, the valve plunger 20 of the control valve 3 is switched to the lowered position by the rotation of the control link 25, and the piston lower chamber and the piston upper chamber of the hoist cylinder 37 communicate through the lower port 23 and the upper port 22. Therefore, when the vessel 38 is in the raised position, pressure is applied to the lower chamber of the piston due to the weight of the vessel 38, and the hydraulic oil moves to the upper chamber of the piston via the control valve 3, thereby lowering the vessel 38.

When the dump control lever 35 is switched from the lowered position to the stop position, as shown in FIG. is maintained. Conversely, even when the dump control lever 35 is switched from the stop position to the lowered position, the forkshaft 17 does not move due to the action of the elongated hole 29 of the control link 25, and the oil pump 2 remains stopped as well. Therefore, the dump control lever 35 can be alternately switched to the lowering position or the stop position, and the vessel 38 can be lowered or stopped alternately.

When the dump control lever 35 is switched from the stop position to the raised position, as shown in FIG. 6A, the forkshaft 17 is moved by the rotation of the control link 25, and the oil pump 2 is operated again.

In this way, as the dump control lever 35 is switched, the fork shaft 17 and the valve plunger 20 are controlled by the rotation of the control link 25 in the operation pattern shown in FIG.

Effects of the Invention In short, according to the present invention, one shaft serves as the output gear shaft of the PTO and the drive shaft of the oil pump, and the shaft support structure supports one end of the shaft within the PTO. Since it is composed of a bearing member and a bearing member that supports the other end of the shaft within the oil pump, only bearing members are required at both ends of the dual-purpose shaft, reducing the number of bearing members and simplifying the shaft support structure. At the same time, there are no connecting parts, which not only improves transmission efficiency but also increases strength.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram showing the dump control mechanism, Figure 2 is a plan view showing the PTO, oil pump, and control valve, Figure 3 is a vertical sectional view, and Figure 4 is a section showing the connection structure of the control link part. Fig. 5 is a partial perspective view showing the lock lever, Fig. 6 is an explanatory diagram showing the operation pattern of the PTO force shaft and the valve plunger of the control valve controlled by the control link, and Fig. 7 is a partial perspective view showing the dump control lever. Fig. 8 is a vertical sectional view showing the operating states of the PTO, oil pump, and control valve when the dump control lever is in the raised position; Fig. 9 is a longitudinal sectional view showing the operating states of each when the dump control lever is in the stop position; A vertical cross-sectional view showing each operating state when the dump control lever is in the lowered position, Fig. 10 is a schematic diagram showing the hoist cylinder and vessel of the dump truck, and Figs. 11 and 12 show a conventional oil pump drive mechanism. It is a side view or sectional view shown. 1 is a PTO, 2 is an oil pump, 3 is a control valve, 4, 5, 6 is a case, 9 is an idler gear, 10 is a shaft, 10a is an output gear shaft, 10b is a pump drive gear shaft, 11 is a bearing member. ball bearing,
12 is a bearing bush as a bearing member, 14 is an output gear, and 15 is a pump drive gear.

Claims (1)

[Claims] 1. A PTO that extracts power from the engine, and a PTO that extracts power from the engine.
An oil pump driven by the TO is installed adjacently, one shaft serves as both the output gear shaft of the PTO and the drive shaft of the oil pump, and the shaft support structure is installed within the PTO. An oil pump drive mechanism for a specially equipped vehicle such as a dump truck, comprising a bearing member that supports one end of a shaft, and a bearing member that supports the other end of the shaft within an oil pump.