CA2129178A1 - Track tensioning system for tracked vehicles - Google Patents

Track tensioning system for tracked vehicles

Info

Publication number
CA2129178A1
CA2129178A1 CA 2129178 CA2129178A CA2129178A1 CA 2129178 A1 CA2129178 A1 CA 2129178A1 CA 2129178 CA2129178 CA 2129178 CA 2129178 A CA2129178 A CA 2129178A CA 2129178 A1 CA2129178 A1 CA 2129178A1
Authority
CA
Canada
Prior art keywords
piston
track
cylinder
cylinder unit
tensioning system
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
CA 2129178
Other languages
French (fr)
Inventor
Hubert Hofer
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Steyr Daimler Puch AG
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of CA2129178A1 publication Critical patent/CA2129178A1/en
Abandoned legal-status Critical Current

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B62LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62DMOTOR VEHICLES; TRAILERS
    • B62D55/00Endless track vehicles
    • B62D55/08Endless track units; Parts thereof
    • B62D55/30Track-tensioning means
    • B62D55/305Track-tensioning means acting on pivotably mounted idlers

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Devices For Conveying Motion By Means Of Endless Flexible Members (AREA)

Abstract

ABSTRACT

The tracks (1) of a tracked vehicle pass around a track adjusting wheel (2) and a number of road wheels (3), the track adjusting wheel (2) being mounted on a bell-crank axle (5) that supports a piston-cylinder unit (6), and the piston-cylinder unit (6) incorporating two cylinders (10, 11) that are arranged in series.
In order to create the simplest and most reliable track tensioning system that is possible, which permits a temporary increase in track tension during movement, and with which mobility is maintained even if the system becomes defective, the first cylinder (10) contains an oil or grease charge that is at constant pressure, and the other cylinder (11) is acted upon by pressurized hydraulic oil, by which means the whole of the piston-cylinder unit (6) is lengthened by a specific amount of travel.

Illustration: figure 1.

Description

`--`'` 212~'7~

A TRACK TENSIONING SYSTEM FOR TRACked VEHICLES

The present invention relates to a hydraulic track tensioning system for the track of a tracked vehicle, which passes over a drive sprocket, a track adjusting wheell and a number of road wheels, the track adjusting wheel being supported on a bell-crank axle that supports a hydraulic piston-cylinder unit, said piston-cylinder unit incorporating two cylinders that are arranged in series.

A track adjusting system of this kind is known, for example, from DE-A 23 58 386. In this system, the piston-cylinder unit that acts on the track ad~usting wheel is connected on one side with a dynamic hydraulic accumulator and, on the other, with a hydraulic system, which adapts the position of the track adjusting wheel to the ground clearance that has been set in order that track tension is kept constant when moving cross country.

However, when moving cross country it is not desirable to keep track tension constant. If heavy ground ~stony ground or thick mud) gets between the track and the track adjusting wheel and thus lifts the track, this can cause the track to be thrown, which can lead to destruction or loss of the track, in which case the vehicle will be unable to move. In addition, in the case of soft or boggy ground, the deformation of the run of the track that is lying on the ground can cause ground pressure peaks and increased rolling resistance. Both situations can be rectified by increasing track tension. A further disadvantage in the known system is the fact that the vehicle becomes incapable of movement if the hydraulic system becomes unserviceable.

WO-A 87/04987 describes a tensioning system for the tracks of a crawler tractor, this incorporating a piston-cylinder unit, the first cylinder being filled with grease and the second cylinder ? ~ ~ !: . ! . ~ ! . ` ..

` ` 212~1'7'~

being held at a specific pressure by means of a hydraulic system.
The normal track tension is adjusted by this. If, during operation, an obstruction becomes jammed between the track and a road wheel, the system pressure relief valve releases the track tension and the non-return valve permits a return to normal track tension. Because of the fact that the second cylinder only ensures normal track tension when under pressure, the vehicle becomes incapable of movement if the hydraulic system, or the second cylinder, respectively, becomes defective.

