Torque-application test stand for transmissions

A torque-application test stand in which a belt drive or chain drive having two fixed belt stations and having one belt station which is movable in a linear manner between the two fixed belt stations is provided. A telescopic universal-joint propeller shaft for length compensation is arranged between the belt station which is movable in the linear manner and a bearing support for a test object. The belt station which is movable in the linear manner is moved during testing, thus producing a superimposed rotary motion of the universal-joint propeller shaft connected to the test object.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to testing equipment and, more particularly, to a torque-application test stand for transmissions.

2. Description of the Related Art

DE 10 2006 047 268 A1 discloses a loading apparatus for a test stand for testing a test object, which includes at least two loading machines. A first loading machine comprises a first electric motor, and a second loading machine includes a second electric motor. The electric motors are each designed for a predefined loading range, where the loading range of the first loading machine differs from the loading range of the second loading machine. The loading machines can be joined individually to the test object and can be connected via a coupling to transfer a torque. A range to be tested of the test object is thus covered substantially completely.

EP 0 377 950 A2 describes a machine simulation apparatus for creating an input torque for test purposes on a drive apparatus for a motor vehicle, where the machine simulation apparatus comprises a first and a second electric motor and a step-up transmission unit. An output of the step-up transmission unit can be connected to the input of the power shift transmission or drive transmission. The transmission unit includes a first input shaft, which is connected to the output of the first motor and carries a first input gearwheel. The first input gearwheel is driven by the first input shaft. In addition, the transmission unit includes a second input shaft, which is connected to the output of the second motor and carries a second input gearwheel. The second input gearwheel is driven by the second input shaft.

DE 34 24 923 A1 discloses a torque-application test stand for testing components designed for torque transfer, such as shafts, couplings, joints or gearwheels. One or more torque-application couplings, which is/are in each case integrated in a gearwheel of two transmissions is/are used for this purpose. A compact design is thus produced and realistic, extremely quick changes to rotational speed, torque and rotational direction as well as oscillation tests are possible at high frequency and in a highly accurate manner.

SUMMARY OF THE INVENTION

It is an object of the present invention is to provide a reliable and economically producible torque-application test stand for transmissions.

This and other objects and advantages are achieved in accordance with the invention by a torque-application test stand for transmissions that includes a drive motor and a drive shaft which is joined to the drive motor and which includes at least one mechanical interface for connection to a drive shaft or output shaft of a first transmission. The torque-application test stand is additionally provided with a balance shaft having at least two mechanical interfaces for connection between the output shaft of the first transmission and an output shaft of a second transmission, or for connection between the drive shaft of the first transmission and the drive shaft of the second transmission. The two transmissions are preferably identical in construction or are substantially identical in construction.

The torque-application test stand in accordance with the invention additionally includes an output shaft having at least one mechanical interface for connection to the drive shaft or output shaft of the second transmission. A circulating tensioning device, such as a chain or a belt, is connected with a positive fit to at least a first, second and third planetary gear. A shaft rotationally engaged with the first or second planetary gear is mounted in each of a first and second fixed station. The shaft mounted in the first fixed station is the drive shaft. A third fixed station movable between the first and second fixed stations in or against the direction of circulation of the tensioning device is additionally provided, and a shaft that is rotationally engaged with the third planetary gear is mounted in the third fixed station. The shaft mounted in the third fixed station forms the output shaft. The drive shaft, the first transmission, the balance shaft, the second transmission, the output shaft and the tensioning device thus form a closed drive circuit. The torque-application test stand in accordance with the invention eliminates the need for a previously conventional phase shifter transmission. As a result, a simplified test stand design and cost savings are provided.

The drive shaft is preferably additionally mounted at least in a first bearing support arranged between the first fixed station and the first transmission. Here, the output shaft is additionally mounted at least in a second bearing support arranged between the third fixed station and the second transmission. In addition, the drive shaft may have a universal-joint propeller shaft portion, such as a Cardan shaft portion, arranged between the first fixed station and the first bearing support. The output shaft includes a universal-joint propeller shaft portion arranged between the third fixed station and the second bearing support. In accordance with a particularly preferred embodiment, the universal-joint propeller shaft portion of the output shaft includes a length compensation element, i.e., a telescope element, to compensate for a linear motion of the third station.

