JPH1067239A - Forklift drive system component mounting structure - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To manufacture a frame and a drive system at low cost. A forklift including a hydraulic pump (1) driven by an engine (2) and a hydraulic motor (7) operated by hydraulic pressure supplied from the hydraulic pump to rotate driving wheels is mounted on a frame (4) as a drive system component. A hydraulic unit 3 constituted by rigidly connecting a hydraulic pump 1 to an engine 2 is supported by a frame 4, and a hydraulic motor 7
Is softly coupled to the hydraulic unit 3 via a hydraulic motor mount structure 14 having an elastic body, and the hydraulic motor 7 is supported by the frame 4 via the elastic body and the hydraulic unit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrostatic pump comprising, as drive system components, a hydraulic pump driven by an engine and a hydraulic motor operated by hydraulic pressure supplied from the hydraulic pump to rotate drive wheels. The present invention relates to a forklift in which a power transmission device (referred to as a hydrostatic transmission, hereinafter abbreviated as “HST”) is mounted on a frame, and a structure for mounting these drive system components.

[0002]

2. Description of the Related Art FIG. 9 shows an example of a structure for mounting an HST on a general vehicle. In this mounting structure, a hydraulic pump 1 is rigidly connected to an engine 2. The hydraulic unit 3 is supported by a frame 4 via a normal engine mount structure (not shown), and a hydraulic motor 7 which operates by hydraulic pressure supplied from the hydraulic pump 1 to rotate a driving wheel 6 via a differential mechanism 5 Is rigidly connected to the casing 8 of the differential mechanism 5, and the casing 8 of the differential mechanism 5 is supported by the frame 4 via a suspension structure (not shown).

In a drive system of a forklift, since a load applied to the drive wheels 6 is large, a semi-floating type support structure for heavy loads as shown in FIG. Here, the drive shaft housing tube 9 fixed to the casing 8 of the differential mechanism 5
Are inserted through a drive shaft mounting bracket 10 fixed to the frame 4 and are semi-floatingly supported by the drive shaft mounting bracket 10. Such a support structure does not pose a problem in a conventional ordinary forklift which does not employ the HST because the casing 8 of the differential mechanism 5 is rigidly connected to the engine via a transmission, but as described above, the HST adopts the HST. In such a drive system, since the hydraulic pump 1 and the hydraulic motor 7 are not usually rigidly connected, some structure for separately supporting the drive system including the hydraulic motor 7 with the frame 4 is required.

For this reason, the drive system of the forklift is provided with an HS.
In the case of employing T, a structure in which the drive shaft housing tube 9 and the drive shaft mounting bracket 10 are rigidly connected to each other by, for example, welding or bolting in order to support the drive system including the hydraulic motor 7 with the frame 4 may be adopted. Conceivable. However, such a structure is disadvantageous in strength because stress tends to concentrate on the rigid connection portion. Further, since the drive shaft mounting bracket 10 is usually bolted to the receiving plate 11 at the end of the frame 4 of the forklift as shown in FIG. 11, the distance A between the drive shaft mounting brackets 10 is fixed by the drive system. In the above structure, the dimensional accuracy of the interval A and the interval B of the receiving plate 11 of the frame 4 needs to be extremely high, which makes it difficult to manufacture and increases the manufacturing cost.

To avoid the above problem, FIG.
As shown in FIG. 1, it is conceivable to adopt a structure in which the hydraulic motor 7 is supported by an under-cross member 12 provided at a lower portion near the center of the frame 4. In such a structure, it is necessary to add an under-cross member 12 to the frame 4, which is also difficult to manufacture and increases the manufacturing cost.

On the other hand, in the drive system employing the HST as described above, as shown in FIG. 9, in the figure, the hydraulic pump 1 is moved at a position independent of the air-cooling region of the upper engine 2 by the cooling fan. Since the hydraulic unit 3 is usually rigidly connected to the engine 2, when the forklift is mounted with the HST as a drive system, the hydraulic oil circulating between the hydraulic pump 1 and the hydraulic motor 7 Cooling equipment such as an oil cooler is separately required for cooling, and this also has a problem that the manufacturing cost increases.