US-PS 4,859,006 describes a track tensioning system with a grease-filled piston-cylinder unit, in which track tension is kept constant in two ways: on the one hand, by means of a pressurized gas accumulator with respect to wear, and on the other by means of a mechanical connection between the road wheels and the track adjusting wheel with respect to road-wheel travel.
This deliberately hinders adjustment of track tension under all circumstances.

It is the task of the present invention to create the simplest and most reliable track tensioning system that is possible, which permits a temporary increase in track tension during movement and with which mobility is maintained in the event that it becomes defective.

According to the present invention, this has been achieved in that the first cylinder contains an oil or grease charge with a constant volume that corresponds to normal track tension, and in which the other cylinder can be acted upon by pressurized hydraulic oil in order to increase track tension, by which means the whole of the piston-cylinder unit is lengthened by a specific amount of travel.

Thus, the first cylinder, which is not dependent on any external hydraulic system, maintains a fixed, normal track tension. The ~ ` 2~29~

second cylinder is not pressurized when the track is at normal tension. If it becomes necessary, when moving cross country, when the driver so desires, the track tension can be increased by the required extent by lengthening by a speci~ic amount. No regulation is necessary in order to do this; all that is required is a simple and robust control valve. In addition, this measure is effective when the upper run of the track is either under tension or slack (drive sprocket at the ~ront or at the rear).

In a development of the present invention, in running gear in which the road wheels are mounted on swinging axles, it is advantageous to have one or a plurality of these swinging axles act on an additional piston-cylinder unit that is connected through a control valve to the piston-cylinder unit that supports the bell-crank axle (claim 2).

The other piston-cylinder unit thus delivers oil pressure to increase the tension of the track if the road wheel is moved up and down by irregularities in the ground. In addition, this has the effect of a shock absorber on the road wheel.

In a preferred embodiment, the other piston-cylinder unit incorporates two pressure chambers, of which the first is defined by a piston that is connected to the swinging axle and the second is defined by a spring-loaded piston, the two pressure chambers being connected on the one hand through a first non-return valve and, on the other, through a second non-return valve and the control valve (claim 3).

In this way, an oil circulation circuit that is closed in the normal state is created, and this dampens the movement of the road wheel. If, when moving cross country, track tension is to be increased, by simply closing the control valve, the movement of the road wheel will move hydraulic oil from the first into the other piston-cylinder unit until such time as the defined ~ ~` 21291 ~

lengthening of the first piston-cylinder unit is achieved. When this is done, the displacement of the spring-loaded piston corresponds precisely to its lengthening, and does this in a manner which is replicable.

In a refinement of the present invention, the volume of the second pressure chamber is equal to the volume of the second cylinder of the piston-cylinder unit, in which this has been extended by a specific amount of travel. Thus, no separate stop is required, and the end position is reached without any impact.

The present invention is described in greater detail below on the basis of the drawings appended hereto. These drawings show the following:

Figure 1: a first embodiment of the invention;
Figure 2: a second embodiment of the invention.

In figure 1, the track of an armoured vehicle is numbered 1 and this passes round a track adjusting wheel 2, a number of road wheels 3, of which only one is shown, and a drive sprocket that is located at the other end of the vehicle (this can be either at the ~ront or at the rear, and is not shown herein). The vehicle itself is only indicated by its hull 4. The track adjusting wheel 2 is supported in the known manner on a bell-crank axle that is supported on the hull 4 by way of a piston-cylinder unit 6. The road wheels 3 are supported on swinging axles 7 which are connected in the known way to transverse torque rods.

The piston-cylinder unit 6 consists of a constant volume cylinder 10 and an adjusting cylinder 11. A piston 12 fits into the constant volume cylinder 10 and defines a chamber 13 that is filled with grease, and which can be charged through a valve 14, for example, by means of a portable grease gun. The adjusting piston 15 incorporates a stop surface 16 to limit its travel and 212~ 7~

a connecting bore 17 that connects the chamber between the stop surface 16 and the cylinder 11 with a pressure chamber 18. A
pressure line 19 opens out into this pressure chamber 18 and hydraulic oil is delivered to this pressure chamber 18 through a control valve 20 from a hydraulic unit 21 that consists of a pump 22 and a pressure regulating valve 23.

