GB2094246A

GB2094246A - Unitary combined wheel with hydraulic drive

Info

Publication number: GB2094246A
Application number: GB8205120A
Authority: GB
Original assignee: PHB WESERHUETTE AG
Current assignee: PHB WESERHUETTE AG
Priority date: 1981-02-21
Filing date: 1982-02-22
Publication date: 1982-09-15
Also published as: DE3106453A1; AT375619B; IT8212444A0; ATA10582A; DE3106453C2; FR2500392A1; NL8200661A; AU8057382A; JPS57178964A; SE8201068L; IT1157635B; GB2094246B

Abstract

In order to provide a compact and maintenance-free combined wheel and hydraulic drive, the casing of a hydraulic motor 3, 11 is formed by a main wall 2 and a removable opposite wall 4, and a circular-section circumferential external running surface 6 is formed on the main wall for running for instance on a rail 5. The hydraulic motor 3, 11 is supported at least in part by a bearing 17 on the main wall 2. <IMAGE>

Description

SPECIFICATION Unitary, combined wheel with hydraulic drive Background of the Invention The present invention relates to a combined wheel and hydraulic drive for a main assembly, comprising a running wheel having a circular-section circumferential external running surface for rolling on a rail and a hydraulic motor. The wheel can be mounted in a sub-assembly such as a fixed carriage or bo gie, pier or subframe of the main assembly, which itself can be a large assembly such as a travelling crane or foundry vehicle and may be rail-borne, the wheel rolling on a rail.

Rail-borne cranes usually have steel running wheels. These wheels are driven by electric motors which drive the wheel axles directly by way of a clutch or other coupling and a change-ratio transmission, or drive the wheels by way of a pinion meshing with a ring gear secured to the respective wheel. Such drives have been widely used.

It is desirable to provide a maintenance4ree single-wheel drive and construct the wheel and the drive so that both can be accommodated as far as possible in the sub-assembly, without exceeding the space already available in the sub-assembly.

Conventional combined wheels and drives have the disadvantage that they usually project or overhang sideways and thus signicantly increase the amount of space required. Increasing the vertical dimension of the drive is not suitable, particularly if there are a number of wheels arranged one behind the other as the wheels can only be arranged at greater distances from one another and the compensating sub-assembly or carriage must be at a greater height.

It is known to mount a running wheel or other rotating parts on a hydraulic drive. A hydraulic hub drive is also known, in which a complete hydraulic drive is built into the hub of a wheel, and the drive may be fitted with a casing which is fixed in the rotary sense to the wheel hub. An advantage of a hydraulic drive, particulary of a hydrostatic motor, is the direct controllability of the speed of the motor and hence of the driven wheel.

In general terms, it is desirable to remove the disadvantages of known hydraulic drives, more specifically, it is desirable to provide a combined wheel and hydraulic drive which is suitable for mass production and also capable of many different applications, and which can also be accommodated without difficulty in relatively small spaces, for instance in a pier or column of a large travelling assembly or in the normal space provided for a wheel and its bearing. Futhermore, it is generally desirable to provide a combined wheel and hydraulic drive which is relatively maintenancefree.

The Invention In accordance with the present invention, the casting of the hydraulic motor includes a main wail and a removable opposite wall secured to the main wall, the hydraulic motor being essentially contained within the casing, and the main wall has the external running surface e.g. for rolling on the rail, the hydraulic motor being supported at least in part by the main wall. The invention thus provides an integrated wheel drive in which the support wall of the wheel, which will contact e.g. the rail also acts as a main wall of the hydraulic motor casing and supports at least part of the load of the hydraulic motor, the main wall and the removable wall serving for the effective outer limitation of the hydraulic drive.

In a double construction, there can be two said casings spaced apart axially and connected to each other by a shaft, a bearing being provided for mounting the shaft for rotation about the axis of said running surfaces being spaced apart for running on respective parallel rails, and a hydraulic motor being essentially contained within each respective casing.

Embodiments of the Invention The invention is further described, by way of example, with reference to the accompanying drawing, in which: Figure 1 is a vertical veri&commat;e8 section through a combined wheel and hydraulic drive in accordance with the invention, and Figure 2 is a vertical section through another combined wheel and hydraulic drive in accordance with the invention.

In Fig. 1, the combined wheel and hydraulic drive is shown mounted in a sub-assembly or carriage 1 of a rail-borne vehicle such as a travelling crane or foundry vehicle, the carriage 1 being fixed to the vehicle.