[0007] By the way, the HST is actually attached to the forklift.
Is mounted as a drive system, the hydraulic motor and the hydraulic pump are often arranged at positions close to each other due to space limitations. The present invention is directed to simplifying the mounting structure of the hydraulic motor and saving space by paying attention to the fact that the arrangement of the hydraulic motor and the hydraulic pump is often close to each other.

When the HST is mounted on a forklift as a drive system, the hydraulic pump and the hydraulic motor can be separated from each other. The present invention is also directed to simplifying the cooling of the hydraulic oil circulating between the hydraulic pump and the hydraulic motor by focusing on the degree of freedom of the arrangement of the hydraulic pump.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a drive system component mounting structure that advantageously solves the above-mentioned problems. The driving system component mounting structure of the forklift according to the invention includes a hydraulic pump driven by an engine and a hydraulic motor that operates by hydraulic pressure supplied from the hydraulic pump to rotate driving wheels as a driving system component on a frame. In the forklift, a hydraulic unit configured by rigidly coupling the hydraulic pump to the engine is supported by the frame, and the hydraulic motor is softly coupled to the hydraulic unit via an elastic body, and the hydraulic motor is It is characterized by being supported by the frame via an elastic body and a hydraulic unit.

According to this mounting structure, the hydraulic motor is softly connected to the hydraulic unit via the elastic body, and the hydraulic unit is allowed to swing with respect to the hydraulic motor due to the operation of the engine, while allowing the hydraulic motor to swing with respect to the hydraulic motor. Since the hydraulic motor is supported by the frame, there is no need to rigidly couple the drive system to the frame in order to support the drive system including the hydraulic motor with the frame. Since it is not necessary to make the dimensional accuracy of the frame and the drive system so high, they can be manufactured at low cost. In addition, there is no need to provide an under-cross member particularly at the lower center of the frame. Can be reduced in cost.

The elastic body for softly coupling the hydraulic motor to the hydraulic unit in the present invention may be a rubber-like elastic body or a spring, as described in the second and third aspects. If these are adopted, the flexible connection can be configured at low cost.

A hydraulic hose having both ends connected to the hydraulic motor and the hydraulic pump so as to form an oil passage between the hydraulic motor and the hydraulic pump is generally provided with a certain degree of elasticity in order to provide pressure resistance. And the rigidity, the elastic body in the present invention may be the hydraulic hose thereof, as described in claim 4. In this case, the elastic body is separately provided from the hydraulic hose. There is no need to provide it, and the flexible connection can be configured at lower cost.

On the other hand, the drive system component mounting structure for a forklift according to the present invention described in claim 5 rotates a drive wheel by operating with a hydraulic pump driven by an engine and a hydraulic pressure supplied from the hydraulic pump. In a forklift having a hydraulic motor and a drive system component mounted on a frame, the hydraulic pump is disposed in an air-cooled region of a cooling fan of the engine and supported by the frame.

According to this mounting structure, the hydraulic pump is
Located in the air cooling area by the engine cooling fan,
Since the air is cooled by the cooling fan, it is possible to easily cool the hydraulic oil circulating between the hydraulic pump and the hydraulic motor without providing any cooling equipment, thereby reducing the manufacturing cost of the forklift. it can.

According to a sixth aspect of the present invention, the hydraulic pump is provided between a cooling radiator for cooling the engine cooling water and a cooling fan located opposite to the cooling fan. It may be arranged and fixed to the engine and supported by the frame via the engine. In this case, the hydraulic pump is arranged at a position very close to the cooling fan and well hit by the cooling air. As a result, the cooling efficiency of the hydraulic pump and hence the hydraulic oil passing therethrough can be enhanced, and the hydraulic pump is fixed or rigidly connected to the engine, so that the mounting structure of the hydraulic pump can be simplified.