The third fixed station is preferably movable in a linear manner, linearly between the first and second fixed stations, so that a torque applied as a result of a superimposed rotatory motion of the output shaft can be clearly defined. For example, the third fixed station may be movable in a linear manner during testing, and a superimposed rotary motion of the output shaft can be produced by a linear motion of the third fixed station to produce an applied torque.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The torque-application test stand for transmissions illustrated inFIG. 1includes a drive motor1and a drive shaft2which is joined to the drive motor1and which includes at least one mechanical interface for connection to a drive shaft or output shaft of a first transmission3. A balance shaft4is joined between the output shaft of the first transmission3and an output shaft of a second transmission5, or between the drive shaft of the first transmission3and the drive shaft of the second transmission5, and comprises corresponding mechanical interfaces for connection to drive shaft flanges or output shaft flanges of the first and second transmissions3,5. An output shaft6of the torque-application test stand is joined to a drive shaft or output shaft of the second transmission5via a mechanical interface. In the present exemplary embodiment, the second transmission5represents a test object, and both the first and second transmissions3,5are identically constructed.

FIG. 2is a perspective view illustration of the tensioning device drive system7of the torque-application test stand ofFIG. 1. The tensioning device drive system7includes a circulating tensioning device74, preferably a chain or a belt. The tensioning device74is connected with a positive fit to a total of seven planetary gears711,712,713,721,731,732,733. In addition, the tensioning device drive system7includes a first71fixed station and a second fixed station72, in each of which a shaft is mounted which is rotationally engaged with a first711planetary gear or a second planetary gear721. The shaft mounted in the first station71is the drive shaft2of the torque-application test stand. A third fixed station73, which is movable in a linear manner between the first and second fixed stations71,72either in or against the direction of circulation of the tensioning device74, is additionally provided, and a shaft which is rotationally engaged with a planetary gear731is mounted in the third fixed station73. The shaft mounted in the third station73is the output shaft6of the torque-application test stand. The drive shaft2, the first transmission3, the balance shaft4, the second transmission5, the output shaft6and the tensioning device74thus form a closed drive circuit.

During testing, the third station73is movable in a linear manner by an electric motor81, a threaded rod82joined to the electric motor81, and a slide block83driven by the threaded rod82. The slide block83is connected directly to the third station73. A superimposed rotary motion of the output shaft6can be produced by a linear motion of the third station73to produce an applied torque.

The drive shaft2is additionally mounted in a first bearing support31arranged between the first station71and the first transmission3. The output shaft6is additionally mounted in a second bearing support51arranged between the third fixed station73and the second transmission5. In addition, a third bearing support32and a fourth bearing support52are provided for mounting the drive shaft2and the output shaft6.

The drive shaft2includes a universal-joint propeller shaft portion21arranged between the first station71and the first bearing support31. The output shaft6accordingly comprises a universal-joint propeller shaft portion61arranged between the third station73and the second bearing support51. The universal-joint propeller shaft portion61of the output shaft6additionally has a telescope element as a length compensation element with regard to a linear motion of the third fixed station73.

In accordance with an alternative embodiment, instead of a third fixed station73which is movable in a linear manner between the first71and second stations72, at least one planetary gear712,713,721,732can be formed displaceably at the first fixed station71, the second fixed station72and/or the third fixed station73so as to change the extent of the tensioning device. The third fixed station73is also fixed in this case. An extension of the tensioning device74between the first and second fixed stations72,71, with the extension being effective for a tensioning means transmission, can be changed by displacement of at least one planetary gear712,713,721,732. As a result, torque is applied between the drive shaft2and the output shaft6. For example, an application of torque can be produced by repositioning at least one planetary gear713,732arranged between the first and third fixed stations73,71. Here, at least one outer planetary gear712,721at the first fixed station71or the second fixed station72is additionally displaced in terms of its axial position to compensate for the length of the tensioning means. In accordance with an alternative embodiment, the second and third fixed stations72,73can be united to form a combined, fixed station in which the output shaft6is mounted.