In the embodiment shown in figure 2, identical parts hear the same reference numbers. The difference here lies in the fact that the pressurized hydraulic oil for the first piston-cylinder unit 6 is generated during movement by the movement of the road wheel 3, as indicated by the arrow 50, which is caused by irregularities in the ground during movement. To this end, a second piston-cylinder unit 30 is provided, and this consists of a pump cylinder 31 and an equalizing cylinder 32. Within the pump cylinder 31 a pump piston 33, which is moved by a pressure arm 34 that is connected to the swinging axle 7 defines a chamber 35. The equalizing cylinder 32 itself is mounted through a lug 36 with a stop 37 on a bracket 38 in the hull 4.

Within the equalizing cylinder 32, there is an equalizing piston 40 that de~ines an equalizing chamber 41 and is spring-loaded by a compression spring 42 in the sense of reducing the volume of the equalizing chamber 41. The equalizing chamber 41 and the pump chamber 35 are connected with each other through a suction bore 43 with the non-return valve. A pressure line 44 leads from the pump chamber 35 through a non-return valve 45, and this pressure line 44 supplies the pressure line 19. A return line 47 branches off this; this line contains a solenoid valve 47 and leads back once again into the equalizing chamber 41.

The system operates as follows: during normal movement, the adjusting cylinder 11 is not pressurized and normal track tension is maintained by the grease charge in the constant volume chamber 13. If track tension is to be increased when moving across 2.12 ~

difficult terrain, the solenoid valve 20 (figure 1) or the solenoid valve 46 (42) is activated and this displaces the adjusting piston 15 by the amount of travel that is required for the desired increase in track tension.

In the embodiment that is shown in figure 1, the pressurized hydraulic oil is delivered from a hydraulic unit 21. In the embodiment shown in figure 2, this happens as follows: moving with normal track tension, the inward movement of the pump piston 33 delivers pressurized hydraulic oil from the pump chamber 35 through the pressure line 44, through the solenoid valve 46 that is open, and the return line 47 to the equalizing chamber 41, from which the pressurized oil is drawn once again during outward movement of the pump piston 33, through the suction bore 43.

If track tension is now to be increased, the solenoid valve 46 is closed. The pressurized oil now flows from the pressure line 44 into the pressure line 19 and from there into the pressure chamber 18 which means that the piston-cylinder unit 6 is lengthened by the desired amount of travel. During the outward movement of the pump piston 33, oil is drawn out of the equalizing chamber 41 through the suction bore 43. Since, however, because the solenoid valve 46 is closed, no oil flows back through the return line 47 to the equalizing chamber, this will reduce its volume, which is possible on account of the moveable equalizing piston.

If the whole of the equalizing chamber 41 is empty, the pump piston 33 cannot draw any more oil out and the whole of the second piston-cylinder unit 30 will move in an axial direction because of the travel of the road wheels. For this reason, the lug 36 is provided with a stop 37 which then lifts from the hull 4 and so imparts the desired freedom of movement to the second piston-cylinder unit 30.

Claims (4)