The wheel has a support wall 2 which has a circular-section circumferential external running surface 6 which directly contacts and rolls on the rail 5. The support wall 2 also acts as the main wall for partially supporting and bearing the hydraulic motor whose casing is formed by the main wall 3 on one side and an opposite, removable wall 4 on the other side, the walls 2, 4 effectively providing the outer limitation of the hydraulic drive, the only parts of the hydraulic motor which project beyond the casing are associated with the supply and valving of the hydraulic fluid. In this manner, the wheel and the drive are integrated into a closed unit which is complete in itself, forming a hydraulically-driven wheel.The casing walls 2, 4 must be suitably thickened so as to take up the forces arising from the load of the rail-borne vehicle. However, the compact drive so formed has relatively small dimensions, and also offers the advantage that all the parts associated with the hydraulic drive proper are contained within the casing and are well protected from damage and from the ingress of for instance dirt.

The wheel need not be for running on a rail 5, but can be arranged in any suitable manner. In Figs. 1 and 2, the wheels are shown provided with flanges which extend radially, but it is appreciated that these are not necessary if the wheel does not run on a rail.

The main wall 2 of the combined wheel and drive shown in Fig. 1 is integral with and made in one piece with a stub axle 2a which is shown as carrying an anti-friction bearing 2b mounted on the sub-assembly 1. In the embodiment of Fig. 2, the axle 2a is integral with and formed in one piece with respective main walls 2 of two wheels whose casings 2, 4 are spaced apart axially, their running surfaces being likewise spaced apart for running on respective parallel rails 7. The axle 2a is shown as carried in a bearing 2b in turn carried by the respective sub-assembly 8. It is not necessary that both wheels should be equipped with a hydraulic motor, but in Fig.

2, two hydraulic motors are provided and the arrangement of each is substantially identical to that shown in Fig. 1.

The specific type of hydraulic motor can be chosen to suit circumstances, but one type is described purely by way of example, it being understood that any other suitable type can be used. Parts of the hydraulic motor, for instance the hydraulic fluid ducting, are shown purely schematically; it is known how such motors function.

Referring more specifically to Fig. 1, the motor shown is a radial-piston hydrostatic unit having a non-rotary part 3 which is fixed to the sub-assembly 1 in a rotary sense by any suitably means for preventing rotation of the part 3, for instance splines or a torque arm. A similar arrangement (not shown) can be provided for the double-wheel of Fig. 2. Ducts or hoses 10 are provided for the supply and return of hydraulic fluid. The part 3 surrounds a part 11 which serves in a known manner for the valve control of the hydraulic fluid, controlling the admission and release of the fluid to cylinders 1 2 formed in the part 3.The cylinders 1 2 contain radially-reciprocable pistons 1 3 which carry rollers 14 engaging an undulating reaction or cam ring 1 5 in a known way, the cam ring 1 5 forming a rotary part of the hydraulic motor; the pistons 1 3 thus act as means for inducing relative rotary motion between the non-rotary part 3 and the rotary part or cam ring 1 5. The ring 1 5 is secured to the casing, and in effect forms part of the casing, being clamped between the walls 2, 4 by any suitable clamping means, bolts 1 6 being indicated; the cam ring 1 5 could if desired be formed in one piece with one of the walls 2 or 4. In a well known manner, the wall 4 is removable for initial assembly of the wheel and also for servicing, should such be necessary, for instance by removing the bolts 16. In order to take up moments imposed by the load and provide for proper support of the main wall 2, the end of the part 3 is supported on a short stub axle on the inner side of the wall 2 by means of a bearing 1 7 while the inner periphery of the wall 4 is supported on the part 3 by means of a bearing 18.

Claims

1. A combined wheel and hydraulic drive, comprising a hydraulic motor having a casing including a main wall and a removable opposite wall secured to the main wall, the hydraulic motor being essentially contained within the casing, the main wall having a circularsection circumferential external running surface, the hydraulic motor being supported at least in part by the main wall.

2. The combined wheel and hydraulic drive of Claim 1, wherein the motor comprises a non-rotary part supported by bearing means and a rotary part secured to and forming part of said casing, with means for inducing relative rotary movement between said non-rotary and rotary parts when pressurized hydraulic fluid is supplied to the hydraulic motor.

3. The combined wheel and hydraulic drive of Claim 2, wherein said main wall is integral with an axle providing a main bearing for the wheel, and there is a bearing for the non-rotary part of the hydraulic motor on the side of the main wall facing the removable wall and a further bearing for the non-rotary part of the hydraulic motor on the removable wall.

4. The combined wheel and hydraulic drive of any one of the preceding Claims, and comprising two said casings spaced apart axially and connected to each other by a shaft, the shaft being mounted for rotation about the axis of said running surfaces, said running surfaces being spaced apart for running on respective parallel rails, and a said hydraulic motor being contained essentially within each respective casing.

5. A combined wheel and hydraulic drive, substantially as herein described with reference to, and as shown in, Fig. 1 or Fig. 2 of the accompanying drawing.

6. An assembly comprising a sub-assembly on which is rotatably mounted the combined wheel and hydraulic drive of any one of the preceding Claims.