The hydraulic pump according to the present invention is disposed between the cooling fan and the engine, fixed to the engine, and supported by the frame via the engine. Also in this case, the hydraulic pump is fixed or rigidly connected to the engine, so that the mounting structure of the hydraulic pump can be simplified.

[0017]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In the figure, the same parts as those of the prior art are denoted by the same reference numerals, and FIG. 1 is a side view showing an embodiment of a drive system component mounting structure of a forklift according to the present invention. In the mounting structure of this embodiment, the hydraulic unit 3 formed by rigidly connecting the hydraulic pump 1 driven by the engine 2 to the engine 2 employs HST elastically via a normal engine mount structure 13. While not supported by a frame 4 similar to that of conventional ordinary forklifts,
A hydraulic motor 7 that operates by the hydraulic pressure supplied from the hydraulic pump 1 to rotate the drive wheels 6 via the differential mechanism 5
Is rigidly connected to the casing 8 of the differential mechanism 5, and the casing 8 of the differential mechanism 5 is used for heavy load as shown in FIG. Is supported by the frame 4 via the semi-floating type support structure so as to be rotatable at least around the axis of the drive wheel.

Here, since the hydraulic motor 7 is not rigidly connected to the hydraulic pump 1, a structure for separately supporting the drive system including the hydraulic motor 7 by the frame 4 is required. Therefore, in this embodiment, the motor mount structure 13 is interposed between the hydraulic pump 1 and the hydraulic motor 7, and the hydraulic motor 7 is attached to the hydraulic pump 1 by the motor mount structure 14.
And the hydraulic motor 7 is supported by the frame 4 via the motor mount structure 14 and the hydraulic unit 3 formed by rigidly connecting the hydraulic pump 1 and the engine 2.

FIG. 2 is a front view showing an example of the hydraulic motor mount structure 14, and the hydraulic motor mount structure 14 is shown in FIG.
14 forms through holes 16 near both ends of the substrate 15,
An annular groove 18 is formed on the outer peripheral surface of a cylindrical rubber-like elastic body 17,
Further, a through-hole 19 is formed at the center of the rubber-like elastic body 17, the rubber-like elastic body 17 is inserted into each of the through-holes 16, and the rubber-like elastic body is inserted into the substrate 15 at the position of the through-hole 16. 17 and the rubber-like elastic body
A bracket 21 having an L-shaped cross section is fastened and fixed to the rubber-like elastic body 17 by a bolt 20 inserted into a through hole 19 at the center of the 17. Such a hydraulic motor mount structure 14
Fixes the board 15 on the upper part of the hydraulic pump 1,
By fixing the bracket 21 to the side of the hydraulic motor 7 located above the hydraulic pump 1, the hydraulic motor 7 can be softly coupled to the hydraulic pump 1. The engine 2 of the hydraulic unit 3 that elastically supports the hydraulic motor 7, which is semi-floatably supported rotatably about the axis of the drive wheel via a casing 8, by a frame 4.
Are supported separately by a hydraulic pump 1 which can swing slightly in the left-right direction of the vehicle due to the vibrations caused by the operation of.

FIG. 3 is a front view showing another example of the hydraulic motor mount structure 14. The hydraulic motor mount structure 14 has through holes 23 near both ends of a substrate 22, while having an L-shape. The seat plate 25 is fixed to an intermediate portion of the bolt 24 formed in the base plate 22, the bolt 24 is loosely inserted into each through hole 23 of the board 22, and the coil is inserted between the seat plate 25 fixed to the bolt 24 and the board 22. It is configured such that the bolt 24 is prevented from coming off from the substrate 22 by a nut 27 which is inserted through a spring 26 and fastened to the tip of the bolt 24. Such a hydraulic motor mount structure 14
Fixes the substrate 22 on the upper part of the hydraulic pump 1,
By fixing the base of the bolt 24 to the side of the hydraulic motor 7 located above the hydraulic pump 1, the hydraulic motor 7 can be softly coupled to the hydraulic pump 1.