1. A hydraulic track tensioning system for the track (1) of a tracked vehicle, which passes over a drive sprocket, a track adjusting wheel (2), and a number of road wheels (3), the track adjusting wheel being supported on a bell-crank axle (5) that supports a hydraulic piston-cylinder unit (6), said piston-cylinder unit incorporating two cylinders (10, 11) that are arranged in series, characterized in that the first cylinder (10) contains an oil or grease filling at a constant volume that corresponds to a normal track tension, and the other cylinder (11) can be acted upon by pressurized hydraulic oil in order to increase track tension, whereby the whole of the piston-cylinder unit (6) is lengthened by a specific amount of travel.
2. A hydraulic tensioning system as defined in claim 1, in which a road wheel (3) is attached to a swinging axle (7), characterized in that this swinging axle (7) works in conjunction with a second piston-cylinder unit (30) that is connected through a control valve (46) with the piston-cylinder unit (6) that supports the bell-crank axle (5).
3. A track tensioning system as defined in claim 2, characterized in that the second piston-cylinder unit (30) incorporates two pressure chambers (35, 41), of which the first (35) is defined by a piston (33) that is connected to the swinging axle (7) and the second (41) is defined by a spring-loaded piston (40), the two pressure chambers (35, 41) being connected, on the one hand, through a first non-return valve (43) and, on the other hand, through a second non-return valve (45) and the control valve (46).
4. A track tensioning system as defined in claim 3, characterized in that the volume of the second pressure chamber (41) is equal to the volume of the second cylinder (18) of the piston-cylinder unit (6), in which this has been lengthened by the specific amount of travel.
CA 2129178 1993-07-30 1994-07-29 Track tensioning system for tracked vehicles Abandoned CA2129178A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ATA1526/93 1993-07-30
AT152693A AT401764B (en) 1993-07-30 1993-07-30 CHAIN TENSIONER FOR TRACKED VEHICLES

Publications (1)

Publication Number Publication Date
CA2129178A1 true CA2129178A1 (en) 1995-01-31

Family

ID=3515480

Family Applications (1)

Application Number Title Priority Date Filing Date
CA 2129178 Abandoned CA2129178A1 (en) 1993-07-30 1994-07-29 Track tensioning system for tracked vehicles

Country Status (4)

Country Link
AT (1) AT401764B (en)
CA (1) CA2129178A1 (en)
DE (1) DE4423364B4 (en)
SE (1) SE510267C2 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6024183A (en) * 1997-10-24 2000-02-15 Caterpillar Inc. Track belt tension management system
RU2773132C1 (en) * 2021-06-11 2022-05-30 Федеральное государственное бюджетное образовательное Учреждение высшего образования "Воронежский государственный аграрный университет имени императора Петра 1" (ФГБОУ ВО Воронежский ГАУ) Apparatus for tensioning the track chain of a vehicle

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB0709685D0 (en) * 2007-05-19 2007-06-27 Cox Andrew S Track tensioner
CN101596920B (en) * 2009-06-30 2011-05-11 三一重工股份有限公司 Track tensioning device, track type engineering machinery and method for adjusting track tensioning force
GB2520284A (en) 2013-11-14 2015-05-20 Moorend Ltd A Support Structure
CN109094670A (en) * 2018-10-08 2018-12-28 哈尔滨工业大学 A kind of compound mobile platform of swing arm wheel shoe
US11667342B2 (en) 2019-10-03 2023-06-06 Deere & Company Active track-chain sag management systems for crawler vehicles

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2358386A1 (en) * 1973-11-23 1975-06-05 Mak Maschinenbau Gmbh Track tensioner for cross country vehicles - has a static cylinder for regulating the dynamic adjuster to ground conditions
JPS5686872A (en) * 1979-12-17 1981-07-15 Mitsubishi Heavy Ind Ltd Tensioning device for track belt
WO1987004987A1 (en) * 1986-02-25 1987-08-27 Allan Lloyd Hamblin Adjusting and recoil mechanism
FR2617545B1 (en) * 1987-07-03 1993-04-30 Applic Mach Motrices HYDROPNEUMATIC CYLINDER

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6024183A (en) * 1997-10-24 2000-02-15 Caterpillar Inc. Track belt tension management system
RU2773132C1 (en) * 2021-06-11 2022-05-30 Федеральное государственное бюджетное образовательное Учреждение высшего образования "Воронежский государственный аграрный университет имени императора Петра 1" (ФГБОУ ВО Воронежский ГАУ) Apparatus for tensioning the track chain of a vehicle

Also Published As

Publication number Publication date
DE4423364B4 (en) 2004-11-04
SE9402592L (en) 1995-01-31
DE4423364A1 (en) 1995-02-02
ATA152693A (en) 1996-04-15
AT401764B (en) 1996-11-25
SE9402592D0 (en) 1994-07-28
SE510267C2 (en) 1999-05-03

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