FIG. 4 is a front view showing still another example of the hydraulic motor mount structure 14. The hydraulic motor mount structure 14 has a cylindrical concave portion at the center of the lower surface of a disc-like rubber-like elastic body 28. 29 is formed, and a column 30 for preventing misalignment is fitted into the concave portion 29. The hydraulic motor mount structure 14 has a support 30 for the hydraulic pump 1
By fixing the upper surface of the rubber-like elastic body 28 to the lower portion of the hydraulic motor 7 located above the hydraulic pump 1, the hydraulic motor 7 can be softly coupled to the hydraulic pump 1.

FIG. 5 is a front view showing still another example of the hydraulic motor mount assembly 14. The hydraulic motor mount assembly 14 has a disc-shaped rubber-like elastic body 31 and a spherical concave portion at the center of the lower surface. While forming the curved surface 32, the upper surface 34 of the support base 33 for preventing misalignment is formed as a spherical convex curved surface corresponding to the concave curved surface 32, and the upper surface 34 of the support base 33 is formed on the lower surface of the rubber-like elastic body 31. It is configured to be in contact with the concave curved surface 32 at the center.
The hydraulic motor mount assembly 14 has its support 33 fixed to the upper part of the hydraulic pump 1, while the upper surface of the rubber-like elastic body 31 is fixed to the lower part of the hydraulic motor 7 located above the hydraulic pump 1. The hydraulic motor 7 can be softly coupled to the hydraulic pump 1.

FIG. 6 is a front view showing still another example of the hydraulic motor mount structure 14. The hydraulic motor mount structure 14 forms an oil passage between the hydraulic motor 7 and the hydraulic pump 1. It is constituted by two hydraulic hoses 35 having both ends connected to the hydraulic motor 7 and the hydraulic pump 1. The hydraulic motor mount assembly 14 can also flexibly couple the hydraulic motor 7 to the hydraulic pump 1 by the elasticity and rigidity of the hydraulic hoses 35. Here, a protection spring 36 is mounted around the hydraulic hoses 35. The hydraulic hose 35 is protected from external damage.

According to the forklift drive system component mounting structure of the above embodiment, since the drive system including the hydraulic motor 1 is supported by the frame 4, it is not necessary to rigidly couple the drive system to the frame 4. It is possible to avoid the occurrence of stress concentration at the rigid connection portion, and it is not necessary to make the dimensional accuracy of the frame 4 and the drive system so high, so that they can be manufactured at low cost.
Since there is no need to provide an under-cross member at the lower center of the frame 4, the manufacturing cost of the frame 4 can be reduced from this point as well.

It should be noted that rubber-like elastic members 17, 28, 31 as shown in FIGS. 2, 4 and 5 may be used for the hydraulic motor mount structure 14 in the above embodiment, or the hydraulic motor mount structure 14 in the embodiment shown in FIG. If a spring is used as described above, a flexible coupling between the hydraulic motor 7 and the hydraulic pump 1 can be formed at low cost, and the hydraulic motor mount structure 14 in the above embodiment is provided with an example shown in FIG. When the hydraulic hose 35 is used as described above, there is no need to provide an elastic body separately from the hydraulic hose, and the soft coupling can be configured at lower cost.

FIG. 7 is a plan view showing another embodiment of the drive system component mounting structure of the forklift according to the present invention. In the mounting structure of this embodiment, the engine 2 is mounted similarly to the previous embodiment.
The hydraulic unit 3 constituted by rigidly connecting the hydraulic pump 1 driven by the engine 2 to the engine 2 is elastically connected through a normal engine mount structure 13 to a hydraulic pump 3 similar to that of a conventional normal forklift that does not employ the HST. Frame 4
On the other hand, a hydraulic motor 7 that operates by hydraulic pressure supplied from the hydraulic pump 1 and rotates drive wheels via a differential mechanism is supported by a frame 4 via a mounting structure (not shown). ing.

Here, in order to drive the hydraulic pump 1 by the engine 2, the input shaft 1a of the hydraulic pump 1 is connected to the drive shaft 2a of the engine 2 and the hydraulic pump 1 is driven.
Is rigidly coupled to the engine 2, as shown in the figure, a radiator 42 for cooling the cooling water of the engine 2, which is arranged to face the cooling water cooling fan 41 of the engine 2 which is driven by the engine 2. Is surrounded by a radiator cover 43, and the radiator cover 43 is fixed or rigidly connected to the engine 2 by a bracket 44.
The hydraulic pump 1 is arranged at a position below the center of the cooling fan 41 between the radiator 42 and the radiator 42, and the hydraulic pump 1 is fixed or rigidly connected to the radiator cover 43 by another bracket 45. The input shaft 1a of the hydraulic pump 1 is opposed to the drive shaft 2a of the engine 2, and the shafts are connected by a coupling 46.

According to the mounting structure of this embodiment, the hydraulic pump 1 is located in the air-cooling region of the engine 2 by the cooling fan 41, and the air is cooled by the cooling fan 41 as shown by an arrow A in the figure. Air-cooled by flow, hydraulic pump 1
Hydraulic oil circulating between the hydraulic motor and the hydraulic motor can be easily cooled without providing any cooling equipment, so that the manufacturing cost of the forklift can be reduced. In addition, according to the mounting structure of this embodiment, the hydraulic pump 1 can be arranged at a position very close to the cooling fan 41 and well hit by the cooling air, so that the cooling efficiency of the hydraulic pump 1 and thus the hydraulic oil passing therethrough can be reduced. As the hydraulic pump 1 can be fixed and rigidly connected to the engine 2, the mounting structure of the hydraulic pump 1 can be simplified.

FIG. 8 is a plan view showing still another embodiment of a drive system component mounting structure of a forklift according to the present invention. In this embodiment, the mounting structure has substantially the same configuration as the embodiment shown in FIG. However, the positional relationship between the hydraulic pump 1 and the cooling fan 41 is reversed. That is, here, since the hydraulic pump 1 is driven by the engine 2,
When the input shaft 1a of the hydraulic pump 1 is connected to the drive shaft 2a of the engine 2 and the hydraulic pump 1 is rigidly connected to the engine 2, the cooling fan 41 driven by the engine 2 is connected to the cylinder of the engine 2 as shown in the figure. The cooling fan of the engine 2 is disposed at a distance more than usual from the block so as to face the radiator 42 for cooling the cooling water of the engine 2, and between the cooling fan 41 and the engine 2 below the center of the cooling fan 41. Pump 1 is disposed at a position on the side of the engine 2, and the hydraulic pump 1 is fixed or rigidly connected to the engine 2 by a bracket 47, and the input shaft 1 a of the hydraulic pump 1 is connected to the engine 2.
Face the drive shaft 2a, and couple those shafts together.
They are linked by 48.

According to the mounting structure of this embodiment,
Since the hydraulic pump 1 is located in an air-cooling region of the engine 2 by the cooling fan 41 and is air-cooled by the air flow of the cooling fan 41 as shown by an arrow A in the figure, the hydraulic pump 1 and the hydraulic motor The hydraulic oil circulating between the two can be easily cooled without providing any cooling equipment, so that the manufacturing cost of the forklift can be reduced, and the hydraulic pump 1 is fixed, that is, rigidly connected to the engine 2. Therefore, the mounting structure of the hydraulic pump 1 can be simplified.

Although the present invention has been described with reference to the illustrated examples, the present invention is not limited to the above-described example. For example, in the first embodiment, a hydraulic motor is disposed It is supported from below by a hydraulic pump,
Conversely, a hydraulic motor may be arranged below the hydraulic pump, and the hydraulic motor may be suspended and supported by the hydraulic pump. In the first embodiment described above, the hydraulic motor is supported by a hydraulic pump that forms a hydraulic unit together with the engine. However, as in the second and third embodiments, the hydraulic pump is mounted on the engine cooling fan side. In the case of disposing, a hydraulic motor is softly coupled to the engine via, for example, the hydraulic motor mount structure of the first embodiment,
The engine may support the hydraulic motor.

Further, in the second and third embodiments, the cooling fan cools the radiator for cooling the cooling water, but the cooling fan in the present invention is for cooling the air-cooled engine. May be. In the second and third embodiments, the cooling fan is driven by the engine. However, the cooling fan in the present invention may be an electric fan.

[Brief description of the drawings]

FIG. 1 is a side view showing an embodiment of a drive system component mounting structure of a forklift according to the present invention.

FIG. 2 is a front view showing an example of a hydraulic motor mount structure in the mounting structure of the embodiment.

FIG. 3 is a front view showing another example of the hydraulic motor mount structure in the mounting structure of the embodiment.

FIG. 4 is a front view showing another example of the hydraulic motor mount structure in the mounting structure of the embodiment.

FIG. 5 is a front view showing another example of the hydraulic motor mount structure in the mounting structure of the embodiment.

FIG. 6 is a front view showing another example of the hydraulic motor mount structure in the mounting structure of the embodiment.

FIG. 7 is a side view showing another embodiment of the drive system component mounting structure of the forklift of the present invention.

FIG. 8 is a side view showing still another embodiment of the drive system component mounting structure of the forklift of the present invention.

FIG. 9 is a plan view showing a conventional structure for mounting an HST on a general vehicle.

FIG. 10 is a sectional view showing a drive system mounting structure in a conventional ordinary forklift.

FIG. 11 is a perspective view showing a frame structure of the normal forklift.

FIG. 12 is a plan view illustrating a mounting structure of a hydraulic motor on a frame of the normal forklift.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hydraulic pump 2 Engine 3 Hydraulic unit 4 Frame 7 Hydraulic motor 14 Hydraulic motor mount structure 17, 28, 31 Rubber-like elastic body 26 Spring 41 Cooling fan 42 Radiator

Claims (7)

[Claims] A hydraulic pump (1) driven by an engine (2) and a hydraulic motor (7) operated by hydraulic pressure supplied from the hydraulic pump to rotate drive wheels as a drive system component. 4) A forklift mounted on the engine, wherein the hydraulic pump (1) is rigidly connected to the engine (2), and a hydraulic unit (3) is supported by the frame (4); To the hydraulic unit (3) via an elastic body (17, 26, 28, 31, 35), and the hydraulic motor (7) is connected to the frame ( 4) A drive system component mounting structure for a forklift, which is supported by (4). 2. The elastic body is a rubber-like elastic body (17, 28, 3).
The drive system component mounting structure for a forklift according to claim 1, wherein 1). 3. The drive system component mounting structure according to claim 1, wherein said elastic body is a spring. 4. The hydraulic hose (35) having both ends connected to the hydraulic motor and the hydraulic pump so as to form an oil passage between the hydraulic motor (7) and the hydraulic pump (1). 2. The drive system component mounting structure for a forklift according to claim 1, wherein: 5. A frame (1) comprising a hydraulic pump (1) driven by an engine (2) and a hydraulic motor (7) operated by hydraulic pressure supplied from the hydraulic pump to rotate driving wheels. 4) A forklift mounted on the forklift, wherein the hydraulic pump (1) is disposed in an air-cooled region of a cooling fan (41) of the engine (2) and supported by the frame (4). Forklift drive system component mounting structure. 6. The hydraulic pump (1) is disposed between the cooling fan and a cooling radiator (42) of the engine cooling water which is located opposite to the cooling fan (41). 6. The drive system component mounting structure for a forklift according to claim 5, wherein the frame is fixed to an engine and supported by the frame via the engine. 7. The hydraulic pump (1) is arranged between the cooling fan (41) and the engine, fixed to the engine, and supported by the frame (4) via the engine. The drive system component mounting structure for a forklift according to claim 5, characterized in that: